WorldWideScience

Sample records for vacuum fluctuation effects

  1. Dark energy: Vacuum fluctuations, the effective phantom phase, and holography

    International Nuclear Information System (INIS)

    Elizalde, E.; Nojiri, S.; Odintsov, S. D.; Wang Peng

    2005-01-01

    We aim at the construction of dark energy models without exotic matter but with a phantomlike equation of state (an effective phantom phase). The first model we consider is decaying vacuum cosmology where the fluctuations of the vacuum are taken into account. In this case, the phantom cosmology (with an effective, observational ω being less than -1 ) emerges even for the case of a real dark energy with a physical equation of state parameter ω larger than -1. The second proposal is a generalized holographic model, which is produced by the presence of an infrared cutoff. It also leads to an effective phantom phase, which is not a transient one as in the first model. However, we show that quantum effects are able to prevent its evolution towards a big rip singularity

  2. Big Bang or vacuum fluctuation

    International Nuclear Information System (INIS)

    Zel'dovich, Ya.B.

    1980-01-01

    Some general properties of vacuum fluctuations in quantum field theory are described. The connection between the ''energy dominance'' of the energy density of vacuum fluctuations in curved space-time and the presence of singularity is discussed. It is pointed out that a de-Sitter space-time (with the energy density of the vacuum fluctuations in the Einstein equations) that matches the expanding Friedman solution may describe the history of the Universe before the Big Bang. (P.L.)

  3. Random numbers from vacuum fluctuations

    International Nuclear Information System (INIS)

    Shi, Yicheng; Kurtsiefer, Christian; Chng, Brenda

    2016-01-01

    We implement a quantum random number generator based on a balanced homodyne measurement of vacuum fluctuations of the electromagnetic field. The digitized signal is directly processed with a fast randomness extraction scheme based on a linear feedback shift register. The random bit stream is continuously read in a computer at a rate of about 480 Mbit/s and passes an extended test suite for random numbers.

  4. Random numbers from vacuum fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yicheng; Kurtsiefer, Christian, E-mail: christian.kurtsiefer@gmail.com [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Center for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Chng, Brenda [Center for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore)

    2016-07-25

    We implement a quantum random number generator based on a balanced homodyne measurement of vacuum fluctuations of the electromagnetic field. The digitized signal is directly processed with a fast randomness extraction scheme based on a linear feedback shift register. The random bit stream is continuously read in a computer at a rate of about 480 Mbit/s and passes an extended test suite for random numbers.

  5. A theoretical model for investigating the effect of vacuum fluctuations on the electromechanical stability of nanotweezers

    Science.gov (United States)

    Farrokhabadi, A.; Mokhtari, J.; Koochi, A.; Abadyan, M.

    2015-06-01

    In this paper, the impact of the Casimir attraction on the electromechanical stability of nanowire-fabricated nanotweezers is investigated using a theoretical continuum mechanics model. The Dirichlet mode is considered and an asymptotic solution, based on path integral approach, is applied to consider the effect of vacuum fluctuations in the model. The Euler-Bernoulli beam theory is employed to derive the nonlinear governing equation of the nanotweezers. The governing equations are solved by three different approaches, i.e. the modified variation iteration method, generalized differential quadrature method and using a lumped parameter model. Various perspectives of the problem, including the comparison with the van der Waals force regime, the variation of instability parameters and effects of geometry are addressed in present paper. The proposed approach is beneficial for the precise determination of the electrostatic response of the nanotweezers in the presence of Casimir force.

  6. Maxwell electrodynamics subjected to quantum vacuum fluctuations

    International Nuclear Information System (INIS)

    Gevorkyan, A. S.; Gevorkyan, A. A.

    2011-01-01

    The propagation of electromagnetic waves in the vacuum is considered taking into account quantum fluctuations in the limits of Maxwell-Langevin (ML) equations. For a model of “white noise” fluctuations, using ML equations, a second order partial differential equation is found which describes the quantum distribution of virtual particles in vacuum. It is proved that in order to satisfy observed facts, the Lamb Shift etc, the virtual particles should be quantized in unperturbed vacuum. It is shown that the quantized virtual particles in toto (approximately 86 percent) are condensed on the “ground state” energy level. It is proved that the extension of Maxwell electrodynamics with inclusion of the vacuum quantum field fluctuations may be constructed on a 6D space-time continuum with a 2D compactified subspace. Their influence on the refraction indexes of vacuum is studied.

  7. Vacuum fluctuations of the supersymmetric field in curved background

    International Nuclear Information System (INIS)

    Bilić, Neven; Domazet, Silvije; Guberina, Branko

    2012-01-01

    We study a supersymmetric model in curved background spacetime. We calculate the effective action and the vacuum expectation value of the energy momentum tensor using a covariant regularization procedure. A soft supersymmetry breaking induces a nonzero contribution to the vacuum energy density and pressure. Assuming the presence of a cosmic fluid in addition to the vacuum fluctuations of the supersymmetric field an effective equation of state is derived in a self-consistent approach at one loop order. The net effect of the vacuum fluctuations of the supersymmetric fields in the leading adiabatic order is a renormalization of the Newton and cosmological constants.

  8. Vacuum fluctuations of the supersymmetric field in curved background

    Energy Technology Data Exchange (ETDEWEB)

    Bilic, Neven, E-mail: bilic@thphys.irb.hr [Rudjer Boskovic Institute, POB 180, HR-10002 Zagreb (Croatia); Domazet, Silvije, E-mail: sdomazet@irb.hr [Rudjer Boskovic Institute, POB 180, HR-10002 Zagreb (Croatia); Guberina, Branko, E-mail: guberina@thphys.irb.hr [Rudjer Boskovic Institute, POB 180, HR-10002 Zagreb (Croatia)

    2012-01-16

    We study a supersymmetric model in curved background spacetime. We calculate the effective action and the vacuum expectation value of the energy momentum tensor using a covariant regularization procedure. A soft supersymmetry breaking induces a nonzero contribution to the vacuum energy density and pressure. Assuming the presence of a cosmic fluid in addition to the vacuum fluctuations of the supersymmetric field an effective equation of state is derived in a self-consistent approach at one loop order. The net effect of the vacuum fluctuations of the supersymmetric fields in the leading adiabatic order is a renormalization of the Newton and cosmological constants.

  9. Electroweak vacuum instability and renormalized Higgs field vacuum fluctuations in the inflationary universe

    Energy Technology Data Exchange (ETDEWEB)

    Kohri, Kazunori [Institute of Particle and Nuclear Studies, KEK, 1-1 Oho, Tsukuba 305-0801 (Japan); Matsui, Hiroki, E-mail: kohri@post.kek.jp, E-mail: matshiro@post.kek.jp [The Graduate University for Advanced Studies (SOKENDAI), 1-1 Oho, Tsukuba 305-0801 (Japan)

    2017-08-01

    In this work, we investigated the electroweak vacuum instability during or after inflation. In the inflationary Universe, i.e., de Sitter space, the vacuum field fluctuations < δ φ {sup 2} > enlarge in proportion to the Hubble scale H {sup 2}. Therefore, the large inflationary vacuum fluctuations of the Higgs field < δ φ {sup 2} > are potentially catastrophic to trigger the vacuum transition to the negative-energy Planck-scale vacuum state and cause an immediate collapse of the Universe. However, the vacuum field fluctuations < δ φ {sup 2} >, i.e., the vacuum expectation values have an ultraviolet divergence, and therefore a renormalization is necessary to estimate the physical effects of the vacuum transition. Thus, in this paper, we revisit the electroweak vacuum instability from the perspective of quantum field theory (QFT) in curved space-time, and discuss the dynamical behavior of the homogeneous Higgs field φ determined by the effective potential V {sub eff}( φ ) in curved space-time and the renormalized vacuum fluctuations < δ φ {sup 2} >{sub ren} via adiabatic regularization and point-splitting regularization. We simply suppose that the Higgs field only couples the gravity via the non-minimal Higgs-gravity coupling ξ(μ). In this scenario, the electroweak vacuum stability is inevitably threatened by the dynamical behavior of the homogeneous Higgs field φ, or the formations of AdS domains or bubbles unless the Hubble scale is small enough H < Λ {sub I} .

  10. Chiral vacuum fluctuations in quantum gravity.

    Science.gov (United States)

    Magueijo, João; Benincasa, Dionigi M T

    2011-03-25

    We examine tensor perturbations around a de Sitter background within the framework of Ashtekar's variables and its cousins parameterized by the Immirzi parameter γ. At the classical level we recover standard cosmological perturbation theory, with illuminating insights. Quantization leads to real novelties. In the low energy limit we find a second quantized theory of gravitons which displays different vacuum fluctuations for right and left gravitons. Nonetheless right and left gravitons have the same (positive) energies, resolving a number of paradoxes suggested in the literature. The right-left asymmetry of the vacuum fluctuations depends on γ and the ordering of the Hamiltonian constraint, and it would leave a distinctive imprint in the polarization of the cosmic microwave background, thus opening quantum gravity to observational test.

  11. Vacuum fluctuations and topological Casimir effect in Friedmann-Robertson-Walker cosmologies with compact dimensions

    International Nuclear Information System (INIS)

    Saharian, A.A.; Mkhitaryan, A.L.

    2010-01-01

    We investigate the Wightman function, the vacuum expectation values of the field squared and the energy-momentum tensor for a massless scalar field with general curvature coupling parameter in spatially flat Friedmann-Robertson-Walker universes with an arbitrary number of toroidally compactified dimensions. The topological parts in the expectation values are explicitly extracted and in this way the renormalization is reduced to that for the model with trivial topology. In the limit when the comoving lengths of the compact dimensions are very short compared to the Hubble length, the topological parts coincide with those for a conformal coupling and they are related to the corresponding quantities in the flat spacetime by standard conformal transformation. This limit corresponds to the adiabatic approximation. In the opposite limit of large comoving lengths of the compact dimensions, in dependence of the curvature coupling parameter, two regimes are realized with monotonic or oscillatory behavior of the vacuum expectation values. In the monotonic regime and for non-conformally and non-minimally coupled fields the vacuum stresses are isotropic and the equation of state for the topological parts in the energy density and pressures is of barotropic type. For conformal and minimal couplings the leading terms in the corresponding asymptotic expansions vanish and the vacuum stresses, in general, are anisotropic, though the equation of state remains of barotropic type. In the oscillatory regime, the amplitude of the oscillations for the topological part in the expectation value of the field squared can be either decreasing or increasing with time, whereas for the energy-momentum tensor the oscillations are damping. The limits of validity of the adiabatic approximation are discussed. (orig.)

  12. Parametric Amplification of Vacuum Fluctuations in a Spinor Condensate

    DEFF Research Database (Denmark)

    Klempt, C.; Topic, O.; Gebreyesus, G.

    2010-01-01

    to correlated pair creation in the mF=±1 states from an initial mF=0 condensate, which acts as a vacuum for mF≠0. Although this pair creation from a pure mF=0 condensate is ideally triggered by vacuum fluctuations, unavoidable spurious initial mF=±1 atoms induce a classical seed which may become the dominant...... triggering mechanism. We show that pair creation is insensitive to a classical seed for sufficiently large magnetic fields, demonstrating the dominant role of vacuum fluctuations. The presented system thus provides a direct path towards the generation of nonclassical states of matter....

  13. Brownian motion in Robertson-Walker spacetimes from electromagnetic vacuum fluctuations

    International Nuclear Information System (INIS)

    Bessa, Carlos H. G.; Bezerra, V. B.; Ford, L. H.

    2009-01-01

    We consider the effects of the vacuum fluctuations of a quantized electromagnetic field on particles in an expanding universe. We find that these particles typically undergo Brownian motion and acquire a nonzero mean squared velocity that depends on the scale factor of the universe. This Brownian motion can be interpreted as due to noncancellation of anticorrelated vacuum fluctuations in the time-dependent background spacetime. Alternatively, one can interpret this effect as the particles acquiring energy from the background spacetime geometry, a phenomenon that cannot occur in a static spacetime. We treat several types of coupling between the electromagnetic field and the particles and several model universes. We also consider both free particles, which, on the average, move on geodesics, and particles in bound systems. There are significant differences between these two cases, which illustrates that nongeodesic motion alters the effects of the vacuum fluctuations. We discuss the possible applications of this Brownian motion effect to cosmological scenarios.

  14. Spontaneous excitation of a circularly accelerated atom coupled to electromagnetic vacuum fluctuations

    International Nuclear Information System (INIS)

    Jin, Yao; Hu, Jiawei; Yu, Hongwei

    2014-01-01

    We study, using the formalism proposed by Dalibard, Dupont-Roc and Cohen-Tannoudji, the contributions of the vacuum fluctuation and radiation reaction to the rate of change of the mean atomic energy for a circularly accelerated multilevel atom coupled to vacuum electromagnetic fields in the ultrarelativistic limit. We find that the balance between vacuum fluctuation and radiation reaction is broken, which causes spontaneous excitations of accelerated ground state atoms in vacuum. Unlike for a circularly accelerated atom coupled to vacuum scalar fields, the contribution of radiation reaction is also affected by acceleration, and this term takes the same form as that of a linearly accelerated atom coupled to vacuum electromagnetic fields. For the contribution of vacuum fluctuations, we find that in contrast to the linear acceleration case, terms proportional to the Planckian factor are replaced by those proportional to a non-Planck exponential term, and this indicates that the radiation perceived by a circularly orbiting observer is no longer thermal as is in the linear acceleration case. However, for an ensemble of two-level atoms, an effective temperature can be defined in terms of the atomic transition rates, which is found to be dependent on the transition frequency of the atom. Specifically, we calculate the effective temperature as a function of the transition frequency and find that in contrast to the case of circularly accelerated atoms coupled to the scalar field, the effective temperature in the current case is always larger than the Unruh temperature. -- Highlights: •We study the spontaneous excitation of a circularly accelerated atom. •Contribution of radiation reaction to the excitation is affected by acceleration. •The radiation perceived by a circularly orbiting observer is no longer thermal. •An effective temperature can be defined in terms of atomic transition rates. •Effective temperature is larger than Unruh temperature and frequency-dependent

  15. Quantum noise on a point charge from electromagnetic squeezed vacuum fluctuations

    International Nuclear Information System (INIS)

    Wu, Tai-Hung; Hsiang, Jen-Tsung; Lee, Da-Shin

    2010-01-01

    The effect of quantum noises on a point charge from electromagnetic squeezed vacuum fluctuations is studied. Here a novel reduction phenomenon in velocity dispersion is found in the situation when the particle barely moves. It shows that the velocity dispersion of the charge can be reduced below the value solely given by the normal vacuum states of the electromagnetic fields by using an appropriate choice of the squeeze parameters. This may be viewed as a transient phenomenon. Optimally utilizing this reduction scheme for gravitational wave detection is possible, but challenging.

  16. Quantum noise on a point charge from electromagnetic squeezed vacuum fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tai-Hung; Hsiang, Jen-Tsung; Lee, Da-Shin [National Dong-Hwa University, Hua-lien, Taiwan (China)

    2010-09-15

    The effect of quantum noises on a point charge from electromagnetic squeezed vacuum fluctuations is studied. Here a novel reduction phenomenon in velocity dispersion is found in the situation when the particle barely moves. It shows that the velocity dispersion of the charge can be reduced below the value solely given by the normal vacuum states of the electromagnetic fields by using an appropriate choice of the squeeze parameters. This may be viewed as a transient phenomenon. Optimally utilizing this reduction scheme for gravitational wave detection is possible, but challenging.

  17. Vacuum fluctuations in an ancestor vacuum: A possible dark energy candidate

    Science.gov (United States)

    Aoki, Hajime; Iso, Satoshi; Lee, Da-Shin; Sekino, Yasuhiro; Yeh, Chen-Pin

    2018-02-01

    We consider an open universe created by bubble nucleation, and study possible effects of our "ancestor vacuum," a de Sitter space in which bubble nucleation occurred, on the present universe. We compute vacuum expectation values of the energy-momentum tensor for a minimally coupled scalar field, carefully taking into account the effect of the ancestor vacuum by the Euclidean prescription. We pay particular attention to the so-called supercurvature mode, a non-normalizable mode on a spatial slice of the open universe, which has been known to exist for sufficiently light fields. This mode decays in time most slowly, and may leave residual effects of the ancestor vacuum, potentially observable in the present universe. We point out that the vacuum energy of the quantum field can be regarded as dark energy if mass of the field is of order the present Hubble parameter or smaller. We obtain preliminary results for the dark energy equation of state w (z ) as a function of the redshift.

  18. Electromagnetic vacuum fluctuations around a cosmic string in de Sitter spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Saharian, A.A.; Saharyan, N.A. [Yerevan State University, Department of Physics, Yerevan (Armenia); Manukyan, V.F. [Gyumri State Pedagogical Institute, Department of Physics and Mathematics, Gyumri (Armenia)

    2017-07-15

    The electromagnetic field correlators are evaluated around a cosmic string in background of (D + 1)-dimensional dS spacetime assuming that the field is prepared in the Bunch-Davies vacuum state. The correlators are presented in the decomposed form where the string-induced topological parts are explicitly extracted. With this decomposition, the renormalization of the local vacuum expectation values (VEVs) in the coincidence limit is reduced to the one for dS spacetime in the absence of the cosmic string. The VEVs of the squared electric and magnetic fields, and of the vacuum energy density are investigated. Near the string they are dominated by the topological contributions and the effects induced by the background gravitational field are small. In this region, the leading terms in the topological contributions are obtained from the corresponding VEVs for a string on the Minkowski bulk multiplying by the conformal factor. At distances from the string larger than the curvature radius of the background geometry, the pure dS parts in the VEVs dominate. In this region, for spatial dimensions D > 3, the influence of the gravitational field on the topological contributions is crucial and the corresponding behavior is essentially different from that for a cosmic string on the Minkowski bulk. There are well-motivated inflationary models which produce cosmic strings. We argue that, as a consequence of the quantum-to-classical transition of super-Hubble electromagnetic fluctuations during inflation, in the post-inflationary era these strings will be surrounded by large-scale stochastic magnetic fields. These fields could be among the distinctive features of the cosmic strings produced during the inflation and also of the corresponding inflationary models. (orig.)

  19. Bose-Einstein condensate collapse and dynamical squeezing of vacuum fluctuations

    International Nuclear Information System (INIS)

    Calzetta, E.A.; Hu, B.L.

    2003-01-01

    We analyze the phenomena of condensate collapse, as described by Donley et al. [Nature 412, 295 (2001)] and N. Claussen [Ph. D thesis, University of Colorado, 2003 (unpublished)] by focusing on the behavior of excitations or fluctuations above the condensate, as driven by the dynamics of the condensate, rather than the dynamics of the condensate alone or the kinetics of the atoms. The dynamics of the condensate squeezes and amplifies the quantum excitations, mixing the positive and negative frequency components of their wave functions thereby creating particles that appear as bursts and jets. By analyzing the changing amplitude and particle content of these excitations, our simple physical picture explains well the overall features of the collapse phenomena and provides excellent quantitative fits with experimental data on several aspects, such as the scaling behavior of the collapse time and the number of particles in the jet. The prediction of the bursts at this level of approximation is less than satisfactory but may be improved by including the backreaction of the excitations on the condensate. The mechanism behind the dominant effect--parametric amplification of vacuum fluctuations and freezing of modes outside of horizon--is similar to that of cosmological particle creation and structure formation in a rapid quench (which is fundamentally different from Hawking radiation in black holes). This shows that Bose-Einstein condensate dynamics is a promising venue for doing 'laboratory cosmology'

  20. Quantum fluctuations in the dressed vacuum of a bosonic model system

    International Nuclear Information System (INIS)

    Wagner, R E; Su, Q; Grobe, R; Acosta, S; Glasgow, S A

    2012-01-01

    Quantum fluctuations and the polarizability of the vacuum state are sometimes interpreted in terms of virtual particles that come into and out of existence for a limited amount of time. We study the spatial and temporal properties of these auxiliary particles on a numerical space-time grid for a one-dimensional model system. This approach permits us to compute the average distance between virtual particles and their lifetime. The creation dynamics of the virtual particles from the bare vacuum state is also examined. (paper)

  1. Vacuum fluctuations of a confined massive field in two dimensions

    International Nuclear Information System (INIS)

    Hays, P.

    1979-01-01

    The zero-point energy of a massive scalar field confined to a two-dimensional M. I. T. bag model, is calculated. Since the cutoff sum over modes cannot be explicitly summed, the Green's function method, developed earlier, is applied. The Green's function is constructed by two different methods and the results compared. Divergences which occure when the cutoff is removed can be absorbed into a redefinition of the bag constant. The effect of the remaining finite piece of the zero-point energy on the bag energy spectrum is studied

  2. Protecting quantum coherence of two-level atoms from vacuum fluctuations of electromagnetic field

    International Nuclear Information System (INIS)

    Liu, Xiaobao; Tian, Zehua; Wang, Jieci; Jing, Jiliang

    2016-01-01

    In the framework of open quantum systems, we study the dynamics of a static polarizable two-level atom interacting with a bath of fluctuating vacuum electromagnetic field and explore under which conditions the coherence of the open quantum system is unaffected by the environment. For both a single-qubit and two-qubit systems, we find that the quantum coherence cannot be protected from noise when the atom interacts with a non-boundary electromagnetic field. However, with the presence of a boundary, the dynamical conditions for the insusceptible of quantum coherence are fulfilled only when the atom is close to the boundary and is transversely polarizable. Otherwise, the quantum coherence can only be protected in some degree in other polarizable direction. -- Highlights: •We study the dynamics of a two-level atom interacting with a bath of fluctuating vacuum electromagnetic field. •For both a single and two-qubit systems, the quantum coherence cannot be protected from noise without a boundary. •The insusceptible of the quantum coherence can be fulfilled only when the atom is close to the boundary and is transversely polarizable. •Otherwise, the quantum coherence can only be protected in some degree in other polarizable direction.

  3. Spontaneous excitation of a static multilevel atom coupled with electromagnetic vacuum fluctuations in Schwarzschild spacetime

    International Nuclear Information System (INIS)

    Zhou Wenting; Yu Hongwei

    2012-01-01

    We study the spontaneous excitation of a radially polarized static multilevel atom outside a spherically symmetric black hole in multipolar interaction with quantum electromagnetic fluctuations in the Boulware, Unruh and Hartle-Hawking vacuum states. We find that spontaneous excitation does not occur in the Boulware vacuum, and, in contrast to the scalar field case, the spontaneous emission rate is not well behaved at the event horizon as a result of the blow-up of the proper acceleration of the static atom. However, spontaneous excitation can take place both in the Unruh and the Hartle-Hawking vacua as if there were thermal radiation from the black hole. Distinctive features in contrast to the scalar field case are the existence of a term proportional to the proper acceleration squared in the rate of change of the mean atomic energy in the Unruh and the Hartle-Hawking vacua and the structural similarity in the spontaneous excitation rate between the static atoms outside a black hole and uniformly accelerated ones in a flat space with a reflecting boundary, which is particularly dramatic at the event horizon where a complete equivalence exists. (paper)

  4. Fluctuation charge effects in ionization fronts

    International Nuclear Information System (INIS)

    Arrayas, Manuel; Trueba, Jose L; Baltanas, J P

    2008-01-01

    In this paper, we study the effects of charge fluctuations on the propagation of both negative and positive ionization fronts in streamer discharges. We show that fronts accelerate when random charge creation events are present. This effect might play a similar role to photoionization in order to make the front move faster

  5. Fluctuation charge effects in ionization fronts

    Energy Technology Data Exchange (ETDEWEB)

    Arrayas, Manuel; Trueba, Jose L [Area de Electromagnetismo, Universidad Rey Juan Carlos, Camino del Molino s/n, 28943 Fuenlabrada, Madrid (Spain); Baltanas, J P [Departamento de Fisica Aplicada II, Universidad de Sevilla, Av. Reina Mercedes 2, 41012 Sevilla (Spain)

    2008-05-21

    In this paper, we study the effects of charge fluctuations on the propagation of both negative and positive ionization fronts in streamer discharges. We show that fronts accelerate when random charge creation events are present. This effect might play a similar role to photoionization in order to make the front move faster.

  6. Vacuum level effects on gait characteristics for unilateral transtibial amputees with elevated vacuum suspension.

    Science.gov (United States)

    Xu, Hang; Greenland, Kasey; Bloswick, Donald; Zhao, Jie; Merryweather, Andrew

    2017-03-01

    The elevated vacuum suspension system has demonstrated unique health benefits for amputees, but the effect of vacuum pressure values on gait characteristics is still unclear. The purpose of this study was to investigate the effects of elevated vacuum levels on temporal parameters, kinematics and kinetics for unilateral transtibial amputees. Three-dimensional gait analysis was conducted in 9 unilateral transtibial amputees walking at a controlled speed with five vacuum levels ranging from 0 to 20inHg, and also in 9 able-bodied subjects walking at self-preferred speed. Repeated ANOVA and Dunnett's t-test were performed to determine the effect of vacuum level and limb for within subject and between groups. The effect of vacuum level significantly affected peak hip external rotation and external knee adduction moment. Maximum braking and propulsive ground reaction forces generally increased for the residual limb and decreased for the intact limb with increasing vacuum. Additionally, the intact limb experienced an increased loading due to gait asymmetry for several variables. There was no systematic vacuum level effect on gait. Higher vacuum levels, such as 15 and 20inHg, were more comfortable and provided some relief to the intact limb, but may also increase the risk of osteoarthritis of the residual limb due to the increased peak external hip and knee adduction moments. Very low vacuum should be avoided because of the negative effects on gait symmetry. A moderate vacuum level at 15inHg is suggested for unilateral transtibial amputees with elevated vacuum suspension. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Fluctuation effects in bulk polymer phase behavior

    International Nuclear Information System (INIS)

    Bates, F.S.; Rosedale, J.H.; Stepanek, P.; Lodge, T.P.; Wiltzius, P.; Hjelm R, Jr.; Fredrickson, G.H.

    1990-01-01

    Bulk polymer-polymer, and block copolymer, phase behaviors have traditionally been interpreted using mean-field theories. Recent small-angle neutron scattering (SANS) studies of critical phenomena in model binary polymer mixtures confirm that non-mean-field behavior is restricted to a narrow range of temperatures near the critical point, in close agreement with the Ginzburg criterion. In contrast, strong derivations from mean-field behavior are evident in SANS and rheological measurements on model block copolymers more than 50C above the order-disorder transition (ODT), which can be attributed to sizeable composition fluctuations. Such fluctuation effects undermine the mean-field assumption, conventionally applied to bulk polymers, and result in qualitative changes in phase behavior, such as the elimination of a thermodynamic stability limit in these materials. The influence of fluctuation effects on block copolymer and binary mixture phase behavior is compared and contrasted in this presentation

  8. Magnetic fluctuations in the quantized vacuum of the Georgi-Glashow model on the lattice

    International Nuclear Information System (INIS)

    Mitryushkin, V.K.; Zadorozhnyj, A.M.

    1987-01-01

    Influence of (electro)magnetic fluctuations on the phase structure of the 4D-Georgi-Glashow model on the lattice. The distributions of (electro)magnetic fluxes and different correlations were measured using the Monte-Carlo method

  9. Inflaton and metric fluctuations in the early universe from a 5D vacuum state

    Energy Technology Data Exchange (ETDEWEB)

    Membiela, Agustin [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350 (7600) Mar del Plata (Argentina)]. E-mail: membiela@argentina.com; Bellini, Mauricio [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350 (7600) Mar del Plata (Argentina) and Consejo Nacional de Ciencia y Tecnologia (CONICET) (Argentina)]. E-mail: mbellini@mdp.edu.ar

    2006-04-20

    In this Letter we complete a previously introduced formalism to study the gauge-invariant metric fluctuations from a noncompact Kaluza-Klein theory of gravity, to study the evolution of the early universe. The evolution of both, metric and inflaton field fluctuations are reciprocally related. We obtain that <{delta}{rho}>/{rho}{sub b} depends on the coupling of {phi} with {delta}{phi} and the spectral index of its spectrum is 0.9483

  10. Inflaton and metric fluctuations in the early universe from a 5D vacuum state

    Science.gov (United States)

    Membiela, Agustin; Bellini, Mauricio

    2006-04-01

    In this Letter we complete a previously introduced formalism to study the gauge-invariant metric fluctuations from a noncompact Kaluza Klein theory of gravity, to study the evolution of the early universe. The evolution of both, metric and inflaton field fluctuations are reciprocally related. We obtain that /ρ depends on the coupling of Φ with δφ and the spectral index of its spectrum is 0.9483

  11. Inflaton and metric fluctuations in the early universe from a 5D vacuum state

    International Nuclear Information System (INIS)

    Membiela, Agustin; Bellini, Mauricio

    2006-01-01

    In this Letter we complete a previously introduced formalism to study the gauge-invariant metric fluctuations from a noncompact Kaluza-Klein theory of gravity, to study the evolution of the early universe. The evolution of both, metric and inflaton field fluctuations are reciprocally related. We obtain that /ρ b depends on the coupling of Φ with δφ and the spectral index of its spectrum is 0.9483 1 <1

  12. Vacuum fluctuations and radiation reaction contributions to the resonance dipole-dipole interaction between two atoms near a reflecting boundary

    Science.gov (United States)

    Zhou, Wenting; Rizzuto, Lucia; Passante, Roberto

    2018-04-01

    We investigate the resonance dipole-dipole interaction energy between two identical atoms, one in the ground state and the other in the excited state, interacting with the electromagnetic field in the presence of a perfectly reflecting plane boundary. The atoms are prepared in a correlated (symmetric or antisymmetric) Bell-type state. Following a procedure due to Dalibard et al. [J. Dalibard et al., J. Phys. (Paris) 43, 1617 (1982);, 10.1051/jphys:0198200430110161700 J. Phys. (Paris) 45, 637 (1984), 10.1051/jphys:01984004504063700], we separate the contributions of vacuum fluctuations and radiation reaction (source) field to the resonance interaction energy between the two atoms and show that only the source field contributes to the interatomic interaction, while vacuum field fluctuations do not. By considering specific geometric configurations of the two-atom system with respect to the mirror and specific choices of dipole orientations, we show that the presence of the mirror significantly affects the resonance interaction energy and that different features appear with respect to the case of atoms in free space, for example, a change in the spatial dependence of the interaction. Our findings also suggest that the presence of a boundary can be exploited to tailor and control the resonance interaction between two atoms, as well as the related energy transfer process. The possibility of observing these phenomena is also discussed.

  13. Vacuum fluctuations of twisted fields in the space time of cosmic strings

    International Nuclear Information System (INIS)

    Matsas, G.E.A.

    1990-01-01

    A twisted scalar field conformally coupled to gravitation is used to calculate the vacuum stress-energy tensor in the background spacetime generated by an infinite straight gauge cosmic string. The result has an absolute numerical value close to the one obtained with a non-twisted conformal scalar field but their signals are opposite. (author) [pt

  14. Energy transfer between two vacuum-gapped metal plates: Coulomb fluctuations and electron tunneling

    Science.gov (United States)

    Zhang, Zu-Quan; Lü, Jing-Tao; Wang, Jian-Sheng

    2018-05-01

    Recent experimental measurements for near-field radiative heat transfer between two bodies have been able to approach the gap distance within 2 nm , where the contributions of Coulomb fluctuation and electron tunneling are comparable. Using the nonequilibrium Green's function method in the G0W0 approximation, based on a tight-binding model, we obtain for the energy current a Caroli formula from the Meir-Wingreen formula in the local equilibrium approximation. Also, the Caroli formula is consistent with the evanescent part of the heat transfer from the theory of fluctuational electrodynamics. We go beyond the local equilibrium approximation to study the energy transfer in the crossover region from electron tunneling to Coulomb fluctuation based on a numerical calculation.

  15. Quantum random number generator based on quantum nature of vacuum fluctuations

    Science.gov (United States)

    Ivanova, A. E.; Chivilikhin, S. A.; Gleim, A. V.

    2017-11-01

    Quantum random number generator (QRNG) allows obtaining true random bit sequences. In QRNG based on quantum nature of vacuum, optical beam splitter with two inputs and two outputs is normally used. We compare mathematical descriptions of spatial beam splitter and fiber Y-splitter in the quantum model for QRNG, based on homodyne detection. These descriptions were identical, that allows to use fiber Y-splitters in practical QRNG schemes, simplifying the setup. Also we receive relations between the input radiation and the resulting differential current in homodyne detector. We experimentally demonstrate possibility of true random bits generation by using QRNG based on homodyne detection with Y-splitter.

  16. Dynamical effects of QCD vacuum structure

    International Nuclear Information System (INIS)

    Ferreira, Erasmo

    1994-01-01

    The role of the QCD vacuum structure in the determination of the properties of states and processes occurring in the confinement regime of QCD is reviewed. The finite range of the vacuum correlations is discussed, and an analytical form is suggested for the correlation functions. The role of the vacuum quantum numbers in the phenomenology of high-energy scattering is reviewed. The vacuum correlation model of non-perturbative QCD is mentioned as a bridge between the fundamental theory and the description of the experiments. (author). 13 refs., 1 fig

  17. Effects of dissipation and fluctuation in preheating

    International Nuclear Information System (INIS)

    Vartuli, Rodrigo; Ramos, Rudnei de O.

    2006-01-01

    In this paper, we study the effects of dissipation and fluctuation in preheating after inflation. The effective equation of motion for a scalar field χ interacting with lighter fields is derived using the field theoretical method of closed time path due to Schwinger, winch is suitable to study nonequilibrium and time dependent process. In this derivation the emergent equation is intrinsically dissipative and stochastic in nature. The resulting dynamics is then studied both analytically and numerically. The results obtained are then discussed for then relevance for the reheating epoch right after an inflationary phase(preheating) for the case of the evolution of the scalar field χ and its decay into fermion. (author)

  18. The Unruh effect and quantum fluctuations of electrons in storage rings

    International Nuclear Information System (INIS)

    Bell, J.S.; Leinaas, J.M.

    1987-01-01

    The quantum fluctuation of electron orbits in ideal storage rings is a sort of Fulling-Unruh effect (heating by acceleration in vacuum). To spell this out, the effect is analyzed in an appropriate comoving, and so accelerating and rotating, co-ordinate system. The depolarization of the electrons is a related effect, but is greatly complicated by spin-orbit coupling. This analysis confirms the standard result for the polarization, except in the neighbourhood of a narrow resonance. (orig.)

  19. The Unruh effect and quantum fluctuations of electrons in storage rings

    International Nuclear Information System (INIS)

    Bell, J.S.; Leinaas, J.M.

    1995-01-01

    The quantum fluctuation of electron orbits in ideal storage rings is a sort of Fulling-Unruh effect (heating by acceleration in vacuum). To spell this out, the effect is analyzed in an appropriate comoving, and so accelerating and rotating, co-ordinate system. The depolarization of the electrons is a related effect, but is greatly complicated by spin-orbit coupling. This analysis confirms the standard result for the polarization, except in the neighbourhood of a narrow resonance. (author)

  20. Quantum vacuum effects from boundaries of designer potentials

    NARCIS (Netherlands)

    Konopka, T.J.

    2009-01-01

    Vacuum energy in quantum field theory, being the sum of zero-point energies of all field modes, is formally infinite but yet, after regularization or renormalization, can give rise to finite observable effects. One way of understanding how these effects arise is to compute the vacuum energy in an

  1. The Effect of Forcing on Vacuum Radiation

    OpenAIRE

    Jones-Smith, Katherine; Mathur, Harsh; Lowenstein, Ashton

    2018-01-01

    Vacuum radiation has been the subject of theoretical study in both cosmology and condensed matter physics for many decades. Recently there has been impressive progress in experimental realizations as well. Here we study vacuum radiation when a field mode is driven both parametrically and by a classical source. We find that in the Heisenberg picture the field operators of the mode undergo a Bogolyubov transformation combined with a displacement, in the Schr\\"odinger picture the oscillator evol...

  2. Effect of electropolishing on vacuum furnace design

    Directory of Open Access Journals (Sweden)

    Sutanwi Lahiri

    2015-03-01

    Full Text Available The use of thermal shields of materials having low emissivity in vacuum furnaces is well-known. However, the surface condition of the heat shields is one of the most important factors governing their efficiency as radiation resistances. The emissivity of the thermal shields dictates the power rating of the heaters in furnace design. The unpolished materials used in the heater tests showed poor performance leading to loss of a signi­ficant percentage of the input power. The present work deals with the refur­bishment of the radiation heat shields used in a furnace for heating graphite structure. The effect of refurbishment of the heat shields by the buffing and subsequently electro­polishing was found to improve the performance of the shields as heat reflectors. The com­position of the electrolyte was chosen in such a way that the large shields of Mo, Inconel and SS can be polished using the same reagents in different ratios. The present work deals with the development of a standard electropolishing procedure for large metallic sheets and subsequently qualifying them by roughness and emissivity measure­ments. The improvement noted in the shielding efficiency of the furnace in the subsequent runs is also discussed here.

  3. Semiclassical gravitoelectromagnetic inflation in a Lorentz gauge: Seminal inflaton fluctuations and electromagnetic fields from a 5D vacuum state

    International Nuclear Information System (INIS)

    Membiela, Federico Agustin; Bellini, Mauricio

    2010-01-01

    Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. The difference with other previous works is that in this one we use a Lorentz gauge. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of magnetic field modes during the early inflationary epoch of the universe on cosmological scales.

  4. Semiclassical gravitoelectromagnetic inflation in a Lorentz gauge: Seminal inflaton fluctuations and electromagnetic fields from a 5D vacuum state

    Energy Technology Data Exchange (ETDEWEB)

    Membiela, Federico Agustin, E-mail: membiela@mdp.edu.a [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina); Instituto de Fisica de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Bellini, Mauricio, E-mail: mbellini@mdp.edu.a [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina); Instituto de Fisica de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina)

    2010-02-22

    Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. The difference with other previous works is that in this one we use a Lorentz gauge. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of magnetic field modes during the early inflationary epoch of the universe on cosmological scales.

  5. Semiclassical gravitoelectromagnetic inflation in a Lorentz gauge: Seminal inflaton fluctuations and electromagnetic fields from a 5D vacuum state

    Science.gov (United States)

    Membiela, Federico Agustín; Bellini, Mauricio

    2010-02-01

    Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. The difference with other previous works is that in this one we use a Lorentz gauge. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of magnetic field modes during the early inflationary epoch of the universe on cosmological scales.

  6. Temperature effects in the valence fluctuation of europium intermetallic compounds

    International Nuclear Information System (INIS)

    Menezes, O.L.T. de; Troper, A.; Gomes, A.A.

    1978-03-01

    A previously reported model for valence fluctuations in europium compound in order to account for thermal occupation effect. Experimental results are critically discussed and new experiments are suggested

  7. Advances in vacuum extraction technology for effective subsurface remediation

    International Nuclear Information System (INIS)

    Dodson, M.E.; Pezzullo, J.A.; Piniewski, R.J.

    1994-01-01

    Vacuum extraction technology has become one of the most widely acclaimed methods for remediating soils contaminated by petroleum hydrocarbons and volatile organic compounds. Removal of the source of contamination in the soil is often the first step in effective control of groundwater contamination. Though originally thought effective only for removal of light-end hydrocarbons from permeable vadose-zone soils, vacuum extraction can now be adapted to address situations of low-permeable soils, heavier-end hydrocarbons and groundwater contamination. This paper reviews four innovative modifications to the vacuum extraction process and how they solve a wide variety of subsurface contamination problems. The modifications, or processes, reviewed include: vacuum-extraction-enhanced bioremediation, groundwater sparging, pneumatic soil fracturing, and soil heating

  8. Thin porous indium tin oxide nanoparticle films: effects of annealing in vacuum and air

    International Nuclear Information System (INIS)

    Ederth, J.; Hultaaker, A.; Niklasson, G.A.; Granqvist, C.G.; Heszler, P.; Doorn, A.R. van; Jongerius, M.J.; Burgard, D.

    2005-01-01

    Electrical and optical properties were investigated in porous thin films consisting of In 2 O 3 :Sn (indium tin oxide; ITO) nanoparticles. The temperature-dependent resistivity was successfully described by a fluctuation-induced tunneling model, indicating a sample morphology dominated by clusters of ITO nanoparticles separated by insulating barriers. An effective-medium model, including the effect of ionized impurity scattering, was successfully fitted to measured reflectance and transmittance. Post-deposition treatments were carried out at 773 K for 2 h in both air and vacuum. It is shown that vacuum annealing increases either the barrier width or the area between two conducting clusters in the samples and, furthermore, an extra optical absorption occurs close to the band gap. A subsequent air annealing then reduces the effect of the barriers on the electrical properties and diminishes the absorption close to the band gap. (orig.)

  9. Effects of phase transition induced density fluctuations on pulser dynamics

    International Nuclear Information System (INIS)

    Bagchi, Partha; Das, Arpan; Srivastava, Ajit M.; Layek, Biswanath

    2016-01-01

    We show that density fluctuations during phase transitions in pulsar cores may have non-trivial effects on pulsar timings, and may also possibly account for glitches and anti-glitches. These density fluctuations invariably lead to non-zero off-diagonal components of the moment of inertia, leading to transient wobbling of star. Thus, accurate measurements of pulsar timing and intensity modulations (from wobbling) may be used to identify the specific pattern of density fluctuations, hence the particular phase transition, occurring inside the pulsar core. Changes in quadrupole moment from rapidly evolving density fluctuations during the transition, with very short time scales, may provide a new source for gravitational waves. (author)

  10. Fluctuations in macroscopically agitated plasma:quasiparticles and effective temperature

    International Nuclear Information System (INIS)

    Sosenko, P.P.; Gresillon, D.

    1994-01-01

    Fluctuations in the plasma, in which macroscopic fluid-like motion is agitated due to large-scale and low-frequency electro-magnetic fields, are studied. Such fields can be produced by external factors or internally, for example due to turbulence. Fluctuation spectral distributions are calculated with regard to the renormalization of the transition probability for a test-particle and of the test-particle shielding. If the correlation length for the random fluid-like motion is large as compared to the fluctuation scale lengths, then the fluctuation spectral distributions can be explained in terms of quasiparticles originating from macroscopic plasma agitation and of an effective temperature

  11. Nonequilibrium fluctuations in micro-MHD effects on electrodeposition

    International Nuclear Information System (INIS)

    Aogaki, Ryoichi; Morimoto, Ryoichi; Asanuma, Miki

    2010-01-01

    In copper electrodeposition under a magnetic field parallel to electrode surface, different roles of two kinds of nonequilibrium fluctuations for micro-magnetohydrodynamic (MHD) effects are discussed; symmetrical fluctuations are accompanied by the suppression of three dimensional (3D) nucleation by micro-MHD flows (the 1st micro-MHD effect), whereas asymmetrical fluctuations controlling 2D nucleation yield secondary nodules by larger micro-MHD flows (the 2nd micro-MHD effect). Though the 3D nucleation with symmetrical fluctuations is always suppressed by the micro-MHD flows, due to the change in the rate-determining step from electron transfer to mass transfer, the 2D nucleation with asymmetrical fluctuations newly turns unstable, generating larger micro-MHD flows. As a result, round semi-spherical deposits, i.e., secondary nodules are yielded. Using computer simulation, the mechanism of the 2nd micro-MHD effect is validated.

  12. Equilibrium & Nonequilibrium Fluctuation Effects in Biopolymer Networks

    Science.gov (United States)

    Kachan, Devin Michael

    speculate that cells take advantage of this equilibrium effect by tuning near the transition point, where small changes in free cross-linker density will affect large structural rearrangements between free filament networks and networks of bundles. Cells are naturally found far from equilibrium, where the active influx of energy from ATP consumption controls the dynamics. Motor proteins actively generate forces within biopolymer networks, and one may ask how these differ from the random stresses characteristic of equilibrium fluctuations. Besides the trivial observation that the magnitude is independent of temperature, I find that the processive nature of the motors creates a temporally correlated, or colored, noise spectrum. I model the network with a nonlinear scalar elastic theory in the presence of active driving, and study the long distance and large scale properties of the system with renormalization group techniques. I find that there is a new critical point associated with diverging correlation time, and that the colored noise produces novel frequency dependence in the renormalized transport coefficients. Finally, I study marginally elastic solids which have vanishing shear modulus due to the presence of soft modes, modes with zero deformation cost. Although network coordination is a useful metric for determining the mechanical response of random spring networks in mechanical equilibrium, it is insufficient for describing networks under external stress. In particular, under-constrained networks which are fluid-like at zero load will dynamically stiffen at a critical strain, as observed in numerical simulations and experimentally in many biopolymer networks. Drawing upon analogies to the stress induced unjamming of emulsions, I develop a kinetic theory to explain the rigidity transition in spring and filament networks. Describing the dynamic evolution of non-affine deformation via a simple mechanistic picture, I recover the emergent nonlinear strain

  13. Effective tension and fluctuations in active membranes.

    Science.gov (United States)

    Loubet, Bastien; Seifert, Udo; Lomholt, Michael Andersen

    2012-03-01

    We calculate the fluctuation spectrum of the shape of a lipid vesicle or cell exposed to a nonthermal source of noise. In particular, we take constraints on the membrane area and the volume of fluid that it encapsulates into account when obtaining expressions for the dependency of the membrane tension on the noise. We then investigate three possible origins of the nonthermal noise taken from the literature: A direct force, which models an external medium pushing on the membrane, a curvature force, which models a fluctuating spontaneous curvature, and a permeation force coming from an active transport of fluid through the membrane. For the direct force and curvature force cases, we compare our results to existing experiments on active membranes.

  14. Effects of the fermionic vacuum polarization in QED

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, M.F.X.P.; Barone, F.A. [IFQ-Universidade Federal de Itajuba, Itajuba, MG (Brazil); Barone, F.E.

    2018-01-15

    Some effects of vacuum polarization in QED due to the presence of field sources are investigated. We focus on effects with no counter-part in Maxwell electrodynamics. The Uehling interaction energy between two stationary point-like charges is calculated exactly in terms of Meijer-G functions. Effects induced on a hydrogen atom by the vacuum polarization in the vicinity of a Dirac string are considered. We also calculate the interaction between two parallel Dirac strings and corrections to the energy levels of a quantum particle constrained to move on a ring circumventing a solenoid. (orig.)

  15. Effective tension and fluctuations in active membranes

    OpenAIRE

    Loubet, Bastien; Seifert, Udo; Lomholt, Michael Andersen

    2011-01-01

    We calculate the fluctuation spectrum of the shape of a lipid vesicle or cell exposed to a nonthermal source of noise. In particular we take into account constraints on the membrane area and the volume of fluid that it encapsulates when obtaining expressions for the dependency of the membrane tension on the noise. We then investigate three possible origins of the non-thermal noise taken from the literature: A direct force, which models an external medium pushing on the membrane. A curvature f...

  16. Effect of density fluctuations on ECCD in ITER and TCV

    Directory of Open Access Journals (Sweden)

    Coda S.

    2012-09-01

    Full Text Available Density fluctuations near the edge of tokamak plasmas can affect the propagation of electron cyclotron (EC waves. In the present paper, the EC wave propagation in a fluctuating equilibrium is determined using the ray-tracing code C3PO. The evolution of the electron distribution function is calculated self-consistently with the EC wave damping using the 3-D Fokker-Planck solver LUKE. The cumulative effect of fluctuations results in a significant broadening of the current profile combined with a fluctuating power deposition profile. This mechanism improves the simulation of fully non-inductive EC discharges in the TCV tokamaks. Predictive simulations for ITER show that density fluctuations could make the stabilization of NTMs in ITER more challenging.

  17. Quantum Fluctuations and the Unruh effect in strongly-coupled conformal field theories

    Science.gov (United States)

    Cáceres, Elena; Chernicoff, Mariano; Güijosa, Alberto; Pedraza, Juan F.

    2010-06-01

    Through the AdS/CFT correspondence, we study a uniformly accelerated quark in the vacuum of strongly-coupled conformal field theories in various dimensions, and determine the resulting stochastic fluctuations of the quark trajectory. From the perspective of an inertial observer, these are quantum fluctuations induced by the gluonic radiation emitted by the accelerated quark. From the point of view of the quark itself, they originate from the thermal medium predicted by the Unruh effect. We scrutinize the relation between these two descriptions in the gravity side of the correspondence, and show in particular that upon transforming the conformal field theory from Rindler space to the open Einstein universe, the acceleration horizon disappears from the boundary theory but is preserved in the bulk. This transformation allows us to directly connect our calculation of radiation-induced fluctuations in vacuum with the analysis by de Boer et al. of the Brownian motion of a quark that is on average static within a thermal medium. Combining this same bulk transformation with previous results of Emparan, we are also able to compute the stress-energy tensor of the Unruh thermal medium.

  18. Vacuum-polarization effects in global monopole space-times

    International Nuclear Information System (INIS)

    Mazzitelli, F.D.; Lousto, C.O.

    1991-01-01

    The gravitational effect produced by a global monopole may be approximated by a solid deficit angle. As a consequence, the energy-momentum tensor of a quantum field will have a nonzero vacuum expectation value. Here we study this ''vacuum-polarization effect'' around the monopole. We find explicit expressions for both left-angle φ 2 right-angle ren and left-angle T μν right-angle ren for a massless scalar field. The back reaction of the quantum field on the monopole metric is also investigated

  19. The VAK of vacuum fluctuation, Spontaneous self-organization and complexity theory interpretation of high energy particle physics and the mass spectrum

    International Nuclear Information System (INIS)

    El Naschie, M.S.

    2003-01-01

    The paper is a rather informal introduction to the concepts and results of the E-infinity Cantorian theory of quantum physics. The fundamental tools of complexity theory and non-linear dynamics (Hausdorff dimensions, fat fractals, etc.) are used to give what we think to be a new interpretation of high energy physics and to determine the corresponding mass-spectrum. Particular attention is paid to the role played by the VAK, KAM theorem, Arnold diffusion, Newhaus sinks and knot theory in determining the stability of an elementary 'particle-wave' which emerges in self-organizatory manner out of sizzling vacuum fluctuation

  20. Effect of altering local protein fluctuations using artificial intelligence

    Science.gov (United States)

    Nishiyama, Katsuhiko

    2017-03-01

    The fluctuations in Arg111, a significantly fluctuating residue in cathepsin K, were locally regulated by modifying Arg111 to Gly111. The binding properties of 15 dipeptides in the modified protein were analyzed by molecular simulations, and modeled as decision trees using artificial intelligence. The decision tree of the modified protein significantly differed from that of unmodified cathepsin K, and the Arg-to-Gly modification exerted a remarkable effect on the peptide binding properties. By locally regulating the fluctuations of a protein, we may greatly alter the original functions of the protein, enabling novel applications in several fields.

  1. Effect of altering local protein fluctuations using artificial intelligence

    Directory of Open Access Journals (Sweden)

    Katsuhiko Nishiyama

    2017-03-01

    Full Text Available The fluctuations in Arg111, a significantly fluctuating residue in cathepsin K, were locally regulated by modifying Arg111 to Gly111. The binding properties of 15 dipeptides in the modified protein were analyzed by molecular simulations, and modeled as decision trees using artificial intelligence. The decision tree of the modified protein significantly differed from that of unmodified cathepsin K, and the Arg-to-Gly modification exerted a remarkable effect on the peptide binding properties. By locally regulating the fluctuations of a protein, we may greatly alter the original functions of the protein, enabling novel applications in several fields.

  2. Plasma expansion into vacuum with charge separation effect

    International Nuclear Information System (INIS)

    Murakami, Masakatsu

    2008-01-01

    Plasma expansion into vacuum and resultant ion acceleration are studied theoretically. A new self-similar solution is found to describe free expansion of a finite plasma mass into vacuum with a full account of charge separation effects. It is argued that the normalized plasma size Λ R/λ D plays the dominant role in determining the whole ion energy spectrum and thus the maximum ion kinetic energy, where R and λ D are the plasma scale length and the Debye length, respectively. The analytical model is compared with experiments to show excellent agreement

  3. Analysis of effective electrical parameters for CFETR vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xufeng; Xu, Weiwei, E-mail: wwxu@ipp.ac.cn; Du, Shuangsong; Zheng, Jinxing

    2016-11-15

    Highlights: • The eddy current distribution and variation of CFETR vacuum vessel during plasma disruption have been calculated. • Effective electrical parameters can be derived from the eddy current characters. • The method for eddy current and effective electrical parameters is suit for the complex shell with arbitrary shape. - Abstract: The electrical parameters of CFETR (China Fusion Engineering Test Reactor) vacuum vessel are very important to the design of control system and power supply system. Effective electrical parameters are relevant to the dynamic of eddy current. For complex structure, the distribution of eddy current can’t be obtained by analytical form. A method is presented to solve the eddy current of the vacuum vessel in this paper. The effective electrical parameters can be got from the eddy current distribution and variation. The time constant of the CFETR vacuum vessel is derived from the decay characteristics of the eddy current. And the effective resistance and inductance can be derived from the viewpoint of energy for a certain distribution of eddy current.

  4. Effect of pressure fluctuations on Richtmyer-Meshkov coherent structures

    Science.gov (United States)

    Bhowmick, Aklant K.; Abarzhi, Snezhana

    2016-11-01

    We investigate the formation and evolution of Richtmyer Meshkov bubbles after the passage of a shock wave across a two fluid interface in the presence of pressure fluctuations. The fluids are ideal and incompressible and the pressure fluctuations are scale invariant in space and time, and are modeled by a power law time dependent acceleration field with exponent -2. Solutions indicate sensitivity to pressure fluctuations. In the linear regime, the growth of curvature and bubble velocity is linear. The growth rate is dominated by the initial velocity for weak pressure fluctuations, and by the acceleration term for strong pressure fluctuations. In the non-linear regime, the bubble curvature is constant and the solutions form a one parameter family (parametrized by the bubble curvature). The solutions are shown to be convergent and asymptotically stable. The physical solution (stable fastest growing) is a flat bubble for small pressure fluctuations and a curved bubble for large pressure fluctuations. The velocity field (in the frame of references accounting for the background motion) involves intense motion of the fluids in a vicinity of the interface, effectively no motion of the fluids away from the interfaces, and formation of vortical structures at the interface. The work is supported by the US National Science Foundation.

  5. Scale-invariant scalar metric fluctuations during inflation: non-perturbative formalism from a 5D vacuum

    International Nuclear Information System (INIS)

    Anabitarte, M.; Bellini, M.; Madriz Aguilar, Jose Edgar

    2010-01-01

    We extend to 5D an approach of a 4D non-perturbative formalism to study scalar metric fluctuations of a 5D Riemann-flat de Sitter background metric. In contrast with the results obtained in 4D, the spectrum of cosmological scalar metric fluctuations during inflation can be scale invariant and the background inflaton field can take sub-Planckian values. (orig.)

  6. The Thick Market Effect on Local Unemployment Rate Fluctuations

    OpenAIRE

    Li Gan; Qinghua Zhang

    2005-01-01

    This paper studies how the thick market effect influences local unemployment rate fluctuations. The paper presents a model to demonstrate that the average matching quality improves as the number of workers and firms increases. Unemployed workers accumulate in a city until the local labor market reaches a critical minimum size, which leads to cyclical fluctuations in the local unemployment rates. Since larger cities attain the critical market size more frequently, they have shorter unemploymen...

  7. Effect of pressure on the vacuum cooling of iceberg lettuce

    Energy Technology Data Exchange (ETDEWEB)

    Ozturk, Hande Mutlu [Pamukkale University, Food Engineering Department, Faculty of Engineering, Denizli (Turkey); Ozturk, Harun Kemal [Pamukkale University, Mechanical Engineering Department, Faculty of Engineering, 20070 Kinikli, Denizli (Turkey)

    2009-05-15

    Vacuum cooling is known as a rapid evaporative cooling technique for any porous product which has free water. The aim of this paper is to apply vacuum cooling technique to the cooling of the iceberg lettuce and show the pressure effect on the cooling time and temperature decrease. The results of vacuum cooling are also compared with conventional cooling (cooling in refrigerator) for different temperatures. Vacuum cooling of iceberg lettuce at 0.7 kPa is about 13 times faster than conventional cooling of iceberg lettuce at 6 C. It has been also found that it is not possible to decrease the iceberg lettuce temperature below 10 C if vacuum cooling method is used and vacuum pressure is set to 1.5 kPa. (author) [French] Le refroidissement sous vide est connu comme une technique evaporative rapide refroidissant pour n'importe quel produit poreux qui a de l'eau libre. Le but de ce papier est d'appliquer le refroidissement sous vide pour le refroidissement de la laitue et examiner l'effet de la pression sur le temps de refroidissement et la diminution de temperature. Les resultats de refroidissement sous vide sont aussi compares avec le refroidissement conventionnel (refroidissement dans le refrigerateur) pour les differentes temperatures. Le refroidissement a vide de laitue a 0.7 kPa est environ 13 fois plus vite que le refroidissement conventionnel de laitue croquante a 6 C. Il a ete aussi constate qu'il n'est pas possible de diminuer la temperature de laitue ci-dessous 10 C si le refroidissement sous vide est utilise comme methode et la pression a vide est montree a 1.5 kPa. (orig.)

  8. Effects of phase transition induced density fluctuations on pulsar dynamics

    Directory of Open Access Journals (Sweden)

    Partha Bagchi

    2015-07-01

    Full Text Available We show that density fluctuations during phase transitions in pulsar cores may have non-trivial effects on pulsar timings, and may also possibly account for glitches and anti-glitches. These density fluctuations invariably lead to non-zero off-diagonal components of the moment of inertia, leading to transient wobbling of star. Thus, accurate measurements of pulsar timing and intensity modulations (from wobbling may be used to identify the specific pattern of density fluctuations, hence the particular phase transition, occurring inside the pulsar core. Changes in quadrupole moment from rapidly evolving density fluctuations during the transition, with very short time scales, may provide a new source for gravitational waves.

  9. Different ways of looking at the electromagnetic vacuum

    International Nuclear Information System (INIS)

    Milonni, P.W.

    1987-01-01

    Some thoughts on the electromagnetic vacuum are presented in connection with the vacuum and source fields as alternative physical bases for understanding spontaneous emission, the Lamb shift, Casimir effects, van der Waals forces, and the ''thermalization'' of vacuum fluctuations for a uniformly accelerated observer

  10. Casimir effect and the quantum vacuum

    International Nuclear Information System (INIS)

    Jaffe, R.L.

    2005-01-01

    In discussions of the cosmological constant, the Casimir effect is often invoked as decisive evidence that the zero-point energies of quantum fields are ''real.'' On the contrary, Casimir effects can be formulated and Casimir forces can be computed without reference to zero-point energies. They are relativistic, quantum forces between charges and currents. The Casimir force (per unit area) between parallel plates vanishes as α, the fine structure constant, goes to zero, and the standard result, which appears to be independent of α, corresponds to the α→∞ limit

  11. Effect of programmed circadian temperature fluctuations on ...

    African Journals Online (AJOL)

    to our knowledge of the effects of temperature on the population dynamics of freshwater snails and its bearing on their .... 28"C regime as reflected by the net reproduction rate recorded in Table 1. It was demonstrated by De Kock & .... ANDREW ARlHA, H.G. & BIRCH, L.C. 1954. The distribution and abundance of animals.

  12. Effect of Alfvenic fluctuations on the solar wind

    International Nuclear Information System (INIS)

    Chien, T.H.

    1974-01-01

    The major source of microscale fluctuations in the interplanetary medium due to the outwardly propagating Alfven waves is considered. The effect of the Alfven waves on the supersonic expansion of the solar wind is studied under the assumption that the motion of the interplanetary medium can be resolved physically into a comparatively smooth and slowly varying mesoscale flow and field with very irregular disordered incompressible microscale Alfvenic fluctuations superposed on it. The important features of the solar wind such as heat conduction flux, spiral interplanetary magnetic field, and proton thermal anisotropy are included in the theory. For inviscid, steady state, spherically symmetrical model of the solar wind, the two-fluid formulation of the background mesoscale MHD equations is obtained. The results show that during the expansion process, fluctuation energy is converted into the kinetic energy of the solar wind. Due to the presence of the Alfvenic fluctuations, the velocity of the solar wind is about 5 percent higher than that without considering the fluctuations. (U.S.)

  13. The effects of vacuum polarization on thermonuclear reaction rates

    Science.gov (United States)

    Gould, Robert J.

    1990-01-01

    Added to the pure Coulomb potential, the contribution from vacuum polarization increases the barrier, reducing the wave function (u) for reacting nuclei within the range of nuclear forces. The cross section and reaction rate are then reduced accordingly by a factor proportional to u squared. The effect is treated by evaluating the vacuum polarization potential as a small correction to the Coulomb term, then computing u in a WKB formulation. The calculation is done analytically employing the small r power-series expansion for the Uehling potential to express the final result in terms of convenient parameters. At a temperature of 1.4 x 10 to the 7th K the (negative) correction is 1.3 percent for the fundamental fusion process p + p yields d + e(+) + nu.

  14. Vector Susceptibility of QCD Vacuum from an Effective Quark-Quark Interaction

    Institute of Scientific and Technical Information of China (English)

    ZONG Hong-Shi; QI Shi; CHEN Wei; WU Xiao-Hua

    2003-01-01

    .A new approach for calculating vacuum susceptibilities from an effective quark-quark interaction model is derived. As a special case, the vector vacuum susceptibility is calculated. A comparison with the results of the previous approaches is given.

  15. Fluctuations of the baryonic flux-tube junction from effective string theory

    International Nuclear Information System (INIS)

    Pfeuffer, Melanie; Bali, Gunnar S.; Panero, Marco

    2009-01-01

    In quenched QCD, where the dynamic creation of quark-antiquark pairs out of the vacuum is neglected, a confined baryonic system composed of three static quarks exhibits stringlike behavior at large interquark separation, with the formation of flux tubes characterized by the geometry of the so-called Y ansatz. We study the fluctuations of the junction of the three flux tubes, assuming the dynamics to be governed by an effective bosonic string model. We show that the asymptotic behavior of the effective width of the junction grows logarithmically with the distance between the sources, with the coefficient depending on the number of joining strings, on the dimension of spacetime and on the string tension.

  16. Mikheyev-smirnov-wolfenstein effects in vacuum oscillations

    Science.gov (United States)

    Friedland

    2000-07-31

    We point out that for solar neutrino oscillations with the mass-squared difference of Deltam(2) approximately 10(-10)-10(-9) eV(2), i.e., in the so-called vacuum oscillation range, the solar matter effects are non-negligible, particularly for the low energy pp neutrinos. One consequence of this is that the values of the mixing angle straight theta and pi/2-straight theta are not equivalent, making it necessary to consider the entire physical range of the mixing angle 0

  17. Mikheyev-Smirnov-Wolfenstein Effects in Vacuum Oscillations

    International Nuclear Information System (INIS)

    Friedland, Alexander

    2000-01-01

    We point out that for solar neutrino oscillations with the mass-squared difference of Δm 2 ∼10 -10 - 10 -9 eV 2 , i.e., in the so-called vacuum oscillation range, the solar matter effects are non-negligible, particularly for the low energy pp neutrinos. One consequence of this is that the values of the mixing angle θ and π/2-θ are not equivalent, making it necessary to consider the entire physical range of the mixing angle 0≤θ≤π/2 when determining the allowed values of the neutrino oscillation parameters. (c) 2000 The American Physical Society

  18. Temperature fluctuation effect on microstructural evolution of vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Hideo; Ochiai, Kenso; Yoshida, Naoaki [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1996-04-01

    To compare the damage structure of vanadium and it`s alloy by irradiation at a constant and fluctuating temperature, the microstructure of samples irradiated by heavy ion were observed by an electron microscope. Pure vanadium (99.9%) from China was used as samples. After preparing the samples for the electron microscope, they are covered with Zr and Ta film, vacuum sealed and annealed for 2h at 1323K. Then the samples were irradiated by 3 MeV Cu ion of 0.75-100 dpa at 473-873K. Temperature was changed from low to high (473K/673K, 473K/873K, 673K/873K). On the irradiation experiments at constant temperature, the density of dislocation decreased with increasing temperature, but, more than 773K, the density became very low and the needle precipitation grown to <100> and void were observed. On the irradiation experiment at 673K/873K, the density of number of precipitation and void were decreased. (S.Y.)

