Vacuum fluctuations in theories with deformed dispersion relations
Arzano, Michele; Magueijo, Joao; Amelino-Camelia, Giovanni
2015-01-01
We examine vacuum fluctuations in theories with modified dispersion relations which represent dimensional reduction at high energies. By changing units of energy and momentum we can obtain a description rendering the dispersion relations undeformed and transferring all the non-trivial effects to the integration measure in momentum space. Using this description we propose a general quantization procedure, which should be applicable whether or not the theory explicitly introduces a preferred frame. Based on this scheme we evaluate the power spectrum of quantum vacuum fluctuations. We find that in {\\it all} theories which run to 2 dimensions in the ultraviolet the vacuum fluctuations, in the ultraviolet regime, are scale-invariant. This is true in flat space but also for "inside the horizon" modes in an expanding universe. We spell out the conditions upon the gravity theory for this scale-invariance to be preserved as the modes are frozen-in outside the horizon. We also digress on the meaning of dimensionality (...
Bojowald, Martin
2013-01-01
Deformed special relativity is embedded in deformed general relativity using the methods of canonical relativity and loop quantum gravity. Phase-space dependent deformations of symmetry algebras then appear, which in some regimes can be rewritten as non-linear Poincare algebras with momentum-dependent deformations of commutators between boosts and time translations. In contrast to deformed special relativity, the deformations are derived for generators with an unambiguous physical role, following from the relationship between canonical constraints of gravity with stress-energy components. The original deformation does not appear in momentum space and does not give rise to non-locality issues or problems with macroscopic objects. Contact with deformed special relativity may help to test loop quantum gravity or restrict its quantization ambiguities.
Deformation behavior of dispersion-strengthened copper at high temperature
Institute of Scientific and Technical Information of China (English)
WANG Mengjun; ZHANG Yingchun; LUO Yun; LIU Xinyu
2006-01-01
The deformation behavior of dispersion-strengthened copper with different compositions was investigated by hot compression simulation tests on a Gleeble-1500 thermal-mechanical simulator. The microstructure during deformation at high temperature was also studied. The result shows that at the beginning of hot compression simulation, the flowing stress of the dispersion-strengthened copper quickly attains a peak value and the stress shows a greater decrease when the temperature is higher and the strain rate is lower. The dispersion particles lead to an obvious increase in the recrystallization temperature. Under experimental conditions, dynamic recovery is the main softening method. The constitutive equation at high temperature of 1.2%Al2O3-0.4%WC/Cu is obtained.
Physics of Deformed Special Relativity
Girelli, F; Girelli, Florian; Livine, Etera R.
2004-01-01
In many different ways, Deformed Special Relativity (DSR) has been argued to provide an effective limit of quantum gravity in almost-flat regime. Unfortunately DSR is up to now plagued by many conceptual problems (in particular how it describes macroscopic objects) which forbids a definitive physical interpretation and clear predictions. Here we propose a consistent framework to interpret DSR. We extend the principle of relativity: the same way that Special Relativity showed us that the definition of a reference frame requires to specify its speed, we show that DSR implies that we must also take into account its mass. We further advocate a 5-dimensional point of view on DSR physics and the extension of the kinematical symmetry from the Poincare group to the Poincare-de Sitter group (ISO(4,1)). This leads us to introduce the concept of a pentamomentum and to take into account the renormalization of the DSR deformation parameter kappa. This allows the resolution of the "soccer ball problem" (definition of many-...
Deformed Special Relativity in a Canonical Framework
Ghosh, S; Ghosh, Subir; Pal, Probir
2007-01-01
In this paper we have studied the nature of kinematical and dynamical laws in $\\kappa $-Minkowski spacetime from a new perspective: the canonical phase space approach. We have introduced a new form of $\\kappa$-Minkowski phase space algebra from which we recover the $\\kappa$-extended finite Lorentz transformations derived in \\cite{kim}. This is a particular form of a Deformed Special Relativity model that admits a modified energy-momentum dispersion law as well as noncommutative $\\kappa$-Minkowski phase space. We show that this system can be completely mapped to a set of phase space variables that obey canonical (and {\\it{not}} $\\kappa$-Minkowski) phase space algebra and Special Relativity Lorentz transformation (and {\\it{not}} $\\kappa$-extended Lorentz transformation). We demonstrate the usefulness and simplicity of this approach through a number of applications both in classical and quantum mechanics. We also construct a Lagrangian for the $\\kappa$-particle.
Analysis of Wave Nonlinear Dispersion Relation
Institute of Scientific and Technical Information of China (English)
LI Rui-jie; TAO Jian-fu
2005-01-01
The nonlinear dispersion relations and modified relations proposed by Kirby and Hedges have the limitation of intermediate minimum value. To overcome the shortcoming, a new nonlinear dispersion relation is proposed. Based on the summarization and comparison of existing nonlinear dispersion relations, it can be found that the new nonlinear dispersion relation not only keeps the advantages of other nonlinear dispersion relations, but also significantly reduces the relative errors of the nonlinear dispersion relations for a range of the relative water depth of 1＜kh＜1.5 and has sufficient accuracy for practical purposes.
Fourth order deformed general relativity
Cuttell, Peter D
2014-01-01
Whenever the condition of anomaly freedom is imposed within the framework of effective approaches to loop quantum cosmology, one seems to conclude that a deformation of general covariance is required. Here, starting from a general deformation we regain an effective gravitational Lagrangian including terms up to fourth order in extrinsic curvature. We subsequently constrain the form of the corrections, and then investigate the conditions for the occurrence of a big bounce and the realisation of an inflationary era, in the presence of a perfect fluid or scalar field.
Dispersion relations for unphysical particles
Siringo, Fabio
2017-03-01
Generalized dispersion relations are discussed for unphysical particles, e.g. confined degrees of freedom that are not present in the physical spectra but can give rise to observable bound states. While in general the propagator of the unphysical particles can have complex poles and cannot be reconstructed from the knowledge of the imaginary part, under reasonable assumptions the missing piece of information is shown to be in the rational function that contains the poles and must be added to the integral representation. For pure Yang-Mills theory, the rational part and the spectral term are identified in the explicit analytical expressions provided by the massive expansion of the gluon propagator. The multi particle spectral term turns out to be very small and the simple rational part provides, from first principles, an approximate propagator that is equivalent to the tree-level result of simple phenomenological models like the refined Gribov-Zwanziger model.
Metric Gauge Fields in Deformed Special Relativity
Cardone, F; Petrucci, A
2014-01-01
We show that, in the framework of Deformed Special Relativity (DSR), namely a (four-dimensional) generalization of the (local) space-time struc- ture based on an energy-dependent "deformation" of the usual Minkowski geometry, two kinds of gauge symmetries arise, whose spaces either coin- cide with the deformed Minkowski space or are just internal spaces to it. This is why we named them "metric gauge theories". In the case of the internal gauge ?elds, they are a consequence of the deformed Minkowski space (DMS) possessing the structure of a generalized Lagrange space. Such a geometrical structure allows one to de?ne curvature and torsion in the DMS.
Dispersive deformations of hydrodynamic reductions of (2 + 1)D dispersionless integrable systems
Ferapontov, E. V.; Moro, A.
2009-01-01
We demonstrate that hydrodynamic reductions of dispersionless integrable systems in 2 + 1 dimensions, such as the dispersionless Kadomtsev-Petviashvili (dKP) and dispersionless Toda lattice (dTl) equations, can be deformed into reductions of the corresponding dispersive counterparts. Modulo the Miura group, such deformations are unique. The requirement that any hydrodynamic reduction possesses a deformation of this kind imposes strong constraints on the structure of dispersive terms, suggesting an alternative approach to the integrability in 2 + 1 dimensions.
A Deformation Model for Dispersely Failing Elastoplastic Unidirectionally Reinforced Composites
Lagzdins, A.
2001-09-01
A calculation model is proposed for unidirectionally reinforced elastoplastic composites capable of gradually accumulating disperse microdamages under loading. The composite is assumed to be a homogeneous transversely isotropic solid. To describe its elastoplastic behavior, an incremental plasticity theory with a nonlinear combined hardening mechanism is invoked. At each point of the solid, its damage is characterized by a centrally symmetric scalar function on a unit sphere. This function is approximated by a fourth-rank tensor, which is used for describing the degradation of the elastic properties of the solid due to the accumulation of disperse microdamages. It is shown how to determine, using the known experimental data, all material constants appearing in the theoretical relations suggested.
A simplified algorithm for measuring erythrocyte deformability dispersion by laser ektacytometry
Energy Technology Data Exchange (ETDEWEB)
Nikitin, S Yu; Yurchuk, Yu S [Department of Physics, M.V. Lomonosov Moscow State University (Russian Federation)
2015-08-31
The possibility of measuring the dispersion of red blood cell deformability by laser diffractometry in shear flow (ektacytometry) is analysed theoretically. A diffraction pattern parameter is found, which is sensitive to the dispersion of erythrocyte deformability and to a lesser extent – to such parameters as the level of the scattered light intensity, the shape of red blood cells, the concentration of red blood cells in the suspension, the geometric dimensions of the experimental setup, etc. A new algorithm is proposed for measuring erythrocyte deformability dispersion by using data of laser ektacytometry. (laser applications in medicine)
Planck-scale-modified dispersion relations in FRW spacetime
Rosati, Giacomo; Marciano, Antonino; Matassa, Marco
2015-01-01
In recent years Planck-scale modifications of the dispersion relation have been attracting increasing interest also from the viewpoint of possible applications in astrophysics and cosmology, where spacetime curvature cannot be neglected. Nonetheless the interplay between Planck-scale effects and spacetime curvature is still poorly understood, particularly in cases where curvature is not constant. These challenges have been so far postponed by relying on an ansatz, first introduced by Jacob and Piran. We here propose a general strategy of analysis of the effects of modifications of dispersion relation in FRW spacetimes, applicable both to cases where the relativistic equivalence of frames is spoiled ("preferred-frame scenarios") and to the alternative possibility of "DSR-relativistic theories", theories that are fully relativistic but with relativistic laws deformed so that the modified dispersion relation is observer independent. We show that the Jacob-Piran ansatz implicitly assumes that spacetime translatio...
Phonon dispersion relation of liquid metals
Indian Academy of Sciences (India)
P B Thakor; P N Gajjar; A R Jani
2009-06-01
The phonon dispersion curves of some liquid metals, viz. Na ( = 1), Mg ( = 2), Al ( = 3) and Pb ( = 4), have been computed using our model potential. The charged hard sphere (CHS) reference system is applied to describe the structural information. Our model potential along with CHS reference system is capable of explaining the phonon dispersion relation for monovalent, divalent, trivalent and tetravalent liquid metals.
Nonlinear Dispersion Relation in Wave Transformation
Institute of Scientific and Technical Information of China (English)
李瑞杰; 严以新; 曹宏生
2003-01-01
A nonlinear dispersion relation is presented to model the nonlinear dispersion of waves over the whole range of possible water depths. It reduces the phase speed over-prediction of both Hedges′ modified relation and Kirby and Dalrymple′s modified relation in the region of 1＜kh＜1.5 for small wave steepness and maintains the monotonicity in phase speed variation for large wave steepness. And it has a simple form. By use of the new nonlinear dispersion relation along with the mild slope equation taking into account weak nonlinearity, a mathematical model of wave transformation is developed and applied to laboratory data. The results show that the model with the new dispersion relation can predict wave transformation over complicated bathymetry satisfactorily.
Commutative deformations of general relativity: nonlocality, causality, and dark matter
Energy Technology Data Exchange (ETDEWEB)
De Vegvar, P.G.N. [SWK Research, Bellingham, WA (United States)
2017-01-15
Hopf algebra methods are applied to study Drinfeld twists of (3+1)-diffeomorphisms and deformed general relativity on commutative manifolds. A classical nonlocality length scale is produced above which microcausality emerges. Matter fields are utilized to generate self-consistent Abelian Drinfeld twists in a background independent manner and their continuous and discrete symmetries are examined. There is negligible experimental effect on the standard model of particles. While baryonic twist producing matter would begin to behave acausally for rest masses above ∝1-10 TeV, other possibilities are viable dark matter candidates or a right-handed neutrino. First order deformed Maxwell equations are derived and yield immeasurably small cosmological dispersion and produce a propagation horizon only for photons at or above Planck energies. This model incorporates dark matter without any appeal to extra dimensions, supersymmetry, strings, grand unified theories, mirror worlds, or modifications of Newtonian dynamics. (orig.)
Commutative deformations of general relativity: nonlocality, causality, and dark matter
de Vegvar, P G N
2016-01-01
Hopf algebra methods are applied to study Drinfeld twists of (3+1)-diffeomorphisms and deformed general relativity on \\emph{commutative} manifolds. A classical nonlocality length scale is produced above which standard light cone causality emerges. We introduce a sector of matter fields to generate selfconsistent Abelian Drinfeld twists in a background independent manner and study their discrete and gauge symmetries. They naturally give rise to dark matter candidates, possibly including ground state condensates. First order deformed Maxwell equations are derived and yield negligible cosmological dispersion and produce a propagation horizon only for photons approaching Planck energies. This model incorporates dark matter without any appeal to extra dimensions, supersymmetry, strings, branes, mirror worlds, or modifications of Newtonian dynamics.
Reappraisal of a model for deformed special relativity
Gubitosi, Giulia
2015-01-01
We revisit one of the earliest proposals for deformed dispersion relations in the light of recent results on dynamical dimensional reduction and production of cosmological fluctuations. Depending on the specification of the measure of integration and addition rule in momentum space the model may be completed so as to merely deform Lorentz invariance, or so as to introduce a preferred frame. Models which violate Lorentz invariance have a negative UV asymptotic dimension and a very red spectrum of quantum vacuum fluctuations. Instead, models which preserve frame independence can exhibit running to a UV dimension of 2, and a scale-invariant spectrum of fluctuations. The bispectrum of the fluctuations is another point of divergence between the two casings proposed here for the original model.
Planck-scale-modified dispersion relations in homogeneous and isotropic spacetimes
Barcaroli, Leonardo; Brunkhorst, Lukas K.; Gubitosi, Giulia; Loret, Niccoló; Pfeifer, Christian
2017-01-01
The covariant understanding of dispersion relations as level sets of Hamilton functions on phase space enables us to derive the most general dispersion relation compatible with homogeneous and isotropic spacetimes. We use this concept to present a Planck-scale deformation of the Hamiltonian of a particle in Friedman-Lemaître-Robertson-Walker (FLRW) geometry that is locally identical to the κ -Poincaré dispersion relation, in the same way as the dispersion relation of point particles in general relativity is locally identical to the one valid in special relativity. Studying the motion of particles subject to such a Hamiltonian, we derive the redshift and lateshift as observable consequences of the Planck-scale deformed FLRW universe.
Dispersion relations in heavily-doped nanostructures
Ghatak, Kamakhya Prasad
2016-01-01
This book presents the dispersion relation in heavily doped nano-structures. The materials considered are III-V, II-VI, IV-VI, GaP, Ge, Platinum Antimonide, stressed, GaSb, Te, II-V, HgTe/CdTe superlattices and Bismuth Telluride semiconductors. The dispersion relation is discussed under magnetic quantization and on the basis of carrier energy spectra. The influences of magnetic field, magneto inversion, and magneto nipi structures on nano-structures is analyzed. The band structure of optoelectronic materials changes with photo-excitation in a fundamental way according to newly formulated electron dispersion laws. They control the quantum effect in optoelectronic devices in the presence of light. The measurement of band gaps in optoelectronic materials in the presence of external photo-excitation is displayed. The influences of magnetic quantization, crossed electric and quantizing fields, intense electric fields on the on the dispersion relation in heavily doped semiconductors and super-lattices are also disc...
String theories with deformed energy momentum relations, and a possible non-tachyonic bosonic string
Magueijo, J; Magueijo, Joao; Smolin, Lee
2004-01-01
We consider a prescription for introducing deformed dispersion relations in the bosonic string action. We find that in a subset of such theories it remains true that the embedding coordinates propagate linearly on the worldsheet. While both the string modes and the center of mass propagate with deformed dispersion relations, the speed of light remains energy independent. We consider the canonical quantization of these strings, and find that it is possible to choose theories so that ghost modes still decouple, as usual. However the Virasoro algebra now exhibits an energy dependent central charge. We also find that there are examples where the tachyon is eliminated from the spectrum of the free bosonic string.
Near Scale Invariance with Modified Dispersion Relations
Armendariz-Picon, C
2006-01-01
We describe a novel mechanism to seed a nearly scale invariant spectrum of adiabatic perturbations during a non-inflationary stage. It relies on a modified dispersion relation that contains higher powers of the spatial momentum of matter perturbations. We implement this idea in the context of a massless scalar field in an otherwise perfectly homogeneous universe. The couplings of the field to background scalars and tensors give rise to the required modification of its dispersion relation, and the couplings of the scalar to matter result in an adiabatic primordial spectrum. This work is meant to explicitly illustrate that it is possible to seed nearly scale invariant primordial spectra without inflation, within a conventional expansion history.
On the Klein-Gordon equation using the dispersion relation of Doubly Special Relativity
Felipe, Yese J.
2017-01-01
The theory of Doubly Special Relativity or Deformed Special Relativity (DSR), proposes that there is a maximum energy scale and a minimum length scale that is invariant for all observers. These maximum energy and minimum length correspond to the Planck energy and the Planck length, respectively. As a consequence, the dispersion relation is modified to be E2 =p2c2 +m2c4 + λE3 + ... Previous work has been done to express Quantum Mechanics using the dispersion relation of DSR. Solutions of the free particle, the harmonic oscillator, and the Hydrogen atom have been obtained from the DSR Schrodinger equation. We explore how the DSR Klein-Gordon equation can be consistently approximated in the non-relativistic limit in order to derive the DSR Schrodinger equation.
Inflationary cosmology with nonlinear dispersion relations
Zhu, Tao; Cleaver, Gerald; Kirsten, Klaus; Sheng, Qin
2013-01-01
We present a technique, {\\em the uniform asymptotic approximation}, to construct accurate analytical solutions of the linear perturbations of inflation after quantum effects of the early universe are taken into account, for which the dispersion relations generically become nonlinear. We construct explicitly the error bounds associated with the approximations and then study them in detail. With the understanding of the errors and the proper choice of the Liouville transformations of the differential equations of the perturbations, we show that the analytical solutions describe the exact evolution of the linear perturbations extremely well even only to the first-order approximations. As a simple application of the approximate analytical solutions, we calculate the power spectra and indices of scalar and tensor perturbations in the de Sitter background, and find that the amplitudes of the power spectra get modified due to the quantum effects, while the power spectrum indices remain the same as in the linear case...
DEFF Research Database (Denmark)
Zhang, Zhenbo
fission and fusion reactors. In this study, two candidate steels for nuclear reactors, namely a ferritic/martensitic steel (modified 9Cr-1Mo steel) and an oxide dispersion strengthened (ODS) ferritic steel (PM2000), were nanostructured by dynamic plastic deformation (DPD). The resulting microstructure...... place, when both steels after DPD are annealed. Both oriented nucleation and oriented growth of oriented lamellae are demonstrated to account for such an orientation dependence. The underlying mechanisms are discussed, including the differences in stored energy, structural variation, and recovery...
Three kinds of nonlinear dispersive waves in elastic rods with finite deformation
Institute of Scientific and Technical Information of China (English)
ZHANG Shan-yuan; LIU Zhi-fang
2008-01-01
On the basis of classical linear theory on longitudinal, torsional and flexural waves in thin elastic rods, and taking finite deformation and dispersive effects into consideration, three kinds of nonlinear evolution equations are derived. Qualitative analysis of three kinds of nonlinear equations are presented. It is shown that these equations have homoclinic or heteroclinic orbits on the phase plane, corresponding to solitary wave or shock wave solutions, respectively. Based on the principle of homogeneous balance, these equations are solved with the Jacobi elliptic function expansion method. Results show that existence of solitary wave solution and shock wave solution is possible under certain conditions. These conclusions are consistent with qualitative analysis.
f-Deformed Boson Algebra Related to Gentile Statistics
Chung, Won Sang; Hassanabadi, Hassan
2017-06-01
In this paper the deformed boson algebra giving the Gentile distribution function is constructed by using the model of ideal gas of deformed bosons and some properties of a root of unity. As an example we discuss the quantum optical problem related to the Gentile (or f-deformed) boson algebra with large but finite M. For this algebra we construct the Gentile (or f-deformed) coherent state and discuss its nonclassical properties such as sub-Poissonian statistics and anti-bunching effect.
