WorldWideScience

Sample records for macroscopic mechanical motion

  1. Solvable Quantum Macroscopic Motions and Decoherence Mechanisms in Quantum Mechanics on Nonstandard Space

    Science.gov (United States)

    Kobayashi, Tsunehiro

    1996-01-01

    Quantum macroscopic motions are investigated in the scheme consisting of N-number of harmonic oscillators in terms of ultra-power representations of nonstandard analysis. Decoherence is derived from the large internal degrees of freedom of macroscopic matters.

  2. Conversion of light into macroscopic helical motion

    Science.gov (United States)

    Iamsaard, Supitchaya; Aßhoff, Sarah J.; Matt, Benjamin; Kudernac, Tibor; Cornelissen, Jeroen J. L. M.; Fletcher, Stephen P.; Katsonis, Nathalie

    2014-03-01

    A key goal of nanotechnology is the development of artificial machines capable of converting molecular movement into macroscopic work. Although conversion of light into shape changes has been reported and compared to artificial muscles, real applications require work against an external load. Here, we describe the design, synthesis and operation of spring-like materials capable of converting light energy into mechanical work at the macroscopic scale. These versatile materials consist of molecular switches embedded in liquid-crystalline polymer springs. In these springs, molecular movement is converted and amplified into controlled and reversible twisting motions. The springs display complex motion, which includes winding, unwinding and helix inversion, as dictated by their initial shape. Importantly, they can produce work by moving a macroscopic object and mimicking mechanical movements, such as those used by plant tendrils to help the plant access sunlight. These functional materials have potential applications in micromechanical systems, soft robotics and artificial muscles.

  3. On quantum mechanics for macroscopic systems

    International Nuclear Information System (INIS)

    Primas, H.

    1992-01-01

    The parable of Schroedinger's cat may lead to several up-to date questions: how to treat open systems in quantum theory, how to treat thermodynamically irreversible processes in the quantum mechanics framework, how to explain, following the quantum theory, the existence, phenomenologically evident, of classical observables, what implies the predicted existence by the quantum theory of non localized macroscopic material object ?

  4. Macroscopic quantum mechanics: theory and experimental concepts of optomechanics

    International Nuclear Information System (INIS)

    Chen Yanbei

    2013-01-01

    Rapid experimental progress has recently allowed the use of light to prepare macroscopic mechanical objects into nearly pure quantum states. This research field of quantum optomechanics opens new doors towards testing quantum mechanics, and possibly other laws of physics, in new regimes. In the first part of this article, I will review a set of techniques of quantum measurement theory that are often used to analyse quantum optomechanical systems. Some of these techniques were originally designed to analyse how a classical driving force passes through a quantum system, and can eventually be detected with an optimal signal-to-noise ratio—while others focus more on the quantum-state evolution of a mechanical object under continuous monitoring. In the second part of this article, I will review a set of experimental concepts that will demonstrate quantum mechanical behaviour of macroscopic objects—quantum entanglement, quantum teleportation and the quantum Zeno effect. Taking the interplay between gravity and quantum mechanics as an example, I will review a set of speculations on how quantum mechanics can be modified for macroscopic objects, and how these speculations—and their generalizations—might be tested by optomechanics. (invited review)

  5. Voltage Sensing in Membranes: From Macroscopic Currents to Molecular Motions.

    Science.gov (United States)

    Freites, J Alfredo; Tobias, Douglas J

    2015-06-01

    Voltage-sensing domains (VSDs) are integral membrane protein units that sense changes in membrane electric potential, and through the resulting conformational changes, regulate a specific function. VSDs confer voltage-sensitivity to a large superfamily of membrane proteins that includes voltage-gated Na[Formula: see text], K[Formula: see text], Ca[Formula: see text] ,and H[Formula: see text] selective channels, hyperpolarization-activated cyclic nucleotide-gated channels, and voltage-sensing phosphatases. VSDs consist of four transmembrane segments (termed S1 through S4). Their most salient structural feature is the highly conserved positions for charged residues in their sequences. S4 exhibits at least three conserved triplet repeats composed of one basic residue (mostly arginine) followed by two hydrophobic residues. These S4 basic side chains participate in a state-dependent internal salt-bridge network with at least four acidic residues in S1-S3. The signature of voltage-dependent activation in electrophysiology experiments is a transient current (termed gating or sensing current) upon a change in applied membrane potential as the basic side chains in S4 move across the membrane electric field. Thus, the unique structural features of the VSD architecture allow for competing requirements: maintaining a series of stable transmembrane conformations, while allowing charge motion, as briefly reviewed here.

  6. Collective motion of macroscopic spheres floating on capillary ripples: Dynamic heterogeneity and dynamic criticality

    NARCIS (Netherlands)

    Sanli, Ceyda; Saitoh, K.; Luding, Stefan; van der Meer, Roger M.

    2014-01-01

    When a densely packed monolayer of macroscopic spheres floats on chaotic capillary Faraday waves, a coexistence of large scale convective motion and caging dynamics typical for glassy systems is observed. We subtract the convective mean flow using a coarse graining (homogenization) method and reveal

  7. Analysis of macroscopic and microscopic rotating motions in rotating jets: A direct numerical simulation

    Directory of Open Access Journals (Sweden)

    Xingtuan Yang

    2015-05-01

    Full Text Available A direct numerical simulation study of the characteristics of macroscopic and microscopic rotating motions in swirling jets confined in a rectangular flow domain is carried out. The different structures of vortex cores for different swirl levels are illustrated. It is found that the vortex cores of low swirl flows are of regular cylindrical-helix patterns, whereas those of the high swirl flows are characterized by the formation of the bubble-type vortex breakdown followed by the radiant processing vortex cores. The results of mean velocity fields show the general procedures of vortex origination. Moreover, the effects of macroscopic and microscopic rotating motions with respect to the mean and fluctuation fields of the swirling flows are evaluated. The microscopic rotating effects, especially the effects with respect to the turbulent fluctuation motion, are increasingly intermittent with the increase in the swirl levels. In contrast, the maximum value of the probability density functions with respect to the macroscopic rotating effects of the fluctuation motion occurs at moderate swirl levels since the macroscopic rotating effects are attenuated by the formation of the bubble vortex breakdown with a region of stagnant fluids at supercritical swirl levels.

  8. Programmable motion of DNA origami mechanisms.

    Science.gov (United States)

    Marras, Alexander E; Zhou, Lifeng; Su, Hai-Jun; Castro, Carlos E

    2015-01-20

    DNA origami enables the precise fabrication of nanoscale geometries. We demonstrate an approach to engineer complex and reversible motion of nanoscale DNA origami machine elements. We first design, fabricate, and characterize the mechanical behavior of flexible DNA origami rotational and linear joints that integrate stiff double-stranded DNA components and flexible single-stranded DNA components to constrain motion along a single degree of freedom and demonstrate the ability to tune the flexibility and range of motion. Multiple joints with simple 1D motion were then integrated into higher order mechanisms. One mechanism is a crank-slider that couples rotational and linear motion, and the other is a Bennett linkage that moves between a compacted bundle and an expanded frame configuration with a constrained 3D motion path. Finally, we demonstrate distributed actuation of the linkage using DNA input strands to achieve reversible conformational changes of the entire structure on ∼ minute timescales. Our results demonstrate programmable motion of 2D and 3D DNA origami mechanisms constructed following a macroscopic machine design approach.

  9. Programmable motion of DNA origami mechanisms

    Science.gov (United States)

    Marras, Alexander E.; Zhou, Lifeng; Su, Hai-Jun; Castro, Carlos E.

    2015-01-01

    DNA origami enables the precise fabrication of nanoscale geometries. We demonstrate an approach to engineer complex and reversible motion of nanoscale DNA origami machine elements. We first design, fabricate, and characterize the mechanical behavior of flexible DNA origami rotational and linear joints that integrate stiff double-stranded DNA components and flexible single-stranded DNA components to constrain motion along a single degree of freedom and demonstrate the ability to tune the flexibility and range of motion. Multiple joints with simple 1D motion were then integrated into higher order mechanisms. One mechanism is a crank–slider that couples rotational and linear motion, and the other is a Bennett linkage that moves between a compacted bundle and an expanded frame configuration with a constrained 3D motion path. Finally, we demonstrate distributed actuation of the linkage using DNA input strands to achieve reversible conformational changes of the entire structure on ∼minute timescales. Our results demonstrate programmable motion of 2D and 3D DNA origami mechanisms constructed following a macroscopic machine design approach. PMID:25561550

  10. Nonisothermal Brownian motion: Thermophoresis as the macroscopic manifestation of thermally biased molecular motion.

    Science.gov (United States)

    Brenner, Howard

    2005-12-01

    A quiescent single-component gravity-free gas subject to a small steady uniform temperature gradient T, despite being at rest, is shown to experience a drift velocity UD=-D* gradient ln T, where D* is the gas's nonisothermal self-diffusion coefficient. D* is identified as being the gas's thermometric diffusivity alpha. The latter differs from the gas's isothermal isotopic self-diffusion coefficient D, albeit only slightly. Two independent derivations are given of this drift velocity formula, one kinematical and the other dynamical, both derivations being strictly macroscopic in nature. Within modest experimental and theoretical uncertainties, this virtual drift velocity UD=-alpha gradient ln T is shown to be constitutively and phenomenologically indistinguishable from the well-known experimental and theoretical formulas for the thermophoretic velocity U of a macroscopic (i.e., non-Brownian) non-heat-conducting particle moving under the influence of a uniform temperature gradient through an otherwise quiescent single-component rarefied gas continuum at small Knudsen numbers. Coupled with the size independence of the particle's thermophoretic velocity, the empirically observed equality, U=UD, leads naturally to the hypothesis that these two velocities, the former real and the latter virtual, are, in fact, simply manifestations of the same underlying molecular phenomenon, namely the gas's Brownian movement, albeit biased by the temperature gradient. This purely hydrodynamic continuum-mechanical equality is confirmed by theoretical calculations effected at the kinetic-molecular level on the basis of an existing solution of the Boltzmann equation for a quasi-Lorentzian gas, modulo small uncertainties pertaining to the choice of collision model. Explicitly, this asymptotically valid molecular model allows the virtual drift velocity UD of the light gas and the thermophoretic velocity U of the massive, effectively non-Brownian, particle, now regarded as the tracer particle

  11. Quantum mechanics versus macroscopic realism: Is the flux there when nobody looks

    International Nuclear Information System (INIS)

    Leggett, A.J.; Garg, A.

    1985-01-01

    It is shown that, in the contect of an idealized ''macroscopic quantum coherence'' experiment, the prediction of quantum mechanics are incompattible with the conjunction of two general assimptions which are designated ''macroscopic realism'' and ''noninvasive measurability at the macroscopiclevel.'' The conditions under which quantum mechanics can be tested against these assumptions in a realistic experiment are discussed

  12. Collective motion of macroscopic spheres floating on capillary ripples: dynamic heterogeneity and dynamic criticality.

    Science.gov (United States)

    Sanlı, Ceyda; Saitoh, Kuniyasu; Luding, Stefan; van der Meer, Devaraj

    2014-09-01

    When a densely packed monolayer of macroscopic spheres floats on chaotic capillary Faraday waves, a coexistence of large scale convective motion and caging dynamics typical for glassy systems is observed. We subtract the convective mean flow using a coarse graining (homogenization) method and reveal subdiffusion for the caging time scales followed by a diffusive regime at later times. We apply the methods developed to study dynamic heterogeneity and show that the typical time and length scales of the fluctuations due to rearrangements of observed particle groups significantly increase when the system approaches its largest experimentally accessible packing concentration. To connect the system to the dynamic criticality literature, we fit power laws to our results. The resultant critical exponents are consistent with those found in densely packed suspensions of colloids.

  13. Photoactuators for Direct Optical-to-Mechanical Energy Conversion: From Nanocomponent Assembly to Macroscopic Deformation.

    Science.gov (United States)

    Hu, Ying; Li, Zhe; Lan, Tian; Chen, Wei

    2016-12-01

    Photoactuators with integrated optical-to-mechanical energy conversion capacity have attracted growing research interest in the last few decades due to their unique features of remote control and their wide applications ranging from bionic robots, biomedical devices, and switches to motors. For the photoactuator design, the energy conversion route and structure assembly are two important parts, which directly affect the performance of the photoactuators. In particular, the architectural designs at the molecular, nano-, micro-, and macro- level, are found to play a significant role in accumulating molecular-scale strain/stress to macroscale strain/stress. Here, recent progress on photoactuators based on photochemical and photothermal effects is summarized, followed by a discussion of the important assembly strategies for the amplification of the photoresponsive components at nanoscale to macroscopic scale motions. The application advancement of current photoactuators is also presented. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Macroscopic objects in quantum mechanics: A combinatorial approach

    International Nuclear Information System (INIS)

    Pitowsky, Itamar

    2004-01-01

    Why do we not see large macroscopic objects in entangled states? There are two ways to approach this question. The first is dynamic. The coupling of a large object to its environment cause any entanglement to decrease considerably. The second approach, which is discussed in this paper, puts the stress on the difficulty of observing a large-scale entanglement. As the number of particles n grows we need an ever more precise knowledge of the state and an ever more carefully designed experiment, in order to recognize entanglement. To develop this point we consider a family of observables, called witnesses, which are designed to detect entanglement. A witness W distinguishes all the separable (unentangled) states from some entangled states. If we normalize the witness W to satisfy tr(Wρ)≤1 for all separable states ρ, then the efficiency of W depends on the size of its maximal eigenvalue in absolute value; that is, its operator norm parallel W parallel . It is known that there are witnesses on the space of n qubits for which parallel W parallel is exponential in n. However, we conjecture that for a large majority of n-qubit witnesses parallel W parallel ≤O(√(n log n)). Thus, in a nonideal measurement, which includes errors, the largest eigenvalue of a typical witness lies below the threshold of detection. We prove this conjecture for the family of extremal witnesses introduced by Werner and Wolf [Phys. Rev. A 64, 032112 (2001)

  15. The effect of interlayer adhesion on the mechanical behaviors of macroscopic graphene oxide papers.

    Science.gov (United States)

    Gao, Yun; Liu, Lu-Qi; Zu, Sheng-Zhen; Peng, Ke; Zhou, Ding; Han, Bao-Hang; Zhang, Zhong

    2011-03-22

    High mechanical performances of macroscopic graphene oxide (GO) papers are attracting great interest owing to their merits of lightweight and multiple functionalities. However, the loading role of individual nanosheets and its effect on the mechanical properties of the macroscopic GO papers are not yet well understood. Herein, we effectively tailored the interlayer adhesions of the GO papers by introducing small molecules, that is, glutaraldehyde (GA) and water molecules, into the gallery regions. With the help of in situ Raman spectroscopy, we compared the varied load-reinforcing roles of nanosheets, and further predicted the Young's moduli of the GO papers. Systematic mechanical tests have proven that the enhancement of the tensile modulus and strength of the GA-treated GO paper arose from the improved load-bearing capability of the nanosheets. On the basis of Raman and macroscopic mechanical tests, the influences of interlayer adhesions on the fracture mechanisms of the strained GO papers were inferred.

  16. Mechanical Behaviour of Materials Volume 1 Micro- and Macroscopic Constitutive Behaviour

    CERN Document Server

    François, Dominique; Zaoui, André

    2012-01-01

    Advances in technology are demanding ever-increasing mastery over the materials being used: the challenge is to gain a better understanding of their behaviour, and more particularly of the relations between their microstructure and their macroscopic properties.   This work, of which this is the first volume, aims to provide the means by which this challenge may be met. Starting from the mechanics of deformation, it develops the laws governing macroscopic behaviour – expressed as the constitutive equations – always taking account of the physical phenomena which underlie rheological behaviour. The most recent developments are presented, in particular those concerning heterogeneous materials such as metallic alloys, polymers and composites. Each chapter is devoted to one of the major classes of material behaviour.   As the subtitles indicate, Volume 1 deals with micro- and macroscopic constitutive behaviour and Volume 2 with damage and fracture mechanics. A third volume will be devoted to exercises and the...

  17. Influence of the Doppler effect on radiative transfer in a spherical plasma under macroscopic motion of substance

    Science.gov (United States)

    Kosarev, N. I.

    2018-03-01

    The non-LTE radiative transfer in spherical plasma containing resonantly absorbing light ions has been studied numerically under conditions of macroscopic motion of substance. Two types of macroscopic motion were simulated: radial expansion and compression (pulsation) of spherical plasma; rotation of plasma relative to an axis of symmetry. The calculations of absorption line profile of transmitted broadband radiation and the emission line profile were performed for the optically dense plasma of calcium ions on the resonance transition with wavelength 397 nm. Numerical results predict frequency shifts in the emission line profile to red wing of the spectrum for radial expansion of the plasma and to blue wing of the spectrum for the plasma compression at an average velocity of ions along the ray of sight equal to zero. The width of the emission line profile of a rotating plasma considerably exceeds the width of the profile of the static plasma, and the shift of the central frequency of resonance transition from the resonance frequency of the static plasma gives a linear velocity of ion motion along a given ray trajectory in units of thermal velocity. Knowledge of the linear radial velocity of ions can be useful for diagnostic purposes in determining the frequency and period of rotation of optically dense plasmas.

  18. Time-dependent mechanical behavior of human amnion: Macroscopic and microscopic characterization

    OpenAIRE

    2014-01-01

    © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Characterizing the mechanical response of the human amnion is essential to understand and to eventually prevent premature rupture of fetal membranes. In this study a large set of macroscopic and microscopic mechanical tests have been carried out on fresh unfixed amnion to gain insight into the time dependent material response and the underlying mechanisms. Creep and relaxation responses of amnion were characterized in...

  19. Faithful conversion of propagating quantum information to mechanical motion

    Science.gov (United States)

    Reed, A. P.; Mayer, K. H.; Teufel, J. D.; Burkhart, L. D.; Pfaff, W.; Reagor, M.; Sletten, L.; Ma, X.; Schoelkopf, R. J.; Knill, E.; Lehnert, K. W.

    2017-12-01

    The motion of micrometre-sized mechanical resonators can now be controlled and measured at the fundamental limits imposed by quantum mechanics. These resonators have been prepared in their motional ground state or in squeezed states, measured with quantum-limited precision, and even entangled with microwave fields. Such advances make it possible to process quantum information using the motion of a macroscopic object. In particular, recent experiments have combined mechanical resonators with superconducting quantum circuits to frequency-convert, store and amplify propagating microwave fields. But these systems have not been used to manipulate states that encode quantum bits (qubits), which are required for quantum communication and modular quantum computation. Here we demonstrate the conversion of propagating qubits encoded as superpositions of zero and one photons to the motion of a micromechanical resonator with a fidelity in excess of the classical bound. This ability is necessary for mechanical resonators to convert quantum information between the microwave and optical domains or to act as storage elements in a modular quantum information processor. Additionally, these results are an important step towards testing speculative notions that quantum theory may not be valid for sufficiently massive systems.

  20. Macroscopic and microscopic description of HE-HI collisions; classical equations of motion calculations

    International Nuclear Information System (INIS)

    Bodmer, A.R.

    1978-01-01

    The study of high energy heavy ion reactions includes the three principle a priori approaches used for central collisions, namely, hydrodynamics, cascade--Boltzman equation, and the classical equations of motion. While no clearly justified central or near central collisions are found, the classical equations of motion are used to illustrate some general features of these reactions. It is expected that the hot nuclear matter produced in such collisions is a dense, viscous, and thermally conductive fluid with important nonequilibrium and nonclassical features, rapidity, distribution, noncentral collisions, potential dependent effects for a given two-body scattering, and c.m. cross sections for a central collision with given parameters are among the properties considered. 12 references

  1. Tracking of macroscopic particle motions generated by a turbulent wind via digital image analysis

    Science.gov (United States)

    Ciccone, A. D.; Kawall, J. G.; Keffer, J. F.

    A novel technique utilizing the basic principles of two-dimensional signal analysis and artificial intelligence/computer vision to reconstruct the Lagrangian particle trajectories from flow visualization images of macroparticle motions in a turbulent boundary layer is presented. Since, in most cases, the entire trajectory of a particle could not be viewed in one photographic frame (the particles were moving at a high velocity over a small field of view), a stochastic model was developed to complete the trajectories and obtain statistical data on particle velocities. The associated programs were implemented on a Cray supercomputer to optimize computational costs and time.

  2. Electrically and mechanically induced macroscopic body couple, a newly recognized phenomenon of electromechanical interaction

    International Nuclear Information System (INIS)

    Chen, P.J.

    1986-01-01

    Microscopically, when the molecules of certain materials are under the influence of external stimuli such as mechanical and electrical forces, several processes can happen. In particular, the centers of charge of the positive and negative ions of a molecule may displace with respect to each other. This notion leads to the macroscopic concept of polarization which has been exploited in the classical studies of piezoelectric and ferroelectric materials. In addition, the ions of the molecule may also rotate angularly relative to one another. Here an entirely new macroscopic concept of body couple which differs from the classical concept is introduced. It is shown that the simplest representations of the proposed constitutive relations lead to an equation within the context of the classical bending theory of thin plates whose solution is in remarkable agreement with recent experimental results concerning the bending of thin virgin ferroelectric ceramic discs under the action of small d.c. voltages. These experimental results cannot be explained by the classical notion of polarization. Therefore, the concept of macroscopic body couple introduced here is a fundamental feature which must be taken into account in the considerations of electromechanical interactions

  3. Preparation of Liquid Crystal Networks for Macroscopic Oscillatory Motion Induced by Light.

    Science.gov (United States)

    Vantomme, Ghislaine; Gelebart, Anne Helene; Broer, Dirk J; Meijer, E W

    2017-09-20

    A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous light irradiation. The photo-excitation of dopants that can quickly dissipate light into heat, coupled with anisotropic thermal expansion and self-shadowing of the film, gives rise to the self-sustained deformation. The oscillations observed are influenced by the dimensions and the modulus of the film, and by the directionality and intensity of the light. The system developed offers applications in energy conversion and harvesting for soft-robotics and automated systems. The general method described here consists of creating free-standing liquid crystalline films and characterizing the mechanical and thermal effects observed. The molecular alignment is achieved using alignment layers (rubbed polyimide), commonly used in the display manufacturing industry. To obtain actuators with large deformation, the mesogens are aligned and polymerized in a splay/bend configuration, i.e., with the director of the liquid crystals (LCs) going gradually from planar to homeotropic through the film thickness. Upon irradiation, the mechanical and thermal oscillations obtained are monitored with a high-speed camera. The results are further quantified by image analysis using an image processing program.

  4. Quantum hologram of macroscopically entangled light via the mechanism of diffuse light storage

    International Nuclear Information System (INIS)

    Gerasimov, L V; Sokolov, I M; Kupriyanov, D V; Havey, M D

    2012-01-01

    In this paper, we consider a quantum memory scheme for light diffusely propagating through a spatially disordered atomic gas. A unique characteristic is enhanced trapping of the signal light pulse by quantum multiple scattering, which can be naturally integrated with the mechanism of stimulated Raman conversion into a long-lived spin coherence. Then, the quantum state of the light can be mapped onto the disordered atomic spin subsystem and can be stored in it for a relatively long time. The proposed memory scheme can be applicable for storage of the macroscopic analogue of the Ψ (−) Bell state and the prepared entangled atomic state performs its quantum hologram, which suggests the possibility of further quantum information processing. (paper)

  5. Ab Initio Modeling Of Friction Reducing Agents Shows Quantum Mechanical Interactions Can Have Macroscopic Manifestation.

    Science.gov (United States)

    Hernández Velázquez, J D; Barroso-Flores, J; Gama Goicochea, A

    2016-11-23

    Two of the most commonly encountered friction-reducing agents used in plastic sheet production are the amides known as erucamide and behenamide, which despite being almost identical chemically, lead to markedly different values of the friction coefficient. To understand the origin of this contrasting behavior, in this work we model brushes made of these two types of linear-chain molecules using quantum mechanical numerical simulations under the density functional theory at the B97D/6-31G(d,p) level of theory. Four chains of erucamide and behenamide were linked to a 2 × 10 zigzag graphene sheet and optimized both in vacuum and in continuous solvent using the SMD implicit solvation model. We find that erucamide chains tend to remain closer together through π-π stacking interactions arising from the double bonds located at C13-C14, a feature behenamide lacks, and thus a more spread configuration is obtained with the latter. It is argued that this arrangement of the erucamide chains is responsible for the lower friction coefficient of erucamide brushes, compared with behenamide brushes, which is a macroscopic consequence of cooperative quantum mechanical interactions. While only quantum level interactions are modeled here, we show that behenamide chains are more spread out in the brush than erucamide chains as a consequence of those interactions. The spread-out configuration allows more solvent particles to penetrate the brush, leading in turn to more friction, in agreement with macroscopic measurements and mesoscale simulations of the friction coefficient reported in the literature.

  6. Models for universal reduction of macroscopic quantum fluctuations

    International Nuclear Information System (INIS)

    Diosi, L.

    1988-10-01

    If quantum mechanics is universal, then macroscopic bodies would, in principle, possess macroscopic quantum fluctuations (MQF) in their positions, orientations, densities etc. Such MQF, however, are not observed in nature. The hypothesis is adopted that the absence of MQF is due to a certain universal mechanism. Gravitational measures were applied for reducing MQF of the mass density. This model leads to classical trajectories in the macroscopic limit of translational motion. For massive objects, unwanted macroscopic superpositions of quantum states will be destroyed within short times. (R.P.) 34 refs

  7. Hot deformation of polycrystalline uranium dioxide: from microscopic mechanisms to macroscopic behaviour

    International Nuclear Information System (INIS)

    Dherbey, Francine

    2000-01-01

    The improvement of nuclear fuels performances in PWR requires in particular an enhancement of creep ability of uranium dioxide in order to minimise rupture risks of the cladding material during interactions between pellets and cladding. The aim of this study is to investigate the link between the ceramic macroscopic thermo-mechanical behaviour and the changes in the fuel microstructure during deformation. Stoichiometric UO 2 pellets with various grains sizes from 9 pm to 36 μm have been deformed by compression at intermediate temperatures, i.e. near T M /2, and quenched under stress. The damage is characterised by the presence of cavities at low stresses and cracks at high stresses, both along grain boundaries parallel to the compression axis. Inside grains, dislocations organise themselves into cellular substructures in which sub-boundaries are made of dislocation hexagonal networks. In these conditions, uranium dioxide deformation is described by grain boundary sliding, which is the main origin of material damage, partially accommodated by dislocational creep inside grains. A steady-state creep model is proposed on a physical basis. It accounts for the almost similar contributions of two mechanisms which are grain boundaries sliding and intragranular creep, and takes into account the grain boundary roughness. In contrast with phenomenological descriptions used up to now, this picture leads to a unique creep law on the whole range of stresses explored here, from 10 MPa to 80 MPa. The creep rate controlling mechanism seems to be the migration of sub-boundaries. The deformation at constant strain rate is controlled by the same mechanisms as creep. (author) [fr

  8. Scale relativity theory and integrative systems biology: 2. Macroscopic quantum-type mechanics.

    Science.gov (United States)

    Nottale, Laurent; Auffray, Charles

    2008-05-01

    In these two companion papers, we provide an overview and a brief history of the multiple roots, current developments and recent advances of integrative systems biology and identify multiscale integration as its grand challenge. Then we introduce the fundamental principles and the successive steps that have been followed in the construction of the scale relativity theory, which aims at describing the effects of a non-differentiable and fractal (i.e., explicitly scale dependent) geometry of space-time. The first paper of this series was devoted, in this new framework, to the construction from first principles of scale laws of increasing complexity, and to the discussion of some tentative applications of these laws to biological systems. In this second review and perspective paper, we describe the effects induced by the internal fractal structures of trajectories on motion in standard space. Their main consequence is the transformation of classical dynamics into a generalized, quantum-like self-organized dynamics. A Schrödinger-type equation is derived as an integral of the geodesic equation in a fractal space. We then indicate how gauge fields can be constructed from a geometric re-interpretation of gauge transformations as scale transformations in fractal space-time. Finally, we introduce a new tentative development of the theory, in which quantum laws would hold also in scale space, introducing complexergy as a measure of organizational complexity. Initial possible applications of this extended framework to the processes of morphogenesis and the emergence of prokaryotic and eukaryotic cellular structures are discussed. Having founded elements of the evolutionary, developmental, biochemical and cellular theories on the first principles of scale relativity theory, we introduce proposals for the construction of an integrative theory of life and for the design and implementation of novel macroscopic quantum-type experiments and devices, and discuss their potential

  9. Nonlinear optomechanical measurement of mechanical motion

    DEFF Research Database (Denmark)

    Brawley, G.A.; Vanner, M R; Larsen, Peter Emil

    2016-01-01

    Precision measurement of nonlinear observables is an important goal in all facets of quantum optics. This allows measurement-based non-classical state preparation, which has been applied to great success in various physical systems, and provides a route for quantum information processing with oth......Precision measurement of nonlinear observables is an important goal in all facets of quantum optics. This allows measurement-based non-classical state preparation, which has been applied to great success in various physical systems, and provides a route for quantum information processing...... with otherwise linear interactions. In cavity optomechanics much progress has been made using linear interactions and measurement, but observation of nonlinear mechanical degrees-of-freedom remains outstanding. Here we report the observation of displacement-squared thermal motion of a micro-mechanical resonator...... by exploiting the intrinsic nonlinearity of the radiation-pressure interaction. Using this measurement we generate bimodal mechanical states of motion with separations and feature sizes well below 100 pm. Future improvements to this approach will allow the preparation of quantum superposition states, which can...

  10. Support motions for mechanical components during earthquakes

    International Nuclear Information System (INIS)

    Hadjian, A.H.

    1979-01-01

    The functioning of mechanical and other equipment during and after earthquakes may not only be necessary to avoid catastrophic consequences, such as in nuclear facilities, but also to guarantee the adequate functioning of emergency facilities (hospitals and fire stations, for example) that are necessary to cope with the aftermath of an earthquake. The state-of-the-art methods used for prescribing support motions to equipment in structures is reviewed from the elementary to the more complex. Also reviewed are the justifications for the uncoupling of the equipment from the structure for purposes of analysis, and the impacts that uncertainties in the total process may have on equipment design. (author)

  11. A mechanical mechanism for translocation of ring-shaped helicases on DNA and its demonstration in a macroscopic simulation system

    Science.gov (United States)

    Chou, Y. C.

    2018-04-01

    The asymmetry in the two-layered ring structure of helicases and the random thermal fluctuations of the helicase and DNA molecules are considered as the bases for the generation of the force required for translocation of the ring-shaped helicase on DNA. The helicase comprises a channel at its center with two unequal ends, through which strands of DNA can pass. The random collisions between the portion of the DNA strand in the central channel and the wall of the channel generate an impulsive force toward the small end. This impulsive force is the starting point for the helicase to translocate along the DNA with the small end in front. Such a physical mechanism may serve as a complementary for the chemomechanical mechanism of the translocation of helicase on DNA. When the helicase arrives at the junction of ssDNA and dsDNA (a fork), the collision between the helicase and the closest base pair may produce a sufficient impulsive force to break the weak hydrogen bond of the base pair. Thus, the helicase may advance and repeat the process of unwinding the dsDNA strand. This mechanism was tested in a macroscopic simulation system where the helicase was simulated using a truncated-cone structure and DNA was simulated with bead chains. Many features of translocation and unwinding such as translocation on ssDNA and dsDNA, unwinding of dsDNA, rewinding, strand switching, and Holliday junction resolution were reproduced.

  12. Testing quantum mechanics against macroscopic realism using the output of χ(2) nonlinearity

    International Nuclear Information System (INIS)

    Podoshvedov, Sergey A.; Kim, Jaewan

    2006-01-01

    We suggest an all-optical scheme to generate entangled superposition of a single photon with macroscopic entangled states for testing macroscopic realism. The scheme consists of source of single photons, a Mach-Zehnder interferometer in routes of which a system of coupled-down converters with type-I phase matching is inserted, and a beam splitter for the other auxiliary modes of the scheme. We use quantization of the pumping modes, depletion of the coherent states passing through the system, and interference effect in the pumping modes in the process of erasing which-path information of the single-photon on exit from the Mach-Zehnder interferometer. We show the macroscopic fields of the output superposition are distinguishable states. This scheme generates macroscopic entangled state that violates Bell's inequality. Moreover, the detailed analysis concerning change of amplitudes of entangled superposition by means of repeating this process many times is accomplished. We show our scheme works without photon number resolving detection and it is robust to detector inefficiency

  13. QUANTUM MECHANICS. Quantum squeezing of motion in a mechanical resonator.

    Science.gov (United States)

    Wollman, E E; Lei, C U; Weinstein, A J; Suh, J; Kronwald, A; Marquardt, F; Clerk, A A; Schwab, K C

    2015-08-28

    According to quantum mechanics, a harmonic oscillator can never be completely at rest. Even in the ground state, its position will always have fluctuations, called the zero-point motion. Although the zero-point fluctuations are unavoidable, they can be manipulated. Using microwave frequency radiation pressure, we have manipulated the thermal fluctuations of a micrometer-scale mechanical resonator to produce a stationary quadrature-squeezed state with a minimum variance of 0.80 times that of the ground state. We also performed phase-sensitive, back-action evading measurements of a thermal state squeezed to 1.09 times the zero-point level. Our results are relevant to the quantum engineering of states of matter at large length scales, the study of decoherence of large quantum systems, and for the realization of ultrasensitive sensing of force and motion. Copyright © 2015, American Association for the Advancement of Science.

  14. Facial motion engages predictive visual mechanisms.

    Directory of Open Access Journals (Sweden)

    Jordy Kaufman

    Full Text Available We employed a novel cuing paradigm to assess whether dynamically versus statically presented facial expressions differentially engaged predictive visual mechanisms. Participants were presented with a cueing stimulus that was either the static depiction of a low intensity expressed emotion; or a dynamic sequence evolving from a neutral expression to the low intensity expressed emotion. Following this cue and a backwards mask, participants were presented with a probe face that displayed either the same emotion (congruent or a different emotion (incongruent with respect to that displayed by the cue although expressed at a high intensity. The probe face had either the same or different identity from the cued face. The participants' task was to indicate whether or not the probe face showed the same emotion as the cue. Dynamic cues and same identity cues both led to a greater tendency towards congruent responding, although these factors did not interact. Facial motion also led to faster responding when the probe face was emotionally congruent to the cue. We interpret these results as indicating that dynamic facial displays preferentially invoke predictive visual mechanisms, and suggest that motoric simulation may provide an important basis for the generation of predictions in the visual system.

  15. Auditory motion-specific mechanisms in the primate brain.

    Directory of Open Access Journals (Sweden)

    Colline Poirier

    2017-05-01

    Full Text Available This work examined the mechanisms underlying auditory motion processing in the auditory cortex of awake monkeys using functional magnetic resonance imaging (fMRI. We tested to what extent auditory motion analysis can be explained by the linear combination of static spatial mechanisms, spectrotemporal processes, and their interaction. We found that the posterior auditory cortex, including A1 and the surrounding caudal belt and parabelt, is involved in auditory motion analysis. Static spatial and spectrotemporal processes were able to fully explain motion-induced activation in most parts of the auditory cortex, including A1, but not in circumscribed regions of the posterior belt and parabelt cortex. We show that in these regions motion-specific processes contribute to the activation, providing the first demonstration that auditory motion is not simply deduced from changes in static spatial location. These results demonstrate that parallel mechanisms for motion and static spatial analysis coexist within the auditory dorsal stream.

  16. A Mini Review on Nanocarbon-Based 1D Macroscopic Fibers:Assembly Strategies and Mechanical Properties

    Institute of Scientific and Technical Information of China (English)

    Liang Kou; Yingjun Liu; Cheng Zhang; Le Shao; Zhanyuan Tian; Zengshe Deng; Chao Gao

    2017-01-01

    Nanocarbon-based materials, such as carbon nanotubes(CNTs) and graphene have been attached much attention by scientific and industrial community. As two representative nanocarbon materials, one-dimensional CNTs and twodimensional graphene both possess remarkable mechanical properties. In the past years, a large amount of work have been done by using CNTs or graphene as building blocks for constructing novel, macroscopic, mechanically strong fibrous materials. In this review, we summarize the assembly approaches of CNT-based fibers and graphene-based fibers in chronological order, respectively. The mechanical performances of these fibrous materials are compared, and the critical influences on the mechanical properties are discussed. Personal perspectives on the fabrication methods of CNT-and graphene-based fibers are further presented.

  17. Remarks on the motion of macroscopic and microscopic spinning particles in relativity; Remarques sur le mouvement des particules a spin macroscopiques et microscopiques en relativite

    Energy Technology Data Exchange (ETDEWEB)

    Micoulaut, R [Commissariat a l' Energie Atomique, Limeil-Brevannes (France). Centre d' Etudes

    1968-07-01

    The Papapetrou equations of motion of a spinning particle do not allow the unequivocal determination of the world-line described by the particle. The motion should be completely determined in adding a supplementary condition. For macroscopic particles, characterized by the conditions of Corinaldesi-Papapetrou and Tulczyjew, moving in a Schwarzschild field we obtain additional term in the expression for the advance of perihelion. For microscopic particles we summarize the results obtained using the conditions of Weyssenhoff, Nakano, Hoenl-Papapetrou and Wessel. (author) [French] Les equations de Papapetrou decrivant le mouvement d'une particule a spin ne permettent pas de fixer de maniere univoque la ligne d'univers que parcourt la particule. Le mouvement sera completement determine en imposant une condition supplementaire arbitraire. Pour des particules macroscopiques, caracterisees par les conditions de Corinaldesi-Papapetrou et Tulczyjew, se deplacant dans un champ de Schwarzschild on obtient un terme supplementaire dans l'expression de l'avance du perihelie. Pour les particules microscopiques on rappellera rapidement les resultats obtenus en utilisant les conditions simples de Weyssenhoff, Nakano, Hoenl-Papapetrou et Wessel. (auteur)

  18. Hierarchical macroscopic fibrillar adhesives: in situ study of buckling and adhesion mechanisms on wavy substrates.

    Science.gov (United States)

    Bauer, Christina T; Kroner, Elmar; Fleck, Norman A; Arzt, Eduard

    2015-10-23

    Nature uses hierarchical fibrillar structures to mediate temporary adhesion to arbitrary substrates. Such structures provide high compliance such that the flat fibril tips can be better positioned with respect to asperities of a wavy rough substrate. We investigated the buckling and adhesion of hierarchically structured adhesives in contact with flat smooth, flat rough and wavy rough substrates. A macroscopic model for the structural adhesive was fabricated by molding polydimethylsiloxane into pillars of diameter in the range of 0.3-4.8 mm, with up to three different hierarchy levels. Both flat-ended and mushroom-shaped hierarchical samples buckled at preloads one quarter that of the single level structures. We explain this behavior by a change in the buckling mode; buckling leads to a loss of contact and diminishes adhesion. Our results indicate that hierarchical structures can have a strong influence on the degree of adhesion on both flat and wavy substrates. Strategies are discussed that achieve highly compliant substrates which adhere to rough substrates.

  19. PCB congener sorption to carbonaceous sediment components: Macroscopic comparison and characterization of sorption kinetics and mechanism

    International Nuclear Information System (INIS)

    Choi, Hyeok; Al-Abed, Souhail R.

    2009-01-01

    Sorption of polychlorinated biphenyls (PCBs) to sediment is a key process in determining their mobility, bioavailability, and chemical decomposition in aquatic environments. In order to examine the validity of currently used interpretation approaches for PCBs sorption, comparative results on 2-chlorobiphenyl sorption to carbonaceous components in sediments (activated carbon, carbon black, coal, soot, graphite, flyash, wood) were macroscopically correlated with the structural, morphological, crystallographic, and compositional properties of the carbonaceous components. Since the Freundlich sorption constant, K F (L kg -1 ) spanned several orders of magnitude, ranging from log K F of 6.13-5.27 for activated carbon, 5.04 for carbon black, 3.83 for coal to 3.08 for wood, organic carbon partitioning approach should be more specifically categorized, considering the various forms, nature and origins of organic carbon in sediment. Sorption rate constants and fraction parameters, which were numerically defined from empirical kinetic model with fast and slow sorption fractions, were closely related to the physicochemical properties of the carbonaceous components. Sorption interpretation approaches with a specific property and viewpoint, such as organic carbon partitioning, soot carbon distribution, or surface area correlation, did not properly explain the overall results on sorption capacity, fast and slow sorption kinetics, and partitioning coefficient. It is also important to emphasize the heterogeneous nature of sediment and the difficulties of encompassing the partitioning among its carbonaceous components.

  20. PCB congener sorption to carbonaceous sediment components: Macroscopic comparison and characterization of sorption kinetics and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyeok [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States); Al-Abed, Souhail R., E-mail: al-abed.souhail@epa.gov [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States)

    2009-06-15

    Sorption of polychlorinated biphenyls (PCBs) to sediment is a key process in determining their mobility, bioavailability, and chemical decomposition in aquatic environments. In order to examine the validity of currently used interpretation approaches for PCBs sorption, comparative results on 2-chlorobiphenyl sorption to carbonaceous components in sediments (activated carbon, carbon black, coal, soot, graphite, flyash, wood) were macroscopically correlated with the structural, morphological, crystallographic, and compositional properties of the carbonaceous components. Since the Freundlich sorption constant, K{sub F} (L kg{sup -1}) spanned several orders of magnitude, ranging from log K{sub F} of 6.13-5.27 for activated carbon, 5.04 for carbon black, 3.83 for coal to 3.08 for wood, organic carbon partitioning approach should be more specifically categorized, considering the various forms, nature and origins of organic carbon in sediment. Sorption rate constants and fraction parameters, which were numerically defined from empirical kinetic model with fast and slow sorption fractions, were closely related to the physicochemical properties of the carbonaceous components. Sorption interpretation approaches with a specific property and viewpoint, such as organic carbon partitioning, soot carbon distribution, or surface area correlation, did not properly explain the overall results on sorption capacity, fast and slow sorption kinetics, and partitioning coefficient. It is also important to emphasize the heterogeneous nature of sediment and the difficulties of encompassing the partitioning among its carbonaceous components.

  1. A macroscopic model to simulate the mechanically induced martensitic transformation in metastable austenitic stainless steels

    NARCIS (Netherlands)

    Perdahcioglu, Emin Semih; Geijselaers, Hubertus J.M.

    2012-01-01

    Mechanically induced martensitic transformation and the associated transformation plasticity phenomena in austenitic stainless steels are studied. The mechanisms responsible for the transformation are investigated and put into perspective based on experimental evidence. The stress and strain

  2. Neural mechanisms of speed perception: transparent motion

    NARCIS (Netherlands)

    Krekelberg, Bart; van Wezel, Richard Jack Anton

    2013-01-01

    Visual motion on the macaque retina is processed by direction- and speed-selective neurons in extrastriate middle temporal cortex (MT). There is strong evidence for a link between the activity of these neurons and direction perception. However, there is conflicting evidence for a link between speed

  3. Schroedinger’s Mirrors - exploring mechanical motion in the quantum regime

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    The quantum optical control of solid-state mechanical devices, quantum optomechanics, has emerged as a new frontier of light-matter interactions. Devices currently under investigation cover a mass range of more than 17 orders of magnitude - from nanomechanical waveguides of some picograms to macroscopic, kilogram-weight mirrors of gravitational wave detectors. This development has been enabled by the insight that quantum optics provides a powerful toolbox to generate, manipulate and detect quantum states of mechanical motion, in particular by coupling the mechanics to an optical or microwave cavity field. Originally, such cavity optomechanical systems have been studied from the early 1970s on in the context of gravitational wave antennas. Advancements in micro-fabrication and micro-cavities, however, have resulted in the development of a completely new generation of nano- and micro-optomechanical devices. Today, 10 years after the first demonstrations of laser cooling of micromechanical resonators, the quantu...

  4. A macroscopic model to simulate the mechanically induced martensitic transformation in metastable austenitic stainless steels

    International Nuclear Information System (INIS)

    Perdahcıoğlu, E.S.; Geijselaers, H.J.M.

    2012-01-01

    Mechanically induced martensitic transformation and the associated transformation plasticity phenomena in austenitic stainless steels are studied. The mechanisms responsible for the transformation are investigated and put into perspective based on experimental evidence. The stress and strain partitioning into the austenite and martensite phases are formulated using a mean-field homogenization approach. At this intermediate length-scale the average stress in the austenite phase is computed and utilized to compute the mechanical driving force resolved in the material. The amount of transformation and the transformation plasticity is derived as a function of the driving force. The mechanical response of the material is obtained by combining the homogenization and the transformation models. The model is verified by mechanical tests under biaxial loading conditions during which different transformation rates are observed. As a final verification of the model, a bending test is used which manifests the stress-state dependency of the transformation.

  5. Macroscopic Entangled State Generation with Optomechanical Coupling of Two Mechanical Modes

    Science.gov (United States)

    Weaver, Matthew; Luna, Fernando; Buters, Frank; Heeck, Kier; de Man, Sven; Bouwmeester, Dirk

    Mechanical resonators with a large quantum position uncertainty are an excellent test system for proposed decoherence mechanisms in massive systems. We present a scheme to optomechanically entangle two mechanical resonators with large frequency separation via two tone driving and single photon projection measurements. The quantum position uncertainty can be tuned with a variable optical pulse displacement operation, and independent single photon readout of the two resonators provides robust verification of the quantum states of the system. This scheme is currently experimentally feasible in a number of high mass opto- and electro-mechanical systems. We demonstrate one such system with two spatially and frequency separated Si3N4 trampoline resonators. We also show how the resonators can be coupled with two tone driving and the single photon optomechanical coupling rates can be tuned.

  6. Generation of macroscopic magnetic-field-aligned electric fields by the convection surge ion acceleratiom mechanism

    International Nuclear Information System (INIS)

    Mauk, B.H.

    1989-01-01

    The ''convection surge'' computer model presented previously (concerning the dramatic, nonadiabatic, magnetic-field-aligned energization of ions near the Earth's geosynchronous orbit in the presence of strong, transient, magnetic-field-perpendicular inductive electric fields) has been extended to include the self-consistent generation of magnetic-field-aligned electric fields. The field-aligned electric potential is obtained by imposing the quasi-neutrality condition using approximated electron distribution forms. The ions are forced to respond self-consistently to this potential. It is found that field-aligned potential drops up to 1 to 10 kV can be generated depending on electron temperatures and on the mass species of the ions. During transient periods of the process, these large potential drops can be confined to a few degrees of magnetic latitude at positions close to the magnetic equator. Anomalous, sometimes dramatic, additional magnetic-field-aligned ion acceleration also occurs in part as a result of a quasi-resonance between the parallel velocities of some ions and the propagating electric potential fronts. It is speculated that the convection surge mechanism could be a key player in the transient, field-aligned electromagnetic processes observed to operate within the middle (e.g., geosynchronous) magnetosphere. copyright American Geophysical Union 1989

  7. Interpretation of macroscopic quantum phenomena

    International Nuclear Information System (INIS)

    Baumann, K.

    1986-01-01

    It is argued that a quantum theory without observer is required for the interpretation of macroscopic quantum tunnelling. Such a theory is obtained by augmenting QED by the actual electric field in the rest system of the universe. An equation of the motion of this field is formulated form which the correct macroscopic behavior of the universe and the validity of the Born interpretation is derived. Care is taken to use mathematically sound concepts only. (Author)

  8. PLANAR MECHANISMS USED FOR GENERATING CURVE LINE TRANSLATION MOTION

    Directory of Open Access Journals (Sweden)

    Ovidiu ANTONESCU

    2015-05-01

    Full Text Available The curve line translation motion can be generated in the particular form of the circular translation, through mono-mobile mechanisms with articulated links of simple parallelogram type (with a fixed side or through transmission with toothed belt with a fixed wheel. Also, the circular translation can be generated through planar mechanisms with two cylindrical gears with a fixed central wheel. It is mentioned that the two cylindrical gearings of the Fergusson mechanisms are both exterior and interior.

  9. Mechanism of charge recombination in meso-structured organic-inorganic hybrid perovskite solar cells: A macroscopic perspective

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wenchao; Yao, Yao, E-mail: yaoyao@fudan.edu.cn; Wu, Chang-Qin, E-mail: cqw@fudan.edu.cn [State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China); Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433 (China)

    2015-04-21

    In the currently popular organic-inorganic hybrid perovskite solar cells, the slowness of the charge recombination processes is found to be a key factor for contributing to their high efficiencies and high open circuit voltages, but the underlying recombination mechanism remains unclear. In this work, we investigate the bimolecular recombination (BR) and the trap-assisted monomolecular recombination (MR) in meso-structured perovskite solar cells under steady state working condition, and try to reveal their roles on determining the device performance. Some interfacial effects such as the injection barriers at the selective contacts are examined as well. Based on the macroscopic device modeling, the recombination resistance-voltage (R{sub rec}−V) and the current density-voltage (J–V) curves are calculated to characterize the recombination mechanism and describe the device performance, respectively. Through comparison with the impedance spectroscopy extracted R{sub rec} data, it is found that under the typical BR reduction factor and deep trap densities observed in experiments, the MR dominates the charge recombination in the low voltage regime, while the BR dominates in the high voltage regime. The short circuit current and the fill factor could be reduced by the significant MR but the open circuit voltage is generally determined by the BR. The different electron injection barriers at the contact can change the BR rate and induce different patterns for the R{sub rec}–V characteristics. For the perovskites of increased band gaps, the R{sub rec}'s are significantly enhanced, corresponding to the high open circuit voltages. Finally, it is revealed that the reduced effective charge mobility due to the transport in electron and hole transporting material makes the R{sub rec} decrease slowly with the increasing voltage, which leads to increased open circuit voltage.

  10. Hybrid magnetic mechanism for active locomotion based on inchworm motion

    International Nuclear Information System (INIS)

    Kim, Sung Hoon; Hashi, Shuichiro; Ishiyama, Kazushi

    2013-01-01

    Magnetic robots have been studied in the past. Insect-type micro-robots are used in various biomedical applications; researchers have developed inchworm micro-robots for endoscopic use. A biological inchworm has a looping locomotion gait. However, most inchworm micro-robots depend on a general bending, or bellows, motion. In this paper, we introduce a new robotic mechanism using magnetic force and torque control in a rotating magnetic field for a looping gait. The proposed robot is controlled by the magnetic torque, attractive force, and body mechanisms (two stoppers, flexible body, and different frictional legs). The magnetic torque generates a general bending motion. In addition, the attractive force and body mechanisms produce the robot’s looping motion within a rotating magnetic field and without the use of an algorithm for field control. We verified the device’s performance and analyzed the motion through simulations and various experiments. The robot mechanism can be applied to active locomotion for various medical robots, such as wireless endoscopes. (technical note)

  11. Energy-harvesting shock absorber with a mechanical motion rectifier

    Science.gov (United States)

    Li, Zhongjie; Zuo, Lei; Kuang, Jian; Luhrs, George

    2013-02-01

    Energy-harvesting shock absorbers are able to recover the energy otherwise dissipated in the suspension vibration while simultaneously suppressing the vibration induced by road roughness. They can work as a controllable damper as well as an energy generator. An innovative design of regenerative shock absorbers is proposed in this paper, with the advantage of significantly improving the energy harvesting efficiency and reducing the impact forces caused by oscillation. The key component is a unique motion mechanism, which we called ‘mechanical motion rectifier (MMR)’, to convert the oscillatory vibration into unidirectional rotation of the generator. An implementation of a MMR-based harvester with high compactness is introduced and prototyped. A dynamic model is created to analyze the general properties of the motion rectifier by making an analogy between mechanical systems and electrical circuits. The model is capable of analyzing electrical and mechanical components at the same time. Both simulation and experiments are carried out to verify the modeling and the advantages. The prototype achieved over 60% efficiency at high frequency, much better than conventional regenerative shock absorbers in oscillatory motion. Furthermore, road tests are done to demonstrate the feasibility of the MMR shock absorber, in which more than 15 Watts of electricity is harvested while driving at 15 mph on a smooth paved road. The MMR-based design can also be used for other applications of vibration energy harvesting, such as from tall buildings or long bridges.

  12. Energy-harvesting shock absorber with a mechanical motion rectifier

    International Nuclear Information System (INIS)

    Li, Zhongjie; Zuo, Lei; Kuang, Jian; Luhrs, George

    2013-01-01

    Energy-harvesting shock absorbers are able to recover the energy otherwise dissipated in the suspension vibration while simultaneously suppressing the vibration induced by road roughness. They can work as a controllable damper as well as an energy generator. An innovative design of regenerative shock absorbers is proposed in this paper, with the advantage of significantly improving the energy harvesting efficiency and reducing the impact forces caused by oscillation. The key component is a unique motion mechanism, which we called ‘mechanical motion rectifier (MMR)’, to convert the oscillatory vibration into unidirectional rotation of the generator. An implementation of a MMR-based harvester with high compactness is introduced and prototyped. A dynamic model is created to analyze the general properties of the motion rectifier by making an analogy between mechanical systems and electrical circuits. The model is capable of analyzing electrical and mechanical components at the same time. Both simulation and experiments are carried out to verify the modeling and the advantages. The prototype achieved over 60% efficiency at high frequency, much better than conventional regenerative shock absorbers in oscillatory motion. Furthermore, road tests are done to demonstrate the feasibility of the MMR shock absorber, in which more than 15 Watts of electricity is harvested while driving at 15 mph on a smooth paved road. The MMR-based design can also be used for other applications of vibration energy harvesting, such as from tall buildings or long bridges. (paper)

  13. Mechanical design of NASA Ames Research Center vertical motion simulator

    Science.gov (United States)

    Engelbert, D. F.; Bakke, A. P.; Chargin, M. K.; Vallotton, W. C.

    1976-01-01

    NASA has designed and is constructing a new flight simulator with large vertical travel. Several aspects of the mechanical design of this Vertical Motion Simulator (VMS) are discussed, including the multiple rack and pinion vertical drive, a pneumatic equilibration system, and the friction-damped rigid link catenaries used as cable supports.

  14. Distinct neural mechanisms for body form and body motion discriminations

    NARCIS (Netherlands)

    Vangeneugden, Joris; Peelen, Marius V; Tadin, Duje; Battelli, Lorella

    2014-01-01

    Actions can be understood based on form cues (e.g., static body posture) as well as motion cues (e.g., gait patterns). A fundamental debate centers on the question of whether the functional and neural mechanisms processing these two types of cues are dissociable. Here, using fMRI, psychophysics, and

  15. Port-Hamiltonian approaches to motion generation for mechanical systems

    NARCIS (Netherlands)

    Sakai, Satoru; Stramigioli, Stefano

    This paper gives new motion generation methods for mechanical port-Hamiltonian systems. First, we propose a generation method based on an asymptotic stabilization method without damping assignment. This asymptotic stabilization method preserves the Hamiltonian structure in the closed-loop system

  16. Design and construction of a planar motion mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Tanasovici, Gilberto [Protemaq Engenharia e Projetos, Santo Andre, SP (Brazil); Fucatu, Carlos H. [Technomar Engenharia Ltda., Sao Paulo, SP (Brazil); Tannuri, Eduardo A. [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Mecatronica; Umeda, Carlos H. [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil)

    2008-07-01

    This paper describes the design and construction of a PMM (Planar Motion Mechanism) towed by the IPT-SP main carriage. The IPT towing tank no. 2 is 220 m length and 6.6 m wide. The PMM provides a forced sway and/or yaw oscillation on a ship or other marine structure scaled model.. The maximum sway amplitude (transversal motion) is {+-}1 m, and the maximum sway velocity is 1.0 m/s, with a maximum carrying load of 1000 N. The maximum yaw velocity (rotation motion) is 36 deg/s. High-precision components were used in the construction, and the final estimated accuracy in the sway axis is 0.02 mm and approximately 0.1 deg for yaw motions. Finite Element Analysis and Structural Optimization techniques were used during the design stage. The PMM structure total mass is less than 1 ton, lighter than similar mechanisms in other institutions. A Man-Machine Interface was developed, and the operator is able to define the period and amplitude of sway and yaw motions, as well as the fade-in and fade-out time. An integral 3-component force load cell is installed in the end of the support axis, which measures the hydrodynamic loads on the captive model at low speed tests. This novel laboratorial facility allows the IPT to execute new kinds of experimental procedures, related to evaluation of hydrodynamic loads acting on ship hulls and offshore structures. (author)

  17. Superposition and macroscopic observation

    International Nuclear Information System (INIS)

    Cartwright, N.D.

    1976-01-01

    The principle of superposition has long plagued the quantum mechanics of macroscopic bodies. In at least one well-known situation - that of measurement - quantum mechanics predicts a superposition. It is customary to try to reconcile macroscopic reality and quantum mechanics by reducing the superposition to a mixture. To establish consistency with quantum mechanics, values for the apparatus after a measurement are to be distributed in the way predicted by the superposition. The distributions observed, however, are those of the mixture. The statistical predictions of quantum mechanics, it appears, are not borne out by observation in macroscopic situations. It has been shown that, insofar as specific ergodic hypotheses apply to the apparatus after the interaction, the superposition which evolves is experimentally indistinguishable from the corresponding mixture. In this paper an idealized model of the measuring situation is presented in which this consistency can be demonstrated. It includes a simplified version of the measurement solution proposed by Daneri, Loinger, and Prosperi (1962). The model should make clear the kind of statistical evidence required to carry of this approach, and the role of the ergodic hypotheses assumed. (Auth.)

  18. Suppressive mechanisms in visual motion processing: From perception to intelligence.

    Science.gov (United States)

    Tadin, Duje

    2015-10-01

    Perception operates on an immense amount of incoming information that greatly exceeds the brain's processing capacity. Because of this fundamental limitation, the ability to suppress irrelevant information is a key determinant of perceptual efficiency. Here, I will review a series of studies investigating suppressive mechanisms in visual motion processing, namely perceptual suppression of large, background-like motions. These spatial suppression mechanisms are adaptive, operating only when sensory inputs are sufficiently robust to guarantee visibility. Converging correlational and causal evidence links these behavioral results with inhibitory center-surround mechanisms, namely those in cortical area MT. Spatial suppression is abnormally weak in several special populations, including the elderly and individuals with schizophrenia-a deficit that is evidenced by better-than-normal direction discriminations of large moving stimuli. Theoretical work shows that this abnormal weakening of spatial suppression should result in motion segregation deficits, but direct behavioral support of this hypothesis is lacking. Finally, I will argue that the ability to suppress information is a fundamental neural process that applies not only to perception but also to cognition in general. Supporting this argument, I will discuss recent research that shows individual differences in spatial suppression of motion signals strongly predict individual variations in IQ scores. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. PRECISION MOTION SYSTEM FOR OPTO-MECHANICAL EQUIPMENT OF MICROELECTRONICS

    Directory of Open Access Journals (Sweden)

    I. V. Dainiak

    2015-01-01

    Full Text Available The paper proposes a structure of precision motion system built on the basis of a circular multi-coordinate synchronous segment motor and reconfigurable parallel kinematic mechanism. The multi-coordinate synchronous segment motor may have from two to six movable segments depending on the design, and number of the segments generally defines an internal mobility of the motor. A specific feature of the parallel kinematic mechanism consists in the possibility of its structure reconfiguration by serial connection of two neighboring rods with the help of free elements of their spherical joints into triangular circuits with one spherical hinge at the common vertex. As result of this, the controlled motion of motor movable segments is transformed into the complex spatial displacement of circular platform with number of degrees of freedom up to six inclusively.A mathematical model for solution of the kinematic problem in the investigated parallel mechanism has been offered in the paper. The model allows to calculate a position of movable segments of multi-coordinate synchronous motor depending on the desired position and orientation of the executive circular platform. The parametric definition of base point positions in the motor segments in time allows eventually to form algorithms of programmable motions.The paper substantiates ability to embed the developed motion system into projection unit of opto-mechanical equipment while preserving traditional configuration scheme. This provides the possibility of adaptive adjustment of optical elements during operation; it allows to adjust the optical elements when the geometry of projection system is changed due to deterioration. As result, main characteristics of projection system: resolution, depth of field and image contrast and distortion are maintained at the required level. The developed motion system can be used as a coordinate system of positioning, alignment and scanning in the assembly and other

  20. Superconductivity and macroscopic quantum phenomena

    International Nuclear Information System (INIS)

    Rogovin, D.; Scully, M.

    1976-01-01

    It is often asserted that superconducting systems are manifestations of quantum mechanics on a macroscopic scale. In this review article it is demonstrated that this quantum assertion is true within the framework of the microscopic theory of superconductivity. (Auth.)

  1. Motion laws synthesis for cam mechanisms with multiple follower displacement

    Science.gov (United States)

    Podgornyj, Yu I.; Skeeba, V. Yu; Kirillov, A. V.; Martynova, T. G.; Skeeba, P. Yu

    2018-03-01

    The research discusses the cam mechanisms design. The analysis of specialized literature indicates that the synthesis of the cam mechanisms laws of motion is currently done mainly by a standard set of acceleration curves. In some cases, the designer needs to synthesize a new acceleration law which should be task-specific and enforce a certain production step. The values of the technological loads and inertia forces loads generated by the mechanism are calculated to analyze the slay mechanism behavior in the production of closely woven fabrics. Mathematical packages MathCad and SolidWorks are used in calculations. As a result of the research, the authors propose the methodology for synthesizing the slay mechanism with multiple follower displacements for the point of contact between the reed and the fabric edge. Theoretical studies have been tested on a specific machine model (STB loom). The authors have synthesized the motion law of the filling threads beat-up mechanism for the production of strong fabrics. New basic and closing cam profiles are proposed. The results are designed to enhance the possibilities of the looms and to recommend the most efficient equipment operation modes for the producers.

  2. Macroscopic Optomechanically Induced Transparency

    Science.gov (United States)

    Pate, Jacob; Castelli, Alessandro; Martinez, Luis; Thompson, Johnathon; Chiao, Ray; Sharping, Jay

    Optomechanically induced transparency (OMIT) is an effect wherein the spectrum of a cavity resonance is modified through interference between coupled excitation pathways. In this work we investigate a macroscopic, 3D microwave, superconducting radio frequency (SRF) cavity incorporating a niobium-coated, silicon-nitride membrane as the flexible boundary. The boundary supports acoustic vibrational resonances, which lead to coupling with the microwave resonances of the SRF cavity. The theoretical development and physical understanding of OMIT for our macroscopic SRF cavity is the same as that for other recently-reported OMIT systems despite vastly different optomechanical coupling factors and device sizes. Our mechanical oscillator has a coupling factor of g0 = 2 π . 1 ×10-5 Hz and is roughly 38 mm in diameter. The Q = 5 ×107 for the SRF cavity allows probing of optomechanical effects in the resolved sideband regime.