  19. Oil price fluctuations and Its effect on GDP growth

    OpenAIRE

    Gonzalez , Aaron; Nabiyev, Sherzod

    2009-01-01

    During the year of 2008, the world has experienced historically high oil prices reaching an all time high of 147 USD per barrel in midsummer. The extreme volatility of what is consider the number one source of energy reopened discussions about energy sustainability and the plausible effects of an oil shock in the global economy.   How reliable oil price is as an economic variable predicting fluctuations in GDP growth remains controversial. Several models have been developed by scholars target...

  20. Simulation Research of Magnetic Constriction Effect and Controlling by Axial Magnetic Field of Vacuum Arc

    Institute of Scientific and Technical Information of China (English)

    王立军; 贾申利; 史宗谦; 荣命哲

    2005-01-01

    Based on magnetohydrodynamic (MHD) model of vacuum arc, the computer simulation of vacuum arc was carried out in this paper. In the MHD model, mass conservation equation,momentum conservation equations, energy conservation equations, generalized ohm's law and Maxwell equation were considered. MHD equations were calculated by numerical method, and the distribution of vacuum arc plasma parameters and current density were obtained. Simulation results showed that the magnetic constriction effect of vacuum arc is primarily caused by the Hall effect. In addition, the inhibition of axial magnetic field (AMF) on constriction of vacuum arc was calculated and analyzed.

  1. The Effect of Quantum Fluctuations in Compact Star Observables

    Science.gov (United States)

    Pósfay, P.; Barnaföldi, G. G.; Jakovác, A.

    2018-05-01

    Astrophysical measurements regarding compact stars are just ahead of a big evolution jump, since the NICER experiment deployed on ISS on 2017 June 14. This will provide soon data that would enable the determination of compact star radius with less than 10% error. This can be further constrained by the new observation of gravitational waves originated from merging neutron stars, GW170817. This poses new challenges to nuclear models aiming to explain the structure of super dense nuclear matter found in neutron stars. Detailed studies of the QCD phase diagram show the importance of bosonic quantum fluctuations in the cold dense matter equation of state. Here we used a demonstrative model with one bosonic and one fermionic degree of freedom coupled by Yukawa coupling, we show the effect of bosonic quantum fluctuations on compact star observables such as mass, radius, and compactness. We have also calculated the difference in the value of compressibility which is caused by quantum fluctuations. The above-mentioned quantities are calculated in the mean field, one-loop, and in high order many loop approximation. The results show that the magnitude of these effects is in the range of 4-5%, which place it into the region where modern measurements may detect it. This forms a base for further investigations that how these results carry over to more complicated models.

  2. Thermal fluctuation effects far from the critical temperature

    International Nuclear Information System (INIS)

    Refai, T.F.

    1980-01-01

    We report the first measurements of thermal fluctuations in superconductors at temperatures far from the critical temperature T/sub c/ (T approx. 1/2 T/sub c/), and also the first measurements that use thermal fluctuations to probe the non-equilibrium dynamics of a superconductor. This is the first work that separately measures the fluctuations that cause a superconductor to switch to the dissipative state and those that cause it to switch back to the superconductor state. These unique measurements allowed: (1) The first measurement experimental confirmation of the theory of Langer, Ambegaokar, McCumber, and Halperin (LAMH) where T/sub c/ was not an adjustable parameter. This rigorous test of the theory was not previously possible because earlier measurements were carried out very near T/sub c/, where a change of many orders of magnitude of predicted effects occur if the assumed T/sub c/ changes a few millidegrees. Thus T/sub c/ in all previous work was always adjusted so as to get agreement with the theory. (2) The first verification of the LAMH model far from T/sub c/. (3) The first experimental confirmation of the relation between current and transition probability that was predicted in the LAMH model. (4) Confirmation that the Lamda model developed by Peters, Wolf, and Rachford (PWR) to explain the dynamics on the nonequilibrium region can be extended to explain fluctuation effects. This is based on an original phenomenological extension of the LAMH model that is developed in this work and on our data. (5) The most direct measurement to date of the nature of the decay of the dissipative region in a weak link. These measurements show that the region recovers exponentially in time as proposed in the Lamda model

  3. Minimizing the effect of exponential trends in detrended fluctuation analysis

    International Nuclear Information System (INIS)

    Xu Na; Shang Pengjian; Kamae, Santi

    2009-01-01

    The detrended fluctuation analysis (DFA) and its extensions (MF-DFA) have been used extensively to determine possible long-range correlations in time series. However, recent studies have reported the susceptibility of DFA to trends which give rise to spurious crossovers and prevent reliable estimation of the scaling exponents. In this report, a smoothing algorithm based on the discrete laplace transform (DFT) is proposed to minimize the effect of exponential trends and distortion in the log-log plots obtained by MF-DFA techniques. The effectiveness of the technique is demonstrated on monofractal and multifractal data corrupted with exponential trends.

  4. Polarization of the vacuum by a stochastic external field

    International Nuclear Information System (INIS)

    Krive, I.V.; Pastur, L.A.; Rozhavskii, A.S.

    1988-01-01

    The effect of disorder, realized in the form of a fluctuating extra mass term, on the bosonic vacuum and fermionic vacuum of models of quantum field theory is studied. A method is developed for calculating the mean effective potential in the stochastic external field. For a model of interacting scalar and fermion fields in (3+1)-dimensional space-time it is shown that random fluctuations of the mass lead to an increase of the equilibrium mean scalar field in the system

  5. Dirac vacuum: Acceleration and external-field effects

    International Nuclear Information System (INIS)

    Jauregui, R.; Torres, M.; Hacyan, S.

    1991-01-01

    The quantization of the massive spin-1/2 field in Rindler coordinates is considered, including the effects of a background magnetic field. We calculate the expectation values of conserved quantities such as the stress-energy tensor, current density, and spin distribution, as detected by an accelerated observer. The ratio of the energy and particle densities is given by a Fermi-Dirac distribution, but the spectrum of these quantities takes in general a complicated form that cannot be simply interpreted as a thermal spectrum. For the free-particle case the spectrum of the energy-stress tensor has a Fermi-Dirac form only in the massless limit. In the presence of the magnetic field the Dirac vacuum is magnetized and exhibits plasmalike properties

  6. Vacuum polarization effects in low-energy muonic atom collisions

    International Nuclear Information System (INIS)

    Melezhik, V.S.

    1995-01-01

    We estimate the vacuum polarization (VP) correction to the Coulomb interaction in collisions of muonic atoms. It is shown that the VP effect, amplified by the low-lying virtual state var-epsilon var-theta ∼10 eV, is of the order of ∼1--2 % in the S-wave cross sections for pμ+p collisions as var-epsilon ≤ var-epsilon var-theta . The VP amplitude becomes comparable to the anomalously small pure Coulomb amplitude for the singlet tμ+t scattering as var-epsilon →0 and near the Ramsauer-Townsend minima in the dμ+p and tμ+p scattering

  7. Effect of Vacuum Frying on Quality Attributes of Fruits

    NARCIS (Netherlands)

    Ayustaningwarno, Fitriyono; Dekker, Matthijs; Fogliano, Vincenzo; Verkerk, Ruud

    2018-01-01

    Vacuum frying of fruits enables frying at lower temperatures compared to atmospheric frying, thereby improving quality attributes of the fried product, such as oil content, texture, retention of nutrients, and color. Producing high-quality vacuum-fried fruit is a challenge, especially because of the

  8. Non-Euclidean Geometry, Nontrivial Topology and Quantum Vacuum Effects

    Directory of Open Access Journals (Sweden)

    Yurii A. Sitenko

    2018-01-01

    Full Text Available Space out of a topological defect of the Abrikosov–Nielsen–Olesen (ANO vortex type is locally flat but non-Euclidean. If a spinor field is quantized in such a space, then a variety of quantum effects are induced in the vacuum. On the basis of the continuum model for long-wavelength electronic excitations originating in the tight-binding approximation for the nearest-neighbor interaction of atoms in the crystal lattice, we consider quantum ground-state effects in Dirac materials with two-dimensional monolayer structures warped into nanocones by a disclination; the nonzero size of the disclination is taken into account, and a boundary condition at the edge of the disclination is chosen to ensure self-adjointness of the Dirac–Weyl Hamiltonian operator. We show that the quantum ground-state effects are independent of the disclination size, and we find circumstances in which they are independent of parameters of the boundary condition.

  9. Reparation effects of vacuum wound therapy in patients with diabetic foot syndrome.

    OpenAIRE

    Besedin, A. M.

    2015-01-01

    Vacuum Therapy (Vacuum-assisted closure, VAC) - a method of complex therapy which is used to improve the healing of both acute chronic wounds in patients with diabetic foot syndrome. Due to widespread introduction of this technique, unique cell, extracellular and general effects of its use in the treatment of patients with purulent-necrotic complications of diabetic foot syndrome, a technique of vacuum wound therapy has been successfully used in many surgical departments of Ukraine. Despite t...

  10. Limiter effects on scrape-off layer fluctuations and transport

    International Nuclear Information System (INIS)

    Thayer, D.R.; Diamond, P.H.; Wootton, A.J.

    1987-01-01

    Edge turbulence experiments indicate that radial particle flux increases as a function of radius up to the scrape-off layer (SOL), and that the Boltzman relation is violated. Resistivity gradient driven turbulence (RGDT) theory has been shown to track the radial dependence of the particle flux in the plasma edge closer than dissipative density gradient driven turbulence (DDGDT) theory. Also, the Boltzman relation is not invoked for RGDT while it is usually assumed for DDGDT. Consequently, RGDT is a more likely candidate for an edge turbulence model. However, Langmuir probe experiments indicate that the particle flux is reduced by as much as 50% in the SOL. Thus, since basic turbulence theories do not account for limiter effects, the primary focus of this study is to include such effects in a RGDT theory of the SOL. We present an analysis of SOL fluctuations using a rippling mode or RGDT calculation which incorporates the essential limiter boundary condition.(orig./GG)

  11. Effects of the quantum vacuum in particle physics and cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, Juri

    2014-11-26

    In this work we investigate numerous effects of virtual particles on processes relevant for particle physics and cosmology. A central question is, whether radiative spontaneous electroweak symmetry breaking can be combined with neutrino mass generation, we find that the answer is affirmative. We discuss the implication of the RSSB on the neutrino mass phenomenology and low-energy observables. Furthermore, by comparing the models to experimental data we find that several anomalies in the present observations favour particular scenarios over the pure Standard Model hypothesis. We are able to show, that the presence of sterile neutrinos with active-sterile mixing of order 10{sup -3} and masses in the TeV range leads to a reduced invisible decay width of the Z-boson and can bring the NuTeV observations in agreement with theoretical expectations. The models we discuss naturally incorporate long lived particles which can serve as dark matter candidates and we investigate this phenomenologically. We find that the combination of the requirements leads to interesting constraints on the model and parameter space. We find that loop induced electromagnetic moments for the neutral dark matter candidates, lead to interactions with charged particles. We use this and derive new constraints from existing XENON100 and LUX data. In addition we study how vacuum effects can backreact on a given geometry in electromagnetism and semiclassical gravity. We find that in the case of gravity the conformal set up plays a special role and indicate several ideas for further investigation of this topic.

  12. Nuclear quantum effects and hydrogen bond fluctuations in water

    Science.gov (United States)

    Ceriotti, Michele; Cuny, Jérôme; Parrinello, Michele; Manolopoulos, David E.

    2013-01-01

    The hydrogen bond (HB) is central to our understanding of the properties of water. However, despite intense theoretical and experimental study, it continues to hold some surprises. Here, we show from an analysis of ab initio simulations that take proper account of nuclear quantum effects that the hydrogen-bonded protons in liquid water experience significant excursions in the direction of the acceptor oxygen atoms. This generates a small but nonnegligible fraction of transient autoprotolysis events that are not seen in simulations with classical nuclei. These events are associated with major rearrangements of the electronic density, as revealed by an analysis of the computed Wannier centers and 1H chemical shifts. We also show that the quantum fluctuations exhibit significant correlations across neighboring HBs, consistent with an ephemeral shuttling of protons along water wires. We end by suggesting possible implications for our understanding of how perturbations (solvated ions, interfaces, and confinement) might affect the HB network in water. PMID:24014589

  13. Effect of Stochastic Charge Fluctuations on Dust Dynamics

    Science.gov (United States)

    Matthews, Lorin; Shotorban, Babak; Hyde, Truell

    2017-10-01

    The charging of particles in a plasma environment occurs through the collection of electrons and ions on the particle surface. Depending on the particle size and the plasma density, the standard deviation of the number of collected elementary charges, which fluctuates due to the randomness in times of collisions with electrons or ions, may be a significant fraction of the equilibrium charge. We use a discrete stochastic charging model to simulate the variations in charge across the dust surface as well as in time. The resultant asymmetric particle potentials, even for spherical grains, has a significant impact on the particle coagulation rate as well as the structure of the resulting aggregates. We compare the effects on particle collisions and growth in typical laboratory and astrophysical plasma environments. This work was supported by the National Science Foundation under Grant PHY-1414523.

  14. Effect of environment fluctuations on a Josephson current

    International Nuclear Information System (INIS)

    Galaktionov, A.V.

    2017-01-01

    Highlights: • Josephson current is influenced differently by environment fluctuations. • Two types of environment are studied: ohmic and resonant-mode one. • A crossover to a Josephson π-junction is possible for both of them. - Abstract: An influence of an electromagnetic environment on a Josephson current through a tunnel junction is studied with the aid of Ambegaokar-Eckern-Schön effective action. Two types of environment are investigated: one, characterized by a resonant mode, and an ohmic one. The crossover to a Josephson π-junction is possible for both of them. In addition the resonant-mode environment results in an increase of a Josephson current when the ratio of the doubled superconducting gap to the frequency of the mode is close to an integer number.

  15. Effect of wind fluctuating on self-starting aerodynamics characteristics of VAWT

    Institute of Scientific and Technical Information of China (English)

    朱建阳; 蒋林; 赵慧

    2016-01-01

    The present work deals with an investigation of the self-starting aerodynamic characteristics of VAWT under fluctuating wind. In contrast to the previous studies, the rotational speed of the turbine is not fixed, the rotation of the turbine is determined by the dynamic interaction between the fluctuating wind and turbine. A weak coupling method is developed to simulate the dynamic interaction between the fluctuating wind and passive rotation turbine, and the results show that if the fluctuating wind with appropriate fluctuation amplitude and frequency, the self-starting aerodynamic characteristics of VAWT will be enhanced. It is also found that compared with the fluctuation amplitude, the fluctuation frequency of the variation in wind velocity is shown to have a minor effect on the performance of the turbine. The analysis will provide straightforward physical insight into the self-starting aerodynamic characteristics of VAWT under fluctuating wind.

  16. Scrape-off layer-induced beam density fluctuations and their effect on beam emission spectroscopy

    Science.gov (United States)

    Moulton, D.; Marandet, Y.; Tamain, P.; Dif-Pradalier, G.

    2015-07-01

    A statistical model is presented to calculate the magnitude of beam density fluctuations generated by a turbulent scrape-off layer (SOL). It is shown that the SOL can induce neutral beam density fluctuations of a similar magnitude to the plasma density fluctuations in the core, potentially corrupting beam emission spectroscopy measurements. The degree of corruption is quantified by combining simulations of beam and plasma density fluctuations inside a simulated measurement window. A change in pitch angle from the separatrix to the measurement window is found to reduce the effect of beam fluctuations, whose largest effect is to significantly reduce the measured correlation time.

  17. Effects of vacuum compression therapy on skin microcirculation in patients suffering from lower limb ischaemia

    NARCIS (Netherlands)

    Ubbink, D. T.; van der Oord, B. M.; Sobotka, M. R.; Jacobs, M. J.

    2000-01-01

    We investigated the short-term effect of vacuum compression (VC) treatment on skin microcirculatory perfusion in the foot of patients with lower limb ischaemia and healthy controls. Ten patients with intermittent claudication or rest pain and 5 healthy controls underwent vacuum-compression treatment

  18. Effects of vacuum and controlled atmosphere treatments on insect mortality and lettuce quality.

    Science.gov (United States)

    Liu, Yong-Biao

    2003-08-01

    Laboratory studies were conducted to determine the effects of vacuum and controlled atmosphere on mortality of aphids, Nasonovia ribisnigri (Mosley) and Macrosiphum euphorbiae (Thomas), and leafminer, Liriomyza langei Frick, and on the visual quality of iceberg lettuce at three different temperatures. Vacuum at 50 mbar and controlled atmosphere with 6% CO2 were effective in controlling aphids and leafminer larvae. Complete control of N. ribisnigri and M. euphorbiae was achieved with vacuum treatments and 6% CO2 CA treatments at 5 degrees C in 4 d. Mortality was >96% when leafminer larvae were treated with vacuum and 6% CO2 CA treatments for 4 d. However, leafminer pupae were more tolerant to the treatments and highest mortality was close to 60% in 4 d with CO2 under vacuum. None of the treatments had negative effects on visual quality of iceberg lettuce. Results from this study are encouraging and warrant further and large-scale research.

  19. Vacuum Technology

    Energy Technology Data Exchange (ETDEWEB)

    Biltoft, P J

    2004-10-15

    The environmental condition called vacuum is created any time the pressure of a gas is reduced compared to atmospheric pressure. On earth we typically create a vacuum by connecting a pump capable of moving gas to a relatively leak free vessel. Through operation of the gas pump the number of gas molecules per unit volume is decreased within the vessel. As soon as one creates a vacuum natural forces (in this case entropy) work to restore equilibrium pressure; the practical effect of this is that gas molecules attempt to enter the evacuated space by any means possible. It is useful to think of vacuum in terms of a gas at a pressure below atmospheric pressure. In even the best vacuum vessels ever created there are approximately 3,500,000 molecules of gas per cubic meter of volume remaining inside the vessel. The lowest pressure environment known is in interstellar space where there are approximately four molecules of gas per cubic meter. Researchers are currently developing vacuum technology components (pumps, gauges, valves, etc.) using micro electro mechanical systems (MEMS) technology. Miniature vacuum components and systems will open the possibility for significant savings in energy cost and will open the doors to advances in electronics, manufacturing and semiconductor fabrication. In conclusion, an understanding of the basic principles of vacuum technology as presented in this summary is essential for the successful execution of all projects that involve vacuum technology. Using the principles described above, a practitioner of vacuum technology can design a vacuum system that will achieve the project requirements.

  20. Size effects in many-valley fluctuations in semiconductors

    International Nuclear Information System (INIS)

    Sokolov, V.N.; Kochelap, V.A.

    1995-08-01

    We present the results of theoretical investigations of nonhomogeneous fluctuations in submicron active regions of many-valley semiconductors with equivalent valleys(Ge, Si-type), where the dimension 2d of the region is comparable to or less than the intervalley diffusion relaxation length L iv . It is shown that for arbitrary orientations of the valley axes (the crystal axes) with respect to lateral sample surfaces, the fluctuation spectra depend on the bias voltage applied to the layer in the region of weak nonheating electric fields. The new physical phenomenon is reported: the fluctuation spectra depend on the sample thickness, with 2d iv the suppression of fluctuations arises for fluctuation frequencies ω -1 iv , τ -1 iv is the characteristic intervalley relaxation time. (author). 43 refs, 5 figs

  1. A theology of matter. The strong interaction at strong resonance at the meeting point of I and not-I. Conjectures about oscillating strings and fluctuating vacuum energy; Eine Theologie der Materie. Die starke Wechselwirkung bei starker Resonanz am Begegnungs-Ort von Ich und Nicht-Ich. Mutmassungen ueber oszillierende Strings und fluktuierende Vakuum-Energie

    Energy Technology Data Exchange (ETDEWEB)

    Boes, Roderick H.

    2011-07-01

    This book shows that matter and consciousness are intertwined and mutually produce. Quantum vacuum fluctuations ensure that the latent energy of each event is present as zero-point energy simultaneously at all points of the cosmos.

  2. Effect of irradiation on stored vacuum packaged Wiltshire bacon

    International Nuclear Information System (INIS)

    Dempster, J.F.; Halls, N.A.

    1988-01-01

    Wiltshire cured 'middle-cut' bacon (NaCl, 4.8%; 40 mg/kg NO 2 ; 53 mg/kg NO 3 ) was boned, sliced and vacuum packaged. It was irradiated (25 kGy: 10 kGy) and stored aerobically (5 0 : 15 0 ). At weekly intervals the bacon was evaluated bacteriologically and organoleptically (appearance, odour, colour of lean and fat) against unirradiated (control) samples). Results indicated that irradiation (10 kGy) did not permanently inhibit bacterial growth. After initial reductions in count of 0.99 g -1 (15 0 C) and log 3.61 g -1 (5 0 C), maximum numbers were reached in 28 days at 15 0 C (log 10.32 g -1 ) and in 35 days at 5 0 C (log 8.05 g -1 ). However viability was significantly affected by 25 kGy irradiation: final numbers reached being log 2.22 g -1 (15 0 C) at 35 days and log 3.38 g -1 (5 0 C) at 42 days. Appearance and colour (fat and lean) were not significantly impaired by irradiation. However the interaction of storage temperature (5 0 :15 0 C), irradiation (10 kGy: 25 kGy): duration of storage (42 days) and initial count (log 7.24 g -1 ) had pronounced adverse effects on odour judgements. Evaluation of odour changes in bacon due to irradiation require further investigation. This is especially so since it is often possible to detect odour changes in raw meat after doses as low as 0.5 kGy (Coleby 1959). (author)

  3. The greenhouse effect and natural fluctuations of the climate

    International Nuclear Information System (INIS)

    Schoenwiese, C.D.

    1993-01-01

    There is a straight line connecting the first estimate in 1896 of worldwide climate changes due to the increasing use of fossil sources of energy with the Climate Convention of the United Nations at the 1992 Environmental Summit. Extensive model calculations exist of the 'greenhouse effect', in which the lower atmosphere is heated by manmade emissions of trace gases affecting the climate. However, the anticipated changes are not restricted to the temperature of the air; they affect the climate as a whole worldwide. As a consequence, the German Federal Government, in addition to its ban on CFCs, plans to reduce manmade carbon dioxide emissions by 25 or 30% by 2005. Natural fluctuations of the climate compete with the greenhouse effect: Volcanic and solar effects, but also random variations within the complicated interactions in the climatic system (atmosphere - oceans - ice regions - biosphere - land surface). Mathematical and statistical analyses of the superposition of such climatic mechanisms, which are based on data from observations, result in a risk analysis at a high level of probability. (orig.) [de

  4. Transparent conducting film: Effect of vacuum filtration of carbon ...

    Indian Academy of Sciences (India)

    Administrator

    mechanical approach proposed in our recent work was deemed suitable to enhance optical and electrical ... advantages of using CNT for TC films including: (i) The ... 2006). (ii) Use longer CNT to reduce the number of .... layer with 1-hour sonication in oleum, and (c) vacuum-filtered MWNT layer with 4 h sonication in oleum.

  5. Fluctuations and the nuclear Meissner effect in rapidly rotating nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Canto, L F; Ring, P; Rasmussen, J O

    1985-10-24

    The phase transition from a superfluid system to a normal fluid system in nuclei under the influence of a strong Coriolis field is investigated by the generator coordinate method (GCM). The strange behavior of the experimental moments of inertia in the nucleus WYHf is well reproduced in this theory. The pairing collapse of the neutrons, however, is completely washed out by the fluctuations. It is found that the fluctuations of the orientation in gauge space, taken into account by number projection before the variation play the most important role. Fluctuations connected with the virtual admixture of pairing vibrations add only small corrections. (orig.).

  6. Field-theoretic approach to fluctuation effects in neural networks

    International Nuclear Information System (INIS)

    Buice, Michael A.; Cowan, Jack D.

    2007-01-01

    A well-defined stochastic theory for neural activity, which permits the calculation of arbitrary statistical moments and equations governing them, is a potentially valuable tool for theoretical neuroscience. We produce such a theory by analyzing the dynamics of neural activity using field theoretic methods for nonequilibrium statistical processes. Assuming that neural network activity is Markovian, we construct the effective spike model, which describes both neural fluctuations and response. This analysis leads to a systematic expansion of corrections to mean field theory, which for the effective spike model is a simple version of the Wilson-Cowan equation. We argue that neural activity governed by this model exhibits a dynamical phase transition which is in the universality class of directed percolation. More general models (which may incorporate refractoriness) can exhibit other universality classes, such as dynamic isotropic percolation. Because of the extremely high connectivity in typical networks, it is expected that higher-order terms in the systematic expansion are small for experimentally accessible measurements, and thus, consistent with measurements in neocortical slice preparations, we expect mean field exponents for the transition. We provide a quantitative criterion for the relative magnitude of each term in the systematic expansion, analogous to the Ginsburg criterion. Experimental identification of dynamic universality classes in vivo is an outstanding and important question for neuroscience

  7. Functional renormalization group study of fluctuation effects in fermionic superfluids

    Energy Technology Data Exchange (ETDEWEB)

    Eberlein, Andreas

    2013-03-22

    This thesis is concerned with ground state properties of two-dimensional fermionic superfluids. In such systems, fluctuation effects are particularly strong and lead for example to a renormalization of the order parameter and to infrared singularities. In the first part of this thesis, the fermionic two-particle vertex is analysed and the fermionic renormalization group is used to derive flow equations for a decomposition of the vertex in charge, magnetic and pairing channels. In the second part, the channel-decomposition scheme is applied to various model systems. In the superfluid state, the fermionic two-particle vertex develops rich and singular dependences on momentum and frequency. After simplifying its structure by exploiting symmetries, a parametrization of the vertex in terms of boson-exchange interactions in the particle-hole and particle-particle channels is formulated, which provides an efficient description of the singular momentum and frequency dependences. Based on this decomposition of the vertex, flow equations for the effective interactions are derived on one- and two-loop level, extending existing channel-decomposition schemes to (i) the description of symmetry breaking in the Cooper channel and (ii) the inclusion of those two-loop renormalization contributions to the vertex that are neglected in the Katanin scheme. In the second part, the superfluid ground state of various model systems is studied using the channel-decomposition scheme for the vertex and the flow equations. A reduced model with interactions in the pairing and forward scattering channels is solved exactly, yielding insights into the singularity structure of the vertex. For the attractive Hubbard model at weak coupling, the momentum and frequency dependence of the two-particle vertex and the frequency dependence of the self-energy are determined on one- and two-loop level. Results for the suppression of the superfluid gap by fluctuations are in good agreement with the literature

  8. Effects of limited spatial resolution on fluctuation measurements (invited)

    International Nuclear Information System (INIS)

    Bravenec, R.V.; Wootton, A.J.

    1995-01-01

    The finite sample volumes of fluctuation diagnostics distort the measurements not only by averaging the gross fluctuation parameters over the sample volumes, but more importantly (except for collective scattering), by attenuating the shorter wavelength components. In this work, the response of various sample volume sizes and orientations to a model fluctuation power spectrum S(k,ω) are examined. The model spectrum is fashioned after observations by far-infrared scattering on TEXT. The sample-volume extent in the direction of propagation of the turbulence is shown to be the most critical---not only does it reduce the measured fluctuation amplitude and increase the correlation length (as does an extent perpendicular to the propagation direction), but it also reduces the measured mean frequency and increases the apparent average phase velocity of the fluctuations. The differing sizes, shapes, and orientations of the sample volumes among fluctuation diagnostics, as well as deliberate variations within a single diagnostic, provide information on the form of the underlying turbulence and can be exploited to refine the model

  9. Effects of limited spatial resolution on fluctuation measurements

    International Nuclear Information System (INIS)

    Bravenec, R.V.; Wootton, A.J.

    1994-01-01

    The finite sample volumes of fluctuation diagnostics distort the measurements not only by averaging the gross fluctuation parameters over the sample volumes, but more importantly (except for collective scattering), by attenuating the shorter wavelength components. In this work the response of various sample volume sizes and orientations to a model fluctuation power spectrum S(k,ω) are examined. The model spectrum is fashioned after observations by far-infrared scattering on TEXT. The sample-volume extent in the direction of propagation of the turbulence is shown to be the most critical - not only does it reduce the measured fluctuation amplitude and correlation length (as does an extent perpendicular to the propagation direction), but also reduces the measured mean frequency and increases the apparent average phase velocity of the fluctuations. The differing sizes, shapes, and orientations of the sample volumes among fluctuation diagnostics, as well as deliberate variations within a single diagnostic, provide information on the form of the underlying turbulence and can be exploited to refine the model

  10. Interactions between electrons, mesoscopic Josephson effect and asymmetric current fluctuations

    Science.gov (United States)

    Huard, B.

    2006-07-01

    This article discusses three experiments on the properties of electronic transport at the mesoscopic scale. The first one allowed to measure the energy exchange rate between electrons in a metal contaminated by a very weak concentration of magnetic impurities. The role played by magnetic impurities in the Kondo regime on those energy exchanges is quantitatively investigated, and the global measured exchange rate is larger than expected. The second experiment is a measurement of the current-phase relation in a system made of two superconductors linked through a single atom. We thus provide quantitative support for the recent description of the mesoscopic Josephson effect. The last experiment is a measurement of the asymmetry of the current fluctuations in a mesoscopic conductor, using a Josephson junction as a threshold detector. Cet ouvrage décrit trois expériences portant sur les propriétés du transport électronique à l'échelle mésoscopique. La première a permis de mesurer le taux d'échange d'énergie entre électrons dans un métal contenant une très faible concentration d'impuretés magnétiques. Nous avons validé la description quantitative du rôle des impuretés magnétiques dans le régime Kondo sur ces échanges énergétiques et aussi montré que le taux global d'échange est plus fort que prévu. La seconde expérience est une mesure de la relation courant-phase dans un système constitué de deux supraconducteurs couplés par un seul atome. Elle nous a permis de conforter quantitativement la récente description de l'effet Josephson mésoscopique. La dernière expérience est unemesure de l'asymétrie des fluctuations du courant dans un conducteur mésoscopique en utilisant une Jonction Josephson comme détecteur de seuil.

  11. Impact of quantum entanglement on spectrum of cosmological fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, Sugumi, E-mail: sugumi.kanno@uct.ac.za [Laboratory for Quantum Gravity and Strings and Astrophysics, Cosmology and Gravity Center, Department of Mathematics and Applied Mathematics, University of Cape Town, Private Bag, Rondebosch 7701 (South Africa)

    2014-07-01

    We investigate the effect of entanglement between two causally separated open charts in de Sitter space on the spectrum of vacuum fluctuations. We consider a free massive scalar field, and construct the reduced density matrix by tracing out the vacuum state for one of the open charts, as recently derived by Maldacena and Pimentel. We formulate the mean-square vacuum fluctuations by using the reduced density matrix and show that the scale invariant spectrum of massless scalar field is realized on small scales. On the other hand, we find that the quantum entanglement affects the shape of the spectrum on large scales comparable to or greater than the curvature radius.

  12. Cooling mechanical motion via vacuum effect of an ensemble of quantum emitters.

    Science.gov (United States)

    Nie, Wenjie; Chen, Aixi; Lan, Yueheng

    2015-11-30

    We design a hybrid optomechanical setup, in which an ensemble of quantum emitters is coupled with a movable mirror through vacuum interaction. The optical cavity is driven along with the quantum emitters and therefore the coupling between the cavity field and the ensemble determines the dynamics of the coupled system. In particular, we investigated the influence of the vacuum coupling strength on the effective frequency and the effective damping rate of the movable mirror, which shows that the vacuum interaction enhances greatly the effective damping rate. Further, the cooling characteristics of the mechanical resonator is analyzed in detail by counting the effective phonon number in the mirror's motion. It is found that the ground-state cooling of the mechanical motion can be approached in the bad cavity limit when the vacuum coupling is included. The dependence of the cooling of the mechanical motion on the parameters of the cavity and the quantum emitter is investigated in detail numerically.

  13. The self-energy of a heavy quark in the gluonic vacuum and the effective mass

    International Nuclear Information System (INIS)

    Ishizuka, W.; Kikuchi, Y.

    1983-01-01

    We calculate, be use of the multipole expansion, the self-energy of the heavy quark in the gluonic vacuum from which the momentum dependent effective mass is derived. A phenomenological consequence is discussed also. (orig.)

  14. Microbial effect of steam vacuum pasteurisation implemented after slaughtering and dressing of sheep and lamb.

    Science.gov (United States)

    Hassan, Ammar Ali; Skjerve, Eystein; Bergh, Claus; Nesbakken, Truls

    2015-01-01

    The main objective of the study was to assess the effect of steam vacuum pasteurisation on carcass contamination with focus on Escherichia coli, Enterobacteriaceae and total plate count (TPC). Additionally, the effect of an additional tryptone soy agar (TSA) step for resuscitation of Enterobacteriaceae after steam vacuum pasteurisation was investigated. Steam vacuum pasteurisation was applied at a temperature of >82°C for a duration of 10s on sheep and lamb carcasses (n=120). Samples were taken immediately: i) after trimming just before the use of steam vacuum and ii) after use of steam vacuum. Nordic Committee on Food Analysis methods were used in microbial analyses. The differences in log reduction were found significant for all of the three microorganisms (psteam vacuum pasteurisation was higher in samples where TSA+violet red bile glucose agar (VRBGA) was used compared to samples where only VRBGA was used (pSteam vacuum pasteurisation was found efficient in reducing the total count, read as TPC, as well as the level of E. coli and Enterobacteriaceae. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Local effects of the quantum vacuum in Lorentz-violating electrodynamics

    Science.gov (United States)

    Martín-Ruiz, A.; Escobar, C. A.

    2017-02-01

    The Casimir effect is one of the most remarkable consequences of the nonzero vacuum energy predicted by quantum field theory. In this paper we use a local approach to study the Lorentz violation effects of the minimal standard model extension on the Casimir force between two parallel conducting plates in the vacuum. Using a perturbative method similar to that used for obtaining the Born series for the scattering amplitudes in quantum mechanics, we compute, at leading order in the Lorentz-violating coefficients, the relevant Green's function which satisfies given boundary conditions. The standard point-splitting technique allow us to express the vacuum expectation value of the stress-energy tensor in terms of the Green's function. We discuss its structure in the region between the plates. We compute the renormalized vacuum stress, which is obtained as the difference between the vacuum stress in the presence of the plates and that of the vacuum. The Casimir force is evaluated in an analytical fashion by two methods: by differentiating the renormalized global energy density and by computing the normal-normal component of the renormalized vacuum stress. We compute the local Casimir energy, which is found to diverge as approaching the plates, and we demonstrate that it does not contribute to the observable force.

  16. The effect of plasma fluctuations on parallel transport parameters in the SOL

    DEFF Research Database (Denmark)

    Havlíčková, E.; Fundamenski, W.; Naulin, Volker

    2011-01-01

    The effect of plasma fluctuations due to turbulence at the outboard midplane on parallel transport properties is investigated. Time-dependent fluctuating signals at different radial locations are used to study the effect of signal statistics. Further, a computational analysis of parallel transport...... to a comparison of steady-state and time-dependent modelling....

  17. Vacuum effect on the etch induction time and registration sensitivity of polymer track detectors

    International Nuclear Information System (INIS)

    Csige, I.; Hunyadi, I.; Somogyi, G.

    1988-01-01

    The effect of a vacuum on etch induction time and track etch rate ratio of some polymer track detectors was studied systematically with alpha particles of different energies. It was found that the etch induction time increases, and the track etch rate ratio decreases, drastically when the detectors were irradiated in a vacuum and also kept in a vacuum for a few hours before and for a few minutes after the irradiation. These times proved to be characteristic for the outgassing of oxygen from the sheets and the stabilization of latent tracks, respectively. The role of oxygen in latent track formation is discussed. We have found that the vacuum effect is most significant near the surface. Its diminution with depth depends on the time of outgassing in accordance with the time variation of the dissolved oxygen concentration profile inside the sheets. (author)

  18. Vacuum effect on the etch induction time and registration sensitivity of polymer track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Csige, I.; Hunyadi, I.; Somogyi, G. (Magyar Tudomanyos Akademia, Debrecen (Hungary). Atommag Kutato Intezete); Fujii, M. (Institute of Space and Astronautical Science, Sagamihara (Japan))

    1988-01-01

    The effect of a vacuum on etch induction time and track etch rate ratio of some polymer track detectors was studied systematically with alpha particles of different energies. It was found that the etch induction time increases, and the track etch rate ratio decreases, drastically when the detectors were irradiated in a vacuum and also kept in a vacuum for a few hours before and for a few minutes after the irradiation. These times proved to be characteristic for the outgassing of oxygen from the sheets and the stabilization of latent tracks, respectively. The role of oxygen in latent track formation is discussed. We have found that the vacuum effect is most significant near the surface. Its diminution with depth depends on the time of outgassing in accordance with the time variation of the dissolved oxygen concentration profile inside the sheets. (author).

  19. Fluctuation effects on bubble growth in hot nuclear matter

    International Nuclear Information System (INIS)

    Santiago, A.J.; Chung, K.C.

    1991-01-01

    The evolution of bubbles with arbitrary density in an infinite nuclear system is studied in a simplified treatment. Kinetic pressure fluctuations on the bubble surface are considered. The critical radius, evolution time and probability for bubble expansion are shown to depend significantly on the initial bubble density. (author)

  20. Atmospheres and spectra of strongly magnetized neutron stars - II. The effect of vacuum polarization

    Science.gov (United States)

    Ho, Wynn C. G.; Lai, Dong

    2003-01-01

    We study the effect of vacuum polarization on the atmosphere structure and radiation spectra of neutron stars with surface magnetic fields B= 1014-1015 G, as appropriate for magnetars. Vacuum polarization modifies the dielectric property of the medium and gives rise to a resonance feature in the opacity; this feature is narrow and occurs at a photon energy that depends on the plasma density. Vacuum polarization can also induce resonant conversion of photon modes via a mechanism analogous to the Mikheyev-Smirnov-Wolfenstein (MSW) mechanism for neutrino oscillation. We construct atmosphere models in radiative equilibrium with an effective temperature of a few ×106 K by solving the full radiative transfer equations for both polarization modes in a fully ionized hydrogen plasma. We discuss the subtleties in treating the vacuum polarization effects in the atmosphere models and present approximate solutions to the radiative transfer problem which bracket the true answer. We show from both analytic considerations and numerical calculations that vacuum polarization produces a broad depression in the X-ray flux at high energies (a few keV <~E<~ a few tens of keV) as compared to models without vacuum polarization; this arises from the density dependence of the vacuum resonance feature and the large density gradient present in the atmosphere. Thus the vacuum polarization effect softens the high-energy tail of the thermal spectrum, although the atmospheric emission is still harder than the blackbody spectrum because of the non-grey opacities. We also show that the depression of continuum flux strongly suppresses the equivalent width of the ion cyclotron line and therefore makes the line more difficult to observe.

  1. Model of cancer growth affected by irradiation. Effect of fluctuating intensity of the dose

    International Nuclear Information System (INIS)

    Gudowska-Nowak, E.

    1984-01-01

    The behaviour of a biological model system which describes the growth of a cancer cell population in the presence of external irradiation is studied. The effect of randomly fluctuating source of radiation is analysed and its influence on cancer cell extinction is presented. The main stress is put on the biological significance of random fluctuations which seem to favour rejection of a tumor. (author)

  2. Thermal crackling: study of the mechanical effects of quick temperature fluctuations on metallic surfaces

    International Nuclear Information System (INIS)

    Pradel, P.

    1984-05-01

    After a brief overview of the thermohydraulical conditions of liquid sodium leading to important temperature fluctuations near the metallic surfaces, the author examines the transfer modes of these fluctuations in the structure thickness and the long term mechanical effects. Dimensioning models based on thermal and metallurgical properties are under study for structures subject to such sodium loads [fr

  3. On the possible effects of gluon number fluctuations on {gamma}{gamma} collisions at high energies

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, V. P.; De Santana Amaral, J. T. [Instituto de Fisica e Matematica, Universidade Federal de Pelotas, Caixa Postal 354, 96010-900, Pelotas, RS (Brazil)

    2013-03-25

    We investigate the effects of the fluctuations on the total {gamma}{gamma}, {gamma}*{gamma}* cross sections and the real photon structure function F{sup {gamma}}{sub 2}(x,Q{sup 2}), considering a saturation phenomenological model for the dipole-dipole cross section and scattering amplitude with fluctuations included.

  4. The effect of climate fluctuation on chimpanzee birth sex ratio.

    Directory of Open Access Journals (Sweden)

    Hjalmar S Kühl

    Full Text Available Climate and weather conditions, such as the North Atlantic Oscillation, precipitation and temperature influence the birth sex ratio (BSR of various higher latitude species, including deer, elephant seals or northern human populations. Although, tropical regions show only little variation in temperature, climate and weather conditions can fluctuate with consequences for phenology and food resource availability. Here, we evaluate, whether the BSR of chimpanzees, inhabiting African tropical forests, is affected by climate fluctuations as well. Additionally, we evaluate, if variation in consumption of a key food resource with high nutritional value, Coula edulis nuts, is linked to both climate fluctuations and variation in BSR. We use long-term data from two study groups located in Taï National Park, Côte d'Ivoire to assess the influence of local weather conditions and the global climate driver El Niño Southern Oscillation (ENSO on offspring sex. Côte d'Ivoire has experienced considerable climate variation over the last decades, with increasing temperature and declining precipitation. For both groups we find very similar time windows around the month of conception, in which offspring sex is well predicted by ENSO, with more males following low ENSO values, corresponding to periods of high rainfall. Furthermore, we find that the time spent cracking and feeding on Coula nuts is strongly influenced by climate conditions. Although, some of our analysis suggest that a higher proportion of males is born after periods with higher nut consumption frequency, we cannot conclude decisively at this point that nut consumption may influence shifts in BSR. All results combined suggest that also chimpanzees may experience climate related shifts in offspring sex ratios as response to climate fluctuation.

  5. Neutrino propagation in a fluctuating sun

    International Nuclear Information System (INIS)

    Burgess, C.P.; Michaud, D.

    1997-01-01

    We adapt to neutrino physics a general formulation for particle propagation in fluctuating media, initially developed for applications to electromagnetism and neutron optics. In leading approximation this formalism leads to the usual MSW effective Hamiltonian governing neutrino propagation through a medium. Next-to-leading contributions describe deviations from this description, which arise due to neutrino interactions with fluctuations in the medium. We compute these corrections for two types of fluctuations: (i) microscopic thermal fluctuations and (ii) macroscopic fluctuations in the medium s density. While the first of these reproduces standard estimates, which are negligible for applications to solar neutrinos, we find that the second can be quite large, since it grows in size with the correlation length of the fluctuation. We consider two models in some detail. For fluctuations whose correlations extend only over a local region in space of length l, appreciable effects for MSW oscillations arise if (δn/n) 2 l approx-gt 100m or so. Alternatively, a crude model of helioseismic p-waves gives appreciable effects only when (δn/n)approx-gt 1%. In general the dominant effect is to diminish the quality of the resonance, making the suppression of the 7 Be neutrinos a good experimental probe of fluctuations deep within the sun. Fluctuations can also provide a new mechanism for reducing the solar neutrino flux, giving an energy-independent suppression factor of 1/2 away from the resonant region, even for small vacuum mixing angles. copyright 1997 Academic Press, Inc

  6. Plasma Fluctuation Studies in the TCV Tokamak: Modeling of Shaping Effects and Advanced Diagnostic Development

    International Nuclear Information System (INIS)

    Marinoni, A.

    2009-10-01

    therefore also well suited to investigate inhomogeneous spatial regions, where the need for an excellent spatial resolution is greatest. Additionally, it was also designed as translatable to broaden the region of study, which can extend up to the magnetic axis, in selected configurations. The translatable design combined with the flexibility of TCV in terms of plasma positioning in the vacuum vessel allows the phase contrast system to measure fluctuations across virtually the whole plasma minor radius. The diagnostic is sensitive both to radial and poloidal wave numbers, depending on the configuration. A parallel project to the development and installation of the phase contrast imaging system was the installation of a prototype Doppler reflectometer operating in a homodyne configuration, both in X and in O mode polarization. The reflectometer was operated parasitically to assess its performance which proved to be excellent; it is now routinely available on TCV. The theoretical part of the thesis consisted of extensive modeling of the effect of plasma shape, in particular triangularity, on turbulent transport by means of linear and nonlinear gyrokinetic simulations. This was motivated by experiments on TCV that had shown a dramatic improvement in confinement, up to a factor of two, in inverting the sign of the triangularity from positive to negative. Negative triangularity was indeed found to have a stabilizing influence on ion scale instabilities, specifically on the so called trapped electron mode (TEM). Simulations were carried out on actual TCV shots and the variation of the heat flux with triangularity calculated by the nonlinear simulations is in fair agreement with the experimental results. Linear simulations and a simple analytical model explain, in agreement with nonlinear runs, the resulting stabilization as a result of a rather complex modification of the toroidal precessional drift of trapped particles exerted by negative triangularity. (author)

  7. The effect of longitudinal fluctuations in (3+1)D viscous hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Long-Gang; Karpenko, Yuri [FIAS, Frankfurt (Germany); Petersen, Hannah [FIAS, Frankfurt (Germany); ITP, Goethe University, Frankfurt (Germany); GSI, Darmstadt (Germany); Huovinen, Pasi [ITP, University of Wroclaw (Poland); Wang, Xin-Nian [CCNU, Wuhan (China); LBNL, Berkeley (United States)

    2016-07-01

    The energy density fluctuations of the quark gluon plasma (QGP) in the transverse plane are studied in detail and found to be important to explain the high order harmonic flow v{sub n} at RHIC and LHC. However, the energy density fluctuations along longitudinal direction (space-time rapidity η{sub s}) have not been fully investigated yet, even though they should exist as well. Previous studies show that the longitudinal fluctuations strongly depend on the initial entropy deposition mechanisms. In this work AMPT initial conditions are used where HIJING introduces longitudinal fluctuations originating from the asymmetry between forward and backward going participants, string length fluctuations and finite number of partons at different collision energies. The longitudinal fluctuations have been found to be responsible for the de-correlation of anisotropic flow and twist of event planes along rapidity. We study the effect of longitudinal fluctuations on the QGP expansion in both transverse and longitudinal direction within CLVisc, a (3+1)D viscous hydrodynamic code parallelized on GPU using OpenCL, to check whether the anisotropic flow is affected by longitudinal fluctuations and to determine appropriate shear viscosity over entropy density coefficients η/s in comparison with experiments at RHIC and LHC.

  8. Giant fluctuations and structural effects in a flocking epithelium

    Science.gov (United States)

    Giavazzi, Fabio; Malinverno, Chiara; Corallino, Salvatore; Ginelli, Francesco; Scita, Giorgio; Cerbino, Roberto

    2017-09-01

    Epithelial cells cultured in a monolayer are very motile in isolation but reach a near-jammed state when mitotic division increases their number above a critical threshold. We have recently shown that a monolayer can be reawakened by over-expression of a single protein, RAB5A, a master regulator of endocytosis. This reawakening of motility was explained in terms of a flocking transition that promotes the emergence of a large-scale collective migratory pattern. Here we focus on the impact of this reawakening on the structural properties of the monolayer. We find that the unjammed monolayer is characterised by a fluidisation at the single cell level, and by enhanced non-equilibrium large-scale number fluctuations at a larger length scale. Also, with the help of numerical simulations, we trace back the origin of these fluctuations to the self-propelled active nature of the constituents, and to the existence of a local alignment mechanism, leading to the spontaneous breaking of the orientational symmetry.

  9. Giant fluctuations and structural effects in a flocking epithelium

    International Nuclear Information System (INIS)

    Giavazzi, Fabio; Cerbino, Roberto; Malinverno, Chiara; Corallino, Salvatore; Scita, Giorgio; Ginelli, Francesco

    2017-01-01

    Epithelial cells cultured in a monolayer are very motile in isolation but reach a near-jammed state when mitotic division increases their number above a critical threshold. We have recently shown that a monolayer can be reawakened by over-expression of a single protein, RAB5A, a master regulator of endocytosis. This reawakening of motility was explained in terms of a flocking transition that promotes the emergence of a large-scale collective migratory pattern. Here we focus on the impact of this reawakening on the structural properties of the monolayer. We find that the unjammed monolayer is characterised by a fluidisation at the single cell level, and by enhanced non-equilibrium large-scale number fluctuations at a larger length scale. Also, with the help of numerical simulations, we trace back the origin of these fluctuations to the self-propelled active nature of the constituents, and to the existence of a local alignment mechanism, leading to the spontaneous breaking of the orientational symmetry. (paper)

  10. Effects of thermal fluctuations on the thermodynamics of modified Hayward black hole

    Energy Technology Data Exchange (ETDEWEB)

    Pourhassan, Behnam [Damghan University, School of Physics, Damghan (Iran, Islamic Republic of); Faizal, Mir [University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada); Debnath, Ujjal [Indian Institute of Engineering Science and Technology, Shibpur, Department of Mathematics, Howrah (India)

    2016-03-15

    In this work, we analyze the effects of thermal fluctuations on the thermodynamics of a modified Hayward black hole. These thermal fluctuations will produce correction terms for various thermodynamical quantities like entropy, pressure, internal energy, and specific heats. We also investigate the effect of these correction terms on the first law of thermodynamics. Finally, we study the phase transition for the modified Hayward black hole. It is demonstrated that the modified Hayward black hole is stable even after the thermal fluctuations are taken into account, as long as the event horizon is larger than a certain critical value. (orig.)

  11. Study of energy fluctuation effect on the statistical mechanics of equilibrium systems

    International Nuclear Information System (INIS)

    Lysogorskiy, Yu V; Wang, Q A; Tayurskii, D A

    2012-01-01

    This work is devoted to the modeling of energy fluctuation effect on the behavior of small classical thermodynamic systems. It is known that when an equilibrium system gets smaller and smaller, one of the major quantities that becomes more and more uncertain is its internal energy. These increasing fluctuations can considerably modify the original statistics. The present model considers the effect of such energy fluctuations and is based on an overlapping between the Boltzmann-Gibbs statistics and the statistics of the fluctuation. Within this o verlap statistics , we studied the effects of several types of energy fluctuations on the probability distribution, internal energy and heat capacity. It was shown that the fluctuations can considerably change the temperature dependence of internal energy and heat capacity in the low energy range and at low temperatures. Particularly, it was found that, due to the lower energy limit of the systems, the fluctuations reduce the probability for the low energy states close to the lowest energy and increase the total average energy. This energy increasing is larger for lower temperatures, making negative heat capacity possible for this case.

  12. Nonperturbative Dynamical Casimir Effect in Optomechanical Systems: Vacuum Casimir-Rabi Splittings

    Directory of Open Access Journals (Sweden)

    Vincenzo Macrì

    2018-02-01

    Full Text Available We study the dynamical Casimir effect using a fully quantum-mechanical description of both the cavity field and the oscillating mirror. We do not linearize the dynamics, nor do we adopt any parametric or perturbative approximation. By numerically diagonalizing the full optomechanical Hamiltonian, we show that the resonant generation of photons from the vacuum is determined by a ladder of mirror-field vacuum Rabi splittings. We find that vacuum emission can originate from the free evolution of an initial pure mechanical excited state, in analogy with the spontaneous emission from excited atoms. By considering a coherent drive of the mirror, using a master-equation approach to take losses into account, we are able to study the dynamical Casimir effect for optomechanical coupling strengths ranging from weak to ultrastrong. We find that a resonant production of photons out of the vacuum can be observed even for mechanical frequencies lower than the cavity-mode frequency. Since high mechanical frequencies, which are hard to achieve experimentally, were thought to be imperative for realizing the dynamical Casimir effect, this result removes one of the major obstacles for the observation of this long-sought effect. We also find that the dynamical Casimir effect can create entanglement between the oscillating mirror and the radiation produced by its motion in the vacuum field, and that vacuum Casimir-Rabi oscillations can occur. Finally, we also show that all these findings apply not only to optomechanical systems, but also to parametric amplifiers operating in the fully quantum regime.

  13. Spiral multiple-effect diffusion solar still coupled with vacuum-tube collector and heat pipe

    KAUST Repository

    Huang, Bin-Juine; Chong, Tze-Ling; Wu, Po-Hsien; Dai, Han-Yi; Kao, Yeong-Chuan

    2015-01-01

    © 2015 Elsevier B.V. A novel solar still with spiral-shape multiple-effect diffusion unit is developed in the present study. The test results of a 14-effect unit coupled with vacuum-tube solar collector (absorber area 1.08m2) show that the highest

  14. Multiple-effect diffusion solar still coupled with a vacuum-tube collector and heat pipe

    KAUST Repository

    Chong, Tze-Ling; Huang, Bin-Juine; Wu, Po-Hsien; Kao, Yeong-Chuan

    2014-01-01

    The present study develops a multiple-effect diffusion solar still (MEDS) with a bended-plate design in multiple-effect diffusion unit (MDU) to solve the peel-off problem of wick material. The MDU is coupled with a vacuum-tube solar collector

  15. Vessel size effect on the characteristic frequency of the free surface fluctuations

    International Nuclear Information System (INIS)

    Nam, Ho Yun; Kim, Min Joon; Kim, Jong Man; Choi, Byoung Hae

    2004-01-01

    Studies of the free surface fluctuations is one of the important topics in a liquid metal nuclear reactor using sodium as the coolant that has a free surface in the upper plenum of the reactor vessel. The main reasons for the study on the free surface fluctuations can be summarized as: 1. to secure the structural integrity of a reactor vessel by considering the thermal stress on the vessel wall induced by the fluctuations of the free surface between the hot sodium and cold cover gas, 2. to prevent the cover gas entrainment at the free surface of the sodium because the entrained gas causes a change in the reactivity and also reduces the heat removal capability in the core. Some experimental studies on the free surface fluctuations have been reported. However, most of them focus on the gas entrainment phenomena and only a few works concern the basic characteristics of the free surface fluctuations. Since the thermal stress on the wall is strongly dependent on the amplitude and frequency of the free surface fluctuations, studies on the amplitudes and frequencies should receive more attention. In Nam, empirical formulae on the amplitudes and frequencies with respect to the geometric and hydraulic parameters were introduced. It is an interesting result, but the experiment was performed within the parameter range near the onset point of the fluctuations. In the real reactor condition, larger sized fluctuations may exist and the formula needs to be modified. In this study, we performed experiments on the free surface fluctuations, especially on larger sized fluctuations and made an analysis of the amplitudes and frequencies. The main focus of this paper is the effect of the vessel size on the characteristic frequencies. It is thought to be helpful for finding the scaling laws, for example, designing a scale-down experiment

  16. Life cycle environmental impacts of vacuum cleaners and the effects of European regulation.

    Science.gov (United States)

    Gallego-Schmid, Alejandro; Mendoza, Joan Manuel F; Jeswani, Harish Kumar; Azapagic, Adisa

    2016-07-15

    Energy efficiency of vacuum cleaners has been declining over the past decades while at the same time their number in Europe has been increasing. The European Commission has recently adopted an eco-design regulation to improve the environmental performance of vacuum cleaners. In addition to the existing directive on waste electrical and electronic equipment (WEEE), the regulation could potentially have significant effects on the environmental performance of vacuum cleaners. However, the scale of the effects is currently unknown, beyond scant information on greenhouse gas emissions. Thus, this paper considers for the first time life cycle environmental impacts of vacuum cleaners and the effects of the implementation of these regulations at the European level. The effects of electricity decarbonisation, product lifetime and end-of-life disposal options are also considered. The results suggest that the implementation of the eco-design regulation alone will reduce significantly the impacts from vacuum cleaners (37%-44%) by 2020 compared with current situation. If business as usual continued and the regulation was not implemented, the impacts would be 82%-109% higher by 2020 compared to the impacts with the implementation of the regulation. Improvements associated with the implementation of the WEEE directive will be much smaller (impacts would be 2%-21% higher by 2020 relative to the impacts with the implementation of the directive. Further improvements in most impacts (6%-20%) could be achieved by decarbonising the electricity mix. Therefore, energy efficiency measures must be accompanied by appropriate actions to reduce the environmental impacts of electricity generation; otherwise, the benefits of improved energy efficiency could be limited. Moreover, because of expected lower life expectancy of vacuum cleaners and limited availability of some raw materials, the eco-design regulation should be broadened to reduce the impacts from raw materials, production and end

  17. Life cycle environmental impacts of vacuum cleaners and the effects of European regulation

    Energy Technology Data Exchange (ETDEWEB)

    Gallego-Schmid, Alejandro, E-mail: alejandro.gallegoschmid@manchester.ac.uk; Mendoza, Joan Manuel F.; Jeswani, Harish Kumar; Azapagic, Adisa

    2016-07-15

    Energy efficiency of vacuum cleaners has been declining over the past decades while at the same time their number in Europe has been increasing. The European Commission has recently adopted an eco-design regulation to improve the environmental performance of vacuum cleaners. In addition to the existing directive on waste electrical and electronic equipment (WEEE), the regulation could potentially have significant effects on the environmental performance of vacuum cleaners. However, the scale of the effects is currently unknown, beyond scant information on greenhouse gas emissions. Thus, this paper considers for the first time life cycle environmental impacts of vacuum cleaners and the effects of the implementation of these regulations at the European level. The effects of electricity decarbonisation, product lifetime and end-of-life disposal options are also considered. The results suggest that the implementation of the eco-design regulation alone will reduce significantly the impacts from vacuum cleaners (37%–44%) by 2020 compared with current situation. If business as usual continued and the regulation was not implemented, the impacts would be 82%–109% higher by 2020 compared to the impacts with the implementation of the regulation. Improvements associated with the implementation of the WEEE directive will be much smaller (< 1% in 2020). However, if the WEEE directive did not exist, then the impacts would be 2%–21% higher by 2020 relative to the impacts with the implementation of the directive. Further improvements in most impacts (6%–20%) could be achieved by decarbonising the electricity mix. Therefore, energy efficiency measures must be accompanied by appropriate actions to reduce the environmental impacts of electricity generation; otherwise, the benefits of improved energy efficiency could be limited. Moreover, because of expected lower life expectancy of vacuum cleaners and limited availability of some raw materials, the eco-design regulation should

  18. Life cycle environmental impacts of vacuum cleaners and the effects of European regulation

    International Nuclear Information System (INIS)

    Gallego-Schmid, Alejandro; Mendoza, Joan Manuel F.; Jeswani, Harish Kumar; Azapagic, Adisa

    2016-01-01

    Energy efficiency of vacuum cleaners has been declining over the past decades while at the same time their number in Europe has been increasing. The European Commission has recently adopted an eco-design regulation to improve the environmental performance of vacuum cleaners. In addition to the existing directive on waste electrical and electronic equipment (WEEE), the regulation could potentially have significant effects on the environmental performance of vacuum cleaners. However, the scale of the effects is currently unknown, beyond scant information on greenhouse gas emissions. Thus, this paper considers for the first time life cycle environmental impacts of vacuum cleaners and the effects of the implementation of these regulations at the European level. The effects of electricity decarbonisation, product lifetime and end-of-life disposal options are also considered. The results suggest that the implementation of the eco-design regulation alone will reduce significantly the impacts from vacuum cleaners (37%–44%) by 2020 compared with current situation. If business as usual continued and the regulation was not implemented, the impacts would be 82%–109% higher by 2020 compared to the impacts with the implementation of the regulation. Improvements associated with the implementation of the WEEE directive will be much smaller (< 1% in 2020). However, if the WEEE directive did not exist, then the impacts would be 2%–21% higher by 2020 relative to the impacts with the implementation of the directive. Further improvements in most impacts (6%–20%) could be achieved by decarbonising the electricity mix. Therefore, energy efficiency measures must be accompanied by appropriate actions to reduce the environmental impacts of electricity generation; otherwise, the benefits of improved energy efficiency could be limited. Moreover, because of expected lower life expectancy of vacuum cleaners and limited availability of some raw materials, the eco-design regulation should

  19. Effect of osmotic dehydration and vacuum-frying parameters to produce high-quality mango chips.

    Science.gov (United States)

    Nunes, Yolanda; Moreira, Rosana G

    2009-09-01

    Mango (Mangifera indica L.) is a fruit rich in flavor and nutritional values, which is an excellent candidate for producing chips. The objective of this study was to develop high-quality mango chips using vacuum frying. Mango ("Tommy Atkins") slices were pretreated with different maltodextrin concentrations (40, 50, and 65, w/v), osmotic dehydration times (45, 60, and 70 min), and solution temperatures (22 and 40 degrees C). Pretreated slices were vacuum fried at 120, 130, and 138 degrees C and product quality attributes (oil content, texture, color, carotenoid content) determined. The effect of frying temperatures at optimum osmotic dehydration times (65 [w/v] at 40 degrees C) was assessed. All samples were acceptable (scores > 5) to consumer panelists. The best mango chips were those pretreated with 65 (w/v) concentration for 60 min and vacuum fried at 120 degrees C. Mango chips under atmospheric frying had less carotenoid retention (32%) than those under vacuum frying (up to 65%). These results may help further optimize vacuum-frying processing of high-quality fruit-based snacks.

  20. Effect of Vacuum Frying on Changes in Quality Attributes of Jackfruit (Artocarpus heterophyllus Bulb Slices

    Directory of Open Access Journals (Sweden)

    Tanushree Maity

    2014-01-01

    Full Text Available The effect of frying temperatures and durations on the quality of vacuum fried jackfruit (JF chips was evaluated. Moisture content and breaking force of JF chips decreased with increase in frying temperature and time during vacuum frying whereas the oil content increased. The frying time for JF chips was found to be 30, 25, and 20 minutes at 80, 90, and 100°C, respectively. JF chips fried at higher temperature resulted in maximum shrinkage (48%. The lightness in terms of hunter L* value decreased significantly (P<0.05 during frying. Sensory evaluation showed maximum acceptability for JF chips fried at 90°C for 25 min. Frying under vacuum at lower temperatures was found to retain bioactive compounds such as total phenolics, total flavonoids, and total carotenoids in JF chips. Almost 90% of carotenoids were lost from the samples after 30 min of frying at 100°C.

  1. Effect of Vacuum Frying on Changes in Quality Attributes of Jackfruit (Artocarpus heterophyllus) Bulb Slices.

    Science.gov (United States)

    Maity, Tanushree; Bawa, A S; Raju, P S

    2014-01-01

    The effect of frying temperatures and durations on the quality of vacuum fried jackfruit (JF) chips was evaluated. Moisture content and breaking force of JF chips decreased with increase in frying temperature and time during vacuum frying whereas the oil content increased. The frying time for JF chips was found to be 30, 25, and 20 minutes at 80, 90, and 100°C, respectively. JF chips fried at higher temperature resulted in maximum shrinkage (48%). The lightness in terms of hunter L (*) value decreased significantly (P < 0.05) during frying. Sensory evaluation showed maximum acceptability for JF chips fried at 90°C for 25 min. Frying under vacuum at lower temperatures was found to retain bioactive compounds such as total phenolics, total flavonoids, and total carotenoids in JF chips. Almost 90% of carotenoids were lost from the samples after 30 min of frying at 100°C.