Functional crossover in the dispersion relations of magnons and phonons
Hoser, A.; Köbler, U.
2016-09-01
Experimental data are presented showing that the dispersion relations of magnons and acoustic phonons can consist of two sections with different functions of wave vector. In the low wave vector range a power function of wave vector often holds over a finite q-range while dispersions for larger wave vector values better approach the atomistic model predictions. In the magnon spectra ∼⃒qx power functions with exponents x=1.25, 1.5 and 2 are identified. The dispersion of the acoustic phonons can be a linear function of wave vector over a surprisingly large range of energy. Since the slope of the linear section agrees with the known sound velocities it can be concluded that the dispersion of the acoustic phonons has got attracted by the linear dispersion of the mass less Debye bosons (sound waves). Due to the different (translational) symmetries of bosons and atomistic excitations (magnons, phonons) the associated dispersions can attract each other. In the same way the different ∼⃒qx power functions in the magnon dispersions indicate that magnon dispersions are attracted by the dispersion of the bosons of the magnetic continuum (Goldstone bosons). This allows evaluation of the otherwise difficult to obtain dispersions of the Goldstone bosons from the known magnon dispersions. Interestingly, the dispersions of Goldstone bosons (Debye bosons) attract magnon dispersions (phonon dispersions) and not vice versa.
Physics of Deformed Special Relativity: Relativity Principle revisited
Girelli, F; Girelli, Florian; Livine, Etera R.
2004-01-01
In many different ways, Deformed Special Relativity (DSR) has been argued to provide an effective limit of quantum gravity in almost-flat regime. Some experiments will soon be able to test some low energy effects of quantum gravity, and DSR is a very promising candidate to describe these latter. Unfortunately DSR is up to now plagued by many conceptual problems (in particular how it describes macroscopic objects) which forbids a definitive physical interpretation and clear predictions. Here we propose a consistent framework to interpret DSR. We extend the principle of relativity: the same way that Special Relativity showed us that the definition of a reference frame requires to specify its speed, we show that DSR implies that we must also take into account its mass. We further advocate a 5-dimensional point of view on DSR physics and the extension of the kinematical symmetry from the Poincare group to the Poincare-de Sitter group (ISO(4,1)). This leads us to introduce the concept of a pentamomentum and to tak...
Moving Schwarzschild Black Hole and Modified Dispersion Relations
Hinojosa, Cristian Barrera
2015-01-01
We study the thermodynamics of a moving Schwarzschild black hole, identifying the temperature and entropy in a relativistic scenario. Furthermore, we set arguments in a framework relating invariant geometrical quantities under global spacetime transformations and the dispersion relation of the system. We then extended these arguments in order to consider more general dispersion relations, and identify criteria to rule them out.
Moving Schwarzschild black hole and modified dispersion relations
Directory of Open Access Journals (Sweden)
Cristian Barrera Hinojosa
2015-10-01
Full Text Available We study the thermodynamics of a moving Schwarzschild black hole, identifying the temperature and entropy in a relativistic scenario. Furthermore, we set arguments in a framework relating invariant geometrical quantities under global spacetime transformations and the dispersion relation of the system. We then extended these arguments in order to consider more general dispersion relations, and identify criteria to rule them out.
Dispersion relations for 1D high-gain FELs
Energy Technology Data Exchange (ETDEWEB)
Webb, S.D.; Litvinenko, V.N.
2010-08-23
We present analytical results for the one-dimensional dispersion relation for high-gain FELs. Using kappa-n distributions, we obtain analytical relations between the dispersion relations for various order kappa distributions. Since an exact solution exists for the kappa-1 (Lorentzian) distribution, this provides some insight into the number of modes on the way to the Gaussian distribution.
Dispersion relations for circular single and double dusty plasma chains
Tkachenko, D V; Misko, V R
2011-01-01
We derive dispersion relations for a system of identical particles confined in a two-dimensional annular harmonic well and which interact through a Yukawa potential, e.g., a dusty plasma ring. When the particles are in a single chain (i.e., a one-dimensional ring) we find a longitudinal acoustic mode and a transverse optical mode which show approximate agreement with the dispersion relation for a straight configuration for large radii of the ring. When the radius decreases, the dispersion relations modify: there appears an anticrossing of the modes near the crossing point resulting in a frequency gap between the lower and upper branches of the modified dispersion relations. For the double chain (i.e., a two-dimensional zigzag configuration) the dispersion relation has four branches: longitudinal acoustic and optical and transverse acoustic and optical.
Rainbows without unicorns: Metric structures in theories with Modified Dispersion Relations
Lobo, Iarley P; Nettel, Francisco
2016-01-01
"Rainbow" metrics are a widely used approach to metric formalism for theories with Modified Dispersion Relations. They have had a huge success in the Quantum Gravity Phenomenology literature, since they allow to introduce momentum-dependent spacetime metrics into the description of systems with Modified Dispersion Relation. This approach, however, presents some compatibility issues with a relativistic description, even in the case of introducing deformed spacetime symmetries to keep the theory's modified dispersion relation invariant. In this paper we would like to introduce the readers to this issue and to describe how the relativistic properties of the theory can be recovered taking into account a more complex (but also complete) momentum-space curvature framework. We also introduce a new metric structure from a Polyakov-like description of the action.
Angularly Deformed Special Relativity and its Results for Quantum Mechanics
Glinka, Lukasz Andrzej
2015-01-01
In this paper, the deformed Special Relativity, which leads to an essentially new theoretical context of quantum mechanics, is presented. The formulation of the theory arises from a straightforward analogy with the Special Relativity, but its foundations are laid through the hypothesis on breakdown of the velocity-momentum parallelism which affects onto the Einstein equivalence principle between mass and energy of a relativistic particle. Furthermore, the derivation is based on the technique of an eikonal equation whose well-confirmed physical role lays the foundations of both optics and quantum mechanics. As a result, we receive the angular deformation of Special Relativity which clearly depicts the new deformation-based theoretical foundations of physics, and, moreover, offers both constructive and consistent phenomenological discussion of the theoretical issues such like imaginary mass and formal superluminal motion predicted in Special Relativity for this case. In the context of the relativistic theory, p...
Characterization of thin films using generalized lamb wave dispersion relations
Richard, P; Behrend, O.; Gremaud, G.; Kulik, A.
1993-01-01
We used the Continuous Wave Scanning Acoustic Microscope to characterize thin film materials. The measurement of the dispersion curve of surface waves and the inversion of this dispersion equation relation, allow to determine the elastic constants, the density or the thickness of a thin layer on a substrate. Besides, it is possible to have qualitative information on the adhesion properties of the layer.
RELATIVE MOTION AND DEFORMATION OF PACIFIC PLATE FROM SPACE GEODESY
Institute of Scientific and Technical Information of China (English)
JinShuanggen; ZhuWenyao
2003-01-01
The circum-Pacific tectonic system that contains of convergent, divergent and transform boundaries, is the most active region of volcanoes and earthquakes in the world, and involves many important theoretical questions in geosciences. The relative motion and deformation of Pacific plate is still an active subject of research. In this note, we analyze the deformation of Pacific plate and obtain reliable results of the relative motion rates at the circum-Pacific boundaries based on space geodetic data, which reveals the present-day motion characteristics of Pacific plate.
STUDY ON DYNAMIC CONSTITUTIVE RELATIONS FOR CONCRETE WITH FINITE DEFORMATION
Institute of Scientific and Technical Information of China (English)
陈书宇; 沈成康; 金吾根
2004-01-01
The differences between finite deformation and infinitesimal deformation are discussed. They are exercised on elasto-viscoplastic constitutive relations of concrete.Then, a rate-dependent mechanics model was presented on the basis of Ottosen' s fourparameter yield criterion, where different loading surface transferring laws were taken into account, when material was in hardening stage or in softening stage, respectively. The model is well established, so that it can be applied to simulate the response of concrete subject to impact loading. Green-Naghdi stress rate was introduced as objective stress rate.Appropriate hypothesis was postulated in accordance with many experimental results, which could reflect the mechanical behaviour of concrete with large deformation. Available thoughts as well as effective methods are also provided for the research on related engineering problems.
Transplanckian dispersion relation and entanglement entropy of blackhole
Energy Technology Data Exchange (ETDEWEB)
Chang, D. [Department of Physics, National Tsing-Hua University, Hsin-Chu (Taiwan); Chu, C.S.; Lin, F.L. [Physics Division, National Center for Theoretical Sciences, National Tsing-Hua University, Hsin-Chu (Taiwan)
2004-06-01
The quantum correction to the entanglement entropy of the event horizon is plagued by the UV divergence due to the infinitely blue-shifted near horizon modes. The resolution of this UV divergence provides an excellent window to a better understanding and control of the quantum gravity effects. We claim that the key to resolve this UV puzzle is the transplanckian dispersion relation. We calculate the entanglement entropy using a very general type of transplanckian dispersion relation such that high energy modes above a certain scale are cutoff, and show that the entropy is rendered UV finite. We argue that modified dispersion relation is a generic feature of string theory, and this boundedness nature of the dispersion relation is a general consequence of the existence of a minimal distance in string theory. (Abstract Copyright [2004], Wiley Periodicals, Inc.)
Phonons in slow motion: dispersion relations in ultrathin Si membranes.
Cuffe, John; Chávez, Emigdio; Shchepetov, Andrey; Chapuis, Pierre-Olivier; El Boudouti, El Houssaine; Alzina, Francesc; Kehoe, Timothy; Gomis-Bresco, Jordi; Dudek, Damian; Pennec, Yan; Djafari-Rouhani, Bahram; Prunnila, Mika; Ahopelto, Jouni; Sotomayor Torres, Clivia M
2012-07-11
We report the changes in dispersion relations of hypersonic acoustic phonons in free-standing silicon membranes as thin as ∼8 nm. We observe a reduction of the phase and group velocities of the fundamental flexural mode by more than 1 order of magnitude compared to bulk values. The modification of the dispersion relation in nanostructures has important consequences for noise control in nano- and microelectromechanical systems (MEMS/NEMS) as well as opto-mechanical devices.
Dispersion relation of excitation mode in strongly interacting fermions matter
Institute of Scientific and Technical Information of China (English)
Wang Yan-Ping; Chen Ji-Sheng
2008-01-01
This paper analyses the dispersion relation of the excitation mode in non-relativistic interacting fermion matter.The polarization tensor is calculated with the random phase approximation in terms of finite temperature field theory.With the polarization tensor, the influences of temperature, particle number density and interaction strength on the dispersion relation are discussed in detail. It finds that the collective effects are qualitatively more important in the unitary fermions than those in the finite contact interaction matter.
A brief Introduction to Dispersion Relations and Analyticity
Zwicky, Roman
2016-01-01
In these lectures we provide a basic introduction into the topic of dispersion relation and analyticity. The properties of 2-point functions are discussed in some detail from the viewpoint of the K\\"all\\'en-Lehmann and general dispersion relations. The Weinberg sum rules figure as an application. The analytic structure of higher point functions in perturbation theory are analysed through the Landau equations and the Cutkosky rules.
High-temperature deformation of dispersion-strengthened Cu-Zr-Ti-C alloys
Energy Technology Data Exchange (ETDEWEB)
Palma, Rodrigo H. [Departamento de Ingenieria Mecanica, Universidad de Chile, Beauchef 850, 4 deg. Piso, Santiago 6511261 (Chile)]. E-mail: rhpalma@ing.uchile.ct; Sepulveda, Aquiles [Departamento de Ingenieria Mecanica, Universidad de Chile, Beauchef 850, 4 deg. Piso, Santiago 6511261 (Chile); Espinoza, Rodrigo [Departamento de Ingenieria Mecanica, Universidad de Chile, Beauchef 850, 4 deg. Piso, Santiago 6511261 (Chile); Dianez, M. Jesus [Instituto de Ciencia de Materiales de Sevilla, Americo Vespucio s/n, Isla de La Cartuja, Sevilla (Spain); Criado, Jose M. [Instituto de Ciencia de Materiales de Sevilla, Americo Vespucio s/n, Isla de La Cartuja, Sevilla (Spain); Sayagues, M. Jesus [Instituto de Ciencia de Materiales de Sevilla, Americo Vespucio s/n, Isla de La Cartuja, Sevilla (Spain)
2005-01-25
The hot mechanical behaviour and microstructure of Cu-5 vol.% TiC, Cu-5 vol.% ZrO{sub 2} and Cu-2.5 vol.% TiC-2.5 vol.% ZrO{sub 2} alloys prepared by reaction milling were studied. After a test of 1 h annealing at 1173 K, the Cu-5 vol.% ZrO{sub 2} alloy presented the lower softening resistance to annealing, while the other two ones kept their initial room-temperature hardness (about 2 GPa). Hot-compression tests at 773 and 1123 K, at initial true strain rates of 0.85 x 10{sup -3} and 0.85 x 10{sup -4} s{sup -1} were performed. The Cu-2.5 vol.% TiC-2.5 vol.% ZrO{sub 2} and the Cu-5 vol.% ZrO{sub 2} alloys were the strongest and softest materials, respectively. Moreover, by electron microscopy, nanometric TiC and micrometric particles were detected in the Cu-5 vol.% TiC and Cu-5 vol.% ZrO{sub 2} alloys, respectively. A possible explanation for the observed behaviour of these materials is proposed. In the compression tests, it was also found that strain rate has a low effect on flow stress, as it has been previously observed by various authors in dispersion-strengthened alloys deformed at high temperatures.
Generalised integrable $\\lambda$- and $\\eta$-deformations and their relation
Sfetsos, Konstantinos; Thompson, Daniel C
2015-01-01
We construct two-parameter families of integrable $\\lambda$-deformations of two-dimensional field theories. These interpolate between a CFT (a WZW/gauged WZW model) and the non-Abelian T-dual of a principal chiral model on a group/symmetric coset space. In examples based on the $SU(2)$ WZW model and the $SU(2)/U(1)$ exact coset CFT, we show that these deformations are related to bi-Yang-Baxter generalisations of $\\eta$-deformations via Poisson-Lie T-duality and analytic continuation. We illustrate the quantum behaviour of our models under RG flow. As a byproduct we demonstrate that the bi-Yang-Baxter $\\sigma$-model for a general group is one-loop renormalisable.
Generalised integrable λ- and η-deformations and their relation
Directory of Open Access Journals (Sweden)
Konstantinos Sfetsos
2015-10-01
Full Text Available We construct two-parameter families of integrable λ-deformations of two-dimensional field theories. These interpolate between a CFT (a WZW/gauged WZW model and the non-Abelian T-dual of a principal chiral model on a group/symmetric coset space. In examples based on the SU(2 WZW model and the SU(2/U(1 exact coset CFT, we show that these deformations are related to bi-Yang–Baxter generalisations of η-deformations via Poisson–Lie T-duality and analytic continuation. We illustrate the quantum behaviour of our models under RG flow. As a byproduct we demonstrate that the bi-Yang–Baxter σ-model for a general group is one-loop renormalisable.
Understanding the relative role of dispersion mechanisms across basin scales
Di Lazzaro, M.; Zarlenga, A.; Volpi, E.
2016-05-01
Different mechanisms are understood to represent the primary sources of the variance of travel time distribution in natural catchments. To quantify the fraction of variance introduced by each component, dispersion coefficients have been earlier defined in the framework of geomorphology-based rainfall-runoff models. In this paper we compare over a wide range of basin sizes and for a variety of runoff conditions the relative role of geomorphological dispersion, related to the heterogeneity of path lengths, and hillslope kinematic dispersion, generated by flow processes within the hillslopes. Unlike previous works, our approach does not focus on a specific study case; instead, we try to generalize results already obtained in previous literature stemming from the definition of a few significant parameters related to the metrics of the catchment and flow dynamics. We further extend this conceptual framework considering the effects of two additional variance-producing processes: the first covers the random variability of hillslope velocities (i.e. of travel times over hillslopes); the second deals with non-uniform production of runoff over the basin (specifically related to drainage density). Results are useful to clarify the role of hillslope kinematic dispersion and define under which conditions it counteracts or reinforces geomorphological dispersion. We show how its sign is ruled by the specific spatial distribution of hillslope lengths within the basin, as well as by flow conditions. Interestingly, while negative in a wide range of cases, kinematic dispersion is expected to become invariantly positive when the variability of hillslope velocity is large.
Dispersion relations and the spin polarizabilities of the nucleon
Drechsel, D; Hanstein, O
1998-01-01
A forward dispersion calculation is implemented for the spin polarizabilities are related to the spin structure of the nucleon at low energies and are structure-constants of the Compton scattering amplitude at ${\\cal O}(\\omega^3)$. In the absence of a direct experimental measurement of these quantities, a dispersion calculation serves the purpose of constraining the model building, and of comparing with recent calculations in heavy baryon chiral perturbation theory.
Could the photon dispersion relation be non-linear ?
2008-01-01
The free photon dispersion relation is a reference quantity for high precision tests of Lorentz Invariance. We first outline theoretical approaches to a conceivable Lorentz Invariance Violation (LIV). Next we address phenomenological tests based on the propagation of cosmic rays, in particular in Gamma Ray Bursts (GRBs). As a specific concept, which could imply LIV, we then focus on field theory in a non-commutative (NC) space, and we present non-perturbative results for the dispersion relati...
The deformed uncertainty relation and the corresponding beam quality factor
Li, K; Wang, S M; Li, Kang; Zhao, Dao Mu; Wang, Shao Min
1996-01-01
By using the theory of deformed quantum mechanics, we study the deformed light beam theoretically. The deformed beam quality factor M_q^2 is given explicitly under the case of deformed light in coherent state. When the deformation parameter q being a root of unity, the beam quality factor M_q^2 \\leq 1.
Hamilton geometry: Phase space geometry from modified dispersion relations
Barcaroli, Leonardo; Gubitosi, Giulia; Loret, Niccoló; Pfeifer, Christian
2015-01-01
We describe the Hamilton geometry of the phase space of particles whose motion is characterised by general dispersion relations. In this framework spacetime and momentum space are naturally curved and intertwined, allowing for a simultaneous description of both spacetime curvature and non-trivial momentum space geometry. We consider as explicit examples two models for Planck-scale modified dispersion relations, inspired from the $q$-de Sitter and $\\kappa$-Poincar\\'e quantum groups. In the first case we find the expressions for the momentum and position dependent curvature of spacetime and momentum space, while for the second case the manifold is flat and only the momentum space possesses a nonzero, momentum dependent curvature. In contrast, for a dispersion relation that is induced by a spacetime metric, as in General Relativity, the Hamilton geometry yields a flat momentum space and the usual curved spacetime geometry with only position dependent geometric objects.
Psychosocial consequences of leprosy and the related deformity in Bangladesh
Directory of Open Access Journals (Sweden)
Qazi Azad-uz-zaman
2017-01-01
Full Text Available Objective: To explore the psychosocial condition and consequences of the people affected by leprosy and the related deformity in some selected areas of Bangladesh. Methods: A cross-sectional study was conducted from July to December 2015 among 92 leprosy-affected people. A pretested semi-structure questionnaire was used for collecting data by face to face interview from both the low prevalent areas of Khulna and the high prevalent area of Rangpur Division in Bangladesh. Results: Nearly two-fifth of respondents were observed having deformity. Among them, around four-fifth was from Khulna region, about half were above 50 years of age and more than half had monthly family income lower than 5 000 BDT. The development of deformity is found having highly significant association with region (P < 0.001, residence (P < 0.004, and family income (P < 0.004. Differences in consequences between ‘with deformity’ and ‘without deformity’ were found very high. About 65% of the respondents with deformity ‘think less’ of himself, and nearly 60% felt ashamed or embarrassed, 53% had to change job, and 47% was used to think having less respect in the society where the percentage was much lower in all cases to ‘without deformity’ group. Conclusions: Early diagnosis and start multidrug therapy at the earliest stages have chanced to reduce the leprosy-resulted deformity, disfigurement and disability. For those who already have had some nerve damages, health education is highly important to prevent further injury and hence psychosocial consequences.