  3. Quantum equilibria for macroscopic systems

    International Nuclear Information System (INIS)

    Grib, A; Khrennikov, A; Parfionov, G; Starkov, K

    2006-01-01

    Nash equilibria are found for some quantum games with particles with spin-1/2 for which two spin projections on different directions in space are measured. Examples of macroscopic games with the same equilibria are given. Mixed strategies for participants of these games are calculated using probability amplitudes according to the rules of quantum mechanics in spite of the macroscopic nature of the game and absence of Planck's constant. A possible role of quantum logical lattices for the existence of macroscopic quantum equilibria is discussed. Some examples for spin-1 cases are also considered

  4. Quantum equilibria for macroscopic systems

    Energy Technology Data Exchange (ETDEWEB)

    Grib, A [Department of Theoretical Physics and Astronomy, Russian State Pedagogical University, St. Petersburg (Russian Federation); Khrennikov, A [Centre for Mathematical Modelling in Physics and Cognitive Sciences Vaexjoe University (Sweden); Parfionov, G [Department of Mathematics, St. Petersburg State University of Economics and Finances (Russian Federation); Starkov, K [Department of Mathematics, St. Petersburg State University of Economics and Finances (Russian Federation)

    2006-06-30

    Nash equilibria are found for some quantum games with particles with spin-1/2 for which two spin projections on different directions in space are measured. Examples of macroscopic games with the same equilibria are given. Mixed strategies for participants of these games are calculated using probability amplitudes according to the rules of quantum mechanics in spite of the macroscopic nature of the game and absence of Planck's constant. A possible role of quantum logical lattices for the existence of macroscopic quantum equilibria is discussed. Some examples for spin-1 cases are also considered.

  5. Mechanical Assessment of the Waste Package Subject to Vibratory Motion

    Energy Technology Data Exchange (ETDEWEB)

    M. Gross

    2004-10-14

    The purpose of this document is to provide an integrated overview of the calculation reports that define the response of the waste package and its internals to vibratory ground motion. The calculation reports for waste package response to vibratory ground motion are identified in Table 1-1. Three key calculation reports describe the potential for mechanical damage to the waste package, fuel assemblies, and cladding from a seismic event. Three supporting documents have also been published to investigate sensitivity of damage to various assumptions for the calculations. While these individual reports present information on a specific aspect of waste package and cladding response, they do not describe the interrelationship between the various calculations and the relationship of this information to the seismic scenario class for Total System Performance Assessment-License Application (TSPA-LA). This report is designed to fill this gap by providing an overview of the waste package structural response calculations.

  6. Mechanical Assessment of the Waste Package Subject to Vibratory Motion

    International Nuclear Information System (INIS)

    M. Gross

    2004-01-01

    The purpose of this document is to provide an integrated overview of the calculation reports that define the response of the waste package and its internals to vibratory ground motion. The calculation reports for waste package response to vibratory ground motion are identified in Table 1-1. Three key calculation reports describe the potential for mechanical damage to the waste package, fuel assemblies, and cladding from a seismic event. Three supporting documents have also been published to investigate sensitivity of damage to various assumptions for the calculations. While these individual reports present information on a specific aspect of waste package and cladding response, they do not describe the interrelationship between the various calculations and the relationship of this information to the seismic scenario class for Total System Performance Assessment-License Application (TSPA-LA). This report is designed to fill this gap by providing an overview of the waste package structural response calculations

  7. Time-dependent reliability sensitivity analysis of motion mechanisms

    International Nuclear Information System (INIS)

    Wei, Pengfei; Song, Jingwen; Lu, Zhenzhou; Yue, Zhufeng

    2016-01-01

    Reliability sensitivity analysis aims at identifying the source of structure/mechanism failure, and quantifying the effects of each random source or their distribution parameters on failure probability or reliability. In this paper, the time-dependent parametric reliability sensitivity (PRS) analysis as well as the global reliability sensitivity (GRS) analysis is introduced for the motion mechanisms. The PRS indices are defined as the partial derivatives of the time-dependent reliability w.r.t. the distribution parameters of each random input variable, and they quantify the effect of the small change of each distribution parameter on the time-dependent reliability. The GRS indices are defined for quantifying the individual, interaction and total contributions of the uncertainty in each random input variable to the time-dependent reliability. The envelope function method combined with the first order approximation of the motion error function is introduced for efficiently estimating the time-dependent PRS and GRS indices. Both the time-dependent PRS and GRS analysis techniques can be especially useful for reliability-based design. This significance of the proposed methods as well as the effectiveness of the envelope function method for estimating the time-dependent PRS and GRS indices are demonstrated with a four-bar mechanism and a car rack-and-pinion steering linkage. - Highlights: • Time-dependent parametric reliability sensitivity analysis is presented. • Time-dependent global reliability sensitivity analysis is presented for mechanisms. • The proposed method is especially useful for enhancing the kinematic reliability. • An envelope method is introduced for efficiently implementing the proposed methods. • The proposed method is demonstrated by two real planar mechanisms.

  8. Mechanisms of selective attention and space motion sickness

    Science.gov (United States)

    Kohl, R. L.

    1987-01-01

    The neural mismatch theory of space motion sickness asserts that the central and peripheral autonomic sequelae of discordant sensory input arise from central integrative processes falling to reconcile patterns of incoming sensory information with existing memory. Stated differently, perceived novelty reaches a stress level as integrative mechanisms fail to return a sense of control to the individual in the new environment. Based on evidence summarized here, the severity of the neural mismatch may be dependent upon the relative amount of attention selectively afforded to each sensory input competing for control of behavior. Components of the limbic system may play important roles in match-mismatch operations, be therapeutically modulated by antimotion sickness drugs, and be optimally positioned to control autonomic output.

  9. Macroscopic and microscopic description of HE-HI collisions; classical equations of motion calculations. [Rapidity, cross sections, central and noncentral collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bodmer, A. R.

    1978-01-01

    The study of high energy heavy ion reactions includes the three principle a priori approaches used for central collisions, namely, hydrodynamics, cascade--Boltzman equation, and the classical equations of motion. While no clearly justified central or near central collisions are found, the classical equations of motion are used to illustrate some general features of these reactions. It is expected that the hot nuclear matter produced in such collisions is a dense, viscous, and thermally conductive fluid with important nonequilibrium and nonclassical features, rapidity, distribution, noncentral collisions, potential dependent effects for a given two-body scattering, and c.m. cross sections for a central collision with given parameters are among the properties considered. 12 references. (JFP)

  10. Behavior and mechanism of Ni(II) uptake on MnO2 by a combination of macroscopic and EXAFS investigation

    International Nuclear Information System (INIS)

    Guodong Sheng; Jiang Sheng; Shitong Yang; Ju Hu; Xiangke Wang

    2011-01-01

    The effects of pH, ionic strength, competing ions and initial metal concentrations on the uptake behavior and mechanism of radioactive Ni(II) onto MnO 2 was investigated using a combination of classical macroscopic methods and the extended X-ray absorption fine structure (EXAFS) spectroscopy technique. The results indicated that the uptake of Ni(II) on MnO 2 is obviously dependent on pH but independent of ionic strength, which suggested that the uptake of Ni(II) onto MnO 2 is attributed to an inner-sphere surface complex rather than an outer-sphere surface complex. EXAFS analysis shows that the hydrated Ni(II) is adsorbed through six-fold coordination with an average Ni-O interatomic distance of 2.04 ± 0.01 A. It can be inferred from the EXAFS analysis that the inner-sphere surface complex of Ni(II) onto MnO 2 is involved in both edge-sharing and corner-sharing linkages. Both the macroscopic uptake data and the molecular level evidence of Ni(II) surface speciation at the MnO 2 -water interfaces should be factored into better prediction of the bioavailability and mobility of Ni(II) in soil and water environment. (author)

  11. Neural Mechanisms of Illusory Motion: Evidence from ERP Study

    Directory of Open Access Journals (Sweden)

    Xu Y. A. N. Yun

    2011-05-01

    Full Text Available ERPs were used to examine the neural correlates of illusory motion, by presenting the Rice Wave illusion (CI, its two variants (WI and NI and a real motion video (RM. Results showed that: Firstly, RM elicited a more negative deflection than CI, NI and WI between 200–350ms. Secondly, between 500–600ms, CI elicited a more positive deflection than NI and WI, and RM elicited a more positive deflection than CI, what's more interesting was the sequential enhancement of brain activity with the corresponding motion strength. We inferred that the former component might reflect the successful encoding of the local motion signals in detectors at the lower stage; while the latter one might be involved in the intensive representations of visual input in real/illusory motion perception, this was the whole motion-signal organization in the later stage of motion perception. Finally, between 1185–1450 ms, a significant positive component was found between illusory/real motion tasks than NI (no motion. Overall, we demonstrated that there was a stronger deflection under the corresponding lager motion strength. These results reflected not only the different temporal patterns between illusory and real motion but also extending to their distinguishing working memory representation and storage.

  12. Shape matters: Near-field fluid mechanics dominate the collective motions of ellipsoidal squirmers.

    Science.gov (United States)

    Kyoya, K; Matsunaga, D; Imai, Y; Omori, T; Ishikawa, T

    2015-12-01

    Microswimmers show a variety of collective motions. Despite extensive study, questions remain regarding the role of near-field fluid mechanics in collective motion. In this paper, we describe precisely the Stokes flow around hydrodynamically interacting ellipsoidal squirmers in a monolayer suspension. The results showed that various collective motions, such as ordering, aggregation, and whirls, are dominated by the swimming mode and the aspect ratio. The collective motions are mainly induced by near-field fluid mechanics, despite Stokes flow propagation over a long range. These results emphasize the importance of particle shape in collective motion.

  13. Tribological Processes of the Mechanisms of Free Motion of Impulsive Friction Variators

    Directory of Open Access Journals (Sweden)

    B. Nedic

    2010-12-01

    Full Text Available Free motion mechanism (FMM of the impulsive variators is one vital part in power transmiting of impulsive lever variators which oscillating motion of external envelope (coulisse converted in rotation movement of the output shaft. The elements of mechanism of free motion are exposed to friction and wear during the work, which may be extremely intensive in some cases. The paper analyzes the tribological processes on elements of free motion mechanism of impulsive friction variators with special report on wear of tribomehanical system: the external envelope (coulisse - roller and roller - shaft (star.

  14. A method of meta-mechanism combination and replacement based on motion study

    Directory of Open Access Journals (Sweden)

    Yadong Fang

    2015-01-01

    Full Text Available Lacking the effective methods to reduce labor and cost, many small- and medium-sized assembly companies are facing with the problem of high cost for a long time. In order to reduce costs of manual operations, the method of meta-mechanism combination and replacement is studied. In this paper, we mainly discuss assembling motion analysis, workpieces position information acquisition, motion library construction, assembling motion analysis by Maynard’s operation sequence technique, meta-mechanism database establishment, and match of motion and mechanism. At the same time, the principle, process, and system realization framework of mechanism replacement are introduced. Lastly, problems for low-cost automation of the production line are basically resolved by operator motion analysis and meta-mechanism combination and match.

  15. Statistical mechanical estimation of the free energy of formation of E. coli biomass for use with macroscopic bioreactor balances.

    Science.gov (United States)

    Grosz, R; Stephanopoulos, G

    1983-09-01

    The need for the determination of the free energy of formation of biomass in bioreactor second law balances is well established. A statistical mechanical method for the calculation of the free energy of formation of E. coli biomass is introduced. In this method, biomass is modelled to consist of a system of biopolymer networks. The partition function of this system is proposed to consist of acoustic and optical modes of vibration. Acoustic modes are described by Tarasov's model, the parameters of which are evaluated with the aid of low-temperature calorimetric data for the crystalline protein bovine chymotrypsinogen A. The optical modes are described by considering the low-temperature thermodynamic properties of biological monomer crystals such as amino acid crystals. Upper and lower bounds are placed on the entropy to establish the maximum error associated with the statistical method. The upper bound is determined by endowing the monomers in biomass with ideal gas properties. The lower bound is obtained by limiting the monomers to complete immobility. On this basis, the free energy of formation is fixed to within 10%. Proposals are made with regard to experimental verification of the calculated value and extension of the calculation to other types of biomass.

  16. General-relativistic celestial mechanics. II. Translational equations of motion

    International Nuclear Information System (INIS)

    Damour, T.; Soffel, M.; Xu, C.

    1992-01-01

    The translational laws of motion for gravitationally interacting systems of N arbitrarily composed and shaped, weakly self-gravitating, rotating, deformable bodies are obtained at the first post-Newtonian approximation of general relativity. The derivation uses our recently introduced multi-reference-system method and obtains the translational laws of motion by writing that, in the local center-of-mass frame of each body, relativistic inertial effects combine with post-Newtonian self- and externally generated gravitational forces to produce a global equilibrium (relativistic generalization of d'Alembert's principle). Within the first post-Newtonian approximation [i.e., neglecting terms of order (v/c) 4 in the equations of motion], our work is the first to obtain complete and explicit results, in the form of infinite series, for the laws of motion of arbitrarily composed and shaped bodies. We first obtain the laws of motion of each body as an infinite series exhibiting the coupling of all the (Blanchet-Damour) post-Newtonian multipole moments of this body to the post-Newtonian tidal moments (recently defined by us) felt by this body. We then give the explicit expression of these tidal moments in terms of post-Newtonian multipole moments of the other bodies

  17. Stirling engine power control and motion conversion mechanism

    Science.gov (United States)

    Marks, David T.

    1983-01-01

    A motion conversion device for converting between the reciprocating motion of the pistons in a Stirling engine and the rotating motion of its output shaft, and for changing the stroke and phase of the pistons, includes a lever pivoted at one end and having a cam follower at the other end. The piston rod engages the lever intermediate its ends and the cam follower engages a cam keyed to the output shaft. The lever pivot can be moved to change the length of the moment arm defined between the cam follower and the piston rod the change the piston stroke and force exerted on the cam, and the levers can be moved in opposite directions to change the phase between pistons.

  18. Macroscopic transport by synthetic molecular machines

    NARCIS (Netherlands)

    Berna, J; Leigh, DA; Lubomska, M; Mendoza, SM; Perez, EM; Rudolf, P; Teobaldi, G; Zerbetto, F

    Nature uses molecular motors and machines in virtually every significant biological process, but demonstrating that simpler artificial structures operating through the same gross mechanisms can be interfaced with - and perform physical tasks in - the macroscopic world represents a significant hurdle

  19. An Adaptive Neural Mechanism for Acoustic Motion Perception with Varying Sparsity.

    Science.gov (United States)

    Shaikh, Danish; Manoonpong, Poramate

    2017-01-01

    Biological motion-sensitive neural circuits are quite adept in perceiving the relative motion of a relevant stimulus. Motion perception is a fundamental ability in neural sensory processing and crucial in target tracking tasks. Tracking a stimulus entails the ability to perceive its motion, i.e., extracting information about its direction and velocity. Here we focus on auditory motion perception of sound stimuli, which is poorly understood as compared to its visual counterpart. In earlier work we have developed a bio-inspired neural learning mechanism for acoustic motion perception. The mechanism extracts directional information via a model of the peripheral auditory system of lizards. The mechanism uses only this directional information obtained via specific motor behaviour to learn the angular velocity of unoccluded sound stimuli in motion. In nature however the stimulus being tracked may be occluded by artefacts in the environment, such as an escaping prey momentarily disappearing behind a cover of trees. This article extends the earlier work by presenting a comparative investigation of auditory motion perception for unoccluded and occluded tonal sound stimuli with a frequency of 2.2 kHz in both simulation and practice. Three instances of each stimulus are employed, differing in their movement velocities-0.5°/time step, 1.0°/time step and 1.5°/time step. To validate the approach in practice, we implement the proposed neural mechanism on a wheeled mobile robot and evaluate its performance in auditory tracking.

  20. Two independent mechanisms for motion-in-depth perception: evidence from individual differences

    Directory of Open Access Journals (Sweden)

    Harold T Nefs

    2010-10-01

    Full Text Available Our forward-facing eyes allow us the advantage of binocular visual information: using the tiny differences between right and left eye views to learn about depth and location in three dimensions. Our visual systems also contain specialized mechanisms to detect motion-in-depth from binocular vision, but the nature of these mechanisms remains controversial. Binocular motion-in-depth perception could theoretically be based on first detecting binocular disparity and then monitoring how it changes over time. The alternative is to monitor the motion in the right and left eye separately and then compare these motion signals. Here we used an individual differences approach to test whether the two sources of information are processed via dissociated mechanisms, and to measure the relative importance of those mechanisms. Our results suggest the existence of two distinct mechanisms, each contributing to the perception of motion in depth in most observers. Additionally, for the first time, we demonstrate the relative prevalence of the two mechanisms within a normal population. In general, visual systems appear to rely mostly on the mechanism sensitive to changing binocular disparity, but perception of motion in depth is augmented by the presence of a less sensitive mechanism that uses interocular velocity differences. Occasionally, we find observers with the opposite pattern of sensitivity. More generally this work showcases the power of the individual differences approach in studying the functional organisation of cognitive systems.

  1. On the Motion of solids in modified quantum mechanics

    International Nuclear Information System (INIS)

    Diosi, L.

    1988-01-01

    In this paper we apply the unified dynamics of Ghirardi, Rimini and Weber to the translational and rotational motion of solids in three dimensions. We show that, in a certain approximation, the rotational equations can formally be reduced to the translational ones already known. We point out that the rotation of solids as well as their translation are practically of classical nature without any observable quantum effects

  2. Quantum mechanical equations of particle and spin motion in polarised medium

    International Nuclear Information System (INIS)

    Silenko, A.Ya.

    2003-01-01

    The quantum mechanical equations for the particles and spin motion in the media with polarized electrons by presence of the external fields are determined. The motion of the electrons and their spin are influenced by the exchange interaction whereas the motion of the positrons is the annihilation one. The second order summands by spin are accounted for the particles with the S≥1 spin. The obtained equations may applied for describing the particles and spin motion both in the magnetic and nonmagnetic media [ru

  3. A Mechanical Analogy for Ohm's Law.

    Science.gov (United States)

    do Couto Tavares, Milton; And Others

    1991-01-01

    A mechanical analogy between the microscopic motion of a charged carrier in an ordinary resistor and the macroscopic motion of a ball falling along a slanted board covered with a lattice of nails is introduced. The Drude model is also introduced to include the case of inelastic collisions. Computer simulation of the motion is described. (KR)

  4. The application of biofluid mechanics boundary effects on phoretic motions of colloidal spheres

    CERN Document Server

    Chen, Po-Yuan

    2014-01-01

    "The Application of Biofluid Mechanics: Boundary Effects on Phoretic Motions of Colloidal Spheres" focuses on the phoretic motion behavior of various micron- to nanometer-size particles. The content of this book is divided into two parts: one on the concentration gradient-driven diffusiophoresis and osmophoresis, and one on thermocapillary motion and thermophoretic motion driven by temperature gradient. Diffusiophoresis and osmophoresis are mainly used in biomedical engineering applications, such as drug delivery, purification, and the description of the behavior of the immune system; thermocapillary motion and thermophoretic motion are applied in the field of semiconductors, as well as in suspended impurities removal. The book also provides a variety of computer programming source codes compiled using Fortran for researchers' future applications. This book is intended for chemical engineers, biomedical engineers and scientists, biophysicists, and fundamental chemotaxis researchers. Dr. Po-Yuan Chen is an Ass...

  5. Neural mechanisms underlying sound-induced visual motion perception: An fMRI study.

    Science.gov (United States)

    Hidaka, Souta; Higuchi, Satomi; Teramoto, Wataru; Sugita, Yoichi

    2017-07-01

    Studies of crossmodal interactions in motion perception have reported activation in several brain areas, including those related to motion processing and/or sensory association, in response to multimodal (e.g., visual and auditory) stimuli that were both in motion. Recent studies have demonstrated that sounds can trigger illusory visual apparent motion to static visual stimuli (sound-induced visual motion: SIVM): A visual stimulus blinking at a fixed location is perceived to be moving laterally when an alternating left-right sound is also present. Here, we investigated brain activity related to the perception of SIVM using a 7T functional magnetic resonance imaging technique. Specifically, we focused on the patterns of neural activities in SIVM and visually induced visual apparent motion (VIVM). We observed shared activations in the middle occipital area (V5/hMT), which is thought to be involved in visual motion processing, for SIVM and VIVM. Moreover, as compared to VIVM, SIVM resulted in greater activation in the superior temporal area and dominant functional connectivity between the V5/hMT area and the areas related to auditory and crossmodal motion processing. These findings indicate that similar but partially different neural mechanisms could be involved in auditory-induced and visually-induced motion perception, and neural signals in auditory, visual, and, crossmodal motion processing areas closely and directly interact in the perception of SIVM. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Gravitational Self-Force: Orbital Mechanics Beyond Geodesic Motion

    Science.gov (United States)

    Barack, Leor

    The question of motion in a gravitationally bound two-body system is a longstanding open problem of General Relativity. When the mass ratio eta; is small, the problem lends itself to a perturbative treatment, wherein corrections to the geodesic motion of the smaller object (due to radiation reaction, internal structure, etc.) are accounted for order by order in η, using the language of an effective gravitational self-force. The prospect for observing gravitational waves from compact objects inspiralling into massive black holes in the foreseeable future has in the past 15 years motivated a program to obtain a rigorous formulation of the self-force and compute it for astrophysically interesting systems. I will give a brief survey of this activity and its achievements so far, and will identify the challenges that lie ahead. As concrete examples, I will discuss recent calculations of certain conservative post-geodesic effects of the self-force, including the O(η ) correction to the precession rate of the periastron. I will highlight the way in which such calculations allow us to make a fruitful contact with other approaches to the two-body problem.

  7. GEOMETRIC PROPERTIES OF A MECHANICAL FORWARD MOTION COMPENSATION SYSTEM CONTROLLED BY A PIEZOELECTRIC DRIVE

    Directory of Open Access Journals (Sweden)

    F. Collette

    2012-07-01

    Full Text Available Forward Motion Compensation (FMC systems have been designed to ensure the radiometric quality of motion acquisition in airborne cameras. If the radiometric benefits of FMC have been acknowledged, what are its effects on the geometrical properties of the camera? This paper demonstrates that FMC significantly improves geometrical properties of a camera. Aspects of FMC theory are discussed, with a focus on the near-lossless implementation of this technology into digital aerial camera systems. Among mechanical FMC technologies, the piezoelectric drive is proving to excel in dynamic positioning in both accuracy and repeatability. The patented piezoelectric drive integrated into Optech aerial camera systems allows for continuous and precise sensor motion to ensure exact compensation of the aircraft's forward motion. This paper presents findings that demonstrate the validity of this assertion. The paper also discusses the physical principles involved in motion acquisition. Equations are included that define the motion effect at image level and illustrate how FMC acts to prevent motion effects. The residual motion effect or compensation error is formulated and a practical computation applied to the more restrictive camera case. The assessment concludes that, in the range of airborne camera utilization, the mechanical FMC technique is free of "visible" error at both human eye and computer assessment level. Lastly, the paper proceeds to a detailed technical discussion of piezoelectric drives and why they have proven to be so effective as nanopositioning devices for optical applications. The effectiveness of the patented piezoelectric drives used to achieve FMC in Optech cameras is conclusively demonstrated.

  8. Relativistic Brownian motion and the foundations of quantum mechanics

    International Nuclear Information System (INIS)

    Roy, S.

    1979-01-01

    Within the context of the generalized stochastic interpretation of quantum mechanics it is possible to deduce the quantum principles as well as to resolve the EPR paradox. Moreover, the postulates of the stochastic space-time as proposed by Frederick et al. can be deduced in a consistent way. A new possibility arises of rethinking of the existence of hidden variables in quantum mechanics

  9. Neural mechanism for sensing fast motion in dim light.

    Science.gov (United States)

    Li, Ran; Wang, Yi

    2013-11-07

    Luminance is a fundamental property of visual scenes. A population of neurons in primary visual cortex (V1) is sensitive to uniform luminance. In natural vision, however, the retinal image often changes rapidly. Consequently the luminance signals visual cells receive are transiently varying. How V1 neurons respond to such luminance changes is unknown. By applying large static uniform stimuli or grating stimuli altering at 25 Hz that resemble the rapid luminance changes in the environment, we show that approximately 40% V1 cells responded to rapid luminance changes of uniform stimuli. Most of them strongly preferred luminance decrements. Importantly, when tested with drifting gratings, the preferred speeds of these cells were significantly higher than cells responsive to static grating stimuli but not to uniform stimuli. This responsiveness can be accounted for by the preferences for low spatial frequencies and high temporal frequencies. These luminance-sensitive cells subserve the detection of fast motion under the conditions of dim illumination.

  10. Modular overconstrained weak-link mechanism for ultraprecision motion control

    International Nuclear Information System (INIS)

    Shu Deming; Toellner, Thomas S.; Alp, Esen E.

    2001-01-01

    We have designed and constructed a novel miniature overconstrained weak-link mechanism that will allow positioning of two crystals with better than 50 nrad angular resolution and nanometer linear driving sensitivity. The precision and stability of this structure allow the user to align or adjust an assembly of crystals to achieve the same performance as does a single channel-cut crystal, so we call it an ''artificial channel-cut crystal.'' Unlike the traditional kinematic linear spring mechanisms, the overconstrained weak-link mechanism provides much higher structure stiffness and stability. Using a laminar structure configured and manufactured by chemical etching and lithography techniques, we are able to design and build a planar-shape, high stiffness, high precision weak-link mechanism. In this paper, we present recent developments for the overconstrained weak-link mechanism. Applications of this new technique to synchrotron radiation instrumentation are also discussed

  11. Macroscopic theory of superconductors

    International Nuclear Information System (INIS)

    Carr, W.J. Jr.

    1981-01-01

    A macroscopic theory for bulk superconductors is developed in the framework of the theory for other magnetic materials, where ''magnetization'' current is separated from ''free'' current on the basis of scale. This contrasts with the usual separation into equilibrium and nonequilibrium currents. In the present approach magnetization, on a large macroscopic scale, results from the vortex current, while the Meissner current and other surface currents are surface contributions to the Maxwell j. The results are important for the development of thermodynamics in type-II superconductors. The advantage of the description developed here is that magnetization becomes a local concept and its associated magnetic field can be given physical meaning

  12. Proprioceptive Neuromuscular Facilitation (PNF): Its Mechanisms and Effects on Range of Motion and Muscular Function

    Science.gov (United States)

    Hindle, Kayla B.; Whitcomb, Tyler J.; Briggs, Wyatt O.; Hong, Junggi

    2012-01-01

    Proprioceptive neuromuscular facilitation (PNF) is common practice for increasing range of motion, though little research has been done to evaluate theories behind it. The purpose of this study was to review possible mechanisms, proposed theories, and physiological changes that occur due to proprioceptive neuromuscular facilitation techniques. Four theoretical mechanisms were identified: autogenic inhibition, reciprocal inhibition, stress relaxation, and the gate control theory. The studies suggest that a combination of these four mechanisms enhance range of motion. When completed prior to exercise, proprioceptive neuromuscular facilitation decreases performance in maximal effort exercises. When this stretching technique is performed consistently and post exercise, it increases athletic performance, along with range of motion. Little investigation has been done regarding the theoretical mechanisms of proprioceptive neuromuscular facilitation, though four mechanisms were identified from the literature. As stated, the main goal of proprioceptive neuromuscular facilitation is to increase range of motion and performance. Studies found both of these to be true when completed under the correct conditions. These mechanisms were found to be plausible; however, further investigation needs to be conducted. All four mechanisms behind the stretching technique explain the reasoning behind the increase in range of motion, as well as in strength and athletic performance. Proprioceptive neuromuscular facilitation shows potential benefits if performed correctly and consistently. PMID:23487249

  13. Analysis of the macroscopic mechanisms produced by rotor/stator interactions in turbomachinery; Analyse des mecanismes macroscopiques produits par les interactions rotot/stator dans les turbomachines

    Energy Technology Data Exchange (ETDEWEB)

    Callot, St.

    2002-01-15

    Unsteady phenomena produced by the relative motion between fixed and moving rows in turbomachinery is characterized by different scales in space and time. From the numerical point of view, taking into account those effects requires new models. The purpose of this work is a better understanding of the unsteady mechanisms in a multistage turbomachinery. In order to cast of any restricting hypothesis over the spatial periodicities, numerical simulations are operated over the whole circumference of each row. In the single stage case, it is shown that the unsteady flow presents a phase-lagged periodic condition which may be described by the double Fourier decomposition proposed by Tyler and Sofrin. The spatial modes precise the interaction between rows and a comparison is made with the Adamczyk's decomposition. The numerical simulation of a one and a half stage brings an extension of the analysis of the interactions in a multistage machine. (author)

  14. Relativistic Brownian motion and the foundations of quantum mechanics

    International Nuclear Information System (INIS)

    Roy, S.

    1979-01-01

    Within the context of the generalized stochastic interpretation of quantum mechanics it is possible to deduce the quantum principles as well as to resolve the EPR paradox. Moreover, the postulates of the stochastic space-time as proposed by Frederick et al. can be deduced in a consistent way. A new possibility arises of rethinking of the existence of hidden variables in quantum mechanics. (author)

  15. Macroscopic magnetic Self assembly

    NARCIS (Netherlands)

    Löthman, Per Arvid

    2018-01-01

    Exploring the macroscopic scale's similarities to the microscale is part and parcel of this thesis as reflected in the research question: what can we learn about the microscopic scale by studying the macroscale? Investigations of the environment in which the self-assembly takes place, and the

  16. The problem of the motion of bodies a historical view of the development of classical mechanics

    CERN Document Server

    Capecchi, Danilo

    2014-01-01

    This book focuses on the way in which the problem of the motion of bodies has been viewed and approached over the course of human history. It is not another traditional history of mechanics but rather aims to enable the reader to fully understand the deeper ideas that inspired men, first in attempting to understand the mechanisms of motion and then in formulating theories with predictive as well as explanatory value. Given this objective, certain parts of the history of mechanics are neglected, such as fluid mechanics, statics, and astronomy after Newton. On the other hand, due attention is paid, for example, to the history of thermodynamics, which has its own particular point of view on motion. Inspired in part by historical epistemology, the book examines the various views and theories of a given historical period (synchronic analysis) and then makes comparisons between different periods (diachronic analysis). In each period, one or two of the most meaningful contributions are selected for particular attent...

  17. Uncovering the inertia of dislocation motion and negative mechanical response in crystals.

    Science.gov (United States)

    Tang, Yizhe

    2018-01-09

    Dislocations are linear defects in crystals and their motion controls crystals' mechanical behavior. The dissipative nature of dislocation propagation is generally accepted although the specific mechanisms are still not fully understood. The inertia, which is undoubtedly the nature of motion for particles with mass, seems much less convincing for configuration propagation. We utilize atomistic simulations in conditions that minimize dissipative effects to enable uncovering of the hidden nature of dislocation motion, in three typical model metals Mg, Cu and Ta. We find that, with less/no dissipation, dislocation motion is under-damped and explicitly inertial at both low and high velocities. The inertia of dislocation motion is intrinsic, and more fundamental than the dissipative nature. The inertia originates from the kinetic energy imparted from strain energy and stored in the moving core. Peculiar negative mechanical response associated with the inertia is also discovered. These findings shed light on the fundamental nature of dislocation motion, reveal the underlying physics, and provide a new physical explanation for phenomena relevant to high-velocity dislocations.

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

    Science.gov (United States)

    Nie, Wenjie; Chen, Aixi; Lan, Yueheng

    2015-11-30

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

  19. Imaging Action Potential in Single Mammalian Neurons by Tracking the Accompanying Sub-Nanometer Mechanical Motion.

    Science.gov (United States)

    Yang, Yunze; Liu, Xian-Wei; Wang, Hui; Yu, Hui; Guan, Yan; Wang, Shaopeng; Tao, Nongjian

    2018-03-28

    Action potentials in neurons have been studied traditionally by intracellular electrophysiological recordings and more recently by the fluorescence detection methods. Here we describe a label-free optical imaging method that can measure mechanical motion in single cells with a sub-nanometer detection limit. Using the method, we have observed sub-nanometer mechanical motion accompanying the action potential in single mammalian neurons by averaging the repeated action potential spikes. The shape and width of the transient displacement are similar to those of the electrically recorded action potential, but the amplitude varies from neuron to neuron, and from one region of a neuron to another, ranging from 0.2-0.4 nm. The work indicates that action potentials may be studied noninvasively in single mammalian neurons by label-free imaging of the accompanying sub-nanometer mechanical motion.

  20. Higher order coupling between rigid-body and elastic motion in flexible mechanisms

    International Nuclear Information System (INIS)

    Esat, I.I.; Ianakiev, A.

    1995-01-01

    The paper presents an investigation of the influence of the higher order coupling terms between the rigid-body and elastic motion into flexible mechanism dynamics. The configuration of the mechanical system is obtained by using the so called hybrid coordinates. The kinematic description of the mechanism was obtained using the D-H 4 x 4 transformation matrices. The elastic deformation of each point of the mechanism is described by the finite element modeling (FEM) type interpolation scheme. The dynamic model of the flexible mechanism consists due to the hybrid coordinates of two groups of differential equations. The first group describes the manipulator transport motion and the second group describes the vibration. In this paper the authors evaluated the contribution of the coupling terms between the two groups of differential equations and selected only those with high contribution

  1. Macroscopic quantum tunnelling in a current biased Josephson junction

    International Nuclear Information System (INIS)

    Martinis, J.M.; Devoret, M.H.; Clarke, J.; Urbina, C.

    1984-11-01

    We discuss in this work an attempt to answer experimentally the question: do macroscopic variables obey quantum mechanics. More precisely, this experiment deals with the question of quantum-mechanical tunnelling of a macroscopic variable, a subject related to the famous Schrodinger's cat problem in the theory of measurement

  2. An adaptive neural mechanism for acoustic motion perception with varying sparsity

    DEFF Research Database (Denmark)

    Shaikh, Danish; Manoonpong, Poramate

    2017-01-01

    extracts directional information via a model of the peripheral auditory system of lizards. The mechanism uses only this directional information obtained via specific motor behaviour to learn the angular velocity of unoccluded sound stimuli in motion. In nature however the stimulus being tracked may...

  3. A mechanical energy harvested magnetorheological damper with linear-rotary motion converter

    Science.gov (United States)

    Chu, Ki Sum; Zou, Li; Liao, Wei-Hsin

    2016-04-01

    Magnetorheological (MR) dampers are promising to substitute traditional oil dampers because of adaptive properties of MR fluids. During vibration, significant energy is wasted due to the energy dissipation in the damper. Meanwhile, for conventional MR damping systems, extra power supply is needed. In this paper, a new energy harvester is designed in an MR damper that integrates controllable damping and energy harvesting functions into one device. The energy harvesting part of this MR damper has a unique mechanism converting linear motion to rotary motion that would be more stable and cost effective when compared to other mechanical transmissions. A Maxon motor is used as a power generator to convert the mechanical energy into electrical energy to supply power for the MR damping system. Compared to conventional approaches, there are several advantages in such an integrated device, including weight reduction, ease in installation with less maintenance. A mechanical energy harvested MR damper with linear-rotary motion converter and motion rectifier is designed, fabricated, and tested. Experimental studies on controllable damping force and harvested energy are performed with different transmissions. This energy harvesting MR damper would be suitable to vehicle suspensions, civil structures, and smart prostheses.

  4. A Novel Variable Stiffness Mechanism Capable of an Infinite Stiffness Range and Unlimited Decoupled Output Motion

    Directory of Open Access Journals (Sweden)

    Stefan Groothuis

    2014-06-01

    Full Text Available In this paper, a novel variable stiffness mechanism is presented, which is capable of achieving an output stiffness with infinite range and an unlimited output motion, i.e., the mechanism output is completely decoupled from the rotor motion, in the zero stiffness configuration. The mechanism makes use of leaf springs, which are engaged at different positions by means of two movable supports, to realize the variable output stiffness. The Euler–Bernoulli leaf spring model is derived and validated through experimental data. By shaping the leaf springs, it is shown that the stiffness characteristic of the mechanism can be changed to fulfill different application requirements. Alternative designs can achieve the same behavior with only one leaf spring and one movable support pin.

  5. Optimal design of a novel remote center-of-motion mechanism for minimally invasive surgical robot

    Science.gov (United States)

    Sun, Jingyuan; Yan, Zhiyuan; Du, Zhijiang

    2017-06-01

    Surgical robot with a remote center-of-motion (RCM) plays an important role in minimally invasive surgery (MIS) field. To make the mechanism has high flexibility and meet the demand of movements during processing of operation, an optimized RCM mechanism is proposed in this paper. Then, the kinematic performance and workspace are analyzed. Finally, a new optimization objective function is built by using the condition number index and the workspace index.

  6. Circuit Mechanisms Governing Local vs. Global Motion Processing in Mouse Visual Cortex

    DEFF Research Database (Denmark)

    Rasmussen, Rune; Yonehara, Keisuke

    2017-01-01

    components represented by component direction-selective (CDS) cells. However, how PDS and CDS cells develop their distinct response properties is still unresolved. The visual cortex of the mouse is an attractive model for experimentally solving this issue due to the large molecular and genetic toolbox...... literature on global motion processing based on works in primates and mice. Lastly, we propose what types of experiments could illuminate what circuit mechanisms are governing cortical global visual motion processing. We propose that PDS cells in mouse visual cortex appear as the perfect arena...

  7. Motion mechanics of non-adherent giant liposomes with a combined optical and atomic force microscope

    Science.gov (United States)

    Moreno-Flores, Susana; Ortíz, Rocío

    2017-11-01

    Herein we present an investigation of the motional dynamics of single mesoscopic bodies of biological relevance with an AFM-based macromanipulation tool and an optical microscope. Giant liposomes are prominent case examples as minimal cell models; studying their mechanics provides a means to address the influence of structural components in the mechanical behaviour of living cells. However, they also pose an experimental challenge due to their lightness, fragility, and high mobility. Their entrapment in wells in a fluid of lower density allows their study under conditions of constrained motion, which enables the synchronous measurement of nanoforces with motion tracking. The procedure enables to estimate sliding friction coefficients and masses of vesicles, and sheds light upon the region between the vesicle and the underlying substrate. The present study paves the way for the investigation of motion and deformation mechanics with one combined technique and a single type of experiment traditionally vetoed to objects that can move as well as deform. Such an approach can be directly applied to cells in suspension, adherent cells or cellular 3D-assemblies so as to assess substrate biocompatibility, monitor adhesion, detachment, motility as well as deformability.

  8. Motion mechanics of non-adherent giant liposomes with a combined optical and atomic force microscope

    International Nuclear Information System (INIS)

    Moreno-Flores, Susana; Ortíz, Rocío

    2017-01-01

    Herein we present an investigation of the motional dynamics of single mesoscopic bodies of biological relevance with an AFM-based macromanipulation tool and an optical microscope. Giant liposomes are prominent case examples as minimal cell models; studying their mechanics provides a means to address the influence of structural components in the mechanical behaviour of living cells. However, they also pose an experimental challenge due to their lightness, fragility, and high mobility. Their entrapment in wells in a fluid of lower density allows their study under conditions of constrained motion, which enables the synchronous measurement of nanoforces with motion tracking. The procedure enables to estimate sliding friction coefficients and masses of vesicles, and sheds light upon the region between the vesicle and the underlying substrate. The present study paves the way for the investigation of motion and deformation mechanics with one combined technique and a single type of experiment traditionally vetoed to objects that can move as well as deform. Such an approach can be directly applied to cells in suspension, adherent cells or cellular 3D-assemblies so as to assess substrate biocompatibility, monitor adhesion, detachment, motility as well as deformability. (paper)

  9. Feasibility of motion laws for planar one degree of freedom linkage mechanisms at dead point configurations

    Science.gov (United States)

    Lores García, E.; Veciana Fontanet, J. M.; Jordi Nebot, L.

    2018-01-01

    This paper proposes an analytical solution of the Inverse Kinematics (IK) problem at dead point configurations for any planar one degree of freedom linkage mechanism, with regard to the continuity Cn of the motion law. The systems analyzed are those whose elements are linked with lower pairs and do not present redundancies. The study aims to provide the user with some rules to facilitate the design of feasible motion profiles to be reproduced by conventional electrical actuators at these configurations. During the last decades, several methods and techniques have been developed to study this specific configuration. However, these techniques are mainly focused on solving numerically the IK indeterminacy, rather than analyzing the motion laws that the mechanisms are able to perform at these particular configurations. The analysis presented in this paper has been carried out differentiating and applying l'Hôpital's rule to the system of constraint equations ϕ (q) of the mechanism. The study also considers the feasibility of the time-domain profiles to be reproduced with conventional electrical actuators (i.e. AC/DC motors, linear actuators, etc.). To show the usefulness and effectiveness of the method, the development includes the analytical application and numerical simulations for two common one degree of freedom systems: a slider-crank and a four linkage mechanisms. Finally, experimental results are presented on a four linkage mechanism test bed.

  10. Macroscopic averages in Qed in material media

    International Nuclear Information System (INIS)

    Dutra, S.M.; Furuya, K.

    1997-01-01

    The starting point of macroscopic theories of quantum electrodynamics in material media is usually the classical macroscopic Maxwell equations that are then quantized. Such approach however, is based on the assumption that a macroscopic description is attainable, i.e., it assumes that we can describe the effect of the atoms of material on the field only in terms of a dielectric constant in the regime where the field has to be treated quantum mechanically. The problem we address is whether this assumption is valid at all and if so, under what conditions. We have chosen a simple model, which allows us to start from first principles and determine the validity of these approximations, without simply taking them for granted as in previous papers

  11. Nonequilibrium work relation in a macroscopic system

    International Nuclear Information System (INIS)

    Sughiyama, Yuki; Ohzeki, Masayuki

    2013-01-01

    We reconsider a well-known relationship between the fluctuation theorem and the second law of thermodynamics by evaluating stochastic evolution of the density field (probability measure valued process). In order to establish a bridge between microscopic and macroscopic behaviors, we must take the thermodynamic limit of a stochastic dynamical system following the standard procedure in statistical mechanics. The thermodynamic path characterizing a dynamical behavior in the macroscopic scale can be formulated as an infimum of the action functional for the stochastic evolution of the density field. In our formulation, the second law of thermodynamics can be derived only by symmetry of the action functional without recourse to the Jarzynski equality. Our formulation leads to a nontrivial nonequilibrium work relation for metastable (quasi-stationary) states, which are peculiar in the macroscopic system. We propose a prescription for computing the free energy for metastable states based on the resultant work relation. (paper)

  12. Nuclear physics: Macroscopic aspects

    International Nuclear Information System (INIS)

    Swiatecki, W.J.

    1993-12-01

    A systematic macroscopic, leptodermous approach to nuclear statics and dynamics is described, based formally on the assumptions ℎ → 0 and b/R << 1, where b is the surface diffuseness and R the nuclear radius. The resulting static model of shell-corrected nuclear binding energies and deformabilities is accurate to better than 1 part in a thousand and yields a firm determination of the principal properties of the nuclear fluid. As regards dynamics, the above approach suggests that nuclear shape evolutions will often be dominated by dissipation, but quantitative comparisons with experimental data are more difficult than in the case of statics. In its simplest liquid drop version the model exhibits interesting formal connections to the classic astronomical problem of rotating gravitating masses

  13. Controlled switching of single-molecule junctions by mechanical motion of a phenyl ring

    Directory of Open Access Journals (Sweden)

    Yuya Kitaguchi

    2015-10-01

    Full Text Available Mechanical methods for single-molecule control have potential for wide application in nanodevices and machines. Here we demonstrate the operation of a single-molecule switch made functional by the motion of a phenyl ring, analogous to the lever in a conventional toggle switch. The switch can be actuated by dual triggers, either by a voltage pulse or by displacement of the electrode, and electronic manipulation of the ring by chemical substitution enables rational control of the on-state conductance. Owing to its simple mechanics, structural robustness, and chemical accessibility, we propose that phenyl rings are promising components in mechanical molecular devices.

  14. Description of quantum-mechanical motion by using the formalism of non-Markov stochastic process

    International Nuclear Information System (INIS)

    Skorobogatov, G.A.; Svertilov, S.I.

    1999-01-01

    The principle possibilities of mathematical modeling of quantum mechanical motion by the theory of a real stochastic processes is considered. The set of equations corresponding to the simplest case of a two-level system undergoing transitions under the influence of electromagnetic field are obtained. It is shown that quantum-mechanical processes are purely discrete processes of non-Markovian type. They are continuous processes in the space of probability amplitudes and posses the properties of quantum Markovity. The formulation of quantum mechanics in terms of the theory of stochastic processes is necessary for its generalization on small space-time intervals [ru

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

    International Nuclear Information System (INIS)

    Sosenko, P.P.; Gresillon, D.

    1994-01-01

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

  16. Damping forces-a friend or a foe in explaining mechanical motion?

    International Nuclear Information System (INIS)

    Bartos, JirI; Musilova, Jana

    2006-01-01

    This paper presents simple, cheap, easily accessible and, for students, impressive demonstration experiments for three typical examples of physical systems for which damping forces ought to be involved in the equations of motion: a body falling in air, a damped mechanical oscillator, and Foucault currents. The various models of such forces are studied using an elementary physical and mathematical approach. It appears, maybe as a slightly surprising result, that a commonly used model of damping forces in mechanics-air drag force linearly depending on velocity-is not realistic in many typical situations. Equations of motion are solved numerically with standard software packages, even in cases where an analytical solution exists. Thus, the explanation of solved problems is on a level corresponding to an undergraduate university course in general physics. The results of these demonstration experiments are compared with the graphical outputs of numerical solutions

  17. Macroscopic nonclassical-state preparation via postselection

    Science.gov (United States)

    Montenegro, Víctor; Coto, Raúl; Eremeev, Vitalie; Orszag, Miguel

    2017-11-01

    Macroscopic quantum superposition states are fundamental to test the classical-quantum boundary and present suitable candidates for quantum technologies. Although the preparation of such states has already been realized, the existing setups commonly consider external driving and resonant interactions, predominantly by considering Jaynes-Cummings-like and beam-splitter-like interactions, as well as the nonlinear radiation pressure interaction in cavity optomechanics. In contrast to previous works on the matter, we propose a feasible probabilistic scheme to generate a macroscopic mechanical qubit, as well as phononic Schrödinger's cat states with no need of any energy exchange with the macroscopic mechanical oscillator. Essentially, we investigate an open dispersive spin-mechanical system in the absence of any external driving under nonideal conditions, such as the detrimental effects due to the oscillator and spin energy losses in a thermal bath at nonzero temperature. In our work, we show that the procedure to generate the mechanical qubit state is solely based on spin postselection in the weak to moderate coupling regime. Finally, we demonstrate that the mechanical superposition is related to the amplification of the mean values of the mechanical quadratures as they maximize the quantum coherence.

  18. Multiscale Modeling of Polycrystalline NiTi Shape Memory Alloy under Various Plastic Deformation Conditions by Coupling Microstructure Evolution and Macroscopic Mechanical Response.

    Science.gov (United States)

    Hu, Li; Jiang, Shuyong; Zhou, Tao; Tu, Jian; Shi, Laixin; Chen, Qiang; Yang, Mingbo

    2017-10-13

    Numerical modeling of microstructure evolution in various regions during uniaxial compression and canning compression of NiTi shape memory alloy (SMA) are studied through combined macroscopic and microscopic finite element simulation in order to investigate plastic deformation of NiTi SMA at 400 °C. In this approach, the macroscale material behavior is modeled with a relatively coarse finite element mesh, and then the corresponding deformation history in some selected regions in this mesh is extracted by the sub-model technique of finite element code ABAQUS and subsequently used as boundary conditions for the microscale simulation by means of crystal plasticity finite element method (CPFEM). Simulation results show that NiTi SMA exhibits an inhomogeneous plastic deformation at the microscale. Moreover, regions that suffered canning compression sustain more homogeneous plastic deformation by comparison with the corresponding regions subjected to uniaxial compression. The mitigation of inhomogeneous plastic deformation contributes to reducing the statistically stored dislocation (SSD) density in polycrystalline aggregation and also to reducing the difference of stress level in various regions of deformed NiTi SMA sample, and therefore sustaining large plastic deformation in the canning compression process.

  19. Multiscale Modeling of Polycrystalline NiTi Shape Memory Alloy under Various Plastic Deformation Conditions by Coupling Microstructure Evolution and Macroscopic Mechanical Response

    Directory of Open Access Journals (Sweden)

    Li Hu

    2017-10-01

    Full Text Available Numerical modeling of microstructure evolution in various regions during uniaxial compression and canning compression of NiTi shape memory alloy (SMA are studied through combined macroscopic and microscopic finite element simulation in order to investigate plastic deformation of NiTi SMA at 400 °C. In this approach, the macroscale material behavior is modeled with a relatively coarse finite element mesh, and then the corresponding deformation history in some selected regions in this mesh is extracted by the sub-model technique of finite element code ABAQUS and subsequently used as boundary conditions for the microscale simulation by means of crystal plasticity finite element method (CPFEM. Simulation results show that NiTi SMA exhibits an inhomogeneous plastic deformation at the microscale. Moreover, regions that suffered canning compression sustain more homogeneous plastic deformation by comparison with the corresponding regions subjected to uniaxial compression. The mitigation of inhomogeneous plastic deformation contributes to reducing the statistically stored dislocation (SSD density in polycrystalline aggregation and also to reducing the difference of stress level in various regions of deformed NiTi SMA sample, and therefore sustaining large plastic deformation in the canning compression process.

  20. Robust automated classification of first-motion polarities for focal mechanism determination with machine learning

    Science.gov (United States)

    Ross, Z. E.; Meier, M. A.; Hauksson, E.

    2017-12-01

    Accurate first-motion polarities are essential for determining earthquake focal mechanisms, but are difficult to measure automatically because of picking errors and signal to noise issues. Here we develop an algorithm for reliable automated classification of first-motion polarities using machine learning algorithms. A classifier is designed to identify whether the first-motion polarity is up, down, or undefined by examining the waveform data directly. We first improve the accuracy of automatic P-wave onset picks by maximizing a weighted signal/noise ratio for a suite of candidate picks around the automatic pick. We then use the waveform amplitudes before and after the optimized pick as features for the classification. We demonstrate the method's potential by training and testing the classifier on tens of thousands of hand-made first-motion picks by the Southern California Seismic Network. The classifier assigned the same polarity as chosen by an analyst in more than 94% of the records. We show that the method is generalizable to a variety of learning algorithms, including neural networks and random forest classifiers. The method is suitable for automated processing of large seismic waveform datasets, and can potentially be used in real-time applications, e.g. for improving the source characterizations of earthquake early warning algorithms.

  1. Circuit Mechanisms Governing Local vs. Global Motion Processing in Mouse Visual Cortex

    Directory of Open Access Journals (Sweden)

    Rune Rasmussen

    2017-12-01

    Full Text Available A withstanding question in neuroscience is how neural circuits encode representations and perceptions of the external world. A particularly well-defined visual computation is the representation of global object motion by pattern direction-selective (PDS cells from convergence of motion of local components represented by component direction-selective (CDS cells. However, how PDS and CDS cells develop their distinct response properties is still unresolved. The visual cortex of the mouse is an attractive model for experimentally solving this issue due to the large molecular and genetic toolbox available. Although mouse visual cortex lacks the highly ordered orientation columns of primates, it is organized in functional sub-networks and contains striate- and extrastriate areas like its primate counterparts. In this Perspective article, we provide an overview of the experimental and theoretical literature on global motion processing based on works in primates and mice. Lastly, we propose what types of experiments could illuminate what circuit mechanisms are governing cortical global visual motion processing. We propose that PDS cells in mouse visual cortex appear as the perfect arena for delineating and solving how individual sensory features extracted by neural circuits in peripheral brain areas are integrated to build our rich cohesive sensory experiences.

  2. Microscopic and macroscopic bell inequalities

    International Nuclear Information System (INIS)

    Santos, E.

    1984-01-01

    The Bell inequalities, being derived for micro-systems, cannot be tested by (macroscopic) experiments without additional assumptions. A macroscopic definition of local realism is proposed which might be the starting point for deriving Bell inequalities testable without auxiliary assumptions. (orig.)

  3. Mechanical Assessment of the Drip Shield Subject to Vibratory Motion and Dynamic and Static Rock Loading

    International Nuclear Information System (INIS)

    R.C. Quittmeyer

    2005-01-01

    The purpose of the drip shield (DS) is to divert water that may seep into emplacement drifts from contacting the waste packages, and to protect the waste packages from impact or static loading from rockfall. The objective of this document is to summarize, into one location, the results of a series of supporting engineering calculations that were developed to study the effect of static and dynamic loads on the mechanical performance of the DS. The potential DS loads are a result of: (1) Potential earthquake vibratory ground motion, and resulting interaction of the DS, waste package and pallet, and drift invert; (2) Dynamic impacts of rockfall resulting from emplacement drift damage as a result of earthquake vibratory motion; and (3) Static load of the caved rock rubble that may come to rest on the DS as a result of vibratory motion or from time-dependent yielding of the rock mass surrounding the emplacement drift. The potential mechanical failure mechanisms that may result from these loads include: (1) Overturning and/or separation of the interlocking DS segments; (2) Loss of structural integrity and stability of the DS, including excessive deformation or buckling; and (3) Localized damage to the top and side-wall plates of the DS. The scope of this document is limited to summarizing results presented in the supporting calculations in the areas of analysis of the potential for DS collapse, and determination of the damaged surface area of the DS plates. New calculations are presented to determine whether or not separation of DSs occur under vibratory motion

  4. Development of a mechanical model to analysis motion of standing up from the sitting position

    Directory of Open Access Journals (Sweden)

    Kasım Serbest

    2013-08-01

    Full Text Available In this study, a human body has been composed as a 6 rigid-open loop-body model which is consisted of a leg, a foot, a thigh, a trunk, an arm and a fore arm. To determine the anthropometric characteristics of the bodies has been benefited from anthropometric models and the computer software. The movements of the subject markers placed on body was viewed with a video camera in order to get location data of joints and the digitization process was made. It was computed the angular displacement, angular velocity and angular acceleration of the joints using by MATLAB (7.6.0. The obtained data was used to actuate inverse dynamics model which is created by SimMechanics (2.7.1.Motion of standing up from the sitting position was simulated by using SimMechanics software. It was compared ground reaction force calculated by SimMechanics with ground reaction force measured by force platform. This study was also shown that SimMechanics software which is developed to analyse mechanical systems in real dimensions dynamically can be used for human motion analysis. Furthermore, the simulating process has been useful to explain kinetic behaviour of the human movement.

  5. Active Polar Two-Fluid Macroscopic Dynamics

    Science.gov (United States)

    Pleiner, Harald; Svensek, Daniel; Brand, Helmut R.

    2014-03-01

    We study the dynamics of systems with a polar dynamic preferred direction. Examples include the pattern-forming growth of bacteria (in a solvent, shoals of fish (moving in water currents), flocks of birds and migrating insects (flying in windy air). Because the preferred direction only exists dynamically, but not statically, the macroscopic variable of choice is the macroscopic velocity associated with the motion of the active units. We derive the macroscopic equations for such a system and discuss novel static, reversible and irreversible cross-couplings connected to this second velocity. We find a normal mode structure quite different compared to the static descriptions, as well as linear couplings between (active) flow and e.g. densities and concentrations due to the genuine two-fluid transport derivatives. On the other hand, we get, quite similar to the static case, a direct linear relation between the stress tensor and the structure tensor. This prominent ``active'' term is responsible for many active effects, meaning that our approach can describe those effects as well. In addition, we also deal with explicitly chiral systems, which are important for many active systems. In particular, we find an active flow-induced heat current specific for the dynamic chiral polar order.

  6. Neural Mechanisms of Cortical Motion Computation Based on a Neuromorphic Sensory System

    Science.gov (United States)

    Abdul-Kreem, Luma Issa; Neumann, Heiko

    2015-01-01

    The visual cortex analyzes motion information along hierarchically arranged visual areas that interact through bidirectional interconnections. This work suggests a bio-inspired visual model focusing on the interactions of the cortical areas in which a new mechanism of feedforward and feedback processing are introduced. The model uses a neuromorphic vision sensor (silicon retina) that simulates the spike-generation functionality of the biological retina. Our model takes into account two main model visual areas, namely V1 and MT, with different feature selectivities. The initial motion is estimated in model area V1 using spatiotemporal filters to locally detect the direction of motion. Here, we adapt the filtering scheme originally suggested by Adelson and Bergen to make it consistent with the spike representation of the DVS. The responses of area V1 are weighted and pooled by area MT cells which are selective to different velocities, i.e. direction and speed. Such feature selectivity is here derived from compositions of activities in the spatio-temporal domain and integrating over larger space-time regions (receptive fields). In order to account for the bidirectional coupling of cortical areas we match properties of the feature selectivity in both areas for feedback processing. For such linkage we integrate the responses over different speeds along a particular preferred direction. Normalization of activities is carried out over the spatial as well as the feature domains to balance the activities of individual neurons in model areas V1 and MT. Our model was tested using different stimuli that moved in different directions. The results reveal that the error margin between the estimated motion and synthetic ground truth is decreased in area MT comparing with the initial estimation of area V1. In addition, the modulated V1 cell activations shows an enhancement of the initial motion estimation that is steered by feedback signals from MT cells. PMID:26554589

  7. Neural Mechanisms of Cortical Motion Computation Based on a Neuromorphic Sensory System.

    Directory of Open Access Journals (Sweden)

    Luma Issa Abdul-Kreem

    Full Text Available The visual cortex analyzes motion information along hierarchically arranged visual areas that interact through bidirectional interconnections. This work suggests a bio-inspired visual model focusing on the interactions of the cortical areas in which a new mechanism of feedforward and feedback processing are introduced. The model uses a neuromorphic vision sensor (silicon retina that simulates the spike-generation functionality of the biological retina. Our model takes into account two main model visual areas, namely V1 and MT, with different feature selectivities. The initial motion is estimated in model area V1 using spatiotemporal filters to locally detect the direction of motion. Here, we adapt the filtering scheme originally suggested by Adelson and Bergen to make it consistent with the spike representation of the DVS. The responses of area V1 are weighted and pooled by area MT cells which are selective to different velocities, i.e. direction and speed. Such feature selectivity is here derived from compositions of activities in the spatio-temporal domain and integrating over larger space-time regions (receptive fields. In order to account for the bidirectional coupling of cortical areas we match properties of the feature selectivity in both areas for feedback processing. For such linkage we integrate the responses over different speeds along a particular preferred direction. Normalization of activities is carried out over the spatial as well as the feature domains to balance the activities of individual neurons in model areas V1 and MT. Our model was tested using different stimuli that moved in different directions. The results reveal that the error margin between the estimated motion and synthetic ground truth is decreased in area MT comparing with the initial estimation of area V1. In addition, the modulated V1 cell activations shows an enhancement of the initial motion estimation that is steered by feedback signals from MT cells.

  8. Damping forces—a friend or a foe in explaining mechanical motion?

    Science.gov (United States)

    Bartos, Jirí; Musilová, Jana

    2006-03-01

    This paper presents simple, cheap, easily accessible and, for students, impressive demonstration experiments for three typical examples of physical systems for which damping forces ought to be involved in the equations of motion: a body falling in air, a damped mechanical oscillator, and Foucault currents. The various models of such forces are studied using an elementary physical and mathematical approach. It appears, maybe as a slightly surprising result, that a commonly used model of damping forces in mechanics—air drag force linearly depending on velocity—is not realistic in many typical situations. Equations of motion are solved numerically with standard software packages, even in cases where an analytical solution exists. Thus, the explanation of solved problems is on a level corresponding to an undergraduate university course in general physics. The results of these demonstration experiments are compared with the graphical outputs of numerical solutions.

  9. Glenoid labrum ossification and mechanical restriction of joint motion: extraosseous manifestations of melorheostosis

    International Nuclear Information System (INIS)

    Subhas, N.; Sundaram, M.; Recht, M.P.; Bauer, T.W.; Seitz, W.H.

    2008-01-01

    We report a case of a 47-year-old man who presented with progressive loss of motion and pain in the right shoulder. Radiographs of the shoulder demonstrated dense ossification in the glenoid and humeral head with extension into the periarticular soft tissues. CT and MRI scans confirmed the radiographic findings and also revealed ossification of the glenoid labrum. A radiographic diagnosis of melorheostosis, an uncommon benign sclerosing bone dysplasia, was made. Because of the patient's severe symptomatology, he underwent total shoulder arthroplasty. Histological analysis of the resected masses was consistent with melorheostosis with a few areas covered by a cartilage cap. This case illustrates several uncommon but important features of melorheostosis, including mechanical obstruction of joint motion requiring joint replacement, ossification of the glenoid labrum, and cartilage-covering portions of the intra-articular masses, not to be confused with cartilage-producing tumors. (orig.)

  10. Glenoid labrum ossification and mechanical restriction of joint motion: extraosseous manifestations of melorheostosis

    Energy Technology Data Exchange (ETDEWEB)

    Subhas, N.; Sundaram, M.; Recht, M.P. [Cleveland Clinic, Department of Diagnostic Radiology, Cleveland, OH (United States); Bauer, T.W. [Cleveland Clinic, Department of Anatomic Pathology, Cleveland, OH (United States); Seitz, W.H. [Cleveland Clinic, Department of Orthopaedic Surgery, Cleveland, OH (United States)

    2008-02-15

    We report a case of a 47-year-old man who presented with progressive loss of motion and pain in the right shoulder. Radiographs of the shoulder demonstrated dense ossification in the glenoid and humeral head with extension into the periarticular soft tissues. CT and MRI scans confirmed the radiographic findings and also revealed ossification of the glenoid labrum. A radiographic diagnosis of melorheostosis, an uncommon benign sclerosing bone dysplasia, was made. Because of the patient's severe symptomatology, he underwent total shoulder arthroplasty. Histological analysis of the resected masses was consistent with melorheostosis with a few areas covered by a cartilage cap. This case illustrates several uncommon but important features of melorheostosis, including mechanical obstruction of joint motion requiring joint replacement, ossification of the glenoid labrum, and cartilage-covering portions of the intra-articular masses, not to be confused with cartilage-producing tumors. (orig.)

  11. Glenoid labrum ossification and mechanical restriction of joint motion: extraosseous manifestations of melorheostosis.

    Science.gov (United States)

    Subhas, N; Sundaram, M; Bauer, T W; Seitz, W H; Recht, M P

    2008-02-01

    We report a case of a 47-year-old man who presented with progressive loss of motion and pain in the right shoulder. Radiographs of the shoulder demonstrated dense ossification in the glenoid and humeral head with extension into the periarticular soft tissues. CT and MRI scans confirmed the radiographic findings and also revealed ossification of the glenoid labrum. A radiographic diagnosis of melorheostosis, an uncommon benign sclerosing bone dysplasia, was made. Because of the patient's severe symptomatology, he underwent total shoulder arthroplasty. Histological analysis of the resected masses was consistent with melorheostosis with a few areas covered by a cartilage cap. This case illustrates several uncommon but important features of melorheostosis, including mechanical obstruction of joint motion requiring joint replacement, ossification of the glenoid labrum, and cartilage-covering portions of the intra-articular masses, not to be confused with cartilage-producing tumors.