  2. Quantum vacuum effects as generalized f(R) gravity: Application to stars

    International Nuclear Information System (INIS)

    Santos, Emilio

    2010-01-01

    It is assumed that, for weak space-time curvature, the main gravitational effect of the quantum vacuum stress energy corresponds to adding two terms to the Einstein-Hilbert action, proportional to the square of the curvature scalar and to the contraction of two Ricci tensors, respectively. It is shown that compatibility with terrestrial and Solar System observations implies that the square roots of the coefficients of these terms should be either a few millimeters or a few hundred meters. It is shown that the vacuum contribution increase the stability of massive white dwarfs.

  3. Effect of magnetic and density fluctuations on the propagation of lower hybrid waves in tokamaks

    Science.gov (United States)

    Vahala, George; Vahala, Linda; Bonoli, Paul T.

    1992-12-01

    Lower hybrid waves have been used extensively for plasma heating, current drive, and ramp-up as well as sawteeth stabilization. The wave kinetic equation for lower hybrid wave propagation is extended to include the effects of both magnetic and density fluctuations. This integral equation is then solved by Monte Carlo procedures for a toroidal plasma. It is shown that even for magnetic/density fluctuation levels on the order of 10-4, there are significant magnetic fluctuation effects on the wave power deposition into the plasma. This effect is quite pronounced if the magnetic fluctuation spectrum is peaked within the plasma. For Alcator-C-Mod [I. H. Hutchinson and the Alcator Group, Proceedings of the IEEE 13th Symposium on Fusion Engineering (IEEE, New York, 1990), Cat. No. 89CH 2820-9, p. 13] parameters, it seems possible to be able to infer information on internal magnetic fluctuations from hard x-ray data—especially since the effects of fluctuations on electron power density can explain the hard x-ray data from the JT-60 tokamak [H. Kishimoto and JT-60 Team, in Plasma Physics and Controlled Fusion (International Atomic Energy Agency, Vienna, 1989), Vol. I, p. 67].

  4. Superconductivity versus quantum criticality: Effects of thermal fluctuations

    Science.gov (United States)

    Wang, Huajia; Wang, Yuxuan; Torroba, Gonzalo

    2018-02-01

    We study the interplay between superconductivity and non-Fermi liquid behavior of a Fermi surface coupled to a massless SU(N ) matrix boson near the quantum critical point. The presence of thermal infrared singularities in both the fermionic self-energy and the gap equation invalidates the Eliashberg approximation, and makes the quantum-critical pairing problem qualitatively different from that at zero temperature. Taking the large N limit, we solve the gap equation beyond the Eliashberg approximation, and obtain the superconducting temperature Tc as a function of N . Our results show an anomalous scaling between the zero-temperature gap and Tc. For N greater than a critical value, we find that Tc vanishes with a Berezinskii-Kosterlitz-Thouless scaling behavior, and the system retains non-Fermi liquid behavior down to zero temperature. This confirms and extends previous renormalization-group analyses done at T =0 , and provides a controlled example of a naked quantum critical point. We discuss the crucial role of thermal fluctuations in relating our results with earlier work where superconductivity always develops due to the special role of the first Matsubara frequency.

  5. Reparation effects of vacuum wound therapy in patients with diabetic foot syndrome

    Directory of Open Access Journals (Sweden)

    Besedin A.M.

    2015-09-01

    Full Text Available Vacuum Therapy (Vacuum-assisted closure, VAC - a method of complex therapy which is used to improve the healing of both acute chronic wounds in patients with diabetic foot syndrome. Due to widespread introduction of this technique, unique cell, extracellular and general effects of its use in the treatment of patients with purulent-necrotic complications of diabetic foot syndrome, a technique of vacuum wound therapy has been successfully used in many surgical departments of Ukraine. Despite the diversity of the clinical effects of VAC-therapy and appearance of number of publications, in the domestic and foreign literature physiological basis of this method have not been studied completely. The effectiveness of vacuum therapy explain: the reduction of the size of the wound, the stabilization of the wound environment (due to the removal of inflammatory mediators and cytokines, microdeformation and remodeling of cell, rows reduction of edema, reduction of bacterial contamination, etc. At the same time, mechanisms of blood flow enhancement at different duration of VAC-therapy use, remain unclear its effect on the third phase of wound healing process as well.

  6. Experimental and theoretical analysis of vacuum circuit breaker prestrike effect on a transformer

    NARCIS (Netherlands)

    Popov, M.; Smeets, R.P.P.; Van der Sluis, L.; De Herdt, H.; Declerq, J.

    2009-01-01

    The work presented in this paper deals with the investigation of circuit breaker prestrike effect that occurs during energizing a distribution transformer. An experimental test setup that consists of a supply transformer, a vacuum circuit breaker (VCB), a cable and a test transformer is built, and

  7. Quantum friction across the vacuum

    International Nuclear Information System (INIS)

    Ebelein, C.

    1998-01-01

    Friction is so ubiquitous that it seems to be almost trivially familiar. The rubbing of two solid surfaces is opposed by a resistance and accompanied by the production of heat. Engineers still dream of perfectly smooth surfaces that can be moved against each other without any friction. However, this dream has now been shattered by John Pendry of Imperial College, London, who has published a theory that shows that even two perfectly smooth surfaces can experience an appreciable friction when moved relative to each other (J. Phys.: Condens. Matter 1997 9 10301-10320). Moreover, the two surfaces he considers are not even in contact but separated by a gap a lattice constant or so wide. The explanation of this lies in what Pendry calls the shearing of the vacuum in the gap. In quantum physics the vacuum is not just empty nothingness; it is full of virtually everything. The vacuum abounds with virtual photons. These zero-point fluctuations cannot normally be seen, but they give the vacuum a structure that manifests itself in a variety of effects (for example, the Casimir effect). A more subtle, yet more familiar, manifestation of these zero-point fluctuations is the van der Waals force. The effect described by Pendry can be understood as a van der Waals interaction between two infinite slabs of dielectric material moving relative to each other. Each slab will be aware of the motion of the other because the virtual photons reflected from the moving surface are Doppler-shifted up or down, depending on the direction of the photon wave vector relative to the motion. Pendry shows that this asymmetry in the exchange of virtual photons can lead to an appreciable effect for materials of reasonably strong dispersion. (author)

  8. Vacuum nonlinear electrodynamic polarization effects in hard emission of pulsars and magnetars

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, V.I.; Sokolov, V.A.; Svertilov, S.I., E-mail: vid.msu@yandex.ru, E-mail: sokolov.sev@inbox.ru, E-mail: sis@coronas.ru [Physics Department, Moscow State University, Moscow (Russian Federation)

    2017-09-01

    The nonlinear electrodynamics influence of pulsar magnetic field on the electromagnetic pulse polarization is discussed from the point of observation interpretation. The calculations of pulsar magnetic field impact on the electromagnetic pulse polarization are made in such a way to make it easier to interpret these effects in space experiments. The law of hard emission pulse propagation in the pulsar magnetic field according to the vacuum (nonlinear electrodynamics is obtained. It has been shown, that due to the birefringence in the vacuum the front part of any hard emission pulse coming from a pulsar should be linearly polarized and the rest of pulse can have arbitrary polarization. The observational possibilities of vacuum birefringence are discussed. In this paper we give the estimations of detector parameters such as effective area, exposure time and necessity of polarization measurements with high accuracy. The combination of large area and extremely long exposure time gives the good opportunity to search the fine polarization effects like vacuum nonlinear electrodynamics birefringence.

  9. Effect of static porosity fluctuations on reactive transport in a porous medium

    Science.gov (United States)

    L'Heureux, Ivan

    2018-02-01

    Reaction-diffusive transport phenomena in porous media are ubiquitous in engineering applications, biological and geochemical systems. The porosity field is usually random in space, but most models consider the porosity field as a well-defined deterministic function of space and time and ignore the porosity fluctuations. They use a reaction-diffusion equation written in terms of an average porosity and average concentration fields. In this contribution, we treat explicitly the effect of spatial porosity fluctuations on the dynamics of a concentration field for the case of a one-dimensional reaction-transport system with nonlinear kinetics. Three basic assumptions are considered. (i) The porosity fluctuations are assumed to have Gaussian properties and an arbitrary variance; (ii) we assume that the noise correlation length is small compared to the relevant macroscopic length scale; (iii) and we assume that the kinetics of the reactive term in the equations for the fluctuations is a self-consistently determined constant. Elimination of the fluctuating part of the concentration field from the dynamics leads to a renormalized equation involving the average concentration field. It is shown that the noise leads to a renormalized (generally smaller) diffusion coefficient and renormalized kinetics. Within the framework of the approximations used, numerical simulations are in agreement with our theory. We show that the porosity fluctuations may have a significant effect on the transport of a reactive species, even in the case of a homogeneous average porosity.

  10. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure.

    Science.gov (United States)

    El-Mashad, Hamed M; Zeeman, Grietje; van Loon, Wilko K P; Bot, Gerard P A; Lettinga, Gatze

    2004-11-01

    The influence of temperature, 50 and 60 degrees C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature fluctuations has been studied. In the daily downward temperature fluctuation regime the temperatures of each reactor was reduced by 10 degrees C for 10 h while in the daily upward fluctuation regime the temperature of each reactor was increased 10 degrees C for 5 h. The results show that the methane production rate at 60 degrees C is lower than that at 50 degrees C at all experimental conditions of imposed HRT except when downward temperature fluctuations were applied at an HRT of 10 days. It also was found that the free ammonia concentration not only affects the acetate-utilising bacteria but also the hydrolysis and acidification process. The upward temperature fluctuation affects the maximum specific methanogenesis activity more severely as compared to imposed downward temperature fluctuations. The results clearly reveal the possibility of using available solar energy at daytime to heat up the reactor(s) without the need of heat storage during nights, especially at an operational temperature of 50 degrees C and at a 20 days HRT, and without the jeopardising of the overheating.

  11. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure

    Energy Technology Data Exchange (ETDEWEB)

    El-Mashad, H.M. [Mansoura University, El-Mansoura (Egypt). Faculty of Agriculture, Department of Agricultural Engineering; Zeeman, G.; Van Loon, W.K.P.; Bot, G.P.A.; Lettinga, G. [Wageningen University Agrotechnion (Netherlands). Department of Agrotechnology and Food Sciences

    2004-11-01

    The influence of temperature, 50 and 60 {sup o}C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature fluctuations has been studied. In the daily downward temperature fluctuation regime the temperatures of each reactor was reduced by 10 {sup o}C for 10 h while in the daily upward fluctuation regime the temperature of each reactor was increased 10 {sup o}C for 5 h. The results show that the methane production rate at 60 {sup o}C is lower than that at 50 {sup o}C at all experimental conditions of imposed HRT except when downward temperature fluctuations were applied at an HRT of 10 days. It also was found that the free ammonia concentration not only affects the acetate-utilising bacteria but also the hydrolysis and acidification process. The upward temperature fluctuation affects the maximum specific methanogenesis activity more severely as compared to imposed downward temperature fluctuations. The results clearly reveal the possibility of using available solar energy at daytime to heat up the reactor(s) without the need of heat storage during nights, especially at an operational temperature of 50 {sup o}C and at a 20 days HRT, and without the jeopardising of the overheating. (author)

  12. Adaptation to Temporally Fluctuating Environments by the Evolution of Maternal Effects.

    Directory of Open Access Journals (Sweden)

    Snigdhadip Dey

    2016-02-01

    Full Text Available All organisms live in temporally fluctuating environments. Theory predicts that the evolution of deterministic maternal effects (i.e., anticipatory maternal effects or transgenerational phenotypic plasticity underlies adaptation to environments that fluctuate in a predictably alternating fashion over maternal-offspring generations. In contrast, randomizing maternal effects (i.e., diversifying and conservative bet-hedging, are expected to evolve in response to unpredictably fluctuating environments. Although maternal effects are common, evidence for their adaptive significance is equivocal since they can easily evolve as a correlated response to maternal selection and may or may not increase the future fitness of offspring. Using the hermaphroditic nematode Caenorhabditis elegans, we here show that the experimental evolution of maternal glycogen provisioning underlies adaptation to a fluctuating normoxia-anoxia hatching environment by increasing embryo survival under anoxia. In strictly alternating environments, we found that hermaphrodites evolved the ability to increase embryo glycogen provisioning when they experienced normoxia and to decrease embryo glycogen provisioning when they experienced anoxia. At odds with existing theory, however, populations facing irregularly fluctuating normoxia-anoxia hatching environments failed to evolve randomizing maternal effects. Instead, adaptation in these populations may have occurred through the evolution of fitness effects that percolate over multiple generations, as they maintained considerably high expected growth rates during experimental evolution despite evolving reduced fecundity and reduced embryo survival under one or two generations of anoxia. We develop theoretical models that explain why adaptation to a wide range of patterns of environmental fluctuations hinges on the existence of deterministic maternal effects, and that such deterministic maternal effects are more likely to contribute to

  13. Laser effects on graphene oxide irradiated in high vacuum

    Czech Academy of Sciences Publication Activity Database

    Torrisi, L.; Silipigni, L.; Cutroneo, Mariapompea

    2018-01-01

    Roč. 173, 1-2 (2018), s. 73-84 ISSN 1042-0150 R&D Projects: GA MŠk LM2015056; GA ČR GA16-05167S Institutional support: RVO:61389005 Keywords : graphene oxide * laser irradiation * laser-generated plasma * radiation effects Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 0.443, year: 2016

  14. Effect of Various Pretreatments on Quality Attributes of Vacuum-Fried Shiitake Mushroom Chips

    Directory of Open Access Journals (Sweden)

    Aiqing Ren

    2018-01-01

    Full Text Available The objective of this study is to investigate the effects of pretreatments on the quality of vacuum-fried shiitake mushroom slices. Four different pretreatments addressed in this study were (1 blanching as control, (2 blanching and osmotic dehydration with maltodextrin (MD solution, (3 blanching, osmotic dehydration, and coating with sodium carboxymethyl cellulose (CMC, (4 blanching and osmotic dehydration, followed by freezing. All samples were pretreated and then fried in palm oil at 90°C with vacuum degree of −0.095 MPa for 30 min. The results showed that pretreatments significantly (p0.05 differences of fried chip in the texture among the four different pretreatments. The aw values of all the fried chips were less than 0.38, indicating that the products had a long shelf life. Therefore, the blanching, osmotic dehydration, and coating pretreatment before vacuum frying was the most suitable pretreatment for vacuum-fried shiitake mushroom chips.

  15. Numerical Study on Radiation Effects to Evaporator in Natural Vacuum Solar Desalination System

    Science.gov (United States)

    Siregar, R. E. T.; Ronowikarto, A. D.; Setyawan, E. Y.; Ambarita, H.

    2018-01-01

    The need for clean water is increasing day by day due to the increasing factor of living standard of mankind, hence designed natural vacuum solar desalination. The natural vacuum Solar desalination is studied experimentally. A small-scale natural vacuum desalination study consists of evaporator and condenser as the main components designed and manufactured. To transfer heat from the solar collector into the evaporator, the fluid transfer system uses a pump powered by a solar cell. Thus, solar collectors are called hybrid solar collectors. The main purpose of this exposure is to know the characteristics of the radiation effects on incoming energy on the evaporator during the process. This system is tested by exposing the unit to the solar radiation in the 4th floor building in Medan. The experiment was conducted from 8.00 to 16.00 local time. The results show that natural vacuum solar desalination with hybrid solar collectors can be operated perfectly. If the received radiation is high, then the incoming energy received by the evaporator will also be high. From measurements with HOBO microstation, obtained the highest radiation 695.6 W/m2, and the calculation result of incoming energy received evaporator obtained highest result 1807.293 W.

  16. Effects of vacuum suctioning and strategic drape tenting on oxygen concentration in a simulated surgical field.

    Science.gov (United States)

    Kung, Theodore A; Kong, Sarah W; Aliu, Oluseyi; Azizi, Jahan; Kai, Salim; Cederna, Paul S

    2016-02-01

    To investigate the isolated and combined effects of vacuum suctioning and strategic drape tenting on oxygen concentration in an experimental setting. Experimental. Clinical simulation center of a university-affiliated hospital. Mannequin simulation of a patient undergoing facial surgery under sedation anesthesia. Supplemental oxygen was delivered via nasal cannula. Vacuum suctioning and strategic drape tenting. The experimental trials entailed measuring oxygen concentration around the nasal cannula continuously either in the presence or absence of a standard operating room vacuum suction system and strategic tenting of surgical drapes. The primary outcome was the time required for oxygen concentration to reach 21%. In the control group (without suction or strategic tenting), a mean time of 180 seconds elapsed until the measured oxygen concentration reached 21% after cessation of oxygen delivery. Use of a vacuum suction device alone (110 seconds; P strategic tenting (110 seconds; P strategic tenting of surgical drapes has a theoretical benefit to decreasing the pooling of oxygen around the surgical site, further investigation is necessary before its routine use is recommended. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Effect of beam-attenuation modulation on fluctuation measurements by heavy-ion beam probe

    International Nuclear Information System (INIS)

    Ross, D.W.; Sloan, M.L.; Wootton, A.J.

    1991-03-01

    Beam-attenuation modulation arising from density fluctuations along the orbit of the heavy-ion beam probe can distort the local amplitude, coherence, and phase derived from one- and two-point correlation measurements. Path-integral expressions for these effects are derived and applications to TEXT data are discussed. The effects depend critically on the ratio of the average fluctuation amplitude, n e , along the beam path to the local n e at the sample volume. Because the fluctuation amplitude is small in the core and rises sharply toward the plasma edge, the contamination effect is negligible in a radial zone near the edge but rises sharply to the interior of a critical radius. With increasing average plasma density, bar n e , the interior contamination increases strongly and the critical radius moves outward. 16 refs., 12 figs

  18. Effects of barrier fluctuation on the tunneling dynamics in the ...

    Indian Academy of Sciences (India)

    the present paper is to study the effect of classical subsystem or more importantly the effect of .... of chaos-assisted tunneling has been a topic of interest for various researchers over many .... state causes the increase in tunneling rate constant.

  19. Quantum interference effects for the electronic fluctuations in quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, J.G.G.S. [Universidade Federal da Paraiba (UFPB), Rio Tinto, PB (Brazil). Departamento de Ciencias Exatas; Hussein, M.S. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica; Barbosa, A.L.R. [Universidade Federal Rural de Pernambuco (UAEADTec/UFRPE), Recife, PE (Brazil). Unidade Academica de Ensino a Distancia. Pos-Graduacao em Fisica Aplicada

    2014-07-01

    For the main quantum interference term of coherent electronic transport, we study the effect of temperature, perpendicular and/or parallel magnetic fields, spin-orbit coupling and tunneling rates in both metallic grains and mesoscopic heterostructures. We show that the Zeeman effects determines a crucial way to characterize the quantum interference phenomena of the noise for anisotropic systems (mesoscopic heterostructures), qualitatively distinct from those observed in isotropic structures (metallic grains). (author)

  20. Quantum interference effects for the electronic fluctuations in quantum dots

    International Nuclear Information System (INIS)

    Ramos, J.G.G.S.; Hussein, M.S.; Barbosa, A.L.R.

    2014-01-01

    For the main quantum interference term of coherent electronic transport, we study the effect of temperature, perpendicular and/or parallel magnetic fields, spin-orbit coupling and tunneling rates in both metallic grains and mesoscopic heterostructures. We show that the Zeeman effects determines a crucial way to characterize the quantum interference phenomena of the noise for anisotropic systems (mesoscopic heterostructures), qualitatively distinct from those observed in isotropic structures (metallic grains). (author)

  1. Effects of density gradients and fluctuations at the plasma edge on ECEI measurements at ASDEX Upgrade

    NARCIS (Netherlands)

    Vanovac, B.; Wolfrum, E.; Denk, S. S.; Mink, F.; Laggner, F. M.; Birkenmeier, G.; Willensdorfer, M.; Viezzer, E.; Hoelzl, M.; Freethy, S. J.; Dunne, M. G.; Lessig, A.; Luhmann, N. C.; ASDEX Upgrade team,; EUROfusion MST1 Team,

    2018-01-01

    Electron cyclotron emission imaging (ECEI) provides measurements of electron temperature (T-e) and its fluctuations (delta T-e). However, when measuring at the plasma edge, in the steep gradient region, radiation transport effects must be taken into account. It is shown that due to these effects,

  2. Mass corrections to Green functions in instanton vacuum model

    International Nuclear Information System (INIS)

    Esaibegyan, S.V.; Tamaryan, S.N.

    1987-01-01

    The first nonvanishing mass corrections to the effective Green functions are calculated in the model of instanton-based vacuum consisting of a superposition of instanton-antiinstanton fluctuations. The meson current correlators are calculated with account of these corrections; the mass spectrum of pseudoscalar octet as well as the value of the kaon axial constant are found. 7 refs

  3. Numerical simulation of the effect of dissipation and phase fluctuation in a direct communication scheme

    International Nuclear Information System (INIS)

    Li, Fu; Zhu, Shi-Yao; Zhang, Jun-Xiang

    2015-01-01

    Recently, the direct counterfactual communication protocol, proposed by Salih et al (2013 Phys. Rev. Lett. 110 170502) using a single photon source under ideal conditions (no dissipation, no phase fluctuation and an infinite number of beam splitters), has attracted much interest from a broad range of scientists. In order to put the direct communication protocol into a realistic framework, we numerically simulate the effect of the dissipation and the phase fluctuation with a finite number of beam splitters. Our calculation shows that the dissipation and phase fluctuation will dramatically decrease the reliability and the efficiency of communication, and even corrupt the communication. To counteract the negative effect of dissipation, we propose the balanced dissipation method, which substantially improves the reliability of the protocol at the expense of decreasing communication efficiency. Meanwhile, our theoretical derivation shows that the reliability and efficiency of communication are independent of the input state: a single photon state or a coherent state. (paper)

  4. Fluctuating functions related to quality of life in advanced Parkinson disease: effects of duodenal levodopa infusion.

    Science.gov (United States)

    Isacson, D; Bingefors, K; Kristiansen, I S; Nyholm, D

    2008-12-01

    To assess fluctuations in quality of life (QoL) and motor performance in patients with advanced Parkinson disease (PD) treated with continuous daytime duodenal levodopa/carbidopa infusion or conventional therapy. Of 18 patients completing a 6-week trial (DIREQT), 12 were followed for up to 6 months and assessed using electronic diaries and the PD Questionnaire-39 (PDQ-39). During the trial and follow-up, major diurnal fluctuations were observed, especially for hyperkinesia, 'off' time, ability to walk and depression. Duodenal infusion was associated with significantly more favourable outcomes compared with conventional treatment for satisfaction with overall functioning, 'off' time and ability to walk, with improved outcomes with PDQ-39. Relative to conventional treatment, infusion therapy may stabilize and significantly improve motor function and patient's QoL. The potential for daily fluctuation in PD symptoms means single measures of treatment effectiveness can result in bias in effect estimates and hence repeated measures are recommended.

  5. The dependence of the nuclear charge form factor on short range correlations and surface fluctuation effects

    International Nuclear Information System (INIS)

    Massen, S. E.; Garistov, V. P.; Grypeos, M. E.

    1996-01-01

    The effects of nuclear surface fluctuations on harmonic oscillator elastic charge form factor of light nuclei are investigated, simultaneously approximating the short-range correlations through a Jastrow correlation factor. Inclusion of the surface fluctuation effects within this description, by truncating the cluster expansion at the two-body part, is found to improve somewhat the fit to the elastic charge form-factor of 16 O and 40 Ca. However, the convergence of the cluster expansion is expected to deteriorate. An additional finding is that surface-fluctuation correlations produce a drastic change in the asymptotic behaviour of the point-proton form-factor, which now falls off quite slowly (i.e. as const.q -4 ) at large values of the momentum transfer q

  6. Numerical simulation of the effect of dissipation and phase fluctuation in a direct communication scheme

    Science.gov (United States)

    Li, Fu; Zhang, Jun-Xiang; Zhu, Shi-Yao

    2015-06-01

    Recently, the direct counterfactual communication protocol, proposed by Salih et al (2013 Phys. Rev. Lett. 110 170502) using a single photon source under ideal conditions (no dissipation, no phase fluctuation and an infinite number of beam splitters), has attracted much interest from a broad range of scientists. In order to put the direct communication protocol into a realistic framework, we numerically simulate the effect of the dissipation and the phase fluctuation with a finite number of beam splitters. Our calculation shows that the dissipation and phase fluctuation will dramatically decrease the reliability and the efficiency of communication, and even corrupt the communication. To counteract the negative effect of dissipation, we propose the balanced dissipation method, which substantially improves the reliability of the protocol at the expense of decreasing communication efficiency. Meanwhile, our theoretical derivation shows that the reliability and efficiency of communication are independent of the input state: a single photon state or a coherent state.

  7. Probing gluon number fluctuation effects in future electron–hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, J.T.; Gonçalves, V.P. [Instituto de Física e Matemática, Universidade Federal de Pelotas, Caixa Postal 354, CEP 96010-900, Pelotas, RS (Brazil); Kugeratski, M.S. [Universidade Federal de Santa Catarina, Campus Joinville, Rua Presidente Prudente de Moraes, 406, CEP 89218-000, Joinville, SC (Brazil)

    2014-10-15

    The description of the QCD dynamics in the kinematical range which will be probed in the future electron–hadron colliders is still an open question. Although phenomenological studies indicate that the gluon number fluctuations, which are related to discreteness in the QCD evolution, are negligible at HERA, the magnitude of these effects for the next generation of colliders still should be estimated. In this paper we investigate inclusive and diffractive ep observables considering a model for the physical scattering amplitude which describes the HERA data. Moreover, we estimate, for the first time, the contribution of the fluctuation effects for the nuclear structure functions. Our results indicate that the study of these observables in the future colliders can be useful to constrain the presence of gluon number fluctuations.

  8. Spatial effects on the fluctuations of a nuclear power reactor

    International Nuclear Information System (INIS)

    Salinas-Rodriguez, E.; Rodriguez, R.F.; Wio, H.S.

    1990-01-01

    The effects of spatial inhomogeneities in a nuclear system are studied by using the compounding moments method. In particular, the neutron density and temperature equilibrium correlation functions are explicitly calculated for a realistic linearized nuclear reactor model described in terms of a master equation. (author)

  9. Effect of directional selection for body size on fluctuating asymmetry ...

    Indian Academy of Sciences (India)

    In this study, we investigated whether stress caused by artificial bidirectional selection for body size has any effect on the levels of FA of different morphological traits in Drosophila ananassae. The realised heritability (h2) was higher in low-line females and high-line males, which suggests an asymmetrical response to ...

  10. In Situ Hall Effect Monitoring of Vacuum Annealing of In2O3:H Thin Films

    Directory of Open Access Journals (Sweden)

    Hans F. Wardenga

    2015-02-01

    Full Text Available Hydrogen doped In2O3 thin films were prepared by room temperature sputter deposition with the addition of H2O to the sputter gas. By subsequent vacuum annealing, the films obtain high mobility up to 90 cm2/Vs. The films were analyzed in situ by X-ray photoelectron spectroscopy (XPS and ex situ by X-ray diffraction (XRD, optical transmission and Hall effect measurements. Furthermore, we present results from in situ Hall effect measurements during vacuum annealing of In2O3:H films, revealing distinct dependence of carrier concentration and mobility with time at different annealing temperatures. We suggest hydrogen passivation of grain boundaries as the main reason for the high mobility obtained with In2O3:H films.

  11. Effect of kinematic acceptance on conserved number fluctuations

    International Nuclear Information System (INIS)

    Garg, P.; Singh, B.K.; Mishra, D.K.; Netrakanti, P.K.; Mohanty, A.K.; Mohanty, B.

    2013-01-01

    Studying the moments of distribution for conserved quantities like net-baryon, net-charge and net-strangeness number for systems undergoing strong interactions as in high energy heavy-ion collisions, have recently provided rich physics insights. In the present work, we demonstrate the effect of the above experimental limitations on the physics observables χ (3) /χ (2) and χ (4) /χ (2) using HRG model

  12. IMPROVEMENT OF EQUIPMENT FOR EFFECTIVE HARDENING SAND MIXTURE BY VACUUM MOLDING

    Directory of Open Access Journals (Sweden)

    V. S. Doroshenko

    2016-01-01

    Full Text Available The review deals with the design flask tooling and patterns for effective hardening sand mixture in the vacuum molding (V-Process, and molding on a one-off patterns (Lost Foam Casting. Sealing and evacuating sand mixture – two major factors influence the strength of the casting mold and casting quality, management practices which will enable to improve the casting process.

  13. Structural-acoustic coupling effects on the non-vacuum packaging vibratory cylinder gyroscope.

    Science.gov (United States)

    Xi, Xiang; Wu, Xuezhong; Wu, Yulie; Zhang, Yongmeng; Tao, Yi; Zheng, Yu; Xiao, Dingbang

    2013-12-13

    The resonant shells of vibratory cylinder gyroscopes are commonly packaged in metallic caps. In order to lower the production cost, a portion of vibratory cylinder gyroscopes do not employ vacuum packaging. However, under non-vacuum packaging conditions there can be internal acoustic noise leading to considerable acoustic pressure which is exerted on the resonant shell. Based on the theory of the structural-acoustic coupling, the dynamical behavior of the resonant shell under acoustic pressure is presented in this paper. A finite element (FE) model is introduced to quantitatively analyze the effect of the structural-acoustic coupling. Several main factors, such as sealing cap sizes and degree of vacuum which directly affect the vibration of the resonant shell, are studied. The results indicate that the vibration amplitude and the operating frequency of the resonant shell will be changed when the effect of structural-acoustic coupling is taken into account. In addition, an experiment was set up to study the effect of structural-acoustic coupling on the sensitivity of the gyroscope. A 32.4 mV/°/s increase of the scale factor and a 6.2 Hz variation of the operating frequency were observed when the radial gap size between the resonant shell and the sealing cap was changed from 0.5 mm to 20 mm.

  14. Structural-Acoustic Coupling Effects on the Non-Vacuum Packaging Vibratory Cylinder Gyroscope

    Directory of Open Access Journals (Sweden)

    Xiang Xi

    2013-12-01

    Full Text Available The resonant shells of vibratory cylinder gyroscopes are commonly packaged in metallic caps. In order to lower the production cost, a portion of vibratory cylinder gyroscopes do not employ vacuum packaging. However, under non-vacuum packaging conditions there can be internal acoustic noise leading to considerable acoustic pressure which is exerted on the resonant shell. Based on the theory of the structural-acoustic coupling, the dynamical behavior of the resonant shell under acoustic pressure is presented in this paper. A finite element (FE model is introduced to quantitatively analyze the effect of the structural-acoustic coupling. Several main factors, such as sealing cap sizes and degree of vacuum which directly affect the vibration of the resonant shell, are studied. The results indicate that the vibration amplitude and the operating frequency of the resonant shell will be changed when the effect of structural-acoustic coupling is taken into account. In addition, an experiment was set up to study the effect of structural-acoustic coupling on the sensitivity of the gyroscope. A 32.4 mV/°/s increase of the scale factor and a 6.2 Hz variation of the operating frequency were observed when the radial gap size between the resonant shell and the sealing cap was changed from 0.5 mm to 20 mm.

  15. Effect of topography on wind turbine power and load fluctuations

    Science.gov (United States)

    Santoni, Christian; Ciri, Umberto; Leonardi, Stefano

    2015-11-01

    Onshore wind turbines produce more than 17 GW in the US, which constitutes 4 . 4 % of all the energy produced. Sites selection is mostly determined by the atmospheric conditions and the topographical characteristics of the region. While the effect of the atmospheric boundary layer had been widely studied, less attention has been given to the effect of the topography on the wind turbine aerodynamics. To address how the topography affects the flow, Large Eddy Simulations of the flow over a wind turbine placed over wavy wall are performed. The wavelength of the wavy terrain, λ, is 1 . 7 D where D is the turbine rotor diameter. Two different values of the height of the wavy wall, a / D = 0 . 05 and a / D = 0 . 10 have been considered. In addition, two positions of the turbine with respect to the wavy wall had been studied, on the crest and trough of the wavy wall and compared with a wind turbine over a flat wall. For the turbine located at the crest, the pressure gradient due to the wavy wall caused a recirculation behind the wind tower 2 . 5 D larger than that of the smooth wall. When placed at the trough of the wavy terrain, the favorable pressure gradient increases the wake velocity near the wall and promotes entrainment into the turbine wake. Numerical simulations were performed on XSEDE TACC, Grant CTS070066. This work was supported by the NSF, grant IIA-1243482 (WINDINSPIRE).

  16. Scalar metric fluctuations in space-time matter inflation

    International Nuclear Information System (INIS)

    Anabitarte, Mariano; Bellini, Mauricio

    2006-01-01

    Using the Ponce de Leon background metric, which describes a 5D universe in an apparent vacuum: G-bar AB =0, we study the effective 4D evolution of both, the inflaton and gauge-invariant scalar metric fluctuations, in the recently introduced model of space-time matter inflation

  17. Current fluctuation of electron and hole carriers in multilayer WSe{sub 2} field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Seung-Pil; Shin, Jong Mok; Jang, Ho-Kyun; Jin, Jun Eon; Kim, Gyu-Tae, E-mail: gtkim@korea.ac.kr [School of Electrical Engineering, Korea University, Seoul 02481 (Korea, Republic of); Kim, Yong Jin; Kim, Young Keun [Department of Materials Science and Engineering, Korea University, Seoul 02481 (Korea, Republic of); Shin, Minju [School of Electrical Engineering, Korea University, Seoul 02481 (Korea, Republic of); IMEP-LAHC, Grenoble INP-MINATEC, 3 Parvis Louis Neel, 38016 Grenoble (France)

    2015-12-14

    Two-dimensional materials have outstanding scalability due to their structural and electrical properties for the logic devices. Here, we report the current fluctuation in multilayer WSe{sub 2} field effect transistors (FETs). In order to demonstrate the impact on carrier types, n-type and p-type WSe{sub 2} FETs are fabricated with different work function metals. Each device has similar electrical characteristics except for the threshold voltage. In the low frequency noise analysis, drain current power spectral density (S{sub I}) is inversely proportional to frequency, indicating typical 1/f noise behaviors. The curves of the normalized drain current power spectral density (NS{sub I}) as a function of drain current at the 10 Hz of frequency indicate that our devices follow the carrier number fluctuation with correlated mobility fluctuation model. This means that current fluctuation depends on the trapping-detrapping motion of the charge carriers near the channel interface. No significant difference is observed in the current fluctuation according to the charge carrier type, electrons and holes that occurred in the junction and channel region.

  18. Effects of an anode sheath on energy and momentum transfer in vacuum arcs

    International Nuclear Information System (INIS)

    Wang, Zhenxing; Zhou, Zhipeng; Tian, Yunbo; Wang, Haoran; Wang, Jianhua; Geng, Yingsan; Liu, Zhiyuan

    2017-01-01

    Anode phenomena under high-current vacuum arcs have a significant impact on the interrupting capacity of vacuum interrupters. However, the vacuum arc energy flux and momentum flux on the anode—which are necessary boundary conditions for simulations—are either set to an imaginary distribution or calculated using simple formulas without considering anode sheath regulatory effects. The objective of this paper is to reveal the anode sheath effects on regulating the energy and momentum transfer from the arc column to the anode surface in vacuum arcs. A particle-in-cell model for the anode sheath is developed. The required input parameters are obtained from a magnetohydrodynamic model for the arc column. From the results, there exists a sheath near the anode with a negative voltage drop. Both the electron density and the ion density significantly decline in the anode sheath region. The kinetic energy of the ions absorbed by the anode consists of directed kinetic energy, random kinetic energy, and sheath acceleration energy. The sheath acceleration energy contribution is the largest, and the random kinetic energy also accounts for a large part that cannot be ignored. The arc pressure on the anode surface is mainly caused by ion impact, and the accelerating effect of the anode sheath on the ions cannot be neglected in pressure calculations. In addition, in the case of an arc current at 15 kA, the input energy and momentum upon the anode surface is not obviously affected by the evaporated atoms at surface temperatures of 1600 K and 2000 K. (paper)

  19. Effect of Dipping and Vacuum Impregnation Coating Techniques with Alginate Based Coating on Physical Quality Parameters of Cantaloupe Melon.

    Science.gov (United States)

    Senturk Parreidt, Tugce; Schmid, Markus; Müller, Kajetan

    2018-04-01

    Edible coating based on sodium alginate solution was applied to fresh-cut cantaloupe melon by dipping and vacuum impregnation coating methods. One aim of this work is to produce more technical information concerning these conventional and novel coating processes. For this purpose, the effect of various coating parameters (dipping time, draining time, time length of the vacuum period, vacuum pressure, atmospheric restoration time) with several levels on physical quality parameters (percentage of weight gain, color, and texture) of noncoated and coated samples were determined in order to define adequate coating process parameters to achieve a successful coating application. Additionally, the effects of dipping and vacuum impregnation processes were compared. Both processes improved the firmness of the melon pieces. However, vacuum impregnation application had higher firmness and weight gain results, and had significant effect (P coating technique and the parameters used significantly affect the physical quality characteristics of coated food products. The work presented produced more technical information concerning dipping and vacuum impregnation coating techniques, along with evaluating the effects of various coating parameters with several levels. The results revealed that vacuum impregnation technique is a successful coating method; however the effects should be carefully assessed for each product. © 2018 Institute of Food Technologists®.

  20. Effective interactions between concentration fluctuations and charge transfer in chemically ordering liquid alloys

    International Nuclear Information System (INIS)

    Akdeniz, Z.; Tosi, M.P.

    1992-08-01

    The correlations between long-wavelength fluctuations of concentration in a liquid binary alloy are determined by a balance between an elastic strain free energy and an Ornstein-Zernike effective interaction. The latter is extracted from thermodynamic data in the case of the Li-Pb system, which is well known to chemically order with stoichiometric composition corresponding to Li 4 Pb. Strong attractive interactions between concentration fluctuations near the composition of chemical ordering originate from electronic charge transfer, which is estimated from the electron-ion partial structure factors as functions of composition in the liquid alloy. (author). 20 refs, 2 figs

  1. Effective temperature and fluctuation-dissipation theorem in athermal granular systems: A review

    International Nuclear Information System (INIS)

    Chen Qiong; Hou Mei-Ying

    2014-01-01

    The definition and the previous measurements of a dynamics-relevant temperature-like quantity in granular media are reviewed for slow and fast particle systems. Especially, the validity of the fluctuation-dissipation theorem in such an athermal system is explored. Experimental evidences for the fluctuation-dissipation theorem relevant effect temperature support the athermal statistical mechanics, which has been widely explored in recent years by physicists. Difficulties encountered in defining temperature or establishing thermodynamics or statistical mechanics in non-equilibrium situations are discussed. (topical review - statistical physics and complex systems)

  2. Effects of angular momentum dissipation on fluctuations of excitation functions in heavy-ion collisions

    International Nuclear Information System (INIS)

    Kun, S.Yu.; Noerenberg, W.; Technische Hochschule Darmstadt

    1992-02-01

    We study the effect from dissipation of relative angular momentum on fluctuations of exitations functions in dissipative heavy-ion collisions. Dissipation and fluctuation of relative angular momentum modify and smooth the time-angle localization of the roating dinuclear system. The secondary maxima in the energy correlation function of the cross-section are shifted to smaller values of the energy difference, the shift depending on the relaxation time and the diffusion coefficient for the angular-momentum dissipation. The results are illustrated for the collision 28 Si(E lab =130MeV)+ 48 Ti. (orig.)

  3. Anomalous Brownian motion of colloidal particle in a nematic environment: effect of the director fluctuations

    Directory of Open Access Journals (Sweden)

    T. Turiv

    2015-06-01

    Full Text Available As recently reported [Turiv T. et al., Science, 2013, Vol. 342, 1351], fluctuations in the orientation of the liquid crystal (LC director can transfer momentum from the LC to a colloid, such that the diffusion of the colloid becomes anomalous on a short time scale. Using video microscopy and single particle tracking, we investigate random thermal motion of colloidal particles in a nematic liquid crystal for the time scales shorter than the expected time of director fluctuations. At long times, compared to the characteristic time of the nematic director relaxation we observe typical anisotropic Brownian motion with the mean square displacement (MSD linear in time τ and inversly proportional to the effective viscosity of the nematic medium. At shorter times, however, the dynamics is markedly nonlinear with MSD growing more slowly (subdiffusion or faster (superdiffusion than τ. These results are discussed in the context of coupling of colloidal particle's dynamics to the director fluctuation dynamics.

  4. Effect of water table fluctuations on phreatophytic root distribution.

    Science.gov (United States)

    Tron, Stefania; Laio, Francesco; Ridolfi, Luca

    2014-11-07

    The vertical root distribution of riparian vegetation plays a relevant role in soil water balance, in the partition of water fluxes into evaporation and transpiration, in the biogeochemistry of hyporheic corridors, in river morphodynamics evolution, and in bioengineering applications. The aim of this work is to assess the effect of the stochastic variability of the river level on the root distribution of phreatophytic plants. A function describing the vertical root profile has been analytically obtained by coupling a white shot noise representation of the river level variability to a description of the dynamics of root growth and decay. The root profile depends on easily determined parameters, linked to stream dynamics, vegetation and soil characteristics. The riparian vegetation of a river characterized by a high variability turns out to have a rooting system spread over larger depths, but with shallower mean root depths. In contrast, a lower river variability determines root profiles with higher mean root depths. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Contamination due to memory effects in filtered vacuum arc plasma deposition systems

    CERN Document Server

    Martins, D R; Verdonck, P; Brown, I G

    2002-01-01

    Thin film synthesis by filtered vacuum arc plasma deposition is a widely used technique with a number of important emerging technological applications. A characteristic feature of the method is that during the deposition process not only is the substrate coated by the plasma, but the plasma gun itself and the magnetic field coil and/or vacuum vessel section constituting the macroparticle filter are also coated to some extent. If then the plasma gun cathode is changed to a new element, there can be a contamination of the subsequent film deposition by sputtering from various parts of the system of the previous coating species. We have experimentally explored this effect and compared our results with theoretical estimates of sputtering from the SRIM (Stopping and Range of Ions in Matter) code. We find film contamination of order 10-4 - 10-3, and the memory of the prior history of the deposition hardware can be relatively long-lasting.

  6. Effect of vacuum packing and temperature on survival and hatching of strongyle eggs in faecal samples

    DEFF Research Database (Denmark)

    Sengupta, Mita Eva; Thapa, Sundar; Thamsborg, Stig Milan

    2016-01-01

    Strongyle eggs of helminths of livestock usually hatch within a few hours or days after deposition with faeces. This poses a problem when faecal sampling is performed in the field. As oxygen is needed for embryonic development, it is recommended to reduce air supply during transport and refrigerate....... The present study therefore investigated the combined effect of vacuum packing and temperature on survival of strongyle eggs and their subsequent ability to hatch and develop into L3. Fresh faecal samples were collected from calves infected with Cooperia oncophora, pigs infected with Oesophagostomum dentatum......, and horses infected with Strongylus vulgaris and cyathostomins. The samples were allocated into four treatments: vacuum packing and storage at 5 °C or 20 °C (5 V and 20 V); normal packing in plastic gloves closed with a loose knot and storage at 5 °C or 20 °C (5 N and 20 N). The number of eggs per gram...

  7. Contamination due to memory effects in filtered vacuum arc plasma deposition systems

    International Nuclear Information System (INIS)

    Martins, D.R.; Salvadori, M.C.; Verdonck, P.; Brown, I.G.

    2002-01-01

    Thin film synthesis by filtered vacuum arc plasma deposition is a widely used technique with a number of important emerging technological applications. A characteristic feature of the method is that during the deposition process not only is the substrate coated by the plasma, but the plasma gun itself and the magnetic field coil and/or vacuum vessel section constituting the macroparticle filter are also coated to some extent. If then the plasma gun cathode is changed to a new element, there can be a contamination of the subsequent film deposition by sputtering from various parts of the system of the previous coating species. We have experimentally explored this effect and compared our results with theoretical estimates of sputtering from the stopping and range of ions in matter code. We find film contamination of the order of 10 -4 -10 -3 , and the memory of the prior history of the deposition hardware can be relatively long lasting

  8. Contamination due to memory effects in filtered vacuum arc plasma deposition systems

    Energy Technology Data Exchange (ETDEWEB)

    Martins, D.R.; Salvadori, M.C.; Verdonck, P.; Brown, I.G.

    2002-08-13

    Thin film synthesis by filtered vacuum arc plasma deposition is a widely used technique with a number of important emerging technological applications. A characteristic feature of the method is that during the deposition process not only is the substrate coated by the plasma, but the plasma gun itself and the magnetic field coil and/or vacuum vessel section constituting the macroparticle filter are also coated to some extent. If then the plasma gun cathode is changed to a new element, there can be a contamination of the subsequent film deposition by sputtering from various parts of the system of the previous coating species. We have experimentally explored this effect and compared our results with theoretical estimates of sputtering from the SRIM (Stopping and Range of Ions in Matter) code. We find film contamination of order 10-4 - 10-3, and the memory of the prior history of the deposition hardware can be relatively long-lasting.

  9. The effect of vacuum packaging on physicochemical changes in rainbow trout (Oncorhynchus mykiss during cold storage

    Directory of Open Access Journals (Sweden)

    František Ježek

    2014-01-01

    Full Text Available The aim of the study was to monitor changes in selected physical (awwater activity, pH values and chemical (TVBN total volatile basic nitrogen, TMA-N trimethylamine nitrogen, FFA free fatty acids, PV peroxide values, TBA thiobarbituric acid value properties in the shelf life of rainbow trout (Oncorhynchus mykiss muscle. A total of 192 trout were examined. Control samples (96 samples were simply packaged in contact with atmospheric oxygen, while experimental samples (96 samples were packaged in a commercial vacuum (98%. All the samples were stored at 2 ± 2° C for 11 days. Analyses were performed on storage days 1, 2, 4, 7, 9, and 11. During the experiment, aw values increased in both types of packaging (in air: 0.982; vacuum-packaged: 0.989. At the end of storage, TVBN and TMA concentrations were at 28.88 ± 4.42 and 19.28 ± 3.00 g mg·100-1, respectively, in the muscle of vacuum-packaged trout; and at 30.52 ± 2.91 and 19.94 ± 2.05 mg·100 g-1, respectively, in fish in simple packaging. The FFA content in vacuum-packaged fish initially declined before increasing to 3.67 ± 2.37% of total fat as oleic acid later in the experiment. The pattern of PV changes was inconclusive, and significant changes (P -1 in vacuum-packaged fish and to 26.03 ± 8.00 mg·kg-1 in fish in simple packaging. Free fatty acids are not a good indicator of spoilage because they are converted to hydroperoxides. Vacuum packaging effectively slowed down oxidative changes in rainbow trout muscle. The peroxide content is not a suitable indicator of shelf life as peroxides are decomposed to secondary products. Total volatile basic nitrogen and thiobarbituric acid value can be recommended as suitable indicators of freshness and shelf life.

  10. Simulation analysis of within-day flow fluctuation effects on trout below flaming Gorge Dam.

    Energy Technology Data Exchange (ETDEWEB)

    Railsback, S. F.; Hayse, J. W.; LaGory, K. E.; Environmental Science Division; EPRI

    2006-01-01

    In addition to being renewable, hydropower has the advantage of allowing rapid load-following, in that the generation rate can easily be varied within a day to match the demand for power. However, the flow fluctuations that result from load-following can be controversial, in part because they may affect downstream fish populations. At Flaming Gorge Dam, located on the Green River in northeastern Utah, concern has been raised about whether flow fluctuations caused by the dam disrupt feeding at a tailwater trout fishery, as fish move in response to flow changes and as the flow changes alter the amount or timing of the invertebrate drift that trout feed on. Western Area Power Administration (Western), which controls power production on submonthly time scales, has made several operational changes to address concerns about flow fluctuation effects on fisheries. These changes include reducing the number of daily flow peaks from two to one and operating within a restricted range of flows. These changes significantly reduce the value of the power produced at Flaming Gorge Dam and put higher load-following pressure on other power plants. Consequently, Western has great interest in understanding what benefits these restrictions provide to the fishery and whether adjusting the restrictions could provide a better tradeoff between power and non-power concerns. Directly evaluating the effects of flow fluctuations on fish populations is unfortunately difficult. Effects are expected to be relatively small, so tightly controlled experiments with large sample sizes and long study durations would be needed to evaluate them. Such experiments would be extremely expensive and would be subject to the confounding effects of uncontrollable variations in factors such as runoff and weather. Computer simulation using individual-based models (IBMs) is an alternative study approach for ecological problems that are not amenable to analysis using field studies alone. An IBM simulates how a

  11. Numerical and Experimental Investigations of the Effect of PVD and Vacuum Pressure on the Degree of Saturation

    Directory of Open Access Journals (Sweden)

    Ala Nasir Aljorany

    2018-12-01

    Full Text Available Soft clays are generally characterized by low shear strength, low permeability and high compressibility. An effective method to accelerate consolidation of such soils is to use vertical drains along with vacuum preloading to encourage radial flow of water. In this research numerical modeling of prefabricated vertical drains with vacuum pressure was done to investigate the effect of using vertical drains together with vacuum pressure on the degree of saturation of fully and saturated-unsaturated soft soils. Laboratory experiments were conducted by using a specially-designed large consolidometer cell where a central drain was installed and vacuum pressure was applied. All tests were conducted with a vacuum pressure of 40 kPa applied for a period of 30 days where a degree of soil consolidation of 90% was attained. At the end of the test period fifteen samples were taken from different locations distributed along the depth and radially to measure the water content. Consolidation settlements were recorded with time for all tests. The results showed that using vacuum pressure with vertical drains is a very effective method to accelerate consolidation of soils. As the thickness of unsaturated top layer increases, the settlement of soil surface decreases. The water content decreased after 30 days of application of the vacuum pressure.

  12. Coherent charge fluctuations in Josephson junctions and the oscillations of the effective capacitance

    International Nuclear Information System (INIS)

    Krive, I.V.; Rozhavsky, A.S.

    1990-07-01

    We predict novel voltage oscillations of the effective capacitance of small Josephson junctions. This macroscopic effect involves coherent charge fluctuations with charge 2e, leading to a period of oscillations, V c = 2e/C, where C is the junction capacitance. The amplitude of the effect decreases with temperature as exp(-π 2 T/ε c ), where ε c = (2e) 2 /C. (author). 6 refs

  13. Effects of fluctuating temperature and food availability on reproduction and lifespan.

    Science.gov (United States)

    Schwartz, Tonia S; Pearson, Phillip; Dawson, John; Allison, David B; Gohlke, Julia M

    2016-12-15

    Experimental studies on energetics and aging often remove two major factors that in part regulate the energy budget in a normal healthy individual: reproduction and fluctuating environmental conditions that challenge homeostasis. Here we use the cyclical parthenogenetic Daphnia pulex to evaluate the role of a fluctuating thermal environment on both reproduction and lifespan across six food concentrations. We test the hypotheses that (1) caloric restriction extends lifespan; (2) maximal reproduction will come with a cost of shortened lifespan; and (3) at a given food concentration, relative to a metabolically equivalent constant temperature environment a diel fluctuating thermal environment will alter the allocation of energy to reproduction and lifespan to maintain homeostasis. We did not identify a level of food concentration that extended lifespan in response to caloric restriction, and we found no cost of reproduction in terms of lifespan. Rather, the individuals at the highest food levels generally had the highest reproductive output and the longest lifespans, the individuals at the intermediate food level decreased reproduction and maintained lifespan, and the individuals at the three lower food concentrations had a decrease in reproduction and lifespan as would be predicted with increasing levels of starvation. Fluctuating temperature had no effect on lifespan at any food concentration, but delayed time to reproductive maturity and decreased early reproductive output at all food concentrations. This suggests that a fluctuating temperature regimen activates molecular pathways that alter energy allocation. The costs of fluctuating temperature on reproduction were not consistent across the lifespan. Statistical interactions for age of peak reproduction and lifetime fecundity suggest that senescence of the reproductive system may vary between temperature regimens at the different food concentrations. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Effect of vacuum and temperature on the mechanical properties of an aramid/epoxy composite

    International Nuclear Information System (INIS)

    Hahn, H.T.; Chin, W.K.

    1981-01-01

    The mechanical properties of a Kevlar 49/epoxy composite intended for flywheel applications are investigated in the laboratory and simulated service environments. The filament-wound composites were preconditioned in the test environment for 1-5 months, during which weight change was monitored, then subjected to tensile and fatigue tests at room temperature or 75 deg in vacuum. A weight loss of only 1.63% is observed after 11 months in the simulated service environment, most of which is attributed to moisture desorbed in vacuum. In contrast to air at 75 C, the simulated service environment is also found to produce no deleterious effects on static and fatigue strengths, probably to moisture desorption and a lack of oxidation. A fatigue life of about 100,000 cycles for 95% survival proability is obtained at 70% of the average static strength, and the macroscopic failure mode, which results in a brush-like formation, is observed to be independent of the type of loading and preconditioning. It is concluded that an environment of 75 C in vacuum is no deterrent to the application of the composite in flywheels, however the possibility of increasing service temperature to 150 C should be investigated

  15. Effect of gravity on false-vacuum decay rates for O(4)-symmetric bubble nucleation

    International Nuclear Information System (INIS)

    Samuel, D.A.; Hiscock, W.A.

    1991-01-01

    The self-gravity of quantum fields is often considered to be a negligible perturbation upon a background spacetime and not of much physical interest. Its importance is determined by the ratio of the mass of the field to the Planck mass, this ratio being very small for those fields that we are most familiar in dealing with. However, it is conceivable that either in the very early Universe or even today a false-vacuum decay could occur associated with a field of appreciable mass. The effect of self-gravity upon false-vacuum decay was initially studied within the ''thin-wall'' approximation by Coleman and De Luccia. Their analysis involved the approximate solution of the coupled Euclideanized field and Einstein equations with the assumption of O(4)-symmetric bubble nucleation. In this paper we consider the range of validity of the ''thin-wall'' approximation by comparing the Coleman--De Luccia results with exact numerical results for a quartic polynomial potential. We also extend the analysis into regimes for which the ''thin-wall'' approximation is inapplicable. In the case of an initially de Sitter space decaying into Minkowski space, we find a smooth transition between the Coleman--De Luccia mode of bubble formation and the Hawking-Moss transition, wherein the entire spacetime tunnels ''at once'' to the maximum of the potential. In the case of the decay of an initially Minkowski space to an anti--de Sitter space, we find that there is a ''forbidden region'' of vacuum potential parameters for which decay is not possible. At energies far below the Planck scale, the boundary of this region is accurately described by the thin-wall prediction obtained by Coleman and De Luccia. At energies near the Planck scale, however, the actual ''forbidden region'' is significantly smaller than predicted by the thin-wall approximation; thus, vacuum decays are possible which appear to be forbidden by thin-wall calculations

  16. Anti-cellulite and slimming effect of vacuum massage - a case study

    Directory of Open Access Journals (Sweden)

    Anna Baryluk

    2017-11-01

    noted during the third measurement, after a series of 10 treatments. Visually, the cellulite decreased. Within 10 days after treatment cessation the effect of the reduced cellulite was satisfactory, but the thighs circuits measurements obtained the same value as it was before treatment. Based on the case description one can assume that the vacuum massage reduces the cellulite and also the body fat. The success of this massage is effective only with the systematic performance. An important factor is the intensity of performing the treatment, a prior preparation of the skin, and also an appropriate diet. In order to assess the effectiveness of vacuum massage there should be studies carried out on a larger number of patients.

  17. [Effects of vacuum sealing drainage technique in acute and chronic suppurative tenosynovitis of hand].

    Science.gov (United States)

    Wang, H; Xia, F; Xing, D M; Ren, D; Feng, W; Chen, Y; Xiao, Z H; Zhao, Z M

    2017-05-01

    Objective: To investigate the effects of vacuum sealing drainage technique in acute and chronic suppurative tenosynovitis of hand. Methods: A total of 9 cases acute and chronic suppurative tenosynovitis patients from January 2013 to April 2015 in Puai Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology were retrospectively reviewed. There were 6 males and 3 females, aging from 27 to 65 years, the average age was 55 years. There were 3 cases of index finger, 3 cases of middle finger, 2 cases of ring finger, 1 case include three fingers. The infection causes included stabbing with fishbone in 3 cases, stabbing with animal bone fragments in 3 cases, wound by sawdust in 3 cases, meat grinder injury in 1 case, multiple fingers crush injury postoperative infection of garbage truck in 1 case. Bacterial infection included 2 cases with Staphylococcus aureus, 2 cases with Staphylococcus epidermidis, 1 case with normal Escherichia coli, 1 case with mixed infection of Enterobacter aerogenes, Klebsiella oxytoca and Staphylococcus, 1 case with Bauman Acinetobacter bacillus, 1 case with Proteus mirabilis and 1 case of no growth of pathogenic bacteria culture. After thorough debridement, vacuum sealing drainage was used to observe the characteristics of irrigation fluid, the formation of cavity inflammation, the prognosis of infection and the recovery of finger function. Results: Seven patients with suppurative tenosynovitis were treated for 7 to 14 days, replaced the vacuum sealing drainage dressing once; 1 patient was an illustration of the finger tip defect flap infected patients after 21 days of treatment, replaced the vacuum sealing drainage dressing twice, 1 patient was an illustration of the central refers to trauma, postoperative infection patients 28 d, replaced three times in the VSD. The follow-up time was 3 to 12 months (mean 8.2 months), 7 patients without tendon necrosis, secondary suture with no infection, 2 cases of

  18. Finding evidence for density fluctuation effects on electron cyclotron heating deposition profiles on DIII-D

    International Nuclear Information System (INIS)

    Brookman, M. W.; Austin, M. E.; Petty, C. C.

    2015-01-01

    Theoretical work, computation, and results from TCV [J. Decker “Effect of density fluctuations on ECCD in ITER and TCV,” EPJ Web of Conf. 32, 01016 (2012)] suggest that density fluctuations in the edge region of a tokamak plasma can cause broadening of the ECH deposition profile. In this paper, a GUI tool is presented which is used for analysis of ECH deposition as a first step towards looking for this broadening, which could explain effects seen in previous DIII-D ECH transport studies [K.W. Gentle “Electron energy transport inferences from modulated electron cyclotron heating in DIII-D,” Phys. Plasmas 13, 012311 (2006)]. By applying an FFT to the T e measurements from the University of Texas’s 40-channel ECE Radiometer, and using a simplified thermal transport equation, the flux surface extent of ECH deposition is determined. The Fourier method analysis is compared with a Break-In-Slope (BIS) analysis and predictions from the ray-tracing code TORAY. Examination of multiple Fourier harmonics and BIS fitting methods allow an estimation of modulated transport coefficients and thereby the true ECH deposition profile. Correlations between edge fluctuations and ECH deposition in legacy data are also explored as a step towards establishing a link between fluctuations and deposition broadening in DIII-D

  19. Finding evidence for density fluctuation effects on electron cyclotron heating deposition profiles on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Brookman, M. W., E-mail: brookmanmw@fusion.gat.com; Austin, M. E. [Institute for Fusion Studies, University of Texas at Austin, MS 13-505, 3483 Dunhill St, San Diego, CA 92121-1200 (United States); Petty, C. C. [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States)

    2015-12-10

    Theoretical work, computation, and results from TCV [J. Decker “Effect of density fluctuations on ECCD in ITER and TCV,” EPJ Web of Conf. 32, 01016 (2012)] suggest that density fluctuations in the edge region of a tokamak plasma can cause broadening of the ECH deposition profile. In this paper, a GUI tool is presented which is used for analysis of ECH deposition as a first step towards looking for this broadening, which could explain effects seen in previous DIII-D ECH transport studies [K.W. Gentle “Electron energy transport inferences from modulated electron cyclotron heating in DIII-D,” Phys. Plasmas 13, 012311 (2006)]. By applying an FFT to the T{sub e} measurements from the University of Texas’s 40-channel ECE Radiometer, and using a simplified thermal transport equation, the flux surface extent of ECH deposition is determined. The Fourier method analysis is compared with a Break-In-Slope (BIS) analysis and predictions from the ray-tracing code TORAY. Examination of multiple Fourier harmonics and BIS fitting methods allow an estimation of modulated transport coefficients and thereby the true ECH deposition profile. Correlations between edge fluctuations and ECH deposition in legacy data are also explored as a step towards establishing a link between fluctuations and deposition broadening in DIII-D.

  20. Stochastic dark energy from inflationary quantum fluctuations

    Science.gov (United States)

    Glavan, Dražen; Prokopec, Tomislav; Starobinsky, Alexei A.

    2018-05-01

    We study the quantum backreaction from inflationary fluctuations of a very light, non-minimally coupled spectator scalar and show that it is a viable candidate for dark energy. The problem is solved by suitably adapting the formalism of stochastic inflation. This allows us to self-consistently account for the backreaction on the background expansion rate of the Universe where its effects are large. This framework is equivalent to that of semiclassical gravity in which matter vacuum fluctuations are included at the one loop level, but purely quantum gravitational fluctuations are neglected. Our results show that dark energy in our model can be characterized by a distinct effective equation of state parameter (as a function of redshift) which allows for testing of the model at the level of the background.

  1. Magnetically induced vacuum decay

    International Nuclear Information System (INIS)

    Xue Shesheng

    2003-01-01

    We study the fermionic vacuum energy of vacua with and without application of an external magnetic field. The energetic difference of two vacua leads to the vacuum decaying and the vacuum energy being released. In the context of quantum field theories, we discuss why and how the vacuum energy can be released by spontaneous photon emission and/or paramagnetically screening the external magnetic field. In addition, we quantitatively compute the vacuum energy released, the paramagnetic screening effect, and the rate and spectrum of spontaneous photon emission. The possibilities of experimentally detecting such an effect of vacuum-energy release and that this effect accounts for the anomalous x-ray pulsar are discussed

  2. Effects of pressure fluctuations on the combustion process in turbulent premixed flames

    Science.gov (United States)

    Beardsell, Guillaume; Lapointe, Simon; Blanquart, Guillaume

    2016-11-01

    The need for a thorough understanding of turbulence-combustion interactions in compressible flows is driven by recent technological developments in propulsion as well as renewed interest in the development of next generation supersonic and hypersonic vehicles. In such flows, pressure fluctuations displaying a wide range of length and timescales are present. These fluctuations are expected to impact the combustion process to varying degrees, depending amongst other things on the amplitude of the pressure variations and the timescales of the chemical reactions taking place in the flame. In this context, numerical simulations of these flows can provide insight into the impact of pressure fluctuations on the combustion process. In the present work, we analyze data from simulations of statistically-flat premixed n-heptane/air flames at high Karlovitz numbers. The compressible Navier-Stokes equations are solved exactly (DNS) and results obtained with both detailed kinetic modeling and one-step chemistry are considered. The effects of pressure fluctuations on the fuel burning rate are investigated. The findings are compared with results obtained from simulations of one-dimensional premixed flames subjected to various pressure waves.