Numerical calculation of dispersion relation for linear internal waves
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
With the horizontal Coriolis terms included in motion equations and the influence of compressibility of seawater on Brunt-V(a)is(a)l(a) frequency considered, a numerical method of calculating the dispersion relation for linear internal waves, which is an improvement of Cai and Gan (1995), and hence Fliegel and Hunkins (1975), had been set up. For different models (Pacific model, Atlantic model and Arctic model), simulations using the three different methods were compared and the following conclusions were reached: (1) the influence of horizontal Coriolis terms on dispersion relation cannot be neglected and is connected with the direction of the wave celerity, the latitude, and the modes of the wave;(2) the effect of compressibility of seawater in stratification is not an important factor for the dispersion relation of linear internal wave, at least for those three models. With the improved method, the wavefunction curves for the Pacific model had also been built.
Further Analysis of ππ Scattering Dispersion Relations
Xiao, Zhi-Guang; Zheng, Han-Qing
2003-03-01
The naive use of higher-order perturbation theory leads to the left-hand cut integrals in pipi dispersion relations [Phys. Lett. B 536 (2002) 59; B 549 (2002) 362; Nucl. Phys. A 695 (2001) 273] to be divergent. This problem is discussed and solved. We point out that the Adler zero condition imposes three constraints on the dispersion relations. The sigma pole position is determined using the improved method, Msigma = 483±13 MeV, Gammasigma = 705±50 MeV. The scattering length parameter is found to be in excellent agreement with the experimental result.
Geometrical origin of the energy-momentum dispersion relation
Watcharangkool, Apimook
2016-01-01
We investigate a link between the energy-momentum dispersion relation and the spectral distance in the context of a Lorentzian almost-commutative spectral geometry, defined by the product of Minkowski spacetime and an internal discrete noncommutative space. Using the causal structure, the almost-commutative manifold can be identified with a pair of four-dimensional Minkowski spacetimes embedded in a five-dimensional Minkowski geometry. Considering fermions travelling within the light cone of the ambient five-dimensional spacetime, we then derive the energy-momentum dispersion relation.
Noncommutative geometrical origin of the energy-momentum dispersion relation
Watcharangkool, A.; Sakellariadou, M.
2017-01-01
We investigate a link between the energy-momentum dispersion relation and the spectral distance in the context of a Lorentzian almost-commutative spectral geometry, defined by the product of Minkowski spacetime and an internal discrete noncommutative space. Using the causal structure, the almost-commutative manifold can be identified with a pair of four-dimensional Minkowski spacetimes embedded in a five-dimensional Minkowski geometry. Considering fermions traveling within the light cone of the ambient five-dimensional spacetime, we then derive the energy-momentum dispersion relation.
A linearized dispersion relation for orthorhombic pseudo-acoustic modeling
Song, Xiaolei
2012-11-04
Wavefield extrapolation in acoustic orthorhombic anisotropic media suffers from wave-mode coupling and stability limitations in the parameter range. We introduce a linearized form of the dispersion relation for acoustic orthorhombic media to model acoustic wavefields. We apply the lowrank approximation approach to handle the corresponding space-wavenumber mixed-domain operator. Numerical experiments show that the proposed wavefield extrapolator is accurate and practically free of dispersions. Further, there is no coupling of qSv and qP waves, because we use the analytical dispersion relation. No constraints on Thomsen\\'s parameters are required for stability. The linearized expression may provide useful application for parameter estimation in orthorhombic media.
Dispersion relations of strained as well as complex Lieb lattices
Zhang, Yiqi; Zhong, Weiping; Li, Changbiao; Chen, Haixia; Zhang, Yanpeng
2015-01-01
We investigate the dispersion relations of strained as well as complex Lieb lattices systematically based on the tight-binding method when the nearest-neighbor approximation is adopted. We find that edge states will no appear for strained Lieb lattices and $\\mathcal{PT}$-symmetry Lieb lattice cannot be obtained.
Engineering plasmon dispersion relations : hybrid nanoparticle chain - substrate plasmon polaritons
Compaijen, Paul J.; Malyshev, Victor A.; Knoester, Jasper
2015-01-01
We consider the dispersion relations of the optical excitations in a chain of silver nanoparticles situated above a metal substrate and show that they are hybrid plasmon polaritons, composed of localized surface plasmons and surface plasmon polaritons. We demonstrate a strong dependence of the syste
Fock representations of Q-deformed commutation relations
BoŻejko, Marek; Lytvynov, Eugene; Wysoczański, Janusz
2017-07-01
We consider Fock representations of the Q-deformed commutation relations ∂s∂t†=Q (s ,t ) ∂t†∂s+δ (s ,t ) for s ,t ∈T . Here T :=Rd (or more generally T is a locally compact Polish space), the function Q :T2→C satisfies |Q (s ,t ) |≤1 and Q (s ,t ) =Q (t ,s ) ¯ , and ∫T2h (s ) g (t ) δ (s ,t ) σ (d s ) σ (d t ) :=∫Th (t ) g (t ) σ (d t ) , σ being a fixed reference measure on T. In the case, where |Q (s ,t ) |≡1 , the Q-deformed commutation relations describe a generalized statistics studied by Liguori and Mintchev. These generalized statistics contain anyon statistics as a special case (with T =R2 and a special choice of the function Q). The related Q-deformed Fock space F (H ) over H :=L2(T →C ,σ ) is constructed. An explicit form of the orthogonal projection of H⊗n onto the n-particle space Fn(H ) is derived. A scalar product in Fn(H ) is given by an operator Pn≥0 in H⊗n which is strictly positive on Fn(H ) . We realize the smeared operators ∂t† and ∂t as creation and annihilation operators in F (H ) , respectively. Additional Q-commutation relations are obtained between the creation operators and between the annihilation operators. They are of the form ∂s†∂t†=Q (t ,s ) ∂t†∂s†, ∂s∂t=Q (t ,s ) ∂t∂s, valid for those s ,t ∈T for which |Q(s, t)| = 1.
DEFF Research Database (Denmark)
Zhang, Zhenbo; Tao, N.R.; Mishin, Oleg V.
2015-01-01
dynamic plastic deformation. Different boundary spacings and different stored energy densities for regions belonging to either of the two fibre texture components result in a quite heterogeneous deformation microstructure. Upon annealing, preferential recovery and preferential nucleation...... of recrystallization are found in the 〈111〉- oriented lamellae, which had a higher stored energy density in the as-deformed condition. In the course of recrystallization, the initial duplex fibre texture is replaced by a strong 〈111〉 fibre recrystallization texture....
The dispersion relations of dispersive Alfvén waves in superthermal plasmas
Gaelzer, Rudi; Ziebell, Luiz F.
2014-12-01
The effects of velocity distribution functions (VDFs) that exhibit a power law dependence on the high-energy tail have been the subject of intense research by the space plasma community. Such functions, known as superthermal or kappa distributions, have been found to provide a better fitting to the VDF measured by several spacecraft in the plasma environment of the solar wind. In the literature, the general treatment for waves excited by (bi-)Maxwellian plasmas is well established. However, for kappa distributions, either isotropic or anisotropic, the wave characteristics have been studied mostly for the limiting cases of purely parallel or perpendicular propagation. Contributions for the general case of obliquely propagating waves have been scarcely reported so far. In this work we introduce a mathematical formalism that provides expressions for the dielectric tensor components and subsequent dispersion relations for oblique propagating dispersive Alfvén waves (DAWs) resulting from a kappa VDF. We employ an isotropic distribution, but the methods used here can be easily applied to more general anisotropic distributions, such as the bi-kappa or product-bi-kappa. The effect of the kappa index and thermal corrections on the dispersion relations of DAW is discussed.
Dispersion Relations for Electroweak Observables in Composite Higgs Models
Contino, Roberto
2015-01-01
We derive dispersion relations for the electroweak oblique observables measured at LEP in the context of $SO(5)/SO(4)$ composite Higgs models. It is shown how these relations can be used and must be modified when modeling the spectral functions through a low-energy effective description of the strong dynamics. The dispersion relation for the parameter $\\epsilon_3$ is then used to estimate the contribution from spin-1 resonances at the 1-loop level. Finally, it is shown that the sign of the contribution to the $\\hat S$ parameter from the lowest-lying spin-1 states is not necessarily positive definite, but depends on the energy scale at which the asymptotic behavior of current correlators is attained.
The Use of Dispersion Relations For The Geomagnetic Transfer Functions
Marcuello, A.; Queralt, P.; Ledo, J. J.
The magnetotelluric responses are complex magnitudes, where real and imaginary parts contain the same information on the geoelectrical structure. It seems possible, from very general hypotheses on the geoelectrical models (causality, stability and passivity), to apply the Kramers-Krönig dispersion relations to the magnetotelluric responses (impedance, geomagnetic transfer functions,...). In particular, the applica- bility of these relations to the impedance is a current point of discussion, but there are not many examples of their application to the geomagnetic transfer functions (tipper). The aim of this paper is to study how the relations of dispersion are applied to the real and imaginary part of the geomagnetic transfer functions, and to check its validity. For this reason, we have considered data (or responses) from two- and three-dimensional structures, and for these data, we have taken two situations: 1.- Responses that have been synthetically generated from numerical modelling, that allows us to control the quality of the data. 2.- Responses obtained from fieldwork, that are affected by exper- imental error. Additionally, we have also explored the use of these relations to extrap- olate the geomagnetic transfer functions outside the interval of measured frequencies, in order to obtain constrains on the values of these extrapolated data. The results have shown that the dispersion relations are accomplished for the geomag- netic transfer functions, and they can offer information about how these responses are behaved outside (but near) the range of measured frequencies.
Autogenous Deformation and Change of the Relative Humidity in Silica Fume-Modified Cement Paste
DEFF Research Database (Denmark)
Jensen, Ole mejlhede; Hansen, Per Freiesleben
1996-01-01
Even during sealed curing and at a constant temperature a hardening cement paste will deform and the relative humidity within its pores will lower. This autogenous deformation and autogenous relative humidity change may be so significant that the cement paste cracks if the deformation is restrained....... This article focuses on the influence of silica fume addition on autogenous deformation and autogenous relative humidity change. Continuous measurement of autogenous deformation and autogenous relative humidity change for more than 1 year and 1« years, respectively, was performed. The investigations show...... thatsilica fume addition markedly increases the autogenous shrinkage as well as the autogenous relative humidity change....
Modified dispersion relations, inflation and scale-invariance
Bianco, Stefano; Wilson-Ewing, Edward
2016-01-01
For a certain type of modified dispersion relations, the vacuum quantum state for very short wavelength cosmological perturbations is scale-invariant and it has been suggested that this may be the source of the scale-invariance observed in the temperature anisotropies in the cosmic microwave background. We point out that for this scenario to be possible, it is necessary to red-shift these short wavelength modes to cosmological scales in such a way that the scale-invariance is not lost. This can be done by inflation with a sufficiently large Hubble rate, without any requirement for slow roll. We also show that in the case of slow-roll inflation, modes that start in their vacuum quantum state will become nearly scale-invariant when they exit the Hubble radius for any power law modified dispersion relation.
Dispersion relation and surface gravity of universal horizons
Ding, Chikun
2016-01-01
In Einstein-aether theory, violating Lorentz invariance permits some super-luminal communications, and the universal horizon can trap excitations traveling at arbitrarily high velocities. To better understand the nature of these universal horizons, we use ray tracing method to study their surface gravity in charged Einstein-aether black hole spacetime. Instead of the previous result in Ref. [Phys. Rev. D 89, 064061], our results show that the surface gravity of the universal horizon is dependent on the specific dispersion relation, $\\kappa_{UH}=2(z-1)\\kappa_{uh}/z$, where $z$ denotes the power of the leading term in the superluminal dispersion relation, characterizing different species of particles. And the associated Hawking temperatures also are different with $z$. These findings, which coincide with those in Ref. [arXiv: 1512.01900] derived by the tunneling method, provide a full understanding of black hole thermodynamics in Lorentz-violating theories.
Dispersion relation and surface gravity of universal horizons
Ding, ChiKun; Liu, ChangQing
2017-05-01
In Einstein-aether theory, violating Lorentz invariance permits some super-luminal communications, and the universal horizon can trap excitations traveling at arbitrarily high velocities. To better understand the nature of these universal horizons, we first modify the ray tracing method, and then use it to study their surface gravity in charged Einstein-aether black hole spacetime. Instead of the previous result by Cropp et al., our results show that the surface gravity of the universal horizon is dependent on the specific dispersion relation, K UH = 2( z - 1) K uh/ z, where z denotes the power of the leading term in the superluminal dispersion relation, characterizing different species of particles. And the associated Hawking temperatures also are different with z. These findings, which coincide with those derived by the tunneling method, provide some full understanding of black hole thermodynamics in Lorentz-violating theories.
Representation of Integral Dispersion Relations by Local Forms
Ferreira, Erasmo
2007-01-01
The representation of the usual integral dispersion relations (IDR) of scattering theory through series of derivatives of the amplitudes is discussed, extended, simplified, and confirmed as mathematical identities. Forms of derivative dispersion relations (DDR) valid for the whole energy interval, recently obtained and presented as double infinite series, are simplified through the use of new sum rules of the incomplete $\\Gamma$ functions, being reduced to single summations, where the usual convergence criteria are easily applied. For the forms of the imaginary amplitude used in phenomenology of hadronic scattering, we show that expressions for the DDR can represent, with absolute accuracy, the IDR of scattering theory, as true mathematical identities. Besides the fact that the algebraic manipulation can be easily understood, numerical tests prove the accuracy of these representations up to the maximum available machine precision. As consequence of our analytical and numerical work, it is concluded that the s...
Pionic dispersion relations in presence of weak magnetic field
Adhya, Souvik Priyam; Biswas, Subhrajyoti; Roy, Pradip K
2016-01-01
In this work, dispersion relations of $\\pi^0$ and $\\pi^{\\pm}$ have been studied in vacuum in the limit of weak external magnetic field using a phenomenological pion-nucleon $(\\pi N)$ Lagrangian. For our purpose, we have calculated the results up to one loop order in self energy diagrams with the pseudoscalar $(PS)$ and pseudovector $(PV)$ pion-nucleon interactions. By assuming weak external magnetic field it is seen that the effective mass of pion gets explicit magnetic field dependence and it is modified significantly for the case of PS coupling. However, for the PV coupling, only a modest increase in the effective mass is observed. These modified dispersion relations due to the presence of the external field can have substantial influence in the phenomenological aspect of the mesons both in the context of neutron stars as well as relativistic heavy ion collisions.
Institute of Scientific and Technical Information of China (English)
RUDRAIAH N.; DEVARAJU N.; NG Chiu-On
2011-01-01
Under the effects of electric field and chemical reaction, the problem of dispersion of aerosols in a poorly conducting fluid in a channel is solved analytically using the mixture theory together with a regular perturbation technique.It is shown that the aerosols are dispersed relative to a plane moving with the mean speed of atmospheric fluid as well as the mean speed of agglomeration of aerosol with a relative diffusion coefficient, called the Taylor dispersion coefficient.This coefficient is numerically computed and the results reveal that it increases with an increase in the electric number, but decreases with increasing porous parameter.The physical explanations for the phenomena are given in this article.
Comment on "Dispersion relation for MHD waves in homogeneous plasma"
Chandra, Suresh; Kumthekar, B K; Sharma, Monika
2009-01-01
Pandey & Dwivedi (2007) again tried to claim that the dispersion relation for the given set of equations must be a sixth degree polynomial. Through a series of papers, they are unnecessarily creating confusion. In the present communication, we have shown how Pandey & Dwivedi (2007) are introducing an additional root, which is insignificant. Moreover, five roots of both the polynomials are common and they are sufficient for the discussion of propagation of slow-mode and fast-mode waves.
DEFF Research Database (Denmark)
Zhang, Zhenbo; Tao, N. R.; Mishin, Oleg V.
2016-01-01
, which substantially increases the strength of the material, but decreases its thermal stability. In the as-deformed microstructure, the stored energy density is found to be higher in 〈111〉-oriented regions than in 〈100〉-oriented regions. Recovery during annealing at 715 °C reduces the energy stored...... in the deformed microstructure. This reduction is more pronounced in the 〈111〉-oriented regions. Orientation-dependent recrystallisation takes place in the recovered microstructure, leading to strengthening of the 〈111〉 fibre texture component at the expense of the 〈100〉 fibre texture component....
General characteristics of relative dispersion in the ocean
Corrado, Raffaele; Lacorata, Guglielmo; Palatella, Luigi; Santoleri, Rosalia; Zambianchi, Enrico
2017-04-01
The multi-scale and nonlinear nature of the ocean dynamics dramatically affects the spreading of matter, like pollutants, marine litter, etc., of physical and chemical seawater properties, and the biological connectivity inside and among different basins. Based on the Finite-Scale Lyapunov Exponent analysis of the largest available near-surface Lagrangian data set from the Global Drifter Program, our results show that, despite the large variety of flow features, relative dispersion can ultimately be described by a few parameters common to all ocean sub-basins, at least in terms of order of magnitude. This provides valuable information to undertake Lagrangian dispersion studies by means of models and/or of observational data. Moreover, our results show that the relative dispersion rates measured at submesoscale are significantly higher than for large-scale dynamics. Auxiliary analysis of high resolution GPS-tracked drifter hourly data as well as of the drogued/undrogued status of the buoys is provided in support of our conclusions. A possible application of our study, concerning reverse drifter motion and error growth analysis, is proposed relatively to the case of the missing Malaysia Airlines MH370 aircraft.
Clobert, J.; Danchin, E.; Dhondt, A.A.; Nichols, J.D.
2001-01-01
The ability of species to migrate and disperse is a trait that has interested ecologists for many years. Now that so many species and ecosystems face major environmental threats from habitat fragmentation and global climate change, the ability of species to adapt to these changes by dispersing, migrating, or moving between patches of habitat can be crucial to ensuring their survival. This book provides a timely and wide-ranging overview of the study of dispersal and incorporates much of the latest research. The causes, mechanisms, and consequences of dispersal at the individual, population, species and community levels are considered. The potential of new techniques and models for studying dispersal, drawn from molecular biology and demography, is also explored. Perspectives and insights are offered from the fields of evolution, conservation biology and genetics. Throughout the book, theoretical approaches are combined with empirical data, and care has been taken to include examples from as wide a range of species as possible.
Fast Pairwise Conversion of Supernova Neutrinos: A Dispersion Relation Approach
Izaguirre, Ignacio; Raffelt, Georg; Tamborra, Irene
2017-01-01
Collective pair conversion νeν¯ e↔νxν¯ x by forward scattering, where x =μ or τ , may be generic for supernova neutrino transport. Depending on the local angular intensity of the electron lepton number carried by neutrinos, the conversion rate can be "fast," i.e., of the order of √{2 }GF(nνe-nν¯e)≫Δ matm2/2 E . We present a novel approach to understand these phenomena: a dispersion relation for the frequency and wave number (Ω ,K ) of disturbances in the mean field of νeνx flavor coherence. Runaway solutions occur in "dispersion gaps," i.e., in "forbidden" intervals of Ω and/or K where propagating plane waves do not exist. We stress that the actual solutions also depend on the initial and/or boundary conditions, which need to be further investigated.