  12. Extended Macroscopic Study of Dilute Gas Flow within a Microcavity

    Directory of Open Access Journals (Sweden)

    Mohamed Hssikou

    2016-01-01

    Full Text Available The behaviour of monatomic and dilute gas is studied in the slip and early transition regimes using the extended macroscopic theory. The gas is confined within a two-dimensional microcavity where the longitudinal sides are in the opposite motion with constant velocity ±Uw. The microcavity walls are kept at the uniform and reference temperature T0. Thus, the gas flow is transported only by the shear stress induced by the motion of upper and lower walls. From the macroscopic point of view, the regularized 13-moment equations of Grad, R13, are solved numerically. The macroscopic gas proprieties are studied for different values of the so-called Knudsen number (Kn, which gives the gas-rarefaction degree. The results are compared with those obtained using the classical continuum theory of Navier-Stokes and Fourier (NSF.

  13. Measurement-Induced Macroscopic Superposition States in Cavity Optomechanics

    DEFF Research Database (Denmark)

    Hoff, Ulrich Busk; Kollath-Bönig, Johann; Neergaard-Nielsen, Jonas Schou

    2016-01-01

    A novel protocol for generating quantum superpositions of macroscopically distinct states of a bulk mechanical oscillator is proposed, compatible with existing optomechanical devices operating in the bad-cavity limit. By combining a pulsed optomechanical quantum nondemolition (QND) interaction...

  14. Analysis of Parallelogram Mechanism used to Preserve Remote Center of Motion for Surgical Telemanipulator

    Directory of Open Access Journals (Sweden)

    Trochimczuk R.

    2017-02-01

    Full Text Available This paper presents an analysis of a parallelogram mechanism commonly used to provide a kinematic remote center of motion in surgical telemanipulators. Selected types of parallel manipulator designs, encountered in commercial and laboratory-made designs described in the medical robotics literature, will serve as the research material. Among other things, computer simulations in the ANSYS 13.0 CAD/CAE software environment, employing the finite element method, will be used. The kinematics of the solution of manipulator with the parallelogram mechanism will be determined in order to provide a more complete description. These results will form the basis for the decision regarding the possibility of applying a parallelogram mechanism in an original prototype of a telemanipulator arm.

  15. Testing quantum behaviour at the macroscopic level

    International Nuclear Information System (INIS)

    Ghirardi, G.C.

    1994-07-01

    We reconsider recent proposals to test macro realism versus quantum mechanics in experiments involving noninvasive measurement processes on a Squid. In spite of the fact that we are able to prove that the proposed experiments do not represent a test of macro realism but simply of macroscopic quantum coherence we call attention to their extreme conceptual relevance. We also discuss some recent criticisms which have been raised against the considered proposal and we show that they are not relevant. (author). 12 refs

  16. Thermomechanical macroscopic model of shape memory alloys

    International Nuclear Information System (INIS)

    Volkov, A.E.; Sakharov, V.Yu.

    2003-01-01

    The phenomenological macroscopic model of the mechanical behaviour of the titanium nickelide-type shape memory alloys is proposed. The model contains as a parameter the average phase shear deformation accompanying the martensite formation. It makes i possible to describe correctly a number of functional properties of the shape memory alloys, in particular, the pseudoelasticity ferroplasticity, plasticity transformation and shape memory effects in the stressed and unstressed samples [ru

  17. Neural mechanisms underlying sensitivity to reverse-phi motion in the fly

    Science.gov (United States)

    Meier, Matthias; Serbe, Etienne; Eichner, Hubert; Borst, Alexander

    2017-01-01

    Optical illusions provide powerful tools for mapping the algorithms and circuits that underlie visual processing, revealing structure through atypical function. Of particular note in the study of motion detection has been the reverse-phi illusion. When contrast reversals accompany discrete movement, detected direction tends to invert. This occurs across a wide range of organisms, spanning humans and invertebrates. Here, we map an algorithmic account of the phenomenon onto neural circuitry in the fruit fly Drosophila melanogaster. Through targeted silencing experiments in tethered walking flies as well as electrophysiology and calcium imaging, we demonstrate that ON- or OFF-selective local motion detector cells T4 and T5 are sensitive to certain interactions between ON and OFF. A biologically plausible detector model accounts for subtle features of this particular form of illusory motion reversal, like the re-inversion of turning responses occurring at extreme stimulus velocities. In light of comparable circuit architecture in the mammalian retina, we suggest that similar mechanisms may apply even to human psychophysics. PMID:29261684

  18. Neural mechanisms underlying sensitivity to reverse-phi motion in the fly.

    Science.gov (United States)

    Leonhardt, Aljoscha; Meier, Matthias; Serbe, Etienne; Eichner, Hubert; Borst, Alexander

    2017-01-01

    Optical illusions provide powerful tools for mapping the algorithms and circuits that underlie visual processing, revealing structure through atypical function. Of particular note in the study of motion detection has been the reverse-phi illusion. When contrast reversals accompany discrete movement, detected direction tends to invert. This occurs across a wide range of organisms, spanning humans and invertebrates. Here, we map an algorithmic account of the phenomenon onto neural circuitry in the fruit fly Drosophila melanogaster. Through targeted silencing experiments in tethered walking flies as well as electrophysiology and calcium imaging, we demonstrate that ON- or OFF-selective local motion detector cells T4 and T5 are sensitive to certain interactions between ON and OFF. A biologically plausible detector model accounts for subtle features of this particular form of illusory motion reversal, like the re-inversion of turning responses occurring at extreme stimulus velocities. In light of comparable circuit architecture in the mammalian retina, we suggest that similar mechanisms may apply even to human psychophysics.

  19. General relativistic continuum mechanics and the post-Newtonian equations of motion

    International Nuclear Information System (INIS)

    Morrill, T.H.

    1991-01-01

    Aspects are examined of general relativistic continuum mechanics. Perfectly elastic materials are dealt with but not exclusively. The derivation of their equations of motion is emphasized, in the post-Newtonian approximation. A reformulation is presented based on the tetrad formalism, of Carter and Quintana's theory of general relativistic elastic continua. A field Lagrangian is derived describing perfect material media; show that the usual covariant conservations law for perfectly elastic media is fully equivalent to the Euler-Lagrange equations describing these same media; and further show that the equations of motion for such materials follow directly from Einstein's field equations. In addition, a version of this principle shows that the local mass density in curved space-time partially depends on the amount and distribution of mass energy in the entire universe and is related to the mass density that would occur if space-time were flat. The total Lagrangian was also expanded in an EIH (Einstein, Infeld, Hoffmann) series to obtain a total post-Newtonian Lagrangian. The results agree with those found by solving Einstein's equations for the metric coefficients and by deriving the post-Newtonian equations of motion from the covariant conservation law

  20. Tubular microjets: Fabrication, factors affecting the motion and mechanism of propulsion

    Science.gov (United States)

    Parmar, Jemish; Vilela, Diana; Sanchez, Samuel

    2016-11-01

    Artificial micro- and nano-swimmers are interesting systems for both fundamental understandings of swimming at low Reynolds numbers and for their promising applications in many fields, such as environmental and biomedical fields. Different architectures of self-propelled systems present various propulsion mechanisms. Among them, tubular microjets are widely used for different applications. Here, we briefly describe the fabrication of microjets by rolling up thin film and electrodeposition techniques and the principles behind these processes. Different parameters affecting the motion of microjets and existing theoretical models about microjet propulsion are discussed.

  1. Anderson phase-slip theory and loss mechanism of the motion of vortices in superconductors

    International Nuclear Information System (INIS)

    Xu, L.K.; Shan, L.; Tang, Y.L.; Wang, F.; Xu, X.N.; Jin, X.; Nanjing Univ.

    2001-01-01

    The loss mechanism of the super-current is discussed in the frame of Anderson phase-slip theory and G-L theory. In the discussion we also use vortex conservation equations instead of Maxwell equations. It is found that this method is more reasonable to apply the vortex motion induced energy loss in type II superconductors than the traditional deduction in terms of Maxwell equations. Moreover, we propose a new method to determine the effective pinning energy of vortex lines in type II superconductors. (orig.)

  2. Towards routine determination of focal mechanisms obtained from first motion P-wave arrivals

    Science.gov (United States)

    Lentas, K.

    2018-03-01

    The Bulletin of the International Seismological Centre (ISC) contains information on earthquake mechanisms collected from many different sources including national and global agencies, resulting in a satisfactory coverage over a wide magnitude range (M ˜2-9). Nevertheless, there are still a vast number of earthquakes with no reported source mechanisms especially for magnitudes up to 5. This study investigates the possibility of calculating earthquake focal mechanisms in a routine and systematic way based on P-wave first motion polarities. Any available parametric data in the ISC database is being used, as well as auto-picked polarities from waveform data up to teleseismic epicentral distances (90°) for stations that are not reported to the ISC. The determination of the earthquake mechanisms is carried out with a modified version of the HASH algorithm that is compatible with a wide range of epicentral distances and takes into account the ellipsoids defined by the ISC location errors, and the Earth's structure uncertainties. Initially, benchmark tests for a set of ISC reviewed earthquakes (mb > 4.5) are carried out and the HASH mechanism classification scheme is used to define the mechanism quality. Focal mechanisms of quality A, B and C with an azimuthal gap up to 90° compare well to the benchmark mechanisms. Nevertheless, the majority of the obtained mechanisms fall into class D as a result of limited polarity data from stations in local/regional epicentral distances. Specifically, the computation of the minimum rotation angle between the obtained mechanisms and the benchmarks, reveals that 41 per cent of the examined earthquakes show rotation angles up to 35°. Finally, the current technique is applied to a small set of earthquakes from the reviewed ISC bulletin where 62 earthquakes, with no previously reported source mechanisms, are successfully obtained.

  3. Macroscopic constraints on string unification

    International Nuclear Information System (INIS)

    Taylor, T.R.

    1989-03-01

    The comparison of sting theory with experiment requires a huge extrapolation from the microscopic distances, of order of the Planck length, up to the macroscopic laboratory distances. The quantum effects give rise to large corrections to the macroscopic predictions of sting unification. I discus the model-independent constraints on the gravitational sector of string theory due to the inevitable existence of universal Fradkin-Tseytlin dilatons. 9 refs

  4. One-dimensional phased array with mechanical motion for conformal ultrasound hyperthermia

    International Nuclear Information System (INIS)

    Ju, Kuen-Cheng; Chen, Yung-Yaw; Lin, Win-Li; Kuo, Te-Son

    2003-01-01

    This paper investigates the feasibility of conformal heating for external ultrasound hyperthermia by using a phased array transducer with mechanical motion. In this system, a one-dimensional phased array is arranged on a shaft and moves along the shaft, while dynamically focusing on the planning target volume (PTV) with numerous focal spots. To prevent overheating in the intervening tissue between the skin and the PTV, the shaft and the phased array are rotated together to enlarge the acoustical window. With the purpose of conformal heating, the power deposition of the PTV is constructed by combinations of the focal spots and an iterative gradient descent method is then used to determine an optimal set of power weightings for the focal spots. Different tumour shapes are evaluated and the simulation results demonstrate that the volume percentage of the PTV with temperatures higher than 43 deg. C is over 95%. The overheating volume outside the PTV is less than 25% of the PTV. This method provides good conformal heating for external ultrasound hyperthermia. The concept of combining electrical focusing and mechanical motion has the advantages of both enlarging the acoustic window and providing dynamic focusing ability, which is essential for successful conformal heating

  5. A Method for Mechanism Analysis of Frog Swimming Based on Motion Observation Experiments

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2014-05-01

    Full Text Available For understanding the mechanism of frog swimming under water and designing a frog-inspired swimming robot, kinematics of the frog body and trajectories of joints should be obtained. In this paper, an aquatic frog, Xenopus laevis, was chosen for analysis of swimming motions which were recorded by a high speed camera, and kinematic data were processed in a swimming data extraction platform. According to the shape features of the frog, we propose a method that the frog eyes are set as the natural data extraction markers for body motion, and kinematic data of joint trajectories are calculated by the contour points on the limbs. For the data processing, a pinhole camera model was built to transform the pixel coordinate system to world coordinate system, and the errors caused by the water refraction were analyzed and corrected. Finally, from the developed data extraction platform, the kinematic data for the analysis of swimming mechanism and design of frog-inspired robot were obtained.

  6. The mechanism of upper-oceanic vertical motions forced by a moving typhoon

    International Nuclear Information System (INIS)

    Suzuki, Shin-ichi; Niino, Hiroshi; Kimura, Ryuji

    2011-01-01

    The upper-oceanic response to a moving typhoon, and the mechanism of the response, are studied based on linear theory and a numerical experiment. The results of the analysis by linear theory are summarized as follows. Three different processes (Ekman pumping, inertial pumping and 'anti-Ekman' pumping) contribute to the upper-oceanic vertical motions caused by a moving atmospheric disturbance. The dominant process depends on the Coriolis parameter f, the moving speed U of the disturbance and the along-track wavenumber spectrum of the wind stress curl. In the case of a typhoon, when the wavenumber spectrum has a dominant amplitude at k< f/U, Ekman pumping is the dominant mechanism and upwelling occurs at the typhoon center, where k is the along-track wavenumber. When the wavenumber spectrum has a significant amplitude near k∼f/U, inertial pumping is dominant and upwelling occurs to the rear of the typhoon center. The results of the numerical experiments show that linear theory performs well in explaining the horizontal structures of the upper-oceanic vertical motions and their dependence on the moving speed of the typhoon.

  7. Source mechanism inversion and ground motion modeling of induced earthquakes in Kuwait - A Bayesian approach

    Science.gov (United States)

    Gu, C.; Toksoz, M. N.; Marzouk, Y.; Al-Enezi, A.; Al-Jeri, F.; Buyukozturk, O.

    2016-12-01

    The increasing seismic activity in the regions of oil/gas fields due to fluid injection/extraction and hydraulic fracturing has drawn new attention in both academia and industry. Source mechanism and triggering stress of these induced earthquakes are of great importance for understanding the physics of the seismic processes in reservoirs, and predicting ground motion in the vicinity of oil/gas fields. The induced seismicity data in our study are from Kuwait National Seismic Network (KNSN). Historically, Kuwait has low local seismicity; however, in recent years the KNSN has monitored more and more local earthquakes. Since 1997, the KNSN has recorded more than 1000 earthquakes (Mw Institutions for Seismology (IRIS) and KNSN, and widely felt by people in Kuwait. These earthquakes happen repeatedly in the same locations close to the oil/gas fields in Kuwait (see the uploaded image). The earthquakes are generally small (Mw stress of these earthquakes was calculated based on the source mechanisms results. In addition, we modeled the ground motion in Kuwait due to these local earthquakes. Our results show that most likely these local earthquakes occurred on pre-existing faults and were triggered by oil field activities. These events are generally smaller than Mw 5; however, these events, occurring in the reservoirs, are very shallow with focal depths less than about 4 km. As a result, in Kuwait, where oil fields are close to populated areas, these induced earthquakes could produce ground accelerations high enough to cause damage to local structures without using seismic design criteria.

  8. Development of a body motion interactive system with a weight voting mechanism and computer vision technology

    Science.gov (United States)

    Lin, Chern-Sheng; Chen, Chia-Tse; Shei, Hung-Jung; Lay, Yun-Long; Chiu, Chuang-Chien

    2012-09-01

    This study develops a body motion interactive system with computer vision technology. This application combines interactive games, art performing, and exercise training system. Multiple image processing and computer vision technologies are used in this study. The system can calculate the characteristics of an object color, and then perform color segmentation. When there is a wrong action judgment, the system will avoid the error with a weight voting mechanism, which can set the condition score and weight value for the action judgment, and choose the best action judgment from the weight voting mechanism. Finally, this study estimated the reliability of the system in order to make improvements. The results showed that, this method has good effect on accuracy and stability during operations of the human-machine interface of the sports training system.

  9. Invasion from a cell aggregate—the roles of active cell motion and mechanical equilibrium

    International Nuclear Information System (INIS)

    Szabó, A; Varga, K; Czirók, A; Garay, T; Hegedűs, B

    2012-01-01

    Cell invasion from an aggregate into a surrounding extracellular matrix (ECM) is an important process during development disease, e.g., vascular network assembly or tumor progression. To describe the behavior emerging from autonomous cell motility, cell–cell adhesion and contact guidance by ECM filaments, we propose a suitably modified cellular Potts model. We consider an active cell motility process in which internal polarity is governed by a positive feedback from cell displacements, a mechanism that can result in highly persistent motion when constrained by an oriented ECM structure. The model allows us to explore the interplay between haptotaxis, matrix degradation and active cell movement. We show that for certain conditions the cells are able to both invade the ECM and follow the ECM tracks. Furthermore, we argue that enforcing mechanical equilibrium within a bulk cell mass is of key importance in multicellular simulations

  10. Increased multiaxial lumbar motion responses during multiple-impulse mechanical force manually assisted spinal manipulation

    Directory of Open Access Journals (Sweden)

    Gunzburg Robert

    2006-04-01

    Full Text Available Abstract Background Spinal manipulation has been found to create demonstrable segmental and intersegmental spinal motions thought to be biomechanically related to its mechanisms. In the case of impulsive-type instrument device comparisons, significant differences in the force-time characteristics and concomitant motion responses of spinal manipulative instruments have been reported, but studies investigating the response to multiple thrusts (multiple impulse trains have not been conducted. The purpose of this study was to determine multi-axial segmental and intersegmental motion responses of ovine lumbar vertebrae to single impulse and multiple impulse spinal manipulative thrusts (SMTs. Methods Fifteen adolescent Merino sheep were examined. Tri-axial accelerometers were attached to intraosseous pins rigidly fixed to the L1 and L2 lumbar spinous processes under fluoroscopic guidance while the animals were anesthetized. A hand-held electromechanical chiropractic adjusting instrument (Impulse was used to apply single and repeated force impulses (13 total over a 2.5 second time interval at three different force settings (low, medium, and high along the posteroanterior axis of the T12 spinous process. Axial (AX, posteroanterior (PA, and medial-lateral (ML acceleration responses in adjacent segments (L1, L2 were recorded at a rate of 5000 samples per second. Peak-peak segmental accelerations (L1, L2 and intersegmental acceleration transfer (L1–L2 for each axis and each force setting were computed from the acceleration-time recordings. The initial acceleration response for a single thrust and the maximum acceleration response observed during the 12 multiple impulse trains were compared using a paired observations t-test (POTT, alpha = .05. Results Segmental and intersegmental acceleration responses mirrored the peak force magnitude produced by the Impulse Adjusting Instrument. Accelerations were greatest for AX and PA measurement axes. Compared to

  11. Energy-imbalance mechanism of domain wall motion induced by propagation spin waves in finite magnetic nanostripe

    International Nuclear Information System (INIS)

    Zhu, Jinrong; Han, Zhaoyan; Su, Yuanchang; Hu, Jingguo

    2014-01-01

    The mechanism of the domain wall (DW) motions induced by spin wave in finite magnetic nanostripe is studied by micromagnetic simulations. We find that the spin-wave induced DM motions are always accompanied by an energy imbalance between two sides of the DW. The DW motion can be attributed to the expansion of the low-energy-density area and the contraction of the high-energy-density area. The energy imbalance strongly depends on whether the spin wave passes through the DW or is reflected by the DW. In the area of the spin wave propagation, the energy density increases with the time. However, in the superposition area of the incident spin wave and the reflected spin wave, the energy density decreases with the increasing of the time. It shows that this energy imbalance can be controlled by tuning the frequency of the spin wave. Finally, the effect of the damping parameter value is discussed. - Highlights: • The mechanism of the spin-wave induced DW motions is studied. • The spin-wave induced DW motions and the energy imbalance mechanism are given. • The DW motion with the same direction to that of SW is explained. • The DW motion with the opposite direction to that of SW is explained

  12. Coupled rolling motion: a student project in non-holonomic mechanics

    International Nuclear Information System (INIS)

    Janova, Jitka; Musilova, Jana; Bartos, JirI

    2009-01-01

    This paper presents an original undergraduate student project in theoretical mechanics: a demonstration of theory and experiment agreement inspired by a recently theoretically treated mechanical problem of coupled rolling motion of two cylinders. The problem of a mechanical system subjected to non-holonomic constraints is theoretically and numerically solved. Subsequently, the solution is quantitatively verified by a simple and inexpensive experiment, originally proposed and constructed by the authors. The comparison of results of the theoretical study with experimental output shows that there are instruments to directly verify rather abstract mathematical theories even on the undergraduate level. Moreover, combining the theoretical description of the problem with an appropriate laboratory experiment and computational procedures gives students a more complex view of the physical problem as a whole. This paper can be used by physics teachers on the undergraduate university level as an inspiration for an interesting student project. Moreover, the theoretical part of this paper itself can be used by interested intermediate students themselves as a good exercise in theoretical mechanics.

  13. A macroscopic constitutive model of temperature-induced phase transition of polycrystalline Ni2MnGa by directional solidification

    International Nuclear Information System (INIS)

    Zhu, Yuping; Gu, Yunling; Liu, Hongguang

    2015-01-01

    Directional solidification technology has been widely used to improve the properties of polycrystalline Ni 2 MnGa materials. Mechanical training can adjust the internal organizational structures of the materials, reduce the stress of twin boundaries motion, and then result in larger strain at lower outfield levels. In this paper, we test the microscopic structure of Ni 2 MnGa polycrystalline ferromagnetic shape memory alloy produced by directional solidification and compress it along two axes successively for mechanical training. The influences of pre-compressive stresses on the temperature-induced strains are analyzed. The macroscopic mechanical behaviors show anisotropy. According to the generating mechanism of the macroscopic strain, a three-dimensional constitutive model is established. Based on thermodynamic method, the kinetic equations of the martensitic transformation and inverse transformation are presented considering the driving force and energy dissipation. The prediction curves of temperature-induce strains along two different directions are investigated. And the results coincide well with the experiment data. It well explains the macroscopic anisotropy mechanical behaviors and fits for using in engineering

  14. Highly porous layers of silica nanospheres sintered by drying: scaling up of the elastic properties of the beads to the macroscopic mechanical properties.

    Science.gov (United States)

    Lesaine, Arnaud; Bonamy, Daniel; Gauthier, Georges; Rountree, Cindy L; Lazarus, Véronique

    2018-05-16

    Layers obtained by drying a colloidal dispersion of silica spheres are found to be a good benchmark to test the elastic behaviour of porous media, in the challenging case of high porosities and nano-sized microstructures. Classically used for these systems, Kendall's approach explicitly considers the effect of surface adhesive forces onto the contact area between the particles. This approach provides the Young's modulus using a single adjustable parameter (the adhesion energy) but provides no further information on the tensorial nature and possible anisotropy of elasticity. On the other hand, homogenization approaches (e.g. rule of mixtures, and Eshelby, Mori-Tanaka and self-consistent schemes), based on continuum mechanics and asymptotic analysis, provide the stiffness tensor from the knowledge of the porosity and the elastic constants of the beads. Herein, the self-consistent scheme accurately predicts both bulk and shear moduli, with no adjustable parameter, provided the porosity is less than 35%, for layers composed of particles as small as 15 nm in diameter. Conversely, Kendall's approach is found to predict the Young's modulus over the full porosity range. Moreover, the adhesion energy in Kendall's model has to be adjusted to a value of the order of the fracture energy of the particle material. This suggests that sintering during drying leads to the formation of covalent siloxane bonds between the particles.

  15. Quasi-static and dynamic compressive deformation of a bulk nanolayered Ag–Cu eutectic alloy: Macroscopic response and dominant deformation mechanisms

    International Nuclear Information System (INIS)

    Kingstedt, O.T.; Eftink, B.; Lambros, J.; Robertson, I.M.

    2014-01-01

    Nanostructured multilayered material systems offer an attractive method of increasing material strength. This work examines the response of a bulk eutectic silver–copper material (Ag 60 Cu 40 , subscripts indicating atomic percent) which has a hierarchical structure of alternating Ag and Cu layers with thicknesses down to 50 nm. The hierarchical structure consists of two primary arrangements of layers, eutectic colonies of parallel layers, most commonly found at the material interior, and “grains” consisting of alternating Ag and Cu layers which emanate from a central region in a radial pattern, most commonly found at the material exterior surface. We show that the hierarchical structure causes a significant increase in the measured strength response when comparing the Ag 60 Cu 40 response to that of the constituent materials in their bulk nanograined or micrograined form. The deformation mechanisms of this material are studied under compressive loading over the quasi-static and dynamic regime (10 −3 –10 3 s −1 ) with strain between 5% and 50%

  16. Potential of mechanical metamaterials to induce their own global rotational motion

    Science.gov (United States)

    Dudek, K. K.; Wojciechowski, K. W.; Dudek, M. R.; Gatt, R.; Mizzi, L.; Grima, J. N.

    2018-05-01

    The potential of several classes of mechanical metamaterials to induce their own overall rotational motion through the individual rotation of their subunits is examined. Using a theoretical approach, we confirm that for various rotating rigid unit systems, if by design the sum of angular momentum of subunits rotating in different directions is made to be unequal, then the system will experience an overall rotation, the extent of which may be controlled through careful choice of the geometric parameters defining these systems. This phenomenon of self-induced rotation is also confirmed experimentally. Furthermore, we discuss how these systems can be designed in a special way so as to permit extended rotations which allows them to overcome geometric lockage and the relevance of this concept in applications ranging from satellites to spacecraft and telescopes employed in space.

  17. Aerodynamics power consumption for mechanical flapping wings undergoing flapping and pitching motion

    Science.gov (United States)

    Razak, N. A.; Dimitriadis, G.; Razaami, A. F.

    2017-07-01

    Lately, due to the growing interest in Micro Aerial Vehicles (MAV), interest in flapping flight has been rekindled. The reason lies in the improved performance of flapping wing flight at low Reynolds number regime. Many studies involving flapping wing flight focused on the generation of unsteady aerodynamic forces such as lift and thrust. There is one aspect of flapping wing flight that received less attention. The aspect is aerodynamic power consumption. Since most mechanical flapping wing aircraft ever designed are battery powered, power consumption is fundamental in improving flight endurance. This paper reports the results of experiments carried out on mechanical wings under going active root flapping and pitching in the wind tunnel. The objective of the work is to investigate the effect of the pitch angle oscillations and wing profile on the power consumption of flapping wings via generation of unsteady aerodynamic forces. The experiments were repeated for different airspeeds, flapping and pitching kinematics, geometric angle of attack and wing sections with symmetric and cambered airfoils. A specially designed mechanical flapper modelled on large migrating birds was used. It will be shown that, under pitch leading conditions, less power is required to overcome the unsteady aerodnamics forces. The study finds less power requirement for downstroke compared to upstroke motion. Overall results demonstrate power consumption depends directly on the unsteady lift force.

  18. Micro- and macroscopic photonic control of matter

    Science.gov (United States)

    Ryabtsev, Anton

    parameters. In order for measurements not to be skewed, these interactions need to be taken into account and mitigated at the time of the experiment or handled later in data analysis and simulations. Experimental results are presented in four chapters. Chapter 2 describes two topics: (1) single-shot real-time monitoring and correction of spectral phase drifts, which commonly originate from temperature and pointing fluctuations inside the laser cavity when the pulses are generated; (2) an all-optical method for controlling the dispersion of femtosecond pulses using other pulses. Chapter 3 focuses on the effects of the propagation media--how intense laser pulses modify media and how, in turn, the media modifies them back--and how these effects can be counteracted. Self-action effects in fused silica are discussed, along with some interesting and unexpected results. A method is then proposed for mitigating self-action processes using binary modulation of the spectral phases of laser pulses. Chapter 4 outlines the design of two laser systems, which are specifically tailored for particular spectroscopic applications and incorporate the comprehensive pulse control described in previous chapters. Chapter 5 shows how control of spatial beam characteristics can be applied to measurements of the mechanical motion of microscale particles and how it can potentially be applied to molecular motion. It also describes an experiment on laser-induced flow in air in which attempts were made to control the macroscopic molecular rotation of gases. My research, with a pulse shaper as the enabling tool, provides important insights into ultrafast scientific studies by making femtosecond laser research more predictable, reliable and practical for measurement and control. In the long term, some of the research methods in this thesis may help the transition of femtosecond lasers from the laboratory environment into clinics, factories, airports, and other everyday settings.

  19. Macroscopic models for traffic safety.

    NARCIS (Netherlands)

    Oppe, S.

    1988-01-01

    Recently there has been an increased interest in the application of macroscopic models for the description of developments in traffic safety. A discussion was started on the causes of the sudden decrease in the number of fatal and injury accidents after 1974. Before that time these numbers had

  20. The macroscopic harmonic oscillator and quantum measurements

    International Nuclear Information System (INIS)

    Hayward, R.W.

    1982-01-01

    A quantum mechanical description of a one-dimensional macroscopic harmonic oscillator interacting with its environment is given. Quasi-coherent states are introduced to serve as convenient basis states for application of a density matrix formalism to characterize the system. Attention is given to the pertinent quantum limits to the precision of measurement of physical observables that may provide some information on the nature of a weak classical force interacting with the oscillator. A number of ''quantum nondemolition'' schemes proposed by various authors are discussed. (Auth.)

  1. Evaluation of the added mass for a spheroid-type unmanned underwater vehicle by vertical planar motion mechanism test

    Directory of Open Access Journals (Sweden)

    Seong-Keon Lee

    2011-09-01

    Full Text Available This paper shows added mass and inertia can be acquired from the pure heaving motion and pure pitching motion respectively. A Vertical Planar Motion Mechanism (VPMM test for the spheroid-type Unmanned Underwater Vehicle (UUV was compared with a theoretical calculation and Computational Fluid Dynamics (CFD analysis in this paper. The VPMM test has been carried out at a towing tank with specially manufactured equipment. The linear equations of motion on the vertical plane were considered for theoretical calculation, and CFD results were obtained by commercial CFD package. The VPMM test results show good agreement with theoretical calculations and the CFD results, so that the applicability of the VPMM equipment for an underwater vehicle can be verified with a sufficient accuracy.

  2. The effect of unilateral arm swing motion on lower extremity running mechanics associated with injury risk.

    Science.gov (United States)

    Agresta, Cristine; Ward, Christian R; Wright, W Geoffrey; Tucker, Carole A

    2018-06-01

    Many field sports involve equipment that restricts one or both arms from moving while running. Arm swing during running has been examined from a biomechanical and physiologic perspective but not from an injury perspective. Moreover, only bilateral arm swing suppression has been studied with respect to running. The purpose of this study was to determine the influence of running with one arm restrained on lower extremity mechanics associated with running or sport-related injury. Fifteen healthy participants ran at a self-selected speed with typical arm swing, with one arm restrained and with both arms restrained. Lower extremity kinematics and spatiotemporal measures were analysed for all arm swing conditions. Running with one arm restrained resulted in increased frontal plane knee and hip angles, decreased foot strike angle, and decreased centre of mass vertical displacement compared to typical arm swing or bilateral arm swing restriction. Stride length was decreased and step frequency increased when running with one or both arms restrained. Unilateral arm swing restriction induces changes in lower extremity kinematics that are not similar to running with bilateral arm swing restriction or typical arm swing motion. Running with one arm restrained increases frontal plane mechanics associated with risk of knee injury.

  3. Brownian motion or Lévy walk? Stepping towards an extended statistical mechanics for animal locomotion.

    Science.gov (United States)

    Gautestad, Arild O

    2012-09-07

    Animals moving under the influence of spatio-temporal scaling and long-term memory generate a kind of space-use pattern that has proved difficult to model within a coherent theoretical framework. An extended kind of statistical mechanics is needed, accounting for both the effects of spatial memory and scale-free space use, and put into a context of ecological conditions. Simulations illustrating the distinction between scale-specific and scale-free locomotion are presented. The results show how observational scale (time lag between relocations of an individual) may critically influence the interpretation of the underlying process. In this respect, a novel protocol is proposed as a method to distinguish between some main movement classes. For example, the 'power law in disguise' paradox-from a composite Brownian motion consisting of a superposition of independent movement processes at different scales-may be resolved by shifting the focus from pattern analysis at one particular temporal resolution towards a more process-oriented approach involving several scales of observation. A more explicit consideration of system complexity within a statistical mechanical framework, supplementing the more traditional mechanistic modelling approach, is advocated.

  4. Your body mechanics in motion : proactive training for stepping, handling, lifting

    Energy Technology Data Exchange (ETDEWEB)

    Hanchara, L.; Strong, J. [Kinetic Safety Consulting Inc., Grande Prairie, AB (Canada)

    2007-07-01

    Over a third of all injuries in the oil and gas industry are caused by strains. Nearly 50 per cent of back injuries in the industry are reported by workers on the job for less than 6 months. This presentation provided details of Mechanics in Motion, a program designed to promote proactive and safe conditions for workers in the petroleum industry. The program presented methods of improving posture when lifting, stepping, reaching, and carrying. The program was created in 2005 in order to serve as a preventative tool in the oilfield. Outlines of body fulcrums and levers were presented, as well as the types of joints that are most prone to workplace injuries. Field and office ergonomics were reviewed, and various correct lifting techniques were presented. Worksite warm-up programs were provided, as well as a set of stretches designed specifically for the back. It was concluded that understanding oilfield ergonomics and the mechanical principles of the body may help to prevent injuries in the workplace. tabs., figs.

  5. Pathways toward understanding Macroscopic Quantum Phenomena

    International Nuclear Information System (INIS)

    Hu, B L; Subaşi, Y

    2013-01-01

    Macroscopic quantum phenomena refer to quantum features in objects of 'large' sizes, systems with many components or degrees of freedom, organized in some ways where they can be identified as macroscopic objects. This emerging field is ushered in by several categories of definitive experiments in superconductivity, electromechanical systems, Bose-Einstein condensates and others. Yet this new field which is rich in open issues at the foundation of quantum and statistical physics remains little explored theoretically (with the important exception of the work of A J Leggett [1], while touched upon or implied by several groups of authors represented in this conference. Our attitude differs in that we believe in the full validity of quantum mechanics stretching from the testable micro to meso scales, with no need for the introduction of new laws of physics.) This talk summarizes our thoughts in attempting a systematic investigation into some key foundational issues of quantum macroscopic phenomena, with the goal of ultimately revealing or building a viable theoretical framework. Three major themes discussed in three intended essays are the large N expansion [2], the correlation hierarchy [3] and quantum entanglement [4]. We give a sketch of the first two themes and then discuss several key issues in the consideration of macro and quantum, namely, a) recognition that there exist many levels of structure in a composite body and only by judicious choice of an appropriate set of collective variables can one give the best description of the dynamics of a specific level of structure. Capturing the quantum features of a macroscopic object is greatly facilitated by the existence and functioning of these collective variables; b) quantum entanglement, an exclusively quantum feature [5], is known to persist to high temperatures [6] and large scales [7] under certain conditions, and may actually decrease with increased connectivity in a quantum network [8]. We use entanglement as a

  6. Optimization of voltage output of energy harvesters with continuous mechanical rotation extracted from human motion (Conference Presentation)

    Science.gov (United States)

    Rashid, Evan; Hamidi, Armita; Tadesse, Yonas

    2017-04-01

    With increasing popularity of portable devices for outdoor activities, portable energy harvesting devices are coming into spot light. The next generation energy harvester which is called hybrid energy harvester can employ more than one mechanism in a single device to optimize portion of the energy that can be harvested from any source of waste energy namely motion, vibration, heat and etc. In spite of few recent attempts for creating hybrid portable devices, the level of output energy still needs to be improved with the intention of employing them in commercial electronic systems or further applications. Moreover, implementing a practical hybrid energy harvester in different application for further investigation is still challenging. This proposal is projected to incorporate a novel approach to maximize and optimize the voltage output of hybrid energy harvesters to achieve a greater conversion efficiency normalized by the total mass of the hybrid device than the simple arithmetic sum of the individual harvesting mechanisms. The energy harvester model previously proposed by Larkin and Tadesse [1] is used as a baseline and a continuous unidirectional rotation is incorporated to maximize and optimize the output. The device harvest mechanical energy from oscillatory motion and convert it to electrical energy through electromagnetic and piezoelectric systems. The new designed mechanism upgrades the device in a way that can harvest energy from both rotational and linear motions by using magnets. Likewise, the piezoelectric section optimized to harvest at least 10% more energy. To the end, the device scaled down for tested with different sources of vibrations in the immediate environment, including machinery operation, bicycle, door motion while opening and closing and finally, human motions. Comparing the results from literature proved that current device has capability to be employed in commercial small electronic devices for enhancement of battery usage or as a backup

  7. Patient-Centered Robot-Aided Passive Neurorehabilitation Exercise Based on Safety-Motion Decision-Making Mechanism

    Directory of Open Access Journals (Sweden)

    Lizheng Pan

    2017-01-01

    Full Text Available Safety is one of the crucial issues for robot-aided neurorehabilitation exercise. When it comes to the passive rehabilitation training for stroke patients, the existing control strategies are usually just based on position control to carry out the training, and the patient is out of the controller. However, to some extent, the patient should be taken as a “cooperator” of the training activity, and the movement speed and range of the training movement should be dynamically regulated according to the internal or external state of the subject, just as what the therapist does in clinical therapy. This research presents a novel motion control strategy for patient-centered robot-aided passive neurorehabilitation exercise from the point of the safety. The safety-motion decision-making mechanism is developed to online observe and assess the physical state of training impaired-limb and motion performances and regulate the training parameters (motion speed and training rage, ensuring the safety of the supplied rehabilitation exercise. Meanwhile, position-based impedance control is employed to realize the trajectory tracking motion with interactive compliance. Functional experiments and clinical experiments are investigated with a healthy adult and four recruited stroke patients, respectively. The two types of experimental results demonstrate that the suggested control strategy not only serves with safety-motion training but also presents rehabilitation efficacy.

  8. Component Energy Efficiencies in a Novel Linear to Rotary Motion Inter-conversion Hydro-mechanism Running a Solar Tracker

    Directory of Open Access Journals (Sweden)

    Kant Eliab Kanyarusoke

    2018-01-01

    Full Text Available A new mechanism interconverting linear and rotary motion was investigated for energy transfers among its components. It employed a gear-rack set, a Hooke coupling and a specially designed bladder-valve system that regulated the motion. The purpose was to estimate individual component mechanical efficiencies as they existed in the prototype so that future reengineering of the mechanism could be properly targeted. Theoretical modelling of the mechanism was first done to obtain equations for efficiencies of the key components. Two-stage experimentation followed when running a solar tracker. The first stage produced data for inputting into the model to determine the efficiencies’ theoretical variation with the Hooke coupling shaft angle. The second one verified results of the Engineering Equation Solver (EES software solutions of the model. It was found that the energy transfer to focus on was that between the Hooke coupling and the output shaft because its efficiency was below 4%

  9. Macroscopic description of isoscalar giant multipole resonances

    International Nuclear Information System (INIS)

    Nix, J.R.; Sierk, A.J.

    1980-01-01

    On the basis of a simple macroscopic model, we calculate the isoscalar giant-resonance energy as a function of mass number and multipole degree. The restoring force is determined from the distortion of the Fermi surface, and the inertia is determined for the incompressible, irrotational flow of nucleons with unit effective mass. With no adjustable parameters, the resulting closed expression reproduces correctly the available experimental data, namely the magnitude and dependence upon mass number of the giant quadrupole energy and the magnitude of the giant octupole energy for 208 Pb. We also calculate the isoscalar giant-resonance width as a function of mass number and multipole degree for various macroscopic damping mechanisms, including two-body viscosity, one-body dissipation, and modified one-body dissipation. None of these damping mechanisms reproduces correctly all features of the available experimental data, namely the magnitude and dependence upon mass number of the giant quadrupole width and the magnitude of the giant octupole width for 208 Pb

  10. Comparable mechanisms of working memory interference by auditory and visual motion in youth and aging.

    Science.gov (United States)

    Mishra, Jyoti; Zanto, Theodore; Nilakantan, Aneesha; Gazzaley, Adam

    2013-08-01

    Intrasensory interference during visual working memory (WM) maintenance by object stimuli (such as faces and scenes), has been shown to negatively impact WM performance, with greater detrimental impacts of interference observed in aging. Here we assessed age-related impacts by intrasensory WM interference from lower-level stimulus features such as visual and auditory motion stimuli. We consistently found that interference in the form of ignored distractions and secondary task interruptions presented during a WM maintenance period, degraded memory accuracy in both the visual and auditory domain. However, in contrast to prior studies assessing WM for visual object stimuli, feature-based interference effects were not observed to be significantly greater in older adults. Analyses of neural oscillations in the alpha frequency band further revealed preserved mechanisms of interference processing in terms of post-stimulus alpha suppression, which was observed maximally for secondary task interruptions in visual and auditory modalities in both younger and older adults. These results suggest that age-related sensitivity of WM to interference may be limited to complex object stimuli, at least at low WM loads. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. The quantum mechanical measuring process as a scattering phenomenon inducing a collective coherent motion

    International Nuclear Information System (INIS)

    Requardt, M.

    1984-01-01

    In this paper we want to discuss the quantum mechanical measuring process within the realm of many body quantum theory. Our starting point is to consider this process as a special scattering phenomenon where within one of the partners, i.e. the many body measuring device, a collective coherent motion is induced by the interaction with the microobject. We start our investigation with the many body system having a large but finite number N of degrees of freedom which is the real situation. We then study in detail what will happen in the limit N->infinite, however emphasizing that this transition is actually only performed in the mind of the observer. This implies that certain tail events together with their phase correlations have to be truncated. We show that the dichotomy 'pure state' versus 'mixture' as outgoing scattering states will vanish in this limit in so far as it has no observable consequences provided one is only interested in the state of the microobject. Furthermore, we discuss the role of the observer, the notion of 'event', the relation between single preparation and ensemble picture, and the so-called 'reduction of the wave function' in the light of our approach, i.e. explaining the phenomena accompanying the measuring process in terms of many body quantum theory. (orig.)

  12. Biased Brownian motion mechanism for processivity and directionality of single-headed myosin-VI.

    Science.gov (United States)

    Iwaki, Mitsuhiro; Iwane, Atsuko Hikikoshi; Ikebe, Mitsuo; Yanagida, Toshio

    2008-01-01

    Conventional form to function as a vesicle transporter is not a 'single molecule' but a coordinated 'two molecules'. The coordinated two molecules make it complicated to reveal its mechanism. To overcome the difficulty, we adopted a single-headed myosin-VI as a model protein. Myosin-VI is an intracellular vesicle and organelle transporter that moves along actin filaments in a direction opposite to most other known myosin classes. The myosin-VI was expected to form a dimer to move processively along actin filaments with a hand-over-hand mechanism like other myosin organelle transporters. However, wild-type myosin-VI was demonstrated to be monomer and single-headed, casting doubt on its processivity. Using single molecule techniques, we show that green fluorescent protein (GFP)-fused single-headed myosin-VI does not move processively. However, when coupled to a 200 nm polystyrene bead (comparable to an intracellular vesicle in size) at a ratio of one head per bead, single-headed myosin-VI moves processively with large (40 nm) steps. Furthermore, we found that a single-headed myosin-VI-bead complex moved more processively in a high-viscous solution (40-fold higher than water) similar to cellular environment. Because diffusion of the bead is 60-fold slower than myosin-VI heads alone in water, we propose a model in which the bead acts as a diffusional anchor for the myosin-VI, enhancing the head's rebinding following detachment and supporting processive movement of the bead-monomer complex. This investigation will help us understand how molecular motors utilize Brownian motion in cells.

  13. Linking morphology and motion: a test of a four-bar mechanism in seahorses.

    Science.gov (United States)

    Roos, Gert; Leysen, Heleen; Van Wassenbergh, Sam; Herrel, Anthony; Jacobs, Patric; Dierick, Manuel; Aerts, Peter; Adriaens, Dominique

    2009-01-01

    Syngnathid fishes (seahorses, pipefish, and sea dragons) possess a highly modified cranium characterized by a long and tubular snout with minute jaws at its end. Previous studies indicated that these species are extremely fast suction feeders with their feeding strike characterized by a rapid elevation of the head accompanied by rotation of the hyoid. A planar four-bar model is proposed to explain the coupled motion of the neurocranium and the hyoid. Because neurocranial elevation as well as hyoid rotation are crucial for the feeding mechanism in previously studied Syngnathidae, a detailed evaluation of this model is needed. In this study, we present kinematic data of the feeding strike in the seahorse Hippocampus reidi. We combined these data with a detailed morphological analysis of the important linkages and joints involved in rotation of the neurocranium and the hyoid, and we compared the kinematic measurements with output of a theoretical four-bar model. The kinematic analysis shows that neurocranial rotation never preceded hyoid rotation, thus indicating that hyoid rotation triggers the explosive feeding strike. Our data suggest that while neurocranium and hyoid initially (first 1.5 ms) behave as predicted by the four-bar model, eventually, the hyoid rotation is underestimated by the model. Shortening, or a posterior displacement of the sternohyoid muscle (of which the posterior end is confluent with the hypaxial muscles in H. reidi), probably explains the discrepancy between the model and our kinematic measurements. As a result, while four-bar modeling indicates a clear coupling between hyoid rotation and neurocranial elevation, the detailed morphological determination of the linkages and joints of this four-bar model remain crucial in order to fully understand this mechanism in seahorse feeding.

  14. Statistical thermodynamics understanding the properties of macroscopic systems

    CERN Document Server

    Fai, Lukong Cornelius

    2012-01-01

    Basic Principles of Statistical PhysicsMicroscopic and Macroscopic Description of StatesBasic PostulatesGibbs Ergodic AssumptionGibbsian EnsemblesExperimental Basis of Statistical MechanicsDefinition of Expectation ValuesErgodic Principle and Expectation ValuesProperties of Distribution FunctionRelative Fluctuation of an Additive Macroscopic ParameterLiouville TheoremGibbs Microcanonical EnsembleMicrocanonical Distribution in Quantum MechanicsDensity MatrixDensity Matrix in Energy RepresentationEntropyThermodynamic FunctionsTemperatureAdiabatic ProcessesPressureThermodynamic IdentityLaws of Th

  15. Research on simulation calculation method of biomechanical characteristics of C1-3 motion segment damage mechanism

    Directory of Open Access Journals (Sweden)

    HUANG Ju-ying

    2013-11-01

    Full Text Available Objective To develop the finite element model (FEM of cervical spinal C1-3 motion segment, and to make biomechanical finite element analysis (FEA on C1-3 motion segment and thus simulate the biomechanical characteristics of C1-3 motion segment in distraction violence, compression violence, hyperextension violence and hyperflexion violence. Methods According to CT radiological data of a healthy adult, the vertebrae and intervertebral discs of cervical spinal C1-3 motion segment were respectively reconstructed by Mimics 10.01 software and Geomagic 10.0 software. The FEM of C1-3 motion segment was reconstructed by attaching the corresponding material properties of cervical spine in Ansys software. The biomechanical characteristics of cervical spinal C1-3 motion segment model were simulated under the 4 loadings of distraction violence, compression violence, hyperextension violence and hyperflexion violence by finite element method. Results In the loading of longitudinal stretch, the stress was relatively concentrated in the anterior arch of atlas, atlantoaxial joint and C3 lamina and spinous process. In the longitudinal compressive loads, the maximum stress of the upper cervical spine was located in the anterior arch of atlas. In the loading of hyperextension moment, the stress was larger in the massa lateralis atlantis, the lateral and posterior arch junction of atlas, the posterior arch nodules of the atlas, superior articular surface of axis and C2 isthmus. In the loading of hyperflexion moment, the stress was relatively concentrated in the odontoid process of axis, the posterior arch of atlas, the posterior arch nodules of atlas, C2 isthmic and C2 inferior articular process. Conclusion Finite element biomechanical testing of C1-3 motion segment can predict the biomechanical mechanism of upper cervical spine injury.

  16. Macroscopic reality and the dynamical reduction program

    International Nuclear Information System (INIS)

    Ghirardi, G.C.

    1995-10-01

    With reference to recently proposed theoretical models accounting for reduction in terms of a unified dynamics governing all physical processes, we analyze the problem of working out a worldview accommodating our knowledge about natural phenomena. We stress the relevant conceptual differences between the considered models and standard quantum mechanics. In spite of the fact that both theories describe individual physical systems within a genuine Hilbert space framework, the nice features of spontaneous reduction theories drastically limit the class of states which are dynamically stable. This allows one to work out a description of the world in terms of a mass density function in ordinary configuration space. A topology based on this function and differing radically from the one characterizing the Hilbert space is introduced and in terms of it the idea of similarity of macroscopic situations is made precise. Finally it is shown how the formalism and the proposed interpretation yield a natural criterion for establishing the psychophysical parallelism. The conclusion is that, within the considered theoretical models and at the nonrelativistic level, one can satisfy all sensible requirements for a consistent, unified, and objective description of reality at the macroscopic level. (author). 16 refs

  17. Measurement contextuality is implied by macroscopic realism

    International Nuclear Information System (INIS)

    Chen Zeqian; Montina, A.

    2011-01-01

    Ontological theories of quantum mechanics provide a realistic description of single systems by means of well-defined quantities conditioning the measurement outcomes. In order to be complete, they should also fulfill the minimal condition of macroscopic realism. Under the assumption of outcome determinism and for Hilbert space dimension greater than 2, they were all proved to be contextual for projective measurements. In recent years a generalized concept of noncontextuality was introduced that applies also to the case of outcome indeterminism and unsharp measurements. It was pointed out that the Beltrametti-Bugajski model is an example of measurement noncontextual indeterminist theory. Here we provide a simple proof that this model is the only one with such a feature for projective measurements and Hilbert space dimension greater than 2. In other words, there is no extension of quantum theory providing more accurate predictions of outcomes and simultaneously preserving the minimal labeling of events through projective operators. As a corollary, noncontextuality for projective measurements implies noncontextuality for unsharp measurements. By noting that the condition of macroscopic realism requires an extension of quantum theory, unless a breaking of unitarity is invoked, we arrive at the conclusion that the only way to solve the measurement problem in the framework of an ontological theory is by relaxing the hypothesis of measurement noncontextuality in its generalized sense.

  18. Macroscopic reality and the dynamical reduction program

    Energy Technology Data Exchange (ETDEWEB)

    Ghirardi, G C

    1995-10-01

    With reference to recently proposed theoretical models accounting for reduction in terms of a unified dynamics governing all physical processes, we analyze the problem of working out a worldview accommodating our knowledge about natural phenomena. We stress the relevant conceptual differences between the considered models and standard quantum mechanics. In spite of the fact that both theories describe individual physical systems within a genuine Hilbert space framework, the nice features of spontaneous reduction theories drastically limit the class of states which are dynamically stable. This allows one to work out a description of the world in terms of a mass density function in ordinary configuration space. A topology based on this function and differing radically from the one characterizing the Hilbert space is introduced and in terms of it the idea of similarity of macroscopic situations is made precise. Finally it is shown how the formalism and the proposed interpretation yield a natural criterion for establishing the psychophysical parallelism. The conclusion is that, within the considered theoretical models and at the nonrelativistic level, one can satisfy all sensible requirements for a consistent, unified, and objective description of reality at the macroscopic level. (author). 16 refs.

  19. Quantum Hamilton mechanics: Hamilton equations of quantum motion, origin of quantum operators, and proof of quantization axiom

    International Nuclear Information System (INIS)

    Yang, C.-D.

    2006-01-01

    This paper gives a thorough investigation on formulating and solving quantum problems by extended analytical mechanics that extends canonical variables to complex domain. With this complex extension, we show that quantum mechanics becomes a part of analytical mechanics and hence can be treated integrally with classical mechanics. Complex canonical variables are governed by Hamilton equations of motion, which can be derived naturally from Schroedinger equation. Using complex canonical variables, a formal proof of the quantization axiom p → p = -ih∇, which is the kernel in constructing quantum-mechanical systems, becomes a one-line corollary of Hamilton mechanics. The derivation of quantum operators from Hamilton mechanics is coordinate independent and thus allows us to derive quantum operators directly under any coordinate system without transforming back to Cartesian coordinates. Besides deriving quantum operators, we also show that the various prominent quantum effects, such as quantization, tunneling, atomic shell structure, Aharonov-Bohm effect, and spin, all have the root in Hamilton mechanics and can be described entirely by Hamilton equations of motion

  20. Macroscopic erosion of divertor and first wall armour in future tokamaks

    Science.gov (United States)

    Würz, H.; Bazylev, B.; Landman, I.; Pestchanyi, S.; Safronov, V.

    2002-12-01

    Sputtering, evaporation and macroscopic erosion determine the lifetime of the 'in vessel' armour materials CFC, tungsten and beryllium presently under discussion for future tokamaks. For CFC armour macroscopic erosion means brittle destruction and dust formation whereas for metallic armour melt layer erosion by melt motion and droplet splashing. Available results on macroscopic erosion from hot plasma and e-beam simulation experiments and from tokamaks are critically evaluated and a comprehensive discussion of experimental and numerical macroscopic erosion and its extrapolation to future tokamaks is given. Shielding of divertor armour materials by their own vapor exists during plasma disruptions. The evolving plasma shield protects the armour from high heat loads, absorbs the incoming energy and reradiates it volumetrically thus reducing drastically the deposited energy. As a result, vertical target erosion by vaporization turns out to be of the order of a few microns per disruption event and macroscopic erosion becomes the dominant erosion source.

  1. Macroscopic erosion of divertor and first wall armour in future tokamaks

    International Nuclear Information System (INIS)

    Wuerz, H.; Bazylev, B.; Landman, I.; Pestchanyi, S.; Safronov, V.

    2002-01-01

    Sputtering, evaporation and macroscopic erosion determine the lifetime of the 'in vessel' armour materials CFC, tungsten and beryllium presently under discussion for future tokamaks. For CFC armour macroscopic erosion means brittle destruction and dust formation whereas for metallic armour melt layer erosion by melt motion and droplet splashing. Available results on macroscopic erosion from hot plasma and e-beam simulation experiments and from tokamaks are critically evaluated and a comprehensive discussion of experimental and numerical macroscopic erosion and its extrapolation to future tokamaks is given. Shielding of divertor armour materials by their own vapor exists during plasma disruptions. The evolving plasma shield protects the armour from high heat loads, absorbs the incoming energy and reradiates it volumetrically thus reducing drastically the deposited energy. As a result, vertical target erosion by vaporization turns out to be of the order of a few microns per disruption event and macroscopic erosion becomes the dominant erosion source

  2. Using Unconstrained Tongue Motion as an Alternative Control Mechanism for Wheeled Mobility

    OpenAIRE

    Huo, Xueliang; Ghovanloo, Maysam

    2009-01-01

    Tongue drive system (TDS) is a tongue-operated, minimally invasive, unobtrusive, noncontact, and wireless assistive technology that infers users’ intentions by detecting and classifying their voluntary tongue motions, and translating them to user-defined commands. We have developed customized interface circuitry between an external TDS (eTDS) prototype and a commercial powered wheelchair (PWC) as well as three control strategies to evaluate the tongue motion as an alternative control input fo...

  3. From a stochastic to a macroscopic approach to brownian motion

    International Nuclear Information System (INIS)

    Bocquet, L.

    1998-01-01

    In this lecture, we examine the dynamics of suspensions of mesoscopic (Brownian) particles in a molecular fluid, starting from first principles. We introduce the technique of multiple time-scales to derive the Fokker-Planck equation for a single, or for a set of interacting Brownian particles, starting from the Liouville equation for the full system (Brownian particles and discrete bath). The limitations of the Fokker-Planck equation will then be emphasized. In particular, we shall point out that under ''standard'' experimental conditions, the Fokker-Planck description cannot be correct and that non-Markovian effects are expected. A microscopic description in the true experimental limit confirms this breakdown and leads to a ''generalized'' (non-Markovian and non-local in velocity space) Fokker-Planck equation, which describes the thermalization of the Brownian particle. (author)

  4. On the Calculation of Quantum Mechanical Ground States from Classical Geodesic Motion on Certain Spaces of Constant Negative Curvature

    CERN Document Server

    Tomaschitz, R

    1989-01-01

    We consider geodesic motion on three-dimensional Riemannian manifolds of constant negative curvature, topologically equivalent to S x ]0,1[, S a compact surface of genus two. To those trajectories which are bounded and recurrent in both directions of the time evolution a fractal limit set is associated whose Hausdorff dimension is intimately connected with the quantum mechanical energy ground state, determined by the Schrodinger operator on the manifold. We give a rather detailed and pictorial description of the hyperbolic spaces we have in mind, discuss various aspects of classical and quantum mechanical motion on them as far as they are needed to establish the connection between energy ground state and Hausdorff dimension and give finally some examples of ground state calculations in terms of Hausdorff dimensions of limit sets of classical trajectories.

  5. Imposing motion constraints to a force reflecting tele-robot through real-time simulation of a virtual mechanism

    International Nuclear Information System (INIS)

    Joly, L.; Andriot, C.

    1995-01-01

    In a tele-operation system, assistance can be given to the operator by constraining the tele-robot position to remain within a restricted subspace of its workspace. A new approach to motion constraint is presented in this paper. The control law is established simulating a virtual ideal mechanism acting as a jig, and connected to the master and slave arms via springs and dampers. Using this approach, it is possible to impose any (sufficiently smooth) motion constraint to the system, including non linear constraints (complex surfaces) involving coupling between translations and rotations and physical equivalence ensures that the controller is passive. Experimental results obtained with a 6-DOF tele-operation system are given. Other applications of the virtual mechanism concept include hybrid position-force control and haptic interfaces. (authors). 11 refs., 7 figs

  6. Imposing motion constraints to a force reflecting tele-robot through real-time simulation of a virtual mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Joly, L.; Andriot, C.

    1995-12-31

    In a tele-operation system, assistance can be given to the operator by constraining the tele-robot position to remain within a restricted subspace of its workspace. A new approach to motion constraint is presented in this paper. The control law is established simulating a virtual ideal mechanism acting as a jig, and connected to the master and slave arms via springs and dampers. Using this approach, it is possible to impose any (sufficiently smooth) motion constraint to the system, including non linear constraints (complex surfaces) involving coupling between translations and rotations and physical equivalence ensures that the controller is passive. Experimental results obtained with a 6-DOF tele-operation system are given. Other applications of the virtual mechanism concept include hybrid position-force control and haptic interfaces. (authors). 11 refs., 7 figs.

  7. On the calculation of quantum mechanical ground states from classical geodesic motion on certain spaces of constant negative curvature

    International Nuclear Information System (INIS)

    Tomaschitz, R.

    1989-01-01

    We consider geodesic motion on three-dimensional Riemannian manifolds of constant negative curvature, topologically equivalent to S x ]0,1[, S a compact surface of genus two. To those trajectories which are recurrent in both directions of the time evolution t → +∞, t → -∞ a fractal limit set is associated whose Hausdorff dimension is intimately connected with the quantum mechanical energy ground state, determined by the Schroedinger operator on the manifold. We give a rather detailed and pictorial description of the hyperbolic spaces we have in mind, discuss various aspects of classical and quantum mechanical motion on them as far as they are needed to establish the connection between energy ground state and Hausdorff dimension and give finally some examples of ground state calculations in terms of Hausdorff dimensions of limit sets of classical trajectories. (orig.)

  8. Mechanical effects in a rarified plasma

    International Nuclear Information System (INIS)

    Dubinov, A. E.; Sadovoy, S. A.

    2007-01-01

    A study is made of various mechanical effects that arise in a rarified plasma and set macroscopic solid bodies into motion: the magnetomechanical effect, the mechanical surface effect, the attraction of macrobodies, the levitation of a body in a plasma, and the orientation of a levitating body. Attention is focused on the design and construction of relevant experiments and experimental tests, as well as on the interpretation of the phenomena observed. Possible applications of the mechanical effects in physics and engineering are discussed

  9. Theory of superfluidity macroscopic quantum waves

    International Nuclear Information System (INIS)

    Ventura, I.

    1978-10-01

    A new description of superfluidity is proposed, based upon the fact that Bogoliubov's theory of superfluidity exhibits some so far unsuspected macroscopic quantum waves (MQWs), which have a topological nature and travel within the fluid at subsonic velocities. To quantize the bounded quasi-particles the field theoretic version of the Bohr-Sommerfeld quantization rule, is employed and also resort to a variational computation. In an instantaneous configuration the MQWs cut the condensate into blocks of phase, providing, by analogy with ferromagnetism, a nice explanation of what could be the lambda-transition. A crude estimate of the critical temperature gives T sub(c) approximately equal to 2-4K. An attempt is made to understand Tisza's two-fluid model in terms of the MQWs, and we rise the conjecture that they play an important role in the motion of second. We present also a qualitative prediction concerning to the behavior of the 'phononroton' peak below 1.0K, and propose two experiments to look for MQWs [pt

  10. Macroscopic quantum tunneling in a dc SQUID

    International Nuclear Information System (INIS)

    Chen, Y.C.

    1986-01-01

    The theory of macroscopic quantum tunneling is applied to a current-biased dc SQUID whose dynamics can be described by a two-dimensional mechanical system with a dissipative environment. Based on the phenomenological model proposed by Caldeira and Leggett, the dissipative environment is represented by a set of harmonic oscillators coupling to the system. After integrating out the environmental degrees of freedom, an effective Euclidean action is found for the two-dimensional system. The action is used to provide the quantum tunneling rate formalism for the dc SQUID. Under certain conditions, the tunneling rate reduces to that of a single current-biased Josephson junction with an adjustable effective critical current

  11. Seismic scanning tunneling macroscope - Theory

    KAUST Repository

    Schuster, Gerard T.

    2012-09-01

    We propose a seismic scanning tunneling macroscope (SSTM) that can detect the presence of sub-wavelength scatterers in the near-field of either the source or the receivers. Analytic formulas for the time reverse mirror (TRM) profile associated with a single scatterer model show that the spatial resolution limit to be, unlike the Abbe limit of λ/2, independent of wavelength and linearly proportional to the source-scatterer separation as long as the point scatterer is in the near-field region; if the sub-wavelength scatterer is a spherical impedance discontinuity then the resolution will also be limited by the radius of the sphere. Therefore, superresolution imaging can be achieved as the scatterer approaches the source. This is analogous to an optical scanning tunneling microscope that has sub-wavelength resolution. Scaled to seismic frequencies, it is theoretically possible to extract 100 Hz information from 20 Hz data by imaging of near-field seismic energy.

  12. Seismic scanning tunneling macroscope - Theory

    KAUST Repository

    Schuster, Gerard T.; Hanafy, Sherif M.; Huang, Yunsong

    2012-01-01

    We propose a seismic scanning tunneling macroscope (SSTM) that can detect the presence of sub-wavelength scatterers in the near-field of either the source or the receivers. Analytic formulas for the time reverse mirror (TRM) profile associated with a single scatterer model show that the spatial resolution limit to be, unlike the Abbe limit of λ/2, independent of wavelength and linearly proportional to the source-scatterer separation as long as the point scatterer is in the near-field region; if the sub-wavelength scatterer is a spherical impedance discontinuity then the resolution will also be limited by the radius of the sphere. Therefore, superresolution imaging can be achieved as the scatterer approaches the source. This is analogous to an optical scanning tunneling microscope that has sub-wavelength resolution. Scaled to seismic frequencies, it is theoretically possible to extract 100 Hz information from 20 Hz data by imaging of near-field seismic energy.