  3. Effect of vacuum and of strong adsorbed water films on micropore formation in aluminum hydroxide xerogel powders.

    Science.gov (United States)

    Beruto, Dario T; Botter, Rodolfo; Converti, Attilio

    2009-02-01

    Aluminum hydroxide gels were washed with water, ethanol, methanol and isopropanol to obtain new gels with different liquid phases that were dried either in air at 120 degrees C or under vacuum at 80 degrees C. Drying in air leads to alcoholic xerogels with BET surface areas larger than the aqueous ones. The effect of the alcoholic groups as substitutes of the hydroxyl ones has been discussed to account for the final size of xerogel crystallites. Drying under vacuum decreases the BET surface of the methanol xerogels, but no micropores are formed in all the alcoholic xerogel matrixes. On the contrary, the vacuum drying process changes significantly the microstructure of the aqueous xerogels. Their BET surface increases by 34 m(2)/g, and micropores are formed within their crystallite aggregates. It has been experimentally shown that these changes are due to a shear transformation that occurs in the boehmite xerogels obtained under vacuum. To discuss these data, the existence of chemical compounds such as AlOOHnH(2)O was postulated. On this ground, a neat analogy between vacuum drying process and vacuum interfacial decomposition reactions of inorganic salts can be drawn. This analogy explains how a state of stresses forms in aqueous xerogel matrix during vacuum drying process.

  4. Density Fluctuation in Aqueous Solutions and Molecular Origin of Salting-Out Effect for CO2

    International Nuclear Information System (INIS)

    Ho, Tuan Anh; Ilgen, Anastasia

    2017-01-01

    Using molecular dynamics simulation, we studied the density fluctuations and cavity formation probabilities in aqueous solutions and their effect on the hydration of CO 2 . With increasing salt concentration, we report an increased probability of observing a larger than the average number of species in the probe volume. Our energetic analyses indicate that the van der Waals and electrostatic interactions between CO 2 and aqueous solutions become more favorable with increasing salt concentration, favoring the solubility of CO 2 (salting in). However, due to the decreasing number of cavities forming when salt concentration is increased, the solubility of CO 2 decreases. The formation of cavities was found to be the primary control on the dissolution of gas, and is responsible for the observed CO 2 salting-out effect. Finally, our results provide the fundamental understanding of the density fluctuation in aqueous solutions and the molecular origin of the salting-out effect for real gas.

  5. The Effect of Quark Mass and α-α Term on qq Condensation in QCD Vacuum

    Institute of Scientific and Technical Information of China (English)

    YANG Sheng-Dong; ZHOU Zhi-Ning; YANG Ze-Sen

    2001-01-01

    Beginning with the QCD Lagrangian in the global color symmetry model, we have derived a Hamiltonian including the lowest order current-current coupling. Taking instantaneous quadratic interaction kernel and using the Bogoliubov-Valatin transformation, we have got an effective Hamiltonian for computation. This Hamiltonian is similar to that introduced by Le Yaouanc et al., except that the α-α term has been considered here. We calculated the qq condensation in the BCS type of vacuum with quark mass and α-α term included. Our calculation shows that the value of qq condensation has increased by at least 10% with the α-α term included.``

  6. Salting by vacuum brine impregnation in nitrite-free lonza: effect on Enterobacteriaceae

    Directory of Open Access Journals (Sweden)

    Annalisa Serio

    2017-01-01

    Full Text Available Lonza is a traditional Italian meat product made from whole pork muscles, which is typically cured by dry salting. In this work, we study the effects of vacuum brine impregnation (VBI as an alternative salting method on the survival of Enterobacteriaceae, in presence and in absence of nitrites. In comparison with the traditional brining process, VBI contributed to reducing the Enterobacteriaceae population on product surface but induced contamination of the inner muscle tissues. Our results suggest that the species isolated became adapted to processing conditions, and salt tolerance was species- or straindependent. This result is of particular importance for future applications of VBI in lonza manufacturing.

  7. Salting by Vacuum Brine Impregnation in Nitrite-Free Lonza: Effect on Enterobacteriaceae.

    Science.gov (United States)

    Serio, Annalisa; Chaves-López, Clemencia; Rossi, Chiara; Pittia, Paola; Rosa, Marco Dalla; Paparella, Antonello

    2017-01-24

    Lonza is a traditional Italian meat product made from whole pork muscles, which is typically cured by dry salting. In this work, we study the effects of vacuum brine impregnation (VBI) as an alternative salting method on the survival of Enterobacteriaceae, in presence and in absence of nitrites. In comparison with the traditional brining process, VBI contributed to reducing the Enterobacteriaceae population on product surface but induced contamination of the inner muscle tissues. Our results suggest that the species isolated became adapted to processing conditions, and salt tolerance was species- or strain-dependent. This result is of particular importance for future applications of VBI in lonza manufacturing.

  8. Effectiveness of solid lubricant coatings for friction in hard vacuum (10-9 tor)

    Science.gov (United States)

    Verkin, B. I.; Lyubraskiy, I. M.; Udovenko, V. F.; Sentyurikhina, L. N.

    1974-01-01

    A study was made of the efficiency of solid lubricating coatings, based on MoS2 with various binders, during friction and under highvacuum conditions. Mass spectrometry was used for an analysis of the composition of the gas evolved from the coatings in the friction process. It is shown that the vacuum level, loading, and sliding velocity influence coating effectiveness. In the friction process the solid lubricant coatings yield characteristic decay products associated with the chemical nature of the binders. The mechanism of coating breakdown during friction is associated with the binder breakdown mechanism.

  9. Vacuum instability, anomalous asymmetry effect, phase transition and band mixing in strongly deformed nuclei

    International Nuclear Information System (INIS)

    Lin, L.; Sperber, D.

    1976-01-01

    In two recent papers the instability of the quasi-particle vacuum was related to the high-spin anomaly in rotational nuclear states. The direct consequence of this fact is that the system will make a ''phase transition'' under that situation. Studying the induced rotational asymmetry effect, in the present paper another theoretical fact is discussed, which support this ''phase transition''. Furthermore, it is shown that when this ''phase transition'' occurs, in order to have a proper description of the system, a modification of the physical ground state is necessary which suggests a microscopic theory of band mixing for high spin anomaly in rotational nuclear states

  10. Effects of stratification and fluctuations on sound propagation in the deep ocean

    International Nuclear Information System (INIS)

    March, R.H.

    1979-01-01

    It is noted that even in a homogeneous ocean, the effects of non-thermal noise and sound absorption limit the maximum effective range of detection of acoustic signals from particle cascades to distances of 2 to 10 kilometers, depending on the surface conditions prevailing and the directional characteristics of the detector. In the present paper, the effects of stratification and fluctuations in the sound velocity profile in the deep ocean over distances of this order are examined. Attention is given to two effects of potential significance, refraction and scintillation. It is found that neither effect has any significant consequences at ranges of less than 10 km

  11. Thermal blurring effects on fluctuations of conserved charges in rapidity space

    Energy Technology Data Exchange (ETDEWEB)

    Asakawa, M.; Kitazawa, M.; Onishi, Y.; Sakaida, M.

    2016-12-15

    We argue that the diffusion in the hadron phase and the thermal blurring at thermal freezeout affect observed conserved charge fluctuations considerably in relativistic heavy ion collisions, and show that their effects are of similar order at RHIC and LHC, and thus equally important in understanding experimental data. We also argue that, in order to disentangle them and obtain the initial state charge fluctuations, which we are interested in, it is crucial to measure their dependence on the rapidity window size. In the energy range of the beam energy scan program at RHIC, the diffusion effect would be less important because of the shorter duration of the hadron phase, but the importance of thermal blurring is not reduced. In addition, it is necessary to take account of the complex correspondence between the space-time rapidity and rapidity of observed particles, there.

  12. Size scaling effects on the particle density fluctuations in confined plasmas

    International Nuclear Information System (INIS)

    Vazquez, Federico; Markus, Ferenc

    2009-01-01

    In this paper, memory and nonlocal effects on fluctuating mass diffusion are addressed in the context of fusion plasmas. Nonlocal effects are included by considering a diffusivity coefficient depending on the size of the container in the transverse direction to the applied magnetic field. It is obtained by resorting to the general formulation of the extended version of irreversible thermodynamics in terms of the higher order dissipative fluxes. The developed model describes two different types of the particle density time correlation function. Both have been observed in tokamak and nontokamak devices. These two kinds of time correlation function characterize the wave and the diffusive transport mechanisms of particle density perturbations. A transition between them is found, which is controlled by the size of the container. A phase diagram in the (L,2π/k) space describes the relation between the dynamics of particle density fluctuations and the size L of the system together with the oscillating mode k of the correlation function.

  13. Effects of water compressibility on the pressure fluctuation prediction in pump turbine

    International Nuclear Information System (INIS)

    Yin, J L; Wang, D Z; Wang, L Q; Wu, Y L; Wei, X Z

    2012-01-01

    The compressible effect of water is a key factor in transient flows. However, it is always neglected in the unsteady simulations for hydraulic machinery. In light of this, the governing equation of the flow is deduced to combine the compressibility of water, and then simulations with compressible and incompressible considerations to the typical unsteady flow phenomenon (Rotor stator interaction) in a pump turbine model are carried out and compared with each other. The results show that water compressibility has great effects on the magnitude and frequency of pressure fluctuation. As the operating condition concerned, the compressibility of water will induce larger pressure fluctuation, which agrees better with measured data. Moreover, the lower frequency component of the pressure signal can only be captured with the combination of water compressibility. It can be concluded that water compressibility is a fatal factor, which cannot be neglected in the unsteady simulations for pump turbines.

  14. Initial density fluctuations effects on the microphase separation in ramified polymer mixture

    Energy Technology Data Exchange (ETDEWEB)

    Ghaouar, N. [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire 2092 (Tunisia) and Institut National des Sciences Appliquees et de Technologie, INSAT, Centre Urbain Nord, BP. 676, Tunis (Tunisia)]. E-mail: naoufel-ghaouar@lycos.com

    2007-02-19

    Our study focuses on the initial density fluctuations effects on microphase separation in ramified polymer mixture. For this purpose, we introduce a screening length {kappa} by considering the condition that the scattered intensity should not be changed by cross-linking. We recover that {kappa}{sup 2}{approx}C/({chi}-{chi}{sub i}), where C is the rigidity constant of the network and {chi} the Flory parameter. Three regimes versus the temperature of the mixture are discussed. The kinetics of the microphase separation is also studied through the relaxation rate. The derived relaxation rate evolution relative to ramified polymers mixture must be compared to that relative to a linear polymer mixture. Finally, we discuss the solvent effect on the microphase separation and we show that the initial fluctuations have little importance because of the excluded volume interaction.

  15. Searching for gluon number fluctuations effects in eA collisions

    Energy Technology Data Exchange (ETDEWEB)

    Kugeratski, M. S. [Universidade Federal de Santa Catarina, Campus Joinville, Rua Presidente Prudente de Moraes, 406, CEP 89218-000, Joinville, SC (Brazil); Gonçalves, V. P.; Santana Amaral, J. T. de [Instituto de Física e Matemática, Universidade Federal de Pelotas, Caixa Postal 354, CEP 96010-900, Pelotas, RS (Brazil)

    2014-11-11

    We propose to investigate the gluon number fluctuations effects in deep inelastic electron-ion scattering at high energies. We estimate the nuclear structure function F{sub 2}{sup A}(x,Q{sup 2}), as well the longitudinal and charm contributions, using a generalization for nuclear targets of the Golec-Biernat-Wusthoff (GBW) model which describes the electron proton HERA data. Here we consider that the nucleus at high energies acts as an amplifier of the physics of high parton densities. For a first investigation we study the scattering with Ca and Pb nuclei. Our preliminary results predict that the effects of gluon number fluctuations are small in the region of the future electron ion collider.

  16. Hanle effect in (In,Ga)As quantum dots: Role of nuclear spin fluctuations

    OpenAIRE

    Kuznetsova, M. S.; Flisinski, K.; Gerlovin, I. Ya.; Ignatiev, I. V.; Kavokin, K. V.; Verbin, S. Yu.; Yakovlev, D. R.; Reuter, D.; Wieck, A. D.; Bayer, M.

    2013-01-01

    The role of nuclear spin fluctuations in the dynamic polarization of nuclear spins by electrons is investigated in (In,Ga)As quantum dots. The photoluminescence polarization under circularly polarized optical pumping in transverse magnetic fields (Hanle effect) is studied. A weak additional magnetic field parallel to the optical axis is used to control the efficiency of nuclear spin cooling and the sign of nuclear spin temperature. The shape of the Hanle curve is drastically modified with cha...

  17. The Effect of Exchange Rate Fluctuations on a Trade Balance, the case of Russia.

    OpenAIRE

    Masliukova, Tatiana

    2014-01-01

    This thesis examines the impact of exchange rate fluctuation on trade balance. In order to examine the effect of depreciation of domestic currency on the trade balance, the data for Russian Federation was used. The time series analysis includes quarterly data since 2000 till 2014. With help of cointegration model it was concluded that there is a long-term dependence between exchange rate and trade balance. Regression results suggest that the impact of depreciation of national currency on trad...

  18. A scheme of measurement of quantum-vacuum geometric phases in a noncoplanar fibre system

    International Nuclear Information System (INIS)

    Shen Jianqi

    2004-01-01

    We study the quantum-vacuum geometric phases resulting from the vacuum fluctuation of photon fields in a Tomita-Chiao-Wu noncoplanar curved fibre system, and suggest a scheme to test for the potential existence of such a vacuum effect. Since the signs of the quantum-vacuum geometric phases of left- and right-handed (LRH) circularly polarized light are opposite, the sum of the geometric phases at the vacuum level is necessarily zero in the fibre experiments performed previously by other authors. By using the present approach where a fibre made of gyroelectric media is employed, the quantum-vacuum geometric phases of LRH light cannot be exactly cancelled, and it may therefore be possible to test this experimentally. (letter to the editor)

  19. Density fluctuation effects on collective neutrino oscillations in O-Ne-Mg core-collapse supernovae

    International Nuclear Information System (INIS)

    Cherry, John F.; Fuller, George M.; Wu Mengru; Qian Yongzhong; Carlson, J.; Duan Huaiyu

    2011-01-01

    We investigate the effect of matter density fluctuations on supernova collective neutrino flavor oscillations. In particular, we use full multiangle, three-flavor, self-consistent simulations of the evolution of the neutrino flavor field in the envelope of an O-Ne-Mg core-collapse supernova at shock breakout (neutronization neutrino burst) to study the effect of the matter density ''bump'' left by the He-burning shell. We find a seemingly counterintuitive increase in the overall ν e survival probability created by this matter density feature. We discuss this behavior in terms of the interplay between the matter density profile and neutrino collective effects. While our results give new insights into this interplay, they also suggest an immediate consequence for supernova neutrino burst detection: it will be difficult to use a burst signal to extract information on fossil burning shells or other fluctuations of this scale in the matter density profile. Consistent with previous studies, our results also show that the interplay of neutrino self-coupling and matter fluctuation could cause a significant increase in the ν e survival probability at very low energy.

  20. The hydrodynamic basis of the vacuum cleaner effect in continuous-flow PCNL instruments: an empiric approach and mathematical model.

    Science.gov (United States)

    Mager, R; Balzereit, C; Gust, K; Hüsch, T; Herrmann, T; Nagele, U; Haferkamp, A; Schilling, D

    2016-05-01

    Passive removal of stone fragments in the irrigation stream is one of the characteristics in continuous-flow PCNL instruments. So far the physical principle of this so-called vacuum cleaner effect has not been fully understood yet. The aim of the study was to empirically prove the existence of the vacuum cleaner effect and to develop a physical hypothesis and generate a mathematical model for this phenomenon. In an empiric approach, common low-pressure PCNL instruments and conventional PCNL sheaths were tested using an in vitro model. Flow characteristics were visualized by coloring of irrigation fluid. Influence of irrigation pressure, sheath diameter, sheath design, nephroscope design and position of the nephroscope was assessed. Experiments were digitally recorded for further slow-motion analysis to deduce a physical model. In each tested nephroscope design, we could observe the vacuum cleaner effect. Increase in irrigation pressure and reduction in cross section of sheath sustained the effect. Slow-motion analysis of colored flow revealed a synergism of two effects causing suction and transportation of the stone. For the first time, our model showed a flow reversal in the sheath as an integral part of the origin of the stone transportation during vacuum cleaner effect. The application of Bernoulli's equation provided the explanation of these effects and confirmed our experimental results. We widen the understanding of PCNL with a conclusive physical model, which explains fluid mechanics of the vacuum cleaner effect.

  1. Effects of density gradients and fluctuations at the plasma edge on ECEI measurements at ASDEX Upgrade

    Science.gov (United States)

    Vanovac, B.; Wolfrum, E.; Denk, S. S.; Mink, F.; Laggner, F. M.; Birkenmeier, G.; Willensdorfer, M.; Viezzer, E.; Hoelzl, M.; Freethy, S. J.; Dunne, M. G.; Lessig, A.; Luhmann, N. C., Jr.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

    2018-04-01

    Electron cyclotron emission imaging (ECEI) provides measurements of electron temperature (T e ) and its fluctuations (δT e ). However, when measuring at the plasma edge, in the steep gradient region, radiation transport effects must be taken into account. It is shown that due to these effects, the scrape-off layer region is not accessible to the ECEI measurements in steady state conditions and that the signal is dominated by the shine-through emission. Transient effects, such as filaments, can change the radiation transport locally, but cannot be distinguished from the shine-through. Local density measurements are essential for the correct interpretation of the electron cyclotron emission, since the density fluctuations influence the temperature measurements at the plasma edge. As an example, a low frequency 8 kHz mode, which causes 10%-15% fluctuations in the signal level of the ECEI, is analysed. The same mode has been measured with the lithium beam emission spectroscopy density diagnostic, and is very well correlated in time with high frequency magnetic fluctuations. With radiation transport modelling of the electron cyclotron radiation in the ECEI geometry, it is shown that the density contributes significantly to the radiation temperature (T rad) and the experimental observations have shown the amplitude modulation in both density and temperature measurements. The poloidal velocity of the low frequency mode measured by the ECEI is 3 km s-1. The calculated velocity of the high frequency mode measured with the magnetic pick-up coils is about 25 km s-1. Velocities are compared with the E × B background flow velocity and possible explanations for the origin of the low frequency mode are discussed.

  2. Substrate Effect on Carbon/Ceramic Mixed Matrix Membrane Prepared by a Vacuum-Assisted Method for Desalination

    Directory of Open Access Journals (Sweden)

    Yingjun Song

    2018-05-01

    Full Text Available This work investigates the effect of various membrane substrates and coating conditions on the formation of carbon/ceramic mixed matrix membranes for desalination application. The substrates were impregnated with phenolic resin via a vacuum-assisted method followed by carbonization under an inert gas. Substrates with pore sizes of 100 nm required a single impregnation step only, where short vacuum times (<120 s resulted in low quality membranes with defects. For vacuum times of ≥120 s, high quality membranes with homogeneous impregnation were prepared leading to high salt rejection (>90% and high water fluxes (up to 25 L m−2 h−1. The increase in water flux as a function of the vacuum time confirms the vacuum etching effect resulting from the vacuum-assisted method. Substrates with pore sizes of 140 nm required two impregnation steps. These pores were too large for the ceramic inter-particle space to be filled with phenolic resin via a single step. In the second impregnation step, increasing the concentration of the phenolic resin resulted in membranes with lower water fluxes. These results indicate that thicker films were formed by increasing the phenolic resin concentration. In the case of substrates with pores of 600 nm, these pores were too large and inter-particle space filling with phenolic resin was not attained.

  3. Near field plasmonic gradient effects on high vacuum tip-enhanced Raman spectroscopy.

    Science.gov (United States)

    Fang, Yurui; Zhang, Zhenglong; Chen, Li; Sun, Mengtao

    2015-01-14

    Near field gradient effects in high vacuum tip-enhanced Raman spectroscopy (HV-TERS) are a recent developing ultra-sensitive optical and spectral analysis technology on the nanoscale, based on the plasmons and plasmonic gradient enhancement in the near field and under high vacuum. HV-TERS can not only be used to detect ultra-sensitive Raman spectra enhanced by surface plasmon, but also to detect clear molecular IR-active modes enhanced by strongly plasmonic gradient. Furthermore, the molecular overtone modes and combinational modes can also be experimentally measured, where the Fermi resonance and Darling-Dennison resonance were successfully observed in HV-TERS. Theoretical calculations using electromagnetic field theory firmly supported experimental observation. The intensity ratio of the plasmon gradient term over the linear plasmon term can reach values greater than 1. Theoretical calculations also revealed that with the increase in gap distance between tip and substrate, the decrease in the plasmon gradient was more significant than the decrease in plasmon intensity, which is the reason that the gradient Raman can be only observed in the near field. Recent experimental results of near field gradient effects on HV-TERS were summarized, following the section of the theoretical analysis.

  4. Quantum vacuum effects on the final fate of a collapsing ball of dust

    Energy Technology Data Exchange (ETDEWEB)

    Arfaei, Hessamaddin [Department of Physics, Sharif University of Technology,P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences(IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Noorikuhani, Milad [Department of Physics, Sharif University of Technology,P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of)

    2017-02-24

    We consider the quantum vacuum effects of the massless scalar fields that are non-minimally coupled to the background geometry of a collapsing homogeneous ball of dust. It is shown that for a definite range of coupling constants, there are repulsive quantum vacuum effects, capable of stopping the collapse process inside the black hole and precluding the formation of singularity. The final fate of the collapse will be a black hole with no singularity, inside which the matter stays balanced. The density of the final static matter will be close to the Planck density. We show that the largest possible radius of the stable static ball inside a black hole with Schwarzschild mass M is given by ((1/(90π))(M/(m{sub p}))){sup (1/3)}ℓ{sub p}. If the black hole undergoes Hawking radiation, the final state will be an extremal quantum-corrected black hole, with zero temperature, with a remnant of matter inside. We show that the resolution of singularity is not disrupted under Hawking radiation.

  5. Anti-Zeno-effect recovery and Lamb-shift modification in modified vacuum

    International Nuclear Information System (INIS)

    Wang Dawei; Wang Ligang; Li Zhenghong; Zhu Shiyao

    2009-01-01

    The influence of the modification of the free vacuum on the quantum Zeno and anti-Zeno effects, as well as the Lamb (energy) shift of a multilevel atom, is studied. A unitary transformation method has been used to include the counter-rotating terms and to obtain the ground state of the whole Hamiltonian. The anti-Zeno effect is recovered if the modified density of states (DOS) has a dip near the transition frequency. The modification of DOS by a dip or a peak will change the Lamb shift compared with that in the free vacuum. Together with our unitary transformation method, there are three different methods to obtain the change in the Lamb shift. Using our method we investigate the change in the Lamb shift and obtain a formula for the change, which is the same as obtained with the method of Louisell [Quantum Statistical Properties of Radiation (Wiley, New York, 1973)] but different from the method of Cohen-Tannoudji et al. [Atom-Photon Interactions: Basic Processes and Applications (Wiley, New York, 1992), pp. 317 and 417]. The correctness of the Lamb shift formulas obtained by the three methods can be easily testified experimentally.

  6. Effect of thermodynamic fluctuations of magnetization on the bound magnetic polaron state in ferromagnetic semiconductors

    International Nuclear Information System (INIS)

    Bednarski, Henryk; Spałek, Józef

    2014-01-01

    We extend the theory of the bound magnetic polaron (BMP) in diluted paramagnetic semiconductors to the situation with a ferromagnetic phase transition. This is achieved by including the classical Gaussian fluctuations of magnetization from the quartic (non-Gaussian) term in the effective Ginzburg–Landau Hamiltonian for the spins. Within this approach, we find a ferromagnetically ordered state within the BMP in the temperature range well above the Curie temperature for the host magnetic semiconductor. Numerical results are compared directly with the recently available experimental data for the ferromagnetic semiconductor GdN. The agreement is excellent, given the simplicity of our model, and is because the polaron size (≃1.4 nm) encompasses a relatively large but finite number (N≈400) of quasiclassical spins S=7/2 coming from Gd 3+ ions. The presence of BMP invalidates the notion of critical temperature and thus makes the incorporation of classical Gaussian fluctuations sufficient to realistically describe the situation. (paper)

  7. The effect on stellarator neoclassical transport of a fluctuating electrostatic spectrum

    International Nuclear Information System (INIS)

    Mynick, H.E.; Boozer, A.H.

    2005-01-01

    A study is presented of the effect on neoclassical transport of a fluctuating electrostatic spectrum, such as produced either by plasma turbulence, or imposed externally. For tokamaks, it is usually assumed that the neoclassical and 'anomalous' contributions to the transport roughly superpose, D=D nc +D an , an intuition also used in modeling stellarators. An alternate intuition, however, is one where it is the collisional and anomalous scattering frequencies which superpose, ν ef =ν+ν an . For nonaxisymmetric systems, in regimes where ∂D/∂ν ef picture' implies that turning on the fluctuations can decrease the total radial transport. Using numerical and analytic means, it is found that the total transport has contributions conforming to each of these intuitions, either of which can dominate. In particular, for stellarators, the ν ef picture is often valid, producing transport behavior differing from tokamaks

  8. Effect of mesoscopic fluctuations on equation of state in cluster-forming systems

    Directory of Open Access Journals (Sweden)

    A. Ciach

    2012-06-01

    Full Text Available Equation of state for systems with particles self-assembling into aggregates is derived within a mesoscopic theory combining density functional and field-theoretic approaches. We focus on the effect of mesoscopic fluctuations in the disordered phase. The pressure - volume fraction isotherms are calculated explicitly for two forms of the short-range attraction long-range repulsion potential. Mesoscopic fluctuations lead to an increased pressure in each case, except for very small volume fractions. When large clusters are formed, the mechanical instability of the system is present at much higher temperature than found in mean-field approximation. In this case phase separation competes with the formation of periodic phases (colloidal crystals. In the case of small clusters, no mechanical instability associated with separation into dilute and dense phases appears.

  9. The effects of observational correlated noises on multifractal detrended fluctuation analysis

    Science.gov (United States)

    Gulich, Damián; Zunino, Luciano

    2012-08-01

    We have numerically investigated the effects that observational correlated noises have on the generalized Hurst exponents, h(q), estimated by using the multifractal generalization of detrended fluctuation analysis (MF-DFA). More precisely, artificially generated stochastic binomial multifractals with increased amount of colored noises were analyzed via MF-DFA. It has been recently shown that for moderate additions of white noise, the generalized Hurst exponents are significantly underestimated for qeffects of additive noise, short- term memory and periodic trends, Physica A 390 (2011) 2480-2490]. In this paper, we have found that h(q) with q≥2 are also affected when correlated noises are considered. This is due to the fact that the spurious correlations influence the scaling behaviors associated to large fluctuations. The results obtained are significant for practical situations, where noises with different correlations are inherently present.

  10. Effect of pressure on spin fluctuations and superconductivity in heavy-fermion UPt3

    International Nuclear Information System (INIS)

    Willis, J.O.; Thompson, J.D.; Fisk, Z.; de Visser, A.; Franse, J.J.M.; Menovsky, A.

    1985-01-01

    We have determined the effect of hydrostatic pressure on the susceptibility, on the T 2 temperature dependence of the spin-fluctuation resistivity, and on superconductivity in UPt 3 . The spin-fluctuation temperature T/sub s/, derived from the slope of resistivity versus T 2 , is used within a Fermi-liquid picture to calculate the susceptibility chi at T = 0 K. The depression of this calculated chi with pressure agrees with the directly measured value partial lnchi/partialP = -24 Mbar -1 . Both the superconducting transition temperature T/sub c/ and the initial slope of the upper critical field also decrease under pressure. We find that partial lnT/sub c//partialP = -25 Mbar -1 and speculate upon correlations between chi and T/sub c/

  11. Effects of thermal fluctuations on non-minimal regular magnetic black hole

    International Nuclear Information System (INIS)

    Jawad, Abdul; Shahzad, M.U.

    2017-01-01

    We analyze the effects of thermal fluctuations on a regular black hole (RBH) of the non-minimal Einstein-Yang-Mill theory with gauge field of magnetic Wu-Yang type and a cosmological constant. We consider the logarithmic corrected entropy in order to analyze the thermal fluctuations corresponding to non-minimal RBH thermodynamics. In this scenario, we develop various important thermodynamical quantities, such as entropy, pressure, specific heats, Gibb's free energy and Helmholtz free energy. We investigate the first law of thermodynamics in the presence of logarithmic corrected entropy and non-minimal RBH. We also discuss the stability of this RBH using various frameworks such as the γ factor (the ratio of heat capacities), phase transition, grand canonical ensemble and canonical ensemble. It is observed that the non-minimal RBH becomes globally and locally more stable if we increase the value of the cosmological constant. (orig.)

  12. Effects of thermal fluctuations on non-minimal regular magnetic black hole

    Energy Technology Data Exchange (ETDEWEB)

    Jawad, Abdul [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); Shahzad, M.U. [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); University of Central Punjab, CAMS, UCP Business School, Lahore (Pakistan)

    2017-05-15

    We analyze the effects of thermal fluctuations on a regular black hole (RBH) of the non-minimal Einstein-Yang-Mill theory with gauge field of magnetic Wu-Yang type and a cosmological constant. We consider the logarithmic corrected entropy in order to analyze the thermal fluctuations corresponding to non-minimal RBH thermodynamics. In this scenario, we develop various important thermodynamical quantities, such as entropy, pressure, specific heats, Gibb's free energy and Helmholtz free energy. We investigate the first law of thermodynamics in the presence of logarithmic corrected entropy and non-minimal RBH. We also discuss the stability of this RBH using various frameworks such as the γ factor (the ratio of heat capacities), phase transition, grand canonical ensemble and canonical ensemble. It is observed that the non-minimal RBH becomes globally and locally more stable if we increase the value of the cosmological constant. (orig.)

  13. Temperature dependence of the upper critical field of type II superconductors with fluctuation effects

    International Nuclear Information System (INIS)

    Mikitik, G.P.

    1992-01-01

    Fluctuations of the order parameter are taken into consideration in an analysis of the temperature dependence of the upper critical field of a type II superconductor with a three-dimensional superconductivity. This temperature dependence is of universal applicability, to all type II superconductors, if the magnetic fields and temperatures are expressed in appropriate units. This dependence is derived explicitly for the regions of strong and weak magnetic fields. The results are applied to high T c superconductors, for which fluctuation effects are important. For these superconductors, the H c2 (T) dependence is quite different from the linear dependence characteristic of the mean-field theory, over a broad range of magnetic fields

  14. Fluctuations effects in diblock copolymer fluids: Comparison of theories and experiment

    International Nuclear Information System (INIS)

    Guenza, M.; Schweizer, K.S.

    1997-01-01

    The analytic Polymer Reference Interaction Site Model (PRISM) theory of structurally and interaction symmetric Gaussian diblock copolymer fluids is reformulated, extended, and applied to make predictions for experimentally observable equilibrium properties of the disordered state. These include the temperature, degree of polymerization, copolymer composition, and polymer density or concentration dependences of the peak scattering intensity, effective chi-parameter, and heat capacity. The location of the order-disorder transition is empirically estimated based on the disordered, strongly fluctuating state scattering function. Detailed numerical applications of PRISM theory demonstrates it provides an excellent description of the data. An in depth comparison of the mathematical structure and predictions of PRISM theory with the highly coarse-grained, incompressible Brazovski endash Leibler endash Fredrickson endash Helfand (BLFH) fluctuation corrected field theory is also carried out. Under some conditions (nearly symmetric composition, high melt densities, moderate temperatures) there are striking mathematical similarities between the predictions of the physically very different theories, although quantitative differences always persist. However, for strongly asymmetric copolymer compositions, short chains, compressible copolymer solutions, and low temperatures many qualitative differences emerge. The possibility of multiple, self-consistent fluctuation feedback mechanisms within the most general PRISM approach are identified, their qualitative features discussed, and contrasted with alternative versions of the fluctuation-corrected incompressible field theories due to BLFH and Stepanow. The predictions of PRISM and BLFH theory for the composition, copolymer density, temperature, and molecular weight dependence of the effective chi-parameter are presented and qualitatively compared with recent experiments. copyright 1997 American Institute of Physics

  15. Experimental and theoretical analyses of temperature polarization effect in vacuum membrane distillation

    KAUST Repository

    Alsaadi, Ahmad Salem; Francis, Lijo; Amy, Gary L.; Ghaffour, NorEddine

    2014-01-01

    This paper discusses the effect of temperature polarization in Vacuum Membrane Distillation (VMD). The main motivation for using VMD in this work is that this module configuration is much simpler and more suitable for this kind of investigation than the other MD configurations such as Direct Contact Membrane Distillation (DCMD). The coupling between heat and mass transfer mechanisms at the feed-membrane interface is presented from a theoretical point of view. In addition, a new simple graphical method and a mathematical model for determining VMD flux are presented. The two methods used in evaluating the extent of temperature polarization effect on water vapor flux (flux sensitivity factors and temperature polarization coefficient (TPC)) are also analyzed and compared. The effect of integrating a heat recovery system in a large scale module on the TPC coefficient has also been studied and presented in this paper. © 2014 Elsevier B.V.

  16. Experimental and theoretical analyses of temperature polarization effect in vacuum membrane distillation

    KAUST Repository

    Alsaadi, Ahmad Salem

    2014-08-13

    This paper discusses the effect of temperature polarization in Vacuum Membrane Distillation (VMD). The main motivation for using VMD in this work is that this module configuration is much simpler and more suitable for this kind of investigation than the other MD configurations such as Direct Contact Membrane Distillation (DCMD). The coupling between heat and mass transfer mechanisms at the feed-membrane interface is presented from a theoretical point of view. In addition, a new simple graphical method and a mathematical model for determining VMD flux are presented. The two methods used in evaluating the extent of temperature polarization effect on water vapor flux (flux sensitivity factors and temperature polarization coefficient (TPC)) are also analyzed and compared. The effect of integrating a heat recovery system in a large scale module on the TPC coefficient has also been studied and presented in this paper. © 2014 Elsevier B.V.

  17. Uses of the vacuum

    International Nuclear Information System (INIS)

    Rohrlich, D.M.

    1986-01-01

    Three problems in quantum field theory are analyzed. Each presents the vacuum in a different role. The connections among these significant roles are discussed in Chapter I. Chapter II contains a calculation of the zero-point energy in the Kaluza-Klein model. The zero-point fluctuations induce a potential which makes the compact dimensional contract. The effective potential is seen to be the four-dimensional version of the Casimir effect. Chapter III contains a Monte Carlo study of asymptotic freedom scales in lattice QCD. Two versions of SU(2) gauge theory, having different representations of the gauge group, are compared. A new method is used to calculate the ratio of scale parameters of the two theories. The method directly uses the weak-coupling behavior of the theories. The Monte-Carlo results are compared with perturbative calculations on the lattice, one of which is presented. They are in good agreement. Chapter IV applies the hypothesis of dimensional reduction to five-dimensional SU(2) and four-dimensional SO(3) lattice gauge theories. New analytic results for the strong- and weak-coupling limits are derived. Monte Carlo calculations show dimensional reduction in the strong coupling phases of both theories. At the phase transition, the two theories show a similar loss of dimensional reduction. An external source of random flux does not induce dimensional reduction where it is not already present

  18. Effects of vacuum rapid thermal annealing on the electrical characteristics of amorphous indium gallium zinc oxide thin films

    Directory of Open Access Journals (Sweden)

    Hyun-Woo Lee

    2018-01-01

    Full Text Available We investigated the effects of vacuum rapid thermal annealing (RTA on the electrical characteristics of amorphous indium gallium zinc oxide (a-IGZO thin films. The a-IGZO films deposited by radiofrequency sputtering were subjected to vacuum annealing under various temperature and pressure conditions with the RTA system. The carrier concentration was evaluated by Hall measurement; the electron concentration of the a-IGZO film increased and the resistivity decreased as the RTA temperature increased under vacuum conditions. In a-IGZO thin-film transistors (TFTs with a bottom-gate top-contact structure, the threshold voltage decreased and the leakage current increased as the vacuum RTA temperature increased. As the annealing pressure decreased, the threshold voltage decreased, and the leakage current increased. X-ray photoelectron spectroscopy indicated changes in the lattice oxygen and oxygen vacancies of the a-IGZO films after vacuum RTA. At higher annealing temperatures, the lattice oxygen decreased and oxygen vacancies increased, which suggests that oxygen was diffused out in a reduced pressure atmosphere. The formation of oxygen vacancies increased the electron concentration, which consequently increased the conductivity of the a-IGZO films and reduced the threshold voltage of the TFTs. The results showed that the oxygen vacancies and electron concentrations of the a-IGZO thin films changed with the vacuum RTA conditions and that high-temperature RTA treatment at low pressure converted the IGZO thin film to a conductor.

  19. Effects of vacuum rapid thermal annealing on the electrical characteristics of amorphous indium gallium zinc oxide thin films

    Science.gov (United States)

    Lee, Hyun-Woo; Cho, Won-Ju

    2018-01-01

    We investigated the effects of vacuum rapid thermal annealing (RTA) on the electrical characteristics of amorphous indium gallium zinc oxide (a-IGZO) thin films. The a-IGZO films deposited by radiofrequency sputtering were subjected to vacuum annealing under various temperature and pressure conditions with the RTA system. The carrier concentration was evaluated by Hall measurement; the electron concentration of the a-IGZO film increased and the resistivity decreased as the RTA temperature increased under vacuum conditions. In a-IGZO thin-film transistors (TFTs) with a bottom-gate top-contact structure, the threshold voltage decreased and the leakage current increased as the vacuum RTA temperature increased. As the annealing pressure decreased, the threshold voltage decreased, and the leakage current increased. X-ray photoelectron spectroscopy indicated changes in the lattice oxygen and oxygen vacancies of the a-IGZO films after vacuum RTA. At higher annealing temperatures, the lattice oxygen decreased and oxygen vacancies increased, which suggests that oxygen was diffused out in a reduced pressure atmosphere. The formation of oxygen vacancies increased the electron concentration, which consequently increased the conductivity of the a-IGZO films and reduced the threshold voltage of the TFTs. The results showed that the oxygen vacancies and electron concentrations of the a-IGZO thin films changed with the vacuum RTA conditions and that high-temperature RTA treatment at low pressure converted the IGZO thin film to a conductor.

  20. Effects of the amplitude and frequency of salinity fluctuations on antioxidant responses in juvenile tongue sole, Cynoglossus semilaevis

    Energy Technology Data Exchange (ETDEWEB)

    Khairnar, S.A.; Tian, X.; Dong, S.; Fang, Z.; Solanki, B.V.; Shanthanagouda, H.A.

    2016-11-01

    To understand the tolerance of tongue sole, Cynoglossus semilaevis, to varying salinities, the effects of the amplitude (2, 4, 6 and 8 g/L) and frequency (2, 4 and 8 days) of salinity fluctuations on the activities of antioxidant responses, including acidic phosphatase (ACP), alkaline phosphatase (AKP), catalase (CAT) and superoxide dismutase (SOD) from antioxidant system in liver, muscle, gills and kidney were investigated in this study. The results showed that the antioxidant responses of tongue sole were highly tissue-specific during the varying salinity fluctuations. In all tissues, ACP and AKP activity was found to be highest at moderate salinity fluctuations compared to the control, low and high salinity treatments (p<0.05). SOD and CAT activities had significant effect due to salinity fluctuations in all tissues (p<0.05), except in hepatic and renal tissues. Variations in branchial SOD activity proved that salinity fluctuations had greater impact on tongue sole at moderate and high fluctuating salinities compared to the control and low fluctuating salinities, whereas the branchial CAT activities showed contrasting trend. Further, cortisol levels were significantly affected in lower and higher salinity fluctuations. However, plasma cortisol levels remained low in moderate salinity fluctuations and control (p<0.05). Taken together, the results indicated that salinity fluctuations could effectively stimulate and enhance the antioxidant enzyme activity in the liver, kidney, gills and muscle of the juvenile tongue sole, thus effectively eliminating the excessive reactive oxygen species and minimizing the body damage in tongue sole or could be for any other euryhaline teleosts. (Author)

  1. Evaluation of synergistic effect in vacuum pack, refrigeration and irradiated treatments of minimally processed cassava

    International Nuclear Information System (INIS)

    Pedroso, Bianca Maria

    2005-01-01

    Cassava is cultivated almost all over the world and it is considered one of the most important nutritious sources of calories in the human diet. Cassava is a viable food against starvation in several poor areas of the world because it is an extremely resistant culture and may reach satisfactory economical yield. We utilized vacuum packed industrialized cassava irradiated with 0,1 kGy, 3kGy and 5kGy and stored under refrigeration for 1, 21, 30 and 50 days. Our objective was to analyse the synergistic effect of vacuum packing, irradiation and refrigeration on the preservation of minimally processed cassava. The samples were analyzed for pH, acidity, weight, humidity, texture and color. The irradiation did not affect the chemical characteristics of the cassava. Neither the pH nor the acidity, the most relevant variables to verify deterioration in cassava, presented significant alterations during the period of storage. Comparing the irradiated treatments, the dose of 1kGy and 3kGy affected the physic-chemical characteristics of the cassava the least during the period of storage and refrigeration for 50 days; the doses of 1kGy,3kGy and 5kGy scored the highest rates the sensorial analysis during the period of storage for 21 days. (author)

  2. Effect of Recycled Waste Polymers, Natural Bitumen and HVS Cut on the Properties of Vacuum Bottom

    Directory of Open Access Journals (Sweden)

    Y. Rasoulzadeh

    2013-01-01

    Full Text Available The neat bitumen, an oil refining by-product, has its own inherent weakness under long-time loading at low and high temperatures. These performance limitations of neat bitumen have led researchers to modify its physical andmechanical properties. According to several studies, polymers can be used to modify the properties of bitumen. Due to much lower production costs and aiming to reduce environmental impacts, recycled waste polymers are preferred as compared with virgin polymers. In this study, the effect of recycled waste polymers including crumb rubber modifier (CRM, polyethylene and latex and non-polymeric materials such as natural bitumen (NB and heavy vacuum slops (HVS cut on physical and mechanical properties of vacuum bottom residue (VB of crude oil distillation was investigat-ed. Based on the results, recycled waste polyethylene and NB can improve the performance grade of VB at high temperatures and CRM, latex and HVS can improve the performance grade of VB at low temperatures. Thus, by designing various blends of these additives with VB, different modified bitumens can be directly obtained from VB without any need to air-blowing process.

  3. Effect of vacuum and modified atmosphere packaging on microbiological properties of cold-smoked trout

    Science.gov (United States)

    Đorđević, J.; Pavlićević, N.; Bošković, M.; Janjić, J.; Glišić, M.; Starčević, M.; Baltić, M. Ž.

    2017-09-01

    Because of the importance of different packaging methods for the extension of fish shelf life, as a highly perishable food, the aim of the present study was to examine the effect of vacuum and modified atmosphere packaging on the total Enterobacteriaceae and lactic acid bacteria counts of cold-smoked Salmon trout (Oncorhynchus mykiss) stored at 3°C during six weeks. Trout fillets were vacuumed packaged (VP) or packaged in one of two different modified atmospheres, with gas ratio of 50%CO2/50%N2 (MAP1) and 90%CO2/10%N2 (MAP2) and analysed on days 0, 7, 14, 21, 28, 35 and 42. Both the total Enterobacteriaceae and total lactic acid bacteria counts increased in the trout fillets in all packaging types during storage. A significantly lower total Enterobacteriaceae count was determined in the MAP fish compared to the VP fish, with the weakest growth rate and lowest numbers attained in MAP2 fillets. The lactic acid bacteria count was higher in trout packaged in MAP compared to VP, with the highest number in the MAP with 90% CO2 (MAP2).

  4. Effect of vacuum annealing on evaporated pentacene thin films for memory device applications

    International Nuclear Information System (INIS)

    Gayathri, A.G.; Joseph, C.M.

    2016-01-01

    Graphical abstract: Switching of ITO/pentacene/Al thin films for different annealing temperatures. - Highlights: • Memory device performance in pentacene improved considerably with annealing. • ON/OFF ratio of the pentacene device increases due to annealing. • Threshold voltage reduces from 2.55 V to 1.35 V due to annealing. • Structure of pentacene thin films is also dependent on annealing temperature. - Abstract: Thin films of pentacene were deposited thermally onto glass substrates and annealed at 323 K, 373 K, 423 K, 473 K and 523 K in high vacuum. Effect of annealing on the morphological and structural properties of these films was studied. X-ray diffraction patterns confirmed the crystalline nature of the films. Electrical studies for the use as write once read many (WORM) memory devices were done for the vacuum deposited pentacene thin films on indium tin oxide coated glass. Due to annealing, a sharp increase in the ON/OFF ratio of current and a decrease in threshold voltage were observed at around 373 K. This device showed a stable switching with an ON/OFF current ratio as high as 10 9 and a switching threshold voltage of 1.35 V. The performance of the device degraded above 423 K due to the changes in the crystallinity of the film.

  5. Effect of vacuum annealing on evaporated pentacene thin films for memory device applications

    Energy Technology Data Exchange (ETDEWEB)

    Gayathri, A.G., E-mail: gaythri305@yahoo.com; Joseph, C.M., E-mail: cmjoseph@rediffmail.com

    2016-09-15

    Graphical abstract: Switching of ITO/pentacene/Al thin films for different annealing temperatures. - Highlights: • Memory device performance in pentacene improved considerably with annealing. • ON/OFF ratio of the pentacene device increases due to annealing. • Threshold voltage reduces from 2.55 V to 1.35 V due to annealing. • Structure of pentacene thin films is also dependent on annealing temperature. - Abstract: Thin films of pentacene were deposited thermally onto glass substrates and annealed at 323 K, 373 K, 423 K, 473 K and 523 K in high vacuum. Effect of annealing on the morphological and structural properties of these films was studied. X-ray diffraction patterns confirmed the crystalline nature of the films. Electrical studies for the use as write once read many (WORM) memory devices were done for the vacuum deposited pentacene thin films on indium tin oxide coated glass. Due to annealing, a sharp increase in the ON/OFF ratio of current and a decrease in threshold voltage were observed at around 373 K. This device showed a stable switching with an ON/OFF current ratio as high as 10{sup 9} and a switching threshold voltage of 1.35 V. The performance of the device degraded above 423 K due to the changes in the crystallinity of the film.

  6. Effectiveness of vacuum-assisted closure (VAC) therapy in the healing of chronic diabetic foot ulcers.

    Science.gov (United States)

    Nather, Aziz; Chionh, Siok Bee; Han, Audrey Y Y; Chan, Pauline P L; Nambiar, Ajay

    2010-05-01

    This is the fi rst prospective study done locally to determine the effectiveness of vacuum-assisted closure (VAC) therapy in the healing of chronic diabetic foot ulcers. An electronic vacuum pump was used to apply controlled negative pressure evenly across the wound surface. Changes in wound dimension, presence of wound granulation and infection status of diabetic foot ulcers in 11 consecutive patients with diabetes were followed over the course of VAC therapy. Healing was achieved in all wounds. Nine wounds were closed by split-skin grafting and 2 by secondary closure. The average length of treatment with VAC therapy was 23.3 days. Ten wounds showed reduction in wound size. All wounds were satisfactorily granulated and cleared of bacterial infection at the end of VAC therapy. VAC therapy was useful in the treatment of diabetic foot infection and ulcers, which after debridement, may present with exposed tendon, fascia and/or bone. These included ray amputation wounds, wounds post-debridement for necrotising fasciitis, wounds post-drainage for abscess, a heel ulcer and a sole ulcer. It was able to prepare ulcers well for closure via split-skin grafting or secondary closure in good time. This reduced cost of VAC therapy, as therapy was not prolonged to attain greater reduction in wound area. VAC therapy also provides a sterile, more controlled resting environment to large, exudating wound surfaces. Large diabetic foot ulcers were thus made more manageable.

  7. Effect of river flow fluctuations on riparian vegetation dynamics: Processes and models

    Science.gov (United States)

    Vesipa, Riccardo; Camporeale, Carlo; Ridolfi, Luca

    2017-12-01

    Several decades of field observations, laboratory experiments and mathematical modelings have demonstrated that the riparian environment is a disturbance-driven ecosystem, and that the main source of disturbance is river flow fluctuations. The focus of the present work has been on the key role that flow fluctuations play in determining the abundance, zonation and species composition of patches of riparian vegetation. To this aim, the scientific literature on the subject, over the last 20 years, has been reviewed. First, the most relevant ecological, morphological and chemical mechanisms induced by river flow fluctuations are described from a process-based perspective. The role of flow variability is discussed for the processes that affect the recruitment of vegetation, the vegetation during its adult life, and the morphological and nutrient dynamics occurring in the riparian habitat. Particular emphasis has been given to studies that were aimed at quantifying the effect of these processes on vegetation, and at linking them to the statistical characteristics of the river hydrology. Second, the advances made, from a modeling point of view, have been considered and discussed. The main models that have been developed to describe the dynamics of riparian vegetation have been presented. Different modeling approaches have been compared, and the corresponding advantages and drawbacks have been pointed out. Finally, attention has been paid to identifying the processes considered by the models, and these processes have been compared with those that have actually been observed or measured in field/laboratory studies.

  8. Effect of thermal fluctuations in spin-torque driven magnetization dynamics

    International Nuclear Information System (INIS)

    Bonin, R.; Bertotti, G.; Serpico, C.; Mayergoyz, I.D.; D'Aquino, M.

    2007-01-01

    Nanomagnets with uniaxial symmetry driven by an external field and spin-polarized currents are considered. Anisotropy, applied field, and spin polarization are all aligned along the symmetry axis. Thermal fluctuations are described by adding a Gaussian white noise stochastic term to the Landau-Lifshitz-Gilbert equation for the deterministic dynamics. The corresponding Fokker-Planck equation is derived. It is shown that deterministic dynamics, thermal relaxation, and transition rate between stable states are governed by an effective potential including the effect of current injection

  9. Effect of thermal fluctuations in spin-torque driven magnetization dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bonin, R. [INRiM, I-10135 Turin (Italy)]. E-mail: bonin@inrim.it; Bertotti, G. [INRiM, I-10135 Turin (Italy); Serpico, C. [Dipartimento di Ingegneria Elettrica, Universita di Napoli ' Federico II' I-80125 Naples (Italy); Mayergoyz, I.D. [Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742 (United States); D' Aquino, M. [Dipartimento per le Tecnologie, Universita di Napoli ' Parthenope' , I-80133 Naples (Italy)

    2007-09-15

    Nanomagnets with uniaxial symmetry driven by an external field and spin-polarized currents are considered. Anisotropy, applied field, and spin polarization are all aligned along the symmetry axis. Thermal fluctuations are described by adding a Gaussian white noise stochastic term to the Landau-Lifshitz-Gilbert equation for the deterministic dynamics. The corresponding Fokker-Planck equation is derived. It is shown that deterministic dynamics, thermal relaxation, and transition rate between stable states are governed by an effective potential including the effect of current injection.

  10. Effects of environmental temperature fluctuations on the parameters of a thermoelectric battery

    International Nuclear Information System (INIS)

    Kozlov, Yu.F.; Oganov, E.P.

    1980-01-01

    A numerical analysis is presented for the effects of lags on the output parameters of a radioisotope thermoelectric battery under conditions of diurnal temperature variation in the environment. Allowance for the inertial effects causes a phase shift and change in amplitude of the variations in the thermal and electrical parameters. The amplitude of the temperature fluctuations in the hot junctions is substantially reduced, while the output electrical power increases. The data provide a more rigorous basis for choosing the parameters of radioisotope batteries during design. 9 refs

  11. Kovacs effect and fluctuation-dissipation relations in 1D kinetically constrained models

    International Nuclear Information System (INIS)

    Buhot, Arnaud

    2003-01-01

    Strong and fragile glass relaxation behaviours are obtained simply changing the constraints of the kinetically constrained Ising chain from symmetric to purely asymmetric. We study the out-of-equilibrium dynamics of these two models focusing on the Kovacs effect and the fluctuation-dissipation (FD) relations. The Kovacs or memory effect, commonly observed in structural glasses, is present for both constraints but enhanced with the asymmetric ones. Most surprisingly, the related FD relations satisfy the FD theorem in both cases. This result strongly differs from the simple quenching procedure where the asymmetric model presents strong deviations from the FD theorem

  12. Effects of Demographic Noise on the Synchronization of a Metapopulation in a Fluctuating Environment

    KAUST Repository

    Lai, Yi Ming

    2011-09-08

    We use the theory of noise-induced phase synchronization to analyze the effects of demographic noise on the synchronization of a metapopulation of predator-prey systems within a fluctuating environment (Moran effect). Treating each local predator-prey population as a stochastic urn model, we derive a Langevin equation for the stochastic dynamics of the metapopulation. Assuming each local population acts as a limit cycle oscillator in the deterministic limit, we use phase reduction and averaging methods to derive the steady-state probability density for pairwise phase differences between oscillators, which is then used to determine the degree of synchronization of the metapopulation. © 2011 American Physical Society.

  13. Vacuum tension effects on the evolution of domain walls in the early universe

    International Nuclear Information System (INIS)

    Aurilia, A.

    1984-06-01

    The ''vacuum pressure'' mechanism of the hadronic bag model is taken as a guide to formulate the dynamics of closed domain walls in the cosmological case. The effective action functional suggested by this analogy is a straightforward generalization of the Einstein-Maxwell action: it involves a 3-index antisymmetric potential whose coupling to matter generates two effective cosmological constants, one inside and one outside the domain wall. It is suggested that this mechanism, which is alternative to the introduction of a Higgs potential, is the source of the bubble nucleation process envisaged in the New Inflationary Cosmology. The dynamics of a spherical domain in a de Sitter phase is analyzed and is consistent with the geometrical formulation of shell dynamics proposed long ago by Israel. (author)

  14. Rectification effect about vacuum separating carbon nanotube bundle predicted by first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Min, Y., E-mail: minshiyi@gmail.com [School of Science, Nantong University, Nantong, Jiangsu, 226007 (China); Fang, J.H.; Zhong, C.G. [School of Science, Nantong University, Nantong, Jiangsu, 226007 (China); Yao, K.L. [School of Physics, Huazhong University of Science and Technology, Wuhan, 430074 (China)

    2012-05-07

    For the molecular spintronics transport systems, we propose that the spin current rectifier can be constructed using the nonmagnetic lead. The proposal is confirmed according to the first-principles study of the transport characteristics of a vacuum separating (15,0) carbon nanotube bundle where only one zigzag edge is hydrogenated. The strong rectification effect for spin (charge) current is obtained in the case of the magnetic parallel (anti-parallel) configuration of two zigzag edges. Our investigations indicate that such device can be used as the spin filter and the counterpart of the p–n junction in the field of molecular electronics. -- Highlights: ► We propose that nonmagnetic leads can construct spin current rectifier. ► We propose a spin diode and a filter using CNT. ► The spin and charge current all have the rectification effect in the one-dimensional spin diode.

  15. Vacuum extraction

    DEFF Research Database (Denmark)

    Maagaard, Mathilde; Oestergaard, Jeanett; Johansen, Marianne

    2012-01-01

    Objectives. To develop and validate an Objective Structured Assessment of Technical Skills (OSATS) scale for vacuum extraction. Design. Two-part study design: Primarily, development of a procedure-specific checklist for vacuum extraction. Hereafter, validation of the developed OSATS scale for vac...

  16. Vacuum mechatronics

    Science.gov (United States)

    Hackwood, Susan; Belinski, Steven E.; Beni, Gerardo

    1989-01-01

    The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an increased application of vacuum in space studies and in manufacturing for material processing, medicine, microelectronics, emission studies, lyophylisation, freeze drying and packaging. The quickly developing field of vacuum mechatronics will also be the driving force for the realization of an advanced era of totally enclosed clean manufacturing cells. High technology manufacturing has increasingly demanding requirements for precision manipulation, in situ process monitoring and contamination-free environments. To remove the contamination problems associated with human workers, the tendency in many manufacturing processes is to move towards total automation. This will become a requirement in the near future for e.g., microelectronics manufacturing. Automation in ultra-clean manufacturing environments is evolving into the concept of self-contained and fully enclosed manufacturing. A Self Contained Automated Robotic Factory (SCARF) is being developed as a flexible research facility for totally enclosed manufacturing. The construction and successful operation of a SCARF will provide a novel, flexible, self-contained, clean, vacuum manufacturing environment. SCARF also requires very high reliability and intelligent control. The trends in vacuum mechatronics and some of the key research issues are reviewed.

  17. Temporal and spatial variations in wildlife population fluctuations in Greenland; The effect of climate, environment and man

    DEFF Research Database (Denmark)

    Moshøj, Charlotte Margaret; Forchhammer, Mads C.; Forbes, Valery E.

    2009-01-01

    Temporal and spatial variations in wildlife population fluctuations in Greenland; The effect of climate, environment and man Moshøj, C.M, M.C.Forchhammer and V.E. Forbes Temporal and spatial variations in wildlife population fluctuations in Greenland; The effect of climate, environment and man...... and mammals display distinct population fluctuations of varying temporal and spatial scale. In Greenland, historical records, archaeological findings and oral accounts passed on from Inuit elders all document that the presence of wildlife species and their population sizes have undergone pronounced....... The results of this study will model future predictions of wildlife populations under changing climate variables and human hunting pressure....

  18. Impacts of friction stir processing on irradiation effects in vacuum-plasma-spray coated tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Ozawa, Kazumi, E-mail: ozawa.kazumi@jaea.go.jp [Fusion Research and Development Directorate, Japan Atomic Energy Agency, 2-166 Obuchi-Omotedate, Rokkasho, Aomori 039-3212 (Japan); Tanigawa, Hiroyasu [Fusion Research and Development Directorate, Japan Atomic Energy Agency, 2-166 Obuchi-Omotedate, Rokkasho, Aomori 039-3212 (Japan); Morisada, Yoshiaki; Fujii, Hidetoshi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2015-10-15

    In order to examine the impacts of friction stir processing (FSP) on irradiation effects in vacuum-plasma-spray (VPS) coated tungsten (W), nano indentation hardness was evaluated of three kinds of W materials after self-ion-irradiation to 5.0–5.4 dpa at 500 and 800 °C. The VPS-FSP clearly got grains refined and isotropic compared to bulk-W and the as-VPS-W. Nano indentation hardness remains unchanged for the as-VPS-W and VPS-FSP × 2-W irradiated to 5.4 dpa at 500 °C and it decreased from 1 dpa at 800 °C, while typical irradiation induced hardening was observed for the bulk-W irradiated at 500 °C.

  19. Quantum Prisoners' Dilemma in Fluctuating Massless Scalar Field

    Science.gov (United States)

    Huang, Zhiming

    2017-12-01

    Quantum systems are easily affected by external environment. In this paper, we investigate the influences of external massless scalar field to quantum Prisoners' Dilemma (QPD) game. We firstly derive the master equation that describes the system evolution with initial maximally entangled state. Then, we discuss the effects of a fluctuating massless scalar field on the game's properties such as payoff, Nash equilibrium, and symmetry. We find that for different game strategies, vacuum fluctuation has different effects on payoff. Nash equilibrium is broken but the symmetry of the game is not violated.

  20. Pairing fluctuation effects on the single-particle spectra for the superconducting state

    International Nuclear Information System (INIS)

    Pieri, P.; Pisani, L.; Strinati, G.C.

    2004-01-01

    Single-particle spectra are calculated in the superconducting state for a fermionic system with an attractive interaction, as functions of temperature and coupling strength from weak to strong. The fermionic system is described by a single-particle self-energy that includes pairing-fluctuation effects in the superconducting state. The theory reduces to the ordinary BCS approximation in weak coupling and to the Bogoliubov approximation for the composite bosons in strong coupling. Several features of the single-particle spectral function are shown to compare favorably with experimental data for cuprate superconductors

  1. Effect of particle velocity fluctuations on the inertia coupling in two-phase flow

    International Nuclear Information System (INIS)

    Drew, D.A.

    1989-01-01

    Consistent forms for the interfacial force, the interfacial pressure, the Reynolds stresses and the particle stress have been derived for the inviscid, irrotational incompressible flow of fluid in a dilute suspension of spheres. The particles are assumed to have a velocity distribution, giving rise to an effective pressure and stress in the particle phase. The velocity fluctuations also contribute in the fluid Reynolds stress and in the (elastic) stress field inside the spheres. The relation of these constitutive equations to the force on an individual sphere is discussed

  2. Fluctuation effects in first-order phase transitions: Theory and model for martensitic transformations

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker; Mouritsen, Ole G.

    1990-01-01

    We discuss central questions in weak, first-order structural transitions by means of a magnetic analog model. A theory including fluctuation effects is developed for the model, showing a dynamical response with softening, fading modes and a growing central peak. The model is also analyzed by a two......-dimensional Monte Carlo simulation, showing clear precursor phenomena near the first-order transition and spontaneous nucleation. The kinetics of the domain growth is studied and found to be exceedingly slow. The results are applicable for martensitic transformations and structural surface...

  3. Fluctuation and dipolar interaction effects on the pinning of domain walls

    International Nuclear Information System (INIS)

    Chui, S.T.

    2001-01-01

    We discuss the effect of the dipolar interaction on the pinning of domain walls. Domain walls are usually pinned near the boundaries between grains. Magnetic charges accumulated at the domain wall make the wall more unstable and easier to depin. We discuss how the grain-orientation and thermal fluctuations affect these magnetic charges and hence the depinning of the domain walls. Our results are illustrated by finite temperature Monte Carlo simulation on periodic arrays of large cells separated by walls consisting of faces of pyramids

  4. Effect of vacuum energy on evolution of primordial black holes in Einstein gravity

    International Nuclear Information System (INIS)

    Nayak, Bibekananda; Jamil, Mubasher

    2012-01-01

    We study the evolution of primordial black holes by considering present universe is no more matter dominated rather vacuum energy dominated. We also consider the accretion of radiation, matter and vacuum energy during respective dominance period. In this scenario, we found that radiation accretion efficiency should be less than 0.366 and accretion rate is much larger than previous analysis by Nayak et al. (2009) . Thus here primordial black holes live longer than previous works Nayak and Singh (2011). Again matter accretion slightly increases the mass and lifetime of primordial black holes. However, the vacuum energy accretion is slightly complicated one, where accretion is possible only up to a critical time. If a primordial black hole lives beyond critical time, then its' lifespan increases due to vacuum energy accretion. But for presently evaporating primordial black holes, critical time comes much later than their evaporating time and thus vacuum energy could not affect those primordial black holes.

  5. Synchrotron Vacuum Ultraviolet Light and Soft X-Ray Radiation Effects on Aluminized Teflon FEP Investigated

    Science.gov (United States)

    Dever, Joyce A.; Townsend, Jacqueline A.; Gaier, James R.; Jalics, Alice I.

    1999-01-01

    Since the Hubble Space Telescope (HST) was deployed in low Earth orbit in April 1990, two servicing missions have been conducted to upgrade its scientific capabilities. Minor cracking of second-surface metalized Teflon FEP (DuPont; fluorinated ethylene propylene) surfaces from multilayer insulation (MLI) was first observed upon close examination of samples with high solar exposure retrieved during the first servicing mission, which was conducted 3.6 years after deployment. During the second HST servicing mission, 6.8 years after deployment, astronaut observations and photographic documentation revealed significant cracks in the Teflon FEP layer of the MLI on both the solar- and anti-solar-facing surfaces of the telescope. NASA Goddard Space Flight Center directed the efforts of the Hubble Space Telescope MLI Failure Review Board, whose goals included identifying the low-Earth-orbit environmental constituent(s) responsible for the cracking and embrittling of Teflon FEP which was observed during the second servicing mission. The NASA Lewis Research Center provided significant support to this effort. Because soft x-ray radiation from solar flares had been considered as a possible cause for the degradation of the mechanical properties of Teflon FEP (ref. 1), the effects of soft xray radiation and vacuum ultraviolet light on Teflon FEP were investigated. In this Lewisled effort, samples of Teflon FEP with a 100-nm layer of vapor-deposited aluminum (VDA) on the backside were exposed to synchrotron radiation of various vacuum ultraviolet and soft x-ray wavelengths between 18 nm (69 eV) and 0.65 nm (1900 eV). Synchrotron radiation exposures were conducted using the National Synchrotron Light Source at Brookhaven National Laboratory. Samples of FEP/VDA were exposed with the FEP surface facing the synchrotron beam. Doses and fluences were compared with those estimated for the 20-yr Hubble Space Telescope mission.