Dispersion Relation of Linear Waves in Quantum Magnetoplasmas
Zhu, Jun
2016-07-01
The quantum magnetohydrodynamic (QMHD) model is applied in investigating the propagation of linear waves in quantum magnetoplasmas. Using the QMHD model, the dispersion equation for quantum magnetoplasmas and the dispersion relations of linear waves are deduced. Results show that quantum effects affect the propagation of electron plasma waves and extraordinary waves (X waves). When we select the plasma parameters of the laser-based plasma compression (LBPC) schemes for calculation, the quantum correction cannot be neglected. Meanwhile, the corrections produced by the Fermi degeneracy pressure and Bohm potential are compared under different plasma parameter conditions. supported by National Natural Science Foundation of China (No. 11447125) and the Research Training Program for Undergraduates of Shanxi University of China (Nos. 2014012167, 2015013182)
Dispersion Relation for the Nucleon Electromagnetic Form Factors
Furuichi, Susumu; Watanbe, Keiji
2010-01-01
Elastic electromagnetic form factors of nucleons are investigated both for the time-like and the space-like momentums by using the unsubtracted dispersion relation with QCD constraints. It is shown that the calculated form factors reproduce the experimental data reasonably well; they agree with recent experimental data for the neutron magnetic form factors for the space-like data obtained by the CLAS collaboration and are compatible with the ratio of the electric and magnetic form factors for the time-like momentum obtained by the BABAR collaboration.
Local stability of a gravitating filament: a dispersion relation
Freundlich, Jonathan; Combes, Françoise
2014-01-01
Filamentary structures are ubiquitous in astrophysics and are observed at various scales. On a cosmological scale, matter is usually distributed along filaments, and filaments are also typical features of the interstellar medium. Within a cosmic filament, matter can contract and form galaxies, whereas an interstellar gas filament can clump into a series of bead-like structures which can then turn into stars. To investigate the growth of such instabilities, we derive a local dispersion relation for an idealized self-gravitating filament, and study some of its properties. Our idealized picture consists of an infinite self-gravitating and rotating cylinder with pressure and density related by a polytropic equation of state. We assume no specific density distribution, treat matter as a fluid, and use hydrodynamics to derive the linearized equations that govern the local perturbations. We obtain a dispersion relation for axisymmetric perturbations and study its properties in the (k_R, k_z) phase space, where k_R a...
Wide Dispersion and Diversity of Clonally Related Inhibitory Interneurons.
Harwell, Corey C; Fuentealba, Luis C; Gonzalez-Cerrillo, Adrian; Parker, Phillip R L; Gertz, Caitlyn C; Mazzola, Emanuele; Garcia, Miguel Turrero; Alvarez-Buylla, Arturo; Cepko, Constance L; Kriegstein, Arnold R
2015-09-02
The mammalian neocortex is composed of two major neuronal cell types with distinct origins: excitatory pyramidal neurons and inhibitory interneurons, generated in dorsal and ventral progenitor zones of the embryonic telencephalon, respectively. Thus, inhibitory neurons migrate relatively long distances to reach their destination in the developing forebrain. The role of lineage in the organization and circuitry of interneurons is still not well understood. Utilizing a combination of genetics, retroviral fate mapping, and lineage-specific retroviral barcode labeling, we find that clonally related interneurons can be widely dispersed while unrelated interneurons can be closely clustered. These data suggest that migratory mechanisms related to the clustering of interneurons occur largely independent of their clonal origin.
Dispersion relations in quantum electrodynamics on the noncommutative Minkowski space
Energy Technology Data Exchange (ETDEWEB)
Zahn, J.W.
2006-12-15
We study field theories on the noncommutative Minkowski space with noncommuting time. The focus lies on dispersion relations in quantized interacting models in the Yang-Feldman formalism. In particular, we compute the two-point correlation function of the field strength in noncommutative quantum electrodynamics to second order. At this, we take into account the covariant coordinates that allow the construction of local gauge invariant quantities (observables). It turns out that this does not remove the well-known severe infrared problem, as one might have hoped. Instead, things become worse, since nonlocal divergences appear. We also show that these cancel in a supersymmetric version of the theory if the covariant coordinates are adjusted accordingly. Furthermore, we study the {phi}{sup 3} and the Wess-Zumino model and show that the distortion of the dispersion relations is moderate for parameters typical for the Higgs field. We also discuss the formulation of gauge theories on noncommutative spaces and study classical electrodynamics on the noncommutative Minkowski space using covariant coordinates. In particular, we compute the change of the speed of light due to nonlinear effects in the presence of a background field. Finally, we examine the so-called twist approach to quantum field theory on the noncommutative Minkowski space and point out some conceptual problems of this approach. (orig.)
Relative toxicity of oil dispersants to Mytilus viridis and Macrobrachium idella
Digital Repository Service at National Institute of Oceanography (India)
DeSilva, C.; Row, A.
There was a great variation in the relative toxicity of different oil dispersants. Dispersant IB 2/80 was most toxic and dispersant IB 11/80 was not lethal at the highest concentration tested. The ranking order of the emulsions (oil dispersant...
Structural deformations in liquid crystals with dispersed magnetic nano-colloids
Directory of Open Access Journals (Sweden)
S Shoarinejad
2012-06-01
Full Text Available The stable colloidal dispersions of magnetic nano-particles in nematic liquid crystals are called ferronematics. Their behaviour in magnetic fields depends on various parameters such as anchoring energy, magnetic anisotropy, and shape and volume fraction of the particles. In the present paper, the threshold field is obtained for these colloidal nematics. Then, the influence of magnetic anisotropy, cell thickness, magnetic moment, and volume fraction of the particles are discussed . It is found that due to the influence of some effective parameters, the threshold field changes when compared to pure nematic liquid crystals. The obtained results are consistent with the reported experimental results.
Multi-Particle States in Deformed Special Relativity
Hossenfelder, S
2007-01-01
We investigate the properties of multi-particle states in Deformed Special Relativity (DSR). Starting from the Lagrangian formalism with an energy dependent metric, the conserved Noether current is derived and is found to be additive in the usual way. This quantity had previously been discarded because it was correctly realized that it does no longer obey the DSR transformations. We identify the reason for this mismatch in the fact that DSR depends only on the extensive quantity of total four-momentum instead of the energy-momentum densities as would be appropriate for a field theory. We argue that the reason for the failure of DSR to reproduce the standard transformation behavior in the well established limits is due to the missing sensitivity to the volume inside which energy is accumulated. We show that the soccer-ball problem is absent if one formulates DSR instead for the field densities. As a consequence, estimates for predicted effects have to be corrected by many orders of magnitude. Further, we deriv...
Deformation Behavior of Severely Deformed Al and Related Mechanisms Through Warm Tensile Test
Charkhesht, V.; Kazeminezhad, M.
2017-01-01
Flow stress and ductility behaviors of the annealed and severely deformed Al were investigated at warm deformation temperatures. Constrained groove pressing (CGP) method as a severe plastic deformation process was used. The tensile test was carried out at the temperature range of the 298-573 K and strain rate range of 0.001-0.1 s-1 to present the elevated temperature deformation behavior utilizing hyperbolic sine constitutive equation. The flow stress of the CGPed sample is increased with the number of CGP passes and decreased with temperature. Dynamic recovery and strain softening are found as main restoration mechanisms. Flow stress amounts are not remarkably affected by the strain rate. Values of the elongation are decreased with the number of CGP passes. Values of the calculated strain rate sensitivity are utilized to justify the elongation behavior. Shear bands created by CGP remarkably decrease the fracture elongation values. Temperature interval of 298-473 K cannot remarkably affect the flow stress and ductility. The interval of 473-573 K is chosen as critical temperature interval in which the values of flow stress and elongation are remarkably decreased and increased, respectively. Increasing the temperature up to 573 K causes recrystallization in shear bands. Scanning electron microscope was used to study fracture surface which can truly predict the elongation behavior. With increasing the temperature, the shear decohesion area is gradually replaced with fully dimpled structures. Finally, hot deformation activation energy for CGPed samples was calculated about 85 kJ/mol which is close to the grain boundary diffusion activation energy in pure Al.
Thermal fermionic dispersion relations in a magnetic field
Elmfors, P; Skagerstam, B S; Elmfors, Per; Persson, David; Skagerstam, Bo Sture
1996-01-01
The thermal self-energy of an electron in a static uniform magnetic field B is calculated to first order in the fine structure constant \\alpha and to all orders in eB. We use two methods, one based on the Furry picture and another based on Schwinger's proper-time method. As external states we consider relativistic Landau levels with special emphasis on the lowest Landau level. In the high-temperature limit we derive self-consistent dispersion relations for particle and hole excitations, showing the chiral asymmetry caused by the external field. For weak fields, earlier results on the ground- state energy and the anomalous magnetic moment are discussed and compared with the present analysis. In the strong-field limit the appearance of a field-independent imaginary part of the self-energy, related to Landau damping in the e^{+}e^{-} plasma, is pointed out.
Increased incidence of thoracic wall deformities in related Bengal kittens.
Charlesworth, Timothy M; Sturgess, Christopher P
2012-06-01
Clinical records made during routine vaccinations were compared between populations of domestic shorthair cats and Bengal kittens. An increased incidence (12/244) of thoracic wall deformity was detected amongst the Bengal kittens. Deformities detected were: pectus excavatum (five), unilateral thoracic wall concavity (six) and scoliosis (one). Five-generation pedigrees were analysed for the affected kittens that showed a high degree of common ancestry indicating the likelihood of a familial cause.
Fast Pairwise Conversion of Supernova Neutrinos: A Dispersion Relation Approach.
Izaguirre, Ignacio; Raffelt, Georg; Tamborra, Irene
2017-01-13
Collective pair conversion ν_{e}ν[over ¯]_{e}↔ν_{x}ν[over ¯]_{x} by forward scattering, where x=μ or τ, may be generic for supernova neutrino transport. Depending on the local angular intensity of the electron lepton number carried by neutrinos, the conversion rate can be "fast," i.e., of the order of sqrt[2]G_{F}(n_{ν_{e}}-n_{ν[over ¯]_{e}})≫Δm_{atm}^{2}/2E. We present a novel approach to understand these phenomena: a dispersion relation for the frequency and wave number (Ω,K) of disturbances in the mean field of ν_{e}ν_{x} flavor coherence. Runaway solutions occur in "dispersion gaps," i.e., in "forbidden" intervals of Ω and/or K where propagating plane waves do not exist. We stress that the actual solutions also depend on the initial and/or boundary conditions, which need to be further investigated.
The Relation Between Halo Shape, Velocity Dispersion and Formation Time
Ragone-Figueroa, C; Merchan, M; Gottlober, S; Yepes, G
2010-01-01
We use dark matter haloes identified in the MareNostrum Universe and galaxy groups identified in the Sloan Data Release 7 galaxy catalogue, to study the relation between halo shape and halo dynamics, parametrizing out the mass of the systems. A strong shape-dynamics, independent of mass, correlation is present in the simulation data, which we find it to be due to different halo formation times. Early formation time haloes are, at the present epoch, more spherical and have higher velocity dispersions than late forming-time haloes. The halo shape-dynamics correlation, albeit weaker, survives the projection in 2D (ie., among projected shape and 1-D velocity dispersion). A similar shape-dynamics correlation, independent of mass, is also found in the SDSS DR7 groups of galaxies and in order to investigate its cause we have tested and used, as a proxy of the group formation time, a concentration parameter. We have found, as in the case of the simulated haloes, that less concentrated groups, corresponding to late fo...
Threshold singularities, dispersion relations and fixed-order perturbative calculations
Beneke, Martin
2016-01-01
We show how to correctly treat threshold singularities in fixed-order perturbative calculations of the electron anomalous magnetic moment and hadronic pair production processes such as top pair production. With respect to the former, we demonstrate the equivalence of the "non-perturbative", resummed treatment of the vacuum polarization contribution, whose spectral function exhibits bound state poles, with the fixed-order calculation by identifying a threshold localized term in the four-loop spectral function. In general, we find that a modification of the dispersion relation by threshold subtractions is required to make fixed-order calculations well-defined and provide the subtraction term. We then solve the apparent problem of a divergent convolution of the partonic cross section with the parton luminosity in the computation of the top pair production cross section starting from the fourth-order correction. We find that when the computation is performed in the usual way as an integral of real and virtual cor...
Counterintuitive dispersion violating Kramers-Kronig relations in gain slabs.
Wang, Li-Gang; Wang, Lin; Al-Amri, M; Zhu, Shi-Yao; Zubairy, M Suhail
2014-06-13
We demonstrate the counterintuitive dispersion effect that the peaks (dips) in the gain spectrum correspond to abnormal (normal) dispersion, contrary to the usual Kramers-Kronig point of view. This effect may also lead to two unique features: a broadband abnormal dispersion region and an observable Hartman effect. These results are explained in terms of interference and boundary effects. Finally, two experiments are proposed for the potential experimental verification.
Age velocity dispersion relations and heating histories in disc galaxies
Aumer, Michael; Schönrich, Ralph
2016-01-01
We analyse the heating of stellar discs by non axisymmetric structures and giant molecular clouds (GMCs) in N-body simulations of growing disc galaxies. The analysis resolves long-standing discrepancies between models and data by demonstrating the importance of distinguishing between measured age-velocity dispersion relations (AVRs) and the heating histories of the stars that make up the AVR. We fit both AVRs and heating histories with formulae proportional to t^beta and determine the exponents beta_R and beta_z derived from in-plane and vertical AVRs and ~beta_R and ~beta_z from heating histories. Values of beta_z are in almost all simulations larger than values of ~beta_z, whereas values of beta_R are similar to or mildly larger than values of ~beta_R. Moreover, values of beta_z (~beta_z) are generally larger than values of beta_R (~beta_R). The dominant cause of these relations is the decline over the life of the disc in importance of GMCs as heating agents relative to spiral structure and the bar. We exam...
Analysis of Orientation Relations Between Deformed Grains and Recrystallization Nuclei
DEFF Research Database (Denmark)
West, Stine S.; Winther, Grethe; Juul Jensen, Dorte
2011-01-01
Nucleation in 30 pct rolled high-purity aluminum samples was investigated by the electron backscattering pattern method before and after annealing. A total of 29 nuclei including two twins were observed, and approximately one third of these nuclei had orientations not detected in the deformed sta...
Stress–strain relations for hydrogels under multiaxial deformation
DEFF Research Database (Denmark)
Drozdov, Aleksey; Christiansen, Jesper de Claville
2013-01-01
Constitutive equations are derived for the elastic response of swollen elastomers and hydrogels under an arbitrary deformation with finite strains. An expression is developed for the free energy density of a polymer network based on the Flory concept of flexible chains with constrained junctions...
Relating seismic swarms and deformation in Long Valley Caldera, California
Montgomery-Brown, E. K.; Ellsworth, W. L.; Hill, D. P.; Shelly, D. R.; Langbein, J. O.; Lisowski, M.; Llenos, A. L.
2013-12-01
Earthquake swarm activity in the South Moat Seismic Zone (SMSZ) in Long Valley caldera began increasing following the onset of slow inflation of the resurgent dome in 2011. From 1980 through 1999 the caldera produced recurring earthquake swarms in the SMSZ accompanied by an 80-cm uplift of the resurgent dome. Since 2000, the caldera has been quieter than from 1980 to 1999, but it experienced a gradual 7-cm uplift episode in 2002-2003 and currently the caldera has been gradually uplifting since 2011 at less than half of the peak uplift velocity observed in the late 1990's. Two of the recent swarms in October/November of 2012 and March 2013 have been accompanied by small deformation transients during which caldera uplift paused for about a week despite otherwise steady inflation. To better understand this recent activity, we cross correlate seismic velocity waveforms from individual events recorded by the Long Valley seismic network to identify similar clusters (families) of earthquakes and analyze their temporal recurrence. Then, we use representative waveforms from each family as templates to search the continuous waveforms from the deep borehole seismometers in the Long Valley Exploratory Well (MDH1) for repeating, yet smaller, earthquakes. MDH1 consists of two three-component instruments, located 2592 m and 2263 m below ground level, that provide 6 channels with very low background noise relative to surface seismometers. The cross correlations identify about 25 times more earthquakes with most magnitudes ranging from -1 to +0.5, determined from an empirical relationship between catalog magnitude and observed amplitude on MDH1. We apply an ETAS model to the augmented catalog to detect subtle changes in background earthquake rates that might suggest a change in stressing rate. For comparison with the change in seismicity rates, a geodetically determined stress change is estimated from a simple model of the continuous GPS data. We model the uplift from 2011 to
EARTHQUAKE-INDUCED DEFORMATION STRUCTURES AND RELATED TO EARTHQUAKE MAGNITUDES
Directory of Open Access Journals (Sweden)
Savaş TOPAL
2003-02-01
Full Text Available Earthquake-induced deformation structures which are called seismites may helpful to clasify the paleoseismic history of a location and to estimate the magnitudes of the potention earthquakes in the future. In this paper, seismites were investigated according to the types formed in deep and shallow lake sediments. Seismites are observed forms of sand dikes, introduced and fractured gravels and pillow structures in shallow lakes and pseudonodules, mushroom-like silts protruding laminites, mixed layers, disturbed varved lamination and loop bedding in deep lake sediments. Earthquake-induced deformation structures, by benefiting from previous studies, were ordered according to their formations and earthquake magnitudes. In this order, the lowest eartquake's record is loop bedding and the highest one is introduced and fractured gravels in lacustrine deposits.
Threshold singularities, dispersion relations and fixed-order perturbative calculations
Energy Technology Data Exchange (ETDEWEB)
Beneke, M.; Ruiz-Femenía, P. [Physik Department T31, Technische Universität München,James-Franck-Straße, D-85748 Garching (Germany)
2016-08-24
We show how to correctly treat threshold singularities in fixed-order perturbative calculations of the electron anomalous magnetic moment and hadronic pair production processes such as top pair production. With respect to the former, we demonstrate the equivalence of the “non-perturbative”, resummed treatment of the vacuum polarization contribution, whose spectral function exhibits bound state poles, with the fixed-order calculation by identifying a threshold localized term in the four-loop spectral function. In general, we find that a modification of the dispersion relation by threshold subtractions is required to make fixed-order calculations well-defined and provide the subtraction term. We then solve the apparent problem of a divergent convolution of the partonic cross section with the parton luminosity in the computation of the top pair production cross section starting from the fourth-order correction. We find that when the computation is performed in the usual way as an integral of real and virtual corrections over phase space at a given order in the expansion in the strong coupling, an additional contribution has to be added at N3LO.
On integrable deformations of superstring sigma models related to AdSn×Sn supercosets
Directory of Open Access Journals (Sweden)
B. Hoare
2015-08-01
Full Text Available We consider two integrable deformations of 2d sigma models on supercosets associated with AdSn×Sn. The first, the “η-deformation” (based on the Yang–Baxter sigma model, is a one-parameter generalization of the standard superstring action on AdSn×Sn, while the second, the “λ-deformation” (based on the deformed gauged WZW model, is a generalization of the non-abelian T-dual of the AdSn×Sn superstring. We show that the η-deformed model may be obtained from the λ-deformed one by a special scaling limit and analytic continuation in coordinates combined with a particular identification of the parameters of the two models. The relation between the couplings and deformation parameters is consistent with the interpretation of the first model as a real quantum deformation and the second as a root of unity quantum deformation. For the AdS2×S2 case we then explore the effect of this limit on the supergravity background associated with the λ-deformed model. We also suggest that the two models may form a dual Poisson–Lie pair and provide direct evidence for this in the case of the integrable deformations of the coset associated with S2.
Deformation of superplastic alloys at relatively low strain rates
Energy Technology Data Exchange (ETDEWEB)
Grivas, D.
1978-02-01
The superplastic and sub-superplastic creep properties of Pb-Sn eutectic and Al-Zn eutectoid alloys were studied. Various thermomechanical treatments we tested to check the possibilities of whether the subsuperplastic deformation mechanism is affected by these treatments. All thermomechanical histories were found to reveal the same stress exponent, which is believed to be indicative of the predominant mechanism. The mechanical data in the low stress region lead us to suggest that dislocation glide is the predominant mechanism in this region. At higher stresses extensive grain boundary sliding takes place and the dislocation movement is directed to relieve the stress concentration developed by the grain movement.
