WorldWideScience

Sample records for relaxation frequencies reported

  1. Grid Cell Relaxation Effects on the High Frequency Vibration Characteristics

    International Nuclear Information System (INIS)

    Ryu, Joo-Young; Eom, Kyong-Bo; Jeon, Sang-Youn; Kim, Jae-Ik

    2015-01-01

    The plate structure of the grid of fuel assembly is always exposed to serious vortex induced vibration. Also, High Frequency flow induced Vibration (HFV) is primarily generated by vortex-shedding effect. When it comes to grid design as a fuel assembly component, HFV should be considered in advance since it is one of the critical factors. Excessive HFV has a possibility of making degradation of the fuel reliability that is directly related to the fuel robustness and operating performance. KEPCO NF (KNF) has performed HFV tests with various grid designs. While studying the HFV characteristics through the HFV tests, it has been observed that HFV amplitudes show different levels according to grid cell relaxation. It means that the testing could give different interpretations due to the condition of grid cell. Since the amount of relaxation is different under operating conditions and environments in a reactor, test specimens should be modified as much as possible to the real state of the fuel. Therefore, in order to consider the grid cell relaxation effects on the HFV tests, it is important to use cell sized or non-cell sized grids. The main focus of this study is to find out how the HFV characteristics such as amplitude and frequency are affected by grid cell relaxation. Three cases of the grid cell sized specimen which is nickel alloy were prepared and tested. Through the comparison of the test results, it could be concluded that HFV amplitudes show decreasing trend according to the grid cell relaxation in the case of nickel alloy grid. It is also possible to expect the tendency of grid cell relaxation of a zirconium alloy grid based on test results

  2. Predicting the effect of relaxation during frequency-selective adiabatic pulses

    Science.gov (United States)

    Pfaff, Annalise R.; McKee, Cailyn E.; Woelk, Klaus

    2017-11-01

    Adiabatic half and full passages are invaluable for achieving uniform, B1-insensitive excitation or inversion of macroscopic magnetization across a well-defined range of NMR frequencies. To accomplish narrow frequency ranges with adiabatic pulses (computer-calculated data with experimental results demonstrates that, in non-viscous, small-molecule fluids, it is possible to model magnetization and relaxation by considering standard T1 and T2 relaxation in the traditional rotating frame. The proposed model is aimed at performance optimizations of applications in which these pulses are employed. It differs from previous reports which focused on short high-power adiabatic pulses and relaxation that is governed by dipole-dipole interactions, cross polarization, or chemical exchange.

  3. Effect of gold nano-particles on switch-on voltage and relaxation frequency of nematic liquid crystal cell

    Directory of Open Access Journals (Sweden)

    M. Inam

    2011-12-01

    Full Text Available We report the observation of large changes in the electro-optical properties of nematic liquid crystal (NLC due to inclusion of small concentration of 10 nm diameter gold nanoparticles (GNPs. It is observed that GNPs lower switch-on voltage and also lower the relaxation frequency with applied voltage (AC field to NLC cell. These studies of GNP doped NLC cell have been done using optical interferometry and capacity measurement by impedance analyzer. The change in threshold voltage and relaxation frequency by doping GNPs in NLC is explained theoretically.

  4. Viscoelastic characterization of compacted pharmaceutical excipient materials by analysis of frequency-dependent mechanical relaxation processes

    Science.gov (United States)

    Welch, K.; Mousavi, S.; Lundberg, B.; Strømme, M.

    2005-09-01

    A newly developed method for determining the frequency-dependent complex Young's modulus was employed to analyze the mechanical response of compacted microcrystalline cellulose, sorbitol, ethyl cellulose and starch for frequencies up to 20 kHz. A Debye-like relaxation was observed in all the studied pharmaceutical excipient materials and a comparison with corresponding dielectric spectroscopy data was made. The location in frequency of the relaxation peak was shown to correlate to the measured tensile strength of the tablets, and the relaxation was interpreted as the vibrational response of the interparticle hydrogen and van der Waals bindings in the tablets. Further, the measured relaxation strength, holding information about the energy loss involved in the relaxation processes, showed that the weakest material in terms of tensile strength, starch, is the material among the four tested ones that is able to absorb the most energy within its structure when exposed to external perturbations inducing vibrations in the studied frequency range. The results indicate that mechanical relaxation analysis performed over relatively broad frequency ranges should be useful for predicting material properties of importance for the functionality of a material in applications such as, e.g., drug delivery, drug storage and handling, and also for clarifying the origin of hitherto unexplained molecular processes.

  5. Relaxation of inservice test frequency requirement for Kori 1 ASME code pumps

    International Nuclear Information System (INIS)

    Sohn, Gap Heon; Choi, Hae Yoon; Min, Kyung Sung; Rim, Nam Jin

    1994-08-01

    The objective of this investigation is to evaluate the technical and regulational requirements to justify the relaxation of the test frequency of Kori 1 pumps through reviewing the related rules and codes and standards, technical specifications of Kori 1 and other similar plants, standard technical specifications, research results for tech. spec. improvements and site test records. It is concluded that the relaxation of test frequency to quarterly be justified based on the conformance with rules and codes and standard, quarterly test cases in similar plants and standard tech. spec., recommendations of research result and stable site test records. (Author) 16 refs., 26 figs., 13 tabs

  6. The use of erbium fiber laser relaxation frequency for sensing refractive index and solute concentration of aqueous solutions

    International Nuclear Information System (INIS)

    Arellano-Sotelo, H; Barmenkov, Yu O; Kir'yanov, A V

    2008-01-01

    We report a novel-principle fiber-laser intra-cavity sensor for measuring refractive index and solute concentration of aqueous solutions. The sensor operation is based on a variation of the laser oscillation relaxation frequency (the measured parameter), sensitive to the intra-cavity loss change. The sensor capacity is demonstrated on the example of measurements of sugar concentration in water. A modeling of the sensor operation is presented, allowing its performance optimization

  7. Simultaneously Suppressing Low-Frequency and Relaxation Oscillation Intensity Noise in a DBR Single-Frequency Phosphate Fiber Laser

    International Nuclear Information System (INIS)

    Xiao Yu; Li Can; Xu Shan-Hui; Feng Zhou-Ming; Yang Chang-Sheng; Zhao Qi-Lai; Yang Zhong-Min

    2015-01-01

    Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward transfer function, which relates the laser output intensity to the pump modulations, is measured and analyzed. A custom two-path feedback system operating at different frequency bands is designed to adjust the pump current directly. The relative intensity noise is decreased by 20 dB from 0.2 to 5kHz and over 10 dB from 5 to 10 kHz. The relaxation oscillation peak is suppressed by 22 dB. In addition, a long term (24 h) laser instability of less than 0.05% is achieved. (paper)

  8. On-chip measurement of the Brownian relaxation frequency of magnetic beads using magnetic tunneling junctions

    DEFF Research Database (Denmark)

    Donolato, M.; Sogne, E.; Dalslet, Bjarke Thomas

    2011-01-01

    We demonstrate the detection of the Brownian relaxation frequency of 250 nm diameter magnetic beads using a lab-on-chip platform based on current lines for exciting the beads with alternating magnetic fields and highly sensitive magnetic tunnel junction (MTJ) sensors with a superparamagnetic free...

  9. Frequency and Temperature Dependence of Anharmonic Phonon Relaxation Rate in Carbon Nanotubes

    International Nuclear Information System (INIS)

    Hepplestone, S P; Srivastava, G P

    2007-01-01

    The relaxation rate of phonon modes in the (10, 10) single wall carbon nanotube undergoing three-phonon interactions at various temperatures has been studied using both qualitative and quantitative approaches based upon Fermi's Golden Rule and a quasi-elastic continuum model for the anharmonic potential. For the quantitative calculations, dispersion relations for the phonon modes were obtained from analytic expressions developed by Zhang et al. The qualitative expressions were derived using simple linear phonon dispersions relations. We show that in the high temperature regime the relaxation rate varies linearly with temperature and with the square of the frequency. In the low temperature regime we show that the relaxation rate varies exponentially with the inverse of temperature. These results have some very interesting implifications for effects for mean free path and thermal conductivity calculations

  10. Connecting structural relaxation with the low frequency modes in a hard-sphere colloidal glass.

    Science.gov (United States)

    Ghosh, Antina; Chikkadi, Vijayakumar; Schall, Peter; Bonn, Daniel

    2011-10-28

    Structural relaxation in hard-sphere colloidal glasses has been studied using confocal microscopy. The motion of individual particles is followed over long time scales to detect the rearranging regions in the system. We have used normal mode analysis to understand the origin of the rearranging regions. The low-frequency modes, obtained over short time scales, show strong spatial correlation with the rearrangements that happen on long time scales.

  11. Investigation of dielectric relaxation in systems with hierarchical organization: From time to frequency domain and back again

    Energy Technology Data Exchange (ETDEWEB)

    Yokoi, Koki [Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI (United States); Raicu, Valerică, E-mail: vraicu@uwm.edu [Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI (United States); Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI (United States)

    2017-06-28

    Relaxation in fractal structures was investigated theoretically starting from a simple model of a Cantorian tree and kinetic equations linking the change in the number of particles (e.g., electrical charges) populating each branch of the tree and their transfer to other branches or to the ground state. We numerically solved the system of differential equations obtained and determined the so-called cumulative distribution function of particles, which, in dielectric or mechanical relaxation parlance, is the same as the relaxation function of the system. As a physical application, we studied the relationship between the dielectric relaxation in time-domain and the dielectric dispersion in the frequency-domain. Upon choosing appropriate rate constants, our model described accurately well-known non-exponential and non-Debye time- and frequency-domain functions, such as stretched exponentials, Havrilliak–Negami, and frequency power law. Our approach opens the door to applying kinetic models to describe a wide array of relaxation processes, which traditionally have posed great challenges to theoretical modeling based on first principles. - Highlights: • Relaxation was investigated for a system of particles flowing through a Cantorian tree. • A set of kinetic equations was formulated and used to compute the relaxation function of the system. • The dispersion function of the system was computed from the relaxation function. • An analytical method was used to recover the original relaxation function from the dispersion function. • This formalism was used to study dielectric relaxation and dispersion in fractal structures.

  12. Time-domain simulation of constitutive relations for nonlinear acoustics including relaxation for frequency power law attenuation media modeling

    Science.gov (United States)

    Jiménez, Noé; Camarena, Francisco; Redondo, Javier; Sánchez-Morcillo, Víctor; Konofagou, Elisa E.

    2015-10-01

    We report a numerical method for solving the constitutive relations of nonlinear acoustics, where multiple relaxation processes are included in a generalized formulation that allows the time-domain numerical solution by an explicit finite differences scheme. Thus, the proposed physical model overcomes the limitations of the one-way Khokhlov-Zabolotskaya-Kuznetsov (KZK) type models and, due to the Lagrangian density is implicitly included in the calculation, the proposed method also overcomes the limitations of Westervelt equation in complex configurations for medical ultrasound. In order to model frequency power law attenuation and dispersion, such as observed in biological media, the relaxation parameters are fitted to both exact frequency power law attenuation/dispersion media and also empirically measured attenuation of a variety of tissues that does not fit an exact power law. Finally, a computational technique based on artificial relaxation is included to correct the non-negligible numerical dispersion of the finite difference scheme, and, on the other hand, improve stability trough artificial attenuation when shock waves are present. This technique avoids the use of high-order finite-differences schemes leading to fast calculations. The present algorithm is especially suited for practical configuration where spatial discontinuities are present in the domain (e.g. axisymmetric domains or zero normal velocity boundary conditions in general). The accuracy of the method is discussed by comparing the proposed simulation solutions to one dimensional analytical and k-space numerical solutions.

  13. Escape time, relaxation, and sticky states of a softened Henon-Heiles model: Low-frequency vibrational mode effects and glass relaxation

    Science.gov (United States)

    Toledo-Marín, J. Quetzalcóatl; Naumis, Gerardo G.

    2018-04-01

    Here we study the relaxation of a chain consisting of three masses joined by nonlinear springs and periodic conditions when the stiffness is weakened. This system, when expressed in their normal coordinates, yields a softened Henon-Heiles system. By reducing the stiffness of one low-frequency vibrational mode, a faster relaxation is enabled. This is due to a reduction of the energy barrier heights along the softened normal mode as well as for a widening of the opening channels of the energy landscape in configurational space. The relaxation is for the most part exponential, and can be explained by a simple flux equation. Yet, for some initial conditions the relaxation follows as a power law, and in many cases there is a regime change from exponential to power-law decay. We pinpoint the initial conditions for the power-law decay, finding two regions of sticky states. For such states, quasiperiodic orbits are found since almost for all components of the initial momentum orientation, the system is trapped inside two pockets of configurational space. The softened Henon-Heiles model presented here is intended as the simplest model in order to understand the interplay of rigidity, nonlinear interactions and relaxation for nonequilibrium systems such as glass-forming melts or soft matter. Our softened system can be applied to model β relaxation in glasses and suggest that local reorientational jumps can have an exponential and a nonexponential contribution for relaxation, the latter due to asymmetric molecules sticking in cages for certain orientations.

  14. A Comparison of Paraprofessionally Trained and Self-Instructed Relaxation Training for the Reduction in Frequency of Tension Headaches.

    Science.gov (United States)

    Hartman, Bruce W.; Utz, Patrick W.

    Previous research has demonstrated the effectiveness of using paraprofessional trainers in teaching students with tension headaches to relax, thus reducing the frequency of their headaches. A technique for automated self-instructed relaxation training was compared to a paraprofessionally trained group and a no-treatment control group over a 3-week…

  15. Low-frequency spatial wave manipulation via phononic crystals with relaxed cell symmetry

    International Nuclear Information System (INIS)

    Celli, Paolo; Gonella, Stefano

    2014-01-01

    Phononic crystals enjoy unique wave manipulation capabilities enabled by their periodic topologies. On one hand, they feature frequency-dependent directivity, which allows directional propagation of selected modes even at low frequencies. However, the stellar nature of the propagation patterns and the inability to induce single-beam focusing represent significant limitations of this functionality. On the other hand, one can realize waveguides by defecting the periodic structure of a crystal operating in bandgap mode along some desired path. Waveguides of this type are only activated in the relatively high and narrow frequency bands corresponding to total bandgaps, which limits their potential technological applications. In this work, we introduce a class of phononic crystals with relaxed cell symmetry and we exploit symmetry relaxation of a population of auxiliary microstructural elements to achieve spatial manipulation of elastic waves at very low frequencies, in the range of existence of the acoustic modes. By this approach, we achieve focusing without modifying the default static properties of the medium and by invoking mechanisms that are well suited to envision adaptive configurations for semi-active wave control

  16. Electron Tunneling in Lithium Ammonia Solutions Probed by Frequency-Dependent Electron-Spin Relaxation Studies

    Science.gov (United States)

    Maeda, Kiminori; Lodge, Matthew T.J.; Harmer, Jeffrey; Freed, Jack H.; Edwards, Peter P.

    2012-01-01

    Electron transfer or quantum tunneling dynamics for excess or solvated electrons in dilute lithium-ammonia solutions have been studied by pulse electron paramagnetic resonance (EPR) spectroscopy at both X- (9.7 GHz) and W-band (94 GHz) frequencies. The electron spin-lattice (T1) and spin-spin (T2) relaxation data indicate an extremely fast transfer or quantum tunneling rate of the solvated electron in these solutions which serves to modulate the hyperfine (Fermi-contact) interaction with nitrogen nuclei in the solvation shells of ammonia molecules surrounding the localized, solvated electron. The donor and acceptor states of the solvated electron in these solutions are the initial and final electron solvation sites found before, and after, the transfer or tunneling process. To interpret and model our electron spin relaxation data from the two observation EPR frequencies requires a consideration of a multi-exponential correlation function. The electron transfer or tunneling process that we monitor through the correlation time of the nitrogen Fermi-contact interaction has a time scale of (1–10)×10−12 s over a temperature range 230–290K in our most dilute solution of lithium in ammonia. Two types of electron-solvent interaction mechanisms are proposed to account for our experimental findings. The dominant electron spin relaxation mechanism results from an electron tunneling process characterized by a variable donor-acceptor distance or range (consistent with such a rapidly fluctuating liquid structure) in which the solvent shell that ultimately accepts the transferring electron is formed from random, thermal fluctuations of the liquid structure in, and around, a natural hole or Bjerrum-like defect vacancy in the liquid. Following transfer and capture of the tunneling electron, further solvent-cage relaxation with a timescale of ca. 10−13 s results in a minor contribution to the electron spin relaxation times. This investigation illustrates the great potential

  17. Electron tunneling in lithium-ammonia solutions probed by frequency-dependent electron spin relaxation studies.

    Science.gov (United States)

    Maeda, Kiminori; Lodge, Matthew T J; Harmer, Jeffrey; Freed, Jack H; Edwards, Peter P

    2012-06-06

    Electron transfer or quantum tunneling dynamics for excess or solvated electrons in dilute lithium-ammonia solutions have been studied by pulse electron paramagnetic resonance (EPR) spectroscopy at both X- (9.7 GHz) and W-band (94 GHz) frequencies. The electron spin-lattice (T(1)) and spin-spin (T(2)) relaxation data indicate an extremely fast transfer or quantum tunneling rate of the solvated electron in these solutions which serves to modulate the hyperfine (Fermi-contact) interaction with nitrogen nuclei in the solvation shells of ammonia molecules surrounding the localized, solvated electron. The donor and acceptor states of the solvated electron in these solutions are the initial and final electron solvation sites found before, and after, the transfer or tunneling process. To interpret and model our electron spin relaxation data from the two observation EPR frequencies requires a consideration of a multiexponential correlation function. The electron transfer or tunneling process that we monitor through the correlation time of the nitrogen Fermi-contact interaction has a time scale of (1-10) × 10(-12) s over a temperature range 230-290 K in our most dilute solution of lithium in ammonia. Two types of electron-solvent interaction mechanisms are proposed to account for our experimental findings. The dominant electron spin relaxation mechanism results from an electron tunneling process characterized by a variable donor-acceptor distance or range (consistent with such a rapidly fluctuating liquid structure) in which the solvent shell that ultimately accepts the transferring electron is formed from random, thermal fluctuations of the liquid structure in, and around, a natural hole or Bjerrum-like defect vacancy in the liquid. Following transfer and capture of the tunneling electron, further solvent-cage relaxation with a time scale of ∼10(-13) s results in a minor contribution to the electron spin relaxation times. This investigation illustrates the great

  18. Relaxation oscillations induced by amplitude-dependent frequency in dissipative trapped electron mode turbulence

    International Nuclear Information System (INIS)

    Terry, P.W.; Ware, A.S.; Newman, D.E.

    1994-01-01

    A nonlinear frequency shift in dissipative trapped electron mode turbulence is shown to give rise to a relaxation oscillation in the saturated power density spectrum. A simple non-Markovian closure for the coupled evolution of ion momentum and electron density response is developed to describe the oscillations. From solutions of a nonlinear oscillator model based on the closure, it is found that the oscillation is driven by the growth rate, as modified by the amplitude-dependent frequency shift, with inertia provided by the memory of the growth rate of prior amplitudes. This memory arises from time-history integrals common to statistical closures. The memory associated with a finite time of energy transfer between coupled spectrum components does not sustain the oscillation in the simple model. Solutions of the model agree qualitatively with the time-dependent numerical solutions of the original dissipative trapped electron model, yielding oscillations with the proper phase relationship between the fluctuation energy and the frequency shift, the proper evolution of the wave number spectrum shape and particle flux, and a realistic period

  19. The frequency-domain relaxation response of gallium doped Cd{sub 1-x}Mn{sub x}Te

    Energy Technology Data Exchange (ETDEWEB)

    Trzmiel, Justyna; Weron, Karina [Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Jurlewicz, Agnieszka [Hugo Steinhaus Center, Institute of Mathematics and Computer Science, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

    2010-03-10

    In this paper the complex dielectric permittivity of gallium doped Cd{sub 0.99}Mn{sub 0.01}Te mixed crystals is studied at different temperatures. We observe a two-power-law relaxation pattern with m and n, the low- and high-frequency power-law exponents respectively, satisfying the relation m < 1 - n. To interpret the empirical result we propose a correlated-cluster relaxation mechanism. This approach allows us to find origins of both power-law exponents, m and n.

  20. The time-dependence of exchange-induced relaxation during modulated radio frequency pulses.

    Science.gov (United States)

    Sorce, Dennis J; Michaeli, Shalom; Garwood, Michael

    2006-03-01

    The problem of the relaxation of identical spins 1/2 induced by chemical exchange between spins with different chemical shifts in the presence of time-dependent RF irradiation (in the first rotating frame) is considered for the fast exchange regime. The solution for the time evolution under the chemical exchange Hamiltonian in the tilted doubly rotating frame (TDRF) is presented. Detailed derivation is specified to the case of a two-site chemical exchange system with complete randomization between jumps of the exchanging spins. The derived theory can be applied to describe the modulation of the chemical exchange relaxation rate constants when using a train of adiabatic pulses, such as the hyperbolic secant pulse. Theory presented is valid for quantification of the exchange-induced time-dependent rotating frame longitudinal T1rho,ex and transverse T2rho,ex relaxations in the fast chemical exchange regime.

  1. Connecting structural relaxation with the low frequency modes in a hard-sphere colloidal glass

    NARCIS (Netherlands)

    Ghosh, A.; Chikkadi, V.; Schall, P.; Bonn, D.

    2011-01-01

    Structural relaxation in hard-sphere colloidal glasses has been studied using confocal microscopy. The motion of individual particles is followed over long time scales to detect the rearranging regions in the system. We have used normal mode analysis to understand the origin of the rearranging

  2. MDS 3.0 Frequency Report

    Data.gov (United States)

    U.S. Department of Health & Human Services — The MDS 3.0 Frequency Report summarizes information for active residents currently in nursing homes. The source of these counts is the residents MDS assessment...

  3. Nonlinear generation of non-acoustic modes by low-frequency sound in a vibrationally relaxing gas

    International Nuclear Information System (INIS)

    Perelomova, A.

    2010-01-01

    Two dynamic equations referring to a weakly nonlinear and weakly dispersive flow of a gas in which molecular vibrational relaxation takes place, are derived. The first one governs an excess temperature associated with the thermal mode, and the second one describes variations in vibrational energy. Both quantities refer to non-wave types of gas motion. These variations are caused by the nonlinear transfer of acoustic energy into thermal mode and internal vibrational degrees of freedom of a relaxing gas. The final dynamic equations are instantaneous; they include a quadratic nonlinear acoustic source, reflecting the nonlinear character of interaction of low-frequency acoustic and non-acoustic motions of the fluid. All types of sound, periodic or aperiodic, may serve as an acoustic source of both phenomena. The low-frequency sound is considered in this study. Some conclusions about temporal behavior of non-acoustic modes caused by periodic and aperiodic sound are made. Under certain conditions, acoustic cooling takes place instead of heating. (author)

  4. Relaxation dynamics of the conductive processes for PbNb2O6 ferroelectric ceramics in the frequency and time domain

    International Nuclear Information System (INIS)

    Gonzalez, R L; Leyet, Y; Guerrero, F; Guerra, J de Los S; Venet, M; Eiras, J A

    2007-01-01

    The relaxation dynamics of the conductive process present in PbNb 2 O 6 piezoelectric ceramics was investigated. A relaxation function in the time domain, Φ(t), was found from the frequency dependence of the dielectric modulus (imaginary component, M'') by using a relaxation function in the frequency domain, F*(ω). The best relaxation function, F*(ω), was found to be a Cole-Cole distribution function, in which relaxation characteristic parameters, such as α and τ CC , are involved. On the other hand, the relaxation function, Φ(t), obtained by the time domain method, was found to be a Kohlrausch-Williams-Watts (KWW) function type. The thermal evolution of the characteristics parameters of the KWW function (β and τ*) was analysed. The values of the activation energy (E a ), obtained in the whole investigated temperature interval, suggest the existence of a relaxation mechanism (a conductive process), which may be interpreted by an ion hopping between neighbouring sites within the crystalline lattice. The results are corroborated with the formalism of the AC conductivity

  5. Low frequency ac conduction and dielectric relaxation in poly(N ...

    Indian Academy of Sciences (India)

    The ac conductivity and dielectric constant of poly(N-methyl pyrrole) thin films have been investigated in the temperature range 77–350 K and in the frequency range 102–106 Hz. The well defined loss peaks have been observed in the temperature region where measured ac conductivity approaches dc conductivity.

  6. Low frequency ac conduction and dielectric relaxation in poly(N ...

    Indian Academy of Sciences (India)

    Unknown

    polymer chain in the form of bands analogous to that of a semiconductor and the ... these materials a model has been proposed which suggests the application of two .... values is almost equal to dc conductivity value while in high frequency ...

  7. Enhanced magnetic domain relaxation frequency and low power losses in Zn{sup 2+} substituted manganese ferrites potential for high frequency applications

    Energy Technology Data Exchange (ETDEWEB)

    Praveena, K., E-mail: praveenaou@gmail.com [Department of Physics, National Taiwan Normal University, Taipei, 11677, Taiwan (China); Chen, Hsiao-Wen [Department of Physics, National Taiwan Normal University, Taipei, 11677, Taiwan (China); Liu, Hsiang-Lin, E-mail: hliu@ntnu.edu.tw [Department of Physics, National Taiwan Normal University, Taipei, 11677, Taiwan (China); Sadhana, K., E-mail: sadhana@osmania.ac.in [Department of Physics, Osmania University, Saifabad, Hyderabad, 500004 (India); Murthy, S.R. [Department of Physics, Osmania University, Hyderabad, 500007 (India)

    2016-12-15

    Nowadays electronic industries prerequisites magnetic materials, i.e., iron rich materials and their magnetic alloys. However, with the advent of high frequency applications, the standard techniques of reducing eddy current losses, using iron cores, were no longer efficient or cost effective. Current market trends of the switched mode power supplies industries required even low energy losses in power conversion with maintenance of adequate initial permeability. From the above point of view, in the present study we aimed at the production of Manganese–Zinc ferrites prepared via solution combustion method using mixture of fuels and achieved low loss, high saturation magnetization, high permeability, and high magnetic domain relaxation frequency. The as-synthesized Zn{sup 2+} substituted MnFe{sub 2}O{sub 4} were characterized by X-ray diffractometer (XRD) and transmission electron microscopy (TEM). The fractions of Mn{sup 2+}, Zn{sup 2+} and Fe{sup 2+} cations occupying tetrahedral sites along with Fe occupying octahedral sites within the unit cell of all ferrite samples were estimated by Raman scattering spectroscopy. The magnetic domain relaxation was investigated by inductance spectroscopy (IS) and the observed magnetic domain relaxation frequency (f{sub r}) was increased with the increase in grain size. The real and imaginary part of permeability (μ′ and μ″) increased with frequency and showed a maximum above 100 MHz. This can be explained on the basis of spin rotation and domain wall motion. The saturation magnetization (M{sub s}), remnant magnetization (M{sub r}) and magneton number (µ{sub B}) decreased gradually with increasing Zn{sup 2+} concentration. The decrease in the saturation magnetization was discussed with Yafet–Kittel (Y–K) model. The Zn{sup 2+} concentration increases the relative number of ferric ions on the A sites, reduces the A–B interactions. The frequency dependent total power losses decreased as the zinc concentration increased

  8. [Effects of Monochord Music on Heart Rate Variability and Self-Reports of Relaxation in Healthy Adults].

    Science.gov (United States)

    Gäbel, Christine; Garrido, Natalia; Koenig, Julian; Hillecke, Thomas Karl; Warth, Marco

    Music-based interventions are considered an effective and low-cost treatment option for stress-related symptoms. The present study aimed to examine the trajectories of the psychophysiological response in apparently healthy participants during a music-based relaxation intervention compared to a verbal relaxation exercise. 70 participants were assigned to either receptive live music (experimental group) or a prerecorded verbal relaxation exercise (control group). Self-ratings of relaxation were assessed before and after each intervention on visual analogue scales and the Relaxation Inventory (RI). The heart rate variability (HRV) was continuously recorded throughout the sessions. Statistical analysis focused on HRV parameters indicative of parasympathetic cardiovascular outflow. We found significant quadratic main effects for time on the mean R-R interval (heart rate), the high-frequency power of HRV (indicative of parasympathetic activity), and the self-ratings of relaxation in both groups. A significant group × time interaction was observed for the cognitive tension subscale of the RI. Participants in both groups showed psychophysiological changes indicative of greater relaxation over the course of the interventions. However, differences between groups were only marginal. Music might be effective in relieving stress and promoting relaxation by altering the autonomic nervous system function. Future studies need to explore the long-term outcomes of such interventions. © 2017 S. Karger GmbH, Freiburg.

  9. Optimal duration of ultra low frequency-transcutaneous electrical nerve stimulation (ULF-TENS) therapy for muscular relaxation in neuromuscular occlusion: A preliminary clinical study.

    Science.gov (United States)

    Esclassan, Rémi; Rumerio, Anaïs; Monsarrat, Paul; Combadazou, Jean Claude; Champion, Jean; Destruhaut, Florent; Ghrenassia, Christophe

    2017-05-01

    The primary aim of this work was to determine the duration of ultra-low-frequency transcutaneous electrical nerve stimulation (ULF-TENS) application necessary to achieve sufficient relaxation of the masticatory muscles. A secondary aim was to analyze the influence of stimulation on muscle relaxation in pathological subjects and determine whether ULF-TENS has a noteworthy impact on muscle relaxation. Sixteen adult subjects with temporomandibular disorders (TMD) and muscle pain and a group of four control subjects were included in this study. ULF-TENS was applied, and muscular activities of the masseter, temporal, and sternocleidomastoid muscles (SCM) were recorded for 60 min. Significant relaxation was achieved in the TMD group from 20, 40, and 60 min for the temporal, masseter, and SCM muscles (p TENS application would last 40 min to obtain sufficient muscle relaxation both in patients with masticatory system disorders and healthy subjects, a time constraint that is consistent with everyday clinical practice.

  10. Voltage, Temperature, Frequency Margin Test Report

    DEFF Research Database (Denmark)

    Denver, Troelz

    1999-01-01

    The purpose of the tests is to establish the camera functionality when it is exposed to an extreme environment for prolonged periods, thus simulating the end of life performance. This environment covers temperature, input clock frequency and supply voltage variation......The purpose of the tests is to establish the camera functionality when it is exposed to an extreme environment for prolonged periods, thus simulating the end of life performance. This environment covers temperature, input clock frequency and supply voltage variation...

  11. Phase synchronization in a two-mode solid state laser: Periodic modulations with the second relaxation oscillation frequency of the laser output

    International Nuclear Information System (INIS)

    Hsu, Tzu-Fang; Jao, Kuan-Hsuan; Hung, Yao-Chen

    2014-01-01

    Phase synchronization (PS) in a periodically pump-modulated two-mode solid state laser is investigated. Although PS in the laser system has been demonstrated in response to a periodic modulation with the main relaxation oscillation (RO) frequency of the free-running laser, little is known about the case of modulation with minor RO frequencies. In this Letter, the empirical mode decomposition (EMD) method is utilized to decompose the laser time series into a set of orthogonal modes and to examine the intrinsic PS near the frequency of the second RO. The degree of PS is quantified by means of a histogram of phase differences and the analysis of Shannon entropy. - Highlights: • We study the intrinsic phase synchronization in a periodically pump-modulated two-mode solid state laser. • The empirical mode decomposition method is utilized to define the intrinsic phase synchronization. • The degree of phase synchronization is quantified by a proposed synchronization coefficient

  12. Low frequency dielectric relaxation processes and ionic conductivity of montmorillonite clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone−ethylene glycol blends

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available The dielectric dispersion behaviour of montmorillonite (MMT clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone-ethylene glycol (PVP-EG blends were investigated over the frequency range 20 Hz to 1 MHz at 30°C. The 0, 1, 2, 3, 5 and 10 wt% MMT clay concentration of the weight of total solute (MMT+PVP were prepared in PVP-EG blends using EG as solvent. The complex relative dielectric function, alternating current (ac electrical conductivity, electric modulus and impedance spectra of these materials show the relaxation processes corresponding to the micro-Brownian motion of PVP chain, ion conduction and electrode polarization phenomena. The real part of ac conductivity spectra of these materials obeys Jonscher power law σ′(ω =σdc + Aωn in upper frequency end of the measurement, whereas dispersion in lower frequency end confirms the presence of electrode polarization effect. It was observed that the increase of clay concentration in the PVP-EG blends significantly increases the ac conductivity values, and simultaneously reduces the ionic conductivity relaxation time and electric double layer relaxation time, which suggests that PVP segmental dynamics and ionic motion are strongly coupled. The intercalation of EG structures in clay galleries and exfoliation of clay sheets by adsorption of PVP-EG structures on clay surfaces are discussed by considering the hydrogen bonding interactions between the hydroxyl group (–OH of EG molecules, carbonyl group (C=O of PVP monomer units, and the hydroxylated aluminate surfaces of the MMT clay particles. Results suggest that the colloidal suspension of MMT clay nano particles in the PVP-EG blends provide a convenient way to obtain an electrolyte solution with tailored electrical conduction properties.

  13. Electronic relaxation processes in polyatomic molecules. Progress report, October 1, 1975--September 30, 1976

    International Nuclear Information System (INIS)

    Lim, E.C.

    1976-09-01

    Excitation energy dependence of radiationless decay rate under collision-free conditions was utilized as a probe of intramolecular vibrational relaxation in tetracene and pentacene. The results give evidence of vibrational relaxation which competes with electronic relaxation. The substitution dependence of T 1 (nπ*) → S 0 radiationless transition in monocyclic diazines and the temperature dependence of S 1 non-radiative decay rate in alcoholic solutions of polycyclic monoazines indicate that the vibronic interaction between the lowest energy nπ* and ππ* states leads to a rapid radiationless deactivation of the lower of the two electronic states. Finally, a photon-counting spectrofluorometer of very high sensitivity was constructed, and it was used to record T 2 → T 1 fluorescence in bromoanthracenes and S 2 → S 1 fluorescence in azulene. These spectra represent the first bona-fide, or the most convincing, observation of fluorescence between excited electronic states

  14. Multidimensional Test Assembly Based on Lagrangian Relaxation Techniques. Research Report 98-08.

    Science.gov (United States)

    Veldkamp, Bernard P.

    In this paper, a mathematical programming approach is presented for the assembly of ability tests measuring multiple traits. The values of the variance functions of the estimators of the traits are minimized, while test specifications are met. The approach is based on Lagrangian relaxation techniques and provides good results for the two…

  15. Passivation of boron in silicon by hydrogen and muonium: calculation of electric field gradients, quadrupole resonance frequencies and cross relaxation functions

    International Nuclear Information System (INIS)

    Maric, Dj.M.; Meier, P.F.; Vogel, S.; Davis, E.A.

    1991-01-01

    The possibility of studying impurity passivation complexes in semiconductors by quadrupole resonance spectroscopy is examined. The problem is illustrated for the case of boron in silicon passivated with hydrogen or, equivalently, with muonium, since the radioactive light isotope in principle offers a greater sensitivity for detection of the spectra. Ab initio calculations on suitable cluster models of the passivation complexes provide estimates of the electric field gradients at the quadrupolar nuclei, and thereby predictions of the quadrupole resonance frequencies. Detection via cross-relaxation techniques is proposed, notably muon level crossing resonance (μLCR), and illustrated by calculation of the time dependence of the muon polarization function. Possible reasons for the absence of quadrupolar resonances in μLCR spectra recorded in exploratory experiments are discussed; these include the existence of a local tunnelling mode for the lighter isotope. (author)

  16. Structural relaxation dynamics and annealing effects of sodium silicate glass.

    Science.gov (United States)

    Naji, Mohamed; Piazza, Francesco; Guimbretière, Guillaume; Canizarès, Aurélien; Vaills, Yann

    2013-05-09

    Here we report high-precision measurements of structural relaxation dynamics in the glass transition range at the intermediate and short length scale for a strong sodium silicate glass during long annealing times. We evidence for the first time the heterogeneous dynamics at the intermediate range order by probing the acoustic longitudinal frequency in the GHz region by Brillouin light scattering spectroscopy. Or, from in-situ Raman measurements, we show that relaxation is indeed homogeneous at the interatomic length scale. Our results show that the dynamics at the intermediate range order contains two distinct relaxation time scales, a fast and a slow component, differing by about a 10-fold factor below Tg and approaching to one another past the glass transition. The slow relaxation time agrees with the shear relaxation time, proving that Si-O bond breaking constitutes the primary control of structural relaxation at the intermediate range order.

  17. Capturing molecular multimode relaxation processes in excitable gases based on decomposition of acoustic relaxation spectra

    Science.gov (United States)

    Zhu, Ming; Liu, Tingting; Wang, Shu; Zhang, Kesheng

    2017-08-01

    Existing two-frequency reconstructive methods can only capture primary (single) molecular relaxation processes in excitable gases. In this paper, we present a reconstructive method based on the novel decomposition of frequency-dependent acoustic relaxation spectra to capture the entire molecular multimode relaxation process. This decomposition of acoustic relaxation spectra is developed from the frequency-dependent effective specific heat, indicating that a multi-relaxation process is the sum of the interior single-relaxation processes. Based on this decomposition, we can reconstruct the entire multi-relaxation process by capturing the relaxation times and relaxation strengths of N interior single-relaxation processes, using the measurements of acoustic absorption and sound speed at 2N frequencies. Experimental data for the gas mixtures CO2-N2 and CO2-O2 validate our decomposition and reconstruction approach.

  18. Forest cover, socioeconomics, and reported flood frequency in developing countries

    Science.gov (United States)

    Ferreira, Susana; Ghimire, Ramesh

    2012-08-01

    In this paper, we analyze the determinants of the number of large floods reported since 1990. Using the same sample of countries as Bradshaw et al. (2007), and, like them, omitting socioeconomic characteristics from the analysis, we found that a reduction in natural forest cover is associated with an increase in the reported count of large floods. This result does not hold in any of three new analyses we perform. First, we expand the sample to include all the developing countries and all countries for which data were available but were omitted in their study. Second, and more importantly, since forest management is just one possible channel through which humans can influence reported flood frequency, we account for other important human-flood interactions. People are typically responsible for deforestation, but they are also responsible for other land use changes (e.g., urbanization), for floodplain and flood emergency management, and for reporting the floods. Thus, in our analysis we account for population, urban population growth, income, and corruption. Third, we exploit the panel nature of the data to control for unobserved country and time heterogeneity. We conclude that not only is the link between forest cover and reported flood frequency at the country level not robust, it also seems to be driven by sample selection and omitted variable bias. The human impact on the reported frequency of large floods at the country level is not through deforestation.

  19. Stepped frequency imaging for flaw monitoring: Final report

    International Nuclear Information System (INIS)

    Hildebrand, B.P.

    1988-09-01

    This report summarizes the results of research into the usefulness of stepped frequency imaging (SFI) to nuclear power plant inspection. SFI is a method for producing ultrasonic holographic images without the need to sweep a two-dimensional aperture with the transducer. Instead, the transducer may be translated along a line. At each position of the transducer the frequency is stepped over a finite preselected bandwidth. The frequency stepped data is then processed to synthesize the second dimension. In this way it is possible to generate images in regions that are relatively inaccessible to two-dimensional scanners. This report reviews the theory and experimental work verifying the technique, and then explores its possible applications in the nuclear power industry. It also outlines how this new capability can be incorporated into the SDL-1000 Imaging System previously developed for EPRI. The report concludes with five suggestions for uses for the SFI method. These are: monitoring suspect or repaired regions of feedwater nozzles; monitoring pipe cracks repaired by weld overlay; monitoring crack depth during test block production; imaging flaws where access is difficult; and imaging flaws through cladding without distortion

  20. Ingestion of a carbonated beverage decreases lower esophageal sphincter pressure and increases frequency of transient lower esophageal sphincter relaxation in normal subjects.

    Science.gov (United States)

    Shukla, Akash; Meshram, Megha; Gopan, Amrit; Ganjewar, Vaibhav; Kumar, Praveen; Bhatia, Shobna J

    2012-06-01

    Transient lower esophageal sphincter relaxation (tLESR) and decreased basal lower esophageal sphincter (LES) pressure are postulated mechanisms of gastroesophageal reflux (GER). There is conflicting evidence on the effect of carbonated drinks on lower esophageal sphincter function. This study was conducted to assess the effect of a carbonated beverage on tLESR and LES pressure. High resolution manometry tracings (16 channel water-perfused, Trace 1.2, Hebbard, Australia) were obtained in 18 healthy volunteers (6 men) for 30 min each at baseline, and after 200 mL of chilled potable water and 200 mL of chilled carbonated cola drink (Pepsi [Pepsico India Ltd]). The sequence of administration of the drinks was determined by random number method generated by a computer. The analysis of tracings was done using TRACE 1.2 software by a physician who was unaware of the sequence of administration of fluids. The mean (SD) age of the participant was 37.3 (12.9) years. The median (range) frequency of tLESr was higher after the carbonated beverage (10.5 [0-26]) as compared to baseline (0 [0-3], p = 0.005) as well as after water (1 [0-14], p = 0.010). The LES pressure decreased after ingestion of the carbonated beverage (18.5 [11-37] mmHg) compared to baseline (40.5 [25-66] mmHg, p = 0.0001) and after water (34 [15-67] mmHg, p = 0.003). Gastric pressure was not different in the three groups. Ingestion of a carbonated beverage increases tLESr and lowers LES pressure in healthy subjects.

  1. Relaxation System

    Science.gov (United States)

    1987-01-01

    Environ Corporation's relaxation system is built around a body lounge, a kind of super easy chair that incorporates sensory devices. Computer controlled enclosure provides filtered ionized air to create a feeling of invigoration, enhanced by mood changing aromas. Occupant is also surrounded by multidimensional audio and the lighting is programmed to change colors, patterns, and intensity periodically. These and other sensory stimulators are designed to provide an environment in which the learning process is stimulated, because research has proven that while an individual is in a deep state of relaxation, the mind is more receptive to new information.

  2. [Self-reported substance abuse related emergencies: frequency and nature].

    Science.gov (United States)

    Schäfer, G; Smoltczyk, H; Dengler, W; Buchkremer, G

    2000-04-01

    The aim of this study was to estimate the frequency and nature of self-reported and drug-related emergencies. 47 patients of a ward for opiate detoxification were interviewed about their experiences with drug-related emergencies. Typical categories had to be found like overdoses, seizures, accidents and suicide attempts respectively. 68% had own experience with drug-related emergency. A majority suffered opiate overdose with different extensions as unconsciousness or breath-depression. Alcohol and polydrug use was associated with overdose. Drug-related accidents were only reported by men. Half the number of drug-related emergencies were treated in hospital. Most emergencies occurred alone either in a home environment or outside. Harm reduction interventions like observed user rooms should be established. Furthermore other strategies to reduce the number of emergencies as sharing naloxon or resuscitation programs in wards for detoxification could also be an effective method to prevent near fatal or fatal overdoses in dependent subjects.

  3. Low temperature dielectric relaxation and charged defects in ferroelectric thin films

    Directory of Open Access Journals (Sweden)

    A. Artemenko

    2013-04-01

    Full Text Available We report a dielectric relaxation in BaTiO3-based ferroelectric thin films of different composition and with several growth modes: sputtering (with and without magnetron and sol-gel. The relaxation was observed at cryogenic temperatures (T < 100 K for frequencies from 100 Hz up to 10 MHz. This relaxation activation energy is always lower than 200 meV and is very similar to the relaxation that we reported in the parent bulk perovskites. Based on our Electron Paramagnetic Resonance (EPR investigation, we ascribe this dielectric relaxation to the hopping of electrons among Ti3+-V(O charged defects. Being dependent on the growth process and on the amount of oxygen vacancies, this relaxation can be a useful probe of defects in actual integrated capacitors with no need for specific shaping.

  4. Internal protein dynamics on ps to μs timescales as studied by multi-frequency {sup 15}N solid-state NMR relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Zinkevich, Tatiana [Martin-Luther-Universität Halle-Wittenberg, NMRGroup, Faculty of Natural Sciences II, Institut für Physik (Germany); Chevelkov, Veniamin [Max-Planck-Institut für Biophysikalische Chemie (Germany); Reif, Bernd [Technische Universität München, Department Chemie (Germany); Saalwächter, Kay; Krushelnitsky, Alexey, E-mail: krushelnitsky@physik.uni-halle.de [Martin-Luther-Universität Halle-Wittenberg, NMRGroup, Faculty of Natural Sciences II, Institut für Physik (Germany)

    2013-09-19

    A comprehensive analysis of the dynamics of the SH3 domain of chicken alpha-spectrin is presented, based upon {sup 15}N T{sub 1} and on- and off-resonance T{sub 1ρ} relaxation times obtained on deuterated samples with a partial back-exchange of labile protons under a variety of the experimental conditions, taking explicitly into account the dipolar order parameters calculated from {sup 15}N–{sup 1}H dipole–dipole couplings. It is demonstrated that such a multi-frequency approach enables access to motional correlation times spanning about 6 orders of magnitude. We asses the validity of different motional models based upon orientation autocorrelation functions with a different number of motional components. We find that for many residues a “two components” model is not sufficient for a good description of the data and more complicated fitting models must be considered. We show that slow motions with correlation times on the order of 1–10 μs can be determined reliably in spite of rather low apparent amplitudes (below 1 %), and demonstrate that the distribution of the protein backbone mobility along the time scale axis is pronouncedly non-uniform and non-monotonic: two domains of fast (τ < 10{sup −10} s) and intermediate (10{sup −9} s < τ < 10{sup −7} s) motions are separated by a gap of one order of magnitude in time with almost no motions. For slower motions (τ > 10{sup −6} s) we observe a sharp ∼1 order of magnitude decrease of the apparent motional amplitudes. Such a distribution obviously reflects different nature of backbone motions on different time scales, where the slow end may be attributed to weakly populated “excited states.” Surprisingly, our data reveal no clearly evident correlations between secondary structure of the protein and motional parameters. We also could not notice any unambiguous correlations between motions in different time scales along the protein backbone emphasizing the importance of the inter

  5. Low-frequency dielectric relaxation near the Curie temperature in triglycine sulfate crystals containing radiation-induced defects and α-alanine impurity

    International Nuclear Information System (INIS)

    Bradulina, L.G.; Lotonov, A.M.; Gavrilova, N.D.

    2001-01-01

    The comparison of dielectric characteristics of the triglycine sulfate (TGS) polydomain crystal in the area of the Curie point with the parameters of the TGS monodomain crystals with the α-alanine admixture (ATGS) and gamma-irradiated TGS is carried out. No differences in the relaxation spectra of the TGS mono- and polydomain crystals is determined. The opinion is rejected, that only domain boundaries and processes, connected with the domain structure rebuilding by transition from the para- into the ferro phase, determined the character of the TGS crystal relaxation spectrum [ru

  6. Distribution of relaxation times in (KBr)/sub 0.5/(KCN)/sub 0.5/

    International Nuclear Information System (INIS)

    Birge, N.O.; Jeong, Y.H.; Nagel, S.R.; Bhattacharya, S.; Susman, S.

    1984-01-01

    Measurements of the dielectric response of (KBr)/sub 0.5/(KCN)/sub 0.5/ covering nine decades of frequency are reported. We have shown how the relaxation times proliferate as the temperature is lowered. The anomalously wide distribution of relaxation times can be generated from a Gaussian distribution of energy barriers. As temperature is decreased not only does the spread of relaxation times increase, but more importantly the width of the distribution of activation energies itself increases

  7. Relaxation effects in ferrous complexes

    International Nuclear Information System (INIS)

    Nicolini, C.; Mathieu, J.P.; Chappert, J.

    1976-01-01

    The slow relaxation mechanism of the Fe 2+ ion in the tri-fluorinated TF(acac) and hexafluorinated HF(acac) complexes of Fe(II) acetylacetonate was investigated. The 300K and 77K Moessbauer spectra for TF(acac) consist in a slightly asymmetric quadrupole doublet. On the contrary, at 4.2K the higher energy line is strongly widened; that is typical of a slowing down in the electron relaxation frequency [fr

  8. The use of (double) relaxation oscillation SQUIDs as a sensor

    NARCIS (Netherlands)

    van Duuren, M.J.; Brons, G.C.S.; Kattouw, H.; Flokstra, Jakob; Rogalla, Horst

    1997-01-01

    Relaxation Oscillation SQUIDs (ROSs) and Double Relaxation Oscillation SQUIDs (DROSs) are based on relaxation oscillations that are induced in hysteretic dc SQUIDs by an external L-R shunt. The relaxation frequency of a ROS varies with the applied flux Φ, whereas the output of a DROS is a dc

  9. Differences between food group reports of low energy reporters and non-low energy reporters on a food frequency questionnaire

    Science.gov (United States)

    Millen, Amy E.; Tooze, Janet A.; Subar, Amy F.; Kahle, Lisa L.; Schatzkin, Arthur; Krebs-Smith, Susan M.

    2013-01-01

    Background Low-energy reporters (LERs) and non-LERs differ with respect to a number of characteristics, including self-reported intake of foods. Limited data exists investigating food intake differences with LERs identified using doubly labeled water (DLW). Objective In the Observing Protein and Energy Nutrition Study (September, 1999-March, 2000), differences were examined between food group reports of LERs and non-LERs on a food frequency questionnaire (FFQ) (n=440). Design LERs were identified using DLW. LERs' (n=220) and non-LERs' (n=220) reports of 43 food groups on the FFQ were examined in three ways: whether they reported consuming a food group (yes/no), how frequently they reported consuming it (times/day), and the reported portion size (small, medium, or large). Analyses were adjusted for total energy expenditure from DLW. Results LERs compared to non-LERs were less likely to report consumption for one food group among women (soft drinks/regular) and no food groups among men. Reported mean daily frequency of consumption was lower in LERs compared to non-LERs for 23 food groups among women and 24 food groups among men (18 food groups were similar in men and women). Additionally, reported mean portion sizes were smaller for LERs compared to non-LERs for 6 food groups among women and 5 food groups among men (3 food groups were similar in men and women). Results varied minimally by sex and body mass index (BMI). Conclusions LERs as compared to non-LERs were more likely to differ regarding their reported frequency of consumption of food groups than their reported consumption (yes/no) of the food groups or the food groups' reported portion sizes. Results did not vary greatly by sex or BMI. It still remains to be known whether improvement in questionnaire design or additional tools or methods would lead to a decrease in differential reporting due to LER status on an FFQ. PMID:19559136

  10. Radio frequency superconductivity at CERN: a status report

    International Nuclear Information System (INIS)

    Arnolds-Mayer, G.; Benvenuti, C.; Bernard, P.

    1988-01-01

    Up to 1984 the efforts in superconducting (s.c.) cavity development at CERN were mainly concentrated on 500 MHz cavities, leading to the test of a 5-cell, 500 MHz cavity at PETRA. The results confirmed that the achievable accelerating fields do not decrease at lower frequencies as strongly as previously suspected. Therefore, it was decided in 1984 to concentrate efforts on 352 MHz cavities. This frequency choice is suggested by the fact that LEP will be equipped at the beginning with 128 Cu cavities at 352 MHz which will bring up energies to 55 GeV/beam [5]. There is an obvious interest to install at a later stage s.c. cavities with the same frequency and to use at maximum the existing installation of radio frequency (r.f.) power sources. With the installed r.f. power of 16 MW, LEP could be upgraded to ∼ 90 GeV by using s.c. cavities. This will require the construction, testing and installation of several hundred of s.c. cavities, therefore arguments of economy and reliability are of outstanding importance. The LEP program asks for many additional items and substantial work has gone into the development, construction and testing of cryostats, main couplers, Higher-Order Mode (HOM) couplers and frequency tuners. Besides the main line based on Nb-cavities another development has been pursued and that is the deposition of a thin niobium layer on copper cavities. Results look very promising but more efforts will be needed to reach the same level of know-how as for Nb cavities. 34 references, 7 figures, 2 tables

  11. Fast waves near the lower hybrid frequency. Final contract report

    International Nuclear Information System (INIS)

    McWilliams, R.

    1984-01-01

    The main function of this contract has been to advance the theory of fast waves near the lower hybrid frequency. Special emphasis was to be given to aspects which would assist experimentalists in planning and performing experiments to test the feasibility of using the fast wave for plasma heating and current drive. Evanescent and propagating conditions for the wave were to be determined. Possible antennas for launching the waves were to be determined. Coupling coefficients of the waves into the plasma were to be found. The results were to be applied to present day and reactor grade plasma parameters

  12. The effects of single-session music therapy interventions on the observed and self-reported levels of pain control, physical comfort, and relaxation of hospice patients.

    Science.gov (United States)

    Krout, R E

    2001-01-01

    This article describes the process and results of a three-month music therapy clinical effectiveness study conducted with terminally ill patients. The purpose of this study was to quantify and evaluate the effectiveness of single-session music therapy interventions with hospice patients in three patient problem areas: pain control; physical comfort; and relaxation. Data from a total of 90 sessions conducted with a total of 80 subjects served by Hospice of Palm Beach County, Florida, were included in the study. Music therapy services were provided by five board-certified music therapists and one music therapist eligible for board certification. The subjects in this study were receiving regularly scheduled music therapy services from the hospice organization. The study used both behavioral observation and subject's self-reporting as methods of data reporting and recording. Subjects were observed for, or self-reported, their levels of pain control, physical comfort, and relaxation, both before and after each music therapy session. The subjects were served in the environments where music therapy services would normally be delivered (i.e., home, hospital, nursing home, or inpatient acute-care unit of the hospice organization). Music therapy services included live active and passive music-based experiences. These were designed to build and to establish rapport with patient or family, to facilitate family interaction and patient control, to provide support and comfort, to facilitate relaxation, to enable reminiscence and life review, to provide a frame-work for spiritual exploration and validation, and to encourage the identification and expression of feelings of anticipatory mourning and grief. A total of six hypotheses stated that there would be significant pre- to postsession differences in each of the three variables: pain control, physical comfort, and relaxation, as measured during two different session and data collection scenarios. These scenarios included the

  13. Self-reported frequency of nurse-provided spiritual care.

    Science.gov (United States)

    Taylor, Elizabeth Johnston; Mamier, Iris; Ricci-Allegra, Patricia; Foith, Joanne

    2017-06-01

    To describe how frequently RNs provide 17 spiritual care therapeutics (or interventions) during a 72-80h timeframe. Plagued by conceptual muddiness as well as weak methods, research quantifying the frequency of spiritual care is not only methodologically limited, but also sparse. Secondary analysis of data from four studies that used the Nurse Spiritual Care Therapeutics Scale (NSCTS). Data from US American RNs who responded to online surveys about spiritual care were analyzed. The four studies included intensive care unit nurses in Ohio (n=93), hospice and palliative care nurses across the US (n=104), nurses employed in a Christian health care system (n=554), and nurses responding to an invitation to participate found on a journal website (n=279). The NSCTS mean of 38 (with a range from 17 to 79 [of 85 possible]) suggested respondents include spiritual care therapeutics infrequently in their nursing care. Particularly concerning is the finding that 17-33% (depending on NSCTS item) never completed a spiritual screening during the timeframe. "Remaining present just to show caring" was the most frequent therapeutic (3.4 on a 5-point scale); those who practiced presence at least 12 times during the timeframe provided other spiritual care therapeutics more frequently than those who offered presence less frequently. Findings affirm previous research that suggests nurses provide spiritual care infrequently. These findings likely provide the strongest evidence yet for the need to improve spiritual care education and support for nurses. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Rounding behavior in the reporting of headache frequency complicates headache chronification research.

    Science.gov (United States)

    Houle, Timothy T; Turner, Dana P; Houle, Thomas A; Smitherman, Todd A; Martin, Vincent; Penzien, Donald B; Lipton, Richard B

    2013-06-01

    To characterize the extent of measurement error arising from rounding in headache frequency reporting (days per month) in a population sample of headache sufferers. When reporting numerical health information, individuals tend to round their estimates. The tendency to round to the nearest 5 days when reporting headache frequency can distort distributions and engender unreliability in frequency estimates in both clinical and research contexts. This secondary analysis of the 2005 American Migraine Prevalence and Prevention study survey characterized the population distribution of 30-day headache frequency among community headache sufferers and determined the extent of numerical rounding ("heaping") in self-reported data. Headache frequency distributions (days per month) were examined using a simplified version of Wang and Heitjan's approach to heaping to estimate the probability that headache sufferers round to a multiple of 5 when providing frequency reports. Multiple imputation was used to estimate a theoretical "true" headache frequency. Of the 24,000 surveys, headache frequency data were available for 15,976 respondents diagnosed with migraine (68.6%), probable migraine (8.3%), or episodic tension-type headache (10.0%); the remainder had other headache types. The mean number of headaches days/month was 3.7 (standard deviation = 5.6). Examination of the distribution of headache frequency reports revealed a disproportionate number of responses centered on multiples of 5 days. The odds that headache frequency was rounded to 5 increased by 24% with each 1-day increase in headache frequency (odds ratio: 1.24, 95% confidence interval: 1.23 to 1.25), indicating that heaping occurs most commonly at higher headache frequencies. Women were more likely to round than men, and rounding decreased with increasing age and increased with symptoms of depression. Because of the coarsening induced by rounding, caution should be used when distinguishing between episodic and chronic

  15. Craniosacral therapy as a relaxation method for hyperreactivity in a child with sensory integration disorder – a case report

    Directory of Open Access Journals (Sweden)

    Katarzyna Strojek

    2017-06-01

    Full Text Available Impaired sensory processing, the so-called sensory integration disorder, occurs when the brain is unable to correctly process the stimuli coming from the internal and the external environment. Proper sensory integration allows the child for normal everyday functioning (learning, playing, resting, whereas children with impaired sensory integration often lack the psycho-affective balance. They suffer from psychosomatic disorders, which may be caused by e.g. stress due to peer competition at school. Children affected by this disorder need relaxation to regain the balance necessary for proper physical and mental development. The aim of the study is to assess the therapeutic outcomes in a 7-year-old girl diagnosed with vestibular, tactile and proprioceptive deficits. Craniosacral therapy and somatosensory integration method were used. Relaxation therapy had beneficial effects on child’s development, behaviour and the manner of communication with the environment. The hyperesthesia sites, which were present before the therapy, resolved. Previously reported self-aggressive behaviours are no longer observed. Furthermore, the child’s independence, which is crucial for the psychosocial development, also increased during the therapy.

  16. Breathing and Relaxation

    Science.gov (United States)

    ... Find a Doctor Relaxation is the absence of tension in muscle groups and a minimum or absence ... Drill Meditation Progressive Muscle Relaxation Minimizing Shortness of Breath Visualization This information has been approved by Shelby ...

  17. Intra-well relaxation process in magnetic fluids subjected to strong polarising fields

    Energy Technology Data Exchange (ETDEWEB)

    Marin, C.N., E-mail: cmarin@physics.uvt.ro [West University of Timisoara, Faculty of Physics, B-dul V. Parvan, No. 4, Timisoara 300223 (Romania); Fannin, P.C. [Department of Electronic and Electrical Engineering, Trinity College, Dublin 2 (Ireland); Malaescu, I.; Barvinschi, P.; Ercuta, A. [West University of Timisoara, Faculty of Physics, B-dul V. Parvan, No. 4, Timisoara 300223 (Romania)

    2012-02-15

    We report on the frequency and field dependent complex magnetic susceptibility measurements of a kerosene-based magnetic fluid with iron oxide nanoparticles, stabilized with oleic acid, in the frequency range 0.1-6 GHz and over the polarising field range of 0-168.4 kA/m. By increasing polarising field, H, a subsidiary loss-peak clearly occurs in the vicinity of the ferromagnetic resonance peak, from which it remains distinct even in strong polarising fields of 168.4 kA/m. This is in contrast to other reported cases in which the intra-well relaxation process is manifested only as a shoulder of the resonance peak, which vanishes in polarising fields larger than that of 100 kA/m. The results of the XRD analysis connected to the anisotropy field results confirm that the investigated sample contains particles of magnetite and of the tetragonal phase of maghemite. Taking into account the characteristics of our sample, the theoretical analysis revealed that the intra-well relaxation process of the small particles of the tetragonal phase of maghemite may be responsible for the subsidiary loss peak of the investigated magnetic fluid. - Highlights: > Intra-well relaxation process in a magnetic fluid is studied. > Sample consists of the tetragonal phase of maghemite and magnetite particles. > A subsidiary relaxation peak is observed in the vicinity of the resonance peak. > Relaxation peak is correlated to the intra-well relaxation process. > It is assigned to the tetragonal phase of maghemite particles.

  18. Extremely low frequencies. Health effects of extremely low frequency electromagnetic fields. Opinion of the Afsset. Collective expertise report

    International Nuclear Information System (INIS)

    Bounouh, Alexandre; Brugere, Henri; Clavel, Jacqueline; Febvre, Pascal; Lagroye, Isabelle; Vecchia, Paolo; Dore, Jean-Francois; Anfosso-Ledee, Fabienne; Berengier, Michel; Cesarini, Jean-Pierre; Cohen, Jean-Claude; Planton, Serge; Courant, Daniel; Tardif, Francois; Couturier, Frederic; Debouzy, Jean-Claude; El Khatib, Aicha; Flahaut, Emmanuel; Gaffet, Eric; Hours, Martine; Lambert, Jacques; Vallet, Michel; Job, Agnes; Labeyrie, Antoine; Laurier, Dominique; Le Bihan, Olivier; Lepoutre, Philippe; Marchal, Didier; Moch, Annie; Pirard, Philipe; Rumeau, Michel; De Seze, Rene; Attia, Dina; Merckel, Olivier; Fite, Johanna; Guichard, Alexandra; Saihi, Myriam; Guitton, Sophie; Saddoki, Sophia

    2010-03-01

    This report aims at proposing a synthesis of works of international expertise on the health effect of extremely low frequency electromagnetic fields, at performing a methodological analysis of the 'Expers' study (a study on the exposure of individuals), at performing a methodological analysis of a study performed by the Criirem in the western part of France, at assessing the contribution of different equipment and situations to the exposure of population to extremely-low-frequency electromagnetic fields, at making recommendations and proposals for a better assessment of the exposure level, and at proposing topics of investigation and research to improve knowledge on these issues. The report recalls the context, scope and modalities of the study, gives an overview of generalities on electromagnetic fields (nature, physical values, electromagnetic spectrum, artificial and natural electromagnetic field sources, exposure threshold values and regulatory context), addresses the assessment of exposure (notion of exposure, exposure assessment methods, analysis of available data, analysis of recent or current studies), gives an overview of biological and health effects of these electromagnetic fields (methodological aspects, interaction between fields and biological tissues, synthesis of the international expertise on health impacts). Recommendations are formulated

  19. The origin of small and large molecule behavior in the vibrational relaxation of highly excited molecules

    International Nuclear Information System (INIS)

    Gordon, R.J.

    1990-01-01

    An explanation is proposed for the qualitatively different types of behavior that have been reported for the vibrational relaxation of highly excited diatomic and polyatomic molecules. It is argued that all of the diatomic molecules that have been studied in bulk relax adiabatically at room temperature. In contrast, large polyatomic molecules have low frequency modes which act at ''doorway'' modes for the rest of the molecules, producing an impulsive relaxation mechanism. The theoretical work of Nesbitt and Hynes showed that impulsive collisions result in an exponential decay of the average vibrational energy of a Morse oscillator, whereas adiabatic collisions produce nonexponential power law behavior. We propose that this result explains a large body of data for the vibrational relaxation of small and large molecules

  20. Report on cascade energy relaxation from PVP to Tb3+:Bi2SiO5 nanophosphor through salicylic acid in composite polymeric film

    Science.gov (United States)

    Kumari, Pushpa; Dwivedi, Y.