  6. Manual vacuum aspirator: a safe and effective tool for decentralization of post miscarriage care

    International Nuclear Information System (INIS)

    Tasnim, N.; Fatima, S.; Mahmud, G.

    2014-01-01

    Objective: To compare the efficacy and safety of Manual Vacuum Aspiration (MVA) performed as outpatient versus inpatient procedure in terms of success rate, blood loss, hospital stay and procedure related complications. Study Design: A quasi-experimental study. Place and Duration of Study: Maternal and Child Health Centre (MCHC), Unit-I, Pakistan Institute of Medical Sciences (PIMS), Islamabad, from December 2009 to December 2010. Methodology: Cases with early pregnancy failure (incomplete, missed and an embryonic) at gestational age less than 12 weeks were allocated to MVA as outpatient or elective procedure performed in the operation theatre. Studied variables were noted as above. Results: A total of 177 women were eligible for study, out of whom 78 underwent MVA as outpatient procedure and 99 as indoor procedure. The baseline characteristics were comparable in both groups except significantly high multipara in the indoor group. Complete evacuation was achieved in 96.1% in outpatient vs. 79.7% in indoor cases (p=0.001). Outpatient group had a shorter hospital stay (median 3 hours, IQR-1 vs. 10 hours, IQR-4; p = 0.001), though the median hospital cost was less but statistically insignificant (Rs. 800, IQR-25 vs. 735, IQR-1265; p=0.728). Blood loss was comparable in both groups (median 60 ml, IQR-20 vs. 60 ml-IQR-30; p=0.350). There were two uterine perforations noted in the inpatient group (2.02%) vs. none in outpatient setting. Conclusion: Outpatient based manual vacuum aspiration is a safe and effective tool for management of early pregnancy loss. A decentralized approach proved useful in reducing hospital stay. (author)

  7. Deformation and concentration fluctuations under stretching in a polymer network with free chains. The ''butterfly'' effect

    International Nuclear Information System (INIS)

    Ramzi, A.

    1994-06-01

    Small Angle Neutron Scattering gives access to concentration fluctuations of mobile labeled polymer chains embedded in a polymer network. At rest they appear progressively larger than for random mixing, with increasing ratio. Under uniaxial stretching, they decrease towards ideal mixing along the direction perpendicular to stretching, and can grow strongly along the parallel one, including the zero scattering vector q limit. This gives rise to intensity contours with double-winged patterns, in the shape of the figure '8', or of 'butterfly'. Random crosslinking and end-linking of monodisperse chains have both been studied. The strength of the 'butterfly' effect increases with the molecular weight of the free chains, the crosslinking ratio, the network heterogeneity, and the elongation ratio. Eventually, the signal collapses on an 'asymptotic' function I(q), of increasing correlation length with the elongation ratio. Deformation appears heterogeneous, maximal for soft areas, where the mobile chains localize preferentially. This could be due to spontaneous fluctuations, or linked to frozen fluctuations of the crosslink density. However, disagreement with the corresponding theoretical expressions makes it necessary to account for the spatial correlations of crosslink density, and their progressive unscreening as displayed by the asymptotic behavior. Networks containing pending labeled chains and free labeled stars lead to more precise understanding of the diffusion of free species and the heterogeneity of the deformation. It seems that the latter occurs even without diffusion for heterogeneous enough networks. In extreme cases (of the crosslinking parameters), the spatial correlations display on apparent fractal behavior, of dimensions 2 to 2.5, which is discussed here in terms of random clusters. 200 refs., 95 figs., 21 tabs., 10 appends

  8. Effects of dietary magnesium and duration of refrigerated storage on the quality of vacuum-packaged, boneless pork loins.

    Science.gov (United States)

    Apple, J K; Davis, J R; Rakes, L K; Maxwell, C V; Stivarius, M R; Pohlman, F W

    2001-01-01

    Quality data were initially collected on 78 pork loins from crossbred pigs fed diets containing 0, 1.25 or 2.5% magnesium mica (MM). Loins were then vacuum-packaged, and randomly assigned to either 4 or 8 weeks of storage at 2°C. Dietary MM had no (P > 0.05) effect on moisture loss/retention or subjective and objective color measurements. Purge volume increased (Pwater-holding capacity of pork loins during storage, the data indicated inclusion of MM in swine diets may retard onset of oxidative rancidity in vacuum-packaged pork loins.

  9. Cosmic vacuum

    International Nuclear Information System (INIS)

    Chernin, Artur D

    2001-01-01

    Recent observational studies of distant supernovae have suggested the existence of cosmic vacuum whose energy density exceeds the total density of all the other energy components in the Universe. The vacuum produces the field of antigravity that causes the cosmological expansion to accelerate. It is this accelerated expansion that has been discovered in the observations. The discovery of cosmic vacuum radically changes our current understanding of the present state of the Universe. It also poses new challenges to both cosmology and fundamental physics. Why is the density of vacuum what it is? Why do the densities of the cosmic energy components differ in exact value but agree in order of magnitude? On the other hand, the discovery made at large cosmological distances of hundreds and thousands Mpc provides new insights into the dynamics of the nearby Universe, the motions of galaxies in the local volume of 10 - 20 Mpc where the cosmological expansion was originally discovered. (reviews of topical problems)

  10. Cosmic vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Chernin, Artur D [P.K. Shternberg State Astronomical Institute at the M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2001-11-30

    Recent observational studies of distant supernovae have suggested the existence of cosmic vacuum whose energy density exceeds the total density of all the other energy components in the Universe. The vacuum produces the field of antigravity that causes the cosmological expansion to accelerate. It is this accelerated expansion that has been discovered in the observations. The discovery of cosmic vacuum radically changes our current understanding of the present state of the Universe. It also poses new challenges to both cosmology and fundamental physics. Why is the density of vacuum what it is? Why do the densities of the cosmic energy components differ in exact value but agree in order of magnitude? On the other hand, the discovery made at large cosmological distances of hundreds and thousands Mpc provides new insights into the dynamics of the nearby Universe, the motions of galaxies in the local volume of 10 - 20 Mpc where the cosmological expansion was originally discovered. (reviews of topical problems)

  11. Ultra high vacuum technology

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    A short introduction for some basic facts and equations. Subsquently, discussion about: Building blocks of an ultrahigh vacuum system - Various types of pumps required to reach uhv and methods to reduce these effects - Outgassing phenomena induced by the presence of a particle beam and the most common methods to reduce these effects It will be given some practical examples from existing CERN accelerators and discuss the novel features of the future LHC vacuum system.

  12. Effects of plasma and vacuum-ultraviolet exposure on the mechanical properties of low-k porous organosilicate glass

    Science.gov (United States)

    X. Guo; J.E. Jakes; S. Banna; Y. Nishi; J.L. Shohet

    2014-01-01

    The effects of plasma exposure and vacuum-ultraviolet (VUV) irradiation on the mechanical properties of low-k porous organosilicate glass (SiCOH) dielectric films were investigated. Nanoindentation measurements were made on SiCOH films before and after exposure to an electron-cyclotron-resonance plasma or a monochromatic synchrotron VUV beam, to determine the changes...

  13. Effect of the ground state correlations in the density distribution and zero point fluctuations

    International Nuclear Information System (INIS)

    Barranco, F.; Broglia, R.A.

    1985-01-01

    The existence of collective vibrations in the spectrum implies that the description of the ground state in an independent particle model must be corrected. This is because of the zero point fluctuations induced by the collective vibrations, so that ground state correlations have to be included. These are taken into account via the diagrammatic expansion of the Nuclear Field Theory, giving place to a renormalization in the different properties of the ground state. As far as the density distribution is concerned, in a NFT consistent calculation, the largest contributions arise from diagrams that cannot be expressed in terms of backward going amplitudes of the phonon RPA wave function. For a given multipolarity the main correction comes from the low lying state. The giant resonance is of smaller relevance since it lies at larger energies in the response function. The octupole modes give the dominant contribution, and the effect in average becomes smaller as the multipolarity increases. These results agree quite well with those obtained taking into account the zero point fluctuations of the nuclear surface in the collective model with the Esbensen and Bertsch prescription, which the authors use to explain the anomalous behaviour of the mean square radii of the Calcium isotopes

  14. Load variation effects on the pressure fluctuations exerted on a Kaplan turbine runner

    International Nuclear Information System (INIS)

    Amiri, K; Cervantes, M J; Mulu, B; Raisee, M

    2014-01-01

    Introduction of intermittent electricity production systems like wind power and solar systems to electricity market together with the consumption-based electricity production resulted in numerous start/stops, load variations and off-design operation of water turbines. The hydropower systems suffer from the varying loads exerted on the stationary and rotating parts of the turbines during load variations which they are not designed for. On the other hand, investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of rotating vortex rope (RVR) in the draft tube. The RVR induces oscillating flow both in plunging and rotating modes which results in oscillating force with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. The purpose of this study is to investigate the effect of transient operations on the pressure fluctuations on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors. The model was run in off-cam mode during different load variation conditions to check the runner performance under unsteady condition. The results showed that the transients between the best efficiency point and the high load happens in a smooth way while transitions to/from the part load, where rotating vortex rope (RVR) forms in the draft tube induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode of the RVR

  15. Load variation effects on the pressure fluctuations exerted on a Kaplan turbine runner

    Science.gov (United States)

    Amiri, K.; Mulu, B.; Raisee, M.; Cervantes, M. J.

    2014-03-01

    Introduction of intermittent electricity production systems like wind power and solar systems to electricity market together with the consumption-based electricity production resulted in numerous start/stops, load variations and off-design operation of water turbines. The hydropower systems suffer from the varying loads exerted on the stationary and rotating parts of the turbines during load variations which they are not designed for. On the other hand, investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of rotating vortex rope (RVR) in the draft tube. The RVR induces oscillating flow both in plunging and rotating modes which results in oscillating force with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. The purpose of this study is to investigate the effect of transient operations on the pressure fluctuations on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors. The model was run in off-cam mode during different load variation conditions to check the runner performance under unsteady condition. The results showed that the transients between the best efficiency point and the high load happens in a smooth way while transitions to/from the part load, where rotating vortex rope (RVR) forms in the draft tube induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode of the RVR.

  16. Antibody fluctuations of infected cattle with Fasciola gigantica and the effect of triclabendazole treatment

    Directory of Open Access Journals (Sweden)

    S Widjajanti

    2001-12-01

    Full Text Available Observation on the antibody fluctuations of infected cattle with metacercariae of Fasciola gigantica and the effect of triclabendazole treatment were made by means of ELISA technique. Seven cattle were infected with 700 metacercariae and one cattle remained uninfected, as negative control animal. Treatment with triclabendazole was given to 6 cattle, when the mean antibody levels of infected cattle reached the peak, and the other one remained untreated, as positive control animal. One week after treatment the mean antibody levels started to drop and then decreased gradually. After eight weeks of treatment, the mean antibody levels of the treated cattle reached the lowest level or the same value as before infection, thereafter, 6 cattle were reinfected with different dosages of metacercariae of F. gigantica. Two cattle were infected with 400 metacercariae, the other two were infected with 600 metacercariae and the rest of them were infected with 800 metacercariae. The results showed that the immunological responses of re-infected cattle are quicker (5 weeks after infection and the peak of the antibody levels are higher (ELISA OD = 1.7 than after the first infection (11 weeks after infection and ELISA OD = 1.2. However, after re-infection, there were no significant different on the antibody fluctuations and antibody levels among the infected group, although those cattle received different dosages.

  17. Algorithmic modeling of the irrelevant sound effect (ISE) by the hearing sensation fluctuation strength.

    Science.gov (United States)

    Schlittmeier, Sabine J; Weissgerber, Tobias; Kerber, Stefan; Fastl, Hugo; Hellbrück, Jürgen

    2012-01-01

    Background sounds, such as narration, music with prominent staccato passages, and office noise impair verbal short-term memory even when these sounds are irrelevant. This irrelevant sound effect (ISE) is evoked by so-called changing-state sounds that are characterized by a distinct temporal structure with varying successive auditory-perceptive tokens. However, because of the absence of an appropriate psychoacoustically based instrumental measure, the disturbing impact of a given speech or nonspeech sound could not be predicted until now, but necessitated behavioral testing. Our database for parametric modeling of the ISE included approximately 40 background sounds (e.g., speech, music, tone sequences, office noise, traffic noise) and corresponding performance data that was collected from 70 behavioral measurements of verbal short-term memory. The hearing sensation fluctuation strength was chosen to model the ISE and describes the percept of fluctuations when listening to slowly modulated sounds (f(mod) background sounds, the algorithm estimated behavioral performance data in 63 of 70 cases within the interquartile ranges. In particular, all real-world sounds were modeled adequately, whereas the algorithm overestimated the (non-)disturbance impact of synthetic steady-state sounds that were constituted by a repeated vowel or tone. Implications of the algorithm's strengths and prediction errors are discussed.

  18. Mechano-genetic DNA hydrogels as a simple, reconstituted model to probe the effect of active fluctuations on gene transcription

    Science.gov (United States)

    Nguyen, Dan; Saleh, Omar

    Active fluctuations - non-directed fluctuations attributable, not to thermal energy, but to non-equilibrium processes - are thought to influence biology by increasing the diffusive motion of biomolecules. Dense DNA regions within cells (i.e. chromatin) are expected to exhibit such phenomena, as they are cross-linked networks that continually experience propagating forces arising from dynamic cellular activity. Additional agitation within these gene-encoding DNA networks could have potential genetic consequences. By changing the local mobility of transcriptional machinery and regulatory proteins towards/from their binding sites, and thereby influencing transcription rates, active fluctuations could prove to be a physical means of modulating gene expression. To begin probing this effect, we construct genetic DNA hydrogels, as a simple, reconstituted model of chromatin, and quantify transcriptional output from these hydrogels in the presence/absence of active fluctuations.

  19. The effect of interaural-level-difference fluctuations on the externalization of sound

    DEFF Research Database (Denmark)

    Catic, Jasmina; Santurette, Sébastien; Buchholz, Jörg M.

    2013-01-01

    Real-world sound sources are usually perceived as externalized and thus properly localized in both direction and distance. This is largely due to (1) the acoustic filtering by the head, torso, and pinna, resulting in modifications of the signal spectrum and thereby a frequency-dependent shaping...... of interaural cues and (2) interaural cues provided by the reverberation inside an enclosed space. This study first investigated the effect of room reverberation on the spectro-temporal behavior of interaural level differences (ILDs) by analyzing dummy-head recordings of speech played at different distances...... in a standard listening room. Next, the effect of ILD fluctuations on the degree of externalization was investigated in a psychoacoustic experiment performed in the same listening room. Individual binaural impulse responses were used to simulate a distant sound source delivered via headphones. The ILDs were...

  20. Faraday-effect polarimeter diagnostic for internal magnetic field fluctuation measurements in DIII-D.

    Science.gov (United States)

    Chen, J; Ding, W X; Brower, D L; Finkenthal, D; Muscatello, C; Taussig, D; Boivin, R

    2016-11-01

    Motivated by the need to measure fast equilibrium temporal dynamics, non-axisymmetric structures, and core magnetic fluctuations (coherent and broadband), a three-chord Faraday-effect polarimeter-interferometer system with fast time response and high phase resolution has recently been installed on the DIII-D tokamak. A novel detection scheme utilizing two probe beams and two detectors for each chord results in reduced phase noise and increased time response [δb ∼ 1G with up to 3 MHz bandwidth]. First measurement results were obtained during the recent DIII-D experimental campaign. Simultaneous Faraday and density measurements have been successfully demonstrated and high-frequency, up to 100 kHz, Faraday-effect perturbations have been observed. Preliminary comparisons with EFIT are used to validate diagnostic performance. Principle of the diagnostic and first experimental results is presented.

  1. Faraday-effect polarimeter diagnostic for internal magnetic field fluctuation measurements in DIII-D

    International Nuclear Information System (INIS)

    Chen, J.; Ding, W. X.; Brower, D. L.; Finkenthal, D.; Muscatello, C.; Taussig, D.; Boivin, R.

    2016-01-01

    Motivated by the need to measure fast equilibrium temporal dynamics, non-axisymmetric structures, and core magnetic fluctuations (coherent and broadband), a three-chord Faraday-effect polarimeter-interferometer system with fast time response and high phase resolution has recently been installed on the DIII-D tokamak. A novel detection scheme utilizing two probe beams and two detectors for each chord results in reduced phase noise and increased time response [δb ∼ 1G with up to 3 MHz bandwidth]. First measurement results were obtained during the recent DIII-D experimental campaign. Simultaneous Faraday and density measurements have been successfully demonstrated and high-frequency, up to 100 kHz, Faraday-effect perturbations have been observed. Preliminary comparisons with EFIT are used to validate diagnostic performance. Principle of the diagnostic and first experimental results is presented.

  2. Research on reinforcement effect of vacuum preloading to treatment of the soft foundation

    Science.gov (United States)

    Li, bin; Li, maoji

    2017-12-01

    vacuum preloading method is a commonly used method to reinforce soft ground at present. Monitoring during construction stage is a dynamic monitoring, which is a standard to judge the quality of construction. This paper relies on the reclamation project of Tianjin Port Industrial Zone in North China, analyzed the monitoring purposes, monitoring method and collection data. Results had shown that vacuum preloading monitoring can make an accurate evaluation of construction quality during construction. The project practice can provide reference for similar projects.

  3. Spiral multiple-effect diffusion solar still coupled with vacuum-tube collector and heat pipe

    KAUST Repository

    Huang, Bin-Juine

    2015-04-01

    © 2015 Elsevier B.V. A novel solar still with spiral-shape multiple-effect diffusion unit is developed in the present study. The test results of a 14-effect unit coupled with vacuum-tube solar collector (absorber area 1.08m2) show that the highest daily pure water production is 40.6kgd-1. The measured highest productivity based on the area of glass cover, solar absorber, and evaporating surface is 34.7, 40.6, and 7.96kgm-2d-1, respectively, which are much higher than the published results. The measured solar distillation efficiency is 2.0-3.5. The performance enhancement results mainly from the lateral diffusion process in the spiraled still cell. The vapor flow generated by heat input can flow freely and laterally through the spiral channel down to the end when solar heat input is high. Besides, the larger evaporating and condensing area at the outer cell may increase heat and mass transfer at the outer cell.

  4. Multiple-effect diffusion solar still coupled with a vacuum-tube collector and heat pipe

    KAUST Repository

    Chong, Tze-Ling

    2014-08-01

    The present study develops a multiple-effect diffusion solar still (MEDS) with a bended-plate design in multiple-effect diffusion unit (MDU) to solve the peel-off problem of wick material. The MDU is coupled with a vacuum-tube solar collector to produce a high temperature gradient for high productivity. A heat pipe is used to transfer the solar heat to the MDU. A prototype MEDS-1L was built and tested outdoors. Four performance indexes are proposed for the performance evaluation of MEDS, including daily pure water production per unit area of glass cover, solar absorber, and evaporating surface (Mcov, Msol, Mevp, respectively), and solar distillation efficiency Rcov. The outdoor test results of MEDS-1L show that the solar collector supply temperature Th reaches 100°C at solar radiation 800Wm-2. The highest Mcov is 23.9kgm-2d-1 which is about 29% higher than the basin-type MEDS [11]. The highest value is 25.9kgm-2d-1 for Msol and 2.79kgm-2d-1 for Mevp. The measured Rcov is 1.5-2.44, higher than the basin-type MEDS (1.45-1.88). The Mcov, Msol, Mevp and Rcov of MEDS-1L are all higher than the theoretical calculation of a MEDS with a flat-plate solar collector coupled with a heat pipe (MEDS-FHP) [17].© 2014 Elsevier B.V.

  5. THE EFFECTS OF WATER TEMPERATURE REGIME FLUCTUATIONS ON THE EMBRYONIC DEVELOPMENT OF SILVER CARP (HYPOPHTHALMICHTHYS MOLITRIX

    Directory of Open Access Journals (Sweden)

    А. Vodyanitskyi

    2015-03-01

    Full Text Available Purpose. To determine the effect of temperature regime fluctuations on the development of silver carp embryos, as well as the activity of enzymatic reactions in fish eggs. Methodology. The studies were conducted at the experimental station of the Institute of Hydrobiology of Bila Tserkov, Ukrainian National Academy of Sciences, from June to July. The biological materials were silver carp eggs, embryos and larvae. The dissolved oxygen content was determined using the Winkler method at four o’clock in the morning. Alkalinity phosphatase and LDG activity were determined using a set of reagents «Alkalinity phosphatase» and «LDG» (Phyllis diagnosis, Ukraine. SDH activity was determined by Vexy. The activity of Na, K-Mg-dependent-activated ATPase was determined as growth of inorganic phosphorus in the incubation medium by Kindratova M.N. et al. Protease activity was determined using immune enzymatic method of Tyurina et al. The obtained results were processed statistically in Statistica 5.5, Epaprobit analysis was used for calculating LC/EC values (Version 1.5. Findings The results showed that a delay of embryonic stages of development occur, the number of abnormal embryos increases, and the reproduction efficiency of fish reduces with an increase in water temperature and decrease in the dissolved oxygen content in water. The temperature factor had a significant effect on the activity of key enzymes, in particular the energetic metabolism changed from aerobic to anaerobic. Originality. It was found a negative effect of abiotic factors of water medium and drastic fluctuations in water temperature and gas regime of water bodies on the course of embryogenesis of silver carp that is especially important in the conditions of climate change. Practical value. The obtained results showed that the level of optimum and unfavorable environmental factors during the change of embryonic stages in embryonic and larval fish can be established based on the

  6. Effects of Barometric Fluctuations on Well Water-Level Measurements and Aquifer Test Data

    Energy Technology Data Exchange (ETDEWEB)

    FA Spane, Jr.

    1999-12-16

    The Pacific Northwest National Laboratory, as part of the Hanford Groundwater Monitoring Project, examines the potential for offsite migration of contamination within underlying aquifer systems. Well water-level elevation measurements from selected wells within these aquifer systems commonly form the basis for delineating groundwater-flow patterns (i.e., flow direction and hydraulic gradient). In addition, the analysis of water-level responses obtained in wells during hydrologic tests provides estimates of hydraulic properties that are important for evaluating groundwater-flow velocity and transport characteristics. Barometric pressure fluctuations, however, can have a discernible impact on well water-level measurements. These barometric effects may lead to erroneous indications of hydraulic head within the aquifer. Total hydraulic head (i.e., sum of the water-table elevation and the atmospheric pressure at the water-table surface) within the aquifer, not well water-level elevation, is the hydrologic parameter for determining groundwater-flow direction and hydraulic gradient conditions. Temporal variations in barometric pressure may also adversely affect well water-level responses obtained during hydrologic tests. If significant, adjustments or removal of these barometric effects from the test-response record may be required for quantitative hydraulic property determination. This report examines the effects of barometric fluctuations on well water-level measurements and evaluates adjustment and removal methods for determining areal aquifer head conditions and aquifer test analysis. Two examples of Hanford Site unconfined aquifer tests are examined that demonstrate barometric response analysis and illustrate the predictive/removal capabilities of various methods for well water-level and aquifer total head values. Good predictive/removal characteristics were demonstrated with best corrective results provided by multiple-regression deconvolution methods.

  7. Effect of mesh-peel ply variation on mechanical properties of E-glas composite by infusion vacuum method

    Science.gov (United States)

    Abdurohman, K.; Siahaan, Mabe

    2018-04-01

    Composite materials made of glass fiber EW-135 with epoxy lycal resin with vacuum infusion method have been performed. The dried glass fiber is arranged in a mold then connected to a vacuum machine and a resin tube. Then, the vacuum machine is turned on and at the same time the resin is sucked and flowed into the mold. This paper reports on the effect of using mesh- peel ply singles on upper-side laminates called A and the effect of using double mesh-peel ply on upper and lower-side laminates call B with glass fiber arrangement is normal and ± 450 in vacuum infusion process. Followed by the manufacture of tensile test specimen and tested its tensile strength with universal test machine 100kN Tensilon RTF 2410, at room temperature with constant crosshead speed. From tensile test results using single and double layers showed that double mesh-peel ply can increase tensile strength 14% and Young modulus 17%.

  8. Noncommutative geometry and the standard model vacuum

    International Nuclear Information System (INIS)

    Barrett, John W.; Dawe Martins, Rachel A.

    2006-01-01

    The space of Dirac operators for the Connes-Chamseddine spectral action for the standard model of particle physics coupled to gravity is studied. The model is extended by including right-handed neutrino states, and the S 0 -reality axiom is not assumed. The possibility of allowing more general fluctuations than the inner fluctuations of the vacuum is proposed. The maximal case of all possible fluctuations is studied by considering the equations of motion for the vacuum. While there are interesting nontrivial vacua with Majorana-type mass terms for the leptons, the conclusion is that the equations are too restrictive to allow solutions with the standard model mass matrix

  9. Correcting Detector Efficiency Effects in Event-by-Event Net-Proton Fluctuations

    CERN Document Server

    Peters, Michael

    2016-01-01

    Measurements of fluctuations of conserved quantities give valuable information on the susceptibilities of the nuclear matter produced in a heavy-ion collision, and could in principle be used to distinguish QGP from hadronic matter. However, measurements of the cumulants of conserved-quantity distributions are affected by the detector efficiency, which must be accounted for in order to ensure accuracy. Following the development of a toy model that simulates detector efficiency effects on net-proton number, various correction methods, including those developed by A. Bzdak and V. Koch, were implemented and tested in a wide range of conditions. We find that the first four cumulants of net-proton-number distribution can be accurately reproduced by the Koch-Bzdak corrections with reasonable input statistics. Various methods of correcting for $p_T$ dependence of detector efficiency are also explored.

  10. Effects of magnetic geometry, fluctuations, and electric fields on confinement in the Advanced Toroidal Facility

    International Nuclear Information System (INIS)

    Isler, R.C.; Aceto, S.; Baylor, L.R.; Bigelow, T.S.; Bell, G.L.; Bell, J.D.; Carreras, B.A.; Colchin, R.J.; Crume, E.C.; Dominguez, N.; Dory, R.A.; Dunlap, J.L.; Dyer, G.R.; England, A.C.; Gandy, R.F.; Glowienka, J.C.; Hanson, G.R.; Harris, J.H.; Hiroe, S.; Horton, L.D.; Jernigan, T.C.; Ji, H.; Langley, R.A.; Lee, D.K.; Likin, K.M.; Lyon, J.F.; Ma, C.H.; Morimoto, S.; Murakami, M.; Okada, H.; Qualls, A.L.; Rasmussen, D.A.; Rome, J.A.; Sato, M.; Schwelberger, J.G.; Shats, M.G.; Simpkins, J.E.; Thomas, C.E.; Uckan, T.; Wade, M.R.; Wilgen, J.B.; Wing, W.R.; Yamada, H.; Zielinski, J.J.

    1992-01-01

    Recent experiments in the Advanced Toroidal Facility (ATF) [Fusion Technol. 10, 179 (1986)] have been directed toward investigations of the basic physics mechanisms that control confinement in this device. Measurements of the density fluctuations throughout the plasma volume have provided indications for the existence of theoretically predicted dissipative trapped electron and resistive interchange instabilities. These identifications are supported by results of dynamic configuration scans of the magnetic fields during which the magnetic well volume, shear, and fraction of confined trapped particles are changed continuously. The influence of magnetic islands on the global confinement has been studied by deliberately applying error fields which strongly perturb the nested flux-surface geometry, and the effects of electric fields have been investigated by means of biased limiter experiments

  11. The effect of disorder and fluctuations on the magnetotransport of a double-exchange ferromagnet (abstract)

    International Nuclear Information System (INIS)

    Byers, J.M.

    1996-01-01

    The discovery of colossal magnetoresistance (CMR) in the doped perovskite manganites has reawakened interest in the double-exchange mechanism proposed to Zener. To account for the close relation between ferromagnetism and metallic transport in lanthanum manganites doped with divalent cation (Ca, Sr, Ba) Zener claimed that an electron could delocalize on lattice of spins and still conform to Hund close-quote s Rule if a ferromagnetic coupling between spins were mediated by that same electron. Thus, the onset of metallic behavior (delocalization) is intimately linked to ferromagnetic ordering of the spin lattice. Clearly, the double-exchange mechanism provides some necessary physics but is not sufficient in explaining the key mystery of the CMR materials: What causes the large peak in the resistivity vs. temperature and why is it removed by an applied magnetic field. The effect of disorder and fluctuations on the double-exchange mechanism may provide the answers. Several sources of disorder in these materials act to form a mobility edge via Anderson localization: intrinsic divalent/trivalent cation disorder, off-diagonal disorder caused by the spin lattice and oxygen vacancy disorder. A mean-field calculation reveals that below the Curie temperature those carriers aligned opposite to the magnetization experience a narrowing band as the temperature is reduced. Fermi glass behavior is induced in this minority carrier band by the Fermi level falling below the mobility edge. However, the mean-field result does not contain a peak in resistivity since the majority carrier band does not behave as a Fermi glass and effectively open-quote open-quote shorts out close-quote close-quote the more resistive minority conduction channel. The formation of the resistivity peak requires the inclusion of ferromagnetic fluctuations above the Curie temperature that tend to open-quote open-quote mix close-quote close-quote the two conduction channels. (Abstract Truncated)

  12. Effect of duct bias on transport of vacuum arc plasmas through curved magnetic filters

    International Nuclear Information System (INIS)

    Anders, A.; Anders, S.; Brown, I.G.

    1994-01-01

    The plasma output of a 90 degree magnetic macroparticle filter of vacuum arc plasma was monitored by a Langmuir probe as a function of bias of the duct wall and guiding magnetic field. Maximum plasma transport through the filter was found at a positive bias of about 20 V. A relatively small magnetic field of 10--30 mT is sufficient for effective guiding of the plasma, and further increase of the guiding field improves the filter efficiency only gradually. The potential of a floating duct changes from negative to positive when the guiding field is increased. This can be explained by the balance of electron and ion flux transverse to the magnetic field. Saturation in the plasma output at high guiding field (>120 mT) is observed for carbon but not for heavy elements. The transport of plasma through bent ducts is made possible by the magnetic pressure of the guiding field, and by sheath and space-charge electric fields

  13. Vacuum-and-solvent-free fabrication of organic semiconductor layers for field-effect transistors

    Science.gov (United States)

    Matsushima, Toshinori; Sandanayaka, Atula S. D.; Esaki, Yu; Adachi, Chihaya

    2015-09-01

    We demonstrate that cold and hot isostatic pressing (CIP and HIP) is a novel, alternative method for organic semiconductor layer fabrication, where organic powder is compressed into a layer shape directly on a substrate with 200 MPa pressure. Spatial gaps between powder particles and the other particles, substrates, or electrodes are crushed after CIP and HIP, making it possible to operate organic field-effect transistors (OFETs) containing the compressed powder as the semiconductor. The CIP-compressed powder of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) had a hole mobility of (1.6 ± 0.4) × 10-2 cm2/Vs. HIP of C8-BTBT powder increased the hole mobility to an amorphous silicon-like value (0.22 ± 0.07 cm2/Vs) because of the growth of the C8-BTBT crystallites and the improved continuity between the powder particles. The vacuum and solution processes are not involved in our CIP and HIP techniques, offering a possibility of manufacturing OFETs at low cost.

  14. Effect of High Solenoidal Magnetic Fields on Breakdown Voltages of High Vacuum 805 MHz Cavities

    CERN Document Server

    Moretti, A; Geer, S; Qian, Z

    2004-01-01

    The demonstration of muon ionization cooling by a large factor is necessary to demonstrate the feasilibility of a collider or neutrino factory. An important cooling experiment, MICE [1], has been proposed to demonstrate 10 % cooling which will validate the technology. Ionization cooling is accomplished by passing a high-emittance beam in a multi-Tesla solenoidal channel alternately through regions of low Z material and very high accelerating RF Cavities. To determine the effect of very large solenoidal magnetic fields on the generations of Dark current, X-Rays and breakdown Voltage gradients of vacuum RF cavities, a test facility has been established at Fermilab in Lab G. This facility consists of a 12 MW 805 MHz RF station, and a large bore 5 T solenoidal superconducting magnet containing a pill box type Cavity with thin removable window apertures allowing dark current studies and breakdown studies of different materials. The results of this study will be presented. The study has shown that the peak achievab...

  15. The effect of cinnamon bark (Cinnamomum burmanii) essential oil microcapsules on vacuumed ground beef quality

    Science.gov (United States)

    Brilliana, I. N.; Manuhara, G. J.; Utami, R.; Khasanah, L. U.

    2017-04-01

    Ground beef has a short shelf life because it is susceptible to damage due to microbial contamination and lipid oxidation. So some sort of preservation method such as refrigerated storage, vacuum packaging or natural preservative addition is needed to extend the shelf life of ground beef. A natural preservative that can be used as a food preservative is the cinnamon bark (Cinnamomum burmanii) essential oil microcapsules. The aim of the research was to determine the influence of a cinnamon bark essential oil microcapsules (0%;0.5% and 1% w/w of the ground beef) on the Total Plate Count (TPC), Thiobarbituric Acid (TBA), pH and color of ground beef during refrigerated storage (4±1°C). The result showed that cinnamon bark essential oil microcapsules affected the TPC, TBA, pH and color of ground beef. The addition of the cinnamon bark essential oil microcapsules on ground beef can inhibit microbial growth, inhibit lipid oxidation, inhibit discoloration and lowering pH of fresh ground beef during refrigerated storage compared to the control sample. The higher of the microcapsules were added, the higher the inhibition of microbial growth, lipid oxidation and discoloration of ground beef, indicating better preservation effects.

  16. [The method for studying of the "magnetic vacuum" effect on color memory in humans].

    Science.gov (United States)

    Bingi, V N; Zarutskiĭ, A A; Kapranov, S V; Kotel'nikov, S N; Miliaev, V A; Sarimov, R M

    2005-01-01

    The method for studying the effects of weak magnetic fields and "magnetic vacuum" on the psychophysiological state of a human organism is proposed. This method includes the system of the exposure of a human organism to uniform constant and alternating magnetic fields and the system of computerized psychological tests. The influence of the weakening of constant magnetic field on the psychophysiological state of human organisms was studied. The short-term color memory and reaction rates of 30 subjects have been examined in the local geomagnetic field and in a magnetic field which was reduced in 10 and more times. Statistically significant differences in the color memory test was found in the magnetic field 4 +/- 1 microT in comparison with the results in the geomagnetic field. In the magnetic field 0 +/- 1 microT, slight impairment of color memory was found. Preliminary results in the test of reaction rates showed the tendency to slowing down the reaction rates in the weakened magnetic fields.

  17. Traversable Lorentzian wormholes in the vacuum low energy effective string theory in Einstein and Jordan frames

    International Nuclear Information System (INIS)

    Nandi, K.K.; Zhang Yuanzhong

    2004-01-01

    Three new classes (II-IV) of solutions of the vacuum low energy effective string theory in four dimensions are derived. Wormhole solutions are investigated in those solutions including the class I case both in the Einstein and in the Jordan (string) frame. It turns out that, of the eight classes of solutions investigated (four in the Einstein frame and four in the corresponding string frame), massive Lorentzian traversable wormholes exist in five classes. Nontrivial massless limit exists only in class I Einstein frame solution while none at all exists in the string frame. An investigation of test scalar charge motion in the class I solution in the two frames is carried out by using the Plebanski-Sawicki theorem. A curious consequence is that the motion around the extremal zero (Keplerian) mass configuration leads, as a result of scalar-scalar interaction, to a new hypothetical 'mass' that confines test scalar charges in bound orbits, but does not interact with neutral test particles

  18. Vacuum-and-solvent-free fabrication of organic semiconductor layers for field-effect transistors

    Science.gov (United States)

    Matsushima, Toshinori; Sandanayaka, Atula S. D.; Esaki, Yu; Adachi, Chihaya

    2015-01-01

    We demonstrate that cold and hot isostatic pressing (CIP and HIP) is a novel, alternative method for organic semiconductor layer fabrication, where organic powder is compressed into a layer shape directly on a substrate with 200 MPa pressure. Spatial gaps between powder particles and the other particles, substrates, or electrodes are crushed after CIP and HIP, making it possible to operate organic field-effect transistors (OFETs) containing the compressed powder as the semiconductor. The CIP-compressed powder of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) had a hole mobility of (1.6 ± 0.4) × 10–2 cm2/Vs. HIP of C8-BTBT powder increased the hole mobility to an amorphous silicon-like value (0.22 ± 0.07 cm2/Vs) because of the growth of the C8-BTBT crystallites and the improved continuity between the powder particles. The vacuum and solution processes are not involved in our CIP and HIP techniques, offering a possibility of manufacturing OFETs at low cost. PMID:26416434

  19. Effect of high solenoidal magnetic fields on breakdown voltages of high vacuum 805 MHz cavities

    International Nuclear Information System (INIS)

    Moretti, A.; Bross, A.; Geer, S.; Qian, Z.; Norem, J.; Li, D.; Zisman, M.; Torun, Y.; Rimmer, R.; Errede, D.

    2005-01-01

    There is an on going international collaboration studying the feasibility and cost of building a muon collider or neutrino factory [1,2]. An important aspect of this study is the full understanding of ionization cooling of muons by many orders of magnitude for the collider case. An important muon ionization cooling experiment, MICE [3], has been proposed to demonstrate and validate the technology that could be used for cooling. Ionization cooling is accomplished by passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF Cavities within a multi-Tesla solenoidal field. To determine the effect of very large solenoidal magnetic fields on the generation of dark current, x-rays and on the breakdown voltage gradients of vacuum RF cavities, a test facility has been established at Fermilab in Lab G. This facility consists of a 12 MW 805 MHz RF station and a large warm bore 5 T solenoidal superconducting magnet containing a pill box type cavity with thin removable window apertures. This system allows dark current and breakdown studies of different window configurations and materials. The results of this study will be presented. The study has shown that the peak achievable accelerating gradient is reduced by a factor greater than 2 when solenoidal field of greater than 2 T are applied to the cavity

  20. The effect of vacuum packaging on histamine changes of milkfish sticks at various storage temperatures.

    Science.gov (United States)

    Kung, Hsien-Feng; Lee, Yi-Chen; Lin, Chiang-Wei; Huang, Yu-Ru; Cheng, Chao-An; Lin, Chia-Min; Tsai, Yung-Hsiang

    2017-10-01

    The effects of polyethylene packaging (PEP) (in air) and vacuum packaging (VP) on the histamine related quality of milkfish sticks stored at different temperatures (-20°C, 4°C, 15°C, and 25°C) were studied. The results showed that the aerobic plate count (APC), pH, total volatile basic nitrogen (TVBN), and histamine contents increased as storage time increased when the PEP and VP samples were stored at 25°C. At below 15°C, the APC, TVBN, pH, and histamine levels in PEP and VP samples were retarded, but the VP samples had considerably lower levels of APC, TVBN, and histamine than PEP samples. Once the frozen fish samples stored at -20°C for 2 months were thawed and stored at 25°C, VP retarded the increase of histamine in milkfish sticks as compared to PEP. In summary, this result suggested the milkfish sticks packed with VP and stored below 4°C could prevent deterioration of product quality and extend shelf-life. Copyright © 2017. Published by Elsevier B.V.

  1. The effect of vacuum-assisted closure in bacterial clearance of the infected abdomen.

    Science.gov (United States)

    Pliakos, Ioannis; Michalopoulos, Nikolaos; Papavramidis, Theodossis S; Arampatzi, Stergiani; Diza-Mataftsi, Eudoxia; Papavramidis, Spiros

    2014-02-01

    Laparostomy with vacuum-assisted closure (VAC) plays an important role in improving survival in the presence of abdominal infection. We conducted a study of the qualitative changes in the bacterial flora of the peritoneal cavity in patients with severe abdominal infection treated with laparostomy and a VAC device. Thirty-nine patients with severe abdominal infection treated with abdominal opening and VAC were registered in a clinical study. When an incidence of 53.8% of hospital-acquired peritoneal infection (HAPI) was found in the study patient population, it was decided to divide the patients in two groups according to whether or not they developed a HAPI. The patients' outcomes were then analyzed. The durations of abdominal opening (p=0.04), length of stay in the intensive care unit (ICU) (p=0.01), and of hospitalization (p=0.04) were significantly greater in patients with HAPI than in those without it, whereas mortality did not differ on the basis of these three variables. Superinfection is common in laparostomy done with a VAC device for managing severe abdominal infection. The data in the present study show that VAC does not alter the quality of the bacterial burden in primary abdominal contamination, nor does it seem to prevent a high incidence of HAPI. However, VAC is as effective in reducing mortality among patients with HAPI as among those without it.

  2. Effect of Grinding at Modified Atmosphere or Vacuum on Browning, Antioxidant Capacities, and Oxidative Enzyme Activities of Apple.

    Science.gov (United States)

    Kim, Ah-Na; Lee, Kyo-Yeon; Kim, Hyun-Jin; Chun, Jiyeon; Kerr, William L; Choi, Sung-Gil

    2018-01-01

    This study evaluated the effects of grinding at atmospheric pressure (control), under vacuum (∼2.67 kPa), or with modified atmosphere (N 2 and CO 2 ) on the browning, antioxidant activity, phenolics, and oxidative enzyme activity of apples as a function of time. The control group was affected most, showing distinct browning and losing most of the antioxidant activity and concentrations of the main phenolic compounds. The modified atmosphere groups retained color, antioxidant activity, and phenolic compounds better than the control group. Least changes were obtained with vacuum grinding, particularly in terms of preventing enzymatic browning and oxidation of antioxidants apples. At 12 h after grinding, vacuum-ground apples retained total phenolic contents 5.32, 1.54, and 1.49 times higher than control, nitrogen gas, and carbon dioxide gas-ground samples, respectively. The oxidative enzyme activity, including that of polyphenol oxidase and peroxidase, decreased in the control and modified atmosphere group, but they were maintained in the samples ground under the vacuum. In this study, we found that grinding with modified atmosphere or vacuum conditions could effectively prevent browning as well as loss of phenolic compounds and antioxidant activity of ground apples. These results can help scientists and engineers build better grinding systems for retaining nutrient and quality factors of ground apples. In addition, these results may be useful to other fruit and vegetable industries that wish to retain fresh-like quality and nutritional value during grinding and storage. © 2017 Institute of Food Technologists®.

  3. Effects of vole fluctuations on the population dynamics of the barn owl Tyto alba

    NARCIS (Netherlands)

    Klok, T.C.; Roos, A.M.

    2007-01-01

    Many predator species feed on prey that fluctuates in abundance from year to year. Birds of prey can face large fluctuations in food abundance i.e. small mammals, especially voles. These annual changes in prey abundance strongly affect the reproductive success and mortality of the individual

  4. Ionic screening effect on low-frequency drain current fluctuations in liquid-gated nanowire FETs

    International Nuclear Information System (INIS)

    Lu, Ming-Pei; Vire, Eric; Montès, Laurent

    2015-01-01

    The ionic screening effect plays an important role in determining the fundamental surface properties within liquid–semiconductor interfaces. In this study, we investigated the characteristics of low-frequency drain current noise in liquid-gated nanowire (NW) field effect transistors (FETs) to obtain physical insight into the effect of ionic screening on low-frequency current fluctuation. When the NW FET was operated close to the gate voltage corresponding to the maximum transconductance, the magnitude of the low-frequency noise for the NW exposed to a low-ionic-strength buffer (0.001 M) was approximately 70% greater than that when exposed to a high-ionic-strength buffer (0.1 M). We propose a noise model, considering the charge coupling efficiency associated with the screening competition between the electrolyte buffer and the NW, to describe the ionic screening effect on the low-frequency drain current noise in liquid-gated NW FET systems. This report not only provides a physical understanding of the ionic screening effect behind the low-frequency current noise in liquid-gated FETs but also offers useful information for developing the technology of NW FETs with liquid-gated architectures for application in bioelectronics, nanosensors, and hybrid nanoelectronics. (paper)

  5. Various Parameters of the Flowing Part of a Cylindrical Molecular Vacuum Pump Effecting on Its Characteristics

    Directory of Open Access Journals (Sweden)

    K. E. Demikhov

    2015-01-01

    Full Text Available In the context of modern industry the molecular vacuum pumps (MVP are widely used. The analyzed current market of vacuum technology enables drawing a conclusion that this equipment holds one of the leading positions among the high-vacuum facilities of pumping due to their advantages such as insensitivity to the atmosphere breakthrough, ability to pump out heavy gases quickly, rapid start-up time, and oil-free pumping.The earlier developed authors’ mathematical model and calculation program are used to assess the influence efficiency of the key geometrical parameters of flowing part of the cylindrical molecular pump on its main characteristics. The obtained dependences allow us to solve a relevant, but not completely resolved as yet problem of optimizing the high-vacuum pumping facilities in case of their operation in a wide range of pressures on the suction side.The paper presents graphs of the pumping speed and ratio of the cylindrical vacuum molecular pump pressures versus various parameters of the flowing part, such as the angle of inclination of the helix, the relative diameter and the number of helical starts. Conclusions are drawn.

  6. The influence of the edge density fluctuations on electron cyclotron wave beam propagation in tokamaks

    DEFF Research Database (Denmark)

    Bertelli, N.; Balakin, A.A.; Westerhof, E.

    2010-01-01

    are estimated in a vacuum beam propagation between the edge density layer and the EC resonance absorption layer. Consequences on the EC beam propagation are investigated by using a simplified model in which the density fluctuations are described by a single harmonic oscillation. In addition, quasi......A numerical analysis of the electron cyclotron (EC) wave beam propagation in the presence of edge density fluctuations by means of a quasi-optical code [Balakin A. A. et al, Nucl. Fusion 48 (2008) 065003] is presented. The effects of the density fluctuations on the wave beam propagation...

  7. Quantitative study of fluctuation effects by fast lattice Monte Carlo simulations: Compression of grafted homopolymers

    International Nuclear Information System (INIS)

    Zhang, Pengfei; Wang, Qiang

    2014-01-01

    Using fast lattice Monte Carlo (FLMC) simulations [Q. Wang, Soft Matter 5, 4564 (2009)] and the corresponding lattice self-consistent field (LSCF) calculations, we studied a model system of grafted homopolymers, in both the brush and mushroom regimes, in an explicit solvent compressed by an impenetrable surface. Direct comparisons between FLMC and LSCF results, both of which are based on the same Hamiltonian (thus without any parameter-fitting between them), unambiguously and quantitatively reveal the fluctuations/correlations neglected by the latter. We studied both the structure (including the canonical-ensemble averages of the height and the mean-square end-to-end distances of grafted polymers) and thermodynamics (including the ensemble-averaged reduced energy density and the related internal energy per chain, the differences in the Helmholtz free energy and entropy per chain from the uncompressed state, and the pressure due to compression) of the system. In particular, we generalized the method for calculating pressure in lattice Monte Carlo simulations proposed by Dickman [J. Chem. Phys. 87, 2246 (1987)], and combined it with the Wang-Landau–Optimized Ensemble sampling [S. Trebst, D. A. Huse, and M. Troyer, Phys. Rev. E 70, 046701 (2004)] to efficiently and accurately calculate the free energy difference and the pressure due to compression. While we mainly examined the effects of the degree of compression, the distance between the nearest-neighbor grafting points, the reduced number of chains grafted at each grafting point, and the system fluctuations/correlations in an athermal solvent, the θ-solvent is also considered in some cases

  8. Effect of periodic environmental fluctuations on the Pearl-Verhulst model

    International Nuclear Information System (INIS)

    Rogovchenko, Svitlana P.; Rogovchenko, Yuri V.

    2009-01-01

    We address the effect of periodic environmental fluctuations on the Pearl-Verhulst model in population dynamics and clarify several important issues very actively discussed in the recent papers by Lakshmi [Lakshmi BS. Oscillating population models. Chaos Solitons and Fractals 2003;16:183-6; Lakshmi BS. Population models with time dependent parameters. Chaos Solitons and Fractals 2005;26:719-21], Leach and Andriopoulos [Leach PGL, Andriopoulos K. An oscillatory population model. Chaos Solitons and Fractals 2004;22:1183-8], Swart and Murrell [Swart JH, Murrell HC. An oscillatory model revisited. Chaos Solitons and Fractals 2007;32:1325-7]. Firstly, we review general results regarding existence and properties of periodic solutions and examine existence of a unique positive asymptotically stable periodic solution of a non-autonomous logistic differential equation when r(t)>0. Proceeding to the case where r(t) is allowed to take on negative values, we consider a modified Pearl-Verhulst equation because, as emphasized by Hallam and Clark [Hallam TG, Clark CE. Non-autonomous logistic equations as models of populations in deteriorating environment. J Theor Biol 1981;93:303-11], use of the classic one leads to paradoxical biological conclusions. For a modified logistic equation with ω-periodic coefficients, we establish existence of a unique asymptotically stable positive periodic solution with the same period. Special attention is paid to important cases where time average of the intrinsic growth rate is non-positive. Results of computer simulation demonstrating advantages of a modified equation for modeling periodic environmental fluctuations are presented.

  9. The effect of Gaussian white noise on the fractality of fluctuations in the plasma of a symmetrical discharge

    International Nuclear Information System (INIS)

    Stan, Cristina; Cristescu, Cristina Maria; Alexandroaei, D.; Cristescu, C.P.

    2014-01-01

    Highlights: •We study the white Gaussian noise effect on the fractality of plasma fluctuations. •Multifractality strength is increased by the noise, at all inter-anode voltages. •New positive influence of noise resulting in an increasing of the predictability. •Identifying the fluctuations nature: chaotic or stochastic by multifractal analysis. •Noise changes the position of the maximum in the singularity spectra. - Abstract: In this work we investigate the influence of white Gaussian noise on the fluctuations in the plasma of a symmetrical discharge using multifractal detrended fluctuation analysis. We observe that in the range of noise intensity used in our study, the multifractality strength is increased by the noise, at all values of the inter-anode voltage, both for original and filtered time-series. This is interpreted as a new positive influence of noise because this effect can be understood as an increasing in the predictability on the dynamics in a time-series. A constructive influence of noise can appear only for fluctuations with underlying chaotic dynamics. The shuffling analysis demonstrates that the multifractality is purely a consequence of the correlations of the fluctuations. The noise influence is also observed in the change of the position of the maximum in the singularity spectra. The multifractal detrended cross correlation between light intensity and current intensity demonstrates that the fluctuations in both parameters are generated by the same physical processes though they are very different in nature: one is a local parameter and the other is a global one

  10. The extended Moran effect and large-scale synchronous fluctuations in the size of great tit and blue tit populations

    NARCIS (Netherlands)

    Saether, B-E.; Engen, S.; Grøtan, V.; Fiedler, W.; Matthysen, E.; Visser, M.E.; Wright, J.; Møller, A.P.; Adriaensen, F.; van Balen, H.; Balmer, D.; Mainwaring, M.C.; McCleery, R.; Pampus, M.; Winkel, W.

    2007-01-01

    1. Synchronous fluctuations of geographically separated populations are in general explained by the Moran effect, i.e. a common influence on the local population dynamics of environmental variables that are correlated in space. Empirical support for such a Moran effect has been difficult to provide,

  11. Vacuum gauges

    International Nuclear Information System (INIS)

    Power, B.D.; Priestland, C.R.D.

    1978-01-01

    This invention relates to vacuum gauges, particularly of the type known as Penning gauges, which are cold cathode ionisation gauges, in which a magnetic field is used to lengthen the electron path and thereby increase the number of ions produced. (author)

  12. Effects of vacuum processing erbium dideuteride/ditritide films deposited on chromium underlays on copper substrates

    International Nuclear Information System (INIS)

    Provo, J.L.

    1978-01-01

    Thin films of erbium dideuteride/ditritide were experimentally produced on chromium underlays deposited on copper substrates. The chromium underlay is required to prevent erbium occluder/copper substrate alloying which inhibits hydriding. Data taken has shown that vacuum processing affects the erbium/chromium/copper interaction. With an in situ process in which underlay/occluder films are vacuum deposited onto copper substrates and hydrided with no air exposure between these steps, data indicates a minimum of 1500A of chromium is required for optimum hydriding. If films are vacuum deposited as above and air-exposed before hydriding, a minimum of 3000A of chromium was shown to be required for equivalent hydriding. Data suggests that the activation step (600 0 C for 1 hour) required for hydriding the film of the second type is responsible for the difference observed. Such underlay thickness parameters are important, with regard to heat transfer considerations in thin hydride targets used for neutron generation

  13. The effect of random dopant fluctuation on threshold voltage and drain current variation in junctionless nanotransistors

    International Nuclear Information System (INIS)

    Rezapour, Arash; Rezapour, Pegah

    2015-01-01

    We investigate the effect of dopant random fluctuation on threshold voltage and drain current variation in a two-gate nanoscale transistor. We used a quantum-corrected technology computer aided design simulation to run the simulation (10000 randomizations). With this simulation, we could study the effects of varying the dimensions (length and width), and thicknesses of oxide and dopant factors of a transistor on the threshold voltage and drain current in subthreshold region (off) and overthreshold (on). It was found that in the subthreshold region the variability of the drain current and threshold voltage is relatively fixed while in the overthreshold region the variability of the threshold voltage and drain current decreases remarkably, despite the slight reduction of gate voltage diffusion (compared with that of the subthreshold). These results have been interpreted by using previously reported models for threshold current variability, load displacement, and simple analytical calculations. Scaling analysis shows that the variability of the characteristics of this semiconductor increases as the effects of the short channel increases. Therefore, with a slight increase of length and a reduction of width, oxide thickness, and dopant factor, we could correct the effect of the short channel. (paper)

  14. Efficacy and haemodynamic effects of vacuum-assisted closure for post-sternotomy mediastinitis in children.

    Science.gov (United States)

    Takahara, Shingo; Sai, Sadahiro; Kagatani, Tomoaki; Konishi, Akinobu

    2014-10-01

    Post-sternotomy mediastinitis is a significant morbidity with controversial management. Vacuum-assisted closure (VAC) has been used to treat mediastinitis, with many reports documenting its efficacy and feasibility, particularly in adults. However, its use is not prevalent in the paediatric population because of concerns that it may deteriorate haemodynamics. This study aimed to evaluate outcomes and effects of VAC on the haemodynamics of paediatric patients with post-sternotomy mediastinitis. Six patients were treated with VAC between April 2005 and March 2013. We retrospectively investigated their profiles, clinical outcomes and haemodynamic changes, including mean blood pressure (MBP), mean heart rate (MHR), urinary output, amount of diuretics and vasoactive-inotropic score (VIS), before and after VAC initiation. The median age and body weight of patients were 6.4 months and 4.5 kg, respectively. Three patients (50%) had single ventricular physiology. The median VAC duration was 12 days. One patient died of pulmonary venous obstruction after mediastinitis was cured. The average MBPs in every 8-h period were examined, and there were no significant changes (P = 0.773); the average MHRs were examined in the same manner and they decreased significantly after initiation of VAC (P = 0.032). Only 2 patients required vasoactive agents. The VIS did not change in 1 patient and decreased in the other. The mean amount of diuretics administered and urinary output per body weight did not change significantly (P = 0.395 and 0.273, respectively). In conclusion, the haemodynamics of children were not significantly affected by the negative pressure of VAC, indicating that this therapy may be safe and effective for post-sternotomy mediastinitis, even in small children with complex cardiac anomalies. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  15. Effects of dust grain charge fluctuation on obliquely propagating dust-acoustic potential in magnetized dusty plasmas

    International Nuclear Information System (INIS)

    Mamun, A.A.; Hassan, M.H.A.

    1999-05-01

    Effects of dust grain charge fluctuation, obliqueness and external magnetic field on finite amplitude dust-acoustic solitary potential in a magnetized dusty plasma, consisting of electrons, ions and charge fluctuating dust grains, have been investigated by the reductive perturbation method. It has been shown that such a magnetized dusty plasma system may support dust-acoustic solitary potential on a very slow time scale involving the motion of dust grains, whose charge is self-consistently determined by local electron and ion currents. The effects of dust grain charge fluctuation, external magnetic field and obliqueness are found to modify the properties of this dust-acoustic solitary potential significantly. The implications of these results to some space and astrophysical dusty plasma systems, especially to planetary ring-systems and cometary tails, are briefly mentioned. (author)

  16. Fluctuation-dissipation theorem in general relativity and the cosmological constant

    International Nuclear Information System (INIS)

    Mottola, E.

    1992-01-01

    Vacuum fluctuations are an essential feature of quantum field theory. Yet, the smallness of the scalar curvature of our universe suggests that the zero-point energy associated with these fluctuations does not curve spacetime. A possible way out of this paradox is suggested by the fact that microscopic fluctuations are generally accompanied by dissipative behavior in macroscopic systems. The intimate relation between the two is expressed by a fluctuation-dissipation theorem which extends to general relativity. The connection between quantum fluctuations and dissipation suggests a mechanism for the conversion of coherent stresses in the curvature of space into ordinary matter or radiation, thereby relaxing the effective cosmological ''constant'' to zero over time. The expansion of the universe may be the effect of this time-asymmetric relaxation process

  17. The evaluation of effectiveness of 3DCA using vacuum bag(Vac-Lock) for patient immobilization device

    International Nuclear Information System (INIS)

    Lee, Young Chul; Lee, Chul Bin; Kang, No Hyun; Kim, Dong Euk; Lee, Jung Yong; Jeong, In Pyo

    2004-01-01

    Patient immobilization is crucial factor for radiation therapy. Generally, we have been used vacuum bag immobilization device(Vac-Lock) for whole body immobilization. In order to easily set up of vacuum bag(Vac-Lock), we made a 3DCA(3-Dimensional Conformal Accessory). The purpose of this study is evaluation of effectiveness of 3DCA using Vack-Lock for patient immobilization. We made 3DCA(3-Dimensional Conformal Accessory) tool of wooden boards. The reasons to choice of wooden boards are its easily handling nature and cheap expenses. (1) We reduced man power from 5-6 persons to 1 person to make immobilizations, (2) Shortened work time from 1 hour to within 10 minutes. (3) Avoid a collision to treatment gantry head. (4) Its shapes are smart and clean. We have made and used 3DCA(3-Dimensional Conformal Accessory) tool was very effective and convenience for the patients and users.

  18. Further comments on the effects of vacuum birefringence on the polarization of X-rays emitted from magnetic neutron stars

    Science.gov (United States)

    Chanan, G. A.; Novick, R.; Silver, E. H.

    1979-01-01

    The birefringence of the vacuum in the presence of strong (of the order of 1 teragauss) magnetic fields will in general affect the polarization of X-rays propagating through these fields. Two of the four Stokes parameters will vary so rapidly with wavelength as to be 'washed out' and unobservable, but the remaining two parameters will be unaffected. These results show that one conclusion of an earlier work is incorrect: Polarized X-ray emission from the surface of a magnetic neutron star will not in general be completely depolarized by the effects of vacuum birefringence. In particular, this birefringence has no effect on the linear polarization of cyclotron emission from the poles of magnetic neutron stars, and a similar result holds for synchrotron emission. More general cases of the propagation of polarized X-rays in magnetic fields are also discussed.

  19. Effect of arc behaviour on the temperature fluctuation of carbon electrode in DC arc discharge

    International Nuclear Information System (INIS)

    Liang, F; Tanaka, M; Choi, S; Watanabe, T

    2014-01-01

    Diffuse and multiple arc-anode attachment modes were observed in a DC arc discharge with a carbon electrode. During the arc discharge, the surface temperature of the electrode was successfully measured by two-colour pyrometry combined with a high-speed camera which employs appropriate band-pass filters. The relationship between the arc-anode attachment mode and the temperature fluctuation of electrode surface was investigated. The diffuse arc-anode attachment mode leads to relatively large temperature fluctuation on anode surface due to the rotation of the arc spot. In the case of diffuse mode, the purity of synthesized multi-wall carbon nanotube was deteriorated with temperature fluctuation

  20. Temperature fluctuation caused by coaxial-jet flow: Experiments on the effect of the velocity ratio R ⩾ 1

    International Nuclear Information System (INIS)

    Cao, Qiong; Li, Hongyuan; Lu, Daogang; Chang, Mu

    2017-01-01

    Highlights: • The effect on temperature fluctuation from velocity ratio was studied by experiment. • The distribution of time-averaged temperatures is the axial-symmetry in R ⩾ 1. • The region of intense temperature fluctuation in R = 1 is different from that of R > 1. • The intensity of temperature fluctuation under R > 1 is weaker than that of R = 1. - Abstract: The temperature fluctuation appears in the core outlet region due to the different of the temperature and velocity of the coolant, which can cause thermal stresses and the high-cycle thermal fatigue on solid boundaries. So, it is necessary to analyze the characteristics of the temperature fluctuation. In the present study, a comparative experiment was performed to analyze the effect on the temperature fluctuation caused by the coaxial-jet flow from the inlet cold and hot fluid velocity ratios (R ⩾ 1). In the condition of R ⩾ 1, the distribution of the time-averaged temperature is the axial-symmetry. In the cold fluid field, the temperature field is divided into four parts, including the first steady region, linear region, nonlinear region and the second steady region along the axial direction, while that is lack of the first steady state region in the hot fluid field. In the condition of R = 1, due to the velocity of the cold fluid is equivalent to that of the hot fluid, the cold fluid flow can be severely disturbed by the hot flow. The intense temperature fluctuation mainly distributed in the annular region at bottom region and the circular region in the upper region. While, in the condition of R > 1, the inertia of the cold fluid is larger than that of the hot fluid. The hot fluid will attach itself to the periphery of the cold fluid. The intense temperature fluctuation distributed in the annular region between the cold and hot fluid and the periphery of the hot fluid. However, the intensity of temperature fluctuation under R > 1 is weaker than that of R = 1.

  1. Temperature fluctuation caused by coaxial-jet flow: Experiments on the effect of the velocity ratio R ⩾ 1

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Qiong, E-mail: lian24111@163.com [Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy, North China Electric Power University, Beijing 102206 (China); Li, Hongyuan, E-mail: lihongyuan@ncepu.edu.cn [School of Control and Computer Engineering, North China Electric Power University, Beijing 102206 (China); Lu, Daogang, E-mail: ludaogang@ncepu.edu.cn [Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy, North China Electric Power University, Beijing 102206 (China); Chang, Mu, E-mail: changmu123@163.com [Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy, North China Electric Power University, Beijing 102206 (China)

    2017-04-01

    Highlights: • The effect on temperature fluctuation from velocity ratio was studied by experiment. • The distribution of time-averaged temperatures is the axial-symmetry in R ⩾ 1. • The region of intense temperature fluctuation in R = 1 is different from that of R > 1. • The intensity of temperature fluctuation under R > 1 is weaker than that of R = 1. - Abstract: The temperature fluctuation appears in the core outlet region due to the different of the temperature and velocity of the coolant, which can cause thermal stresses and the high-cycle thermal fatigue on solid boundaries. So, it is necessary to analyze the characteristics of the temperature fluctuation. In the present study, a comparative experiment was performed to analyze the effect on the temperature fluctuation caused by the coaxial-jet flow from the inlet cold and hot fluid velocity ratios (R ⩾ 1). In the condition of R ⩾ 1, the distribution of the time-averaged temperature is the axial-symmetry. In the cold fluid field, the temperature field is divided into four parts, including the first steady region, linear region, nonlinear region and the second steady region along the axial direction, while that is lack of the first steady state region in the hot fluid field. In the condition of R = 1, due to the velocity of the cold fluid is equivalent to that of the hot fluid, the cold fluid flow can be severely disturbed by the hot flow. The intense temperature fluctuation mainly distributed in the annular region at bottom region and the circular region in the upper region. While, in the condition of R > 1, the inertia of the cold fluid is larger than that of the hot fluid. The hot fluid will attach itself to the periphery of the cold fluid. The intense temperature fluctuation distributed in the annular region between the cold and hot fluid and the periphery of the hot fluid. However, the intensity of temperature fluctuation under R > 1 is weaker than that of R = 1.