  13. A macroscopic constitutive model of temperature-induced phase transition of polycrystalline Ni{sub 2}MnGa by directional solidification

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yuping, E-mail: zhuyuping@126.com; Gu, Yunling; Liu, Hongguang

    2015-02-25

    Directional solidification technology has been widely used to improve the properties of polycrystalline Ni{sub 2}MnGa materials. Mechanical training can adjust the internal organizational structures of the materials, reduce the stress of twin boundaries motion, and then result in larger strain at lower outfield levels. In this paper, we test the microscopic structure of Ni{sub 2}MnGa polycrystalline ferromagnetic shape memory alloy produced by directional solidification and compress it along two axes successively for mechanical training. The influences of pre-compressive stresses on the temperature-induced strains are analyzed. The macroscopic mechanical behaviors show anisotropy. According to the generating mechanism of the macroscopic strain, a three-dimensional constitutive model is established. Based on thermodynamic method, the kinetic equations of the martensitic transformation and inverse transformation are presented considering the driving force and energy dissipation. The prediction curves of temperature-induce strains along two different directions are investigated. And the results coincide well with the experiment data. It well explains the macroscopic anisotropy mechanical behaviors and fits for using in engineering.

  14. How to: Using Mode Analysis to Quantify, Analyze, and Interpret the Mechanisms of High-Density Collective Motion

    Directory of Open Access Journals (Sweden)

    Arianna Bottinelli

    2017-12-01

    Full Text Available While methods from statistical mechanics were some of the earliest analytical tools used to understand collective motion, the field has substantially expanded in scope beyond phase transitions and fluctuating order parameters. In part, this expansion is driven by the increasing variety of systems being studied, which in turn, has increased the need for innovative approaches to quantify, analyze, and interpret a growing zoology of collective behaviors. For example, concepts from material science become particularly relevant when considering the collective motion that emerges at high densities. Here, we describe methods originally developed to study inert jammed granular materials that have been borrowed and adapted to study dense aggregates of active particles. This analysis is particularly useful because it projects difficult-to-analyze patterns of collective motion onto an easier-to-interpret set of eigenmodes. Carefully viewed in the context of non-equilibrium systems, mode analysis identifies hidden long-range motions and localized particle rearrangements based solely on the knowledge of particle trajectories. In this work, we take a “how to” approach and outline essential steps, diagnostics, and know-how used to apply this analysis to study densely-packed active systems.

  15. IMMEDIATE EFFECT OF CERVICAL MANIPULATION ON PAIN AND RANGE OF MOTION IN PATIENTS WITH CHRONIC MECHANICAL NECK PAIN

    Directory of Open Access Journals (Sweden)

    Kabir Isah Mayana

    2017-06-01

    Full Text Available Background: Neck pain has been reported as a prevalent musculoskeletal disorder globally with more than half of the general population being affected once or more within their life span. Methods: A randomized clinical trial research design was used which investigated the immediate effect of cervical manipulation on neck pain and cervical range of motion among patients with chronic mechanical neck pain. 20 male and female participants between the ages of 26 to 60 years with chronic mechanical neck pain attending physiotherapy clinics were recruited. They were randomly assigned into two groups (A and B of 10 patients each. Group A received soft tissue massage, and cervical manipulation and group B served as the control group, and they received only soft tissue massage. There were two outcomes measured; Pain intensity was rated using visual analog scale (VAS before and immediately after the intervention. Pre and Post intervention measurements of cervical spine range of motion using Goniometer were also taken. Results: Findings of the study revealed significant immediate improvement of pain and Cervical Range of Motions (p<0.05 in all dimensions in the experimental group while Pain, flexion and right side Cervical flexion significantly improved in the control group. It was also found out after comparing the outcomes between the two groups that, the experimental group had significantly (p<0.05 better improvement than the control group in post-intervention pain, cervical flexion, cervical extension and cervical (right and left lateral rotations. Conclusion: Cervical manipulation is effective in immediate pain relief and improvement in cervical range of motion in patients with mechanical neck pain

  16. Prediction of strong acceleration motion depended on focal mechanism; Shingen mechanism wo koryoshita jishindo yosoku ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Kaneda, Y; Ejiri, J [Obayashi Corp., Tokyo (Japan)

    1996-10-01

    This paper describes simulation results of strong acceleration motion with varying uncertain fault parameters mainly for a fault model of Hyogo-ken Nanbu earthquake. For the analysis, based on the fault parameters, the strong acceleration motion was simulated using the radiation patterns and the breaking time difference of composite faults as parameters. A statistic waveform composition method was used for the simulation. For the theoretical radiation patterns, directivity was emphasized which depended on the strike of faults, and the maximum acceleration was more than 220 gal. While, for the homogeneous radiation patterns, the maximum accelerations were isotopically distributed around the fault as a center. For variations in the maximum acceleration and the predominant frequency due to the breaking time difference of three faults, the response spectral value of maximum/minimum was about 1.7 times. From the viewpoint of seismic disaster prevention, underground structures including potential faults and non-arranging properties can be grasped using this simulation. Significance of the prediction of strong acceleration motion was also provided through this simulation using uncertain factors, such as breaking time of composite faults, as parameters. 4 refs., 4 figs., 1 tab.

  17. Energy barriers and mechanisms in solid-solid polymorphic transitions exhibiting cooperative motion

    NARCIS (Netherlands)

    van den Ende, J.A.; Ensing, B.; Cuppen, H.M.

    2016-01-01

    Understanding solid–solid polymorphic transitions within molecular crystals on the molecular scale is a challenging task. It is, however, crucial for the understanding of transitions that are thought to occur through cooperative motion, which offer an interesting perspective for future applications.

  18. Molecular Motion in Polymers: Mechanical Behavior of Polymers Near the Glass-Rubber Transition Temperature.

    Science.gov (United States)

    Sperling, L. H.

    1982-01-01

    The temperature at which the onset of coordinated segmental motion begins is called the glass-rubber transition temperature (Tg). Natural rubber at room temperature is a good example of a material above its Tg. Describes an experiment examining the response of a typical polymer to temperature variations above and below Tg. (Author/JN)

  19. Flexture plate motion-transfer mechanism, beam-splitter assembly, and interferometer incorporating the same

    Energy Technology Data Exchange (ETDEWEB)

    Carangelo, Robert M. (Glastonbury, CT); Dettori, Mark D. (Farmington, CT); Grigely, Lawrence J. (South Windsor, CT); Murray, Terence C. (Winchester, MA); Solomon, Peter R. (West Hartford, CT); Van Dine, C. Peter (Bolton, CT); Wright, David D. (Vershire, VT)

    1996-01-01

    A multiplicity of one-piece flexure plates are assembled in pairs to provide a support system on which a retroreflector may be mounted for reciprocal motion. Combined with balance bodies, the flexure plates provide a support system having portions that are dynamically and statically balanced with one another, irrespective of orientation, so as to thereby immunize the unit against extraneous forces. The motion transfer assembly is especially adapted for use to support a moving retroreflector in a two-arm interferometer that may further include a beamsplitter assembly constructed from a one-piece, integrally formed body, the body having convergent, optically flat planar surfaces of specular reflectance, and means for adjustably mounting a beamsplitter therein. The spectrometer is of modular construction, and employs an integrated clocking sub-assembly as well as a light-weight voice-coil motor.

  20. Using unconstrained tongue motion as an alternative control mechanism for wheeled mobility.

    Science.gov (United States)

    Huo, Xueliang; Ghovanloo, Maysam

    2009-06-01

    Tongue drive system (TDS) is a tongue-operated, minimally invasive, unobtrusive, noncontact, and wireless assistive technology that infers users' intentions by detecting and classifying their voluntary tongue motions, and translating them to user-defined commands. We have developed customized interface circuitry between an external TDS (eTDS) prototype and a commercial powered wheelchair (PWC) as well as three control strategies to evaluate the tongue motion as an alternative control input for wheeled mobility. We tested the eTDS performance in driving PWCs on 12 able-bodied human subjects, of which 11 were novice. The results showed that all subjects could complete navigation tasks by operating the PWC using their tongue motions. Despite little prior experience, the average time using the eTDS and the tongue was only approximately three times longer than using a joystick and the fingers. Navigation time was strongly dependant on the number of issued commands, which reduced by gaining experience. Particularly, the unintended issued commands (the Midas touch problem) were rare, demonstrating the effectiveness of the tongue tracking and external magnetic field cancellation algorithms as well as the safety of the TDS for wheeled mobility.

  1. Macroscopic realism and quantum measurement: measurers as a natural kind

    International Nuclear Information System (INIS)

    Jaeger, Gregg

    2014-01-01

    The notion of macroscopic realism has been used in attempts to achieve consistency between physics and everyday experience and to locate some boundary between the realms of classical mechanics and quantum meachanics. Its ostensibly underlying conceptual components, realism and macroscopicity, have most often appeared in the foundations of physics in relation to quantum measurement: reality became a prominent topic of discussion in quantum physics after the notion of element of reality was defined and used by Einstein, Podolsky and Rosen in that context, and macroscopicity is often explicitly assumed to be an essential property of any measuring apparatus. However, macroscopicity turns out to be a rather vaguer and less consistently understood notion than typically assumed by physicists who have not explicitly explored the notion themselves. For this reason, it behooves those investigating the foundations of quantum mechanics from a realist perspective to look for alternative notions for grounding quantum measurement. Here, the merits of treating the measuring instrument as a ‘natural kind’ as a means of avoiding anthropocentrism in the foundations of quantum measurement are pointed out as a means of advancing quantum measurement theory. (paper)

  2. The origins of macroscopic quantum coherence in high temperature superconductivity

    International Nuclear Information System (INIS)

    Turner, Philip; Nottale, Laurent

    2015-01-01

    Highlights: • We propose a new theoretical approach to superconductivity in p-type cuprates. • Electron pairing mechanisms in the superconducting and pseudogap phases are proposed. • A scale free network of dopants is key to macroscopic quantum coherence. - Abstract: A new, theoretical approach to macroscopic quantum coherence and superconductivity in the p-type (hole doped) cuprates is proposed. The theory includes mechanisms to account for e-pair coupling in the superconducting and pseudogap phases and their inter relations observed in these materials. Electron pair coupling in the superconducting phase is facilitated by local quantum potentials created by static dopants in a mechanism which explains experimentally observed optimal doping levels and the associated peak in critical temperature. By contrast, evidence suggests that electrons contributing to the pseudogap are predominantly coupled by fractal spin waves (fractons) induced by the fractal arrangement of dopants. On another level, the theory offers new insights into the emergence of a macroscopic quantum potential generated by a fractal distribution of dopants. This, in turn, leads to the emergence of coherent, macroscopic spin waves and a second associated macroscopic quantum potential, possibly supported by charge order. These quantum potentials play two key roles. The first involves the transition of an expected diffusive process (normally associated with Anderson localization) in fractal networks, into e-pair coherence. The second involves the facilitation of tunnelling between localized e-pairs. These combined effects lead to the merger of the super conducting and pseudo gap phases into a single coherent condensate at optimal doping. The underlying theory relating to the diffusion to quantum transition is supported by Coherent Random Lasing, which can be explained using an analogous approach. As a final step, an experimental program is outlined to validate the theory and suggests a new

  3. Observation of squeezed light and quantum description of the macroscopical body movement

    International Nuclear Information System (INIS)

    Bykov, V.P.

    1992-01-01

    The possibility of a nondemolition measurement (observation) of macroscopical objects in widely distributed quantum mechanical states arises from the fact of the squezzed light observation. Macroscopical bodies -bodies of classical mechanics - are usually in states with narrow wave packets. It is shown that the absence of macroscopical bodies in widely distributed states is due to the focusing influence of the body's gravity field on its wave packet. An evidence that the gravity is essential in the classic limit of quantum mechanics is given. (author). 14 refs, 7 figs

  4. Towards a theory of macroscopic gravity

    International Nuclear Information System (INIS)

    Zalaletdinov, R.M.

    1993-01-01

    By averaging out Cartan's structure equations for a four-dimensional Riemannian space over space regions, the structure equations for the averaged space have been derived with the procedure being valid on an arbitrary Riemannian space. The averaged space is characterized by a metric, Riemannian and non-Riemannian curvature 2-forms, and correlation 2-, 3- and 4-forms, an affine deformation 1-form being due to the non-metricity of one of two connection 1-forms. Using the procedure for the space-time averaging of the Einstein equations produces the averaged ones with the terms of geometric correction by the correlation tensors. The equations of motion for averaged energy momentum, obtained by averaging out the coritracted Bianchi identifies, also include such terms. Considering the gravitational induction tensor to be the Riemannian curvature tensor (the non-Riemannian one is then the field tensor), a theorem is proved which relates the algebraic structure of the averaged microscopic metric to that of the induction tensor. It is shown that the averaged Einstein equations can be put in the form of the Einstein equations with the conserved macroscopic energy-momentum tensor of a definite structure including the correlation functions. By using the high-frequency approximation of Isaacson with second-order correction to the microscopic metric, the self-consistency and compatibility of the equations and relations obtained are shown. Macrovacuum turns out to be Ricci non-flat, the macrovacuum source being defined in terms of the correlation functions. In the high-frequency limit the equations are shown to become Isaacson's ones with the macrovacuum source becoming Isaacson's stress tensor for gravitational waves. 17 refs

  5. The Effect of Flexible Pavement Mechanics on the Accuracy of Axle Load Sensors in Vehicle Weigh-in-Motion Systems.

    Science.gov (United States)

    Burnos, Piotr; Rys, Dawid

    2017-09-07

    Weigh-in-Motion systems are tools to prevent road pavements from the adverse phenomena of vehicle overloading. However, the effectiveness of these systems can be significantly increased by improving weighing accuracy, which is now insufficient for direct enforcement of overloaded vehicles. Field tests show that the accuracy of Weigh-in-Motion axle load sensors installed in the flexible (asphalt) pavements depends on pavement temperature and vehicle speeds. Although this is a known phenomenon, it has not been explained yet. The aim of our study is to fill this gap in the knowledge. The explanation of this phenomena which is presented in the paper is based on pavement/sensors mechanics and the application of the multilayer elastic half-space theory. We show that differences in the distribution of vertical and horizontal stresses in the pavement structure are the cause of vehicle weight measurement errors. These studies are important in terms of Weigh-in-Motion systems for direct enforcement and will help to improve the weighing results accuracy.

  6. The Effects of Inlet Box Aerodynamics on the Mechanical Performance of a Variable Pitch in Motion Fan

    OpenAIRE

    Sheard, A. G.

    2012-01-01

    This paper describes research involving an in-service failure of a “variable pitch in motion” fan’s blade bearing. Variable pitch in motion fans rotate at a constant speed, with the changing blade angle varying the load. A pitch-change mechanism facilitates the change in blade angle. A blade bearing supports each blade enabling it to rotate. The author observed that as the fan aerodynamic stage loading progressively increased, so did the rate of blade-bearing wear. The reported research addre...

  7. Discrete allowed and forbidden states in the classical mechanical domain in the charged particle motion in a magnetic field

    International Nuclear Information System (INIS)

    Varma, R.K.; Punithavelu, A.M.; Banerjee, S.B.

    1994-01-01

    The properties of the motion of charged particles injected almost parallel to the magnetic field are studied by measuring the electron current as a function of the cathode voltage (electron energy), as electrons from the gun traverse a distance L to the detector. The plate current is found to exhibit oscillatory behaviour in contradistinction with the behaviour expected according to the standard classical mechanical paradigm, with the peaks fitting a relation obtained from a quantum like theory predicting such a behaviour. (author). 4 refs, 1 fig, 1 tab

  8. Mass motions in impulsive flarelike brightenings as observed by OSO 8. [mechanism response for solar flares

    Science.gov (United States)

    Bruner, E. C., Jr.; Lites, B. W.

    1979-01-01

    C IV 1548-A line profiles obtained with the University of Colorado spectrometer aboard OSO 8 reveal transient, redshifted brightenings in the chromosphere-corona transition region above active regions and sunspots. In these events the intensity rises by factors of up to 5 in less than the profile sampling interval of 27 sec. These events indicate that the emitting material is moving downward at velocities of up to 30 km/sec. The increase in line intensity and the amount of motion are consistent with the interpretation of these events as pressure waves propagating down magnetic flux loops.

  9. Discovery of a new motion mechanism of biomotors similar to the earth revolving around the sun without rotation

    International Nuclear Information System (INIS)

    Guo, Peixuan; Schwartz, Chad; Haak, Jeannie; Zhao, Zhengyi

    2013-01-01

    Biomotors have been classified into linear and rotational motors. For 35 years, it has been popularly believed that viral dsDNA-packaging apparatuses are pentameric rotation motors. Recently, a third class of hexameric motor has been found in bacteriophage phi29 that utilizes a mechanism of revolution without rotation, friction, coiling, or torque. This review addresses how packaging motors control dsDNA one-way traffic; how four electropositive layers in the channel interact with the electronegative phosphate backbone to generate four steps in translocating one dsDNA helix; how motors resolve the mismatch between 10.5 bases and 12 connector subunits per cycle of revolution; and how ATP regulates sequential action of motor ATPase. Since motors with all number of subunits can utilize the revolution mechanism, this finding helps resolve puzzles and debates concerning the oligomeric nature of packaging motors in many phage systems. This revolution mechanism helps to solve the undesirable dsDNA supercoiling issue involved in rotation. - Highlights: • New motion mechanism of revolution without rotation found for phi29 DNA packaging. • Revolution motor finding expands classical linear and rotation biomotor classes. • Revolution motors transport dsDNA unidirectionally without supercoiling. • New mechanism solves many puzzles, mysteries, and debates in biomotor studies. • Motors with all numbers of subunits can utilize the revolution mechanism

  10. Discovery of a new motion mechanism of biomotors similar to the earth revolving around the sun without rotation

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Peixuan, E-mail: peixuan.guo@uky.edu; Schwartz, Chad; Haak, Jeannie; Zhao, Zhengyi

    2013-11-15

    Biomotors have been classified into linear and rotational motors. For 35 years, it has been popularly believed that viral dsDNA-packaging apparatuses are pentameric rotation motors. Recently, a third class of hexameric motor has been found in bacteriophage phi29 that utilizes a mechanism of revolution without rotation, friction, coiling, or torque. This review addresses how packaging motors control dsDNA one-way traffic; how four electropositive layers in the channel interact with the electronegative phosphate backbone to generate four steps in translocating one dsDNA helix; how motors resolve the mismatch between 10.5 bases and 12 connector subunits per cycle of revolution; and how ATP regulates sequential action of motor ATPase. Since motors with all number of subunits can utilize the revolution mechanism, this finding helps resolve puzzles and debates concerning the oligomeric nature of packaging motors in many phage systems. This revolution mechanism helps to solve the undesirable dsDNA supercoiling issue involved in rotation. - Highlights: • New motion mechanism of revolution without rotation found for phi29 DNA packaging. • Revolution motor finding expands classical linear and rotation biomotor classes. • Revolution motors transport dsDNA unidirectionally without supercoiling. • New mechanism solves many puzzles, mysteries, and debates in biomotor studies. • Motors with all numbers of subunits can utilize the revolution mechanism.

  11. Rank distributions: A panoramic macroscopic outlook

    Science.gov (United States)

    Eliazar, Iddo I.; Cohen, Morrel H.

    2014-01-01

    This paper presents a panoramic macroscopic outlook of rank distributions. We establish a general framework for the analysis of rank distributions, which classifies them into five macroscopic "socioeconomic" states: monarchy, oligarchy-feudalism, criticality, socialism-capitalism, and communism. Oligarchy-feudalism is shown to be characterized by discrete macroscopic rank distributions, and socialism-capitalism is shown to be characterized by continuous macroscopic size distributions. Criticality is a transition state between oligarchy-feudalism and socialism-capitalism, which can manifest allometric scaling with multifractal spectra. Monarchy and communism are extreme forms of oligarchy-feudalism and socialism-capitalism, respectively, in which the intrinsic randomness vanishes. The general framework is applied to three different models of rank distributions—top-down, bottom-up, and global—and unveils each model's macroscopic universality and versatility. The global model yields a macroscopic classification of the generalized Zipf law, an omnipresent form of rank distributions observed across the sciences. An amalgamation of the three models establishes a universal rank-distribution explanation for the macroscopic emergence of a prevalent class of continuous size distributions, ones governed by unimodal densities with both Pareto and inverse-Pareto power-law tails.

  12. Reversible optical control of macroscopic polarization in ferroelectrics

    Science.gov (United States)

    Rubio-Marcos, Fernando; Ochoa, Diego A.; Del Campo, Adolfo; García, Miguel A.; Castro, Germán R.; Fernández, José F.; García, José E.

    2018-01-01

    The optical control of ferroic properties is a subject of fascination for the scientific community, because it involves the establishment of new paradigms for technology1-9. Domains and domain walls are known to have a great impact on the properties of ferroic materials1-24. Progress is currently being made in understanding the behaviour of the ferroelectric domain wall, especially regarding its dynamic control10-12,17,19. New research is being conducted to find effective methodologies capable of modulating ferroelectric domain motion for future electronics. However, the practical use of ferroelectric domain wall motion should be both stable and reversible (rewritable) and, in particular, be able to produce a macroscopic response that can be monitored easily12,17. Here, we show that it is possible to achieve a reversible optical change of ferroelectric domains configuration. This effect leads to the tuning of macroscopic polarization and its related properties by means of polarized light, a non-contact external control. Although this is only the first step, it nevertheless constitutes the most crucial one in the long and complex process of developing the next generation of photo-stimulated ferroelectric devices.

  13. Stochastic mechanics and the Kepler problem: Diffusions generated by the quantum motion

    International Nuclear Information System (INIS)

    Garbaczewski, P.

    1986-01-01

    We construct a class of solutions of the Schroedinger equation for the Coulomb-Kepler problem. Their ψ = ρ 1/2 exp(iS/ℎ) structure implies that the quantal dynamics of wave functions is completely determined by the related classical Hamiltonian system. A construction of the associated controlled stochastic processes is then possible, their drift velocity being entirely defined in terms of (explicitly known) probability density ρ(x,y,z,t) and phase S(x,y,z,t). In particular, for the stationary states of the quantum problem, in its four-oscillator reconstruction, we identify the regime in which the related classical Hamiltonian can be effectively replaced by the Hamiltonian of the classical Kepler motion. (orig.)

  14. A novel remote center of motion mechanism for the force-reflective master robot of haptic tele-surgery systems.

    Science.gov (United States)

    Hadavand, Mostafa; Mirbagheri, Alireza; Behzadipour, Saeed; Farahmand, Farzam

    2014-06-01

    An effective master robot for haptic tele-surgery applications needs to provide a solution for the inversed movements of the surgical tool, in addition to sufficient workspace and manipulability, with minimal moving inertia. A novel 4 + 1-DOF mechanism was proposed, based on a triple parallelogram linkage, which provided a Remote Center of Motion (RCM) at the back of the user's hand. The kinematics of the robot was analyzed and a prototype was fabricated and evaluated by experimental tests. With a RCM at the back of the user's hand the actuators far from the end effector, the robot could produce the sensation of hand-inside surgery with minimal moving inertia. The target workspace was achieved with an acceptable manipulability. The trajectory tracking experiments revealed small errors, due to backlash at the joints. The proposed mechanism meets the basic requirements of an effective master robot for haptic tele-surgery applications. Copyright © 2013 John Wiley & Sons, Ltd.

  15. Strain coupling between nitrogen vacancy centers and the mechanical motion of a diamond optomechanical crystal resonator

    Science.gov (United States)

    Cady, J. V.; Lee, K. W.; Ovartchaiyapong, P.; Bleszynski Jayich, A. C.

    Several experiments have recently demonstrated coupling between nitrogen vacancy (NV) centers in diamond and mechanical resonators via crystal strain. In the strong coupling regime, such devices could realize applications critical to emerging quantum technologies, including phonon-mediated spin-spin interactions and mechanical cooling with the NV center1. An outstanding challenge for these devices is generating higher strain coupling in high frequency devices while maintaining the excellent coherence properties of the NV center and high mechanical quality factors. As a step toward these objectives, we demonstrate single-crystal diamond optomechanical crystal resonators with embedded NV centers. These devices host highly-confined GHz-scale mechanical modes that are isolated from mechanical clamping losses and generate strain profiles that allow for large strain coupling to NV centers far from noise-inducing surfaces.

  16. Macroscopic (and microscopic massless modes

    Directory of Open Access Journals (Sweden)

    Michael C. Abbott

    2015-05-01

    Full Text Available We study certain spinning strings exploring the flat directions of AdS3×S3×S3×S1, the massless sector cousins of su(2 and sl(2 sector spinning strings. We describe these, and their vibrational modes, using the D(2,1;α2 algebraic curve. By exploiting a discrete symmetry of this structure which reverses the direction of motion on the spheres, and alters the masses of the fermionic modes s→κ−s, we find out how to treat the massless fermions which were previously missing from this formalism. We show that folded strings behave as a special case of circular strings, in a sense which includes their mode frequencies, and we are able to recover this fact in the worldsheet formalism. We use these frequencies to calculate one-loop corrections to the energy, with a version of the Beisert–Tseytlin resummation.

  17. Relationship Between Filler-Matrix Interface and Macroscopical Properties of Polymer Nanocomposites

    KAUST Repository

    Ventura, Isaac Aguilar

    2017-01-01

    The macroscopic properties of Multiwall Carbon Nanotube (MWCNT) polymer nano-composites and multiscale composites have been studied from a multifunctional standpoint. The objective is to understand and correlate the mechanisms in which the addition

  18. Role of stochastic fluctuations in the charge on macroscopic particles in dusty plasmas

    International Nuclear Information System (INIS)

    Vaulina, O.S.; Nefedov, A.P.; Petrov, O.F.; Khrapak, S.A.

    1999-01-01

    The currents which charge a macroscopic particle placed in a plasma consist of discrete charges; hence, the charge can undergo random fluctuations about its equilibrium value. These random fluctuations can be described by a simple model which, if the mechanisms for charging of macroscopic particles are known, makes it possible to determine the dependence of the temporal and amplitude characteristics of the fluctuations on the plasma parameters. This model can be used to study the effect of charge fluctuations on the dynamics of the macroscopic particles. The case of so-called plasma-dust crystals (i.e., highly ordered structures which develop because of strong interactions among macroscopic particles) in laboratory gaseous discharge plasmas is considered as an example. The molecular dynamics method shows that, under certain conditions, random fluctuations in the charge can effectively heat a system of macroscopic particles, thereby impeding the ordering process

  19. Stiffness analysis of spring mechanism for semi automatic gripper motion of tendon driven remote manipulator

    International Nuclear Information System (INIS)

    Yu, Seung Nam; Lee, Jong Kwang

    2012-01-01

    Remote handling manipulators are widely used for performing hazardous tasks, and it is essential to ensure the reliable performance of such systems. Toward this end, tendon driven mechanisms are adopted in such systems to reduce the weight of the distal parts of the manipulator while maintaining the handling performance. In this study, several approaches for the design of a gripper system for a tendon driven remote handling system are introduced. Basically, this gripper has an underactuated spring mechanism that is combined with a slave manipulator triggered by a master operator. Based on the requirements under the specified tendon driven mechanism, the connecting position of the spring system on the gripper mechanism and kinematic influence coefficient (KIC) analysis are performed. As a result, a suitable combination of components for the proper design of the target system is presented and verified

  20. Cloud Macroscopic Organization: Order Emerging from Randomness

    Science.gov (United States)

    Yuan, Tianle

    2011-01-01

    Clouds play a central role in many aspects of the climate system and their forms and shapes are remarkably diverse. Appropriate representation of clouds in climate models is a major challenge because cloud processes span at least eight orders of magnitude in spatial scales. Here we show that there exists order in cloud size distribution of low-level clouds, and that it follows a power-law distribution with exponent gamma close to 2. gamma is insensitive to yearly variations in environmental conditions, but has regional variations and land-ocean contrasts. More importantly, we demonstrate this self-organizing behavior of clouds emerges naturally from a complex network model with simple, physical organizing principles: random clumping and merging. We also demonstrate symmetry between clear and cloudy skies in terms of macroscopic organization because of similar fundamental underlying organizing principles. The order in the apparently complex cloud-clear field thus has its root in random local interactions. Studying cloud organization with complex network models is an attractive new approach that has wide applications in climate science. We also propose a concept of cloud statistic mechanics approach. This approach is fully complementary to deterministic models, and the two approaches provide a powerful framework to meet the challenge of representing clouds in our climate models when working in tandem.

  1. Investigation of dissipative forces near macroscopic media

    International Nuclear Information System (INIS)

    Becker, R.S.

    1982-12-01

    The interaction of classical charged particles with the fields they induce in macroscopic dielectric media is investigated. For 10- to 1000-eV electrons, the angular perturbation of the trajectory by the image potential for surface impact parameters of 50 to 100 A is shown to be of the order of 0.001 rads over a distance of 100 A. The energy loss incurred by low-energy particles due to collective excitations such as surface plasmons is shown to be observable with a transition probability of 0.01 to 0.001 (Becker, et al., 1981b). The dispersion of real surface plasmon modes in planar and cylindrical geometries is discussed and is derived for pinhole geometry described in terms of a single-sheeted hyperboloid of revolution. An experimental apparatus for the measurement of collective losses for medium-energy electrons translating close to a dielectric surface is described and discussed. Data showing such losses at electron energies of 500 to 900 eV in silver foils containing many small apertures are presented and shown to be in good agreement with classical stopping power calculations and quantum mechanical calculations carried out in the low-velocity limit. The data and calculations are compared and contrasted with earlier transmission and reflection measurements, and the course of further investigation is discussed

  2. The Proell Effect: A Macroscopic Maxwell's Demon

    Science.gov (United States)

    Rauen, Kenneth M.

    2011-12-01

    Maxwell's Demon is a legitimate challenge to the Second Law of Thermodynamics when the "demon" is executed via the Proell effect. Thermal energy transfer according to the Kinetic Theory of Heat and Statistical Mechanics that takes place over distances greater than the mean free path of a gas circumvents the microscopic randomness that leads to macroscopic irreversibility. No information is required to sort the particles as no sorting occurs; the entire volume of gas undergoes the same transition. The Proell effect achieves quasi-spontaneous thermal separation without sorting by the perturbation of a heterogeneous constant volume system with displacement and regeneration. The classical analysis of the constant volume process, such as found in the Stirling Cycle, is incomplete and therefore incorrect. There are extra energy flows that classical thermo does not recognize. When a working fluid is displaced across a regenerator with a temperature gradient in a constant volume system, complimentary compression and expansion work takes place that transfers energy between the regenerator and the bulk gas volumes of the hot and cold sides of the constant volume system. Heat capacity at constant pressure applies instead of heat capacity at constant volume. The resultant increase in calculated, recyclable energy allows the Carnot Limit to be exceeded in certain cycles. Super-Carnot heat engines and heat pumps have been designed and a US patent has been awarded.

  3. Improvements of Real Time First Motion Focal Mechanism and Noise Characteristics of New Sites at the Puerto Rico Seismic Network

    Science.gov (United States)

    Williams, D. M.; Lopez, A. M.; Huerfano, V.; Lugo, J.; Cancel, J.

    2011-12-01

    Seismic networks need quick and efficient ways to obtain information related to seismic events for the purposes of seismic activity monitoring, risk assessment, and scientific knowledge among others. As part of an IRIS summer internship program, two projects were performed to provide a tool for quick faulting mechanism and improve seismic data at the Puerto Rico Seismic Network (PRSN). First, a simple routine to obtain a focal mechanisms, the geometry of the fault, based on first motions was developed and implemented for data analysts routine operations at PRSN. The new tool provides the analyst a quick way to assess the probable faulting mechanism that occurred while performing the interactive earthquake location procedure. The focal mechanism is generated on-the-fly when data analysts pick P wave arrivals onsets and motions. Once first motions have been identified, an in-house PRSN utility is employed to obtain the double couple representation and later plotted using GMT's psmeca utility. Second, we addressed the issue of seismic noise related to thermal fluctuations inside seismic vaults. Seismic sites can be extremely noisy due to proximity to cultural activities and unattended thermal fluctuations inside sensor housings, thus resulting in skewed readings. In the past, seismologists have used different insulation techniques to reduce the amount of unwanted noise that a seismometers experience due to these thermal changes with items such as Styrofoam, and fiber glass among others. PRSN traditionally uses Styrofoam boxes to cover their seismic sensors, however, a proper procedure to test how these method compare to other new techniques has never been approached. The deficiency of properly testing these techniques in the Caribbean and especially Puerto Rico is that these thermal fluctuations still happen because of the intense sun and humidity. We conducted a test based on the methods employed by the IRIS Transportable Array, based on insulation by sand burial of

  4. Macroscopic quantum phenomena from the large N perspective

    International Nuclear Information System (INIS)

    Chou, C H; Hu, B L; Subasi, Y

    2011-01-01

    Macroscopic quantum phenomena (MQP) is a relatively new research venue, with exciting ongoing experiments and bright prospects, yet with surprisingly little theoretical activity. What makes MQP intellectually stimulating is because it is counterpoised against the traditional view that macroscopic means classical. This simplistic and hitherto rarely challenged view need be scrutinized anew, perhaps with much of the conventional wisdoms repealed. In this series of papers we report on a systematic investigation into some key foundational issues of MQP, with the hope of constructing a viable theoretical framework for this new endeavour. The three major themes discussed in these three essays are the large N expansion, the correlation hierarchy and quantum entanglement for systems of 'large' sizes, with many components or degrees of freedom. In this paper we use different theories in a variety of contexts to examine the conditions or criteria whereby a macroscopic quantum system may take on classical attributes, and, more interestingly, that it keeps some of its quantum features. The theories we consider here are, the O(N) quantum mechanical model, semiclassical stochastic gravity and gauge / string theories; the contexts include that of a 'quantum roll' in inflationary cosmology, entropy generation in quantum Vlasov equation for plasmas, the leading order and next-to-leading order large N behaviour, and hydrodynamic / thermodynamic limits. The criteria for classicality in our consideration include the use of uncertainty relations, the correlation between classical canonical variables, randomization of quantum phase, environment-induced decoherence, decoherent history of hydrodynamic variables, etc. All this exercise is to ask only one simple question: Is it really so surprising that quantum features can appear in macroscopic objects? By examining different representative systems where detailed theoretical analysis has been carried out, we find that there is no a priori

  5. Macroscopic quantum waves in non local theories

    International Nuclear Information System (INIS)

    Ventura, I.

    1979-01-01

    By means of an expansion in the density, it is shown that Macroscopic Quantum Waves also apear in non local theories. This result reinforces the conjecture that these waves should exist in liquid 4 He. (Author) [pt

  6. Macroscopic quantum waves in non local theories

    International Nuclear Information System (INIS)

    Ventura, I.

    1979-01-01

    By means of an expansion in the density, it is shown that Macroscopic Quantum Waves also appear in non local theories. This result reinforces the conjecture that these waves should exist in liquid 4 He [pt

  7. Assessments of macroscopicity for quantum optical states

    DEFF Research Database (Denmark)

    Laghaout, Amine; Neergaard-Nielsen, Jonas Schou; Andersen, Ulrik Lund

    2015-01-01

    With the slow but constant progress in the coherent control of quantum systems, it is now possible to create large quantum superpositions. There has therefore been an increased interest in quantifying any claims of macroscopicity. We attempt here to motivate three criteria which we believe should...... enter in the assessment of macroscopic quantumness: The number of quantum fluctuation photons, the purity of the states, and the ease with which the branches making up the state can be distinguished. © 2014....

  8. Nuclear fission as a macroscopic quantum tunneling

    International Nuclear Information System (INIS)

    Takigawa, N.

    1995-01-01

    We discuss nuclear fission from the point of view of a macroscopic quantum tunneling, one of whose major interests is to study the effects of environments on the tunneling rate of a macroscopic variable. We show that a vibrational excitation of the fissioning nucleus significantly enhances the fission rate. We show this effect by two different methods. The one is to treat the vibrational excitation as an environmental degree of freedom, the other treats the fission as a two dimensional quantum tunneling. (author)

  9. Study of the conservation of mechanical energy in the motion of a pendulum using a smartphone

    Science.gov (United States)

    Pierratos, Theodoros; Polatoglou, Hariton M.

    2018-01-01

    A common method that scientists use to validate a theory is to utilize known principles and laws to produce results on specific settings, which can be assessed using the appropriate experimental methods and apparatuses. Smartphones have various sensors built-in and could be used for measuring and logging data in physics experiments. In this work, we propose the use of smartphones for students to study a simple pendulum’s conservation of mechanical energy. It is well known that common smartphones do not have a velocity sensor, which could make the verification of the conservation of mechanical energy a simpler task. To overcome this, one can use an accelerometer to measure the centripetal acceleration on the mass and from that, deduce the maximum velocity. In this study, we show that this can be achieved with reasonable uncertainty, using a mobile device. Thus, we developed an experiment which corroborates with the conservation of mechanical energy and can be performed in the classroom.

  10. Quantum Sensing of Mechanical Motion with a Single InAs Quantum Dot

    Science.gov (United States)

    2017-03-01

    Wenner, J. M. Martinis, and A. N. Cleland, “ Quantum ground state and single- phonon control of a mechanical resonator.,” Nature, vol. 464, no...G. Nogues, S. Seidelin, J. Poizat, O. Arcizet, and M. Richard, “Strain-mediated coupling in a quantum dot- mechanical oscillator hybrid system...Pos 4 Dep 5 School of N upling quantu ctive for funda dded a semico nical resonat vances in thi es large ch ell as the spin for quantum s antum Dots

  11. Separation of atmospheric, oceanic and hydrological polar motion excitation mechanisms based on a combination of geometric and gravimetric space observations

    Science.gov (United States)

    Göttl, F.; Schmidt, M.; Seitz, F.; Bloßfeld, M.

    2015-04-01

    The goal of our study is to determine accurate time series of geophysical Earth rotation excitations to learn more about global dynamic processes in the Earth system. For this purpose, we developed an adjustment model which allows to combine precise observations from space geodetic observation systems, such as Satellite Laser Ranging (SLR), Global Navigation Satellite Systems, Very Long Baseline Interferometry, Doppler Orbit determination and Radiopositioning Integrated on Satellite, satellite altimetry and satellite gravimetry in order to separate geophysical excitation mechanisms of Earth rotation. Three polar motion time series are applied to derive the polar motion excitation functions (integral effect). Furthermore we use five time variable gravity field solutions from Gravity Recovery and Climate Experiment to determine not only the integral mass effect but also the oceanic and hydrological mass effects by applying suitable filter techniques and a land-ocean mask. For comparison the integral mass effect is also derived from degree 2 potential coefficients that are estimated from SLR observations. The oceanic mass effect is also determined from sea level anomalies observed by satellite altimetry by reducing the steric sea level anomalies derived from temperature and salinity fields of the oceans. Due to the combination of all geodetic estimated excitations the weaknesses of the individual processing strategies can be reduced and the technique-specific strengths can be accounted for. The formal errors of the adjusted geodetic solutions are smaller than the RMS differences of the geophysical model solutions. The improved excitation time series can be used to improve the geophysical modeling.

  12. Cam-Follower Mechanism Design for Narrow Loom Beat Up Motion ...

    African Journals Online (AJOL)

    The topology of the kinematics is developed by using the graph theory method of kinematic synthesis. The forces required to drive the plate-cam and follower system were modeled and the components such as the plate-cam, camshaft, the follower and the drive mechanism were synthesized for smooth operation of the ...

  13. Introducing Mechanics: II. Towards a Justified Choice between Alternative Theories of Motion

    Science.gov (United States)

    Emmett, Katrina; Klaassen, Kees; Eijkelhof, Harrie

    2009-01-01

    In an earlier article we presented an innovative approach for introducing mechanics at upper secondary level based on the idea of tapping core causal knowledge, and we described the working of the first part of the module. In this article we describe the second part of the module, in which we make use of the students' intuitive plausibility…

  14. A Direct Derivation of the Equations of Motion for 3D-Flexible Mechanical Systems

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Pedersen, Mads Leergaard

    1998-01-01

    equations for flexible mechanical systems are derived using the principle of virtual work, which introduces inertia in a straightforward manner, because this principle treats inertia as a force. The flexible formulation is exemplified by the use of circular beam elements and some basic matrices are derived...

  15. Introducing mechanics: II. Towards a justified choice between alternative theories of motion

    NARCIS (Netherlands)

    Emmett, K.M.; Klaassen, K.; Eijkelhof, H.

    2009-01-01

    In an earlier article we presented an innovative approach for introducing mechanics at upper secondary level based on the idea of tapping core causal knowledge, and we described the working of the first part of the module. In this article we describe the second part of the module, in which we make

  16. Einstein-Podolsky-Rosen-entangled motion of two massive objects

    Science.gov (United States)

    Schnabel, Roman

    2015-07-01

    In 1935, Einstein, Podolsky, and Rosen (EPR) considered two particles in an entangled state of motion to illustrate why they questioned the completeness of quantum theory. In past decades, microscopic systems with entanglement in various degrees of freedom have successfully been generated, representing compelling evidence to support the completeness of quantum theory. Today, the generation of an EPR-entangled state of motion of two massive objects of up to the kilogram scale seems feasible with state-of-the-art technology. Recently, the generation and verification of EPR-entangled mirror motion in interferometric gravitational wave detectors was proposed, with the aim of testing quantum theory in the regime of macroscopic objects, and to make available nonclassical probe systems for future tests of modified quantum theories that include (nonrelativistic) gravity. The work presented here builds on these earlier results and proposes a specific Michelson interferometer that includes two high-quality laser mirrors of about 0.1 kg mass each. The mirrors are individually suspended as pendula and located close to each other, and cooled to about 4 K. The physical concepts for the generation of the EPR-entangled center-of-mass motion of these two mirrors are described. Apart from a test of quantum mechanics in the macroscopic world, the setup is envisioned to test predictions of yet-to-be-elaborated modified quantum theories that include gravitational effects.

  17. Problems related to macroscopic electric fields in the magnetosphere

    International Nuclear Information System (INIS)

    Faelthammar, C.

    1977-01-01

    The macroscopic electric fields in the magnetosphere originate from internal as well as external sources. The fields are intimately coupled with the dynamics of magnetospheric plasma convection. They also depend on the complicated electrical properties of the hot collisionless plasma. Macroscopic electric fields are responsible for some important kinds of energization of charged particles that take place in the magnetosphere and affect not only particles of auroral energy but also, by multistep processes, trapped high-energy particles. A particularly interesting feature of magnetospheric electric fields is that they can have substantial components along the geomagnetic field, as has recently been confirmed by observations. Several physical mechanisms have been identified by which such electric fields can be supported even when collisions between particles are negligible. Comments are made on the magnetic mirror effect, anomalous resistivity, the collisionless thermoelectric effect, and electric double layers, emphasizing key features and differences and their significance in the light of recent observational data

  18. Macroscopic fundamental strings in cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Aharonov, Y; Englert, F; Orloff, J

    1987-12-24

    We show that, when D greater than or equal to 4, theories of closed strings of closed strings in D, non-compact space-time dimensions exhibit a phase transition. The high-temperature phase is characterized by a condensate of arbitrarily long strings with Hausdorff dimension two (area filling curves). We suggest that this stringy phase is the ancestor of the adiabatic era. Fundamental strings could then both drive the inflation and seed, in a way reminiscent of the cosmic string mechanism, the large structures in the universe.

  19. Lagrangian analysis of invariant third-order equations of motion in relativistic classical particle mechanics

    International Nuclear Information System (INIS)

    Matsyuk, R.Ya.

    1985-01-01

    The problem on the existence of the invariant third-order Euler-Poisson equations in the pseudo-Euclidean space is investigated. The locally variational problem is determined by the Lagrangian density over the space of the second-order jets. The one - parameter family of the invariant third-order Euler-Poisson equations is groved to be the only one in the three-dimensional pseudo-Euclidean space. No invariant third-order Euler-Poisson equations exist in the four-dimensional pseudo-Euclidean space. It is shown that the Mathisson equation and the equation of geodesic circles in particular cases may be considered in the context of the Ostrogradiskij mechanics and the Kavaguchi geometry

  20. A Review on Macroscopic Pedestrian Flow Modelling

    Directory of Open Access Journals (Sweden)

    Anna Kormanová

    2013-12-01

    Full Text Available This paper reviews several various approaches to macroscopic pedestrian modelling. It describes hydrodynamic models based on similarity of pedestrian flow with fluids and gases; first-order flow models that use fundamental diagrams and conservation equation; and a model similar to LWR vehicular traffic model, which allows non-classical shocks. At the end of the paper there is stated a comparison of described models, intended to find appropriate macroscopic model to eventually be a part of a hybrid model. The future work of the author is outlined.

  1. Macroscopic effects in attosecond pulse generation

    International Nuclear Information System (INIS)

    Ruchon, T; Varju, K; Mansten, E; Swoboda, M; L'Huillier, A; Hauri, C P; Lopez-Martens, R

    2008-01-01

    We examine how the generation and propagation of high-order harmonics in a partly ionized gas medium affect their strength and synchronization. The temporal properties of the resulting attosecond pulses generated in long gas targets can be significantly influenced by macroscopic effects, in particular by the intensity in the medium and the degree of ionization which control the dispersion. Under some conditions, the use of gas targets longer than the absorption length can lead to the generation of compressed attosecond pulses. We show these macroscopic effects experimentally, using a 6 mm-long argon-filled gas cell as the generating medium

  2. Macroscopic effects in attosecond pulse generation

    Energy Technology Data Exchange (ETDEWEB)

    Ruchon, T; Varju, K; Mansten, E; Swoboda, M; L' Huillier, A [Department of Physics, Lund University, PO Box 118, SE-221 00 Lund (Sweden); Hauri, C P; Lopez-Martens, R [Laboratoire d' Optique Appliquee, Ecole Nationale Superieure des Techniques Avancees (ENSTA)-Ecole Polytechnique CNRS UMR 7639, 91761 Palaiseau (France)], E-mail: anne.lhuillier@fysik.lth.se

    2008-02-15

    We examine how the generation and propagation of high-order harmonics in a partly ionized gas medium affect their strength and synchronization. The temporal properties of the resulting attosecond pulses generated in long gas targets can be significantly influenced by macroscopic effects, in particular by the intensity in the medium and the degree of ionization which control the dispersion. Under some conditions, the use of gas targets longer than the absorption length can lead to the generation of compressed attosecond pulses. We show these macroscopic effects experimentally, using a 6 mm-long argon-filled gas cell as the generating medium.

  3. Internal fuel motion as an inherent shutdown mechanism for LMFBR accidents: PINEX-3, PINEX-2, and HUT 5-2A experiments

    International Nuclear Information System (INIS)

    Ferrell, P.C.; Porten, D.R.; Martin, F.J.

    1981-01-01

    The PINEX-2 experiment verified the concept of axial internal molten fuel motion within annular fuel, representing an inherent shutdown mechanism for hypothetical transient overpower excursions on the order of 5$/s. The PINEX-3 experiment, simulating a 50 cents/s transient overpower, showed that limitations on the effectiveness of fuel motion may arise from freezing of the fuel and blockage of the internal movement. Analysis of these experiments was performed to assess the physical processes that dominate fuel relocation potential and to apply them to prototypic LMFBR pin conditions. Results indicate that internal fuel motion should be reliable as a shutdown mechanism in LMFBR's for a range of reactivity insertion rates beyond presently available experimental data

  4. Macroscopic optical response and photonic bands

    International Nuclear Information System (INIS)

    Pérez-Huerta, J S; Luis Mochán, W; Ortiz, Guillermo P; Mendoza, Bernardo S

    2013-01-01

    We develop a formalism for the calculation of the macroscopic dielectric response of composite systems made of particles of one material embedded periodically within a matrix of another material, each of which is characterized by a well-defined dielectric function. The nature of these dielectric functions is arbitrary, and could correspond to dielectric or conducting, transparent or opaque, absorptive and dispersive materials. The geometry of the particles and the Bravais lattice of the composite are also arbitrary. Our formalism goes beyond the long-wavelength approximation as it fully incorporates retardation effects. We test our formalism through the study of the propagation of electromagnetic waves in two-dimensional photonic crystals made of periodic arrays of cylindrical holes in a dispersionless dielectric host. Our macroscopic theory yields a spatially dispersive macroscopic response which allows the calculation of the full photonic band structure of the system, as well as the characterization of its normal modes, upon substitution into the macroscopic field equations. We can also account approximately for the spatial dispersion through a local magnetic permeability and analyze the resulting dispersion relation, obtaining a region of left handedness. (paper)

  5. Berkeley Experiments on Superfluid Macroscopic Quantum Effects

    International Nuclear Information System (INIS)

    Packard, Richard

    2006-01-01

    This paper provides a brief history of the evolution of the Berkeley experiments on macroscopic quantum effects in superfluid helium. The narrative follows the evolution of the experiments proceeding from the detection of single vortex lines to vortex photography to quantized circulation in 3He to Josephson effects and superfluid gyroscopes in both 4He and 3He

  6. Macroscopic sizes of field of superrelativistic charges

    International Nuclear Information System (INIS)

    Strel'tsov, V.N.

    1995-01-01

    Based on the equation of Lienard-Wiechert equipotentials, it is shown that the field of superrelativistic charges reaches macroscopic sizes (e.g., R || = 2 m at E e = 50 GeV). This phenomenon serves an initial cause of the known considerable growth of formation length at high energies. 3 refs., 1 tab

  7. The Two-Time Interpretation and Macroscopic Time-Reversibility

    Directory of Open Access Journals (Sweden)

    Yakir Aharonov

    2017-03-01

    Full Text Available The two-state vector formalism motivates a time-symmetric interpretation of quantum mechanics that entails a resolution of the measurement problem. We revisit a post-selection-assisted collapse model previously suggested by us, claiming that unlike the thermodynamic arrow of time, it can lead to reversible dynamics at the macroscopic level. In addition, the proposed scheme enables us to characterize the classical-quantum boundary. We discuss the limitations of this approach and its broad implications for other areas of physics.

  8. The Effects of Inlet Box Aerodynamics on the Mechanical Performance of a Variable Pitch in Motion Fan

    Directory of Open Access Journals (Sweden)

    A. G. Sheard

    2012-01-01

    Full Text Available This paper describes research involving an in-service failure of a “variable pitch in motion” fan’s blade bearing. Variable pitch in motion fans rotate at a constant speed, with the changing blade angle varying the load. A pitch-change mechanism facilitates the change in blade angle. A blade bearing supports each blade enabling it to rotate. The author observed that as the fan aerodynamic stage loading progressively increased, so did the rate of blade-bearing wear. The reported research addressed two separate, but linked, needs. First, the ongoing need to increase fan pressure development capability required an increase in fan loading. This increase was within the context of an erosive operating regime which systematically reduced fan pressure development capability. The second need was to identify the root cause of blade-bearing failures. The author addressed the linked needs using a computational analysis, improving the rotor inflow aerodynamic characteristics through an analysis of the inlet box and design of inlet guide vanes to control flow nonuniformities at the fan inlet. The results of the improvement facilitated both an increase in fan-pressure-developing capability and identification of the root cause of the blade-bearing failures.

  9. Spinal fusion limits upper body range of motion during gait without inducing compensatory mechanisms in adolescent idiopathic scoliosis patients.

    Science.gov (United States)

    Holewijn, R M; Kingma, I; de Kleuver, M; Schimmel, J J P; Keijsers, N L W

    2017-09-01

    Previous studies show a limited alteration of gait at normal walking speed after spinal fusion surgery for adolescent idiopathic scoliosis (AIS), despite the presumed essential role of spinal mobility during gait. This study analyses how spinal fusion affects gait at more challenging walking speeds. More specifically, we investigated whether thoracic-pelvic rotations are reduced to a larger extent at higher gait speeds and whether compensatory mechanisms above and below the stiffened spine are present. 18 AIS patients underwent gait analysis at increasing walking speeds (0.45 to 2.22m/s) before and after spinal fusion. The range of motion (ROM) of the upper (thorax, thoracic-pelvic and pelvis) and lower body (hip, knee and ankle) was determined in all three planes. Spatiotemporal parameters of interest were stride length and cadence. Spinal fusion diminished transverse plane thoracic-pelvic ROM and this difference was more explicit at higher walking speeds. Transversal pelvis ROM was also decreased but this effect was not affected by speed. Lower body ROM, step length and cadence remained unaffected. Despite the reduction of upper body ROM after spine surgery during high speed gait, no altered spatiotemporal parameters or increased compensatory ROM above or below the fusion (i.e. in the shoulder girdle or lower extremities) was identified. Thus, it remains unclear how patients can cope so well with such major surgery. Future studies should focus on analyzing the kinematics of individual spinal levels above and below the fusion during gait to investigate possible compensatory mechanisms within the spine. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Three lectures on macroscopic aspects of nuclear dynamics

    International Nuclear Information System (INIS)

    Swiatecki, W.J.

    1979-03-01

    These lectures concentrate on macroscopic aspects of nuclear dynamics, those aspects that come into prominence when the number of nucleons, A, is large, A >> 1. An attempt is made to set up a theory of the dynamics of nuclear shape changes, for small (sub-sonic) collective velocities. To set up the equations of motion one needs three forces: conservative, dissipative, and inertial. The first lecture deals with statics, i.e., it discusses methods of treating the Potential Energy Function of nuclear systems. From the Potential Energy the conservative forces that drive the time evolution of a nuclear configuration can be deduced. The division of the underlying potential energy into Local, Proximity, and Global terms is stressed. The second lecture deals with dynamical aspects, especially with the nuclear Dissipation Function, which describes how dissipative frictional forces oppose the conservative driving forces. The underlying physics is the approximate validity of the Independent-Particle model. This, combined with the Randomization Hypothesis, leads to simple formulas that suggest that dissipative forces may often overshadow the inertial forces. The third lecture outlines the kind of dynamics that results from the balance of these forces, and describes a number of applications to nuclear fission and heavy-ion collisions of this New Dynamics. Particularly simple equations of motion are set up, and some of the consequences are explored. 18 references, 31 figures, 3 tables

  11. Macroscopic and non-linear quantum games

    International Nuclear Information System (INIS)

    Aerts, D.; D'Hooghe, A.; Posiewnik, A.; Pykacz, J.

    2005-01-01

    Full text: We consider two models of quantum games. The first one is Marinatto and Weber's 'restricted' quantum game in which only the identity and the spin-flip operators are used. We show that this quantum game allows macroscopic mechanistic realization with the use of a version of the 'macroscopic quantum machine' described by Aerts already in 1980s. In the second model we use non-linear quantum state transformations which operate on points of spin-1/2 on the Bloch sphere and which can be used to distinguish optimally between two non-orthogonal states. We show that efficiency of these non-linear strategies out-perform any linear ones. Some hints on the possible theory of non-linear quantum games are given. (author)

  12. Bimodality in macroscopic dynamics of nuclear fission

    International Nuclear Information System (INIS)

    Bastrukov, S.I.; Salamatin, V.S.; Strteltsova, O.I.; Molodtsova, I.V.; Podgainy, D.V.; )

    2000-01-01

    The elastodynamic collective model of nuclear fission is outlined whose underlying idea is that the stiff structure of nuclear shells imparts to nucleus properties typical of a small piece of an elastic solid. Emphasis is placed on the macroscopic dynamics of nuclear deformations resulting in fission by two energetically different modes. The low-energy S-mode is the fission due to disruption of elongated quadrupole spheroidal shape. The characteristic features of the high-energy T-mode of division by means of torsional shear deformations is the compact scission configuration. Analytic and numerical estimates for the macroscopic fission-barrier heights are presented, followed by discussion of fingerprints of the above dynamical bimodality in the available data [ru

  13. Study of a Car Body Tilting System Using a Variable Link Mechanism: Fundamental Characteristics of Pendulum Motion and Strategy for Perfect Tilting

    Science.gov (United States)

    Yoshida, Hidehisa; Nagai, Masao

    This paper analyzes the fundamental dynamic characteristics of a tilting railway vehicle using a variable link mechanism for compensating both the lateral acceleration experienced by passengers and the wheel load imbalance between the inner and outer rails. The geometric relations between the center of rotation, the center of gravity, and the positions of all four links of the tilting system are analyzed. Then, equations of the pendulum motions of the railway vehicle body with a four-link mechanism are derived. A theoretically discussion is given on the geometrical shapes employed in the link mechanism that can simultaneously provide zero lateral acceleration and zero wheel load fluctuation. Then, the perfect tilting condition, which is the control target of the feedforward tilting control, is derived from the linear equation of tilting motion.

  14. Macroscopic Quantum Resonators (MAQRO): 2015 update

    International Nuclear Information System (INIS)

    Kaltenbaek, Rainer; Aspelmeyer, Markus; Kiesel, Nikolai; Barker, Peter F.; Bose, Sougato; Bassi, Angelo; Bateman, James; Bongs, Kai; Cruise, Adrian Michael; Braxmaier, Claus; Brukner, Caslav; Christophe, Bruno; Rodrigues, Manuel; Chwalla, Michael; Johann, Ulrich; Cohadon, Pierre-Francois; Heidmann, Antoine; Lambrecht, Astrid; Reynaud, Serge; Curceanu, Catalina; Dholakia, Kishan; Mazilu, Michael; Diosi, Lajos; Doeringshoff, Klaus; Peters, Achim; Ertmer, Wolfgang; Rasel, Ernst M.; Gieseler, Jan; Novotny, Lukas; Rondin, Loic; Guerlebeck, Norman; Herrmann, Sven; Laemmerzahl, Claus; Hechenblaikner, Gerald; Hossenfelder, Sabine; Kim, Myungshik; Milburn, Gerard J.; Mueller, Holger; Paternostro, Mauro; Pikovski, Igor; Pilan Zanoni, Andre; Riedel, Charles Jess; Roura, Albert; Schleich, Wolfgang P.; Schmiedmayer, Joerg; Schuldt, Thilo; Schwab, Keith C.; Tajmar, Martin; Tino, Guglielmo M.; Ulbricht, Hendrik; Ursin, Rupert; Vedral, Vlatko

    2016-01-01

    Do the laws of quantum physics still hold for macroscopic objects - this is at the heart of Schroedinger's cat paradox - or do gravitation or yet unknown effects set a limit for massive particles? What is the fundamental relation between quantum physics and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times and the quality of vacuum and microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) may overcome these limitations and allow addressing such fundamental questions. MAQRO harnesses recent developments in quantum optomechanics, high-mass matter-wave interferometry as well as state-of-the-art space technology to push macroscopic quantum experiments towards their ultimate performance limits and to open new horizons for applying quantum technology in space. The main scientific goal is to probe the vastly unexplored 'quantum-classical' transition for increasingly massive objects, testing the predictions of quantum theory for objects in a size and mass regime unachievable in ground-based experiments. The hardware will largely be based on available space technology. Here, we present the MAQRO proposal submitted in response to the 4th Cosmic Vision call for a medium-sized mission (M4) in 2014 of the European Space Agency (ESA) with a possible launch in 2025, and we review the progress with respect to the original MAQRO proposal for the 3rd Cosmic Vision call for a medium-sized mission (M3) in 2010. In particular, the updated proposal overcomes several critical issues of the original proposal by relying on established experimental techniques from high-mass matter-wave interferometry and by introducing novel ideas for particle loading and manipulation. Moreover, the mission design was improved to better fulfill the stringent environmental requirements for macroscopic quantum experiments. (orig.)

  15. Macroscopic Quantum Resonators (MAQRO): 2015 update

    Energy Technology Data Exchange (ETDEWEB)

    Kaltenbaek, Rainer [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Aspelmeyer, Markus; Kiesel, Nikolai [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Barker, Peter F.; Bose, Sougato [University College London, Department of Physics and Astronomy, London (United Kingdom); Bassi, Angelo [University of Trieste, Department of Physics, Trieste (Italy); INFN - Trieste Section, Trieste (Italy); Bateman, James [University of Swansea, Department of Physics, College of Science, Swansea (United Kingdom); Bongs, Kai; Cruise, Adrian Michael [University of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Braxmaier, Claus [University of Bremen, Center of Applied Space Technology and Micro Gravity (ZARM), Bremen (Germany); Institute of Space Systems, German Aerospace Center (DLR), Bremen (Germany); Brukner, Caslav [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Austrian Academy of Sciences, Institute of Quantum Optics and Quantum Information (IQOQI), Vienna (Austria); Christophe, Bruno; Rodrigues, Manuel [The French Aerospace Lab, ONERA, Chatillon (France); Chwalla, Michael; Johann, Ulrich [Airbus Defence and Space GmbH, Immenstaad (Germany); Cohadon, Pierre-Francois; Heidmann, Antoine; Lambrecht, Astrid; Reynaud, Serge [ENS-PSL Research University, Laboratoire Kastler Brossel, UPMC-Sorbonne Universites, CNRS, College de France, Paris (France); Curceanu, Catalina [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Dholakia, Kishan; Mazilu, Michael [University of St. Andrews, School of Physics and Astronomy, St. Andrews (United Kingdom); Diosi, Lajos [Wigner Research Center for Physics, P.O. Box 49, Budapest (Hungary); Doeringshoff, Klaus; Peters, Achim [Humboldt-Universitaet zu Berlin, Institut fuer Physik, Berlin (Germany); Ertmer, Wolfgang; Rasel, Ernst M. [Leibniz Universitaet Hannover, Institut fuer Quantenoptik, Hannover (Germany); Gieseler, Jan; Novotny, Lukas; Rondin, Loic [ETH Zuerich, Photonics Laboratory, Zuerich (Switzerland); Guerlebeck, Norman; Herrmann, Sven; Laemmerzahl, Claus [University of Bremen, Center of Applied Space Technology and Micro Gravity (ZARM), Bremen (Germany); Hechenblaikner, Gerald [Airbus Defence and Space GmbH, Immenstaad (Germany); European Southern Observatory (ESO), Garching bei Muenchen (Germany); Hossenfelder, Sabine [KTH Royal Institute of Technology and Stockholm University, Nordita, Stockholm (Sweden); Kim, Myungshik [Imperial College London, QOLS, Blackett Laboratory, London (United Kingdom); Milburn, Gerard J. [University of Queensland, ARC Centre for Engineered Quantum Systems, Brisbane (Australia); Mueller, Holger [University of California, Department of Physics, Berkeley, CA (United States); Paternostro, Mauro [Queen' s University, Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Belfast (United Kingdom); Pikovski, Igor [Harvard-Smithsonian Center for Astrophysics, ITAMP, Cambridge, MA (United States); Pilan Zanoni, Andre [Airbus Defence and Space GmbH, Immenstaad (Germany); CERN - European Organization for Nuclear Research, EN-STI-TCD, Geneva (Switzerland); Riedel, Charles Jess [Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada); Roura, Albert [Universitaet Ulm, Institut fuer Quantenphysik, Ulm (Germany); Schleich, Wolfgang P. [Universitaet Ulm, Institut fuer Quantenphysik, Ulm (Germany); Texas A and M University Institute for Advanced Study (TIAS), Institute for Quantum Science and Engineering (IQSE), and Department of Physics and Astronomy, College Station, TX (United States); Schmiedmayer, Joerg [Vienna University of Technology, Vienna Center for Quantum Science and Technology, Institute of Atomic and Subatomic Physics, Vienna (Austria); Schuldt, Thilo [Institute of Space Systems, German Aerospace Center (DLR), Bremen (Germany); Schwab, Keith C. [California Institute of Technology, Applied Physics, Pasadena, CA (United States); Tajmar, Martin [Technische Universitaet Dresden, Institut fuer Luft- und Raumfahrttechnik, Dresden (Germany); Tino, Guglielmo M. [Universita di Firenze, Dipartimento di Fisica e Astronomia and LENS, INFN, Sesto Fiorentino, Firenze (Italy); Ulbricht, Hendrik [University of Southampton, Physics and Astronomy, Southampton (United Kingdom); Ursin, Rupert [Austrian Academy of Sciences, Institute of Quantum Optics and Quantum Information (IQOQI), Vienna (Austria); Vedral, Vlatko [University of Oxford, Atomic and Laser Physics, Clarendon Laboratory, Oxford (United Kingdom); National University of Singapore, Center for Quantum Technologies, Singapore (SG)

    2016-12-15

    Do the laws of quantum physics still hold for macroscopic objects - this is at the heart of Schroedinger's cat paradox - or do gravitation or yet unknown effects set a limit for massive particles? What is the fundamental relation between quantum physics and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times and the quality of vacuum and microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) may overcome these limitations and allow addressing such fundamental questions. MAQRO harnesses recent developments in quantum optomechanics, high-mass matter-wave interferometry as well as state-of-the-art space technology to push macroscopic quantum experiments towards their ultimate performance limits and to open new horizons for applying quantum technology in space. The main scientific goal is to probe the vastly unexplored 'quantum-classical' transition for increasingly massive objects, testing the predictions of quantum theory for objects in a size and mass regime unachievable in ground-based experiments. The hardware will largely be based on available space technology. Here, we present the MAQRO proposal submitted in response to the 4th Cosmic Vision call for a medium-sized mission (M4) in 2014 of the European Space Agency (ESA) with a possible launch in 2025, and we review the progress with respect to the original MAQRO proposal for the 3rd Cosmic Vision call for a medium-sized mission (M3) in 2010. In particular, the updated proposal overcomes several critical issues of the original proposal by relying on established experimental techniques from high-mass matter-wave interferometry and by introducing novel ideas for particle loading and manipulation. Moreover, the mission design was improved to better fulfill the stringent environmental requirements for macroscopic quantum experiments. (orig.)