    2018-05-01

    The present article reports structural and spectroscopic properties of Tb:Bi2SiO5 nanophosphors dispersed in Polyvinylpyrrolidone polymer film, in presence of Salicylic acid (SA) molecule, which acts as a sensitizer. Detailed structural and spectroscopic characterizations were carried out using X-ray diffraction patterns, Scanning Electron Microscope, Fourier Transform Infrared and Excitation and photoluminescence techniques. The mean crystallite size of Tb3+:Bi2SiO5 nanophosphor and Tb3+:Bi2SiO5 in Polyvinylpyrrolidone polymer composite was estimated ∼22 nm and ∼28 nm, respectively. We have report atleast two times enhancement in Tb3+ ions emission intensity due to the efficient energy transfer from salicylic acid molecule to Tb ions. In addition to energy transfer from salicylic acid, the Polyvinylpyrrolidone polymeric host was also reported to serve as a sensitizer for SA molecule and Tb3+ ions through a cascade energy relaxation process while exciting with 248 nm photons. On 248 nm photon excitation, atleast five improvements in Tb3+ ion emission intensity are reported. Presence of SA molecule facilitates precise colour tuning as obvious from the CIE coordinates.

  1. Relative frequency and estimated minimal frequency of Lysosomal Storage Diseases in Brazil: Report from a Reference Laboratory

    Directory of Open Access Journals (Sweden)

    Roberto Giugliani

    2017-03-01

    Full Text Available Abstract Lysosomal storage diseases (LSDs comprise a heterogeneous group of more than 50 genetic conditions of inborn errors of metabolism (IEM caused by a defect in lysosomal function. Although there are screening tests for some of these conditions, diagnosis usually depends on specific enzyme assays, which are only available in a few laboratories around the world. A pioneer facility for the diagnosis of IEM and LSDs was established in the South of Brazil in 1982 and has served as a reference service since then. Over the past 34 years, samples from 72,797 patients were referred for investigation of IEM, and 3,211 were confirmed as having an LSD (4.41%, or 1 in 22, with 3,099 of these patients originating from Brazil. The rate of diagnosis has increased over time, in part due to the creation of diagnostic networks involving a large number of Brazilian services. These cases, referred from Brazilian regions, provide insight about the relative frequency of LSDs in the country. The large amount of data available allows for the estimation of the minimal frequency of specific LSDs in Brazil. The reported data could help to plan health care policies, as there are specific therapies available for most of the cases diagnosed.

  2. {sup 13}C relaxation in an RNA hairpin

    Energy Technology Data Exchange (ETDEWEB)

    King, G.C. [Univ. of South Wales, Kensington (Australia)]|[Rice Univ., Houston, TX (United States); Akratos, C. [Univ. of South Wales, Kensington (Australia); Xi, Z.; Michnica, M.J. [Rice Univ., Houston, TX (United States)

    1994-12-01

    This initial survey of {sup 13}C relaxation in the {triangle}TAR RNA element has generated a number of interesting results that should prove generally useful for future studies. The most readily comparable study in the literature monitored {sup 13}C relaxation of the methyl groups from unusual bases in tRNA{sup Phe}. The study, which used T{sub 1} and NOE data only, reported order parameters for the methyl group axis that ranged between 0.51 and 0.97-a range similar to that observed here. However, they reported a breakdown of the standard order parameter analysis at higher (118-MHz {sup 13}C) frequencies, which should serve to emphasize the need for a thorough exploration of suitable motional models.

  3. Frequency, stability and differentiation of self-reported school fear and truancy in a community sample

    OpenAIRE

    Steinhausen, Hans-Christoph; Müller, Nora; Metzke, Christa Winkler

    2008-01-01

    Abstract Background Surprisingly little is known about the frequency, stability, and correlates of school fear and truancy based on self-reported data of adolescents. Methods Self-reported school fear and truancy were studied in a total of N = 834 subjects of the community-based Zurich Adolescent Psychology and Psychopathology Study (ZAPPS) at two times with an average age of thirteen and sixteen years. Group definitions were based on two behavioural items of the Youth Self-Report (YSR). Comp...

  4. Mechanical relaxation in glasses

    International Nuclear Information System (INIS)

    Hiki, Y.

    2004-01-01

    The basic properties of glasses and the characteristics of mechanical relaxation in glasses were briefly reviewed, and then our studies concerned were presented. Experimental methods adopted were viscosity, internal friction, ultrasonic attenuation, and Brillouin scattering measurements. The specimens used were several kinds of inorganic, organic, and metallic glasses. The measurements were mainly carried out from the room temperature up to the glass transition temperature, and the relaxation time was determined as a function of temperature. The 'double relaxation' composed of two Arrhenius-type relaxations was observed in many materials. In both relaxations, the 'compensation effect' showing a correlation of the pre-exponential factor and the activation energy was observed. These results were explained by considering the 'complex relaxation' due to cooperative motions of atoms or group of atoms. Values of activation energy near the glass transition determined by the various experimental methods were compared with each other

  5. Nuclear relaxation and critical fluctuations in membranes containing cholesterol

    Science.gov (United States)

    McConnell, Harden

    2009-04-01

    Nuclear resonance frequencies in bilayer membranes depend on lipid composition. Our calculations describe the combined effects of composition fluctuations and diffusion on nuclear relaxation near a miscibility critical point. Both tracer and gradient diffusion are included. The calculations involve correlation functions and a correlation length ξ =ξ0T/(T -Tc), where T -Tc is temperature above the critical temperature and ξ0 is a parameter of molecular length. Several correlation functions are examined, each of which is related in some degree to the Ising model correlation function. These correlation functions are used in the calculation of transverse deuterium relaxation rates in magic angle spinning and quadrupole echo experiments. The calculations are compared with experiments that report maxima in deuterium and proton nuclear relaxation rates at the critical temperature [Veatch et al., Proc. Nat. Acad. Sci. U.S.A. 104, 17650 (2007)]. One Ising-model-related correlation function yields a maximum 1/T2 relaxation rate at the critical temperature for both magic angle spinning and quadrupole echo experiments. The calculated rates at the critical temperature are close to the experimental rates. The rate maxima involve relatively rapid tracer diffusion in a static composition gradient over distances of up to 10-100 nm.

  6. CNV amplitude as a neural correlate for stuttering frequency: A case report of acquired stuttering.

    Science.gov (United States)

    Vanhoutte, Sarah; Van Borsel, John; Cosyns, Marjan; Batens, Katja; van Mierlo, Pieter; Hemelsoet, Dimitri; Van Roost, Dirk; Corthals, Paul; De Letter, Miet; Santens, Patrick

    2014-11-01

    A neural hallmark of developmental stuttering is abnormal articulatory programming. One of the neurophysiological substrates of articulatory preparation is the contingent negative variation (CNV). Unfortunately, CNV tasks are rarely performed in persons who stutter and mainly focus on the effect of task variation rather than on interindividual variation in stutter related variables. However, variations in motor programming seem to be related to variation in stuttering frequency. The current study presents a case report of acquired stuttering following stroke and stroke related surgery in the left superior temporal gyrus. A speech related CNV task was administered at four points in time with differences in stuttering severity and frequency. Unexpectedly, CNV amplitudes at electrode sites approximating bilateral motor and left inferior frontal gyrus appeared to be inversely proportional to stuttering frequency. The higher the stuttering frequency, the lower the activity for articulatory preparation. Thus, the amount of disturbance in motor programming seems to determine stuttering frequency. At right frontal electrodes, a relative increase in CNV amplitude was seen at the test session with most severe stuttering. Right frontal overactivation is cautiously suggested to be a compensation strategy. In conclusion, late CNV amplitude elicited by a relatively simple speech task seems to be able to provide an objective, neural correlate of stuttering frequency. The present case report supports the hypothesis that motor preparation has an important role in stuttering. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Relaxation characteristics of hastelloy X

    International Nuclear Information System (INIS)

    Suzuki, Kazuhiko

    1980-02-01

    Relaxation diagrams of Hastelloy X (relaxation curves, relaxation design diagrams, etc.) were generated from the creep constitutive equation of Hastelloy X, using inelastic stress analysis code TEPICC-J. These data are in good agreement with experimental relaxation data of ORNL-5479. Three typical inelastic stress analyses were performed for various relaxation behaviors of the high-temperature structures. An attempt was also made to predict these relaxation behaviors by the relaxation curves. (author)

  8. The ultrasonic relaxation spectra for furfural molecules undergoing conformational changes

    International Nuclear Information System (INIS)

    Mirzaev, S. Z.; Telyaev, S. Q.; Egamberdiev, K.

    2011-01-01

    The acoustic spectra of liquid furfural have been investigated in the frequency range from 0.1MHz to 150 MHz and at the temperatures from 303.15 K to 333.15 K. The ultrasonic spectra of pure furfural show two relaxation processes. One relaxation process is located in the frequency range ∼0.2 MHz, and the second in the frequency range ∼2 MHz. The process with the lower relaxation frequency has been assigned to the 'X0-cis and X0-trans' internal rotation of furfural molecules. (authors)

  9. Relaxation towards phase-locked dynamics in long Josephson junctions

    DEFF Research Database (Denmark)

    Salerno, M.; Grønbech-Jensen, Niels; Samuelsen, Mogens Rugholm

    1995-01-01

    We study the relaxation phenomenon towards phase-locked dynamics in long Josephson junctions. In particular the dependence of the relaxation frequency for the equal time of flight solution on the junction parameters is derived. The analysis is based on a phase-locked map and is compared with direct...... numerical experiments performed both on the map and on the perturbed sine-Gordon equation. As an interesting result we find that very close to a bifurcation the relaxation frequency is exactly equal to the half of the step frequency, i.e., the frequency characterizing the period-one solution....

  10. Segmental dynamics in polymer melts by relaxation techniques and quasielastic neutron scattering

    Science.gov (United States)

    Colmenero, J.

    1993-01-01

    The dynamics of the segmental α-relaxation in three different polymeric systems, poly(vinyl methy ether) (PVME), poly(vinyl chloride) (PVC) and poly(bisphenol A, 2-hydroxypropylether) (PH) has been studied by means of relaxation techniques and quasielastic neutron scattering (backscattering spectrometers IN10 and IN13 at the ILL-Grenoble). By using these techniques we have covered a wide timescale ranging from mesoscopic to macroscopic times (10-10-101s). For analyzing the experimental data we have developed a phenomenological procedure in the frequency domain based on the Havriliak-Negami relaxation function which in fact implies a Kohlrausch-Williams-Watts relaxation function in the time domain. The results obtained indicate that the dynamics of the α-relaxation in a wide timescale shows a clear non-Debye behaviour. The shape of the relaxation function is found to be similar for the different techniques used and independent of temperature and momentum transfer (Q). Moreover the characteristic relaxation times deduced from the fitting of the experimental data can also be described using only one Vogel-Fulcher functional form. Besides we found that the Q-dependence of the relaxation times obtained by QENS is given by a power law, τ(Q) propto Q-n (n > 2) n being dependent on the system, and that the Q-behaviour and the non-Debye behaviour are directly correlated. We discuss this correlation taking into account several data of the dynamics of the α-relaxation previously reported in the literature. We also outline a possible scenario for explaining this empirical correlation.

  11. Partner wealth predicts self-reported orgasm frequency in a sample of Chinese women

    NARCIS (Netherlands)

    Pollet, T.V.; Nettle, D.

    There has been considerable speculation about the adaptive significance of the human female orgasm, with one hypothesis being that it promotes differential affiliation or conception with high-quality males. We investigated the relationship between women's self-reported orgasm frequency and the

  12. Occupational blood exposure among health care workers: I. Frequency and reporting

    DEFF Research Database (Denmark)

    Nelsing, S; Nielsen, T L; Nielsen, Jens Ole

    1993-01-01

    The frequency and reporting rate concerning occupational blood exposure were investigated among former and currently employed medical staff at a Department of Infectious Diseases (DID) having a high prevalence of HIV-positive patients. Subjects were asked to complete an anonymous questionnaire de...

  13. High frequency microphone measurements for transition detection on airfoils. NACA-0015 appendix report

    DEFF Research Database (Denmark)

    Døssing, Mads

    Time series of pressure fluctuations has been obtained using high frequency microphones distributed over the surface of airfoils undergoing wind tunnel tests in the LM Windtunnel, owned by ’LM Glasfiber’, Denmark. The present report describes the dataanalysis, with special attention given to tran...

  14. TEACHING NEUROMUSCULAR RELAXATION.

    Science.gov (United States)

    NORRIS, JEANNE E.; STEINHAUS, ARTHUR H.

    THIS STUDY ATTEMPTED TO FIND OUT WHETHER (1) THE METHODS FOR ATTAINING NEUROMUSCULAR RELAXATION THAT HAVE PROVED FRUITFUL IN THE ONE-TO-ONE RELATIONSHIP OF THE CLINIC CAN BE SUCCESSFULLY ADAPTED TO THE TEACHER-CLASS RELATIONSHIP OF THE CLASSROOM AND GYMNASIUM, AND (2) NEUROMUSCULAR RELAXATION CAN BE TAUGHT SUCCESSFULLY BY AN APPROPRIATELY TRAINED…

  15. Relaxation of Anisotropic Glasses

    DEFF Research Database (Denmark)

    Deubener, Joachim; Martin, Birgit; Wondraczek, Lothar

    2004-01-01

    . When the load was removed at room temperature a permanent optical anisotropy (birefringence) was observed only perpendicular to cylinder axis and the pressure direction indicating complete elimination of thermal stresses. Relaxation of structural anisotropy was studied from reheating experiments using...... the energy release, thermo-mechanical and optical relaxation behaviour are drawn....

  16. Relaxation techniques for stress

    Science.gov (United States)

    ... raise your heart rate. This is called the stress response. Relaxation techniques can help your body relax and lower your blood pressure ... also many other types of breathing techniques you can learn. In many cases, you do not need much ... including those that cause stress. Meditation has been practiced for thousands of years, ...

  17. Board meeting frequency and corporate social responsibility (CSR reporting: Evidence from Malaysia

    Directory of Open Access Journals (Sweden)

    Nurulyasmin Binti Ju Ahmad

    2017-05-01

    Full Text Available This study aims at determining the effectiveness of board meeting frequency on Corporate Social Responsibility (CSR reporting by public listed companies on the Main Market of Bursa Malaysia. A CSR reporting index consisting of 51 items was developed based on six themes: General, Community, Environment, Human Resource, Marketplace and Other. A content analysis was used to determine the extent of CSR reporting. An Ordinary Least Square (OLS regression was employed in determining the association between board meeting frequency and CSR reporting. The finding of the study is that advising tendency (frequency of board meetings is not associated with CSR reporting. Overall this study strengthens the idea that advising tendency of the board is essential to companies in order to safeguard all stakeholders’ interests. Accordingly, regulators and policymakers should be more stringent in monitoring company’s conformance towards regulations. This study provides a new avenue of knowledge and contributes to the literature on the practices of the board of directors and corporate social responsibility reporting in the context of a semi-developed country

  18. About relaxation phenomena and transport processing in a fully ionized non-ideal plasma

    International Nuclear Information System (INIS)

    Baimbetov, F.B.; Iztleuov, N.T.

    1999-01-01

    In this report correlation effects for non-ideal plasma are accounted in the so called pseudopotentials. The accounting of high order correlation influences in the pseudopotential lead to the strongly screened potential. Kinetic equation with pseudopotential is cited. The equations which describe the relaxation of the difference of directed velocities of plasma particles, and frequency of particle collision which determines relaxation of temperature for non-ideal plasma are obtained. On basis of mentioned kinetic equation the transport equation is obtained as well

  19. Nonmonotonic low frequency losses in HTSCs

    International Nuclear Information System (INIS)

    Castro, H; Gerber, A; Milner, A

    2007-01-01

    A calorimetric technique has been used in order to study ac-field dissipation in ceramic BSCCO samples at low frequencies between 0.05 and 250 Hz, at temperatures from 65 to 90 K. In contrast to previous studies, where ac losses have been reported with a linear dependence on magnetic field frequency, we find a nonmonotonic function presenting various maxima. Frequencies corresponding to local maxima of dissipation depend on the temperature and the amplitude of the ac magnetic field. Flux creep is argued to be responsible for this behaviour. A simple model connecting the characteristic vortex relaxation times (flux creep) and the location of dissipation maxima versus frequency is proposed

  20. Dielectric relaxation in AgI doped silver selenomolybdate glasses

    Science.gov (United States)

    Palui, A.; Shaw, A.; Ghosh, A.

    2016-05-01

    We report the study of dielectric properties of some silver ion conducting silver selenomolybdate mixed network former glasses in a wide frequency and temperature range. The experimental data have been analyzed in the framework of complex dielectric permittivity. The dielectric permittivity data have been well interpreted using the Cole-Cole function. The temperature dependence of relaxation time obtained from real part of dielectric permittivity data shows an Arrhenius behavior. The activation energy shows a decreasing trend with the increase of doping content. Values of stretched exponential parameter are observed to be independent of temperature and composition.

  1. The relaxation time approximation

    International Nuclear Information System (INIS)

    Gairola, R.P.; Indu, B.D.

    1991-01-01

    A plausible approximation has been made to estimate the relaxation time from a knowledge of the transition probability of phonons from one state (r vector, q vector) to other state (r' vector, q' vector), as a result of collision. The relaxation time, thus obtained, shows a strong dependence on temperature and weak dependence on the wave vector. In view of this dependence, relaxation time has been expressed in terms of a temperature Taylor's series in the first Brillouin zone. Consequently, a simple model for estimating the thermal conductivity is suggested. the calculations become much easier than the Callaway model. (author). 14 refs

  2. Nonmaxwell relaxation in disordered media: Physical mechanisms and fractional relaxation equations

    International Nuclear Information System (INIS)

    Arkhincheev, V.E.

    2004-12-01

    The problem of charge relaxation in disordered systems has been solved. It is shown, that due to the inhomogeneity of the medium the charge relaxation has a non-Maxwell character. The two physical mechanisms of a such behavior have been founded. The first one is connected with the 'fractality' of conducting ways. The second mechanism of nonexponential non-Maxwell behavior is connected with the frequency dispersion of effective conductivity of heterogeneous medium, initially consisting of conducting phases without dispersion. The new generalized relaxation equations in the form of fractional temporal integro-differential equations are deduced. (author)

  3. Improved memristor-based relaxation oscillator

    KAUST Repository

    Mosad, Ahmed G.

    2013-09-01

    This paper presents an improved memristor-based relaxation oscillator which offers higher frequency and wider tunning range than the existing reactance-less oscillators. It also has the capability of operating on two positive supplies or alternatively a positive and negative supply. Furthermore, it has the advantage that it can be fully integrated on-chip providing an area-efficient solution. On the other hand, The oscillation concept is discussed then a complete mathematical analysis of the proposed oscillator is introduced. Furthermore, the power consumption of the new relaxation circuit is discussed and validated by the PSPICE circuit simulations showing an excellent agreement. MATLAB results are also introduced to demonstrate the resistance range and the corresponding frequency range which can be obtained from the proposed relaxation oscillator. © 2013 Elsevier Ltd.

  4. Structural relaxation monitored by instantaneous shear modulus

    DEFF Research Database (Denmark)

    Olsen, Niels Boye; Dyre, Jeppe; Christensen, Tage Emil

    1998-01-01

    time definition based on a recently proposed expression for the relaxation time, where G [infinity] reflects the fictive temperature. All parameters entering the reduced time were determined from independent measurements of the frequency-dependent shear modulus of the equilibrium liquid....

  5. Mozart versus new age music: relaxation states, stress, and ABC relaxation theory.

    Science.gov (United States)

    Smith, Jonathan C; Joyce, Carol A

    2004-01-01

    Smith's (2001) Attentional Behavioral Cognitive (ABC) relaxation theory proposes that all approaches to relaxation (including music) have the potential for evoking one or more of 15 factor-analytically derived relaxation states, or "R-States" (Sleepiness, Disengagement, Rested / Refreshed, Energized, Physical Relaxation, At Ease/Peace, Joy, Mental Quiet, Childlike Innocence, Thankfulness and Love, Mystery, Awe and Wonder, Prayerfulness, Timeless/Boundless/Infinite, and Aware). The present study investigated R-States and stress symptom-patterns associated with listening to Mozart versus New Age music. Students (N = 63) were divided into three relaxation groups based on previously determined preferences. Fourteen listened to a 28-minute tape recording of Mozart's Eine Kleine Nachtmusik and 14 listened to a 28-minute tape of Steven Halpern's New Age Serenity Suite. Others (n = 35) did not want music and instead chose a set of popular recreational magazines. Participants engaged in their relaxation activity at home for three consecutive days for 28 minutes a session. Before and after each session, each person completed the Smith Relaxation States Inventory (Smith, 2001), a comprehensive questionnaire tapping 15 R-States as well as the stress states of somatic stress, worry, and negative emotion. Results revealed no differences at Session 1. At Session 2, those who listened to Mozart reported higher levels of At Ease/Peace and lower levels of Negative Emotion. Pronounced differences emerged at Session 3. Mozart listeners uniquely reported substantially higher levels of Mental Quiet, Awe and Wonder, and Mystery. Mozart listeners reported higher levels, and New Age listeners slightly elevated levels, of At Ease/Peace and Rested/Refreshed. Both Mozart and New Age listeners reported higher levels of Thankfulness and Love. In summary, those who listened to Mozart's Eine Kleine Nachtmusik reported more psychological relaxation and less stress than either those who listened to

  6. Optimal relaxed causal sampler using sampled-date system theory

    NARCIS (Netherlands)

    Shekhawat, Hanumant; Meinsma, Gjerrit

    This paper studies the design of an optimal relaxed causal sampler using sampled data system theory. A lifted frequency domain approach is used to obtain the existence conditions and the optimal sampler. A state space formulation of the results is also provided. The resulting optimal relaxed causal

  7. Frequency of reporting and predictive factors for anxiety and depression in patients with advanced cancer.

    Science.gov (United States)

    Salvo, N; Zeng, L; Zhang, L; Leung, M; Khan, L; Presutti, R; Nguyen, J; Holden, L; Culleton, S; Chow, E

    2012-03-01

    The prevalence of anxiety and depression in patients with advanced cancer has been reported to be on average 25% and to significantly affect patients' quality of life. Despite high prevalence rates, these disorders remain underdiagnosed and undertreated. The purpose of our study was to examine the self-report rates of anxiety and depression with the Edmonton Symptom Assessment System (ESAS) and to assess the predictive factors for these reports in cancer patients with metastatic disease. Consecutive patients who attended the Rapid Response Radiotherapy Program (RRRP) completed the ESAS as well as baseline demographic information. Ordinal logistic regression analysis was used to determine factors that significantly predicted anxiety and/or depression. Pearson χ(2) was used to test goodness-of-fit for categorical variables and established whether or not an observed frequency distribution differed from a predicted frequency distribution. A univariate analysis was conducted first and those variables with a P valueanalysis. A score test was used to test the proportional odds assumption. In total, 1439 patients seen in the RRRP between January 1999 and October 2009 completed ESAS questionnaires. Fifty-five per cent of patients reported at least mild symptoms of depression and 65% reported at least mild anxiety. In the univariate analysis, patients who were female, who had a lower performance status score, or primary lung cancer were more likely to report depressed and anxious feelings. Primary prostate cancer patients were significantly less likely to report depression and anxiety. Patients referred for spinal cord compression were significantly less depressed. The multivariate models showed that younger patients were significantly more anxious than older patients and females reported more anxiety than males. Patients who reported higher feelings of nausea, tiredness, drowsiness, dyspnoea, and worse appetite and overall well-being on the ESAS tool were more likely to

  8. Frequency, stability and differentiation of self-reported school fear and truancy in a community sample

    Directory of Open Access Journals (Sweden)

    Metzke Christa

    2008-07-01

    Full Text Available Abstract Background Surprisingly little is known about the frequency, stability, and correlates of school fear and truancy based on self-reported data of adolescents. Methods Self-reported school fear and truancy were studied in a total of N = 834 subjects of the community-based Zurich Adolescent Psychology and Psychopathology Study (ZAPPS at two times with an average age of thirteen and sixteen years. Group definitions were based on two behavioural items of the Youth Self-Report (YSR. Comparisons included a control group without indicators of school fear or truancy. The three groups were compared across questionnaires measuring emotional and behavioural problems, life-events, self-related cognitions, perceived parental behaviour, and perceived school environment. Results The frequency of self-reported school fear decreased over time (6.9 vs. 3.6% whereas there was an increase in truancy (5.0 vs. 18.4%. Subjects with school fear displayed a pattern of associated internalizing problems and truants were characterized by associated delinquent behaviour. Among other associated psychosocial features, the distress coming from the perceived school environment in students with school fear is most noteworthy. Conclusion These findings from a community study show that school fear and truancy are frequent and display different developmental trajectories. Furthermore, previous results are corroborated which are based on smaller and selected clinical samples indicating that the two groups display distinct types of school-related behaviour.

  9. The frequency of diagnostic errors in radiologic reports depends on the patient's age

    International Nuclear Information System (INIS)

    Diaz, Sandra; Ekberg, Olle

    2010-01-01

    Background: Patients who undergo treatment may suffer preventable medical errors. Some of these errors are due to diagnostic imaging procedures. Purpose: To compare the frequency of diagnostic errors in different age groups in an urban European population. Material and Methods: A total of 19 129 reported radiologic examinations were included. During a 6-month period, the analyzed age groups were: children (aged 0-9 years), adults (40-49 years), and elderly (86-95 years). Results: The frequency of radiologic examinations per year was 0.3 in children, 0.6 in adults, and 1.1 in elderly. Significant errors were significantly more frequent in the elderly (1.7%) and children (1.4%) compared with adults (0.8%). There were 60 false-positive reports and 232 false-negative reports. Most errors were made by staff radiologists after hours when they reported on examinations outside their area of expertise. Conclusion: Diagnostic errors are more frequent in children and the elderly compared with middle-aged adults

  10. Congruence in reported frequency of parent-adolescent sexual health communication: A study from Mexico.

    Science.gov (United States)

    Atienzo, Erika E; Ortiz-Panozo, Eduardo; Campero, Lourdes

    2015-08-01

    Most studies on parent-adolescent sexual health communication come from developed countries and are based on either parents' or children's reports. In developing countries, there is little evidence about the agreement among reports of all parties involved in parent-adolescent sexual health communication. The objective of this study is to explore the congruence (agreement) between adolescents and their parents about how frequently they discuss on selected sexual health topics. A total of 1606 parent-adolescent dyads of adolescents attending the first year in public high schools and their parents, in Morelos, Mexico were sampled in this study. The participants completed a self-administered questionnaire that included the frequency of parent-adolescent communication about eight sexual health topics. An ordinal logistic threshold model was used to estimate intra-class correlation coefficients within parent-adolescent dyads (as a measure of congruence) and to test if thresholds were equal between parents and adolescents. Congruence in reported frequency of parent-adolescent sexual health communication ranged from 0.205 (menstruation) to 0.307 (condoms) for mother-adolescent dyads, and from 0.103 (ejaculation) to 0.380 (condoms) for father-adolescent dyads. The thresholds (i.e., the cutoff points that define the categories in the observed ordinal variable) differed between parents and adolescents for each of the sexual health topics explored (pcongruence between parents' and adolescents' reports on parent-adolescent sexual health communication. This might be due to interpretation of frequency and intensity of sexual health communication which differs between parents and adolescents.

  11. High frequency dielectric reference materials BCR projekt 43. Final report of phase 1

    International Nuclear Information System (INIS)

    Chantry, G.

    1980-01-01

    The Group of High Frequency Specialists from Belgium, France, Germany, The Netherlands and the UK, was awarded contracts in 1975 to carry out a programme of measurements on the high frequency dielectric properties of materials. The object of this first phase of a projected three phase programme was to establish the reliability of existing methods of measurement and to examine the possibilities of specifying and producing some standard reference materials, both liquid and solid, which could be used for calibrating and checking the performance of industrial measurement equipment. The liquids chosen for the first phase were cyclohexane, cis and trans decalin, chlorobenzene and 0.1, 1, and 10% solutions of chlorobenzene in cyclohexane. Each group had a limited frequency range over which it could make meaningful measurements but there was sufficient overlap to ensure that all random and systematic errors could be quantitatively assayed. The real (epsilon') and imaginary (epsilon'') components of the complex permittivity for all the liquids were measured over the frequency range 10 - 3,000 GHz and for the two most lossy liquids (chlorobenzene and 10% chlorobenzene in cyclohexane) this range was extended downwards to one GHz. The programme established for the first time the possible experimental imprecisions to be expected in high frequency dielecric measurements and showed that the chosen liquids could be useful standard reference materials if sufficiently pure specimens could be obtained commercially at a reasonable price. The programme did however reveal an unexpected snag in that the liquids, especially cyclohexane, were found to be rather more liable to contamination than expected. Since cyclohexane is a very low-loss liquid, only a small amount of a lossy contaminant need be absorbed to make the observed loss increase dramatically. This report contains all the measured results in both tabular and graphical form and in addition full technical details are given of the

  12. Vibrational relaxation in OCS mixtures

    International Nuclear Information System (INIS)

    Simpson, C.J.S.M.; Gait, P.D.; Simmie, J.M.

    1976-01-01

    Experimental measurements are reported of vibrational relaxation times which may be used to show whether there is near resonant vibration-rotation energy transfer between OCS and H 2 , D 2 or HD. Vibrational relaxation times have been measured in OCS and OCS mixtures over the temperature range 360 to 1000 K using a shock tube and a laser schlieren system. The effectiveness of the additives in reducing the relaxation time of OCS is in the order 4 He 3 He 2 2 and HD. Along this series the effect of an increase in temperature changes from the case of speeding up the rate with 4 He to retarding it with D 2 , HD and H 2 . There is no measurable difference in the effectiveness of n-D 2 and o-D 2 and little, or no, difference between n-H 2 and p-H 2 . Thus the experimental results do not give clear evidence for rotational-vibration energy transfer between hydrogen and OCS. This contrasts with the situation for CO 2 + H 2 mixtures. (author)

  13. Enhanced AC conductivity and dielectric relaxation properties of polypyrrole nanoparticles irradiated with Ni12+ swift heavy ions

    International Nuclear Information System (INIS)

    Hazarika, J.; Kumar, A.

    2014-01-01

    In this paper, we report the 160 MeV Ni 12+ swift heavy ions (SHIs) irradiation effects on AC conductivity and dielectric relaxation properties of polypyrrole (PPy) nanoparticles in the frequency range of 42 Hz–5 MHz. Four ion fluences of 5 × 10 10 , 1 × 10 11 , 5 × 10 11 and 1 × 10 12 ions/cm 2 have been used for the irradiation purpose. Transport properties in the pristine and irradiated PPy nanoparticles have been investigated with permittivity and modulus formalisms to study the polarization effects and conductivity relaxation. With increasing ion fluence, the relaxation peak in imaginary modulus (M ″ ) plots shifts toward high frequency suggesting long range motion of the charge carriers. The AC conductivity studies suggest correlated barrier hopping as the dominant transport mechanism. The hopping distance (R ω ) of the charge carriers decreases with increasing the ion fluence. Binding energy (W m ) calculations depict that polarons are the dominant charge carriers

  14. Effect of hypothyroidism on the nitrergic relaxant responses of corpus cavernosal smooth muscle in rabbits.

    Science.gov (United States)

    Sarac, Bulent; Yildirim, Mustafa K; Bagcivan, Ihsan; Kaya, Kemal; Kilicarslan, Hakan; Yildirim, Sahin

    2006-01-01

    The incidence of hormonal dysfunction as a cause of impotence remains controversial. However, several recent studies have reported evidence of hormonal abnormalities in 25-35% of impotent men. Hypothyroidism has been reported to occur in 6% of impotent men. In the present study, we examined nitrergic responses in hypothyroidism in rabbit corpus cavernosum and compared them with controls. Carbachol-induced relaxation responses and electrical field stimulation (EFS)-induced frequency-dependent relaxations decreased significantly in hypothyroid rabbits. Papaverine and sodium nitroprusside (SNP)-induced relaxation responses did not change significantly in hypothyroid rabbits. The contraction responses of phenylephrine and EFS-induced frequency-dependent contractions were significantly decreased in the hypothyroid group. We can speculate that the reduction of relaxant responses to EFS and carbachol in hypothyroid rabbits can depend on a decreased release of nitric oxide (NO) from nitrergic nerves and endothelium or a reduction of muscarinic receptor density. Also, decreases in contraction responses may depend on diminished adrenoceptor density.

  15. Frequency of anomalies associated with chest deformity in physically fit male candidates reporting for military recruitment

    International Nuclear Information System (INIS)

    Haleem, A.; Hanif, M.S.; Majeed, F.A.; Deen, N.U.; Rahim, K.

    2015-01-01

    To identify the frequency of anomalies associated with chest deformity in physical fit male candidates reporting for military recruitment. Study Design: Observational. Place and Duration of Study: Department of Thoracic Surgery, CMH Rawalpindi from 1st Jan 2008 to 31 Dec 2011. Patients and Methods: Normal healthy physically fit young adolescents being recruited for army were scrolled and those exhibiting chest deformity were isolated and subjected to evaluation. Convenience sampling was carried out. All candidates of chest wall deformity thereafter underwent a thorough physical checkup, pulmonary function tests and echocardiography. Results: A total of 3735 candidates of chest deformity reported at our center for evaluation over this duration. Single deformity patients 3380 (90.5%), mixed deformity patients 355 (9.5%). We found that none of the candidates had any derangement of the lung function tests or electrocardiographic abnormality despite their deformity. However echocardiography detected an abnormality in 161 (4.3%) individuals who were otherwise asymptomatic. Conclusion: Chest deformity should be excluded before physical tests, in all the male candidates reporting for enrolment. If slightest of doubt exists that a candidate has chest deformity then he should be evaluated with echocardiography to exclude cardiac abnormality. Although the associated frequency is only 4.3% but this can subsequently result in a grave event like death. (author)

  16. Status report of the low frequency facility experiment, Virgo R and D

    Energy Technology Data Exchange (ETDEWEB)

    Di Virgilio, A.; Ballardin, G.; Braccini, S.; Bradaschia, C.; Calamai, G.; Casciano, C.; Cavalieri, R.; Cecchi, R.; Cella, G.; Chen, Sheng-Jui; Cuoco, E.; Dattilo, V.; Dominici, P.; Fabbroni, L.; Fazzi, M.; Frasca, S.; Ferrante, I.; Fidecaro, F.; Frasconi, F.; Gennaro, G.; Giazotto, A.; Guidi, G.; Holloway, L.; La Penna, P.; Lomtadze, T.; Losurdo, G.; Majorana, E.; Martelli, F.; Mazzoni, M.; Nenci, F.; Ni, Wei-Tou; Lelli, F.; Paoletti, F.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Perciballi, M.; Poggiani, R.; Porzio, A.; Puppo, P.; Raffaelli, F.; Rapagnani, P.; Ricci, F.; Ricciardi, I.; Solimeno, S.; Stanga, R.; Taddei, R.; Vetrano, F.; Vicere, A.; Zhang, Z

    2003-11-10

    The low frequency facility, a Virgo R and D experiment, is composed by a Fabry-Perot cavity attached and controlled by the Virgo suspension; the goal is to measure the thermal noise of the apparatus above 10 Hz, with a displacement sensitivity as high as 10{sup -18} m/{radical}Hz. Since September 2001 the apparatus, located inside the INFN-Pisa experimental area, has been completely built and put into operation. Vacuum facilities and the control loops have been set up. Transfer functions, necessary to control the cavity, absolute test mass displacement and the first demonstration of the cavity locking are reported.

  17. Ultrasonic relaxations in borate glasses

    International Nuclear Information System (INIS)

    D'Angelo, G.; Tripodo, G.; Carini, G.; Cosio, E.; Bartolotta, A.; Di Marco, G.

    2004-01-01

    The attenuation and velocity of ultrasonic waves of frequencies in the range from 10 to 70 MHz have been measured in M 2 O-B 2 O 3 borate glasses (M: Li or Ag) as a function of temperature between 15 and 350 K. The velocity of sound waves decreases with increasing temperature in all the glasses, the decrease as the temperature is increased is larger in glasses containing silver than in those with lithium. A broad relaxation peak characterises the attenuation behaviour of the lithium and silver borate glasses at temperatures below 100 K and is paralleled by a corresponding dispersive behaviour of the sound velocity. Above 100 K, the ultrasonic velocity shows a nearly linear behaviour regulated by the vibrational anharmonicity, which decreases with increasing content of modifier oxide and is smaller in lithium than in silver borates. These results suggest that the relaxation of structural defects and the anharmonicity of borate glasses are strongly affected by two parameters: the number of bridging bonds per network forming ion and the polarising power of network modifier ions which occupy sites in the existing interstices

  18. Occupational blood exposure among health care workers: I. Frequency and reporting

    DEFF Research Database (Denmark)

    Nelsing, S; Nielsen, T L; Nielsen, Jens Ole

    1993-01-01

    The frequency and reporting rate concerning occupational blood exposure were investigated among former and currently employed medical staff at a Department of Infectious Diseases (DID) having a high prevalence of HIV-positive patients. Subjects were asked to complete an anonymous questionnaire......, carries a real and serious risk of contracting infectious diseases due to occupational exposure to blood. The importance of reporting needs to be emphasized....... describing occupational percutaneous exposure (PCE) and mucocutaneous exposure (MCE) to blood, experienced during their employment at the DID. 135 out of 168 (80%) subjects responded. 45 subjects described 37 incidents of PCE and 15 of MCE. 44 of the exposures (85%) involved HIV-positive blood and 6 (11...

  19. Relaxed Binaural LCMV Beamforming

    NARCIS (Netherlands)

    Koutrouvelis, A.; Hendriks, R.C.; Heusdens, R.; Jensen, Jesper Rindom

    2017-01-01

    In this paper, we propose a new binaural beamforming technique, which can be seen as a relaxation of the linearly constrained minimum variance (LCMV) framework. The proposed method can achieve simultaneous noise reduction and exact binaural cue preservation of the target source, similar to the

  20. Low frequency electromagnetic fields in Switzerland and in Germany. Comprehensive report on various studies

    International Nuclear Information System (INIS)

    Stratmann, M.; Wernli, C.; Grigat, J. P.; Eisenbrandt, H.

    1998-01-01

    The work of two research groups has been combined in this report. Both groups have concerned themselves with the occurrence and the distribution of low-frequency magnetic fields in the human environment. The initiative for the joint documentation came from the Radiation Metrology Section of the Paul Scherrer Institute. This team has investigated the general exposure on the Swiss population due to 50 Hz magnetic fields and the exposure arising from 162/3 Hz magnetic fields in the passenger area of trains. In addition, source-related measurements and frequency analyses up to 200 kHz have been undertaken. As a second group, the 'Research Association: Electromagnetic tolerance of biological systems' of the Technical University of Braunschweig, under the direction of Prof. Karl Brinkmann, has participated in the preparation of this documentation. During the past years, the research association has prepared two extensive studies on the local and temporal distribution of magnetic field sources in human residential areas and has contributed its findings on the residential situation as a supplement to the treatment of the problems described here. Intentionally, the report has not been prepared as a scientific presentation, but rather as informative reading for specialists as well as for the general public. (author)

  1. Idiosyncratic reality claims, relaxation dispositions, and ABC relaxation theory: happiness, literal christianity, miraculous powers, metaphysics, and the paranormal.

    Science.gov (United States)

    Smith, Jonathan C; Karmin, Aaron D

    2002-12-01

    This study examined idiosyncratic reality claims, that is, irrational or paranormal beliefs often claimed to enhance relaxation and happiness and reduce stress. The Smith Idiosyncratic Reality Claims Inventory and the Smith Relaxation Dispositions Inventory (which measures relaxation and stress dispositions, or enduring states of mind frequently associated with relaxation or stress) were given to 310 junior college student volunteers. Principal components factor analysis with varimax rotation identified five idiosyncratic reality claim factors: belief in Literal Christianity; Magic; Space Aliens: After Death experiences; and Miraculous Powers of Meditation, Prayer, and Belief. No factor correlated with increased relaxation dispositions Peace, Energy, or Joy, or reduced dispositional somatic stress, worry, or negative emotion on the Smith Relaxation Dispositions Inventory. It was concluded that idiosyncratic reality claims may not be associated with reported relaxation, happiness, or stress. In contrast, previous research strongly supported self-affirming beliefs with few paranormal assumptions display such an association.

  2. Stress relaxation in viscous soft spheres.

    Science.gov (United States)

    Boschan, Julia; Vasudevan, Siddarth A; Boukany, Pouyan E; Somfai, Ellák; Tighe, Brian P

    2017-10-04

    We report the results of molecular dynamics simulations of stress relaxation tests in athermal viscous soft sphere packings close to their unjamming transition. By systematically and simultaneously varying both the amplitude of the applied strain step and the pressure of the initial condition, we access both linear and nonlinear response regimes and control the distance to jamming. Stress relaxation in viscoelastic solids is characterized by a relaxation time τ* that separates short time scales, where viscous loss is substantial, from long time scales, where elastic storage dominates and the response is essentially quasistatic. We identify two distinct plateaus in the strain dependence of the relaxation time, one each in the linear and nonlinear regimes. The height of both plateaus scales as an inverse power law with the distance to jamming. By probing the time evolution of particle velocities during relaxation, we further identify a correlation between mechanical relaxation in the bulk and the degree of non-affinity in the particle velocities on the micro scale.

  3. Vogel-Fulcher dependence of relaxation rates in a nematic monomer and elastomer

    Science.gov (United States)

    Shenoy, D.; Filippov, S.; Aliev, F.; Keller, P.; Thomsen, D.; Ratna, B.

    2000-12-01

    Dielectric relaxation spectroscopy is used to study the relaxation processes in a nematic monomer and the corresponding cross-linked polymer nematic liquid crystal (elastomer). In the frequency window 10 mHz to 2 GHz the monomer liquid crystal shows a single relaxation whereas the polymer exhibits three relaxation processes, two of which are quantitatively analyzed. The temperature dependence of relaxation times in both the monomer and polymer follows a Vogel-Fulcher behavior. The relaxation processes are identified with specific molecular motions and activation energies are calculated in a linear approximation for comparison with literature data.

  4. Communication: Relaxation-limited electronic currents in extended reservoir simulations

    Science.gov (United States)

    Gruss, Daniel; Smolyanitsky, Alex; Zwolak, Michael

    2017-10-01

    Open-system approaches are gaining traction in the simulation of charge transport in nanoscale and molecular electronic devices. In particular, "extended reservoir" simulations, where explicit reservoir degrees of freedom are present, allow for the computation of both real-time and steady-state properties but require relaxation of the extended reservoirs. The strength of this relaxation, γ, influences the conductance, giving rise to a "turnover" behavior analogous to Kramers turnover in chemical reaction rates. We derive explicit, general expressions for the weak and strong relaxation limits. For weak relaxation, the conductance increases linearly with γ and every electronic state of the total explicit system contributes to the electronic current according to its "reduced" weight in the two extended reservoir regions. Essentially, this represents two conductors in series—one at each interface with the implicit reservoirs that provide the relaxation. For strong relaxation, a "dual" expression-one with the same functional form-results, except now proportional to 1/γ and dependent on the system of interest's electronic states, reflecting that the strong relaxation is localizing electrons in the extended reservoirs. Higher order behavior (e.g., γ2 or 1/γ2) can occur when there is a gap in the frequency spectrum. Moreover, inhomogeneity in the frequency spacing can give rise to a pseudo-plateau regime. These findings yield a physically motivated approach to diagnosing numerical simulations and understanding the influence of relaxation, and we examine their occurrence in both simple models and a realistic, fluctuating graphene nanoribbon.

  5. Hair Dye and Hair Relaxers

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women Hair Dye and Hair Relaxers Share Tweet Linkedin Pin it More sharing ... products. If you have a bad reaction to hair dyes and relaxers, you should: Stop using the ...

  6. Experiments in paramagnetic relaxation

    International Nuclear Information System (INIS)

    Lijphart, E.E.

    1976-01-01

    This thesis presents two attempts to improve the resolving power of the relaxation measurement technique. The first attempt reconsiders the old technique of steady state saturation. When used in conjunction with the pulse technique, it offers the possibility of obtaining additional information about the system in which all-time derivatives are zero; in addition, non-linear effects may be distinguished from each other. The second attempt involved a systematic study of only one system: Cu in the Tutton salts (K and Rb). The systematic approach, the high accuracy of the measurement and the sheer amount of experimental data for varying temperature, magnetic field and concentration made it possible in this case to separate the prevailing relaxation mechanisms reliably

  7. Nonelite exercise-related injuries: participant reported frequency, management and perceptions of their consequences.

    Science.gov (United States)

    Grice, A; Kingsbury, S R; Conaghan, P G

    2014-04-01

    This mixed methods study explored the frequency of sport/exercise-related injuries in nonelite sport, participant-reported management and perceptions of potential injury consequences. Focus group participants, who trained two to four times a week and had previously sustained musculoskeletal sports-related injuries, reported seeking medical advice secondary to advice from teammates or online research. General practitioners were viewed as gatekeepers to specialist secondary care and less able to effectively treat sport-related injuries. Participants displayed limited awareness of potential future implications of injury, and considered physical and psychological benefits of exercise more valuable than potential injury-associated risks. In the survey of physically active people, over half reported sustaining an exercise-related injury (562/1002, 56%). Previously injured respondents were less likely to consider consulting a health professional for injury-related advice than those with no injury history (45% vs 64%; P sports-related injuries and a lack of awareness about appropriate injury management and potential consequences of injury, particularly in the long-term. © 2013 The Authors. Scandinavian Journal of Medicine & Science in Sports published by John Wiley & Sons Ltd.

  8. Relaxation from particle production

    Energy Technology Data Exchange (ETDEWEB)

    Hook, Anson; Marques-Tavares, Gustavo [Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA 94305 (United States)

    2016-12-20

    We consider using particle production as a friction force by which to implement a “Relaxion” solution to the electroweak hierarchy problem. Using this approach, we are able to avoid superplanckian field excursions and avoid any conflict with the strong CP problem. The relaxation mechanism can work before, during or after inflation allowing for inflationary dynamics to play an important role or to be completely decoupled.

  9. Magnetic relaxation in anisotropic magnets

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1971-01-01

    The line shape and the kinematic and thermodynamic slowing down of the critical and paramagnetic relaxation in axially anisotropic materials are discussed. Kinematic slowing down occurs only in the longitudinal relaxation function. The thermodynamic slowing down occurs in either the transverse...... or longitudinal relaxation function depending on the sign of the axial anisotropy....

  10. Momentum constraint relaxation

    International Nuclear Information System (INIS)

    Marronetti, Pedro

    2006-01-01

    Full relativistic simulations in three dimensions invariably develop runaway modes that grow exponentially and are accompanied by violations of the Hamiltonian and momentum constraints. Recently, we introduced a numerical method (Hamiltonian relaxation) that greatly reduces the Hamiltonian constraint violation and helps improve the quality of the numerical model. We present here a method that controls the violation of the momentum constraint. The method is based on the addition of a longitudinal component to the traceless extrinsic curvature A ij -tilde, generated by a vector potential w i , as outlined by York. The components of w i are relaxed to solve approximately the momentum constraint equations, slowly pushing the evolution towards the space of solutions of the constraint equations. We test this method with simulations of binary neutron stars in circular orbits and show that it effectively controls the growth of the aforementioned violations. We also show that a full numerical enforcement of the constraints, as opposed to the gentle correction of the momentum relaxation scheme, results in the development of instabilities that stop the runs shortly

  11. Ultrasonic Relaxation Study of 1-Alkyl-3-methylimidazolium-Based Room-Temperature Ionic Liquids: Probing the Role of Alkyl Chain Length in the Cation.

    Science.gov (United States)

    Zorębski, Michał; Zorębski, Edward; Dzida, Marzena; Skowronek, Justyna; Jężak, Sylwia; Goodrich, Peter; Jacquemin, Johan

    2016-04-14

    Ultrasound absorption spectra of four 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides were determined as a function of the alkyl chain length on the cation from 1-propyl to 1-hexyl from 293.15 to 323.15 K at ambient pressure. Herein, the ultrasound absorption measurements were carried out using a standard pulse technique within a frequency range from 10 to 300 MHz. Additionally, the speed of sound, density, and viscosity have been measured. The presence of strong dissipative processes during the ultrasound wave propagation was found experimentally, i.e., relaxation processes in the megahertz range were observed for all compounds over the whole temperature range. The relaxation spectra (both relaxation amplitude and relaxation frequency) were shown to be dependent on the alkyl side chain length of the 1-alkyl-3-methylimidazolium ring. In most cases, a single-Debye model described the absorption spectra very well. However, a comparison of the determined spectra with the spectra of a few other imidazolium-based ionic liquids reported in the literature (in part recalculated in this work) shows that the complexity of the spectra increases rapidly with the elongation of the alkyl chain length on the cation. This complexity indicates that both the volume viscosity and the shear viscosity are involved in relaxation processes even in relatively low frequency ranges. As a consequence, the sound velocity dispersion is present at relatively low megahertz frequencies.

  12. Relaxation training after stroke: potential to reduce anxiety.

    Science.gov (United States)

    Kneebone, Ian; Walker-Samuel, Natalie; Swanston, Jennifer; Otto, Elisabeth

    2014-01-01

    To consider the feasibility of setting up a relaxation group to treat symptoms of post stroke anxiety in an in-patient post-acute setting; and to explore the effectiveness of relaxation training in reducing self-reported tension. A relaxation group protocol was developed in consultation with a multidisciplinary team and a user group. Over a period of 24 months, 55 stroke patients attended group autogenic relaxation training on a rehabilitation ward. Attendance ranged between one and eleven sessions. Self-reported tension was assessed pre and post relaxation training using the Tension Rating Circles (TRCs). The TRCs identified a significant reduction in self-reported tension from pre to post training, irrespective of the number of sessions attended; z = -3.656, p training. The TRCs proved acceptable to group members, but should be validated against standard anxiety measures. Further exploration of the application of relaxation techniques in clinical practice is desirable. Implications for Rehabilitation Anxiety is prevalent after stroke and likely affects rehabilitation outcomes. Relaxation training is a well proven treatment for anxiety in the non-stroke population. A significant within session reduction in tension, a hallmark symptom of anxiety, was evidenced via group relaxation training delivered in a post-acute, in-patient stroke unit setting. Relaxation training a shows promise as a treatment for anxiety after stroke.

  13. Effect of lithium on endothelium-dependent and neurogenic relaxation of rat corpus cavernosum: role of nitric oxide pathway.

    Science.gov (United States)

    Sadeghipour, Hamed; Ghasemi, Mehdi; Ebrahimi, Farzad; Dehpour, Ahmad Reza

    2007-02-01

    Some studies have reported erectile dysfunction in patients receiving lithium through a mechanism that has not yet been defined. The aim of the present study was to verify the effect of acute lithium administration on the nonadrenergic noncholinergic (NANC)- and endothelium-mediated relaxation of rat isolated corpus cavernosum. The isolated rat corporeal strips were precontracted with phenylephrine hydrochloride (7.5 microM) and electrical field stimulation (EFS) was applied at different frequencies (2, 5, 10, and 15 Hz) to obtain NANC-mediated relaxation or relaxed by adding cumulative doses of acetylcholine (10nM-1mM) to obtain endothelium-dependent relaxation in the presence or absence of lithium (0.3, 0.5, 1, and 5mM). Also, effects of combining lithium (0.3mM) with 30 nM and 0.1 nM L-NAME (an NO synthase inhibitor) on NANC- and acetylcholine-mediated relaxation was investigated, respectively. Moreover, effects of combining lithium (1mM) with 0.1mM and 10 microM L-arginine (a precursor of NO) on NANC- and endothelium-mediated relaxation was assessed, respectively. Also, the effect of lithium (1mM) on relaxation to sodium nitroprusside (SNP; 1nM-1mM), an NO donor, was investigated. The NANC-mediated relaxation was significantly (Pacetylcholine in a concentration-dependent manner. Combination of lithium (0.3mM) with 30 and 0.1 nM L-NAME, which separately had a minimum effect on NANC- and endothelium-mediated relaxation, significantly (Pacetylcholine and EFS, it improved the inhibition by lithium (1mM) of relaxant responses to acetylcholine and EFS, respectively. Also, SNP produced similar concentration-dependent relaxations from both groups. Our experiments indicated that lithium likely by interfering with NO pathway in both endothelium and nitrergic nerve can result in impairment of both the endothelium- and NANC-mediated relaxation of rat corpus cavernosum.

  14. Nuclear magnetic relaxation induced by exchange-mediated orientational randomization: longitudinal relaxation dispersion for spin I = 1.

    Science.gov (United States)

    Nilsson, Tomas; Halle, Bertil

    2012-08-07

    The frequency dependence of the longitudinal relaxation rate, known as the magnetic relaxation dispersion (MRD), can provide a frequency-resolved characterization of molecular motions in complex biological and colloidal systems on time scales ranging from 1 ns to 100 μs. The conformational dynamics of immobilized proteins and other biopolymers can thus be probed in vitro or in vivo by exploiting internal water molecules or labile hydrogens that exchange with a dominant bulk water pool. Numerous water (1)H and (2)H MRD studies of such systems have been reported, but the widely different theoretical models currently used to analyze the MRD data have resulted in divergent views of the underlying molecular motions. We have argued that the essential mechanism responsible for the main dispersion is the exchange-mediated orientational randomization (EMOR) of anisotropic nuclear (electric quadrupole or magnetic dipole) couplings when internal water molecules or labile hydrogens escape from orientationally confining macromolecular sites. In the EMOR model, the exchange process is thus not just a means of mixing spin populations but it is also the direct cause of spin relaxation. Although the EMOR theory has been used in several studies to analyze water (2)H MRD data from immobilized biopolymers, the fully developed theory has not been described. Here, we present a comprehensive account of a generalized version of the EMOR theory for spin I = 1 nuclides like (2)H. As compared to a previously described version of the EMOR theory, the present version incorporates three generalizations that are all essential in applications to experimental data: (i) a biaxial (residual) electric field gradient tensor, (ii) direct and indirect effects of internal motions, and (iii) multiple sites with different exchange rates. In addition, we describe and assess different approximations to the exact EMOR theory that are useful in various regimes. In particular, we consider the experimentally

  15. Relaxation time in confined disordered systems

    International Nuclear Information System (INIS)

    Chamati, H.; Korutcheva, E.

    2006-05-01

    The dynamic critical behavior of a quenched hypercubic sample of linear size L is considered within the 'random T c ' field theoretical model with purely relaxation dynamic (Model A). The dynamic finite size scaling behavior is established and analyzed when the system is quenched from a homogeneous phase towards its critical temperature. The obtained results are compared to those reported in the literature. (author)

  16. A model for the generic alpha relaxation in viscous liquids

    DEFF Research Database (Denmark)

    Dyre, Jeppe

    2005-01-01

    Dielectric measurements on molecular liquids just above the glass transition indicate that alpha relaxation is characterized by a generic high-frequency loss varying as one over square root of frequency, whereas deviations from this come from one or more low-lying beta processes [Olsen et al., Phys...

  17. Beta relaxation of nonpolymeric liquids close to the glass transition

    DEFF Research Database (Denmark)

    Olsen, Niels Boye; Christensen, Tage Emil; Dyre, Jeppe

    2000-01-01

    Dielectric beta relaxation in a pyridine-toluene solution is studied close to the glass transition. Loss peak frequency and maximum loss both exhibit thermal hysteresis. An annealing-state-independent parameter involving loss and loss peak frequency is identified. This parameter has a simple...

  18. Relaxation dynamics of multilayer triangular Husimi cacti

    Science.gov (United States)

    Galiceanu, Mircea; Jurjiu, Aurel

    2016-09-01

    We focus on the relaxation dynamics of multilayer polymer structures having, as underlying topology, the Husimi cactus. The relaxation dynamics of the multilayer structures is investigated in the framework of generalized Gaussian structures model using both Rouse and Zimm approaches. In the Rouse type-approach, we determine analytically the complete eigenvalues spectrum and based on it we calculate the mechanical relaxation moduli (storage and loss modulus) and the average monomer displacement. First, we monitor these physical quantities for structures with a fixed generation number and we increase the number of layers, such that the linear topology will smoothly come into play. Second, we keep constant the size of the structures, varying simultaneously two parameters: the generation number of the main layer, G, and the number of layers, c. This fact allows us to study in detail the crossover from a pure Husimi cactus behavior to a predominately linear chain behavior. The most interesting situation is found when the two limiting topologies cancel each other. For this case, we encounter in the intermediate frequency/time domain regions of constant slope for different values of the parameter set (G, c) and we show that the number of layers follows an exponential-law of G. In the Zimm-type approach, which includes the hydrodynamic interactions, the quantities that describe the mechanical relaxation dynamics do not show scaling behavior as in the Rouse model, except the limiting case, namely, a very high number of layers and low generation number.

  19. Improving the Performance of Poor Readers through Autogenic Relaxation Training.

    Science.gov (United States)

    Frey, Herbert

    1980-01-01

    Reports that the addition of 15 minutes of relaxation training to weekly remedial reading periods for disabled readers throughout a school year raised concentration levels and decreased anxiety, neuroticism, and number of reading errors. Describes a few types of relaxation exercises that may be helpful. (ET)

  20. Relaxation peak near 200 K in NiTi alloy

    Science.gov (United States)

    Zhu, J. S.; Schaller, R.; Benoit, W.

    1989-10-01

    Internal friction (IF), frequency ( f), electrical resistance ( R) and zero point movement of the torsion pendulum (ɛ) have been measured in near equi-atomic NiTi alloy in order to clarify the mechanism for the relaxation peak near 200 K. The height of the relaxation peak decreases successively with thermal cycling and settles down to a lower stable value in running 15 cycles. However, the electrical resistance of the sample shows a variation in contrast with the internal friction. Both of them will return to the initial state after a single annealing at 773 K for 1 h. The probable mechanism of this relaxation peak was discussed.

  1. Variational formulation of relaxed and multi-region relaxed magnetohydrodynamics

    Science.gov (United States)

    Dewar, R. L.; Yoshida, Z.; Bhattacharjee, A.; Hudson, S. R.

    2015-12-01

    > Ideal magnetohydrodynamics (IMHD) is strongly constrained by an infinite number of microscopic constraints expressing mass, entropy and magnetic flux conservation in each infinitesimal fluid element, the latter preventing magnetic reconnection. By contrast, in the Taylor relaxation model for formation of macroscopically self-organized plasma equilibrium states, all these constraints are relaxed save for the global magnetic fluxes and helicity. A Lagrangian variational principle is presented that leads to a new, fully dynamical, relaxed magnetohydrodynamics (RxMHD), such that all static solutions are Taylor states but also allows state with flow. By postulating that some long-lived macroscopic current sheets can act as barriers to relaxation, separating the plasma into multiple relaxation regions, a further generalization, multi-region relaxed magnetohydrodynamics (MRxMHD) is developed.

  2. Dynamics of relaxed inflation

    Science.gov (United States)

    Tangarife, Walter; Tobioka, Kohsaku; Ubaldi, Lorenzo; Volansky, Tomer

    2018-02-01

    The cosmological relaxation of the electroweak scale has been proposed as a mechanism to address the hierarchy problem of the Standard Model. A field, the relaxion, rolls down its potential and, in doing so, scans the squared mass parameter of the Higgs, relaxing it to a parametrically small value. In this work, we promote the relaxion to an inflaton. We couple it to Abelian gauge bosons, thereby introducing the necessary dissipation mechanism which slows down the field in the last stages. We describe a novel reheating mechanism, which relies on the gauge-boson production leading to strong electro-magnetic fields, and proceeds via the vacuum production of electron-positron pairs through the Schwinger effect. We refer to this mechanism as Schwinger reheating. We discuss the cosmological dynamics of the model and the phenomenological constraints from CMB and other experiments. We find that a cutoff close to the Planck scale may be achieved. In its minimal form, the model does not generate sufficient curvature perturbations and additional ingredients, such as a curvaton field, are needed.

  3. Associations Between the Self-Reported Frequency of Hearing Chemical Alarms in Theater and Visuospatial Function in Gulf War Veterans.

    Science.gov (United States)

    Chao, Linda L

    2016-10-01

    The aim of this study was to examine the relationship between the self-reported frequencies of hearing chemical alarms during deployment and visuospatial function in Gulf War (GW) veterans. The relationship between the self-reported frequency of hearing chemical alarms, neurobehavioral, and volumetric brain imaging data was examined with correlational, regression, and mediation analyses. The self-reported frequency of hearing chemical alarms was inversely associated with and significantly predicted performance on a visuospatial task (ie, Block Design) over and above potentially confounding variables, including concurrent, correlated GW-related exposures. This effect was partially mediated by the relationship between hearing chemical alarms and lateral occipital cortex volume. Exposure to substances that triggered chemical alarms during GW deployment likely had adverse effects on veterans' brain structure and function, warranting further investigation of whether these GW veterans are at an increased risk for dementia.

  4. Dielectric relaxation of selenium-tellurium mixed former glasses

    Science.gov (United States)

    Palui, A.; Ghosh, A.

    2017-05-01

    We report the study of dielectric properties of mixed network former glasses of composition 0.3Ag2O-0.7(xSeO2-(1-x)TeO2); x=0, 0.1, 0.3, 0.4, 0.5 and 0.6 in a wide frequency 10 Hz - 2 MHz and temperature range 223 K - 403 K. The experimental data have been analyzed in the framework of complex dielectric permittivity. The dielectric permittivity data have been analyzed using the Cole-Cole function. The inverse temperature dependence of relaxation time obtained from real part of dielectric permittivity data follows the Arrhenius relation. The activation energy shows mixed glass former effect with variation of mixed former ratio. A non-zero value of shape parameters is observed and it is almost independent of temperature and composition.

  5. Limiting conditions for operation relaxation program

    International Nuclear Information System (INIS)

    Merz, J.F.

    1985-01-01

    The purpose of this effort was to assess the impact of system maintenance unavailability on plant risk to provide technical justification for the relaxation of system limiting conditions for operation from three to seven days. The primary goal of the relaxation program is to allow for more thorough equipment maintenance. A potential increase in out-of-service time for a particular outage caused by the performance of more effective repairs will be counterbalanced by a probable decrease in the frequency in the outage rate of a component. Benefits resulting from an increase in allowed outage time include: (a) a potential reduction in total system out-of-service time, (b) a minimization of challenges to plant systems, and (c) a reduction in the number of emergency technical specification change requests. This program therefore offers an opportunity to more effectively manage plant maintenance and operation

  6. Ferromagnetism versus slow paramagnetic relaxation in Fe-doped Li3N

    Science.gov (United States)

    Fix, M.; Jesche, A.; Jantz, S. G.; Bräuninger, S. A.; Klauss, H.-H.; Manna, R. S.; Pietsch, I. M.; Höppe, H. A.; Canfield, P. C.