  2. Study of the combined effect of spices and marination on beef meat vacuum packaged

    Directory of Open Access Journals (Sweden)

    DANIELA ISTRATI

    2011-12-01

    Full Text Available Fresh beef slices were marinated by immersion in marinades based on dry red wine, lime-tree honey, salt, spices and seasoning plants as thyme (Thymus vulgaris, marjoram (Majorana hortensis, garlic (Allium sativum and horseradish (Armoracia rusticana. Control samples were represented by raw meat without marination treatment but stored in the same conditions as marinated samples. After marination, meat pieces were packed under vacuum and stored at refrigeration temperature of 4°C for 12 days. The influence of the combined effect of spices and marination on beef stability was evaluated by monitoring pH evolution, degree of lipid oxidation and by microbiological analysis. For control samples, a mean increase of 0.47 log CFU/g of total mesophilic aerobic bacteria was observed during the 48 h of storage, but for the samples marinated with the addition of spices was observed a decrease of 0.57 log CFU/g. The growth of LAB in control samples was generally limited and did not exceed 5 log CFU/g. During storage at 4°C, marination with the addition in the base marinade (wine, honey, garlic, pepper and salt of thyme, marjoram and horseradish separately inhibited the growth of LAB while marination with the addition in the base marinade of thyme, marjoram and horseradish together resulted in significantly lower levels of LAB. All marination treatments resulted in significantly lower TBA and POV values at the end of storage compared to the control. Marination with dry red wine, lime-tree honey, thyme marjoram, garlic, and horseradish can evidently control total mesophilic aerobic bacteria, lactic acid bacteria and oxidation of beef meat.

  3. The effect of vacuum environment on creep rupture properties of Inconel 617 at 1000 deg C

    International Nuclear Information System (INIS)

    Ohnami, Masateru; Imamura, Riuzo

    1981-01-01

    The creep rupture strength of nickel-base superalloy in weakly acidic gas at high temperature above 1000 deg C lowers remarkably as compared with that in the atmosphere, and this problem is one of the important subjects in connection with the research and development of high temperature heat exchangers for multi-purpose high temperature gas-cooled reactor system being developed in Japan. In the case of Inconel 617, abnormal decarbonization phenomenon occurs in weakly acidic gas, and this is regarded as the cause of lowering the creep strength. In this study, the effects of the decarbonization in weak vacuum at 1000 deg C and the oxidation of Inconel 617 on its crack occurrence and propagation were clarified experimentally with notched plate test pieces. The material used was Inconel 617 nickel-base superalloy made by Huntington Alloys Inc. in the U.S. The creep rupture experiment was carried out with a simple tension creep tester. At the nominal stress of 3.5 kg/mm 2 , the creep rupture time in 0.3 Torr was the shortest when the grain size was 78 μm, and the creep rupture time increased as the grain size became larger. The creep rupture time in 0.3 Torr decreased to a half of that in the atmosphere. In 0.3 Torr, cracks occurred early, and propagated fast as compared with in the atmosphere. This is because the local creep velocity at the bottom of notches and in front of creep cracks is fast owing to the lack of protective oxide film. (Kako, I.)

  4. Effects of the lateral amplitude and regularity of upper body fluctuation on step time variability evaluated using return map analysis.

    Science.gov (United States)

    Chidori, Kazuhiro; Yamamoto, Yuji

    2017-01-01

    The aim of this study was to evaluate the effects of the lateral amplitude and regularity of upper body fluctuation on step time variability. Return map analysis was used to clarify the relationship between step time variability and a history of falling. Eleven healthy, community-dwelling older adults and twelve younger adults participated in the study. All of the subjects walked 25 m at a comfortable speed. Trunk acceleration was measured using triaxial accelerometers attached to the third lumbar vertebrae (L3) and the seventh cervical vertebrae (C7). The normalized average magnitude of acceleration, the coefficient of determination ($R^2$) of the return map, and the step time variabilities, were calculated. Cluster analysis using the average fluctuation and the regularity of C7 fluctuation identified four walking patterns in the mediolateral (ML) direction. The participants with higher fluctuation and lower regularity showed significantly greater step time variability compared with the others. Additionally, elderly participants who had fallen in the past year had higher amplitude and a lower regularity of fluctuation during walking. In conclusion, by focusing on the time evolution of each step, it is possible to understand the cause of stride and/or step time variability that is associated with a risk of falls.

  5. Insulation vacuum and beam vacuum overpressure release

    CERN Document Server

    Parma, V

    2009-01-01

    There is evidence that the incident of 19th September caused a high pressure build-up inside the cryostat insulation vacuum which the existing overpressure devices could not contain. As a result, high longitudinal forces acting on the insulation vacuum barriers developed and broke the floor and the floor fixations of the SSS with vacuum barriers. The consequent large longitudinal displacements of the SSS damaged chains of adjacent dipole cryo-magnets. Estimates of the helium mass flow and the pressure build- up experienced in the incident are presented together with the pressure build-up for an even more hazardous event, the Maximum Credible Incident (MCI). The strategy of limiting the maximum pressure by the installation of addition pressure relieve devices is presented and discussed. Both beam vacuum lines were ruptured during the incident in sector 3-4 giving rise to both mechanical damage and pollution of the system. The sequence, causes and effects of this damage will be briefly reviewed. We will then an...

  6. Equalizing effect of the fluctuation in areal irradiance; Chiikinai ni okeru shugo nissha no hendo yokusei koka

    Energy Technology Data Exchange (ETDEWEB)

    Minowa, J; Kurokawa, K [Tokyo University of Agriculture and Technology, Tokyo (Japan); Otani, K; Tsuda, I; Sakuta, K [Electrotechnical Laboratory, Tsukuba (Japan)

    1997-11-25

    Aggravation in electric power quality is concerned because of irregular output power caused by a large number of photovoltaic power generation systems connected with the power grids. However, averaging of the irregularity may be expected in a wide area due to time-based shift in cloud movements. In order to identify this effect, insolation data were measured in terms of planes at multiple points in the city of Tsukuba to discuss the fluctuation equalizing effect. The system is composed of nine instruments to measure insolation plane characteristics, nine terminal station units, and a base station unit. The insolation data express the horizontal plane insolation intensity at a sampling interval of one minute. Insolation fluctuation (standard deviation of insolation fluctuation components) was defined as an index of the insolation fluctuation. Based on the index, an averaging effect when the photovoltaic systems are installed in a number of locations was considered by using statistic estimation. As a result, the averaging effect was obtained even in an area with a radius of several kilometers. In addition, the measurement data revealed that there is an upper limit in the effect depending on the number of system installation. It was also made clear that the data are affected by distances to connect the photovoltaic power generation systems with each other and by climatic conditions. 3 refs., 6 figs.

  7. The effects of the vegetable prices insurance on the fluctuation of price: Based on Shanghai evidences

    Science.gov (United States)

    Qu, Chunhong; Li, Huishang; Hao, Shuai; Zhang, Xuebiao; Yang, Wei

    2017-10-01

    Taking Shanghai as an example, the influence of the vegetable price insurance on the fluctuation of prices was analyzed in the article. It was found that the sequence of seasonal fluctuations characteristics of leafy vegetable prices was changed by the vegetable cost-price insurance, the period of price fluctuation was elongated from 12-to-18 months to 37 months, and the influence of random factors on the price fluctuations was reduced in some degree. There was still great space for innovation of the vegetable prices insurance system in Shanghai. Some countermeasures would be suggested to develop the insurance system to better to play the role of insurance and promote the market running more smoothly in Shanghai such as prolonging the insurance cycle, improving the price information monitoring mechanism and innovating income insurance products and so on.

  8. Effect of spin fluctuations on the electronic structure in iron-based superconductors

    Science.gov (United States)

    Heimes, Andreas; Grein, Roland; Eschrig, Matthias

    2012-08-01

    Magnetic inelastic neutron scattering studies of iron-based superconductors reveal a strongly temperature-dependent spin-fluctuation spectrum in the normal conducting state, which develops a prominent low-energy resonance feature when entering the superconducting state. Angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling spectroscopy (STS) allow us to study the fingerprints of fluctuation modes via their interactions with electronic quasiparticles. We calculate such fingerprints in 122 iron pnictides using an experimentally motivated spin-fluctuation spectrum and make a number of predictions that can be tested in ARPES and STS experiments. This includes discussions of the quasiparticle scattering rate and the superconducting order parameter. In quantitative agreement with experiment we reproduce the quasiparticle dispersions obtained from momentum distribution curves as well as energy distribution curves. We discuss the relevance of the coupling between spin fluctuations and electronic excitations for the superconducting mechanism.

  9. Effects of lattice fluctuations on electronic transmission in metal/conjugated-oligomer/metal structures

    International Nuclear Information System (INIS)

    Yu, Z.G.; Smith, D.L.; Saxena, A.; Bishop, A.R.

    1997-01-01

    The electronic transmission across metal/conjugated-oligomer/metal structures in the presence of lattice fluctuations is studied for short oligomer chains. The lattice fluctuations are approximated by static white noise disorder. Resonant transmission occurs when the energy of an incoming electron coincides with a discrete electronic level of the oligomer. The corresponding transmission peak diminishes in intensity with increasing disorder strength. Because of disorder there is an enhancement of the electronic transmission for energies that lie within the electronic gap of the oligomer. If fluctuations are sufficiently strong, a transmission peak within the gap is found at the midgap energy E=0 for degenerate conjugated oligomers (e.g., trans-polyacetylene) and E≠0 for AB-type degenerate oligomers. These results can be interpreted in terms of soliton-antisoliton states created by lattice fluctuations. copyright 1997 The American Physical Society

  10. Effects of dust-charge fluctuations on the potential of an array of projectiles in a partially ionized dusty plasma

    International Nuclear Information System (INIS)

    Ali, S.; Nasim, M.H.; Murtaza, G.

    2003-01-01

    The expressions for the Debye and the wake potential are derived by incorporating dust-charge fluctuations of a single projectile, as well as of an array of dust grain projectiles, propagating through a partially ionized dusty plasma with a constant velocity. Numerically, the effects of the dust-charge fluctuations and the dust-neutral collisions on the electrostatic potential for a single, three, six and ten projectiles are examined. The dust-charge relaxation rate modifies the shape of the Debye as well as the wake potential. For smaller values of the relaxation rates a potential well is formed instead of Debye potential

  11. Effects of high frequency fluctuations on DNS of turbulent open-channel flow with high Pr passive scalar transport

    International Nuclear Information System (INIS)

    Yamamoto, Yoshinobu; Kunugi, Tomoaki; Serizawa, Akimi

    2002-01-01

    In this study, investigation on effects of high frequency fluctuations on DNS of turbulent open-channel flows with high Pr passive scalar transport was conducted. As the results, although significant differences of energy spectra behaviors in temperature fields, are caused at high wave number region where insignificant area for velocity components, large difference dose not caused in mean and statistic behaviors in temperature component. But, if the buoyancy were considered, this temperature high-frequency fluctuations would be greatly changed mean and statistics behaviors from the difference of the accuracy and resolution at high wave number region. (author)

  12. Fluctuation analysis

    International Nuclear Information System (INIS)

    Clarke, J.

    1980-01-01

    This paper briefly reviews sources of noise in Josephson junctions, and the limits they impose on the sensitivity of dc and rf SQUIDS. The results are strictly valid only for a resistively shunted junction (RSJ) with zero capacitance, but should be applicable to point contact junctions and microbridges in so far as these devices can be approximated by the RSJ model. Fluctuations arising from Nyquist noise in the resistive shunt of a single junction are discussed in the limit eI/sub o/R/k/sub B/T << 1 in which a classical treatment is appropriate, and then extend the treatment to the limit eI/sub o/R/k/sub B/T greater than or equal to 1 in which quantum effects become important. The Nyquist limit theory is used to calculate the noise in a dc SQUID, and the results are compared with a number of practical devices. The quantum limit is briefly considered. Results for the predicted sensitivity of rf SQUIDS are presented, and also compared with a number of practical devices. Finally, the importance of l/f noise (f is the frequency) in limiting the low frequency performance of SQUIDS is discussed

  13. The Effect of Climate, Environment and Man on Variations in Wildlife Population Fluctuations in Greenland Over 200 Years

    DEFF Research Database (Denmark)

    Moshøj, Charlotte Margaret

    The Effect of Climate, Environment and Man on Variations in Wildlife Population Fluctuations in Greenland Over 200 Years Moshøj, Charlotte The underlying factors of species fluctuating population dynamics has been the dominant focus of attention in population ecology throughout much of this century...... passed on from Inuit elders all document that the presence of wildlife species and their population sizes have undergone pronounced fluctuations throughout recordable historical time. The most detailed accounts are found for the species that were harvested or had economical value. While several recent...... data, environmental factors and temporal variations in social and demographic parameters in the existing society. The results of this study model future predictions of wildlife populations under changing climate variables and human hunting pressure. View Presentation....

  14. Pharmacologically Induced Sex Hormone Fluctuation Effects on Resting-State Functional Connectivity in a Risk Model for Depression

    DEFF Research Database (Denmark)

    Fisher, Patrick MacDonald; Larsen, Camilla Borgsted; Beliveau, Vincent

    2017-01-01

    Women are at relatively greater lifetime risk for depression than men. This elevated risk in women is partly due to heightened risk during time periods characterized by marked fluctuations in sex hormones, including postpartum and perimenopausal periods. How sex hormone fluctuations contribute...... to heightened risk is not fully understood but may involve intrinsic functional connectivity. We induced a biphasic ovarian sex hormone fluctuation using the gonadotropin-releasing hormone agonist (GnRHa) goserelin to determine, with a randomized placebo-controlled design, intervention effects on or Gn....... Considering the GnRHa group only, the emergence of depressive symptoms following intervention was positively associated with amygdala-right temporal cortex and negatively associated with hippocampus-cingulate rs-FC. A test for mediation suggested that rs-FC changes in these networks marginally mediated...

  15. The Effect of Thermal Fluctuation on the Receptor-Mediated Adhesion of a Cell Membrane to an Elastic Substrate

    Directory of Open Access Journals (Sweden)

    Bahador Marzban

    2017-04-01

    Full Text Available Mechanics of the bilayer membrane play an important role in many biological and bioengineering problems such as cell–substrate and cell–nanomaterial interactions. In this work, we study the effect of thermal fluctuation and the substrate elasticity on the cell membrane–substrate adhesion. We model the adhesion of a fluctuating membrane on an elastic substrate as a two-step reaction comprised of the out-of-plane membrane fluctuation and the receptor–ligand binding. The equilibrium closed bond ratio as a function of substrate rigidity was computed by developing a coupled Fourier space Brownian dynamics and Monte Carlo method. The simulation results show that there exists a crossover value of the substrate rigidity at which the closed bond ratio is maximal.

  16. Effects of fluctuating temperature and food availability on reproduction and lifespan

    OpenAIRE

    Schwartz, Tonia S.; Pearson, Phillip; Dawson, John; Allison, David B.; Gohlke, Julia M.

    2016-01-01

    Experimental studies on energetics and aging often remove two major factors that in part regulate the energy budget in a normal healthy individual: reproduction and fluctuating environmental conditions that challenge homeostasis. Here we use the cyclical parthenogenetic Daphnia pulex to evaluate the role of a fluctuating thermal environment on both reproduction and lifespan across six food concentrations. We test the hypotheses that (1) caloric restriction extends lifespan; (2) maximal reprod...

  17. PDX vacuum vessel stress analysis

    International Nuclear Information System (INIS)

    Nikodem, Z.D.

    1975-01-01

    A stress analysis of PDX vacuum vessel is described and the summary of results is presented. The vacuum vessel is treated as a toroidal shell of revolution subjected to an internal vacuum. The critical buckling pressure is calculated. The effects of the geometrical discontinuity at the juncture of toroidal shell head and cylindrical outside wall, and the concavity of the cylindrical wall are examined. An effect of the poloidal field coil supports and the vessel outside supports on the stress distribution in the vacuum vessel is determined. A method evaluating the influence of circular ports in the vessel wall on the stress level in the vessel is outlined

  18. Effect of quantum fluctuations of synchrotron radiation on the dynamics of particles in high-energy microtrons

    International Nuclear Information System (INIS)

    Bessonov, E.G.

    1987-01-01

    Crosbie has demonstrated numerically that the effect of quantum fluctuation of synchrotron radiation on the beam emittance becomes significant in microtrons for an energy of more than 1 GeV. In this paper the authors give analytic expressions that describe this phenomenon and analyze these expressions

  19. The ecological effects of water level fluctuation and phosphate enrichment in mesotrophic peatlands are strongly mediated by soil chemistry

    NARCIS (Netherlands)

    Mettrop, I.S.; Rutte, M.D.; Kooijman, A.M.; Lamers, L.P.M.

    2015-01-01

    Since the re-establishment of a more natural water regime is considered by water management in wetlands with artificially stable water levels, the biogeochemical and ecological effects of water level fluctuation with different nutrient loads should be investigated. This is particularly important for

  20. An effective vacuum assisted extraction method for the optimization of labdane diterpenoids from Andrographis paniculata by response surface methodology.

    Science.gov (United States)

    Wang, Ya-Qi; Wu, Zhen-Feng; Ke, Gang; Yang, Ming

    2014-12-31

    An effective vacuum assisted extraction (VAE) technique was proposed for the first time and applied to extract bioactive components from Andrographis paniculata. The process was carefully optimized by response surface methodology (RSM). Under the optimized experimental conditions, the best results were obtained using a boiling temperature of 65 °C, 50% ethanol concentration, 16 min of extraction time, one extraction cycles and a 12:1 liquid-solid ratio. Compared with conventional ultrasonic assisted extraction and heat reflux extraction, the VAE technique gave shorter extraction times and remarkable higher extraction efficiency, which indicated that a certain degree of vacuum gave the solvent a better penetration of the solvent into the pores and between the matrix particles, and enhanced the process of mass transfer. The present results demonstrated that VAE is an efficient, simple and fast method for extracting bioactive components from A. paniculata, which shows great potential for becoming an alternative technique for industrial scale-up applications.

  1. An Effective Vacuum Assisted Extraction Method for the Optimization of Labdane Diterpenoids from Andrographis paniculata by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Ya-Qi Wang

    2014-12-01

    Full Text Available An effective vacuum assisted extraction (VAE technique was proposed for the first time and applied to extract bioactive components from Andrographis paniculata. The process was carefully optimized by response surface methodology (RSM. Under the optimized experimental conditions, the best results were obtained using a boiling temperature of 65 °C, 50% ethanol concentration, 16 min of extraction time, one extraction cycles and a 12:1 liquid-solid ratio. Compared with conventional ultrasonic assisted extraction and heat reflux extraction, the VAE technique gave shorter extraction times and remarkable higher extraction efficiency, which indicated that a certain degree of vacuum gave the solvent a better penetration of the solvent into the pores and between the matrix particles, and enhanced the process of mass transfer. The present results demonstrated that VAE is an efficient, simple and fast method for extracting bioactive components from A. paniculata, which shows great potential for becoming an alternative technique for industrial scale-up applications.

  2. Vacuum space charge effects in sub-picosecond soft X-ray photoemission on a molecular adsorbate layer.

    Science.gov (United States)

    Dell'Angela, M; Anniyev, T; Beye, M; Coffee, R; Föhlisch, A; Gladh, J; Kaya, S; Katayama, T; Krupin, O; Nilsson, A; Nordlund, D; Schlotter, W F; Sellberg, J A; Sorgenfrei, F; Turner, J J; Öström, H; Ogasawara, H; Wolf, M; Wurth, W

    2015-03-01

    Vacuum space charge induced kinetic energy shifts of O 1s and Ru 3d core levels in femtosecond soft X-ray photoemission spectra (PES) have been studied at a free electron laser (FEL) for an oxygen layer on Ru(0001). We fully reproduced the measurements by simulating the in-vacuum expansion of the photoelectrons and demonstrate the space charge contribution of the high-order harmonics in the FEL beam. Employing the same analysis for 400 nm pump-X-ray probe PES, we can disentangle the delay dependent Ru 3d energy shifts into effects induced by space charge and by lattice heating from the femtosecond pump pulse.

  3. Proton flux effects and prediction on the free radicals behavior of polyimide in vacuum using EPR measurements in ambient

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Chengyue [Physics Department, Harbin Institute of Technology, Harbin 150001 (China); National Key Lab of Materials Behaviors and Evaluation Technology in Space Environments, Harbin Institute of Technology, Harbin 150001 (China); Wu, Yiyong, E-mail: wuyiyong@hit.edu.cn [National Key Lab of Materials Behaviors and Evaluation Technology in Space Environments, Harbin Institute of Technology, Harbin 150001 (China); Xiao, Jingdong [National Key Lab of Materials Behaviors and Evaluation Technology in Space Environments, Harbin Institute of Technology, Harbin 150001 (China); Yu, Sui [Physics Department, Harbin Institute of Technology, Harbin 150001 (China); Yi, Zhong; Shen, Zicai [Chinese Academy of Sciences, Beijing 100029 (China); Wang, Li [Qian Xuesen Laboratory of Space Technology, Beijing 100029 (China); Wang, Yi [Lanzhou Institute of Physics, CAST, Lanzhou 730000 (China)

    2017-04-15

    Irradiation flux is an important parameter to the material irradiation damage investigation, for space material irradiation damage evaluation and the accelerated ground-based test, the irradiation flux effects cannot be ignored. In this paper, the polyimide was set as the research object, the irradiation flux effect and mechanism are investigated by the means of electron paramagnetic resonance test, and based on the free radical dynamic analysis, the dynamics mode of free radical population in vacumm can be established as a function of irradiation time (or proton irradiation flux). The results show that the free radical anneal process in vacuum follows the exponential mode, and the characteristic time constant τ{sub radical-vacuum} is about 1.9 h. Furthermore, a simplified method is proposed with the investigation of the free radical behavior of the irradiated surface modification polyimide (TiO{sub 2}/PI), and the characteristic time constant τ{sub bulk} is 1.9 h, which is almost the same to the value of τ{sub radical-vacuum}.

  4. Quantum fluctuations and inflation

    International Nuclear Information System (INIS)

    Bardeen, J.M.; Bublik, G.J.

    1986-05-01

    We study the effect of quantum fluctuations on the roll-down rate of the inflation field in a semiclassical approximation; this is done by treating the inflation field as a classical random field. The quantum fluctuations are simulated by a noise term in the equation of motion. We consider two different inflationary scenarios (new and chaotic inflation) and find that the roll-down rate of the median value of the inflation field is increased by the quantum fluctuations. Non-linear effects may become important in the later stages of the inflationary regime. 8 refs., 2 figs

  5. Quantum fluctuations and inflation

    International Nuclear Information System (INIS)

    Bardeen, J.M.; Bublik, G.J.

    1987-01-01

    The authors study the effect of quantum fluctuations on the roll-down rate of the inflation field in a semiclassical approximation; this is done by treating the inflation field as a classical random field. The quantum fluctuations are simulated by a noise term in the equation of motion. Two different inflationary scenarios (new and chaotic inflation) are considered and it is found that the roll-down rate of the median value of the inflation field is increased by the quantum fluctuations. Non-linear effects may become important in the later stages of the inflationary regime. (author)

  6. Effects of Pleistocene sea-level fluctuations on mangrove population dynamics: a lesson from Sonneratia alba.

    Science.gov (United States)

    Yang, Yuchen; Li, Jianfang; Yang, Shuhuan; Li, Xinnian; Fang, Lu; Zhong, Cairong; Duke, Norman C; Zhou, Renchao; Shi, Suhua

    2017-01-18

    A large-scale systematical investigation of the influence of Pleistocene climate oscillation on mangrove population dynamics could enrich our knowledge about the evolutionary history during times of historical climate change, which in turn may provide important information for their conservation. In this study, phylogeography of a mangrove tree Sonneratia alba was studied by sequencing three chloroplast fragments and seven nuclear genes. A low level of genetic diversity at the population level was detected across its range, especially at the range margins, which was mainly attributed to the steep sea-level drop and associated climate fluctuations during the Pleistocene glacial periods. Extremely small effective population size (Ne) was inferred in populations from both eastern and western Malay Peninsula (44 and 396, respectively), mirroring the fragility of mangrove plants and their paucity of robustness against future climate perturbations and human activity. Two major genetic lineages of high divergence were identified in the two mangrove biodiversity centres: the Indo-Malesia and Australasia regions. The estimated splitting time between these two lineages was 3.153 million year ago (MYA), suggesting a role for pre-Pleistocene events in shaping the major diversity patterns of mangrove species. Within the Indo-Malesia region, a subdivision was implicated between the South China Sea (SCS) and the remaining area with a divergence time of 1.874 MYA, corresponding to glacial vicariance when the emerged Sunda Shelf halted genetic exchange between the western and eastern coasts of the Malay Peninsula during Pleistocene sea-level drops. Notably, genetic admixture was observed in populations at the boundary regions, especially in the two populations near the Malacca Strait, indicating secondary contact between divergent lineages during interglacial periods. These interregional genetic exchanges provided ample opportunity for the re-use of standing genetic variation

  7. Effect of magnetic configuration on density fluctuation and particle transport in LHD

    International Nuclear Information System (INIS)

    Tanaka, K.; Michael, C.; Yamagishi, O.; Ida, K.; Yamada, H.; Yoshinuma, M.; Yokoyama, M.; Miyazawa, J.; Morita, S.; Kawahata, K.; Tokzawa, T.; Shoji, M.; Vyacheslavov, L.N.; Sanin, A.L.

    2005-01-01

    The study of fluctuations and particle transport is important issue in heliotron and stellarator devices as well as in tokamaks. A two dimensional phase contrast interferometer (2D PCI) was developed to investigate fluctuation characteristics, which play role in confinement. The current 2D PCI can detect fluctuations for which -1 0.3 -1 and 5< f<500kHz. With the use of magnetic shear and the 2D detector, the spatial resolution around 20% of averaged minor radius is possible presently. The strongest fluctuations are localized in the plasma edge, where density gradients are negative, but fluctuations also exist in the positive density gradient region of the hollow density profile. The phase velocity of fluctuations in the positive gradient region is close to plasma ErxBt rotation. On the other hand, fluctuations in the negative density gradient region propagate in the ion diamagnetic direction in the plasma frame and do not follow ErxBt rotation. This suggests there is a different nature of the fluctuations in the positive and negative density gradient regions. A particle transport was studied by means of density modulation experiments. The systematic study was done at Rax=3.6m, which is so-called standard configuration. The density profiles vary from peaked to hollow with increasing heating power. It was also found that particle diffusion and convection are functions of electron temperature and its gradient respectively. The magnetic configuration is another parameter, which characterizes particle confinement. At more outward shifted configurations, helical ripple becomes larger and the ergodic region becomes thicker, then neoclassical transport becomes larger. However estimated diffusion coefficients are still around one order of magnitude larger than neoclassical values in edge region, where ρ = 0.7 ∼ 1.0 and they are larger at more outward configurations. At the same time the convection velocity is found to be comparable with neoclassical prediction at Rax=3

  8. Synergistic effects of seasonal rainfall, parasites and demography on fluctuations in springbok body condition

    Science.gov (United States)

    Turner, Wendy C.; Versfeld, Wilferd D.; Kilian, J. Werner; Getz, Wayne M.

    2011-01-01

    Summary 1. Seasonality of rainfall can exert a strong influence on animal condition and on host-parasite interactions. The body condition of ruminants fluctuates seasonally in response to changes in energy requirements, foraging patterns and resource availability, and seasonal variation in parasite infections may further alter ruminant body condition. 2. This study disentangles effects of rainfall and gastrointestinal parasite infections on springbok (Antidorcas marsupialis) body condition and determines how these factors vary among demographic groups. 3. Using data from four years and three study areas, we investigated i) the influence of rainfall variation, demographic factors and parasite interactions on parasite prevalence or infection intensity, ii) whether parasitism or rainfall is a more important predictor of springbok body condition and iii) how parasitism and condition vary among study areas along a rainfall gradient. 4. We found that increased parasite intensity is associated with reduced body condition only for adult females. For all other demographic groups, body condition was significantly related to prior rainfall and not to parasitism. Rainfall lagged by two months had a positive effect on body condition. 5. Adult females showed evidence of a “periparturient rise” in parasite intensity, and had higher parasite intensity and lower body condition than adult males after parturition and during early lactation. After juveniles were weaned, adult females had lower parasite intensity than adult males. Sex differences in parasitism and condition may be due to differences between adult females and males in the seasonal timing of reproductive effort and its effects on host immunity, as well as documented sex differences in vulnerability to predation. 6. Our results highlight that parasites and the environment can synergistically affect host populations, but that these interactions might be masked by their interwoven relationships, their differential

  9. Preheat effect on titanium plate fabricated by sputter-free selective laser melting in vacuum

    Science.gov (United States)

    Sato, Yuji; Tsukamoto, Masahiro; Shobu, Takahisa; Yamashita, Yorihiro; Yamagata, Shuto; Nishi, Takaya; Higashino, Ritsuko; Ohkubo, Tomomasa; Nakano, Hitoshi; Abe, Nobuyuki

    2018-04-01

    The dynamics of titanium (Ti) melted by laser irradiation was investigated in a synchrotron radiation experiment. As an indicator of wettability, the contact angle between a selective laser melting (SLM) baseplate and the molten Ti was measured by synchrotron X-rays at 30 keV during laser irradiation. As the baseplate temperature increased, the contact angle decreased, down to 28° at a baseplate temperature of 500 °C. Based on this result, the influence of wettability of a Ti plate fabricated by SLM in a vacuum was investigated. It was revealed that the improvement of wettability by preheating suppressed sputtering generation, and a surface having a small surface roughness was fabricated by SLM in a vacuum.

  10. Ion effects in the SLC electron damping ring under exceptionally poor vacuum conditions

    International Nuclear Information System (INIS)

    Zimmermann, F.; Krejcik, P.; Minty, M.; Pritzkau, D.; Raubenheimer, T.; Ross, M.; Woodley, M.

    1997-10-01

    In 1996, due to a catastrophic kicker chamber failure in the SLC electron damping ring, the ring vacuum system was contamianted for several months. During this time, the vertical emittance of the beam extracted from the ring was increased by a large factor (4--20). The emittance slowly decreased as the vacuum pressure gradually improved. At the same time, an intermittent vertical instability was observed. Both the emittance blow-up and the instability behavior depended strongly on beam current, ring pressure, number of bunches in the ring (1 or 2), duty cycle, store time and betatron tunes. In this report, the authors describe the observations, and compare them with predictions from classical ion-trapping and ion-instability theories

  11. Effect of vacuum oxy-nitrocarburizing on the microstructure of tool steels: an experimental and modeling study

    Directory of Open Access Journals (Sweden)

    Nikolova Maria

    2017-01-01

    Full Text Available The thermochemical treatments of tool steels improve the performance of the components with respect to surface hardness, wear and tribological performance as well as corrosion resistance. Compared to the conventional gas ferritic nitrocarburizing process, the original vacuum oxy-nitrocarburizing is a time-, cost-effective and environmentally-friendly gas process. Because of the oxidizing nature of the gas atmosphere, there is no need to perform subsequent post-oxidation.In this study, a vacuum oxynitrocarburizing process was carried out onto four tool steels (AISI H10, H11, H21 and D2 at 570 °C, after hardening and single tempering. The structural analysis of the compound and diffusion layers was performed by optical and electron microscopy, X-ray diffraction and glow discharge optical emission spectrometry (GDOES methods. A largely monophase ε- layer is formed with a carbon accumulation at the substrate adjacent area. The overlaying oxides adjacent to the ε-carbonitride phase contained Fe3O4 (magnetite as a main constituent. A thermodynamic modelling approach was also performed to understand and optimize the process. The “Equilib module” of FactSage software which uses Gibbs energy minimization method, was used to estimate the possible products during vacuum oxynitrocarburising process.

  12. The effect of grinding at various vacuum levels on the color, phenolics, and antioxidant properties of apple.

    Science.gov (United States)

    Kim, Ah-Na; Kim, Hyun-Jin; Kerr, William L; Choi, Sung-Gil

    2017-02-01

    The purpose of this study was to evaluate the effect of grinding at different vacuum levels (2.67, 6.67, 13.33, 19.99, and 101.33kPa) on key quality factors of apple. In the control apple, ground at atmospheric pressure of 101.33kPa, the antioxidant activities rapidly decreased within the first 30min, then plateaued thereafter, while enzymatic browning increased. When apples were ground and held under vacuum, changes in color and antioxidant activity were much less, and the least change was measured in samples prepared at the lowest pressure. Model fitting of the data showed that antioxidant activity decreased as a function of the logarithm of the absolute pressure. The results from analysis for key phenolic compounds including chlorogenic acid, procyanidin B2, and epicatechin indicated that these compounds were least changed at vacuum grinding at 2.67kPa, compared to atmospheric grinding. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Eddy Current Effect of the BNL-AGS Vacuum Chamber on the Optics of the BNL-AGS Synchrotron

    International Nuclear Information System (INIS)

    Tsoupas, N.; Ahrens, L.; Brown, K. A.; Glenn, J. W.; Gardner, K.

    1999-01-01

    During the acceleration cycle of the AGS synchrotron, eddy currents are generated within the walls of the vacuum chambers of the AGS main magnets. The vacuum chambers have elliptical cross section, are made of inconel material with a wall thickness of 2 mm and are placed within the gap of the combined-function main magnets of the AGS synchrotron. The generation of eddy currents in the walls of the vacuum chambers, creates various magnetic multipoles, which affect the optics of the AGS machine. In this report these magnetic multipoles are calculated for various time interval starting at the acceleration cycle, where the magnetic field of the main magnet is ∼0.1 T, and ending before the beam extraction process, where the magnetic field of the main magnet is almost constant at ∼ 1.1 T. The calculations show that the magnetic multipoles generated by the eddy-currents affect the optics of the AGS synchrotron during the acceleration cycle and in particular at low magnetic fields of the main magnet. Their effect is too weak to affect the optics of the AGS machine during beam extraction at the nominal energies

  14. Effect of vacuum impregnation temperature on the mechanical properties and osmotic dehydration parameters of apples

    Directory of Open Access Journals (Sweden)

    Sabrina Silva Paes

    2008-08-01

    Full Text Available The effect of sucrose solution temperature on the mechanical properties, water loss (WL, solids gain (SG and weight reduction (WR of apples (Fuji var. treated by vacuum impregnation was studied. Temperatures were varied from 10 to 50 ºC, using a sucrose solution of 50 ºBrix. The mechanical properties were studied throughout a stress relaxation test. The results showed that the SG varied between 10.57 and 14.29 % and the WL varied between 10.55 and 14.48 %. The treated fruit soluble solids increased with the temperature probably due to the lower viscosity of the solution. The maximum stress was highest at 10 ºC, decreasing at higher temperatures, probably due the softening of the structure.A impregnação a vácuo (VI de alimentos é realizada pela aplicação de vácuo em um tanque contendo o produto imerso em uma solução, seguida da recuperação da pressão atmosférica. Neste trabalho, estudou-se o efeito da temperatura da solução de sacarose nas propriedades mecânicas das amostras e na perda de água (WL, ganho de sólidos (SG e redução de peso (WR. A faixa de temperaturas estudada foi de 10 a 50 ºC, usando uma solução de sacarose com 50 ºBrix. As propriedades mecânicas das amostras foram estudadas através de ensaios mecânicos de deformação-relaxação. O SG variou entre 10.57 e 14.29 %, enquanto WL variou entre 10.55 e 14.48 %. O teor de sólidos das frutas tratadas aumentou com a temperatura, provavelmente devido à diminuição da viscosidade da solução. A tensão máxima foi maior a 10 ºC, diminuindo com a temperatura, devido ao amolecimento da estrutura.

  15. Effects of vacuum and ageing on Zr4/Cr3 based conversion coatings on aluminium alloys

    Science.gov (United States)

    Thirupathi, Kalaivanan; Bárczy, Pál; Vad, Kálmán; Csik, Attila; Somosvári, Béla Márton

    2018-05-01

    In this study, we investigate the impact of ageing and high vacuum on existing environmentally friendly Zr4/Cr3-based conversion coatings. The freshly formed coating undergoes several changes during ageing and exposure to high vacuum. Based on the present data, we propose that the coating formed over AA6082 and AA7075 alloys is sol-gel in nature, confirmed by secondary neutral mass spectroscopy (SNMS) using the depth profiling technique. Our findings reveal that there are elemental level changes that result in shrinkage of the coating. Most Zr ions in the coating are in the solute form, with lesser number of Cr and Al ions that disappear under high vacuum over a certain period of time. The remaining Cr, Zr and O atoms exist in a gelatinous state. During ageing, there is a continuous transition of ions from solute to gelatinous state. In addition, the deposition of coating ions is directly influenced by the substrates and their constituents. The extent of dissolution of aluminium in the conversion bath determines both Zr and Cr ion deposition. For a highly alloyed metal like AA7075, the dissolution rate is disturbed by copper and zinc.

  16. Surface and finite size effect on fluctuations dynamics in nanoparticles with long-range order

    Science.gov (United States)

    Morozovska, A. N.; Eliseev, E. A.

    2010-02-01

    The influence of surface and finite size on the dynamics of the order parameter fluctuations and critical phenomena in the three-dimensional (3D)-confined systems with long-range order was not considered theoretically. In this paper, we study the influence of surface and finite size on the dynamics of the order parameter fluctuations in the particles of arbitrary shape. We consider concrete examples of the spherical and cylindrical ferroic nanoparticles within Landau-Ginzburg-Devonshire phenomenological approach. Allowing for the strong surface energy contribution in micro and nanoparticles, the analytical expressions derived for the Ornstein-Zernike correlator of the long-range order parameter spatial-temporal fluctuations, dynamic generalized susceptibility, relaxation times, and correlation radii discrete spectra are different from those known for bulk systems. Obtained analytical expressions for the correlation function of the order parameter spatial-temporal fluctuations in micro and nanosized systems can be useful for the quantitative analysis of the dynamical structural factors determined from magnetic resonance diffraction and scattering spectra. Besides the practical importance of the correlation function for the analysis of the experimental data, derived expressions for the fluctuations strength determine the fundamental limits of phenomenological theories applicability for 3D-confined systems.

  17. Incidence Angle Effect of Energetic Carbon Ions on Deposition Rate, Topography, and Structure of Ultrathin Amorphous Carbon Films Deposited by Filtered Cathodic Vacuum Arc

    KAUST Repository

    Wang, N.; Komvopoulos, K.

    2012-01-01

    The effect of the incidence angle of energetic carbon ions on the thickness, topography, and structure of ultrathin amorphous carbon (a-C) films synthesized by filtered cathodic vacuum arc (FCVA) was examined in the context of numerical

  18. Simulated Seasonal Photoperiods and Fluctuating Temperatures Have Limited Effects on Blood Feeding and Life History in Aedes triseriatus (Diptera: Culicidae).

    Science.gov (United States)

    Westby, K M; Juliano, S A

    2015-09-01

    Biotic and abiotic factors change seasonally and impact life history in temperate-zone ectotherms. Temperature and photoperiod are factors that change in predictable ways. Most studies testing for effects of temperature on vectors use constant temperatures and ignore potential correlated effects of photoperiod. In two experiments, we tested for effects of larval rearing environments creating ecologically relevant temperatures and photoperiods simulating early and late season conditions (June and August), or constant temperatures (cool and warm) with the June or August photoperiods, respectively. We determined effects on survivorship, development, size, and a composite performance index in a temperate-zone population of Aedes triseriatus (Say). We followed cohorts of resulting females, all held under the same environmental conditions, to assess carry-over effects of rearing conditions for larvae on longevity, blood feeding, and egg production. Larval survivorship was affected by treatment in one experiment. Development time was greater in the June and cool treatments, but the constant and fluctuating temperatures did not differ. Significantly larger mosquitoes were produced in fluctuating versus constant temperature treatments. There were no significant treatment effects on the composite performance index. Adult female longevity was lower after rearing at constant versus fluctuating temperature, but there was no difference between June and August, nor did size affect longevity. There was no effect of treatments on blood feeding and a limited effect on egg production. We conclude that seasonal temperatures and photoperiods during development have limited effects on this population of A. triseriatus and find little evidence of strong effects of fluctuating versus constant temperatures. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Manipulating lightcone fluctuations in an analogue cosmic string

    Directory of Open Access Journals (Sweden)

    Jiawei Hu

    2018-02-01

    Full Text Available We study the flight time fluctuations in an anisotropic medium inspired by a cosmic string with an effective fluctuating refractive index caused by fluctuating vacuum electric fields, which are analogous to the lightcone fluctuations due to fluctuating spacetime metric when gravity is quantized. The medium can be realized as a metamaterial that mimics a cosmic string in the sense of transformation optics. For a probe light close to the analogue string, the flight time variance is ν times that in a normal homogeneous and isotropic medium, where ν is a parameter characterizing the deficit angle of the spacetime of a cosmic string. The parameter ν, which is always greater than unity for a real cosmic string, is determined by the dielectric properties of the metamaterial for an analogue string. Therefore, the flight time fluctuations of a probe light can be manipulated by changing the electric permittivity and magnetic permeability of the analogue medium. We argue that it seems possible to fabricate a metamaterial that mimics a cosmic string with a large ν in laboratory so that a currently observable flight time variance might be achieved.

  20. Manipulating lightcone fluctuations in an analogue cosmic string

    Science.gov (United States)

    Hu, Jiawei; Yu, Hongwei

    2018-02-01

    We study the flight time fluctuations in an anisotropic medium inspired by a cosmic string with an effective fluctuating refractive index caused by fluctuating vacuum electric fields, which are analogous to the lightcone fluctuations due to fluctuating spacetime metric when gravity is quantized. The medium can be realized as a metamaterial that mimics a cosmic string in the sense of transformation optics. For a probe light close to the analogue string, the flight time variance is ν times that in a normal homogeneous and isotropic medium, where ν is a parameter characterizing the deficit angle of the spacetime of a cosmic string. The parameter ν, which is always greater than unity for a real cosmic string, is determined by the dielectric properties of the metamaterial for an analogue string. Therefore, the flight time fluctuations of a probe light can be manipulated by changing the electric permittivity and magnetic permeability of the analogue medium. We argue that it seems possible to fabricate a metamaterial that mimics a cosmic string with a large ν in laboratory so that a currently observable flight time variance might be achieved.

  1. Effects of q-profile structure on turbulence spreading: A fluctuation intensity transport analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yi, S.; Kwon, J. M. [National Fusion Research Institute, Eoeun-dong, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Diamond, P. H. [National Fusion Research Institute, Eoeun-dong, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Center for Astrophysics and Space Sciences and Department of Physics, University of California San Diego, La Jolla, California 92093-0429 (United States); Hahm, T. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2014-09-15

    This paper studies effects of q-profile structure on turbulence spreading. It reports results of numerical experiments using global gyrokinetic simulations. We examine propagation of turbulence, triggered by an identical linear instability in a source region, into an adjacent, linearly stable region with variable q-profile. The numerical experiments are designed so as to separate the physics of turbulence spreading from that of linear stability. The strength of turbulence spreading is measured by the penetration depth of turbulence. Dynamics of spreading are elucidated by fluctuation intensity balance analysis, using a model intensity evolution equation which retains nonlinear diffusion and damping, and linear growth. It is found that turbulence spreading is strongly affected by magnetic shear s, but is hardly altered by the safety factor q itself. There is an optimal range of modest magnetic shear which maximizes turbulence spreading. For high to modest shear values, the spreading is enhanced by the increase of the mode correlation length with decreasing magnetic shear. However, the efficiency of spreading drops for sufficiently low magnetic shear even though the mode correlation length is comparable to that for the case of optimal magnetic shear. The reduction of spreading is attributed to the increase in time required for the requisite nonlinear mode-mode interactions. The effect of increased interaction time dominates that of increased mode correlation length. Our findings of the reduction of spreading and the increase in interaction time at weak magnetic shear are consistent with the well-known benefit of weak or reversed magnetic shear for core confinement enhancement. Weak shear is shown to promote locality, as well as stability.

  2. Radon entry into buildings: Effects of atmospheric pressure fluctuations and building structural factors

    International Nuclear Information System (INIS)

    Robinson, A.L.

    1996-05-01

    An improved understanding of the factors that control radon entry into buildings is needed in order to reduce the public health risks caused by exposure to indoor radon. This dissertation examines three issues associated with radon entry into buildings: (1) the influence of a subslab gravel layer and the size of the openings between the soil and the building interior on radon entry; (2) the effect of atmospheric pressure fluctuations on radon entry; and (3) the development and validation of mathematical models which simulate radon and soil-gas entry into houses. Experiments were conducted using two experimental basements to examine the influence of a subslab gravel layer on advective radon entry driven by steady indoor-outdoor pressure differences. These basement structures are identical except that in one the floor slab lies directly on native soil whereas in the other the slab lies on a high-permeability gravel layer. The measurements indicate that a high permeability subslab gravel layer increases the advective radon entry rate into the structure by as much as a factor of 30. The magnitude of the enhancement caused by the subslab gravel layer depends on the area of the openings in the structure floor; the smaller the area of these openings the larger the enhancement in the radon entry rate caused by the subslab gravel layer. A three-dimensional, finite-difference model correctly predicts the effect of a subslab gravel layer and open area configuration on advective radon entry driven by steady indoor-outdoor pressure differences; however, the model underpredicts the absolute entry rate into each structure by a factor of 1.5

  3. Radon entry into buildings: Effects of atmospheric pressure fluctuations and building structural factors

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Allen Lantham [Univ. of California, Berkeley, CA (United States). Dept. of Mechanical Engineering

    1996-05-01

    An improved understanding of the factors that control radon entry into buildings is needed in order to reduce the public health risks caused by exposure to indoor radon. This dissertation examines three issues associated with radon entry into buildings: (1) the influence of a subslab gravel layer and the size of the openings between the soil and the building interior on radon entry; (2) the effect of atmospheric pressure fluctuations on radon entry; and (3) the development and validation of mathematical models which simulate radon and soil-gas entry into houses. Experiments were conducted using two experimental basements to examine the influence of a subslab gravel layer on advective radon entry driven by steady indoor-outdoor pressure differences. These basement structures are identical except that in one the floor slab lies directly on native soil whereas in the other the slab lies on a high-permeability gravel layer. The measurements indicate that a high permeability subslab gravel layer increases the advective radon entry rate into the structure by as much as a factor of 30. The magnitude of the enhancement caused by the subslab gravel layer depends on the area of the openings in the structure floor; the smaller the area of these openings the larger the enhancement in the radon entry rate caused by the subslab gravel layer. A three-dimensional, finite-difference model correctly predicts the effect of a subslab gravel layer and open area configuration on advective radon entry driven by steady indoor-outdoor pressure differences; however, the model underpredicts the absolute entry rate into each structure by a factor of 1.5.

  4. Lithium line radiation in turbulent edge plasmas: Effects of low and high frequency temperature fluctuations

    Science.gov (United States)

    Rosato, J.; Capes, H.; Catoire, F.; Kadomtsev, M. B.; Levashova, M. G.; Lisitsa, V. S.; Marandet, Y.; Rosmej, F. B.; Stamm, R.

    2011-08-01

    In lithium-wall-conditioned tokamaks, the line radiation due to the intrinsic impurities (Li/Li+/Li++) plays a significant role on the power balance. Calculations of the radiation losses are usually performed using a stationary collisional-radiative model, assuming constant values for the plasma parameters (Ne, Te,…). Such an approach is not suitable for turbulent plasmas where the various parameters are time-dependent. This is critical especially for the edge region, where the fluctuation rates can reach several tens of percents [e.g. J.A. Boedo, J. Nucl. Mater. 390-391 (2009) 29-37]. In this work, the role of turbulence on the radiated power is investigated with a statistical formalism. A special emphasis is devoted to the role of temperature fluctuations, successively for low-frequency fluctuations and in the general case where the characteristic turbulence frequencies can be comparable to the collisional and radiative rates.

  5. Fluctuations induced extinction and stochastic resonance effect in a model of tumor growth with periodic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Li Dongxi, E-mail: lidongxi@mail.nwpu.edu.c [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China); Xu Wei; Guo, Yongfeng; Xu Yong [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2011-01-31

    We investigate a stochastic model of tumor growth derived from the catalytic Michaelis-Menten reaction with positional and environmental fluctuations under subthreshold periodic treatment. Firstly, the influences of environmental fluctuations on the treatable stage are analyzed numerically. Applying the standard theory of stochastic resonance derived from the two-state approach, we derive the signal-to-noise ratio (SNR) analytically, which is used to measure the stochastic resonance phenomenon. It is found that the weak environmental fluctuations could induce the extinction of tumor cells in the subthreshold periodic treatment. The positional stability is better in favor of the treatment of the tumor cells. Besides, the appropriate and feasible treatment intensity and the treatment cycle should be highlighted considered in the treatment of tumor cells.

  6. Fluctuations induced extinction and stochastic resonance effect in a model of tumor growth with periodic treatment

    International Nuclear Information System (INIS)

    Li Dongxi; Xu Wei; Guo, Yongfeng; Xu Yong

    2011-01-01

    We investigate a stochastic model of tumor growth derived from the catalytic Michaelis-Menten reaction with positional and environmental fluctuations under subthreshold periodic treatment. Firstly, the influences of environmental fluctuations on the treatable stage are analyzed numerically. Applying the standard theory of stochastic resonance derived from the two-state approach, we derive the signal-to-noise ratio (SNR) analytically, which is used to measure the stochastic resonance phenomenon. It is found that the weak environmental fluctuations could induce the extinction of tumor cells in the subthreshold periodic treatment. The positional stability is better in favor of the treatment of the tumor cells. Besides, the appropriate and feasible treatment intensity and the treatment cycle should be highlighted considered in the treatment of tumor cells.

  7. The effect of vacuum packaging, EDTA, oregano and thyme oils on the microbiological quality of chicken's breast.

    Science.gov (United States)

    Pavelková, Adriana; Kačániová, Miroslava; Horská, Elena; Rovná, Katarína; Hleba, Lukáš; Petrová, Jana

    2014-10-01

    The effect of ethylenediaminetetraacetate (EDTA), oregano (Origanum vulgare) and thyme (Thymus vulgaris) oils, on the chicken breast fillets was examined in this study. The chicken breast fillets were stored under vacuum packaging (VP), at 4 ± 0.5 °C for a period of 18 days. There were used the following treatments of chicken breast fillets: Air-packaged (AC, control samples), vacuum-packaged (VPC, control samples), VP with EDTA solution 1.50% w/w (VPEC, control samples), VP with oregano oil 0.20% v/w (VP + O) and VP with thyme oil 0.20% v/w, (VP + T). The quality assessment for vacuum packaging of the product in accordance with the terms above and EDTA treatment, oregano and thyme oil was established by microbiological analyzes. The microbiological properties as the total viable counts on Plate Count Agar, after incubation for 2 days at 37 °C and coliform bacteria on Violet Red Bile Glucose agar incubated at 37 °C for 24 h, lactobacilli on Rogosa and Sharpe agar after incubation 48-78 h at 37 °C in an aerobic atmosphere supplemented with carbon dioxide (5% CO2) and Pseudomonas aeruginosa on Pseudomonas Isolation agar (PIA, Oxoid, UK) after incubation at 48 h at 35 °C were monitored. The using of oregano, thyme oil and EDTA with combination of vacuum packaging has significant effects to reduction of all followed groups of microorganisms compared with control group without vacuum packaging and untreated control group. The natural preservatives can be used as alternatives to chemical additives which could extend the meat and meat products shelf life. The knowledge about them can have an important economic feedback by reducing losses attributed to spoilage and by allowing the products to reach distant and new markets. This study shows how using of natural antimicrobials can extend the shelf-life of the meat product. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Quantum fluctuations

    International Nuclear Information System (INIS)

    Reynaud, S.; Giacobino, S.; Zinn-Justin, J.

    1997-01-01

    This course is dedicated to present in a pedagogical manner the recent developments in peculiar fields concerned by quantum fluctuations: quantum noise in optics, light propagation through dielectric media, sub-Poissonian light generated by lasers and masers, quantum non-demolition measurements, quantum electrodynamics applied to cavities and electrical circuits involving superconducting tunnel junctions. (A.C.)

  9. Effects of ion temperature fluctuations on the stability of resistive ballooning modes

    International Nuclear Information System (INIS)

    Singh, R.; Nordman, H.; Jarmen, A.; Weiland, J.

    1996-01-01

    The influence of ion temperature fluctuations on the stability of resistive drift- and ballooning-modes is investigated using a two-fluid model. The Eigenmode equations are derived and solved analytically in a low beta model equilibrium. Parameters relevant to L-mode edge plasmas from the Texas Experimental Tokamak are used. The resistive modes are found to be destabilized by ion temperature fluctuations over a broad range of mode numbers. The scaling of the growth rate with magnetic shear and mode number is elucidated. 13 refs, 4 figs

  10. Correlation analysis of quantum fluctuations and repulsion effects of classical dynamics in SU(3) model

    International Nuclear Information System (INIS)

    Fujiwara, Shigeyasu; Sakata, Fumihiko

    2003-01-01

    In many quantum systems, random matrix theory has been used to characterize quantum level fluctuations, which is known to be a quantum correspondent to a regular-to-chaos transition in classical systems. We present a new qualitative analysis of quantum and classical fluctuation properties by exploiting correlation coefficients and variances. It is shown that the correlation coefficient of the quantum level density is roughly inversely proportional relation to the variance of consecutive phase-space point spacings on the Poincare section plane. (author)

  11. Electron emission of cathode holder of vacuum diode of an intense electron-beam accelerator and its effect on the output voltage

    OpenAIRE

    Xin-Bing Cheng; Jin-Liang Liu; Hong-Bo Zhang; Zhi-Qiang Hong; Bao-Liang Qian

    2011-01-01

    The vacuum diode which is used to generate relativistic electron beams is one of the most important parts of a pulsed-power modulator. In this paper, the electron emission of cathode holder of a vacuum diode and its effect on the output voltage is investigated by experiments on an intense electron-beam accelerator with 180 ns full width at half maximum and 200–500 kV output voltage. First, the field emission is analyzed and the electric field of the vacuum chamber is calculated. Then, the fla...

  12. Vacuum phonon tunneling.

    Science.gov (United States)

    Altfeder, Igor; Voevodin, Andrey A; Roy, Ajit K

    2010-10-15

    Field-induced phonon tunneling, a previously unknown mechanism of interfacial thermal transport, has been revealed by ultrahigh vacuum inelastic scanning tunneling microscopy (STM). Using thermally broadened Fermi-Dirac distribution in the STM tip as in situ atomic-scale thermometer we found that thermal vibrations of the last tip atom are effectively transmitted to sample surface despite few angstroms wide vacuum gap. We show that phonon tunneling is driven by interfacial electric field and thermally vibrating image charges, and its rate is enhanced by surface electron-phonon interaction.

  13. On microscopic structure of the QCD vacuum

    Science.gov (United States)

    Pak, D. G.; Lee, Bum-Hoon; Kim, Youngman; Tsukioka, Takuya; Zhang, P. M.

    2018-05-01

    We propose a new class of regular stationary axially symmetric solutions in a pure QCD which correspond to monopole-antimonopole pairs at macroscopic scale. The solutions represent vacuum field configurations which are locally stable against quantum gluon fluctuations in any small space-time vicinity. This implies that the monopole-antimonopole pair can serve as a structural element in microscopic description of QCD vacuum formation.

  14. Assessment of Pressure Fluctuation Effect for Thermal Fatigue in a T-junction Using Thermo-Hydro Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pyo, Jaebum; Kim, Jungwoo; Huh, Namsu [Seoul National Univ. of Science and Technology, Seoul (Korea, Republic of); Kim, Sunhye [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2013-10-15

    As a result, when evaluating thermal fatigue for the mixing tee, temperature fluctuation is dominant for this phenomenon, it can be reasonably assumed that the pressure is constant on the pipe inner wall. Recently, thermal fatigue due to mixing of the fluids having different temperatures has been considered as an important issue on the fatigue evaluation of nuclear piping. Mainly, this phenomenon occurs in a T-junction operating with the fluids consisted of different temperatures. Because of the turbulent mixing of hot and cold water, the temperature on the inner wall of the pipe fluctuates rapidly, causing the variation of thermal stresses in the pipe and resulting in high cycle thermal fatigue. In practice, cracking by high cycle thermal fatigue is reported at a T-junction in the residual heat removal system at Civaux unit 1 in France. However, because of irregular flow inside the pipe, the pressure also fluctuates rapidly as well as temperature in the inner wall of the pipe. Therefore, in this paper, three-dimensional thermo-hydro analysis was performed for the mixing tee of the shutdown cooling system of the pressurized water reactor plant, examining the pressure variation at the pipe inner wall. Based on the analysis result, this study aims at assessing the pressure fluctuation effect on the thermal fatigue. In this paper, it is verified that there is pressure fluctuation as well as temperature on the inner wall of mixing tee operating with the fluids having different temperatures. However, since the amplitude of pressure is relatively smaller than design pressure of the shutdown cooling system, the effect wouldn't be important for the thermal fatigue.

  15. Experimental investigation on effect of inlet velocity ratios for 3-D temperature fluctuation caused by coaxial-jet flow

    International Nuclear Information System (INIS)

    Cao Qiong; Lu Daogang; Zhang Pan; Shi Wenbo; Tian Lu

    2012-01-01

    An experiment was performed to study the effect of inlet velocity ratios for 3-D temperature fluctuation caused by coaxial-jet flows based on the 3-D temperature and 2-D velocity fields. The experiment results show that the mixing behavior is completed at the bottom of test section in R<1 condition. The averaged temperatures at the bottom of the flow field are asymmetric in R1 condition, the intensities of temperature fluctuations are less than those in R≤1 conditions. The strong temperature fluctuations occur in the regions between the hot and cold flow, as well as between the hot flow and environmental flow in this case. The frequencies of temperature fluctuations are less than 7 Hz. (authors)

  16. Effect of magnetic fluctuations on the confinement and dynamics of runaway electrons in the HT-7 tokamak

    International Nuclear Information System (INIS)

    Zhou, R.J.; Hu, L.Q.; Li, E.Z.; Xu, M.; Zhong, G.Q.; Xu, L.Q.; Lin, S.Y.

    2013-01-01

    Experimental results in the HT-7 tokamak indicated significant losses of runaway electrons due to magnetic fluctuations, but the loss processes did not only rely on the fluctuation amplitude. Efficient radial runaway transport required that there were no more than small regions of the plasma volume in which there was very low transport of runaways. A radial runaway diffusion coefficient of D_r ≈ 10 m"2s"-"1 was derived for the loss processes, and diffusion coefficient near the resonant magnetic surfaces and shielding factor ϒ = 0.8 were deduced. Test particle equations were used to analyze the effect of magnetic fluctuations on runaway dynamics. It was found that the maximum energy that runaways can gain is very sensitive to the value of a_s. a_s = (0.28 - 0.33) was found for the loss processes in the experiment, and maximum runaway energy could be controlled in the range of E = (4 MeV - 6 MeV) in this case. Additionally, to control the maximum runaway energy below 5 MeV, the normalized electric field needed to be under a critical value D_a = 6.8, and the amplitude normalized magnetic fluctuations b tilde needed to be at least of the order of b tilde ≈ 3 x 10"-"5. (author)

  17. The effect of interaural-time-difference fluctuations on apparent source width

    DEFF Research Database (Denmark)

    Käsbach, Johannes; May, Tobias; Oskarsdottir, Gudrun

    2014-01-01

    For the perception of spaciousness, the temporal fluctuations of the interaural time differences (ITDs) and interaural level differences (ILDs) provide important binaural cues. One major characteristic of spatial perception is apparent source width (ASW), which describes the perceived width of a ...

  18. Effect of hydrocarbon-contaminated fluctuating groundwater on magnetic properties of shallow sediments

    Czech Academy of Sciences Publication Activity Database

    Ameen, N. N.; Klueglein, N.; Appel, E.; Petrovský, Eduard; Kappler, A.; Leven, C.

    2014-01-01

    Roč. 58, č. 3 (2014), s. 442-460 ISSN 0039-3169 R&D Projects: GA MŠk(CZ) LG13042 Institutional support: RVO:67985530 Keywords : environmental magnetism * magnetic susceptibility * groundwater table fluctuation * hydrocarbon contamination * magnetite formation Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.806, year: 2014

  19. Cosmological evolution of vacuum and cosmic acceleration

    International Nuclear Information System (INIS)

    Kaya, Ali

    2010-01-01

    It is known that the unregularized expressions for the stress-energy tensor components corresponding to subhorizon and superhorizon vacuum fluctuations of a massless scalar field in a Friedmann-Robertson-Walker background are characterized by the equation of state parameters ω = 1/3 and ω = -1/3, which are not sufficient to produce cosmological acceleration. However, the form of the adiabatically regularized finite stress-energy tensor turns out to be completely different. By using the fact that vacuum subhorizon modes evolve nearly adiabatically and superhorizon modes have ω = -1/3, we approximately determine the regularized stress-energy tensor, whose conservation is utilized to fix the time dependence of the vacuum energy density. We then show that vacuum energy density grows from zero up to H 4 in about one Hubble time, vacuum fluctuations give positive acceleration of the order of H 4 /M 2 p and they can completely alter the cosmic evolution of the universe dominated otherwise by the cosmological constant, radiation or pressureless dust. Although the magnitude of the acceleration is tiny to explain the observed value today, our findings indicate that the cosmological backreaction of vacuum fluctuations must be taken into account in early stages of cosmic evolution.

  20. Vacuum quantum effect for curved boundaries in static Robertson-Walker space-time

    International Nuclear Information System (INIS)

    Setare, M.R.; Sadeghi, J.

    2009-01-01

    The energy-momentum tensor for a massless conformally coupled scalar field in the region between two curved boundaries in k=-1 static Robertson-Walker space-time is investigated. We assume that the scalar field satisfies the Dirichlet boundary condition on the boundaries. k=-1 Robertson-Walker space is conformally related to the Rindler space, as a result we can obtain vacuum expectation values of energy-momentum tensor for conformally invariant field in Robertson-Walker space from the corresponding Rindler counterpart by the conformal transformation.

  1. Scattering effects of small-scale density fluctuations on reflectometric measurements in a tokamak plasma

    International Nuclear Information System (INIS)

    Garcia, J.P.; Manso, M.E.; Serra, F.M.; Mendonca, J.T.