Noncommutative Poisson brackets on Loday algebras and related deformation quantization
UCHINO, Kyousuke
2010-01-01
We introduce a new type of algebra which is called a Loday-Poisson algebra. The class of the Loday-Poisson algebras forms a special subclass of Aguiar's dual-prePoisson algebas (\\cite{A}). We will prove that there exists a unique Loday-Poisson algebra over a Loday algebra, like the Lie-Poisson algebra over a Lie algebra. Thus, Loday-Poisson algebras are regarded as noncommutative analogues of Lie-Poisson algebras. We will show that the polinomial Loday-Poisson algebra is deformation quantizable and that the associated quantum algebra is Loday's associative dialgebra.
Once and twice subtracted dispersion relations in the analysis of pi pi amplitudes
Kaminski, R; Peláez, J R; Ynduráin, F J
2009-01-01
Once and twice subtracted crossing symmetric dispersion relations applied to $\\pi\\pi \\to \\pi\\pi$ scattering data are analyzed and compared. Both sets of dispersion relations can be used to test the $\\pi\\pi$ amplitudes in low partial waves up to about 1 GeV. We show how once subtracted dispersion relations can provide stronger constraints for $\\pi\\pi$ amplitudes than twice subtracted ones in the 400 to 1100 MeV range, given the same experimental input.
Lobo, Iarley P; Nettel, Francisco
2016-01-01
In recent years, Planck-scale modifications to particles' dispersion relation have been deeply studied for the possibility to formulate some phenomenology of Planckian effects in astrophysical and cosmological frameworks. There are some indications [arXiv:gr-qc/0611024] that Finsler geometry can provide some generalization of Riemannian geometry which may allow to account for non-trivial (Planckian) structure of relativistic particles' configuration space. We investigate the possibility to formalize Planck-scale deformations to relativistic models in curved spacetime, within the framework of Finsler geometry. We take into account the general strategy of analysis of modifications of dispersion relations in curved spacetimes proposed in [arXiv:1507.02056], generalizing to the de Sitter case the results obtained in [arXiv:1407.8143], for deformed relativistic particle kinematics in flat spacetime using Finsler formalism.
1982-11-01
IN FRESH AND SEAWATER(I) (3)Product Mean Minimum Dispersant-to-Oil Ratio Name on Venezuelan Lago Medio Crude Oil (4) 0C in Fresh Water in Salt Water...higher terminal velocity, adding to the mixing energy. Orienting the nozzles aft can be expected to reduce the relative velocity of the drops, and result
Institute of Scientific and Technical Information of China (English)
BAO Lin; HU Jin-song; YU Yong-liang; CHENG Peng; XU Bo-qing; TONG Bing-gang
2006-01-01
Flexible insect wings deform passively under the periodic loading during flapping flight. The wing flexibility is considered as one of the specific mechanisms on improving insect flight performance. The constitutive relation of the insect wing material plays a key role on the wing deformation, but has not been clearly understood yet. A viscoelastic constitutive relation model was established based on the stress relaxation experiment of a dragonfly wing (in vitro). This model was examined by the finite clement analysis of the dynamic deformation response for a model insect wing under the action of the periodical inertial force in flapping. It is revealed that the viscoelastic constitutive relation is rational to characterize the biomaterial property of insect wings in contrast to the elastic one. The amplitude and form of the passive viscoelastic deformation of the wing is evidently dependent on the viscous parameters in the constitutive relation.
Three-particle physics and dispersion relation theory
Anisovich, A V; Matveev, M A; Nikonov, V A; Nyiri, J; Sarantsev, A V
2013-01-01
The necessity of describing three-nucleon and three-quark systems have led to a constant interest in the problem of three particles. The question of including relativistic effects appeared together with the consideration of the decay amplitude in the framework of the dispersion technique. The relativistic dispersion description of amplitudes always takes into account processes connected with the investigated reaction by the unitarity condition or by virtual transitions; in the case of three-particle processes they are, as a rule, those where other many-particle states and resonances are produced. The description of these interconnected reactions and ways of handling them is the main subject of the book.
Energy Technology Data Exchange (ETDEWEB)
Yang Xuefeng; Cui Jian; Zhang Yuan [School of Mathematical Sciences, Dalian University of Technology, Dalian 116024 (China); Liu Yue [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)
2012-07-15
The dispersion relations of the externally and thermally (naturally) excited dust lattice modes (both longitudinal and transverse) in two-dimensional Debye-Yukawa complex plasma crystals are investigated. The dispersion relations are calculated numerically by taking the neutral gas damping effects into account and the numerical results are in agreement with the experimental data given by Nunomura et al.[Phys. Rev. E 65, 066402 (2002)]. It is found that for the mode excited by an external disturbance with a real frequency, the dispersion properties are changed at a critical frequency near where the group velocity of the mode goes to zero. Therefore, the high frequency branch with negative dispersion cannot be reached. In contrast, for the thermally excited mode, the dispersion curve can extend all the way to the negative dispersion region, while a 'cut-off' wave number exists at the long wavelength end of the dispersion in the transverse mode.
Skewness of cloud droplet spectrum and an improved estimation for its relative dispersion
Liu, Yu; Lu, Chunsong; Li, Weiliang
2017-02-01
The relative dispersion of the cloud droplet spectrum is a very important parameter in describing and modeling cloud microphysical processes. Based on the definition of skewness as well as theoretical and data analyses, a linear fitting relationship ( α = 2.91 ɛ-0.59) between skewness ( α) and relative dispersion ( ɛ) is established and a new method is developed to estimate the relative dispersion of the cloud droplet spectrum. The new method does not depend on any assumption of a particular distribution for the cloud droplet spectrum and has broader applicability than the previous methods. Comparisons of the three methods for the relative dispersion with the observed data supported the following conclusions. (1) The skewness of the cloud droplet spectrum is asymmetrically distributed. An assumption of zero skewness in quantifying the relative dispersion inevitably results in relatively large deviations from the observations. Errors of the estimated relative dispersion due to the omission of the skewness term are not solely related to the skewness, but rather to the product of the skewness and relative dispersion. (2) The use of the assumption that the cloud droplet spectrum takes a gamma distribution is similar to the assumption that the skewness is twice the relative dispersion. This leads to a better accuracy in estimating the relative dispersion than that with zero skewness assumption. (3) Comparisons with observations show that the new method is more accurate than the one under gamma distribution assumption and is the best among all the three methods. (4) It is believed that finding a better correlation between the skewness and the relative dispersion would further reduce the deviations for the estimated relative dispersion.
Dispersion relation for hadronic light-by-light scattering
Directory of Open Access Journals (Sweden)
Procura Massimiliano
2016-01-01
Our dispersive approach defines unambiguously the pion-pole and the pion-box contribution to the HLbL tensor. Using Mandelstam’s double-spectral representation, we have proven that the pion-box contribution coincides exactly with the one-loop scalar QED amplitude, multiplied by the appropriate pion vector form factors.
Comparison of Forward Dispersion Relations with Experiments around 10 GeV
DEFF Research Database (Denmark)
Lautrup, B.; Møller-Nielsen, Peter; Olesen, P.
1965-01-01
Using the recent experimental data on the real part of the forward π±-p amplitude around 10 GeV, we have carried out a comparison of forward dispersion relations with experiments in the high-energy region. In this work we propose a new method for testing forward dispersion relations which involves...... no assumptions whatsoever about the unknown cross sections above 20 GeV. On account of the large systematic errors in the measured real parts, no definite conclusion can be drawn as to the validity of forward dispersion relations. In estimating the standard deviations in the dispersion integrals, a Monte Carlo...... method has been used....
Dispersion relations of the acoustic modes in divalent liquid metals
Directory of Open Access Journals (Sweden)
Inui Masanori
2017-01-01
Full Text Available Collective dynamics in liquid Ca and liquid Cd was studied by inelastic x-ray scattering (IXS. Using our experimental technique to prepare proper sample cells and high performance of an IXS beamline (BL35XU at SPring-8 in Japan, the dynamic structure factor with reasonable statistics was obtained for these divalent liquid metals. For both liquids, the dynamic structure factor at low Q exhibits a central peak with a shoulder or small hump clearly visible on each side, and the inelastic excitation energy determined using the model function composed of Lorentzian and the damped harmonic oscillator function disperses with increasing Q. The dispersion curves of these liquids were compared with that of the longitudinal acoustic phonon in each crystalline phase. From these results, clear difference in the interatomic interaction be- tween liquid Ca and liquid Cd was inferred.
Lukovich, Jennifer V.; Geiger, Cathleen A.; Barber, David G.
2017-07-01
A framework is developed to assess the directional changes in sea ice drift paths and associated deformation processes in response to atmospheric forcing. The framework is based on Lagrangian statistical analyses leveraging particle dispersion theory which tells us whether ice drift is in a subdiffusive, diffusive, ballistic, or superdiffusive dynamical regime using single-particle (absolute) dispersion statistics. In terms of sea ice deformation, the framework uses two- and three-particle dispersion to characterize along- and across-shear transport as well as differential kinematic parameters. The approach is tested with GPS beacons deployed in triplets on sea ice in the southern Beaufort Sea at varying distances from the coastline in fall of 2009 with eight individual events characterized. One transition in particular follows the sea level pressure (SLP) high on 8 October in 2009 while the sea ice drift was in a superdiffusive dynamic regime. In this case, the dispersion scaling exponent (which is a slope between single-particle absolute dispersion of sea ice drift and elapsed time) changed from superdiffusive (α ˜ 3) to ballistic (α ˜ 2) as the SLP was rounding its maximum pressure value. Following this shift between regimes, there was a loss in synchronicity between sea ice drift and atmospheric motion patterns. While this is only one case study, the outcomes suggest similar studies be conducted on more buoy arrays to test momentum transfer linkages between storms and sea ice responses as a function of dispersion regime states using scaling exponents. The tools and framework developed in this study provide a unique characterization technique to evaluate these states with respect to sea ice processes in general. Application of these techniques can aid ice hazard assessments and weather forecasting in support of marine transportation and indigenous use of near-shore Arctic areas.
DISPERSION RELATION OF A MAGNETIZED PLASMA-FILLED BACKWARD WAVE OSCILLATOR
Institute of Scientific and Technical Information of China (English)
GAO HONG; LIU SHENG-GANG
2000-01-01
A linear theory and a more general dispersion relation of electromagnetic radiation from a magnetized plasma-filled backward wave oscillator with sinusoidally corrugated slow-wave structure driven by a solid intense relativistic electron beam have been given. The comparisons show good agreement with the previous works when B0 → ∞ and ωb = 0 from this dispersion relation.
Fukui, M.; So, V. C.-Y.; Stegeman, G. I.
1980-07-01
The recent experiments of DeMartini, Colocci, Kohn, and Shen [Phys. Rev. Lett. 38, 1223 (1977)] on the nonlinear generation of C1- (n=1 in the series) surface exciton polaritons in spatially dispersive ZnO are analyzed. It is shown for a prism-air-sample geometry that the air-gap thickness plays an important role in determining the polariton attenuation, and to a lesser degree the polariton energy. Reasonably good agreement with the experimental dispersion relations of DeMartini and co-workers is obtained by including spatial dispersion via the additional boundary condition (ABC) ∂P→ex/∂z=0 for the excitonic polarization P→ex at the surface: The ABC P→ex=0 does not yield a good fit. The theory of the nonlinear generation of surface exciton polaritons in isotropic, spatially dispersive media is developed and applied to angle- and frequency-scanning experimental geometries. Numerical estimates of both the power radiated out via the prism (in the absence of surface roughness) and the line shape were also found to be in reasonable agreement with experiment for the ABC ∂P→ex/∂x=0, but not for P→ex=0.
Tsou, Ching-Ying; Chigira, Masahiro; Matsushi, Yuki; Chen, Su-Chin
2013-04-01
The Central Range of Taiwan is an example of a tectonically active orogen. The topography of a mountainous catchment of the Dahan River in northern side of the Central Range exhibits V-shaped inner valleys where landsliding is the dominant process of hillslope erosion and bedrock rivers are incising into the landscape. We take two approaches including (i) the study of present day morphostructural features of gravitationally deformed slopes and (ii) the study of the relationship between the gravitational slope deformation and fluvial incision to research the linkage of gravitational slope deformations, catastrophic landslides, and landscape evolution for the prediction of potential sites of future landslides. Mapped deep-seated gravitational slope deformations and scars of rainfall-induced rock/debris avalanches imply that their distributions are closely related to three series of convex slope breaks relating to the rejuvenation of topography by a three-phase fluvial incision leaded by three series of knickpoints migration. Many shallow rock/debris avalanches have occurred below the lowest slope break. By contrast, majority of gravitational slope deformations have occurred at the margins of the highest slope break around the paleosurface remnants, suggesting that the rejuvenation caused debuttressing of hillslopes and subsequent stress-release led to large scale slope destabilization, resulting in gravitational slope deformations. Catastrophic landslides in many locations deem to be preceded by gravitational slope deformation of rocks with adverse geological structures, many of which are buckling of alternating beds of sandstone and mudstone, and toppling of argillite and slate. The gravitationally deformed slopes change the topography and remain for a long time, and commonly accompany with some other types of mass movements (e.g. debris flows, rock/debris avalanches, and rockfalls). The results suggest that landslides are strongly controlled by geomorphology and
The complex dispersion relation of surface plasmon polaritons at gold/para-hexaphenylene interfaces
DEFF Research Database (Denmark)
Lemke, Christoph; Leißner, Till; Klick, Alwin;
2014-01-01
Two-photon photoemission electron microscopy (2P-PEEM) is used to measure the real and imaginary part of the dispersion relation of surface plasmon polaritons at different interface systems. A comparison of calculated and measured dispersion data for a gold/vacuum interface demonstrates the capab......Two-photon photoemission electron microscopy (2P-PEEM) is used to measure the real and imaginary part of the dispersion relation of surface plasmon polaritons at different interface systems. A comparison of calculated and measured dispersion data for a gold/vacuum interface demonstrates...... the capability of the presented experimental approach. A systematic 2P-PEEM study on the dispersion relation of dielectric-loaded gold surfaces shows how effective the propagation of surface plasmon polaritons at a gold/para-hexaphenylene interface can be tuned by adjustment of the dielectric film thickness...
Time-dependent q-deformed bi-coherent states for generalized uncertainty relations
Gouba, Laure
2015-07-01
We consider the time-dependent bi-coherent states that are essentially the Gazeau-Klauder coherent states for the two dimensional noncommutative harmonic oscillator. Starting from some q-deformations of the oscillator algebra for which the entire deformed Fock space can be constructed explicitly, we define the q-deformed bi-coherent states. We verify the generalized Heisenberg's uncertainty relations projected onto these states. For the initial value in time, the states are shown to satisfy a generalized version of Heisenberg's uncertainty relations. For the initial value in time and for the parameter of noncommutativity θ = 0, the inequalities are saturated for the simultaneous measurement of the position-momentum observables. When the time evolves, the uncertainty products are different from their values at the initial time and do not always respect the generalized uncertainty relations.
On a time-domain representation of the Kramers-Kronig dispersion relations
Waters; Hughes; Brandenburger; Miller
2000-11-01
The development of Kramers-Kronig dispersion relations is typically carried out in the frequency domain. An alternative approach known as the time-causal theory develops dispersion relations for media with attenuation obeying a frequency power law through analysis in the time domain [T. L. Szabo, J. Acoust. Soc. Am. 96, 491-500 (1994)]. Although both approaches predict identical dispersion relations, it is perceived that these two approaches are distinct from each other. It is shown, however, that the time-causal theory is in essence a time-domain formulation of the Kramers-Kronig dispersion relations for the special case of media with attenuation obeying a frequency power law. Additionally, it is shown that time-domain representations of the Kramers-Kronig dispersion relations are available for a broader class of media than simply those with power law attenuation. The time-causal theory and the Kramers-Kronig dispersion relations can be viewed as two complementary, yet equivalent, approaches to the study of dispersion.
Moro, M.; Saroli, M.; Lancia, M.; Albano, M.; Lo Sardo, L.; Stramondo, S.
2015-12-01
Modern geomorphological investigations focused on the definition of major factors conditioning the landscape evolution. The interaction of some of these factors as the litho-structural setting, the local relief, the tectonic activity, the climatic conditions and the seismicity plays a key-role in determining large scale slope instability phenomena which display the general morphological features of deep seated gravitational deformations (DSGD). The present work aims to detect the large scale gravitational deformation and relations with the active tectonics affecting the Abruzzo Region and to provide a description of the morphologic features of the deformations by means of aerial photograph interpretation, geological/geomorphological field surveys and DInSAR data. The investigated areas are morphologically characterized by significant elevation changes due to the presence of high mountain peaks, separated from surrounding depressed areas by steep escarpments, frequently represented by active faults. Consequently, relief energy favours the development of gravity-driven deformations. These deformations seem to be superimposed on and influenced by the inherited structural and tectonic pattern, related to the sin- and post-thrusting evolution. The morphological evidences of these phenomena, are represented by landslides, sackungen or rock-flows, lateral spreads and block slides. DInSAR analysis measured deformation of the large scale gravitative phenomena previously identified through aerial-photo analysis. DSGD may evolve in rapid, catastrophic mass movements and this paroxistic evolution of the deformations may be triggered by high magnitude seismic events. These assumptions point out the great importance of mapping in detail large scale slope instability phenomena in relation to the active faults, in a perspective of land-use planning such as the Abruzzo Region characterized by a high magnitude historical seismicity.
New dispersion relations in the description of $\\pi\\pi$ scattering amplitudes
Kaminski, R; Grynkiewicz, P; Peláez, J R; Ynduráin, F J
2009-01-01
We present a set of once subtracted dispersion relations which implement crossing symmetry conditions for the $\\pi\\pi$ scattering amplitudes below 1 GeV. We compare and discuss the results obtained for the once and twice subtracted dispersion relations, known as Roy's equations, for three $\\pi\\pi$ partial JI waves, S0, P and S2. We also show that once subtracted dispersion relations provide a stringent test of crossing and analyticity for $\\pi\\pi$ partial wave amplitudes, remarkably precise in the 400 to 1.1 GeV region, where the resulting uncertainties are significantly smaller than those coming from standard Roy's equations, given the same input.
A new dispersion-relation preserving method for integrating the classical Boussinesq equation
Jang, T. S.
2017-02-01
In this paper, a dispersion-relation preserving method is proposed for nonlinear dispersive waves, starting from the oldest weakly nonlinear dispersive wave mathematical model in shallow water waves, i.e., the classical Boussinesq equation. It is a semi-analytic procedure, however, which preserves, as a distinctive feature, the dispersion-relation imbedded in the model equation without adding (unwelcome) numerical effects, i.e., the proposed method has the same dispersion-relation as the original classical Boussinesq equation. This remarkable (dispersion-relation) preserving property is proved mathematically for small wave motion in present study. The property is also numerically examined by observing both the local wave number and the local frequency of a slowly varying water-wave group. The dispersion-relation preserving method proposed here is powerful as well for observing nonlinear wave phenomena such as solitary waves and their collision. In fact, the main features of nonlinear wave characteristics are clearly seen through not only a single propagating solitary wave but counter-propagating (head-on) solitary wave collisions. They are compared with known (exact) nonlinear solutions, the results of which represent a major improvement over existing solution formulations in the literature.
On the relative contributions of wind vs. animals to seed dispersal of four Sierra Nevada pines.