  16. Special relativity - the foundation of macroscopic physics

    International Nuclear Information System (INIS)

    Dixon, W.G.

    1978-01-01

    This book aims to show that an understanding of the basic laws of macroscopic systems can be gained more easily within relativistic physics than within Newtonian physics. The unity of dynamics, thermodynamics and electromagnetism under the umbrella of special relativity is examined under chapter headings entitled: the physics of space and time, affine spaces in mathematics and physics, foundations of dynamics, relativistic simple fluids, and, electrodynamics of polarizable fluids. (U.K.)

  17. Microscopic and macroscopic models for pedestrian crowds

    OpenAIRE

    Makmul, Juntima

    2016-01-01

    This thesis is concerned with microscopic and macroscopic models for pedes- trian crowds. In the first chapter, we consider pedestrians exit choices and model human behaviour in an evacuation process. Two microscopic models, discrete and continuous, are studied in this chapter. The former is a cellular automaton model and the latter is a social force model. Different numerical test cases are investigated and their results are compared. In chapter 2, a hierarchy of models for...

  18. Macroscopic acoustoelectric charge transport in graphene

    Science.gov (United States)

    Bandhu, L.; Lawton, L. M.; Nash, G. R.

    2013-09-01

    We demonstrate macroscopic acoustoelectric transport in graphene, transferred onto piezoelectric lithium niobate substrates, between electrodes up to 500 μm apart. Using double finger interdigital transducers we have characterised the acoustoelectric current as a function of both surface acoustic wave intensity and frequency. The results are consistent with a relatively simple classical relaxation model, in which the acoustoelectric current is proportional to both the surface acoustic wave intensity and the attenuation of the wave caused by the charge transport.

  19. Macroscopic behaviour of a charged Boltzmann gas

    International Nuclear Information System (INIS)

    Banyai, L.; Gartner, P.; Protopopescu, V.

    1980-08-01

    We consider a classical charged gas (with self-consistent Coulomb interaction) described by a solvable linearized Boltzman equation with thermaljzation on unifopmly distributed scatterers. It is shown that jf one scales the time t, the reciprocal space coordinate k vector and the Debye length l as lambda 2 t, k vector/lambda, lambda l respectively, in the lambda→infinity limit the charge density is equal to the solution of the corresponding diffusion-conduction (macroscopic) equation. (author)

  20. Scanner-based macroscopic color variation estimation

    Science.gov (United States)

    Kuo, Chunghui; Lai, Di; Zeise, Eric

    2006-01-01

    Flatbed scanners have been adopted successfully in the measurement of microscopic image artifacts, such as granularity and mottle, in print samples because of their capability of providing full color, high resolution images. Accurate macroscopic color measurement relies on the use of colorimeters or spectrophotometers to provide a surrogate for human vision. The very different color response characteristics of flatbed scanners from any standard colorimetric response limits the utility of a flatbed scanner as a macroscopic color measuring device. This metamerism constraint can be significantly relaxed if our objective is mainly to quantify the color variations within a printed page or between pages where a small bias in measured colors can be tolerated as long as the color distributions relative to the individual mean values is similar. Two scenarios when converting color from the device RGB color space to a standardized color space such as CIELab are studied in this paper, blind and semi-blind color transformation, depending on the availability of the black channel information. We will show that both approaches offer satisfactory results in quantifying macroscopic color variation across pages while the semi-blind color transformation further provides fairly accurate color prediction capability.

  1. Quantum teleportation from light beams to vibrational states of a macroscopic diamond

    Science.gov (United States)

    Hou, P.-Y.; Huang, Y.-Y.; Yuan, X.-X.; Chang, X.-Y.; Zu, C.; He, L.; Duan, L.-M.

    2016-01-01

    With the recent development of optomechanics, the vibration in solids, involving collective motion of trillions of atoms, gradually enters into the realm of quantum control. Here, building on the recent remarkable progress in optical control of motional states of diamonds, we report an experimental demonstration of quantum teleportation from light beams to vibrational states of a macroscopic diamond under ambient conditions. Through quantum process tomography, we demonstrate average teleportation fidelity (90.6±1.0)%, clearly exceeding the classical limit of 2/3. The experiment pushes the target of quantum teleportation to the biggest object so far, with interesting implications for optomechanical quantum control and quantum information science. PMID:27240553

  2. Influence of plasma pressure gradient on melt layer macroscopic erosion of metal targets in disruption simulation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Tereshin, V.I.; Garkusha, I.E. E-mail: garkusha@ipp.kharkov.ua; Bandura, A.N.; Byrka, O.V.; Chebotarev, V.V.; Makhlaj, V.A.; Solyakov, D.G.; Wuerz, H

    2003-03-01

    Melt layer erosion of metal targets under pulsed high heat loads is discussed. Tungsten, copper, aluminum, and titanium targets were exposed to perpendicular and inclined plasma impact in the quasi-steady-state plasma accelerator QSPA Kh-50. Melt layer motion results in erosion crater formation with rather large mountains of the resolidified material at the crater edge. It is shown that macroscopic motion of the melt layer and surface cracking are the main factors responsible for tungsten erosion.

  3. Influence of plasma pressure gradient on melt layer macroscopic erosion of metal targets in disruption simulation experiments

    International Nuclear Information System (INIS)

    Tereshin, V.I.; Garkusha, I.E.; Bandura, A.N.; Byrka, O.V.; Chebotarev, V.V.; Makhlaj, V.A.; Solyakov, D.G.; Wuerz, H.

    2003-01-01

    Melt layer erosion of metal targets under pulsed high heat loads is discussed. Tungsten, copper, aluminum, and titanium targets were exposed to perpendicular and inclined plasma impact in the quasi-steady-state plasma accelerator QSPA Kh-50. Melt layer motion results in erosion crater formation with rather large mountains of the resolidified material at the crater edge. It is shown that macroscopic motion of the melt layer and surface cracking are the main factors responsible for tungsten erosion

  4. Efficacy of combined local mechanical vibrations, continuous passive motion and thermotherapy in the management of osteoarthritis of the knee.

    Science.gov (United States)

    Kitay, G S; Koren, M J; Helfet, D L; Parides, M K; Markenson, J A

    2009-10-01

    We evaluated the efficacy of combined mechanical vibrations, continuous passive motion (CPM) and heat on the severity of pain in management of osteoarthritis of the knee (OA-K). In this controlled, double crossover study, 71 OA-K patients were randomized in Phase 1 to receive 4 weeks active treatment consisting of two 20-min sessions per day (34 patients, Group AB) or treatment with a sham device (37 patients, Group BA). This was followed by a 2-week washout period (Phase 2). In Phase 3, patients crossed over so that Group AB was treated with the sham device and Group BA received active treatment for an additional 4 weeks. Patient assessments of pain (visual analog scale, VAS) and Western Ontario and McMaster Universities (WOMAC) OA index were performed at baseline and at study weeks 2, 4, 6, and 10. Net treatment effects were estimated by comparing outcomes between active and sham treatment study phases. Treatment benefits were noted for both of the trial's two pre-specified primary endpoints, VAS and WOMAC. VAS was reduced at all follow-up time points for patients receiving active treatment compared to sham treatment with a net treatment effect of 14.4+/-4.1 mm (P=0.001). Similarly, the WOMAC score was reduced significantly with active treatment at all measured points with a net effect of 8.8+/-1.9 points (Ppain, improves ROM and the quality of life in patients with OA-K (ClinicalTrials.gov registration number: NCT00858416).

  5. Relationship between the mechanisms of gamma rhythm generation and the magnitude of the macroscopic phase response function in a population of excitatory and inhibitory modified quadratic integrate-and-fire neurons

    Science.gov (United States)

    Akao, Akihiko; Ogawa, Yutaro; Jimbo, Yasuhiko; Ermentrout, G. Bard; Kotani, Kiyoshi

    2018-01-01

    Gamma oscillations are thought to play an important role in brain function. Interneuron gamma (ING) and pyramidal interneuron gamma (PING) mechanisms have been proposed as generation mechanisms for these oscillations. However, the relation between the generation mechanisms and the dynamical properties of the gamma oscillation are still unclear. Among the dynamical properties of the gamma oscillation, the phase response function (PRF) is important because it encodes the response of the oscillation to inputs. Recently, the PRF for an inhibitory population of modified theta neurons that generate an ING rhythm was computed by the adjoint method applied to the associated Fokker-Planck equation (FPE) for the model. The modified theta model incorporates conductance-based synapses as well as the voltage and current dynamics. Here, we extended this previous work by creating an excitatory-inhibitory (E-I) network using the modified theta model and described the population dynamics with the corresponding FPE. We conducted a bifurcation analysis of the FPE to find parameter regions which generate gamma oscillations. In order to label the oscillatory parameter regions by their generation mechanisms, we defined ING- and PING-type gamma oscillation in a mathematically plausible way based on the driver of the inhibitory population. We labeled the oscillatory parameter regions by these generation mechanisms and derived PRFs via the adjoint method on the FPE in order to investigate the differences in the responses of each type of oscillation to inputs. PRFs for PING and ING mechanisms are derived and compared. We found the amplitude of the PRF for the excitatory population is larger in the PING case than in the ING case. Finally, the E-I population of the modified theta neuron enabled us to analyze the PRFs of PING-type gamma oscillation and the entrainment ability of E and I populations. We found a parameter region in which PRFs of E and I are both purely positive in the case of

  6. Estimating minimum polycrystalline aggregate size for macroscopic material homogeneity

    International Nuclear Information System (INIS)

    Kovac, M.; Simonovski, I.; Cizelj, L.

    2002-01-01

    During severe accidents the pressure boundary of reactor coolant system can be subjected to extreme loadings, which might cause failure. Reliable estimation of the extreme deformations can be crucial to determine the consequences of severe accidents. Important drawback of classical continuum mechanics is idealization of inhomogenous microstructure of materials. Classical continuum mechanics therefore cannot predict accurately the differences between measured responses of specimens, which are different in size but geometrical similar (size effect). A numerical approach, which models elastic-plastic behavior on mesoscopic level, is proposed to estimate minimum size of polycrystalline aggregate above which it can be considered macroscopically homogeneous. The main idea is to divide continuum into a set of sub-continua. Analysis of macroscopic element is divided into modeling the random grain structure (using Voronoi tessellation and random orientation of crystal lattice) and calculation of strain/stress field. Finite element method is used to obtain numerical solutions of strain and stress fields. The analysis is limited to 2D models.(author)

  7. Knee joint contact mechanics during downhill gait and its relationship with varus/valgus motion and muscle strength in patients with knee osteoarthritis.

    Science.gov (United States)

    Farrokhi, Shawn; Voycheck, Carrie A; Gustafson, Jonathan A; Fitzgerald, G Kelley; Tashman, Scott

    2016-01-01

    The objective of this exploratory study was to evaluate tibiofemoral joint contact point excursions and velocities during downhill gait and assess the relationship between tibiofemoral joint contact mechanics with frontal-plane knee joint motion and lower extremity muscle weakness in patients with knee osteoarthritis (OA). Dynamic stereo X-ray was used to quantify tibiofemoral joint contact mechanics and frontal-plane motion during the loading response phase of downhill gait in 11 patients with knee OA and 11 control volunteers. Quantitative testing of the quadriceps and the hip abductor muscles was also performed. Patients with knee OA demonstrated larger medial/lateral joint contact point excursions (p knee OA compared to their control counterparts (p = 0.02). Additionally, patients with knee OA demonstrated significantly increased frontal-plane varus motion excursions (p knee OA were linearly associated with greater frontal-plane varus motion excursions (p knee OA may be related to compromised frontal-plane joint stability but not with deficits in muscle strength.

  8. Fractionalization of the complex-valued Brownian motion of order n using Riemann-Liouville derivative. Applications to mathematical finance and stochastic mechanics

    International Nuclear Information System (INIS)

    Jumarie, Guy

    2006-01-01

    The (complex-valued) Brownian motion of order n is defined as the limit of a random walk on the complex roots of the unity. Real-valued fractional noises are obtained as fractional derivatives of the Gaussian white noise (or order two). Here one combines these two approaches and one considers the new class of fractional noises obtained as fractional derivative of the complex-valued Brownian motion of order n. The key of the approach is the relation between differential and fractional differential provided by the fractional Taylor's series of analytic function f(z+h)=E α (h α D z α ).f(z), where E α is the Mittag-Leffler function on the one hand, and the generalized Maruyama's notation, on the other hand. Some questions are revisited such as the definition of fractional Brownian motion as integral w.r.t. (dt) α , and the exponential growth equation driven by fractional Brownian motion, to which a new solution is proposed. As a first illustrative example of application, in mathematical finance, one proposes a new approach to the optimal management of a stochastic portfolio of fractional order via the Lagrange variational technique applied to the state moment dynamical equations. In the second example, one deals with non-random Lagrangian mechanics of fractional order. The last example proposes a new approach to fractional stochastic mechanics, and the solution so obtained gives rise to the question as to whether physical systems would not have their own internal random times

  9. Experimental demonstration of macroscopic quantum coherence in Gaussian states

    DEFF Research Database (Denmark)

    Marquardt, C.; Andersen, Ulrik Lund; Leuchs, G.

    2007-01-01

    We witness experimentally the presence of macroscopic coherence in Gaussian quantum states using a recently proposed criterion [E. G. Cavalcanti and M. D. Reid, Phys. Rev. Lett. 97 170405 (2006)]. The macroscopic coherence stems from interference between macroscopically distinct states in phase...

  10. COMPUTER SIMULATION IN MECHANICS TEACHING AND LEARNING: A CASE STUDY ON STUDENTS’ UNDERSTANDING OF FORCE AND MOTION

    Directory of Open Access Journals (Sweden)

    Dyah Permata Sari

    2015-12-01

    Full Text Available The objective of this research was to develop a force and motion simulation based on the open-source Easy Java Simulation. The process of computer simulation development was done following the ADDIE model. Based on the Analysis and Design phases, the Development phase used the open-source Easy Java Simulation (EJS to develop a computer simulation with physics content that was relevant to the subtopic. Computing and communication technology continue to make an increasing impact on all aspects of education. EJS is a powerful didactic resource that gives us the ability to focus our students’ attention on the principles of physics. Using EJS, a computer simulation was created through which the motion of a particle under the action of a specific force can be studied. The implementation phase is implemented the computer simulation in the teaching and learning process. To describe the improvements in the students’ understanding of the force and motion concepts, we used a t-test to evaluate each of the four phases. These results indicated that the use of the computer simulation could improve students’ force and motion conceptual competence regarding Newton's second law of motion.

  11. Macroscopic quantum tunneling of the magnetic moment

    Science.gov (United States)

    Tejada, J.; Hernandez, J. M.; del Barco, E.

    1999-05-01

    In this paper we review the work done on magnetic relaxation during the last 10 years on both single-domain particles and magnetic molecules and its contribution to the discovery of quantum tunneling of the magnetic moment (Chudnovsky and Tejada, Macroscopic Quantum tunneling of the Magnetic moment, Cambridge University press, Cambridge, 1998). We present first the theoretical expressions and their connection to quantum relaxation and secondly, we show and discuss the experimental results. Finally, we discuss very recent hysteresis data on Mn 12Ac molecules at extremely large sweeping rate for the external magnetic field which suggest the existence of quantum spin—phonon avalanches.

  12. Compressor Has No Moving Macroscopic Parts

    Science.gov (United States)

    Gasser, Max

    1995-01-01

    Compressor containing no moving macroscopic parts functions by alternating piston and valve actions of successive beds of magnetic particles. Fabricated easily because no need for precisely fitting parts rotating or sliding on each other. Also no need for lubricant fluid contaminating fluid to be compressed. Compressor operates continuously, eliminating troublesome on/off cycling of other compressors, and decreasing consumption of energy. Phased cells push fluid from bottom to top, adding increments of pressure. Each cell contains magnetic powder particles loose when electromagnet coil deenergized, but tightly packed when coil energized.

  13. Catalytic Growth of Macroscopic Carbon Nanofibers Bodies with Activated Carbon

    Science.gov (United States)

    Abdullah, N.; Rinaldi, A.; Muhammad, I. S.; Hamid, S. B. Abd.; Su, D. S.; Schlogl, R.

    2009-06-01

    Carbon-carbon composite of activated carbon and carbon nanofibers have been synthesized by growing Carbon nanofiber (CNF) on Palm shell-based Activated carbon (AC) with Ni catalyst. The composites are in an agglomerated shape due to the entanglement of the defective CNF between the AC particles forming a macroscopic body. The macroscopic size will allow the composite to be used as a stabile catalyst support and liquid adsorbent. The preparation of CNT/AC nanocarbon was initiated by pre-treating the activated carbon with nitric acid, followed by impregnation of 1 wt% loading of nickel (II) nitrate solutions in acetone. The catalyst precursor was calcined and reduced at 300° C for an hour in each step. The catalytic growth of nanocarbon in C2H4/H2 was carried out at temperature of 550° C for 2 hrs with different rotating angle in the fluidization system. SEM and N2 isotherms show the level of agglomeration which is a function of growth density and fluidization of the system. The effect of fluidization by rotating the reactor during growth with different speed give a significant impact on the agglomeration of the final CNF/AC composite and thus the amount of CNFs produced. The macrostructure body produced in this work of CNF/AC composite will have advantages in the adsorbent and catalyst support application, due to the mechanical and chemical properties of the material.

  14. The right frame of reference makes it simple: an example of introductory mechanics supported by video analysis of motion

    International Nuclear Information System (INIS)

    Klein, P; Gröber, S; Kuhn, J; Fleischhauer, A; Müller, A

    2015-01-01

    The selection and application of coordinate systems is an important issue in physics. However, considering different frames of references in a given problem sometimes seems un-intuitive and is difficult for students. We present a concrete problem of projectile motion which vividly demonstrates the value of considering different frames of references. We use this example to explore the effectiveness of video-based motion analysis (VBMA) as an instructional technique at university level in enhancing students’ understanding of the abstract concept of coordinate systems. A pilot study with 47 undergraduate students indicates that VBMA instruction improves conceptual understanding of this issue. (paper)

  15. The right frame of reference makes it simple: an example of introductory mechanics supported by video analysis of motion

    Science.gov (United States)

    Klein, P.; Gröber, S.; Kuhn, J.; Fleischhauer, A.; Müller, A.

    2015-01-01

    The selection and application of coordinate systems is an important issue in physics. However, considering different frames of references in a given problem sometimes seems un-intuitive and is difficult for students. We present a concrete problem of projectile motion which vividly demonstrates the value of considering different frames of references. We use this example to explore the effectiveness of video-based motion analysis (VBMA) as an instructional technique at university level in enhancing students’ understanding of the abstract concept of coordinate systems. A pilot study with 47 undergraduate students indicates that VBMA instruction improves conceptual understanding of this issue.

  16. Macroscopic quantum tunneling in Mn12-acetat

    International Nuclear Information System (INIS)

    Beiter, J.; Reissner, M.; Hilscher, G.; Steiner, W.; Pajic, D.; Zadro, K.; Bartel, M.; Linert, W.

    2004-01-01

    Molecules provide the exciting opportunity to study magnetism on the passage from atomic to macroscopic level. One of the most interesting effects in such mesoscopic systems is the appearance of quantum tunnelling of magnetization (MQT) at low temperatures. In the last decade molecular chemistry has had a large impact in this field by providing new single molecule magnets. They consist of small clusters exhibiting superparamagnetic behavior, similar to that of conventional nanomagnetic particles. The advantage of these new materials is that they form macroscopic samples consisting of regularly arranged small identical high-spin clusters which are widely separated by organic molecules. The lack of distributions in size and shape of the magnetic clusters and the very weak intercluster interaction lead in principle to only one barrier for the spin reversal. We present detailed magnetic investigations on a Mn 12 -ac single crystal. In this compound the tetragonal ordered clusters consist of a central tetrahedron of four Mn 4+ (S = 3/2) atoms surrounded by eight Mn 3+ (S = 2) atoms with antiparallel oriented spins, leading to an overall spin moment of S = 10. In the hysteresis loops nine different jumps at regularly spaced fields are identified in the investigated temperature range (1.5 < T < 3 K). At these fields the relaxation of moment due to thermal activation is superimposed by strong quantum tunnelling. In lowering the temperature the time dependence changes from thermally activated to thermally assisted tunnelling. (author)

  17. Macroscopic effects of the quantum trace anomaly

    International Nuclear Information System (INIS)

    Mottola, Emil; Vaulin, Ruslan

    2006-01-01

    The low energy effective action of gravity in any even dimension generally acquires nonlocal terms associated with the trace anomaly, generated by the quantum fluctuations of massless fields. The local auxiliary field description of this effective action in four dimensions requires two additional scalar fields, not contained in classical general relativity, which remain relevant at macroscopic distance scales. The auxiliary scalar fields depend upon boundary conditions for their complete specification, and therefore carry global information about the geometry and macroscopic quantum state of the gravitational field. The scalar potentials also provide coordinate invariant order parameters describing the conformal behavior and divergences of the stress tensor on event horizons. We compute the stress tensor due to the anomaly in terms of its auxiliary scalar potentials in a number of concrete examples, including the Rindler wedge, the Schwarzschild geometry, and de Sitter spacetime. In all of these cases, a small number of classical order parameters completely determine the divergent behaviors allowed on the horizon, and yield qualitatively correct global approximations to the renormalized expectation value of the quantum stress tensor

  18. Molecular machines with bio-inspired mechanisms.

    Science.gov (United States)

    Zhang, Liang; Marcos, Vanesa; Leigh, David A

    2018-02-26

    The widespread use of molecular-level motion in key natural processes suggests that great rewards could come from bridging the gap between the present generation of synthetic molecular machines-which by and large function as switches-and the machines of the macroscopic world, which utilize the synchronized behavior of integrated components to perform more sophisticated tasks than is possible with any individual switch. Should we try to make molecular machines of greater complexity by trying to mimic machines from the macroscopic world or instead apply unfamiliar (and no doubt have to discover or invent currently unknown) mechanisms utilized by biological machines? Here we try to answer that question by exploring some of the advances made to date using bio-inspired machine mechanisms.

  19. Study on fundamental mechanism of nuclear advanced robot. An analysis of fundamental motion with pliability for end-effector of advanced robot

    International Nuclear Information System (INIS)

    Ohki, Arahiko; Hirano, Sigeo; Yoshida, Tomoya.

    1997-01-01

    Most of present robots only perform works simulating human action, but hereafter, it is required to do advanced works smoothly with robots in place of men. Among the mechanisms of high performance robots, as one of the important components that do advanced action and adapt to diversified purposes, there is manipulator. The manipulator comprises arm and end effector. In the process of heightening robot performance hereafter, the reproduction of detailed action is the indispensable subject of research. The object of carrying out this research is to elucidate the possibility of giving the functions close to those of delicate human hands to end effector. First, the joints of human hands were measured, and based on these data, the equation for determining the change of angle in relation to the time of motion of respective joints was established. Further, the simulation of simple actions was carried out, and the concept of the mechanism model was built by analyzing the motion similar to human body. The structural difference in the joints of human and manipulator, the measurement of hands and the analysis of the motion of hand joints are reported. (K.I.)

  20. Generating macroscopic chaos in a network of globally coupled phase oscillators

    Science.gov (United States)

    So, Paul; Barreto, Ernest

    2011-01-01

    We consider an infinite network of globally coupled phase oscillators in which the natural frequencies of the oscillators are drawn from a symmetric bimodal distribution. We demonstrate that macroscopic chaos can occur in this system when the coupling strength varies periodically in time. We identify period-doubling cascades to chaos, attractor crises, and horseshoe dynamics for the macroscopic mean field. Based on recent work that clarified the bifurcation structure of the static bimodal Kuramoto system, we qualitatively describe the mechanism for the generation of such complicated behavior in the time varying case. PMID:21974662

  1. Upside/Downside statistical mechanics of nonequilibrium Brownian motion. I. Distributions, moments, and correlation functions of a free particle

    Science.gov (United States)

    Craven, Galen T.; Nitzan, Abraham

    2018-01-01

    Statistical properties of Brownian motion that arise by analyzing, separately, trajectories over which the system energy increases (upside) or decreases (downside) with respect to a threshold energy level are derived. This selective analysis is applied to examine transport properties of a nonequilibrium Brownian process that is coupled to multiple thermal sources characterized by different temperatures. Distributions, moments, and correlation functions of a free particle that occur during upside and downside events are investigated for energy activation and energy relaxation processes and also for positive and negative energy fluctuations from the average energy. The presented results are sufficiently general and can be applied without modification to the standard Brownian motion. This article focuses on the mathematical basis of this selective analysis. In subsequent articles in this series, we apply this general formalism to processes in which heat transfer between thermal reservoirs is mediated by activated rate processes that take place in a system bridging them.

  2. Estimation of macroscopic elastic characteristics for hierarchical anisotropic solids based on probabilistic approach

    Science.gov (United States)

    Smolina, Irina Yu.

    2015-10-01

    Mechanical properties of a cable are of great importance in design and strength calculation of flexible cables. The problem of determination of elastic properties and rigidity characteristics of a cable modeled by anisotropic helical elastic rod is considered. These characteristics are calculated indirectly by means of the parameters received from statistical processing of experimental data. These parameters are considered as random quantities. With taking into account probable nature of these parameters the formulas for estimation of the macroscopic elastic moduli of a cable are obtained. The calculating expressions for macroscopic flexural rigidity, shear rigidity and torsion rigidity using the macroscopic elastic characteristics obtained before are presented. Statistical estimations of the rigidity characteristics of some cable grades are adduced. A comparison with those characteristics received on the basis of deterministic approach is given.

  3. A strict experimental test of macroscopic realism in a superconducting flux qubit.

    Science.gov (United States)

    Knee, George C; Kakuyanagi, Kosuke; Yeh, Mao-Chuang; Matsuzaki, Yuichiro; Toida, Hiraku; Yamaguchi, Hiroshi; Saito, Shiro; Leggett, Anthony J; Munro, William J

    2016-11-04

    Macroscopic realism is the name for a class of modifications to quantum theory that allow macroscopic objects to be described in a measurement-independent manner, while largely preserving a fully quantum mechanical description of the microscopic world. Objective collapse theories are examples which aim to solve the quantum measurement problem through modified dynamical laws. Whether such theories describe nature, however, is not known. Here we describe and implement an experimental protocol capable of constraining theories of this class, that is more noise tolerant and conceptually transparent than the original Leggett-Garg test. We implement the protocol in a superconducting flux qubit, and rule out (by ∼84 s.d.) those theories which would deny coherent superpositions of 170 nA currents over a ∼10 ns timescale. Further, we address the 'clumsiness loophole' by determining classical disturbance with control experiments. Our results constitute strong evidence for the superposition of states of nontrivial macroscopic distinctness.

  4. Partitioning a macroscopic system into independent subsystems

    Science.gov (United States)

    Delle Site, Luigi; Ciccotti, Giovanni; Hartmann, Carsten

    2017-08-01

    We discuss the problem of partitioning a macroscopic system into a collection of independent subsystems. The partitioning of a system into replica-like subsystems is nowadays a subject of major interest in several fields of theoretical and applied physics. The thermodynamic approach currently favoured by practitioners is based on a phenomenological definition of an interface energy associated with the partition, due to a lack of easily computable expressions for a microscopic (i.e. particle-based) interface energy. In this article, we outline a general approach to derive sharp and computable bounds for the interface free energy in terms of microscopic statistical quantities. We discuss potential applications in nanothermodynamics and outline possible future directions.

  5. Quantum teleportation between stationary macroscopic objects

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Xiao-Hui; Yuan, Zhen-Sheng; Pan, Jian-Wei [Physikalisches Institut, Universitaet Heidelberg (Germany); Hefei National Laboratory for Physical Sciences at Microscale, Department of Modern Physics, University of Science and Technology of China, Hefei (China); Xu, Xiao-Fan [Physikalisches Institut, Universitaet Heidelberg (Germany); Li, Che-Ming [Physikalisches Institut, Universitaet Heidelberg (Germany); Department of Physics, National Center for Theoretical Sciences, National Cheng Kung University, Tainan (China)

    2010-07-01

    Quantum teleportation is a process to transfer a quantum state of an object without transferring the state carrier itself. So far, most of the teleportation experiments realized are within the photonic regime. For the teleportation of stationary states, the largest system reported is a single ion. We are now performing an experiment to teleport the state of an macroscopic atomic cloud which consists about 10{sup 6} single atoms. In our experiment two atomic ensembles are utilized. In the first ensemble A we prepare the collective atomic state to be teleported using the quantum feedback technique. The second ensemble B is utilized to generate entanglement between it collective state with a scattered single-photon. Teleportation is realized by converting the atomic state of A to a single-photon and making a Bell state measurement with the scattered single-photon from ensemble B.

  6. Macroscopic balance model for wave rotors

    Science.gov (United States)

    Welch, Gerard E.

    1996-01-01

    A mathematical model for multi-port wave rotors is described. The wave processes that effect energy exchange within the rotor passage are modeled using one-dimensional gas dynamics. Macroscopic mass and energy balances relate volume-averaged thermodynamic properties in the rotor passage control volume to the mass, momentum, and energy fluxes at the ports. Loss models account for entropy production in boundary layers and in separating flows caused by blade-blockage, incidence, and gradual opening and closing of rotor passages. The mathematical model provides a basis for predicting design-point wave rotor performance, port timing, and machine size. Model predictions are evaluated through comparisons with CFD calculations and three-port wave rotor experimental data. A four-port wave rotor design example is provided to demonstrate model applicability. The modeling approach is amenable to wave rotor optimization studies and rapid assessment of the trade-offs associated with integrating wave rotors into gas turbine engine systems.

  7. Reactive probing of macroscopically quantum mechanical SQUID rings

    International Nuclear Information System (INIS)

    Prance, R.J.; Clark, T.D.; Whiteman, R.; Diggins, J.; Ralph, J.F.; Prance, H.; Spiller, T.P.; Widom, A.; Srivastava, Y.

    1994-01-01

    In this paper we demonstrate that the energy level structure of ultra small capacitance SQUID rings can be probed adiabatically at radio frequency using both dynamical and quasistatic reactive techniques. ((orig.))

  8. Sharpened cortical tuning and enhanced cortico-cortical communication contribute to the long-term neural mechanisms of visual motion perceptual learning.

    Science.gov (United States)

    Chen, Nihong; Bi, Taiyong; Zhou, Tiangang; Li, Sheng; Liu, Zili; Fang, Fang

    2015-07-15

    Much has been debated about whether the neural plasticity mediating perceptual learning takes place at the sensory or decision-making stage in the brain. To investigate this, we trained human subjects in a visual motion direction discrimination task. Behavioral performance and BOLD signals were measured before, immediately after, and two weeks after training. Parallel to subjects' long-lasting behavioral improvement, the neural selectivity in V3A and the effective connectivity from V3A to IPS (intraparietal sulcus, a motion decision-making area) exhibited a persistent increase for the trained direction. Moreover, the improvement was well explained by a linear combination of the selectivity and connectivity increases. These findings suggest that the long-term neural mechanisms of motion perceptual learning are implemented by sharpening cortical tuning to trained stimuli at the sensory processing stage, as well as by optimizing the connections between sensory and decision-making areas in the brain. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Distinct molecular features of different macroscopic subtypes of colorectal neoplasms.

    Directory of Open Access Journals (Sweden)

    Kenichi Konda

    Full Text Available Colorectal adenoma develops into cancer with the accumulation of genetic and epigenetic changes. We studied the underlying molecular and clinicopathological features to better understand the heterogeneity of colorectal neoplasms (CRNs.We evaluated both genetic (mutations of KRAS, BRAF, TP53, and PIK3CA, and microsatellite instability [MSI] and epigenetic (methylation status of nine genes or sequences, including the CpG island methylator phenotype [CIMP] markers alterations in 158 CRNs including 56 polypoid neoplasms (PNs, 25 granular type laterally spreading tumors (LST-Gs, 48 non-granular type LSTs (LST-NGs, 19 depressed neoplasms (DNs and 10 small flat-elevated neoplasms (S-FNs on the basis of macroscopic appearance.S-FNs showed few molecular changes except SFRP1 methylation. Significant differences in the frequency of KRAS mutations were observed among subtypes (68% for LST-Gs, 36% for PNs, 16% for DNs and 6% for LST-NGs (P<0.001. By contrast, the frequency of TP53 mutation was higher in DNs than PNs or LST-Gs (32% vs. 5% or 0%, respectively (P<0.007. We also observed significant differences in the frequency of CIMP between LST-Gs and LST-NGs or PNs (32% vs. 6% or 5%, respectively (P<0.005. Moreover, the methylation level of LINE-1 was significantly lower in DNs or LST-Gs than in PNs (58.3% or 60.5% vs. 63.2%, P<0.05. PIK3CA mutations were detected only in LSTs. Finally, multivariate analyses showed that macroscopic morphologies were significantly associated with an increased risk of molecular changes (PN or LST-G for KRAS mutation, odds ratio [OR] 9.11; LST-NG or DN for TP53 mutation, OR 5.30; LST-G for PIK3CA mutation, OR 26.53; LST-G or DN for LINE-1 hypomethylation, OR 3.41.We demonstrated that CRNs could be classified into five macroscopic subtypes according to clinicopathological and molecular differences, suggesting that different mechanisms are involved in the pathogenesis of colorectal tumorigenesis.

  10. Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

    International Nuclear Information System (INIS)

    Cleland, A.N.

    1991-04-01

    Experiments investigating the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very small capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters; the tunneling rate in the moderately damped (Q ∼ 1) junction is seen to be reduced by a factor of 300 from that predicted for an undamped junction. The phase is seen to be a good quantum-mechanical variable. The experiments on small capacitance tunnel junctions extend the measurements on the larger-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wavefunction has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias. I present the first clear observation of the Coulomb blockade in single junctions. The electrical environment of the tunnel junction, however, strongly affects the behavior of the junction: higher resistance leads are observed to greatly sharpen the Coulomb blockade over that seen with lower resistance leads. I present theoretical descriptions of how the environment influences the junctions; comparisons with the experimental results are in reasonable agreement

  11. Sideband cooling of micromechanical motion to the quantum ground state.

    Science.gov (United States)

    Teufel, J D; Donner, T; Li, Dale; Harlow, J W; Allman, M S; Cicak, K; Sirois, A J; Whittaker, J D; Lehnert, K W; Simmonds, R W

    2011-07-06

    The advent of laser cooling techniques revolutionized the study of many atomic-scale systems, fuelling progress towards quantum computing with trapped ions and generating new states of matter with Bose-Einstein condensates. Analogous cooling techniques can provide a general and flexible method of preparing macroscopic objects in their motional ground state. Cavity optomechanical or electromechanical systems achieve sideband cooling through the strong interaction between light and motion. However, entering the quantum regime--in which a system has less than a single quantum of motion--has been difficult because sideband cooling has not sufficiently overwhelmed the coupling of low-frequency mechanical systems to their hot environments. Here we demonstrate sideband cooling of an approximately 10-MHz micromechanical oscillator to the quantum ground state. This achievement required a large electromechanical interaction, which was obtained by embedding a micromechanical membrane into a superconducting microwave resonant circuit. To verify the cooling of the membrane motion to a phonon occupation of 0.34 ± 0.05 phonons, we perform a near-Heisenberg-limited position measurement within (5.1 ± 0.4)h/2π, where h is Planck's constant. Furthermore, our device exhibits strong coupling, allowing coherent exchange of microwave photons and mechanical phonons. Simultaneously achieving strong coupling, ground state preparation and efficient measurement sets the stage for rapid advances in the control and detection of non-classical states of motion, possibly even testing quantum theory itself in the unexplored region of larger size and mass. Because mechanical oscillators can couple to light of any frequency, they could also serve as a unique intermediary for transferring quantum information between microwave and optical domains.

  12. Displaced rocks, strong motion, and the mechanics of shallow faulting associated with the 1999 Hector Mine, California, earthquake

    Science.gov (United States)

    Michael, Andrew J.; Ross, Stephanie L.; Stenner, Heidi D.

    2002-01-01

    The paucity of strong-motion stations near the 1999 Hector Mine earthquake makes it impossible to make instrumental studies of key questions about near-fault strong-motion patterns associated with this event. However, observations of displaced rocks allow a qualitative investigation of these problems. By observing the slope of the desert surface and the frictional coefficient between these rocks and the desert surface, we estimate the minimum horizontal acceleration needed to displace the rocks. Combining this information with observations of how many rocks were displaced in different areas near the fault, we infer the level of shaking. Given current empirical shaking attenuation relationships, the number of rocks that moved is slightly lower than expected; this implies that slightly lower than expected shaking occurred during the Hector Mine earthquake. Perhaps more importantly, stretches of the fault with 4 m of total displacement at the surface displaced few nearby rocks on 15?? slopes, suggesting that the horizontal accelerations were below 0.2g within meters of the fault scarp. This low level of shaking suggests that the shallow parts of this rupture did not produce strong accelerations. Finally, we did not observe an increased incidence of displaced rocks along the fault zone itself. This suggests that, despite observations of fault-zone-trapped waves generated by aftershocks of the Hector Mine earthquake, such waves were not an important factor in controlling peak ground acceleration during the mainshock.

  13. Macroscopic Magnetization Control by Symmetry Breaking of Photoinduced Spin Reorientation with Intense Terahertz Magnetic Near Field

    Science.gov (United States)

    Kurihara, Takayuki; Watanabe, Hiroshi; Nakajima, Makoto; Karube, Shutaro; Oto, Kenichi; Otani, YoshiChika; Suemoto, Tohru

    2018-03-01

    We exploit an intense terahertz magnetic near field combined with femtosecond laser excitation to break the symmetry of photoinduced spin reorientation paths in ErFeO3 . We succeed in aligning macroscopic magnetization reaching up to 80% of total magnetization in the sample to selectable orientations by adjusting the time delay between terahertz and optical pump pulses. The spin dynamics are well reproduced by equations of motion, including time-dependent magnetic potential. We show that the direction of the generated magnetization is determined by the transient direction of spin tilting and the magnetic field at the moment of photoexcitation.

  14. Searching for the nanoscopic–macroscopic boundary

    Energy Technology Data Exchange (ETDEWEB)

    Velásquez, E.A. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Grupo de Investigación en Modelamiento y Simulación Computacional, Universidad de San Buenaventura Sec. Medellín, A.A. 5222, Medellín (Colombia); Altbir, D. [Departamento de Física, Universidad de Santiago de Chile (USACH), CEDENNA, Santiago (Chile); Mazo-Zuluaga, J. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Duque, L.F. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Grupo de Física Teórica, Aplicada y Didáctica, Facultad de Ciencias Exactas y Aplicadas Instituto Tecnológico Metropolitano, Medellín (Colombia); Mejía-López, J., E-mail: jmejia@puc.cl [Facultad de Física, Pontificia Universidad Católica de Chile, CEDENNA, Santiago (Chile)

    2013-12-15

    Several studies have focused on the size-dependent properties of elements, looking for a unique definition of the nanoscopic–macroscopic boundary. By using a novel approach consisting of an energy variational method combined with a quantum Heisenberg model, here we address the size at which the ordering temperature of a magnetic nanoparticle reaches its bulk value. We consider samples with sizes in the range 1–500 nm, as well as several geometries and crystalline lattices and observe that, contrarily to what is commonly argued, the nanoscopic-microscopic boundary depends on both factors: shape and crystalline structure. This suggests that the surface-to-volume ratio is not the unique parameter that defines the behavior of a nanometric sample whenever its size increases reaching the bulk dimension. Comparisons reveal very good agreement with experimental evidence with differences less than 2%. Our results have broad implications for practical issues in measurements on systems at the nanometric scale. - Highlights: • A novel quantum-Heisenberg variational energy method is implemented. • The asymptotic behavior toward the thermodynamic limit is explored. • An important dependence of the nano-bulk boundary on the geometry is found. • And also an important dependence on the crystalline lattice. • We obtain a very good agreement with experimental evidence with differences <2%.

  15. Adiabatic process reversibility: microscopic and macroscopic views

    International Nuclear Information System (INIS)

    Anacleto, Joaquim; Pereira, Mario G

    2009-01-01

    The reversibility of adiabatic processes was recently addressed by two publications. In the first (Miranda 2008 Eur. J. Phys. 29 937-43), an equation was derived relating the initial and final volumes and temperatures for adiabatic expansions of an ideal gas, using a microscopic approach. In that relation the parameter r accounts for the process reversibility, ranging between 0 and 1, which corresponds to the free and reversible expansion, respectively. In the second (Anacleto and Pereira 2009 Eur. J. Phys. 30 177-83), the authors have shown that thermodynamics can effectively and efficiently be used to obtain the general law for adiabatic processes carried out by an ideal gas, including compressions, for which r≥1. The present work integrates and extends the aforementioned studies, providing thus further insights into the analysis of the adiabatic process. It is shown that Miranda's work is wholly valid for compressions. In addition, it is demonstrated that the adiabatic reversibility coefficient given in terms of the piston velocity and the root mean square velocity of the gas particles is equivalent to the macroscopic description, given just by the quotient between surroundings and system pressure values. (letters and comments)

  16. Classical behaviour of macroscopic bodies and quantum measurements

    International Nuclear Information System (INIS)

    Ghirardi, G.; Rimini, A.; Weber, T.

    1986-01-01

    This report describes a recent attempt of giving a consistent and unified description of microscopic and macroscopic phenomena. The model presented in this paper exhibits the nice features of leaving unaltered the quantum description of microsystems and of accounting for the classical behaviour of the macroscopic objects when their dynamical evolution is consistently deduced from the dynamics of their elementary constituents

  17. A numerical analysis on the curved bileaflet Mechanical Heart Valve (MHV) : leaflet motion and blood flow in an elastic blood vessel

    International Nuclear Information System (INIS)

    Bang, Jin Seok; Kim, Chang Nyung; Choi, Choeng Ryul

    2005-01-01

    In blood flow passing through the Mechanical Heart Valve (MHV) and elastic blood vessel, hemolysis and platelet activation causing thrombus formation can be seen owing to the shear stress in the blood. Also, fracture and deformation of leaflets can be observed depending on the shape and material properties of the leaflets which is opened and closed in a cycle. Hence, comprehensive study is needed on the hemodynamics which is associated with the motion of leaflet and elastic blood vessel in terms of fluid-structure interaction. In this paper, a numerical analysis has been performed for a three-dimensional pulsatile blood flow associated with the elastic blood vessel and curved bileaflet for multiple cycles in light of fluid-structure interaction. From this analysis fluttering phenomenon and rebound of the leaflet have been observed and recirculation and regurgitation have been found in the flow fields of the blood. Also, the pressure distribution and the radial displacement of the elastic blood vessel have been obtained. The motion of the leaflet and flow fields of the blood have shown similar tendency compared with the previous experiments carried out in other studies. The present study can contribute to the design methodology for the curved bileaflet mechanical heart valve. Furthermore, the proposed fluid-structure interaction method will be effectively used in various fields where the interaction between fluid flow and structure are involved

  18. A practical application of the geometrical theory on fibered manifolds to an autonomous bicycle motion in mechanical system with nonholonomic constraints

    Science.gov (United States)

    Haddout, Soufiane

    2018-01-01

    The equations of motion of a bicycle are highly nonlinear and rolling of wheels without slipping can only be expressed by nonholonomic constraint equations. A geometrical theory of general nonholonomic constrained systems on fibered manifolds and their jet prolongations, based on so-called Chetaev-type constraint forces, was proposed and developed in the last decade by O. Krupková (Rossi) in 1990's. Her approach is suitable for study of all kinds of mechanical systems-without restricting to Lagrangian, time-independent, or regular ones, and is applicable to arbitrary constraints (holonomic, semiholonomic, linear, nonlinear or general nonholonomic). The goal of this paper is to apply Krupková's geometric theory of nonholonomic mechanical systems to study a concrete problem in nonlinear nonholonomic dynamics, i.e., autonomous bicycle. The dynamical model is preserved in simulations in its original nonlinear form without any simplifying. The results of numerical solutions of constrained equations of motion, derived within the theory, are in good agreement with measurements and thus they open the possibility of direct application of the theory to practical situations.

  19. Macroscopic dynamics of thermal nuclear excitations

    International Nuclear Information System (INIS)

    Bastrukov, S.I.; Deak, F.; Kiss, A.; Seres, Z.

    1989-11-01

    The concept of kinetic temperature as a local dynamical variable of thermal nuclear collective motion is formulated using long-mean-free-path approach based on the Landau-Vlasov kinetic equation. In the Fermi drop model the thermal fluid dynamics of the spherical nucleus is analyzed. It is shown that in a compressible Fermi liquid the temperature pulses propagate in the form of spherical wave in phase with the acoustic wave. The thermal and compressional excitations are caused by the isotropic harmonic oscillations of the Fermi sphere in momentum space. (author) 25 refs.; 2 figs

  20. Method and an apparatus to control the lateral motion of a long metal bar being formed by a mechanical process such as rolling or drawing

    Science.gov (United States)

    Chang, Tzyy-Shuh; Huang, Hsun-Hau; Lin, Chang-Hung

    2007-10-02

    An adjustable guide, includes two or more mechanisms each having a rotatable retaining element containing a retaining groove with a variable radius in its perimeter surface. The grooves form a guidance path to control the lateral, i.e. non-axial, motion of a long bar moving along a longitudinal axis during a production process.The diameter of the guidance path varies according to the variable radii of the grooves. The guidance path increases in size at a predetermined rate, from a point of origin to an end point on the retaining groove. Rotating the retaining elements causes the diameter of the retaining grooves to change so that the size of the guidance path can be changed to match the diameter of the bar being rolled, size of the guidance path can be changed to fit the diameter of a new bar rolled without having to exchange the guide for a different sized guide, reduce fiction between the bar and the guide, a media, such as compressed air, can be injected between the retaining elements via orifices.Each retaining element is attached to a mounting apparatus. The mounting apparatus can be fixed or flexible. The flexible mounting apparatus includes one or more springs and one or more shock absorbers. A force neutral position of the flexible mounting apparatus is designed to be located on the predetermined ideal bar path line. The flexible mounting apparatus dissipates kinetic energy from the bar thereby reducing the bar's lateral motion relative to the ideal bar path line.The damping ratio of the mounting apparatus can be adjustable to alter the product's vibration mode to enable better control of the bar's lateral motion.

  1. Proton irradiation effects on beryllium – A macroscopic assessment

    Energy Technology Data Exchange (ETDEWEB)

    Simos, Nikolaos, E-mail: simos@bnl.gov [Nuclear Sciences & Technology Department, Brookhaven National Laboratory, Upton, NY, 11973 (United States); Elbakhshwan, Mohamed [Nuclear Sciences & Technology Department, Brookhaven National Laboratory, Upton, NY, 11973 (United States); Zhong, Zhong [Photon Sciences, NSLS II, Brookhaven National Laboratory, Upton, NY, 11973 (United States); Camino, Fernando [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973 (United States)

    2016-10-15

    Beryllium, due to its excellent neutron multiplication and moderation properties, in conjunction with its good thermal properties, is under consideration for use as plasma facing material in fusion reactors and as a very effective neutron reflector in fission reactors. While it is characterized by unique combination of structural, chemical, atomic number, and neutron absorption cross section it suffers, however, from irradiation generated transmutation gases such as helium and tritium which exhibit low solubility leading to supersaturation of the Be matrix and tend to precipitate into bubbles that coalesce and induce swelling and embrittlement thus degrading the metal and limiting its lifetime. Utilization of beryllium as a pion production low-Z target in high power proton accelerators has been sought both for its low Z and good thermal properties in an effort to mitigate thermos-mechanical shock that is expected to be induced under the multi-MW power demand. To assess irradiation-induced changes in the thermal and mechanical properties of Beryllium, a study focusing on proton irradiation damage effects has been undertaken using 200 MeV protons from the Brookhaven National Laboratory Linac and followed by a multi-faceted post-irradiation analysis that included the thermal and volumetric stability of irradiated beryllium, the stress-strain behavior and its ductility loss as a function of proton fluence and the effects of proton irradiation on the microstructure using synchrotron X-ray diffraction. The mimicking of high temperature irradiation of Beryllium via high temperature annealing schemes has been conducted as part of the post-irradiation study. This paper focuses on the thermal stability and mechanical property changes of the proton irradiated beryllium and presents results of the macroscopic property changes of Beryllium deduced from thermal and mechanical tests.

  2. Quantum opto-mechanics with micromirrors : combining nano-mechanics with quantum optics

    International Nuclear Information System (INIS)

    Groeblacher, S.

    2010-01-01

    This work describes more than four years of research on the effects of the radiation-pressure force of light on macroscopic mechanical structures. The basic system studied here is a mechanical oscillator that is highly reflective and part of an optical resonator. It interacts with the optical cavity mode via the radiation-pressure force. Both the dynamics of the mechanical oscillation and the properties of the light field are modified through this interaction. In our experiments we use quantum optical tools (such as homodyning and down-conversion) with the goal of ultimately showing quantum behavior of the mechanical center of mass motion. In this thesis we present several experiments that pave the way towards this goal and when combined should allow the demonstration of the envisioned quantum phenomena, including entanglement, teleportation and Schroeodinger cat states. The study of quantum behavior of truly macroscopic systems is a long outstanding goal, which will help to answer some of the most fundamental questions in quantum physics today: Why is the world around us classical and not quantum? Is there a size- or mass-limit to systems for them to behave according to quantum mechanics? Is quantum theory complete or do we have to extend it to include mechanisms such as decoherence? Can we use the quantum nature of macroscopic objects to, for example, improve the measurement precision of classical apparatuses? The experiments discussed in this thesis include the very first passive radiation-pressure cooling of a mechanical oscillator in a cryogenic optical resonator, as well as the experimental demonstration of radiation-pressure cooling close to the mechanical quantum ground state. Cooling of the mechanical motion is an important pre-condition for observing quantum effects of the mechanical oscillator. In another experiment, we have demonstrated that we are able to enter the strong-coupling regime of the optomechanical system a regime where coherent energy

  3. Thermal activation and macroscopic quantum tunneling in a DC SQUID

    International Nuclear Information System (INIS)

    Sharifi, F.; Gavilano, J.L.; VanHarlingen, D.J.

    1989-01-01

    The authors report measurements of the transition rate from metastable minima in the two-dimensional 1 of a dc SQUID as a function of applied flux temperature. The authors observe a crossover from energy-activated escape to macroscopic quantum tunneling at a critical temperature. The macroscopic quantum tunneling rate is substantially reduced by damping, and also broadens the crossover region. Most interestingly, the authors observe thermal rates that are suppressed from those predicted by the two-dimensional thermal activation model. The authors discuss possible explanations for this based on the interaction of the macroscopic degree of freedom in the device and energy level effects

  4. Equilibrium and Macroscopic Stability of Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Lackner, K; Guenter, S; Lauber, P; Pautasso, G; Scott, B D [Max-Planck-Institut fuer Plasmaphysik IPP, Garching bei Muenchen (Germany)

    2012-09-15

    A homogenous magnetic field forces particles onto circular orbits perpendicular to it, but does not limit motion along the field lines. Inhomogeneities in the magnetic field B-vector introduce the drifts and give rise to the mirror force discussed in the previous chapter. To reduce contact between a thermonuclear grade plasma, with temperatures in the 10{sup 7} K range, with the walls, we can follow two possible strategies: either to limit field lines to closed surfaces, or to increase Vertical bar B-vector vertical bar along field lines before wall contact, so as to reflect a sufficient fraction of the energetic particles. In both cases, the magnetic fields will be inhomogeneous, and we will have to worry also about losses due to the drift of particles. (author)

  5. Discovery of a new motion mechanism of biomotors similar to the earth revolving around the sun without rotation.

    Science.gov (United States)

    Guo, Peixuan; Schwartz, Chad; Haak, Jeannie; Zhao, Zhengyi

    2013-11-01

    Biomotors have been classified into linear and rotational motors. For 35 years, it has been popularly believed that viral dsDNA-packaging apparatuses are pentameric rotation motors. Recently, a third class of hexameric motor has been found in bacteriophage phi29 that utilizes a mechanism of revolution without rotation, friction, coiling, or torque. This review addresses how packaging motors control dsDNA one-way traffic; how four electropositive layers in the channel interact with the electronegative phosphate backbone to generate four steps in translocating one dsDNA helix; how motors resolve the mismatch between 10.5 bases and 12 connector subunits per cycle of revolution; and how ATP regulates sequential action of motor ATPase. Since motors with all number of subunits can utilize the revolution mechanism, this finding helps resolve puzzles and debates concerning the oligomeric nature of packaging motors in many phage systems. This revolution mechanism helps to solve the undesirable dsDNA supercoiling issue involved in rotation. © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  6. A low-frequency wave motion mechanism enables efficient energy transport in carbon nanotubes at high heat fluxes.

    Science.gov (United States)

    Zhang, Xiaoliang; Hu, Ming; Poulikakos, Dimos

    2012-07-11

    The great majority of investigations of thermal transport in carbon nanotubes (CNTs) in the open literature focus on low heat fluxes, that is, in the regime of validity of the Fourier heat conduction law. In this paper, by performing nonequilibrium molecular dynamics simulations we investigated thermal transport in a single-walled CNT bridging two Si slabs under constant high heat flux. An anomalous wave-like kinetic energy profile was observed, and a previously unexplored, wave-dominated energy transport mechanism is identified for high heat fluxes in CNTs, originated from excited low frequency transverse acoustic waves. The transported energy, in terms of a one-dimensional low frequency mechanical wave, is quantified as a function of the total heat flux applied and is compared to the energy transported by traditional Fourier heat conduction. The results show that the low frequency wave actually overtakes traditional Fourier heat conduction and efficiently transports the energy at high heat flux. Our findings reveal an important new mechanism for high heat flux energy transport in low-dimensional nanostructures, such as one-dimensional (1-D) nanotubes and nanowires, which could be very relevant to high heat flux dissipation such as in micro/nanoelectronics applications.

  7. Macroscopic proof of the Jarzynski–Wójcik fluctuation theorem for heat exchange

    International Nuclear Information System (INIS)

    Sughiyama, Yuki; Abe, Sumiyoshi

    2008-01-01

    In a recent work, Jarzynski and Wójcik (2004 Phys. Rev. Lett. 92 230602) have shown by using the properties of Hamiltonian dynamics and a statistical mechanical consideration that heat exchange through contact between two systems initially prepared at different temperatures obeys a fluctuation theorem. Here, another proof is presented, in which only macroscopic thermodynamic quantities are employed. The detailed balance condition is found to play an essential role. As a result, the theorem is found to hold under very general conditions

  8. Quantum description of microscopic and macroscopic systems: Old problems and recent investigations

    International Nuclear Information System (INIS)

    Ghirardi, G.C.

    1986-04-01

    We review some open problems and some proposed solutions which are encountered in the quantum description of the microscopic systems, of the macroscopic ones, and of the interactions between these two types of objects. We describe a recent attempt allowing a unified description of all phenomena, reproducing the quantum mechanical situation for microscopic systems and inducing in a completely consistent way the classical behaviour of macro object and the phenomena of wave packet reduction in the system-apparatus interaction. (author)

  9. Alpha motion based on a motion detector, but not on the Müller-Lyer illusion

    Science.gov (United States)

    Suzuki, Masahiro

    2014-07-01

    This study examined the mechanism of alpha motion, the apparent motion of the Müller-Lyer figure's shaft that occurs when the arrowheads and arrow tails are alternately presented. The following facts were found: (a) reduced exposure duration decreased the amount of alpha motion, and this phenomenon was not explainable by the amount of the Müller-Lyer illusion; (b) the motion aftereffect occurred after adaptation to alpha motion; (c) occurrence of alpha motion became difficult when the temporal frequency increased, and this characteristic of alpha motion was similar to the characteristic of a motion detector that motion detection became difficult when the temporal frequency increased from the optimal frequency. These findings indicated that alpha motion occurs on the basis of a motion detector but not on the Müller-Lyer illusion, and that the mechanism of alpha motion is the same as that of general motion perception.

  10. Gravitational wave echoes from macroscopic quantum gravity effects

    Energy Technology Data Exchange (ETDEWEB)

    Barceló, Carlos [Instituto de Astrofísica de Andalucía (IAA-CSIC),Glorieta de la Astronomía, 18008 Granada (Spain); Carballo-Rubio, Raúl [The Cosmology & Gravity Group and the Laboratory for Quantum Gravity & Strings,Department of Mathematics & Applied Mathematics, University of Cape Town,Private Bag, Rondebosch 7701 (South Africa); Garay, Luis J. [Departamento de Física Teórica II,Universidad Complutense de Madrid, 28040 Madrid (Spain); Instituto de Estructura de la Materia (IEM-CSIC),Serrano 121, 28006 Madrid (Spain)

    2017-05-10

    New theoretical approaches developed in the last years predict that macroscopic quantum gravity effects in black holes should lead to modifications of the gravitational wave signals expected in the framework of classical general relativity, with these modifications being characterized in certain scenarios by the existence of dampened repetitions of the primary signal. Here we use the fact that non-perturbative corrections to the near-horizon external geometry of black holes are necessary for these modifications to exist, in order to classify different proposals and paradigms with respect to this criterion and study in a neat and systematic way their phenomenology. Proposals that lead naturally to the existence of echoes in the late-time ringdown of gravitational wave signals from black hole mergers must share the replacement of black holes by horizonless configurations with a physical surface showing reflective properties in the relevant range of frequencies. On the other hand, proposals or paradigms that restrict quantum gravity effects on the external geometry to be perturbative, such as black hole complementarity or the closely related firewall proposal, do not display echoes. For the sake of completeness we exploit the interplay between the timescales associated with the formation of firewalls and the mechanism behind the existence of echoes in order to conclude that even unconventional distortions of the firewall concept (such as naked firewalls) do not lead to this phenomenon.

  11. Zero time tunneling: macroscopic experiments with virtual particles

    Directory of Open Access Journals (Sweden)

    Nimtz Günter

    2015-01-01

    Full Text Available Feynman introduced virtual particles in his diagrams as intermediate states of an interaction process. They represent necessary intermediate states between observable real states. Such virtual particles were introduced to describe the interaction process between an electron and a positron and for much more complicated interaction processes. Other candidates for virtual particles are evanescent modes in optics and in elastic fields. Evanescent modes have a purely imaginary wave number, they represent the mathematical analogy of the tunneling solutions of the Schrödinger equation. Evanescent modes exist in the forbidden frequency bands of a photonic lattice and in undersized wave guides, for instance. The most prominent example for the occurrence of evanescent modes is the frustrated total internal reflection (FTIR at double prisms. Evanescent modes and tunneling lie outside the bounds of the special theory of relativity. They can cause faster than light (FTL signal velocities. We present examples of the quantum mechanical behavior of evanescent photons and phonons at a macroscopic scale. The evanescent modes of photons are described by virtual particles as predicted by former QED calculations.

  12. Quantum-limited heat conduction over macroscopic distances

    Science.gov (United States)

    Partanen, Matti; Tan, Kuan Yen; Govenius, Joonas; Lake, Russell E.; Mäkelä, Miika K.; Tanttu, Tuomo; Möttönen, Mikko

    2016-05-01

    The emerging quantum technological apparatuses, such as the quantum computer, call for extreme performance in thermal engineering. Cold distant heat sinks are needed for the quantized electric degrees of freedom owing to the increasing packaging density and heat dissipation. Importantly, quantum mechanics sets a fundamental upper limit for the flow of information and heat, which is quantified by the quantum of thermal conductance. However, the short distance between the heat-exchanging bodies in the previous experiments hinders their applicability in quantum technology. Here, we present experimental observations of quantum-limited heat conduction over macroscopic distances extending to a metre. We achieved this improvement of four orders of magnitude in the distance by utilizing microwave photons travelling in superconducting transmission lines. Thus, it seems that quantum-limited heat conduction has no fundamental distance cutoff. This work establishes the integration of normal-metal components into the framework of circuit quantum electrodynamics, which provides a basis for the superconducting quantum computer. Especially, our results facilitate remote cooling of nanoelectronic devices using faraway in situ-tunable heat sinks. Furthermore, quantum-limited heat conduction is important in contemporary thermodynamics. Here, the long distance may lead to ultimately efficient mesoscopic heat engines with promising practical applications.

  13. Thermodynamical properties and thermoelastic coupling of complex macroscopic structure

    International Nuclear Information System (INIS)

    Fabbri, M.; Sacripanti, A.

    1996-11-01

    Gross qualitative/quantitative analysis about thermodynamical properties and thermoelastic coupling (or elastocaloric effect) of complex macroscopic structure (running shoes) is performed by infrared camera. The experimental results showed the achievability of a n industrial research project

  14. Single-Phase Bundle Flows Including Macroscopic Turbulence Model

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Jun; Yoon, Han Young [KAERI, Daejeon (Korea, Republic of); Yoon, Seok Jong; Cho, Hyoung Kyu [Seoul National University, Seoul (Korea, Republic of)

    2016-05-15

    To deal with various thermal hydraulic phenomena due to rapid change of fluid properties when an accident happens, securing mechanistic approaches as much as possible may reduce the uncertainty arising from improper applications of the experimental models. In this study, the turbulence mixing model, which is well defined in the subchannel analysis code such as VIPRE, COBRA, and MATRA by experiments, is replaced by a macroscopic k-e turbulence model, which represents the aspect of mathematical derivation. The performance of CUPID with macroscopic turbulence model is validated against several bundle experiments: CNEN 4x4 and PNL 7x7 rod bundle tests. In this study, the macroscopic k-e model has been validated for the application to subchannel analysis. It has been implemented in the CUPID code and validated against CNEN 4x4 and PNL 7x7 rod bundle tests. The results showed that the macroscopic k-e turbulence model can estimate the experiments properly.