    1989-01-01

    When a wave propagates in a non homogeneous fluctuating plasma part of the incident energy is scattered out to the nonlinear interaction between the wave and the oscillating modes perturbing the plasma. The possibility of enhanced scattering at the cutoff layer, where reflection of the incident wave occurs, has been recently suggested as the basis of a reflectometric experiment to determine the spatial location of small scale fluctuations in a fusion plasma. Here we report on the development of a theoretical model to evaluate the flux of energy scattered by fluctuations, in order to give insight about the interpretation of measurements using a microwave reflectometry diagnostic in a tokamak. The scattered field is obtained through the resolution of a (non-homogeneous) wave propagation equation where the source term is related with the nonlinear current due to the interaction between the incident wave and local fluctuations. We use a slab model for the plasma, and an ordinary (0) wave propagation along the density gradient is considered. The amplitude of the scattered wave at the border of the plasma is estimated. In order to know the contributions to the energy scattered both from the propagation region and the reflecting layer, an approach was used where perturbations are modelled by spatial step functions at several layers. The main contribution to the scattered power comes from the cutoff region, where the electric field amplitude swells as compared with the incident value. Considering the reflectometric system recently installed on the ASDEX tokamak, and using typical density profiles, expected values of the 'swelling factor' have been numerically evaluated. The role of incoherent scattering due to drift wave activity is discussed as well as the coherent scattering due to fluctuations induced by lower hybrid (LH) waves. (author) 2 refs., 4 figs

  2. Effect of ageing time in vacuum package on veal longissimus dorsi and biceps femoris physical and sensory traits

    Directory of Open Access Journals (Sweden)

    G. Baldi

    2015-09-01

    Full Text Available Study evaluated the effects of vacuum ageing (2, 4, 6, 8, 10, 12, 16 days on veal loin (longissimus dorsi; LD and silverside (biceps femoris; BF physical and sensory characteristics. Ageing did not affect cooking loss, increased LD pH and L*, a* and b* in both muscles. Shear force (SF decreased until day 6 in LD and day 10 in BF. Aroma, flavor and taste were not affected, while texturetraits were improved. SF was negative correlated with tenderness and juiciness and positive correlated with BF fibrousness and stringy sensation. Ageing improved texture properties withoutaltering other sensory traits.

  3. Study of cavity effect in micro-Pirani gauge chamber with improved sensitivity for high vacuum regime

    Directory of Open Access Journals (Sweden)

    Guohe Zhang

    2018-05-01

    Full Text Available Ultra-low pressure application of Pirani gauge needs significant improvement of sensitivity and expansion of measureable low pressure limit. However, the performance of Pirani gauge in high vacuum regime remains critical concerns since gaseous thermal conduction with high percentage is essential requirement. In this work, the heat transfer mechanism of micro-Pirani gauge packaged in a non-hermetic chamber was investigated and analyzed compared with the one before wafer-level packaging. The cavity effect, extremely important for the efficient detection of low pressure, was numerically and experimentally analyzed considering the influence of the pressure, the temperature and the effective heat transfer area in micro-Pirani gauge chamber. The thermal conduction model is validated by experiment data of MEMS Pirani gauges with and without capping. It is found that nature gaseous convection in chamber, determined by the Rayleigh number, should be taken into consideration. The experiment and model calculated results show that thermal resistance increases in the molecule regime, and further increases after capping due to the suppression of gaseous convection. The gaseous thermal conduction accounts for an increasing percentage of thermal conduction at low pressure while little changes at high pressure after capping because of the existence of cavity effect improving the sensitivity of cavity-effect-influenced Pirani gauge for high vacuum regime.

  4. Effect of radurization on microbial flora of vacuum-packaged trout (Salmo gairdneri)

    Energy Technology Data Exchange (ETDEWEB)

    Ehlermann, D; Diehl, J F; Hussain, A M [Bundesforschungsanstalt fuer Ernaehrung, Karlsruhe (Germany, F.R.). Inst. fuer Strahlentechnologie

    1976-11-01

    The microbial spoilage pattern was studied for nonirradiated and irradiated (100 and 200 krad) vacuum-packed trout during storage under melting crushed ice. Total microbial count from original nonirradiated fish before storage amounted to 5 x 10/sup 3//g. The value increased to 5 x 10/sup 8//g for the vacuum-packed nonirradiated sample after one month storage. At the end of the same period, total counts in fish treated with 100 and 200 krad increased to 10/sup 7/ and 5 x 10/sup 6/ per g, respectively. Microorganisms isolated from nonirradiated starting material, in order of decreasing number, consisted of Pseudomonas, Flavobacterium, Achromobacter-Moraxella, yeasts, Bacillus, Proteus, Aeromonas, Micrococcus, and few Lactobacillus and Corynebacterium. During storage and with the program of spoilage, the pattern of the microbial flora was shifted. Pseudomonas, initially dominating, were almost eliminated after two weeks storage, while Bacillus and Proteus became predominant. In the irradiated fish, regardless of the dose, Achromobacter-Moraxella, Micrococcus and Lactobacillus became dominant throughout the storage period.

  5. Plasma instability of a vacuum arc centrifuge

    International Nuclear Information System (INIS)

    Hole, M.J.; Dallaqua, R.S.; Simpson, S.W.; Del Bosco, E.

    2002-01-01

    Ever since conception of the vacuum arc centrifuge in 1980, periodic fluctuations in the ion saturation current and floating potential have been observed in Langmuir probe measurements in the rotation region of a vacuum arc centrifuge. In this work we develop a linearized theoretical model to describe a range of instabilities in the vacuum arc centrifuge plasma column, and then test the validity of the description through comparison with experiment. We conclude that the observed instability is a 'universal' instability, driven by the density gradient, in a plasma with finite conductivity

  6. Experimental program to study the physical vacuum: high-energy nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    Willis, W.

    1981-01-01

    Quarks and gluons exist; they are nearly massless, but it is very hard or even impossible to knock them out of the proton. It is now widely believed that this strange state of affairs is due to the properties of the physical vacuum state as it now exists in our part of the Universe. On this view, the ground state of the vacuum is not that familiar in quantum electrodynamics (QED). That state is basically empty space, perturbed by fluctuations which occasionally give rise to a virtual electron-positron pair. In the quantum chromodynamic (QCD) theory of quarks and gluons, the stronger and more complicated forces give rise to a state which cannot be described as a perturbation on empty space. Instead, the physical vacuum has properties which resemble those of a physical medium. For example, the color field is completely excluded, or at least strongly repelled, from a macroscopic volume of physical vacuum. This effect confines the quarks and gluons which carry color, inside the hadrons. On the scale of hadrons, quantum fluctuations make the phenomena more complex, but a simple picture postulates that the strong color fields inside the hadron create a local volume of space more like the perturbative vacuum state, reverting to the physical vacuum state outside. This concept has been quantitatively expressed by the bag model, with some success. It seems that the physical vacuum has acquired properties reminiscent of Maxwell's ether. At least, so we are asked to believe. Maxwell introduced his ether for plausible reasons, but crucial experimental tests were found, and the theory was found wanting. In this talk, experiments for testing the idea that the physical vacuum is not identical to the perturbative one are discussed

  7. Experiment for transient effects of sudden catastrophic loss of vacuum on a scaled superconducting radio frequency cryomodule

    International Nuclear Information System (INIS)

    Dalesandro, A.; Theilacker, J.; Van Sciver, S.W.

    2011-01-01

    Safe operation of superconducting radio frequency (SRF) cavities require design consideration of a sudden catastrophic loss of vacuum (SCLV) adjacent with liquid helium (LHe) vessels and subsequent dangers. An experiment is discussed to test the longitudinal effects of SCLV along the beam line of a string of scaled SRF cavities. Each scaled cavity includes one segment of beam tube within a LHe vessel containing 2 K saturated LHe, and a riser pipe connecting the LHe vessel to a common gas header. At the beam tube inlet is a fast acting solenoid valve to simulate SCLV and a high/low range orifice plate flow-meter to measure air influx to the cavity. The gas header exit also has an orifice plate flow-meter to measure helium venting the system at the relief pressure of 0.4 MPa. Each cavity is instrumented with Validyne pressure transducers and Cernox thermometers. The purpose of this experiment is to quantify the time required to spoil the beam vacuum and the effects of transient heat and mass transfer on the helium system. Heat transfer data is expected to reveal a longitudinal effect due to the geometry of the experiment. Details of the experimental design criteria and objectives are presented.

  8. Investigations by the surface photo-E. M. F. method of the effect of low temperature vacuum baking of an Si(111) surface

    Energy Technology Data Exchange (ETDEWEB)

    Dlugosz, B.; Kochowski, S.

    1982-02-26

    Investigations of the effect of low temperature vacuum baking on the surface potential of silicon are reported. The surface potential Vsub(s0) was measured by the surface photo-e.m.f. method. No noticeable changes in Vsub(s0) occurred after baking of samples which had been freshly etched in HF for 2 h in a vacuum of 6.6 x 10/sup -3/ Pa (5 x 10/sup -5/ Torr) at temperatures of 573, 623 and 723 K. Radical changes were observed when the samples had been aged in air for 2 months before vacuum baking. These results suggest that the direction and the value of the surface potential changes during vacuum baking are determined by the initial surface state.

  9. Fluctuations of cytoskeleton-bound microbeads-the effect of bead-receptor binding dynamics

    International Nuclear Information System (INIS)

    Metzner, C; Raupach, C; Mierke, C T; Fabry, B

    2010-01-01

    The cytoskeleton (CSK) of living cells is a crosslinked fiber network, subject to ongoing biochemical remodeling processes that can be visualized by tracking the spontaneous motion of CSK-bound microbeads. The bead motion is characterized by anomalous diffusion with a power-law time evolution of the mean square displacement (MSD), and can be described as a stochastic transport process with apparent diffusivity D and power-law exponent β: MSD ∼ D (t/t 0 ) β . Here we studied whether D and β change with the time that has passed after the initial bead-cell contact, and whether they are sensitive to bead coating (fibronectin, integrin antibodies, poly-L-lysine, albumin) and bead size (0.5-4.5 μm). The measurements are interpreted in the framework of a simple model that describes the bead as an overdamped particle coupled to the fluctuating CSK network by an elastic spring. The viscous damping coefficient characterizes the degree of bead internalization into the cell, and the spring constant characterizes the strength of the binding of the bead to the CSK. The model predicts distinctive signatures of the MSD that change with time as the bead couples more tightly to the CSK and becomes internalized. Experimental data show that the transition from the unbound to the tightly bound state occurs in an all-or-nothing manner. The time point of this transition shows considerable variability between individual cells (2-30 min) and depends on the bead size and bead coating. On average, this transition occurs later for smaller beads and beads coated with ligands that trigger the formation of adhesion complexes (fibronectin, integrin antibodies). Once the bead is linked to the CSK, however, the ligand type and bead size have little effect on the MSD. On longer timescales of several hours after bead addition, smaller beads are internalized into the cell more readily, leading to characteristic changes in the MSD that are consistent with increased viscous damping by the

  10. Optical Properties of Quantum Vacuum. Space-Time Engineering

    International Nuclear Information System (INIS)

    Gevorkyan, A. S.; Gevorkyan, A. A.

    2011-01-01

    The propagation of electromagnetic waves in the vacuum is considered taking into account quantum fluctuations in the limits of Maxwell-Langevin (ML) type stochastic differential equations. For a model of fluctuations, type of 'white noise', using ML equations a partial differential equation of second order is obtained which describes the quantum distribution of virtual particles in vacuum. It is proved that in order to satisfy observed facts, the Lamb Shift etc, the virtual particles should be quantized in unperturbed vacuum. It is shown that the quantized virtual particles in toto (approximately 86 percent) are condensed on the 'ground state' energy level. It is proved that the extension of Maxwell electrodynamics with inclusion of quantum vacuum fluctuations may be constructed on a 6D space-time continuum, where 4D is Minkowski space-time and 2D is a compactified subspace. In detail is studied of vacuum's refraction indexes under the influence of external electromagnetic fields.

  11. Fluctuation mechanisms in superconductors nanowire single-photon counters, enabled by effective top-down manufacturing

    CERN Document Server

    Bartolf, Holger

    2016-01-01

    Holger Bartolf discusses state-of-the-art detection concepts based on superconducting nanotechnology as well as sophisticated analytical formulæ that model dissipative fluctuation-phenomena in superconducting nanowire single-photon detectors. Such knowledge is desirable for the development of advanced devices which are designed to possess an intrinsic robustness against vortex-fluctuations and it provides the perspective for honorable fundamental science in condensed matter physics. Especially the nanowire detector allows for ultra-low noise detection of signals with single-photon sensitivity and GHz repetition rates. Such devices have a huge potential for future technological impact and might enable unique applications (e.g. high rate interplanetary deep-space data links from Mars to Earth). Contents Superconducting Single-Photon Detectors Nanotechnological Manufacturing; Scale: 10 Nanometer Berezinskii-Kosterlitz Thouless (BKT) Transition, Edge-Barrier, Phase Slips Target Groups Researchers and students of...

  12. Transport and fluctuations in granular fluids from Boltzmann equation to hydrodynamics, diffusion and motor effects

    CERN Document Server

    Puglisi, Andrea

    2015-01-01

    This brief offers a concise presentation of granular fluids from the  point of view of non-equilibrium statistical physics. The emphasis is on fluctuations, which can be large in granular fluids due to the small system size (the number of grains is many orders of magnitude smaller than in molecular fluids). Firstly, readers will be introduced to the most intriguing experiments on fluidized granular fluids. Then granular fluid theory, which goes through increasing levels of coarse-graining and emerging collective phenomena, is described. Problems and questions are initially posed at the level of kinetic theory, which describes particle densities in full or reduced phase-space. Some answers become clear through hydrodynamics, which describes the evolution of slowly evolving fields. Granular fluctuating hydrodynamics, which builds a bridge to the most recent results in non-equilibrium statistical mechanics, is also introduced. Further and more interesting answers come when the dynamics of a massive intruder are...

  13. Ion temperature and ∇B effects on ULF fluctuations at the magnetopause

    International Nuclear Information System (INIS)

    Pillay, R.

    1996-01-01

    In this paper, we present an extension of the work by Lakhina, Shukla and Stenflo (Geophys. Res. Lett. 20, 2419 1993) on the generation of ultralow frequency (ULF) fluctuations at the earth's magnetopause. A high beta model for the generation of these short wavelength fluctuations is described. In this model, drifts due to density and magnetic field gradients, present at the magnetopause, act as free energy sources for the excitation of the ULF waves. The model also considers both warm electrons and ions and is based on the SS equations (Shukla and Stenflo. J. Exp. Theor. Phys. 57, 692 1993) for low-frequency EM waves in non-uniform high beta magnetoplasmas. Using fluid theory the associated dispersion relation is first established, then numerically solved for unstable modes in different regions of parameter space. (orig.)

  14. Fluctuating functions related to quality of life in advanced Parkinson disease: effects of duodenal levodopa infusion

    DEFF Research Database (Denmark)

    Isacson, D; Bingefors, K; Sønbø Kristiansen, Ivar

    2008-01-01

    OBJECTIVE: To assess fluctuations in quality of life (QoL) and motor performance in patients with advanced Parkinson disease (PD) treated with continuous daytime duodenal levodopa/carbidopa infusion or conventional therapy. METHODS: Of 18 patients completing a 6-week trial (DIREQT), 12 were...... followed for up to 6 months and assessed using electronic diaries and the PD Questionnaire-39 (PDQ-39). RESULTS: During the trial and follow-up, major diurnal fluctuations were observed, especially for hyperkinesia, 'off' time, ability to walk and depression. Duodenal infusion was associated...... with significantly more favourable outcomes compared with conventional treatment for satisfaction with overall functioning, 'off' time and ability to walk, with improved outcomes with PDQ-39. CONCLUSIONS: Relative to conventional treatment, infusion therapy may stabilize and significantly improve motor function...

  15. The Effects of Sex Hormonal Fluctuations during Menstrual Cycle on Cortical Excitability and Manual Dexterity (a Pilot Study.

    Directory of Open Access Journals (Sweden)

    Maryam Zoghi

    Full Text Available To investigate whether hormonal fluctuations during the menstrual cycle affect corticospinal excitability, intracortical inhibition (ICI or facilitation (ICF in primary motor cortex, and also whether the hormonal fluctuations have any effect on manual dexterity in neurologically intact women.Twenty volunteers (10 Female, 10 Male were included in this study. The levels of progesterone and estradiol were measured from saliva during the women's menstrual follicular, ovulation and mid-luteal phases. Motor evoked potentials were recorded from the right first dorsal interosseous muscle. Single and paired-pulse Transcranial Magnetic Stimulation (TMS were delivered in a block of 20 stimuli. With paired-pulse technique, 3ms and 10ms inter-stimulus intervals were used to assess ICI and ICF, respectively. The Grooved Pegboard Test (GPT was completed in each session before the TMS assessments. Male participants were tested at similar time intervals as female participants.Mixed design ANOVA revealed that GPT score in female participants was significantly lower at the mid-luteal phase compared to the ovulation phase (p = 0.017. However, it was not correlated with progesterone or estrogen fluctuations during the menstrual cycle. The results also showed that the effect of phase, sex and the interaction of phase by sex for resting motor threshold, ICI or ICF were not significant (p > 0.05.Manual dexterity performance fluctuates during the menstrual cycle in neurologically intact women, which might be due to the balance of the neuromodulatory effects of P4 and E2 in the motor cortex during different phases.

  16. Research on the Dividend Policy of Listed Company and Fluctuation Effect of Stock Market

    Directory of Open Access Journals (Sweden)

    Wang Hua

    2015-01-01

    Full Text Available Based on the dividend policy and theory, this article takes the events that A stock of all the listed banking companies (16 in total issued dividend in the CSI stock market for 5 years from 2008 to 2012 as the investigation samples to inspect the relevance of dividend policy with the fluctuation of stock price and transaction volume, thus to prove the dividend policy is an efficient mechanism for information transmission.

  17. Lithium line radiation in turbulent edge plasmas: Effects of low and high frequency temperature fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Rosato, J., E-mail: joel.rosato@univ-provence.fr [PIIM, UMR 6633, Universite de Provence/CNRS, Centre de St.-Jerome, Case 232, F-13397 Marseille Cedex 20 (France); Capes, H.; Catoire, F. [PIIM, UMR 6633, Universite de Provence/CNRS, Centre de St.-Jerome, Case 232, F-13397 Marseille Cedex 20 (France); Kadomtsev, M.B.; Levashova, M.G.; Lisitsa, V.S. [ITP, Russian Research Center ' Kurchatov Institute' , Moscow (Russian Federation); Marandet, Y. [PIIM, UMR 6633, Universite de Provence/CNRS, Centre de St.-Jerome, Case 232, F-13397 Marseille Cedex 20 (France); Rosmej, F.B. [LULI, UMR 7605, Universite Pierre et Marie Curie/CNRS, 4 Place Jussieu, Case 128, F-75252 Paris Cedex 05 (France); Stamm, R. [PIIM, UMR 6633, Universite de Provence/CNRS, Centre de St.-Jerome, Case 232, F-13397 Marseille Cedex 20 (France)

    2011-08-01

    In lithium-wall-conditioned tokamaks, the line radiation due to the intrinsic impurities (Li/Li{sup +}/Li{sup ++}) plays a significant role on the power balance. Calculations of the radiation losses are usually performed using a stationary collisional-radiative model, assuming constant values for the plasma parameters (N{sub e}, T{sub e},...). Such an approach is not suitable for turbulent plasmas where the various parameters are time-dependent. This is critical especially for the edge region, where the fluctuation rates can reach several tens of percents [e.g. J.A. Boedo, J. Nucl. Mater. 390-391 (2009) 29-37]. In this work, the role of turbulence on the radiated power is investigated with a statistical formalism. A special emphasis is devoted to the role of temperature fluctuations, successively for low-frequency fluctuations and in the general case where the characteristic turbulence frequencies can be comparable to the collisional and radiative rates.

  18. Effects of vacuum annealing on the optical and electrical properties of p-type copper-oxide thin-film transistors

    International Nuclear Information System (INIS)

    Sohn, Joonsung; Song, Sang-Hun; Kwon, Hyuck-In; Nam, Dong-Woo; Cho, In-Tak; Lee, Jong-Ho; Cho, Eou-Sik

    2013-01-01

    We have investigated the effects of vacuum annealing on the optical and electrical properties of the p-type copper-oxide thin-film transistors (TFTs). The vacuum annealing of the copper-oxide thin-film was performed using the RF magnetron sputter at various temperatures. From the x-ray diffraction and UV-vis spectroscopy, it is demonstrated that the high-temperature vacuum annealing reduces the copper-oxide phase from CuO to Cu 2 O, and increases the optical transmittance in the visible part of the spectrum. The fabricated copper-oxide TFT does not exhibit the switching behavior under low-temperature vacuum annealing conditions. However, as the annealing temperature increases, the drain current begins to be modulated by a gate voltage, and the TFT exhibits a high current on–off ratio over 10 4 as the vacuum annealing temperature increases over 450 °C. These results show that the vacuum annealing process can be an effective method of simultaneously improving the optical and electrical performances in p-type copper-oxide TFTs. (paper)

  19. Effect of vacuum-packaging and low dose gamma irradiation on the microbial, bio-chemical quality and shelf life of peeled shrimp (Litopenaeus vannamei) during ice storage

    International Nuclear Information System (INIS)

    Bojayanaik, Manjanaik; Naroth, Kavya; Prasad, Surjith; Shetty, Veena; Hiriyur, Somashekarappa; Patil, Rajashekar

    2015-01-01

    The present investigation was carried out to see the combined effect of vacuum packaging and low dose gamma irradiation (3kGy) on the shelf life of peeled and undeveined shrimp (Litopeanus vannamie) during ice storage. The fresh farm raised shrimps were peeled and un deveined, packed in high density polyethylene bags (aerobic and vacuum packaging) and were divided into four groups viz. control (C), Irradiated (I), Vacuum packed (V) and vacuum-packed with irradiation (VI). The two groups (I and VI) were irradiated at 3 kGy (Dose rate at the rate 6.043 kGy/hr) and aseptically stored in ice in an insulated polystyrene box. All the samples were periodically analysed for microbial (Total bacterial load, total Coliform, Faecal Coliforms, Staphylococcus, Salmonella, Vibrios and E. coli) and bio chemical (TVB-N, TMA, TBARS and pH) quality. The results revealed that the combination of low dose gamma irradiation and vacuum packaging had a significant effect on microbial load (p>0.05). The TVB-N, TMA-N, TBARS and pH were significantly lower in vacuum packed with irradiation when compare to non-irradiated and aerobically packed shrimp (p> 0.05), and shelf life of peeled shrimp extended up to 21 days in ice storage. (author)

  20. Effect of Blood Glucose Fluctuation on Some Trace Elements and Aldosterone Hormone among Type II Diabetic Patients with Metabolic Syndrome

    International Nuclear Information System (INIS)

    Ezz El-Arab, A.; El Fouly, A.H.; Mahmoud, H.H.

    2014-01-01

    There is accumulating evidence determine that the metabolism of some trace elements is altered in diabetes mellitus (DM) type II. The current study aimed to evaluate the effect of serum blood glucose fluctuation during (Random, Fasting and Postprandial 2 hours state) on some trace elements such as Cadmium (Cd), Chromium (Cr), Manganese (Mn), Magnesium (Mg), Zinc (Zn), Copper (Cu), Sodium (Na), Potassium (K), and Aldosterone hormone in type II Diabetic patients associated with metabolic syndrome in comparison with healthy volunteers. The International Diabetes Federation (IFD) consensus the diagnosis of metabolic syndrome according to central obesity, lipid profile, blood glucose level and blood pressure. A significant change was observed in trace elements level (Cd, Cr, Mg, Mn, Zn, Cu, Na, and K) and Aldosterone hormone as a result of glucose fluctuation among type II diabetic patients.

  1. Longitudinal analysis of the effect of academic failure tolerance on academic achievement fluctuation in medical school students.

    Science.gov (United States)

    Chae, Su Jin; Kim, Miran; Chang, Ki Hong

    2016-03-01

    Academic failure tolerance (AFT) is one of the important psychological concepts in education, but its applications in medical education are rare. Thus, the purpose of this study was to investigate the effect of academic failure tolerance on academic achievement fluctuation among medical school students using a longitudinal research design. The subjects were 43 medical students who responded to the AFT test. This study analyzed the longitudinal data of achievement scores up to the 2nd academic year (2012-2013) among students who were divided into academic achievement improvement and decline groups. Comparing the improvement and decline groups' mean academic achievement fluctuation scores demonstrated that behavior and preferred task difficulty showed high scores whereas feeling scores were lower in the improvement group (pimportant basis for enhancing academic achievement among medical students.

  2. CaE-T zeolite - a new effective adsorber for vacuum technique

    International Nuclear Information System (INIS)

    Skvazyvaev, V.E.; Khvoshchev, S.S.; Zhdanov, S.P.

    1975-01-01

    Adsorption of air at low pressures on type E zeolites was studied as a function of their composition and dehydration regime. It was shown that zeolite CaE-T has a greatly increased sorption capacity for air at low pressures and that this is more than 3 times that of industrial zeolites currently used in vacuum technology. Mass-spectrometer studies were made of the gas phase over zeolites type E and A after adsorption of air at pressures from 10 -8 to 10 -5 mm Hg at liquid nitrogen temperatures under conditions approximating equilibrium. It was shown that zeolite CaE-T has a high adsorption capacity for Ar, O 2 , and H 2 . Adsorption of H 2 and Ar by zeolites of different structural types at low pressures was studied. It was shown that zeolite CaE-T has a significantly higher adsorption capacity for hydrogen and argon than all industrial zeolites

  3. Investigation of the noise effect on tomographic reconstructions for a tangentially viewing vacuum ultraviolet imaging diagnostic

    International Nuclear Information System (INIS)

    Ming, Tingfeng; Ohdachi, Satoshi; Suzuki, Yasuhiro

    2011-01-01

    Tomographic reconstruction for a tangentially viewing two-dimensional (2D) imaging system is studied. A method to calculate the geometry matrix in 2D tomography is introduced. An algorithm based on a Phillips-Tikhonov (P-T) type regularization method is investigated, and numerical tests using the P-T method are conducted with both tokamak and Heliotron configurations. The numerical tests show that the P-T method is not sensitive to the added noise levels and the emission profiles with higher mode numbers can be reconstructed with adequate resolution. The results indicate that this method is suitable for 2D tomographic reconstruction for a tangentially viewing vacuum ultraviolet telescope system. (author)

  4. Effects of mode profile on tunneling and traversal of ultracold atoms through vacuum-induced potentials

    Science.gov (United States)

    Badshah, Fazal; Irfan, Muhammad; Qamar, Sajid; Qamar, Shahid

    2016-04-01

    We consider the resonant interaction of an ultracold two-level atom with an electromagnetic field inside a high-Q micromaser cavity. In particular, we study the tunneling and traversal of ultracold atoms through vacuum-induced potentials for secant hyperbolic square and sinusoidal cavity mode functions. The phase time which may be considered as an appropriate measure of the time required for the atoms to cross the cavity, significantly modifies with the change of cavity mode profile. For example, switching between the sub and superclassical behaviors in phase time can occur due to the mode function. Similarly, negative phase time appears for the transmission of the two-level atoms in both excited and ground states for secant hyperbolic square mode function which is in contrast to the mesa mode case.

  5. Effect of process parameters on power requirements of vacuum swing adsorption technology for CO2 capture from flue gas

    International Nuclear Information System (INIS)

    Zhang, Jun; Webley, Paul A.; Xiao, Penny

    2008-01-01

    This study focuses on the effects of process and operating parameters - feed gas temperature, evacuation pressure and feed concentration - on the performance of carbon dioxide vacuum swing adsorption (CO 2 VSA) processes for CO 2 capture from gas, especially as it affects power consumption. To obtain reliable data on the VSA process, experimental work was conducted on a purposely built three bed CO 2 VSA pilot plant using commercial 13X zeolite. Both 6 step and 9 step cycles were used to determine the influences of temperature, evacuation pressure and feed concentration on process performance (recovery, purity, power and corresponding capture cost). A simple economic model for CO 2 capture was developed and employed herein. Through experiments and analysis, it is found that the feed gas temperature, evacuation pressure and feed concentration have significant effects on power consumption and CO 2 capture cost. Our data demonstrate that the CO 2 VSA process has good recovery (>70%), purity (>90%) and low power cost (4-10 kW/TPDc) when operating with 40 C feed gas provided relatively deep vacuum is used. Enhanced performance is obtained when higher feed gas concentration is fed to the plant, as expected. Our data indicates large potential for application of CO 2 VSA to CO 2 capture from flue gas. (author)

  6. Scroll vacuum pump

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, Etsuo; Suganami, Takuya; Nishida, Mitsuhiro; Kitora, Yoshihisa; Yamamoto, Sakuei; Fujii, Kosaburo

    1988-02-25

    An effort is made to apply a scroll machine to development of a vacuum pump. In view of mechanical simplification and load patterns, the vacuum pump uses a rotating mechanism to produce paired vortices rotating around each center. Chip seal and atmospheric pressure are utilized for axial gap sealing while a spring and atmospheric pressure for the radial gap sealing. In both gaps, the sealing direction is stationary relative to the environment during rotation, making it much easier to achieve effective sealing as compared to oscillating pumps. Since the compression ratio is high in vacuum pumps, a zero top clearance form is adopted for the central portion of vortices and an gas release valve is installed in the rotating axis. A compact Oldham coupling with a small inertia force is installed behind the vortices to maintain the required phase relations between the vortices. These improvements result in a vacuum of 1 Pa for dry operation and 10/sup -2/ Pa for oil flooded operation of a single-stage scroll machine at 1800 rpm. (5 figs, 1 tab, 4 refs)

  7. Effect of drying methods with the application of vacuum microwaves on the bioactive compounds, color, and antioxidant activity of strawberry fruits.

    Science.gov (United States)

    Wojdyło, Aneta; Figiel, Adam; Oszmiański, Jan

    2009-02-25

    The objective of this study was to evaluate the application of vacuum-microwave drying (240, 360, and 480 W) in the production process of dehydrated strawberry and to compare and contrast the quality of these dehydrated strawberries in terms of their polyphenol compounds, concentration of some heat liable components, and color to that of freeze-dried, convective, and vacuum-dried strawberry. Thus, the effect of vacuum-microwave drying and other drying methods on the antioxidant activity of berries was evaluated. Whole fresh and dried fruits were assessed for phenolics (anthocyanins, flavanols, hydroxycinnamic acids, and flavonols), ascorbic acid, and antioxidant activity (all parameters were calculated on a dry matter basis). Analysis of data shows that ellagic acid and flavanol changes were affected by drying techniques and cultivar. Drying destroyed anthocyanins, flavanols, and ascorbic acid, and there was a significant decrease in antioxidant activity. The most striking result was that conventional and vacuum drying decreased antioxidant activity in both cultivars, whereas contradictory results were found for vacuum-microwave processed strawberry. This study has demonstrated that vacuum-microwave drying, especially at 240 W, can produce high-quality products, with the additional advantage of reduced processing times, compared to other processes such as freeze-drying.

  8. Leybold vacuum handbook

    CERN Document Server

    Diels, K; Diels, Kurt

    1966-01-01

    Leybold Vacuum Handbook presents a collection of data sets that are essential for numerical calculation of vacuum plants and vacuum processes. The title first covers vacuum physics, which includes gas kinetics, flow phenomena, vacuum gauges, and vapor removal. Next, the selection presents data on vacuum, high vacuum process technology, and gas desorption and gettering. The text also deals with materials, vapor pressure, boiling and melting points, and gas permeability. The book will be of great interest to engineers and technicians that deals with vacuum related technologies.

  9. Effect of intrinsic-gain fluctuations on quantum noise of phosphor materials used in medical X-ray imaging

    International Nuclear Information System (INIS)

    Kalivas, N.; Costaridou, L.; Panayiotakis, G.; Nomicos, C.D.

    1999-01-01

    The quality of a medical image depends, among other parameters, on quantum noise. Quantum noise is affected by the fluctuations in the number of optical quanta produced within the phosphor, per absorbed X-ray (i.e. phosphor intrinsic-gain fluctuations). This effect is considered by means of a factor, called in this study intrinsic-gain noise factor, IGNF(E). In existing theoretical models of quantum noise, the corresponding factor is taken to be equal to one. In this paper, an expression that accounts for the coefficient of variation of the phosphor intrinsic gain is introduced. This expression takes into account the process of electron-hole pair conversion to optical photons and the frequency distribution function of the emitted optical photon energy. Subsequently IGNF(E) is expressed in terms of this coefficient of variation. IGNF(E) has been calculated for several phosphors and for various energies. For all medical X-ray energies studied, phosphors that exhibit a high relative fluctuation of emitted optical photon energy, IGNF(E) exceeds by 2% to over 17% the corresponding factor of the existing theoretical models of quantum noise. (orig.)

  10. Influence of drying conditions on the effective diffusivity and activation energy during convective air and vacuum drying of pumpkin

    Directory of Open Access Journals (Sweden)

    Liliana SEREMET (CECLU

    2015-12-01

    Full Text Available The main purpose of the work is to investigate the efficiency of convective air and vacuum processing on pumpkin drying kinetics. The pumpkin samples were of two different geometrical shapes (cylinder and cube and were dried in a laboratory scale hot air dryer using some specific parameters (constant air velocity of 1.0 m/s, three different temperatures 50, 60 and 70ºC suited to relative humidity (RH values of 9.8, 6.5, and 5.4% respectively. The vacuum drying was led at constant pressures of 5 kPa and accordance temperatures of 50, 60 and 70ºC. Moisture transfer from pumpkin slices was described by applying Fick’s diffusion model. Temperature dependence of the effective diffusivity was described by the Arrhenius-type equation. Cylindrical samples have a slightly better behaviour compared to cubic samples, due to the disposition of the tissues, and the mass and thermic transfer possibilities. Analysing the results of both drying methods, it was deduced that the most efficient method is convective air drying at 70ºC.

  11. Test of the beam effect on vacuum arc occurrence in a high-gradient accelerating structure for the CLIC project

    CERN Document Server

    AUTHOR|(CDS)2130409; Gagliardi, Martino

    A new generation of lepton colliders capable of reaching TeV energies is pres- ently under development, and to succeed in this task it is necessary to show that the technology for such a machine is available. The Compact Linear Collider (CLIC) is a possible design option among the future lepton collider projects. It consists of two normal-conducting linacs. Accelerating structures with a gradient of the order of 100 MV/m are necessary to reach the required high energies within a reasonable machine length. One of the strictest require- ments for such accelerating structures is a relatively low occurrence of vacuum arcs. CLIC prototype structures have been tested in the past, but only in absence of beam. In order to proof the feasibility of the high gradient technology for building a functional collider, it is necessary to understand the effect of the beam presence on the vacuum breakdowns. Tests of this type have never been performed previously. The main goal of this work is to provide a first measurement of t...

  12. Investigation of the effect of vacuum environment on the fatigue and fracture behavior of 7075-T6.

    Science.gov (United States)

    Hudson, C. M.

    1972-01-01

    Axial-load fatigue-life, fatigue-crack propagation, and fracture-toughness experiments were conducted on sheet specimens made of 7075-T6 aluminum alloy. These experiments were conducted at air pressures ranging from 101 kN/sq m to 7 micronewtons/sq m to determine the effect of air pressure on fatigue behavior. Analysis of the results from the fatigue-life experiments indicated that for a given stress level, the lower the air pressure was the longer the fatigue life. At a pressure of 7 micronewtons/sq m, fatigue lives were 15 to 30 times longer than at 101 kN/sq m. Analysis of the results from the fatigue-crack-growth experiments indicates that at low values of stress-intensity range, the fatigue-crack-growth rates were approximately twice as high at atmospheric pressure as in vacuum. However, at higher values of stress-intensity range, the fatigue-crack-growth rates were nominally the same in vacuum and at atmospheric pressure.

  13. An innovative intermittent-vacuum assisted thermophilic anaerobic digestion process for effective animal manure utilization and treatment.

    Science.gov (United States)

    Zhang, Renchuan; Anderson, Erik; Addy, Min; Deng, Xiangyuan; Kabir, Fayal; Lu, Qian; Ma, Yiwei; Cheng, Yanling; Liu, Yuhuan; Chen, Paul; Ruan, Roger

    2017-11-01

    Intermittent-vacuum stripping (IVS) was developed as a pretreatment for thermophilic anaerobic digestion (TAD) to improve methanogenesis and hydrolysis activity through preventing free ammonia and hydrogen sulfide (H 2 S) inhibition from liquid swine manure (LSM). Over 98% of ammonia and 38% organic nitrogen were removed in 60min from 55°C to 85°C with vacuum pressure (from 100.63±3.79mmHg to 360.91±7.39mmHg) at initial pH 10.0 by IVS. Thermophilic methanogenesis and hydrolysis activity of pretreated LSM increased 52.25% (from 11.56±1.75% to 17.60±0.49%) in 25days and 40% (from 10days to 6days) in bio-methane potential assay. Over 80% H 2 S and total nitrogen were removed by IVS assistance, while around 70% nitrogen was recycled as ammonium sulfate. Therefore, IVS-TAD combination could be an effective strategy to improve TAD efficiency, whose elution is more easily utilized in algae cultivation and/or hydroponic system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Effects of ZnO nanoparticles and microwave heating on the sterilization and product quality of vacuum-packaged Caixin.

    Science.gov (United States)

    Liu, Qian; Zhang, Min; Fang, Zhong-xiang; Rong, Xiao-hong

    2014-09-01

    The sterilization of vacuum-packaged Caixin (Brassica chinensis L.), which is a green-leafy vegetable and also a low-acid food, remains a difficult problem. In this study, effects of ZnO nanoparticles and microwave heating on the sterilization and product quality of vacuum-packaged Caixin were investigated. Addition of ZnO nanoparticle suspension at 0.01-0.02 g kg(-1) reduced the number of bacterial colonies. The antibacterial activity was enhanced with the increased amount of ZnO nanoparticles. Microwave heating (915 and 2450 MHz) was used to sterilize Caixin samples. Samples had good product quality (better greenness, chroma and hue angle values, lower browning index and acceptable texture) and the lowest total colony number under the microwave heating condition of 400 W 150 s (2450 MHz). The best sterilization condition was observed under 2450 MHz microwave (400 W 150 s) heating combined with 0.02 g kg(-1) ZnO nanoparticle addition, which led to a total colony number of <1 log CFU g(-1) in Caixin samples within 7 days. © 2014 Society of Chemical Industry.

  15. The localized quantum vacuum field

    International Nuclear Information System (INIS)

    Dragoman, D

    2008-01-01

    A model for the localized quantum vacuum is proposed in which the zero-point energy (ZPE) of the quantum electromagnetic field originates in energy- and momentum-conserving transitions of material systems from their ground state to an unstable state with negative energy. These transitions are accompanied by emissions and re-absorptions of real photons, which generate a localized quantum vacuum in the neighborhood of material systems. The model could help resolve the cosmological paradox associated with the ZPE of electromagnetic fields, while reclaiming quantum effects associated with quantum vacuum such as the Casimir effect and the Lamb shift. It also offers a new insight into the Zitterbewegung of material particles

  16. The localized quantum vacuum field

    Energy Technology Data Exchange (ETDEWEB)

    Dragoman, D [Physics Department, University of Bucharest, PO Box MG-11, 077125 Bucharest (Romania)], E-mail: danieladragoman@yahoo.com

    2008-03-15

    A model for the localized quantum vacuum is proposed in which the zero-point energy (ZPE) of the quantum electromagnetic field originates in energy- and momentum-conserving transitions of material systems from their ground state to an unstable state with negative energy. These transitions are accompanied by emissions and re-absorptions of real photons, which generate a localized quantum vacuum in the neighborhood of material systems. The model could help resolve the cosmological paradox associated with the ZPE of electromagnetic fields, while reclaiming quantum effects associated with quantum vacuum such as the Casimir effect and the Lamb shift. It also offers a new insight into the Zitterbewegung of material particles.

  17. Vacuum energy of the electromagnetic field in a rotating system

    International Nuclear Information System (INIS)

    Hacyan, S.; Sarmiento, A.

    1986-01-01

    The vacuum energy of the electromagnetic field is calculated for a uniformly rotating observer. The spectrum of vacuum fluctuations is composed of the zero-point energy with a modified density of states and a contribution due to the rotation which is not thermal. (orig.)

  18. Vacuum expectation values for four-fermion operators. Model estimates

    International Nuclear Information System (INIS)

    Zhitnitskij, A.R.

    1985-01-01

    Some simple models (a system with a heavy quark, the rarefied insatanton gas) are used to investigate the problem of factorizability. Characteristics of vacuum fluctuations responsible for saturation of four-fermion vacuum expectation values which are known phenomenologically are discussed. A qualitative agreement between the model and phenomenologic;l estimates has been noted

  19. Vacuum expectation values of four-fermion operators. Model estimates

    International Nuclear Information System (INIS)

    Zhitnitskii, A.R.

    1985-01-01

    Simple models (a system with a heavy quark, a rarefied instanton gas) are used to study problems of factorizability. A discussion is given of the characteristics of the vacuum fluctuations responsible for saturation of the phenomenologically known four-fermion vacuum expectation values. Qualitative agreement between the model and phenomenological estimates is observed

  20. The influence of the edge density fluctuations on electron cyclotron wave beam propagation in tokamaks

    International Nuclear Information System (INIS)

    Bertelli, N; Balakin, A A; Westerhof, E; Garcia, O E; Nielsen, A H; Naulin, V

    2010-01-01

    A numerical analysis of the electron cyclotron (EC) wave beam propagation in the presence of edge density fluctuations by means of a quasi-optical code [Balakin A. A. et al, Nucl. Fusion 48 (2008) 065003] is presented. The effects of the density fluctuations on the wave beam propagation are estimated in a vacuum beam propagation between the edge density layer and the EC resonance absorption layer. Consequences on the EC beam propagation are investigated by using a simplified model in which the density fluctuations are described by a single harmonic oscillation. In addition, quasi-optical calculations are shown by using edge density fluctuations as calculated by two-dimensional interchange turbulence simulations and validated with the experimental data [O. E. Garcia et al, Nucl. Fusion 47 (2007) 667].

  1. Dual-Material Gate Approach to Suppression of Random-Dopant-Induced Characteristic Fluctuation in 16 nm Metal-Oxide-Semiconductor Field-Effect-Transistor Devices

    Science.gov (United States)

    Li, Yiming; Lee, Kuo-Fu; Yiu, Chun-Yen; Chiu, Yung-Yueh; Chang, Ru-Wei

    2011-04-01

    In this work, we explore for the first time dual-material gate (DMG) and inverse DMG devices for suppressing the random-dopant (RD)-induced characteristic fluctuation in 16 nm metal-oxide-semiconductor field-effect-transistor (MOSFET) devices. The physical mechanism of suppressing the characteristic fluctuation of DMG devices is observed and discussed. The achieved improvement in suppressing the RD-induced threshold voltage, on-state current, and off-state current fluctuations are 28, 12.3, and 59%, respectively. To further suppress the fluctuations, an approach that combines the DMG method and channel-doping-profile engineering is also advanced and explored. The results of our study show that among the suppression techniques, the use of the DMG device with an inverse lateral asymmetric channel-doping-profile has good immunity to fluctuation.

  2. Vacuum in intensive gauge fields

    International Nuclear Information System (INIS)

    Matinian, S.G.

    1977-12-01

    The behaviour of vacuum in a covariantly constant Yang-Mills field is considered. The expressions for the effective Lagrangian in an intensive field representing the asymptotic freedom of the theory are found

  3. Estimating teat canal cross-sectional area to determine the effects of teat-end and mouthpiece chamber vacuum on teat congestion.

    Science.gov (United States)

    Penry, J F; Upton, J; Mein, G A; Rasmussen, M D; Ohnstad, I; Thompson, P D; Reinemann, D J

    2017-01-01

    The primary objective of this experiment was to assess the effect of mouthpiece chamber vacuum on teat-end congestion. The secondary objective was to assess the interactive effects of mouthpiece chamber vacuum with teat-end vacuum and pulsation setting on teat-end congestion. The influence of system vacuum, pulsation settings, mouthpiece chamber vacuum, and teat-end vacuum on teat-end congestion were tested in a 2×2 factorial design. The low-risk conditions for teat-end congestion (TEL) were 40 kPa system vacuum (Vs) and 400-ms pulsation b-phase. The high-risk conditions for teat-end congestion (TEH) were 49 kPa Vs and 700-ms b-phase. The low-risk condition for teat-barrel congestion (TBL) was created by venting the liner mouthpiece chamber to atmosphere. In the high-risk condition for teat-barrel congestion (TBH) the mouthpiece chamber was connected to short milk tube vacuum. Eight cows (32 quarters) were used in the experiment conducted during 0400 h milkings. All cows received all treatments over the entire experimental period. Teatcups were removed after 150 s for all treatments to standardize the exposure period. Calculated teat canal cross-sectional area (CA) was used to assess congestion of teat tissue. The main effect of the teat-end treatment was a reduction in CA of 9.9% between TEL and TEH conditions, for both levels of teat-barrel congestion risk. The main effect of the teat-barrel treatment was remarkably similar, with a decrease of 9.7% in CA between TBL and TBH conditions for both levels of teat-end congestion risk. No interaction between treatments was detected, hence the main effects are additive. The most aggressive of the 4 treatment combinations (TEH plus TBH) had a CA estimate 20% smaller than for the most gentle treatment combination (TEL plus TBL). The conditions designed to impair circulation in the teat barrel also had a deleterious effect on circulation at the teat end. This experiment highlights the importance of elevated mouthpiece

  4. Solvent fluctuations and nuclear quantum effects modulate the molecular hyperpolarizability of water

    Science.gov (United States)

    Liang, Chungwen; Tocci, Gabriele; Wilkins, David M.; Grisafi, Andrea; Roke, Sylvie; Ceriotti, Michele

    2017-07-01

    Second-harmonic scattering (SHS) experiments provide a unique approach to probe noncentrosymmetric environments in aqueous media, from bulk solutions to interfaces, living cells, and tissue. A central assumption made in analyzing SHS experiments is that each molecule scatters light according to a constant molecular hyperpolarizability tensor β(2 ). Here, we investigate the dependence of the molecular hyperpolarizability of water on its environment and internal geometric distortions, in order to test the hypothesis of constant β(2 ). We use quantum chemistry calculations of the hyperpolarizability of a molecule embedded in point-charge environments obtained from simulations of bulk water. We demonstrate that both the heterogeneity of the solvent configurations and the quantum mechanical fluctuations of the molecular geometry introduce large variations in the nonlinear optical response of water. This finding has the potential to change the way SHS experiments are interpreted: In particular, isotopic differences between H2O and D2O could explain recent SHS observations. Finally, we show that a machine-learning framework can predict accurately the fluctuations of the molecular hyperpolarizability. This model accounts for the microscopic inhomogeneity of the solvent and represents a step towards quantitative modeling of SHS experiments.

  5. Predicting groundwater level fluctuations with meteorological effect implications—A comparative study among soft computing techniques

    Science.gov (United States)

    Shiri, Jalal; Kisi, Ozgur; Yoon, Heesung; Lee, Kang-Kun; Hossein Nazemi, Amir

    2013-07-01

    The knowledge of groundwater table fluctuations is important in agricultural lands as well as in the studies related to groundwater utilization and management levels. This paper investigates the abilities of Gene Expression Programming (GEP), Adaptive Neuro-Fuzzy Inference System (ANFIS), Artificial Neural Networks (ANN) and Support Vector Machine (SVM) techniques for groundwater level forecasting in following day up to 7-day prediction intervals. Several input combinations comprising water table level, rainfall and evapotranspiration values from Hongcheon Well station (South Korea), covering a period of eight years (2001-2008) were used to develop and test the applied models. The data from the first six years were used for developing (training) the applied models and the last two years data were reserved for testing. A comparison was also made between the forecasts provided by these models and the Auto-Regressive Moving Average (ARMA) technique. Based on the comparisons, it was found that the GEP models could be employed successfully in forecasting water table level fluctuations up to 7 days beyond data records.

  6. Effect of electric fields and fluctuations on confinement in a bumpy torus

    International Nuclear Information System (INIS)

    Hiroe, S.; Glowienka, J.C.; Hillis, D.L.

    1986-06-01

    In order to understand the relationships between confinement and space potential (electric field) and between confinement and density fluctuations, plasma parameters in the ELMO Bumpy Torus Scale (EBT-S) have been measured systematically for a wide range of operating conditions. Present EBT plasma parameters do not show a strong dependence on the potential profile, but rather exhibit a correlation with the fluctuations. The plasma pressure profile is found to be consistent with the profile anticipated on the basis of the flute stability criterion for a marginally stable plasma. For a heating power of 100 kW, the stored energy density is found to be restricted to the range between 4.5 x 10 13 eV-cm -3 and 7 x 10 13 eV-cm -3 . The lower limit remains constant regardless of heating power and pertains to plasmas lacking an equilibrium and/or stability. The upper limit increases with heating power and is found to result from the onset of instabilities. In between the two limits is a plasma that is in an equilibrium state and is marginally stable. Operational trajectories exist that take the EBT plasma from one limit to the other

  7. Effects of Sulfurization Temperature on Properties of CZTS Films by Vacuum Evaporation and Sulfurization Method

    Directory of Open Access Journals (Sweden)

    Jie Zhang

    2013-01-01

    Full Text Available Copper zinc tin sulfur (CZTS thin films have been extensively studied in recent years for their advantages of low cost, high absorption coefficient (≥104 cm−1, appropriate band gap (~1.5 eV, and nontoxicity. CZTS thin films are promising materials of solar cells like copper indium gallium selenide (CIGS. In this work, CZTS thin films were prepared on glass substrates by vacuum evaporation and sulfurization method. Sn/Cu/ZnS (CZT precursors were deposited by thermal evaporation and then sulfurized in N2 + H2S atmosphere at temperatures of 360–560°C to produce polycrystalline CZTS thin films. It is found that there are some impurity phases in the thin films with the sulfurization temperature less than 500°C, and the crystallite size of CZTS is quite small. With the further increase of the sulfurization temperature, the obtained thin films exhibit preferred (112 orientation with larger crystallite size and higher density. When the sulfurization temperature is 500°C, the band gap energy, resistivity, carrier concentration, and mobility of the CZTS thin films are 1.49 eV, 9.37 Ω · cm, 1.714×1017 cm−3, and 3.89 cm2/(V · s, respectively. Therefore, the prepared CZTS thin films are suitable for absorbers of solar cells.

  8. Preservation Effect of Two-Stage Cinnamon Bark (Cinnamomum Burmanii) Oleoresin Microcapsules On Vacuum-Packed Ground Beef During Refrigerated Storage

    Science.gov (United States)

    Irfiana, D.; Utami, R.; Khasanah, L. U.; Manuhara, G. J.

    2017-04-01

    The purpose of this study was to determine the effect of two stage cinnamon bark oleoresin microcapsules (0%, 0.5% and 1%) on the TPC (Total Plate Count), TBA (thiobarbituric acid), pH, and RGB color (Red, Green, and Blue) of vacuum-packed ground beef during refrigerated storage (at 0, 4, 8, 12, and 16 days). This study showed that the addition of two stage cinnamon bark oleoresin microcapsules affected the quality of vacuum-packed ground beef during 16 days of refrigerated storage. The results showed that the TPC value of the vacuum-packed ground beef sample with the addition 0.5% and 1% microcapsules was lower than the value of control sample. The TPC value of the control sample, sample with additional 0.5% and 1% microcapsules were 5.94; 5.46; and 5.16 log CFU/g respectively. The TBA value of vacuum-packed ground beef were 0.055; 0.041; and 0.044 mg malonaldehyde/kg, resepectively on the 16th day of storage. The addition of two-stage cinnamon bark oleoresin microcapsules could inhibit the growth of microbia and decrease the oxidation process of vacuum-packed ground beef. Moreover, the change of vacuum-packed ground beef pH and RGB color with the addition 0.5% and 1% microcapsules were less than those of the control sample. The addition of 1% microcapsules showed the best effect in preserving the vacuum-packed ground beef.

  9. Effects of vacuum thermal cycling on mechanical and physical properties of high performance carbon/bismaleimide composite

    International Nuclear Information System (INIS)

    Yu Qi; Chen Ping; Gao Yu; Mu Jujie; Chen Yongwu; Lu Chun; Liu Dong

    2011-01-01

    Highlights: → The level of cross-links was improved to a certain extent. → The thermal stability was firstly improved and then decreased. → The transverse and longitudinal CTE were both determined by the degree of interfacial debonding. → The mass loss ratio increases firstly and then reaches a plateau value. → The surface morphology was altered and the surface roughness increased firstly and then decreased. → The transverse tensile strength was reduced. → The flexural strength increased firstly and then decreased to a plateau value. → The ILSS increased firstly and then decreased to a plateau value. - Abstract: The aim of this article was to investigate the effects of vacuum thermal cycling on mechanical and physical properties of high performance carbon/bismaleimide (BMI) composites used in aerospace. The changes in dynamic mechanical properties and thermal stability were characterized by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively. The changes in linear coefficient of thermal expansion (CTE) were measured in directions perpendicular and parallel to the fiber direction, respectively. The outgassing behavior of the composites were examined. The evolution of surface morphology and surface roughness were observed by atomic force microscopy (AFM). Changes in mechanical properties including transverse tensile strength, flexural strength and interlaminar shear strength (ILSS) were measured. The results indicated that the vacuum thermal cycling could improve the crosslinking degree and the thermal stability of resin matrix to a certain extent, and induce matrix outgassing and thermal stress, thereby leading to the mass loss and the interfacial debonding of the composite. The degradation in transverse tensile strength was caused by joint effects of the matrix outgassing and the interfacial debonding, while the changes in flexural strength and ILSS were affected by a competing effect between the crosslinking degree

  10. Zeta function methods and quantum fluctuations

    International Nuclear Information System (INIS)

    Elizalde, Emilio

    2008-01-01

    A review of some recent advances in zeta function techniques is given, in problems of pure mathematical nature but also as applied to the computation of quantum vacuum fluctuations in different field theories, and specially with a view to cosmological applications

  11. MEA vacuum system

    International Nuclear Information System (INIS)

    Stroo, R.; Schwebke, H.; Heine, E.

    1984-01-01

    This report describes construction and operation of the MEA vacuum system of NIKHEF (Netherlands). First, the klystron vacuum system, beam transport system, diode pump and a triode pump are described. Next, the isolation valve and the fast valves of the vacuum system are considered. Measuring instruments, vacuum system commands and messages of failures are treated in the last chapter. (G.J.P.)

  12. Vacuum system for ISABELLE

    International Nuclear Information System (INIS)

    Hobson, J.P.

    1975-01-01

    An analysis is presented of the proposed vacuum system for the planned ISABELLE storage rings with respect to acceptability and practicality from the vacuum viewport. A comparison is made between the proposed vacuum system and the vacuum system at the CERN ISR, and some comments on various design and operational parameters are made

  13. The effects of gusts on the fluctuating airloads of airfoils in transonic flow

    Science.gov (United States)

    Mccroskey, W. J.

    1984-01-01

    Unsteady interactions of distributed and sharp-edged gusts with a stationary airfoil have been analyzed in two-dimensional transonic flow.A simple method of introducing such disturbances has been numerically implemented within the framework of unsteady, transonic small-disturbance theory. Representative solutions for various airfoils subjected to chordwise and transverse gusts show that the strength and unsteady motion of the shock wave on the airfoil significantly affect the flowfield development and, consequently, the dynamic airloads. Also a study was made of the reductions in the unsteady airloads that can be achieved by the proper active control motion of a trailing-edge flap, and a simple gust-alleviation strategy was developed. However, the chordwise pressure distributions associated with gusts are very different from those produced by trailing-edge flap oscillations. Consequently, the fluctuating lift and the unsteady pitching moments cannot both be eliminated simultaneously.

  14. Opposing Effects of Intrinsic Conductance and Correlated Synaptic Input on V-Fluctuations during Network Activity

    DEFF Research Database (Denmark)

    Kolind, Jens; Hounsgaard, Jørn Dybkjær; Berg, Rune W

    2012-01-01

    Neurons often receive massive concurrent bombardment of synaptic inhibition and excitation during functional network activity. This increases membrane conductance and causes fluctuations in membrane potential (V(m)) and spike timing. The conductance increase is commonly attributed to synaptic....... If the spikes arrive at random times the changes in synaptic conductance are therefore stochastic and rapid during intense network activity. In comparison, sub-threshold intrinsic conductances vary smoothly in time. In the present study this discrepancy is investigated using two conductance-based models: a (1...... conductance, but also includes the intrinsic conductances recruited during network activity. These two sources of conductance have contrasting dynamic properties at sub-threshold membrane potentials. Synaptic transmitter gated conductance changes abruptly and briefly with each presynaptic action potential...

  15. Effect of periodic fluctuation of soil particle rotation resistance on interface shear behaviour

    International Nuclear Information System (INIS)

    Ebrahimian, Babak; Noorzad, Asadollah

    2010-01-01

    The interface behaviour between infinite extended narrow granular layer and bounding structure is numerically investigated using finite element method. The micro-polar (Cosserat) continuum approach within the framework of elasto-plasticity is employed to remove the numerical difficulties caused by strain-softening of materials in classical continuum mechanics. Mechanical properties of cohesionless granular soil are described with Lade's model enhanced with polar terms including Cosserat rotations, curvatures and couple stresses via mean grain diameter as the internal length. The main attention of paper is laid on the influence of spatial periodic fluctuation of rotation resistance of soil particles interlocked with the surface of bounding structure on evolution and location of shear band developed inside granular body. The finite element results demonstrate that the location and evolution of shear localization in granular body is strongly affected by prescribed non-uniform micro-polar kinematic boundary conditions along the interface.

  16. Spin fluctuation effects on the conductance through a single Pd atom contact

    International Nuclear Information System (INIS)

    Romero, M A; Goldberg, E C; Gomez-Carrillo, S C; Bolcatto, P G

    2009-01-01

    A controversy about the conductance through single atoms still exists. There are many experiments where values lower than the quantum unity G 0 = 2e 2 /h have been found associated to Kondo regimes with high Kondo temperatures. Specifically in the Pd single atom contact, conductance values close to G 0 /2 at room temperature have been reported. In this work we propose a theoretical analysis of a break junction of Pd where the charge fluctuation in the single atom contact is limited to the most probable one: d 10 ↔d 9 . The projected density of states and the characteristics of the electron transport are calculated by using a realistic description of the interacting system. A Kondo regime is found where the conductance values and their dependence on temperature are in good agreement with the experimental trends observed in the conduction of single molecule transistors based on transition metal coordination complexes.

  17. Effect of drying parameters on physiochemical and sensory properties of fruit powders processed by PGSS-, Vacuum- and Spray-drying.

    Science.gov (United States)

    Feguš, Urban; Žigon, Uroš; Petermann, Marcus; Knez, Željko

    2015-01-01

    Aim of this experimental work was to investigate the possibility of producing fruit powders without employing drying aid and to investigate the effect of drying temperatures on the final powder characteristics. Raw fruit materials (banana puree, strawberry puree and blueberry concentrate) were processed using three different drying techniques each operating at a different temperature conditions: vacuum-drying (-27-17 °C), Spray-drying (130-160 °C) and PGSS-drying (112-152 °C). Moisture content, total colour difference, antioxidant activity and sensory characteristics of the processed fruit powders were analysed. The results obtained from the experimental work indicate that investigated fruit powders without or with minimal addition of maltodextrin can be produced. Additionally, it was observed that an increase in process temperature results in a higher loss of colour, antioxidant activity and intensity of the flavour profile.

  18. Effect of Coil Current on the Properties of Hydrogenated DLC Coatings Fabricated by Filtered Cathodic Vacuum Arc Technique

    Science.gov (United States)

    Liao, Bin; Ouyang, Xiaoping; Zhang, Xu; Wu, Xianying; Bian, Baoan; Ying, Minju; Jianwu, Liu

    2018-01-01

    We successfully prepared hydrogenated DLC (a-C:H) with a thickness higher than 25 μm on stainless steel using a filtered cathode vacuum arc (FCVA) technique. The structural and mechanical properties of DLC were systematically analyzed using different methods such as x-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, Vickers hardness, nanohardness, and friction and wear tests. The effect of coil current on the arc voltage, ion current, and mechanical properties of resultant films was systematically investigated. The novelty of this study is the fabrication of DLC with Vickers hardness higher than 1500 HV, in the meanwhile with the thickness higher than 30 μm through varying the coil current with FCVA technique. The results indicated that the ion current, deposition rate, friction coefficient, and Vickers hardness of DLC were significantly affected by the magnetic field inside the filtered duct.

  19. The effect of substrate bias on titanium carbide/amorphous carbon nanocomposite films deposited by filtered cathodic vacuum arc

    International Nuclear Information System (INIS)

    Zhang, Xu; Liang, Hong; Wu, Zhenglong; Wu, Xiangying; Zhang, Huixing

    2013-01-01

    The titanium carbide/amorphous carbon nanocomposite films have been deposited on silicon substrate by filtered cathodic vacuum arc (FCVA) technology, the effects of substrate bias on composition, structures and mechanical properties of the films are studied by scanning electron spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy and nano-indentation. The results show that the Ti content, deposition rate and hardness at first increase and then decrease with increasing the substrate bias. Maximum hardness of the titanium carbide/amorphous carbon nanocomposite film is 51 Gpa prepared at −400 V. The hardness enhancement may be attributed to the compressive stress and the fraction of crystalline TiC phase due to ion bombardment

  20. Nonperturbative QED vacuum birefringence

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, V.I.; Dolgaya, E.E.; Sokolov, V.A. [Physics Department, Moscow State University,Moscow, 119991 (Russian Federation)

    2017-05-19

    In this paper we represent nonperturbative calculation for one-loop Quantum Electrodynamics (QED) vacuum birefringence in presence of strong magnetic field. The dispersion relations for electromagnetic wave propagating in strong magnetic field point to retention of vacuum birefringence even in case when the field strength greatly exceeds Sauter-Schwinger limit. This gives a possibility to extend some predictions of perturbative QED such as electromagnetic waves delay in pulsars neighbourhood or wave polarization state changing (tested in PVLAS) to arbitrary magnetic field values. Such expansion is especially important in astrophysics because magnetic fields of some pulsars and magnetars greatly exceed quantum magnetic field limit, so the estimates of perturbative QED effects in this case require clarification.

  1. Compact vacuum insulation embodiments

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1992-04-28

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point' or line' contacts with the metal wall sheets. In the case of monolithic spacers that form line' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included. 26 figs.

  2. Compact vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1993-01-05

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  3. [Effect of Transcutaneous Acupoint Electrical Stimulation on Hemodynamic Fluctuation Caused by Loosing Tourniquet in Elderly Patients Undergoing Knee Joint Replacement].

    Science.gov (United States)

    Liang, Han-Sheng; Feng, Yi

    2017-12-25

    To observe the effect of transcutaneous acupoint electrical stimulation (TAES) on hemodynamic fluctuation caused by loosing tourniquet in the elderly patients undergoing knee joint replacement. A total of 60 ASA (America Society Anesthesiologist) I or II elderly patients for elective knee joint replacement surgery were randomly divided into control group (30 cases) and TAES group (30 cases). Patients of both groups were treated by intravenous anesthesia, and monitored with bispectral index (BIS, between 45-60) for anesthesia depth, stroke volume variation (SVV) for fluid management, mean arterial pressure (MAP) and cardiac index (CI) for hemodynamic fluctuation evaluation, and with analgesia nociception index (ANI, between 50-70) for remifentanil dosage adjustment. TAES (2 Hz/100 Hz, 8-20 mA) was applied to bilateral Xinshu (BL 15), Feishu (BL 13), Neiguan (PC 6) and Hegu (LI 4) acupoints for 30 min first (followed by anesthesia induction and operation), and given continuously until 15 min after tourniquet loosing. Patients of the control group were only given with electrodes attachment without electrical stimulation. The levels of MAP, CI, and arterial blood pH, PaCO 2 , PaO 2 , base excess (BE) and lactic acid (Lac) 1 min before, and 5 and 15 min after tourniquet loosing, and the dosages of remifentanil and ephedrine after tourniquet loosing were recorded. The changed levels of MAP, CI and blood Lac at 5 min after tourniquet loosing (relevant to the baseline levels), and blood Lac content at 15 min after tourniquet loosing (relevant to 5 min after tourniquet loosing) were significantly lower in the TAES group than in the control group ( P 0.05). TAES has a positive effect on hemodynamics fluctuation caused by loosing tourniquet in the aged patients undergoing knee joint replacement.