    2018-02-01

    We report on isothermal magnetization, Mössbauer spectroscopy, and magnetostriction as well as temperature-dependent alternating-current (ac) susceptibility, specific heat, and thermal expansion of single crystalline and polycrystalline Li2(Li1 -xFex) N with x =0 and x ≈0.30 . Magnetic hysteresis emerges at temperatures below T ≈50 K with coercivity fields of up to μ0H =11.6 T at T =2 K and magnetic anisotropy energies of 310 K (27 meV). The ac susceptibility is strongly frequency-dependent (f =10 -10 000 Hz) and reveals an effective energy barrier for spin reversal of Δ E ≈1100 K (90 meV). The relaxation times follow Arrhenius behavior for T >25 K . For T <10 K , however, the relaxation times of τ ≈1010 s are only weakly temperature-dependent, indicating the relevance of a quantum tunneling process instead of thermal excitations. The magnetic entropy amounts to more than 25 J molFe-1 K-1, which significantly exceeds R ln 2 , the value expected for the entropy of a ground-state doublet. Thermal expansion and magnetostriction indicate a weak magnetoelastic coupling in accordance with slow relaxation of the magnetization. The classification of Li2(Li1 -xFex) N as ferromagnet is stressed and contrasted with highly anisotropic and slowly relaxing paramagnetic behavior.

  7. Study of the relaxation of electron velocity distributions in gases

    Energy Technology Data Exchange (ETDEWEB)

    Braglia, G L [Parma Univ. (Italy). Ist. di Fisica; Caraffini, G L; Diligenti, M [Parma Univ. (Italy). Ist. di Matematica

    1981-03-11

    The Fokker-Planck equation governing the relaxation of the electron speed (energy) distribution in gases is solved in a number of cases of special interest. The solution is given in terms of eigenfunctions of the Fokker-Planck operator, satisfying an orthonormalization condition in which the steady-state distribution is the weight function. The real cross-sections of the noble gases He, Ne, Ar, Kr and Xe, together with model collision frequencies of the form ..nu..(v) = ..cap alpha..vsup(n) with n = 0.5, 1, 1.5, 3 and 3.5, are used to calculate eigenvalues and eigenfunctions. The first fifteen eigenvalues are obtained in each case both in the absence and in the presence of a d.c. electric field and, in the latter case, both with atoms at rest and atoms in motion. Calculations of relaxation times and examples of evolutions towards their steady-state forms of given initial distributions are reported in several particular cases.

  8. Complex dielectric modulus and relaxation response at low microwave frequency region of dielectric ceramic Ba6-3xNd8+2xTi18O54

    Directory of Open Access Journals (Sweden)

    Chian Heng Lee

    2014-10-01

    Full Text Available The desirable characteristics of Ba6-3xNd8+2xTi18O54 include high dielectric constant, low loss tangent, and high quality factor developed a new field for electronic applications. The microwave dielectric properties of Ba6-3xNd8+2xTi18O54, with x = 0.15 ceramics at different sintering temperatures (600–1300°C were investigated. The phenomenon of polarization produced by the applied electric field was studied. The dielectric properties with respect to frequency from 1 MHz to 1.5 GHz were measured using Impedance Analyzer, and the results were compared and analyzed. The highest dielectric permittivity and lowest loss factor were defined among the samples. The complex dielectric modulus was evaluated from the measured parameters of dielectric measurement in the same frequency range, and used to differentiate the contribution of grain and grain boundary.

  9. Frequency Domain Computer Programs for Prediction and Analysis of Rail Vehicle Dynamics : Volume 1. Technical Report

    Science.gov (United States)

    1975-12-01

    Frequency domain computer programs developed or acquired by TSC for the analysis of rail vehicle dynamics are described in two volumes. Volume I defines the general analytical capabilities required for computer programs applicable to single rail vehi...

  10. High frequency microphone measurements for transition detection on airfoils. Risø C2-18 appendix report

    DEFF Research Database (Denmark)

    Døssing, Mads

    Time series of pressure fluctuations has been obtained using high frequency microphones distributed over the surface of airfoils undergoing wind tunnel tests in the LM Windtunnel, owned by ’LM Glasfiber’, Denmark. The present report describes the dataanalysis, with special attention given to tran...

  11. High frequency microphone measurements for transition detection on airfoils. Risø B1-18 appendix report

    DEFF Research Database (Denmark)

    Døssing, Mads

    Time series of pressure fluctuations has been obtained using high frequency microphones distributed over the surface of airfoils undergoing wind tunnel tests in the LM Windtunnel, owned by ’LM Glasfiber’, Denmark. The present report describes the dataanalysis, with special attention given to tran...

  12. Evaluation of relaxation time measurements by magnetic resonance imaging. A phantom study

    DEFF Research Database (Denmark)

    Kjaer, L; Thomsen, C; Henriksen, O

    1987-01-01

    Several circumstances may explain the great variation in reported proton T1 and T2 relaxation times usually seen. This study was designed to evaluate the accuracy of relaxation time measurements by magnetic resonance imaging (MRI) operating at 1.5 tesla. Using a phantom of nine boxes with different...... concentrations of CuSO4 and correlating the calculated T1 and T2 values with reference values obtained by two spectrometers (corrected to MRI-proton frequency = 64 MHz) we found a maximum deviation of about 10 per cent. Measurements performed on a large water phantom in order to evaluate the homogeneity...... in the imaging plane showed a variation of less than 10 per cent within 10 cm from the centre of the magnet in all three imaging planes. Changing the gradient field strength apparently had no influence on the T2 values recorded. Consequently diffusion processes seem without significance. It is concluded...

  13. High frequency conductivity in carbon nanotubes

    Directory of Open Access Journals (Sweden)

    S. S. Abukari

    2012-12-01

    Full Text Available We report on theoretical analysis of high frequency conductivity in carbon nanotubes. Using the kinetic equation with constant relaxation time, an analytical expression for the complex conductivity is obtained. The real part of the complex conductivity is initially negative at zero frequency and become more negative with increasing frequency, until it reaches a resonance minimum at ω ∼ ωB for metallic zigzag CNs and ω < ωB for armchair CNs. This resonance enhancement is indicative for terahertz gain without the formation of current instabilities induced by negative dc conductivity. We noted that due to the high density of states of conduction electrons in metallic zigzag carbon nanotubes and the specific dispersion law inherent in hexagonal crystalline structure result in a uniquely high frequency conductivity than the corresponding values for metallic armchair carbon nanotubes. We suggest that this phenomenon can be used to suppress current instabilities that are normally associated with a negative dc differential conductivity.

  14. Calorimetric and relaxation properties of xylitol-water mixtures

    Science.gov (United States)

    Elamin, Khalid; Sjöström, Johan; Jansson, Helén; Swenson, Jan

    2012-03-01

    We present the first broadband dielectric spectroscopy (BDS) and differential scanning calorimetry study of supercooled xylitol-water mixtures in the whole concentration range and in wide frequency (10-2-106 Hz) and temperature (120-365 K) ranges. The calorimetric glass transition, Tg, decreases from 247 K for pure xylitol to about 181 K at a water concentration of approximately 37 wt. %. At water concentrations in the range 29-35 wt. % a plentiful calorimetric behaviour is observed. In addition to the glass transition, almost simultaneous crystallization and melting events occurring around 230-240 K. At higher water concentrations ice is formed during cooling and the glass transition temperature increases to a steady value of about 200 K for all higher water concentrations. This Tg corresponds to an unfrozen xylitol-water solution containing 20 wt. % water. In addition to the true glass transition we also observed a glass transition-like feature at 220 K for all the ice containing samples. However, this feature is more likely due to ice dissolution [A. Inaba and O. Andersson, Thermochim. Acta, 461, 44 (2007)]. In the case of the BDS measurements the presence of water clearly has an effect on both the cooperative α-relaxation and the secondary β-relaxation. The α-relaxation shows a non-Arrhenius temperature dependence and becomes faster with increasing concentration of water. The fragility of the solutions, determined by the temperature dependence of the α-relaxation close to the dynamic glass transition, decreases with increasing water content up to about 26 wt. % water, where ice starts to form. This decrease in fragility with increasing water content is most likely caused by the increasing density of hydrogen bonds, forming a network-like structure in the deeply supercooled regime. The intensity of the secondary β-relaxation of xylitol decreases noticeably already at a water content of 2 wt. %, and at a water content above 5 wt. % it has been replaced by a

  15. Under-reporting of alcohol consumption in household surveys: a comparison of quantity-frequency, graduated-frequency and recent recall.

    Science.gov (United States)

    Stockwell, Tim; Donath, Susan; Cooper-Stanbury, Mark; Chikritzhs, Tanya; Catalano, Paul; Mateo, Cid

    2004-08-01

    To compare alternative survey methods for estimating (a) levels of at risk alcohol consumption and (b) total volume of alcohol consumed per capita in comparison with estimates from sales data and to investigate reasons for under-reporting. The homes of respondents who were eligible and willing to participate. A total of 21,674 Australians aged 14 years and older. A 2001 national household survey of drug use, experiences and attitudes with weights applied for age, sex, geographic location and day of week of interview. Self-completion questionnaire using quantity-frequency (QF) and graduated-frequency (GF) methods plus two questions about consumption 'yesterday': one in standard drinks, another with empirically based estimates of drink size and strength. The highest estimate of age 14 + per capita consumption of 7.00 l of alcohol derived from recall of consumption 'yesterday' or 76.8% of the official estimate. The lowest was QF with 49.8%. When amount consumed 'yesterday' was recalled in standard drinks this estimate was 5.27 l. GF questions yielded higher estimates than did QF questions both for total volume (5.25 versus 4.54 l) and also for the proportion of the population at risk of long-term alcohol-related harm (10.6%versus 8.1%). With the detailed 'yesterday' method 61% of all consumption was on high risk drinking days. Questions about typical quantities of alcohol consumed can lead to underestimates, as do questions about drinking 'standard drinks' of alcohol. Recent recall methods encourage fuller reporting of volumes plus more accurate estimates of unrecorded consumption and the proportion of total alcohol consumption that places drinkers at risk of harm. However, they do not capture longer-term drinking patterns. It is recommended that both recent recall and measures of longer-term drinking patterns are included in national surveys.

  16. [Midline Cyst of the Prostate with Increased Urinary Frequency and Urgency : A Case Report].

    Science.gov (United States)

    Nakano, Kosuke; Kiuchi, Hiroshi; Miyagawa, Yasushi; Tsujimura, Akira; Nonomura, Norio

    2018-02-01

    A 40-year-old man presented to our institution with a few-month history of increased urinary frequency, urgency and voiding difficulty. He had severe lower urinary tract symptoms with an International Prostate Symptom Score of 28 and quality of life score of 6. The mean urinary frequency and voided volume was 20 times per day and 150 ml, respectively. Abdominal ultrasonography and pelvic magnetic resonance imaging revealed the prostate measuring 15 cm3 with a 3 cm midline cyst which compressed the posterior of the bladder wall. A subsequent examination indicated that his lower urinary tract symptoms could be attributed to the cystic mass which mainly affected his storage symptoms. The patient underwent transurethral unroofing of the prostate cyst. Immediately after the surgery, his storage symptoms were improved greatly. The voiding volume was increased to 250 ml, and the frequency of urination was decreased to 8 times. No recurrent symptoms were found for seven months after the surgery.

  17. Relaxation dispersion in MRI induced by fictitious magnetic fields.

    Science.gov (United States)

    Liimatainen, Timo; Mangia, Silvia; Ling, Wen; Ellermann, Jutta; Sorce, Dennis J; Garwood, Michael; Michaeli, Shalom

    2011-04-01

    A new method entitled Relaxation Along a Fictitious Field (RAFF) was recently introduced for investigating relaxations in rotating frames of rank ≥ 2. RAFF generates a fictitious field (E) by applying frequency-swept pulses with sine and cosine amplitude and frequency modulation operating in a sub-adiabatic regime. In the present work, MRI contrast is created by varying the orientation of E, i.e. the angle ε between E and the z″ axis of the second rotating frame. When ε > 45°, the amplitude of the fictitious field E generated during RAFF is significantly larger than the RF field amplitude used for transmitting the sine/cosine pulses. Relaxation during RAFF was investigated using an invariant-trajectory approach and the Bloch-McConnell formalism. Dipole-dipole interactions between identical (like) spins and anisochronous exchange (e.g., exchange between spins with different chemical shifts) in the fast exchange regime were considered. Experimental verifications were performed in vivo in human and mouse brain. Theoretical and experimental results demonstrated that changes in ε induced a dispersion of the relaxation rate constants. The fastest relaxation was achieved at ε ≈ 56°, where the averaged contributions from transverse components during the pulse are maximal and the contribution from longitudinal components are minimal. RAFF relaxation dispersion was compared with the relaxation dispersion achieved with off-resonance spin lock T(₁ρ) experiments. As compared with the off-resonance spin lock T(₁ρ) method, a slower rotating frame relaxation rate was observed with RAFF, which under certain experimental conditions is desirable. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. The Use of High-Frequency Percussive Ventilation for Whole-Lung Lavage: A Case Report.

    Science.gov (United States)

    Kinthala, Sudhakar; Liang, Mark; Khusid, Felix; Harrison, Sebron

    2018-04-23

    Whole-lung lavage (WLL) remains the gold standard in the treatment of pulmonary alveolar proteinosis. However, anesthetic management during WLL can be challenging because of the risk of intraoperative hypoxemia and various cardiorespiratory complications of 1-lung ventilation. Here, we describe a novel strategy involving the application of high-frequency percussive ventilation using a volumetric diffusive respirator (VDR-4) during WLL in a 47-year-old woman with pulmonary alveolar proteinosis. Our observations suggest that high-frequency percussive ventilation is a potentially effective ventilation strategy during WLL that may reduce the risk of hypoxemia and facilitate lavage.

  19. ATWS: a reappraisal. Part III. Frequency of anticipated transients. Interim report

    International Nuclear Information System (INIS)

    Leverenz, F.L. Jr.; Koren, J.M.; Erdmann, R.C.; Lellouche, G.S.

    1978-07-01

    The document is Part III of the Institute study of the ATWS question. The frequencies of the various events which have led to a reactor scram are documented from the nuclear power plant records. Some of these events, in the absence of scram, could lead to undesirable system response and are the ''transients of significance'' which comprise the anticipated transients of the ATWS question

  20. Breakdown criteria due to radio-frequency fields in vacuum. Final report

    International Nuclear Information System (INIS)

    Reid, D.W.; Lohsen, R.A.

    1982-01-01

    The factors that affect the voltage at which vacuum gaps break down are analyzed. Based on the literature and some simplifying assumptions, a functional dependence is hypothesized. The hypothesis is related to a proposed experiment using radio-frequency power to generate the breakdown voltage

  1. Brief Report: Developing Spatial Frequency Biases for Face Recognition in Autism and Williams Syndrome

    Science.gov (United States)

    Leonard, Hayley C.; Annaz, Dagmara; Karmiloff-Smith, Annette; Johnson, Mark H.

    2011-01-01

    The current study investigated whether contrasting face recognition abilities in autism and Williams syndrome could be explained by different spatial frequency biases over developmental time. Typically-developing children and groups with Williams syndrome and autism were asked to recognise faces in which low, middle and high spatial frequency…

  2. High frequency electromagnetic impedance measurements for characterization, monitoring and verification efforts. 1998 annual progress report

    International Nuclear Information System (INIS)

    Becker, A.; Lee, K.H.; Pellerin, L.

    1998-01-01

    'Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small due, and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high resolution imaging, accurate measurements are necessary so the field data can be mapped into the space of the subsurface parameters. The authors are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach, known as the magnetotelluric (MT) method at low frequencies. Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques. The summary of the work to date is divided into three sections: equipment procurement, instrumentation, and theoretical developments. For most earth materials, the frequency range from 1 to 100 MHz encompasses a very difficult transition zone between the wave propagation of displacement currents and the diffusive behavior of conduction currents. Test equipment, such as signal generators and amplifiers, does not cover the entire range except at great expense. Hence the authors have divided the range of investigation into three sub-ranges: 1--10 MHz, 10--30 MHz, and 30--100 MHz. Results to date are in the lowest frequency range of 1--10 MHz. Even though conduction currents

  3. Relaxed states with plasma flow

    International Nuclear Information System (INIS)

    Avinash, K.; Taylor, J.B.

    1991-01-01

    In the theory of relaxation, a turbulent plasma reaches a state of minimum energy subject to constant magnetic helicity. In this state the plasma velocity is zero. Attempts have been made by introducing a number of different constraints, to obtain relaxed states with plasma flow. It is shown that these alternative constraints depend on two self-helicities, one for ions, and one for electrons. However, whereas there are strong arguments for the effective invariance of the original magnetic-helicity, these arguments do not apply to the self-helicities. Consequently the existence of relaxed states with flow remains in doubt. (author)

  4. Dielectric relaxation of glass particles with conductive nano-coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Shahid [Applied Technologies Department, QinetiQ Limited, Cody Technology Park, Farnborough, Hampshire, GU14 0LX (United Kingdom)

    2009-03-21

    This research focuses on the dielectric properties of particles consisting of glass cores with nanometre conductive coatings. The effects of the core glass particle shape (sphere, flake and fibre) and size are investigated for different coating characteristics over the frequency range 0.5-18 GHz. Experimental results for the coated glass particle combinations show the existence of a dielectric loss peak. This feature is associated with interfacial relaxation between the insulating core glass particle and the nanoscale conductive coating. The relaxation mechanism provides enhanced loss that is not observed in conventional solid metal particle composites. The results are fitted to a model, which shows that the relaxation frequency increases with increasing coating conductivity and thickness, with additional parameters identified for further particle optimizations.

  5. Low-frequency electromagnetic measurements as a zero-time discriminant of nuclear and chemical explosions - OSI research final report

    International Nuclear Information System (INIS)

    Sweeney, J.J.

    1996-12-01

    This is the final report on a series of investigations of low frequency (1-40 Hz) electromagnetic signals produced by above ground and underground chemical explosions and their use for confidence building under the Comprehensive Test-Ban Treaty. I conclude that low frequency electromagnetic measurements can be a very powerful tool for zero-time discrimination of chemical and nuclear explosions for yields of 1 Kt or greater, provided that sensors can be placed within 1-2 km of the suspected detonation point in a tamper-proof, low noise environment. The report includes descriptions and analyses of low frequency electromagnetic measurements associated with chemical explosions carried out in a variety of settings (shallow borehole, open pit mining, underground mining). I examine cavity pressure data from the Non-Proliferation Experiment (underground chemical explosion) and present the hypothesis that electromagnetic signals produced by underground chemical explosions could be produced during rock fracturing. I also review low frequency electromagnetic data from underground nuclear explosions acquired by Lawrence Livermore National Laboratory during the late 1980s. (author)

  6. Mechanical relaxation in chalcogenide glasses of the Ge-As-S system

    International Nuclear Information System (INIS)

    Bilanych, V.S.; Melnychenko, T.D.; Rizak, V.M.; Makauz, I.I.

    2006-01-01

    The temperature and frequency-related dependences of the internal friction and the shear modulus in Ge x As 40-x S 60 glasses have been studied. The maxima of internal friction of both the relaxation and non relaxation types have been found in the low-temperature range. A relaxation maximum has been revealed in the vitrification region, and its parameters have been determined. Possible mechanisms of these processes have been discussed

  7. Effect of water-methanol mixed solvents on the ultrasonic relaxation of cadmium acetate

    International Nuclear Information System (INIS)

    Sree Rama Murthy, J.; Ramachandra Rao, B.

    1976-01-01

    Measurements of ultrasonic absorption have been made by pulse technique in 1 M solutions of cadmium acetate with water-methanol mixed solvents. Results are analysed by assuming a single relaxation mechanism. The characteristic frequency of relaxation is found to decrease with increasing composition of methanol in the solvent. It is proposed that the mechanism of relaxation may be perturbation of chemical equilibrium between complex CdAc + ions and Cd ++ , Ac - species by soundwaves. (author)

  8. A validity study of self-reported daily texting frequency, cell phone characteristics, and texting styles among young adults.

    Science.gov (United States)

    Gold, Judith E; Rauscher, Kimberly J; Zhu, Motao

    2015-04-02

    Texting is associated with adverse health effects including musculoskeletal disorders, sleep disturbances, and traffic crashes. Many studies have relied on self-reported texting frequency, yet the validity of self-reports is unknown. Our objective was to provide some of the first data on the validity of self-reported texting frequency, cell phone characteristics including input device (e.g. touchscreen), key configuration (e.g., QWERTY), and texting styles including phone orientation (e.g., horizontal) and hands holding the phone while texting. Data were collected using a self-administered questionnaire and observation of a texting task among college students ages 18 to 24. To gauge agreement between self-reported and phone bill-derived categorical number of daily text messages sent, we calculated percent of agreement, Spearman correlation coefficient, and a linear weighted kappa statistic. For agreement between self-reported and observed cell phone characteristics and texting styles we calculated percentages of agreement. We used chi-square tests to detect significant differences (α = 0.05) by gender and study protocol. There were 106 participants; 87 of which had complete data for texting frequency analyses. Among these 87, there was 26% (95% CI: 21-31) agreement between self-reported and phone bill-derived number of daily text messages sent with a Spearman's rho of 0.48 and a weighted kappa of 0.17 (95% CI: 0.06-0.27). Among those who did not accurately report the number of daily texts sent, 81% overestimated this number. Among the full sample (n = 106), there was high agreement between self-reported and observed texting input device (96%, 95% CI: 91-99), key configuration (89%, 95% CI: 81-94), and phone orientation while texting (93%, 95% CI: 86-97). No differences were found by gender or study protocol among any items. While young adults correctly reported their cell phone's characteristics and phone orientation while texting, most incorrectly

  9. Dynamics of the α-relaxation in glass-forming polymers. Study by neutron scattering and relaxation techniques

    Science.gov (United States)

    Colmenero, J.

    1993-12-01

    The dynamics of the α-relaxation in three different polymeric systems, poly(vinyl methyl ether) (PVME), poly(vinyl chloride) (PVC) and poly(bisphenol A, 2-hydroxypropylether) (PH) has been studied by means of relaxation techniques and quasielastic neutron scattering (backscattering spectrometers IN10 and IN13 at the ILL-Grenoble). By using these techniques we have covered a wide time scale ranging from mesoscopic to macroscopic times (10 -10 -10 1 s). For analyzing the experimental data we have developed a phenomenological procedure in the frequency domain based on the Havriliak-Negami relaxation function, which in fact implies a Kohlrausch-Williams-Watts relaxation function in the time domain. The results obtained indicate that the dynamics of the α-relaxation in a wide time scale shows a clear non-Debye behaviour. The shape of the relaxation functions is found to be similar for the different techniques used and independent of temperature and momentum transfer ( Q). Moreover, the characteristic relaxation times deduced from the fitting of the experimental data can also be described using only one Vogel-Fulcher functional form. Besides we found that the Q-dependence of the relaxation times obtained by QENS is given by a power law, τ( Q) ∞ Q- n ( n>2), n being dependent on the system, and that the Q-behaviour and the non-Debye behaviour are directly correlated. In the case of PVC, time of flight (TOF) neutron scattering experiments confirm these results in a shorter time scale (2×10 -11 -2× 10 -12 s). Moreover, TOF results also suggest the possibility of interpreting the “fast process” usually detected in glass-forming systems as a Debye-like short regime of the α-relaxation.

  10. Dependence of Brownian and Néel relaxation times on magnetic field strength

    International Nuclear Information System (INIS)

    Deissler, Robert J.; Wu, Yong; Martens, Michael A.

    2014-01-01

    Purpose: In magnetic particle imaging (MPI) and magnetic particle spectroscopy (MPS) the relaxation time of the magnetization in response to externally applied magnetic fields is determined by the Brownian and Néel relaxation mechanisms. Here the authors investigate the dependence of the relaxation times on the magnetic field strength and the implications for MPI and MPS. Methods: The Fokker–Planck equation with Brownian relaxation and the Fokker–Planck equation with Néel relaxation are solved numerically for a time-varying externally applied magnetic field, including a step-function, a sinusoidally varying, and a linearly ramped magnetic field. For magnetic fields that are applied as a step function, an eigenvalue approach is used to directly calculate both the Brownian and Néel relaxation times for a range of magnetic field strengths. For Néel relaxation, the eigenvalue calculations are compared to Brown's high-barrier approximation formula. Results: The relaxation times due to the Brownian or Néel mechanisms depend on the magnitude of the applied magnetic field. In particular, the Néel relaxation time is sensitive to the magnetic field strength, and varies by many orders of magnitude for nanoparticle properties and magnetic field strengths relevant for MPI and MPS. Therefore, the well-known zero-field relaxation times underestimate the actual relaxation times and, in particular, can underestimate the Néel relaxation time by many orders of magnitude. When only Néel relaxation is present—if the particles are embedded in a solid for instance—the authors found that there can be a strong magnetization response to a sinusoidal driving field, even if the period is much less than the zero-field relaxation time. For a ferrofluid in which both Brownian and Néel relaxation are present, only one relaxation mechanism may dominate depending on the magnetic field strength, the driving frequency (or ramp time), and the phase of the magnetization relative to the

  11. Spiking irregularity and frequency modulate the behavioral report of single-neuron stimulation.

    Science.gov (United States)

    Doron, Guy; von Heimendahl, Moritz; Schlattmann, Peter; Houweling, Arthur R; Brecht, Michael

    2014-02-05

    The action potential activity of single cortical neurons can evoke measurable sensory effects, but it is not known how spiking parameters and neuronal subtypes affect the evoked sensations. Here, we examined the effects of spike train irregularity, spike frequency, and spike number on the detectability of single-neuron stimulation in rat somatosensory cortex. For regular-spiking, putative excitatory neurons, detectability increased with spike train irregularity and decreasing spike frequencies but was not affected by spike number. Stimulation of single, fast-spiking, putative inhibitory neurons led to a larger sensory effect compared to regular-spiking neurons, and the effect size depended only on spike irregularity. An ideal-observer analysis suggests that, under our experimental conditions, rats were using integration windows of a few hundred milliseconds or more. Our data imply that the behaving animal is sensitive to single neurons' spikes and even to their temporal patterning. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. A simple measurement method of molecular relaxation in a gas by reconstructing acoustic velocity dispersion

    Science.gov (United States)

    Zhu, Ming; Liu, Tingting; Zhang, Xiangqun; Li, Caiyun

    2018-01-01

    Recently, a decomposition method of acoustic relaxation absorption spectra was used to capture the entire molecular multimode relaxation process of gas. In this method, the acoustic attenuation and phase velocity were measured jointly based on the relaxation absorption spectra. However, fast and accurate measurements of the acoustic attenuation remain challenging. In this paper, we present a method of capturing the molecular relaxation process by only measuring acoustic velocity, without the necessity of obtaining acoustic absorption. The method is based on the fact that the frequency-dependent velocity dispersion of a multi-relaxation process in a gas is the serial connection of the dispersions of interior single-relaxation processes. Thus, one can capture the relaxation times and relaxation strengths of N decomposed single-relaxation dispersions to reconstruct the entire multi-relaxation dispersion using the measurements of acoustic velocity at 2N  +  1 frequencies. The reconstructed dispersion spectra are in good agreement with experimental data for various gases and mixtures. The simulations also demonstrate the robustness of our reconstructive method.

  13. Relaxed states of tokamak plasmas

    International Nuclear Information System (INIS)

    Kucinski, M.Y.; Okano, V.

    1993-01-01

    The relaxed states of tokamak plasmas are studied. It is assumed that the plasma relaxes to a quasi-steady state which is characterized by a minimum entropy production rate, compatible with a number of prescribed conditions and pressure balance. A poloidal current arises naturally due to the anisotropic resistivity. The minimum entropy production theory is applied, assuming the pressure equilibrium as fundamental constraint on the final state. (L.C.J.A.)

  14. Negative magnetic relaxation in superconductors

    Directory of Open Access Journals (Sweden)

    Krasnoperov E.P.

    2013-01-01

    Full Text Available It was observed that the trapped magnetic moment of HTS tablets or annuli increases in time (negative relaxation if they are not completely magnetized by a pulsed magnetic field. It is shown, in the framework of the Bean critical-state model, that the radial temperature gradient appearing in tablets or annuli during a pulsed field magnetization can explain the negative magnetic relaxation in the superconductor.

  15. Auditory driving of the autonomic nervous system: Listening to theta-frequency binaural beats post-exercise increases parasympathetic activation and sympathetic withdrawal

    OpenAIRE

    Patrick eMcConnell; Patrick eMcConnell; Brett eFroeliger; Eric L. Garland; Jeffrey C. Ives; Gary A. Sforzo

    2014-01-01

    Binaural beats are an auditory illusion perceived when two or more pure tones of similar frequencies are presented dichotically through stereo headphones. Although this phenomenon is thought to facilitate state changes (e.g., relaxation), few empirical studies have reported on whether binaural beats produce changes in autonomic arousal. Therefore, the present study investigated the effects of binaural beating on autonomic dynamics (heart-rate variability (HRV)) during post-exercise relaxation...

  16. Auditory driving of the autonomic nervous system: Listening to theta-frequency binaural beats post-exercise increases parasympathetic activation and sympathetic withdrawal

    OpenAIRE

    McConnell, Patrick A.; Froeliger, Brett; Garland, Eric L.; Ives, Jeffrey C.; Sforzo, Gary A.

    2014-01-01

    Binaural beats are an auditory illusion perceived when two or more pure tones of similar frequencies are presented dichotically through stereo headphones. Although this phenomenon is thought to facilitate state changes (e.g., relaxation), few empirical studies have reported on whether binaural beats produce changes in autonomic arousal. Therefore, the present study investigated the effects of binaural beating on autonomic dynamics [heart rate variability (HRV)] during post-exercise relaxation...

  17. Auditory driving of the autonomic nervous system: Listening to theta-frequency binaural beats post-exercise increases parasympathetic activation and sympathetic withdrawal.

    Science.gov (United States)

    McConnell, Patrick A; Froeliger, Brett; Garland, Eric L; Ives, Jeffrey C; Sforzo, Gary A

    2014-01-01

    Binaural beats are an auditory illusion perceived when two or more pure tones of similar frequencies are presented dichotically through stereo headphones. Although this phenomenon is thought to facilitate state changes (e.g., relaxation), few empirical studies have reported on whether binaural beats produce changes in autonomic arousal. Therefore, the present study investigated the effects of binaural beating on autonomic dynamics [heart rate variability (HRV)] during post-exercise relaxation. Subjects (n = 21; 18-29 years old) participated in a double-blind, placebo-controlled study during which binaural beats and placebo were administered over two randomized and counterbalanced sessions (within-subjects repeated-measures design). At the onset of each visit, subjects exercised for 20-min; post-exercise, subjects listened to either binaural beats ('wide-band' theta-frequency binaural beats) or placebo (carrier tones) for 20-min while relaxing alone in a quiet, low-light environment. Dependent variables consisted of high-frequency (HF, reflecting parasympathetic activity), low-frequency (LF, reflecting sympathetic and parasympathetic activity), and LF/HF normalized powers, as well as self-reported relaxation. As compared to the placebo visit, the binaural-beat visit resulted in greater self-reported relaxation, increased parasympathetic activation and increased sympathetic withdrawal. By the end of the 20-min relaxation period there were no observable differences in HRV between binaural-beat and placebo visits, although binaural-beat associated HRV significantly predicted subsequent reported relaxation. Findings suggest that listening to binaural beats may exert an acute influence on both LF and HF components of HRV and may increase subjective feelings of relaxation.

  18. Auditory driving of the autonomic nervous system: Listening to theta-frequency binaural beats post-exercise increases parasympathetic activation and sympathetic withdrawal

    Directory of Open Access Journals (Sweden)

    Patrick eMcConnell

    2014-11-01

    Full Text Available Binaural beats are an auditory illusion perceived when two or more pure tones of similar frequencies are presented dichotically through stereo headphones. Although this phenomenon is thought to facilitate state changes (e.g., relaxation, few empirical studies have reported on whether binaural beats produce changes in autonomic arousal. Therefore, the present study investigated the effects of binaural beating on autonomic dynamics (heart-rate variability (HRV during post-exercise relaxation. Subjects (n = 21; 18-29 years old participated in a double-blind, placebo-controlled study during which binaural beats and placebo were administered over two randomized and counterbalanced sessions (within-subjects repeated-measures design. At the onset of each visit, subjects exercised for 20-min; post-exercise, subjects listened to either binaural beats (‘wide-band’ theta-frequency binaural beats or placebo (carrier tone for 20-min while relaxing alone in a quiet, low-light environment. Dependent variables consisted of high frequency (HF, reflecting parasympathetic activity, low frequency (LF, reflecting sympathetic and parasympathetic activity and LF/HF normalized powers, as well as self-reported relaxation. As compared to the placebo visit, the binaural beat visit resulted in greater self-reported relaxation, as well as increased parasympathetic activation and sympathetic withdrawal. By the end of the 20-min relaxation period there were no observable differences in HRV between binaural beat and placebo visits, although binaural-beat associated HRV significantly predicted subsequent reported relaxation. Findings suggest that listening to binaural beats may exert an acute influence on both LF and HF components of HRV and may increase subjective feelings of relaxation.

  19. Parameterization of NMR relaxation curves in terms of logarithmic moments of the relaxation time distribution.

    Science.gov (United States)

    Petrov, Oleg V; Stapf, Siegfried

    2017-06-01

    This work addresses the problem of a compact and easily comparable representation of multi-exponential relaxation data. It is often convenient to describe such data in a few parameters, all being of physical significance and easy to interpret, and in such a way that enables a model-free comparison between different groups of samples. Logarithmic moments (LMs) of the relaxation time constitute a set of parameters which are related to the characteristic relaxation time on the log-scale, the width and the asymmetry of an underlying distribution of exponentials. On the other hand, the calculation of LMs does not require knowing the actual distribution function and is reduced to a numerical integration of original data. The performance of this method has been tested on both synthetic and experimental NMR relaxation data which differ in a signal-to-noise ratio, the sampling range and the sampling rate. The calculation of two lower-order LMs, the log-mean time and the log-variance, has proved robust against deficiencies of the experiment such as scattered data point and incomplete sampling. One may consider using them as such to monitor formation of a heterogeneous structure, e.g., in phase separation, vitrification, polymerization, hydration, aging, contrast agent propagation processes. It may also assist in interpreting frequency and temperature dependences of relaxation, revealing a crossover from slow to fast exchange between populations. The third LM was found to be a less reliable quantity due to its susceptibility to the noise and must be used with caution. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Parameterization of NMR relaxation curves in terms of logarithmic moments of the relaxation time distribution

    Science.gov (United States)

    Petrov, Oleg V.; Stapf, Siegfried

    2017-06-01

    This work addresses the problem of a compact and easily comparable representation of multi-exponential relaxation data. It is often convenient to describe such data in a few parameters, all being of physical significance and easy to interpret, and in such a way that enables a model-free comparison between different groups of samples. Logarithmic moments (LMs) of the relaxation time constitute a set of parameters which are related to the characteristic relaxation time on the log-scale, the width and the asymmetry of an underlying distribution of exponentials. On the other hand, the calculation of LMs does not require knowing the actual distribution function and is reduced to a numerical integration of original data. The performance of this method has been tested on both synthetic and experimental NMR relaxation data which differ in a signal-to-noise ratio, the sampling range and the sampling rate. The calculation of two lower-order LMs, the log-mean time and the log-variance, has proved robust against deficiencies of the experiment such as scattered data point and incomplete sampling. One may consider using them as such to monitor formation of a heterogeneous structure, e.g., in phase separation, vitrification, polymerization, hydration, aging, contrast agent propagation processes. It may also assist in interpreting frequency and temperature dependences of relaxation, revealing a crossover from slow to fast exchange between populations. The third LM was found to be a less reliable quantity due to its susceptibility to the noise and must be used with caution.

  1. Relaxation mechanism of the hydrated electron.

    Science.gov (United States)

    Elkins, Madeline H; Williams, Holly L; Shreve, Alexander T; Neumark, Daniel M

    2013-12-20

    The relaxation dynamics of the photoexcited hydrated electron have been subject to conflicting interpretations. Here, we report time-resolved photoelectron spectra of hydrated electrons in a liquid microjet with the aim of clarifying ambiguities from previous experiments. A sequence of three ultrashort laser pulses (~100 femtosecond duration) successively created hydrated electrons by charge-transfer-to-solvent excitation of dissolved anions, electronically excited these electrons via the s→p transition, and then ejected them into vacuum. Two distinct transient signals were observed. One was assigned to the initially excited p-state with a lifetime of ~75 femtoseconds, and the other, with a lifetime of ~400 femtoseconds, was attributed to s-state electrons just after internal conversion in a nonequilibrated solvent environment. These assignments support the nonadiabatic relaxation model.

  2. Thermal Annealing induced relaxation of compressive strain in porous GaN structures

    KAUST Repository

    Ben Slimane, Ahmed; Najar, Adel; Ng, Tien Khee; Ooi, Boon S.

    2012-01-01

    The effect of annealing on strain relaxation in porous GaN fabricated using electroless chemical etching is presented. The Raman shift of 1 cm-1 in phonon frequency of annealed porous GaN with respect to as-grown GaN corresponds to a relaxation

  3. F19 relaxation in non-magnetic hexafluorides

    International Nuclear Information System (INIS)

    Rigny, P.

    1969-01-01

    The interesting properties of the fluorine magnetic resonance in the hexafluorides of molybdenum, tungsten and uranium, are very much due to large anisotropies of the chemical shift tensors. In the solid phases these anisotropies, the values of which are deduced from line shape studies, allow one to show that the molecules undergo hindered rotations about the metal atom. The temperature and frequency dependence of the fluorine longitudinal relaxation times shows that the relaxation is due to the molecular motion. The dynamical parameters of this motion are then deduced from the complete study of the fluorine relaxation in the rotating frame. In the liquid phases, the existence of anisotropies allows an estimation of the different contributions to the relaxation. In particular, the frequency and temperature dependence of the relaxation shows it to be dominated by the spin-rotation interaction. We have shown that the strength of this interaction can be deduced from the chemical shifts, and the angle through which the molecule rotates quasi-freely can be determined. In the hexafluorides, this angle is roughly one radian at 70 C, and with the help of this value, the friction coefficients which describe the intermolecular interactions are discussed. (author) [fr

  4. Inconsistency in Reporting Abstention and Heavy Drinking Frequency: Associations with Sex and Socioeconomic Status, and Potential Impacts

    Science.gov (United States)

    Kydd, Robyn M.; Connor, Jennie

    2015-01-01

    Aims: To describe inconsistencies in reporting past-year drinking status and heavy drinking occasions (HDOs) on single questions from two different instruments, and to identify associated characteristics and impacts. Methods: We compared computer-presented Alcohol Use Disorder Identification Test-Consumption (AUDIT-C) with categorical response options, and mental health interview (MHI) with open-ended consumption questions, completed on the same day. Participants were 464 men and 459 women aged 38 (91.7% of surviving birth cohort members). Differences in dichotomous single-item measures of abstention and HDO frequency, associations of inconsistent reporting with sex, socioeconomic status (SES) and survey order, and impacts of instrument choice on associations of alcohol with sex and SES were examined. Results: The AUDIT-C drinking frequency question estimated higher past-year abstention prevalence (AUDIT = 7.6%, MHI = 5.4%), with one-third of AUDIT-C abstainers being MHI drinkers. Only AUDIT-C produced significant sex differences in abstainer prevalence. Inconsistencies in HDO classifications were bidirectional, but with fewer HDOs reported on the MHI than AUDIT-C question. Lower SES was associated with inconsistency in abstention and weekly+ HDOs. Abstention and higher HDO frequency were associated with lower SES overall, but sex-specific associations differed by instrument. Conclusions: In this context, data collection method affected findings, with inconsistencies in abstention reports having most impact. Future studies should: (a) confirm self-reported abstention; (b) consider piloting data collection methods in target populations; (c) expect impacts of sex and SES on measurements and analyses. PMID:25648932

  5. Reported frequency of physical activity in a large epidemiological study: relationship to specific activities and repeatability over time

    Directory of Open Access Journals (Sweden)

    Reeves Gillian K

    2011-06-01

    Full Text Available Abstract Background How overall physical activity relates to specific activities and how reported activity changes over time may influence interpretation of observed associations between physical activity and health. We examine the relationships between various physical activities self-reported at different times in a large cohort study of middle-aged UK women. Methods At recruitment, Million Women Study participants completed a baseline questionnaire including questions on frequency of strenuous and of any physical activity. About 3 years later 589,896 women also completed a follow-up questionnaire reporting the hours they spent on a range of specific activities. Time spent on each activity was used to estimate the associated excess metabolic equivalent hours (MET-hours and this value was compared across categories of physical activity reported at recruitment. Additionally, 18,655 women completed the baseline questionnaire twice, at intervals of up to 4 years; repeatability over time was assessed using the weighted kappa coefficient (κweighted and absolute percentage agreement. Results The average number of hours per week women reported doing specific activities was 14.0 for housework, 4.5 for walking, 3.0 for gardening, 0.2 for cycling, and 1.4 for all strenuous activity. Time spent and the estimated excess MET-hours associated with each activity increased with increasing frequency of any or strenuous physical activity reported at baseline (tests for trend, P weighted = 0.71 for questionnaires administered less than 6 months apart, and 52% (κweighted = 0.51 for questionnaires more than 2 years apart. Corresponding values for any physical activity were 57% (κweighted = 0.67 and 47% (κweighted = 0.58. Conclusions In this cohort, responses to simple questions on the frequency of any physical activity and of strenuous activity asked at baseline were associated with hours spent on specific activities and the associated estimated excess MET

  6. A moving mesh method with variable relaxation time

    OpenAIRE

    Soheili, Ali Reza; Stockie, John M.

    2006-01-01

    We propose a moving mesh adaptive approach for solving time-dependent partial differential equations. The motion of spatial grid points is governed by a moving mesh PDE (MMPDE) in which a mesh relaxation time \\tau is employed as a regularization parameter. Previously reported results on MMPDEs have invariably employed a constant value of the parameter \\tau. We extend this standard approach by incorporating a variable relaxation time that is calculated adaptively alongside the solution in orde...

  7. The Frequency of Reporting Ethical Issues in Human Subject Articles Published in Iranian Medical Journals: 2009-2013.

    Science.gov (United States)

    Astaneh, Behrooz; Khani, Parisa

    2017-11-10

    Researchers should strictly consider the participants' rights. They are required to document such protections as an ethical approval of the study proposal, the obtaining "informed consent", the authors' "conflict of interests", and the source of "financial support" in the published articles. The purpose of this study was to assess the frequency of reporting ethical issues in human subject articles published in Iranian medical journals during 2009-2013. In this cross-sectional study, we randomly reviewed 1460 human subject articles published in Iranian medical journals during 2009-2013 in two Persian and English language groups. Data collection was carried out by assessing articles, focusing on the documentation "ethics committee approval", patients' "informed consent", "financial support", "confidentiality", and "conflict of interest". Of 1460 evaluated articles, 443 (30.3%) reported "ethics committee approval", 686 (47.0%) reported "informed consent", 594 (40.7%) reported "financial support", and 341 (23.4%) reported "conflict of interest". 13% of the articles referred to patients' confidentiality in their text. There was a significant association between these ethical documentations and the year of publication. Articles published in English language journals reported "ethics committee approval", "financial support", and "conflict of interest" significantly more than Persian language journals, but the frequency of "informed consent" was similar. Ethical documentation rate in Iranian medical journals is not up to the expected standards of reputable journals which might be related to a lack of awareness and the education of the authors and the journal's editors. Precise reporting of ethical considerations in medical articles by authors are recommended. It is suggested journals and policymakers pay more attention to reporting this issue while providing standard guidelines in this regard.

  8. [Frequency of cervical epithelial lesions reported in the Regional Laboratory of Exfoliative Cytology in Jalisco].

    Science.gov (United States)

    González-López, Sergio; Martínez-Silva, María G; Hernández-Hernández, Dulce M; Aguilar-Lemarroy, Adriana; Jave-Suárez, Luis Felipe

    2015-01-01

    The Official Mexican Norm for the prevention, treatment and control of Cervical Cancer (CC) indicates that the Papanicolau (Pap) is the procedure for the detection of this neoplasia; therefore, it is of interest to know the prevalence of suspected cases by this technique in Mexican population. In this study, we show the diagnosed cases in the State of Jalisco, México. A retrospective study was made to the samples that arrived for their analysis to the Laboratorio Regional de Citología Exfoliativa (LARCE), of the Instituto Mexicano del Seguro Social (IMSS) in Guadalajara, Jalisco. We considered all cases from January 2010 to December 2012. We analyzed 188 095 cases, from which 5.3 % had a diagnosis of low dysplasia, 0.18 % of moderated dysplasia and 0.05 % of high dysplasia. Microinvasive and invasive cancer showed a low frequency (0.03 %). The frequency of abnormal findings identified by vaginal cervical cytology is relatively low. The number of inadequate and limited samples for cytological assessment is high; there is a high proportion of women attending for the first time in life to cytology evaluation in older age groups.

  9. Nuclear spin-lattice relaxation in carbon nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Panich, A.M., E-mail: pan@bgu.ac.i [Department of Physics, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel); Sergeev, N.A. [Institute of Physics, University of Szczecin, 70-451 Szczecin (Poland)

    2010-04-15

    Interpretation of nuclear spin-lattice relaxation data in the carbon nanostructures is usually based on the analysis of fluctuations of dipole-dipole interactions of nuclear spins and anisotropic electron-nuclear interactions responsible for chemical shielding, which are caused by molecular dynamics. However, many nanocarbon systems such as fullerene and nanotube derivatives, nanodiamonds and carbon onions reveal noticeable amount of paramagnetic defects with unpaired electrons originating from dangling bonds. The interaction between nuclear and electron spins strongly influences the nuclear spin-lattice relaxation, but usually is not taken into account, thus the relaxation data are not correctly interpreted. Here we report on the temperature dependent NMR spectra and spin-lattice relaxation measurements of intercalated fullerenes C{sub 60}(MF{sub 6}){sub 2} (M=As and Sb), where nuclear relaxation is caused by both molecular rotation and interaction between nuclei and unpaired electron spins. We present a detailed theoretical analysis of the spin-lattice relaxation data taking into account both these contributions. Good agreement between the experimental data and calculations is obtained. The developed approach would be useful in interpreting the NMR relaxation data in different nanostructures and their intercalation compounds.

  10. Relaxation dynamics of glass transition in PMMA + SWCNT composites by temperature-modulated DSC

    Science.gov (United States)

    Pradhan, N. R.; Iannacchione, G. S.

    2010-03-01

    The experimental technique offered by temperature-modulated differential scanning calorimeter (TMDSC) used to investigate the thermal relaxation dynamics through the glass transition as a function of frequency was studied for pure PMMA and PMMA-single wall carbon nanotubes (SWCNTs) composites. A strong dependence of the temperature dependence peak in the imaginary part of complex heat capacity (Tmax) is found during the transition from the glass-like to the liquid-like region. The frequency dependence of Tmax of the imaginary part of heat capacity (Cp) is described by Arrhenius law. The activation energy obtained from the fitting shows increases while the characteristic relaxation time decreases with increasing mass fraction (phim) of SWCNTs. The dynamics of the composites during glass transition, at slow and high scan rates, are also the main focus of this experimental study. The change in enthalpy during heating and cooling is also reported as a function of scan rate and frequency of temperature modulation. The glass transition temperature (Tg) shows increases with increasing frequency of temperature modulation and phim of SWCNTs inside the polymer host. Experimental results show that Tg is higher at higher scan rates but as the frequency of temperature modulation increases, the Tg values of different scan rates coincide with each other and alter the scan rate dependence. From the imaginary part of heat capacity, it is obvious that Tmax is not the actual glass transition temperature of pure polymer but Tmax and Tg values can be superimposed when phim increases in the polymer host or when the sample undergoes a transition with a certain frequency of temperature modulation.

  11. Development of high power radio frequency components for fusion plasma heating. Final report, Revision 3

    International Nuclear Information System (INIS)

    1997-01-01

    The purpose of this CRADA was to develop advanced microwave heating systems for both ion cyclotron heating and electron cyclotron heating for magnetic fusion reactors. This involved low-frequency (UHF), high-power (millimeter-wave) microwave components, such as antennas, windows, and matching elements. This CRADA also involved developing conceptual designs for new microwave sources. General Atomics built and tested the distributed cooled window and provided LLNL with transmission and reflection test data in order to then benchmark the EM computer codes. The combline antenna built and analyzed by LLNL was based on a GA design. GA provided LLNL with a number of niobium plates for hot pressing and provided the necessary guidance to allow successful bonding. GA representatives were on site at LLNL on numerous occasions to consult and give guidance on the ferroelectric tuner, combline antenna and distributed window analysis

  12. Theoretical studies of the heating of toroidal plasmas with radio frequency electromagnetic radiation. Final report

    International Nuclear Information System (INIS)

    Glasser, A.H.; Swanson, D.G.; Wersinger, J.M.

    1982-01-01

    The continuation of a program of theoretical studies of the heating of toroidal plasmas with radio frequency (RF) electromagnetic radiation is proposed. Funding for this project first began on September 3, 1981, and will expire on April 2, 1982. A summary of the principal accomplishments of the first five months of the project is presented. These include the acquisition of computer terminals and modems, the implementation of existing codes on the MFECC C Cray Computer, the extension of the LHTOR lower hybrid toroidal ray tracing code to the full electromagnetic dispersion relation, the implementation of graphic output from the code, the beginning of extensive parameter studies, the beginning of an analytical treatment of the mode conversion layer associated with singular harmonic absorption, and the introduction of a graduate student into the program

  13. Experimental studies of radio frequency waves and confinement in the Auburn Torsatron. Progress report

    International Nuclear Information System (INIS)

    Swanson, D.G.

    1985-01-01

    The first year of operation of the Auburn Torsatron has resulted in the majority of the basic operating systems becoming operational or nearly operational. The diagnostic systems now include two microwave interferometers, a monochrometer, several probes and photodiodes. The plasma is produced by any of three sources: electron cyclotron heating with a cw power of 1 kW, low frequency rf heating with power soon to come up to 10 kW cw, and a pulsed washer-stack gun. The magnetic field studies have mapped the field surfaces and several corrections have been made to center the plasma. The ion-cyclotron source and antenna are nearly ready for experiments to begin

  14. Quasiparticle relaxation in Heavy Fermions studied using Inverse Fourier Transform of optical conductivity

    International Nuclear Information System (INIS)

    Dordevic, S.V.

    2012-01-01

    Inverse Fourier Transform of optical conductivity is used for studies of quasiparticle relaxation in Heavy Fermions in time domain. We demonstrate the usefulness of the procedure on model spectra and then use it to study quasiparticle relaxation in two Heavy Fermions YbFe 4 Sb 12 and CeRu 4 Sb 12 . Optical conductivity in time domain reveals details of quasiparticle relaxation close to the Fermi level, not readily accessible from the spectra in the frequency domain. In particular, we find that the relaxation of heavy quasiparticles does not start instantaneously, but typically after a few hundred femto-seconds.

  15. Proton NMR relaxation in hydrous melts

    International Nuclear Information System (INIS)

    Braunstein, J.; Bacarella, A.L.; Benjamin, B.M.; Brown, L.L.; Girard, C.

    1976-01-01

    Pulse and continuous wave NMR measurements are reported for protons in hydrous melts of calcium nitrate at temperatures between -4 and 120 0 C. Although measured in different temperature ranges, spin-lattice (T 1 ) and spin-spin (T 2 ) relaxation times appear to be nearly equal to each other and proportional to the self-diffusion coefficients of solute metal cations such as Cd 2+ . At temperatures near 50 0 C, mean Arrhenius coefficients Δ H/sub T 1 / (kcal/mol) are 7.9, 7.3, and 4.8, respectively, for melts containing 2.8, 4.0, and 8.0 moles of water per mole of calcium nitrate, compared to 4.6 kcal/mol for pure water. Temperature dependence of T 1 and T 2 in Ca(NO 3 ) 2 -2.8 H 2 O between -4 and 120 0 C are non-Arrhenius and can be represented by a Fulcher-type equation with a ''zero mobility temperature'' (T 0 ) of 225 0 K, close to the value of T 0 for solute diffusion, electrical conductance and viscosity. Resolution of the relaxation rates into correlation times for intramolecular (rotational) and intermolecular (translational) diffusional motion is discussed in terms of the Bloembergen-Purcell-Pound and more recent models for dipolar relaxation

  16. Dispersion of Sound in Dilute Suspensions with Nonlinear Particle Relaxation

    Science.gov (United States)

    Kandula, Max

    2010-01-01

    The theory accounting for nonlinear particle relaxation (viscous and thermal) has been applied to the prediction of dispersion of sound in dilute suspensions. The results suggest that significant deviations exist for sound dispersion between the linear and nonlinear theories at large values of Omega(Tau)(sub d), where Omega is the circular frequency, and Tau(sub d) is the Stokesian particle relaxation time. It is revealed that the nonlinear effect on the dispersion coefficient due to viscous contribution is larger relative to that of thermal conduction

  17. Introduction to electronic relaxation in solids: mechanisms and measuring techniques

    International Nuclear Information System (INIS)

    Bonville, P.

    1983-01-01

    The fluctuations of electronic magnetic moments in solids may be investigated by several techniques, either electronic or nuclear. This paper is an introduction of the most frequently encountered paramagnetic relaxation mechanisms (phonons, conduction electrons, exchange or dipolar interactions) in condensed matter, and to the different techniques used for measuring relaxation frequencies: electronic paramagnetic resonance, nuclear magnetic resonance, Moessbauer spectroscopy, inelastic neutron scattering, measurement of longitudinal ac susceptibility and γ-γ perturbed angular correlations. We mainly focus our attention on individual ionic fluctuation spectra, the majority of the experimental work refered to concerning rare earth systems [fr

  18. Operation of the cryotron relaxation generator in solid argon and hydrogen

    International Nuclear Information System (INIS)

    Rakhubvsky, V.A.

    2008-01-01

    The research results of the cryotron relaxation generator (CRG) operation in solid argon, normal hydrogen and parahydrogen have been given. The frequency transition times for CRG at different values of cooling the solid gas have been measured

  19. Levitation force relaxation under reloading in a HTS Maglev system

    International Nuclear Information System (INIS)

    He Qingyong; Wang Jiasu; Wang Suyu; Wang Jiansi; Dong Hao; Wang Yuxin; Shao Senhao

    2009-01-01

    The loading capacity of the high-temperature superconducting (HTS) Maglev vehicle is an important parameter in the practical application. It is closely related to the levitation force of the HTS bulk. Many papers reported that the levitation force showed the relaxation characteristic. Because different loads cause different levitation gaps and different applied magnetic fields, the levitation force relaxations under the different loads are not the same. In terms of cylindrical YBCO bulk levitated over the permanent magnetic guideway, the relationship between the levitation force relaxation and the reloading is investigated experimentally in this paper. The decrement, the decrement rate and the relaxation rate of the levitation force are calculated, respectively. This work might be helpful for studying the loading capacity of the HTS Maglev vehicle

  20. Levitation force relaxation under reloading in a HTS Maglev system

    Energy Technology Data Exchange (ETDEWEB)

    He Qingyong [Applied Superconductivity Laboratory, M/S 152, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)], E-mail: hedoubling@gmail.com; Wang Jiasu; Wang Suyu; Wang Jiansi; Dong Hao; Wang Yuxin; Shao Senhao [Applied Superconductivity Laboratory, M/S 152, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)

    2009-02-01

    The loading capacity of the high-temperature superconducting (HTS) Maglev vehicle is an important parameter in the practical application. It is closely related to the levitation force of the HTS bulk. Many papers reported that the levitation force showed the relaxation characteristic. Because different loads cause different levitation gaps and different applied magnetic fields, the levitation force relaxations under the different loads are not the same. In terms of cylindrical YBCO bulk levitated over the permanent magnetic guideway, the relationship between the levitation force relaxation and the reloading is investigated experimentally in this paper. The decrement, the decrement rate and the relaxation rate of the levitation force are calculated, respectively. This work might be helpful for studying the loading capacity of the HTS Maglev vehicle.

  1. 129 Xe NMR Relaxation-Based Macromolecular Sensing

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Muller D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Dao, Phuong [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Jeong, Keunhong [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Slack, Clancy C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Vassiliou, Christophoros C. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Finbloom, Joel A. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Francis, Matthew B. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Wemmer, David E. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Biosciences Division; Pines, Alexander [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    2016-07-29

    A 129Xe NMR relaxation-based sensing approach is reported on that exploits changes in the bulk xenon relaxation rate induced by slowed tumbling of a cryptophane-based sensor upon target binding. The amplification afforded by detection of the bulk dissolved xenon allows sensitive detection of targets. The sensor comprises a xenon-binding cryptophane cage, a target interaction element, and a metal chelating agent. Xenon associated with the target-bound cryptophane cage is rapidly relaxed and then detected after exchange with the bulk. Here we show that large macromolecular targets increase the rotational correlation time of xenon, increasing its relaxation rate. Upon binding of a biotin-containing sensor to avidin at 1.5 μM concentration, the free xenon T2 is reduced by a factor of 4.

  2. Peeling mode relaxation ELM model

    International Nuclear Information System (INIS)

    Gimblett, C. G.

    2006-01-01

    This paper discusses an approach to modelling Edge Localised Modes (ELMs) in which toroidal peeling modes are envisaged to initiate a constrained relaxation of the tokamak outer region plasma. Relaxation produces both a flattened edge current profile (which tends to further destabilise a peeling mode), and a plasma-vacuum negative current sheet which has a counteracting stabilising influence; the balance that is struck between these two effects determines the radial extent (rE) of the ELM relaxed region. The model is sensitive to the precise position of the mode rational surfaces to the plasma surface and hence there is a 'deterministic scatter' in the results that has an accord with experimental data. The toroidal peeling stability criterion involves the edge pressure, and using this in conjunction with predictions of rE allows us to evaluate the ELM energy losses and compare with experiment. Predictions of trends with the edge safety factor and collisionality are also made

  3. Evaluation of the Problem Behavior Frequency Scale-Teacher Report Form for Assessing Behavior in a Sample of Urban Adolescents.

    Science.gov (United States)

    Farrell, Albert D; Goncy, Elizabeth A; Sullivan, Terri N; Thompson, Erin L

    2018-02-01

    This study evaluated the structure and validity of the Problem Behavior Frequency Scale-Teacher Report Form (PBFS-TR) for assessing students' frequency of specific forms of aggression and victimization, and positive behavior. Analyses were conducted on two waves of data from 727 students from two urban middle schools (Sample 1) who were rated by their teachers on the PBFS-TR and the Social Skills Improvement System (SSIS), and on data collected from 1,740 students from three urban middle schools (Sample 2) for whom data on both the teacher and student report version of the PBFS were obtained. Confirmatory factor analyses supported first-order factors representing 3 forms of aggression (physical, verbal, and relational), 3 forms of victimization (physical, verbal and relational), and 2 forms of positive behavior (prosocial behavior and effective nonviolent behavior), and higher-order factors representing aggression, victimization, and positive behavior. Strong measurement invariance was established over gender, grade, intervention condition, and time. Support for convergent validity was found based on correlations between corresponding scales on the PBFS-TR and teacher ratings on the SSIS in Sample 1. Significant correlations were also found between teacher ratings on the PBFS-TR and student ratings of their behavior on the Problem Behavior Frequency Scale-Adolescent Report (PBFS-AR) and a measure of nonviolent behavioral intentions in Sample 2. Overall the findings provided support for the PBFS-TR and suggested that teachers can provide useful data on students' aggressive and prosocial behavior and victimization experiences within the school setting. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  4. Performance report on the ground test accelerator radio-frequency quadrupole

    International Nuclear Information System (INIS)

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Brown, S.; Cole, R.; Connolly, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.

    1994-01-01

    The Ground Test Accelerator (GTA) uses a radio-frequency quadrupole (RFQ) to bunch and accelerate a 35 keV input beam to a final energy of 2.5 MeV. Most measured parameters of the GTA RFQ agreed with simulated predictions. The relative shape of the transmission versus the vane-voltage relationship and the Courant-Snyder (CS) parameters of the output beam's transverse and longitudinal phase spaces agreed well with predictions. However, the transmission of the RFQ was significantly lower than expected. Improved simulation studies included image charges and multipole effects in the RFQ. Most of the predicted properties of the RFQ, such as input matched-beam conditions and output-beam shapes were unaffected by these additional effects. However, the comparison of measured with predicted absolute values of transmitted beam was much improved by the inclusion of these effects in the simulations. The comparison implied a value for the input emittance that is consistent with measurements

  5. Low frequency RF current drive. Final report, January 1, 1988 - May 31, 1997

    International Nuclear Information System (INIS)

    Hershkowitz, N.

    1999-01-01

    This report starts with a summary of research done on the Phaedrus Tandom Mirror concept and how this research led to the design and construction of the Phaedrus-T Tokamak. Next it gives a more detailed description of the results from the last four years of research, which include the following areas: (1) first experimental demonstration of AWCD (Alfven Wave Current Drive); (2) current drive location and loop voltage response; (3) trapping and current drive efficiency; and (4) reflectometry

  6. Frequency of self-reported sexual aggression and victimization in Brazil: a literature review

    Directory of Open Access Journals (Sweden)

    Lylla Winzer

    2016-01-01

    Full Text Available Abstract: The lack of official data on rape has been a challenge for researchers in Brazil. Two recently published studies were based on law enforcement and medical records. Although these studies represent important progress in research on rape in the country, they have several limitations. In order to obtain more realistic rates, the current article reviews Brazilian studies on self-reported sexual aggression and victimization in individuals over 14 years of age. Forty-one studies were identified through electronic searches and reference verification. From 1% to 40% of women and 1% to 35% of men reported some form of victimization in the previous year. The male perpetration incidence ranged from 2% to 44%. Despite the wide variability, these rates were much higher than those provided by official data. The results suggest that sexual orientation is associated with vulnerability. Mixed findings were found concerning race. Most studies were based on convenience samples and focused on female victimization. Male victimization has received increasing attention, but studies on self-reported perpetration are still limited.

  7. Associations between communication climate and the frequency of medical error reporting among pharmacists within an inpatient setting.

    Science.gov (United States)

    Patterson, Mark E; Pace, Heather A; Fincham, Jack E

    2013-09-01

    Although error-reporting systems enable hospitals to accurately track safety climate through the identification of adverse events, these systems may be underused within a work climate of poor communication. The objective of this analysis is to identify the extent to which perceived communication climate among hospital pharmacists impacts medical error reporting rates. This cross-sectional study used survey responses from more than 5000 pharmacists responding to the 2010 Hospital Survey on Patient Safety Culture (HSOPSC). Two composite scores were constructed for "communication openness" and "feedback and about error," respectively. Error reporting frequency was defined from the survey question, "In the past 12 months, how many event reports have you filled out and submitted?" Multivariable logistic regressions were used to estimate the likelihood of medical error reporting conditional upon communication openness or feedback levels, controlling for pharmacist years of experience, hospital geographic region, and ownership status. Pharmacists with higher communication openness scores compared with lower scores were 40% more likely to have filed or submitted a medical error report in the past 12 months (OR, 1.4; 95% CI, 1.1-1.7; P = 0.004). In contrast, pharmacists with higher communication feedback scores were not any more likely than those with lower scores to have filed or submitted a medical report in the past 12 months (OR, 1.0; 95% CI, 0.8-1.3; P = 0.97). Hospital work climates that encourage pharmacists to freely communicate about problems related to patient safety is conducive to medical error reporting. The presence of feedback infrastructures about error may not be sufficient to induce error-reporting behavior.