  15. Dynamical fusion thresholds in macroscopic and microscopic theories

    International Nuclear Information System (INIS)

    Davies, K.T.R.; Sierk, A.J.; Nix, J.R.

    1983-01-01

    Macroscopic and microscopic results demonstrating the existence of dynamical fusion thresholds are presented. For macroscopic theories, it is shown that the extra-push dynamics is sensitive to some details of the models used, e.g. the shape parametrization and the type of viscosity. The dependence of the effect upon the charge and angular momentum of the system is also studied. Calculated macroscopic results for mass-symmetric systems are compared to experimental mass-asymmetric results by use of a tentative scaling procedure, which takes into account both the entrance-channel and the saddle-point regions of configuration space. Two types of dynamical fusion thresholds occur in TDHF studies: (1) the microscopic analogue of the macroscopic extra push threshold, and (2) the relatively high energy at which the TDHF angular momentum window opens. Both of these microscopic thresholds are found to be very sensitive to the choice of the effective two-body interaction

  16. U(6)-phonon model of nuclear collective motion

    International Nuclear Information System (INIS)

    Ganev, H.G.

    2015-01-01

    The U(6)-phonon model of nuclear collective motion with the semi-direct product structure [HW(21)]U(6) is obtained as a hydrodynamic (macroscopic) limit of the fully microscopic proton–neutron symplectic model (PNSM) with Sp(12, R) dynamical group. The phonon structure of the [HW(21)]U(6) model enables it to simultaneously include the giant monopole and quadrupole, as well as dipole resonances and their coupling to the low-lying collective states. The U(6) intrinsic structure of the [HW(21)]U(6) model, from the other side, gives a framework for the simultaneous shell-model interpretation of the ground state band and the other excited low-lying collective bands. It follows then that the states of the whole nuclear Hilbert space which can be put into one-to-one correspondence with those of a 21-dimensional oscillator with an intrinsic (base) U(6) structure. The latter can be determined in such a way that it is compatible with the proton–neutron structure of the nucleus. The macroscopic limit of the Sp(12, R) algebra, therefore, provides a rigorous mechanism for implementing the unified model ideas of coupling the valence particles to the core collective degrees of freedom within a fully microscopic framework without introducing redundant variables or violating the Pauli principle. (author)

  17. Ballistic and diffusive dynamics in a two-dimensional ideal gas of macroscopic chaotic Faraday waves.

    Science.gov (United States)

    Welch, Kyle J; Hastings-Hauss, Isaac; Parthasarathy, Raghuveer; Corwin, Eric I

    2014-04-01

    We have constructed a macroscopic driven system of chaotic Faraday waves whose statistical mechanics, we find, are surprisingly simple, mimicking those of a thermal gas. We use real-time tracking of a single floating probe, energy equipartition, and the Stokes-Einstein relation to define and measure a pseudotemperature and diffusion constant and then self-consistently determine a coefficient of viscous friction for a test particle in this pseudothermal gas. Because of its simplicity, this system can serve as a model for direct experimental investigation of nonequilibrium statistical mechanics, much as the ideal gas epitomizes equilibrium statistical mechanics.

  18. Enabling real-time ultrasound imaging of soft tissue mechanical properties by simplification of the shear wave motion equation.

    Science.gov (United States)

    Engel, Aaron J; Bashford, Gregory R

    2015-08-01

    Ultrasound based shear wave elastography (SWE) is a technique used for non-invasive characterization and imaging of soft tissue mechanical properties. Robust estimation of shear wave propagation speed is essential for imaging of soft tissue mechanical properties. In this study we propose to estimate shear wave speed by inversion of the first-order wave equation following directional filtering. This approach relies on estimation of first-order derivatives which allows for accurate estimations using smaller smoothing filters than when estimating second-order derivatives. The performance was compared to three current methods used to estimate shear wave propagation speed: direct inversion of the wave equation (DIWE), time-to-peak (TTP) and cross-correlation (CC). The shear wave speed of three homogeneous phantoms of different elastic moduli (gelatin by weight of 5%, 7%, and 9%) were measured with each method. The proposed method was shown to produce shear speed estimates comparable to the conventional methods (standard deviation of measurements being 0.13 m/s, 0.05 m/s, and 0.12 m/s), but with simpler processing and usually less time (by a factor of 1, 13, and 20 for DIWE, CC, and TTP respectively). The proposed method was able to produce a 2-D speed estimate from a single direction of wave propagation in about four seconds using an off-the-shelf PC, showing the feasibility of performing real-time or near real-time elasticity imaging with dedicated hardware.

  19. On the equations of motion

    International Nuclear Information System (INIS)

    Jannussis, A.; Streclas, A.; Sourlas, D.; Vlachos, K.

    1977-01-01

    Using the theorem of the derivative of a function of operators with respect to any parameter, we can find the equation of motion of a system in classical mechanics, in canonical as well as in non-canonical mechanics

  20. On quantum effects in the dynamics of macroscopic test masses

    International Nuclear Information System (INIS)

    Mueller-Ebhardt, Helge

    2009-01-01

    This thesis provides theoretically a link between the increase of the sensitivity of gravitational-wave detectors and the possibility of preparing macroscopic quantum states in such detectors. In the first part of this thesis, we theoretically explore the quantum measurement noise of an optical speed meter topology, the Sagnac interferometer, equipped with an additional detuned cavity at the output port. This detuned signal-recycling technique was already investigated when applying it to a Michelson interferometer and is used in the gravitational-wave detector GEO600. Together with the quantum noise analysis of the simple Sagnac interferometer, it is the basis of our study: we optimize the Sagnac interferometer's sensitivity towards the detection of a certain gravitational-wave source in the vicinity of a realistic classical noise environment. Motivated by the fact that the Michelson interferometer, as a position meter, with detuned signal-recycling can transduce the gravitational-wave strain into real mirror motion, we compare the transducer effect in a speed and in a position meter. Furthermore, we theoretically investigate the conditional output squeezing of a cavity which is detuned with respect to its carrier and its subcarrier. Therewith we pursue the theoretical analysis of the ponderomotive squeezer. With the knowledge gained in the first part about the quantum measurement process in laser interferometers, the second part of this thesis comprises a theoretical analysis of the conditonal state in positon and momentum of the interferometer's test masses. We motivate not to obtain the conditional states from a stochastic master equation but with the help of the so-called Wiener filtering method. Using this method, we calculate the most general expression for the conditional covariance matrix of the Gaussian state of a test mass under any linear Markovian measurement process. Then we specify to the interferometry and theoretically show under which circumstances

  1. Structures of Staphylococcus aureus D-tagatose-6-phosphate kinase implicate domain motions in specificity and mechanism.

    Science.gov (United States)

    Miallau, Linda; Hunter, William N; McSweeney, Sean M; Leonard, Gordon A

    2007-07-06

    High resolution structures of Staphylococcus aureus d-tagatose-6-phosphate kinase (LacC) in two crystal forms are herein reported. The structures define LacC in apoform, in binary complexes with ADP or the co-factor analogue AMP-PNP, and in a ternary complex with AMP-PNP and D-tagatose-6-phosphate. The tertiary structure of the LacC monomer, which is closely related to other members of the pfkB subfamily of carbohydrate kinases, is composed of a large alpha/beta core domain and a smaller, largely beta "lid." Four extended polypeptide segments connect these two domains. Dimerization of LacC occurs via interactions between lid domains, which come together to form a beta-clasp structure. Residues from both subunits contribute to substrate binding. LacC adopts a closed structure required for phosphoryl transfer only when both substrate and co-factor are bound. A reaction mechanism similar to that used by other phosphoryl transferases is proposed, although unusually, when both substrate and co-factor are bound to the enzyme two Mg(2+) ions are observed in the active site. A new motif of amino acid sequence conservation common to the pfkB subfamily of carbohydrate kinases is identified.

  2. Provocative mechanical tests of the peripheral nervous system affect the joint torque-angle during passive knee motion.

    Science.gov (United States)

    Andrade, R J; Freitas, S R; Vaz, J R; Bruno, P M; Pezarat-Correia, P

    2015-06-01

    This study aimed to determine the influence of the head, upper trunk, and foot position on the passive knee extension (PKE) torque-angle response. PKE tests were performed in 10 healthy subjects using an isokinetic dynamometer at 2°/s. Subjects lay in the supine position with their hips flexed to 90°. The knee angle, passive torque, surface electromyography (EMG) of the semitendinosus and quadriceps vastus medialis, and stretch discomfort were recorded in six body positions during PKE. The different maximal active positions of the cervical spine (neutral; flexion; extension), thoracic spine (neutral; flexion), and ankle (neutral; dorsiflexion) were passively combined for the tests. Visual analog scale scores and EMG were unaffected by body segment positioning. An effect of the ankle joint was verified on the peak torque and knee maximum angle when the ankle was in the dorsiflexion position (P torque (P torque when the cervical and thoracic spines were flexed (P torque-angle response since different positions of head, upper trunk, and foot induce dissimilar knee mechanical responses during passive extension. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Real-time single-molecule tethered particle motion experiments reveal the kinetics and mechanisms of Cre-mediated site-specific recombination

    Science.gov (United States)

    Fan, Hsiu-Fang

    2012-01-01

    Tyrosine family recombinases (YRs) are widely utilized in genome engineering systems because they can easily direct DNA rearrangement. Cre recombinases, one of the most commonly used types of YRs, catalyze site-specific recombination between two loxP sites without the need for high-energy cofactors, other accessory proteins or a specific DNA target sequence between the loxP sites. Previous structural, analytical ultracentrifuge and electrophoretic analyses have provided details of the reaction kinetics and mechanisms of Cre recombinase activity; whether there are reaction intermediates or side pathways involved has been left unaddressed. Using tethered particle motion (TPM), the Cre-mediated site-specific recombination process has been delineated, from beginning to end, at the single-molecule level, including the formation of abortive complexes and wayward complexes blocking inactive nucleoprotein complexes from entering the recombination process. Reversibility in the strand-cleavage/-ligation process and the formation of a thermally stable Holliday junction intermediate were observed within the Cre-mediated site-specific recombination process. Rate constants for each elementary step, which explain the overall reaction outcomes under various conditions, were determined. Taking the findings of this study together, they demonstrate the potential of single-molecule methodology as an alternative approach for exploring reaction mechanisms in detail. PMID:22467208

  4. Quantum back-action-evading measurement of motion in a negative mass reference frame

    Science.gov (United States)

    Møller, Christoffer B.; Thomas, Rodrigo A.; Vasilakis, Georgios; Zeuthen, Emil; Tsaturyan, Yeghishe; Balabas, Mikhail; Jensen, Kasper; Schliesser, Albert; Hammerer, Klemens; Polzik, Eugene S.

    2017-07-01

    Quantum mechanics dictates that a continuous measurement of the position of an object imposes a random quantum back-action (QBA) perturbation on its momentum. This randomness translates with time into position uncertainty, thus leading to the well known uncertainty on the measurement of motion. As a consequence of this randomness, and in accordance with the Heisenberg uncertainty principle, the QBA puts a limitation—the so-called standard quantum limit—on the precision of sensing of position, velocity and acceleration. Here we show that QBA on a macroscopic mechanical oscillator can be evaded if the measurement of motion is conducted in the reference frame of an atomic spin oscillator. The collective quantum measurement on this hybrid system of two distant and disparate oscillators is performed with light. The mechanical oscillator is a vibrational ‘drum’ mode of a millimetre-sized dielectric membrane, and the spin oscillator is an atomic ensemble in a magnetic field. The spin oriented along the field corresponds to an energetically inverted spin population and realizes a negative-effective-mass oscillator, while the opposite orientation corresponds to an oscillator with positive effective mass. The QBA is suppressed by -1.8 decibels in the negative-mass setting and enhanced by 2.4 decibels in the positive-mass case. This hybrid quantum system paves the way to entanglement generation and distant quantum communication between mechanical and spin systems and to sensing of force, motion and gravity beyond the standard quantum limit.

  5. Quantum back-action-evading measurement of motion in a negative mass reference frame.

    Science.gov (United States)

    Møller, Christoffer B; Thomas, Rodrigo A; Vasilakis, Georgios; Zeuthen, Emil; Tsaturyan, Yeghishe; Balabas, Mikhail; Jensen, Kasper; Schliesser, Albert; Hammerer, Klemens; Polzik, Eugene S

    2017-07-12

    Quantum mechanics dictates that a continuous measurement of the position of an object imposes a random quantum back-action (QBA) perturbation on its momentum. This randomness translates with time into position uncertainty, thus leading to the well known uncertainty on the measurement of motion. As a consequence of this randomness, and in accordance with the Heisenberg uncertainty principle, the QBA puts a limitation-the so-called standard quantum limit-on the precision of sensing of position, velocity and acceleration. Here we show that QBA on a macroscopic mechanical oscillator can be evaded if the measurement of motion is conducted in the reference frame of an atomic spin oscillator. The collective quantum measurement on this hybrid system of two distant and disparate oscillators is performed with light. The mechanical oscillator is a vibrational 'drum' mode of a millimetre-sized dielectric membrane, and the spin oscillator is an atomic ensemble in a magnetic field. The spin oriented along the field corresponds to an energetically inverted spin population and realizes a negative-effective-mass oscillator, while the opposite orientation corresponds to an oscillator with positive effective mass. The QBA is suppressed by -1.8 decibels in the negative-mass setting and enhanced by 2.4 decibels in the positive-mass case. This hybrid quantum system paves the way to entanglement generation and distant quantum communication between mechanical and spin systems and to sensing of force, motion and gravity beyond the standard quantum limit.

  6. Mechanics

    CERN Document Server

    Chester, W

    1979-01-01

    When I began to write this book, I originally had in mind the needs of university students in their first year. May aim was to keep the mathematics simple. No advanced techniques are used and there are no complicated applications. The emphasis is on an understanding of the basic ideas and problems which require expertise but do not contribute to this understanding are not discussed. How­ ever, the presentation is more sophisticated than might be considered appropri­ ate for someone with no previous knowledge of the subject so that, although it is developed from the beginning, some previous acquaintance with the elements of the subject would be an advantage. In addition, some familiarity with element­ ary calculus is assumed but not with the elementary theory of differential equations, although knowledge of the latter would again be an advantage. It is my opinion that mechanics is best introduced through the motion of a particle, with rigid body problems left until the subject is more fully developed. Howev...

  7. 3D surface flow kinematics derived from airborne UAVSAR interferometric synthetic aperture radar to constrain the physical mechanisms controlling landslide motion

    Science.gov (United States)

    Delbridge, B. G.; Burgmann, R.; Fielding, E. J.; Hensley, S.; Schulz, W. H.

    2013-12-01

    This project focuses on improving our understanding of the physical mechanisms controlling landslide motion by studying the landslide-wide kinematics of the Slumgullion landslide in southwestern Colorado using interferometric synthetic aperture radar (InSAR) and GPS. The NASA/JPL UAVSAR airborne repeat-pass SAR interferometry system imaged the Slumgullion landslide from 4 look directions on eight flights in 2011 and 2012. Combining the four look directions allows us to extract the full 3-D velocity field of the surface. Observing the full 3-dimensional flow field allows us to extract the full strain tensor (assuming free surface boundary conditions and incompressible flow) since we have both the spatial resolution to take spatial derivates and full deformation information. COSMO-SkyMed(CSK) high-resolution Spotlight data was also acquired during time intervals overlapping with the UAVSAR one-week pairs, with intervals as short as one day. These observations allow for the quantitative testing of the deformation magnitude and estimated formal errors in the UAVSAR derived deformation field. We also test the agreement of the deformation at 20 GPS monitoring sites concurrently acquired by the USGS. We also utilize the temporal resolution of real-time GPS acquired by the UC Berkeley Active Tectonics Group during a temporary deployment from July 22nd - August 2nd. By combining this data with the kinematic data we hope to elucidate the response of the landslide to environmental changes such as rainfall, snowmelt, and atmospheric pressure, and consequently the mechanisms controlling the dynamics of the landslide system. To constrain the longer temporal dynamics, interferograms made from pairs of CSK images acquired in 2010, 2011, 2012 and 2013 reveal the slide deformation on a longer timescale by allowing us to measure meters of motion and see the average rates over year long intervals using pixel offset tracking of the high-resolution SAR amplitude images. The results of

  8. Microscopic to macroscopic depletion model development for FORMOSA-P

    International Nuclear Information System (INIS)

    Noh, J.M.; Turinsky, P.J.; Sarsour, H.N.

    1996-01-01

    Microscopic depletion has been gaining popularity with regard to employment in reactor core nodal calculations, mainly attributed to the superiority of microscopic depletion in treating spectral history effects during depletion. Another trend is the employment of loading pattern optimization computer codes in support of reload core design. Use of such optimization codes has significantly reduced design efforts to optimize reload core loading patterns associated with increasingly complicated lattice designs. A microscopic depletion model has been developed for the FORMOSA-P pressurized water reactor (PWR) loading pattern optimization code. This was done for both fidelity improvements and to make FORMOSA-P compatible with microscopic-based nuclear design methods. Needless to say, microscopic depletion requires more computational effort compared with macroscopic depletion. This implies that microscopic depletion may be computationally restrictive if employed during the loading pattern optimization calculation because many loading patterns are examined during the course of an optimization search. Therefore, the microscopic depletion model developed here uses combined models of microscopic and macroscopic depletion. This is done by first performing microscopic depletions for a subset of possible loading patterns from which 'collapsed' macroscopic cross sections are obtained. The collapsed macroscopic cross sections inherently incorporate spectral history effects. Subsequently, the optimization calculations are done using the collapsed macroscopic cross sections. Using this approach allows maintenance of microscopic depletion level accuracy without substantial additional computing resources

  9. Macroscopic quantum systems and gravitational phenomena

    International Nuclear Information System (INIS)

    Pikovski, I.

    2014-01-01

    Low-energy quantum systems are studied theoretically in light of possible experiments to test the interplay between quantum theory and general relativity. The research focus in this thesis is on quantum systems which can be controlled with very high precision and which allow for tests of quantum theory at novel scales in terms of mass and size. The pulsed regime of opto-mechanics is explored and it is shown how short optical pulses can be used to prepare and characterize quantum states of a massive mechanical resonator, and how some phenomenological models of quantum gravity can be probed. In addition, quantum interferometry with photons and matter-waves in the presence of gravitational time dilation is considered. It is shown that time dilation causes entanglement between internal states and the center-of-mass position and that it leads to decoherence of all composite quantum systems. The results of the thesis show that the interplay between quantum theory and general relativity affects even low-energy quantum systems and that it offers novel phenomena which can be probed in experiments. (author) [de

  10. NMR studies of macroscopic and microscopic properties of liquid crystals

    International Nuclear Information System (INIS)

    Hughes, J.R.

    1998-03-01

    The work presented is concerned with studies of orientational order in liquid crystals and the behaviour of certain mesophases. The experimental technique used in common with all the work is deuterium NMR spectroscopy. Much of the work involves studies of the orientational order of deuteriated solute molecules dissolved in liquid crystal solvents. Chapter 1 gives an introduction to liquid crystals followed by a quantitative description of orientational order. Deuterium NMR in liquid crystals is described and an outline of the molecular field theory behind the orientational order of a rigid, biaxial solute in a uniaxial mesophase is given. In Chapter 2 a novel type of mesophase induction is studied using NMR, where a solute induces up to two extra phases in a discotic mesogen depending on its concentration. The purpose of this work is to try to gain an understanding into the mechanism of the phase induction involved. Chapter 3 is concerned primarily with the macroscopic behaviour of the nematic phase formed by a semi-rigid main-chain polymer in solution. Of particular interest is the study of the reorientation of the monodomain, once the director has been rotated with respect to the magnetic field of the NMR spectrometer. A mesogen which has been claimed to exhibit a biaxial nematic phase is studied in Chapter 4, in order to determine the symmetry of the phase using NMR. Finally, Chapter 5 deals with the differing behaviour of a liquid crystal monomer and its dimer dissolved in common nematic solvents in order to determine whether this agrees with molecular field theory. (author)

  11. Bell-inequality tests with macroscopic entangled states of light

    Energy Technology Data Exchange (ETDEWEB)

    Stobinska, M. [Max Planck Institute for the Science of Light, Erlangen (Germany); Institute for Theoretical Physics II, Erlangen-Nuernberg University, Erlangen (Germany); Sekatski, P.; Gisin, N. [Group of Applied Physics, University of Geneva, Geneva (Switzerland); Buraczewski, A. [Faculty of Electronics and Information Technology, Warsaw University of Technology, Warsaw (Poland); Leuchs, G. [Max Planck Institute for the Science of Light, Erlangen (Germany); Institute for Optics, Information and Photonics, Erlangen-Nuernberg University, Erlangen (Germany)

    2011-09-15

    Quantum correlations may violate the Bell inequalities. Most experimental schemes confirming this prediction have been realized in all-optical Bell tests suffering from the detection loophole. Experiments which simultaneously close this loophole and the locality loophole are highly desirable and remain challenging. An approach to loophole-free Bell tests is based on amplification of the entangled photons (i.e., on macroscopic entanglement), for which an optical signal should be easy to detect. However, the macroscopic states are partially indistinguishable by classical detectors. An interesting idea to overcome these limitations is to replace the postselection by an appropriate preselection immediately after the amplification. This is in the spirit of state preprocessing revealing hidden nonlocality. Here, we examine one of the possible preselections, but the presented tools can be used for analysis of other schemes. Filtering methods making the macroscopic entanglement useful for Bell tests and quantum protocols are the subject of an intensive study in the field nowadays.

  12. Decoherence bypass of macroscopic superpositions in quantum measurement

    International Nuclear Information System (INIS)

    Spehner, Dominique; Haake, Fritz

    2008-01-01

    We study a class of quantum measurement models. A microscopic object is entangled with a macroscopic pointer such that a distinct pointer position is tied to each eigenvalue of the measured object observable. Those different pointer positions mutually decohere under the influence of an environment. Overcoming limitations of previous approaches we (i) cope with initial correlations between pointer and environment by considering them initially in a metastable local thermal equilibrium, (ii) allow for object-pointer entanglement and environment-induced decoherence of distinct pointer readouts to proceed simultaneously, such that mixtures of macroscopically distinct object-pointer product states arise without intervening macroscopic superpositions, and (iii) go beyond the Markovian treatment of decoherence. (fast track communication)

  13. The SH2 Domain Regulates c-Abl Kinase Activation by a Cyclin-Like Mechanism and Remodulation of the Hinge Motion

    Science.gov (United States)

    Dölker, Nicole; Górna, Maria W.; Sutto, Ludovico; Torralba, Antonio S.; Superti-Furga, Giulio; Gervasio, Francesco L.

    2014-01-01

    Regulation of the c-Abl (ABL1) tyrosine kinase is important because of its role in cellular signaling, and its relevance in the leukemiogenic counterpart (BCR-ABL). Both auto-inhibition and full activation of c-Abl are regulated by the interaction of the catalytic domain with the Src Homology 2 (SH2) domain. The mechanism by which this interaction enhances catalysis is not known. We combined computational simulations with mutagenesis and functional analysis to find that the SH2 domain conveys both local and global effects on the dynamics of the catalytic domain. Locally, it regulates the flexibility of the αC helix in a fashion reminiscent of cyclins in cyclin-dependent kinases, reorienting catalytically important motifs. At a more global level, SH2 binding redirects the hinge motion of the N and C lobes and changes the conformational equilibrium of the activation loop. The complex network of subtle structural shifts that link the SH2 domain with the activation loop and the active site may be partially conserved with other SH2-domain containing kinases and therefore offer additional parameters for the design of conformation-specific inhibitors. PMID:25299346

  14. The SH2 domain regulates c-Abl kinase activation by a cyclin-like mechanism and remodulation of the hinge motion.

    Science.gov (United States)

    Dölker, Nicole; Górna, Maria W; Sutto, Ludovico; Torralba, Antonio S; Superti-Furga, Giulio; Gervasio, Francesco L

    2014-10-01

    Regulation of the c-Abl (ABL1) tyrosine kinase is important because of its role in cellular signaling, and its relevance in the leukemiogenic counterpart (BCR-ABL). Both auto-inhibition and full activation of c-Abl are regulated by the interaction of the catalytic domain with the Src Homology 2 (SH2) domain. The mechanism by which this interaction enhances catalysis is not known. We combined computational simulations with mutagenesis and functional analysis to find that the SH2 domain conveys both local and global effects on the dynamics of the catalytic domain. Locally, it regulates the flexibility of the αC helix in a fashion reminiscent of cyclins in cyclin-dependent kinases, reorienting catalytically important motifs. At a more global level, SH2 binding redirects the hinge motion of the N and C lobes and changes the conformational equilibrium of the activation loop. The complex network of subtle structural shifts that link the SH2 domain with the activation loop and the active site may be partially conserved with other SH2-domain containing kinases and therefore offer additional parameters for the design of conformation-specific inhibitors.

  15. The SH2 domain regulates c-Abl kinase activation by a cyclin-like mechanism and remodulation of the hinge motion.

    Directory of Open Access Journals (Sweden)

    Nicole Dölker

    2014-10-01

    Full Text Available Regulation of the c-Abl (ABL1 tyrosine kinase is important because of its role in cellular signaling, and its relevance in the leukemiogenic counterpart (BCR-ABL. Both auto-inhibition and full activation of c-Abl are regulated by the interaction of the catalytic domain with the Src Homology 2 (SH2 domain. The mechanism by which this interaction enhances catalysis is not known. We combined computational simulations with mutagenesis and functional analysis to find that the SH2 domain conveys both local and global effects on the dynamics of the catalytic domain. Locally, it regulates the flexibility of the αC helix in a fashion reminiscent of cyclins in cyclin-dependent kinases, reorienting catalytically important motifs. At a more global level, SH2 binding redirects the hinge motion of the N and C lobes and changes the conformational equilibrium of the activation loop. The complex network of subtle structural shifts that link the SH2 domain with the activation loop and the active site may be partially conserved with other SH2-domain containing kinases and therefore offer additional parameters for the design of conformation-specific inhibitors.

  16. Light induced electrical and macroscopic changes in hydrogenated polymorphous silicon solar cells

    Directory of Open Access Journals (Sweden)

    Roca i Cabarrocas P.

    2012-07-01

    Full Text Available We report on light-induced electrical and macroscopic changes in hydrogenated polymorphous silicon (pm-Si:H PIN solar cells. To explain the particular light-soaking behavior of such cells – namely an increase of the open circuit voltage (Voc and a rapid drop of the short circuit current density (Jsc – we correlate these effects to changes in hydrogen incorporation and structural properties in the layers of the cells. Numerous techniques such as current-voltage characteristics, infrared spectroscopy, hydrogen exodiffusion, Raman spectroscopy, atomic force microscopy, scanning electron microscopy and spectroscopic ellipsometry are used to study the light-induced changes from microscopic to macroscopic scales (up to tens of microns. Such comprehensive use of complementary techniques lead us to suggest that light-soaking produces the diffusion of molecular hydrogen, hydrogen accumulation at p-layer/substrate interface and localized delamination of the interface. Based on these results we propose that light-induced degradation of PIN solar cells has to be addressed from not only as a material issue, but also a device point of view. In particular we bring experimental evidence that localized delamination at the interface between the p-layer and SnO2 substrate by light-induced hydrogen motion causes the rapid drop of Jsc.

  17. Plasmonic direct writing lithography with a macroscopical contact probe

    Science.gov (United States)

    Huang, Yuerong; Liu, Ling; Wang, Changtao; Chen, Weidong; Liu, Yunyue; Li, Ling

    2018-05-01

    In this work, we design a plasmonic direct writing lithography system with a macroscopical contact probe to achieve nanometer scale spots. The probe with bowtie-shaped aperture array adopts spring hinge and beam deflection method (BDM) to realize near-field lithography. Lithography results show that a macroscopical plasmonic contact probe can achieve a patterning resolution of around 75 nm at 365 nm wavelength, and demonstrate that the lithography system is promising for practical applications due to beyond the diffraction limit, low cost, and simplification of system configuration. CST calculations provide a guide for the design of recording structure and the arrangement of placing polarizer.

  18. Macroscopic and radiographic examination of proximal root surface caries

    International Nuclear Information System (INIS)

    Nordenram, G.; Bergvist, A.; Johnson, G.; Henriksen, C.O.; Anneroth, G.

    1988-01-01

    The purpose of the study was to compare macroscopic and radiographic examination of proximal root surface caries of extracted teeth from patients aged 65-95 years. Although the study conditions for macroscopic and radiographic diagnosis favored more sensitive evaluations than routine clinical conditions, there was a 24% disagreement in diagnosis. This finding indicates that under routine clinical conditions it is difficult to register with certainty all superficial root carious lesions. Even in the absence of clinically detectable root surface caries, preventive measures should be considered for elderly people with exposed root surfaces

  19. Triboelectricity: macroscopic charge patterns formed by self-arraying ions on polymer surfaces.

    Science.gov (United States)

    Burgo, Thiago A L; Ducati, Telma R D; Francisco, Kelly R; Clinckspoor, Karl J; Galembeck, Fernando; Galembeck, Sergio E

    2012-05-15

    Tribocharged polymers display macroscopically patterned positive and negative domains, verifying the fractal geometry of electrostatic mosaics previously detected by electric probe microscopy. Excess charge on contacting polyethylene (PE) and polytetrafluoroethylene (PTFE) follows the triboelectric series but with one caveat: net charge is the arithmetic sum of patterned positive and negative charges, as opposed to the usual assumption of uniform but opposite signal charging on each surface. Extraction with n-hexane preferentially removes positive charges from PTFE, while 1,1-difluoroethane and ethanol largely remove both positive and negative charges. Using suitable analytical techniques (electron energy-loss spectral imaging, infrared microspectrophotometry and carbonization/colorimetry) and theoretical calculations, the positive species were identified as hydrocarbocations and the negative species were identified as fluorocarbanions. A comprehensive model is presented for PTFE tribocharging with PE: mechanochemical chain homolytic rupture is followed by electron transfer from hydrocarbon free radicals to the more electronegative fluorocarbon radicals. Polymer ions self-assemble according to Flory-Huggins theory, thus forming the experimentally observed macroscopic patterns. These results show that tribocharging can only be understood by considering the complex chemical events triggered by mechanical action, coupled to well-established physicochemical concepts. Patterned polymers can be cut and mounted to make macroscopic electrets and multipoles.

  20. A constitutive model and numerical simulation of sintering processes at macroscopic level

    Science.gov (United States)

    Wawrzyk, Krzysztof; Kowalczyk, Piotr; Nosewicz, Szymon; Rojek, Jerzy

    2018-01-01

    This paper presents modelling of both single and double-phase powder sintering processes at the macroscopic level. In particular, its constitutive formulation, numerical implementation and numerical tests are described. The macroscopic constitutive model is based on the assumption that the sintered material is a continuous medium. The parameters of the constitutive model for material under sintering are determined by simulation of sintering at the microscopic level using a micro-scale model. Numerical tests were carried out for a cylindrical specimen under hydrostatic and uniaxial pressure. Results of macroscopic analysis are compared against the microscopic model results. Moreover, numerical simulations are validated by comparison with experimental results. The simulations and preparation of the model are carried out by Abaqus FEA - a software for finite element analysis and computer-aided engineering. A mechanical model is defined by the user procedure "Vumat" which is developed by the first author in Fortran programming language. Modelling presented in the paper can be used to optimize and to better understand the process.

  1. Sialic acid-triggered macroscopic properties switching on a smart polymer surface

    Science.gov (United States)

    Xiong, Yuting; Li, Minmin; Wang, Hongxi; Qing, Guangyan; Sun, Taolei

    2018-01-01

    Constructing smart surfaces with responsive polymers capable of dynamically and reversibly changing their chemical and physical properties by responding to the recognition of biomolecules remains a challenging task. And, the key to achieving this purpose relies on the design of polymers to precisely interact with the target molecule and successfully transform the interaction signal into tunable macroscopic properties, further achieve special bio-functions. Herein, inspired by carbohydrate-carbohydrate interaction (CCI) in life system, we developed a three-component copolymer poly(NIPAAm-co-PT-co-Glc) bearing a binding unit glucose (Glc) capable of recognizing sialic acid, a type of important molecular targets for cancer diagnosis and therapy, and reported the sialic acid triggered macroscopic properties switching on this smart polymer surface. Detailed mechanism studies indicated that multiple hydrogen bonding interactions between Glc unit and Neu5Ac destroyed the initial hydrogen bond network of the copolymer, leading to a reversible "contraction-to-swelling" conformational transition of the copolymer chains, accompanied with distinct macroscopic property switching (i.e., surface wettability, morphology, stiffness) of the copolymer film. And these features enabled this copolymer to selectively capture sialic acid-containing glycopeptides from complex protein samples. This work provides an inspiration for the design of novel smart polymeric materials with sensitive responsiveness to sialic acid, which would promote the development of sialic acid-specific bio-devices and drug delivery systems.

  2. Obstacles delaying the prompt deployment of piston-type mechanical cardiopulmonary resuscitation devices during emergency department resuscitation: a video-recording and time-motion study.

    Science.gov (United States)

    Huang, Edward Pei-Chuan; Wang, Hui-Chih; Ko, Patrick Chow-In; Chang, Anna Marie; Fu, Chia-Ming; Chen, Jiun-Wei; Liao, Yen-Chen; Liu, Hung-Chieh; Fang, Yao-De; Yang, Chih-Wei; Chiang, Wen-Chu; Ma, Matthew Huei-Ming; Chen, Shyr-Chyr

    2013-09-01

    The quality of cardiopulmonary resuscitation (CPR) is important to survival after cardiac arrest. Mechanical devices (MD) provide constant CPR, but their effectiveness may be affected by deployment timeliness. To identify the timeliness of the overall and of each essential step in the deployment of a piston-type MD during emergency department (ED) resuscitation, and to identify factors associated with delayed MD deployment by video recordings. Between December 2005 and December 2008, video clips from resuscitations with CPR sessions using a MD in the ED were reviewed using time-motion analyses. The overall deployment timeliness and the time spent on each essential step of deployment were measured. There were 37 CPR recordings that used a MD. Deployment of MD took an average 122.6 ± 57.8s. The 3 most time-consuming steps were: (1) setting the device (57.8 ± 38.3s), (2) positioning the patient (33.4 ± 38.0 s), and (3) positioning the device (14.7 ± 9.5s). Total no flow time was 89.1 ± 41.2s (72.7% of total time) and associated with the 3 most time-consuming steps. There was no difference in the total timeliness, no-flow time, and no-flow ratio between different rescuer numbers, time of day of the resuscitation, or body size of patients. Rescuers spent a significant amount of time on MD deployment, leading to long no-flow times. Lack of familiarity with the device and positioning strategy were associated with poor performance. Additional training in device deployment strategies are required to improve the benefits of mechanical CPR. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  3. Motion of magnetotactic microorganisms

    International Nuclear Information System (INIS)

    Esquivel, D.M.S.; Barros, H.G. de P.L. de.

    1985-01-01

    Magnetic moments for different magnetotactic microorganisms are obtained by electron microscopy analyses and studies of motion by optical microscopy. The results are analysed in terms of a model due to C.Bean. The considerations presented suggest that magnetotaxy is an efficient mechanism for orientation only if the time for reorientation is smaller than the cycles of environmental perturbations. (Author) [pt

  4. Macroscopic Spacetime Shortcuts in the Manyfold Universe

    CERN Document Server

    Loup, F

    2004-01-01

    Recently the idea of a Manyfold Universe was proposed by some authors to explain Dark Matter . In this study we assume that the Standard Model(SM) of particles and fields with gravity propagating in the Higher Dimensional Spacetime(Bulk) while other interactions are confined to 3+1 Einsteinian spacetime(Brane) is not due to open strings and closed loops but instead is due to the capability of gravity as the weakest and "smallest" interaction to penetrate these small Bulk size ($10^{-31}$m to $10^{-35}$m) while protons,neutrons and other interactions stronger and "larger" than gravity do not "fits" in the size of the Bulk and remains trapped on the Brane and we present a equation to justify this point of view. Our picture relies over the geometrical beauty of the Manyfold Universe proposal that Dark Matter is chemically identical to ordinary matter but lies on other Folds. Also the geometrical point of view for the small size of the Bulk eliminates the need of trapping mechanisms to confine matter in the Brane...

  5. Macroscopic properties of model disordered materials

    International Nuclear Information System (INIS)

    Knackstedt, M.A.; Roberts, A.P.

    1996-01-01

    Disordered materials are ubiquitous in nature and in industry. Soils, sedimentary rocks, wood, bone, polymer composites, foams, catalysts, gels, concretes and ceramics have properties that depend on material structure. Present techniques for predicting properties are limited by the theoretical and computational difficulty of incorporating a realistic description of material structure. A general model for microstructure was recently proposed by Berk [Berk, Phys.Rev.A, 44 5069 (1991)]. The model is based on level cuts of a Gaussian random field with arbitrary spectral density. The freedom in specifying the parameters of the model allows the modeling of physical materials with diverse morphological characteristics. We have shown that the model qualitatively accounts for the principal features of a wider variety of disordered materials including geologic media, membranes, polymer blends, ceramics and foams. Correlation functions are derived for the model microstructure. From this characterisation we derive mechanical and conductive properties of the materials. Excellent agreement with experimentally measured properties of disordered solids is obtained. The agreement provides a strong hint that it is now possible to correlate effective physical properties of porous solids to microstructure. Simple extensions to modelling properties of non-porous multicomponent blends; metal alloys, ceramics, metal/matrix and polymer composites are also discussed

  6. Penetration of fast projectiles into resistant media: From macroscopic to subatomic projectiles

    Science.gov (United States)

    Gaite, José

    2017-09-01

    The penetration of a fast projectile into a resistant medium is a complex process that is suitable for simple modeling, in which basic physical principles can be profitably employed. This study connects two different domains: the fast motion of macroscopic bodies in resistant media and the interaction of charged subatomic particles with matter at high energies, which furnish the two limit cases of the problem of penetrating projectiles of different sizes. These limit cases actually have overlapping applications; for example, in space physics and technology. The intermediate or mesoscopic domain finds application in atom cluster implantation technology. Here it is shown that the penetration of fast nano-projectiles is ruled by a slightly modified Newton's inertial quadratic force, namely, F ∼v 2 - β, where β vanishes as the inverse of projectile diameter. Factors essential to penetration depth are ratio of projectile to medium density and projectile shape.

  7. Description of nuclear collective motion by Wigner function moments

    International Nuclear Information System (INIS)

    Balbutsev, E.B.

    1996-01-01

    The method is presented in which the collective motion is described by the dynamic equations for the nuclear integral characteristics. The 'macroscopic' dynamics is formulated starting from the equations of the microscopic theory. This is done by taking the phase space moments of the Wigner function equation. The theory is applied to the description of collective excitations with multipolarities up to λ=5. (author)

  8. Mechanisms of dynamic deformation and dynamic failure in aluminum nitride

    International Nuclear Information System (INIS)

    Hu Guangli; Chen, C.Q.; Ramesh, K.T.; McCauley, J.W.

    2012-01-01

    Uniaxial quasi-static, uniaxial dynamic and confined dynamic compression experiments have been performed to characterize the failure and deformation mechanisms of a sintered polycrystalline aluminum nitride using a servohydraulic machine and a modified Kolsky bar. Scanning electron microscopy and transmission electron microscopy (TEM) are used to identify the fracture and deformation mechanisms under high rate and high pressure loading conditions. These results show that the fracture mechanisms are strong functions of confining stress and strain rate, with transgranular fracture becoming more common at high strain rates. Dynamic fracture mechanics and micromechanical models are used to analyze the observed fracture mechanisms. TEM characterization of fragments from the confined dynamic experiments shows that at higher pressures dislocation motion becomes a common dominant deformation mechanism in AlN. Prismatic slip is dominant, and pronounced microcrack–dislocation interactions are observed, suggesting that the dislocation plasticity affects the macroscopic fracture behavior in this material under high confining stresses.

  9. Quantum Measurement Backaction and Upconverting Microwave Signals with Mechanical Resonators

    Science.gov (United States)

    Peterson, R. W.

    The limits of optical measurement and control of mechanical motion are set by the quantum nature of light. The familiar shot noise limit can be avoided by increasing the optical power, but at high enough powers, the backaction of the randomly-arriving photons' radiation pressure can grow to become the dominant force on the system. This thesis will describe an experiment showing how backaction limits the laser cooling of macroscopic drumhead membranes, as well as work on how these membranes can be used to upconvert microwave signals to optical frequencies, potentially preserving the fragile quantum state of the upconverted signal.

  10. Random blebbing motion: A simple model linking cell structural properties to migration characteristics

    Science.gov (United States)

    Woolley, Thomas E.; Gaffney, Eamonn A.; Goriely, Alain

    2017-07-01

    If the plasma membrane of a cell is able to delaminate locally from its actin cortex, a cellular bleb can be produced. Blebs are pressure-driven protrusions, which are noteworthy for their ability to produce cellular motion. Starting from a general continuum mechanics description, we restrict ourselves to considering cell and bleb shapes that maintain approximately spherical forms. From this assumption, we obtain a tractable algebraic system for bleb formation. By including cell-substrate adhesions, we can model blebbing cell motility. Further, by considering mechanically isolated blebbing events, which are randomly distributed over the cell, we can derive equations linking the macroscopic migration characteristics to the microscopic structural parameters of the cell. This multiscale modeling framework is then used to provide parameter estimates, which are in agreement with current experimental data. In summary, the construction of the mathematical model provides testable relationships between the bleb size and cell motility.

  11. Random blebbing motion: A simple model linking cell structural properties to migration characteristics.

    Science.gov (United States)

    Woolley, Thomas E; Gaffney, Eamonn A; Goriely, Alain

    2017-07-01

    If the plasma membrane of a cell is able to delaminate locally from its actin cortex, a cellular bleb can be produced. Blebs are pressure-driven protrusions, which are noteworthy for their ability to produce cellular motion. Starting from a general continuum mechanics description, we restrict ourselves to considering cell and bleb shapes that maintain approximately spherical forms. From this assumption, we obtain a tractable algebraic system for bleb formation. By including cell-substrate adhesions, we can model blebbing cell motility. Further, by considering mechanically isolated blebbing events, which are randomly distributed over the cell, we can derive equations linking the macroscopic migration characteristics to the microscopic structural parameters of the cell. This multiscale modeling framework is then used to provide parameter estimates, which are in agreement with current experimental data. In summary, the construction of the mathematical model provides testable relationships between the bleb size and cell motility.

  12. Vascular flora and macroscopic fauna on the Fernow Experimental Forest

    Science.gov (United States)

    Darlene M. Madarish; Jane L. Rodrigue; Mary Beth Adams

    2002-01-01

    This report is the first comprehensive inventory of the vascular flora and macroscopic fauna known to occur within the Fernow Experimental Forest in north-central West Virignia. The compendium is based on information obtained from previous surveys, current research, and the personal observations of USDA Forest Service personnel and independent scientists. More than 750...

  13. On the problem of contextuality in macroscopic magnetization measurements

    International Nuclear Information System (INIS)

    Soeda, Akihito; Kurzyński, Paweł; Ramanathan, Ravishankar; Grudka, Andrzej; Thompson, Jayne; Kaszlikowski, Dagomir

    2013-01-01

    We show that sharp measurements of total magnetization cannot be used to reveal contextuality in macroscopic many-body systems of spins of arbitrary dimension. We decompose each such measurement into set of projectors corresponding to well-defined value of total magnetization. We then show that such sets of projectors are too restricted to construct Kochen–Specker sets.

  14. Photoinduced macroscopic chiral structures in a series of azobenzene copolyesters

    DEFF Research Database (Denmark)

    Nedelchev, L.; Nikolova, L.; Matharu, A.

    2002-01-01

    A study of the propagation of elliptically polarized light and the resulting formation of macroscopic chiral structures in a series of azobenzene side-chain copolyesters, in which the morphology is varied from liquid crystalline to amorphous, is reported. Real-time measurements are presented...

  15. Modification of the Charlesby law. Pt. 2. Macroscopic sensitivity

    International Nuclear Information System (INIS)

    Schiltz, A.; Weil, A.; Paniez, P.

    1984-01-01

    In part II, results are presented showing that for doses below macroscopic sensitivity, Qsub(sm), degradation due to fluence of the particles seems to be non-uniform over the entire area. In the light of this, a modification of the Charlesby's law is proposed providing a solution to the problems considered in part I [fr

  16. Charge of a macroscopic particle in a plasma sheath

    International Nuclear Information System (INIS)

    Samarian, A.A.; Vladimirov, S.V.

    2003-01-01

    Charging of a macroscopic body levitating in a rf plasma sheath is studied experimentally and theoretically. The nonlinear charge vs size dependence is obtained. The observed nonlinearity is explained on the basis of an approach taking into account different plasma conditions for the levitation positions of different particles. The importance of suprathermal electrons' contribution to the charging process is demonstrated

  17. Macroscopic Fundamental Diagram for pedestrian networks : Theory and applications

    NARCIS (Netherlands)

    Hoogendoorn, S.P.; Daamen, W.; Knoop, V.L.; Steenbakkers, Jeroen; Sarvi, Majid

    2017-01-01

    The Macroscopic Fundamental diagram (MFD) has proven to be a powerful concept in understanding and managing vehicular network dynamics, both from a theoretical angle and from a more application-oriented perspective. In this contribution, we explore the existence and the characteristics of the

  18. Emergence of an urban traffic macroscopic fundamental diagram

    DEFF Research Database (Denmark)

    Ranjan, Abhishek; Fosgerau, Mogens; Jenelius, Erik

    2016-01-01

    This paper examines mild conditions under which a macroscopic fundamental diagram (MFD) emerges, relating space-averaged speed to occupancy in some area. These conditions are validated against empirical data. We allow local speedoccupancy relationships and, in particular, require no equilibrating...

  19. Stereodynamics: From elementary processes to macroscopic chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Toshio [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Graduate School of Science, Department of Chemistry, Osaka University, Toyonaka, 560-0043 Osaka (Japan); Che, Dock-Chil [Graduate School of Science, Department of Chemistry, Osaka University, Toyonaka, 560-0043 Osaka (Japan); Tsai, Po-Yu [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Lin, King-Chuen [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Palazzetti, Federico [Scuola Normale Superiore, Pisa (Italy); Dipartimento di Chimica Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Aquilanti, Vincenzo [Dipartimento di Chimica Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Roma (Italy); Instituto de Fisica, Universidade Federal da Bahia, Salvador (Brazil)

    2015-12-31

    This paper aims at discussing new facets on stereodynamical behaviors in chemical reactions, i.e. the effects of molecular orientation and alignment on reactive processes. Further topics on macroscopic processes involving deviations from Arrhenius behavior in the temperature dependence of chemical reactions and chirality effects in collisions are also discussed.

  20. Microstructure and macroscopic properties of polydisperse systems of hard spheres

    NARCIS (Netherlands)

    Ogarko, V.

    2014-01-01

    This dissertation describes an investigation of systems of polydisperse smooth hard spheres. This includes the development of a fast contact detection algorithm for computer modelling, the development of macroscopic constitutive laws that are based on microscopic features such as the moments of the

  1. Macroscopic domain formation in the platelet plasma membrane

    DEFF Research Database (Denmark)

    Bali, Rachna; Savino, Laura; Ramirez, Diego A.

    2009-01-01

    There has been ample debate on whether cell membranes can present macroscopic lipid domains as predicted by three-component phase diagrams obtained by fluorescence microscopy. Several groups have argued that membrane proteins and interactions with the cytoskeleton inhibit the formation of large d...

  2. Macroscopic charge quantization in single-electron devices

    NARCIS (Netherlands)

    Burmistrov, I.S.; Pruisken, A.M.M.

    2010-01-01

    In a recent paper by the authors [I. S. Burmistrov and A. M. M. Pruisken, Phys. Rev. Lett. 101, 056801 (2008)] it was shown that single-electron devices (single-electron transistor or SET) display "macroscopic charge quantization" which is completely analogous to the quantum Hall effect observed on

  3. Macroscopic and microscopic magnetism of metal-metalloid amorphous alloys

    International Nuclear Information System (INIS)

    Vasconcellos, M.A.Z.; Fichtner, P.F.P.; Livi, F.P.; Costa, M.I. da; Baibich, M.N.

    1984-01-01

    In this paper is investigated the interrelation between macroscopic and microscopic magnetic phenomena using experimetnal data from Moessbauer effect and the magnetization of layers of amorphous (Fe 1-x Ni x ) 80 B 20 . The Moessbauer effect measurement show a distribution of hyperfine fields in Fe site as well as a likely distribution of isomeric shifts (M.W.O.) [pt

  4. A quantal transport theory for nuclear collective motion: the merits of a locally harmonic approximation

    International Nuclear Information System (INIS)

    Hofmann, H.

    1997-01-01

    A transport theory is developed for collective motion of systems such as an atomic nucleus, which may be considered as a typical representative of a self-bound micro-system. Albeit for pragmatic reasons, collective variables are introduced as shape parameters, self-consistency with respect to the nucleonic degrees of freedom has been implemented at various important stages. This feature leads to subsidiary conditions which are obeyed locally for both the average motion as well as for the quantized Hamiltonian constructed through a Bohm-Pines procedure. Furthermore, self-consistency governs the definition of the transport coefficients appearing in the equations for collective motion. The latter is associated to the time evolution of the density in collective phase space, for which the concept of the Wigner function is employed. Global motion is described by propagating the system in successive time laps which are macroscopically small, but microscopically large. This enables one to exploit linearization procedures and to take advantage of the benefits of linear response theory. A microscopic damping mechanism is introduced by dressing the energies of the independent particle model by complex self-energies, the parameters of which are determined from optical model considerations. Numerical evaluations of transport coefficients are described and tested for the case of fission in the light of recent experimental findings. The theory allows one to extend both Kramers' picture of this process as well as his equation for the density distribution into the quantum regime. (orig.)

  5. Can We Advance Macroscopic Quantum Systems Outside the Framework of Complex Decoherence Theory?

    Science.gov (United States)

    Brezinski, Mark E; Rupnick, Maria

    2016-01-01

    Macroscopic quantum systems (MQS) are macroscopic systems driven by quantum rather than classical mechanics, a long studied area with minimal success till recently. Harnessing the benefits of quantum mechanics on a macroscopic level would revolutionize fields ranging from telecommunication to biology, the latter focused on here for reasons discussed. Contrary to misconceptions, there are no known physical laws that prevent the development of MQS. Instead, they are generally believed universally lost in complex systems from environmental entanglements (decoherence). But we argue success is achievable MQS with decoherence compensation developed, naturally or artificially, from top-down rather current reductionist approaches. This paper advances the MQS field by a complex systems approach to decoherence. First, why complex system decoherence approaches (top-down) are needed is discussed. Specifically, complex adaptive systems (CAS) are not amenable to reductionist models (and their master equations) because of emergent behaviour, approximation failures, not accounting for quantum compensatory mechanisms, ignoring path integrals, and the subentity problem. In addition, since MQS must exist within the context of the classical world, where rapid decoherence and prolonged coherence are both needed. Nature has already demonstrated this for quantum subsystems such as photosynthesis and magnetoreception. Second, we perform a preliminary study that illustrates a top-down approach to potential MQS. In summary, reductionist arguments against MQS are not justifiable. It is more likely they are not easily detectable in large intact classical systems or have been destroyed by reductionist experimental set-ups. This complex systems decoherence approach, using top down investigations, is critical to paradigm shifts in MQS research both in biological and non-biological systems. PMID:29200743

  6. Melt layer macroscopic erosion of tungsten and other metals under plasma heat loads simulating ITER off-normal events

    International Nuclear Information System (INIS)

    Garkusha, I.E.; Bandura, A.N.; Byrka, O.V.; Kulik, N.V.; Landman, I.; Wuerz, H.

    2002-01-01

    This paper is focused on experimental analysis of metal layer erosion and droplet splashing of tungsten and other metals under heat loads typical for ITER FEAT off-normal events,such as disruptions and VDE's. Plasma pressure gradient action on melt layer results in erosion crater formation with mountains of displaced material at the crater edge. It is shown that macroscopic motion of melt layer and surface cracking are the main factors responsible for tungsten damage. Weight loss measurements of all exposed materials demonstrate inessential contribution of evaporation process to metals erosion

  7. Topical review: spins and mechanics in diamond

    Science.gov (United States)

    Lee, Donghun; Lee, Kenneth W.; Cady, Jeffrey V.; Ovartchaiyapong, Preeti; Bleszynski Jayich, Ania C.

    2017-03-01

    There has been rapidly growing interest in hybrid quantum devices involving a solid-state spin and a macroscopic mechanical oscillator. Such hybrid devices create exciting opportunities to mediate interactions between disparate quantum bits (qubits) and to explore the quantum regime of macroscopic mechanical objects. In particular, a system consisting of the nitrogen-vacancy defect center (NV center) in diamond coupled to a high-quality-factor mechanical oscillator is an appealing candidate for such a hybrid quantum device, as it utilizes the highly coherent and versatile spin properties of the defect center. In this paper, we will review recent experimental progress on diamond-based hybrid quantum devices in which the spin and orbital dynamics of single defects are driven by the motion of a mechanical oscillator. In addition, we discuss prospective applications for this device, including long-range, phonon-mediated spin-spin interactions, and phonon cooling in the quantum regime. We conclude the review by evaluating the experimental limitations of current devices and identifying alternative device architectures that may reach the strong coupling regime.

  8. Experimental study of macroscopic quantum tunnelling in Bi2212 intrinsic Josephson junctions

    International Nuclear Information System (INIS)

    Matsumoto, Tetsuro; Kashiwaya, Hiromi; Shibata, Hajime; Kashiwaya, Satoshi; Kawabata, Shiro; Eisaki, Hiroshi; Yoshida, Yoshiyuki; Tanaka, Yukio

    2007-01-01

    The quantum dynamics of Bi 2 Sr 2 CaCu 2 O 8+δ intrinsic Josephson junctions (IJJs) is studied based on escape rate measurements. The saturations observed in the escape temperature and in the width of the switching current below 0.5 K (= T * ) indicate the transition of the switching mechanism from thermal activation to macroscopic quantum tunnelling. It is shown that the switching properties are consistently explained in terms of the underdamped Josephson junction with a quality factor of 70 ± 20 in spite of possible damping due to the nodal quasiparticles of d-wave superconductivity. The present result gives the upper limit of the damping of IJJs

  9. Polymorphic phase transitions: Macroscopic theory and molecular simulation.

    Science.gov (United States)

    Anwar, Jamshed; Zahn, Dirk

    2017-08-01

    Transformations in the solid state are of considerable interest, both for fundamental reasons and because they underpin important technological applications. The interest spans a wide spectrum of disciplines and application domains. For pharmaceuticals, a common issue is unexpected polymorphic transformation of the drug or excipient during processing or on storage, which can result in product failure. A more ambitious goal is that of exploiting the advantages of metastable polymorphs (e.g. higher solubility and dissolution rate) while ensuring their stability with respect to solid state transformation. To address these issues and to advance technology, there is an urgent need for significant insights that can only come from a detailed molecular level understanding of the involved processes. Whilst experimental approaches at best yield time- and space-averaged structural information, molecular simulation offers unprecedented, time-resolved molecular-level resolution of the processes taking place. This review aims to provide a comprehensive and critical account of state-of-the-art methods for modelling polymorph stability and transitions between solid phases. This is flanked by revisiting the associated macroscopic theoretical framework for phase transitions, including their classification, proposed molecular mechanisms, and kinetics. The simulation methods are presented in tutorial form, focusing on their application to phase transition phenomena. We describe molecular simulation studies for crystal structure prediction and polymorph screening, phase coexistence and phase diagrams, simulations of crystal-crystal transitions of various types (displacive/martensitic, reconstructive and diffusive), effects of defects, and phase stability and transitions at the nanoscale. Our selection of literature is intended to illustrate significant insights, concepts and understanding, as well as the current scope of using molecular simulations for understanding polymorphic

  10. Short-term changes in neck pain, widespread pressure pain sensitivity, and cervical range of motion after the application of trigger point dry needling in patients with acute mechanical neck pain: a randomized clinical trial.

    Science.gov (United States)

    Mejuto-Vázquez, María J; Salom-Moreno, Jaime; Ortega-Santiago, Ricardo; Truyols-Domínguez, Sebastián; Fernández-de-Las-Peñas, César

    2014-04-01

    Randomized clinical trial. To determine the effects of trigger point dry needling (TrPDN) on neck pain, widespread pressure pain sensitivity, and cervical range of motion in patients with acute mechanical neck pain and active trigger points in the upper trapezius muscle. TrPDN seems to be effective for decreasing pain in individuals with upper-quadrant pain syndromes. Potential effects of TrPDN for decreasing pain and sensitization in individuals with acute mechanical neck pain are needed. Methods Seventeen patients (53% female) were randomly assigned to 1 of 2 groups: a single session of TrPDN or no intervention (waiting list). Pressure pain thresholds over the C5-6 zygapophyseal joint, second metacarpal, and tibialis anterior muscle; neck pain intensity; and cervical spine range-of-motion data were collected at baseline (pretreatment) and 10 minutes and 1 week after the intervention by an assessor blinded to the treatment allocation of the patient. Mixed-model analyses of variance were used to examine the effects of treatment on each outcome variable. Patients treated with 1 session of TrPDN experienced greater decreases in neck pain, greater increases in pressure pain threshold, and higher increases in cervical range of motion than those who did not receive an intervention at both 10 minutes and 1 week after the intervention (Ppain intensity and widespread pressure pain sensitivity, and also increase active cervical range of motion, in patients with acute mechanical neck pain. Changes in pain, pressure pain threshold, and cervical range of motion surpassed their respective minimal detectable change values, supporting clinically relevant treatment effects. Level of Evidence Therapy, level 1b-.

  11. Evolution of Quantum Systems from Microscopic to Macroscopic Scales

    International Nuclear Information System (INIS)

    Ovchinnikov, Sergey Y.; Macek, Joseph H.; Sternberg, James S.; Lee, Teck-Ghee; Schultz, David R.

    2009-01-01

    Even though the static properties of quantum systems have been known since the early days of quantum mechanics, accurate simulation of the dynamical break-up or ionization remains a theoretical challenge despite our complete knowledge of the relevant interactions. Simulations are challenging because of highly oscillatory exponential phase factors in the electronic wave function and the infinitesimally small values of the continuum components of electronic probability density at large times after the collision. The approach we recently developed, the regularized time-dependent Schroedinger equation method, has addressed these difficulties by removing the diverging phase factors and transforming the time-dependent Schroedinger equation to an expanding space. The evolution of the electronic wave function was followed to internuclear distances of R = 100,000 a.u. or 5 microns, which is of the order of the diameter of a human hair. Our calculations also revealed unexpected presence of free vortices in the electronic wave function. The discovered vortices also bring new light on the mechanism of transferring of the angular momentum from an external to internal motion. The connection between the observable momentum distribution and the time-dependent wave function implies that vortices in the wave function at large times are imaged in the momentum distribution.

  12. Inverse Bayesian inference as a key of consciousness featuring a macroscopic quantum logical structure.

    Science.gov (United States)

    Gunji, Yukio-Pegio; Shinohara, Shuji; Haruna, Taichi; Basios, Vasileios

    2017-02-01

    To overcome the dualism between mind and matter and to implement consciousness in science, a physical entity has to be embedded with a measurement process. Although quantum mechanics have been regarded as a candidate for implementing consciousness, nature at its macroscopic level is inconsistent with quantum mechanics. We propose a measurement-oriented inference system comprising Bayesian and inverse Bayesian inferences. While Bayesian inference contracts probability space, the newly defined inverse one relaxes the space. These two inferences allow an agent to make a decision corresponding to an immediate change in their environment. They generate a particular pattern of joint probability for data and hypotheses, comprising multiple diagonal and noisy matrices. This is expressed as a nondistributive orthomodular lattice equivalent to quantum logic. We also show that an orthomodular lattice can reveal information generated by inverse syllogism as well as the solutions to the frame and symbol-grounding problems. Our model is the first to connect macroscopic cognitive processes with the mathematical structure of quantum mechanics with no additional assumptions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Elucidation of molecular kinetic schemes from macroscopic traces using system identification.

    Directory of Open Access Journals (Sweden)

    Miguel Fribourg

    2017-02-01

    Full Text Available Overall cellular responses to biologically-relevant stimuli are mediated by networks of simpler lower-level processes. Although information about some of these processes can now be obtained by visualizing and recording events at the molecular level, this is still possible only in especially favorable cases. Therefore the development of methods to extract the dynamics and relationships between the different lower-level (microscopic processes from the overall (macroscopic response remains a crucial challenge in the understanding of many aspects of physiology. Here we have devised a hybrid computational-analytical method to accomplish this task, the SYStems-based MOLecular kinetic scheme Extractor (SYSMOLE. SYSMOLE utilizes system-identification input-output analysis to obtain a transfer function between the stimulus and the overall cellular response in the Laplace-transformed domain. It then derives a Markov-chain state molecular kinetic scheme uniquely associated with the transfer function by means of a classification procedure and an analytical step that imposes general biological constraints. We first tested SYSMOLE with synthetic data and evaluated its performance in terms of its rate of convergence to the correct molecular kinetic scheme and its robustness to noise. We then examined its performance on real experimental traces by analyzing macroscopic calcium-current traces elicited by membrane depolarization. SYSMOLE derived the correct, previously known molecular kinetic scheme describing the activation and inactivation of the underlying calcium channels and correctly identified the accepted mechanism of action of nifedipine, a calcium-channel blocker clinically used in patients with cardiovascular disease. Finally, we applied SYSMOLE to study the pharmacology of a new class of glutamate antipsychotic drugs and their crosstalk mechanism through a heteromeric complex of G protein-coupled receptors. Our results indicate that our methodology

  14. Using Non-linear Homogenization to Improve the Performance of Macroscopic Damage Models of Trabecular Bone.

    Science.gov (United States)

    Levrero-Florencio, Francesc; Pankaj, Pankaj

    2018-01-01

    Realistic macro-level finite element simulations of the mechanical behavior of trabecular bone, a cellular anisotropic material, require a suitable constitutive model; a model that incorporates the mechanical response of bone for complex loading scenarios and includes post-elastic phenomena, such as plasticity (permanent deformations) and damage (permanent stiffness reduction), which bone is likely to experience. Some such models have been developed by conducting homogenization-based multiscale finite element simulations on bone micro-structure. While homogenization has been fairly successful in the elastic regime and, to some extent, in modeling the macroscopic plastic response, it has remained a challenge with respect to modeling damage. This study uses a homogenization scheme to upscale the damage behavior from the tissue level (microscale) to the organ level (macroscale) and assesses the suitability of different damage constitutive laws. Ten cubic specimens were each subjected to 21 strain-controlled load cases for a small range of macroscopic post-elastic strains. Isotropic and anisotropic criteria were considered, density and fabric relationships were used in the formulation of the damage law, and a combined isotropic/anisotropic law with tension/compression asymmetry was formulated, based on the homogenized results, as a possible alternative to the currently used single scalar damage criterion. This computational study enhances the current knowledge on the macroscopic damage behavior of trabecular bone. By developing relationships of damage progression with bone's micro-architectural indices (density and fabric) the study also provides an aid for the creation of more precise macroscale continuum models, which are likely to improve clinical predictions.