Vander Wall, Stephen B
2008-07-01
Selective pressures that influence the form of seed dispersal syndromes are poorly understood. Morphology of plant propagules is often used to infer the means of dispersal, but morphology can be misleading. Several species of pines, for example, have winged seeds adapted for wind dispersal but owe much of their establishment to scatter-hoarding animals. Here the relative importance of wind vs. animal dispersal is assessed for four species of pines of the eastern Sierra Nevada that have winged seeds but differed in seed size: lodgepole pine (Pinus contorta murrayana, 8 mg); ponderosa pine (Pinus ponderosa ponderosa, 56 mg); Jeffrey pine (Pinus jeffreyi, 160 mg); and sugar pine (Pinus lambertiana, 231 mg). Pre-dispersal seed mortality eliminated much of the ponderosa pine seed crop (66%), but had much less effect on Jeffrey pine (32% of seeds destroyed), lodgepole pine (29%), and sugar pine (7%). When cones opened most filled seeds were dispersed by wind. Animals removed > 99% of wind-dispersed Jeffrey and sugar pine seeds from the ground within 60 days, but animals gathered only 93% of lodgepole pine seeds and 38% of ponderosa pine seeds during the same period. Animals gathered and scatter hoarded radioactively labeled ponderosa, Jeffrey, and sugar pine seeds, making a total of 2103 caches over three years of study. Only three lodgepole pine caches were found. Caches typically contained 1-4 seeds buried 5-20 mm deep, depths suitable for seedling emergence. Although Jeffrey and sugar pine seeds are initially wind dispersed, nearly all seedlings arise from animal caches. Lodgepole pine is almost exclusively wind dispersed, with animals acting as seed predators. Animals treated ponderosa pine in an intermediate fashion. Two-phased dispersal of large, winged pine seeds appears adaptive; initial wind dispersal helps to minimize pre-dispersal seed mortality whereas scatter hoarding by animals places seeds in sites with a higher probability of seedling establishment.
Fracture statistics of torsion and dispersion relations in round bars
Directory of Open Access Journals (Sweden)
Díaz, G.
1990-09-01
Full Text Available This paper has adopted a theoretical viewpoint for studying Fracture Statistics in round bars subjected to torsion, and for determining the cumulative probabilities of fracture using Weibull's specific-risk function for materials that exhibit volume and surface brittleness. The use of the defined-functions method has allowed to get the specific-risk-of-fracture function and, in addition, to carry out a separation between volume part and surface part concerning materials presenting both brittlenesses at the same time. Dispersion of the parameters are determined resorting to Fisher's information matrix.
Se estudió desde un punto de vista teórico la estadística de fractura de barras de sección circular sometidas a torsión y se determinó las probabilidades acumulativas de fractura usando la función riesgo específico de Weibull para materiales con fragilidades volumétrica y superficial. Mediante el método de las funciones definidas se obtuvo la función riesgo específico de fractura, además se separó la parte volumétrica de la parte superficial para materiales que poseen ambas fragilidades. La dispersión de los parámetros se determinó con la matriz de información de Fisher.
Jiang, Shi-xiao W.; Lu, Hai-hao; Zhou, Douglas; Cai, David
2014-09-01
We study the nonlinear dispersive characteristics in β-Fermi-Pasta-Ulam (FPU) chains in both thermal equilibrium and nonequilibrium steady state. By applying a multiple scale analysis to the FPU chain, we analyze the contribution of the trivial and nontrivial resonance to the renormalization of the dispersion relation. Our results show that the contribution of the nontrivial resonance remains significant to the renormalization, in particular, in strongly nonlinear regimes. We contrast our results with the dispersion relations obtained from the Zwanzig-Mori formalism and random phase approximation to further illustrate the role of resonances. Surprisingly, these theoretical dispersion relations can be generalized to describe dispersive characteristics well at the nonequilibrium steady state of the FPU chain with driving-damping in real space. Through numerical simulation, we confirm that the theoretical renormalized dispersion relations are valid for a wide range of nonlinearities in thermal equilibrium as well as in nonequilibrium steady state. We further show that the dispersive characteristics persist in nonequilibrium steady state driven-damped in Fourier space.
Jiang, Shi-xiao W; Lu, Hai-hao; Zhou, Douglas; Cai, David
2014-09-01
We study the nonlinear dispersive characteristics in β-Fermi-Pasta-Ulam (FPU) chains in both thermal equilibrium and nonequilibrium steady state. By applying a multiple scale analysis to the FPU chain, we analyze the contribution of the trivial and nontrivial resonance to the renormalization of the dispersion relation. Our results show that the contribution of the nontrivial resonance remains significant to the renormalization, in particular, in strongly nonlinear regimes. We contrast our results with the dispersion relations obtained from the Zwanzig-Mori formalism and random phase approximation to further illustrate the role of resonances. Surprisingly, these theoretical dispersion relations can be generalized to describe dispersive characteristics well at the nonequilibrium steady state of the FPU chain with driving-damping in real space. Through numerical simulation, we confirm that the theoretical renormalized dispersion relations are valid for a wide range of nonlinearities in thermal equilibrium as well as in nonequilibrium steady state. We further show that the dispersive characteristics persist in nonequilibrium steady state driven-damped in Fourier space.
A linear dispersion relation for the hybrid kinetic-ion/fluid-electron model of plasma physics
Told, Daniel; Astfalk, Patrick; Jenko, Frank
2016-01-01
A dispersion relation for a commonly used hybrid model of plasma physics is developed, which combines fully kinetic ions and a massless-electron fluid description. Although this model and variations of it have been used to describe plasma phenomena for about 40 years, to date there exists no general dispersion relation to describe the linear wave physics contained in the model. Previous efforts along these lines are extended here to retain arbitrary wave propagation angles, temperature anisotropy effects, as well as additional terms in the generalized Ohm's law which determines the electric field. A numerical solver for the dispersion relation is developed, and linear wave physics is benchmarked against solutions of a full Vlasov-Maxwell dispersion relation solver. This work opens the door to a more accurate interpretation of existing and future wave and turbulence simulations using this type of hybrid model.
Precise analysis of pion-pion scattering data from Roy equations and forward dispersion relations
Peláez, J R; Kaminski, R; Ynduráin, F J
2008-01-01
We review our recent analysis of pion-pion scattering data in terms of Roy equations and Forward Dispersion Relations, and present some preliminary results in terms of a new set of once-subtracted coupled equations for partial waves. The first analysis consists of independent fits to the different pion-pion channels that satisfies rather well the dispersive representation. In the second analysis we constrain the fit with the dispersion relations. The latter provides a very precise and model independent description of data using just analyticity, causality and crossing.
Integral and derivative dispersion relations for pp and $\\overline{p}p$ amplitudes
Alkin, A
2010-01-01
The methods of integral dispersion relations (IDR) and derivative dispersion relations (DDR) are applied for analysis of the data on pp and ¯pp total cross sections and ratios of real to imaginary part of elastic forward scattering amplitude. The models of pomeron behaving as triple, double and simple pole (with intercept larger than one) in the angular momentum plane are considered. Predictions of the models are given for the TOTEM measurements at 7 and 14 TeV.
Nacir, Diana López
2009-01-01
We review our recent results on the renormalization procedure for a free quantum scalar field with modified dispersion relations in curved spacetimes. For dispersion relations containing up to $2s$ powers of the spatial momentum, the subtraction necessary to renormalize $$ and $$ depends on $s$. We first describe our previous analysis for spatially flat Friedman-Robertson-Walker and Bianchi type I metrics. Then we present a new power counting analysis for general background metrics in the weak field approximation.
Riehl, Christina; Stern, Caitlin A
2015-12-01
Cooperative breeding in birds typically occurs when offspring - usually males - delay dispersal from their natal group, remaining with the family to help rear younger kin. Sex-biased dispersal is thought to have evolved in order to reduce the risk of inbreeding, resulting in low relatedness between mates and the loss of indirect fitness benefits for the dispersing sex. In this review, we discuss several recent studies showing that dispersal patterns are more variable than previously thought, often leading to complex genetic structure within cooperative avian societies. These empirical findings accord with recent theoretical models suggesting that sex- biased dispersal is neither necessary, nor always sufficient, to prevent inbreeding. The ability to recognize relatives, primarily by learning individual or group-specific vocalizations, may play a more important role in incest avoidance than currently appreciated.
DEFF Research Database (Denmark)
Jensen, Ole Mejlhede; Hansen, Per Freiesleben
1999-01-01
This paper deals with autogenous deformation and autogenous relative humidity change (RH change) in hardening cement paste. Theoretical considerations and experimental data are presented, which elucidate the influence of temperature on these properties. This is an important subject in the control...
Deformations of the constraint algebra of Ashtekar's Hamiltonian formulation of general relativity.
Krasnov, Kirill
2008-02-29
We show that the constraint algebra of Ashtekar's Hamiltonian formulation of general relativity can be nontrivially deformed by allowing the cosmological constant to become an arbitrary function of the (Weyl) curvature. Our result implies that there is not one but infinitely many (parametrized by an arbitrary function) four-dimensional generally covariant local gravity theories propagating 2 degrees of freedom.
The Relation Between Rotation Deformity and Nerve Root Stress in Lumbar Scoliosis
Kim, Ho-Joong; Lee, Hwan-Mo; Moon, Seong-Hwan; Chun, Heoung-Jae; Kang, Kyoung-Tak
Even though several finite element models of lumbar spine were introduced, there has been no model including the neural structure. Therefore, the authors made the novel lumbar spine finite element model including neural structure. Using this model, we investigated the relation between the deformity pattern and nerve root stress. Two lumbar models with different types of curve pattern (lateral bending and lateral bending with rotation curve) were made. In the model of lateral bending curves without rotation, the principal compressive nerve root stress on the concave side was greater than the principal tensile stress on the convex side at the apex vertebra. Contrarily, in the lateral bending curve with rotational deformity, the nerve stress on the convex side was higher than that on the concave side. Therefore, this study elicit that deformity pattern could have significantly influence on the nerve root stress in the lumbar spine.
Nanoscale mechanism and intrinsic structure related deformation of Ti-alloys
Energy Technology Data Exchange (ETDEWEB)
Eckert, J. [IFW Dresden, Institut fuer Komplexe Materialien, Postfach 27 01 16, D-01171 Dresden (Germany)], E-mail: j.eckert@ifw-dresden.de; Das, J. [IFW Dresden, Institut fuer Komplexe Materialien, Postfach 27 01 16, D-01171 Dresden (Germany); Xu, W. [University of Melbourne, Department of Mechanical and Manufacturing Engineering, Vic 3010 (Australia); Theissmann, R. [Forschungszentrum Karlsruhe, Institut fuer Nanotechnologie, Postfach 3640, Karlsruhe D-76133 (Germany)
2008-10-15
A series of Ti-Nb-Ta-(In/Cr) and Ti-Fe-(Sn) alloys containing a bcc {beta}-Ti phase with a grain size ranging from the nanometer/ultrafine regime to the micrometer scale has been prepared by slow cooling from the melt. The plastic deformation behavior has been investigated under compression and the deformation-induced microstructure evolution was checked by X-ray diffraction, scanning and transmission electron microscopy. The data reveal that the underlying mechanisms related to plasticity or brittleness of the {beta}-phase depends significantly on the supersaturation, the local lattice strain, the ease of dislocation slip, as well as twinning and diffusionless transformation triggering grain refinement. The intrinsic structure, the short-range order and the stability of the {beta}-Ti phase have a strong influence on the mode of plastic deformation of the investigated Ti-alloys.
RELATION OF FAT AND NON-FAT BODY COMPOSITION IN WOMEN WITH X-LEG DEFORMITIES
Directory of Open Access Journals (Sweden)
Abdulla Elezi
2013-07-01
Full Text Available Influence of x-leg deformity in relation to fat and non-fat body composition in women was the goal of the paper. In this regards, the research included 41 female students with x-leg deformity and 41 female students without the deformity, while the total number of participants of the research was 82 aged from 18 to 19 years. 6 anthropometric variables have been used; one form measuring the body volme, three variables regarding the dimension of the sub skin fat tissue, one variable for measurement of non-fat body composition and one variable for measurement of fat body mass. Anthropometric measurements were carried out according to International Biological Program (IBP. Data collected demonstrates that x-leg deformity in women have significant influence on relation of fat and non-fat body composition. This relation is manifested as a result of decreased capacity of muscle endurance of leg muscles as main parts responsible for the physical activities, then consumption of calories and insufficient burning of fat as result of decreased capacity of movement.
A general numerical solution of dispersion relations for the nuclear optical model
Capote, R; Quesada, J M; Capote, Roberto; Molina, Alberto; Quesada, Jose Manuel
2001-01-01
A general numerical solution of the dispersion integral relation between the real and the imaginary parts of the nuclear optical potential is presented. Fast convergence is achieved by means of the Gauss-Legendre integration method, which offers accuracy, easiness of implementation and generality for dispersive optical model calculations. The use of this numerical integration method in the optical-model parameter search codes allows for a fast and accurate dispersive analysis. PACS number(s): 11.55.Fv, 24.10.Ht, 02.60.Jh
Stellar populations across the black hole mass - velocity dispersion relation
Martín-Navarro, Ignacio; Bosch, Remco C E van den; Romanowsky, Aaron J; Forbes, Duncan A
2016-01-01
Coevolution between supermassive black holes (BHs) and their host galaxies is universally adopted in models for galaxy formation. In the absence of feedback from active galactic nuclei, simulated massive galaxies keep forming stars in the local Universe. From an observational point of view, however, such coevolution remains unclear. We present a stellar population analysis of galaxies with direct BH mass measurements and the BH mass-{\\sigma} relation as a working framework. We find that over-massive BH galaxies, i.e., galaxies lying above the best-fitting BH mass-{\\sigma} line, tend to be older and more {\\alpha}-element enhanced than under-massive BH galaxies. The scatter in the BH mass-{\\sigma}-[{\\alpha}/Fe] plane is significantly lower than in the standard BH mass-{\\sigma} relation. We interpret this trend as an imprint of active galactic nucleus feedback on the star formation histories of massive galaxies.
Classical Tests of General Relativity: Brane-World Sun from Minimal Geometric Deformation
Casadio, Roberto; da Rocha, Roldao
2015-01-01
We consider a solution of the effective four-dimensional brane-world equations, obtained from the General Relativistic Schwarzschild metric via the principle of Minimal Geometric Deformation, and investigate the corresponding signatures stemming from the possible existence of a warped extra dimension. In particular, we derive bounds on an extra-dimensional parameter, closely related with the fundamental gravitational length, from the experimental results of the classical tests of General Relativity in the Solar system.
Classical tests of general relativity: Brane-world Sun from minimal geometric deformation
Casadio, R.; Ovalle, J.; da Rocha, Roldão
2015-05-01
We consider a solution of the effective four-dimensional brane-world equations, obtained from the general relativistic Schwarzschild metric via the principle of minimal geometric deformation, and investigate the corresponding signatures stemming from the possible existence of a warped extra-dimension. In particular, we derive bounds on an extra-dimensional parameter, closely related with the fundamental gravitational length, from the experimental results of the classical tests of general relativity in the Solar system.
Fang, Xue-Qian; Liu, Yue; Liu, Xiang-Lin; Liu, Jin-Xi
2015-02-01
Interface between the constituents plays an important role in the non-destructive detection of smart piezoelectric/piezomagnetic devices. The propagation of SH waves in nano-sized cylindrically multiferroic composites consisting of a piezoelectric layer and a piezomagnetic central cylinder is investigated, and the size-dependent dispersion relation with interface effect is derived. The general solutions of decoupled governing equation in different regions are expressed by using Bessel functions, and the unknown coefficients are determined by satisfying the boundary conditions at the inner interface with negligible thickness and the outer surface of the structure. Through the numerical examples of dispersion relation, it is found that the interface around the nano-cylinder may remarkably reduce the phase velocity, depending on the combination of the value of thickness ratio and the surface condition. The interface shows different effect on the first and second modes of dispersion relation.
In-medium dispersion relations of charmonia studied by the maximum entropy method
Ikeda, Atsuro; Asakawa, Masayuki; Kitazawa, Masakiyo
2017-01-01
We study in-medium spectral properties of charmonia in the vector and pseudoscalar channels at nonzero momenta on quenched lattices, especially focusing on their dispersion relation and the weight of the peak. We measure the lattice Euclidean correlation functions with nonzero momenta on the anisotropic quenched lattices and study the spectral functions with the maximum entropy method. The dispersion relations of charmonia and the momentum dependence of the weight of the peak are analyzed with the maximum entropy method together with the errors estimated probabilistically in this method. We find a significant increase of the masses of charmonia in medium. We also find that the functional form of the charmonium dispersion relations is not changed from that in the vacuum within the error even at T ≃1.6 Tc for all the channels we analyze.
In-medium dispersion relations of charmonia studied by maximum entropy method
Ikeda, Atsuro; Kitazawa, Masakiyo
2016-01-01
We study in-medium spectral properties of charmonia in the vector and pseudoscalar channels at nonzero momenta on quenched lattices, especially focusing on their dispersion relation and weight of the peak. We measure the lattice Euclidean correlation functions with nonzero momenta on the anisotropic quenched lattices and study the spectral functions with the maximum entropy method. The dispersion relations of charmonia and the momentum dependence of the weight of the peak are analyzed with the maximum entropy method together with the errors estimated probabilistically in this method. We find significant increase of the masses of charmonia in medium. It is also found that the functional form of the charmonium dispersion relations is not changed from that in the vacuum within the error even at $T\\simeq1.6T_c$ for all the channels we analyzed.
Dispersion relations with crossing symmetry for pipi D and F wave amplitudes
Kaminski, R
2011-01-01
A set of once subtracted dispersion relations with imposed crossing symmetry condition for the pipi D- and F-wave amplitudes is derived and analyzed. An example of numerical calculations in the effective two pion mass range from the threshold to 1.1 GeV is presented. It is shown that these new dispersion relations impose quite strong constraints on the analyzed pipi interactions and are very useful tools to test the pipi amplitudes. One of the goals of this work is to provide a complete set of equations required for easy use. Full analytical expressions are presented. Along with the well known dispersion relations successful in testing the pipi S- and P-wave amplitudes, those presented here for the D and F waves give a complete set of tools for analyzes of the pipi interactions.
,
2012-01-01
During previous numerical experiments on isotropic turbulence of surface gravity waves we observed formation of the long wave background (condensate). It was shown (Korotkevich, Phys. Rev. Lett. vol. 101 (7), 074504 (2008)), that presence of the condensate changes a spectrum of direct cascade, corresponding to the flux of energy to the small scales from pumping region (large scales). Recent experiments show that the inverse cascade spectrum is also affected by the condensate. In this case mechanism proposed as a cause for the change of direct cascade spectrum cannot work. But inverse cascade is directly influenced by the linear dispersion relation for waves, as a result direct measurement of the dispersion relation in the presence of condensate is necessary. We performed the measurement of this dispersion relation from the direct numerical experiment. The results demonstrate that in the region of inverse cascade influence of the condensate cannot be neglected.
Dispersion relations at finite temperature and density for nucleons and pions
Hurtado, R; Quimbay, C; Hurtado, Rafael; Morales, John; Quimbay, Carlos
2000-01-01
We calculate the nucleonic and pionic dispersion relations at finite temperature T and non-vanishing chemical potentials $(\\mu_f)$ in the context of an effective chiral theory that describes the strong and electromagnetic interactions for nucleons and pions. The dispersion relations are calculated in the broken chiral symmetry phase, where the nucleons are massive and pions are taken as massless. The calculation is performed at lowest order in the energy expansion, working in the framework of the real time formalism of thermal field theory in the Feynman gauge. These one-loop dispersion relations are obtained at leading order with respect to T and $\\mu_f$. We also evaluate the effective masses of the quasi-nucleon and quasi-pion excitations in thermal and chemical conditions as the ones of a neutron star.
Lim, C. W.; Wu, B. S.; He, L. H.
2001-12-01
A novel approach is presented for obtaining approximate analytical expressions for the dispersion relation of periodic wavetrains in the nonlinear Klein-Gordon equation with even potential function. By coupling linearization of the governing equation with the method of harmonic balance, we establish two general analytical approximate formulas for the dispersion relation, which depends on the amplitude of the periodic wavetrain. These formulas are valid for small as well as large amplitude of the wavetrain. They are also applicable to the large amplitude regime, which the conventional perturbation method fails to provide any solution, of the nonlinear system under study. Three examples are demonstrated to illustrate the excellent approximate solutions of the proposed formulas with respect to the exact solutions of the dispersion relation. (c) 2001 American Institute of Physics.