  8. Three-dimensional self-consistent simulations of multipacting in superconducting radio frequency cavities. Final Report

    International Nuclear Information System (INIS)

    Nieter, Chet

    2010-01-01

    Superconducting radio frequency (SRF) cavities are a popular choice among researchers designing new accelerators because of the reduced power losses due to surface resistance. However, SRF cavities still have unresolved problems, including the loss of power to stray electrons. Sources of these electrons are field emission from the walls and ionization of background gas, but the predominant source is secondary emission yield (SEY) from electron impact. When the electron motion is in resonance with the cavity fields the electrons strike the cavity surface repeatedly creating a resonant build up of electrons referred to as multipacting. Cavity shaping has successfully reduced multipacting for cavities used in very high energy accelerators. However, multipacting is still a concern for the cavity power couplers, where shaping is not possible, and for cavities used to accelerate particles at moderate velocities. This Phase II project built upon existing models in the VORPAL simulation framework to allow for simulations of multipacting behavior in SRF cavities and their associated structures. The technical work involved allowed existing models of secondary electron generation to work with the complex boundary conditions needed to model the cavity structures. The types of data produced by VORPAL were also expanded to include data common used by cavity designers to evaluate cavity performance. Post-processing tools were also modified to provide information directly related to the conditions that produce multipacting. These new methods were demonstrated by running simulations of a cavity design being developed by researchers at Jefferson National Laboratory to attempt to identify the multipacting that would be an issue for the cavity design being considered. These simulations demonstrate that VORPAL now has the capabilities to assist researchers working with SRF cavities to understand and identify possible multipacting issues with their cavity designs.

  9. Electrocorticographic Frequency Alteration Mapping of Speech Cortex during an Awake Craniotomy: Case Report

    Science.gov (United States)

    Breshears, J.; Sharma, M.; Anderson, N.R.; Rashid, S.; Leuthardt, E.C.

    2010-01-01

    Objective Traditional electrocortical stimulation (ECS) mapping is limited by the lengthy serial investigation (one location at a time) and the risk of afterdischarges in localizing eloquent cortex. Electrocorticographic frequency alteration mapping (EFAM) allows the parallel investigation of many cortical sites in much less time and with no risk of afterdischarges because of its passive nature. We examined its use with ECS in the context of language mapping during an awake craniotomy for a tumor resection. Clinical Presentation The patient was a 61-year-old right-handed Caucasian male who presented with headache and mild aphasia. Imaging demonstrated a 3-cm cystic mass in the posterior temporal-parietal lobe. The patient underwent an awake craniotomy for the mapping of his speech cortex and resection of the mass. Intervention Using a 32-contact electrode array, electrocorticographic signals were recorded from the exposed cortex as the patient participated in a 3-min screening task involving active (patient naming visually presented words) and rest (patient silent) conditions. A spectral comparison of the 2 conditions revealed specific cortical locations associated with activation during speech. The patient was then widely mapped using ECS. Three of 4 sites identified by ECS were also identified passively and in parallel by EFAM, 2 with statistical significance and the third by qualitative inspection. Conclusion EFAM was technically achieved in an awake craniotomy patient and had good concordance with ECS mapping. Because it poses no risk of afterdischarges and offers substantial time savings, EFAM holds promise for future development as an adjunct intraoperative mapping tool. Additionally, the cortical signals obtained by this modality can be utilized for localization in the presence of a tumor adjacent to the eloquent regions. PMID:19940544

  10. Frequencies and trends of significant characteristics of reported events in Germany

    International Nuclear Information System (INIS)

    Farber, G.; Matthes, H.

    2001-01-01

    In the frame of its support to the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety the GRS continuously performs in-depth technical analyses of reported events at operating nuclear power reactors in Germany which can be used for the determination of plant weaknesses with regard to reactor safety. During the last 18 months, in addition to those activities, the GRS has developed a data bank model for the statistical assessment of events. This model is based on a hierarchically structured, detailed coding system with respect to technical and safety relevant characteristics of the plants and the systematic characterization of plant-specific events. The data bank model is ready for practical application. Results of a first statistical evaluation, taking into account the data sets from the time period 1996 to 1999, are meanwhile available. By increasing the amount of data it will become possible to herewith improve the statements concerning trends of safety aspects. This report describes the coding system, the evaluation model, the data input and the evaluations performed during the period beginning in April 2000. (authors)

  11. Frequencies and trends of significant characteristics of reported events in Germany

    Energy Technology Data Exchange (ETDEWEB)

    Farber, G.; Matthes, H. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Koln (Germany)

    2001-07-01

    In the frame of its support to the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety the GRS continuously performs in-depth technical analyses of reported events at operating nuclear power reactors in Germany which can be used for the determination of plant weaknesses with regard to reactor safety. During the last 18 months, in addition to those activities, the GRS has developed a data bank model for the statistical assessment of events. This model is based on a hierarchically structured, detailed coding system with respect to technical and safety relevant characteristics of the plants and the systematic characterization of plant-specific events. The data bank model is ready for practical application. Results of a first statistical evaluation, taking into account the data sets from the time period 1996 to 1999, are meanwhile available. By increasing the amount of data it will become possible to herewith improve the statements concerning trends of safety aspects. This report describes the coding system, the evaluation model, the data input and the evaluations performed during the period beginning in April 2000. (authors)

  12. Dynamic and structural characterisation of micellar solutions of surfactants by spin relaxation and translational diffusion

    International Nuclear Information System (INIS)

    Mahieu, Nathalie

    1992-01-01

    The work reported in this research thesis aimed at characterizing micellar phases formed by some surfactants (sodium carboxylates) in aqueous solution. After some recalls on nuclear magnetic resonance dealing with spin relaxation (longitudinal relaxation, transverse relaxation, relaxation in the rotating coordinate system, and crossed relaxation), and comments on the dipolar mechanism responsible of relaxation phenomena, the author presents the methods used for relaxation parameter measurement and the data processing software issued from experiments. He presents experiments which allowed the self-diffusion coefficient to be measured, reports data processing, and addresses problems of special diffusion and of coherence transfers during diffusion measurements. Results of proton relaxation measurements are then presented and discussed. They are used to determine the micellar state of the studied carboxylates. The case of the oleate is also addressed. Measurements of carbon-13 relaxation times are reported, and exploited in terms of structural parameters by using the Relaxator software. An original method of the hetero-nuclear Overhauser method is presented, and used to assess the average distance between water molecules and micelle surface [fr

  13. Identification of low frequency anti-erythrocyte antibodies in chronically transfused patient with beta-thalassemia: a case report

    Directory of Open Access Journals (Sweden)

    Ana Rúbia Magalhães Ferreira

    2015-02-01

    Full Text Available The rate of erythrocyte alloimmunization in tranfusion-dependent patients can reach 50%, although the frequency of clinically relevant antibodies in transfused patients is not fully known, it is estimated that about 1% of patients are sensitized to each unit of transfused RBCs. The aim of this study is to report the case of  an 11-year-old girl with ?-thalassemia major, chronically transfused, which was detected in pre-transfusion protocol, the presence of two rare anti-erythrocyte antibodies: anti-Colton b (anti-Cob and anti-Lutheran 14 (anti-Lu14. To survey the clinical and laboratory patient history, research records filed in the archives of the university hospital in which the patient is monitored system was performed. The phenotyping erythrocyte in multitransfused patients is essential to decrease the risk of complications due to alloimmunization and estimate the availability of compatible blood. Thus, the report of this case may contribute to increase knowledge about of the real frequency of uncommon anti-erythrocyte antibodies in thalassemic patients.

  14. Analysis of rail accident frequencies and severities for the assessment of radioactive material transport risk - Summary report

    International Nuclear Information System (INIS)

    Heywood, J.D.; Schwartz, G.; Fett, J.

    2001-01-01

    This shortened version of the final contractual report to the European Commission DGXVII summarises the work performed and the conclusions drawn from consideration, comparison and analysis of transport accident frequency and severity assessment methods for radioactive material transport by rail. This paper aims to provide an introduction to the study whose final report is 155 pages in length. The findings are based on a comprehensive review of transport risk assessment methods and related databases available to EU member states. The emphasis has been on the probabilistic accident severity and frequency assessment methodologies developed and used by the organisations involved in this EU-funded research project - AEA Technology and GRS. The results should be of major assistance in the understanding and development of standardised quantitative risk assessment models. Further work is suggested to underpin the development of a harmonised accident methodology including the collection of more detailed rail data and analysis on a year by year basis as well as further consideration of the assumptions made for fire accident scenarios. (author)

  15. Relaxation properties in classical diamagnetism

    Science.gov (United States)

    Carati, A.; Benfenati, F.; Galgani, L.

    2011-06-01

    It is an old result of Bohr that, according to classical statistical mechanics, at equilibrium a system of electrons in a static magnetic field presents no magnetization. Thus a magnetization can occur only in an out of equilibrium state, such as that produced through the Foucault currents when a magnetic field is switched on. It was suggested by Bohr that, after the establishment of such a nonequilibrium state, the system of electrons would quickly relax back to equilibrium. In the present paper, we study numerically the relaxation to equilibrium in a modified Bohr model, which is mathematically equivalent to a billiard with obstacles, immersed in a magnetic field that is adiabatically switched on. We show that it is not guaranteed that equilibrium is attained within the typical time scales of microscopic dynamics. Depending on the values of the parameters, one has a relaxation either to equilibrium or to a diamagnetic (presumably metastable) state. The analogy with the relaxation properties in the Fermi Pasta Ulam problem is also pointed out.

  16. Onsager relaxation of toroidal plasmas

    International Nuclear Information System (INIS)

    Samain, A.; Nguyen, F.

    1997-01-01

    The slow relaxation of isolated toroidal plasmas towards their thermodynamical equilibrium is studied in an Onsager framework based on the entropy metric. The basic tool is a variational principle, equivalent to the kinetic equation, involving the profiles of density, temperature, electric potential, electric current. New minimization procedures are proposed to obtain entropy and entropy production rate functionals. (author)

  17. Anisotropic spin relaxation in graphene

    NARCIS (Netherlands)

    Tombros, N.; Tanabe, S.; Veligura, A.; Jozsa, C.; Popinciuc, M.; Jonkman, H. T.; van Wees, B. J.

    2008-01-01

    Spin relaxation in graphene is investigated in electrical graphene spin valve devices in the nonlocal geometry. Ferromagnetic electrodes with in-plane magnetizations inject spins parallel to the graphene layer. They are subject to Hanle spin precession under a magnetic field B applied perpendicular

  18. Stochastic and Chaotic Relaxation Oscillations

    NARCIS (Netherlands)

    Grasman, J.; Roerdink, J.B.T.M.

    1988-01-01

    For relaxation oscillators stochastic and chaotic dynamics are investigated. The effect of random perturbations upon the period is computed. For an extended system with additional state variables chaotic behavior can be expected. As an example, the Van der Pol oscillator is changed into a

  19. Tensions relaxation in Zircaloy-4

    International Nuclear Information System (INIS)

    Cuniberti, A.M.; Picasso, A.C.

    1990-01-01

    Traction and stress relaxation studies were performed on polycrystalline Zry-4 at room temperature. The effect of loading velocity on the plastic behaviour of the material is discussed, analysing log σ vs. log dε/dt at different deformation levels. The contribution introduced by the testing machine was taken into account in data evaluation. (Author). 7 refs., 3 figs., 3 tabs

  20. Nuclear magnetic relaxation of methyl group in liquids

    International Nuclear Information System (INIS)

    Blicharska, B.

    1986-01-01

    The theoretical description of the relaxation process of methyl group in liquids and some results of the measurements of relaxation function and relaxation times for cryoprotective solutions are presented. Starting from the application of the operator formalism the general equation for spin operators e.g. components of the nuclear spin and magnetization is founded. Next, the spin Hamiltonian is presented as contraction of the symmetry adapted spherical tensors as well as the correlation functions and spectral densities. On the basis of extended and modified Woessner model of motion the correlation functions and spectral densities are calculated for methyl group in liquids. Using these functions the relaxation matrix elements, the spin-spin and spin-lattice relaxation times can be expressed. The prediction of the theory agrees with author's previous experiments on cryoprotective solutions. The observed dependence on temperature, frequency and isotopic dilution in methanol-water, methanol-dimethyl sulfoxide (DMSO) and DMSO-water solutions is in a satisfactory agreement with theoretical equations. 34 refs. (author)

  1. Scalar Similarity for Relaxed Eddy Accumulation Methods

    Science.gov (United States)

    Ruppert, Johannes; Thomas, Christoph; Foken, Thomas

    2006-07-01

    The relaxed eddy accumulation (REA) method allows the measurement of trace gas fluxes when no fast sensors are available for eddy covariance measurements. The flux parameterisation used in REA is based on the assumption of scalar similarity, i.e., similarity of the turbulent exchange of two scalar quantities. In this study changes in scalar similarity between carbon dioxide, sonic temperature and water vapour were assessed using scalar correlation coefficients and spectral analysis. The influence on REA measurements was assessed by simulation. The evaluation is based on observations over grassland, irrigated cotton plantation and spruce forest. Scalar similarity between carbon dioxide, sonic temperature and water vapour showed a distinct diurnal pattern and change within the day. Poor scalar similarity was found to be linked to dissimilarities in the energy contained in the low frequency part of the turbulent spectra ( definition.

  2. Treatment of Nightmares via Relaxation and Desensitization: A Controlled Evaluation.

    Science.gov (United States)

    Miller, William R.; DiPilato, Marina

    1983-01-01

    Investigated the role of relaxation training as a component of desensitization to nightmares in adults (N=32). Results showed an 80 percent reduction in nightmares reported by 20 clients, of whom 12 reported total elimination of symptoms at 25-week follow-up, suggesting the effectiveness of a behavioral approach in treating nightmares. (LLL)

  3. Sleep, Stress & Relaxation: Rejuvenate Body & Mind

    Science.gov (United States)

    Sleep, Stress & Relaxation: Rejuvenate Body & Mind; Relieve Stress; best ways to relieve stress; best way to relieve stress; different ways to relieve stress; does smoking relieve stress; does tobacco relieve stress; how can I relieve stress; how can you relieve stress; how do I relieve stress; reduce stress; does smoking reduce stress; how can I reduce stress; how to reduce stress; reduce stress; reduce stress levels; reducing stress; smoking reduce stress; smoking reduces stress; stress reducing techniques; techniques to reduce stress; stress relief; best stress relief; natural stress relief; need stress relief; relief for stress; relief from stress; relief of stress; smoking and stress relief; smoking for stress relief; smoking stress relief; deal with stress; dealing with stress; dealing with anger; dealing with stress; different ways of dealing with stress; help dealing with stress; how to deal with anger; how to deal with stress; how to deal with stress when quitting smoking; stress management; free stress management; how can you manage stress; how do you manage stress; how to manage stress; manage stress; management of stress; management stress; managing stress; strategies for managing stress; coping with stress; cope with stress; copeing with stress; coping and stress; coping skills for stress; coping strategies for stress; coping strategies with stress; coping strategy for stress; coping with stress; coping with stress and anxiety; emotional health; emotional health; emotional health article; emotional health articles; deep relaxation; deep breathing relaxation techniques; deep muscle relaxation; deep relaxation; deep relaxation meditation; deep relaxation technique; deep relaxation techniques; meditation exercises; mindful exercises; mindful meditation exercises; online relaxation exercises; relaxation breathing exercises; relaxation exercise; relaxation exercises; stress relaxation; methods of relaxation for stress; relax stress; relax techniques stress

  4. Correlation of carrier localization with relaxation time distribution and electrical conductivity relaxation in silver-nanoparticle-embedded moderately doped polypyrrole nanostructures

    Science.gov (United States)

    Biswas, Swarup; Dutta, Bula; Bhattacharya, Subhratanu

    2014-02-01

    The electrical conductivity relaxation in moderately doped polypyrrole and its nanocomposites reinforced with different proportion of silver nanoparticles was investigated in both frequency and time domain. An analytical distribution function of relaxation times is constructed from the results obtained in the frequency domain formalism and is used to evaluate the Kohlrausch-Williams-Watts (KWW) type decay function in the time domain. The thermal evolution of different relaxation parameters was analyzed. The temperature-dependent dc electrical conductivity, estimated from the average conductivity relaxation time is observed to depend strongly on the nanoparticle loading and follows Mott three-dimensional variable range hopping (VRH) conduction mechanism. The extent of charge carrier localization calculated from the VRH mechanism is well correlated to the evidences obtained from the structural characterizations of different nanostructured samples.

  5. Enhanced AC conductivity and dielectric relaxation properties of polypyrrole nanoparticles irradiated with Ni{sup 12+} swift heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Hazarika, J.; Kumar, A., E-mail: ask@tezu.ernet.in

    2014-08-15

    In this paper, we report the 160 MeV Ni{sup 12+} swift heavy ions (SHIs) irradiation effects on AC conductivity and dielectric relaxation properties of polypyrrole (PPy) nanoparticles in the frequency range of 42 Hz–5 MHz. Four ion fluences of 5 × 10{sup 10}, 1 × 10{sup 11}, 5 × 10{sup 11} and 1 × 10{sup 12} ions/cm{sup 2} have been used for the irradiation purpose. Transport properties in the pristine and irradiated PPy nanoparticles have been investigated with permittivity and modulus formalisms to study the polarization effects and conductivity relaxation. With increasing ion fluence, the relaxation peak in imaginary modulus (M{sup ″}) plots shifts toward high frequency suggesting long range motion of the charge carriers. The AC conductivity studies suggest correlated barrier hopping as the dominant transport mechanism. The hopping distance (R{sub ω}) of the charge carriers decreases with increasing the ion fluence. Binding energy (W{sub m}) calculations depict that polarons are the dominant charge carriers.

  6. Mechanisms of relaxation and spin decoherence in nanomagnets

    Science.gov (United States)

    van Tol, Johan

    Relaxation in spin systems is of great interest with respect to various possible applications like quantum information processing and storage, spintronics, and dynamic nuclear polarization (DNP). The implementation of high frequencies and fields is crucial in the study of systems with large zero-field splitting or large interactions, as for example molecular magnets and low dimensional magnetic materials. Here we will focus on the implementation of pulsed Electron Paramagnetic Resonance (ERP) at multiple frequencies of 10, 95, 120, 240, and 336 GHz, and the relaxation and decoherence processes as a function of magnetic field and temperature. Firstly, at higher frequencies the direct single-phonon spin-lattice relaxation (SLR) is considerably enhanced, and will more often than not be the dominant relaxation mechanism at low temperatures, and can be much faster than at lower fields and frequencies. In principle the measurement of the SLR rates as a function of the frequency provides a means to map the phonon density of states. Secondly, the high electron spin polarization at high fields has a strong influence on the spin fluctuations in relatively concentrated spin systems, and the contribution of the electron-electron dipolar interactions to the coherence rate can be partially quenched at low temperatures. This not only allows the study of relatively concentrated spin systems by pulsed EPR (as for example magnetic nanoparticles and molecular magnets), it enables the separation of the contribution of the fluctuations of the electron spin system from other decoherence mechanisms. Besides choice of temperature and field, several strategies in sample design, pulse sequences, or clock transitions can be employed to extend the coherence time in nanomagnets. A review will be given of the decoherence mechanisms with an attempt at a quantitative comparison of experimental rates with theory.

  7. Magnon interaction and relaxation in yttrium iron garnet

    International Nuclear Information System (INIS)

    Mukimov, K.M.; Jumaev, M.R.; Kenjaev, Z.M.

    2007-01-01

    Full text: Magnon interaction and relaxation are the fundamental characteristics describing the response of any system to an external AC field. Almost all experiments aimed at magnon excitation have been carried out in the microwave frequency range where only magnons with energies 0.1 - 5 K can be excited. Nevertheless, all magnons with energy lower or order of the temperature are involved in the processes of low energy magnon relaxation. The present study deals with the interactions of magnons in YIG in thermodynamic equilibrium at temperatures up to 300 K. We consider the exchange and magnetic - dipole terms in the YIG Hamiltonian and a term due to the local uniaxial crystallographic anisotropy, find the corresponding amplitudes of three - and four - magnon process, and calculate the relaxation rate and the correction to the ferromagnon frequency to the first order in the interaction. This correction is positive, in contrast to the case of ferromagnets, and it is proportional to at temperatures up to, in agreement with experiment. The exchange - relaxation rate of the magnons is found as a function of the wave vector and temperature. In the region this rate agrees with the familiar expression for ferromagnets. At higher temperatures, at which the main contribution to the exchange damping is from the magnons of the linear part of the spectrum, the temperature dependence of the damping becomes stronger. (authors)

  8. Dielectric relaxation in Li2SO4 in the intermedia-temperature regime

    Science.gov (United States)

    Diosa, J. E.; Vargas, R. A.; Fernández, M. E.; Albinsson, I.; Mellander, B.-E.

    2005-08-01

    The dielectric permittivity of polycrystalline Li2SO4 was measured from 5 Hz to 13 MHz and over the temperature range 235-460 °C. The corrected imaginary part of permittivity, , and its real part vs. frequency clearly show a new dielectric relaxation around fmax = 2 × 104 Hz at T = 256 °C, which shifts to higher frequencies (1 MHz) as the temperatures increases. The relaxation frequency (calculated from the peak position of ) vs. reciprocal T shows an activated relaxation process with activation energy Ea= 0.9 eV, which is very close to that derived from the dc conductivity, E (0.87 eV). We suggest that this dielectric relaxation could be due to the Li+ jump and SO4- reorientation that cause distortion and change of the local lattice polarizability inducing dipoles like LiSO4-.

  9. Appropriateness of Taped versus Live Relaxation in the Systematic Desensitization of Anticipatory Nausea and Vomiting in Cancer Patients.

    Science.gov (United States)

    Morrow, Gary R.

    1984-01-01

    Investigated whether the relaxation part of systematic desensitization could be learned by cancer patients from a prerecorded audiotape. Results showed four of five patients assigned to a taped-relaxation group experienced nausea while listening to the audiotape, whereas none of five patients taught muscle relaxation in person reported nausea. (BH)

  10. Nuclear magnetic relaxation in aqueous praseodymium and europium solutions

    International Nuclear Information System (INIS)

    Lopez, J.L.; Diaz, D.

    1991-01-01

    A general theory for the relaxation of the nuclear spin in paramagnetic complexes where the electronic spin is within a slow-movement regime was presented by Benetis et al. and applied to d-group elements (Ni 2+ , Co 2+ ). This paper show the possibility to apply such formalism to f-group elements and it was developed for S=3(Eu 3+ ). A group of magnitudes characterizing the microstructure and dynamics of these solutions is reported with the approximations used. The dispersion of the nuclear magnetic relaxation (NMRD) for the proton of the variable field was also assessed which had a similar behaviour to what was experimentally reported

  11. Dielectric dispersion, relaxation dynamics and thermodynamic studies of Beta-Alanine in aqueous solutions using picoseconds time domain reflectometry

    Science.gov (United States)

    Vinoth, K.; Ganesh, T.; Senthilkumar, P.; Sylvester, M. Maria; Karunakaran, D. J. S. Anand; Hudge, Praveen; Kumbharkhane, A. C.

    2017-09-01

    The aqueous solution of beta-alanine characterised and studied by their dispersive dielectric properties and relaxation process in the frequency domain of 10×106 Hz to 30×109 Hz with varying concentration in mole fractions and temperatures. The molecular interaction and dielectric parameters are discussed in terms of counter-ion concentration theory. The static permittivity (ε0), high frequency dielectric permittivity (ε∞) and excess dielectric parameters are accomplished by frequency depended physical properties and relaxation time (τ). Molecular orientation, ordering and correlation factors are reported as confirmation of intermolecular interactions. Ionic conductivity and thermo dynamical properties are concluded with the behaviour of the mixture constituents. Solute-solvent, solute-solute interaction, structure making and breaking abilities of the solute in aqueous medium are interpreted. Fourier Transform Infrared (FTIR) spectra of beta- alanine single crystal and liquid state have been studied. The 13C Nuclear Magnetic Resonance (NMR) spectral studies give the signature for resonating frequencies and chemical shifts of beta-alanine.

  12. Relaxation Techniques to Manage IBS Symptoms

    Science.gov (United States)

    ... for 15–20 seconds and then begin again. Progressive Muscle Relaxation This method of relaxation focuses on ... helpful, please consider supporting IFFGD with a small tax- deductible donation. Make Donation Adapted from IFFGD Publication # ...

  13. Relaxation and Distraction in Experimental Desensitization.

    Science.gov (United States)

    Weir, R. O.; Marshall, W. L.

    1980-01-01

    Compared experimental desensitization with a procedure that replaced relaxation with a distraction task and with an approach that combined both relaxation and distraction. Desensitization generally was more effective than the other two procedures. (Author)

  14. Relaxation as a Factor in Semantic Desensitization

    Science.gov (United States)

    Bechtel, James E.; McNamara, J. Regis

    1975-01-01

    Relaxation and semantic desensitization were used to alleviate the fear of phobic females. Results showed that semantic desensitization, alone or in combination with relaxation, failed to modify the evaluative meanings evoked by the feared object. (SE)

  15. [Leaking: Frequency and correlates of announcements and threats of homicidal violence reported by Berlin schools between 1996 and 2007].

    Science.gov (United States)

    Leuschner, Vincenz; Bondü, Rebecca; Allroggen, Marc; Scheithauer, Herbert

    2016-01-01

    Threats and announcements of homicidal violence at schools may have massive consequences like evacuations, police searches, criminal investigations, or loss of the sense of security by students, teachers, and parents. However, there is a lack of systematic studies about that phenomenon. The present article would like to contribute to closing the research gap. It presents results about the frequency and structure of threats and announcements of homicidal violence in schools in Berlin. The study is based on an official dataset from school administration reports of violent acts in Berlin schools which has been studied within the Berlin Leaking-Projekt. The sample consists of 427 threats and announcements of homicidal violence between 1996 and 2007. The study is an exceptional analysis of the phenomenon: it presents crosscutting results about frequency and characteristics of threats and the threatening students as well as results of a longitudinal analysis about the development of threats and announcements. Results show a rate of 0,3 threats and announcements per 1 000 student and year. During the observation time span a steady increase of threats and announcements – year by year, influenced by imitation effects after school shootings – has been observed.

  16. Nonadiabatic exchange dynamics during adiabatic frequency sweeps.

    Science.gov (United States)

    Barbara, Thomas M

    2016-04-01

    A Bloch equation analysis that includes relaxation and exchange effects during an adiabatic frequency swept pulse is presented. For a large class of sweeps, relaxation can be incorporated using simple first order perturbation theory. For anisochronous exchange, new expressions are derived for exchange augmented rotating frame relaxation. For isochronous exchange between sites with distinct relaxation rate constants outside the extreme narrowing limit, simple criteria for adiabatic exchange are derived and demonstrate that frequency sweeps commonly in use may not be adiabatic with regard to exchange unless the exchange rates are much larger than the relaxation rates. Otherwise, accurate assessment of the sensitivity to exchange dynamics will require numerical integration of the rate equations. Examples of this situation are given for experimentally relevant parameters believed to hold for in-vivo tissue. These results are of significance in the study of exchange induced contrast in magnetic resonance imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. On relaxation mechanism of tangensial losses in soils

    International Nuclear Information System (INIS)

    Babayev, M.P.; Gerayzade, A.P.; Mamedov, N.A.

    2009-01-01

    By experimentally at high-frequency bridge method on dependence of a tangent of a corner of dielectric losses of soil fom humidity and frequency of an electromagnetic field are investigated. In air-dry samples of soils the size of the most probable time of a relaxation and its maximum is established. It is shown that in the field of gravitational humidity, in the soil sample, at a maximum of a tangent of a corner of dielectric losses through conductivity will be veiled, i.e. obviously is not shown. As a result of the received data it is established that in the field of the adsorbed soil moisture the spectrum of time of relaxation is characterized by the wide strip reflecting heterogeneity of its dielectric properties. All this is offered to be used at designing of delkometric hydrometers and measurement of soil humidity

  18. Aging of the Johari-Goldstein relaxation in the glass-forming liquids sorbitol and xylitol

    Science.gov (United States)

    Yardimci, Hasan; Leheny, Robert L.

    2006-06-01

    Employing frequency-dependent dielectric susceptibility we characterize the aging in two supercooled liquids, sorbitol and xylitol, below their calorimetric glass transition temperatures. In addition to the alpha relaxation that tracks the structural dynamics, the susceptibility of both liquids possesses a secondary Johari-Goldstein relaxation at higher frequencies. Following a quench through the glass transition, the susceptibility slowly approaches the equilibrium behavior. For both liquids, the magnitude of the Johari-Goldstein relaxation displays a dependence on the time since the quench, or aging time, that is quantitatively very similar to the age dependence of the alpha peak frequency. The Johari-Goldstein relaxation time remains constant during aging for sorbitol while it decreases slightly with age for xylitol. Hence, one cannot sensibly assign a fictive temperature to the Johari-Goldstein relaxation. This behavior contrasts with that of liquids lacking distinct Johari-Goldstein peaks for which the excess wing of the alpha peak tracks the main part of the peak during aging, enabling the assignment of a single fictive temperature to the entire spectrum. The aging behavior of the Johari-Goldstein relaxation time further calls into question the possibility that the relaxation time possesses stronger temperature dependence in equilibrium than is observed in the out-of-equilibrium state below the glass transition.

  19. Plasmon-mediated energy relaxation in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, D. K. [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287-5706 (United States); Somphonsane, R. [Department of Physics, King Mongkut' s Institute of Technology, Ladkrabang, Bangkok 10520 (Thailand); Ramamoorthy, H.; Bird, J. P. [Department of Electrical Engineering, University at Buffalo, the State University of New York, Buffalo, New York 14260-1500 (United States)

    2015-12-28

    Energy relaxation of hot carriers in graphene is studied at low temperatures, where the loss rate may differ significantly from that predicted for electron-phonon interactions. We show here that plasmons, important in the relaxation of energetic carriers in bulk semiconductors, can also provide a pathway for energy relaxation in transport experiments in graphene. We obtain a total loss rate to plasmons that results in energy relaxation times whose dependence on temperature and density closely matches that found experimentally.

  20. Participant characteristics associated with errors in self-reported energy intake from the Women's Health Initiative food-frequency questionnaire.

    Science.gov (United States)

    Horner, Neilann K; Patterson, Ruth E; Neuhouser, Marian L; Lampe, Johanna W; Beresford, Shirley A; Prentice, Ross L

    2002-10-01

    Errors in self-reported dietary intake threaten inferences from studies relying on instruments such as food-frequency questionnaires (FFQs), food records, and food recalls. The objective was to quantify the magnitude, direction, and predictors of errors associated with energy intakes estimated from the Women's Health Initiative FFQ. Postmenopausal women (n = 102) provided data on sociodemographic and psychosocial characteristics that relate to errors in self-reported energy intake. Energy intake was objectively estimated as total energy expenditure, physical activity expenditure, and the thermic effect of food (10% addition to other components of total energy expenditure). Participants underreported energy intake on the FFQ by 20.8%; this error trended upward with younger age (P = 0.07) and social desirability (P = 0.09) but was not associated with body mass index (P = 0.95). The correlation coefficient between reported energy intake and total energy expenditure was 0.24; correlations were higher among women with less education, higher body mass index, and greater fat-free mass, social desirability, and dissatisfaction with perceived body size (all P diet and disease association studies.

  1. Physiological blunting during pregnancy extends to induced relaxation.

    Science.gov (United States)

    DiPietro, Janet A; Mendelson, Tamar; Williams, Erica L; Costigan, Kathleen A

    2012-01-01

    There is accumulating evidence that pregnancy is accompanied by hyporesponsivity to physical, cognitive, and psychological challenges. This study evaluates whether observed autonomic blunting extends to conditions designed to decrease arousal. Physiological and psychological responsivity to an 18-min guided imagery relaxation protocol in healthy pregnant women during the 32nd week of gestation (n=54) and non-pregnant women (n=28) was measured. Data collection included heart period (HP), respiratory sinus arrhythmia (RSA), tonic and phasic measures of skin conductance (SCL and NS-SCR), respiratory period (RP), and self-reported psychological relaxation. As expected, responses to the manipulation included increased HP, RSA, and RP and decreased SCL and NS-SCR, followed by post-manipulation recovery. However, responsivity was attenuated for all physiological measures except RP in pregnant women, despite no difference in self-reported psychological relaxation. Findings support non-specific blunting of physiological responsivity during pregnancy. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Nonlinear Relaxation in Population Dynamics

    Science.gov (United States)

    Cirone, Markus A.; de Pasquale, Ferdinando; Spagnolo, Bernardo

    We analyze the nonlinear relaxation of a complex ecosystem composed of many interacting species. The ecological system is described by generalized Lotka-Volterra equations with a multiplicative noise. The transient dynamics is studied in the framework of the mean field theory and with random interaction between the species. We focus on the statistical properties of the asymptotic behaviour of the time integral of the ith population and on the distribution of the population and of the local field.

  3. Structural relaxation: low temperature properties

    International Nuclear Information System (INIS)

    Cruz, F. de la

    1984-01-01

    We discuss the changes in transport and superconducting properties of amorphous Zr 70 Cu 30 , induced by thermal relaxation. The experimental results are used to investigate the relation between the microscopic parameters and the observed physical properties. It is shown that the density of eletronic states determines the shift Tc as well as the variation of the electrical resistivity. It is necessary to assume strong hybridization between s and d bands to understand the eletrodynamic response of the superconductor. (Author) [pt

  4. The Effects of Suggestibility on Relaxation.

    Science.gov (United States)

    Rickard, Henry C.; And Others

    1985-01-01

    Selected undergraduates (N=32) on the basis of Creative Imagination Scale scores and randomly assigned high and low suggestibility subjects to progressive relaxation (PR) and suggestions of relaxation (SR) training modes. Results revealed a significant pre-post relaxation effect, and main efffects for both suggestibility and training mode. (NRB)

  5. Relaxed Poisson cure rate models.

    Science.gov (United States)

    Rodrigues, Josemar; Cordeiro, Gauss M; Cancho, Vicente G; Balakrishnan, N

    2016-03-01

    The purpose of this article is to make the standard promotion cure rate model (Yakovlev and Tsodikov, ) more flexible by assuming that the number of lesions or altered cells after a treatment follows a fractional Poisson distribution (Laskin, ). It is proved that the well-known Mittag-Leffler relaxation function (Berberan-Santos, ) is a simple way to obtain a new cure rate model that is a compromise between the promotion and geometric cure rate models allowing for superdispersion. So, the relaxed cure rate model developed here can be considered as a natural and less restrictive extension of the popular Poisson cure rate model at the cost of an additional parameter, but a competitor to negative-binomial cure rate models (Rodrigues et al., ). Some mathematical properties of a proper relaxed Poisson density are explored. A simulation study and an illustration of the proposed cure rate model from the Bayesian point of view are finally presented. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Arresting relaxation in Pickering Emulsions

    Science.gov (United States)

    Atherton, Tim; Burke, Chris

    2015-03-01

    Pickering emulsions consist of droplets of one fluid dispersed in a host fluid and stabilized by colloidal particles absorbed at the fluid-fluid interface. Everyday materials such as crude oil and food products like salad dressing are examples of these materials. Particles can stabilize non spherical droplet shapes in these emulsions through the following sequence: first, an isolated droplet is deformed, e.g. by an electric field, increasing the surface area above the equilibrium value; additional particles are then adsorbed to the interface reducing the surface tension. The droplet is then allowed to relax toward a sphere. If more particles were adsorbed than can be accommodated by the surface area of the spherical ground state, relaxation of the droplet is arrested at some non-spherical shape. Because the energetic cost of removing adsorbed colloids exceeds the interfacial driving force, these configurations can remain stable over long timescales. In this presentation, we present a computational study of the ordering present in anisotropic droplets produced through the mechanism of arrested relaxation and discuss the interplay between the geometry of the droplet, the dynamical process that produced it, and the structure of the defects observed.

  7. Relaxed plasma-vacuum systems

    International Nuclear Information System (INIS)

    Spies, G.O.; Lortz, D.; Kaiser, R.

    2001-01-01

    Taylor's theory of relaxed toroidal plasmas (states of lowest energy with fixed total magnetic helicity) is extended to include a vacuum between the plasma and the wall. In the extended variational problem, one prescribes, in addition to the helicity and the magnetic fluxes whose conservation follows from the perfect conductivity of the wall, the fluxes whose conservation follows from the assumption that the plasma-vacuum interface is also perfectly conducting (if the wall is a magnetic surface, then one has the toroidal and the poloidal flux in the vacuum). Vanishing of the first energy variation implies a pressureless free-boundary magnetohydrostatic equilibrium with a Beltrami magnetic field in the plasma, and in general with a surface current in the interface. Positivity of the second variation implies that the equilibrium is stable according to ideal magnetohydrodynamics, that it is a relaxed state according to Taylor's theory if the interface is replaced by a wall, and that the surface current is nonzero (at least if there are no closed magnetic field lines in the interface). The plane slab, with suitable boundary conditions to simulate a genuine torus, is investigated in detail. The relaxed state has the same double symmetry as the vessel if, and only if, the prescribed helicity is in an interval that depends on the prescribed fluxes. This interval is determined in the limit of a thin slab

  8. Regularized Label Relaxation Linear Regression.

    Science.gov (United States)

    Fang, Xiaozhao; Xu, Yong; Li, Xuelong; Lai, Zhihui; Wong, Wai Keung; Fang, Bingwu

    2018-04-01

    Linear regression (LR) and some of its variants have been widely used for classification problems. Most of these methods assume that during the learning phase, the training samples can be exactly transformed into a strict binary label matrix, which has too little freedom to fit the labels adequately. To address this problem, in this paper, we propose a novel regularized label relaxation LR method, which has the following notable characteristics. First, the proposed method relaxes the strict binary label matrix into a slack variable matrix by introducing a nonnegative label relaxation matrix into LR, which provides more freedom to fit the labels and simultaneously enlarges the margins between different classes as much as possible. Second, the proposed method constructs the class compactness graph based on manifold learning and uses it as the regularization item to avoid the problem of overfitting. The class compactness graph is used to ensure that the samples sharing the same labels can be kept close after they are transformed. Two different algorithms, which are, respectively, based on -norm and -norm loss functions are devised. These two algorithms have compact closed-form solutions in each iteration so that they are easily implemented. Extensive experiments show that these two algorithms outperform the state-of-the-art algorithms in terms of the classification accuracy and running time.

  9. Identification of structural relaxation in the dielectric response of water

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt; Kisliuk, Alexander; Solokov, Alexei P.

    2016-01-01

    One century ago pioneering dielectric results obtained for water and n-alcohols triggered the advent of molecular rotation diffusion theory considered by Debye to describe the primary dielectric absorption in these liquids. Comparing dielectric, viscoelastic, and light scattering results, we...... unambiguously demonstrate that the structural relaxation appears only as a high-frequency shoulder in the dielectric spectra of water. In contrast, the main dielectric peak is related to a supramolecular structure, analogous to the Debye-like peak observed in monoalcohols....

  10. Low-frequency magnetization processes in chemically etched Co-based amorphous ribbons

    International Nuclear Information System (INIS)

    Betancourt, I.; Martinez, L.A.; Valenzuela, R.

    2005-01-01

    In this report we present a study of the magnetization processes for Co-based amorphous ribbons at low frequencies (10 Hz-13 MHz) as a function of decreasing thicknesses attained by chemical etching. Reversible domain-wall bulging, characterized by initial permeability and relaxation frequency, was monitored by means of inductance measurements. The real part of inductance (proportional to initial permeability) exhibited a decreasing trend with diminishing ribbon thickness, together with an increasing tendency for the relaxation frequency. For high amplitude of the ac field (leading to domain-wall unpinning), reduced ribbon thickness showed a deleterious-enhancement effect on irreversible domain-wall displacement, which was observed for both real and imaginary inductance spectroscopic plots. Results are interpreted in terms of reduced domain-wall pinning distances resulting from thinner alloy samples

  11. Frequency and pattern of childhood symptom onset reported by first episode schizophrenia and clinical high risk youth.

    Science.gov (United States)

    Woodberry, Kristen A; Serur, Rachael A; Hallinan, Sean B; Mesholam-Gately, Raquelle I; Giuliano, Anthony J; Wojcik, Joanne D; Keshavan, Matcheri S; Frazier, Jean A; Goldstein, Jill M; Shenton, Martha E; McCarley, Robert W; Seidman, Larry J

    2014-09-01

    Psychosis prevention and early intervention efforts in schizophrenia have focused increasingly on sub-threshold psychotic symptoms in adolescents and young adults. Although many youth report symptom onset prior to adolescence, the childhood incidence of prodromal-level symptoms in those with schizophrenia or related psychoses is largely unknown. This study reports on the retrospective recall of prodromal-level symptoms from 40 participants in a first-episode of schizophrenia (FES) and 40 participants at "clinical high risk" (CHR) for psychosis. Onset of positive and non-specific symptoms was captured using the Structured Interview for Prodromal Syndromes. Frequencies are reported according to onset during childhood (prior to age 13), adolescence (13-17), or adulthood (18+). Childhood-onset of attenuated psychotic symptoms was not rare. At least 11% of FES and 23% of CHR reported specific recall of childhood-onset of unusual or delusional ideas, suspiciousness, or perceptual abnormalities. Most recalled experiencing non-specific symptoms prior to positive symptoms. CHR and FES did not differ significantly in the timing of positive and non-specific symptom onset. Other than being younger at assessment, those with childhood onset did not differ demographically from those with later onset. Childhood-onset of initial psychotic-like symptoms may be more common than previous research has suggested. Improved characterization of these symptoms and a focus on their predictive value for subsequent schizophrenia and other major psychoses are needed to facilitate screening of children presenting with attenuated psychotic symptoms. Accurate detection of prodromal symptoms in children might facilitate even earlier intervention and the potential to alter pre-illness trajectories. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. On the relation between quasi-static and dynamic stress induced reversible structural relaxation of amorphous alloys

    International Nuclear Information System (INIS)

    Krueger, P.; Stucky, T.; Boewe, M.; Neuhaeuser, H.

    1993-01-01

    Quasi-static stress relaxation and dynamic internal friction measurements of stress induced reversible structural relaxation were performed on the amorphous alloy Fe 40 Ni 40 B 20 . The kinetics can be well described by a stretched exponential Kohlrausch-Williams-Watts quasi-static relaxation. The thermally activated part of the internal friction shows an Arrhenius temperature behaviour for a fixed vibration frequency and an inverse power frequency behaviour for a fixed temperature. The activation energies calculated from the Arrhenius equation and from the frequency shift method are significantly different. In order to explain this discrepancy the relation between the quasi-static and the dynamic descriptions of the reversible relaxation is reexamined. In particular it is shown that these two activation energies are connected by the Kohlrausch exponent of the quasi-static relaxation. (orig.)

  13. Sandpile model for relaxation in complex systems

    International Nuclear Information System (INIS)

    Vazquez, A.; Sotolongo-Costa, O.; Brouers, F.

    1997-10-01

    The relaxation in complex systems is, in general, nonexponential. After an initial rapid decay the system relaxes slowly following a long time tail. In the present paper a sandpile moderation of the relaxation in complex systems is analysed. Complexity is introduced by a process of avalanches in the Bethe lattice and a feedback mechanism which leads to slower decay with increasing time. In this way, some features of relaxation in complex systems: long time tails relaxation, aging, and fractal distribution of characteristic times, are obtained by simple computer simulations. (author)

  14. Dielectric relaxation in Yb-doped SrZrO3

    International Nuclear Information System (INIS)

    Kamishima, O; Abe, Y; Ishii, T; Kawamura, J; Hattori, T

    2004-01-01

    The dielectric constant of the proton conductor SrZr 1-x Yb x O 3 (x 0-0.1) was measured as a function of temperature and frequency. Two well-defined relaxation peaks were observed in SrZrO 3 doped with more than 1 mol% of Yb. The assignment of the two dielectric relaxations is discussed in terms of IR spectra and by free energy calculation for a miscibility of dopant Yb ions. The Yb concentration dependence of the relaxation strength of the two dielectric relaxations is in agreement with the results calculated from the free energy. The two relaxations can be assigned to a reorientation of a single Yb-OH dipole and of Yb-OH dipoles associated with Yb-clusters. The attractive energy for Yb-clustering in SrZrO 3 is evaluated at about -85 meV

  15. Increased frequency and range of sexual behavior in a patient with Parkinson's disease after use of pramipexole: a case report.

    Science.gov (United States)

    Munhoz, Renato P; Fabiani, Giorgio; Becker, Nilson; Teive, Hélio A G

    2009-04-01

    Several recent reports have linked the use of dopamine agonists (DAs) to a variety of compulsive behaviors in patients with Parkinson's disease (PD). These inappropriate behaviors may include pathological gambling, compulsive shopping, and hypersexuality. To report the case of a patient with increased range of sexual behavior after use of pramipexole, a DA. A 67-year-old man with a 7-year diagnosis of PD treated with levodopa and pramipexole presented with a dramatic change in sexual behavior after an increase in DA dose. The patient, who historically was a very shy and conservative person, started to present increased frequency of sexual intercourse with his wife, during which he began speaking obscenities with an extreme preference for anal intercourse, preferences never requested before. After pramipexole was withdrawn, complete remission was observed with return to his usual sexual behavior. Hypersexuality and paraphilias are complications not uncommonly found in patients with PD under dopaminergic treatment. Further studies are needed for the understanding of this complex complication, and particularly the most prevalent relationship between pathological hypersexuality and use of DAs.

  16. The relationships between suggestibility, influenceability, and relaxability.

    Science.gov (United States)

    Polczyk, Romuald; Frey, Olga; Szpitalak, Malwina

    2013-01-01

    This research explores the relationships between relaxability and various aspects of suggestibility and influenceability. The Jacobson Progressive Muscle Relaxation procedure was used to induce relaxation. Tests of direct suggestibility, relating to the susceptibility of overt suggestions, and indirect suggestibility, referring to indirect hidden influence, as well as self-description questionnaires on suggestibility and the tendency to comply were used. Thayer's Activation-Deactivation Adjective Check List, measuring various kinds of activation and used as a pre- and posttest, determined the efficacy of the relaxation procedure. Indirect, direct, and self-measured suggestibility proved to be positively related to the ability to relax, measured by Thayer's subscales relating to emotions. Compliance was not related to relaxability. The results are discussed in terms of the aspects of relaxation training connected with suggestibility.

  17. Hydrogels with tunable stress relaxation regulate stem cell fate and activity

    Science.gov (United States)

    Chaudhuri, Ovijit; Gu, Luo; Klumpers, Darinka; Darnell, Max; Bencherif, Sidi A.; Weaver, James C.; Huebsch, Nathaniel; Lee, Hong-Pyo; Lippens, Evi; Duda, Georg N.; Mooney, David J.

    2016-03-01

    Natural extracellular matrices (ECMs) are viscoelastic and exhibit stress relaxation. However, hydrogels used as synthetic ECMs for three-dimensional (3D) culture are typically elastic. Here, we report a materials approach to tune the rate of stress relaxation of hydrogels for 3D culture, independently of the hydrogel's initial elastic modulus, degradation, and cell-adhesion-ligand density. We find that cell spreading, proliferation, and osteogenic differentiation of mesenchymal stem cells (MSCs) are all enhanced in cells cultured in gels with faster relaxation. Strikingly, MSCs form a mineralized, collagen-1-rich matrix similar to bone in rapidly relaxing hydrogels with an initial elastic modulus of 17 kPa. We also show that the effects of stress relaxation are mediated by adhesion-ligand binding, actomyosin contractility and mechanical clustering of adhesion ligands. Our findings highlight stress relaxation as a key characteristic of cell-ECM interactions and as an important design parameter of biomaterials for cell culture.

  18. Proton relaxation relationships of human and animal tissues in vitro. Changes due to autolysis and fixing

    International Nuclear Information System (INIS)

    Grodd, W.; Schmitt, W.G.H.

    1983-01-01

    The results of measurements of proton relaxation times of various tissues from rats, pigs and humans are reported; these were obtained by a resonance spectroscope at 20 MHz and 40 0 C. There were specific differences in both relaxation times (T 1 and T 2 ) of the liver and spleen. There was a difference of more than 150 ms in the longitudinal relaxation time between grey and white cerebral tissue. Autolytic changes show an increase in both relaxation times. Fixation produced a reduction in T 1 only. The significance of these findings for NMR tomography is discussed. (orig.) [de

  19. Suppression of Dyakonov-Perel Spin Relaxation in High-Mobility n-GaAs

    Science.gov (United States)

    Dzhioev, R. I.; Kavokin, K. V.; Korenev, V. L.; Lazarev, M. V.; Poletaev, N. K.; Zakharchenya, B. P.; Stinaff, E. A.; Gammon, D.; Bracker, A. S.; Ware, M. E.

    2004-11-01

    We report a large and unexpected suppression of the free electron spin-relaxation in lightly doped n-GaAs bulk crystals. The spin-relaxation rate shows a weak mobility dependence and saturates at a level 30 times less than that predicted by the Dyakonov-Perel theory. The dynamics of the spin-orbit field differs substantially from the usual scheme: although all the experimental data can be self-consistently interpreted as a precessional spin-relaxation induced by a random spin-orbit field, the correlation time of this random field, surprisingly, is much shorter than, and is independent of, the momentum relaxation time determined from transport measurements.

  20. Phase diagram and magnetic relaxation phenomena in Cu2OSeO3

    Science.gov (United States)

    Qian, F.; Wilhelm, H.; Aqeel, A.; Palstra, T. T. M.; Lefering, A. J. E.; Brück, E. H.; Pappas, C.

    2016-08-01

    We present an investigation of the magnetic-field-temperature phase diagram of Cu2OSeO3 based on dc magnetization and ac susceptibility measurements covering a broad frequency range of four orders of magnitude, from very low frequencies reaching 0.1 Hz up to 1 kHz. The experiments were performed in the vicinity of Tc=58.2 K and around the skyrmion lattice A phase. At the borders between the different phases the characteristic relaxation times reach several milliseconds and the relaxation is nonexponential. Consequently the borders between the different phases depend on the specific criteria and frequency used and an unambiguous determination is not possible.

  1. Quantifying protein dynamics in the ps–ns time regime by NMR relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, Griselda; LeMaster, David M., E-mail: david.lemaster@health.ny.gov [University at Albany - SUNY, Wadsworth Center, New York State Department of Health and Department of Biomedical Sciences, School of Public Health (United States)

    2016-11-15

    Both {sup 15}N chemical shift anisotropy (CSA) and sufficiently rapid exchange linebroadening transitions exhibit relaxation contributions that are proportional to the square of the magnetic field. Deconvoluting these contributions is further complicated by residue-dependent variations in protein amide {sup 15}N CSA values which have proven difficult to accurately measure. Exploiting recently reported improvements for the implementation of T{sub 1} and T{sub 1ρ} experiments, field strength-dependent studies have been carried out on the B3 domain of protein G (GB3) as well as on the immunophilin FKBP12 and a H87V variant of that protein in which the major conformational exchange linebroadening transition is suppressed. By applying a zero frequency spectral density rescaling analysis to the relaxation data collected at magnetic fields from 500 to 900 MHz {sup 1}H, differential residue-specific {sup 15}N CSA values have been obtained for GB3 which correlate with those derived from solid state and liquid crystalline NMR measurements to a level similar to the correlation among those previously reported studies. Application of this analysis protocol to FKBP12 demonstrated an efficient quantitation of both weak exchange linebroadening contributions and differential residue-specific {sup 15}N CSA values. Experimental access to such differential residue-specific {sup 15}N CSA values should significantly facilitate more accurate comparisons with molecular dynamics simulations of protein motion that occurs within the timeframe of global molecular tumbling.

  2. The relationship between interviewer-respondent race match and reporting of energy intake using food frequency questionnaires in the rural South United States

    Science.gov (United States)

    The purpose of the observational study was to determine whether interviewer race influences food frequency questionnaire (FFQ) reporting accuracy in a Deep South, largely African American cohort. A secondary analysis was conducted to investigate the influence of interviewer race on energy reporting ...

  3. Relaxation techniques for pain management in labour.

    Science.gov (United States)

    Smith, Caroline A; Levett, Kate M; Collins, Carmel T; Armour, Mike; Dahlen, Hannah G; Suganuma, Machiko

    2018-03-28

    Many women would like to avoid pharmacological or invasive methods of pain management in labour and this may contribute to the popularity of complementary methods of pain management. This review examined currently available evidence on the use of relaxation therapies for pain management in labour. This is an update of a review first published in 2011. To examine the effects of mind-body relaxation techniques for pain management in labour on maternal and neonatal well-being during and after labour. We searched Cochrane Pregnancy and Childbirth's Trials Register (9 May 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 5 2017), MEDLINE (1966 to 24 May 2017), CINAHL (1980 to 24 May 2017), the Australian New Zealand Clinical Trials Registry (18 May 2017), ClinicalTrials.gov (18 May 2017), the ISRCTN Register (18 May 2017), the WHO International Clinical Trials Registry Platform (ICTRP) (18 May 2017), and reference lists of retrieved studies. Randomised controlled trials (including quasi randomised and cluster trials) comparing relaxation methods with standard care, no treatment, other non-pharmacological forms of pain management in labour or placebo. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We attempted to contact study authors for additional information. We assessed evidence quality with GRADE methodology. This review update includes 19 studies (2519 women), 15 of which (1731 women) contribute data. Interventions examined included relaxation, yoga, music and mindfulness. Approximately half of the studies had a low risk of bias for random sequence generation and attrition bias. The majority of studies had a high risk of bias for performance and detection bias, and unclear risk of bias for, allocation concealment, reporting bias and other bias. We assessed the evidence from these studies as ranging from low to very low quality, and

  4. Measuring the equations of state in a relaxed magnetohydrodynamic plasma

    Science.gov (United States)

    Kaur, M.; Barbano, L. J.; Suen-Lewis, E. M.; Shrock, J. E.; Light, A. D.; Brown, M. R.; Schaffner, D. A.

    2018-01-01

    We report measurements of the equations of state of a fully relaxed magnetohydrodynamic (MHD) laboratory plasma. Parcels of magnetized plasma, called Taylor states, are formed in a coaxial magnetized plasma gun, and are allowed to relax and drift into a closed flux conserving volume. Density, ion temperature, and magnetic field are measured as a function of time as the Taylor states compress and heat. The theoretically predicted MHD and double adiabatic equations of state are compared to experimental measurements. We find that the MHD equation of state is inconsistent with our data.

  5. NMR relaxation dispersion of Miglyol molecules confined inside polymeric micro-capsules.

    Science.gov (United States)

    Nechifor, Ruben; Ardelean, Ioan; Mattea, Carlos; Stapf, Siegfried; Bogdan, Mircea

    2011-11-01

    Frequency dependent NMR relaxation studies have been carried out on Miglyol molecules confined inside core shell polymeric capsules to obtain a correlation between capsule dimension and the measurable parameters. The polymeric capsules were prepared using an interfacial polymerization technique for three different concentrations of Miglyol. It was shown that the variation of Miglyol concentration influences the capsule dimension. Their average size was estimated using the pulsed field gradient diffusometry technique. The relaxation dispersion curves were obtained at room temperature by a combined use of a fast field cycling instrument and a high-field instrument. The frequency dependence of relaxation rate shows a transition from a diffusion-limited to a surface-limited relaxation regime. Copyright © 2011 John Wiley & Sons, Ltd.

  6. Thermally induced magnetic relaxation in square artificial spin ice

    Science.gov (United States)

    Andersson, M. S.; Pappas, S. D.; Stopfel, H.; Östman, E.; Stein, A.; Nordblad, P.; Mathieu, R.; Hjörvarsson, B.; Kapaklis, V.

    2016-11-01

    The properties of natural and artificial assemblies of interacting elements, ranging from Quarks to Galaxies, are at the heart of Physics. The collective response and dynamics of such assemblies are dictated by the intrinsic dynamical properties of the building blocks, the nature of their interactions and topological constraints. Here we report on the relaxation dynamics of the magnetization of artificial assemblies of mesoscopic spins. In our model nano-magnetic system - square artificial spin ice - we are able to control the geometrical arrangement and interaction strength between the magnetically interacting building blocks by means of nano-lithography. Using time resolved magnetometry we show that the relaxation process can be described using the Kohlrausch law and that the extracted temperature dependent relaxation times of the assemblies follow the Vogel-Fulcher law. The results provide insight into the relaxation dynamics of mesoscopic nano-magnetic model systems, with adjustable energy and time scales, and demonstrates that these can serve as an ideal playground for the studies of collective dynamics and relaxations.

  7. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.

    2015-06-18

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s−1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m−2 h−1. The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m−2 h−1 while the biofilm thickness increased again after restoring the original flux of 20 L m−2 h−1, indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more

  8. Effects of relaxation on psychobiological wellbeing during pregnancy: a randomized controlled trial.

    Science.gov (United States)

    Urech, Corinne; Fink, Nadine S; Hoesli, Irène; Wilhelm, Frank H; Bitzer, Johannes; Alder, Judith

    2010-10-01

    Prenatal maternal stress is associated with adverse birth outcomes and may be reduced by relaxation exercises. The aim of the present study was to compare the immediate effects of two active and one passive 10-min relaxation technique on perceived and physiological indicators of relaxation. 39 healthy pregnant women recruited at the outpatient department of the University Women's Hospital Basel participated in a randomized controlled trial with an experimental repeated measure design. Participants were assigned to one of two active relaxation techniques, progressive muscle relaxation (PMR) or guided imagery (GI), or a passive relaxation control condition. Self-reported relaxation on a visual analogue scale (VAS) and state anxiety (STAI-S), endocrine parameters indicating hypothalamic-pituitary-adrenal (HPA) axis (cortisol and ACTH) and sympathetic-adrenal-medullary (SAM) system activity (norepinephrine and epinephrine), as well as cardiovascular responses (heart rate, systolic and diastolic blood pressure) were measured at four time points before and after the relaxation exercise. Between group differences showed, that compared to the PMR and control conditions, GI was significantly more effective in enhancing levels of relaxation and together with PMR, GI was associated with a significant decrease in heart rate. Within the groups, passive as well as active relaxation procedures were associated with a decline in endocrine measures except epinephrine. Taken together, these data indicate that different types of relaxation had differential effects on various psychological and biological stress systems. GI was especially effective in inducing self-reported relaxation in pregnant women while at the same time reducing cardiovascular activity. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Constancy and Change in the Prevalence and Frequency of Offending When Based on Longitudinal Self-reports or Official Records: Comparisons by Gender, Race, and Crime Type

    Science.gov (United States)

    Farrington, David P.; Hipwell, Alison E.; Stepp, Stephanie D.; Pardini, Dustin; Ahonen, Lia

    2015-01-01

    Introduction The study examines age-crime prevalence and age-crime frequency curves based on longitudinal data from boys in the Pittsburgh Youth Study and girls in the Pittsburgh Girls Study. Results Results show that the prevalence of the age-crime curve for theft and violence (based on self-reports or police charges) followed the typical age-crime curve for males and slightly less distinctly for females, with the peak of offending occurring earlier for self-reports than for police charges. The decrease in police charges for violence and theft took place at an earlier age for females than males, but this was not distinct when self-reported delinquency was the criterion. The mean frequency of self-reported theft and violence followed the age-crime curve for males but not for females, who showed a mean frequency of offending which was more constant. In contrast, the mean frequency of police charges increased with age for males and females. Comparing African-American and Caucasian males and females shows a higher prevalence but not a higher mean frequency of self-reported offending. Conclusions The results are reviewed in the light of other studies, and the policy implications of the findings are discussed. PMID:27610337

  10. Frequency and temperature dependence behaviour of impedance, modulus and conductivity of BaBi4Ti4O15 Aurivillius ceramic

    Directory of Open Access Journals (Sweden)

    Tanmaya Badapanda

    2014-09-01

    Full Text Available In this work, we report the dielectric, impedance, modulus and conductivity study of BaBi4Ti4O15 ceramic synthesized by solid state reaction. X-ray diffraction (XRD pattern showed orthorhombic structure with space group A21am confirming it to be an m = 4 member of the Aurivillius oxide. The frequency dependence dielectric study shows that the value of dielectric constant is high at lower frequencies and decreases with increase in frequency. Impedance spectroscopy analyses reveal a non-Debye relaxation phenomenon since relaxation frequency moves towards the positive side with increase in temperature. The shift in impedance peaks towards higher frequency side indicates conduction in material and favouring of the long rangemotion of mobile charge carriers. The Nyquist plot from complex impedance spectrum shows only one semicircular arc representing the grain effect in the electrical conduction. The modulus mechanism indicates the non-Debye type of conductivity relaxation in the material, which is supported by impedance data. Relaxation times extracted using imaginary part of complex impedance (Z′′ and modulus (M′′ were also found to follow Arrhenius law. The frequency dependent AC conductivity at different temperatures indicates that the conduction process is thermally activated. The variation of DC conductivity exhibits a negative temperature coefficient of resistance behaviour.

  11. Investigation of microwave transitions and nonlinear magneto-optical rotation in anti-relaxation-coated cells

    International Nuclear Information System (INIS)

    Budker, D.; Hollberg, L.; Kimball, D.F.; Kitching, J.; Pustclny, S.; Robinson, H.G.; Yashchuk, V.V.

    2004-01-01

    Using laser optical pumping, widths and frequency shifts are determined for microwave transitions between the components of the ground-state hyperfine structure for 85 Rb and 87 Rb atoms contained in vapor cells with alkane anti-relaxation coatings. The results are compared with data on Zeeman relaxation obtained in nonlinear magneto-optical rotation (NMOR) experiments, a comparison important for quantitative understanding of spin-relaxation mechanisms in coated cells. By comparing cells manufactured over a forty-year period we demonstrate the long-term stability of coated cells, which may be useful for atomic clocks and magnetometers

  12. Investigation of microwave transitions and nonlinear magneto-optical rotation in anti-relaxation-coated cells

    International Nuclear Information System (INIS)

    Budker, Dmitry; Hollberg, Leo; Kimball, Derek F.; Kitching, J.; Pustelny, Szymon; Yashchuk, Valeriy V.

    2004-01-01

    Using laser optical pumping, widths and frequency shifts are determined for microwave transitions between ground-state hyperfine components of 85 Rb and 87 Rb atoms contained in vapor cells with alkane anti-relaxation coatings. The results are compared with data on Zeeman relaxation obtained in nonlinear magneto-optical rotation (NMOR) experiments, a comparison important for quantitative understanding of spin-relaxation mechanisms in coated cells. By comparing cells manufactured over a forty-year period we demonstrate the long-term stability of coated cells, an important property for atomic clocks and magnetometers

  13. Dielectric relaxation study of the dynamics of monosaccharides: D-ribose and 2-deoxy-D-ribose

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, K; Kaminska, E; Wlodarczyk, P; Paluch, M; Ziolo, J [Institute of Physics, Silesian University, ulica Uniwersytecka 4, 40-007 Katowice (Poland); Ngai, K L [Naval Research Laboratory, Washington, DC 20375-5320 (United States)

    2008-08-20

    The dielectric loss spectra of two closely related monosaccharides, D-ribose and 2-deoxy-D-ribose, measured at ambient and elevated pressures are presented. 2-deoxy-D-ribose and D-ribose are respectively the building blocks of the backbone chains in the nucleic acids DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Small differences in the structure between D-ribose and 2-deoxy-D-ribose result in changes of the glass transition temperature T{sub g}, as well as the dielectric strength and activation enthalpy of the secondary relaxations. However, the frequency dispersion of the structural {alpha}-relaxation for the same relaxation time remains practically the same. Two secondary relaxations are present in both sugars. The slower secondary relaxation shifts to lower frequencies with increasing applied pressure, but not the faster one. This pressure dependence indicates that the slower secondary relaxation is the important and 'universal' Johari-Goldstein {beta}-relaxation of both sugars according to one of the criteria set up to classify secondary relaxations. Additional confirmation of this conclusion comes from good agreement of the observed relaxation time of the slower secondary relaxation with the primitive relaxation time calculated from the coupling model. All the dynamic properties of D-ribose and 2-deoxy-D-ribose are similar to the other monosaccharides, glucose, fructose, galactose and sorbose, except for the much larger relaxation strength of the {alpha}-relaxation of the former compared to the latter. The difference may distinguish the chemical and biological functions of D-ribose and 2-deoxy-D-ribose from the other monosaccharides.