  15. Wave speeds in the macroscopic extended model for ultrarelativistic gases

    Energy Technology Data Exchange (ETDEWEB)

    Borghero, F., E-mail: borghero@unica.it [Dip. Matematica e Informatica, Università di Cagliari, Via Ospedale 72, 09124 Cagliari (Italy); Demontis, F., E-mail: fdemontis@unica.it [Dip. Matematica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); Pennisi, S., E-mail: spennisi@unica.it [Dip. Matematica, Università di Cagliari, Via Ospedale 72, 09124 Cagliari (Italy)

    2013-11-15

    Equations determining wave speeds for a model of ultrarelativistic gases are investigated. This model is already present in literature; it deals with an arbitrary number of moments and it was proposed in the context of exact macroscopic approaches in Extended Thermodynamics. We find these results: the whole system for the determination of the wave speeds can be divided into independent subsystems which are expressed by linear combinations, through scalar coefficients, of tensors all of the same order; some wave speeds, but not all of them, are expressed by square roots of rational numbers; finally, we prove that these wave speeds for the macroscopic model are the same of those furnished by the kinetic model.

  16. Analysis and Enhancements of a Prolific Macroscopic Model of Epilepsy

    Directory of Open Access Journals (Sweden)

    Christopher Fietkiewicz

    2016-01-01

    Full Text Available Macroscopic models of epilepsy can deliver surprisingly realistic EEG simulations. In the present study, a prolific series of models is evaluated with regard to theoretical and computational concerns, and enhancements are developed. Specifically, we analyze three aspects of the models: (1 Using dynamical systems analysis, we demonstrate and explain the presence of direct current potentials in the simulated EEG that were previously undocumented. (2 We explain how the system was not ideally formulated for numerical integration of stochastic differential equations. A reformulated system is developed to support proper methodology. (3 We explain an unreported contradiction in the published model specification regarding the use of a mathematical reduction method. We then use the method to reduce the number of equations and further improve the computational efficiency. The intent of our critique is to enhance the evolution of macroscopic modeling of epilepsy and assist others who wish to explore this exciting class of models further.

  17. Macroscopic balance equations for two-phase flow models

    International Nuclear Information System (INIS)

    Hughes, E.D.

    1979-01-01

    The macroscopic, or overall, balance equations of mass, momentum, and energy are derived for a two-fluid model of two-phase flows in complex geometries. These equations provide a base for investigating methods of incorporating improved analysis methods into computer programs, such as RETRAN, which are used for transient and steady-state thermal-hydraulic analyses of nuclear steam supply systems. The equations are derived in a very general manner so that three-dimensional, compressible flows can be analysed. The equations obtained supplement the various partial differential equation two-fluid models of two-phase flow which have recently appeared in the literature. The primary objective of the investigation is the macroscopic balance equations. (Auth.)

  18. Macroscopic phase separation in high-temperature superconductors

    Science.gov (United States)

    Wen, Hai-Hu

    2000-01-01

    High-temperature superconductivity is recovered by introducing extra holes to the Cu-O planes, which initially are insulating with antiferromagnetism. In this paper I present data to show the macroscopic electronic phase separation that is caused by either mobile doping or electronic instability in the overdoped region. My results clearly demonstrate that the electronic inhomogeneity is probably a general feature of high-temperature superconductors. PMID:11027323

  19. Negative heat capacity at phase-separation in macroscopic systems

    OpenAIRE

    Gross, D. H. E.

    2005-01-01

    Systems with long-range as well with short-range interactions should necessarily have a convex entropy S(E) at proper phase transitions of first order, i.e. when a separation of phases occurs. Here the microcanonical heat capacity c(E)= -\\frac{(\\partial S/\\partial E)^2}{\\partial^2S/\\partial E^2} is negative. This should be observable even in macroscopic systems when energy fluctuations with the surrounding world can be sufficiently suppressed.

  20. Extension of Seismic Scanning Tunneling Macroscope to Elastic Waves

    KAUST Repository

    Tarhini, Ahmad

    2017-11-06

    The theory for the seismic scanning tunneling macroscope is extended from acoustic body waves to elastic body-wave propagation. We show that, similar to the acoustic case, near-field superresolution imaging from elastic body waves results from the O(1/R) term, where R is the distance between the source and near-field scatterer. The higher-order contributions R−n for n>1 are cancelled in the near-field region for a point source with normal stress.

  1. A macroscopic model for magnetic shape-memory single crystals

    Czech Academy of Sciences Publication Activity Database

    Bessoud, A. L.; Kružík, Martin; Stefanelli, U.

    2013-01-01

    Roč. 64, č. 2 (2013), s. 343-359 ISSN 0044-2275 R&D Projects: GA AV ČR IAA100750802; GA ČR GAP201/10/0357 Institutional support: RVO:67985556 Keywords : magnetostriction * evolution Subject RIV: BA - General Mathematics Impact factor: 1.214, year: 2013 http://library.utia.cas.cz/separaty/2012/MTR/kruzik-a macroscopic model for magnetic shape- memory single crystals.pdf

  2. Extension of Seismic Scanning Tunneling Macroscope to Elastic Waves

    KAUST Repository

    Tarhini, Ahmad; Guo, Bowen; Dutta, Gaurav; Schuster, Gerard T.

    2017-01-01

    The theory for the seismic scanning tunneling macroscope is extended from acoustic body waves to elastic body-wave propagation. We show that, similar to the acoustic case, near-field superresolution imaging from elastic body waves results from the O(1/R) term, where R is the distance between the source and near-field scatterer. The higher-order contributions R−n for n>1 are cancelled in the near-field region for a point source with normal stress.

  3. Toward a superconducting quantum computer. Harnessing macroscopic quantum coherence.

    Science.gov (United States)

    Tsai, Jaw-Shen

    2010-01-01

    Intensive research on the construction of superconducting quantum computers has produced numerous important achievements. The quantum bit (qubit), based on the Josephson junction, is at the heart of this research. This macroscopic system has the ability to control quantum coherence. This article reviews the current state of quantum computing as well as its history, and discusses its future. Although progress has been rapid, the field remains beset with unsolved issues, and there are still many new research opportunities open to physicists and engineers.

  4. Pseudo-Goldstone bosons and new macroscopic forces

    International Nuclear Information System (INIS)

    Hill, C.T.; Ross, G.G.

    1988-01-01

    Pseudoscalar Goldstone bosons may readily be associated with weakly, explicitly broken symmetries giving them mixed CP quantum numbers. In general this leads to scalar couplings to nucleons and leptons, which produces coherent long range forces. This can naturally accommodate detectable long range macroscopic forces mediated by bosons completely consistent with conventional cosmological limits, e.g., new interactions with the range of present 'fifth force' searches which probe a scale of new physics of f ≅ 10 14 GeV. (orig.)

  5. Macroscopic quantum electrodynamics of high-Q cavities

    International Nuclear Information System (INIS)

    Khanbekyan, Mikayel

    2009-01-01

    In this thesis macroscopic quantum electrodynamics in linear media was applied in order to develop an universally valid quantum theory for the description of the interaction of the electromagnetic field with atomic sources in high-Q cavities. In this theory a complete description of the characteristics of the emitted radiation is given. The theory allows to show the limits of the applicability of the usually applied theory. In order to establish an as possible generally valid theory first the atom-field interaction was studied in the framework of macroscopic quantum electrodynamics in dispersive and absorptive media. In order to describe the electromagnetic field from Maxwell's equations was started, whereby the noise-current densities, which are connected with the absorption of the medium, were included. The solution of these equations expresses the electromagnetic field variables by the noise-current densities by means of Green's tensor of the macroscopic Maxwell equations. The explicit quantization is performed by means of the noise-current densities, whereby a diagonal Hamiltonian is introduced, which then guarantees the time development according to Maxwell's equation and the fulfillment of the fundamental simultaneous commutation relations of the field variables. In the case of the interaction of the medium-supported field with atoms the Hamiltonian must be extended by atom-field interactions energies, whereby the canonical coupling schemes of the minimal or multipolar coupling can be used. The dieelectric properties of the material bodies as well as their shape are coded in the Green tensor of the macroscopic Maxwell equations. As preparing step first the Green tensor was specified in order to derive three-dimensional input-output relations for the electromagnetic field operators on a plane multilayer structure. Such a general dewscription of the electromagnetic field allows the inclusion both of dispersion and absorption of the media and the possible

  6. Neoclassical theory of electromagnetic interactions a single theory for macroscopic and microscopic scales

    CERN Document Server

    Babin, Anatoli

    2016-01-01

    In this monograph, the authors present their recently developed theory of electromagnetic interactions. This neoclassical approach extends the classical electromagnetic theory down to atomic scales and allows the explanation of various non-classical phenomena in the same framework. While the classical Maxwell–Lorentz electromagnetism theory succeeds in describing the physical reality at macroscopic scales, it struggles at atomic scales. Here, quantum mechanics traditionally takes over to describe non-classical phenomena such as the hydrogen spectrum and de Broglie waves. By means of modifying the classical theory, the approach presented here is able to consistently explain quantum-mechanical effects, and while similar to quantum mechanics in some respects, this neoclassical theory also differs markedly from it. In particular, the newly developed framework omits probabilistic interpretations of the wave function and features a new fundamental spatial scale which, at the size of the free electron, is much lar...

  7. Study on Tensile Properties of Nanoreinforced Epoxy Polymer: Macroscopic Experiments and Nanoscale FEM Simulation Prediction

    Directory of Open Access Journals (Sweden)

    Zhenqing Wang

    2013-01-01

    Full Text Available The effect of nanosilica contents on mechanical properties of the epoxy matrix with some nanoparticle aggregations was studied in macroscopic experiments and nanoscale simulation, particularly with regard to the effective modulus and ultimate stress. Three analytical models were used to obtain the effective elastic modulus of nanoparticle-reinforced composites. Based on Monte-Carlo method, the special program for the automatic generation of 2D random distribution particles without overlapping was developed for nanocomposite modeling. Weight fractions of nanoparticles were converted to volume fractions, in order to coordinate the content unit in the simulation. In numerical analysis, the weak interface strengthening and toughening mechanism was adopted. Virtual crack closure technique (VCCT and extended finite element method (XFEM were used to simulate phenomena of nanoparticle debonding and matrix crack growth. Experimental and simulation results show a good agreement with each other. By way of simulation, the weak interface toughening and strengthening mechanism of nanocomposites is confirmed.

  8. The mirrors model: macroscopic diffusion without noise or chaos

    International Nuclear Information System (INIS)

    Chiffaudel, Yann; Lefevere, Raphaël

    2016-01-01

    Before stating our main result, we first clarify through classical examples the status of the laws of macroscopic physics as laws of large numbers. We next consider the mirrors model in a finite d-dimensional domain and connected to particles reservoirs at fixed chemical potentials. The dynamics is purely deterministic and non-ergodic but takes place in a random environment. We study the macroscopic current of particles in the stationary regime. We show first that when the size of the system goes to infinity, the behaviour of the stationary current of particles is governed by the proportion of orbits crossing the system. This allows us to formulate a necessary and sufficient condition on the distribution of the set of orbits that ensures the validity of Fick’s law. Using this approach, we show that Fick’s law relating the stationary macroscopic current of particles to the concentration difference holds in three dimensions and above. The negative correlations between crossing orbits play a key role in the argument. (letter)

  9. Macroscopic phase-resetting curves for spiking neural networks

    Science.gov (United States)

    Dumont, Grégory; Ermentrout, G. Bard; Gutkin, Boris

    2017-10-01

    The study of brain rhythms is an open-ended, and challenging, subject of interest in neuroscience. One of the best tools for the understanding of oscillations at the single neuron level is the phase-resetting curve (PRC). Synchronization in networks of neurons, effects of noise on the rhythms, effects of transient stimuli on the ongoing rhythmic activity, and many other features can be understood by the PRC. However, most macroscopic brain rhythms are generated by large populations of neurons, and so far it has been unclear how the PRC formulation can be extended to these more common rhythms. In this paper, we describe a framework to determine a macroscopic PRC (mPRC) for a network of spiking excitatory and inhibitory neurons that generate a macroscopic rhythm. We take advantage of a thermodynamic approach combined with a reduction method to simplify the network description to a small number of ordinary differential equations. From this simplified but exact reduction, we can compute the mPRC via the standard adjoint method. Our theoretical findings are illustrated with and supported by numerical simulations of the full spiking network. Notably our mPRC framework allows us to predict the difference between effects of transient inputs to the excitatory versus the inhibitory neurons in the network.

  10. Macroscopic phase-resetting curves for spiking neural networks.

    Science.gov (United States)

    Dumont, Grégory; Ermentrout, G Bard; Gutkin, Boris

    2017-10-01

    The study of brain rhythms is an open-ended, and challenging, subject of interest in neuroscience. One of the best tools for the understanding of oscillations at the single neuron level is the phase-resetting curve (PRC). Synchronization in networks of neurons, effects of noise on the rhythms, effects of transient stimuli on the ongoing rhythmic activity, and many other features can be understood by the PRC. However, most macroscopic brain rhythms are generated by large populations of neurons, and so far it has been unclear how the PRC formulation can be extended to these more common rhythms. In this paper, we describe a framework to determine a macroscopic PRC (mPRC) for a network of spiking excitatory and inhibitory neurons that generate a macroscopic rhythm. We take advantage of a thermodynamic approach combined with a reduction method to simplify the network description to a small number of ordinary differential equations. From this simplified but exact reduction, we can compute the mPRC via the standard adjoint method. Our theoretical findings are illustrated with and supported by numerical simulations of the full spiking network. Notably our mPRC framework allows us to predict the difference between effects of transient inputs to the excitatory versus the inhibitory neurons in the network.

  11. Stochastic and Macroscopic Thermodynamics of Strongly Coupled Systems

    Directory of Open Access Journals (Sweden)

    Christopher Jarzynski

    2017-01-01

    Full Text Available We develop a thermodynamic framework that describes a classical system of interest S that is strongly coupled to its thermal environment E. Within this framework, seven key thermodynamic quantities—internal energy, entropy, volume, enthalpy, Gibbs free energy, heat, and work—are defined microscopically. These quantities obey thermodynamic relations including both the first and second law, and they satisfy nonequilibrium fluctuation theorems. We additionally impose a macroscopic consistency condition: When S is large, the quantities defined within our framework scale up to their macroscopic counterparts. By satisfying this condition, we demonstrate that a unifying framework can be developed, which encompasses both stochastic thermodynamics at one end, and macroscopic thermodynamics at the other. A central element in our approach is a thermodynamic definition of the volume of the system of interest, which converges to the usual geometric definition when S is large. We also sketch an alternative framework that satisfies the same consistency conditions. The dynamics of the system and environment are modeled using Hamilton’s equations in the full phase space.

  12. Macroscopic description of the limb muscles of Tupinambis merianae

    Directory of Open Access Journals (Sweden)

    Juliana Barbosa Casals

    2012-03-01

    Full Text Available Tegu lizard (Tupinambis merianae belongs to the Teiidae family. It is distributed throughout the Americas, with many species, including Brazilian ones. They are from the Tupinambis genus, the largest representatives of the Teiidae family. For this study three animals (run over coming from donation were used. The dissected lizards were fixed in 10%, formaldehyde, and the macroscopic analysis was carried out in a detailed and photo documented way, keeping the selected structures “in situ”. This paper had as its main aim contributing to the macroscopic description of the chest myology, as well as the thoracic and pelvic limbs of the lizard T. merianae. The results obtained from this research were compared to authors who have studied animals from the same Reptilia class. Thus, we conclude that our macroscopic results are similar to those already described by the researchers Hildebrand (1995, Moro and Abdala (2004 and Abdala and Diogo (2010. We should highlight that the knowledge on anatomy has importance and applications to various areas within Biology, contributing in a substantial way to the areas of human health and technology.

  13. Macroscopic electrical field distribution and field-induced surface stresses of needle-shaped field emitters

    Energy Technology Data Exchange (ETDEWEB)

    Moy, Charles K.S., E-mail: charles.moy@sydney.edu.au [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); ARC Centre of Excellence for Design in Light Metals, The University of Sydney, Sydney, NSW 2006 (Australia); School of Civil Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Ranzi, Gianluca [ARC Centre of Excellence for Design in Light Metals, The University of Sydney, Sydney, NSW 2006 (Australia); School of Civil Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Petersen, Timothy C. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); Ringer, Simon P. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); ARC Centre of Excellence for Design in Light Metals, The University of Sydney, Sydney, NSW 2006 (Australia)

    2011-05-15

    One major concern since the development of the field ion microscope is the mechanical strength of the specimens. The macroscopic shape of the imaging tip greatly influences field-induced stresses and there is merit in further study of this phenomenon from a classical perspective. Understanding the geometrical, as opposed to localized electronic, factors that affect the stress might improve the quality and success rate of atom probe experiments. This study uses macroscopic electrostatic principles and finite element modelling to investigate field-induced stresses in relation to the shape of the tip. Three two-dimensional idealized models are considered, namely hyperbolic, parabolic and sphere-on-orthogonal-cone; the shapes of which are compared to experimental tips prepared by electro-polishing. Three dimensional morphologies of both a nano-porous and single-crystal aluminium tip are measured using electron tomography to quantitatively test the assumption of cylindrical symmetry for electro-polished tips. The porous tip was prepared and studied to demonstrate a fragile specimen for which such finite element studies could determine potential mechanical failure, prior to any exhaustive atom probe investigation. -- Research highlights: {yields} We use electrostatic principles and finite element to model field-induced stresses. {yields} We study two-dimensional idealized needle-shaped field emitters. {yields} Stress distribution of hyperbolic, parabolic and sphere-on-orthogonal-cone tips mapped. {yields} Electron tomography to obtain the morphology of three-dimensional aluminium tips. {yields} Studies of the morphology of the porous tip demonstrate a fragile specimen.

  14. Microscopic and macroscopic models for the onset and progression of Alzheimer's disease

    International Nuclear Information System (INIS)

    Bertsch, Michiel; Franchi, Bruno; Tesi, Maria Carla; Tosin, Andrea

    2017-01-01

    In the first part of this paper we review a mathematical model for the onset and progression of Alzheimer’s disease (AD) that was developed in subsequent steps over several years. The model is meant to describe the evolution of AD in vivo . In Achdou et al (2013 J. Math. Biol . 67 1369–92) we treated the problem at a microscopic scale, where the typical length scale is a multiple of the size of the soma of a single neuron. Subsequently, in Bertsch et al (2017 Math. Med. Biol . 34 193–214) we concentrated on the macroscopic scale, where brain neurons are regarded as a continuous medium, structured by their degree of malfunctioning. In the second part of the paper we consider the relation between the microscopic and the macroscopic models. In particular we show under which assumptions the kinetic transport equation, which in the macroscopic model governs the evolution of the probability measure for the degree of malfunctioning of neurons, can be derived from a particle-based setting. The models are based on aggregation and diffusion equations for β -Amyloid (A β from now on), a protein fragment that healthy brains regularly produce and eliminate. In case of dementia A β monomers are no longer properly washed out and begin to coalesce forming eventually plaques. Two different mechanisms are assumed to be relevant for the temporal evolution of the disease: (i) diffusion and agglomeration of soluble polymers of amyloid, produced by damaged neurons; (ii) neuron-to-neuron prion-like transmission. In the microscopic model we consider mechanism (i), modelling it by a system of Smoluchowski equations for the amyloid concentration (describing the agglomeration phenomenon), with the addition of a diffusion term as well as of a source term on the neuronal membrane. At the macroscopic level instead we model processes (i) and (ii) by a system of Smoluchowski equations for the amyloid concentration, coupled to a kinetic-type transport equation for the distribution

  15. Microscopic and macroscopic models for the onset and progression of Alzheimer's disease

    Science.gov (United States)

    Bertsch, Michiel; Franchi, Bruno; Carla Tesi, Maria; Tosin, Andrea

    2017-10-01

    In the first part of this paper we review a mathematical model for the onset and progression of Alzheimer’s disease (AD) that was developed in subsequent steps over several years. The model is meant to describe the evolution of AD in vivo. In Achdou et al (2013 J. Math. Biol. 67 1369-92) we treated the problem at a microscopic scale, where the typical length scale is a multiple of the size of the soma of a single neuron. Subsequently, in Bertsch et al (2017 Math. Med. Biol. 34 193-214) we concentrated on the macroscopic scale, where brain neurons are regarded as a continuous medium, structured by their degree of malfunctioning. In the second part of the paper we consider the relation between the microscopic and the macroscopic models. In particular we show under which assumptions the kinetic transport equation, which in the macroscopic model governs the evolution of the probability measure for the degree of malfunctioning of neurons, can be derived from a particle-based setting. The models are based on aggregation and diffusion equations for β-Amyloid (Aβ from now on), a protein fragment that healthy brains regularly produce and eliminate. In case of dementia Aβ monomers are no longer properly washed out and begin to coalesce forming eventually plaques. Two different mechanisms are assumed to be relevant for the temporal evolution of the disease: (i) diffusion and agglomeration of soluble polymers of amyloid, produced by damaged neurons; (ii) neuron-to-neuron prion-like transmission. In the microscopic model we consider mechanism (i), modelling it by a system of Smoluchowski equations for the amyloid concentration (describing the agglomeration phenomenon), with the addition of a diffusion term as well as of a source term on the neuronal membrane. At the macroscopic level instead we model processes (i) and (ii) by a system of Smoluchowski equations for the amyloid concentration, coupled to a kinetic-type transport equation for the distribution function of the

  16. Micromechanical study of macroscopic friction and dissipation in idealised granular materials: the effect of interparticle friction

    NARCIS (Netherlands)

    Kruyt, Nicolaas P.; Gutkowski, Witold; Rothenburg, L.; Kowalewski, Tomasz A.

    2004-01-01

    Using Discrete Element Method (DEM) simulations with varying interparticle friction coefficient, the relation between interparticle friction coefficient and macroscopic continuum friction and dissipation is investigated. As expected, macroscopic friction and dilatancy increase with interparticle

  17. Macroscopic Quantum-Type Potentials in Theoretical Systems Biology

    Directory of Open Access Journals (Sweden)

    Laurent Nottale

    2013-12-01

    Full Text Available We review in this paper the use of the theory of scale relativity and fractal space-time as a tool particularly well adapted to the possible development of a future genuine systems theoretical biology. We emphasize in particular the concept of quantum-type potentials, since, in many situations, the effect of the fractality of space—or of the underlying medium—can be reduced to the addition of such a potential energy to the classical equations of motion. Various equivalent representations—geodesic, quantum-like, fluid mechanical, stochastic—of these equations are given, as well as several forms of generalized quantum potentials. Examples of their possible intervention in high critical temperature superconductivity and in turbulence are also described, since some biological processes may be similar in some aspects to these physical phenomena. These potential extra energy contributions could have emerged in biology from the very fractal nature of the medium, or from an evolutive advantage, since they involve spontaneous properties of self-organization, morphogenesis, structuration and multi-scale integration. Finally, some examples of applications of the theory to actual biological-like processes and functions are also provided.

  18. Microscopic origin and macroscopic implications of lane formation in mixtures of oppositely driven particles

    Science.gov (United States)

    Klymko, Katherine; Geissler, Phillip L.; Whitelam, Stephen

    2016-08-01

    Colloidal particles of two types, driven in opposite directions, can segregate into lanes [Vissers et al., Soft Matter 7, 2352 (2011), 10.1039/c0sm01343a]. This phenomenon can be reproduced by two-dimensional Brownian dynamics simulations of model particles [Dzubiella et al., Phys. Rev. E 65, 021402 (2002), 10.1103/PhysRevE.65.021402]. Here we use computer simulation to assess the generality of lane formation with respect to variation of particle type and dynamical protocol. We find that laning results from rectification of diffusion on the scale of a particle diameter: oppositely driven particles must, in the time taken to encounter each other in the direction of the drive, diffuse in the perpendicular direction by about one particle diameter. This geometric constraint implies that the diffusion constant of a particle, in the presence of those of the opposite type, grows approximately linearly with the Péclet number, a prediction confirmed by our numerics over a range of model parameters. Such environment-dependent diffusion is statistically similar to an effective interparticle attraction; consistent with this observation, we find that oppositely driven nonattractive colloids display features characteristic of the simplest model system possessing both interparticle attractions and persistent motion, the driven Ising lattice gas [Katz, Leibowitz, and Spohn, J. Stat. Phys. 34, 497 (1984), 10.1007/BF01018556]. These features include long-ranged correlations in the disordered regime, a critical regime characterized by a change in slope of the particle current with the Péclet number, and fluctuations that grow with system size. By analogy, we suggest that lane formation in the driven colloid system is a phase transition in the macroscopic limit, but that macroscopic phase separation would not occur in finite time upon starting from disordered initial conditions.

  19. Ultrahigh-Q mechanical oscillators through optical trapping

    International Nuclear Information System (INIS)

    Chang, D E; Ni, K-K; Painter, O; Kimble, H J

    2012-01-01

    Rapid advances are being made toward optically cooling a single mode of a micro-mechanical system to its quantum ground state and observing the quantum behavior at macroscopic scales. Reaching this regime in room-temperature environments requires a stringent condition on the mechanical quality factor Q m and frequency f m , Q m f m ≳ k B T bath /h, which so far has been marginally satisfied only in a small number of systems. Here we propose and analyze a new class of systems that should enable one to obtain unprecedented Q-frequency products. The technique is based on the use of optical forces to ‘trap’ and stiffen the motion of a tethered mechanical structure, thereby freeing the resulting mechanical frequencies and decoherence rates from the underlying material properties. (paper)

  20. Gecko toe and lamellar shear adhesion on macroscopic, engineered rough surfaces.

    Science.gov (United States)

    Gillies, Andrew G; Henry, Amy; Lin, Hauwen; Ren, Angela; Shiuan, Kevin; Fearing, Ronald S; Full, Robert J

    2014-01-15

    The role in adhesion of the toes and lamellae - intermediate-sized structures - found on the gecko foot remains unclear. Insight into the function of these structures can lead to a more general understanding of the hierarchical nature of the gecko adhesive system, but in particular how environmental topology may relate to gecko foot morphology. We sought to discern the mechanics of the toes and lamellae by examining gecko adhesion on controlled, macroscopically rough surfaces. We used live Tokay geckos, Gekko gecko, to observe the maximum shear force a gecko foot can attain on an engineered substrate constructed with sinusoidal patterns of varying amplitudes and wavelengths in sizes similar to the dimensions of the toes and lamellae structures (0.5 to 6 mm). We found shear adhesion was significantly decreased on surfaces that had amplitudes and wavelengths approaching the lamella length and inter-lamella spacing, losing 95% of shear adhesion over the range tested. We discovered that the toes are capable of adhering to surfaces with amplitudes much larger than their dimensions even without engaging claws, maintaining 60% of shear adhesion on surfaces with amplitudes of 3 mm. Gecko adhesion can be predicted by the ratio of the lamella dimensions to surface feature dimensions. In addition to setae, remarkable macroscopic-scale features of gecko toes and lamellae that include compliance and passive conformation are necessary to maintain contact, and consequently, generate shear adhesion on macroscopically rough surfaces. Findings on the larger scale structures in the hierarchy of gecko foot function could provide the biological inspiration to drive the design of more effective and versatile synthetic fibrillar adhesives.

  1. In regard to the question of macroscopic differential diagnosis of alcoholic and dilated cardiomyopathy

    Directory of Open Access Journals (Sweden)

    O. V. Sokolova

    2014-01-01

    Full Text Available The differential diagnosis of alcoholic and dilated cardiomyopathy according to the macroscopic data is represented in the article. The identity of macroscopic changes of heart, related to alcoholic and dilated cardiomyopathy, cannot diagnose these diseases based on the macroscopic characteristics; especially if there are no other visceral manifestations typical for chronic alcoholism.

  2. Finite element simulation of nanoindentation tests using a macroscopic computational model

    International Nuclear Information System (INIS)

    Khelifa, Mourad; Fierro, Vanessa; Celzard, Alain

    2014-01-01

    The aim of this work was to develop a numerical procedure to simulate nanoindentation tests using a macroscopic computational model. Both theoretical and numerical aspects of the proposed methodology, based on the coupling of isotropic elasticity and anisotropic plasticity described with the quadratic criterion of Hill are presented to model this behaviour. The anisotropic plastic behaviour accounts for the mixed nonlinear hardening (isotropic and kinematic) under large plastic deformation. Nanoindentation tests were simulated to analyse the nonlinear mechanical behaviour of aluminium alloy. The predicted results of the finite element (FE) modelling are in good agreement with the experimental data, thereby confirming the accuracy level of the suggested FE method of analysis. The effects of some technological and mechanical parameters known to have an influence during the nanoindentation tests were also investigated.

  3. Brain Activation by H1 Antihistamines Challenges Conventional View of Their Mechanism of Action in Motion Sickness: A Behavioral, c-Fos and Physiological Study in Suncus murinus (House Musk Shrew

    Directory of Open Access Journals (Sweden)

    Longlong Tu

    2017-06-01

    -fos in brain areas regulating emesis control, and caused hypothermia; it also appeared to cause sedation and reduced the dominant frequency of slow waves. In conclusion, motion-induced emesis was associated with a disruption of GMA, respiration, and hypothermia. Mepyramine was a more efficacious anti-emetic than cetirizine, suggesting an important role of centrally-located H1 receptors. The ability of mepyramine to elevate c-fos provides a new perspective on how H1 receptors are involved in mechanisms of emesis control.

  4. Macroscopic polarization in crystalline dielectrics: the geometric phase approach

    International Nuclear Information System (INIS)

    Resta, R.

    1994-01-01

    The macroscopic electric polarization of a crystal is often defined as the dipole of a unit cell. In fact, such a dipole moment is ill defined, and the above definition is incorrect. Looking more closely, the quantity generally measured is differential polarization, defined with respect to a ''reference state'' of the same material. Such differential polarizations include either derivatives of the polarization (dielectric permittivity, Born effective charges, piezoelectricity, pyroelectricity) or finite differences (ferroelectricity). On the theoretical side, the differential concept is basic as well. Owing to continuity, a polarization difference is equivalent to a macroscopic current, which is directly accessible to the theory as a bulk property. Polarization is a quantum phenomenon and cannot be treated with a classical model, particularly whenever delocalized valence electrons are present in the dielectric. In a quantum picture, the current is basically a property of the phase of the wave functions, as opposed to the charge, which is a property of their modulus. An elegant and complete theory has recently been developed by King-Smith and Vanderbilt, in which the polarization difference between any two crystal states--in a null electric field--takes the form of a geometric quantum phase. This gives a comprehensive account of this theory, which is relevant for dealing with transverse-optic phonons, piezoelectricity, and ferroelectricity. Its relation to the established concepts of linear-response theory is also discussed. Within the geometric phase approach, the relevant polarization difference occurs as the circuit integral of a Berry connection (or ''vector potential''), while the corresponding curvature (or ''magnetic field'') provides the macroscopic linear response

  5. Macroscopic influence on the spontaneous symmetry breaking in quantum field

    International Nuclear Information System (INIS)

    Kirzhnitz, D.A.

    1977-01-01

    Major results of investigations concerning macroscopic influence (heating, compression, external field and current) on elementary particle systems with spontaneous symmetry breaking are briefly reviewed. The study of this problem has been stimulated by recent progress in the unified renormalizable theory of elementary particles. Typically it appears that at some values of external parameters a phase transition with symmetry restoration takes place. There exists a profound and far going analogy with phase transition in many-body physics especially with superconductivity phenomenon. Some applications to cosmology are also considered

  6. Macroscopic relationship in primal-dual portfolio optimization problem

    Science.gov (United States)

    Shinzato, Takashi

    2018-02-01

    In the present paper, using a replica analysis, we examine the portfolio optimization problem handled in previous work and discuss the minimization of investment risk under constraints of budget and expected return for the case that the distribution of the hyperparameters of the mean and variance of the return rate of each asset are not limited to a specific probability family. Findings derived using our proposed method are compared with those in previous work to verify the effectiveness of our proposed method. Further, we derive a Pythagorean theorem of the Sharpe ratio and macroscopic relations of opportunity loss. Using numerical experiments, the effectiveness of our proposed method is demonstrated for a specific situation.

  7. Seismic scanning tunneling macroscope - Elastic simulations and Arizona mine test

    KAUST Repository

    Hanafy, Sherif M.; Schuster, Gerard T.

    2012-01-01

    Elastic seismic simulations and field data tests are used to validate the theory of a seismic scanning tunneling macroscope (SSTM). For nearfield elastic simulation, the SSTM results show superresolution to be better than λ/8 if the only scattered data are used as input data. If the direct P and S waves are muted then the resolution of the scatterer locations are within about λ/5. Seismic data collected in an Arizona tunnel showed a superresolution limit of at least λ/19. These test results are consistent with the theory of the SSTM and suggest that the SSTM can be a tool used by geophysicists as a probe for near-field scatterers.

  8. GRUCAL, a computer program for calculating macroscopic group constants

    International Nuclear Information System (INIS)

    Woll, D.

    1975-06-01

    Nuclear reactor calculations require material- and composition-dependent, energy averaged nuclear data to describe the interaction of neutrons with individual isotopes in material compositions of reactor zones. The code GRUCAL calculates these macroscopic group constants for given compositions from the material-dependent data of the group constant library GRUBA. The instructions for calculating group constants are not fixed in the program, but will be read at the actual execution time from a separate instruction file. This allows to accomodate GRUCAL to various problems or different group constant concepts. (orig.) [de

  9. Conductance fluctuations in a macroscopic 3-dimensional Anderson insulator

    International Nuclear Information System (INIS)

    Sanquer, M.

    1990-01-01

    We report magnetoconductance experiment on a amorphous Y x -Si 1-x alloy (∼0.3). which is an Anderson insulator where spin-orbit scattering is strong. Two principal and new features emerge from the data: the first one is an halving of the localization length by the application of a magnetic field of about 2.5 Teslas. This effect is predicted by a new approach of transport in Anderson insulators where basic symetry considerations are the most important ingredient. The second one is the observation of reproducible conductance fluctuations at very low temperature in this macroscopic 3 D amorphous material

  10. A simple vibrating sample magnetometer for macroscopic samples

    Science.gov (United States)

    Lopez-Dominguez, V.; Quesada, A.; Guzmán-Mínguez, J. C.; Moreno, L.; Lere, M.; Spottorno, J.; Giacomone, F.; Fernández, J. F.; Hernando, A.; García, M. A.

    2018-03-01

    We here present a simple model of a vibrating sample magnetometer (VSM). The system allows recording magnetization curves at room temperature with a resolution of the order of 0.01 emu and is appropriated for macroscopic samples. The setup can be mounted with different configurations depending on the requirements of the sample to be measured (mass, saturation magnetization, saturation field, etc.). We also include here examples of curves obtained with our setup and comparison curves measured with a standard commercial VSM that confirms the reliability of our device.

  11. Quantum Darwinism in Quantum Brownian Motion

    Science.gov (United States)

    Blume-Kohout, Robin; Zurek, Wojciech H.

    2008-12-01

    Quantum Darwinism—the redundant encoding of information about a decohering system in its environment—was proposed to reconcile the quantum nature of our Universe with apparent classicality. We report the first study of the dynamics of quantum Darwinism in a realistic model of decoherence, quantum Brownian motion. Prepared in a highly squeezed state—a macroscopic superposition—the system leaves records whose redundancy increases rapidly with initial delocalization. Redundancy appears rapidly (on the decoherence time scale) and persists for a long time.

  12. Evolution of the Contact Area with Normal Load for Rough Surfaces: from Atomic to Macroscopic Scales.

    Science.gov (United States)

    Huang, Shiping

    2017-11-13

    The evolution of the contact area with normal load for rough surfaces has great fundamental and practical importance, ranging from earthquake dynamics to machine wear. This work bridges the gap between the atomic scale and the macroscopic scale for normal contact behavior. The real contact area, which is formed by a large ensemble of discrete contacts (clusters), is proven to be much smaller than the apparent surface area. The distribution of the discrete contact clusters and the interaction between them are key to revealing the mechanism of the contacting solids. To this end, Green's function molecular dynamics (GFMD) is used to study both how the contact cluster evolves from the atomic scale to the macroscopic scale and the interaction between clusters. It is found that the interaction between clusters has a strong effect on their formation. The formation and distribution of the contact clusters is far more complicated than that predicted by the asperity model. Ignorance of the interaction between them leads to overestimating the contacting force. In real contact, contacting clusters are smaller and more discrete due to the interaction between the asperities. Understanding the exact nature of the contact area with the normal load is essential to the following research on friction.

  13. Electricity in foams: from one soapy interface to the macroscopic material

    Science.gov (United States)

    Biance, Anne-Laure

    2017-11-01

    Liquid foams (a dispersion of gas bubbles in a soapy solution) destabilize with time due to coarsening, coalescence and gravity driven drainage. We propose here to inhibit (or trigger) the foam destabilization by applying an electric field to the material. This effect is investigated at the different scales of the system: one soapy interface, one liquid film, the macroscopic foam. The generation of an electroosmotic flow near a soapy liquid/gas interface raises many issues. How does the flow affect surfactant repartition? Is there a Marangoni stress at the interface? At the scale of one soap film, how the electric field affects the film stability and deformation? In a macroscopic foam, one can wonder whether the electric field can indeed reverse gravity driven drainage and increase foam lifetime? These different issues are considered by developing new experimental techniques allowing us to probe surfactant repartition at liquid interfaces, soap film thicknesses and liquid foam properties when an electric field is applied. The results will be presented together with a comprehensive picture of the mechanisms arising at each scale of the material, to conclude with the potential use of electricity in liquid foams to control destabilization. Collaborators: Baptiste Blanc, Oriane Bonhomme, Laurent Joly, Christophe Ybert.

  14. Time-dependent entropy evolution in microscopic and macroscopic electromagnetic relaxation

    International Nuclear Information System (INIS)

    Baker-Jarvis, James

    2005-01-01

    This paper is a study of entropy and its evolution in the time and frequency domains upon application of electromagnetic fields to materials. An understanding of entropy and its evolution in electromagnetic interactions bridges the boundaries between electromagnetism and thermodynamics. The approach used here is a Liouville-based statistical-mechanical theory. I show that the microscopic entropy is reversible and the macroscopic entropy satisfies an H theorem. The spectral entropy development can be very useful for studying the frequency response of materials. Using a projection-operator based nonequilibrium entropy, different equations are derived for the entropy and entropy production and are applied to the polarization, magnetization, and macroscopic fields. I begin by proving an exact H theorem for the entropy, progress to application of time-dependent entropy in electromagnetics, and then apply the theory to relevant applications in electromagnetics. The paper concludes with a discussion of the relationship of the frequency-domain form of the entropy to the permittivity, permeability, and impedance

  15. Biomechanical and biophysical environment of bone from the macroscopic to the pericellular and molecular level.

    Science.gov (United States)

    Ren, Li; Yang, Pengfei; Wang, Zhe; Zhang, Jian; Ding, Chong; Shang, Peng

    2015-10-01

    Bones with complicated hierarchical configuration and microstructures constitute the load-bearing system. Mechanical loading plays an essential role in maintaining bone health and regulating bone mechanical adaptation (modeling and remodeling). The whole-bone or sub-region (macroscopic) mechanical signals, including locomotion-induced loading and external actuator-generated vibration, ultrasound, oscillatory skeletal muscle stimulation, etc., give rise to sophisticated and distinct biomechanical and biophysical environments at the pericellular (microscopic) and collagen/mineral molecular (nanoscopic) levels, which are the direct stimulations that positively influence bone adaptation. While under microgravity, the stimulations decrease or even disappear, which exerts a negative influence on bone adaptation. A full understanding of the biomechanical and biophysical environment at different levels is necessary for exploring bone biomechanical properties and mechanical adaptation. In this review, the mechanical transferring theories from the macroscopic to the microscopic and nanoscopic levels are elucidated. First, detailed information of the hierarchical structures and biochemical composition of bone, which are the foundations for mechanical signal propagation, are presented. Second, the deformation feature of load-bearing bone during locomotion is clarified as a combination of bending and torsion rather than simplex bending. The bone matrix strains at microscopic and nanoscopic levels directly induced by bone deformation are critically discussed, and the strain concentration mechanism due to the complicated microstructures is highlighted. Third, the biomechanical and biophysical environments at microscopic and nanoscopic levels positively generated during bone matrix deformation or by dynamic mechanical loadings induced by external actuators, as well as those negatively affected under microgravity, are systematically discussed, including the interstitial fluid flow

  16. Comparative Study on Interaction of Form and Motion Processing Streams by Applying Two Different Classifiers in Mechanism for Recognition of Biological Movement

    Science.gov (United States)

    2014-01-01

    Research on psychophysics, neurophysiology, and functional imaging shows particular representation of biological movements which contains two pathways. The visual perception of biological movements formed through the visual system called dorsal and ventral processing streams. Ventral processing stream is associated with the form information extraction; on the other hand, dorsal processing stream provides motion information. Active basic model (ABM) as hierarchical representation of the human object had revealed novelty in form pathway due to applying Gabor based supervised object recognition method. It creates more biological plausibility along with similarity with original model. Fuzzy inference system is used for motion pattern information in motion pathway creating more robustness in recognition process. Besides, interaction of these paths is intriguing and many studies in various fields considered it. Here, the interaction of the pathways to get more appropriated results has been investigated. Extreme learning machine (ELM) has been implied for classification unit of this model, due to having the main properties of artificial neural networks, but crosses from the difficulty of training time substantially diminished in it. Here, there will be a comparison between two different configurations, interactions using synergetic neural network and ELM, in terms of accuracy and compatibility. PMID:25276860

  17. Comparative Study on Interaction of Form and Motion Processing Streams by Applying Two Different Classifiers in Mechanism for Recognition of Biological Movement

    Directory of Open Access Journals (Sweden)

    Bardia Yousefi

    2014-01-01

    Full Text Available Research on psychophysics, neurophysiology, and functional imaging shows particular representation of biological movements which contains two pathways. The visual perception of biological movements formed through the visual system called dorsal and ventral processing streams. Ventral processing stream is associated with the form information extraction; on the other hand, dorsal processing stream provides motion information. Active basic model (ABM as hierarchical representation of the human object had revealed novelty in form pathway due to applying Gabor based supervised object recognition method. It creates more biological plausibility along with similarity with original model. Fuzzy inference system is used for motion pattern information in motion pathway creating more robustness in recognition process. Besides, interaction of these paths is intriguing and many studies in various fields considered it. Here, the interaction of the pathways to get more appropriated results has been investigated. Extreme learning machine (ELM has been implied for classification unit of this model, due to having the main properties of artificial neural networks, but crosses from the difficulty of training time substantially diminished in it. Here, there will be a comparison between two different configurations, interactions using synergetic neural network and ELM, in terms of accuracy and compatibility.

  18. Auditory Motion Elicits a Visual Motion Aftereffect

    Directory of Open Access Journals (Sweden)

    Christopher C. Berger

    2016-12-01

    Full Text Available The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect—an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

  19. Auditory Motion Elicits a Visual Motion Aftereffect.

    Science.gov (United States)

    Berger, Christopher C; Ehrsson, H Henrik

    2016-01-01

    The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect-an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

  20. Auditory motion capturing ambiguous visual motion

    Directory of Open Access Journals (Sweden)

    Arjen eAlink

    2012-01-01

    Full Text Available In this study, it is demonstrated that moving sounds have an effect on the direction in which one sees visual stimuli move. During the main experiment sounds were presented consecutively at four speaker locations inducing left- or rightwards auditory apparent motion. On the path of auditory apparent motion, visual apparent motion stimuli were presented with a high degree of directional ambiguity. The main outcome of this experiment is that our participants perceived visual apparent motion stimuli that were ambiguous (equally likely to be perceived as moving left- or rightwards more often as moving in the same direction than in the opposite direction of auditory apparent motion. During the control experiment we replicated this finding and found no effect of sound motion direction on eye movements. This indicates that auditory motion can capture our visual motion percept when visual motion direction is insufficiently determinate without affecting eye movements.

  1. Continuum Mechanics

    CERN Document Server

    Romano, Antonio

    2010-01-01

    This book offers a broad overview of the potential of continuum mechanics to describe a wide range of macroscopic phenomena in real-world problems. Building on the fundamentals presented in the authors' previous book, Continuum Mechanics using Mathematica(R), this new work explores interesting models of continuum mechanics, with an emphasis on exploring the flexibility of their applications in a wide variety of fields.Specific topics, which have been chosen to show the power of continuum mechanics to characterize the experimental behavior of real phenomena, include: * various aspects of nonlin

  2. Macroscopic superposition states and decoherence by quantum telegraph noise

    Energy Technology Data Exchange (ETDEWEB)

    Abel, Benjamin Simon

    2008-12-19

    In the first part of the present thesis we address the question about the size of superpositions of macroscopically distinct quantum states. We propose a measure for the ''size'' of a Schroedinger cat state, i.e. a quantum superposition of two many-body states with (supposedly) macroscopically distinct properties, by counting how many single-particle operations are needed to map one state onto the other. We apply our measure to a superconducting three-junction flux qubit put into a superposition of clockwise and counterclockwise circulating supercurrent states and find this Schroedinger cat to be surprisingly small. The unavoidable coupling of any quantum system to many environmental degrees of freedom leads to an irreversible loss of information about an initially prepared superposition of quantum states. This phenomenon, commonly referred to as decoherence or dephasing, is the subject of the second part of the thesis. We have studied the time evolution of the reduced density matrix of a two-level system (qubit) subject to quantum telegraph noise which is the major source of decoherence in Josephson charge qubits. We are able to derive an exact expression for the time evolution of the reduced density matrix. (orig.)

  3. An exploration for the macroscopic physical meaning of entropy

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The macroscopic physical meaning of entropy is analyzed based on the exergy (availability) of a combined system (a closed system and its environment), which is the maximum amount of useful work obtainable from the system and the environment as the system is brought into equilibrium with the environment. The process the system experiences can be divided in two sequent sub-processes, the process at constant volume, which represents the heat interaction of the system with the environment, and the adiabatic process, which represents the work interaction of the system with the environment. It is shown that the macroscopic physical meaning of entropy is a measure of the unavailable energy of a closed system for doing useful work through heat interaction. This statement is more precise than those reported in prior literature. The unavailability function of a closed system can be defined as T0S and p0V in volume constant process and adiabatic process, respectively. Their changes, that is, AiTgS) and A (p0V) represent the unusable parts of the internal energy of a closed system for doing useful work in corresponding processes. Finally, the relation between Clausius entropy and Boltzmann entropy is discussed based on the comparison of their expressions for absolute entropy.

  4. Macroscopic Theory for Evolving Biological Systems Akin to Thermodynamics.

    Science.gov (United States)

    Kaneko, Kunihiko; Furusawa, Chikara

    2018-05-20

    We present a macroscopic theory to characterize the plasticity, robustness, and evolvability of biological responses and their fluctuations. First, linear approximation in intracellular reaction dynamics is used to demonstrate proportional changes in the expression of all cellular components in response to a given environmental stress, with the proportion coefficient determined by the change in growth rate as a consequence of the steady growth of cells. We further demonstrate that this relationship is supported through adaptation experiments of bacteria, perhaps too well as this proportionality is held even across cultures of different types of conditions. On the basis of simulations of cell models, we further show that this global proportionality is a consequence of evolution in which expression changes in response to environmental or genetic perturbations are constrained along a unique one-dimensional curve, which is a result of evolutionary robustness. It then follows that the expression changes induced by environmental changes are proportionally reduced across different components of a cell by evolution, which is akin to the Le Chatelier thermodynamics principle. Finally, with the aid of a fluctuation-response relationship, this proportionality is shown to hold between fluctuations caused by genetic changes and those caused by noise. Overall, these results and support from the theoretical and experimental literature suggest a formulation of cellular systems akin to thermodynamics, in which a macroscopic potential is given by the growth rate (or fitness) represented as a function of environmental and evolutionary changes.

  5. Parametric equations for calculation of macroscopic cross sections

    International Nuclear Information System (INIS)

    Botelho, Mario Hugo; Carvalho, Fernando

    2015-01-01

    Neutronic calculations of the core of a nuclear reactor is one thing necessary and important for the design and management of a nuclear reactor in order to prevent accidents and control the reactor efficiently as possible. To perform these calculations a library of nuclear data, including cross sections is required. Currently, to obtain a cross section computer codes are used, which require a large amount of processing time and computer memory. This paper proposes the calculation of macroscopic cross section through the development of parametric equations. The paper illustrates the proposal for the case of macroscopic cross sections of absorption (Σa), which was chosen due to its greater complexity among other cross sections. Parametric equations created enable, quick and dynamic way, the determination of absorption cross sections, enabling the use of them in calculations of reactors. The results show efficient when compared with the absorption cross sections obtained by the ALPHA 8.8.1 code. The differences between the cross sections are less than 2% for group 2 and less than 0.60% for group 1. (author)

  6. A Macroscopic Multifractal Analysis of Parabolic Stochastic PDEs

    Science.gov (United States)

    Khoshnevisan, Davar; Kim, Kunwoo; Xiao, Yimin

    2018-05-01

    It is generally argued that the solution to a stochastic PDE with multiplicative noise—such as \\dot{u}= 1/2 u''+uξ, where {ξ} denotes space-time white noise—routinely produces exceptionally-large peaks that are "macroscopically multifractal." See, for example, Gibbon and Doering (Arch Ration Mech Anal 177:115-150, 2005), Gibbon and Titi (Proc R Soc A 461:3089-3097, 2005), and Zimmermann et al. (Phys Rev Lett 85(17):3612-3615, 2000). A few years ago, we proved that the spatial peaks of the solution to the mentioned stochastic PDE indeed form a random multifractal in the macroscopic sense of Barlow and Taylor (J Phys A 22(13):2621-2626, 1989; Proc Lond Math Soc (3) 64:125-152, 1992). The main result of the present paper is a proof of a rigorous formulation of the assertion that the spatio-temporal peaks of the solution form infinitely-many different multifractals on infinitely-many different scales, which we sometimes refer to as "stretch factors." A simpler, though still complex, such structure is shown to also exist for the constant-coefficient version of the said stochastic PDE.

  7. Parameterized representation of macroscopic cross section for PWR reactor

    International Nuclear Information System (INIS)

    Fiel, João Cláudio Batista; Carvalho da Silva, Fernando; Senra Martinez, Aquilino; Leal, Luiz C.

    2015-01-01

    Highlights: • This work describes a parameterized representation of the homogenized macroscopic cross section for PWR reactor. • Parameterization enables a quick determination of problem-dependent cross-sections to be used in few group calculations. • This work allows generating group cross-section data to perform PWR core calculations without computer code calculations. - Abstract: The purpose of this work is to describe, by means of Chebyshev polynomials, a parameterized representation of the homogenized macroscopic cross section for PWR fuel element as a function of soluble boron concentration, moderator temperature, fuel temperature, moderator density and 235 92 U enrichment. The cross-section data analyzed are fission, scattering, total, transport, absorption and capture. The parameterization enables a quick and easy determination of problem-dependent cross-sections to be used in few group calculations. The methodology presented in this paper will allow generation of group cross-section data from stored polynomials to perform PWR core calculations without the need to generate them based on computer code calculations using standard steps. The results obtained by the proposed methodology when compared with results from the SCALE code calculations show very good agreement

  8. Macroscopic Biological Characteristics of Individualized Therapy in Chinese Mongolian Osteopathy

    Science.gov (United States)

    Namula, Zhao; Mei, Wang; Li, Xue-en

    Objective: Chinese Mongolian osteopathy has been passed down from ancient times and includes unique practices and favorable efficacy. In this study, we investigate the macroscopic biological characteristics of individualized Chinese Mongolian osteopathy, in order to provide new principle and methods for the treatment of bone fracture. Method: With a view to provide a vital link between nature and humans, the four stages of Chinese Mongolian osteopathy focus on the unity of the mind and body, the limbs and body organs, the body and its functions, and humans and nature. Results: We discuss the merits of individualized osteopathy in terms of the underlying concepts, and evaluate the approaches and principles of traditional medicine, as well as biomechanics. Conclusions: Individualized Mongolian osteopathy targets macroscopic biological components including dynamic reduction, natural fixation, and functional healing. Chinese Mongolian osteopathy is a natural, ecological and non-invasive osteopathy that values the link between nature and humans, including the unity of mind and body. The biological components not only serve as a foundation for Chinese Mongolian osteopathy but are also important for the future development of modern osteopathy, focusing on individualization, actualization and integration.

  9. Macroscopic superposition states and decoherence by quantum telegraph noise

    International Nuclear Information System (INIS)

    Abel, Benjamin Simon

    2008-01-01

    In the first part of the present thesis we address the question about the size of superpositions of macroscopically distinct quantum states. We propose a measure for the ''size'' of a Schroedinger cat state, i.e. a quantum superposition of two many-body states with (supposedly) macroscopically distinct properties, by counting how many single-particle operations are needed to map one state onto the other. We apply our measure to a superconducting three-junction flux qubit put into a superposition of clockwise and counterclockwise circulating supercurrent states and find this Schroedinger cat to be surprisingly small. The unavoidable coupling of any quantum system to many environmental degrees of freedom leads to an irreversible loss of information about an initially prepared superposition of quantum states. This phenomenon, commonly referred to as decoherence or dephasing, is the subject of the second part of the thesis. We have studied the time evolution of the reduced density matrix of a two-level system (qubit) subject to quantum telegraph noise which is the major source of decoherence in Josephson charge qubits. We are able to derive an exact expression for the time evolution of the reduced density matrix. (orig.)

  10. Inverted rank distributions: Macroscopic statistics, universality classes, and critical exponents

    Science.gov (United States)

    Eliazar, Iddo; Cohen, Morrel H.

    2014-01-01

    An inverted rank distribution is an infinite sequence of positive sizes ordered in a monotone increasing fashion. Interlacing together Lorenzian and oligarchic asymptotic analyses, we establish a macroscopic classification of inverted rank distributions into five “socioeconomic” universality classes: communism, socialism, criticality, feudalism, and absolute monarchy. We further establish that: (i) communism and socialism are analogous to a “disordered phase”, feudalism and absolute monarchy are analogous to an “ordered phase”, and criticality is the “phase transition” between order and disorder; (ii) the universality classes are characterized by two critical exponents, one governing the ordered phase, and the other governing the disordered phase; (iii) communism, criticality, and absolute monarchy are characterized by sharp exponent values, and are inherently deterministic; (iv) socialism is characterized by a continuous exponent range, is inherently stochastic, and is universally governed by continuous power-law statistics; (v) feudalism is characterized by a continuous exponent range, is inherently stochastic, and is universally governed by discrete exponential statistics. The results presented in this paper yield a universal macroscopic socioeconophysical perspective of inverted rank distributions.

  11. A Macroscopic Multifractal Analysis of Parabolic Stochastic PDEs

    Science.gov (United States)

    Khoshnevisan, Davar; Kim, Kunwoo; Xiao, Yimin

    2018-04-01

    It is generally argued that the solution to a stochastic PDE with multiplicative noise—such as \\dot{u}= 1/2 u''+uξ, where {ξ} denotes space-time white noise—routinely produces exceptionally-large peaks that are "macroscopically multifractal." See, for example, Gibbon and Doering (Arch Ration Mech Anal 177:115-150, 2005), Gibbon and Titi (Proc R Soc A 461:3089-3097, 2005), and Zimmermann et al. (Phys Rev Lett 85(17):3612-3615, 2000). A few years ago, we proved that the spatial peaks of the solution to the mentioned stochastic PDE indeed form a random multifractal in the macroscopic sense of Barlow and Taylor (J Phys A 22(13):2621-2626, 1989; Proc Lond Math Soc (3) 64:125-152, 1992). The main result of the present paper is a proof of a rigorous formulation of the assertion that the spatio-temporal peaks of the solution form infinitely-many different multifractals on infinitely-many different scales, which we sometimes refer to as "stretch factors." A simpler, though still complex, such structure is shown to also exist for the constant-coefficient version of the said stochastic PDE.

  12. Logical reformulation of quantum mechanics. IV. Projectors in semiclassical physics

    International Nuclear Information System (INIS)

    Omnes, R.

    1989-01-01

    This is a technical paper providing the proofs of three useful theorems playing a central role in two kinds of physical applications: an explicit logical and mathematical formulation of the interpretation of quantum mechanics and the corresponding description of irreversibility. The Appendix contains a brief mathematical introduction to microlocal analysis. Three theorems are derived in the text: (A) Associating a projector in Hilbert space with a macroscopic regular cell in classical phase space. (B) Specifying the algebra of the projectors associated with different cells. (C) Showing the connection between the classical motion of cells and the Schroedinger evolution of projectors for a class of regular Hamiltonians corresponding approximately to deterministic systems as described within the framework of quantum mechanics. Applications to the interpretation of quantum mechanics are given and the consequences for irreversibility will be given later

  13. Motion control report

    CERN Document Server

    2013-01-01

    Please note this is a short discount publication. In today's manufacturing environment, Motion Control plays a major role in virtually every project.The Motion Control Report provides a comprehensive overview of the technology of Motion Control:* Design Considerations* Technologies* Methods to Control Motion* Examples of Motion Control in Systems* A Detailed Vendors List

  14. Controlling vortex motion and vortex kinetic friction

    International Nuclear Information System (INIS)

    Nori, Franco; Savel'ev, Sergey

    2006-01-01

    We summarize some recent results of vortex motion control and vortex kinetic friction. (1) We describe a device [J.E. Villegas, S. Savel'ev, F. Nori, E.M. Gonzalez, J.V. Anguita, R. Garcia, J.L. Vicent, Science 302 (2003) 1188] that can easily control the motion of flux quanta in a Niobium superconducting film on an array of nanoscale triangular magnets. Even though the input ac current has zero average, the resulting net motion of the vortices can be directed along either one direction, the opposite direction, or producing zero net motion. We also consider layered strongly anisotropic superconductors, with no fixed spatial asymmetry, and show [S. Savel'ev, F. Nori, Nature Materials 1 (2002) 179] how, with asymmetric drives, the ac motion of Josephson and/or pancake vortices can provide a net dc vortex current. (2) In analogy with the standard macroscopic friction, we present [A. Maeda, Y. Inoue, H. Kitano, S. Savel'ev, S. Okayasu, I. Tsukada, F. Nori , Phys. Rev. Lett. 94 (2005) 077001] a comparative study of the friction force felt by vortices in superconductors and charge density waves

  15. Controlling vortex motion and vortex kinetic friction

    Science.gov (United States)

    Nori, Franco; Savel'ev, Sergey

    2006-05-01

    We summarize some recent results of vortex motion control and vortex kinetic friction. (1) We describe a device [J.E. Villegas, S. Savel'ev, F. Nori, E.M. Gonzalez, J.V. Anguita, R. Garcìa, J.L. Vicent, Science 302 (2003) 1188] that can easily control the motion of flux quanta in a Niobium superconducting film on an array of nanoscale triangular magnets. Even though the input ac current has zero average, the resulting net motion of the vortices can be directed along either one direction, the opposite direction, or producing zero net motion. We also consider layered strongly anisotropic superconductors, with no fixed spatial asymmetry, and show [S. Savel'ev, F. Nori, Nature Materials 1 (2002) 179] how, with asymmetric drives, the ac motion of Josephson and/or pancake vortices can provide a net dc vortex current. (2) In analogy with the standard macroscopic friction, we present [A. Maeda, Y. Inoue, H. Kitano, S. Savel'ev, S. Okayasu, I. Tsukada, F. Nori , Phys. Rev. Lett. 94 (2005) 077001] a comparative study of the friction force felt by vortices in superconductors and charge density waves.

  16. Direct design of an energy landscape with bistable DNA origami mechanisms.

    Science.gov (United States)

    Zhou, Lifeng; Marras, Alexander E; Su, Hai-Jun; Castro, Carlos E

    2015-03-11

    Structural DNA nanotechnology provides a feasible technique for the design and fabrication of complex geometries even exhibiting controllable dynamic behavior. Recently we have demonstrated the possibility of implementing macroscopic engineering design approaches to construct DNA origami mechanisms (DOM) with programmable motion and tunable flexibility. Here, we implement the design of compliant DNA origami mechanisms to extend from prescribing motion to prescribing an energy landscape. Compliant mechanisms facilitate motion via deformation of components with tunable stiffness resulting in well-defined mechanical energy stored in the structure. We design, fabricate, and characterize a DNA origami nanostructure with an energy landscape defined by two stable states (local energy minima) separated by a designed energy barrier. This nanostructure is a four-bar bistable mechanism with two undeformed states. Traversing between those states requires deformation, and hence mechanical energy storage, in a compliant arm of the linkage. The energy barrier for switching between two states was obtained from the conformational distribution based on a Boltzmann probability function and closely follows a predictive mechanical model. Furthermore, we demonstrated the ability to actuate the mechanism into one stable state via additional DNA inputs and then release the actuation via DNA strand displacement. This controllable multistate system establishes a foundation for direct design of energy landscapes that regulate conformational dynamics similar to biomolecular complexes.

  17. Micro-finite-element method to assess elastic properties of trabecular bone at micro- and macroscopic level.

    Science.gov (United States)

    Rieger, R; Auregan, J C; Hoc, T

    2018-03-01

    The objective of the present study is to assess the mechanical behavior of trabecular bone based on microCT imaging and micro-finite-element analysis. In this way two methods are detailed: (i) direct determination of macroscopic elastic property of trabecular bone; (ii) inverse approach to assess mechanical properties of trabecular bone tissue. Thirty-five females and seven males (forty-two subjects) mean aged (±SD) 80±11.7 years from hospitals of Assistance publique-Hôpitaux de Paris (AP-HP) diagnosed with osteoporosis following a femoral neck fracture due to a fall from standing were included in this study. Fractured heads were collected during hip replacement surgery. Standardized bone cores were removed from the femoral head's equator by a trephine in a water bath. MicroCT images acquisition and analysis were performed with CTan ® software and bone volume fraction was then determined. Micro-finite-element simulations were per-formed using Abaqus 6.9-2 ® software in order to determine the macroscopic mechanical behaviour of the trabecular bone. After microCT acquisition, a longitudinal compression test was performed and the experimental macroscopic Young's Modulus was extracted. An inverse approach based on the whole trabecular bone's mechanical response and micro-finite-element analysis was performed to determine microscopic mechanical properties of trabecular bone. In the present study, elasticity of the tissue was shown to be similar to that of healthy tissue but with a lower yield stress. Classical histomorphometric analysis form microCT imaging associated with an inverse micro-finite-element method allowed to assess microscopic mechanical trabecular bone parameters. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  18. Fracture mechanics

    International Nuclear Information System (INIS)

    Miannay, D.P.