DEFF Research Database (Denmark)
Marini, Lorenzo; Bruun, Hans Henrik; Heikkinen, Risto
2012-01-01
Aim Habitat fragmentation is a major driver of biodiversity loss but it is insufficiently known how much its effects vary among species with different life-history traits; especially in plant communities, the understanding of the role of traits related to species persistence and dispersal...... in determining dynamics of species communities in fragmented landscapes is still limited. The primary aim of this study was to test how plant traits related to persistence and dispersal and their interactions modify plant species vulnerability to decreasing habitat area and increasing isolation. Location Five...... of habitat loss on plant species richness was pervasive across different regions, whereas the effect of habitat isolation on species richness was not evident. This area effect was, however, not equal for all the species, and life-history traits related to both species persistence and dispersal modified plant...
Grinyaev, Konstantin V.; Smirnov, Ivan V.; Radishevsky, Vladislav L.; Ditenberg, Ivan A.; Tyumentsev, Alexander N.; Chernov, Vyacheslav M.; Korznikov, Alexander V.
2016-11-01
Study of microstructure transformation and microhardness changes of dispersion-hardened V-Cr-Zr-W alloy after severe plastic deformation by torsion on Bridgman anvils and subsequent heat treatments was conducted. Basic stages of relaxation processes were revealed: at 800°C recovery processes take place and primary recrystallization begins; at 900°C primary recrystallization intensifies; in range of 950-1050°C collective recrystallization processes activate; at 1200°C secondary recrystallization starts. Microhardness measurement and comparison of its values with structural states features were conducted. Strengthening mechanisms and their contribution at various stages of defect substructure relaxation are discussed. It is shown that increase of thermal stability of V-Cr-Zr-W alloy microstructure is a consequence of the formation of high density of thermally stable Zr (O-N-C)-based nanoparticles.
The general dispersion relation of induced streaming instabilities in quantum outflow systems
Energy Technology Data Exchange (ETDEWEB)
Mehdian, H., E-mail: mehdian@khu.ac.ir; Hajisharifi, K.; Hasanbeigi, A. [Department of Physics and Institute for Plasma Research, Kharazmi University, 49 Dr Mofatteh Avenue, Tehran 15614 (Iran, Islamic Republic of)
2015-11-15
In this manuscript the dispersion relations of streaming instabilities, by using the unique property (neutralized in charge and current by default) of plasma shells colliding, have been generalized and studied. This interesting property for interpenetrating beams enables one to find the general dispersion relations without any restrictions used in the previous works in this area. In our previous work [H. Mehdian et al., ApJ. 801, 89 (2015)], employing the plasma shell concept and boost frame method, the general dispersion relation for filamentation instability has been derived in the relativistic classical regime. But in this paper, using the above mentioned concepts, the general dispersion relations (for each of streaming instabilities, filamentation, two-stream and multi-stream) in the non-relativistic quantum regime have been derived by employing the quantum fluid equations together with Maxwell equations. The derived dispersion relations enable to describe any arbitrary system of interacting two and three beams, justified neutralization condition, by choosing the inertial reference frame embedded on the one of the beams. Furthermore, by the numerical and analytical study of these dispersion relations, many new features of streaming instabilities (E.g. their cut-off wave numbers and growth rates) in terms of all involved parameters have been illustrated. The obtained results in this paper can be used to describe many astrophysical systems and laboratory astrophysics setting, such as collision of non-parallel plasma shells over a background plasma or the collision of three neutralized plasma slabs, and justifying the many plasma phenomena such as particle accelerations and induced fields.
On integrable deformations of superstring sigma models related to AdS_n x S^n supercosets
Hoare, B
2015-01-01
We consider two integrable deformations of 2d sigma models on supercosets associated with AdS_n x S^n. The first, the "eta-deformation" (based on the Yang-Baxter sigma model), is a one-parameter generalization of the standard superstring action on AdS_n x S^n, while the second, the "lambda-deformation" (based on the deformed gauged WZW model), is a generalization of the non-abelian T-dual of the AdS_n x S^n superstring. We show that the eta-deformed model may be obtained from the lambda-deformed one by a special scaling limit and analytic continuation in coordinates combined with a particular identification of the parameters of the two models. The relation between the couplings and deformation parameters is consistent with the interpretation of the first model as a real quantum deformation and the second as a root of unity quantum deformation. For the AdS_2 x S^2 case we then explore the effect of this limit on the supergravity background associated to the lambda-deformed model. We also suggest that the two m...
Flow rate-pressure drop relation for deformable shallow microfluidic channels
Christov, Ivan C.; Cognet, Vincent; Stone, Howard A.
2013-11-01
Laminar flow in devices fabricated from PDMS causes deformation of the passage geometry, which affects the flow rate-pressure drop relation. Having an accurate flow rate-pressure drop relation for deformable microchannels is of importance given that the flow rate for a given pressure drop can be as much as 500% of the flow rate predicted by Poiseuille's law for a rigid channel. proposed a successful model of the latter phenomenon by heuristically coupling linear elasticity with the lubrication approximation for Stokes flow. However, their model contains a fitting parameter that must be found for each channel shape by performing an experiment. We present a perturbative derivation of the flow rate-pressure drop relation in a shallow deformable microchannel using Kirchoff-Love theory of isotropic quasi-static plate bending and Stokes' equations under a ``double lubrication'' approximation (i.e., the ratio of the channel's height to its width and of the channel's width to its length are both assumed small). Our result contains no free parameters and confirms Gervais et al.'s observation that the flow rate is a quartic polynomial of the pressure drop. ICC was supported by NSF Grant DMS-1104047 and the U.S. DOE through the LANL/LDRD Program; HAS was supported by NSF Grant CBET-1132835.
The Effects of Relative Humidity on the Flowability and Dispersion Performance of Lactose Mixtures.
Lu, Xiang-Yun; Chen, Lan; Wu, Chuan-Yu; Chan, Hak-Kim; Freeman, Tim
2017-05-29
The flowability and dispersion behavior are two important physicochemical properties of pharmaceutical formulations for dry powder inhalers (DPIs). They are usually affected by the environmental conditions, such as temperature and relative humidity (RH). However, very few studies have been focused on the relationship between the two properties and their dependence on RH during storage. In this research, model pharmaceutical formulations were prepared using mixtures of coarse and fine lactose. The fractions of fines in the mixtures were 0%, 5%, 10%, and 20%, respectively. These blends were stored at four different RH levels, 0%, 30%, 58%, and 85%, for 48 h. The FT4 Powder Rheometer was used to evaluate the powder flowability, and the Malvern Spraytec(®) laser diffraction system was employed to assess the powder dispersion performance. The results indicated that both the flow and dispersion properties of lactose blends deteriorate after being stored at 85% RH, but improved after being conditioned at 58% RH. The fine particle fractions (FPFs) of the blends with 5% and 10% fine fractions and the as-received coarse lactose decreased when they were conditioned at 30% RH. For the blend with 20% fine fraction, a high RH during storage (i.e., 85% RH) affected the dispersion property, but had a limited influence on its flowability, while, for the coarse lactose powder, the different RH conditions affected its flowability, but not the dispersion results. A strong correlation between the powder flowability and its dispersion performance was found.
Surface plasmon polariton dispersion relation at organic/dielectric/metal interfaces
DEFF Research Database (Denmark)
Kostiučenko, Oksana; Fiutowski, Jacek; Kawalec, Tomasz;
2014-01-01
The dispersion relation of a hybrid photonic–plasmonic system consisting of a light emitting thin organic para-Hexaphenylene (p-6P) layer separated by a dielectric gap from a plasmonic silver film is investigated using leakage radiation spectroscopy. Experimental studies are complemented by numer......The dispersion relation of a hybrid photonic–plasmonic system consisting of a light emitting thin organic para-Hexaphenylene (p-6P) layer separated by a dielectric gap from a plasmonic silver film is investigated using leakage radiation spectroscopy. Experimental studies are complemented...
Forward dispersion relations for pion-kaon scattering and the K*0(800) resonance
Rodas, A
2016-01-01
We review our recent analysis of $\\pi K$ scattering data in terms of forward dispersion relations, and also present the parameters of the strange resonances. This work consists of fits to the data that are constrained to satisfy analyticity requirements. The method yields a set of simple and consistent parameterizations that are compatible with forward dispersion relations up to 1.6 GeV while still describing the data. We also obtain the pole parameters of the $K^*_0(800)$ and the $K^*(892)$ resonances.
Dispersion relations with crossing symmetry for pipi D and F wave amplitudes
Kaminski, R.
2011-01-01
A set of once subtracted dispersion relations with imposed crossing symmetry condition for the pipi D- and F-wave amplitudes is derived and analyzed. An example of numerical calculations in the effective two pion mass range from the threshold to 1.1 GeV is presented. It is shown that these new dispersion relations impose quite strong constraints on the analyzed pipi interactions and are very useful tools to test the pipi amplitudes. One of the goals of this work is to provide a complete set o...
Dispersion relations for stationary light in one-dimensional atomic ensembles
Iakoupov, Ivan; Ott, Johan R.; Chang, Darrick E.; Sørensen, Anders S.
2016-11-01
We investigate the dispersion relations for light coupled to one-dimensional ensembles of atoms with different level schemes. The unifying feature of all the considered setups is that the forward and backward propagating quantum fields are coupled by the applied classical drives such that the group velocity can vanish in an effect known as "stationary light." We derive the dispersion relations for all the considered schemes, highlighting the important differences between them. Furthermore, we show that additional control of stationary light can be obtained by treating atoms as discrete scatterers and placing them at well-defined positions. For the latter purpose, a multimode transfer matrix theory for light is developed.
Institute of Scientific and Technical Information of China (English)
SHU Wei-Xing; LUO Hai-Lu; LI Fei; REN Zhong-Zhou
2006-01-01
@@ We investigate the propagation of electromagnetic waves at the interface between an isotropic material and the anisotropic medium with a unique dispersion relation. We show that the refraction behaviour of E-polarized waves is opposite to that of H-polarized waves, though the dispersion relations for E- and H-polarized waves are the same. It is found that waves exhibit different propagation properties in anisotropic media with different sign combinations of the permittivity and permeability tensors. Some interesting properties of propagation are also found in the special anisotropic media, leading to potential applications.
Energy Technology Data Exchange (ETDEWEB)
Dryepondt, Sebastien N [ORNL; Boegelein, T [University of Liverpool, UK; Pandey, Amit [LGFCS; Dawson, K [University of Liverpool, UK; Tatlock, G.J. [University of Liverpool, UK
2015-01-28
Oxide dispersion strengthened (ODS) ferritic steels typically contain a fine dispersion of nanoscopic Y(Al, Ti) oxides, leading to an improvement in mechanical and physical properties. For a rapid prototyping technique, selective laser melting (SLM), was successfully applied to consolidate as-mechanically alloyed ODS-PM2000 (Fe 19Cr 5.5Al 0.5Ti 0.5Y_{2}O_{3}; all wt.%) powder to fabricate solid and thin-walled builds of different thickness. Our work is intended to act as a first study to investigate the tensile response of such configurations at room temperature, using miniaturized test specimens along and perpendicular to the growth direction. The 0.2% offset yield strength of as-grown wall builds was inferior to conventional PM2000 alloy (recrystallized), but could be significantly increased by conducting post-build heat treatments. Young s modulus and yield strength showed anisotropy and were enhanced when testing perpendicular to the build growth direction. Electron backscatter diffraction revealed a strong [001] fibre texture along the growth direction, which explains the anisotropic behaviour. In addition, studies on the morphology of the individual fracture surfaces, the grain structure of the cross-section near this region and the size distribution of ODS particles in such builds were conducted. A fine dispersion of precipitates was retained in all SLM builds, and findings suggest that a certain amount of Y is probably still in atomic solution in the as-grown condition and forms new small nanoscopic dispersoids during annealing, which lead to enhanced strengthening.
Gyro-viscosity and linear dispersion relations in pair-ion magnetized plasmas
Kono, M
2015-01-01
A fluid theory has been developed by taking account of gyro-viscosity to study wave propagation characteristics in a homogeneous pair-ion magnetized plasma with a cylindrical symmetry. The exact dispersion relations derived by the Hankel-Fourier transformation are shown comparable with those observed in the experiment by Oohara and co-workers. The gyro-viscosity is responsible for the change in propagation characteristics of the ion cyclotron wave from forward to backward by suppressing the effect of the thermal pressure which normally causes the forward nature of dispersion. Although the experiment has been already explained by a kinetic theory by the present authors, the kinetic derivations are so involved because of exact particle orbits in phase space, finite Larmor radius effects, and higher order ion cyclotron resonances. The present fluid theory provides a simple and transparent structure to the dispersion relations since the gyro-viscosity is renormalized into the ion cyclotron frequency which itself ...
Deformation of the Calabrian Arc subduction complex and its relation to STEP activity at depth.
Polonia, Alina; Wortel, Rinus; Nijholt, Nicolai; Govers, Rob; Torelli, Luigi
2015-04-01
Propagating tear faults at the edge of subducted slabs ("Subduction transform edge propagator", STEP) are an intrinsic part of lithospheric plate dynamics. The surface expression of a STEP is generally not known yet, and is expected to vary significantly from one region to the other. We choose the Sicily -Calabria-Ionian Sea region, of which the lithosphere-upper mantle structure has the characteristics of a STEP zone, as a study area. The area has a very prominent accretionary wedge, the formation and subsequent deformation of which presumably were affected by the STEP activity at depth. In this contribution, we use seismic data on the near surface structure and deformation in combination with numerical model results to investigate the relation between deep STEP activity and near surface expression. Prominent features in the surface tectonics are the Malta escarpment (with predominantly normal faulting), the newly identified Ionian Fault and Alfeo-Etna fault system, and a distinct longitudinal division of the wedge into a western and an eastern lobe (Polonia et al., Tectonics, 2011). The two lobes are characterized by different structural style, deformation rates and basal detachment depths. Numerical model results indicate that the regional lithospheric structure, such as the orientation of the eastern passive (albeit subsequently activated) margin of Sicily relative to the Calabrian subduction zone, has a profound effect on possible fault activity along the Malta escarpment. Fault activity along the above primary fault structures may have varied in time, implying the possibility of intermittent activity. Interpreting seismicity in the context of a possible STEP, and the accompanying deformation zone at or near the surface, is not (yet) straightforward. Although direct evidence for recognizing all aspects of STEP activity is - as usual - lacking, a comparison with two well-known STEP regions, the northern part of the Tonga subduction zone and southern part of the
Energy Technology Data Exchange (ETDEWEB)
Vieira, E.; Durazzo, M., E-mail: evieira@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)
2010-07-01
The Nuclear and Energy Research Institute - IPEN-CNEN/SP produces routinely the nuclear fuel necessary for operating its research reactor, IEA-R1. This fuel consists of fuel plates containing U{sub 3}Si{sub 2}-Al composites as the meat, which are fabricated by rolling. The rolling process currently deployed was developed with base on information obtained from literature, which were used as premises for defining the current manufacturing procedures, according to a methodology with essentially empirical character. Despite the current rolling process to be perfectly stable and highly reproducible, it is not well characterized and therefore is not fully known. The objective of this work is to characterize the rolling process for producing fuel plates, presenting results of the evolution of all parameters of technological interest, after each rolling pass, obtaining information along the fuel plate deformation during the rolling process. (author)
Black Hole Radiation with Modified Dispersion Relation in Tunneling Paradigm: Static Frame
Wang, Peng
2015-01-01
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appears that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study possible deviations from the Hawking's prediction, the dispersive field theory models have been proposed, following the Unruh's hydrodynamic analogue of a black hole radiation. In the dispersive field theory models, the dispersion relations of matter fields are modified at high energies, which leads to modifications of equations of motion. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the static frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energies but is modified near the Planck mass $m_{p}$. We calculate the corrections to the Hawking temperature for massive and charged particles to $\\mathcal{O}\\left(m_{p}^{-2}\\right) $ and massless and neutral particles to all orders. Our res...
Time-dependent q-deformed coherent states for generalized uncertainty relations
Dey, Sanjib; Gouba, Laure; Castro, Paulo G
2012-01-01
We investigate properties of generalized time-dependent q-deformed coherent states for a noncommutative harmonic oscillator. The states are shown to satisfy a generalized version of Heisenberg's uncertainty relations. For the initial value in time the states are demonstrated to be squeezed, i.e. the inequalities are saturated, whereas when time evolves the uncertainty product oscillates away from this value albeit still respecting the relations. For the canonical variables on a noncommutative space we verify explicitly that Ehrenfest's theorem hold at all times. We conjecture that the model exhibits revival times to infinite order. Explicit sample computations for the fractional revival times and superrevival times are presented.
Magnon dispersion relation and exchange interactions in MnF2
DEFF Research Database (Denmark)
Nikotin, O.; Lindgård, Per-Anker; Dietrich, O. W.
1969-01-01
The magnon dispersion relation for MnF2 at 4·2 °K has been measured by means of the triple-axis neutron scattering technique along the symmetry lines in the (010) plane of the Brillouin zone. Using an exact dipole model, the three nearest-neighbour exchange constants were found to be J1 = 0·028 ±...
The Quantum Yang Baxter conditions and the dispersion relations for the Nambu-Goldstone bosons
Arraut, Ivan
2016-01-01
We demonstrate that the extensions of the spontaneous symmetry breaking condition, when applied to the non-relativistic systems, have a correspondence with the Yang-Baxter conditions. This correspondence guarantees the appropriate dispersion relation and the appropriate counting for the Nambu-Goldstones bosons.
Big Bang Nucleosynthesis in the presence of sterile neutrinos with altered dispersion relations
Aeikens, Elke; Pakvasa, Sandip; Weiler, Thomas J
2016-01-01
Big Bang Nucleosynthesis imposes stringent bounds on light sterile neutrinos mixing with the active flavors. Here we discuss how altered dispersion relations can weaken such bounds and allow compatibility of new sterile neutrino degrees of freedom with a successful generation of the light elements in the early Universe.
Phonon Dispersion Relation for Copper Measured by Triple Axis Spectrometer at CARR
Institute of Scientific and Technical Information of China (English)
MA; Xiao-bai; HAO; Li-jie; GAO; Jian-bo; LI; Yu-qing; LIU; Xin-zhi; WU; Li-qi
2013-01-01
In 2013,the triple axis spectrometer at China Advanced Research Reactor has been put into operation successfully.After spectrometer commissioning,including modification of the scan programs and determination of the zero point of the spectrometer angles,the frequency/wave-vector dispersion relation in copper at room temperature has been measured.The results are shown in Fig.1.As the
The Dispersion Relation for the 1/sinh(exp 2) Potential in the Classical Limit
Campbell, Joel
2009-01-01
The dispersion relation for the inverse hyperbolic potential is calculated in the classical limit. This is shown for both the low amplitude phonon branch and the high amplitude soliton branch. It is shown these results qualitatively follow that previously found for the inverse squared potential where explicit analytic solutions are known.
Dispersion relation for electromagnetic wave propagation in a strongly magnetized plasma
Marklund, G B M; Shukla, P K
2006-01-01
A dispersion relation for electromagnetic wave propagation in a strongly magnetized cold plasma is deduced, taking photon-photon scattering into account. It is shown that the combined plasma and quantum electrodynamic effect is important for understanding the mode-structures in magnetar and pulsar atmospheres. The implications of our results are discussed.
Morphological Tuning of the Plasmon Dispersion Relation in Dielectric-Loaded Nanofiber Waveguides
DEFF Research Database (Denmark)
Leißner, Till; Lemke, Christoph; Fiutowski, Jacek;
2013-01-01
Understanding the impact of lateral mode confinement in plasmonic waveguides is of fundamental interest regarding potential applications in plasmonic devices. The knowledge of the frequency-wave vector dispersion relation provides the full information on electromagnetic field propagation in a wav...
Backwards and forwards relative dispersion in turbulent flow: An experimental investigation
DEFF Research Database (Denmark)
Berg, J.; Lüthi, B.; Mann, J.;
2006-01-01
From particle tracking velocimetry we present an experimental measure of the ratio between backwards and forwards relative dispersion in an intermediate Reynolds number turbulent flow. Lack of time-reversal symmetry implies that their ratio may be different from 1. From a stochastic model, this has...