  14. Thermal Annealing induced relaxation of compressive strain in porous GaN structures

    KAUST Repository

    Ben Slimane, Ahmed

    2012-01-01

    The effect of annealing on strain relaxation in porous GaN fabricated using electroless chemical etching is presented. The Raman shift of 1 cm-1 in phonon frequency of annealed porous GaN with respect to as-grown GaN corresponds to a relaxation of compressive strain by 0.41 ± 0.04 GPa. The strain relief promises a marked reduction in threading dislocation for subsequent epitaxial growth.

  15. Electron temperature and density relaxations during internal disruptions in TFR Tokamak plasmas

    International Nuclear Information System (INIS)

    Enriques, L.; Sand, F.

    1977-01-01

    Several diagnostics (soft X-ray, Thompson scattering, high frequency waves, and vacuum ultraviolet spectroscopy) have been used on TFR Tokamak plasmas in order to show that the soft X-ray relaxations are mainly due to electron temperature relaxations, with only small variations of the electron density. Values of ΔTsub(eo)/Tsub(eo) up to 17% and of Δnsub(eo)/nsub(eo) of a few % or less have been measured. (author)

  16. Electron temperature and density relaxations during internal disruptions in TFR Tokamak plasmas

    International Nuclear Information System (INIS)

    1976-07-01

    Several diagnostics (soft X-ray, Thomson scattering, high frequency waves, and vacuum ultraviolet spectroscopy) have been used on TFR Tokamak plasmas in order to show that the soft X-ray relaxations are mainly due to electron temperature relaxations, with only small variations of the electron density. Values of ΔTsub(e0)/Tsub(e0) up to 17% and of Δnsub(e0)/nsub(e0) of a few % or less have been measured

  17. F{sup 19} relaxation in non-magnetic hexafluorides; Contribution a l'etude de la relaxation des fluors dans les hexafluorures non magnetiques

    Energy Technology Data Exchange (ETDEWEB)

    Rigny, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-12-01

    The interesting properties of the fluorine magnetic resonance in the hexafluorides of molybdenum, tungsten and uranium, are very much due to large anisotropies of the chemical shift tensors. In the solid phases these anisotropies, the values of which are deduced from line shape studies, allow one to show that the molecules undergo hindered rotations about the metal atom. The temperature and frequency dependence of the fluorine longitudinal relaxation times shows that the relaxation is due to the molecular motion. The dynamical parameters of this motion are then deduced from the complete study of the fluorine relaxation in the rotating frame. In the liquid phases, the existence of anisotropies allows an estimation of the different contributions to the relaxation. In particular, the frequency and temperature dependence of the relaxation shows it to be dominated by the spin-rotation interaction. We have shown that the strength of this interaction can be deduced from the chemical shifts, and the angle through which the molecule rotates quasi-freely can be determined. In the hexafluorides, this angle is roughly one radian at 70 C, and with the help of this value, the friction coefficients which describe the intermolecular interactions are discussed. (author) [French] Les proprietes de la resonance magnetique des fluors dans les hexafluorures de molybdene, tungstene et uranium sont influencees par l'existence de deplacements chimiques tres anisotropes. Dans les phases solides, la valeur de cette anisotropie peut etre determinee par l'analyse des formes de raies et son existence permet de montrer que les molecules sont en rotation empechee autour de leur atome central. L'etude du temps de relaxation longitudinal en fonction de la temperature et de la frequence montre que la relaxation est due aux mouvements moleculaires, aux plus hautes temperatures. Les proprietes dynamiques du mouvement sont obtenues par l'etude complete de la relaxation spin-reseau dans le referentiel

  18. DDC Descriptor Frequencies.

    Science.gov (United States)

    Klingbiel, Paul H.; Jacobs, Charles R.

    This report summarizes the frequency of use of the 7144 descriptors used for indexing technical reports in the Defense Documentation Center (DDC) collection. The descriptors are arranged alphabetically in the first section and by frequency in the second section. The frequency data cover about 427,000 AD documents spanning the interval from March…

  19. Statistical mechanics of violent relaxation

    International Nuclear Information System (INIS)

    Shu, F.H.

    1978-01-01

    We reexamine the foundations of Lynden-Bell's statistical mechanical discussion of violent relaxation in collisionless stellar systems. We argue that Lynden-Bell's formulation in terms of a continuum description introduces unnecessary complications, and we consider a more conventional formulation in terms of particles. We then find the exclusion principle discovered by Lynden-Bell to be quantitatively important only at phase densities where two-body encounters are no longer negligible. Since the edynamical basis for the exclusion principle vanishes in such cases anyway, Lynden-Bell statistics always reduces in practice to Maxwell-Boltzmann statistics when applied to stellar systems. Lynden-Bell also found the equilibrium distribution function generally to be a sum of Maxwellians with velocity dispersions dependent on the phase density at star formation. We show that this difficulty vanishes in the particulate description for an encounterless stellar system as long as stars of different masses are initially well mixed in phase space. Our methods also demonstrate the equivalence between Gibbs's formalism which uses the microcanonical ensemble and Boltzmann's formalism which uses a coarse-grained continuum description. In addition, we clarify the concept of irreversible behavior on a macroscopic scale for an encounterless stellar system. Finally, we comment on the use of unusual macroscopic constraints to simulate the effects of incomplete relaxation

  20. Increase in salivary oxytocin and decrease in salivary cortisol after listening to relaxing slow-tempo and exciting fast-tempo music.

    Directory of Open Access Journals (Sweden)

    Yuuki Ooishi

    Full Text Available Relaxation and excitation are components of the effects of music listening. The tempo of music is often considered a critical factor when determining these effects: listening to slow-tempo and fast-tempo music elicits relaxation and excitation, respectively. However, the chemical bases that underlie these relaxation and excitation effects remain unclear. Since parasympathetic and sympathetic nerve activities are facilitated by oxytocin and glucocorticoid, respectively, we hypothesized that listening to relaxing slow-tempo and exciting fast-tempo music is accompanied by increases in the oxytocin and cortisol levels, respectively. We evaluated the change in the salivary oxytocin and cortisol levels of participants listening to slow-tempo and fast-tempo music sequences. We measured the heart rate (HR and calculated the heart rate variability (HRV to evaluate the strength of autonomic nerve activity. After listening to a music sequence, the participants rated their arousal and valence levels. We found that both the salivary oxytocin concentration and the high frequency component of the HRV (HF increased and the HR decreased when a slow-tempo music sequence was presented. The salivary cortisol level decreased and the low frequency of the HRV (LF to HF ratio (LF/HF increased when a fast-tempo music sequence was presented. The ratio of the change in the oxytocin level was correlated with the change in HF, LF/HF and HR, whereas that in the cortisol level did not show any correlation with indices of autonomic nerve activity. There was no correlation between the change in oxytocin level and self-reported emotions, while the change in cortisol level correlated with the arousal level. These findings suggest that listening to slow-tempo and fast-tempo music is accompanied by an increase in the oxytocin level and a decrease in the cortisol level, respectively, and imply that such music listening-related changes in oxytocin and cortisol are involved in

  1. Increase in salivary oxytocin and decrease in salivary cortisol after listening to relaxing slow-tempo and exciting fast-tempo music

    Science.gov (United States)

    Watanabe, Ken; Kawato, Suguru; Kashino, Makio

    2017-01-01

    Relaxation and excitation are components of the effects of music listening. The tempo of music is often considered a critical factor when determining these effects: listening to slow-tempo and fast-tempo music elicits relaxation and excitation, respectively. However, the chemical bases that underlie these relaxation and excitation effects remain unclear. Since parasympathetic and sympathetic nerve activities are facilitated by oxytocin and glucocorticoid, respectively, we hypothesized that listening to relaxing slow-tempo and exciting fast-tempo music is accompanied by increases in the oxytocin and cortisol levels, respectively. We evaluated the change in the salivary oxytocin and cortisol levels of participants listening to slow-tempo and fast-tempo music sequences. We measured the heart rate (HR) and calculated the heart rate variability (HRV) to evaluate the strength of autonomic nerve activity. After listening to a music sequence, the participants rated their arousal and valence levels. We found that both the salivary oxytocin concentration and the high frequency component of the HRV (HF) increased and the HR decreased when a slow-tempo music sequence was presented. The salivary cortisol level decreased and the low frequency of the HRV (LF) to HF ratio (LF/HF) increased when a fast-tempo music sequence was presented. The ratio of the change in the oxytocin level was correlated with the change in HF, LF/HF and HR, whereas that in the cortisol level did not show any correlation with indices of autonomic nerve activity. There was no correlation between the change in oxytocin level and self-reported emotions, while the change in cortisol level correlated with the arousal level. These findings suggest that listening to slow-tempo and fast-tempo music is accompanied by an increase in the oxytocin level and a decrease in the cortisol level, respectively, and imply that such music listening-related changes in oxytocin and cortisol are involved in physiological

  2. Increase in salivary oxytocin and decrease in salivary cortisol after listening to relaxing slow-tempo and exciting fast-tempo music.

    Science.gov (United States)

    Ooishi, Yuuki; Mukai, Hideo; Watanabe, Ken; Kawato, Suguru; Kashino, Makio

    2017-01-01

    Relaxation and excitation are components of the effects of music listening. The tempo of music is often considered a critical factor when determining these effects: listening to slow-tempo and fast-tempo music elicits relaxation and excitation, respectively. However, the chemical bases that underlie these relaxation and excitation effects remain unclear. Since parasympathetic and sympathetic nerve activities are facilitated by oxytocin and glucocorticoid, respectively, we hypothesized that listening to relaxing slow-tempo and exciting fast-tempo music is accompanied by increases in the oxytocin and cortisol levels, respectively. We evaluated the change in the salivary oxytocin and cortisol levels of participants listening to slow-tempo and fast-tempo music sequences. We measured the heart rate (HR) and calculated the heart rate variability (HRV) to evaluate the strength of autonomic nerve activity. After listening to a music sequence, the participants rated their arousal and valence levels. We found that both the salivary oxytocin concentration and the high frequency component of the HRV (HF) increased and the HR decreased when a slow-tempo music sequence was presented. The salivary cortisol level decreased and the low frequency of the HRV (LF) to HF ratio (LF/HF) increased when a fast-tempo music sequence was presented. The ratio of the change in the oxytocin level was correlated with the change in HF, LF/HF and HR, whereas that in the cortisol level did not show any correlation with indices of autonomic nerve activity. There was no correlation between the change in oxytocin level and self-reported emotions, while the change in cortisol level correlated with the arousal level. These findings suggest that listening to slow-tempo and fast-tempo music is accompanied by an increase in the oxytocin level and a decrease in the cortisol level, respectively, and imply that such music listening-related changes in oxytocin and cortisol are involved in physiological

  3. Microscopic dynamics and relaxation processes in liquid hydrogen fluoride

    International Nuclear Information System (INIS)

    Angelini, R.; Giura, P.; Monaco, G.; Sette, F.; Fioretto, D.; Ruocco, G.

    2004-01-01

    Inelastic x-ray scattering and Brillouin light scattering measurements of the dynamic structure factor of liquid hydrogen fluoride have been performed in the temperature range T=214-283 K. The data, analyzed using a viscoelastic model with a two time-scale memory function, show a positive dispersion of the sound velocity c(Q) between the low frequency value c 0 (Q) and the high frequency value c ∞α (Q). This finding confirms the existence of a structural (α) relaxation directly related to the dynamical organization of the hydrogen bonds network of the system. The activation energy E a of the process has been extracted by the analysis of the temperature behavior of the relaxation time τ α (T) that follows an Arrhenius law. The obtained value for E a , when compared with that observed in another hydrogen bond liquid as water, suggests that the main parameter governing the α-relaxation process is the number of hydrogen bonds per molecule

  4. Dielectric relaxations in non-metallic materials related to Y-Ba-Cu-O superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bennani, H.; Pilet, J.C. (Lab. Instrumentation, Rennes-1 Univ., 35 (France)); Guilloux-Viry, M.; Perrin, C.; Perrin, A.; Sergent, M. (Lab. de Chimie Minerale B, C.N.R.S., 35 - Rennes (France))

    1990-10-15

    In relation with high Tc superconducting material studies, dielectric measurements have been carried out, in the frequency range 10 Hz - 100 kHz, on two powdered compounds belonging to the Y-Ba-Cu-O system. The non-metallic tetragonal phases YBa{sub 2}Cu{sub 3}O{sub 6+x} exhibit dielectric relaxations: for the studied samples (x<0.4) the activation energy U is observed in the range 0.5relaxation has been detected at higher temperature, near 400 K. Additional measurements to 77 K at 1 MHz give a value of dielectric constant {epsilon}'=3 and a low loss factor tg{delta}=10{sup -3}: this latter value is comparable to the one of lanthanum gallate recently proposed as a substrate for high frequency uses. This result enhances the previously reported potential interest of this material as substrate or buffer layer for preparation of superconducting thin films for high frequency applications. (orig.).

  5. Paramagnetic relaxation effects in perturbed angular correlations for arbitrary electronic relaxation time

    International Nuclear Information System (INIS)

    Chopin, C.; Spanjaard, D.; Hartmann-Boutron, F.

    1975-01-01

    Previous perturbation treatments of paramagnetic relaxation effects in γγ PAC were limited to the case of very short electronic relaxation times. This limitation is circumvented by invoking a new perturbation theory recently elaborated by Hirst and others for handling relaxation effects in Moessbauer spectra. Under the assumption of spherical electronic relaxation the perturbation factors are computed as functions of certain relaxation parameters which are directly related to the microscopic relaxation Hamiltonian. The results are compared to those of the stochastic theory of Scherer and Blume [fr

  6. Association of lumbar spine stiffness and flexion-relaxation phenomenon with patient-reported outcomes in adults with chronic low back pain - a single-arm clinical trial investigating the effects of thrust spinal manipulation.

    Science.gov (United States)

    Xia, Ting; Long, Cynthia R; Vining, Robert D; Gudavalli, Maruti R; DeVocht, James W; Kawchuk, Gregory N; Wilder, David G; Goertz, Christine M

    2017-06-09

    Spinal manipulation (SM) is used commonly for treating low back pain (LBP). Spinal stiffness is routinely assessed by clinicians performing SM. Flexion-relaxation ratio (FRR) was shown to distinguish between LBP and healthy populations. The primary objective of this study was to examine the association of these two physiological variables with patient-reported pain intensity and disability in adults with chronic LBP (>12 weeks) receiving SM. A single-arm trial provided 12 sessions of side-lying thrust SM in the lumbosacral region over 6 weeks. Inclusion criteria included 21-65 years old, Roland-Morris Disability Questionnaire (RMDQ) score ≥ 6 and numerical pain rating score ≥ 2. Spinal stiffness and FRR were assessed pre-treatment at baseline, after 2 weeks and after 6 weeks of treatment. Lumbar spine global stiffness (GS) were calculated from the force-displacement curves obtained using i) hand palpation, ii) a hand-held device, and iii) an automated indenter device. Lumbar FRR was assessed during trunk flexion-extension using surface electromyography. The primary outcomes were RMDQ and pain intensity measured by visual analog scale (VAS). Mixed-effects regression models were used to analyze the data. The mean age of the 82 participants was 45 years; 48% were female; and 84% reported LBP >1 year. The mean (standard deviation) baseline pain intensity and RMDQ were 46.1 (18.1) and 9.5 (4.3), respectively. The mean reduction (95% confidence interval) after 6 weeks in pain intensity and RMDQ were 20.1 mm (14.1 to 26.1) and 4.8 (3.7 to 5.8). There was a small change over time in the palpatory GS but not in the hand-held or automated GS, nor in FRR. The addition of each physiologic variable did not affect the model-estimated changes in VAS or RMDQ over time. There was no association seen between physiological variables and LBP intensity. Higher levels of hand-held GS at L3 and automated GS were significantly associated with higher levels of RMDQ (p

  7. Fundamentals of ionic conductivity relaxation gained from study of procaine hydrochloride and procainamide hydrochloride at ambient and elevated pressure.

    Science.gov (United States)

    Wojnarowska, Z; Swiety-Pospiech, A; Grzybowska, K; Hawelek, L; Paluch, M; Ngai, K L

    2012-04-28

    The pharmaceuticals, procaine hydrochloride and procainamide hydrochloride, are glass-forming as well as ionically conducting materials. We have made dielectric measurements at ambient and elevated pressures to characterize the dynamics of the ion conductivity relaxation in these pharmaceuticals, and calorimetric measurements for the structural relaxation. Perhaps due to their special chemical and physical structures, novel features are found in the ionic conductivity relaxation of these pharmaceuticals. Data of conductivity relaxation in most ionic conductors when represented by the electric loss modulus usually show a single resolved peak in the electric modulus loss M(")(f) spectra. However, in procaine hydrochloride and procainamide hydrochloride we find in addition another resolved loss peak at higher frequencies over a temperature range spanning across T(g). The situation is analogous to many non-ionic glass-formers showing the presence of the structural α-relaxation together with the Johari-Goldstein (JG) β-relaxation. Naturally the analogy leads us to name the slower and faster processes resolved in procaine hydrochloride and procainamide hydrochloride as the primary α-conductivity relaxation and the secondary β-conductivity relaxation, respectively. The analogy of the β-conductivity relaxation in procaine HCl and procainamide HCl with JG β-relaxation in non-ionic glass-formers goes further by the finding that the β-conductivity is strongly related to the α-conductivity relaxation at temperatures above and below T(g). At elevated pressure but compensated by raising temperature to maintain α-conductivity relaxation time constant, the data show invariance of the ratio between the β- and the α-conductivity relaxation times to changes of thermodynamic condition. This property indicates that the β-conductivity relaxation has fundamental importance and is indispensable as the precursor of the α-conductivity relaxation, analogous to the relation found

  8. Cross relaxation in nitroxide spin labels

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    Cross relaxation, and mI-dependence of the intrinsic electron spin-lattice relaxation rate We, are incorporated explicitly into the rate equations for the electron-spin population differences that govern the saturation behaviour of 14N- and 15N-nitroxide spin labels. Both prove important in spin......-label EPR and ELDOR, particularly for saturation recovery studies. Neither for saturation recovery, nor for CW-saturation EPR and CW-ELDOR, can cross relaxation be described simply by increasing the value of We, the intrinsic spin-lattice relaxation rate. Independence of the saturation recovery rates from...... the hyperfine line pumped or observed follows directly from solution of the rate equations including cross relaxation, even when the intrinsic spin-lattice relaxation rate We is mI-dependent....

  9. Report on a 2009 mini-demonstration of the ARG-US Radio Frequency Identification (RFID) system in transportation

    International Nuclear Information System (INIS)

    Tsai, H.; Chen, K.; Jusko, M.; Craig, B.; Liu, Y.

    2009-01-01

    The Packaging Certification Program (PCP) of the U.S. Department of Energy (DOE) Environmental Management (EM), Office of Packaging and Transportation (EM-14), has developed a radio frequency identification (RFID) tracking and monitoring system for the management of nuclear materials during storage and transportation. The system, developed by the PCP team at Argonne National Laboratory, consists of hardware (Mk-series sensor tags, fixed and handheld readers, form factor for multiple drum types, seal integrity sensors, and enhanced battery management), software (application programming interface, ARG-US software for local and remote/web applications, secure server and database management), and cellular/satellite communication interfaces for vehicle tracking and item monitoring during transport. The ability of the above system to provide accurate, real-time tracking and monitoring of the status of multiple, certified containers of nuclear materials has been successfully demonstrated in a week-long, 1,700-mile DEMO performed in April 2008. While the feedback from the approximately fifty (50) stakeholders who participated in and/or observed the DEMO progression were very positive and encouraging, two major areas of further improvements - system integration and web application enhancement - were identified in the post-DEMO evaluation. The principal purpose of the MiniDemo described in this report was to verify these two specific improvements. The MiniDemo was conducted on August 28, 2009. In terms of system integration, a hybrid communication interface - combining the RFID item-monitoring features and a commercial vehicle tracking system by Qualcomm - was developed and implemented. In the MiniDemo, the new integrated system worked well in reporting tag status and vehicle location accurately and promptly. There was no incompatibility of components. The robust commercial communication gear, as expected, helped improve system reliability. The MiniDemo confirmed that system

  10. Report on a 2009 mini-demonstration of the ARG-US Radio Frequency Identification (RFID) system in transportation.

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Chen, K.; Jusko, M.; Craig, B.; Liu, Y.; Decision and Information Sciences

    2009-11-23

    The Packaging Certification Program (PCP) of the U.S. Department of Energy (DOE) Environmental Management (EM), Office of Packaging and Transportation (EM-14), has developed a radio frequency identification (RFID) tracking and monitoring system for the management of nuclear materials during storage and transportation. The system, developed by the PCP team at Argonne National Laboratory, consists of hardware (Mk-series sensor tags, fixed and handheld readers, form factor for multiple drum types, seal integrity sensors, and enhanced battery management), software (application programming interface, ARG-US software for local and remote/web applications, secure server and database management), and cellular/satellite communication interfaces for vehicle tracking and item monitoring during transport. The ability of the above system to provide accurate, real-time tracking and monitoring of the status of multiple, certified containers of nuclear materials has been successfully demonstrated in a week-long, 1,700-mile DEMO performed in April 2008. While the feedback from the approximately fifty (50) stakeholders who participated in and/or observed the DEMO progression were very positive and encouraging, two major areas of further improvements - system integration and web application enhancement - were identified in the post-DEMO evaluation. The principal purpose of the MiniDemo described in this report was to verify these two specific improvements. The MiniDemo was conducted on August 28, 2009. In terms of system integration, a hybrid communication interface - combining the RFID item-monitoring features and a commercial vehicle tracking system by Qualcomm - was developed and implemented. In the MiniDemo, the new integrated system worked well in reporting tag status and vehicle location accurately and promptly. There was no incompatibility of components. The robust commercial communication gear, as expected, helped improve system reliability. The MiniDemo confirmed that system

  11. Structural relaxation in annealed hyperquenched basaltic glasses

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, John C.; Potuzak, M.

    2012-01-01

    The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary...... relaxation is activated at the same temperature regardless of the initial departure from equilibrium. The analysis of secondary relaxation at different annealing temperatures provides insights into the enthalpy recovery of HQ glasses....

  12. Dielectric relaxation and ac conductivity behaviour of polyvinyl alcohol–HgSe quantum dot hybrid films

    International Nuclear Information System (INIS)

    Sinha, Subhojyoti; Chatterjee, Sanat Kumar; Meikap, Ajit Kumar; Ghosh, Jiten

    2014-01-01

    Here we report a comparative study on the dielectric relaxation and ac conductivity behaviour of pure polyvinyl alcohol (PVA) and PVA–mercury selenide (HgSe) quantum dot hybrid films in the temperature range 298 K ⩽ T ⩽ 420 K and in the frequency range 100 Hz ⩽ f ⩽ 1 MHz. The prepared nanocomposite exhibits a larger dielectric constant as compared to the pure PVA. The real and imaginary parts of the dielectric constants were found to fit appreciably with the modified Cole–Cole equation, from which temperature-dependent values of the relaxation times, free charge carrier conductivity and space charge carrier conductivity were calculated. The relaxation time decreases with the quantum dot's inclusion in the PVA matrix and with an increase in temperature, whereas free charge carrier conductivity and space charge carrier conductivity increases with an increase in temperature. An increase in ac conductivity for the nanocomposites has also been observed, while the charge transport mechanism was found to follow the correlated barrier hopping model in both cases. An easy-path model with a suitable electrical equivalent circuit has been employed to analyse the temperature-dependent impedance spectra. The imaginary part of the complex electric modulus spectra exhibit an asymmetric nature and a non-Debye type of behaviour, which has been elucidated considering a generalized susceptibility function. The electric modulus spectra of the nanocomposite demonstrate a smaller amplitude and broader width, as compared to the pure PVA sample. (paper)

  13. Dielectric Relaxation of Water: Theory and Experiment

    International Nuclear Information System (INIS)

    Adhikari, Narayan Prasad; Paudyal, Harihar; Johri, Manoj

    2010-06-01

    We have studied the hydrogen bond dynamics and methods for evaluation of probability and relaxation time for hydrogen bond network. Further, dielectric relaxation time has been calculated by using a diagonalization procedure by obtaining eigen values (inverse of relaxation time) of a master equation framed on the basis of Fokker-Planck equations. Microwave cavity spectrometer has been described to make measurements of relaxation time. Slater's perturbation equations are given for the analysis of the data. A comparison of theoretical and experimental data shows that there is a need for improvements in the theoretical model and experimental techniques to provide exact information about structural properties of water. (author)

  14. Influences of irradiating on spectrum temporary to relaxations

    International Nuclear Information System (INIS)

    Mahmudov, A.Y.; Akhmedov, F.A.

    2002-01-01

    Full text: Generality of chain macromolecular system construction allows to identify a majority of features of polymers of like nature. So on considered in given work irradiated model no condition on descending in not put. Model consists of gaussian chains with (N x m) numbers (from them N - a number of chains and m - a number an beads on chains, which are distinguished one from another by the degree a mobility) potential interaction centres with the surround environment. The interaction carries of inter and intramolecular nature , including and hydrogen bond. Between these centres there are constant and casual contacts. For terminal volume and terminal time possible to neglect influences casual bonds of fluctuation.Let number of constant contacts is equally n. Changing of number of contacts under the action of irradiating carries a kinetic nature and so it is described by the differential equation, which parameters are formation frequencies and destroying the contacts. Decision of this equation allows to calculate a complex module of bounce, on which possible judge on velocities of relaxation process irradiated polymer. At the equality unit a relations of frequencies of formation and destroying of the contact occurs as it were a dynamic balance and spectrum temporary relaxations corresponds a spectrum non radiating models. An accumulation of energy occurs under small energy of irradiating in the in that nodes, which encircled smaller number nodes. So small doses of irradiating a polymer show a wing of spectrum temporary to relaxations in the lion. Comparison of obtained formula with available in literature by data has shown that frequency of forming the contacts much less, than their destruction frequency

  15. Relaxation and health-related quality of life in multiple sclerosis: the example of autogenic training.

    Science.gov (United States)

    Sutherland, Georgina; Andersen, Mark B; Morris, Tony

    2005-06-01

    This study was a pilot project to explore the effect of an autogenic training program (AT; a relaxation intervention) on the health-related quality of life (HRQOL) and well-being for people with multiple sclerosis. Participants either met weekly for sessions in AT for 10 weeks (n = 11) or were assigned to the control group (n = 11). The AT group was also asked to practice the technique daily at home. Scales designed to measure HRQOL and aspects of well-being (mood and depressed affect) were taken preintervention and at week 8 of the 10-week program. ANCOVAs using a measure of social support and pretest scores as covariates revealed that at the posttest the AT group reported more energy and vigor than the control group and were less limited in their roles due to physical and emotional problems. Future research should involve studies conducted over an extended period, together with sufficiently sized samples to explore the effect of frequency of practice of relaxation training on HRQOL and well-being for people with multiple sclerosis.

  16. Pair plasma relaxation time scales.

    Science.gov (United States)

    Aksenov, A G; Ruffini, R; Vereshchagin, G V

    2010-04-01

    By numerically solving the relativistic Boltzmann equations, we compute the time scale for relaxation to thermal equilibrium for an optically thick electron-positron plasma with baryon loading. We focus on the time scales of electromagnetic interactions. The collisional integrals are obtained directly from the corresponding QED matrix elements. Thermalization time scales are computed for a wide range of values of both the total-energy density (over 10 orders of magnitude) and of the baryonic loading parameter (over 6 orders of magnitude). This also allows us to study such interesting limiting cases as the almost purely electron-positron plasma or electron-proton plasma as well as intermediate cases. These results appear to be important both for laboratory experiments aimed at generating optically thick pair plasmas as well as for astrophysical models in which electron-positron pair plasmas play a relevant role.

  17. Relaxing Chosen-Ciphertext Security

    DEFF Research Database (Denmark)

    Canetti, Ran; Krawczyk, Hugo; Nielsen, Jesper Buus

    2003-01-01

    Security against adaptive chosen ciphertext attacks (or, CCA security) has been accepted as the standard requirement from encryption schemes that need to withstand active attacks. In particular, it is regarded as the appropriate security notion for encryption schemes used as components within...... general protocols and applications. Indeed, CCA security was shown to suffice in a large variety of contexts. However, CCA security often appears to be somewhat too strong: there exist encryption schemes (some of which come up naturally in practice) that are not CCA secure, but seem sufficiently secure...... “for most practical purposes.” We propose a relaxed variant of CCA security, called Replayable CCA (RCCA) security. RCCA security accepts as secure the non-CCA (yet arguably secure) schemes mentioned above; furthermore, it suffices for most existing applications of CCA security. We provide three...

  18. Validity and reliability of parental report of frequency, severity and risk factors of urinary tract infection and urinary incontinence in children.

    Science.gov (United States)

    Sureshkumar, Premala; Cumming, Robert G; Craig, Jonathan C

    2006-06-01

    We describe the validity and reliability of a questionnaire designed to determine frequency, severity and risk factors of urinary tract infection and daytime urinary incontinence in primary school-age children. Based on published validated questionnaires and advice from content experts, a questionnaire was developed and piloted in children attending outpatient clinics. Construct validity for parent report of frequency and severity of daytime urinary incontinence was tested by comparison with a daily accident diary in 52 primary school children, and criterion validity of parent report for UTI was verified by comparison with the reference standard (urine culture) in 100 primary school children. Test-retest reliability of the questionnaire was assessed in 106 children from primary schools. There was excellent agreement between the questionnaire and accident diary in severity (weighted kappa 0.94, 95% confidence intervals 0.85 to 1.03) and frequency of daytime urinary incontinence (0.88, 0.7 to 1.0). Parents reported urinary tract infection in 15% of children, compared to a positive urine culture in 8% (sensitivity 100% and specificity 68.5%). Test-retest reliability of the questionnaire was excellent (mean k 0.78, range 0.61 to 1.00). Parents overreport UTI by about 2-fold but can recall frequency and severity of daytime urinary incontinence well during a 3-month period. The developed questionnaire is a valid tool to estimate frequency, severity and risk factors of daytime urinary incontinence and UTI in primary school children.

  19. Mechanical Spectroscopy: Some Applications On Structural Changes And Relaxation Dynamics In Soft Matter

    Directory of Open Access Journals (Sweden)

    Wu Xuebang

    2015-09-01

    Full Text Available The general trend in soft matter is to study systems of increasing complexity covering a wide range in time and frequency. Mechanical spectroscopy is a powerful tool for understanding the structure and relaxation dynamics of these materials over a large temperature range and frequency scale. In this work, we collect a few recent applications using low-frequency mechanical spectroscopy for elucidating the structural changes and relaxation dynamics in soft matter, largely based on the author’s group. We illustrate the potential of mechanical spectroscopy with three kinds of soft materials: colloids, polymers and granular systems. Examples include structural changes in colloids, segmental relaxations in amorphous polymers, and resonant dissipation of grain chains in three-dimensional media. The present work shows that mechanical spectroscopy has been applied as a necessary and complementary tool to study the dynamics of such complex systems.

  20. Anisotropy of the nuclear magnetic relaxation times induced in solid 3He by modulation of the dipolar interactions

    International Nuclear Information System (INIS)

    Deville, G.

    1976-01-01

    Anisotropic nuclear relaxation times have been measured in solid 3 He samples grown at constant pressure, in the Larmor frequency range 1.5MHz-5MHz where the main relaxation mechanism is the modulation of the dipolar interaction by exchange or by motion of the vacancies. The second order calculation made by Harris for the exchange induced relaxation regime is extended to the regime where vacancy motion dominates. The theory is further refined by considering the fourth moment anisotropy effect on the spectral densities. This latter calculation yields a frequency dependent anisotropic contribution to T 1 which agrees qualitatively with the data, unlike the simpler results by Harris [fr

  1. Smoking, leisure-time exercise and frequency of self-reported common cold among the general population in northeastern China: a cross-sectional study.

    Science.gov (United States)

    Zhou, Ge; Liu, Hongjian; He, Minfu; Yue, Mengjia; Gong, Ping; Wu, Fangyuan; Li, Xuanxuan; Pang, Yingxin; Yang, Xiaodi; Ma, Juan; Liu, Meitian; Li, Jinghua; Zhang, Xiumin

    2018-02-27

    Physical activity (PA) and smoking have been reported to be associated with the duration and severity of common cold symptoms. However, few studies have addressed the associations between the frequency of leisure-time exercise, cigarette smoking status and the frequency of the common cold in a cold area. This study was designed to investigate these issues in northeastern China. This cross-sectional study included individuals who participated in a regular health examination conducted in Jilin Province, China. Information on episodes of the common cold, the frequency of leisure-time exercise and cigarette smoking status in the past year were collected by self-administered health questionnaires. Ordinal logistic regression models were used to analyse the associations between the frequency of leisure-time exercise, cigarette smoking status and the retrospective frequency of common cold. A total of 1413 employees participated in the study, with an average age of 38.92 ± 9.04 years and 44.4% of them were male. Of all participants, 80.8% reported having experienced the common cold in the past year. After adjustment, the risk of suffering from the common cold more than once (odds ratios (ORs), 1.59; 95% confidence interval (CI), 1.27-1.99) in passive smokers was 1.59 times as high as that in non-smokers. Nevertheless, the results of the adjusted analysis showed no statistically significant relation between current smoking and the frequency of the common cold. A high frequency of leisure-time exercise (≥3 days/week) was associated with a 26% reduced risk of having at least one episode of the common cold (OR, 0.74; 95% CI, 0.55-0.98) compared with a low frequency group (exercise appears not to be obvious (current smokers: OR, 0.68; 95% CI, 0.33-1.43; passive smokers: OR, 1.15; 95% CI, 0.69-1.93). Passive smoking was associated with a higher risk of having self-reported common cold at least once, while a high frequency of leisure-time exercise was related to a lower

  2. The Effects of Progressive Relaxation and Music on Attention, Relaxation, and Stress Responses: An Investigation of the Cognitive-Behavioral Model of Relaxation

    National Research Council Canada - National Science Library

    Scheufele, Peter

    1999-01-01

    ...) suggested that stress management techniques have specific effects A compromise position suggests that the specific effects of relaxation techniques are superimposed upon a general relaxation response...

  3. Non-linear effects in the Snoek relaxation of Nb-O

    International Nuclear Information System (INIS)

    Hermida, E.B.; Povolo, F.

    1996-01-01

    Internal friction peaks measured as a function of temperature or frequency have been associated to non-linear processes only after studying how the amplitude of the applied stress affects the relaxation process. Here it is demonstrated that the partial derivative of the internal friction with respect to the frequency at constant temperature is a useful tool to determine that non-linear effects are involved. This analysis applied to actual data of the Snoek relaxation in Nb-O, reveals that at high interstitial contents non-linear effects appear. (orig.)

  4. Experimental comparison of diffusional nuclear magnetic relaxation theories using ZrHsub(1.684)

    International Nuclear Information System (INIS)

    Korn, C.; Goren, S.

    1984-01-01

    The spin-lattice relaxation time of hydrogen in ZrHsub(1.684) was measured at a resonance frequency of 16.69 MHz as a function of temperature in a temperature range where the major relaxation mechanism was hydrogen diffusion. This parameter was used to calculate the hydrogen jump frequencies using the theories of Bloembergen, Purcell and Pound (BPP), of Bustard and of Barton and Sholl. A comparison shows that the BPP theory gives results closest to Arrhenius-type behaviour. The diffusional activation energy was found to be 13.3 kcal mol -1 . (Auth.)

  5. Relaxation property of the fractional Brownian particle

    International Nuclear Information System (INIS)

    Wang Litan; Lung, C.W.

    1988-08-01

    Dynamic susceptibility of a diffusion system associated with the fractional Brownian motion (fBm) was examined for the fractal property of the Non-Debye relaxation process. The comparisons between fBm and other approaches were made. Anomalous diffusion and the Non-Debye relaxation processes were discussed with this approach. (author). 8 refs, 1 fig

  6. Lifshitz quasinormal modes and relaxation from holography

    NARCIS (Netherlands)

    Sybesma, Watse|info:eu-repo/dai/nl/369283074; Vandoren, Stefan|info:eu-repo/dai/nl/304830739

    2015-01-01

    We obtain relaxation times for field theories with Lifshitz scaling and with holographic duals Einstein-Maxwell-Dilaton gravity theories. This is done by computing quasinormal modes of a bulk scalar field in the presence of Lifshitz black branes. We determine the relation between relaxation time and

  7. Superparamagnetic relaxation of weakly interacting particles

    DEFF Research Database (Denmark)

    Mørup, Steen; Tronc, Elisabeth

    1994-01-01

    The influence of particle interactions on the superparamagnetic relaxation time has been studied by Mossbauer spectroscopy in samples of maghemite (gamma-Fe2O3) particles with different particle sizes and particle separations. It is found that the relaxation time decreases with decreasing particl...

  8. Models of Flux Tubes from Constrained Relaxation

    Indian Academy of Sciences (India)

    tribpo

    J. Astrophys. Astr. (2000) 21, 299 302. Models of Flux Tubes from Constrained Relaxation. Α. Mangalam* & V. Krishan†, Indian Institute of Astrophysics, Koramangala,. Bangalore 560 034, India. *e mail: mangalam @ iiap. ernet. in. † e mail: vinod@iiap.ernet.in. Abstract. We study the relaxation of a compressible plasma to ...

  9. Superparamagnetic relaxation in alpha-Fe particles

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen; Pedersen, Michael Stanley

    1998-01-01

    The superparamagnetic relaxation time of carbon-supported alpha-Fe particles with an average size of 3.0 Mm has been studied over a large temperature range by the use of Mossbauer spectroscopy combined with AC and DC magnetization measurements. It is found that the relaxation time varies...

  10. Baryogenesis via Elementary Goldstone Higgs Relaxation

    DEFF Research Database (Denmark)

    Gertov, Helene; Pearce, Lauren; Sannino, Francesco

    2016-01-01

    We extend the relaxation mechanism to the Elementary Goldstone Higgs framework. Besides studying the allowed parameter space of the theory we add the minimal ingredients needed for the framework to be phenomenologically viable. The very nature of the extended Higgs sector allows to consider very ...... but radiatively generated, it is possible to generate the observed matter-antimatter asymmetry via the relaxation mechanism....

  11. A nuclear magnetic relaxation study on internal motion of polyelectrolytes in solution

    International Nuclear Information System (INIS)

    Schriever, J.

    1977-01-01

    The aim of this thesis is to investigate the significance and the amount of information which can be extracted from the study of frequency dependence of magnetic relaxation rates in solutions of a synthetic macromolecule. Solutions of poly(methacrylic acid), PMA, in water were chosen as the object of the present work. A short survey of nuclear magnetic relaxation in solutions of simple macromolecules is presented. Results obtained by continuous wave experiments on PMA solutions are shown (viz. the information about the transverse relaxation from line width analysis of 60 MHz proton spectra). Water enriched in 17 O is used in magnetic relaxation studies; the results of the determination of hydrogen lifetimes in aqueous solutions of acetic acid and poly(methacrylic acid) are given. The possibility of obtaining information about the dynamics of deuterons in the acid side groups of weak polyacids by measuring deuteron relaxation in heavy water solutions of those acids is considered. The use of deuteron relaxation rate experiments on solutions of selectively methylene deuterated poly(methacrylic acid), [-CD 2 -CCH 3 COOH-]n, is demonstrated and the backbone methylene C-atom motion is charachterized. The magne-tic relaxation of nuclei in the side groups of methylene deuterated PMA, viz. protons in the methyland deuterons in the acid side groups is presented

  12. Generalized extended Navier-Stokes theory: multiscale spin relaxation in molecular fluids.

    Science.gov (United States)

    Hansen, J S

    2013-09-01

    This paper studies the relaxation of the molecular spin angular velocity in the framework of generalized extended Navier-Stokes theory. Using molecular dynamics simulations, it is shown that for uncharged diatomic molecules the relaxation time decreases with increasing molecular moment of inertia per unit mass. In the regime of large moment of inertia the fast relaxation is wave-vector independent and dominated by the coupling between spin and the fluid streaming velocity, whereas for small inertia the relaxation is slow and spin diffusion plays a significant role. The fast wave-vector-independent relaxation is also observed for highly packed systems. The transverse and longitudinal spin modes have, to a good approximation, identical relaxation, indicating that the longitudinal and transverse spin viscosities have same value. The relaxation is also shown to be isomorphic invariant. Finally, the effect of the coupling in the zero frequency and wave-vector limit is quantified by a characteristic length scale; if the system dimension is comparable to this length the coupling must be included into the fluid dynamical description. It is found that the length scale is independent of moment of inertia but dependent on the state point.

  13. Electron paramagnetic relaxation studies of free radicals in. gamma. -irradiated DNA

    Energy Technology Data Exchange (ETDEWEB)

    Kuwabara, M; Yoshi, G [Hokkaido Univ., Sapporo (Japan)

    1980-01-01

    Using the continuous microwave power saturation method the T/sub 1/ spin-lattice relaxation time and T/sub 2/ spin-spin relaxation time for DNA radicals (measured at 297/sup 0/K) are reported. Identical experiments carried out on thymidine-5'-monophosphate sodium salt (TMP) and deoxycytidine-5'-monophosphate sodium salt (dCMP) are also reported. Irradiated DNA produces TMP radicals on the base moiety and dCMP radicals on the sugar moiety. Comparing the relaxation times of DNA with those of TMP and dCMP provided a reliable analysis of the nature of DNA radicals.

  14. Stress relaxation under cyclic electron irradiation

    International Nuclear Information System (INIS)

    Bystrov, L.N.; Reznitskij, M.E.

    1990-01-01

    The kinetics of deformation process in a relaxating sample under 2 MeV electron cyclic irradiation was studied experimentally. The Al-Mg alloys with controllable and different (in dislocation density precipitate presence and their character) structure were used in experiments. It was established that after the beam was switched on the deformation rate increased sharply and then, during prolonged irradiation, in a gradual manner. After the switching-off the relaxation rate decreases by jumps up to values close to extrapolated rates of pre-radiation relaxation. The exhibition of these effects with radiation switching-off and switchin-on is dependent on the initial rate of thermal relaxation, the test temperature, the preliminary cold deformation and the dominating deformation dislocation mechanism. The preliminary cold deformation and test temperature elevation slightly decrease the effect of instantaneous relaxation acceleration with the irradiation switch-on. 17 refs., 5 figs

  15. Relaxation dynamics following transition of solvated electrons

    International Nuclear Information System (INIS)

    Barnett, R.B.; Landman, U.; Nitzan, A.

    1989-01-01

    Relaxation dynamics following an electronic transition of an excess solvated electron in clusters and in bulk water is studied using an adiabatic simulation method. In this method the solvent evolves classically and the electron is constrained to a specified state. The coupling between the solvent and the excess electron is evaluated via the quantum expectation value of the electron--water molecule interaction potential. The relaxation following excitation (or deexcitation) is characterized by two time scales: (i) a very fast (/similar to/20--30 fs) one associated with molecular rotations in the first solvation shell about the electron, and (ii) a slower stage (/similar to/200 fs), which is of the order of the longitudinal dielectric relaxation time. The fast relaxation stage exhibits an isotope effect. The spectroscopical consequences of the relaxation dynamics are discussed

  16. Anomalous enthalpy relaxation in vitreous silica

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    2015-01-01

    scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...... relaxation compared to fragile oxide systems. The anomalous enthalpy relaxation of vitreous silica is discovered by performing the hyperquenching-annealing-calorimetry experiments. We argue that the strong systems like vitreous silica and vitreous Germania relax in a structurally cooperative manner, whereas...... the fragile ones do in a structurally independent fashion. We discuss the origin of the anomalous enthalpy relaxation in the HQ vitreous silica....

  17. Vibrational and Rotational Energy Relaxation in Liquids

    DEFF Research Database (Denmark)

    Petersen, Jakob

    Vibrational and rotational energy relaxation in liquids are studied by means of computer simulations. As a precursor for studying vibrational energy relaxation of a solute molecule subsequent to the formation of a chemical bond, the validity of the classical Bersohn-Zewail model for describing......, the vibrational energy relaxation of I2 subsequent to photodissociation and recombination in CCl4 is studied using classical Molecular Dynamics simulations. The vibrational relaxation times and the time-dependent I-I pair distribution function are compared to new experimental results, and a qualitative agreement...... is found in both cases. Furthermore, the rotational energy relaxation of H2O in liquid water is studied via simulations and a power-and-work analysis. The mechanism of the energy transfer from the rotationally excited H2O molecule to its water neighbors is elucidated, i.e. the energy-accepting degrees...

  18. Cross-relaxation solid state lasers

    International Nuclear Information System (INIS)

    Antipenko, B.M.

    1989-01-01

    Cross-relaxation functional diagrams provide a high quantum efficiency for pumping bands of solid state laser media and a low waste heat. A large number of the cross-relaxation mechanisms for decay rare earth excited states in crystals have been investigated. These investigations have been a starting-point for development of the cross-relaxation solid state lasers. For example, the cross-relaxation interactions, have been used for the laser action development of LiYF 4 :Gd-Tb. These interactions are important elements of the functional diagrams of the 2 μm Ho-doped media sensitized with Er and Tm and the 3 μm Er-doped media. Recently, new efficient 2 μm laser media with cross-relaxation pumping diagrams have been developed. Physical aspects of these media are the subject of this paper. A new concept of the Er-doped medium, sensitized with Yb, is illustrated

  19. The creep compliance, the relaxation modulus and the complex compliance of linear viscoelastic, homogeneous, isotropic materials

    International Nuclear Information System (INIS)

    Wong, P.K.

    1989-01-01

    This paper reports on a study to obtain the creep compliance, the relaxation modulus and the complex compliance derived from the concept of mechanical resistance for the constitutive equation of a class of linear viscoelastic, homogeneous, isotropic materials

  20. Anomalous relaxation in binary mixtures: a dynamic facilitation picture

    International Nuclear Information System (INIS)

    Moreno, A J; Colmenero, J

    2007-01-01

    Recent computational investigations of polymeric and non-polymeric binary mixtures have reported anomalous relaxation features when both components exhibit very different mobilities. Anomalous relaxation is characterized by sublinear power-law behaviour for mean-squared displacements, logarithmic decay in dynamic correlators, and a striking concave-to-convex crossover in the latter by tuning the relevant control parameter, in analogy with predictions of the mode-coupling theory for state points close to higher-order transitions. We present Monte Carlo simulations on a coarse-grained model for relaxation in binary mixtures. The liquid structure is substituted by a three-dimensional array of cells. A spin variable is assigned to each cell, representing unexcited and excited local states of a mobility field. Changes in local mobility (spin flip) are permitted according to kinetic constraints determined by the mobilities of the neighbouring cells. We introduce two types of cell ('fast' and 'slow') with very different rates for spin flip. This coarse-grained model qualitatively reproduces the mentioned anomalous relaxation features observed for real binary mixtures

  1. Deconvolution of astronomical images using SOR with adaptive relaxation.

    Science.gov (United States)

    Vorontsov, S V; Strakhov, V N; Jefferies, S M; Borelli, K J

    2011-07-04

    We address the potential performance of the successive overrelaxation technique (SOR) in image deconvolution, focusing our attention on the restoration of astronomical images distorted by atmospheric turbulence. SOR is the classical Gauss-Seidel iteration, supplemented with relaxation. As indicated by earlier work, the convergence properties of SOR, and its ultimate performance in the deconvolution of blurred and noisy images, can be made competitive to other iterative techniques, including conjugate gradients, by a proper choice of the relaxation parameter. The question of how to choose the relaxation parameter, however, remained open, and in the practical work one had to rely on experimentation. In this paper, using constructive (rather than exact) arguments, we suggest a simple strategy for choosing the relaxation parameter and for updating its value in consecutive iterations to optimize the performance of the SOR algorithm (and its positivity-constrained version, +SOR) at finite iteration counts. We suggest an extension of the algorithm to the notoriously difficult problem of "blind" deconvolution, where both the true object and the point-spread function have to be recovered from the blurred image. We report the results of numerical inversions with artificial and real data, where the algorithm is compared with techniques based on conjugate gradients. In all of our experiments +SOR provides the highest quality results. In addition +SOR is found to be able to detect moderately small changes in the true object between separate data frames: an important quality for multi-frame blind deconvolution where stationarity of the object is a necesessity.

  2. Dielectric and mechanical relaxation in isooctylcyanobiphenyl (8*OCB)

    Energy Technology Data Exchange (ETDEWEB)

    Pawlus, S; Mierzwa, M; Paluch, M; Rzoska, S J [Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Roland, C M, E-mail: michal.mierzwa@us.edu.p [Chemistry Division, Naval Research Laboratory, Code 6120, Washington, DC 20375-5342 (United States)

    2010-06-16

    The dynamics of isooctylcyanobiphenyl (8*OCB) was characterized using dielectric and mechanical spectroscopies. This isomer of the liquid crystalline octylcyanobiphenyl (8OCB) vitrifies during cooling or on application of pressure, exhibiting the typical features of glass-forming liquids: non-Debye relaxation function, non-Arrhenius temperature dependence of the relaxation times, {tau}{sub {alpha}}, a dynamic crossover at T {approx} 1.6T{sub g}. This crossover is evidenced by changes in the behavior of both the peak shape and the temperature dependence of {tau}{sub {alpha}}. The primary relaxation time at the crossover, 2 ns at ambient pressure, is the smallest value reported to date for any molecular liquid or polymer. Interestingly, at all temperatures below this crossover, {tau}{sub {alpha}}and the dc conductivity remain coupled (i.e., conform to the Debye-Stokes-Einstein relation). Two secondary relaxations are observed in the glassy state, one of which is identified as the Johari-Goldstein process. Unlike the case for 8OCB, no liquid crystalline phase could be attained for 8*OCB, demonstrating that relatively small differences in chemical structure can effect substantial changes in the intermolecular potential.

  3. Magnetic Resonance Fingerprinting with short relaxation intervals.

    Science.gov (United States)

    Amthor, Thomas; Doneva, Mariya; Koken, Peter; Sommer, Karsten; Meineke, Jakob; Börnert, Peter

    2017-09-01

    The aim of this study was to investigate a technique for improving the performance of Magnetic Resonance Fingerprinting (MRF) in repetitive sampling schemes, in particular for 3D MRF acquisition, by shortening relaxation intervals between MRF pulse train repetitions. A calculation method for MRF dictionaries adapted to short relaxation intervals and non-relaxed initial spin states is presented, based on the concept of stationary fingerprints. The method is applicable to many different k-space sampling schemes in 2D and 3D. For accuracy analysis, T 1 and T 2 values of a phantom are determined by single-slice Cartesian MRF for different relaxation intervals and are compared with quantitative reference measurements. The relevance of slice profile effects is also investigated in this case. To further illustrate the capabilities of the method, an application to in-vivo spiral 3D MRF measurements is demonstrated. The proposed computation method enables accurate parameter estimation even for the shortest relaxation intervals, as investigated for different sampling patterns in 2D and 3D. In 2D Cartesian measurements, we achieved a scan acceleration of more than a factor of two, while maintaining acceptable accuracy: The largest T 1 values of a sample set deviated from their reference values by 0.3% (longest relaxation interval) and 2.4% (shortest relaxation interval). The largest T 2 values showed systematic deviations of up to 10% for all relaxation intervals, which is discussed. The influence of slice profile effects for multislice acquisition is shown to become increasingly relevant for short relaxation intervals. In 3D spiral measurements, a scan time reduction of 36% was achieved, maintaining the quality of in-vivo T1 and T2 maps. Reducing the relaxation interval between MRF sequence repetitions using stationary fingerprint dictionaries is a feasible method to improve the scan efficiency of MRF sequences. The method enables fast implementations of 3D spatially

  4. Production of Seamless Superconducting Radio Frequency Cavities from Ultra-fine Grained Niobium, Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Roy Crooks, Ph.D., P.E.

    2009-10-31

    The positron and electron linacs of the International Linear Collider (ILC) will require over 14,000, nine-cell, one meter length, superconducting radio frequency (SRF) cavities [ILC Reference Design Report, 2007]. Manufacturing on this scale will benefit from more efficient fabrication methods. The current methods of fabricating SRF cavities involve deep drawing of the halves of each of the elliptical cells and joining them by high-vacuum, electron beam welding, with at least 19 circumferential welds per cavity. The welding is costly and has undesirable effects on the cavity surfaces, including grain-scale surface roughening at the weld seams. Hydroforming of seamless tubes avoids welding, but hydroforming of coarse-grained seamless tubes results in strain-induced surface roughening. Surface roughness limits accelerating fields, because asperities prematurely exceed the critical magnetic field and become normal conducting. This project explored the technical and economic feasibility of an improved processing method for seamless tubes for hydroforming. Severe deformation of bulk material was first used to produce a fine structure, followed by extrusion and flow-forming methods of tube making. Extrusion of the randomly oriented, fine-grained bulk material proceeded under largely steady-state conditions, and resulted in a uniform structure, which was found to be finer and more crystallographically random than standard (high purity) RRR niobium sheet metal. A 165 mm diameter billet of RRR grade niobium was processed into five, 150 mm I.D. tubes, each over 1.8 m in length, to meet the dimensions used by the DESY ILC hydroforming machine. Mechanical properties met specifications. Costs of prototype tube production were approximately twice the price of RRR niobium sheet, and are expected to be comparable with economies of scale. Hydroforming and superconducting testing will be pursued in subsequent collaborations with DESY and Fermilab. SRF Cavities are used to construct

  5. Corroborative evidences of TV γ -scaling of the α-relaxation originating from the primitive relaxation/JG β relaxation

    Science.gov (United States)

    Ngai, K. L.; Paluch, M.

    2017-12-01

    Successful thermodynamic scaling of the structural alpha-relaxation time or transport coefficients of glass-forming liquids determined at various temperatures T and pressures P means the data conform to a single function of the product variable TVgamma, where V is the specific volume and gamma is a material specific constant. In the past two decades we have witnessed successful TVgamma-scaling in many molecular, polymeric, and even metallic glass-formers, and gamma is related to the slope of the repulsive part of the intermolecular potential. The advances made indicate TVgamma-scaling is an important aspect of the dynamic and thermodynamic properties of glass-formers. In this paper we show the origin of TVgamma-scaling is not from the structural alpha-relaxation time. Instead it comes from its precursor, the Johari-Goldstein beta-relaxation or the primitive relaxation of the Coupling Model and their relaxation times or tau_0 respectively. It is remarkable that all relaxation times are functions of TVgamma with the same gama, as well as the fractional exponent of the Kohlrausch correlation function of the structural alpha-relaxation. We arrive at this conclusion convincingly based on corroborative evidences from a number of experiments and molecular dynamics simulations performed on a wide variety of glass-formers and in conjunction with consistency with the predictions of the Coupling Model.

  6. Switching Characteristics and High-Temperature Dielectric Relaxation Behaviours of Pb(Zn1/3Nb2/3)0.91Ti0.09O₃ Single Crystal.

    Science.gov (United States)

    Zhu, Zhi; Tang, Xingui; Jiang, Yanping; Liu, Qiuxiang; Zhang, Tianfu; Li, Wenhua

    2017-03-28

    This work evaluated the resistance switching characteristics in the (100)-oriented Pb(Zn 1/3 Nb 2/3 ) 0.91 Ti 0.09 O₃ (PZNT) single crystal. The current hysteresis can be closely related to the ferroelectric polarization and we provided a possible explanation using a model about oxygen vacancies to analyze the mechanism of switching. The obvious frequency dispersion of the relative permittivity signified the relaxer-type behavior of the sample. The value of the relaxation parameter γ = 1.48 was estimated from the linear fit of the modified Curie-Weiss law, indicating the relaxer nature. High-temperature dielectric relaxation behaviors were revealed in the temperature region of 400-650 °C. In addition, under the measuring frequency of 10 kHz, ε r was tunable by changing the electric field and the largest tunability of ε r reached 14.78%. At room temperature, the high pyroelectric coefficient and detectivity figure of merit were reported.

  7. Relaxing a large cosmological constant

    International Nuclear Information System (INIS)

    Bauer, Florian; Sola, Joan; Stefancic, Hrvoje

    2009-01-01

    The cosmological constant (CC) problem is the biggest enigma of theoretical physics ever. In recent times, it has been rephrased as the dark energy (DE) problem in order to encompass a wider spectrum of possibilities. It is, in any case, a polyhedric puzzle with many faces, including the cosmic coincidence problem, i.e. why the density of matter ρ m is presently so close to the CC density ρ Λ . However, the oldest, toughest and most intriguing face of this polyhedron is the big CC problem, namely why the measured value of ρ Λ at present is so small as compared to any typical density scale existing in high energy physics, especially taking into account the many phase transitions that our Universe has undergone since the early times, including inflation. In this Letter, we propose to extend the field equations of General Relativity by including a class of invariant terms that automatically relax the value of the CC irrespective of the initial size of the vacuum energy in the early epochs. We show that, at late times, the Universe enters an eternal de Sitter stage mimicking a tiny positive cosmological constant. Thus, these models could be able to solve the big CC problem without fine-tuning and have also a bearing on the cosmic coincidence problem. Remarkably, they mimic the ΛCDM model to a large extent, but they still leave some characteristic imprints that should be testable in the next generation of experiments.

  8. The effects of progressive muscle relaxation and autogenic relaxation on young soccer players' mood states.

    Science.gov (United States)

    Hashim, Hairul Anuar; Hanafi Ahmad Yusof, Hazwani

    2011-06-01

    This study was designed to compare the effects of two different relaxation techniques, namely progressive muscle relaxation (PMR) and autogenic relaxation (AGR) on moods of young soccer players. sixteen adolescent athletes (mean age: 14.1 ± 1.3) received either PMR or AGR training. Using Profile of Mood States- Adolescents, their mood states were measured one week before relaxation training, before the first relaxation session, and after the twelfth relaxation session. Mixed ANOVA revealed no significant interaction effects and no significant main effects in any of the subscales. However, significant main effects for testing sessions were found for confusion, depression, fatigue, and tension subscales. Post hoc tests revealed post-intervention reductions in the confusion, depression, fatigue, and tension subscale scores. These two relaxation techniques induce equivalent mood responses and may be used to regulate young soccer players' mood states.

  9. The Effects of Progressive Muscle Relaxation and Autogenic Relaxation on Young Soccer Players’ Mood States

    Science.gov (United States)

    Hashim, Hairul Anuar; Hanafi@Ahmad Yusof, Hazwani

    2011-01-01

    Purpose This study was designed to compare the effects of two different relaxation techniques, namely progressive muscle relaxation (PMR) and autogenic relaxation (AGR) on moods of young soccer players. Methods Sixteen adolescent athletes (mean age: 14.1 ± 1.3) received either PMR or AGR training. Using Profile of Mood States- Adolescents, their mood states were measured one week before relaxation training, before the first relaxation session, and after the twelfth relaxation session. Results Mixed ANOVA revealed no significant interaction effects and no significant main effects in any of the subscales. However, significant main effects for testing sessions were found for confusion, depression, fatigue, and tension subscales. Post hoc tests revealed post-intervention reductions in the confusion, depression, fatigue, and tension subscale scores. Conclusion These two relaxation techniques induce equivalent mood responses and may be used to regulate young soccer players’ mood states. PMID:22375225

  10. Relaxation rates studies in an argon cylindrical plasma

    International Nuclear Information System (INIS)

    Hernandez, M.A.; Dengra, A.; Colomer, V.

    1986-01-01

    The single Langmuir probe method has been used to determine the relaxation rates of the electron density and temperature in an argon afterglow dc cylindrical plasma. The ion-electron recombination was found to be the fundamental mechanism of density decay during the early afterglow while the ambipolar diffusion controlles the density decay for later afterglow. Electron temperature cooling curves have been interpreted via electron-neutral collisons. Measurements of the electron-ion recombination and the ambipolar diffusion coefficients have been made, as well as of the electron-neutral collision frequency and the momentum transfer cross sections. Good agreement is obtained with previously published data. (author)

  11. Memristor-based relaxation oscillators using digital gates

    KAUST Repository

    Khatib, Moustafa A.

    2012-11-01

    This paper presents two memristor-based relaxation oscillators. The proposed oscillators are designed without the need of any reactive elements, i.e., capacitor or inductor. As the \\'resistance storage\\' property of the memristor can be exploited to generate the oscillation. The proposed oscillators have the advantage that they can be fully integrated on-chip giving an area-efficient solution. Furthermore, these oscillators give higher frequency other than the existing reactance-less oscillator and provide a wider range of the resistance. The concept of operation and the mathematical analysis for the proposed oscillators are explained and verified with circuit simulations showing an excellent agreement. © 2012 IEEE.

  12. Spin-lattice relaxation in phosphorescent triplet state molecules

    International Nuclear Information System (INIS)

    Verbeek, P.J.F.

    1979-01-01

    The present thesis contains the results of a study of spin-lattice relaxation (SLR) in the photo-excited triplet state of aromatic molecules, dissolved in a molecular host crystal. It appears that SLR in phosphorescent triplet state molecules often is related to the presence of so-called (pseudo) localized phonons in the molecular mixed crystals. These local phonons can be thought to correspond with vibrations (librations) of the guest molecule in the force field of the surrounding host molecules. Since the intermolecular forces are relatively weak, the frequencies corresponding with these vibrations are relatively low and usually are of the order of 10-30 cm -1 . (Auth.)

  13. Development of corrosion condition sensing and monitoring system using radio-frequency identification devices (RFID) : progress report 2

    Energy Technology Data Exchange (ETDEWEB)

    Gu, G.P.; Li, J.; Liu, P.; Bibby, D.; Zheng, W.; Lo, J. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Materials Technology Laboratory

    2008-12-15

    The development of a corrosion severity monitoring system that used radio-frequency identification device (RIFD) technology was discussed. A corrosion monitoring sensor was integrated with a tag modified to partially block the radio frequency signal. The metallic coating caused a frequency shift of the device's reader antenna in order to allow for the accurate characterization of metal coatings. Communications between the tag and the reader were re-established as the corrosion process gradually deteriorated the coating. The method was tested experimentally with 3 RFID systems using both active and passive tags were assembled. A passive tag was covered in aluminum foil. Results of the experiment showed that the metallic coating interfered with RFID signals. A cold-spray technology was used to coat tags with metal alloys. The surface morphology of the coatings was tested to determine optimum coating parameters. Further studies are being conducted to develop software for the technology. 4 refs., 11 figs.

  14. Curie-type paramagnetic NMR relaxation in the aqueous solution of Ni(II).

    Science.gov (United States)

    Mareš, Jiří; Hanni, Matti; Lantto, Perttu; Lounila, Juhani; Vaara, Juha

    2014-04-21

    Ni(2+)(aq) has been used for many decades as a model system for paramagnetic nuclear magnetic resonance (pNMR) relaxation studies. More recently, its magnetic properties and also nuclear magnetic relaxation rates have been studied computationally. We have calculated electron paramagnetic resonance and NMR parameters using quantum-mechanical (QM) computation of molecular dynamics snapshots, obtained using a polarizable empirical force field. Statistical averages of hyperfine coupling, g- and zero-field splitting tensors, as well as the pNMR shielding terms, are compared to the available experimental and computational data. In accordance with our previous work, the isotropic hyperfine coupling as well as nuclear shielding values agree well with experimental measurements for the (17)O nuclei of water molecules in the first solvation shell of the nickel ion, whereas larger deviations are found for (1)H centers. We report, for the first time, the Curie-type contribution to the pNMR relaxation rate using QM calculations together with Redfield relaxation theory. The Curie relaxation mechanism is analogous to chemical shift anisotropy relaxation, well-known in diamagnetic NMR. Due to the predominance of other types of paramagnetic relaxation mechanisms for this system, it is possible to extract the Curie term only computationally. The Curie mechanism alone would result in around 16 and 20 s(-1) of relaxation rates (R1 and R2 respectively) for the (1)H nuclei of water molecules bonded to the Ni(2+) center, in a magnetic field of 11.7 T. The corresponding (17)O relaxation rates are around 33 and 38 s(-1). We also report the Curie contribution to the relaxation rate for molecules beyond the first solvation shell in a 1 M solution of Ni(2+) in water.