    1995-01-01

    This book entitle ''Fracture Mechanics'', the first one of the monograph ''Materiologie'' is geared to design engineers, material engineers, non destructive inspectors and safety experts. This book covers fracture mechanics in isotropic homogeneous continuum. Only the monotonic static loading is considered. This book intended to be a reference with the current state of the art gives the fundamental of the issues under concern and avoids the developments too complicated or not yet mastered for not making reading cumbersome. The subject matter is organized as going from an easy to a more complicated level and thus follows the chronological evolution in the field. Similarly the microscopic scale is considered before the macroscopic scale, the physical understanding of phenomena linked to the experimental observation of the material preceded the understanding of the macroscopic behaviour of structures. In this latter field the relatively recent contribution of finite element computations with some analogy with the experimental observation is determining. However more sensitive analysis is not skipped

  19. Stochastic mechanism of symmetry breaking

    International Nuclear Information System (INIS)

    Baseyan, H.Z.

    1983-01-01

    A new symmetry breaking mechanism conditioned by presence of random fields in vacuum is proposed. Massive Yang-Mills fields finally arise, that may be interpreted as ''macroscopic'' manifestation of the ''microscopic'' Yang-Mills massless theory

  20. Probing the surface properties of a polymer glass with macroscopic friction

    International Nuclear Information System (INIS)

    Bureau, Lionel

    2007-01-01

    We show how macroscopic friction can be used as a sensitive probe of chain dynamics at the surface of a glassy polymer. We present experiments in which a smooth poly(methylmethacrylate) (PMMA) solid slides on flat surfaces presenting different densities of pinning sites available for polymer/substrate bond formation. These experiments indicate that: (i) at high pinning level, frictional dissipation occurs through the sudden flips of molecular-sized bistable regions localized in a nm-thick layer of confined chains, which responds to shear as an elasto-plastic solid, and (ii) in situations of weak pinning, dissipation appears to be governed by a process akin to that proposed for rubber friction. This suggests that some 'glass-to-rubber' transition occurs at the polymer surface when its interaction with the substrate goes from strong to weak. The temperature-dependence of friction provides further support for the presence of a nm-thick layer at the polymer surface, which exhibits a rubberlike response in situation of weak interaction with the countersurface. This behavior results from the interplay between viscous flow in this surface layer, and shear induced depinning of adsorbed surface chains. Moreover, a quantitative analysis of the results indicates that the pinning dynamics of polymer chains is controlled by localized β rotational motions at the interface

  1. Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

    International Nuclear Information System (INIS)

    Cleland, A.N.

    1991-01-01

    Experiments investigated the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very-small-capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson-phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters. The experiments on small-capacitance tunnel junctions extend the measurements on the large-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wave function has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias

  2. Obtaining macroscopic quantities for the contact line problem from Density Functional Theory using asymptotic methods

    Science.gov (United States)

    Sibley, David; Nold, Andreas; Kalliadasis, Serafim

    2015-11-01

    Density Functional Theory (DFT), a statistical mechanics of fluids approach, captures microscopic details of the fluid density structure in the vicinity of contact lines, as seen in computations in our recent study. Contact lines describe the location where interfaces between two fluids meet solid substrates, and have stimulated a wealth of research due to both their ubiquity in nature and technological applications and also due to their rich multiscale behaviour. Whilst progress can be made computationally to capture the microscopic to mesoscopic structure from DFT, complete analytical results to fully bridge to the macroscale are lacking. In this work, we describe our efforts to bring asymptotic methods to DFT to obtain results for contact angles and other macroscopic quantities in various parameter regimes. We acknowledge financial support from European Research Council via Advanced Grant No. 247031.

  3. Build-up of macroscopic eigenstates in a memory-based constrained system

    International Nuclear Information System (INIS)

    Labousse, M; Perrard, S; Couder, Y; Fort, E

    2014-01-01

    A bouncing drop and its associated accompanying wave forms a walker. Based on previous works, we show in this article that it is possible to formulate a simple theoretical framework for the walker dynamics. It relies on a time scale decomposition corresponding to the effects successively generated when the memory effects increase. While the short time scale effect is simply responsible for the walker's propulsion, the intermediate scale generates spontaneously pivotal structures endowed with angular momentum. At an even larger memory scale, if the walker is spatially confined, the pivots become the building blocks of a self-organization into a global structure. This new theoretical framework is applied in the presence of an external harmonic potential, and reveals the underlying mechanisms leading to the emergence of the macroscopic spatial organization reported by Perrard et al (2014 Nature Commun. 5 3219). (paper)

  4. Study of n-Butyl Acrylate Self-Initiation Reaction Experimentally and via Macroscopic Mechanistic Modeling

    Directory of Open Access Journals (Sweden)

    Ahmad Arabi Shamsabadi

    2016-04-01

    Full Text Available This paper presents an experimental study of the self-initiation reaction of n-butyl acrylate (n-BA in free-radical polymerization. For the first time, the frequency factor and activation energy of the monomer self-initiation reaction are estimated from measurements of n-BA conversion in free-radical homo-polymerization initiated only by the monomer. The estimation was carried out using a macroscopic mechanistic mathematical model of the reactor. In addition to already-known reactions that contribute to the polymerization, the model considers a n-BA self-initiation reaction mechanism that is based on our previous electronic-level first-principles theoretical study of the self-initiation reaction. Reaction rate equations are derived using the method of moments. The reaction-rate parameter estimates obtained from conversion measurements agree well with estimates obtained via our purely-theoretical quantum chemical calculations.

  5. Motion sickness: a negative reinforcement model.

    Science.gov (United States)

    Bowins, Brad

    2010-01-15

    Theories pertaining to the "why" of motion sickness are in short supply relative to those detailing the "how." Considering the profoundly disturbing and dysfunctional symptoms of motion sickness, it is difficult to conceive of why this condition is so strongly biologically based in humans and most other mammalian and primate species. It is posited that motion sickness evolved as a potent negative reinforcement system designed to terminate motion involving sensory conflict or postural instability. During our evolution and that of many other species, motion of this type would have impaired evolutionary fitness via injury and/or signaling weakness and vulnerability to predators. The symptoms of motion sickness strongly motivate the individual to terminate the offending motion by early avoidance, cessation of movement, or removal of oneself from the source. The motion sickness negative reinforcement mechanism functions much like pain to strongly motivate evolutionary fitness preserving behavior. Alternative why theories focusing on the elimination of neurotoxins and the discouragement of motion programs yielding vestibular conflict suffer from several problems, foremost that neither can account for the rarity of motion sickness in infants and toddlers. The negative reinforcement model proposed here readily accounts for the absence of motion sickness in infants and toddlers, in that providing strong motivation to terminate aberrant motion does not make sense until a child is old enough to act on this motivation.

  6. Diagnosis of bladder tumours in patients with macroscopic haematuria

    DEFF Research Database (Denmark)

    Gandrup, Karen L; Løgager, Vibeke B; Bretlau, Thomas

    2015-01-01

    patients underwent CTU, MRU and flexible cystoscopy. Two uroradiologists individually reviewed the images without any clinical information, using a questionnaire. Patient records and pathology reports were also reviewed. RESULTS: At flexible cystoscopy, MRU and CTU, 32, 19 and 15 bladder lesions were...... identified, respectively. Histopathology showed that 13 of the 29 biopsied lesions were transitional cell carcinomas. Compared with the histopathology, the sensitivity and specificity for detection of tumours by CTU and MRU were 61.5% and 94.9%, and 79.9% and 93.4%, respectively. False-positive detection...... of bladder tumours, compared with histopathology, was reported in seven CTUs and nine MRUs, whereas the number of false-negative findings was five for CTUs and three for MRUs. CONCLUSIONS: Split-bolus CTU or MRU cannot replace cystoscopy in cases of macroscopic haematuria. MRU has a higher sensitivity than...

  7. Polynomial parameterized representation of macroscopic cross section for PWR reactor

    International Nuclear Information System (INIS)

    Fiel, Joao Claudio B.

    2015-01-01

    The purpose of this work is to describe, by means of Tchebychev polynomial, a parameterized representation of the homogenized macroscopic cross section for PWR fuel element as a function of soluble boron concentration, moderator temperature, fuel temperature, moderator density and 235 U 92 enrichment. Analyzed cross sections are: fission, scattering, total, transport, absorption and capture. This parameterization enables a quick and easy determination of the problem-dependent cross-sections to be used in few groups calculations. The methodology presented here will enable to provide cross-sections values to perform PWR core calculations without the need to generate them based on computer code calculations using standard steps. The results obtained by parameterized cross-sections functions, when compared with the cross-section generated by SCALE code calculations, or when compared with K inf , generated by MCNPX code calculations, show a difference of less than 0.7 percent. (author)

  8. Macroscopic quantum electrodynamics of high-Q cavities

    Energy Technology Data Exchange (ETDEWEB)

    Khanbekyan, Mikayel

    2009-10-27

    In this thesis macroscopic quantum electrodynamics in linear media was applied in order to develop an universally valid quantum theory for the description of the interaction of the electromagnetic field with atomic sources in high-Q cavities. In this theory a complete description of the characteristics of the emitted radiation is given. The theory allows to show the limits of the applicability of the usually applied theory. In order to establish an as possible generally valid theory first the atom-field interaction was studied in the framework of macroscopic quantum electrodynamics in dispersive and absorptive media. In order to describe the electromagnetic field from Maxwell's equations was started, whereby the noise-current densities, which are connected with the absorption of the medium, were included. The solution of these equations expresses the electromagnetic field variables by the noise-current densities by means of Green's tensor of the macroscopic Maxwell equations. The explicit quantization is performed by means of the noise-current densities, whereby a diagonal Hamiltonian is introduced, which then guarantees the time development according to Maxwell's equation and the fulfillment of the fundamental simultaneous commutation relations of the field variables. In the case of the interaction of the medium-supported field with atoms the Hamiltonian must be extended by atom-field interactions energies, whereby the canonical coupling schemes of the minimal or multipolar coupling can be used. The dieelectric properties of the material bodies as well as their shape are coded in the Green tensor of the macroscopic Maxwell equations. As preparing step first the Green tensor was specified in order to derive three-dimensional input-output relations for the electromagnetic field operators on a plane multilayer structure. Such a general dewscription of the electromagnetic field allows the inclusion both of dispersion and absorption of the media and the

  9. Macroscopic Modeling of Transport Phenomena in Direct Methanol Fuel Cells

    DEFF Research Database (Denmark)

    Olesen, Anders Christian

    An increasing need for energy efficiency and high energy density has sparked a growing interest in direct methanol fuel cells for portable power applications. This type of fuel cell directly generates electricity from a fuel mixture consisting of methanol and water. Although this technology...... surpasses batteries in important areas, fundamental research is still required to improve durability and performance. Particularly the transport of methanol and water within the cell structure is difficult to study in-situ. A demand therefore exist for the fundamental development of mathematical models...... for studying their transport. In this PhD dissertation the macroscopic transport phenomena governing direct methanol fuel cell operation are analyzed, discussed and modeled using the two-fluid approach in the computational fluid dynamics framework of CFX 14. The overall objective of this work is to extend...

  10. Macroscopic Floquet topological crystalline steel and superconductor pump

    Science.gov (United States)

    Rossi, Anna M. E. B.; Bugase, Jonas; Fischer, Thomas M.

    2017-08-01

    The transport of a macroscopic steel sphere and a superconducting sphere on top of two-dimensional periodic magnetic patterns is studied experimentally and compared with the theory and with experiments on topological transport of magnetic colloids. Transport of the steel and superconducting sphere is achieved by moving an external permanent magnet on a closed loop around the two-dimensional crystal. The transport is topological, i.e., the spheres are transported by a primitive unit vector of the lattice when the external magnet loop winds around specific directions. We experimentally determine the set of directions the loops must enclose for nontrivial transport of the spheres into various directions. We show that the loops can be used to sort steel and superconducting spheres. We show that the topological transport is robust with respect to the scale of the system and therefore speculate on its down scalability to the molecular scale.

  11. Generation of macroscopic singlet states in atomic ensembles

    Science.gov (United States)

    Tóth, Géza; Mitchell, Morgan W.

    2010-05-01

    We study squeezing of the spin uncertainties by quantum non-demolition (QND) measurement in non-polarized spin ensembles. Unlike the case of polarized ensembles, the QND measurements can be performed with negligible back-action, which allows, in principle, perfect spin squeezing as quantified by Tóth et al (2007 Phys. Rev. Lett. 99 250405). The generated spin states approach many-body singlet states and contain a macroscopic number of entangled particles even when individual spin is large. We introduce the Gaussian treatment of unpolarized spin states and use it to estimate the achievable spin squeezing for realistic experimental parameters. Our proposal might have applications for magnetometry with a high spatial resolution or quantum memories storing information in decoherence free subspaces.

  12. Fault detection by surface seismic scanning tunneling macroscope: Field test

    KAUST Repository

    Hanafy, Sherif M.

    2014-08-05

    The seismic scanning tunneling macroscope (SSTM) is proposed for detecting the presence of near-surface impedance anomalies and faults. Results with synthetic data are consistent with theory in that scatterers closer to the surface provide brighter SSTM profiles than those that are deeper. The SSTM profiles show superresolution detection if the scatterers are in the near-field region of the recording line. The field data tests near Gulf of Aqaba, Haql, KSA clearly show the presence of the observable fault scarp, and identify the subsurface presence of the hidden faults indicated in the tomograms. Superresolution detection of the fault is achieved, even when the 35 Hz data are lowpass filtered to the 5-10 Hz band.

  13. Macroscopic chirality of a liquid crystal from nonchiral molecules

    International Nuclear Information System (INIS)

    Jakli, A.; Nair, G. G.; Lee, C. K.; Sun, R.; Chien, L. C.

    2001-01-01

    The transfer of chirality from nonchiral polymer networks to the racemic B2 phase of nonchiral banana-shaped molecules is demonstrated. This corresponds to the transfer of chirality from an achiral material to another achiral material. There are two levels of chirality transfers. (a) On a microscopic level the presence of a polymer network (chiral or nonchiral) favors a chiral state over a thermodynamically stable racemic state due to the inversion symmetry breaking at the polymer-liquid crystal interfaces. (b) A macroscopically chiral (enantimerically enriched) sample can be produced if the polymer network has a helical structure, and/or contains chemically chiral groups. The chirality transfer can be locally suppressed by exposing the liquid crystal to a strong electric field treatment

  14. Fault detection by surface seismic scanning tunneling macroscope: Field test

    KAUST Repository

    Hanafy, Sherif M.; Schuster, Gerard T.

    2014-01-01

    The seismic scanning tunneling macroscope (SSTM) is proposed for detecting the presence of near-surface impedance anomalies and faults. Results with synthetic data are consistent with theory in that scatterers closer to the surface provide brighter SSTM profiles than those that are deeper. The SSTM profiles show superresolution detection if the scatterers are in the near-field region of the recording line. The field data tests near Gulf of Aqaba, Haql, KSA clearly show the presence of the observable fault scarp, and identify the subsurface presence of the hidden faults indicated in the tomograms. Superresolution detection of the fault is achieved, even when the 35 Hz data are lowpass filtered to the 5-10 Hz band.

  15. The N-salicylidene aniline mesogen: Microscopic and macroscopic properties

    International Nuclear Information System (INIS)

    Nesrullazade, A.

    2004-01-01

    The vast majority of compounds exhibiting Iiquid crystalline phases may be regarded as having a rigid molecular central group with one or two flexible terminal alkyl or alkyloxy chains. The N-saIicyIidene anilines are very interesting and important materials both from fundamental and application points of view. These materials are on the one hand the ligands used to obtain metal containing complexes and on the other hand they are materials having the thermotropic mesomorphism. In this work we present investigations of microscopic and macroscopic properties of the 4-(Octyloxy)-N-(4-hexylphenyl)-2-hydrobenzaIimine (8SA) compound which was synthesized by our group. The 8SA compound shows the smectic C and nematic mesophases. These mesophases are enantiotropic and display specific confocal and schlieren textures, respectively. Thermotropic and thermodynamical properties of the straight and reverse phase transitions between smectic C and nematic mesophases and between nematic mesophase and isotropic liquid have been investigated

  16. Non-Poissonian photon statistics from macroscopic photon cutting materials.

    Science.gov (United States)

    de Jong, Mathijs; Meijerink, Andries; Rabouw, Freddy T

    2017-05-24

    In optical materials energy is usually extracted only from the lowest excited state, resulting in fundamental energy-efficiency limits such as the Shockley-Queisser limit for single-junction solar cells. Photon-cutting materials provide a way around such limits by absorbing high-energy photons and 'cutting' them into multiple low-energy excitations that can subsequently be extracted. The occurrence of photon cutting or quantum cutting has been demonstrated in a variety of materials, including semiconductor quantum dots, lanthanides and organic dyes. Here we show that photon cutting results in bunched photon emission on the timescale of the excited-state lifetime, even when observing a macroscopic number of optical centres. Our theoretical derivation matches well with experimental data on NaLaF 4 :Pr 3+ , a material that can cut deep-ultraviolet photons into two visible photons. This signature of photon cutting can be used to identify and characterize new photon-cutting materials unambiguously.

  17. Modeling Macroscopic Shape Distortions during Sintering of Multi-layers

    DEFF Research Database (Denmark)

    Tadesse Molla, Tesfaye

    as to help achieve defect free multi-layer components. The initial thickness ratio between the layers making the multi-layer has also significant effect on the extent of camber evolution depending on the material systems. During sintering of tubular bi-layer structures, tangential (hoop) stresses are very...... large compared to radial stresses. The maximum value of hoop stress, which can generate processing defects such as cracks and coating peel-offs, occurs at the beginning of the sintering cycle. Unlike most of the models defining material properties based on porosity and grain size only, the multi...... (firing). However, unintended features like shape instabilities of samples, cracks or delamination of layers may arise during sintering of multi-layer composites. Among these defects, macroscopic shape distortions in the samples can cause problems in the assembly or performance of the final component...

  18. Sensing Movement: Microsensors for Body Motion Measurement

    Directory of Open Access Journals (Sweden)

    Hansong Zeng

    2011-01-01

    Full Text Available Recognition of body posture and motion is an important physiological function that can keep the body in balance. Man-made motion sensors have also been widely applied for a broad array of biomedical applications including diagnosis of balance disorders and evaluation of energy expenditure. This paper reviews the state-of-the-art sensing components utilized for body motion measurement. The anatomy and working principles of a natural body motion sensor, the human vestibular system, are first described. Various man-made inertial sensors are then elaborated based on their distinctive sensing mechanisms. In particular, both the conventional solid-state motion sensors and the emerging non solid-state motion sensors are depicted. With their lower cost and increased intelligence, man-made motion sensors are expected to play an increasingly important role in biomedical systems for basic research as well as clinical diagnostics.

  19. Averaging problem in general relativity, macroscopic gravity and using Einstein's equations in cosmology.

    Science.gov (United States)

    Zalaletdinov, R. M.

    1998-04-01

    The averaging problem in general relativity is briefly discussed. A new setting of the problem as that of macroscopic description of gravitation is proposed. A covariant space-time averaging procedure is described. The structure of the geometry of macroscopic space-time, which follows from averaging Cartan's structure equations, is described and the correlation tensors present in the theory are discussed. The macroscopic field equations (averaged Einstein's equations) derived in the framework of the approach are presented and their structure is analysed. The correspondence principle for macroscopic gravity is formulated and a definition of the stress-energy tensor for the macroscopic gravitational field is proposed. It is shown that the physical meaning of using Einstein's equations with a hydrodynamic stress-energy tensor in looking for cosmological models means neglecting all gravitational field correlations. The system of macroscopic gravity equations to be solved when the correlations are taken into consideration is given and described.

  20. Method and apparatus to control the lateral motion of a long metal bar being formed by a mechanical process such as rolling or drawing

    Science.gov (United States)

    Chang, Tzyy-Shuh [Ann Arbor, MI; Huang, Hsun-Hau [Ann Arbor, MI; Lin, Chang-Hung [Ypsilanti, MI

    2011-01-04

    An apparatus to control lateral motion of a bar moving along a guidance path includes a pair of rotatable hubs each having at least first and second rollers at locations around the perimeter of the hub. The first roller has a first retaining groove of a first radius and the second roller has a second groove of a second radius smaller than the first radius. Each hub further includes at least one guiding element located between the rollers with a guide channel extending in the outer surface. A mounting system allows the hubs to be rotated between first and second positions. In the first position the first rollers oppose each other forming a guideway having a first, enlarged diameter for capturing a free end of an approaching bar. In the second position the second rollers form a second, smaller diameter to match the actual size of the bar.

  1. Robot motion control in mobile environment

    Institute of Scientific and Technical Information of China (English)

    Iliya V Miroshnik; HUANG Xian-lin(黄显林); HE Jie(贺杰)

    2003-01-01

    With the problem of robot motion control in dynamic environment represented by mobile obstacles,working pieces and external mechanisms considered, a relevant control actions design procedure has been pro-posed to provide coordination of robot motions with respect to the moving external objects so that an extension ofrobot spatial motion techniques and active robotic strategies based on approaches of nonlinear control theory canbe achieved.

  2. Stochastic mechanics and quantum theory

    International Nuclear Information System (INIS)

    Goldstein, S.

    1987-01-01

    Stochastic mechanics may be regarded as both generalizing classical mechanics to processes with intrinsic randomness, as well as providing the sort of detailed description of microscopic events declared impossible under the traditional interpretation of quantum mechanics. It avoids the many conceptual difficulties which arise from the assumption that quantum mechanics, i.e., the wave function, provides a complete description of (microscopic) physical reality. Stochastic mechanics presents a unified treatment of the microscopic and macroscopic domains, in which the process of measurement plays no special physical role and which reduces to Newtonian mechanics in the macroscopic limit

  3. Mechanics

    CERN Document Server

    Hartog, J P Den

    1961-01-01

    First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

  4. [Cartilage tissue reconstruction by the polymer biomaterials--early macroscopic and histological results].

    Science.gov (United States)

    Scierski, Wojciech; Polok, Aleksandra; Namysłowski, Grzegorz; Nozyński, Jerzy; Turecka, Lucyna; Urbaniec, Natalia; Pamuła, Elzbieta

    2009-09-01

    The surgical treatment of large cartilage defects in the region of head and neck is often impossible because of the atrophy of surrounding tissues and lack of suitable material for reconstruction. In the surgical treatment many of methods and reconstructive materials have been used. For many years the suitable synthetic material for the cartilage defects reconstruction has been searched for. Was to evaluate two different biomaterials with proper mechanical and biological features for the cartilage replacement. Two type of biomaterials in this study were used: resorbable polymer - poly(L-lactide-co-glycolide) (PLG) acting as a supportive matrix. A thin layer of sodium hyaluronate (Hyal) was also deposited on the surface as well in the pore walls of PLG scaffolds in order to provide biologically active molecules promoting differentiation and regeneration of the tissue. The studies were performed on the 50 animals--rabbits divided into 2 groups. The animals were operated in the general anaesthesia. The incision was done along the edge of the rabbit's auricle. Perichondrium and cartilage of the auricle on the surface 4 x 3 cm were prepared. Subperichondrically 1 x 1 cm fragment of the cartilage was removed by the scissors. This fragment was then replaced by the biomaterials: PLG in first group of 25 rabbits and PLG-Hyal in second group 25 rabbits. The tissues were sutured with polyglycolide Safil 3-0. The animals obtained Enrofloxacin for three days after the operation. Then 1, 4 and 12 weeks after the surgery the animals were painlessly euthanized by an overdose of Morbital. Implants and surrounding tissues were excised and observed macroscopically and using an optical microscope. In all the observation periods we observed proper macroscopic healing process of biomaterials. We didn't stated strong inflammatory process and necrosis around the implanted biomaterials. The histological and macroscopic examinations indicated that both materials developed in this study have

  5. Spatial filtering precedes motion detection.

    Science.gov (United States)

    Morgan, M J

    1992-01-23

    When we perceive motion on a television or cinema screen, there must be some process that allows us to track moving objects over time: if not, the result would be a conflicting mass of motion signals in all directions. A possible mechanism, suggested by studies of motion displacement in spatially random patterns, is that low-level motion detectors have a limited spatial range, which ensures that they tend to be stimulated over time by the same object. This model predicts that the direction of displacement of random patterns cannot be detected reliably above a critical absolute displacement value (Dmax) that is independent of the size or density of elements in the display. It has been inferred that Dmax is a measure of the size of motion detectors in the visual pathway. Other studies, however, have shown that Dmax increases with element size, in which case the most likely interpretation is that Dmax depends on the probability of false matches between pattern elements following a displacement. These conflicting accounts are reconciled here by showing that Dmax is indeed determined by the spacing between the elements in the pattern, but only after fine detail has been removed by a physiological prefiltering stage: the filter required to explain the data has a similar size to the receptive field of neurons in the primate magnocellular pathway. The model explains why Dmax can be increased by removing high spatial frequencies from random patterns, and simplifies our view of early motion detection.

  6. Rotational damping motion in nuclei

    International Nuclear Information System (INIS)

    Egido, J.L.; Faessler, A.

    1991-01-01

    The recently proposed model to explain the mechanism of the rotational motion damping in nuclei is exactly solved. When compared with the earlier approximative solution, we find significative differences in the low excitation energy limit (i.e. Γ μ 0 ). For the strength functions we find distributions going from the Wigner semicircle through gaussians to Breit-Wigner shapes. (orig.)

  7. Motion in radiotherapy

    DEFF Research Database (Denmark)

    Korreman, Stine Sofia

    2012-01-01

    This review considers the management of motion in photon radiation therapy. An overview is given of magnitudes and variability of motion of various structures and organs, and how the motion affects images by producing artifacts and blurring. Imaging of motion is described, including 4DCT and 4DPE...

  8. Modelling the fragmentation mechanisms

    International Nuclear Information System (INIS)

    Bougault, R.; Durand, D.; Gulminelli, F.

    1998-01-01

    We have investigated the role of high amplitude collective motion in the nuclear fragmentation by using semi-classical macroscopic, as well as, microscopic simulations (BUU). These studies are motivated by the search of instabilities responsible for nuclear fragmentation. Two cases were examined: the bubble formation following the collective expansion of the compressed nucleus in case of very central reactions and, in the case of the semi-central collisions, the fast fission of the two partners issued from a binary reaction, in their corresponding Coulomb field. In the two cases the fragmentation channel is dominated by the inter-relation between the Coulomb and nuclear fields, and it is possible to obtain semi-quantitative predictions as functions of interaction parameters. The transport equations of BUU type predicts for central reactions formation of a high density transient state. Of much interest is the mechanism subsequent to de-excitation. It seems reasonable to conceive that the pressure stocked in the compressional mode manifests itself as a collective expansion of the system. As the pressure is a increasing function of the available energy one can conceive a variety of energy depending exit channels, starting from the fragmentation due the amplification of fluctuations interior to the spinodal zone up to the complete vaporization of the highly excited system. If the reached pressure is sufficiently high the reaction final state may preserve the memory of the entrance channel as a collective radial energy superimposed to the thermal disordered motion. Distributions of particles in the configuration space for both central and semi-central reactions for the Pb+Au system are presented. The rupture time is estimated to the order of 300 fm/c, and is strongly dependent on the initial temperature. The study of dependence of the rupture time on the interaction parameters is under way

  9. Hyperdynamic CSF motion profiles found in idiopathic normal pressure hydrocephalus and Alzheimer's disease assessed by fluid mechanics derived from magnetic resonance images.

    Science.gov (United States)

    Takizawa, Ken; Matsumae, Mitsunori; Hayashi, Naokazu; Hirayama, Akihiro; Yatsushiro, Satoshi; Kuroda, Kagayaki

    2017-10-18

    Magnetic resonance imaging (MRI) does not only ascertain morphological features, but also measures physiological properties such as fluid velocity or pressure gradient. The purpose of this study was to investigate cerebrospinal fluid (CSF) dynamics in patients with morphological abnormalities such as enlarged brain ventricles and subarachnoid spaces. We used a time-resolved three dimensional phase contrast (3D-PC) MRI technique to quantitatively evaluate CSF dynamics in the Sylvian aqueduct of healthy elderly individuals and patients with either idiopathic normal pressure hydrocephalus (iNPH) or Alzheimer's disease (AD) presenting with ventricular enlargement. Nineteen healthy elderly individuals, ten iNPH patients, and seven AD patients (all subjects ≥ 60 years old) were retrospectively evaluated 3D-PC MRI. The CSF velocity, pressure gradient, and rotation in the Sylvian aqueduct were quantified and compared between the three groups using Kolmogorov-Smirnov and Mann-Whitney U tests. There was no statistically significant difference in velocity among the three groups. The pressure gradient was not significantly different between the iNPH and AD groups, but was significantly different between the iNPH group and the healthy controls (p < 0.001), and similarly, between the AD group and the healthy controls (p < 0.001). Rotation was not significantly different between the iNPH and AD groups, but was significantly different between the iNPH group and healthy controls (p < 0.001), and similarly, between the AD group and the healthy controls (p < 0.001). Quantitative analysis of CSF dynamics with time resolved 3D-PC MRI revealed differences and similarities in the Sylvian aqueduct between healthy elderly individuals, iNPH patients, and AD patients. The results showed that CSF motion is in a hyperdynamic state in both iNPH and AD patient groups compared to healthy elderly individuals, and that iNPH patients and AD patients display similar CSF motion profiles.

  10. Unmasking the mechanism of diffuse left ventricular wall motion abnormality in ischemic cardiomyopathy by resting-redistribution thallium-201 single photon computed tomography

    International Nuclear Information System (INIS)

    Namura, Hiroyuki; Yamabe, Hiroshi; Kakimoto, Tetsuya; Hashimoto, Yasunori; Yasaka, Yoshinori; Yoshida, Hiroaki; Itoh, Kazushi; Yokoyama, Mitsuhiro; Maeda, Kazumi.

    1992-01-01

    The study population comprised patients with ischemic cardiomyopathy (ICM) who had left ventricular wall motion (LVWM) abnormality in 5 or more segments (n=9), those with extensive myocardial infarction (EMI) having LVWM abnormality in 4 or less segments (n=12), and those with dilated left ventricle (DLV) having LVWM abnormality in all 7 segments (n=9). Defect scores (DS), obtained by initial and delayed Tl-201 myocardial single photon emission computed tomography at rest, were visually assessed to compare perfusion patterns in the three patient groups. The group of ICM patients had greater defect segments (DSeg) and % redistribution (Rd) index than the other two groups, although there was no difference in the number of angiographically proven infarct-related coronary vessels between EMI and ICM. In the group of ICM patients, there was inverse correlation not only between left ventricular ejection fraction and the sum of DS but also between left ventricular enddiastolic volume index and both the sum of DSeg and % Rd index. The group of DLV patients had small sum of DSeg and redistribution, compared with the other two groups. Although diffuse LVWM abnormality, as observed in the group of ICM patients, was considered attributable to potential decrease of coronary perfusion shown as defect on SPECT images, it did not always coincide with findings of coronary angiography. Both DSeg and redistribution phenomenon on SPECT images seemed to have the ability to evaluate the severity of ICM, as well as to differentiate ICM, EMI, and DLV. (N.K.)

  11. Adaptive motion of animals and machines

    National Research Council Canada - National Science Library

    Kimura, Hiroshi

    2006-01-01

    ... single function in a control system and mechanism. That is, adaptation in motion is induced at every level from the central nervous system to the musculoskeletal system. Thus, we organized the International Symposium on Adaptive Motion in Animals and Machines (AMAM) for scientists and engineers concerned with adaptation on various levels to be broug...

  12. Effect of electrical and mechanical poling history on domain orientation and piezoelectric properties of soft and hard PZT ceramics

    International Nuclear Information System (INIS)

    Marsilius, Mie; Granzow, Torsten; Jones, Jacob L

    2011-01-01

    The superior piezoelectric properties of all polycrystalline ferroelectrics are based on the extent of non-180 0 domain wall motion under electrical and mechanical poling loads. To distinguish between 180 0 and non-180 0 domain wall motion in a soft-doped and a hard-doped lead zirconate titanate (PZT) ceramic, domain texture measurements were performed using x-ray and neutron diffraction after different loading procedures. Comparing the results to measurements of the remanent strain and piezoelectric coefficient allowed the differentiation between different microstructural contributions to the macroscopic parameters. Both types of ceramic showed similar behavior under electric field, but the hard-doped material was more susceptible to mechanical load. A considerable fraction of the piezoelectric coefficient originated from poling by the preferred orientation of 180 0 domains.

  13. Effect of electrical and mechanical poling history on domain orientation and piezoelectric properties of soft and hard PZT ceramics

    Science.gov (United States)

    Marsilius, Mie; Granzow, Torsten; Jones, Jacob L.

    2011-02-01

    The superior piezoelectric properties of all polycrystalline ferroelectrics are based on the extent of non-180° domain wall motion under electrical and mechanical poling loads. To distinguish between 180° and non-180° domain wall motion in a soft-doped and a hard-doped lead zirconate titanate (PZT) ceramic, domain texture measurements were performed using x-ray and neutron diffraction after different loading procedures. Comparing the results to measurements of the remanent strain and piezoelectric coefficient allowed the differentiation between different microstructural contributions to the macroscopic parameters. Both types of ceramic showed similar behavior under electric field, but the hard-doped material was more susceptible to mechanical load. A considerable fraction of the piezoelectric coefficient originated from poling by the preferred orientation of 180° domains.

  14. Feedback Gating Control for Network Based on Macroscopic Fundamental Diagram

    Directory of Open Access Journals (Sweden)

    YangBeibei Ji

    2016-01-01

    Full Text Available Empirical data from Yokohama, Japan, showed that a macroscopic fundamental diagram (MFD of urban traffic provides for different network regions a unimodal low-scatter relationship between network vehicle density and network space-mean flow. This provides new tools for network congestion control. Based on MFD, this paper proposed a feedback gating control policy which can be used to mitigate network congestion by adjusting signal timings of gating intersections. The objective of the feedback gating control model is to maximize the outflow and distribute the allowed inflows properly according to external demand and capacity of each gating intersection. An example network is used to test the performance of proposed feedback gating control model. Two types of background signalization types for the intersections within the test network, fixed-time and actuated control, are considered. The results of extensive simulation validate that the proposed feedback gating control model can get a Pareto improvement since the performance of both gating intersections and the whole network can be improved significantly especially under heavy demand situations. The inflows and outflows can be improved to a higher level, and the delay and queue length at all gating intersections are decreased dramatically.

  15. Communication: On the diffusion tensor in macroscopic theory of cavitation

    Science.gov (United States)

    Shneidman, Vitaly A.

    2017-08-01

    The classical description of nucleation of cavities in a stretched fluid relies on a one-dimensional Fokker-Planck equation (FPE) in the space of their sizes r, with the diffusion coefficient D(r) constructed for all r from macroscopic hydrodynamics and thermodynamics, as shown by Zeldovich. When additional variables (e.g., vapor pressure) are required to describe the state of a bubble, a similar approach to construct a diffusion tensor D ^ generally works only in the direct vicinity of the thermodynamic saddle point corresponding to the critical nucleus. It is shown, nevertheless, that "proper" kinetic variables to describe a cavity can be selected, allowing to introduce D ^ in the entire domain of parameters. In this way, for the first time, complete FPE's are constructed for viscous volatile and inertial fluids. In the former case, the FPE with symmetric D ^ is solved numerically. Alternatively, in the case of an inertial fluid, an equivalent Langevin equation is considered; results are compared with analytics. The suggested approach is quite general and can be applied beyond the cavitation problem.

  16. Macroscopic multigroup constants for accelerator driven system core calculation

    International Nuclear Information System (INIS)

    Heimlich, Adino; Santos, Rubens Souza dos

    2011-01-01

    The high-level wastes stored in facilities above ground or shallow repositories, in close connection with its nuclear power plant, can take almost 106 years before the radiotoxicity became of the order of the background. While the disposal issue is not urgent from a technical viewpoint, it is recognized that extended storage in the facilities is not acceptable since these ones cannot provide sufficient isolation in the long term and neither is it ethical to leave the waste problem to future generations. A technique to diminish this time is to transmute these long-lived elements into short-lived elements. The approach is to use an Accelerator Driven System (ADS), a sub-critical arrangement which uses a Spallation Neutron Source (SNS), after separation the minor actinides and the long-lived fission products (LLFP), to convert them to short-lived isotopes. As an advanced reactor fuel, still today, there is a few data around these type of core systems. In this paper we generate macroscopic multigroup constants for use in calculations of a typical ADS fuel, take into consideration, the ENDF/BVI data file. Four energy groups are chosen to collapse the data from ENDF/B-VI data file by PREPRO code. A typical MOX fuel cell is used to validate the methodology. The results are used to calculate one typical subcritical ADS core. (author)

  17. The universe as an ultimate macroscopic quantum phenomenon?

    International Nuclear Information System (INIS)

    Hu, Bei-Lok

    2005-01-01

    Full text: We explore two unconventional proposals on the meaning of quantum gravity and the quantum properties of spacetime. The first is an older proposal of mine that general relativity is the hydrodynamic limit of some fundamental theories of the microscopic structure of spacetime and matter, a more specific derivative of the idea of Sakharov. The latter is a more recent thought of mine on the possibility that spacetime is a condensate (Bose or Fermi). These proposals have implications radically different from the conventional views. For the former, spacetime described by a differentiable manifold is regarded as an emergent entity and the metric or connection forms are collective variables valid only at the low energy, long wavelength limit of the micro-theories of spacetime and matter. This view would render irrelevant the traditional efforts to find ways to quantize general relativity, because it would only give us the equivalent of phonon physics, not a theory of electrons or photons, QED. In the second proposal, even without the knowledge of what the 'atom of spacetime' is, the mere thought that spacetime at all energies below the Planck scale, including today's, is quantum rather than classical, has many challenging consequences. We discuss the implications of this view pertaining to issues in gravitation and cosmology, as well as to macroscopic quantum coherence phenomena. (author)

  18. Macroscopic local-field effects on photoabsorption processes

    International Nuclear Information System (INIS)

    Ma Xiaoguang; Gong Yubing; Wang Meishan; Wang Dehua

    2008-01-01

    The influence of the local-field effect on the photoabsorption cross sections of the atoms which are embedded in the macroscopic medium has been studied by a set of alternative expressions in detail. Some notes on the validity of some different local-field models used to study the photoabsorption cross sections of atoms in condensed matter have been given for the first time. Our results indicate that the local fields can have substantial and different influence on the photoabsorption cross section of atoms in condensed matter for different models. Clausius-Mossotti model and Onsager model have proved to be more reasonable to describe the local field in gas, liquid, or even some simple solid, while Glauber-Lewenstein model probably is wrong in these conditions except for the ideal gas. A procedure which can avoid the errors introduced by Kramers-Kronig transformation has been implemented in this work. This procedure can guarantee that the theoretical studies on the local field effects will not be influenced by the integral instability of the Kramers-Kronig transformation

  19. Theory and feasibility tests for a seismic scanning tunnelling macroscope

    KAUST Repository

    Schuster, Gerard T.

    2012-09-01

    We propose a seismic scanning tunnelling macroscope (SSTM) that can detect subwavelength scatterers in the near-field of either the source or the receivers. Analytic formulas for the time reverse mirror (TRM) profile associated with a single scatterer model show that the spatial resolution limit to be, unlike the Abbe limit of λ/2, independent of wavelength and linearly proportional to the source-scatterer separation as long as the scatterer is in the near-field region. This means that, as the scatterer approaches the source, imaging of the scatterer with super-resolution can be achieved. Acoustic and elastic simulations support this concept, and a seismic experiment in an Arizona tunnel shows a TRM profile with super-resolution adjacent to the fault location. The SSTM is analogous to the optical scanning tunnelling microscopes having subwavelength resolution. Scaled to seismic frequencies, it is theoretically possible to extract 100 Hz information from 20 Hz data by the imaging of near-field seismic energy.

  20. Validity of macroscopic concepts for fluids on a microscopic scale

    International Nuclear Information System (INIS)

    Alder, B.J.; Alley, W.E.; Pollock, E.L.

    1981-01-01

    By Fourier decomposition of the appropriate fluctuation it is possible within the regime of linear response to extend the concept of both thermodynamic quantities and transport coefficients to their dependence on both wavelength and frequency. Experimentally these generalized macroscopic properties are accessible through neutron diffraction and, as examples, the dependence of the sound speed on wavelength and the diffusion coefficient on time are discussed. Through the molecular dynamics computer method the dependence of the viscosity on wavelength is calculated and applied with spectacular success to predict the dependence of the friction coefficient on the size of a Brownian particle all the way to atomic dimensions. On the other hand, the dielectric constant continuum concept, as applied to a charge or dipole in a cavity, generally fails to predict even the correct field at large distance from the charge. Avoiding the introduction of a cavity cures that problem, but the generalized dielectric constant fails badly in predicting the field at shorter distances from the charge. (orig.)

  1. Motion Transplantation Techniques: A Survey

    NARCIS (Netherlands)

    van Basten, Ben; Egges, Arjan

    2012-01-01

    During the past decade, researchers have developed several techniques for transplanting motions. These techniques transplant a partial auxiliary motion, possibly defined for a small set of degrees of freedom, on a base motion. Motion transplantation improves motion databases' expressiveness and

  2. Figure-ground segregation modulates apparent motion.

    Science.gov (United States)

    Ramachandran, V S; Anstis, S

    1986-01-01

    We explored the relationship between figure-ground segmentation and apparent motion. Results suggest that: static elements in the surround can eliminate apparent motion of a cluster of dots in the centre, but only if the cluster and surround have similar "grain" or texture; outlines that define occluding surfaces are taken into account by the motion mechanism; the brain uses a hierarchy of precedence rules in attributing motion to different segments of the visual scene. Being designated as "figure" confers a high rank in this scheme of priorities.

  3. Grasping the Second Law of Thermodynamics at University: The Consistency of Macroscopic and Microscopic Explanations

    Science.gov (United States)

    Leinonen, Risto; Asikainen, Mervi A.; Hirvonen, Pekka E.

    2015-01-01

    This study concentrates on evaluating the consistency of upper-division students' use of the second law of thermodynamics at macroscopic and microscopic levels. Data were collected by means of a paper and pencil test (N = 48) focusing on the macroscopic and microscopic features of the second law concerned with heat transfer processes. The data…

  4. Tracer sorption and macroscopic transport in clay nano-pores: a lattice-Boltzmann study

    International Nuclear Information System (INIS)

    Levesque, Maximilien; Rotenberg, Benjamin; Duvail, Magali; Benichou, Olivier; Voituriez, Raphael; Pagonabarraga, Ignacio; Frenkel, Daan

    2012-01-01

    Document available in extended abstract form only. The Agence Nationale pour la gestion des Dechets Radioactifs (ANDRA) has been entrusted to find a safe solution for disposing of existing and future nuclear wastes. A prototype site has been considered for the waste disposal in a deep underground sedimentary geological formation. It is composed of clay minerals chosen, among other reasons, for their remarkable ability to limit radionuclide transport. Clay minerals are complex charged porous media characterized by heterogeneities at several length scales. They naturally occur as an assembly of few nano-meter-sized particles connected to form 10 to 100 nm interparticle pores containing water and ions. This intrinsically multi-scale structure, that gives the material its remarkable properties, makes the description of sorption and transport phenomena of transported ions particularly challenging. Experimental studies of water and ion transport through clays mostly consist in evaluating macroscopic effective transport coefficients like permeability or conductivity. They showed that the main transport mechanism is an effective diffusion that not only depends on particle charge but also on its chemical nature, or specificity. The goal of assessing the performance of clays as confinement barriers, particularly in the context of the geological disposal of nuclear waste, requires not only quantitative prediction of the retention and transport of species but also an understanding of the microscopic mechanisms underlying them. A successful approach has been to use numerical simulations via the Lattice-Boltzmann method (LB). It consists in making evolve populations describing the fluid at a level which is consistent with time and length-scales involved in transport properties, while still including a microscopic description of the phenomena. The transport of charged ions at the pore scale has recently been included in LB. In this method, the evolution of a tracer population is

  5. The alignment of carbon nanotubes: an effective route to extend their excellent properties to macroscopic scale.

    Science.gov (United States)

    Sun, Xuemei; Chen, Tao; Yang, Zhibin; Peng, Huisheng

    2013-02-19

    To improve the practical application of carbon nanotubes, it is critically important to extend their physical properties from the nanoscale to the macroscopic scale. Recently, chemists aligned continuous multiwalled carbon nanotube (MWCNT) sheets and fibers to produce materials with high mechanical strength and electrical conductivity. This provided an important clue to the use of MWCNTs at macroscopic scale. Researchers have made multiple efforts to optimize this aligned structure and improve the properties of MWCNT sheets and fibers. In this Account, we briefly highlight the new synthetic methods and promising applications of aligned MWCNTs for organic optoelectronic materials and devices. We describe several general methods to prepare both horizontally and perpendicularly aligned MWCNT/polymer composite films, through an easy solution or melting process. The composite films exhibit the combined properties of being flexible, transparent, and electrically conductive. These advances may pave the way to new flexible substrates for organic solar cells, sensing devices, and other related applications. Similarly, we discuss the synthesis of aligned MWCNT/polymer composite fibers with interesting mechanical and electrical properties. Through these methods, we can incorporate a wide variety of soluble or fusible polymers for such composite films and fibers. In addition, we can later introduce functional polymers with conjugated backbones or side chains to improve the properties of these composite materials. In particular, cooperative interactions between aligned MWCNTs and polymers can produce novel properties that do not occur individually. Common examples of this are two types of responsive polymers, photodeformable azobenzene-containing liquid crystalline polymer and chromatic polydiacetylene. Aligning the structure of MWCNTs induces the orientation of azobenzene-containing mesogens, and produces photodeformable polymer elastomers. This strategy also solves the long

  6. Macroscopic behavior and microscopic magnetic properties of nanocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Lähderanta, E., E-mail: Erkki.Lahderanta@lut.fi [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Ryzhov, V.A. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Petersburg Nuclear Physics Institute, NRC “Kurchatov Institute”, Orlova Coppice, Gatchina, Leningrad province 188300 (Russian Federation); Lashkul, A.V. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Galimov, D.M. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); South Ural State University, 454080 Chelyabinsk (Russian Federation); Titkov, A.N. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); A. F. Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation); Matveev, V.V. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Saint-Petersburg State University, Saint-Petersburg 198504 (Russian Federation); Mokeev, M.V. [Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg (Russian Federation); Kurbakov, A.I. [Petersburg Nuclear Physics Institute, NRC “Kurchatov Institute”, Orlova Coppice, Gatchina, Leningrad province 188300 (Russian Federation); Lisunov, K.G. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Institute of Applied Physics ASM, Academiei Str., 5, MD 2028 Kishinev (Moldova, Republic of)

    2015-06-01

    Here are presented investigations of powder and glass-like samples containing carbon nanoparticles, not intentionally doped and doped with Ag, Au and Co. The neutron diffraction study reveals an amorphous structure of the samples doped with Au and Co, as well as the magnetic scattering due to a long-range FM order in the Co-doped sample. The composition and molecular structure of the sample doped with Au is clarified with the NMR investigations. The temperature dependence of the magnetization, M (T), exhibits large irreversibility in low fields of B=1–7 mT. M (B) saturates already above 2 T at high temperatures, but deviates from the saturation behavior below ~50 (150 K). Magnetic hysteresis is observed already at 300 K and exhibits a power-law temperature decay of the coercive field, B{sub c} (T). The macroscopic behavior above is typical of an assembly of partially blocked magnetic nanoparticles. The values of the saturation magnetization, M{sub s}, and the blocking temperature, T{sub b}, are obtained as well. However, the hysteresis loop in the Co-doped sample differs from that in other samples, and the values of B{sub c} and M{sub s} are noticeably increased. - Highlights: • We have investigated powder and glassy samples with carbon nanoparticles. • They include an undoped sample and those doped with Ag, Au and Co. • Neutron diffraction study reveals amorphous structure of Au- and Co-doped samples. • Composition and molecular structure of Au-doped sample was investigated with NMR. • Magnetic behavior is typical of an assembly of partially blocked magnetic nanoparticles.

  7. Macroscopic behavior and microscopic magnetic properties of nanocarbon

    International Nuclear Information System (INIS)

    Lähderanta, E.; Ryzhov, V.A.; Lashkul, A.V.; Galimov, D.M.; Titkov, A.N.; Matveev, V.V.; Mokeev, M.V.; Kurbakov, A.I.; Lisunov, K.G.

    2015-01-01

    Here are presented investigations of powder and glass-like samples containing carbon nanoparticles, not intentionally doped and doped with Ag, Au and Co. The neutron diffraction study reveals an amorphous structure of the samples doped with Au and Co, as well as the magnetic scattering due to a long-range FM order in the Co-doped sample. The composition and molecular structure of the sample doped with Au is clarified with the NMR investigations. The temperature dependence of the magnetization, M (T), exhibits large irreversibility in low fields of B=1–7 mT. M (B) saturates already above 2 T at high temperatures, but deviates from the saturation behavior below ~50 (150 K). Magnetic hysteresis is observed already at 300 K and exhibits a power-law temperature decay of the coercive field, B c (T). The macroscopic behavior above is typical of an assembly of partially blocked magnetic nanoparticles. The values of the saturation magnetization, M s , and the blocking temperature, T b , are obtained as well. However, the hysteresis loop in the Co-doped sample differs from that in other samples, and the values of B c and M s are noticeably increased. - Highlights: • We have investigated powder and glassy samples with carbon nanoparticles. • They include an undoped sample and those doped with Ag, Au and Co. • Neutron diffraction study reveals amorphous structure of Au- and Co-doped samples. • Composition and molecular structure of Au-doped sample was investigated with NMR. • Magnetic behavior is typical of an assembly of partially blocked magnetic nanoparticles

  8. Innovations in macroscopic evaluation of pancreatic specimens and radiologic correlation

    Directory of Open Access Journals (Sweden)

    Charikleia Triantopoulou

    2016-01-01

    Full Text Available The purpose of this study was to evaluate the feasibility of a novel dissection technique of surgical specimens in different cases of pancreatic tumors and provide a radiologic pathologic correlation. In our hospital, that is a referral center for pancreatic diseases, the macroscopic evaluation of the pancreatectomy specimens is performed by the pathologists using the axial slicing technique (instead of the traditional procedure with longitudinal opening of the main pancreatic and/or common bile duct and slicing along the plane defined by both ducts. The specimen is sliced in an axial plane that is perpendicular to the longitudinal axis of the descending duodenum. The procedure results in a large number of thin slices (3–4 mm. This plane is identical to that of CT or MRI and correlation between pathology and imaging is straightforward. We studied 70 cases of suspected different solid and cystic pancreatic tumors and we correlated the tumor size and location, the structure—consistency (areas of necrosis—hemorrhage—fibrosis—inflammation, the degree of vessels’ infiltration, the size of pancreatic and common bile duct and the distance from resection margins. Missed findings by imaging or pitfalls were recorded and we tried to explain all discrepancies between radiology evaluation and the histopathological findings. Radiologic-pathologic correlation is extremely important, adding crucial information on imaging limitations and enabling quality assessment of surgical specimens. The deep knowledge of different pancreatic tumors’ consistency and way of extension helps to improve radiologists’ diagnostic accuracy and minimize the radiological-surgical mismatching, preventing patients from unnecessary surgery.

  9. Nuclear magnetic resonance studies of macroscopic morphology and dynamics

    International Nuclear Information System (INIS)

    Barrall, G.A.; Lawrence Berkeley Lab., CA

    1995-09-01

    Nuclear magnetic resonance techniques are traditionally used to study molecular level structure and dynamics with a noted exception in medically applied NMR imaging (MRI). In this work, new experimental methods and theory are presented relevant to the study of macroscopic morphology and dynamics using NMR field gradient techniques and solid state two-dimensional exchange NMR. The goal in this work is not to take some particular system and study it in great detail, rather it is to show the utility of a number of new and novel techniques using ideal systems primarily as a proof of principle. By taking advantage of the analogy between NMR imaging and diffraction, one may simplify the experiments necessary for characterizing the statistical properties of the sample morphology. For a sample composed of many small features, e.g. a porous medium, the NMR diffraction techniques take advantage of both the narrow spatial range and spatial isotropy of the sample's density autocorrelation function to obtain high resolution structural information in considerably less time than that required by conventional NMR imaging approaches. The time savings of the technique indicates that NMR diffraction is capable of finer spatial resolution than conventional NMR imaging techniques. Radio frequency NMR imaging with a coaxial resonator represents the first use of cylindrically symmetric field gradients in imaging. The apparatus as built has achieved resolution at the micron level for water samples, and has the potential to be very useful in the imaging of circularly symmetric systems. The study of displacement probability densities in flow through a random porous medium has revealed the presence of features related to the interconnectedness of the void volumes. The pulsed gradient techniques used have proven successful at measuring flow properties for time and length scales considerably shorter than those studied by more conventional techniques

  10. Learning Motion Features for Example-Based Finger Motion Estimation for Virtual Characters

    Science.gov (United States)

    Mousas, Christos; Anagnostopoulos, Christos-Nikolaos

    2017-09-01

    This paper presents a methodology for estimating the motion of a character's fingers based on the use of motion features provided by a virtual character's hand. In the presented methodology, firstly, the motion data is segmented into discrete phases. Then, a number of motion features are computed for each motion segment of a character's hand. The motion features are pre-processed using restricted Boltzmann machines, and by using the different variations of semantically similar finger gestures in a support vector machine learning mechanism, the optimal weights for each feature assigned to a metric are computed. The advantages of the presented methodology in comparison to previous solutions are the following: First, we automate the computation of optimal weights that are assigned to each motion feature counted in our metric. Second, the presented methodology achieves an increase (about 17%) in correctly estimated finger gestures in comparison to a previous method.

  11. Single and two-mode mechanical squeezing of an optically levitated nanodiamond via dressed-state coherence

    International Nuclear Information System (INIS)

    Ge, Wenchao; Bhattacharya, M

    2016-01-01

    Nonclassical states of macroscopic objects are promising for ultrasensitive metrology as well as testing quantum mechanics. In this work, we investigate dissipative mechanical quantum state engineering in an optically levitated nanodiamond. First, we study single-mode mechanical squeezed states by magnetically coupling the mechanical motion to a dressed three-level system provided by a nitrogen-vacancy center in the nanoparticle. Quantum coherence between the dressed levels is created via microwave fields to induce a two-phonon transition, which results in mechanical squeezing. Remarkably, we find that in ultrahigh vacuum quantum squeezing is achievable at room temperature with feedback cooling. For moderate vacuum, quantum squeezing is possible with cryogenic temperature. Second, we present a setup for two mechanical modes coupled to the dressed three levels, which results in two-mode squeezing analogous to the mechanism of the single-mode case. In contrast to previous works, our study provides a deterministic method for engineering macroscopic squeezed states without the requirement for a cavity. (paper)

  12. Single and two-mode mechanical squeezing of an optically levitated nanodiamond via dressed-state coherence

    Science.gov (United States)

    Ge, Wenchao; Bhattacharya, M.

    2016-10-01

    Nonclassical states of macroscopic objects are promising for ultrasensitive metrology as well as testing quantum mechanics. In this work, we investigate dissipative mechanical quantum state engineering in an optically levitated nanodiamond. First, we study single-mode mechanical squeezed states by magnetically coupling the mechanical motion to a dressed three-level system provided by a nitrogen-vacancy center in the nanoparticle. Quantum coherence between the dressed levels is created via microwave fields to induce a two-phonon transition, which results in mechanical squeezing. Remarkably, we find that in ultrahigh vacuum quantum squeezing is achievable at room temperature with feedback cooling. For moderate vacuum, quantum squeezing is possible with cryogenic temperature. Second, we present a setup for two mechanical modes coupled to the dressed three levels, which results in two-mode squeezing analogous to the mechanism of the single-mode case. In contrast to previous works, our study provides a deterministic method for engineering macroscopic squeezed states without the requirement for a cavity.

  13. The SH2 Domain Regulates c-Abl Kinase Activation by a Cyclin-Like Mechanism and Remodulation of the Hinge Motion

    OpenAIRE

    Dölker, N.; Górna, M. W.; Sutto, L.; Torralba, A. S.; Superti-Furga, G.; Gervasio, F. L.

    2014-01-01

    Regulation of the c-Abl (ABL1) tyrosine kinase is important because of its role in cellular signaling, and its relevance in the leukemiogenic counterpart (BCR-ABL). Both auto-inhibition and full activation of c-Abl are regulated by the interaction of the catalytic domain with the Src Homology 2 (SH2) domain. The mechanism by which this interaction enhances catalysis is not known. We combined computational simulations with mutagenesis and functional analysis to find that the SH2 domain conveys...

  14. Attention and apparent motion.

    Science.gov (United States)

    Horowitz, T; Treisman, A

    1994-01-01

    Two dissociations between short- and long-range motion in visual search are reported. Previous research has shown parallel processing for short-range motion and apparently serial processing for long-range motion. This finding has been replicated and it has also been found that search for short-range targets can be impaired both by using bicontrast stimuli, and by prior adaptation to the target direction of motion. Neither factor impaired search in long-range motion displays. Adaptation actually facilitated search with long-range displays, which is attributed to response-level effects. A feature-integration account of apparent motion is proposed. In this theory, short-range motion depends on specialized motion feature detectors operating in parallel across the display, but subject to selective adaptation, whereas attention is needed to link successive elements when they appear at greater separations, or across opposite contrasts.

  15. Macroscopic diffusion models for precipitation in crystalline gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Kimmerle, Sven-Joachim Wolfgang

    2009-09-21

    Based on a thermodynamically consistent model for precipitation in gallium arsenide crystals including surface tension and bulk stresses by Dreyer and Duderstadt, we propose two different mathematical models to describe the size evolution of liquid droplets in a crystalline solid. The first model treats the diffusion-controlled regime of interface motion, while the second model is concerned with the interface-controlled regime of interface motion. Our models take care of conservation of mass and substance. These models generalise the well-known Mullins- Sekerka model for Ostwald ripening. We concentrate on arsenic-rich liquid spherical droplets in a gallium arsenide crystal. Droplets can shrink or grow with time but the centres of droplets remain fixed. The liquid is assumed to be homogeneous in space. Due to different scales for typical distances between droplets and typical radii of liquid droplets we can derive formally so-called mean field models. For a model in the diffusion-controlled regime we prove this limit by homogenisation techniques under plausible assumptions. These mean field models generalise the Lifshitz-Slyozov-Wagner model, which can be derived from the Mullins-Sekerka model rigorously, and is well understood. Mean field models capture the main properties of our system and are well adapted for numerics and further analysis. We determine possible equilibria and discuss their stability. Numerical evidence suggests in which case which one of the two regimes might be appropriate to the experimental situation. (orig.)

  16. Mechanics of machinery

    CERN Document Server

    Mostafa, Mahmoud A

    2012-01-01

    MechanismsDefinitions Degrees of Freedom of Planar Mechanisms Four-Revolute-Pairs Chains Single-Slider Chain Double-Slider Mechanisms Mechanisms with Higher Pairs Compound Mechanisms Special Mechanisms Analytical Position Analysis of Mechanisms Velocities and AccelerationsAbsolute Plane Motion of a Particle Relative Motion Applications to Common Links Analysis of Mechanisms: Graphical Method Method of Instantaneous Centers for Determining the VelocitiesAnalytical Analysis CamsIntroduction Types of Cams Modes of Input/Output Motion Follower Configurations Classes of Cams Spur GearsIntroduction

  17. Structured pathology reporting improves the macroscopic assessment of rectal tumour resection specimens.

    Science.gov (United States)

    King, Simon; Dimech, Margaret; Johnstone, Susan

    2016-06-01

    We examined whether introduction of a structured macroscopic reporting template for rectal tumour resection specimens improved the completeness and efficiency in collecting key macroscopic data elements. Fifty free text (narrative) macroscopic reports retrieved from 2012 to 2014 were compared with 50 structured macroscopic reports from 2013 to 2015, all of which were generated at John Hunter Hospital, Newcastle, NSW. The six standard macroscopic data elements examined in this study were reported in all 50 anatomical pathology reports using a structured macroscopic reporting dictation template. Free text reports demonstrated significantly impaired data collection when recording intactness of mesorectum (p<0.001), relationship to anterior peritoneal reflection (p=0.028) and distance of tumour to the non-peritonealised circumferential margin (p<0.001). The number of words used was also significantly (p<0.001) reduced using pre-formatted structured reports compared to free text reports. The introduction of a structured reporting dictation template improves data collection and may reduce the subsequent administrative burden when macroscopically evaluating rectal resections. Copyright © 2016 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.

  18. Relationship Between Filler-Matrix Interface and Macroscopical Properties of Polymer Nanocomposites

    KAUST Repository

    Aguilar Ventura, Isaac Enrique

    2017-11-01

    The macroscopic properties of Multiwall Carbon Nanotube (MWCNT) polymer nano-composites and multiscale composites have been studied from a multifunctional standpoint. The objective is to understand and correlate the mechanisms in which the addition of a small content of MWCNTs can affect the mechanical, thermal and electrical properties of thermoplastic and thermoset polymer nanocomposites. While CNTs are well-known to possess extraordinary properties in the nanoscale, it has been shown that, the CNT/polymer matrix and CNT/CNT interactions are mainly responsible for the modification of properties in the nanocomposites. Observation of the mechanical properties revealed that the addition of CNTs can increase the stiffness of the material, but the increment of interfacial regions can accelerate the damage process under cyclic loading conditions. Additionally, CNTs can interact with polymer chains in the matrix affecting thermomechanical properties such as the glass transition temperature and the storage modulus. A low content of well-dispersed CNTs can form percolated networks within the matrix, which, due to the nature of the electrical conduction mechanism, have demonstrated potential in increasing the electrical conductivity of the nanocomposites. In contrast, high phonon scattering at the interconnections along the CNT network are responsible for marginal increases in thermal conductivity. In this study, a special focus was placed in modifying the CNT interconnections with a conductive polymer "bridge" to increase the efficiency of the electrical carrier transport. Additional experimental observations such as piezoresistivity and electrical conductivity/temperature dependency, demonstrated the major role of the interfacial regions with respect to the observed material properties in the macroscale. Controlling the interactions that occur in these regions is key to achieve tailorable, multifunctional nanocomposites.

  19. Objects in Motion

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    One thing scientists study is how objects move. A famous scientist named Sir Isaac Newton (1642-1727) spent a lot of time observing objects in motion and came up with three laws that describe how things move. This explanation only deals with the first of his three laws of motion. Newton's First Law of Motion says that moving objects will continue…

  20. Motion compensated digital tomosynthesis

    NARCIS (Netherlands)

    van der Reijden, Anneke; van Herk, Marcel; Sonke, Jan-Jakob

    2013-01-01

    Digital tomosynthesis (DTS) is a limited angle image reconstruction method for cone beam projections that offers patient surveillance capabilities during VMAT based SBRT delivery. Motion compensation (MC) has the potential to mitigate motion artifacts caused by respiratory motion, such as blur. The