  4. Effects of rf power on electron density and temperature, neutral temperature, and Te fluctuations in an inductively coupled plasma

    International Nuclear Information System (INIS)

    Camparo, James; Fathi, Gilda

    2009-01-01

    Atomic clocks that fly on global-navigation satellites such as global positioning system (GPS) and Galileo employ light from low-temperature, inductively coupled plasmas (ICPs) for atomic signal generation and detection (i.e., alkali/noble-gas rf-discharge lamps). In this application, the performance of the atomic clock and the capabilities of the navigation system depend sensitively on the stability of the ICP's optical emission. In order to better understand the mechanisms that might lead to instability in these rf-discharge lamps, and hence the satellite atomic clocks, we studied the optical emission from a Rb/Xe ICP as a function of the rf power driving the plasma. Surprisingly, we found that the electron density in the plasma was essentially independent of increases in rf power above its nominal value (i.e., 'rf-power gain') and that the electron temperature was only a slowly varying function of rf-power gain. The primary effect of rf power was to increase the temperature of the neutrals in the plasma, which was manifested by an increase in Rb vapor density. Interestingly, we also found evidence for electron temperature fluctuations (i.e., fluctuations in the plasma's high-energy electron content). The variance of these fluctuations scaled inversely with the plasma's mean electron temperature and was consistent with a simple model that assumed that the total electron density in the discharge was independent of rf power. Taken as a whole, our results indicate that the electrons in alkali/noble-gas ICPs are little affected by slight changes in rf power and that the primary effect of such changes is to heat the plasma's neutral species.

  5. Vacuum system for LHC

    International Nuclear Information System (INIS)

    Groebner, O.

    1995-01-01

    The Large Hadron Collider (LHC) which is planned at CERN will be housed in the tunnel of the Large Electron Positron collider (LEP) and will store two counter-rotating proton beams with energies of up to 7 TeV in a 27 km accelerator/storage ring with superconducting magnets. The vacuum system for the LHC will be at cryogenic temperatures (between 1.9 and 20 K) and will be exposed to synchrotron radiation emitted by the protons. A stringent limitation on the vacuum is given by the energy deposition in the superconducting coils of the magnets due to nuclear scattering of the protons on residual gas molecules because this may provoke a quench. This effect imposes an upper limit to a local region of increased gas density (e.g. a leak), while considerations of beam lifetime (100 h) will determine more stringent requirements on the average gas density. The proton beam creates ions from the residual gas which may strike the vacuum chamber with sufficient energy to lead to a pressure 'run-away' when the net ion induced desorption yield exceeds a stable limit. These dynamic pressure effects will be limited to an acceptable level by installing a perforated 'beam screen' which shields the cryopumped gas molecules at 1.9 K from synchrotron radiation and which also absorbs the synchrotron radiation power at a higher and, therefore, thermodynamically more efficient temperature. (author)

  6. Melting the vacuum

    International Nuclear Information System (INIS)

    Rafelski, J.

    1998-01-01

    Results presented at the Quark Matter 97 conference, held in December in Tsukuba, Japan, have provided new insights into the confinement of quarks in matter. The current physics paradigm is that the inertial masses of protons and neutrons, and hence of practically all of the matter around us, originate in the zero-point energy caused by the confinement of quarks inside the small volume of the nucleon. Today, 25 years after Harald Fritzsch, Heinrich Leutwyler and Murray Gell-Mann proposed quantum chromodynamics (QCD) as a means for understanding strongly interacting particles such as nucleons and mesons, our understanding of strong interactions and quark confinement remains incomplete. Quarks and the gluons that bind them together have a ''colour'' charge that may be red, green or blue. But quarks are seen in particles that are white: baryons such as protons and neutrons consist of three quarks with different colour charges, while mesons consist of a quark and an antiquark, and again the colour charge cancels out. To prove that confinement arises from quark-gluon fluctuations in the vacuum that quantum theories dictate exists today, we need to find a way of freeing the colour charge of quarks. Experiments must therefore ''melt'' the vacuum to deconfine quarks and the colour charge. By colliding nuclei at high energies, we hope to produce regions of space filled with free quarks and gluons. This deconfined phase is known as the quark-gluon plasma. At the Tsukuba meeting, Scott Pratt of Michigan State University in the US discussed measurements that show that the hot dense state of matter created in these collisions exists for only 2x10 -23 s. So does the quark gluon plasma exist? No-one doubts that it did at one time, before the vacuum froze into its current state about 20 into the life of the universe, causing the nucleons to form as we know them today. The issue is whether we can recreate this early stage of the universe in laboratory experiments. And if we did

  7. Ocean acidification reverses the positive effects of seawater pH fluctuations on growth and photosynthesis of the habitat-forming kelp, Ecklonia radiata.

    Science.gov (United States)

    Britton, Damon; Cornwall, Christopher E; Revill, Andrew T; Hurd, Catriona L; Johnson, Craig R

    2016-05-27

    Ocean acidification (OA) is the reduction in seawater pH due to the absorption of human-released CO2 by the world's oceans. The average surface oceanic pH is predicted to decline by 0.4 units by 2100. However, kelp metabolically modifies seawater pH via photosynthesis and respiration in some temperate coastal systems, resulting in daily pH fluctuations of up to ±0.45 units. It is unknown how these fluctuations in pH influence the growth and physiology of the kelp, or how this might change with OA. In laboratory experiments that mimicked the most extreme pH fluctuations measured within beds of the canopy-forming kelp Ecklonia radiata in Tasmania, the growth and photosynthetic rates of juvenile E. radiata were greater under fluctuating pH (8.4 in the day, 7.8 at night) than in static pH treatments (8.4, 8.1, 7.8). However, pH fluctuations had no effect on growth rates and a negative effect on photosynthesis when the mean pH of each treatment was reduced by 0.3 units. Currently, pH fluctuations have a positive effect on E. radiata but this effect could be reversed in the future under OA, which is likely to impact the future ecological dynamics and productivity of habitats dominated by E. radiata.

  8. The Effect of Tic Coated Balls and Stress on the Lubricant Lifetime of a Synthetic Hydrocarbon (pennzane 2001A) Using a Vacuum Spiral Orbit Tribometer

    Science.gov (United States)

    Jansen, Mark J.; Jones, William R., Jr.; Pepper, Stephen V.; Wheeler, Donald R.; Schroeer, Achim; Fluehmann, Freddy; Loewenthal, Stuart H.; Shogrin, Bradley A.

    2000-01-01

    A vacuum spiral orbit rolling contact tribometer was used to determine effect of varying mean Hertzian stress (1.0, 1.5, 2.0 GPa) and the use of 440C and TiC coated 440C balls on lubricant lifetime of a synthetic hydrocarbon (Pennzane 2001A) on 440C stainless steel. Conditions included 210 rpm, approx. 50 micrograms lubricant, an initial vacuum TiC coated 440C ball showed no increase in lifetime over the 440C ball. The decreasing lifetime with increasing stress level correlated well with energy dissipation calculations.

  9. Potential Fluctuations and Localization Effects in CZTS Single Crystals, as Revealed by Optical Spectroscopy

    Science.gov (United States)

    Bleuse, Joël; Ducroquet, Frédérique; Mariette, Henri

    2018-03-01

    Reports on Cu_2 ZnSn(S_x Se_{1-x} )_4 (CZTSSe) solar cell devices all show an open-circuit voltage lower than expected, especially when compared to CuIn_x Ga_{1-x} (S,Se)_2 devices, which reduces their power efficiency and delays their development. A high concentration of intrinsic defects in CZTSSe, and their stabilization through neutral complex formation, which induces some local fluctuations, are at the origin of local energy shifts in the conduction and valence band edges. The implied band tail in Cu_2 ZnSnS_4 is studied in this work by combining three types of optical spectroscopy data: emission spectra compared to photoluminescence excitation spectroscopy, emission spectra as a function of excitation power, and time-resolved photoluminescence spectra. All these data converge to show that both the bandgap and the band tail of localized states just below are dependent on the degree of order/disorder in the Cu/Zn cation sublattice of the quaternary structure: in the more ordered structures, the bandgap increases by about 50 meV, and the energy range of the band tail is decreased from about 110 to 70 meV.

  10. Effect of pedestal fluctuation on ELM frequency in the EAST tokamak

    Science.gov (United States)

    Zhong, F. B.; Zhang, T.; Liu, Z. X.; Qu, H.; Liu, H. Q.; Li, G. Q.; Liu, Y.; Gao, W.; Duan, Y. M.; Yang, Y.; Zeng, L.; Xiang, H. M.; Geng, K. N.; Wen, F.; Zhang, S. B.; Gao, X.; the EAST Team

    2018-05-01

    The dependence of ELM frequency on heating power has been studied on the Experimental Advanced Superconducting Tokamak (EAST). It is found that the ELM frequency (f ELM) generally increases with the power through separatrix (P sep), indicating type-I ELM in these plasmas. However, there are two data points, named ‘abnormal ELM’ in the present paper, which have much lower f ELM than the ‘normal ELM’, while both types of ELM have similar ELM energy losses. The ‘abnormal ELM’ occurs at a phase with increased radiation power due to metal impurity influx events. The increased radiation power cannot explain the much lower f ELM for ‘abnormal ELM’, since the reduction of P sep is weaker than proportional to the observed reduction of the ELM frequency. The ‘abnormal ELM’ feature can be attributed to the enhanced amplitude of a coherent mode in the pedestal region. Comparing the pedestal evolutions for the two types of ELM with similar separatrix power P sep, it is actually found that the more pronounced pedestal coherent mode in the plasma with ‘abnormal ELM’ leads to a slower pressure pedestal recovery during the inter-ELM phase. This experimental result implies that the physical mechanism for ‘abnormal ELM’ is that the more pronounced pedestal fluctuation induces larger outward transport, slows down the pedestal evolution and leads to longer inter-ELM phase, i.e. lower ELM frequency.

  11. Charge Fluctuations in Nanoscale Capacitors

    NARCIS (Netherlands)

    Limmer, D.T.; Merlet, C.; Salanne, M.; Chandler, D.; Madden, P.A.; van Roij, R.H.H.G.; Rotenberg, B.

    2013-01-01

    The fluctuations of the charge on an electrode contain information on the microscopic correlations within the adjacent fluid and their effect on the electronic properties of the interface. We investigate these fluctuations using molecular dynamics simulations in a constant-potential ensemble with

  12. True random numbers from amplified quantum vacuum.

    Science.gov (United States)

    Jofre, M; Curty, M; Steinlechner, F; Anzolin, G; Torres, J P; Mitchell, M W; Pruneri, V

    2011-10-10

    Random numbers are essential for applications ranging from secure communications to numerical simulation and quantitative finance. Algorithms can rapidly produce pseudo-random outcomes, series of numbers that mimic most properties of true random numbers while quantum random number generators (QRNGs) exploit intrinsic quantum randomness to produce true random numbers. Single-photon QRNGs are conceptually simple but produce few random bits per detection. In contrast, vacuum fluctuations are a vast resource for QRNGs: they are broad-band and thus can encode many random bits per second. Direct recording of vacuum fluctuations is possible, but requires shot-noise-limited detectors, at the cost of bandwidth. We demonstrate efficient conversion of vacuum fluctuations to true random bits using optical amplification of vacuum and interferometry. Using commercially-available optical components we demonstrate a QRNG at a bit rate of 1.11 Gbps. The proposed scheme has the potential to be extended to 10 Gbps and even up to 100 Gbps by taking advantage of high speed modulation sources and detectors for optical fiber telecommunication devices.

  13. The fluctuating gap model

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Xiaobin

    2011-01-15

    The quasi-one-dimensional systems exhibit some unusual phenomenon, such as the Peierls instability, the pseudogap phenomena and the absence of a Fermi-Dirac distribution function line shape in the photoemission spectroscopy. Ever since the discovery of materials with highly anisotropic properties, it has been recognized that fluctuations play an important role above the three-dimensional phase transition. This regime where the precursor fluctuations are presented can be described by the so called fluctuating gap model (FGM) which was derived from the Froehlich Hamiltonian to study the low energy physics of the one-dimensional electron-phonon system. Not only is the FGM of great interest in the context of quasi-one-dimensional materials, liquid metal and spin waves above T{sub c} in ferromagnets, but also in the semiclassical approximation of superconductivity, it is possible to replace the original three-dimensional problem by a directional average over effectively one-dimensional problem which in the weak coupling limit is described by the FGM. In this work, we investigate the FGM in a wide temperature range with different statistics of the order parameter fluctuations. We derive a formally exact solution to this problem and calculate the density of states, the spectral function and the optical conductivity. In our calculation, we show that a Dyson singularity appears in the low energy density of states for Gaussian fluctuations in the commensurate case. In the incommensurate case, there is no such kind of singularity, and the zero frequency density of states varies differently as a function of the correlation lengths for different statistics of the order parameter fluctuations. Using the density of states we calculated with non-Gaussian order parameter fluctuations, we are able to calculate the static spin susceptibility which agrees with the experimental data very well. In the calculation of the spectral functions, we show that as the correlation increases, the

  14. The fluctuating gap model

    International Nuclear Information System (INIS)

    Cao, Xiaobin

    2011-01-01

    The quasi-one-dimensional systems exhibit some unusual phenomenon, such as the Peierls instability, the pseudogap phenomena and the absence of a Fermi-Dirac distribution function line shape in the photoemission spectroscopy. Ever since the discovery of materials with highly anisotropic properties, it has been recognized that fluctuations play an important role above the three-dimensional phase transition. This regime where the precursor fluctuations are presented can be described by the so called fluctuating gap model (FGM) which was derived from the Froehlich Hamiltonian to study the low energy physics of the one-dimensional electron-phonon system. Not only is the FGM of great interest in the context of quasi-one-dimensional materials, liquid metal and spin waves above T c in ferromagnets, but also in the semiclassical approximation of superconductivity, it is possible to replace the original three-dimensional problem by a directional average over effectively one-dimensional problem which in the weak coupling limit is described by the FGM. In this work, we investigate the FGM in a wide temperature range with different statistics of the order parameter fluctuations. We derive a formally exact solution to this problem and calculate the density of states, the spectral function and the optical conductivity. In our calculation, we show that a Dyson singularity appears in the low energy density of states for Gaussian fluctuations in the commensurate case. In the incommensurate case, there is no such kind of singularity, and the zero frequency density of states varies differently as a function of the correlation lengths for different statistics of the order parameter fluctuations. Using the density of states we calculated with non-Gaussian order parameter fluctuations, we are able to calculate the static spin susceptibility which agrees with the experimental data very well. In the calculation of the spectral functions, we show that as the correlation increases, the quasi

  15. The effect of vacuum assisted socket suspension on prospective, community-based falls by users of lower limb prostheses.

    Science.gov (United States)

    Rosenblatt, Noah J; Ehrhardt, Tess

    2017-06-01

    Individuals with lower limb amputation are at increased risk of falling compared to age-matched peers. The purpose of this study was to quantify the effect of socket suspension on the risk of falling, by comparing prospectively tracked falls between a group of participants that used vacuum assisted socket suspension (VASS) and a group that did not use this system. Fifteen current users of VASS and 12 non-VASS users received an email every two weeks for one year, with a link to an online survey that asked whether they fell (i.e., "unintentionally came to rest on a lower surface") or stumbled (i.e., lost balance but did not fall) in the prior two weeks. A Chi-squared test was used to compare fall and stumble risk between groups, after stratifying by level of amputation, and the phi coefficient (φ) was used to quantify effect size. While the use of VASS did not affect the rate of falling (i.e., falls per person year) for either persons with transtibial amputation (TTA) or those with transfemoral amputation (TFA), the absolute risk of having multiple falls was reduced by nearly 75% in the former (φ=0.83), which is particularly important given that recurrent falls are associated with more severe injuries. There was no effect of VASS on the risk of falls in TFA. Further work is warranted to demonstrate the persistence of these effects in larger, more controlled samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Experimental study on high cycle thermal fatigue in T-junction. Effect of local flow velocity on transfer of temperature fluctuation from fluid to structure

    International Nuclear Information System (INIS)

    Kimura, Nobuyuki; Ono, Ayako; Miyakoshi, Hiroyuki; Kamide, Hideki

    2009-01-01

    A quantitative evaluation on high cycle thermal fatigue due to temperature fluctuation in fluid is of importance for structural integrity in the reactor. It is necessary for the quantitative evaluation to investigate occurrence and propagation processes of temperature fluctuation, e.g., decay of fluctuation intensity near structures and transfer of temperature fluctuation from fluid to structures. The JSME published a guideline for evaluation of high-cycle thermal fatigue of a pipe as the JSME guideline in 2003. This JSME standard covers T-pipe junction used in LWRs operated in Japan. In the guideline, the effective heat transfer coefficients were obtained from temperature fluctuations in fluid and structure in experiments. In the previous studies, the effective heat transfer coefficients were 2 - 10 times larger than the heat transfer coefficients under steady state conditions in a straight tube. In this study, a water experiment of T-junction was performed to evaluate the transfer characteristics of temperature fluctuation from fluid to structure. In the experiment, temperatures in fluid and structure were measured simultaneously at 20 positions to obtain spatial distributions of the effective heat transfer coefficient. In addition, temperatures in structure and local velocities in fluid were measured simultaneously to evaluate the correlation between the temperature and velocity under the non-stationary fields. The large heat transfer coefficients were registered at the region where the local velocity was high. Furthermore it was found that the heat transfer coefficients were correlated with the time-averaged turbulent heat flux near the pipe wall. (author)

  17. The effect of the operation modes of a gas discharge low-pressure amalgam lamp on the intensity of generation of 185 nm UV vacuum radiation

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyak, L. M., E-mail: vasilyak@ihed.ras.ru [Russian Academy of Sciences, Joint Institute of High Temperatures (Russian Federation); Drozdov, L. A., E-mail: lit@npo.lit.ru; Kostyuchenko, S. V.; Sokolov, D. V. [ZAO LIT (Russian Federation); Kudryavtsev, N. N.; Sobur, D. A., E-mail: soburda@gmail.com [Moscow Institute for Physics and Technology (Russian Federation)

    2011-12-15

    The effect of the discharge current, mercury vapor pressure, and the inert gas pressure on the intensity and efficiency of the 185 nm line generation are considered. The spectra of the UV radiation (vacuum ultraviolet) transmission by protective coatings from the oxides of rare earth metals and aluminum are investigated.

  18. Catalytic effects of various catalysts in hydroprocessing of Cold Lake vacuum bottom. Cold Lake zansayu no hydroprocessing ni okeru kakushu shokubai no koka

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, S.; Yamamoto, M.; Maekawa, Y.; Kotanigawa, T. (Government Industrial Development Laboratory, Hokkaido, Sapporo (Japan))

    1991-11-07

    The effects of various types of catalysts were studied on hydroprocessing of Cold Lake vacuum bottom (CLVB). FeS2 [Py] of an analytical reagent grade was used as sulfide catalyst, Fe2O3(SO4)[sup 2[minus

  19. Experimental and theoretical analysis of vacuum circuit breaker prestrike effect on a transformer, Calgary Alberta, Canada 29-31 July 2009

    NARCIS (Netherlands)

    Popov, M.; Smeets, R.P.P.; Sluis, van der L.; Herdt, de H.; Declercq, J.

    2009-01-01

    Summary form only given. The work presented in this paper deals with the investigation of circuit breaker prestrike effect that occurs during energizing a distribution transformer. An experimental test setup that consists of a supply transformer, a vacuum circuit breaker (VCB), a cable and a test

  20. CAS CERN Accelerator School vacuum technology. Proceedings

    International Nuclear Information System (INIS)

    Turner, S.

    1999-01-01

    These proceedings present the lectures given at the twelfth specialized course organized by the CERN Accelerator School (CAS), the topic this time being 'Vacuum Technology'. Despite the importance of vacuum technology in the design and operation of particle accelerators at CERN and at the many other accelerators already installed around the world, this was the first time that CAS has organized a course devoted entirely to this topic. Perhaps this reflects the facts that vacuum has become one of the more critical aspects of future accelerators, and that many of the pioneers in the accelerator field are being replaced by new, younger personnel. The lectures start with the basic concepts of the physics and technology of vacuum followed by detailed descriptions of the many different types of gas-pumping devices and methods to measure the pressures achieved. The outgassing characteristics of the different materials used in the construction of vacuum systems and the optimisation of cleaning methods to reduce this outgassing are then explained together with the effects of the residual gases on the particle beams. Then follow chapters on leak detection, materials and vacuum system engineering. Finally, seminars are presented on designing vacuum systems, the history of vacuum devices, the LHC (large hadron collider) vacuum system, vacuum systems for electron storage rings, and quality assurance for vacuum. (orig.)

  1. Effect of operating methods of wind turbine generator system on net power extraction under wind velocity fluctuations in fields

    Energy Technology Data Exchange (ETDEWEB)

    Wakui, Tetsuya; Yamaguchi, Kazuya; Hashizume, Takumi [Waseda Univ., Advanced Research Inst. for Science and Engineering, Tokyo (Japan); Outa, Eisuke [Waseda Univ., Mechanical Engineering Dept., Tokyo (Japan); Tanzawa, Yoshiaki [Nippon Inst. of Technology, Mechanical Engineering Dept., Saitama (Japan)

    1999-01-01

    The effect of how a wind turbine generator system is operated is discussed from the viewpoint of net power extraction with wind velocity fluctuation in relation to the scale and the dynamic behaviour of the system. On a wind turbine generator system consisting of a Darrieus-Savonius hybrid wind turbine, a load generator and a battery, we took up two operating methods: constant tip speed ratio operation for a stand-alone system (Scheme 1) and synchronous operation by connecting a grid (Scheme 2). With our simulation model, using the result of the net extracting power, we clarified that Scheme 1 is more effective than Scheme 2 for small-scale systems. Furthermore, in Scheme 1, the appropriate rated power output of the system under each wind condition can be confirmed. (Author)

  2. Drying behaviour, effective diffusivity and energy of activation of olive leaves dried by microwave, vacuum and oven drying methods

    Science.gov (United States)

    Elhussein, Elaf Abdelillah Ali; Şahin, Selin

    2018-01-01

    Drying is the crucial food processing for bioactive components from plant materials before strating extraction in addition to preservation of raw plant materials during storage period. Olive leaves were dried by various methods such as microwave drying (MD), oven drying (OD) and vacuum drying (VD) at several temperature values in the present study. Mathematical models allow to develop, design and control the processes. 14 emprical equations were used to estimate the drying behaviour and the time required for drying. Convenience of the models were evaluated according to the correlation coefficient (R 2 ), varience (S 2 ) and root mean square deviation (D RMS ). On the other hand, the effective diffusion coefficient and energy for activation were also calculated. Effects of the drying methods on the total phenolic (TPC), flavonoid (TFC) and oleuropein contents and free radical scavenging activity (FRSA) of the olive leaves were also investigated to take into considiration the quality of the dried product. MD has proved to be the fastest drying method having the highest effective diffusivity and the lowest activation energy with a more qualitive product.

  3. Effect of low-dose (1 kGy) gamma radiation and selected phosphates on the microflora of vacuum-packaged ground pork

    International Nuclear Information System (INIS)

    Ehioba, R.M.

    1987-01-01

    The effects of low-dose (1 kGy) gamma radiation and selected phosphates on the microbiology of refrigerated, vacuum-packaged ground pork were studied. Low-dose gamma radiation reduced the numbers of naturally occurring mesophiles, psychrotrophs, and anaerobes. The effect of low-dose radiation on the populations of lactic acid bacteria was minimal. On storage of the irradiated vacuum-packaged ground pork at 5 0 C, there was a partial bacterial recovery, suggesting sublethal bacterial injury due to irradiation. When 10 7 CFU/g of meat is taken to be the level beyond which the meat would be considered spoiled, uninoculated, vacuum-packaged ground pork treated with 1 kGy (100 krad) of gamma radiation had 3.5 more days of shelf-life in terms of psychrotrophic total counts. In relation to anaerobic bacterial numbers, meat shelf-life was extended 2.5 days, while the shelf-life of meat was extended 1 day in terms of aerobic mesophilic bacteria. Irradiation prolonged shelf-life in inoculated (10 5 CFU/g) meat for 1.0-1.5 days. Addition of 0.4% sodium acid pyrophosphate (SAPP) contributed 2 additional days to inoculated, irradiated vacuum-packaged ground pork shelf-life. However, SAPP had no added effect on naturally occurring microflora. Irradiation greatly decreased the numbers of gram-negative microorganisms, resulting in predominance of the gram-positive, nonsporeforming Lactobacillus and coryneform bacteria

  4. Effects of filtered cathodic vacuum arc deposition (FCVAD) conditions on photovoltaic TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Aramwit, C. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Intarasiri, S. [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Bootkul, D. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Department of General Science, Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Tippawan, U. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Supsermpol, B.; Seanphinit, N. [Department of General Science, Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Western Digital Thailand Co. Ltd., Ayutthaya 13160 (Thailand); Ruangkul, W. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2014-08-15

    Highlights: • Titanium dioxide films were synthesized using the FCVAD technique. • Various FCVAD conditions were tested. • The TiO{sub 2} films were characterized. • The FCVAD condition effects on the film characteristics were studied. • The O{sub 2} pressure had the most important effect on the film quality. - Abstract: Titanium dioxide (TiO{sub 2}) films for photovoltaic applications were synthesized using filtered cathodic vacuum arc deposition (FCVAD) technique. Various deposition conditions were tested for an optimal film formation. The conditions included the oxygen (O{sub 2}) pressure which was varied from a base pressure 10{sup −5} to 10{sup −4}, 10{sup −3}, 10{sup −2} and 10{sup −1} Torr, sample holder bias varied using 0 or −250 V, deposition time varied from 10, 20 to 30 min, and deposition distance varied from 1 to 3 cm. The deposited films were also annealed and compared with unannealed ones. The films under various conditions were characterized using optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS) and Raman spectroscopy techniques. The film transparency increased and thickness decreased to a nanoscale with increasing of the O{sub 2} pressure. The transparent deposited films contained stoichiometric titanium and oxygen under the medium O{sub 2} pressure. The as-deposited films were TiO{sub 2} containing some rutile but no anatase which needed annealing to form.

  5. Vacuum-assisted delivery

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000514.htm Vacuum-assisted delivery To use the sharing features on this page, ... through the birth canal. When is Vacuum-assisted Delivery Needed? Even after your cervix is fully dilated ( ...

  6. The Effect of Vacuum Annealing of Magnetite and Zero-Valent Iron Nanoparticles on the Removal of Aqueous Uranium

    Directory of Open Access Journals (Sweden)

    R. A. Crane

    2013-01-01

    Full Text Available As-formed and vacuum annealed zero-valent iron nanoparticles (nano-Fe0 and magnetite nanoparticles (nano-Fe3O4 were tested for the removal of uranium from carbonate-rich mine water. Nanoparticles were introduced to batch systems containing the mine water under oxygen conditions representative of near-surface waters, with a uranyl solution studied as a simple comparator system. Despite the vacuum annealed nano-Fe0 having a 64.6% lower surface area than the standard nano-Fe0, similar U removal (>98% was recorded during the initial stages of reaction with the mine water. In contrast, ≤15% U removal was recorded for the mine water treated with both as-formed and vacuum annealed nano-Fe3O4. Over extended reaction periods (>1 week, appreciable U rerelease was recorded for the mine water solutions treated using nano-Fe0, whilst the vacuum annealed material maintained U at <50 μg L−1 until 4 weeks reaction. XPS analysis of reacted nanoparticulate solids confirmed the partial chemical reduction of UVI to UIV in both nano-Fe0 water treatment systems, but with a greater amount of UIV detected on the vacuum annealed particles. Results suggest that vacuum annealing can enhance the aqueous reactivity of nano-Fe0 and, for waters of complex chemistry, can improve the longevity of aqueous U removal.

  7. Vacuum friction

    Science.gov (United States)

    Barnett, Stephen M.; Sonnleitner, Matthias

    2018-03-01

    We know that in empty space there is no preferred state of rest. This is true both in special relativity but also in Newtonian mechanics with its associated Galilean relativity. It comes as something of a surprise, therefore, to discover the existence a friction force associated with spontaneous emission. The resolution of this paradox relies on a central idea from special relativity even though our derivation of it is non-relativistic. We examine the possibility that the physics underlying this effect might be explored in an ion trap, via the observation of a superposition of different mass states.

  8. Fluctuations in quantum chaos

    International Nuclear Information System (INIS)

    Casati, G.; Chirikov, B.V.

    1996-01-01

    Various fluctuations in quantum systems with discrete spectrum are discussed, including recent unpublished results. Open questions and unexplained peculiarities of quantum fluctuations are formulated [ru

  9. Excess hall effect in epitaxial YBCO film under moderate magnetic fields, approached by renormalized superconducting fluctuations model

    International Nuclear Information System (INIS)

    Puica, I.; Lang, W.; Goeb, W.; Sobolewski, R.

    2002-01-01

    Full text: Measurements of the Hall effect and the resistivity on precisely-patterned YBCO thin film in moderate magnetic fields B from 0.5 to 6 T oriented parallel to the crystallographic c axis reveal a sign reversal of the Hall coefficient for B < 3 T. The data are confronted with the full quantitative expressions given by the renormalized fluctuation model for the excess Hall conductivity. The model offers a satisfactory quantitative approach to the experimental results, for moderate fields and temperatures near the critical region, provided the inhomogeneity of the critical temperature distribution is also taken into account. For lower fields and temperatures, the adequacy of the model is altered by vortex pinning. (author)

  10. {mu}SR study of organic systems: ferromagnetism, antiferromagnetism, the spin-crossover effect, and fluctuations in magnetic nanodiscs

    Energy Technology Data Exchange (ETDEWEB)

    Blundell, S.J.; Pratt, F.L.; Lancaster, T.; Marshall, I.M.; Steer, C.A.; Hayes, W.; Sugano, T.; Letard, J.-F.; Caneschi, A.; Gatteschi, D.; Heath, S.L

    2003-02-01

    We present the results of recent {mu}SR experiments on a variety of novel organic and molecular magnetic systems. Muons are sensitive to local static fields and magnetic fluctuations, but can probe much more than just the onset of long-range magnetic order. We review our work on nitronyl nitroxide organic ferromagnets and antiferromagnets. We describe a muon study of the spin-crossover phenomenon which has been studied in Fe(PM-PEA){sub 2}(NCS){sub 2}, and which shows Gaussian and root-exponential muon relaxation in the high-spin and low-spin phases, respectively. Experiments on a disc-shaped molecular complex containing Fe{sub 19} (with spin ((31)/(2))) reveal the effects of quantum tunneling of magnetization and allow an estimate of the quantum tunneling rate.

  11. μSR study of organic systems: ferromagnetism, antiferromagnetism, the spin-crossover effect, and fluctuations in magnetic nanodiscs

    International Nuclear Information System (INIS)

    Blundell, S.J.; Pratt, F.L.; Lancaster, T.; Marshall, I.M.; Steer, C.A.; Hayes, W.; Sugano, T.; Letard, J.-F.; Caneschi, A.; Gatteschi, D.; Heath, S.L.

    2003-01-01

    We present the results of recent μSR experiments on a variety of novel organic and molecular magnetic systems. Muons are sensitive to local static fields and magnetic fluctuations, but can probe much more than just the onset of long-range magnetic order. We review our work on nitronyl nitroxide organic ferromagnets and antiferromagnets. We describe a muon study of the spin-crossover phenomenon which has been studied in Fe(PM-PEA) 2 (NCS) 2 , and which shows Gaussian and root-exponential muon relaxation in the high-spin and low-spin phases, respectively. Experiments on a disc-shaped molecular complex containing Fe 19 (with spin ((31)/(2))) reveal the effects of quantum tunneling of magnetization and allow an estimate of the quantum tunneling rate

  12. Effects of oral glucose load on endothelial function and on insulin and glucose fluctuations in healthy individuals

    DEFF Research Database (Denmark)

    Major-Pedersen, A; Ihlemann, N; Hermann, T S

    2008-01-01

    to better understand and cope with the postprandial state in insulin resistant individuals. METHODS: We assessed post-oral glucose load endothelial function (flow mediated dilation), plasma insulin, and blood glucose in 9 healthy subjects. RESULTS: The largest increases in delta FMD values (fasting FMD......BACKGROUND/AIMS: Postprandial hyperglycemia, an independent risk factor for cardiovascular disease, is accompanied by endothelial dysfunction. We studied the effect of oral glucose load on insulin and glucose fluctuations, and on postprandial endothelial function in healthy individuals in order...... value subtracted from postprandial FMD value) occurred at 3 hours after both glucose or placebo load, respectively: 4.80 +/- 1.41 (P = .009) and 2.34 +/- 1.47 (P = .15). Glucose and insulin concentrations achieved maximum peaks at one hour post-glucose load. CONCLUSION: Oral glucose load does not induce...

  13. Effect of spin fluctuations in magnetocaloric and magnetoresistance properties of Dy10Co20Si70 alloy

    Science.gov (United States)

    Rashid, T. P.; Arun, K.; Curlik, Ivan; Ilkovic, Sergej; Reiffers, Marian; Dzubinska, Andrea; Nagalakshmi, R.

    2017-09-01

    Systematic investigations on the structure, magnetic, thermodynamic, magnetocaloric and magnetoresistance (MR) properties of the arc melted Dy10Co20Si70 alloy are presented. The Dy10Co20Si70 alloy crystallizes in tetragonal BaNiSn3-type DyCoSi3 (space group = I4mm; No. 107) as a major phase and CaF2-type CoSi2 (space group = Fm-3m; No. 225) and C-type Si (space group = Fd-3m; No. 227) as minor phases. The title compound exhibits multiple magnetic transitions having antiferromagnetic ordering at temperatures, viz., T1 = 10.8 K, T2 = 8.8 K and T3 = 3.3 K. The magnetic and thermodynamic studies confirm these magnetic anomalies in the compound. The large value of maximum magnetic entropy change, -ΔSMM a x = 16.4 and 26.6 J/kg K for the field change ΔH of 50 and 90 kOe, respectively, observed in the compound is associated with field induced magnetic transitions. Asymmetric broadening of the magnetic entropy change peaks above the ordering temperatures resulting in significant refrigerant capacities of 361 and 868 J/kg for ΔH = 50 and 90 kOe, respectively, in the compound is due to the spin fluctuation effect. The sign reversal in MR measurements is attributed to the field induced antiferromagnetic to ferromagnetic transition. A large positive MR (42% in 90 kOe) is observed at 2 K. The H2 dependence of both the magnetocaloric effect (MCE) and MR in the paramagnetic regime indicates the role of the applied magnetic field in suppressing the spin fluctuations. The large MCE and MR together with no thermal or magnetic hysteresis establish this new compound as an attractive multifunctional magnetic material.

  14. Integrated cooling-vacuum-assisted 1540-nm erbium:glass laser is effective in treating mild-to-moderate acne vulgaris.

    Science.gov (United States)

    Politi, Y; Levi, A; Enk, C D; Lapidoth, M

    2015-12-01

    Acne treatment by a mid-infrared laser may be unsatisfactory due to deeply situated acne-affected sebaceous glands which serve as its target. Skin manipulation by vacuum and contact cooling may improve laser-skin interaction, reduce pain sensation, and increase overall safety and efficacy. To evaluate the safety and efficacy of acne treatment using an integrated cooling-vacuum-assisted 1540-nm erbium:glass laser, a prospective interventional study was conducted. It included 12 patients (seven men and five women) suffering from mild-to-moderate acne vulgaris. The device utilizes a mid-infrared 1540-nm laser (Alma Lasers Ltd. Caesarea, Israel), which is integrated with combined cooling-vacuum-assisted technology. An acne lesion is initially manipulated upon contact by a vacuum-cooling-assisted tip, followed by three to four stacked laser pulses (500-600 mJ, 4 mm spot size, and frequency of 2 Hz). Patients underwent four to six treatment sessions with a 2-week interval and were followed-up 1 and 3 months after the last treatment. Clinical photographs were taken by high-resolution digital camera before and after treatment. Clinical evaluation was performed by two independent dermatologists, and results were graded on a scale of 0 (exacerbation) to 4 (76-100 % improvement). Patients' and physicians' satisfaction was also recorded. Pain perception and adverse effects were evaluated as well. All patients demonstrated a moderate to significant improvement (average score of 3.6 and 2.0 within 1 and 3 months, respectively, following last treatment session). No side effects, besides a transient erythema, were observed. Cooling-vacuum-assisted 1540-nm laser is safe and effective for the treatment of acne vulgaris.

  15. Coherently enhanced radiation reaction effects in laser-vacuum acceleration of electron bunches

    NARCIS (Netherlands)

    Smorenburg, P.W.; Kamp, L.P.J.; Geloni, G.; Luiten, O.J.

    2010-01-01

    The effects of coherently enhanced radiation reaction on the motion of subwavelength electron bunches in interaction with intense laser pulses are analyzed. The radiation reaction force behaves as a radiation pressure in the laser beam direction, combined with a viscous force in the perpendicular

  16. Innovative Design of Solar-Powered Desalination (SPD System using Vacuum-Multi Effect Membrane Distillation (V-MEMD Process

    Directory of Open Access Journals (Sweden)

    Chafidz Achmad

    2018-01-01

    Full Text Available This research focused on the development of an innovative design of solar-powered desalination (SPD system which was expected to solve the water and energy problem simultaneously. We have developed a portable and hybrid solar-powered desalination (SPD system for producing potable water from saline water. It is a self-contained and integrated system which combines solar-thermal collector and solar-photovoltaic for its operation, and thus the system can operate to produce water by only using solar energy. Therefore, the system is highly suitable to be implemented in remote arid and coastal areas without infrastructures or connection to the grid (water and power, but blessed with abundant solar irradiation, like in Saudi Arabia. A Memsys Vacuum Multi-Effect Membrane Distillation (V-MEMD unit was used as the core of the SPD system. A heat pump was also integrated into the SPD system for energy recovery and to improve the performance of the system. The system could be considered as sustainable and “green” desalination technology, which will be very useful for the Kingdom of Saudi Arabia. To study the performance of the system, small-scale tests have been carried out at the Engineering College - King Saud University, Saudi Arabia. Based on the experimental results, the system has run successfully by only utilizing solar energy.

  17. Effects of vacuum-ultraviolet irradiation on copper penetration into low-k dielectrics under bias-temperature stress

    Energy Technology Data Exchange (ETDEWEB)

    Guo, X.; Zheng, H.; Xue, P.; Shohet, J. L. [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); King, S. W. [Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States); Nishi, Y. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2015-01-05

    The effects of vacuum-ultraviolet (VUV) irradiation on copper penetration into non-porous low-k dielectrics under bias-temperature stress (BTS) were investigated. By employing x-ray photoelectron spectroscopy depth-profile measurements on both as-deposited and VUV-irradiated SiCOH/Cu stacks, it was found that under the same BTS conditions, the diffusion depth of Cu into the VUV-irradiated SiCOH is higher than that of as-deposited SiCOH. On the other hand, under the same temperature-annealing stress (TS) without electric bias, the Cu distribution profiles in the VUV-irradiated SiCOH were same with that for the as-deposited SiCOH. The experiments suggest that in as-deposited SiCOH, the diffused Cu exists primarily in the atomic state, while in VUV-irradiated SiCOH, the diffused Cu is oxidized by the hydroxyl ions (OH{sup −}) generated from VUV irradiation and exists in the ionic state. The mechanisms for metal diffusion and ion injection in VUV irradiated low-k dielectrics are discussed.

  18. The Effect of Vacuum-Assisted Closure on the Bacterial Load and Type of Bacteria: A Systematic Review

    Science.gov (United States)

    Patmo, Aryan S.P.; Krijnen, Pieta; Tuinebreijer, Wim E.; Breederveld, Roelf S.

    2014-01-01

    Significance: A high bacterial load interferes with the healing process of a wound. Vacuum-assisted closure (VAC) is a wound healing therapy that utilizes a dressing system that continuously or intermittently applies a negative pressure to the wound surface. Recent Advances: VAC stimulates wound healing, but data on changes in the bacterial load and changes in the bacterial spectrum are scarce. Critical Issues: While VAC supposedly removes bacteria from the treated wounds and therefore reduces the risk of infection, this relationship has not yet been clinically proven. If VAC increases the bacterial load instead of decreasing it, then this may be a reason not to use VAC on certain types of wounds. Only seven small and heterogeneous studies reporting on the relationship between VAC usage and the bacterial load and type of bacteria in the treated wounds in clinical practice were found in the literature. Although there is some low quality evidence that VAC therapy does not change the bacterial load, no definite conclusions on changes in the bacterial load and type of bacteria during VAC can be drawn. Future Directions: Prospectively monitoring changes in the bacterial load and bacterial spectrum in patients that will receive VAC treatment on indication might be an effective way to find out whether it should indeed be used on specific wounds. PMID:24804158

  19. Residual effects of chromium gettering on the outgassing behavior of a stainless steel vacuum vessel

    International Nuclear Information System (INIS)

    Simpkins, J.E.; Blanchard, W.R.; Dylla, H.F.; LaMarche, P.H.

    1986-05-01

    Laboratory experiments that compared chromium and titanium gettering showed that with chromium, unlike titanium, there is no appreciable diffusion of hydrogen isotopes into the film. It was concluded from these experiments that chromium gettering on tokamaks is more desirable than titanium gettering, since chromium should provide higher hydrogen recycling, minimize tritium inventories, and avoid hydrogen embrittlement. Large-scale sublimation sources, consisting of hollow elongated chromium spheres with internal resistance heaters, were developed for use on tokamaks. These sources have been used to getter both the Impurity Study Experiment (ISX) and the Tokamak Fusion Test Reactor (TFTR). In both bases, significant effects on plasma performance were observed, including lower Z/sub eff/ and radiated power losses and an increase in the density limit. In TFTR these effects were observed for a period of weeks after a single chromium deposition. This paper reports the results of laboratory experiments made to examine the gettering characteristics of chromium films under conditions simulating those in TFTR

  20. Running vacuum cosmological models: linear scalar perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Perico, E.L.D. [Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, CEP 05508-090, São Paulo, SP (Brazil); Tamayo, D.A., E-mail: elduartep@usp.br, E-mail: tamayo@if.usp.br [Departamento de Astronomia, Universidade de São Paulo, Rua do Matão 1226, CEP 05508-900, São Paulo, SP (Brazil)

    2017-08-01

    In cosmology, phenomenologically motivated expressions for running vacuum are commonly parameterized as linear functions typically denoted by Λ( H {sup 2}) or Λ( R ). Such models assume an equation of state for the vacuum given by P-bar {sub Λ} = - ρ-bar {sub Λ}, relating its background pressure P-bar {sub Λ} with its mean energy density ρ-bar {sub Λ} ≡ Λ/8π G . This equation of state suggests that the vacuum dynamics is due to an interaction with the matter content of the universe. Most of the approaches studying the observational impact of these models only consider the interaction between the vacuum and the transient dominant matter component of the universe. We extend such models by assuming that the running vacuum is the sum of independent contributions, namely ρ-bar {sub Λ} = Σ {sub i} ρ-bar {sub Λ} {sub i} . Each Λ i vacuum component is associated and interacting with one of the i matter components in both the background and perturbation levels. We derive the evolution equations for the linear scalar vacuum and matter perturbations in those two scenarios, and identify the running vacuum imprints on the cosmic microwave background anisotropies as well as on the matter power spectrum. In the Λ( H {sup 2}) scenario the vacuum is coupled with every matter component, whereas the Λ( R ) description only leads to a coupling between vacuum and non-relativistic matter, producing different effects on the matter power spectrum.

  1. Fluctuation effects on average cross sections in compound, direct and doorway state resonance reactions

    International Nuclear Information System (INIS)

    Moldauer, P.A.

    1979-01-01

    The main features of the effects of S-matrix flucturations on average cross sections are reviewed with emphasis on recent developments on the enhancement of small cross sections and cross sections between directly coupled channels. Examples are given in which the effect can distort the shape of a doorway state resonance so as to reduce its observed width. 4 figures

  2. Effect of Islanding and Telecontrolled Switches on Distribution System Reliability Considering Load and Green-Energy Fluctuations

    Directory of Open Access Journals (Sweden)

    Stefania Conti

    2016-05-01

    Full Text Available To improve electrical distribution network reliability, some portions of the network could operate in autonomous mode, provided that the related technical issues are addressed. More specifically, when there is not a path from those portions to the primary substation due to a fault in the network, such portions could be disconnected from the main network and supplied by local generation only. Such a mode of operation is known as “intentional islanding” and its effectiveness, in terms of adequacy, depends on the ability of the local generation to meet the island’s load. In fact, the ratio between the available local generation and load demand can frequently change during islanding due to load variations and, especially, due to the strongly irregular behavior of the primary energy sources of renewable generators. This paper proposes an analytical formulation to assess local generation adequacy during intentional islanding, accounting for the aforementioned variations. More specifically, the fluctuations of load and green-energy generators during islanding are modeled by means of Markov chains, whose output quantities are encompassed in the proposed analytical formulation. Such a formulation is used by the analytical equations of load points’ outage rate and duration. The evaluation of the reliability indices accounts for a protection scheme based on an appropriate communication infrastructure. Therefore, a brief overview on the telecommunications technologies has been presented with reference to their suitability for the specific application. In particular, distribution network safety issues have been considered as the main concern. The results show that neglecting load and generation fluctuations leads to a strong overestimation of the ability of distributed generators to meet the island load. Through a case study it is observed that the error on the load point outage rate is greater than the one affecting the outage duration.

  3. Influence of Gap Distance on Vacuum Arc Characteristics of Cup Type AMF Electrode in Vacuum Interrupters

    International Nuclear Information System (INIS)

    Cheng Shaoyong; Xiu Shixin; Wang Jimei; Shen Zhengchao

    2006-01-01

    The greenhouse effect of SF 6 is a great concern today. The development of high voltage vacuum circuit breakers becomes more important. The vacuum circuit breaker has minimum pollution to the environment. The vacuum interrupter is the key part of a vacuum circuit breaker. The interrupting characteristics in vacuum and arc-controlling technique are the main problems to be solved for a longer gap distance in developing high voltage vacuum interrupters. To understand the vacuum arc characteristics and provide effective technique to control vacuum arc in a long gap distance, the arc mode transition of a cup-type axial magnetic field electrode is observed by a high-speed charge coupled device (CCD) video camera under different gap distances while the arc voltage and arc current are recorded. The controlling ability of the axial magnetic field on vacuum arc obviously decreases when the gap distance is longer than 40 mm. The noise components and mean value of the arc voltage significantly increase. The effective method for controlling the vacuum arc characteristics is provided by long gap distances based on the test results. The test results can be used as a reference to develop high voltage and large capacity vacuum interrupters

  4. Effect of vacuum arc cathode spot distribution on breaking capacity of the arc-extinguishing chamber

    Science.gov (United States)

    Ding, Can; Yuan, Zhao; He, Junjia

    2017-10-01

    A DC circuit breaker performs a key function in breaking an intermediate-frequency (IF) current since breaking a pure IF current is equivalent to breaking a very small DC with a reverse IF current. In this study, it is found that cathode spots show a ring-shaped distribution at 2000 Hz. An arc with an uneven distribution of cathode spots has been simulated. The simulation results show that the distribution of cathode spots significantly affect the microparameter distribution of arc plasma. The current distribution on the anode side differs from that on the cathode side under the total radial electric field. Specifically, the anode current distribution is both uneven and concentrated. The applied axial magnetic field, which cannot reduce the concentrated anode current distribution effectively, might increase the concentration of the anode current. Finally, the uneven distribution of cathode spots reduces the breaking capacity of the arc-extinguishing chamber.

  5. Quantum fluctuations from thermal fluctuations in Jacobson formalism

    Energy Technology Data Exchange (ETDEWEB)

    Faizal, Mir [University of British Columbia-Okanagan, Irving K. Barber School of Arts and Sciences, Kelowna, BC (Canada); University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada); Ashour, Amani; Alcheikh, Mohammad [Damascus University, Mathematics Department, Faculty of Science, Damascus (Syrian Arab Republic); Alasfar, Lina [Universite Clermont Auvergne, Laboratoire de Physique Corpusculaire de Clermont-Ferrand, Aubiere (France); Alsaleh, Salwa; Mahroussah, Ahmed [King Saud University, Department of Physics and Astronomy, Riyadh (Saudi Arabia)

    2017-09-15

    In the Jacobson formalism general relativity is obtained from thermodynamics. This is done by using the Bekenstein-Hawking entropy-area relation. However, as a black hole gets smaller, its temperature will increase. This will cause the thermal fluctuations to also increase, and these will in turn correct the Bekenstein-Hawking entropy-area relation. Furthermore, with the reduction in the size of the black hole, quantum effects will also start to dominate. Just as the general relativity can be obtained from thermodynamics in the Jacobson formalism, we propose that the quantum fluctuations to the geometry can be obtained from thermal fluctuations. (orig.)

  6. Rederivation of the alpha effect in terms of the magnetic fluctuation spectrum

    International Nuclear Information System (INIS)

    Keinigs, R.K.; Gerwin, R.A.

    1982-08-01

    We demonstrate that the alpha effect can be expressed in terms of the integrated current helicity spectrum of the turbulence. This is a much more convenient form than that obtained using a kinematic velocity field description

  7. Indian Vacuum Society: The Indian Vacuum Society

    Science.gov (United States)

    Saha, T. K.

    2008-03-01

    The Indian Vacuum Society (IVS) was established in 1970. It has over 800 members including many from Industry and R & D Institutions spread throughout India. The society has an active chapter at Kolkata. The society was formed with the main aim to promote, encourage and develop the growth of Vacuum Science, Techniques and Applications in India. In order to achieve this aim it has conducted a number of short term courses at graduate and technician levels on vacuum science and technology on topics ranging from low vacuum to ultrahigh vacuum So far it has conducted 39 such courses at different parts of the country and imparted training to more than 1200 persons in the field. Some of these courses were in-plant training courses conducted on the premises of the establishment and designed to take care of the special needs of the establishment. IVS also regularly conducts national and international seminars and symposia on vacuum science and technology with special emphasis on some theme related to applications of vacuum. A large number of delegates from all over India take part in the deliberations of such seminars and symposia and present their work. IVS also arranges technical visits to different industries and research institutes. The society also helped in the UNESCO sponsored post-graduate level courses in vacuum science, technology and applications conducted by Mumbai University. The society has also designed a certificate and diploma course for graduate level students studying vacuum science and technology and has submitted a syllabus to the academic council of the University of Mumbai for their approval, we hope that some colleges affiliated to the university will start this course from the coming academic year. IVS extended its support in standardizing many of the vacuum instruments and played a vital role in helping to set up a Regional Testing Centre along with BARC. As part of the development of vacuum education, the society arranges the participation of

  8. The effect of temperature on photosynthetic induction under fluctuating light in Chrysanthemum morifolium

    DEFF Research Database (Denmark)

    Öztürk, Isik; Ottosen, Carl-Otto; Ritz, Christian

    2013-01-01

    for photosynthetic induction. Gas exchange measurements were used to investigate the rate of induction and the opening of stomata. It was determined that induction equilibrium for C. morifolium at varying temperatures under dynamic light conditions was reached within 15 to 45 minutes except at saturating light...... intensity. For the same photon irradiance, the momentary state of induction equilibrated was higher approximately at 30° C and it decreased as temperature increased. The interaction effect of irradiance and temperature on induction equilibrium was not significant. The rate of photosynthetic induction...... and the time that it reached its 90% value (t90) was influenced by irradiance significantly. The light history of a leaf had a significant effect on t90, which indicated that an equilibrium state of induction will not always be reached within the same time. The effect of temperature on photosynthetic induction...

  9. Annealing effect of thermal spike in MgO thin film prepared by cathodic vacuum arc deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Daoyun, E-mail: zhudy@gdut.edu.cn [Experiment Teaching Department, Guangdong University of Technology, Guangzhou 510006 (China); State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Zhao, Shoubai [School of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510400 (China); Zheng, Changxi; Chen, Dihu [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); He, Zhenhui, E-mail: stshzh@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2013-12-16

    MgO films were prepared by using pulsed cathodic vacuum arc deposition technique. The substrate bias voltage was in the range of −150 to −750 V. Film structure was investigated by X-ray diffraction (XRD). The annealing effect of thermal spike produced by the impacting of energetic ions was analyzed. The calculated results showed that the lifetime of a thermal spike generated by an energetic ion with the energy of 150 eV was less than one picosecond and it was sufficient to allow Mg{sup 2+} or O{sup 2-} to move one bond length to satisfy the intrinsic stress relief in the affected volume. The MgO(200) lattice spacings of the films deposited at different bias voltages were all larger than the ideal value of 2.1056 Å. As the bias amplitude increased the lattice spacing decreased, which indicated that the compressive stress in the film was partially relieved with increasing impacting ion energy. The stress relief also could be reflected from the film orientation with bias voltage. The biaxial elastic modulus for MgO(100), MgO(110) and MgO(111) planes were calculated and they were M{sub (100)} = 199 GPa, M{sub (110)} = 335 GPa and M{sub (111)} = 340 GPa, respectively. The M values indicated that the preferred orientation will be MgO(200) due to the minimum energy configuration when the lattice strain was large. It was confirmed by the XRD results in our experiments. - Highlights: • MgO thin films with preferred orientation were obtained by CVAD technique. • Annealing effect of a thermal spike in MgO film was discussed. • Lattice spacing of MgO film decreased with the increase of bias voltage. • Film preferred orientation changed from (200) to (220) as the bias voltage increased.

  10. The Effect of Long Memory in Volatility on Stock Market Fluctuations

    DEFF Research Database (Denmark)

    Christensen, Bent Jesper; Nielsen, Morten Ørregaard

    2007-01-01

    on returns. Asset pricing theory imposes testable cross-equation restrictions on the system that are not rejected in our preferred specifications, which include a strong financial leverage effect. We show that the impact of volatility shocks on stock prices is small and short-lived, in spite of a positive...

  11. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure

    NARCIS (Netherlands)

    Mashad, El H.; Zeeman, G.; Loon, van W.K.P.; Bot, G.P.A.; Lettinga, G.

    2004-01-01

    The influence of temperature, 50 and 60 °C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature

  12. The Effect of Long Memory in Volatility on Stock Market Fluctuations

    DEFF Research Database (Denmark)

    Christensen, Bent Jesper; Nielsen, Morten Ørregaard

    on returns. Asset pricing theory imposes testable cross- equation restrictions on the system that are not rejected in our preferred specifications, which include a strong financial leverage effect. We show that the impact of volatility shocks on stock prices is small and short-lived, in spite of a positive...

  13. The Effect of Long Memory in Volatility on Stock Market Fluctuations

    DEFF Research Database (Denmark)

    Christensen, Bent Jesper; Nielsen, Morten Ørregaard

    on returns. Asset pricing theory imposes testable cross-equation restrictions on the system that are not rejected in our preferred specifications, which include a strong financial leverage effect. We show that the impact of volatility shocks on stock prices is small and short-lived, in spite of a positive...

  14. The effect of groundwater fluctuations on the velocity pattern of slow-moving landslides

    NARCIS (Netherlands)

    Van Asch, T.W.J.; Malet, J.P.; Bogaard, T.A.

    2009-01-01

    Slow-moving landslides show complex mechanical and fluid interactions. They show among others non linear intrinsic viscosity of the shear zone, undrained loading effects and the generation of excess pore water pressure. The parameterization of hydrological and geomechanical factors by field and

  15. Effect of static charge fluctuations on the conduction along the edge of two-dimensional topological insulator

    Science.gov (United States)

    Vayrynen, Jukka; Goldstein, Moshe; Glazman, Leonid

    2013-03-01

    Static charge disorder may create electron puddles in the bulk of a material which nominally is in the insulating state. A single puddle - quantum dot - coupled to the helical edge of a two-dimensional topological insulator enhances the electron backscattering within the edge. The backscattering rate increases with the electron dwelling time in the dot. While remaining inelastic, the backscattering off a dot may be far more effective than the proposed earlier inelastic processes involving a local scatterer with no internal structure. We find the temperature dependence of the dot-induced correction to the universal conductance of the edge. In addition to the single-dot effect, we calculate the classical temperature-independent conductance correction caused by a weakly conducting bulk. We use our theory to assess the effect of static charge fluctuations in a heterostructure on the edge electron transport in a two-dimensional topological insulator. The work at Yale University is supported by NSF DMR Grant No. 1206612 and the Simons Foundation.

  16. Deformation and concentration fluctuations under stretching in a polymer network with free chains. The ``butterfly`` effect; Fluctuations de deformation et de concentration sous etirement dans un reseau polymere contenant des chaines libres. L`effet ``papillon``

    Energy Technology Data Exchange (ETDEWEB)

    Ramzi, A

    1994-06-01

    Small Angle Neutron Scattering gives access to concentration fluctuations of mobile labeled polymer chains embedded in a polymer network. At rest they appear progressively larger than for random mixing, with increasing ratio. Under uniaxial stretching, they decrease towards ideal mixing along the direction perpendicular to stretching, and can grow strongly along the parallel one, including the zero scattering vector q limit. This gives rise to intensity contours with double-winged patterns, in the shape of the figure `8`, or of `butterfly`. Random crosslinking and end-linking of monodisperse chains have both been studied. The strength of the `butterfly` effect increases with the molecular weight of the free chains, the crosslinking ratio, the network heterogeneity, and the elongation ratio. Eventually, the signal collapses on an `asymptotic` function I(q), of increasing correlation length with the elongation ratio. Deformation appears heterogeneous, maximal for soft areas, where the mobile chains localize preferentially. This could be due to spontaneous fluctuations, or linked to frozen fluctuations of the crosslink density. However, disagreement with the corresponding theoretical expressions makes it necessary to account for the spatial correlations of crosslink density, and their progressive unscreening as displayed by the asymptotic behavior. Networks containing pending labeled chains and free labeled stars lead to more precise understanding of the diffusion of free species and the heterogeneity of the deformation. It seems that the latter occurs even without diffusion for heterogeneous enough networks. In extreme cases (of the crosslinking parameters), the spatial correlations display on apparent fractal behavior, of dimensions 2 to 2.5, which is discussed here in terms of random clusters. 200 refs., 95 figs., 21 tabs., 10 appends.

  17. Effective field theory of an anomalous Hall metal from interband quantum fluctuations

    Science.gov (United States)

    Chua, Victor; Assawasunthonnet, Wathid; Fradkin, Eduardo

    2017-07-01

    We construct an effective field theory, a two-dimensional two-component metallic system described by a model with two Fermi surfaces ("pockets"). This model describes a translationally invariant metallic system with two types of fermions, each with its own Fermi surface, with forward scattering interactions. This model, in addition to the O (2 ) rotational invariance, has a U (1 )×U (1 ) symmetry of separate charge conservation for each Fermi surface. For sufficiently attractive interactions in the d -wave (quadrupolar) channel, this model has an interesting phase diagram that includes a spontaneously generated anomalous Hall metal phase. We derive the Landau-Ginzburg effective action of quadrupolar order parameter fields which enjoys an O (2 )×U (1 ) global symmetry associated to spatial isotropy and the internal U (1 ) relative phase symmetries, respectively. We show that the order parameter theory is dynamically local with a dynamical scaling of z =2 and perform a one-loop renormalization group analysis of the Landau-Ginzburg theory. The electronic liquid crystal phases that result from spontaneous symmetry breaking are studied and we show the presence of Landau damped Nambu-Goldstone modes at low momenta that is a signature of non-Fermi-liquid behavior. Electromagnetic linear response is also analyzed in both the normal and symmetry broken phases from the point of view of the order parameter theory. The nature of the coupling of electromagnetism to the order parameter fields in the normal phase is non-minimal and decidedly contains a precursor to the anomalous Hall response in the form of a order-parameter-dependent Chern-Simons term in the effective action.

  18. The Effect of Long Memory in Volatility on Stock Market Fluctuations

    DEFF Research Database (Denmark)

    Christensen, Bent Jesper; Nielsen, Morten Ørregaard

    2007-01-01

    Recent empirical evidence demonstrates the presence of an important long memory component in realized asset return volatility. We specify and estimate multivariate models for the joint dynamics of stock returns and volatility that allow for long memory in volatility without imposing this property...... on returns. Asset pricing theory imposes testable cross-equation restrictions on the system that are not rejected in our preferred specifications, which include a strong financial leverage effect. We show that the impact of volatility shocks on stock prices is small and short-lived, in spite of a positive...

  19. Equilibrium charge fluctuations of a charge detector and its effect on a nearby quantum dot

    Science.gov (United States)

    Ruiz-Tijerina, David; Vernek, Edson; Ulloa, Sergio

    2014-03-01

    We study the Kondo state of a spin-1/2 quantum dot (QD), in close proximity to a quantum point contact (QPC) charge detector near the conductance regime of the 0.7 anomaly. The electrostatic coupling between the QD and QPC introduces a remote gate on the QD level, which varies with the QPC gate voltage. Furthermore, models for the 0.7 anomaly [Y. Meir et al., PRL 89,196802(2002)] suggest that the QPC lodges a Kondo-screened level with charge-correlated hybridization, which may be also affected by capacitive coupling to the QD, giving rise to a competition between the two Kondo ground states. We model the QD-QPC system as two capacitively-coupled Kondo impurities, and explore the zero-bias transport of both the QD and the QPC for different local gate voltages and coupling strengths, using the numerical renormalization group and variational methods. We find that the capacitive coupling produces a remote gating effect, non-monotonic in the gate voltages, which reduces the gate voltage window for Kondo screening in either impurity, and which can also drive a quantum phase transition out of the Kondo regime. Our study is carried out for intermediate coupling strengths, and as such is highly relevant to experiments; particularly, to recent studies of decoherence effects on QDs. Supported by MWN/CIAM and NSF PIRE.

  20. Effects of periods of nonuse and fluctuating ammonia concentration on biofilter performance.

    Science.gov (United States)

    Chen, Ying-Xu; Yin, Jun; Wang, Kai-Xiong; Fang, Shi

    2004-01-01

    A systematic study on the transient behavior of odor treatment using biofilters is described. The biofilters were exposed to variations in contaminant loading and periods of nonuse. Two bench-scale biofilters with different filter media were used. Mixtures of compost/perlite (5:1) and dry sludge/granular active carbon (5:1) were used as filter media. Ammonia (NH3), one of the main malodorous gases, was used as the target compound. The response of each biofilter to variations in contaminant mass loading, periodic nonuse, water content, and inlet concentration pulse was studied. The nonuse period comprised of two stages: the "idle phase" when no air was passing through the biofilters, and the "no-contaminant-loading phase" when only humidified air was passing through the biofilters. Concentration spike was applied to study the effects of shock loading on the biofilter performance. Biofilters responded effectively to NH3 concentration variations and shock loading by rapidly recovering to the original removal rates within 6-12h. The results indicated re-acclimation times ranged from several hours to longer than a day. Longer idle phase produced longer re-acclimation periods than periods of no contaminant loading. When the media was dried during the biofiltration process, elimination capacity dropped accordingly for both biofilters. After 24 h of drying, the biofilter experiment could be restarted and run for a few days for recovering.