  15. Zinc-induced cardiomyocyte relaxation in a rat model of hyperglycemia is independent of myosin isoform

    Directory of Open Access Journals (Sweden)

    Yi Ting

    2012-11-01

    Full Text Available Abstract It has been reported previously that diabetic cardiomyopathy can be inhibited or reverted with chronic zinc supplementation. In the current study, we hypothesized that total cardiac calcium and zinc content is altered in early onset diabetes mellitus characterized in part as hyperglycemia (HG and that exposure of zinc ion (Zn2+ to isolated cardiomyocytes would enhance contraction-relaxation function in HG more so than in nonHG controls. To better control for differential cardiac myosin isoform expression as occurs in rodents after β-islet cell necrosis, hypothyroidism was induced in 16 rats resulting in 100% β-myosin heavy chain expression in the heart. β-Islet cell necrosis was induced in half of the rats by streptozocin administration. After 6 wks of HG, both HG and nonHG controls rats demonstrated similar myofilament performance measured as thin filament calcium sensitivity, native thin filament velocity in the myosin motility assay and contractile velocity and power. Extracellular Zn2+ reduced cardiomyocyte contractile function in both groups, but enhanced relaxation function significantly in the HG group compared to controls. Most notably, a reduction in diastolic sarcomere length with increasing pacing frequencies, i.e., incomplete relaxation, was more pronounced in the HG compared to controls, but was normalized with extracellular Zn2+ application. This is a novel finding implicating that the detrimental effect of HG on cardiomyocyte Ca2+ regulation can be amelioration by Zn2+. Among the many post-translational modifications examined, only phosphorylation of ryanodine receptor (RyR at S-2808 was significantly higher in HG compared to nonHG. We did not find in our hypothyroid rats any differentiating effects of HG on myofibrillar protein phosphorylation, lysine acetylation, O-linked N-acetylglucosamine and advanced glycated end-products, which are often implicated as complicating factors in cardiac performance due to HG. Our

  16. Composite Analysis of Concrete - Creep, Relaxation and Eigenstrain/stress

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    1996-01-01

    approach.The model is successfully justified comparing predicted results with recent experimental data obtained in tests made at the Danish Technological Institute and at the Technical University of Denmark on creep, relaxation, and shrinkage of very young concretes (hours) - and also with experimental...... results on creep, shrinkage, and internal stresses caused by drying shrinkage reported in the literature on the mechanical behavior of mature concretes.Shrinkage (autogeneous or drying) of mortar and concrete and associated internal stress states are examples of analysis made in this report......A composite-rheological model of concrete is presented by which consistent predictions of creep, relaxation, and internal stresses can be made from known concrete composition, age at loading, and climatic conditions. No other existing "creep prediction method" offers these possibilities in one...

  17. Homogeneous magnetic relaxation in iron-yttrium garnets in the vicinity of a phase transition

    International Nuclear Information System (INIS)

    Luzyanin, I.D.; Khavronin, V.P.

    1977-01-01

    Results are presented of an experimental investigation of the dynamics of homogeneous magnetization during a phase transition of the second kind in iron-yttrium garnet (IYG) single crystals of various shapes. It is shown that homogeneous relaxation significantly depends on both the magnitude of 4πchisub(st) (chisub(st) is static magnetic susceptibility) as well as on the relation between the variable field frequency (at which the investigation is carried out) and the characteristic energies. It is shown that beginning from temperatures such as 4πchisub(st) approximately 1, the characteristic dipole interaction energy becomes frequency dependent; this indicates that in this case Lorentz coupling between the dynamic susceptibility and homogeneous relaxation time is invalid. This is a principle point in investigations of homogeneous relaxation by radio-frequency techniques. The temperature dependence of the homogeneous relaxation time and static susceptibility is determined in the exchange region. It is found that the phase transition in IYG involves anomalous phenomena which manifest in release and absorption of heat by a sample and in the appearance of additional singularities in the temperature dependence of the homogeneous relaxation time

  18. Excitations and relaxation dynamics in multiferroic GeV4S8 studied by terahertz and dielectric spectroscopy

    Science.gov (United States)

    Reschke, S.; Wang, Zhe; Mayr, F.; Ruff, E.; Lunkenheimer, P.; Tsurkan, V.; Loidl, A.

    2017-10-01

    We report on THz time-domain spectroscopy on multiferroic GeV4S8 , which undergoes orbital ordering at a Jahn-Teller transition at 30.5 K and exhibits antiferromagnetic order below 14.6 K. The THz experiments are complemented by dielectric experiments at audio and radio frequencies. We identify a low-lying excitation close to 0.5 THz, which is only weakly temperature dependent and probably corresponds to a molecular excitation within the electronic level scheme of the V4 clusters. In addition, we detect complex temperature-dependent behavior of a low-lying phononic excitation, closely linked to the onset of orbitally driven ferroelectricity. In the high-temperature cubic phase, which is paramagnetic and orbitally disordered, this excitation is of relaxational character becomes an overdamped Lorentzian mode in the orbitally ordered phase below the Jahn-Teller transition, and finally appears as well-defined phonon excitation in the antiferromagnetic state. Abrupt changes in the real and imaginary parts of the complex dielectric permittivity show that orbital ordering appears via a structural phase transition with strong first-order character and that the onset of antiferromagnetic order is accompanied by significant structural changes, which are of first-order character, too. Dielectric spectroscopy documents that at low frequencies, significant dipolar relaxations are present in the orbitally ordered, paramagnetic phase only. In contrast to the closely related GaV4S8 , this relaxation dynamics that most likely mirrors coupled orbital and polar fluctuations does not seem to be related to the dynamic processes detected in the THz regime.

  19. Longitudinal Surveys of Australian Youth (LSAY) 2009 Cohort: Wave 2 (2010)--Frequency Tables. Technical Report 71B

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2012

    2012-01-01

    The Longitudinal Surveys of Australian Youth (LSAY) program studies the progress of several groups of young Australians as they move from school into post-secondary education and work. This technical paper contains the frequency tables for the LSAY 2009 cohort Wave 2 (2010) data set.

  20. Longitudinal Surveys of Australian Youth (LSAY) 1998 Cohort: Wave 12 (2009)--Frequency Tables. Technical Report 58B

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2010

    2010-01-01

    The Longitudinal Surveys of Australian Youth (LSAY) program studies the progress of several groups of young Australians as they move from school into post-secondary education and work. This technical paper contains the frequency tables for the LSAY 1998 cohort Wave 12 (2009) data set. [For the accompanying questionnaire, "Longitudinal Surveys…

  1. Longitudinal Surveys of Australian Youth (LSAY) 2006 Cohort: Wave 6 (2011)--Frequency Tables. Technical Report 75B

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2012

    2012-01-01

    The Longitudinal Surveys of Australian Youth (LSAY) program studies the progress of several groups of young Australians as they move from school into post-secondary education and work. This series of documents provides supporting information for the LSAY data set of the 2006 cohort at wave 6 (2011). This document presents the frequency tables for…

  2. Longitudinal Surveys of Australian Youth (LSAY): 2006 Cohort Wave 4 (2009)--Frequency Tables. Technical Report 56B

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2010

    2010-01-01

    The Longitudinal Surveys of Australian Youth (LSAY) program studies the progress of several groups of young Australians as they move from school into post-secondary education and work. This technical paper contains the frequency tables for the LSAY 2006 cohort Wave 4 (2009) data set. [For the "Longitudinal Surveys of Australian Youth (LSAY):…

  3. [Central muscle relaxant activities of 2-methyl-3-aminopropiophenone derivatives].

    Science.gov (United States)

    Kontani, H; Mano, A; Koshiura, R; Yamazaki, M; Shimada, Y; Oshita, M; Morikawa, K; Kato, H; Ito, Y

    1987-02-01

    In this experiment, we synthetized new 2-methyl-3-aminopropiophenone (MP) derivatives, whose structure is known to have central muscle relaxant activities, and quinolizidine and indan . tetralin derivatives derived from MP by cyclization, and we investigated the central muscle relaxant activity. Among the quinolizidine derivatives, there was a very strong central depressant agent, trans (3H, 9aH)-3-(p-chloro) benzoyl-quinolizidine (HSR-740), and among the indan . tetralin derivatives, there was an excitant agents, trans (1H, 2H)-5-methoxy-3, 3-dimethyl-2-piperidinomethyl indan-1-ol (HSR-719). From the results, these derivatives were not considered to be adequate for central muscle relaxant. Among the MP derivatives, (4'-chloro-2'-methoxy-3-piperidino) propiophenone HCl (HSR-733) and (4'-ethyl-2-methyl-3-pyrrolidino) propiophenone HCl (HSR-770) strongly inhibited the cooperative movement in the rotating rod method using mice, and it exerted almost the same depressant activity on the cross extensor reflex using alpha-chloralose anesthetized rats. However, the inhibitory effects of HSR-733 on the anemic decerebrate rigidity and the rigidity induced by intracollicular decerebration in rats were weaker than those of HSR-770 and eperisone. In spinal cats, at a low dose (5 mg/kg, i.v.), HSR-733 depressed monosynaptic and dorsal root reflex potentials as compared with polysynaptic reflex potentials, and inhibitory effects of HSR-733 on these three reflex potentials were more potent than those of eperisone and HSR-770. Although HSR-770 acts on the spinal cord and supraspinal level on which eperisone has been reported to act, HSR-733 may mainly act on the spinal cord. These results indicate that the MP derivative with a 2-methyl group may be suitable as a central muscle relaxant. HSR-770, which has equipotent muscle relaxant activity to eperisone, exerted strong inhibitory effects on oxotremorine-induced tremor and weak inhibitory effects on spontaneous motor activity in the

  4. Relaxation Dynamics of Nanoparticle-Tethered Polymer Chains

    KAUST Repository

    Kim, Sung A

    2015-09-08

    © 2015 American Chemical Society. Relaxation dynamics of nanoparticle-tethered cis-1,4-polyisoprene (PI) are investigated using dielectric spectroscopy and rheometry. A model system composed of polymer chains densely grafted to spherical SiO2 nanoparticles to form self-suspended suspensions facilitates detailed studies of slow global chain and fast segmental mode dynamics under surface and geometrical confinement-from experiments performed in bulk materials. We report that unentangled polymer molecules tethered to nanoparticles relax far more slowly than their tethered entangled counterparts. Specifically, at fixed grafting density we find, counterintuitively, that increasing the tethered polymer molecular weight up to values close to the entanglement molecular weight speeds up chain relaxation dynamics. Decreasing the polymer grafting density for a fixed molecular weight has the opposite effect: it dramatically slows down chain relaxation, increases interchain coupling, and leads to a transition in rheological response from simple fluid behavior to viscoelastic fluid behavior for tethered PI chains that are unentangled by conventional measures. Increasing the measurement temperature produces an even stronger elastic response and speeds up molecular relaxation at a rate that decreases with grafting density and molecular weight. These observations are discussed in terms of chain confinement driven by crowding between particles and by the existence of an entropic attractive force produced by the space-filling constraint on individual chains in a self-suspended material. Our results indicate that the entropic force between densely grafted polymer molecules couples motions of individual chains in an analogous manner to reversible cross-links in associating polymers.

  5. Stress relaxation study of water atomized Cu-Cr-Zr powder alloys consolidated by inverse warm extrusion

    International Nuclear Information System (INIS)

    Poblano-Salas, C.A.; Barceinas-Sanchez, J.D.O.

    2009-01-01

    Stress relaxation testing in compression at high temperature was performed on Cu-Cr-Zr alloys produced by consolidation of water atomized powders. Precipitation and recrystallization were monitored during stress relaxation experiments carried out at an ageing temperature of 723 K. Pre-straining imposed to the Cu-Cr-Zr samples prior to stress relaxation testing resulted in reduced hardness compared to that reported for conventionally-aged alloys; it also resulted in shorter times for achieving maximum strengthening on ageing.

  6. Associations between the self-reported frequency of hearing chemical alarms in theater and regional brain volume in Gulf War Veterans.

    Science.gov (United States)

    Chao, Linda L; Reeb, Rosemary; Esparza, Iva L; Abadjian, Linda R

    2016-03-01

    We previously reported evidence of reduced cortical gray matter (GM), white matter (WM), and hippocampal volume in Gulf War (GW) veterans with predicted exposure to low-levels of nerve agent according to the 2000 Khamisiyah plume model analysis. Because there is suggestive evidence that other nerve agent exposures may have occurred during the Gulf War, we examined the association between the self-reported frequency of hearing chemical alarms sound during deployment in the Gulf War and regional brain volume in GW veterans. Ninety consecutive GW veterans (15 female, mean age: 52±8years) participating in a VA-funded study underwent structural magnetic resonance imaging (MRI) on a 3T scanner. Freesurfer (version 5.1) was used to obtain regional measures of cortical GM, WM, hippocampal, and insula volume. Multiple linear regression was used to determine the association between the self-reported frequencies of hearing chemical alarms during the Gulf War and regional brain volume. There was an inverse association between the self-reported frequency of hearing chemical alarms sound and total cortical GM (adjusted p=0.007), even after accounting for potentially confounding demographic and clinical variables, the veterans' current health status, and other concurrent deployment-related exposures that were correlated with hearing chemical alarms. Post-hoc analyses extended the inverse relationship between the frequency of hearing chemical alarms to GM volume in the frontal (adjusted p=0.02), parietal (adjusted p=0.01), and occipital (adjusted p=0.001) lobes. In contrast, regional brain volumes were not significantly associated with predicted exposure to the Khamisiyah plume or with Gulf War Illness status defined by the Kansas or Centers for Disease Control and Prevention criteria. Many veterans reported hearing chemical alarms sound during the Gulf War. The current findings suggest that exposure to substances that triggered those chemical alarms during the Gulf War likely

  7. Strengthening and stress relaxation of Opalinus Clay

    International Nuclear Information System (INIS)

    Schulze, Otto

    2010-01-01

    Document available in extended abstract form only. Full text follows: In the framework of the EU-project NF-PRO (e.g. RTDC-5, Synthesis Report, D-No 5.2.3), special emphasis was put on the investigation and modelling of near-field processes in a candidate host rock: http://project.nf-pro.org/workspaces/rtdc5/deliverables/d5_2_3_rtdc_5_synthesis_report_final_version. The coupled TMHC-processes under consideration mainly concern the interaction between the host rock in and near to the EDZ and the waste products in its immediate vicinity. With respect to long-term safety analyses, there is no doubt that a sound process understanding is required. However, safe disposal also requires a suitable multi-barrier-system. This has to consist of technical and geo-technical barriers (e.g. container and backfill) but also of a strong geological barrier. Comparing the self-sealing capacity of the candidate host rocks, i.e. salt, clay and crystalline rock formations, where underground rooms will be inevitably backfilled only in part for technical reasons, in a salt formation convergence by viscous deformation provokes the re-establishing of a tight system, whereas in a crystalline rock formation long-term isolation has to be guaranteed solely by the technical and geotechnical components. This work is concentrated on the question, whether convergence and reduction of open space by long-term creep will take place also in a clay-stone formation, where laboratory investigation on Opalinus Clay from the Mont Terri Rock Laboratory was performed for this purpose. Several results from the work on the long-term deformation behaviour of clay-stone exist already. Nevertheless, to the author's knowledge the sound proof of a time-dependent and non-dilatant viscous deformation in the undisturbed far-field of clay-stone is still missing. Results from the rock laboratory at the Mt. Terri site yield hints for an anisotropic state of in-situ stresses, which may continue to exist in the

  8. Relaxation of polarized nuclei in superconducting rhodium

    DEFF Research Database (Denmark)

    Knuuttila, T.A.; Tuoriniemi, J.T.; Lefmann, K.

    2000-01-01

    Nuclear spin lattice relaxation rates were measured in normal and superconducting (sc) rhodium with nuclear polarizations up to p = 0.55. This was sufficient to influence the sc state of Rh, whose T, and B-c, are exceptionally low. Because B-c ... is unchanged, the nuclear spin entropy was fully sustained across the sc transition. The relaxation in the sc state was slower at all temperatures without the coherence enhancement close to T-c. Nonzero nuclear polarization strongly reduced the difference between the relaxation rates in the sc and normal...

  9. Spin relaxation in nanowires by hyperfine coupling

    International Nuclear Information System (INIS)

    Echeverria-Arrondo, C.; Sherman, E.Ya.

    2012-01-01

    Hyperfine interactions establish limits on spin dynamics and relaxation rates in ensembles of semiconductor quantum dots. It is the confinement of electrons which determines nonzero hyperfine coupling and leads to the spin relaxation. As a result, in nanowires one would expect the vanishing of this effect due to extended electron states. However, even for relatively clean wires, disorder plays a crucial role and makes electron localization sufficient to cause spin relaxation on the time scale of the order of 10 ns. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Le Chatelier's principle with multiple relaxation channels

    Science.gov (United States)

    Gilmore, R.; Levine, R. D.

    1986-05-01

    Le Chatelier's principle is discussed within the constrained variational approach to thermodynamics. The formulation is general enough to encompass systems not in thermal (or chemical) equilibrium. Particular attention is given to systems with multiple constraints which can be relaxed. The moderation of the initial perturbation increases as additional constraints are removed. This result is studied in particular when the (coupled) relaxation channels have widely different time scales. A series of inequalities is derived which describes the successive moderation as each successive relaxation channel opens up. These inequalities are interpreted within the metric-geometry representation of thermodynamics.

  11. Universal Mechanism of Spin Relaxation in Solids

    Science.gov (United States)

    Chudnovsky, Eugene

    2006-03-01

    Conventional elastic theory ignores internal local twists and torques. Meantime, spin-lattice relaxation is inherently coupled with local elastic twists through conservation of the total angular momentum (spin + lattice). This coupling gives universal lower bound (free of fitting parameters) on the relaxation of the atomic or molecular spin in a solid [1] and on the relaxation of the electron spin in a quantum dot [2]. [1] E. M. Chudnovsky, D. A. Garanin, and R. Schilling, Phys. Rev. B 72, 094426 (2005). [2] C. Calero, E. M. Chudnovsky, and D. A. Garanin, Phys. Rev. Lett. 95, 166603 (2005).

  12. Collisional relaxation of electron tail distribution

    International Nuclear Information System (INIS)

    Yamagiwa, Mitsuru; Okamoto, Masao.

    1985-05-01

    Relaxation due to the Coulomb collisions of the electron velocity distribution function with a high energy tail is investigated in detail. In the course of the relaxation, a 'saddle' point can be created in velocity space owing to upsilon -3 dependence of the deflection rate and a positive slope or a 'dip' appears in the tail direction. The time evolution of the electron tail is studied analytically. A comparison is made with numerical results by using a Fokker-Planck code. Also discussed is the kinetic instability concerned with the positive slope during the relaxation. (author)

  13. Nuclear magnetic resonance relaxation in multiple sclerosis

    DEFF Research Database (Denmark)

    Larsson, H B; Barker, G J; MacKay, A

    1998-01-01

    OBJECTIVES: The theory of relaxation processes and their measurements are described. An overview is presented of the literature on relaxation time measurements in the normal and the developing brain, in experimental diseases in animals, and in patients with multiple sclerosis. RESULTS...... AND CONCLUSION: Relaxation time measurements provide insight into development of multiple sclerosis plaques, especially the occurrence of oedema, demyelination, and gliosis. There is also evidence that normal appearing white matter in patients with multiple sclerosis is affected. What is now needed are fast...

  14. Stress Relaxation in Entangled Polymer Melts

    DEFF Research Database (Denmark)

    Hou, Ji-Xuan; Svaneborg, Carsten; Everaers, Ralf

    2010-01-01

    We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts. The data allow us to explore the chain dynamics and the shear relaxation modulus, G(t), into the plateau regime for chains with Z=40 entanglements...... and into the terminal relaxation regime for Z=10. Using the known (Rouse) mobility of unentangled chains and the melt entanglement length determined via the primitive path analysis of the microscopic topological state of our systems, we have performed parameter-free tests of several different tube models. We find...

  15. Slow relaxation in weakly open rational polygons.

    Science.gov (United States)

    Kokshenev, Valery B; Vicentini, Eduardo

    2003-07-01

    The interplay between the regular (piecewise-linear) and irregular (vertex-angle) boundary effects in nonintegrable rational polygonal billiards (of m equal sides) is discussed. Decay dynamics in polygons (of perimeter P(m) and small opening Delta) is analyzed through the late-time survival probability S(m) approximately equal t(-delta). Two distinct slow relaxation channels are established. The primary universal channel exhibits relaxation of regular sliding orbits, with delta=1. The secondary channel is given by delta>1 and becomes open when m>P(m)/Delta. It originates from vertex order-disorder dual effects and is due to relaxation of chaoticlike excitations.

  16. [A study on Korean concepts of relaxation].

    Science.gov (United States)

    Park, J S

    1992-01-01

    Relaxation technique is an independent nursing intervention used in various stressful situations. The concept of relaxation must be explored for the meaning given by the people in their traditional thought and philosophy. Korean relaxation technique, wanting to become culturally acceptable and effective, is learning to recognize and develop Korean concepts, experiences, and musics of relaxation. This study was aimed at discovering Korean concepts, experiences and musics of relaxation and contributing the development of the relaxation technique for Korean people. The subjects were 59 nursing students, 39 hospitalized patients, 61 housewives, 21 rural residents and 16 researchers. Data were collected from September 4th to October 24th, 1991 by interviews or questionnaires. The data analysis was done by qualitative research method, and validity assured by conformation of the concept and category by 2 nursing scientists who had written a Master's thesis on the relaxation technique. The results of the study were summarized as follows; 1. The meaning of the relaxation concept; From 298 statements, 107 concepts were extracted and then 5 categories "Physical domain", "Psychological domain", "Complex domain", "Situation", and "environment" were organized. 'Don't have discomforts, 'don't have muscle tension', 'don't have energy (him in Korean)', 'don't have activities' subcategories were included in "Physical domain". 'Don't have anxiety', 'feel good', 'emotional stability', 'don't have wordly thoughts', 'feel one's brain muddled', 'loss of desire' subcategories were included in "physical domain" 'Comfort body and mind', 'don't have tension of body and mind', 'be sagged' 'liveliness of thoughts' subcategories were included in "Complex domain". 'Rest', 'sleep', 'others' subcategories were included in "Situation domain". And 'quite environment' & 'comfortable environment' subcategories were included in "Environmental domain". 2. The experiences of the relaxation; From 151

  17. Analysis of vibroprotection characteristics of pneumatic relaxation seat suspension with capability of vibration energy recuperation

    Directory of Open Access Journals (Sweden)

    Lyashenko Mikhail

    2017-01-01

    Full Text Available This paper proposes mechanism and control algorithm for pneumatic relaxation system of suspension with vibration energy recuperation applied to standard vehicle operator seat (“Sibeko” company. Mathematical model of the seat pneumatic relaxation suspension with two additional air volumes was created. Pneumatic motor – recuperator activated by means of air flow from the one additional volume to another is installed in air piping between additional volumes. Computational research was made in Matlab/Simulink. Amplitude-frequency characteristics of transmission coefficient for standard and proposed suspensions were plotted for preliminary evaluation of vibration protection properties of seat suspension. Performed comparative analysis of amplitude-frequency characteristics shows that noticeable improvement of vibration protection properties of pneumatic relaxation suspension system with vibration energy recuperation in comparison with standard system both in region of resonance disturbances and in above-resonance region. Main ways for further improvement of vibration protection properties of proposed system were marked out.

  18. Frequency of self-reported COPD exacerbation and airflow obstruction in five Latin American cities: the Proyecto Latinoamericano de Investigacion en Obstruccion Pulmonar (PLATINO) study.

    Science.gov (United States)

    Montes de Oca, Maria; Tálamo, Carlos; Halbert, Ronald J; Perez-Padilla, Rogelio; Lopez, Maria Victorina; Muiño, Adriana; Jardim, José Roberto B; Valdivia, Gonzalo; Pertuzé, Julio; Moreno, Dolores; Menezes, Ana Maria B

    2009-07-01

    Recurrent exacerbations are common in COPD patients. Limited information exists regarding exacerbation frequency in COPD patients from epidemiologic studies. We examined the frequency of self-reported exacerbations and the factors influencing exacerbation frequency among COPD patients in a population-based study conducted in Latin America. We used a post-bronchodilator FEV(1)/FVC ratio of < 0.70 to define COPD. Exacerbation was self-reported and defined by symptoms (deterioration of breathing symptoms that affected usual daily activities or caused missed work). Spirometry was performed in 5,314 subjects. There were 759 subjects with airflow limitation; of these, 18.2% reported ever having had an exacerbation, 7.9% reported having an exacerbation, and 6.2% reported having an exacerbation requiring at least a doctor visit within the past year. The proportion of individuals with an exacerbation significantly increased by Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages, from 4.2% in stage 1 to 28.9% in stages 3 and 4. The self-reported exacerbation rate was 0.58 exacerbations per year. The rate of exacerbations requiring at least a doctor visit and length of stay in hospital due to exacerbations also increased as COPD severity progressed. The factors associated with having an exacerbation in the past year were dyspnea, prior asthma diagnosis, receiving any respiratory therapy, and disease severity of GOLD stages 3 and 4. The proportion of individuals with airflow limitation and self-reported exacerbation increases as the disease severity progresses. Dyspnea, prior asthma diagnosis, receiving any respiratory therapy, and more severe obstruction were significantly associated with having an exacerbation in the past year.

  19. Vibrational relaxation of a triatomic molecular impurity: D2O in vitreous As2S3

    International Nuclear Information System (INIS)

    Rella, C.W.; Schwettman, H.A.; Engholm, J.R.

    1995-01-01

    Measurements of the relaxation of the D 2 O stretch mode in vitreous As 2 S 3 are presented. Because the bending mode of the molecule offers an intra-molecular decay channel for the stretch mode, the decay scheme of the D 2 O molecule is more complex than that of diatomic molecules. The asymmetric stretch mode of D 2 O has a frequency of 2680 cm -1 . To study the relaxation of this mode we applied a pump-probe technique, using intense psec; pulses of the Stanford Free Electron Laser. Due to the small cross-section of the vibrational mode, successful efforts were made to improve the signal to noise ratio by using a laser stabilization system and a tightly focused beam to increase the intensity, by averaging the signal with a kHz repetition rate and by using samples with an optimized D 2 O concentration. A rapid relaxation rate on the order of 5 x 10 9 sec -1 at low temperature is found that increases with temperature. Recalling that the bending mode of the D 2 O molecule has a frequency of 1170 cm -1 , one would expect a decay in a third order process, involving two quanta of the bending mode plus a vibrational host quanta with a frequency of 340 cm -1 , which coincides with a fundamental frequency of the pyramidal building blocks of the glassy As 2 S 3 host. Instead, we find from the temperature dependence of the relaxation rate that the D 2 O stretching mode relaxes in a higher order process. This indicates that the relaxation dynamics of small molecules is more complex than generally assumed

  20. The association between parents' perceived social norms for toothbrushing and the frequency with which they report brushing their child's teeth.

    Science.gov (United States)

    Trubey, R J; Moore, S C; Chestnutt, I G

    2015-06-01

    To determine whether parents' judgements on how often other parents brush their children's teeth are associated with the frequency with which they brush their own children's teeth, and their satisfaction with their child's brushing routine. A cross-sectional questionnaire survey completed by 297 parents of children aged 3-6. Parents were asked how often they brushed their own child's teeth per week, how often they thought other parents did so, and how satisfied they were with their child's toothbrushing routine. Demographic data were also collected. The mean frequency that parents brushed their children's teeth was 12.5 times per week. Multiple regression analysis tested the relationship between parents' perceptions of other parents brushing frequency (mean 10.5 times per week) and how often they brushed their own child's teeth, controlling for socio-demographic factors, and yielded a positive association (p parents' satisfaction with their child's brushing routine and the extent to which they thought it was better than that of the average child (p Parents' judgements on how frequently other parents brush their children's teeth are associated with their own behaviour and satisfaction. Re-framing oral health messages to include some form of social normative information ("most parents do this") may prove more persuasive than simple prescriptive advice ("you should do this").

  1. Relaxation processes during amorphous metal alloys heating

    International Nuclear Information System (INIS)

    Malinochka, E.Ya.; Durachenko, A.M.; Borisov, V.T.

    1982-01-01

    Behaviour of Te+15 at.%Ge and Fe+13 at.%P+7 at.%C amorphous metal alloys during heating has been studied using the method of differential scanning calorimetry (DSC) as the most convenient one for determination of the value of heat effects, activation energies, temperature ranges of relaxation processes. Thermal effects corresponding to high-temperature relaxation processes taking place during amorphous metal alloys (AMA) heating are detected. The change of ratio of relaxation peaks values on DSC curves as a result of AMA heat treatment can be explained by the presence of a number of levels of inner energy in amorphous system, separated with potential barriers, the heights of which correspond to certain activation energies of relaxation processes

  2. The relaxation of plasmas with dust particles

    International Nuclear Information System (INIS)

    Chutov, Yu.I.; Kravchenko, A.Yu.; Schram, P.P.J.M.

    1997-01-01

    Various parameters of relaxing plasmas with dust particles including the electron and ion energy distributions function are numerically simulated at various parameters of the dust particles using the PIC method and taking into account the dynamics of the dust particle charge without the assumption about the equilibrium of electrons and ions. Coulomb collisions are taken into account in the framework of the method of stochastic differential equations. The relaxation of bounded plasma clouds expanding into a vacuum as well as the relaxation of a uniform plasma, in which dust particles appear at some initial time, are investigated. The obtained results show that the relaxation of plasmas can be accompanied by a deviation of the ion distribution function from equilibrium as well as a change of the mean energy of electrons and ions because of the dependence of the collection of electrons and ions by dust particles on their energy. (author)

  3. Multiscale dipole relaxation in dielectric materials

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt

    2016-01-01

    Dipole relaxation from thermally induced perturbations is investigated on different length scales for dielectric materials. From the continuum dynamical equations for the polarisation, expressions for the transverse and longitudinal dipole autocorrelation functions are derived in the limit where ...

  4. Generalized approach to non-exponential relaxation

    Indian Academy of Sciences (India)

    Non-exponential relaxation is a universal feature of systems as diverse as glasses, spin ... which changes from a simple exponential to a stretched exponential and a power law by increasing the constraints in the system. ... Current Issue

  5. Oxygen-17 relaxation in aqueous agarose gels

    International Nuclear Information System (INIS)

    Ablett, S.; Lillford, P.J.

    1977-01-01

    Nuclear magnetic relaxation of oxygen-17 in H 2 17 O enriched agarose gels shows that existing explanations of water behaviour are oversimplified. Satisfactory models must include at least three proton phases, two of which involve water molecules. (Auth.)

  6. Suppression of Electron Spin Relaxation in Mn-Doped GaAs

    Science.gov (United States)

    Astakhov, G. V.; Dzhioev, R. I.; Kavokin, K. V.; Korenev, V. L.; Lazarev, M. V.; Tkachuk, M. N.; Kusrayev, Yu. G.; Kiessling, T.; Ossau, W.; Molenkamp, L. W.

    2008-08-01

    We report a surprisingly long spin relaxation time of electrons in Mn-doped p-GaAs. The spin relaxation time scales with the optical pumping and increases from 12 ns in the dark to 160 ns upon saturation. This behavior is associated with the difference in spin relaxation rates of electrons precessing in the fluctuating fields of ionized or neutral Mn acceptors, respectively. For the latter, the antiferromagnetic exchange interaction between a Mn ion and a bound hole results in a partial compensation of these fluctuating fields, leading to the enhanced spin memory.

  7. Relaxation and hypnosis in pediatric dental patients.

    Science.gov (United States)

    Peretz, B

    1996-01-01

    Relaxation and hypnosis are methods which, may solve the problem of extreme dental anxiety, when all other methods, behavioral or pharmacological may not be used. A simple definition of hypnosis is suggestion and repetition. Suggestion is the process whereby an individual accepts a proposition put to him by another, without having the slightest logical reason for doing so. Relaxation is one method of inducing hypnosis. A case of using hypnosis on an 11-year-old boy is described.

  8. Ghost lines in Moessbauer relaxation spectra

    International Nuclear Information System (INIS)

    Price, D.C.

    1985-01-01

    The appearance in Moessbauer relaxation spectra of 'ghost' lines, which are narrow lines that do not correspond to transitions between real hyperfine energy levels of the resonant system, is examined. It is shown that in many cases of interest, the appearance of these 'ghost' lines can be interpreted in terms of the relaxational averaging of one or more of the static interactions of the ion. (orig.)

  9. Dynamics of helicity transport and Taylor relaxation

    International Nuclear Information System (INIS)

    Diamond, P.H.; Malkov, M.

    2003-01-01

    A simple model of the dynamics of Taylor relaxation is derived using symmetry principles alone. No statistical closure approximations are invoked or detailed plasma model properties assumed. Notably, the model predicts several classes of nondiffusive helicity transport phenomena, including traveling nonlinear waves and superdiffusive turbulent pulses. A universal expression for the scaling of the effective magnetic Reynolds number of a system undergoing Taylor relaxation is derived. Some basic properties of intermittency in helicity transport are examined

  10. Regularities of intermediate adsorption complex relaxation

    International Nuclear Information System (INIS)

    Manukova, L.A.

    1982-01-01

    The experimental data, characterizing the regularities of intermediate adsorption complex relaxation in the polycrystalline Mo-N 2 system at 77 K are given. The method of molecular beam has been used in the investigation. The analytical expressions of change regularity in the relaxation process of full and specific rates - of transition from intermediate state into ''non-reversible'', of desorption into the gas phase and accumUlation of the particles in the intermediate state are obtained

  11. Frequency and analysis of non-clinical errors made in radiology reports using the National Integrated Medical Imaging System voice recognition dictation software.

    Science.gov (United States)

    Motyer, R E; Liddy, S; Torreggiani, W C; Buckley, O

    2016-11-01

    Voice recognition (VR) dictation of radiology reports has become the mainstay of reporting in many institutions worldwide. Despite benefit, such software is not without limitations, and transcription errors have been widely reported. Evaluate the frequency and nature of non-clinical transcription error using VR dictation software. Retrospective audit of 378 finalised radiology reports. Errors were counted and categorised by significance, error type and sub-type. Data regarding imaging modality, report length and dictation time was collected. 67 (17.72 %) reports contained ≥1 errors, with 7 (1.85 %) containing 'significant' and 9 (2.38 %) containing 'very significant' errors. A total of 90 errors were identified from the 378 reports analysed, with 74 (82.22 %) classified as 'insignificant', 7 (7.78 %) as 'significant', 9 (10 %) as 'very significant'. 68 (75.56 %) errors were 'spelling and grammar', 20 (22.22 %) 'missense' and 2 (2.22 %) 'nonsense'. 'Punctuation' error was most common sub-type, accounting for 27 errors (30 %). Complex imaging modalities had higher error rates per report and sentence. Computed tomography contained 0.040 errors per sentence compared to plain film with 0.030. Longer reports had a higher error rate, with reports >25 sentences containing an average of 1.23 errors per report compared to 0-5 sentences containing 0.09. These findings highlight the limitations of VR dictation software. While most error was deemed insignificant, there were occurrences of error with potential to alter report interpretation and patient management. Longer reports and reports on more complex imaging had higher error rates and this should be taken into account by the reporting radiologist.

  12. Ultrasonic relaxation studies associated with n-octylamine-heavy water

    International Nuclear Information System (INIS)

    Kor, S.K.; Singh, R.K.

    1994-01-01

    Ultrasonic absorption measurements have been carried out in lyotropic liquid crystalline system n-octylamine/heavy water in the frequency range 5-65 MHz and at temperatures 30 degC and 37 degC at different concentrations of heavy water in octylamine. Velocity has been measured using interferometric technique at 2 MHz at different concentrations of heavy water. Ultrasonic absorption coefficients at different concentrations in the concentration range 0.3-0.9 m.f. heavy water have been found to show a maxima in the absorption curve at critical concentration (∼0.85 m.f. heavy water). This peak has been found to shift towards lower concentrations of heavy water at higher frequencies. Results have been analysed and it has been found that single relaxation process takes place around 30 MHz and this has been attributed to aggregation of octylamine and heavy water molecules. (author). 8 refs., 6 figs., 3 tabs

  13. Dielectric relaxation studies in 5CB nematic liquid crystal at 9 GHz ...

    Indian Academy of Sciences (India)

    Resonance width, shift in resonance frequency, relaxation time and activation energy of 5CB nematic liquid crystal are measured using microwave cavity technique under the influence of an external magnetic field at 9 GHz and at different temperatures. The dielectric response in liquid crystal at different temperatures and ...

  14. Prolonged-Release Oxycodone/Naloxone Improves Anal Sphincter Relaxation Compared to Oxycodone Plus Macrogol 3350

    DEFF Research Database (Denmark)

    Poulsen, Jakob Lykke; Brock, Christina; Grønlund, Debbie

    2017-01-01

    /naloxone or PR oxycodone plus macrogol 3350. Resting anal pressure, anal canal distensibility, and relaxation of the internal sphincter to rectal distension were evaluated before treatment (baseline) and on day 5. The Patient Assessment of Constipation Symptom (PAC-SYM) questionnaire, stool frequency, and stool...

  15. On-chip Brownian relaxation measurements of magnetic nanobeads in the time domain

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Rizzi, Giovanni; Hansen, Mikkel Fougt

    2013-01-01

    the time and frequency domain methods on Brownian relaxation detection of clustering of streptavidin coated magnetic beads in the presence of different concentrations of biotin-conjugated bovine serum albumin and obtain comparable results. In the time domain, a measurement is carried out in less than 30 s...

  16. Three-axial force sensor with capacitive read-out using a differential relaxation oscillator

    NARCIS (Netherlands)

    Brookhuis, Robert Anton; Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Krijnen, Gijsbertus J.M.

    2013-01-01

    A silicon three-axis force sensor is designed and realized to be used for measurement of the interaction force between a human finger and the environment. To detect the force components, a capacitive read-out system using a novel relaxation oscillator has been developed with an output frequency

  17. Macroscopic theory of the relaxation of collective excitations in disordered and noncollinear magnets

    International Nuclear Information System (INIS)

    Bar'yakhtar, V.G.; Belykh, V.G.; Soboleva, T.K.

    1989-01-01

    In the framework of the general hydrodynamic approach a method is proposed for describing the relaxation of low-frequency magnetic excitations in disordered spin systems and many-sublattice magnets. Expressions are obtained in terms of Goldstone fields for the dissipation function both in the exchange approximation and when allowance is made for relativistic interactions

  18. Transient lower esophageal sphincter relaxation and esophageal motor response.

    Science.gov (United States)

    Schneider, Joachim H; Küper, Markus A; Königsrainer, Alfred; Brücher, Björn L D M

    2010-04-01

    Gastroesophageal reflux is caused by transient lower esophageal sphincter relaxations (TLESRs) in healthy individuals and in most patients with gastroesophageal reflux disease (GERD). Refluxate is normally propelled by pharyngeally induced swallowing events, but TLESRs may also be accompanied by retrograde esophageal motor responses (EMRs). These contractions have not previously been investigated and their effect on esophageal clearance is not known. The aim of this study was to assess the frequency of EMRs after TLESR in healthy individuals and GERD patients and to develop an animal model for further investigation of EMRs. The frequency of TLESRs and esophageal body contractions after TLESRs was assessed using ambulatory manometry in five healthy individuals and five GERD patients. An animal model was developed for reproducible provocation of TLESRs and subsequent EMRs. Patients with GERD have significantly more TLESRs than healthy individuals. However, post-TLESR EMRs were not more frequent in the GERD group. All post-TLESR EMRs presented as simultaneous contractions of the esophagus. The feline model allowed reproducible initiation of the esophageal motor response after TLESR, showing that EMRs can be induced by external mechanoreceptor stimulation simultaneously with LES relaxation. This experimental design imitates the conditions after fundoplication in humans. The study demonstrated that GERD patients have significantly more TLESRs in comparison with healthy individuals, but these were only incidental to EMRs. Further research is needed to improve our understanding of esophageal motility disorders. The animal model presented offers a feasible tool for investigating TLESR-induced esophageal motility.

  19. Relaxation of synchronization on complex networks.

    Science.gov (United States)

    Son, Seung-Woo; Jeong, Hawoong; Hong, Hyunsuk

    2008-07-01

    We study collective synchronization in a large number of coupled oscillators on various complex networks. In particular, we focus on the relaxation dynamics of the synchronization, which is important from the viewpoint of information transfer or the dynamics of system recovery from a perturbation. We measure the relaxation time tau that is required to establish global synchronization by varying the structural properties of the networks. It is found that the relaxation time in a strong-coupling regime (K>Kc) logarithmically increases with network size N , which is attributed to the initial random phase fluctuation given by O(N-1/2) . After elimination of the initial-phase fluctuation, the relaxation time is found to be independent of the system size; this implies that the local interaction that depends on the structural connectivity is irrelevant in the relaxation dynamics of the synchronization in the strong-coupling regime. The relaxation dynamics is analytically derived in a form independent of the system size, and it exhibits good consistency with numerical simulations. As an application, we also explore the recovery dynamics of the oscillators when perturbations enter the system.

  20. Relaxation strain measurements in cellular dislocation structures

    International Nuclear Information System (INIS)

    Tsai, C.Y.; Quesnel, D.J.

    1984-01-01

    The conventional picture of what happens during a stress relaxation usually involves imagining the response of a single dislocation to a steadily decreasing stress. The velocity of this dislocation decreases with decreasing stress in such a way that we can measure the stress dependence of the dislocation velocity. Analysis of the data from a different viewpoint enables us to calculate the apparent activation volume for the motion of the dislocation under the assumption of thermally activated glie. Conventional thinking about stress relaxation, however, does not consider the eventual fate of this dislocation. If the stress relaxes to a low enough level, it is clear that the dislocation must stop. This is consistent with the idea that we can determine the stress dependence of the dislocation velocity from relaxation data only for those cases where the dislocation's velocity is allowed to approach zero asymptotically, in short, for those cases where the dislocation never stops. This conflict poses a dilemma for the experimentalist. In real crystals, however, obstacles impede the dislocation's progress so that those dislocations which are stopped at a given stress will probably never resume motion under the influence of the steadily declining stress present during relaxation. Thus one could envision stress relaxation as a process of exhaustion of mobile dislocations, rather than a process of decreasing dislocation velocity. Clearly both points of view have merit and in reality both mechanisms contribute to the phenomena

  1. Methods for peak-flow frequency analysis and reporting for streamgages in or near Montana based on data through water year 2015

    Science.gov (United States)

    Sando, Steven K.; McCarthy, Peter M.

    2018-05-10

    This report documents the methods for peak-flow frequency (hereinafter “frequency”) analysis and reporting for streamgages in and near Montana following implementation of the Bulletin 17C guidelines. The methods are used to provide estimates of peak-flow quantiles for 50-, 42.9-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities for selected streamgages operated by the U.S. Geological Survey Wyoming-Montana Water Science Center (WY–MT WSC). These annual exceedance probabilities correspond to 2-, 2.33-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively.Standard procedures specific to the WY–MT WSC for implementing the Bulletin 17C guidelines include (1) the use of the Expected Moments Algorithm analysis for fitting the log-Pearson Type III distribution, incorporating historical information where applicable; (2) the use of weighted skew coefficients (based on weighting at-site station skew coefficients with generalized skew coefficients from the Bulletin 17B national skew map); and (3) the use of the Multiple Grubbs-Beck Test for identifying potentially influential low flows. For some streamgages, the peak-flow records are not well represented by the standard procedures and require user-specified adjustments informed by hydrologic judgement. The specific characteristics of peak-flow records addressed by the informed-user adjustments include (1) regulated peak-flow records, (2) atypical upper-tail peak-flow records, and (3) atypical lower-tail peak-flow records. In all cases, the informed-user adjustments use the Expected Moments Algorithm fit of the log-Pearson Type III distribution using the at-site station skew coefficient, a manual potentially influential low flow threshold, or both.Appropriate methods can be applied to at-site frequency estimates to provide improved representation of long-term hydroclimatic conditions. The methods for improving at-site frequency estimates by weighting with regional

  2. Influence of modulation frequency in rubidium cell frequency standards

    Science.gov (United States)

    Audoin, C.; Viennet, J.; Cyr, N.; Vanier, J.

    1983-01-01

    The error signal which is used to control the frequency of the quartz crystal oscillator of a passive rubidium cell frequency standard is considered. The value of the slope of this signal, for an interrogation frequency close to the atomic transition frequency is calculated and measured for various phase (or frequency) modulation waveforms, and for several values of the modulation frequency. A theoretical analysis is made using a model which applies to a system in which the optical pumping rate, the relaxation rates and the RF field are homogeneous. Results are given for sine-wave phase modulation, square-wave frequency modulation and square-wave phase modulation. The influence of the modulation frequency on the slope of the error signal is specified. It is shown that the modulation frequency can be chosen as large as twice the non-saturated full-width at half-maximum without a drastic loss of the sensitivity to an offset of the interrogation frequency from center line, provided that the power saturation factor and the amplitude of modulation are properly adjusted.

  3. Relaxation of stresses during reduction of anode supported SOFCs

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Chatzichristodoulou, Christodoulos; Jørgensen, Peter Stanley

    2016-01-01

    To assess the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. This work reports further details on a newly discovered creep phenomenon......, accelerated creep, taking place during the reduction of a Ni-YSZ anode. This relaxes stresses at a much higher rate (~×104) than creep during operation. Thus, the phenomenon of accelerated creep during reduction has to be considered both in the production of stacks and in the analysis of the stress field...... of reduction should decrease significantly over minutes. In this work these internal stresses are measured in-situ before and after the reduction by use of X-ray diffraction. This is done by determining the elastic micro-strains (correlating to the stresses), which are assessed from the widening of the Bragg...

  4. Breakfast frequency among adolescents

    DEFF Research Database (Denmark)

    Pedersen, Trine Pagh; Holstein, Bjørn E; Damsgaard, Mogens Trab

    2016-01-01

    OBJECTIVE: To investigate (i) associations between adolescents' frequency of breakfast and family functioning (close relations to parents, quality of family communication and family support) and (ii) if any observed associations between breakfast frequency and family functioning vary...... (n 3054) from a random sample of forty-one schools. RESULTS: Nearly one-quarter of the adolescents had low breakfast frequency. Low breakfast frequency was associated with low family functioning measured by three dimensions. The OR (95 % CI) of low breakfast frequency was 1·81 (1·40, 2......·33) for adolescents who reported no close relations to parents, 2·28 (1·61, 3·22) for adolescents who reported low level of quality of family communication and 2·09 (1·39, 3·15) for adolescents who reported low level of family support. Joint effect analyses suggested that the odds of low breakfast frequency among...

  5. Nuclear magnetic relaxation by the dipolar EMOR mechanism: General theory with applications to two-spin systems.

    Science.gov (United States)

    Chang, Zhiwei; Halle, Bertil

    2016-02-28

    In aqueous systems with immobilized macromolecules, including biological tissue, the longitudinal spin relaxation of water protons is primarily induced by exchange-mediated orientational randomization (EMOR) of intra- and intermolecular magnetic dipole-dipole couplings. We have embarked on a systematic program to develop, from the stochastic Liouville equation, a general and rigorous theory that can describe relaxation by the dipolar EMOR mechanism over the full range of exchange rates, dipole coupling strengths, and Larmor frequencies. Here, we present a general theoretical framework applicable to spin systems of arbitrary size with symmetric or asymmetric exchange. So far, the dipolar EMOR theory is only available for a two-spin system with symmetric exchange. Asymmetric exchange, when the spin system is fragmented by the exchange, introduces new and unexpected phenomena. Notably, the anisotropic dipole couplings of non-exchanging spins break the axial symmetry in spin Liouville space, thereby opening up new relaxation channels in the locally anisotropic sites, including longitudinal-transverse cross relaxation. Such cross-mode relaxation operates only at low fields; at higher fields it becomes nonsecular, leading to an unusual inverted relaxation dispersion that splits the extreme-narrowing regime into two sub-regimes. The general dipolar EMOR theory is illustrated here by a detailed analysis of the asymmetric two-spin case, for which we present relaxation dispersion profiles over a wide range of conditions as well as analytical results for integral relaxation rates and time-dependent spin modes in the zero-field and motional-narrowing regimes. The general theoretical framework presented here will enable a quantitative analysis of frequency-dependent water-proton longitudinal relaxation in model systems with immobilized macromolecules and, ultimately, will provide a rigorous link between relaxation-based magnetic resonance image contrast and molecular parameters.

  6. Real-time relaxation and kinetics in hot scalar QED: Landau damping

    International Nuclear Information System (INIS)

    Boyanovsky, D.; Vega, H.J. de; Holman, R.; Kumar, S.P.; Pisarski, R.D.

    1998-01-01

    The real time evolution of non-equilibrium expectation values with soft length scales ∼k -1 >(eT) -1 is solved in hot scalar electrodynamics, with a view towards understanding relaxational phenomena in the QGP and the electroweak plasma. We find that the gauge invariant non-equilibrium expectation values relax via power laws to asymptotic amplitudes that are determined by the quasiparticle poles. The long time relaxational dynamics and relevant time scales are determined by the behavior of the retarded self-energy not at the small frequencies, but at the Landau damping thresholds. This explains the presence of power laws and not of exponential decay. In the process we rederive the HTL effective action using non-equilibrium field theory. Furthermore we obtain the influence functional, the Langevin equation and the fluctuation-dissipation theorem for the soft modes, identifying the correlators that emerge in the classical limit. We show that a Markovian approximation fails to describe the dynamics both at short and long times. We find that the distribution function for soft quasiparticles relaxes with a power law through Landau damping. We also introduce a novel kinetic approach that goes beyond the standard Boltzmann equation by incorporating off-shell processes and find that the distribution function for soft quasiparticles relaxes with a power law through Landau damping. We find an unusual dressing dynamics of bare particles and anomalous (logarithmic) relaxation of hard quasiparticles. copyright 1998 The American Physical Society

  7. Relaxation model for extended magnetohydrodynamics: Comparison to magnetohydrodynamics for dense Z-pinches

    International Nuclear Information System (INIS)

    Seyler, C. E.; Martin, M. R.

    2011-01-01

    It is shown that the two-fluid model under a generalized Ohm's law formulation and the resistive magnetohydrodynamics (MHD) can both be described as relaxation systems. In the relaxation model, the under-resolved stiff source terms constrain the dynamics of a set of hyperbolic equations to give the correct asymptotic solution. When applied to the collisional two-fluid model, the relaxation of fast time scales associated with displacement current and finite electron mass allows for a natural transition from a system where Ohm's law determines the current density to a system where Ohm's law determines the electric field. This result is used to derive novel algorithms, which allow for multiscale simulation of low and high frequency extended-MHD physics. This relaxation formulation offers an efficient way to implicitly advance the Hall term and naturally simulate a plasma-vacuum interface without invoking phenomenological models. The relaxation model is implemented as an extended-MHD code, which is used to analyze pulsed power loads such as wire arrays and ablating foils. Two-dimensional simulations of pulsed power loads are compared for extended-MHD and MHD. For these simulations, it is also shown that the relaxation model properly recovers the resistive-MHD limit.

  8. Dielectric relaxation of 2-ethyl-1-hexanol around the glass transition by thermally stimulated depolarization currents.

    Science.gov (United States)

    Arrese-Igor, S; Alegría, A; Colmenero, J

    2015-06-07

    We explore new routes for characterizing the Debye-like and α relaxation in 2-ethyl-1-hexanol (2E1H) monoalcohol by using low frequency dielectric techniques including thermally stimulated depolarization current (TSDC) techniques and isothermal depolarization current methods. In this way, we have improved the resolution of the overlapped processes making it possible the analysis of the data in terms of a mode composition as expected for a chain-like response. Furthermore the explored ultralow frequencies enabled to study dynamics at relatively low temperatures close to the glass transition (Tg). Results show, on the one hand, that Debye-like and α relaxation timescales dramatically approach to each other upon decreasing temperature to Tg. On the other hand, the analysis of partial polarization TSDC data confirms the single exponential character of the Debye-like relaxation in 2E1H and rules out the presence of Rouse type modes in the scenario of a chain-like response. Finally, on crossing the glass transition, the Debye-like relaxation shows non-equilibrium effects which are further emphasized by aging treatment and would presumably emerge as a result of the arrest of the structural relaxation below Tg.

  9. Dielectric relaxation studies of some primary alcohols and their mixture with water

    International Nuclear Information System (INIS)

    Ahmad, S.S.; Yaqub, M.

    2003-01-01

    The complex dielectric constant of ethyl alcohol, methyl alcohol and 1- propanol and their mixtures with water of different concentration, (0 to 100% by weight) at the temperature of 303K has been evaluated, within the frequency range of (100KHz- 100 MHz). Moreover, the viscosity mu of each alcohol and its mixture with water have been measured at this temperature. The dielectric properties have been evaluated by Hartshorn and Ward apparatus. The purpose of this work is to study the influence of aliphatic group, size and shape on the extent of hydrogen bonding and also to obtain the thermodynamic data on hydrogen bond formation in the pure liquid state and its mixture. The width of the semicircle plot determines the distribution of average relaxation time. Dielectric relaxation time in pure alcohols and their water mixture has been calculated from the respected Cole-Cole plot and dielectric data. A single relaxation time of 117.16ps has been obtained for the molecules of pure methanol, whereas, the dielectric data of prophyl alcohol which indicates the viscosity water have been measured at the temperature 303 K. The dielectric properties in distribution of relaxation time, which is in good agreement with the Davidson-cole representation. The molecules in liquid mixture within frequency range, the mixture has more than one relaxation item, leading to the shortening of main relaxation time as compared with the pure alcohol and broadening of the complex permitivity spectra. The dependence of the dielectric relaxation on composition shows a remarkable behavior. Results are discussed in the light of H-bonded molecules. (author)

  10. Zinc chloride modified electronic transport and relaxation studies in barium-tellurite glasses

    Science.gov (United States)

    Dhankhar, Sunil; Kundu, R. S.; Rani, Sunita; Sharma, Preeti; Murugavel, S.; Punia, Rajesh; Kishore, N.

    2017-09-01

    The ac conductivity of halide based tellurium glasses having composition 70 TeO2-(30-x) BaO-x ZnCl2; x = 5, 10, 15, 20 and 25 has been investigated in the frequency range 10-1 Hz to 105Hz and in the temperature range 453 K to 553 K. The frequency and temperature dependent ac conductivity show mixed behaviour with increase in halide content and found to obey Jonscher's universal power law. The values of dc conductivity, crossover frequency and frequency exponent have been estimated from the fitting of experimental data of ac conductivity with Jonscher's universal power law. For determining the conduction mechanism in studied glass system, frequency exponent has been analyzed by various theoretical models. In presently studied glasses, the ac conduction takes place via overlapping large polaron tunneling (OLPT). The values of activation energy for dc conduction (W) and the one associated with relaxation process ( E R) are found to increase with increase in x up to glass sample with x = 15 and thereafter it decrease with increase in zinc chloride content. DC conduction takes place via variable range hopping (VRH) as proposed by Mott with some modification suggested by Punia et al. The value of real part of modulus ( M') is observed to decrease with increase in temperature. The value of stretched exponent (β) obtained from fitting of M'' reveals the presence of non-Debye type of relaxation in presently studied glass samples. Scaling spectra of ac conductivity and values of electric modulus ( M' and M'') collapse into a single master curve for all the compositions and temperatures. The values of relaxation energy ( E R) for all the studied glass compositions are almost equal to W, suggesting that polarons have to overcome same barrier while relaxing and conducting. The conduction and relaxation processes in the studied glass samples are composition and temperature independent. [Figure not available: see fulltext.

  11. Logarithmic superposition of force response with rapid length changes in relaxed porcine airway smooth muscle.

    Science.gov (United States)

    Ijpma, G; Al-Jumaily, A M; Cairns, S P; Sieck, G C

    2010-12-01

    We present a systematic quantitative analysis of power-law force relaxation and investigate logarithmic superposition of force response in relaxed porcine airway smooth muscle (ASM) strips in vitro. The term logarithmic superposition describes linear superposition on a logarithmic scale, which is equivalent to multiplication on a linear scale. Additionally, we examine whether the dynamic response of contracted and relaxed muscles is dominated by cross-bridge cycling or passive dynamics. The study shows the following main findings. For relaxed ASM, the force response to length steps of varying amplitude (0.25-4% of reference length, both lengthening and shortening) are well-fitted with power-law functions over several decades of time (10⁻² to 10³ s), and the force response after consecutive length changes is more accurately fitted assuming logarithmic superposition rather than linear superposition. Furthermore, for sinusoidal length oscillations in contracted and relaxed muscles, increasing the oscillation amplitude induces greater hysteresivity and asymmetry of force-length relationships, whereas increasing the frequency dampens hysteresivity but increases asymmetry. We conclude that logarithmic superposition is an important feature of relaxed ASM, which may facilitate a more accurate prediction of force responses in the continuous dynamic environment of the respiratory system. In addition, the single power-function response to length changes shows that the dynamics of cross-bridge cycling can be ignored in relaxed muscle. The similarity in response between relaxed and contracted states implies that the investigated passive dynamics play an important role in both states and should be taken into account.

  12. Vibrational relaxation dynamics of SD molecules in As2S3: Observation of an anomalous isotope effect

    International Nuclear Information System (INIS)

    Engholm, J.R.; Happek, U.; Rella, C.W.

    1995-01-01

    It is generally assumed that the vibrational relaxation of molecular impurities in crystals and glasses mainly depends on the order of the decay process, with lower order processes leading to more rapid relaxation (a behavior that is known under the term open-quotes gap-lawclose quotes). Here we present measurements that contradict this assumption. Using high intensity psec pulses of the Stanford FEL we measured the relaxation rate of the SD vibrational stretch mode (at a frequency of 1800 cm) by applying a pump-probe technique. We find relaxation rates on the order of 2x10 9 sec -1 , which are a factor of 2 lower than those found for the isotope molecule SH (at a frequency of about 2500 cm - 1 ) in the same host 1 . We recall that the relaxation of the SD vibrational stretch mode is controlled by a lower order process as compared to the SH molecule, which is due to the smaller number of host vibrational quanta to match the energy of the stretch mode; a fact we have confirmed experimentally by temperature dependent relaxation measurements. Thus our remits are in marked contrast to the so-called open-quotes Gap-Lawclose quotes and emphasize the importance of the molecule - host coupling in the relaxation dynamics

  13. Formation probabilities and relaxation rates of muon states in germanium

    International Nuclear Information System (INIS)

    Clawson, C.W.; Haller, E.E.; Crowe, K.M.; Rosenblum, S.S.; Brewer, J.H.; British Columbia Univ., Vancouver

    1981-01-01

    We report the first results of a study of the muonium states in ultra-pure germanium crystals grown under a variety of conditions at Lawrence Berkeley Laboratory. Among the variations studied are: 1) Hydrogen, deuterium, or nitrogen atmosphere during growth; 2) Dislocation-free vs. dislocated crystals; 3) Grown from quartz, graphite, and pyrolytic graphite coated quartz crucibles; 4) n-type vs. p-type. We report a significant difference in the muonium relaxation rate between the dislocated and non-dislocated crystals. (orig.)

  14. Use of relaxation skills in differentially skilled athletes.

    OpenAIRE

    Kudlackova, K.; Eccles, D. W.; Dieffenbach, K.

    2013-01-01

    Objectives: To examine the use of relaxation skills by differentially skilled athletes in relation to the deliberate practice framework. Design: Differentially skilled athletes completed a survey about their use of relaxation skills. Method: 150 athletes representing three skill levels (recreational, college, and professional) completed the deliberate relaxation for sport survey, which assessed relaxation on three deliberate practice dimensions (relevancy, concentration, and ...

  15. Policy Options for Radio Frequency Identification (RFID) Application in Healthcare; a Prospective View: Final Report (D5).

    Science.gov (United States)

    van Oranje-Nassau, Constantijn; Schindler, Helen Rebecca; Vilamovska, Anna-Marie; Botterman, Maarten

    2012-01-01

    This article reviews the state of play of European markets and applications of Radio Frequency Identification (RFID) technology in healthcare in Europe. Based on the current situation the study presents three scenarios for 2020, to describe futures in which the technology and health care sectors develop in different ways. The scenarios were discussed in expert workshops to derive issues that need to be addressed by future policies of the European Union and other stakeholders. The market assessment is based on a review of literature and an analysis of proprietary market data. The information on the state of RFID applications in Health in Europe summarises the results of a literature review, an online Delphi survey, expert interviews and seven cases studies in Europe and the US. The policy analysis is based on the outcomes of a scenario gaming workshop with experts from academia, industry, healthcare providers, policymakers and representatives of patient organisations.

  16. Effective treatment of narcolepsy-like symptoms with high-frequency repetitive transcranial magnetic stimulation: A case report.

    Science.gov (United States)

    Lai, Jian-Bo; Han, Mao-Mao; Xu, Yi; Hu, Shao-Hua

    2017-11-01

    Narcolepsy is a rare sleep disorder with disrupted sleep-architecture. Clinical management of narcolepsy lies dominantly on symptom-driven pharmacotherapy. The treatment role of repetitive transcranial magnetic stimulation (rTMS) for narcolepsy remains unexplored. In this paper, we present a case of a 14-year-old young girl with excessive daytime sleepiness (EDS), cataplexy and hypnagogic hallucinations. After excluding other possible medical conditions, this patient was primarily diagnosed with narcolepsy. The patient received 25 sessions of high-frequency rTMS over the left dorsolateral prefrontal cortex (DLPFC). The symptoms of EDS and cataplexy significantly improved after rTMS treatment. Meanwhile, her score in the Epworth sleep scale (ESS) also remarkably decreased. This case indicates that rTMS may be selected as a safe and effective alternative strategy for treating narcolepsy-like symptoms. Well-designed researches are warranted in future investigations on this topic.

  17. Reported off-leash frequency and perception of risk for gastrointestinal parasitism are not associated in owners of urban park-attending dogs: A multifactorial investigation.

    Science.gov (United States)

    Smith, Anya F; Semeniuk, Christina A D; Rock, Melanie J; Massolo, Alessandro

    2015-07-01

    Associations between park use and infections with gastrointestinal (GI) parasites in dogs (Canis familiaris) have been previously observed, suggesting park use may pose risks for infection in dogs, and potentially, in humans. This study was conducted to establish the overall level of perceived risk of parasitism in dogs, the frequency of unleashing dogs in parks, and to determine if dog owners' risk perceptions of parasite transmission among humans and dogs are associated with the reported frequency of unleashing dogs. From June to September 2010, 635 surveys were administered to dog owners in nine city parks in Calgary, Alberta, by the lead author to explore dog-walking behaviors in parks under differing leashing regulations. From these, a subset of 316 questionnaires were analyzed to examine associations between behavioral and dog demographic factors, risk perception and acceptability of perceived risks of dog and human parasitism, and education regarding parasitism in dogs and humans. Multivariate statistics were conducted using three separate Chi-Square Automatic Interaction Detection (CHAID) decision trees to model risk perception of dogs becoming parasitized while in the park, risk perception of zoonotic transmission, and off-leash frequency. Predictors included recreational behaviors, dog demographics, risk perception of park-based and zoonotic transmission, education regarding parasites, and leashing regulations (e.g. on-leash, off-leash, or mixed management parks). The perceived risk of park-based transmission was relatively higher than perception of zoonotic transmission and the majority of people unleashed their dogs at least some of the time. Risk perception was not associated with off-leash frequency in dogs and risk perception and off-leash frequency were associated with factors other than each other. The results suggest owners may underestimate the potential risks for parasitism related to some dog-walking behaviours, and are relevant for public and

  18. Sedative and muscle relaxant activities of diterpenoids from Phlomidoschema parviflorum

    Directory of Open Access Journals (Sweden)

    Abdur Rauf

    Full Text Available Abstract Phlomidoschema parviflorum (Benth. Vved. (Basionym: Stachys parviflora Benth. Lamiaceae, have significance medicinal importance as it is used in number of health disorders including diarrhea, fever, sore mouth and throat, internal bleeding, weaknesses of the liver and heart genital tumors, sclerosis of the spleen, inflammatory tumors and cancerous ulcers. The present contribution deals with the sedative and muscle relaxant like effects of diterpenoids trivially named stachysrosane and stachysrosane, isolated from the ethyl acetate soluble fraction of P. parviflorum. Both compounds (at 5, 10 and 15 mg/kg, i.p were assessed for their in vivo sedative and muscle relaxant activity in open field and inclined plane test, respectively. The geometries of both compounds were optimized with density functional theory. The molecular docking of both compounds were performed with receptor gamma aminobutyric acid. Both compounds showed marked activity in a dose dependent manner. The docking studies showed that both compounds interact strongly with important residues in receptor gamma aminobutyric acid. The reported data demonstrate that both compounds exhibited significant sedative and muscle relaxant-like effects in animal models, which opens a door for novel therapeutic applications.

  19. Multiplied effect of heat and radiation in chemical stress relaxation

    International Nuclear Information System (INIS)

    Ito, Masayuki

    1981-01-01

    About the deterioration of rubber due to radiation, useful knowledge can be obtained by the measurement of chemical stress relaxation. As an example, the rubber coating of cables in a reactor containment vessel is estimated to be irradiated by weak radiation at the temperature between 60 and 90 deg C for about 40 years. In such case, it is desirable to establish the method of accelerated test of the deterioration. The author showed previously that the law of time-dose rate conversion holds in the case of radiation. In this study, the chemical stress relaxation to rubber was measured by the simultaneous application of heat and radiation, and it was found that there was the multiplied effect of heat and radiation in the stress relaxation speed. Therefore the factor of multiplication of heat and radiation was proposed to describe quantitatively the degree of the multiplied effect. The chloroprene rubber used was offered by Hitachi Cable Co., Ltd. The experimental method and the results are reported. The multiplication of heat and radiation is not caused by the direct cut of molecular chains by radiation, instead, it is based on the temperature dependence of various reaction rates at which the activated species reached the cut of molecular chains through complex reaction mechanism and the temperature dependence of the diffusion rate of oxygen in rubber. (Kako, I.)

  20. A photonic ultra-wideband pulse generator based on relaxation oscillations of a semiconductor laser

    DEFF Research Database (Denmark)

    Yu, Xianbin; Gibbon, Timothy Braidwood; Pawlik, Michal

    2009-01-01

    A photonic ultra-wideband (UWB) pulse generator based on relaxation oscillations of a semiconductor laser is proposed and experimentally demonstrated. We numerically simulate the modulation response of a direct modulation laser (DML) and show that due to the relaxation oscillations of the laser......, the generated signals with complex shape in time domain match the Federal Communications Commission (FCC) mask in the frequency domain. Experimental results using a DML agree well with simulation predictions. Furthermore, we also experimentally demonstrate the generation of FCC compliant UWB signals...

  1. Effect of alkali ion on relaxation properties of binary alkali-borate glasses

    International Nuclear Information System (INIS)

    Lomovskoj, V.A.; Bartenev, G.M.

    1992-01-01

    Method of relaxation spectrometry were used to analyze the data on internal friction spectra of lithium, sodium, potassium and rubidium alkali-borate glasses in wide range of temperatures and frequencies. The nature of two relaxation processes was clarified: β m -process, related with mobility of alkaline metal cations, and α-process (vitrification), conditioned by system transformation from viscous-flow to vitreous state. It is shown that atomic-molecular mechanism of vitrification process changes when passing from vitreous B 2 O 3 to alkali-borate glasses

  2. Dielectric relaxation and hydrogen bonding interaction in xylitol-water mixtures using time domain reflectometry

    Science.gov (United States)

    Rander, D. N.; Joshi, Y. S.; Kanse, K. S.; Kumbharkhane, A. C.

    2016-01-01

    The measurements of complex dielectric permittivity of xylitol-water mixtures have been carried out in the frequency range of 10 MHz-30 GHz using a time domain reflectometry technique. Measurements have been done at six temperatures from 0 to 25 °C and at different weight fractions of xylitol (0 xylitol-water can be well described by Cole-Davidson model having an asymmetric distribution of relaxation times. The dielectric parameters such as static dielectric constant and relaxation time for the mixtures have been evaluated. The molecular interaction between xylitol and water molecules is discussed using the Kirkwood correlation factor ( g eff ) and thermodynamic parameter.

  3. Phonon-impurity relaxation and acoustic wave absorption in yttrium-aluminium garnet crystals with impurities

    International Nuclear Information System (INIS)

    Ivanov, S.N.; Kotelyanskij, I.M.; Medved', V.V.

    1983-01-01

    The experimental results of investigations of the influence of substitution impurities in the yttrium-aluminium garnet lattice on absorption of high-frequency acoustic waves are presented. It is shown that the phonon-impurity relaxation processses affect at most the wave absorption and have resonance character when the acoustic wave interacts with the thermal phonon group in the vicinity of the perturbed part of the phonon spectrum caused by the impurity. The differences of time values between inelastic and elastic thermal phonons relaxations determined from the data on longitudinal and shear waves in pure and impurity garnet crystals are discussed

  4. Frequency of Self-Reported Concussion Amongst Professional and Semi-Professional Footballers in Ireland During the 2014 Season: a Cross-Sectional Study.

    Science.gov (United States)

    Coffey, Nicola; Lawless, Martin; Kelly, Seamus; Buggy, Conor

    2018-01-08

    This paper examines the occupational risk of concussion amongst professional and semi-professional footballers in Ireland during the 2014 League of Ireland season. As part of a broader nationally representative study examining occupational safety and health (OSH) awareness amongst professional footballers, this empirical quantitative study, utilising a convenience sample is the first and largest investigation of the frequency of, and attitudes towards, concussion and concussion reporting amongst Irish senior professional and semi-professional footballers. A census survey using an anonymous questionnaire was provided to available League of Ireland clubs between March and May 2015. Permission to access players was provided by the Professional Footballers Association of Ireland. This convenience sample was determined by club availability in relation to match fixtures. Participation by the footballers was voluntary. At the time, there were 250 professional and semi-professional players within the League available to participate. A total of 149 footballers participated in the study. Sixty percent of the participants were employed on a semi-professional basis and the majority of all participants were aged between 18 and 30. 15.7% of the participants reported having received a concussion in the 2014 season with semi-professional players having a noticeably higher (though not significant) reporting rate. Analysis indicated that there was a significant association between playing position and concussion reporting with defenders having the greater odds of reporting a concussion than other playing positions. Professional and semi-professional footballers have a relatively equal risk of receiving a concussion. This research is the first major investigation of the self-reported frequency of, and attitudes towards, concussion amongst Irish senior professional and semi-professional footballers. The results have important implications for coaches, clinicians, parents, players and

  5. Relaxation processes in rotational motion

    International Nuclear Information System (INIS)

    Broglia, R.A.

    1986-01-01

    At few MeV above the yrast line the normally strong correlations among γ-ray energies in a rotational sequence become weaker. This observation can be interpreted as evidence for the damping of rotational motion in hot nuclei. It seems possible to relate the spreading width of the E2-rotational decay strength to the spread in frequency Δω 0 of rotational bands. The origin of these fluctuations is found in: (1) fluctuations in the occupation of special single-particle orbits which contribute a significant part of the total angular momentum; and (2) fluctuations in the moment of inertia induced by vibrations of the nuclear shape. Estimates of Δω 0 done making use of the hundred-odd known discrete rotational bands in the rare-earth region lead, for moderate spin and excitation energies (I ≅ 30 and U ≅ 3 to 4 MeV), to rotational spreading widths of the order of 60 to 160 keV in overall agreement with the data. 24 refs

  6. Fractional calculus model of articular cartilage based on experimental stress-relaxation

    Science.gov (United States)

    Smyth, P. A.; Green, I.

    2015-05-01

    Articular cartilage is a unique substance that protects joints from damage and wear. Many decades of research have led to detailed biphasic and triphasic models for the intricate structure and behavior of cartilage. However, the models contain many assumptions on boundary conditions, permeability, viscosity, model size, loading, etc., that complicate the description of cartilage. For impact studies or biomimetic applications, cartilage can be studied phenomenologically to reduce modeling complexity. This work reports experimental results on the stress-relaxation of equine articular cartilage in unconfined loading. The response is described by a fractional calculus viscoelastic model, which gives storage and loss moduli as functions of frequency, rendering multiple advantages: (1) the fractional calculus model is robust, meaning that fewer constants are needed to accurately capture a wide spectrum of viscoelastic behavior compared to other viscoelastic models (e.g., Prony series), (2) in the special case where the fractional derivative is 1/2, it is shown that there is a straightforward time-domain representation, (3) the eigenvalue problem is simplified in subsequent dynamic studies, and (4) cartilage stress-relaxation can be described with as few as three constants, giving an advantage for large-scale dynamic studies that account for joint motion or impact. Moreover, the resulting storage and loss moduli can quantify healthy, damaged, or cultured cartilage, as well as artificial joints. The proposed characterization is suited for high-level analysis of multiphase materials, where the separate contribution of each phase is not desired. Potential uses of this analysis include biomimetic dampers and bearings, or artificial joints where the effective stiffness and damping are fundamental parameters.

  7. Temperature-dependent structural relaxation in As{sub 40}Se{sub 60} glass

    Energy Technology Data Exchange (ETDEWEB)

    Golovchak, R., E-mail: roman_ya@yahoo.com [Lviv Sci. and Res. Institute of Materials of SRC ' Carat' , 202 Stryjska str., 79031 Lviv (Ukraine); Kozdras, A. [Opole University of Technology, 75, Ozimska str., Opole, PL-45370 (Poland); Academy of Management and Administration, 18 Niedzialkowski str., Opole, PL-45085 (Poland); Shpotyuk, O. [Jan Dlugosz University, 13/15, al. Armii Krajowej, 42201, Czestochowa (Poland); Gorecki, Cz. [Opole University of Technology, 75, Ozimska str., Opole, PL-45370 (Poland); Kovalskiy, A.; Jain, H. [Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States)

    2011-08-01

    The origin of structural relaxation in As{sub 40}Se{sub 60} glass at different annealing temperatures is studied by differential scanning calorimetry (DSC) and in situ extended X-ray absorption fine structure (EXAFS) methods. Strong physical aging effect, expressed through the increase of endothermic peak area in the vicinity of T{sub g}, is recorded by DSC technique at the annealing temperatures T{sub a}>90{sup o}C. EXAFS data show that the observed structural relaxation is not associated with significant changes in the short-range order of this glass. An explanation is proposed for this relaxation behavior assuming temperature-dependent constraints. -- Highlights: → In this study we report experimental evidence for temperature-dependent constraints theory. → Structural relaxation of As{sub 2}Se{sub 3} glass at higher annealing temperatures is studied by DSC technique. → Accompanied changes in the structure are monitored by in situ EXAFS measurements.

  8. Relaxation rates of gene expression kinetics reveal the feedback signs of autoregulatory gene networks

    Science.gov (United States)

    Jia, Chen; Qian, Hong; Chen, Min; Zhang, Michael Q.

    2018-03-01

    The transient response to a stimulus and subsequent recovery to a steady state are the fundamental characteristics of a living organism. Here we study the relaxation kinetics of autoregulatory gene networks based on the chemical master equation model of single-cell stochastic gene expression with nonlinear feedback regulation. We report a novel relation between the rate of relaxation, characterized by the spectral gap of the Markov model, and the feedback sign of the underlying gene circuit. When a network has no feedback, the relaxation rate is exactly the decaying rate of the protein. We further show that positive feedback always slows down the relaxation kinetics while negative feedback always speeds it up. Numerical simulations demonstrate that this relation provides a possible method to infer the feedback topology of autoregulatory gene networks by using time-series data of gene expression.

  9. Smooth muscle relaxant activity of Crocus sativus (saffron and its constituents: possible mechanisms

    Directory of Open Access Journals (Sweden)

    Amin Mokhtari-Zaer

    2015-08-01

    Full Text Available Saffron, Crocus sativus L. (C. sativus is rich in carotenoids and used in traditional medicine for treatment of various conditions such as coughs, stomach disorders, amenorrhea, asthma and cardiovascular disorders. These therapeutic effects of the plant are suggested to be due to its relaxant effect on smooth muscles. The effect of C. sativus and its constituents on different smooth muscles and the underlying mechanisms have been studied. Several studies have shown the relaxant effects of C. sativus and its constituents including safranal, crocin, crocetin and kaempferol on blood vessels. In addition, it was reported that saffron stigma lowers systolic blood pressure. The present review highlights the relaxant effects of C. sativus and its constituents on various smooth muscles. The possible mechanisms of this relaxing effect including activation of ß2-adrenoceptors, inhibition of histamine H1 and muscarinic receptors and calcium channels and modulation of nitric oxide (NO are also reviewed.

  10. Relaxation approximations to second-order traffic flow models by high-resolution schemes

    International Nuclear Information System (INIS)

    Nikolos, I.K.; Delis, A.I.; Papageorgiou, M.

    2015-01-01

    A relaxation-type approximation of second-order non-equilibrium traffic models, written in conservation or balance law form, is considered. Using the relaxation approximation, the nonlinear equations are transformed to a semi-linear diagonilizable problem with linear characteristic variables and stiff source terms with the attractive feature that neither Riemann solvers nor characteristic decompositions are in need. In particular, it is only necessary to provide the flux and source term functions and an estimate of the characteristic speeds. To discretize the resulting relaxation system, high-resolution reconstructions in space are considered. Emphasis is given on a fifth-order WENO scheme and its performance. The computations reported demonstrate the simplicity and versatility of relaxation schemes as numerical solvers

  11. Frequency of reporting on patient and public involvement (PPI) in research studies published in a general medical journal: a descriptive study.

    Science.gov (United States)

    Price, Amy; Schroter, Sara; Snow, Rosamund; Hicks, Melissa; Harmston, Rebecca; Staniszewska, Sophie; Parker, Sam; Richards, Tessa

    2018-03-23

    While documented plans for patient and public involvement (PPI) in research are required in many grant applications, little is known about how frequently PPI occurs in practice. Low levels of reported PPI may mask actual activity due to limited PPI reporting requirements. This research analysed the frequency and types of reported PPI in the presence and absence of a journal requirement to include this information. A before and after comparison of PPI reported in research papers published in The BMJ before and 1 year after the introduction of a journal policy requiring authors to report if and how they involved patients and the public within their papers. Between 1 June 2013 and 31 May 2014, The BMJ published 189 research papers and 1 (0.5%) reported PPI activity. From 1 June 2015 to 31 May 2016, following the introduction of the policy, The BMJ published 152 research papers of which 16 (11%) reported PPI activity. Patients contributed to grant applications in addition to designing studies through to coauthorship and participation in study dissemination. Patient contributors were often not fully acknowledged; 6 of 17 (35%) papers acknowledged their contributions and 2 (12%) included them as coauthors. Infrequent reporting of PPI activity does not appear to be purely due to a failure of documentation. Reporting of PPI activity increased after the introduction of The BMJ 's policy, but activity both before and after was low and reporting was inconsistent in quality. Journals, funders and research institutions should collaborate to move us from the current situation where PPI is an optional extra to one where PPI is fully embedded in practice throughout the research process. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  12. Low-relaxation spin waves in laser-molecular-beam epitaxy grown nanosized yttrium iron garnet films

    Energy Technology Data Exchange (ETDEWEB)

    Lutsev, L. V., E-mail: l-lutsev@mail.ru; Korovin, A. M.; Bursian, V. E.; Gastev, S. V.; Fedorov, V. V.; Suturin, S. M.; Sokolov, N. S. [Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation)

    2016-05-02

    Synthesis of nanosized yttrium iron garnet (Y{sub 3}Fe{sub 5}O{sub 12}, YIG) films followed by the study of ferromagnetic resonance (FMR) and spin wave propagation in these films is reported. The YIG films were grown on gadolinium gallium garnet substrates by laser molecular beam epitaxy. It has been shown that spin waves propagating in YIG deposited at 700 °C have low damping. At the frequency of 3.29 GHz, the spin-wave damping parameter is less than 3.6 × 10{sup −5}. Magnetic inhomogeneities of the YIG films give the main contribution to the FMR linewidth. The contribution of the relaxation processes to the FMR linewidth is as low as 1.2%.

  13. Asymptotic representation of relaxation oscillations in lasers

    CERN Document Server

    Grigorieva, Elena V

    2017-01-01

    In this book we analyze relaxation oscillations in models of lasers with nonlinear elements controlling light dynamics. The models are based on rate equations taking into account periodic modulation of parameters, optoelectronic delayed feedback, mutual coupling between lasers, intermodal interaction and other factors. With the aim to study relaxation oscillations we present the special asymptotic method of integration for ordinary differential equations and differential-difference equations. As a result, they are reduced to discrete maps. Analyzing the maps we describe analytically such nonlinear phenomena in lasers as multistability of large-amplitude relaxation cycles, bifurcations of cycles, controlled switching of regimes, phase synchronization in an ensemble of coupled systems and others. The book can be fruitful for students and technicians in nonlinear laser dynamics and in differential equations.

  14. Relaxation of the magnetization in magnetic molecules

    Science.gov (United States)

    Carretta, S.; Bianchi, A.; Liviotti, E.; Santini, P.; Amoretti, G.

    2006-04-01

    Several mechanisms characterize the relaxation dynamics in magnetic molecules. We investigate two of them, spin-lattice coupling and incoherent quantum tunneling. The effect of the phonon heat bath is studied by analyzing the exponential time decay of the autocorrelation of the magnetization. We show that in ferromagnetic (Cu6) and antiferromagnetic (Fe6) molecular rings this decay is characterized by a single characteristic time. At very low temperature, relaxation through incoherent quantum tunneling may occur in nanomagnets such as Fe8 or Ni4. The mixing between levels with different values of the total spin (S mixing) greatly influences this mechanism. In particular, we demonstrate that a fourth-order anisotropy term O44, required to interpret experimental electron paramagnetic resonance and relaxation data in Ni4, naturally arises when S mixing is considered in calculations.

  15. Excited-state relaxation of some aminoquinolines

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The absorption and fluorescence spectra, fluorescence quantum yields and lifetimes, and fluorescence rate constants ( k f of 2-amino-3-( 2 ′ -benzoxazolylquinoline (I, 2-amino-3-( 2 ′ -benzothiazolylquinoline (II, 2-amino-3-( 2 ′ -methoxybenzothiazolyl-quinoline (III, 2-amino-3-( 2 ′ -benzothiazolylbenzoquinoline (IV at different temperatures have been measured. The shortwavelength shift of fluorescence spectra of compounds studied (23–49 nm in ethanol as the temperature decreases (the solvent viscosity increases points out that the excited-state relaxation process takes place. The rate of this process depends essentially on the solvent viscosity, but not the solvent polarity. The essential increasing of fluorescence rate constant k f (up to about 7 times as the solvent viscosity increases proves the existence of excited-state structural relaxation consisting in the mutual internal rotation of molecular fragments of aminoquinolines studied, followed by the solvent orientational relaxation.

  16. Relaxation oscillation logic in Josephson junction circuits

    International Nuclear Information System (INIS)

    Fulton, T.A.

    1981-01-01

    A dc powered, self-resetting Josephson junction logic circuit relying on relaxation oscillations is described. A pair of Josephson junction gates are connected in series, a first shunt is connected in parallel with one of the gates, and a second shunt is connected in parallel with the series combination of gates. The resistance of the shunts and the dc bias current bias the gates so that they are capable of undergoing relaxation oscillations. The first shunt forms an output line whereas the second shunt forms a control loop. The bias current is applied to the gates so that, in the quiescent state, the gate in parallel with the second shunt is at V O, and the other gate is undergoing relaxation oscillations. By controlling the state of the first gate with the current in the output loop of another identical circuit, the invert function is performed

  17. Muon spin relaxation in ferromagnets. Pt. 1

    International Nuclear Information System (INIS)

    Lovesey, S.W.; Karlsson, E.B.

    1991-04-01

    Expressions for the dipolar and hyperfine contributions to the relaxation rate of muons implanted in a ferromagnet are presented and analysed using the Heisenberg model of spin-waves including dipolar and Zeeman energies. Calculations for EuO indicate that relaxation is likely to be dominated by the hyperfine mechanism, even if the ratio of the hyperfine and dipolar coupling constants is small. The hyperfine mechanism is sensitive to the dipolar energy of the atomic spins, whereas the dipolar mechanisms depend essentially on the exchange energy. For both mechanisms there is an almost quadratic dependence on temperature, throughout much of the ordered magnetic phase, which reflects two-spin-wave difference events from the Raman-type relaxation processes. (author)

  18. Relaxation and Diffusion in Complex Systems

    CERN Document Server

    Ngai, K L

    2011-01-01

    Relaxation and Diffusion in Complex Systems comprehensively presents a variety of experimental evidences of universal relaxation and diffusion properties in complex materials and systems. The materials discussed include liquids, glasses, colloids, polymers, rubbers, plastic crystals and aqueous mixtures, as well as carbohydrates, biomolecules, bioprotectants and pharmaceuticals. Due to the abundance of experimental data, emphasis is placed on glass-formers and the glass transition problem, a still unsolved problem in condensed matter physics and chemistry. The evidence for universal properties of relaxation and diffusion dynamics suggests that a fundamental physical law is at work. The origin of the universal properties is traced to the many-body effects of the interaction, rigorous theory of which does not exist at the present time. However, using solutions of simplified models as guides, key quantities have been identified and predictions of the universal properties generated. These predictions from Ngai’...

  19. Electron relaxation properties of Ar magnetron plasmas

    Science.gov (United States)

    Xinjing, CAI; Xinxin, WANG; Xiaobing, ZOU

    2018-03-01

    An understanding of electron relaxation properties in plasmas is of importance in the application of magnetrons. An improved multi-term approximation of the Boltzmann equation is employed to study electron transport and relaxation properties in plasmas. Elastic, inelastic and nonconservative collisions between electrons and neutral particles are considered. The expressions for the transport coefficients are obtained using the expansion coefficients and the collision operator term. Numerical solutions of the matrix equations for the expansion coefficients are also investigated. Benchmark calculations of the Reid model are presented to demonstrate the accuracy of the improved multi-term approximation. It is shown that the two-term approximation is generally not accurate enough and the magnetic fields can reduce the anisotropy of the velocity distribution function. The electron relaxation properties of Ar plasmas in magnetrons for various magnetic fields are studied. It is demonstrated that the energy parameters change more slowly than the momentum parameters.

  20. A broadband damper design inspired by cartilage-like relaxation mechanisms

    Science.gov (United States)

    Liu, Lejie; Usta, Ahmet D.; Eriten, Melih

    2017-10-01

    In this study, we introduce a broadband damper design inspired by the cartilage-like relaxation mechanisms. In particular, we study broadband (static to 10 kHz) dissipative properties of model cartilage systems by probe-based static and dynamic indentation, and validate that fractional Zener models can simulate the empirical data up to a desirable accuracy within the frequency range of interest. Utilizing these observations, we design a composite damper design where a poroelastic layer is sandwiched between two hard materials, and load transfer occurs across interfaces with multiple length scales. Modeling those interfaces with fractional Zener elements in parallel configuration, and manipulating the distribution of the Zener elements across different peak relaxation frequencies, we obtain a relatively constant loss factor within an unprecedented frequency range (3-3 kHz). We also discuss how these findings can be employed in a practical damping design.

  1. Terahertz-frequency dielectric response of liquids

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd; Møller, Uffe; Cooke, David

    The dielectric response of liquids spans many decades in frequency. The dielectric response of a polar liquid is typically determined by relaxational dynamics of the dipolar moments of the liquid. In contrast, the dielectric response of a nonpolar liquid is determined by much weaker collision......-induced dipole moments. In the polar liquid water the fastest relaxational dynamics is found at terahertz frequencies, just below the first intermolecular vibrational and librational modes. In this presentation we will discuss optical terahertz spectroscopic techniques for measurement of the full dielectric...... function of liquids at terahertz frequencies. We will review the current understanding of the high-frequency dielectric spectrum of water, and discuss the relation between the dielectric spectrum and the thermodynamic properties of certain aqueous solutions....

  2. Multi-Phonon Relaxation of H^- Local Modes in CaF_2

    Science.gov (United States)

    Davison, C. P.; Happek, U.; Campbell, J. A.; Engholm, J. R.; Schwettman, H. A.

    1998-03-01

    Local modes play an important role in the relaxation of vibrational modes of small molecules in solids (J.R. Engholm, C.W. Rella, H.A. Schwettman, and U. Happek; Phys. Rev. Lett. 77), 1302 (1996)., but only few attempts have been reported to study the relaxation of these local modes. Here we report on experiments to investigate the non-radiative relaxation of H^- local modes in CaF_2. Using a pump-probe technique, saturation experiments on the H^- local modes, both interstitial and substitutional, were performed at the Stanford Free Electron Laser Center. At low temperature we find a relaxation time T1 of 45 psec for the substitutional H^- local mode, and a more rapid relaxation for the interstitial H^- local modes next to La^3+ and Lu^3+ impurities. Information on the decay channels of the local modes are obtained from the characteristic temperature dependence of the relaxation rates. This work is supported in part by the ONR, Grant No. N00014-94-1024.

  3. Navigated Percutaneous Lung Ablation under High-Frequency Jet Ventilation of a Metastasis from a Wilms’ Tumour: A Paediatric Case Report

    Directory of Open Access Journals (Sweden)

    Jacob Freedman

    2016-07-01

    Full Text Available This is a case report of microwave energy being used to ablate an inoperable metastasis of a Wilms’ tumour in a 6-year-old boy using state-of-the-art navigated computed tomography targeting and high-frequency jet ventilation to reduce organ displacement and the potential risk of procedure-related pneumothorax. After the ablation, the young boy had high-dose chemotherapy followed by an autologous stem cell transplantation with rapid reduction of three recurrent right-sided lung metastases.

  4. Abrupt relaxation in high-spin molecules

    International Nuclear Information System (INIS)

    Chang, C.-R.; Cheng, T.C.

    2000-01-01

    Mean-field model suggests that the rate of resonant quantum tunneling in high-spin molecules is not only field-dependent but also time-dependent. The relaxation-assisted resonant tunneling in high-spin molecules produces an abrupt magnetization change during relaxation. When the applied field is very close to the resonant field, a time-dependent interaction field gradually shifts the energies of different collective spin states, and magnetization tunneling is observed as two energies of the spin states coincide

  5. Relaxed plasmas in external magnetic fields

    International Nuclear Information System (INIS)

    Spies, G.O.; Li, J.

    1991-08-01

    The well-known theory of relaxed plasmas (Taylor states) is extended to external magnetic fields whose field lines intersect the conducting toroidal boundary. Application to an axially symmetric, large-aspect-ratio torus with circular cross section shows that the maximum pinch ratio, and hence the phenomenon of current saturation, is independent of the external field. The relaxed state is explicitly given for an external octupole field. In this case, field reversal is inhibited near parts of the boundary if the octupole generates magnetic x-points within the plasma. (orig.)

  6. Spin transport and relaxation in graphene

    International Nuclear Information System (INIS)

    Han Wei; McCreary, K.M.; Pi, K.; Wang, W.H.; Li Yan; Wen, H.; Chen, J.R.; Kawakami, R.K.

    2012-01-01

    We review our recent work on spin injection, transport and relaxation in graphene. The spin injection and transport in single layer graphene (SLG) were investigated using nonlocal magnetoresistance (MR) measurements. Spin injection was performed using either transparent contacts (Co/SLG) or tunneling contacts (Co/MgO/SLG). With tunneling contacts, the nonlocal MR was increased by a factor of ∼1000 and the spin injection/detection efficiency was greatly enhanced from ∼1% (transparent contacts) to ∼30%. Spin relaxation was investigated on graphene spin valves using nonlocal Hanle measurements. For transparent contacts, the spin lifetime was in the range of 50-100 ps. The effects of surface chemical doping showed that for spin lifetimes in the order of 100 ps, charged impurity scattering (Au) was not the dominant mechanism for spin relaxation. While using tunneling contacts to suppress the contact-induced spin relaxation, we observed the spin lifetimes as long as 771 ps at room temperature, 1.2 ns at 4 K in SLG, and 6.2 ns at 20 K in bilayer graphene (BLG). Furthermore, contrasting spin relaxation behaviors were observed in SLG and BLG. We found that Elliot-Yafet spin relaxation dominated in SLG at low temperatures whereas Dyakonov-Perel spin relaxation dominated in BLG at low temperatures. Gate tunable spin transport was studied using the SLG property of gate tunable conductivity and incorporating different types of contacts (transparent and tunneling contacts). Consistent with theoretical predictions, the nonlocal MR was proportional to the SLG conductivity for transparent contacts and varied inversely with the SLG conductivity for tunneling contacts. Finally, bipolar spin transport in SLG was studied and an electron-hole asymmetry was observed for SLG spin valves with transparent contacts, in which nonlocal MR was roughly independent of DC bias current for electrons, but varied significantly with DC bias current for holes. These results are very important for

  7. Nonlocal and collective relaxation in stellar systems

    Science.gov (United States)

    Weinberg, Martin D.

    1993-01-01

    The modal response of stellar systems to fluctuations at large scales is presently investigated by means of analytic theory and n-body simulation; the stochastic excitation of these modes is shown to increase the relaxation rate even for a system which is moderately far from instability. The n-body simulations, when designed to suppress relaxation at small scales, clearly show the effects of large-scale fluctuations. It is predicted that large-scale fluctuations will be largest for such marginally bound systems as forming star clusters and associations.

  8. NMR relaxation times of natural rubber latex

    International Nuclear Information System (INIS)

    Harun, S.; Aziz, H.; Basir, Z.

    1994-01-01

    NMR relaxation times T sub 1 and T sub 2 of natural rubber latex have been measured at 25 degree C on a pulsed NMR spectrometer. The work focuses on the variation of the relaxation times with the amount of water content from 0% to 50%. The water content was adjusted by centrifuging and removing a certain amount of water from the sample. The data were analysed using a biexponential fitting procedure which yields simultaneously either T sub 1a and T sub 1b or T sub 2a and T sub 2b. The amount of solid was compared with the known amount of dry rubber content

  9. Green--Kubo formula for collisional relaxation

    International Nuclear Information System (INIS)

    Visscher, P.B.

    1988-01-01

    In this paper we generalize the Green--Kubo method (usually used for obtaining formulas for transport coefficients involving conserved densities) to relaxation processes occurring during collisions, such as the transfer of energy from vibrational to translational modes in a molecular fluid. We show that the relaxation rate can be calculated without evaluating time correlation functions over long times, and can in fact be written as a sum over collisions which makes the relation between the Green--Kubo method and approximate independent-collision models much clearer

  10. Exciton-relaxation dynamics in lead halides

    International Nuclear Information System (INIS)

    Iwanaga, Masanobu; Hayashi, Tetsusuke

    2003-01-01

    We survey recent comprehensive studies of exciton relaxation in the crystals of lead halides. The luminescence and electron-spin-resonance studies have revealed that excitons in lead bromide spontaneously dissociate and both electrons and holes get self-trapped individually. Similar relaxation has been also clarified in lead chloride. The electron-hole separation is ascribed to repulsive correlation via acoustic phonons. Besides, on the basis of the temperature profiles of self-trapped states, we discuss the origin of luminescence components which are mainly induced under one-photon excitation into the exciton band in lead fluoride, lead chloride, and lead bromide

  11. Point defect relaxation volumes for copper

    International Nuclear Information System (INIS)

    Miller, K.M.

    1979-11-01

    The methods used for the determination of point defect relaxation volumes are discussed and it is shown that a previous interatomic potential derived for copper is inaccurate and results obtained using it are invalid. A new interatomic potential has been produced for copper and a computer simulation of point and planar defects carried out. A vacancy relaxation volume of -0.33 atomic volumes has been found with interstitial values in the range 1.7 to 2.0 atomic volumes. It is shown that these values in current theories of irradiation induced swelling lead to an anomalously high value for dislocation bias compared with that determined experimentally. (author)

  12. Low frequency noise study.

    Science.gov (United States)

    2007-04-01

    This report documents a study to investigate human response to the low-frequency : content of aviation noise, or low-frequency noise (LFN). The study comprised field : measurements and laboratory studies. The major findings were: : 1. Start-of-takeof...

  13. Frequency control modelling - basics

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Sørensen, Poul Ejnar; Zeni, Lorenzo

    2016-01-01

    The purpose of this report is to provide an introduction on how the system balance in an island system can be maintained by controlling the frequency. The power balance differential equation, which is fundamental in understanding the effect on the system frequency of the unbalance between...

  14. Magnetic relaxation phenomena in the chiral magnet Fe1 -xCoxSi : An ac susceptibility study

    Science.gov (United States)

    Bannenberg, L. J.; Lefering, A. J. E.; Kakurai, K.; Onose, Y.; Endoh, Y.; Tokura, Y.; Pappas, C.

    2016-10-01

    We present a systematic study of the ac susceptibility of the chiral magnet Fe1 -xCoxSi with x =0.30 covering four orders of magnitude in frequencies from 0.1 Hz to 1 kHz, with particular emphasis to the pronounced history dependence. Characteristic relaxation times ranging from a few milliseconds to tens of seconds are observed around the skyrmion lattice A phase, the helical-to-conical transition and in a region above TC. The distribution of relaxation frequencies around the A phase is broad, asymmetric, and originates from multiple coexisting relaxation processes. The pronounced dependence of the magnetic phase diagram on the magnetic history and cooling rates as well as the asymmetric frequency dependence and slow dynamics suggest more complicated physical phenomena in Fe0.7Co0.3Si than in other chiral magnets.

  15. High frequency of parasitic and viral stool pathogens in patients with active ulcerative colitis: report from a tropical country.

    Science.gov (United States)

    Banerjee, Debabrata; Deb, Rachana; Dar, Lalit; Mirdha, Bijay R; Pati, Sunil K; Thareja, Sandeep; Falodia, Sushil; Ahuja, Vineet

    2009-01-01

    Diarrhoeal relapses in patients with ulcerative colitis (UC) may be associated with enteric infections and its diagnosis may lessen avoidable exposure to corticosteroids and/or immunosuppressants. The purpose of this study was to assess the frequency of stool pathogens (parasitic and viral) in patients with active UC. This prospective cross-sectional study included 49 consecutive patients (32 M, 17 F, mean age 35.8+/-12 years) with active UC. Three stool samples were collected from each patient and examined for parasitic infection. Rectal biopsies were obtained during sigmoidoscopy to demonstrate cytomegalovirus (CMV) inclusion bodies and to conduct qualitative polymerase chain reaction (PCR) for CMV and herpes simplex virus (HSV) DNA detection. Median duration of illness was 3.9+/-3.7 years and 83.7% of the patients had moderate to severe disease. The prevalence of parasitic infections in UC was 12%. The organisms isolated were Strongyloides stercoralis in 4%, Ankylostoma duodenale in 4%, Cryptosporidium in 2% and Entamoeba histolytica in 2% of the patients. The prevalence of CMV and HSV in rectal biopsies using qualitative PCR was 8% and 10%, respectively. No predictive factor was identified with CMV superinfection in patients with active UC. In India there is a high prevalence of parasitic and viral infections in patients with active UC. The results of the study suggest that, in tropical countries with a known high prevalence of parasitic diseases, aggressive evaluation for parasitic and viral infections should be carried out, as early identification and prompt treatment of such infections can improve the clinical course of patients with active UC.

  16. Preliminary survey on the distribution of medical equipment and frequency of diagnostic and therapeutic procedures in Brazil: a contribution to the UNSCEAR report

    International Nuclear Information System (INIS)

    Biazotto, Bruna; Taboza de Oliveira, Alexandre; Baptista de Freitas, Marcelo

    2008-01-01

    Information about Brazil published in the UNSCEAR 2000 report are still scarce when compared to others countries. In this study, a survey on the distribution of medical equipment (X-ray generators, ultrasound, CT and MRI scanners, nuclear medicine equipment and teletherapy and brachytherapy units) and frequency of diagnostic and therapeutic procedures at the various Brazilian States was carried out. The overall information was obtained from a national database supported by the Brazilian Ministry of Health through the Computer Science Department of the National Health System (SUS - Sistema Unico de Saude). The distribution of equipment and the annual frequency of each type of procedure were analyzed considering the five geographical regions that form the country and their respective population. Temporal and regional trends in the annual frequency of procedures for 2000-2007 were also summarized in this study. National annual frequencies for the total of all medical X-ray examinations (259.0 examinations per 1000 population) were evaluated. Some examples can be given from chest, mammography and CT examinations: 67.4, 30.2 and 7.2 per 1000 population, respectively. In addition, annual frequencies for other modalities of diagnostic imaging have also been estimated: 61.5, 1.6 and 1.4 per 1000 population for ultrasound, nuclear medicine and MRI procedures, respectively. A total of 38.7 therapeutic procedures per 1000 population (teletherapy and brachytherapy) are annually performed in the country. The health services localized in Brazil comprised a total number of 253.1 diagnostic imaging equipment per million population, without considering dental X-ray. Amongst them, X-ray equipment used in common radiological examinations (chest, skull, spine, etc.) stands for 39% (97.7 per million). As expected, a significant decrease in the offer of equipment is observed when technologically more sophisticated equipment is concerned: magnetic resonance (3.5 per million), gamma

  17. Photoacoustic Determination of Non-radiative Relaxation Time of Absorbing Centers in Maize Seeds

    Science.gov (United States)

    Domínguez-Pacheco, A.; Hernández-Aguilar, C.; Cruz-Orea, A.

    2017-07-01

    Using non-destructive photothermal techniques, it is possible to characterize non-homogenous materials to obtain its optical and thermal properties through photoacoustic spectroscopy (PAS). In photoacoustic (PA) phenomena, there are transient states of thermal excitation, when samples absorb the incident light; these states manifest an excitation process that generates the PA signal, being in direct relation with the non-radiative relaxation times with the sample absorbent centers. The objective of this study was to determine the non-radiative relaxation times associated with different absorbent centers of corn seeds ( Zea mays L.), by using PAS. A frequency scan was done at different wavelengths (350 nm, 470 nm and 650 nm) in order to obtain the non-radiative relaxation times with different types of maize seeds.

  18. Molecular theory for nuclear magnetic relaxation in protein solutions and tissue

    International Nuclear Information System (INIS)

    Kimmich, R.; Nusser, W.; Gneiting, T.

    1990-01-01

    A model theory is presented explaining a series of striking phenomena observed with nuclear magnetic relaxation in protein systems such as solutions or tissue. The frequency, concentration and temperature dependences of proton or deuteron relaxation times of protein solutions and tissue are explained. It is concluded that the translational diffusion of water molecules along the rugged surfaces of proteins and, to a minor degree, protein backbone fluctuations are crucial processes. The rate limiting factor of macromolecular tumbling is assumed to be given by the free water content in a certain analogy to the free-volume model of Cohen ad Turnbull. There are two characteristic water mass fractions indicating the saturation of the hydration shells and the onset of protein tumbling. A closed and relatively simple set of relaxation formulas is presented. The potentially fractal nature of the diffusion of water molecules on the protein surface is discussed. (author). 43 refs.; 4 figs

  19. Multivariate analysis of electrical impedance spectra for relaxed and contracted skeletal muscle

    International Nuclear Information System (INIS)

    Zagar, T; Krizaj, D

    2008-01-01

    Four-electrode impedance spectra of relaxed and contracted muscle biceps brachii were analyzed in an adult human subject over the frequency range from 300 Hz to 75 kHz. A feasibility of the principal component analysis of bioimpedance measurement for the evaluation of skeletal muscle contractile state was examined. The principal components score plots show a data grouping of the impedance spectra from the two muscle groups. The classification was performed using a soft independent modeling of class analogy (SIMCA) method. The data set comprised 32 samples (16 samples of contracted muscle and 16 samples of relaxed muscle). The leave-one-out test of the classification yields about 80% of correctly classified samples (11 samples for contracted and 15 samples for relaxed muscle)

  20. [Transient lower esophageal sphincter relaxation and the related esophageal motor activities].

    Science.gov (United States)

    Han, Seung Hyo; Hong, Su Jin

    2012-03-01

    Transient lower esophageal sphincter (LES) relaxation (TLESR) is defined as LES relaxation without a swallow. TLESRs are observed in both of the normal individuals and the patients with gastroesophageal reflux disorder (GERD). However, TLESR is widely considered as the major mechanism of the GERD. The new equipments such as high resolution manometry and impedance pH study is helped to understand of TLESR and the related esophageal motor activities. The strong longitudinal muscle contraction was observed during development of TLESR. Most of TLESRs are terminated by TLESR related motor events such as primary peristalsis and secondary contractions. The majority of TLESRs are associated with gastroesophageal reflux. Upper esophageal sphincter (UES) contraction is mainly associated with liquid reflux during recumbent position and UES relaxation predominantly related with air reflux during upright position. The frequency of TLESR in GERD patients seems to be not different compared to normal individuals, but the refluxate of GERD patients tend to be more acidic during TLESR.

  1. Atmospheric Wind Relaxations and the Oceanic Response in the California Current Large Marine Ecosystem

    Science.gov (United States)

    Fewings, M. R.; Dorman, C. E.; Washburn, L.; Liu, W.

    2010-12-01

    On the West Coast of North America in summer, episodic relaxation of the upwelling-favorable winds causes warm water to propagate northward from southern to central California, against the prevailing currents [Harms and Winant 1998, Winant et al. 2003, Melton et al. 2009]. Similar wind relaxations are an important characteristic of coastal upwelling ecosystems worldwide. Although these wind relaxations have an important influence on coastal ocean dynamics, no description exists of the regional atmospheric patterns that lead to wind relaxations in southern California, or of the regional ocean response. We use QuikSCAT wind stress, North American Regional Reanalysis atmospheric pressure products, water temperature and velocity from coastal ocean moorings, surface ocean currents from high-frequency radars, and MODIS satellite sea-surface temperature and ocean color images to analyze wind relaxation events and the ocean response. We identify the events based on an empirical index calculated from NDBC buoy winds [Melton et al. 2009]. We describe the regional evolution of the atmosphere from the Gulf of Alaska to Baja California over the few days leading up to wind relaxations, and the coastal ocean temperature, color, and current response off southern and central California. We analyze ~100 wind relaxation events in June-September during the QuikSCAT mission, 1999-2009. Our results indicate south-central California wind relaxations in summer are tied to mid-level atmospheric low-pressure systems that form in the Gulf of Alaska and propagate southeastward over 3-5 days. As the low-pressure systems reach southern California, the atmospheric pressure gradient along the coast weakens, causing the surface wind stress to relax to near zero. The weak wind signal appears first at San Diego and propagates northward. QuikSCAT data indicate the relaxed winds extend over the entire Southern California Bight and up to 200 km offshore of central California. Atmospheric dynamics in

  2. Nuclear spin dominated relaxation of atomic tunneling systems in glasses

    Energy Technology Data Exchange (ETDEWEB)

    Luck, Annina

    2016-11-16

    The measurements performed in this thesis have revealed a non phononic relaxation channel for atomic tunneling systems in glasses at very low temperatures due to the presence of nuclear electric quadrupoles. Dielectric measurements on the multicomponent glasses N-KZFS11 and HY-1, containing {sup 181}Ta and {sup 165}Ho, respectively, that both carry very large nuclear electric quadrupole moments, show a relaxation rate in the kilohertz range, that is constant for temperatures exceeding the nuclear quadrupole splitting of the relevant isotopes. The results are compared to measurements performed on the glasses Herasil and N-BK7 that both contain no large nuclear quadrupole moments. Using three different setups to measure the complex dielectric function, the measurements cover almost eight orders of magnitude in frequency from 60 Hz to 1 GHz and temperatures down to 7.5 mK. This has allowed us a detailed study of the novel effects observed within this thesis and has led to a simplified model explaining the effects of nuclear electric quadrupoles on the behavior of glasses at low temperatures. Numeric calculations based on this model are compared to the measured data.

  3. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  4. Parametric effects of word frequency effect in memory for mixed frequency lists

    OpenAIRE

    Lohnas, Lynn J.; Kahana, Michael J.

    2013-01-01

    The word frequency paradox refers to the finding that low frequency words are better recognized than high frequency words yet high frequency words are better recalled than low frequency words. Rather than comparing separate groups of low and high frequency words, we sought to quantify the functional relation between word frequency and memory performance across the broad range of frequencies typically used in episodic memory experiments. Here we report that both low frequency and high frequenc...

  5. Heteronuclear Adiabatic Relaxation Dispersion (HARD) for quantitative analysis of conformational dynamics in proteins.

    Science.gov (United States)

    Traaseth, Nathaniel J; Chao, Fa-An; Masterson, Larry R; Mangia, Silvia; Garwood, Michael; Michaeli, Shalom; Seelig, Burckhard; Veglia, Gianluigi

    2012-06-01

    NMR relaxation methods probe biomolecular motions over a wide range of timescales. In particular, the rotating frame spin-lock R(1ρ) and Carr-Purcell-Meiboom-Gill (CPMG) R(2) experiments are commonly used to characterize μs to ms dynamics, which play a critical role in enzyme folding and catalysis. In an effort to complement these approaches, we introduced the Heteronuclear Adiabatic Relaxation Dispersion (HARD) method, where dispersion in rotating frame relaxation rate constants (longitudinal R(1ρ) and transverse R(2ρ)) is created by modulating the shape and duration of adiabatic full passage (AFP) pulses. Previously, we showed the ability of the HARD method to detect chemical exchange dynamics in the fast exchange regime (k(ex)∼10(4)-10(5) s(-1)). In this article, we show the sensitivity of the HARD method to slower exchange processes by measuring R(1ρ) and R(2ρ) relaxation rates for two soluble proteins (ubiquitin and 10C RNA ligase). One advantage of the HARD method is its nominal dependence on the applied radio frequency field, which can be leveraged to modulate the dispersion in the relaxation rate constants. In addition, we also include product operator simulations to define the dynamic range of adiabatic R(1ρ) and R(2ρ) that is valid under all exchange regimes. We conclude from both experimental observations and simulations that this method is complementary to CPMG-based and rotating frame spin-lock R(1ρ) experiments to probe conformational exchange dynamics for biomolecules. Finally, this approach is germane to several NMR-active nuclei, where relaxation rates are frequency-offset independent. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. T2 relaxation time analysis in patients with multiple sclerosis: correlation with magnetization transfer ratio

    International Nuclear Information System (INIS)

    Papanikolaou, Nickolas; Papadaki, Eufrosini; Karampekios, Spyros; Maris, Thomas; Prassopoulos, Panos; Gourtsoyiannis, Nicholas; Spilioti, Martha

    2004-01-01

    The aim of the current study was to perform T2 relaxation time measurements in multiple sclerosis (MS) patients and correlate them with magnetization transfer ratio (MTR) measurements, in order to investigate in more detail the various histopathological changes that occur in lesions and normal-appearing white matter (NAWM). A total number of 291 measurements of MTR and T2 relaxation times were performed in 13 MS patients and 10 age-matched healthy volunteers. Measurements concerned MS plaques (105), NAWM (80), and ''dirty'' white matter (DWM; 30), evenly divided between the MS patients, and normal white matter (NWM; 76) in the healthy volunteers. Biexponential T2 relaxation-time analysis was performed, and also possible linearity between MTR and mean T2 relaxation times was evaluated using linear regression analysis in all subgroups. Biexponential relaxation was more pronounced in ''black-hole'' lesions (16.6%) and homogeneous enhancing plaques (10%), whereas DWM, NAWM, and mildly hypointense lesions presented biexponential behavior with a lower frequency(6.6, 5, and 3.1%, respectively). Non-enhancing isointense lesions and normal white matter did not reveal any biexponentional behavior. Linear regression analysis between monoexponential T2 relaxation time and MTR measurements demonstrated excellent correlation for DWM(r=-0.78, p<0.0001), very good correlation for black-hole lesions(r=-0.71, p=0.002), good correlation for isointense lesions(r=-0.60, p=0.005), moderate correlation for mildly hypointense lesions(r=-0.34, p=0.007), and non-significant correlation for homogeneous enhancing plaques, NAWM, and NWM. Biexponential T2 relaxation-time behavior is seen in only very few lesions (mainly on plaques with high degree of demyelination and axonal loss). A strong correlation between MTR and monoexponential T2 values was found in regions where either inflammation or demyelination predominates; however, when both pathological conditions coexist, this linear

  7. Arginase attenuates inhibitory nonadrenergic noncholinergic nerve-induced nitric oxide generation and airway smooth muscle relaxation

    Directory of Open Access Journals (Sweden)

    Meurs Herman

    2005-03-01

    Full Text Available Abstract Background Recent evidence suggests that endogenous arginase activity potentiates airway responsiveness to methacholine by attenuation of agonist-induced nitric oxide (NO production, presumably by competition with epithelial constitutive NO synthase for the common substrate, L-arginine. Using guinea pig tracheal open-ring preparations, we now investigated the involvement of arginase in the modulation of neuronal nitric oxide synthase (nNOS-mediated relaxation induced by inhibitory nonadrenergic noncholinergic (iNANC nerve stimulation. Methods Electrical field stimulation (EFS; 150 mA, 4 ms, 4 s, 0.5 – 16 Hz-induced relaxation was measured in tracheal preparations precontracted to 30% with histamine, in the presence of 1 μM atropine and 3 μM indomethacin. The contribution of NO to the EFS-induced relaxation was assessed by the nonselective NOS inhibitor L-NNA (0.1 mM, while the involvement of arginase activity in the regulation of EFS-induced NO production and relaxation was investigated by the effect of the specific arginase inhibitor nor-NOHA (10 μM. Furthermore, the role of substrate availability to nNOS in EFS-induced relaxation was measured in the presence of various concentrations of exogenous L-arginine. Results EFS induced a frequency-dependent relaxation, ranging from 6.6 ± 0.8% at 0.5 Hz to 74.6 ± 1.2% at 16 Hz, which was inhibited with the NOS inhibitor L-NNA by 78.0 ± 10.5% at 0.5 Hz to 26.7 ± 7.7% at 8 Hz (P Conclusion The results indicate that endogenous arginase activity attenuates iNANC nerve-mediated airway relaxation by inhibition of NO generation, presumably by limiting L-arginine availability to nNOS.

  8. Frequency-dependent complex modulus at the glass transition in Pd40Ni10Cu30P20 bulk amorphous alloys

    International Nuclear Information System (INIS)

    Lee, M.L.; Li, Y.; Feng, Y.P.; Carter, W.C.

    2003-01-01

    We report frequency-dependent measurements of the dynamic elastic modulus of a Pd 40 Cu 30 Ni 10 P 20 bulk amorphous phase near its glass transition temperature. The storage and loss moduli exhibit a structural relaxation similar to those observed by other characterization techniques. Parameters obtained by fitting to the Vogel-Fulcher-Tamman equation and the Kohlrausch-Williams-Watts model exhibit similar behaviors to those other methods

  9. Dynamical relaxation in 2HDM models

    Science.gov (United States)

    Lalak, Zygmunt; Markiewicz, Adam

    2018-03-01

    Dynamical relaxation provides an interesting solution to the hierarchy problem in face of the missing signatures of any new physics in recent experiments. Through a dynamical process taking place in the inflationary phase of the Universe it manages to achieve a small electroweak scale without introducing new states observable in current experiments. Appropriate approximation makes it possible to derive an explicit formula for the final vevs in the double-scanning scenario extended to a model with two Higgs doublets (2HDM). Analysis of the relaxation in the 2HDM confirms that in a general case it is impossible to keep vevs of both scalars small, unless fine-tuning is present or additional symmetries are cast upon the Lagrangian. Within the slightly constrained variant of the 2HDM, where odd powers of the fields’ expectation values are not present (which can be easily enforced by requiring that the doublets have different gauge transformations or by imposing a global symmetry) it is shown that the difference between the vevs of two scalars tends to be proportional to the cutoff. The analysis of the relaxation in 2HDM indicates that in a general case the relaxation would be stopped by the first doublet that gains a vev, with the other one remaining vevless with a mass of the order of the cutoff. This happens to conform with the inert doublet model.

  10. Relaxation of coupled nuclear spin systems

    International Nuclear Information System (INIS)

    Koenigsberger, E.

    1985-05-01

    The subject of the present work is the relaxation behaviour of scalarly coupled spin-1/2 systems. In the theoretical part the semiclassical Redfield equations are used. Dipolar (D), Chemical Shift Anisotropy (CSA) and Random Field (RF) interactions are considered as relaxation mechanisms. Cross correlations of dipolar interactions of different nuclei pairs and those between the D and the CSA mechanisms are important. The model of anisotropic molecular rotational relaxation and the extreme narrowing approximation are used to obtain the spectral density functions. The longitudinal relaxation data are analyzed into normal modes following Werbelow and Grant. The time evolution of normal modes is derived for the AX system with D-CSA cross terms. In the experimental part the hypothesis of dimerization in the cinnamic acid and the methyl cinnamate - AMX systems with DD cross terms - is corroborated by T 1 -time measurements and a calculation of the diffusion constants. In pentachlorobenzene - an AX system - taking into account of D-CSA cross terms enables the complete determination of movements anosotropy and the determination of the sign of the indirect coupling constant 1 Jsub(CH). (G.Q.)

  11. Quantization by stochastic relaxation processes and supersymmetry

    International Nuclear Information System (INIS)

    Kirschner, R.

    1984-01-01

    We show the supersymmetry mechanism resposible for the quantization by stochastic relaxation processes and for the effective cancellation of the additional time dimension against the two Grassmann dimensions. We give a non-perturbative proof of the validity of this quantization procedure. (author)

  12. Charge Relaxation Dynamics of an Electrolytic Nanocapacitor

    Science.gov (United States)

    2015-01-01

    Understanding ion relaxation dynamics in overlapping electric double layers (EDLs) is critical for the development of efficient nanotechnology-based electrochemical energy storage, electrochemomechanical energy conversion, and bioelectrochemical sensing devices as well as the controlled synthesis of nanostructured materials. Here, a lattice Boltzmann (LB) method is employed to simulate an electrolytic nanocapacitor subjected to a step potential at t = 0 for various degrees of EDL overlap, solvent viscosities, ratios of cation-to-anion diffusivity, and electrode separations. The use of a novel continuously varying and Galilean-invariant molecular-speed-dependent relaxation time (MSDRT) with the LB equation recovers a correct microscopic description of the molecular-collision phenomena and enhances the stability of the LB algorithm. Results for large EDL overlaps indicated oscillatory behavior for the ionic current density, in contrast to monotonic relaxation to equilibrium for low EDL overlaps. Further, at low solvent viscosities and large EDL overlaps, anomalous plasmalike spatial oscillations of the electric field were observed that appeared to be purely an effect of nanoscale confinement. Employing MSDRT in our simulations enabled modeling of the fundamental physics of the transient charge relaxation dynamics in electrochemical systems operating away from equilibrium wherein Nernst–Einstein relation is known to be violated. PMID:25678941

  13. Waveform relaxation methods for implicit differential equations

    NARCIS (Netherlands)

    P.J. van der Houwen; W.A. van der Veen

    1996-01-01

    textabstractWe apply a Runge-Kutta-based waveform relaxation method to initial-value problems for implicit differential equations. In the implementation of such methods, a sequence of nonlinear systems has to be solved iteratively in each step of the integration process. The size of these systems

  14. Collection Development: Relaxation & Meditation, September 1, 2010

    Science.gov (United States)

    Lettus, Dodi

    2010-01-01

    One of the first books to document the relationship between stress and physical and emotional health was "The Relaxation Response" by Herbert Benson, M.D., with Miriam Z. Klipper. Originally published in 1975, the book grew out of Benson's observations as a cardiologist and his research as a fellow at Harvard Medical School. Benson's study of…

  15. Stretched Exponential relaxation in pure Se glass

    Science.gov (United States)

    Dash, S.; Ravindren, S.; Boolchand, P.

    A universal feature of glasses is the stretched exponential relaxation, f (t) = exp[ - t / τ ] β . The model of diffusion of excitations to randomly distributed traps in a glass by Phillips1 yields the stretched exponent β = d[d +2] where d, the effective dimensionality. We have measured the enthalpy of relaxation ΔHnr (tw) at Tg of Se glass in modulated DSC experiments as glasses age at 300K and find β = 0.43(2) for tw in the 0 relaxation is a narrowing of the glass transition width from 7.1°C to 1.4°C, and the ΔHnr term increasing from 0.21 cal/gm to 0.92 cal/gm. In bulk GexSe100-x glasses as x increases to 20%, the length of the polymeric Sen chains between the Ge-crosslinks decreases to n = 2. and the striking relaxation effects nearly vanish. J.C. Phillips, Rep.Prog.Phys. 59 , 1133 (1996). Supported by NSF Grant DMR 08-53957.

  16. Non-Arrhenius conductivity in the fast ionic conductor Li0.5La0.5TiO3: Reconciling spin-lattice and electrical-conductivity relaxations

    International Nuclear Information System (INIS)

    Leon, C.; Santamaria, J.; Paris, M.A.; Sanz, J.; Ibarra, J.; Torres, L.M.

    1997-01-01

    Nuclear magnetic resonance and electrical conductivity measurements are conducted to study the dynamics of the ionic diffusion process in the crystalline ionic conductor Li 0.5 La 0.5 TiO 3 . dc conductivity shows a non-Arrhenius temperature dependence, similar to the one recently reported for some ionic conducting glasses. Spin-lattice and conductivity relaxations are analyzed in the same frequency and temperature range in terms of the non-Arrhenius dependence of the correlation time. Both relaxations are then described using a single correlation function of the form f(t)=exp(-(t/τ) β ), with β=0.4 over the whole temperature range. copyright 1997 The American Physical Society

  17. Mars Rover Curriculum: Teacher Self Reporting of Increased Frequency and Confidence in their Science and Language Arts Instruction

    Science.gov (United States)

    Bering, E. A.; Carlson, C.; Nieser, K.; Slagle, E.

    2013-12-01

    The University of Houston is in the process of developing a flexible program that offers children an in-depth educational experience culminating in the design and construction of their own model Mars rover. The program is called the Mars Rover Model Celebration (MRC). It focuses on students, teachers and parents in grades 3-8. Students design and build a model of a Mars rover to carry out a student selected science mission on the surface of Mars. A total of 65 Mars Rover teachers from the 2012-2013 cohort were invited to complete the Mars Rover Teacher Evaluation Survey. The survey was administered online and could be taken at the convenience of the participant. In total, 29 teachers participated in the survey. Teachers were asked to rate their current level of confidence in their ability to teach specific topics within the Earth and Life Science realms, as well as their confidence in their ability to implement teaching strategies with their students. In addition, they were asked to rate the degree to which they felt their confidence increased in the past year as a result of their participation in the MRC program. The majority of teachers (81-90%) felt somewhat to very confident in their ability to effectively teach concepts related to earth and life sciences to their students. In addition, many of the teachers felt that their confidence in teaching these concepts increased somewhat to quite a bit as a result of their participation in the MRC program (54-88%). The most striking increase in this area was the reported 48% of teachers who felt their confidence in teaching 'Earth and the solar system and universe' increased 'Quite a bit' as a result of their participation in the MRC program. The vast majority of teachers (86-100%) felt somewhat to very confident in their ability to effectively implement all of the listed teaching strategies. In addition, the vast majority reported believing that their confidence increased somewhat to quite a bit as a result of their

  18. TFTR Ion Cyclotron Range of Frequencies (ICRF) experimental data analysis collaboration. Annual progress report, December 1, 1993--November 30, 1994

    International Nuclear Information System (INIS)

    Sharer, J.E.; Bettenhausen, M.; Lam, N.; Sund, R.

    1994-08-01

    The research performed under this grant during the past year has concentrated on coupling, heating, and current drive issues for TFTR. The authors have developed a code and submitted for publication a open-quotes 3-Dclose quotes coupling analysis of the TFIR ICRF cavity-backed coil antennas to plasma edge profiles including the Faraday shield blade angle and fast wave coupling for heating and current drive. They have also carried out TFTR ICRF full-wave field solutions and heating analyses for the second harmonic tritium supershot, and the effects of fusion alpha particle and tritium ion tail populations on the ICRF absorption. They have also published a paper on the effects of alpha particle absorption on fundamental deuterium ion cyclotron absorption incorporating self-consistent deuterium tails and fusion reactivity. Research progress, publications, and conference presentations are summarized in this report

  19. CUSTOM RELAXATION INDUCED IMPURITY PHOTOCONDUCTIVITY IN THE UNITED AII BVI and AIII BV

    Directory of Open Access Journals (Sweden)

    L. B. Atlukhanova

    2016-01-01

    Full Text Available Two types of non-standard relaxation induced impurity photoconductivity (IIP observed in photoconductors CdS, ZnSe, GaAs and others, depending on the kinetic characteristics of the traps are described. In one case, at the stage of post flashing monotonic decay which is typical for relaxation associated with slow traps (the ratio of the speed of the electron capture to the recombination rate (R << 1, the photo response is experiencing vibrations of low frequency (f =0.03-0.3Hz. Relaxation of the second type characterized by rapid photoelectric traps (R >> 1: measurement alternating signal (f > 20 Hz relaxation curves take the form of curves usual impurity photoconductivity. Electronic processes responsible for relaxation of non-standard IIP are analyzed. For example, fast-centers, which include the characteristic AIIBVI donor Agi0, for the first time in semiconductors experimentally, investigated the dependence of the cross section of electron capture by traps energy released during localization.

  20. Electronic relaxation of deep bulk trap and interface state in ZnO ceramics

    International Nuclear Information System (INIS)

    Yang Yan; Li Sheng-Tao; Ding Can; Cheng Peng-Fei

    2011-01-01

    This paper investigates the electronic relaxation of deep bulk trap and interface state in ZnO ceramics based on dielectric spectra measured in a wide range of temperature, frequency and bias, in addition to the steady state response. It discusses the nature of net current flowing over the barrier affected by interface state, and then obtains temperature-dependent barrier height by approximate calculation from steady I—V (current—voltage) characteristics. Additional conductance and capacitance arising from deep bulk trap relaxation are calculated based on the displacement of the cross point between deep bulk trap and Fermi level under small AC signal. From the resonances due to deep bulk trap relaxation on dielectric spectra, the activation energies are obtained as 0.22 eV and 0.35 eV, which are consistent with the electronic levels of the main defect interstitial Zn and vacancy oxygen in the depletion layer. Under moderate bias, another resonance due to interface relaxation is shown on the dielectric spectra. The DC-like conductance is also observed in high temperature region on dielectric spectra, and the activation energy is much smaller than the barrier height in steady state condition, which is attributed to the displacement current coming from the shallow bulk trap relaxation or other factors. (fluids, plasmas and electric discharges)

  1. NMR relaxation rate in quasi one-dimensional antiferromagnets

    Science.gov (United States)

    Capponi, Sylvain; Dupont, Maxime; Laflorencie, Nicolas; Sengupta, Pinaki; Shao, Hui; Sandvik, Anders W.

    We compare results of different numerical approaches to compute the NMR relaxation rate 1 /T1 in quasi one-dimensional (1d) antiferromagnets. In the purely 1d regime, recent numerical simulations using DMRG have provided the full crossover behavior from classical regime at high temperature to universal Tomonaga-Luttinger liquid at low-energy (in the gapless case) or activated behavior (in the gapped case). For quasi 1d models, we can use mean-field approaches to reduce the problem to a 1d one that can be studied using DMRG. But in some cases, we can also simulate the full microscopic model using quantum Monte-Carlo techniques. This allows to compute dynamical correlations in imaginary time and we will discuss recent advances to perform stochastic analytic continuation to get real frequency spectra. Finally, we connect our results to experiments on various quasi 1d materials.

  2. Plasma density measurements from the GEOS-1 relaxation sounder

    International Nuclear Information System (INIS)

    Etcheto, J.; Bloch, J.J.

    1978-01-01

    The relaxation sounder uses the characteristics of the propagation of radiowaves to sound the plasma surrounding the spacecraft. It determines, in particular, the plasma frequency, which gives the electron density. Measurements over the whole dayside of the magnetosphere, from the evening to the night sectors, are now available. The behaviour of the plasma resonance depends on local time, the nighttime echoes being generally weaker. Density measurements thus obtained are shown and discussed in the context of what is presently known about the plasma distribution in the magnetosphere. In particular, the density around apogee is studied as a function of magnetic activity. On the dayside, it appears to vary between a few and a few tens of electrons per cubic centimeter. The evolution of the density profile for several consecutive days is studied and interpreted tracing back the drift of the particles. (Auth.)

  3. Spin Relaxation and Manipulation in Spin-orbit Qubits

    Science.gov (United States)

    Borhani, Massoud; Hu, Xuedong

    2012-02-01

    We derive a generalized form of the Electric Dipole Spin Resonance (EDSR) Hamiltonian in the presence of the spin-orbit interaction for single spins in an elliptic quantum dot (QD) subject to an arbitrary (in both direction and magnitude) applied magnetic field. We predict a nonlinear behavior of the Rabi frequency as a function of the magnetic field for sufficiently large Zeeman energies, and present a microscopic expression for the anisotropic electron g-tensor. Similarly, an EDSR Hamiltonian is devised for two spins confined in a double quantum dot (DQD). Finally, we calculate two-electron-spin relaxation rates due to phonon emission, for both in-plane and perpendicular magnetic fields. Our results have immediate applications to current EDSR experiments on nanowire QDs, g-factor optimization of confined carriers, and spin decay measurements in DQD spin-orbit qubits.

  4. Frequency Synthesiser

    NARCIS (Netherlands)

    Drago, Salvatore; Sebastiano, Fabio; Leenaerts, Dominicus M.W.; Breems, Lucien J.; Nauta, Bram

    2016-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  5. Frequency synthesiser

    NARCIS (Netherlands)

    Drago, S.; Sebastiano, Fabio; Leenaerts, Dominicus Martinus Wilhelmus; Breems, Lucien Johannes; Nauta, Bram

    2010-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  6. Electron spin-lattice relaxation in fractals

    International Nuclear Information System (INIS)

    Shrivastava, K.N.

    1986-08-01

    We have developed the theory of the spin-fracton interaction for paramagnetic ions in fractal structures. The interaction is exponentially damped by the self-similarity length of the fractal and by the range dimensionality d Φ . The relaxation time of the spin due to the absorption and emission of the fracton has been calculated for a general dimensionality called the Raman dimensionality d R , which for the fractons differs from the Hausdorff (fractal) dimensionality, D, as well as from the Euclidean dimensionality, d. The exponent of the energy level separation in the relaxation rate varies with d R d Φ /D. We have calculated the spin relaxation rate due to a new type of Raman process in which one fracton is absorbed to affect a spin transition from one electronic level to another and later another fracton is emitted along with a spin transition such that the difference in the energies of the two fractons is equal to the electronic energy level separation. The temperature and the dimensionality dependence of such a process has been found in several approximations. In one of the approximations where the van Vleck relaxation rate for a spin in a crystal is known to vary with temperature as T 9 , our calculated variation for fractals turns out to be T 6.6 , whereas the experimental value for Fe 3+ in frozen solutions of myoglobin azide is T 6.3 . Since we used d R =4/3 and the fracton range dimensionality d Φ =D/1.8, we expect to measure the dimensionalities of the problem by measuring the temperature dependence of the relaxation times. We have also calculated the shift of the paramagnetic resonance transition for a spin in a fractal for general dimensionalities. (author)

  7. The WHISPER Relaxation Sounder and the CLUSTER Active Archive

    Science.gov (United States)

    Trotignon, J. G.; Décréau, P. M. E.; Rauch, J. L.; Vallières, X.; Rochel, A.; Kougblénou, S.; Lointier, G.; Facskó, G.; Canu, P.; Darrouzet, F.; Masson, A.

    The Waves of HIgh frequency and Sounder for Probing of Electron density by Relaxation (WHISPER) instrument is part of the Wave Experiment Consortium (WEC) of the CLUSTER mission. With the help of the long double sphere antennae of the Electric Field and Wave (EFW) instrument and the Digital Wave Processor (DWP), it delivers active (sounding) and natural (transmitter off) electric field spectra, respectively from 4 to 82 kHz, and from 2 to 80 kHz. These frequency ranges have been chosen to include the electron plasma frequency, which is closely related to the total electron density, in most of the regions encountered by the CLUSTER spacecraft. Presented here is an overview of the WHISPER data products available in the CLUSTER Active Archive (CAA). The instrument and its performance are first recalled. The way the WHISPER products are obtained is then described, with particular attention being paid to the density determination. Both sounding and natural measurements are commonly used in this process, which depends on the ambient plasma regime. This is illustrated using drawings similar to the Bryant plots commonly used in the CLUSTER master science plan. These give a clear overview of typical density values and the parts of the orbits where they are obtained. More information on the applied software or on the quality/reliability of the density determination can also be highlighted.

  8. Relaxant effects of Ocimum basilicum on guinea pig tracheal chains and its possible mechanism(s

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Boskabady

    2005-01-01

    Full Text Available Therapeutic effects of Ocimum basilicum on respiratory diseases especially dyspnea have been reported in Iranian ancient medical books. In the present study, the relaxant effects of macerated and soxhlet extracts of this plant on tracheal chains of guinea pigs were evaluated. The relaxant effects of 4 cumulative concentrations of macerated and soxhlet extracts (0.25, 0.5, 0.75 and 1.0 W/V in comparison with saline as negative control and 4 cumulative concentrations of theophylline (0.25, 0.5, 0.75, and 1.0 mM as positive control were examined on precontracted tracheal chains of two groups of 6 guinea pig by 60 mM KCl (group 1 and 10 µM methacholine (group 2. Decrease in contractile tone of tracheal chains was considered as relaxant effect. In group 1 experiments only the last two higher concentrations of theophylline showed significant relaxant effect compared to that of saline (p<0.001 for both concentrations, which were significantly greater than those of macerated and soxhlet extracts (p<0.001 for all cases and in group 2 experiments both macerated and soxhlet extracts showed concentrationdependent relaxant effects compared to that of saline (p<0.05 to p<0.001 for both extracts. There were significant differences between the relaxant effects of both extracts with those of theophylline in group 2 experiments (p<0.01 to p<0.001. The relaxant effects of macerated and soxhlet extracts in group 1 were significantly lower than those of groups 2. These results showed a potent relaxant effect of Ocimum basilicum on tracheal chains of guinea pigs which were lower than theophylline at concentrations used.

  9. Hydrogen bond network relaxation in aqueous polyelectrolyte solutions: the effect of temperature

    International Nuclear Information System (INIS)

    Sarti, S; Bordi, F; Truzzolillo, D

    2012-01-01

    Dielectric spectroscopy data over the range 100 MHz-40 GHz allow for a reliable analysis of two of the major relaxation phenomena for polyelectrolytes (PE) in water. Within this range, the dielectric relaxation of pure water is dominated by a near-Debye process at ν = 18.5 GHz corresponding to a relaxation time of τ = 8.4 ps at 25 °C. This mode is commonly attributed to the cooperative relaxation specific to liquids forming a hydrogen bond network (HBN) and arising from long range H-bond-mediated dipole-dipole interactions. The presence of charged polymers in water partially modifies the dielectric characteristics of the orientational water molecule relaxation due to a change of the dielectric constant of water surrounding the charges on the polyion chain. We report experimental results on the effect of the presence of a standard flexible polyelectrolyte (sodium polyacrylate) on the HBN relaxation in water for different temperatures, showing that the HBN relaxation time does not change by increasing the polyelectrolyte density in water, even if relatively high concentrations are reached (0.02 monomol l -1 ≤ C ≤ 0.4 monomol l -1 ). We also find that the effect of PE addition on the HBN relaxation is not even a broadening of its distribution, rather a decrease of the spectral weight that goes beyond the pure volume fraction effect. This extra decrease is larger at low T and less evident at high T, supporting the idea that the correlation length of the water is less affected by the presence of charged flexible chains at high temperatures. (paper)

  10. Radiation-induced colon cancer with high frequency microsatellite instability (MSI-H), report of a case

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Masami; Ueno, Masashi; Koizumi, Koichi [Japanese Foundation for Cancer Research, Tokyo (Japan). Hospital] [and others

    2002-07-01

    We report a 67-year-old female with radiation-induced colon cancer which developed 23 years after radiation therapy for cancer of the endometrium. She was strongly suspected to be a case of hereditary nonpolyposis colorectal cancer (HNPCC) due to her clinical manifestations, i.e. metachronous multiple cancer developed in the endometrium and colon. MSI test and immunohistochemistry for mismatch repair (MMR) proteins revealed that MSI was highly positive and expression of hMSH2 was lost in the colon cancers. Further, on examining the genetic change, the point mutation, ACG{yields}ATG, responsible for amino acid change, was detected in codon8 (exon1) of the hMSH2 gene. The change, however, could be a polymorphism of this gene and further analyses were necessitated to confirm the genetic background for HNPCC. Interestingly, three cancers with adenoma were located in the mucosa of radiation colitis, in which several atypical glands were also found. This is the only case of radiation-induced colorectal cancer with MSI-H in our hospital. Because of our previous studies, we believe that the genetic pathway in carcinogenesis of the radiation-induced colon cancer is different from that of HNPCC, despite their having several kinds of clinical and pathological features in common. (author)

  11. Radiation-induced colon cancer with high frequency microsatellite instability (MSI-H), report of a case

    International Nuclear Information System (INIS)

    Arai, Masami; Ueno, Masashi; Koizumi, Koichi

    2002-01-01

    We report a 67-year-old female with radiation-induced colon cancer which developed 23 years after radiation therapy for cancer of the endometrium. She was strongly suspected to be a case of hereditary nonpolyposis colorectal cancer (HNPCC) due to her clinical manifestations, i.e. metachronous multiple cancer developed in the endometrium and colon. MSI test and immunohistochemistry for mismatch repair (MMR) proteins revealed that MSI was highly positive and expression of hMSH2 was lost in the colon cancers. Further, on examining the genetic change, the point mutation, ACG→ATG, responsible for amino acid change, was detected in codon8 (exon1) of the hMSH2 gene. The change, however, could be a polymorphism of this gene and further analyses were necessitated to confirm the genetic background for HNPCC. Interestingly, three cancers with adenoma were located in the mucosa of radiation colitis, in which several atypical glands were also found. This is the only case of radiation-induced colorectal cancer with MSI-H in our hospital. Because of our previous studies, we believe that the genetic pathway in carcinogenesis of the radiation-induced colon cancer is different from that of HNPCC, despite their having several kinds of clinical and pathological features in common. (author)

  12. ENERGY RELAXATION OF HELIUM ATOMS IN ASTROPHYSICAL GASES

    International Nuclear Information System (INIS)

    Lewkow, N. R.; Kharchenko, V.; Zhang, P.

    2012-01-01

    We report accurate parameters describing energy relaxation of He atoms in atomic gases, important for astrophysics and atmospheric science. Collisional energy exchange between helium atoms and atomic constituents of the interstellar gas, heliosphere, and upper planetary atmosphere has been investigated. Energy transfer rates, number of collisions required for thermalization, energy distributions of recoil atoms, and other major parameters of energy relaxation for fast He atoms in thermal H, He, and O gases have been computed in a broad interval of energies from 10 meV to 10 keV. This energy interval is important for astrophysical applications involving the energy deposition of energetic atoms and ions into atmospheres of planets and exoplanets, atmospheric evolution, and analysis of non-equilibrium processes in the interstellar gas and heliosphere. Angular- and energy-dependent cross sections, required for an accurate description of the momentum-energy transfer, are obtained using ab initio interaction potentials and quantum mechanical calculations for scattering processes. Calculation methods used include partial wave analysis for collisional energies below 2 keV and the eikonal approximation at energies higher than 100 eV, keeping a significant energy region of overlap, 0.1-2 keV, between these two methods for their mutual verification. The partial wave method and the eikonal approximation excellently match results obtained with each other as well as experimental data, providing reliable cross sections in the astrophysically important interval of energies from 10 meV to 10 keV. Analytical formulae, interpolating obtained energy- and angular-dependent cross sections, are presented to simplify potential applications of the reported database. Thermalization of fast He atoms in the interstellar gas and energy relaxation of hot He and O atoms in the upper atmosphere of Mars are considered as illustrative examples of potential applications of the new database.

  13. Strain modulations as a mechanism to reduce stress relaxation in laryngeal tissues.

    Science.gov (United States)

    Hunter, Eric J; Siegmund, Thomas; Chan, Roger W

    2014-01-01

    Vocal fold tissues in animal and human species undergo deformation processes at several types of loading rates: a slow strain involved in vocal fold posturing (on the order of 1 Hz or so), cyclic and faster posturing often found in speech tasks or vocal embellishment (1-10 Hz), and shear strain associated with vocal fold vibration during phonation (100 Hz and higher). Relevant to these deformation patterns are the viscous properties of laryngeal tissues, which exhibit non-linear stress relaxation and recovery. In the current study, a large strain time-dependent constitutive model of human vocal fold tissue is used to investigate effects of phonatory posturing cyclic strain in the range of 1 Hz to 10 Hz. Tissue data for two subjects are considered and used to contrast the potential effects of age. Results suggest that modulation frequency and extent (amplitude), as well as the amount of vocal fold overall strain, all affect the change in stress relaxation with modulation added. Generally, the vocal fold cover reduces the rate of relaxation while the opposite is true for the vocal ligament. Further, higher modulation frequencies appear to reduce the rate of relaxation, primarily affecting the ligament. The potential benefits of cyclic strain, often found in vibrato (around 5 Hz modulation) and intonational inflection, are discussed in terms of vocal effort and vocal pitch maintenance. Additionally, elderly tissue appears to not exhibit these benefits to modulation. The exacerbating effect such modulations may have on certain voice disorders, such as muscle tension dysphonia, are explored.

  14. Distinct mechanisms of relaxation to bioactive components from chamomile species in porcine isolated blood vessels

    International Nuclear Information System (INIS)

    Roberts, R.E.; Allen, S.; Chang, A.P.Y.; Henderson, H.; Hobson, G.C.; Karania, B.; Morgan, K.N.; Pek, A.S.Y.; Raghvani, K.; Shee, C.Y.; Shikotra, J.; Street, E.; Abbas, Z.; Ellis, K.; Heer, J.K.; Alexander, S.P.H.

    2013-01-01

    German chamomile (Matricaria recutita L.), a widely-used herbal medicine, has been reported to have a wide range of biological effects, including smooth muscle relaxation. The aim of this study was to compare the effects of representative compounds from chamomile (apigenin, luteolin, (−)-α-bisabolol, farnesene, umbelliferone; 3–30 μM) on vascular tone using porcine coronary and splenic arteries mounted for isometric tension recording in isolated tissue baths and precontracted with the thromboxane-mimetic U46619. Apigenin, luteolin, and (−)-α-bisabolol produced slow, concentration-dependent relaxations in both the coronary and splenic arteries that were not blocked by inhibition of nitric oxide synthase or potassium channels. Removal of extracellular calcium inhibited the relaxations to all three compounds, and these compounds also inhibited calcium re-addition-evoked contractions, indicating that the relaxation response may be mediated through inhibition of calcium influx. Apigenin and luteolin, but not (−)-α-bisabolol, enhanced the relaxation to the nitric oxide donor sodium nitroprusside, indicating that apigenin and luteolin may act to regulate cyclic GMP levels. Umbelliferone produced a rapid, transient relaxation in the splenic artery, but not the coronary artery, that was inhibited by L-NAME and removal of the endothelium, suggesting an influence on nitric oxide production. Farnesene, at concentrations up to 30 μM, was without effect in either blood vessel. In conclusion, hydroxylated compounds (apigenin, luteolin and (−)-α-bisabolol) found in chamomile all caused a slow relaxation of isolated blood vessels through an effect on calcium influx. Umbelliferone, on the other hand, produced a rapid, transient relaxation dependent upon release of nitric oxide from the endothelium. - Highlights: • Apigenin, luteolin, and (-)-α-bisabolol are present in chamomile. • They produced slow, concentration-dependent relaxations in arteries. • These

  15. Distinct mechanisms of relaxation to bioactive components from chamomile species in porcine isolated blood vessels

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, R.E., E-mail: Richard.roberts@nottingham.ac.uk; Allen, S.; Chang, A.P.Y.; Henderson, H.; Hobson, G.C.; Karania, B.; Morgan, K.N.; Pek, A.S.Y.; Raghvani, K.; Shee, C.Y.; Shikotra, J.; Street, E.; Abbas, Z.; Ellis, K.; Heer, J.K.; Alexander, S.P.H., E-mail: steve.alexander@nottingham.ac.uk

    2013-11-01

    German chamomile (Matricaria recutita L.), a widely-used herbal medicine, has been reported to have a wide range of biological effects, including smooth muscle relaxation. The aim of this study was to compare the effects of representative compounds from chamomile (apigenin, luteolin, (−)-α-bisabolol, farnesene, umbelliferone; 3–30 μM) on vascular tone using porcine coronary and splenic arteries mounted for isometric tension recording in isolated tissue baths and precontracted with the thromboxane-mimetic U46619. Apigenin, luteolin, and (−)-α-bisabolol produced slow, concentration-dependent relaxations in both the coronary and splenic arteries that were not blocked by inhibition of nitric oxide synthase or potassium channels. Removal of extracellular calcium inhibited the relaxations to all three compounds, and these compounds also inhibited calcium re-addition-evoked contractions, indicating that the relaxation response may be mediated through inhibition of calcium influx. Apigenin and luteolin, but not (−)-α-bisabolol, enhanced the relaxation to the nitric oxide donor sodium nitroprusside, indicating that apigenin and luteolin may act to regulate cyclic GMP levels. Umbelliferone produced a rapid, transient relaxation in the splenic artery, but not the coronary artery, that was inhibited by L-NAME and removal of the endothelium, suggesting an influence on nitric oxide production. Farnesene, at concentrations up to 30 μM, was without effect in either blood vessel. In conclusion, hydroxylated compounds (apigenin, luteolin and (−)-α-bisabolol) found in chamomile all caused a slow relaxation of isolated blood vessels through an effect on calcium influx. Umbelliferone, on the other hand, produced a rapid, transient relaxation dependent upon release of nitric oxide from the endothelium. - Highlights: • Apigenin, luteolin, and (-)-α-bisabolol are present in chamomile. • They produced slow, concentration-dependent relaxations in arteries. • These

  16. Transport and relaxation properties of superfluid 3He. I. Kinetic equation and Bogoliubov quasiparticle relaxation rate

    International Nuclear Information System (INIS)

    Einzel, D.; Woelfle, P.

    1978-01-01

    The kinetic equation for Bogoliubov quasiparticles for both the A and B phases of superfluid 3 He is derived from the general matrix kinetic equation. A condensed expression for the exact spin-symmetric collision integral is given. The quasiparticle relaxation rate is calculated for the BW state using the s--p approximation for the quasiparticle scattering amplitude. By using the results for the quasiparticle relaxation rate, the mean free path of Bogoliubov quasiparticles is calculated for all temperatures

  17. Effect of guided relaxation and imagery on falls self-efficacy: a randomized controlled trial.

    Science.gov (United States)

    Kim, Bang Hyun; Newton, Roberta A; Sachs, Michael L; Glutting, Joseph J; Glanz, Karen

    2012-06-01

    To examine the effects of guided relaxation and imagery (GRI) on improvement in falls self-efficacy in older adults who report having a fear of falling. Randomized, controlled trial with allocation to GRI or guided relaxation with music of choice. General community. Ninety-one men and women aged 60 to 92. Participants were randomized to listen to a GRI audio compact disk (intervention group) or a guided relaxation audio compact disk and music of choice (control group) twice a week for 6 weeks for 10 minutes per session. Primary outcome measure was the Short Falls Efficacy Scale-International (FES-I). Secondary outcome measures were the Leisure Time Exercise Questionnaire (LTEQ) and the Timed Up and Go (TUG) mobility test. GRI participants reported greater improvements on the Short FES-I (P = .002) and LTEQ (P = .001) scores and shorter time on the TUG (P = .002) than the guided relaxation and music-of-choice group. GRI was more effective at increasing falls self-efficacy and self-reported leisure time exercise and reducing times on a simple mobility test than was guided relaxation with music of choice. GRI is an effective, simple, low-cost tool for older adults to improve falls self-efficacy and leisure time exercise behaviors. © 2012, Copyright the Authors Journal compilation © 2012, The American Geriatrics Society.

  18. Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 108 2

    Science.gov (United States)

    Valdez, A.

    2000-01-01

    This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1 SIN 108, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

  19. Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 109

    Science.gov (United States)

    Valdez, A.

    2000-01-01

    This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 109, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

  20. Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A2, S/N 108, 08

    Science.gov (United States)

    Valdez, A.

    2000-01-01

    This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A2, S/N 108, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

  1. Neuropathic pain: transcranial electric motor cortex stimulation using high frequency random noise. Case report of a novel treatment

    Directory of Open Access Journals (Sweden)

    Alm PA

    2013-06-01

    Full Text Available Per A Alm, Karolina DreimanisDepartment of Neuroscience, Uppsala University, Uppsala, SwedenObjectives: Electric motor cortex stimulation has been reported to be effective for many cases of neuropathic pain, in the form of epidural stimulation or transcranial direct current stimulation (tDCS. A novel technique is transcranial random noise stimulation (tRNS, which increases the cortical excitability irrespective of the orientation of the current. The aim of this study was to investigate the effect of tRNS on neuropathic pain in a small number of subjects, and in a case study explore the effects of different stimulation parameters and the long-term stability of treatment effects.Methods: The study was divided into three phases: (1 a double-blind 100–600 Hz, varying from 0.5 to 10 minutes and from 50 to 1500 µA, at intervals ranging from daily to fortnightly.crossover study, with four subjects; (2 a double-blind extended case study with one responder; and (3 open continued treatment. The motor cortex stimulation consisted of alternating current random noise (100–600 Hz, varying from 0.5 to 10 minutes and from 50 to 1500 μA, at intervals ranging from daily to fortnightly.Results: One out of four participants showed a strong positive effect (also compared with direct-current-sham, P = 0.006. Unexpectedly, this effect was shown to occur also for very weak (100 µA, P = 0.048 and brief (0.5 minutes, P = 0.028 stimulation. The effect was largest during the first month, but remained at a highly motivating level for the patient after 6 months.Discussion: The study suggests that tRNS may be an effective treatment for some cases of neuropathic pain. An important result was the indication that even low levels of stimulation may have substantial effects.Keywords: neuropathic pain, central pain, transcranial direct current stimulation, motor cortex stimulation, random noise stimulation

  2. Dielectric measurements on PWB materials at microwave frequencies

    Indian Academy of Sciences (India)

    Unknown

    the angular frequency and c0 the velocity of light, c the thickness of the ... Dielectric parameters, absorption index and refractive index for pure PSF and pure PMMA at 8⋅92 GHz frequency and at 35°C temperature. Dielectric. Dielectric. Loss. Relaxation. Conductivity Absorption. Refractive. Thickness, constant loss tangent.

  3. Proton NMR relaxivity of blood samples in the presence of some gadolinium and dysprosium compounds

    International Nuclear Information System (INIS)

    Coroiu, I.; Darabont, Al.; Bogdan, M.

    1999-01-01

    The use of some new compounds in MRI tissue and blood characterisation based on nuclear spin relaxation time measurements cannot be sustained until the molecular sources of these variations are understood. Tissues and blood are complex molecular systems with complex NMR properties. A better comprehension of the molecular basis of relaxation offers the possibility to predict the changes expected for a given pathology. The purpose of this contribution is to evidence the different relaxation characteristics of some gadolinium and dysprosium compounds in the presence and absence of the blood and to give a possible explanation about the molecular processes that cause occurrence of changes. Some gadolinium and dysprosium compounds such as: Gd-CIT (gadolinium citrate), Dy-DTPA (DTPA-diethylenetriamine pentaacetic acid), iron oxide - gadolinium oxide (or dysprosium oxide)- dextran complexes were prepared. The longitudinal T 1 -1 and transverse T 2 -1 'relaxation rates' measurements have been carried out as a function of molar concentrations. All measurements have been made at room temperature (about 25 deg.C) and the proton Larmor frequency ν o = 90 MHz. The pulsed NMR spectrometer utilised was a commercial Bruker SXP4/100 spectrometer. Transverse relaxation rate measurements have been made using the Carr-Purcell method, while longitudinal relaxation rate measurements using the inversion recovery pulse sequence, 180 angle-τ-90 angle. The accuracy was about 2-3% for the longitudinal relaxation rates and about 5-7% for the transverse relaxation rates. R 1 and R 2 relaxivities, in mM -1 s -1 were determined from the least square determination of the slopes of plots 1/T 1,2 versus compound molar concentration, using at least five independent measurements at several concentrations between 0 and 2 mM. Increased R 2 relaxivity observed for dysprosium compounds in the blood presence can be explained by PRE effect. The largest gain in R 2 relaxivity seems to imply a noncovalent

  4. Correlation between structural relaxation enthalpy and superconducting properties of amorphous Zr70Cu30 and Zr70Ni30 alloys

    International Nuclear Information System (INIS)

    Inoue, A.; Matsuzaki, K.; Toyota, N.; Chen, H.S.; Masumoto, T.; Fukase, T.

    1985-01-01

    The anneal-induced change in the superconducting properties together with the irrecoverable relaxation enthalpy (ΔHsub(i,exo)) and recoverable relaxation enthalpy (ΔHsub(r,endo)) of amorphous Zr 70 Cu 30 and Zr 70 Ni 30 alloys was examined. The increase in ΔHsub(i,exo) and the degradation of Tsub(c) progress logarithmically with annealing time tsub(a) in a temperature range of 373 to 523 K. The activation energy and the attempted frequency were respectively estimated to be 1.5 eV and 6.6 x 10 13 sec -1 for the increase in ΔHsub(i,exo) and 1.5 eV and 1.9 x 10 14 sec -1 for the degradation of Tsub(c). The recoverable structure relaxation exerts little effect on Tsub(c). Based on the agreement between the kinetic parameters for the changes of ΔHsub(i,exo) and Tsub(c), it appears that the degradation of Tsub(c) on annealing is associated with the irrecoverable structural relaxation as a result of the annihilation of frozen-in defects and the topological and compositional atomic rearrangement. The values of the attempted frequency being of the order of Debye frequency suggest that the irrecoverable structural relaxation processes occur more or less independently from each other. (author)

  5. Vibrational Energy Relaxation in Water-Acetonitrile Mixtures

    NARCIS (Netherlands)

    Cringus, Dan; Yeremenko, Sergey; Pshenichnikov, Maxim S.; Wiersma, Douwe A.; Kobayashi, Takayoshi; Kobayashi, Tetsuro; Nelson, Keith A.; Okada, Tadashi; Silvestri, Sandro De

    2004-01-01

    IR pump-probe spectroscopy is used to study the effect of hydrogen bonding on the vibrational energy relaxation pathways. Hydrogen bonding accelerates the population relaxation from 12ps in diluted acetonitrile solution to 700fs in bulk water.

  6. Exploiting Sparsity in SDP Relaxation for Sensor Network Localization

    NARCIS (Netherlands)

    S. Kim (Sunyoung); M. Kojima; H. Waki (Hayato)

    2008-01-01

    htmlabstract A sensor network localization problem can be formulated as a quadratic optimization problem (QOP). For quadratic optimization problems, semidefinite programming (SDP) relaxation by Lasserre with relaxation order 1 for general polynomial optimization problems (POPs) is known to be

  7. Exploiting Sparsity in SDP Relaxation for Sensor Network Localization

    NARCIS (Netherlands)

    S. Kim (Sunyoung); M. Kojima; H. Waki (Hayato)

    2009-01-01

    htmlabstract A sensor network localization problem can be formulated as a quadratic optimization problem (QOP). For quadratic optimization problems, semidefinite programming (SDP) relaxation by Lasserre with relaxation order 1 for general polynomial optimization problems (POPs) is known to be

  8. Experimental, theoretical and computational study of frequency upshift of electromagnetic radiation using plasma techniques. Final technical report, January 14, 1991--January 14, 1995

    International Nuclear Information System (INIS)

    Joshi, C.

    1997-01-01

    The final report for the project is comprised of the PhD thesis of Richard L. Savage, Jr entitled: 'Frequency Upshifting of Electromagnetic Radiation via an Underdense Relativistic Ionization Front.' An underdense, relativistically propagating ionization front has been utilized to upshift the frequency of an impinging electromagnetic wave from 35 GHz to more than 173 GHz in a continuously tunable fashion. The source radiation interacted with the ionization front inside a metallic waveguide. The front, simply a moving boundary between ionized and neutral gas, was created as a short, intense pulse of ionizing laser radiation propagated through the gas-filled waveguide. In 1991, W.B. Mori showed theoretically that large upshifts are possible using underdense ionization fronts (underdense implies that the plasma density is lower than that required to reflect the source radiation), where the source wave is transmitted through the plasma/neutral boundary. The authors have extrapolated Mori's analysis to interactions within a waveguide. This is a new technique for generating high-power, short-pulse, tunable radiation, and has potential applications in areas such as time-resolved microwave spectroscopy, plasma diagnostics, and remote sensing

  9. Frequency Response Analysis Tool

    Energy Technology Data Exchange (ETDEWEB)

    Etingov, Pavel V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kosterev, Dmitry [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dai, T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-01

    Frequency response has received a lot of attention in recent years at the national level, which culminated in the development and approval of North American Electricity Reliability Corporation (NERC) BAL-003-1 Frequency Response and Frequency Bias Setting Reliability Standard. This report is prepared to describe the details of the work conducted by Pacific Northwest National Laboratory (PNNL) in collaboration with the Bonneville Power Administration and Western Electricity Coordinating Council (WECC) Joint Synchronized Information Subcommittee (JSIS) to develop a frequency response analysis tool (FRAT). The document provides the details on the methodology and main features of the FRAT. The tool manages the database of under-frequency events and calculates the frequency response baseline. Frequency response calculations are consistent with frequency response measure (FRM) in NERC BAL-003-1 for an interconnection and balancing authority. The FRAT can use both phasor measurement unit (PMU) data, where available, and supervisory control and data acquisition (SCADA) data. The tool is also capable of automatically generating NERC Frequency Response Survey (FRS) forms required by BAL-003-1 Standard.

  10. Multi-region relaxed magnetohydrodynamics with flow

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, G. R., E-mail: graham.dennis@anu.edu.au; Dewar, R. L.; Hole, M. J. [Research School of Physics and Engineering, Australian National University, ACT 0200 (Australia); Hudson, S. R. [Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543 (United States)

    2014-04-15

    We present an extension of the multi-region relaxed magnetohydrodynamics (MRxMHD) equilibrium model that includes plasma flow. This new model is a generalization of Woltjer's model of relaxed magnetohydrodynamics equilibria with flow. We prove that as the number of plasma regions becomes infinite, our extension of MRxMHD reduces to ideal MHD with flow. We also prove that some solutions to MRxMHD with flow are not time-independent in the laboratory frame, and instead have 3D structure which rotates in the toroidal direction with fixed angular velocity. This capability gives MRxMHD potential application to describing rotating 3D MHD structures such as 'snakes' and long-lived modes.

  11. Dissipation and the relaxation to equilibrium

    International Nuclear Information System (INIS)

    Evans, Denis J; Williams, Stephen R; Searles, Debra J

    2009-01-01

    Using the recently derived dissipation theorem and a corollary of the transient fluctuation theorem (TFT), namely the second-law inequality, we derive the unique time independent, equilibrium phase space distribution function for an ergodic Hamiltonian system in contact with a remote heat bath. We prove under very general conditions that any deviation from this equilibrium distribution breaks the time independence of the distribution. Provided temporal correlations decay, we show that any nonequilibrium distribution that is an even function of the momenta eventually relaxes (not necessarily monotonically) to the equilibrium distribution. Finally we prove that the negative logarithm of the microscopic partition function is equal to the thermodynamic Helmholtz free energy divided by the thermodynamic temperature and Boltzmann's constant. Our results complement and extend the findings of modern ergodic theory and show the importance of dissipation in the process of relaxation towards equilibrium

  12. Active nematic gels as active relaxing solids

    Science.gov (United States)

    Turzi, Stefano S.

    2017-11-01

    I propose a continuum theory for active nematic gels, defined as fluids or suspensions of orientable rodlike objects endowed with active dynamics, that is based on symmetry arguments and compatibility with thermodynamics. The starting point is our recent theory that models (passive) nematic liquid crystals as relaxing nematic elastomers. The interplay between viscoelastic response and active dynamics of the microscopic constituents is naturally taken into account. By contrast with standard theories, activity is not introduced as an additional term of the stress tensor, but it is added as an external remodeling force that competes with the passive relaxation dynamics and drags the system out of equilibrium. In a simple one-dimensional channel geometry, we show that the interaction between nonuniform nematic order and activity results in either a spontaneous flow of particles or a self-organization into subchannels flowing in opposite directions.

  13. Relaxation in the XX quantum chain

    International Nuclear Information System (INIS)

    Platini, Thierry; Karevski, Dragi

    2007-01-01

    We present the results obtained on the magnetization relaxation properties of an XX quantum chain in a transverse magnetic field. We first consider an initial thermal kink-like state where half of the chain is initially thermalized at a very high temperature T b while the remaining half, called the system, is put at a lower temperature T s . From this initial state, we derive analytically the Green function associated with the dynamical behaviour of the transverse magnetization. Depending on the strength of the magnetic field and on the temperature of the system, different regimes are obtained for the magnetic relaxation. In particular, with an initial droplet-like state, that is a cold subsystem of the finite size in contact at both ends with an infinite temperature environment, we derive analytically the behaviour of the time-dependent system magnetization

  14. Stress relaxation of thermally bowed fuel pins

    International Nuclear Information System (INIS)

    Crossland, I.G.; Speight, M.V.

    1983-01-01

    The presence of cross-pin temperature gradients in nuclear reactor fuel pins produces differential thermal expansion which, in turn, causes the fuel pin to bow elastically. If the pin is restrained in any way, such thermal bowing causes the pin to be stressed. At high temperatures these stresses can relax by creep and it is shown here that this causes the pin to suffer an additional permanent deflection, so that when the cross-pin temperature difference is removed the pin remains bowed. By representing the cylindrical pin by an equivalent I-beam, the present work examines this effect when it takes place by secondary creep. Two restraint systems are considered, and it is demonstrated that the rate of relaxation depends mainly upon the creep equation, and hence the temperature, and also the magnitude of the initial stresses. (author)

  15. Creep and relaxation behavior of Inconel-617

    International Nuclear Information System (INIS)

    Osthoff, W.; Ennis, P.J.; Nickel, H.; Schuster, H.

    1984-01-01

    The static and dynamic creep behavior of Inconel alloy 617 has been determined in constant load creep tests, relaxation tests, and stress reduction tests in the temperature range 1023 to 1273 K. The results have been interpreted using the internal stress concept: The dependence of the internal stress on the applied stress and test temperature was determined. In a few experiments, the influence of cold deformation prior to the creep test on the magnitude of the internal stress was also investigated. It was found that the experimentally observed relaxation behavior could be more satisfactorily described using the Norton creep equation modified by incorporation of the internal stress than by the conventional Norton creep equation

  16. Effective temperature in relaxation of Coulomb glasses.

    Science.gov (United States)

    Somoza, A M; Ortuño, M; Caravaca, M; Pollak, M

    2008-08-01

    We study relaxation in two-dimensional Coulomb glasses up to macroscopic times. We use a kinetic Monte Carlo algorithm especially designed to escape efficiently from deep valleys around metastable states. We find that, during the relaxation process, the site occupancy follows a Fermi-Dirac distribution with an effective temperature much higher than the real temperature T. Long electron-hole excitations are characterized by T(eff), while short ones are thermalized at T. We argue that the density of states at the Fermi level is proportional to T(eff) and is a good thermometer to measure it. T(eff) decreases extremely slowly, roughly as the inverse of the logarithm of time, and it should affect hopping conductance in many experimental circumstances.

  17. Microplastic relaxations of single and polycrystalline molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Pichl, W.; Weiss, B. [Wien Univ. (Austria). Inst. fuer Materialphysik; Chen, D.L.

    1998-05-01

    The microplasticity of high-purity molybdenum single crystals and of Mo polycrystals of technical purity has been investigated by relaxation step tests in uniaxial compression. A new model for the evaluation of relaxation tests in the microplastic range of b.c.c metals is presented which takes into account the decrease of the mobile dislocation density due to exhaustion of non-screw dislocations. The model allows an independent determination of the activation volume and of the microstructure parameters controlling dislocation exhaustion. The results indicate that in the high-purity single crystals the deformation rate is controlled by interactions of non-screw dislocations with the grown-in network. In the polycrystals additional interactions with impurity atoms seem to occur. In the single crystals the activity and subsequent exhaustion of two different glide systems was observed, followed by a gradual onset of screw dislocation motion. (orig.) 26 refs.

  18. Modern problems of relaxation gas dynamics

    International Nuclear Information System (INIS)

    Losev, S.A.; Osipov, A.I.

    1985-01-01

    Some of the dynamical characteristics of relaxation processes are studied. Unfortunately, many dynamical characteristics of relaxation processes, necessary for the solution of important scientific and applied problems, are not known. These problems require further development of experimental methods of the study of nonequilibrium gas. It is known, that gas systems are shifted from the equilibrium by different methods: by acoustic and shock wav es, by means of gas expansion in nozzles and jets, by powerful radiations (laser, first of all), by electric discharges, in burning and combustion devices, etc. Non-equilibrium gas is produced in installations of continuum, impulse and periodic regime. Molecular beams, shock tubes (especially with nozzles), flow and jet installations, aerodynamical tubes, plasmatrons, vessels with a gas, influenced by the strong radiation, burners and combustion devices, where the study of non-euilibrium gas is helpful to solve the problems of the determination of kinetic equations and constants of physico-chemical kinetics

  19. Impulsive relaxation process in MHD driven reconnection

    International Nuclear Information System (INIS)

    Kitabata, H.; Hayashi, T.; Sato, T.

    1997-01-01

    Compressible magnetohydrodynamic (MHD) simulation is carried out in order to investigate energy relaxation process of the driven magnetic reconnection in an open finite system through a long time calculation. It is found that a very impulsive energy release occurs in an intermittent fashion through magnetic reconnection for a continuous magnetic flux injection on the boundary. We focus our attention on the detailed process in the impulsive phase, which is the reconnection rate is remarkably enhanced up. (author)

  20. Current relaxation time scales in toroidal plasmas

    International Nuclear Information System (INIS)

    Mikkelsen, D.R.

    1987-02-01

    An approximate normal mode analysis of plasma current diffusion in tokamaks is presented. The work is based on numerical solutions of the current diffusion equation in cylindrical geometry. Eigenvalues and eigenfunctions are shown for a broad range of plasma conductivity profile shapes. Three classes of solutions are considered which correspond to three types of tokamak operation. Convenient approximations to the three lowest eigenvalues in each class are presented and simple formulae for the current relaxation time scales are given

  1. On real statistics of relaxation in gases

    Science.gov (United States)

    Kuzovlev, Yu. E.

    2016-02-01

    By example of a particle interacting with ideal gas, it is shown that the statistics of collisions in statistical mechanics at any value of the gas rarefaction parameter qualitatively differ from that conjugated with Boltzmann's hypothetical molecular chaos and kinetic equation. In reality, the probability of collisions of the particle in itself is random. Because of that, the relaxation of particle velocity acquires a power-law asymptotic behavior. An estimate of its exponent is suggested on the basis of simple kinematic reasons.

  2. Relaxation and kinetics in scalar field theories

    International Nuclear Information System (INIS)

    Boyanovsky, D.; Lawrie, I.D.; Lee, D.

    1996-01-01

    A new approach to the dynamics of relaxation and kinetics of thermalization in a scalar field theory is presented that incorporates the relevant time scales through the resummation of hard thermal loops. An alternative derivation of the kinetic equations for the open-quote open-quote quasiparticle close-quote close-quote distribution functions is obtained that allows a clear understanding of the different open-quote open-quote coarse-graining close-quote close-quote approximations usually involved in a kinetic description. This method leads to a systematic perturbative expansion to obtain the kinetic equations including hard thermal loop resummation and to an improvement including renormalization, off-shell effects, and contributions that change chemical equilibrium on short time scales. As a by-product of these methods we establish the equivalence between the relaxation time scale in the linearized equation of motion of the quasiparticles and the thermalization time scale of the quasiparticle distribution function in the open-quote open-quote relaxation time approximation close-quote close-quote including hard thermal loop effects. Hard thermal loop resummation dramatically modifies the scattering rate for long wavelength modes as compared to the usual (semi)classical estimate. Relaxation and kinetics are studied both in the unbroken and broken symmetry phases of the theory. The broken symmetry phase also provides the setting to obtain the contribution to the kinetic equations from processes that involve decay of a heavy scalar into light scalar particles in the medium. copyright 1996 The American Physical Society

  3. Muon spin relaxation in random spin systems

    International Nuclear Information System (INIS)

    Toshimitsu Yamazaki

    1981-01-01

    The longitudinal relaxation function Gsub(z)(t) of the positive muon can reflect dynamical characters of local field in a unique way even when the correlation time is longer than the Larmor period of local field. This method has been applied to studies of spin dynamics in spin glass systems, revealing sharp but continuous temperature dependence of the correlation time. Its principle and applications are reviewed. (author)

  4. Structural relaxation and thermal conductivity coefficient of liquids

    International Nuclear Information System (INIS)

    Abdurasulov, A.

    1992-01-01

    Present article is devoted to structural relaxation and thermal conductivity coefficient of liquids. The thermoelastic properties of liquids were studied taking into account the contribution of translational and structural relaxation. The results of determination of dynamic coefficient of thermal conductivity of liquids taking into account the contribution of translational and structural relaxation are presented.

  5. The Efficacy of Relaxation Training in Treating Anxiety

    Science.gov (United States)

    Francesco, Pagnini; Mauro, Manzoni Gian; Gianluca, Castelnuovo; Enrico, Molinari

    2009-01-01

    This paper provides a review of scientific literature about relaxation training and its effects on anxiety. Research investigating progressive relaxation, meditation, applied relaxation and autogenic training were considered. All these methods proved to be effective in reducing anxiety in all kind of samples, affected or not by physical or…

  6. Increase of transient lower esophageal sphincter relaxation associated with cascade stomach

    Science.gov (United States)

    Kawada, Akiyo; Kusano, Motoyasu; Hosaka, Hiroko; Kuribayashi, Shiko; Shimoyama, Yasuyuki; Kawamura, Osamu; Akiyama, Junichi; Yamada, Masanobu; Akuzawa, Masako

    2017-01-01

    We previously reported that cascade stomach was associated with reflux symptoms and esophagitis. Delayed gastric emptying has been believed to initiate transient lower esophageal sphincter relaxation (TLESR). We hypothesized that cascade stomach may be associated with frequent TLESR with delayed gastric emptying. Eleven subjects with cascade stomach and 11 subjects without cascade stomach were enrolled. Postprandial gastroesophageal manometry and gastric emptying using a continuous 13C breath system were measured simultaneously after a liquid test meal. TLESR events were counted in early period (0–60 min), late period (60–120 min), and total monitoring period. Three parameters of gastric emptying were calculated: the half emptying time, lag time, and gastric emptying coefficient. The median frequency of TLESR events in the cascade stomach and non-cascade stomach groups was 6.0 (median), 4.6 (interquartile range) vs 5.0, 3.0 in the early period, 5.0, 3.2 vs 3.0, 1.8 in the late period, and 10.0, 6.2 vs 8.0, 5.0 in the total monitoring period. TLESR events were significantly more frequent in the cascade stomach group during the late and total monitoring periods. In contrast, gastric emptying parameters showed no significant differences between the two groups. We concluded that TLESR events were significantly more frequent in persons with cascade stomach without delayed gastric emptying. PMID:28584403

  7. Ideal relaxation of the Hopf fibration

    Science.gov (United States)

    Smiet, Christopher Berg; Candelaresi, Simon; Bouwmeester, Dirk

    2017-07-01

    Ideal magnetohydrodynamics relaxation is the topology-conserving reconfiguration of a magnetic field into a lower energy state where the net force is zero. This is achieved by modeling the plasma as perfectly conducting viscous fluid. It is an important tool for investigating plasma equilibria and is often used to study the magnetic configurations in fusion devices and astrophysical plasmas. We study the equilibrium reached by a localized magnetic field through the topology conserving relaxation of a magnetic field based on the Hopf fibration in which magnetic field lines are closed circles that are all linked with one another. Magnetic fields with this topology have recently been shown to occur in non-ideal numerical simulations. Our results show that any localized field can only attain equilibrium if there is a finite external pressure, and that for such a field a Taylor state is unattainable. We find an equilibrium plasma configuration that is characterized by a lowered pressure in a toroidal region, with field lines lying on surfaces of constant pressure. Therefore, the field is in a Grad-Shafranov equilibrium. Localized helical magnetic fields are found when plasma is ejected from astrophysical bodies and subsequently relaxes against the background plasma, as well as on earth in plasmoids generated by, e.g., a Marshall gun. This work shows under which conditions an equilibrium can be reached and identifies a toroidal depression as the characteristic feature of such a configuration.

  8. Tension and relaxation in the individual.

    Science.gov (United States)

    Newbury, C R

    1979-06-01

    Increasing materialism in society is resulting in more wide spread nervous tension in all age groups. While some degree of nervous tension is necessary in everyday living, its adverse effects require that we must learn to bring it under control. Total tension is shown to have two components: a controllable element arising from factors in the environment and the inbuilt uncontrollable residue which is basic in the individual temperament. The effects of excessive or uncontrolled stress can be classified as 1) emotional reactions such as neurotic behaviour (anxiety hypochondria, hysteria, phobia, depression obsessions and compulsions) or psychotic behaviour and 2) psychosomatic reactions (nervous asthma, headache, insomnia, heart attack). Nervous energy can be wastefully expended by such factors as loss of temper, wrong attitudes to work, job frustration and marital strains. Relaxation is the only positive way to control undesirable nervous tension and its techniques require to be learned. A number of techniques (progressive relaxation, differential relaxation, hypnosis, the use of biofeedback, Yoga and Transcendental Meditation) are described and their application to dental practice is discussed.

  9. Characteristics of patients with internal diseases who use relaxation techniques as a coping strategy.

    Science.gov (United States)

    Cramer, Holger; Lauche, Romy; Langhorst, Jost; Dobos, Gustav; Paul, Anna

    2013-10-01

    To assess sociodemographic, clinical, and psychological characteristics of patients with internal diseases who use relaxation techniques as a coping strategy. Cross-sectional analysis among patients with internal diseases. Department of Internal and Integrative Medicine at an academic teaching hospital in Germany. Prior use of relaxation techniques (e.g. meditation, autogenic training), perceived benefit, and perceived harm. Potential predictors of relaxation techniques use (sociodemographic characteristics, health behavior, internal medicine diagnosis, general health status, mental health, satisfaction, and health locus of control) were tested using multiple logistic regression analysis. Of 2486 participants, 1075 (43.2%) reported to have used relaxation techniques, 648 (60.3%) reported benefits, and 11 (1.0%) reported harms. Use of relaxation techniques was independently associated with female gender (Odds ratio [OR]=1.43; 95% confidence interval [CI]=1.08-1.89), higher education (OR=1.32; 95%CI=1.03-1.71), fibromyalgia (OR=1.78; 95%CI=1.22-2.61), and internal health locus of control (OR=1.27; 95%CI=1.01-1.60). Use of relaxation techniques was negatively associated with age below 30 (OR=0.32; 95%CI=0.20-0.52) or above 64 (OR=0.65; 95%CI=0.49-0.88), full-time employment (OR=0.75; 95%CI=0.57-0.98), current smoking (OR=0.72; 95%CI=0.54-0.95), osteoarthritis (OR=0.51; 95%CI=0.34-0.77), rheumatic arthritis (OR=0.59; 95%CI=0.37-0.93), good to excellent health status (OR=0.70; 95%CI=0.52-0.96), and high life satisfaction (OR=0.78; 95%CI=0.62-0.98). In a German sample of patients with internal diseases, relaxation techniques were used as a coping strategy by about 43%. Users were more likely to be middle-aged, female, well-educated, diagnosed with fibromyalgia, not smoking, not full-time employed, and not to have a good health status or high life satisfaction. A high internal health locus of control predicted relaxation techniques use. Considering health locus of control

  10. ac Conductivity analysis and dielectric relaxation behaviour of NaNO3-Al2O3 composites

    International Nuclear Information System (INIS)

    Anantha, P.S.; Hariharan, K.

    2005-01-01

    The electrical conductivity of NaNO 3 -xAl 2 O 3 composites has been studied over the wide range of temperature and frequency by means of impedance spectroscopy. The real part of the frequency dependent conductivity exhibits a simple power law feature and the dimensionless frequency exponent n has been determined. The conductivity spectra show scaling behaviour when the conductivity spectra are scaled by σ dc T, where T is temperature in Kelvin. The real part of dielectric permittivity shows saturation at higher frequencies and a strong dispersion at lower frequencies. The imaginary part of permittivity varies inversely with frequency, due to the presence of dc conductivity. The frequency dependent plots of M' and Z' show that the conductivity relaxation is non-Debye in nature. The Kohlrausch-Williams-Watts stretched exponential function was used to describe the modulus spectra and the stretching exponent β is found to be temperature independent. The conductivity relaxation time has been estimated from the modulus spectra. The activation energy responsible for relaxation has been evaluated and it was found to be almost same as that of dc conductivity

  11. Frequency spirals

    International Nuclear Information System (INIS)

    Ottino-Löffler, Bertrand; Strogatz, Steven H.

    2016-01-01

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  12. Frequency spirals

    Energy Technology Data Exchange (ETDEWEB)

    Ottino-Löffler, Bertrand; Strogatz, Steven H., E-mail: strogatz@cornell.edu [Center for Applied Mathematics, Cornell University, Ithaca, New York 14853 (United States)

    2016-09-15

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  13. Effects of different "relaxing" music styles on the autonomic nervous system.

    Science.gov (United States)

    Perez-Lloret, Santiago; Diez, Joaquín; Domé, María Natalia; Delvenne, Andrea Alvarez; Braidot, Nestor; Cardinali, Daniel P; Vigo, Daniel Eduardo

    2014-01-01

    The objective of this study was to assess the effects on heart rate variability (HRV) of exposure to different styles of "relaxing" music. Autonomic responses to musical stimuli were correlated with subjective preferences regarding the relaxing properties of each music style. Linear and nonlinear HRV analysis was conducted in 25 healthy subjects exposed to silence or to classical, new age or romantic melodies in a random fashion. At the end of the study, subjects were asked to choose the melody that they would use to relax. The low-to-high-frequency ratio was significantly higher when subjects were exposed to "new age" music when compared with silence (3.4 ± 0.3 vs. 2.6 ± 0.3, respectively, P classical" or "romantic" melodies (2.1 ± 0.4 and 2.2 ± 0.3). These results were related to a reduction in the high frequency component with "new age" compared to silence (17.4 ± 1.9 vs. 23.1 ± 1.1, respectively P music induced a shift in HRV from higher to lower frequencies, independently on the music preference of the listener.

  14. Relaxation dynamics and thermophysical properties of vegetable oils using time-domain reflectometry.

    Science.gov (United States)

    Sonkamble, Anil A; Sonsale, Rahul P; Kanshette, Mahesh S; Kabara, Komal B; Wananje, Kunal H; Kumbharkhane, Ashok C; Sarode, Arvind V

    2017-04-01

    Dielectric relaxation studies of vegetable oils are important for insights into their hydrogen bonding and intermolecular dynamics. The dielectric relaxation and thermo physical properties of triglycerides present in some vegetable oils have been measured over the frequency range of 10 MHz to 7 GHz in the temperature region 25 to 10 °C using a time-domain reflectometry approach. The frequency and temperature dependence of dielectric constants and dielectric loss factors were determined for coconut, peanut, soya bean, sunflower, palm, and olive oils. The dielectric permittivity spectra for each of the studied vegetable oils are explained using the Debye model with their complex dielectric permittivity analyzed using the Havriliak-Negami equation. The dielectric parameters static permittivity (ε 0 ), high-frequency limiting static permittivity (ε ∞ ), average relaxation time (τ 0 ), and thermodynamic parameters such as free energy (∆F τ ), enthalpy (∆H τ ), and entropy of activation (∆S τ ) were also measured. Calculation and analysis of these thermodynamic parameters agrees with the determined dielectric parameters, giving insights into the temperature dependence of the molecular dynamics of these systems.

  15. Determining the structural relaxation times deep in the glassy state of the pharmaceutical Telmisartan

    Energy Technology Data Exchange (ETDEWEB)

    Adrjanowicz, K; Paluch, M [Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Ngai, K L [Naval Research Laboratory, Washington, DC 20375-5320 (United States)

    2010-03-31

    By using the dielectric relaxation method proposed recently by Casalini and Roland (2009 Phys. Rev. Lett. 102 035701), we were able to determine the structural alpha-relaxation times deep in the glassy state of the pharmaceutical, Telmisartan. Normally, deep in the glassy state tau{sub a}lpha is so long that it cannot be measured but tau{sub b}eta, which is usually much shorter, can be directly determined. The method basically takes advantage of the connection between the alpha-relaxation and the secondary beta-relaxation of the Johari-Goldstein kind, including a relation between their relaxation times tau{sub a}lpha and tau{sub b}eta, respectively. Thus, tau{sub a}lpha of Telmisartan were determined by monitoring the change of the dielectric beta-loss, epsilon'', with physical aging time at temperatures well below the vitrification temperature. The values of tau{sub a}lpha were compared with those expected by the coupling model (CM). Unequivocal comparison cannot be made in the case of Telmisartan because its beta-loss peak is extremely broad, and the CM predicts only an order of magnitude agreement between the primitive relaxation frequency and the beta-peak frequency. We also made an attempt to analyze all isothermal and aging susceptibility data after transformation into the electric modulus representation. The tau{sub a}lpha found in the glass state by using the method of Casalini and Roland in the modulus representation are similar to those obtained in the susceptibility representation. However, it is remarkable that the stretching parameter beta{sub KWWM} = 0.51 in the electric modulus representation gives more precise fits to the aging data than in the susceptibility representation with beta{sub KWW} = 0.61. Our results suggest that the electric modulus representation may be useful as an alternative to analyze aging data, especially in the case of highly polar glassformers having a large ratio of low frequency and high frequency dielectric

  16. A wrinkling-based method for investigating glassy polymer film relaxation as a function of film thickness and temperature.

    Science.gov (United States)

    Chung, Jun Young; Douglas, Jack F; Stafford, Christopher M

    2017-10-21

    We investigate the relaxation dynamics of thin polymer films at temperatures below the bulk glass transition T g by first compressing polystyrene films supported on a polydimethylsiloxane substrate to create wrinkling patterns and then observing the slow relaxation of the wrinkled films back to their final equilibrium flat state by small angle light scattering. As with recent relaxation measurements on thin glassy films reported by Fakhraai and co-workers, we find the relaxation time of our wrinkled films to be strongly dependent on film thickness below an onset thickness on the order of 100 nm. By varying the temperature between room temperature and T g (≈100 °C), we find that the relaxation time follows an Arrhenius-type temperature dependence to a good approximation at all film thicknesses investigated, where both the activation energy and the relaxation time pre-factor depend appreciably on film thickness. The wrinkling relaxation curves tend to cross at a common temperature somewhat below T g , indicating an entropy-enthalpy compensation relation between the activation free energy parameters. This compensation effect has also been observed recently in simulated supported polymer films in the high temperature Arrhenius relaxation regime rather than the glassy state. In addition, we find that the film stress relaxation function, as well as the height of the wrinkle ridges, follows a stretched exponential time dependence and the short-time effective Young's modulus derived from our modeling decreases sigmoidally with increasing temperature-both characteristic features of glassy materials. The relatively facile nature of the wrinkling-based measurements in comparison to other film relaxation measurements makes our method attractive for practical materials development, as well as fundamental studies of glass formation.

  17. Picosecond intersubband hole relaxation in p-type quantum wells

    International Nuclear Information System (INIS)

    Xu, Z.; Fauchet, P.M.; Rella, C.W.; Schwettman, H.A.

    1995-01-01

    We report the first direct measurement of the relaxation time of holes in p-type quantum wells using tunable, subpicosecond mid-infrared laser pulses in a pump-probe arrangement. The QW layers consisted of 50 In 0.5 Ga 0.5 As/Al 0.5 Ga 0.5 As periods. The In 0.5 Ga 0.5 As well was 4 nm wide and the Al 0.5 Ga 0.5 As barrier was 8 nm wide. The dopant concentration was 10 19 CM -3 which corresponds to a sheet density of 1.2 x 10 13 CM -2 . The room temperature IR spectrum showed a 50 meV wide absorption peak at 5.25 μm (220 meV). This energy agrees with the calculated n=1 heavy hole to n=1 light hole transition energy of 240 meV (150 meV for strain and 90 meV for confinement). The large absorption width results from hole-hole scattering and the difference in dispersion relations between the two subbands. The equal-wavelength pump-probe transmission measurements were performed using the Stanford free electron laser (FEL). The FEL pulses were tuned between 4 and 6 μ m and their duration was less than 1 ps. The measurements were performed as a function of temperature, pump wavelength and intensity (from 0.3 to 10 GW/cm 2 ). In all our experiments, we find an increase of transmission (decrease of absorption or bleaching) following photopumping, which recovers as a single exponential with a time constant (relaxation time) of the order of 1 picosecond. The maximum change in transmission is linear with pump 2 intensity below 1 GW/cm 2 and saturates to ∼3% with a saturation intensity I sat of 3 GW/cm 2 . As the saturation regime is entered, the relaxation time increases from 0.8 ps to 1.8 ps. This relaxation time depends on the temperature T: it increases from 0.8 ps to 1.3 ps as T decreases from 300 K to 77 K. Finally, when we tune the laser through the absorption band, the magnitude of the signal changes but its temporal behavior does not change, within the accuracy of the measurements

  18. Collective dynamic dipole moment and orientation fluctuations, cooperative hydrogen bond relaxations, and their connections to dielectric relaxation in ionic acetamide deep eutectics: Microscopic insight from simulations

    Energy Technology Data Exchange (ETDEWEB)

    Das, Suman [Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India); Biswas, Ranjit, E-mail: ranjit@bose.res.in, E-mail: biswaroop.mukherjee@gmail.com [Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India); Thematic Unit for Excellence – Computational Materials Science, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India); Mukherjee, Biswaroop, E-mail: ranjit@bose.res.in, E-mail: biswaroop.mukherjee@gmail.com [Thematic Unit for Excellence – Computational Materials Science, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India)

    2016-08-28

    The paper reports a detailed simulation study on collective reorientational relaxation, cooperative hydrogen bond (H-bond) fluctuations, and their connections to dielectric relaxation (DR) in deep eutectic solvents made of acetamide and three uni-univalent electrolytes, lithium nitrate (LiNO{sub 3}), lithium bromide (LiBr), and lithium perchlorate (LiClO{sub 4}). Because cooperative H-bond fluctuations and ion migration complicate the straightforward interpretation of measured DR timescales in terms of molecular dipolar rotations for these conducting media which support extensive intra- and inter-species H-bonding, one needs to separate out the individual components from the overall relaxation for examining the microscopic origin of various timescales. The present study does so and finds that reorientation of ion-complexed acetamide molecules generates relaxation timescales that are in sub-nanosecond to nanosecond range. This explains in molecular terms the nanosecond timescales reported by recent giga-Hertz DR measurements. Interestingly, the simulated survival timescale for the acetamide-Li{sup +} complex has been found to be a few tens of nanosecond, suggesting such a cation-complexed species may be responsible for a similar timescale reported by mega-Hertz DR measurements of acetamide/potassium thiocyanate deep eutectics near room temperature. The issue of collective versus single particle relaxation is discussed, and jump waiting time distributions are determined. Dependence on anion-identity in each of the cases has been examined. In short, the present study demonstrates that assumption of nano-sized domain formation is not required for explaining the DR detected nanosecond and longer timescales in these media.

  19. Spin manipulation and relaxation in spin-orbit qubits

    Science.gov (United States)

    Borhani, Massoud; Hu, Xuedong

    2012-03-01

    We derive a generalized form of the electric dipole spin resonance (EDSR) Hamiltonian in the presence of the spin-orbit interaction for single spins in an elliptic quantum dot (QD) subject to an arbitrary (in both direction and magnitude) applied magnetic field. We predict a nonlinear behavior of the Rabi frequency as a function of the magnetic field for sufficiently large Zeeman energies, and present a microscopic expression for the anisotropic electron g tensor. Similarly, an EDSR Hamiltonian is devised for two spins confined in a double quantum dot (DQD), where coherent Rabi oscillations between the singlet and triplet states are induced by jittering the inter-dot distance at the resonance frequency. Finally, we calculate two-electron-spin relaxation rates due to phonon emission, for both in-plane and perpendicular magnetic fields. Our results have immediate applications to current EDSR experiments on nanowire QDs, g-factor optimization of confined carriers, and spin decay measurements in DQD spin-orbit qubits.

  20. Charge carrier relaxation model in disordered organic semiconductors

    International Nuclear Information System (INIS)

    Lu, Nianduan; Li, Ling; Sun, Pengxiao; Liu, Ming

    2013-01-01

    The relaxation phenomena of charge carrier in disordered organic semiconductors have been demonstrated and investigated theoretically. An analytical model describing the charge carrier relaxation is proposed based on the pure hopping transport theory. The relation between the material disorder, electric field and temperature and the relaxation phenomena has been discussed in detail, respectively. The calculated results reveal that the increase of electric field and temperature can promote the relaxation effect in disordered organic semiconductors, while the increase of material disorder will weaken the relaxation. The proposed model can explain well the stretched-exponential law by adopting the appropriate parameters. The calculation shows a good agreement with the experimental data for organic semiconductors