Surface plasmon polariton dispersion relation at organic/dielectric/metal interfaces
DEFF Research Database (Denmark)
Kostiučenko, Oksana; Fiutowski, Jacek; Kawalec, Tomasz
2014-01-01
The dispersion relation of a hybrid photonic–plasmonic system consisting of a light emitting thin organic para-Hexaphenylene (p-6P) layer separated by a dielectric gap from a plasmonic silver film is investigated using leakage radiation spectroscopy. Experimental studies are complemented...... by numerical simulations for the same structure but in the complementary, inverted configuration. The numerical simulations use as input ellipsometric measurements providing optical constants of p-6P in a wide spectral range. From a comparison between calculated and measured dispersion curves it is concluded...
Institute of Scientific and Technical Information of China (English)
Liu Jie; Qu Guosheng; Tong Xiaoguang; Song Huizhen; Zhou Qing; Zhang Ning
2004-01-01
Study of seismic activity in the Kuqa area enables us to infer some possible active faults in basement from the ePicentral distribution on different profiles. The relations between active faults in the basement and surface structures are analyzed and the difference between sedimentary cover and basement in their deformation characteristics and the genesis are discussed. The following conclusions have been drawn: (1) the epicentral distribution indicates that, the east Qiulitag and south and north Qiulitag deep faults in the basement correspond to the east and west Qiulitag anticlines, respectively. Moreover, deep faults also exist beneath the Yiqiklik and Yaken anticlines. It indicates that the formation of surface structures is controlled by deep structures; (2) A NE-trending strike-slip fault develops along the line from the western termination of Yiqiklik structure to Dongqiu Well 5 and a NW-trending active fault on the western side of Baicheng. The two active faults across the tectonic strike are the main causes for tectonic segmentation of the Kuqa depression and possibly the cause for the middle segment (Kuqa-Baicheng) of the depression to be more shortened than both its eastern and western terminations; (3) The difference between the sedimentary cover and basement in their deformation characteristics depends mainly on the different properties of media between them.The lithospheric strength of the basement in the basin is fairly high, which determines the basement deformation to be mainly of brittle fracture seismic activity. While the strength of sedimentary cover is low, where there exist weak thin layers, such as coal and gyps. Under the effect of strong tectonic compression, the sedimentary rocks may undergo strong viscous or plastic flow deformation; meanwhile, an aseismic detachment may take place along the weak layers.
Relation of ongoing deformation rates to the subduction zone process in southern Alaska
Sauber, Jeanne; McClusky, Simon; King, Robert
1997-11-01
The rate and orientation of ongoing strain associated with subduction of the Pacific plate and the accretion of the Yakutat terrane to southern Alaska has been estimated at 13 sites from Global Positioning System measurements made in June 1993 and 1995. Along the Gulf of Alaska coast near Cape Yakataga, the average rate of deformation, relative to Fairbanks, was ≈38 mm/yr at N32°W. Further inland, above the region where the dip of the downgoing Pacific plate changes from about 10° to >30°, the deformation rate was ≈12mm/yr at N26°W. In the Sourdough/Paxson area, the deformation rate drops to 2-5 mm/yr and suggests a low short-term deformation rate across the Denali fault. Elastic straining of the overriding plate due to back-slip on a main thrust zone with an average dip of about 10° can account for the overall rate and distribution of short-term compressional strain across south central Alaska. Above the transitional region between unstable and stable sliding we suggest that strain associated with ≈15 mm/yr of right-lateral strike-slip occurs also. If the strain accumulated since the two 1899 earthquakes (both MW=8.1) from the offshore Pamplona fault zone to south of the Border Ranges fault (down-dip width ≈100 km) was seismically released on a single fault it would correspond to a M=8.1 earthquake.
Cyprych, Daria; Piazolo, Sandra; Wilson, Christopher J. L.; Luzin, Vladimir; Prior, David J.
2016-09-01
We utilize in situ neutron diffraction to continuously track the average grain size and crystal preferred orientation (CPO) development in ice, during uniaxial compression of two-phase and pure ice samples. Two-phase samples are composed of ice matrix and 20 vol.% of second phases of two types: (1) rheologically soft, platy graphite, and (2) rigid, rhomb-shaped calcite. The samples were tested at 10 °C below the ice melting point, ambient pressures, and two strain rates (1 ×10-5 and 2.5 ×10-6 s-1), to 10 and 20% strain. The final CPO in the ice matrix, where second phases are present, is significantly weaker, and ice grain size is smaller than in an ice-only sample. The microstructural and rheological data point to dislocation creep as the dominant deformation regime. The evolution and final strength of the CPO in ice depend on the efficiency of the recrystallization processes, namely grain boundary migration and nucleation. These processes are markedly influenced by the strength, shape, and grain size of the second phase. In addition, CPO development in ice is further accentuated by strain partitioning into the soft second phase, and the transfer of stress onto the rigid second phase.
Institute of Scientific and Technical Information of China (English)
Liu Bing-Can; Yu Li; Lu Zhi-Xin
2011-01-01
The analytic surface plasmon polaritons (SPPs) dispersion relation is studied in a system consisting of a thin metallic film bounded by two sides media of nonlinear dielectric of arbitrary nonlinearity is studied by applying a generalised first integral approach. We consider both asymmetric and symmetric structures. Especially, in the symmetric system, two possible modes can exist: the odd mode and the even mode. The dispersion relations of the two modes are obtained. Due to the nonlinear dielectric, the magnitude of the electric field at the interface appears and alters the dispersion relations. The changes in SPPs dispersion relations depending on film thicknesses and nonlinearity are studied.
Dalton, David R.; Slawinski, Michael A.; Stachura, Piotr; Stanoev, Theodore
2016-01-01
We examine two types of guided waves: the Love and the quasi-Rayleigh waves. Both waves propagate in the same model of an elastic isotropic layer above an elastic isotropic halfspace. From their dispersion relations, we calculate their speeds as functions of the elasticity parameters, mass densities, frequency and layer thickness. We examine the sensitivity of these relations to the model and wave properties.
Dispersion Models to Forecast Traffic-related Emissions in Urban Areas
Directory of Open Access Journals (Sweden)
Davide Scannapieco
2011-11-01
Full Text Available Down the centuries, a direct link had been developed between increase in mobility and increase in wealth. On the other hand, air emission of greenhouse gases (GHG due to vehicles equipped with internal combustion engines can be regarded as a negative pressure over the environment. In the coming decades, road transport is likely to remain a significant contributor to air pollution in cities. Many urban trips cover distances of less than 6 km. Since the effectiveness of catalytic converters in the initial minutes of engine operation is small, the average emission per distance driven is very high in urban areas. Also, poorly maintained vehicles that lack exhaust aftertreatment systems are responsible for a major part of pollutant emissions. Therefore in urban areas, where higher concentrations of vehicles can be easily found, air pollution represents a critical issue, being it related with both environment and human health protection: in truth, research in recent decades consistently indicates the adverse effects of outdoor air pollution on human health, and the evidence points to air pollution stemming from transport as an important contributor to these effects. Several institutions (EEA, USEPA, etc. focused their interest in dispersion models because of their potential effectiveness to forecast atmospheric pollution. Furthermore, air micropollutants such as Polycyclic Aromatic Compounds (PAH and Metallic Trace Elements (MTE are traffic-related and although very low concentrations their dispersion is a serious issue. However, dispersion models are usefully implemented to better manage this estimation problem. Nonetheless, policy makers and land managers have to deal with model selection, taking into account that several dispersion models are available, each one of them focused on specific goals (e.g., wind transport of pollutants, land morphology implementation, evaluation of micropollutants transport, etc.; a further aspect to be considered is
Gyro-viscosity and linear dispersion relations in pair-ion magnetized plasmas
Energy Technology Data Exchange (ETDEWEB)
Kono, M. [Faculty of Policy Studies, Chuo University, Tokyo 192-0393 (Japan); Vranjes, J. [Instituto de Astrofisica de Canarias, Tenerife E38205 (Spain); Departamento de Astrofisica, Universidad de La Laguna, Tenerife E38205 (Spain)
2015-11-15
A fluid theory has been developed by taking account of gyro-viscosity to study wave propagation characteristics in a homogeneous pair-ion magnetized plasma with a cylindrical symmetry. The exact dispersion relations derived by the Hankel-Fourier transformation are shown comparable with those observed in the experiment by Oohara and co-workers. The gyro-viscosity is responsible for the change in propagation characteristics of the ion cyclotron wave from forward to backward by suppressing the effect of the thermal pressure which normally causes the forward nature of dispersion. Although the experiment has been already explained by a kinetic theory by the present authors, the kinetic derivations are so involved because of exact particle orbits in phase space, finite Lamor radius effects, and higher order ion cyclotron resonances. The present fluid theory provides a simple and transparent structure to the dispersion relations since the gyro-viscosity is renormalized into the ion cyclotron frequency which itself indicates the backward nature of dispersion. The usual disadvantage of a fluid theory, which treats only fundamental modes of eigen-waves excited in a system and is not able to describe higher harmonics that a kinetic theory does, is compensated by simple derivations and clear picture based on the renormalization of the gyro-viscosity.
Seismic imaging of deformation zones associated with normal fault-related folding
Lapadat, Alexandru; Imber, Jonathan; Iacopini, David; Hobbs, Richard
2016-04-01
bed rotation, affect, presumably, the acoustic properties of the rocks. We calculate the strains associated with fault displacement (using elastic dislocation models) and generate a synthetic seismic section of the model, taking into account the strain-related changes in the acoustic properties of the deformed rocks. Finally, we investigate whether variations in the magnitudes of volumetric strain correlate with the magnitudes of seismic amplitude variations near the analysed faults.
Tidal deformability and I-Love-Q relations for gravastars with polytropic thin shells
Uchikata, Nami; Yoshida, Shijun; Pani, Paolo
2016-09-01
The moment of inertia, the spin-induced quadrupole moment, and the tidal Love number of neutron-star and quark-star models are related through some relations which depend only mildly on the stellar equation of state. These "I-Love-Q" relations have important implications for astrophysics and gravitational-wave astronomy. An interesting problem is whether similar relations hold for other compact objects and how they approach the black hole limit. To answer these questions, here we investigate the deformation properties of a large class of thin-shell gravastars, which are exotic compact objects that do not possess an event horizon nor a spacetime singularity. Working in a small-spin and small-tidal field expansion, we calculate the moment of inertia, the quadrupole moment, and the (quadrupolar electric) tidal Love number of gravastars with a polytropic thin shell. The I-Love-Q relations of a thin-shell gravastar are drastically different from those of an ordinary neutron star. The Love number and quadrupole moment for less compact models have the opposite sign relative to those of ordinary neutron stars, and the I-Love-Q relations continuously approach the black hole limit. We consider a variety of polytropic equations of state for the matter shell and find no universality in the I-Love-Q relations. However, we cannot deny the possibility that, similarly to the neutron-star case, an approximate universality might emerge for a limited class of equations of state. Finally, we discuss how a measurement of the tidal deformability from the gravitational-wave detection of a compact-binary inspiral can be used to constrain exotic compact objects like gravastars.
Energy Technology Data Exchange (ETDEWEB)
Regle, H.
1994-12-31
The ferritic oxide dispersion strengthened alloys are promising candidates for high temperature application materials, in particular for long life core components of advanced nuclear reactors. The aim of this work is to control the microstructure, in order to optimise the mechanical properties. The two ferritic alloys examined here, MA956 and MA957, are obtained by Mechanical Alloying techniques. They are characterised by quite anisotropic microstructure and mechanical properties. We have investigated the influence of hot and cold working processes (hot extrusion, swaging and cold-drawing) and recrystallization heat treatments on deformation textures, microstructures and tensile properties. The aim was to control the size of the grains and their anisotropic shape, using recrystallization heat treatments. After consolidation and hot extrusion, as-received materials present a extremely fine microstructure with elongated grains and a very strong (110) deformation texture with single-crystal character. At that stage of processing, recrystallization temperature are very high (1450 degrees C for MA957 alloy and 1350 degrees C for MA956 alloy) and materials develop millimetric recrystallized grains. Additional hot extrusion induce a fibre texture. Cold-drawing maintains a fibre texture, but the intensity decreases with increasing cold-work level. For both materials, the decrease of texture intensities correspond to a decrease of the recrystallization temperatures (from 1350 degrees C for a low cold-work level to 750 degrees C for 60 % cold-deformation, case of MA956 alloy) and a refinement of the grain size (from a millimetric size to less than an hundred of micrometer). Swaging develop a cyclic component where the intensity increases with increasing deformation in this case, the recrystallization temperature remains always very high and the millimetric grain size is slightly modified, even though cold-work level increases. (Abstract Truncated)
Earthquake volume, fault plane area, seismic energy, strain, deformation and related quantities
Directory of Open Access Journals (Sweden)
S. J. DUDA
1964-06-01
Full Text Available An effort is made to improve Benioff's method for investigation
of strain release in aftershock sequences. The improvement
may be summarized as follows:
1. Earthquake volume increases with magnitude, instead of being
constant. A relation is given, relating volume to magnitude.
2. A revised energy-magnitude formula is used.
3. The seismic gain ratio, i. e. the ratio between seismic energy and
elastic strain energy, probably increases with magnitude, instead of being
constant. Likewise, the ratio of fault plane area of the main shock to the
vertical section through the aftershock volume increases with magnitude.
4. The seismic energy density, the elastic strain energy density as
well as strain are independent of magnitude.
5. The deformation, i. e. the total strain in the aftershock zone, increases
with magnitude at the same rate as seismic energy and volume do.
As a consequence of these improvements some earlier published strain
release characteristics are reconstructed, this time as deformation characteristics
instead.
Fu, X.; Waters, T.; Gary, S. P.
2014-12-01
Collisionless space plasmas often deviate from Maxwellian-like velocity distributions. To study kinetic waves and instabilities in such plasmas, the dispersion relation, which depends on the velocity distribution, needs to be solved numerically. Most current dispersion solvers (e.g. WHAMP) take advantage of mathematical properties of the Gaussian (or generalized Lorentzian) function, and assume that the velocity distributions can be modeled by a combination of several drift-Maxwellian (or drift-Lorentzian) components. In this study we are developing a kinetic dispersion solver that admits nearly arbitrary non-relativistic parallel velocity distributions. A key part of any dispersion solver is the evaluation of a Hilbert transform of the velocity distribution function and its derivative along Landau contours. Our new solver builds upon a recent method to compute the Hilbert transform accurately and efficiently using the fast Fourier transform, while simultaneously treating the singularities arising from resonances analytically. We have benchmarked our new solver against other codes dealing with Maxwellian distributions. As an example usage of our code, we will show results for several instabilities that occur for electron velocity distributions observed in the solar wind.
Touil, B.; Bendib, A.; Bendib-Kalache, K.
2017-02-01
The longitudinal dielectric function is derived analytically from the relativistic Vlasov equation for arbitrary values of the relevant parameters z = m c 2 / T , where m is the rest electron mass, c is the speed of light, and T is the electron temperature in energy units. A new analytical approach based on the Legendre polynomial expansion and continued fractions was used. Analytical expression of the electron distribution function was derived. The real part of the dispersion relation and the damping rate of electron plasma waves are calculated both analytically and numerically in the whole range of the parameter z . The results obtained improve significantly the previous results reported in the literature. For practical purposes, explicit expressions of the real part of the dispersion relation and the damping rate in the range z > 30 and strongly relativistic regime are also proposed.
Correction of Cardy–Verlinde formula for Fermions and Bosons with modified dispersion relation
Energy Technology Data Exchange (ETDEWEB)
Sadatian, S. Davood, E-mail: sd-sadatian@um.ac.ir; Dareyni, H.
2017-05-15
Cardy–Verlinde formula links the entropy of conformal symmetry field to the total energy and its Casimir energy in a D-dimensional space. To correct black hole thermodynamics, modified dispersion relation can be used which is proposed as a general feature of quantum gravity approaches. In this paper, the thermodynamics of Schwarzschild four-dimensional black hole is corrected using the modified dispersion relation for Fermions and Bosons. Finally, using modified thermodynamics of Schwarzschild four-dimensional black hole, generalization for Cardy–Verlinde formula is obtained. - Highlights: • The modified Cardy–Verlinde formula obtained using MDR for Fermions and Bosons. • The modified entropy of the black hole used to correct the Cardy–Verlinde formula. • The modified entropy of the CFT has been obtained.
Dispersion Relation of σ Meson and Pion at Finite Nuclear Density in Chiral σ Model
Institute of Scientific and Technical Information of China (English)
DONG Dong-Qiao; CHEN Wei; WEN De-Hua; LIU Liang-Gang; Masahiro Nakano
2004-01-01
The propagators of pion and sigma meson at a finite nuclear density and zero temperature are studied in chiral σ model. Their dispersion relations are calculated numerically in one-loop approximation. In order to avoid the so-called tachyon pole appearing in the one-loop propagators of pion and sigma meson, we regard the mass of sigma meson mσ as a free parameter and adjust it to fit the nuclear saturation properties. For mσ equal to 3075 MeV, the tachyonpole does not appear at the normal nuclear density. Thus the dispersion relation can be calculated in chiral σ model in one-loop level for the first time.
Dispersion relations and entropy of scalar fields in Rindler and de Sitter spaces
Lenz, F; Yazaki, K
2014-01-01
Properties of scalar fields in Rindler and de Sitter spaces are the subject of this work. Using the "brick wall model'' the dispersion relations are determined and the remarkable properties common to both spaces as well as their differences are discussed. Equipped with these tools the horizon induced thermodynamics is revisited and shown to be dominated by a single mode propagating perpendicular to the horizon. Explicit expressions for the partition function, entropy and heat capacity for massless and massive fields are presented.
Relative seismic velocity variations correlate with deformation at Kīlauea volcano.
Donaldson, Clare; Caudron, Corentin; Green, Robert G; Thelen, Weston A; White, Robert S
2017-06-01
Seismic noise interferometry allows the continuous and real-time measurement of relative seismic velocity through a volcanic edifice. Because seismic velocity is sensitive to the pressurization state of the system, this method is an exciting new monitoring tool at active volcanoes. Despite the potential of this tool, no studies have yet comprehensively compared velocity to other geophysical observables on a short-term time scale at a volcano over a significant length of time. We use volcanic tremor (~0.3 to 1.0 Hz) at Kīlauea as a passive source for interferometry to measure relative velocity changes with time. By cross-correlating the vertical component of day-long seismic records between ~230 station pairs, we extract coherent and temporally consistent coda wave signals with time lags of up to 120 s. Our resulting time series of relative velocity shows a remarkable correlation between relative velocity and the radial tilt record measured at Kīlauea summit, consistently correlating on a time scale of days to weeks for almost the entire study period (June 2011 to November 2015). As the summit continually deforms in deflation-inflation events, the velocity decreases and increases, respectively. Modeling of strain at Kīlauea suggests that, during inflation of the shallow magma reservoir (1 to 2 km below the surface), most of the edifice is dominated by compression-hence closing cracks and producing faster velocities-and vice versa. The excellent correlation between relative velocity and deformation in this study provides an opportunity to understand better the mechanisms causing seismic velocity changes at volcanoes, and therefore realize the potential of passive interferometry as a monitoring tool.
Black hole radiation with modified dispersion relation in tunneling paradigm: Static frame
Tao, Jun; Wang, Peng; Yang, Haitang
2017-09-01
To study possible deviations from the Hawking's prediction, we assume that the dispersion relations of matter fields are modified at high energies and use the Hamilton-Jacobi method to investigate the corresponding effects on the Hawking radiation in this paper. The preferred frame is the static frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energies but is modified near the Planck mass mp. We calculate the corrections to the Hawking temperature for massive and charged particles to O (mp-2) and massless and neutral particles to all orders. Our results suggest that the thermal spectrum of radiations near horizon is robust, e.g. corrections to the Hawking temperature are suppressed by mp. After the spectrum of radiations near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole. We find that the subleading logarithmic term of the entropy does not depend on how the dispersion relations of matter fields are modified. Finally, the luminosities of black holes are computed by using the geometric optics approximation.
Black hole radiation with modified dispersion relation in tunneling paradigm: Static frame
Directory of Open Access Journals (Sweden)
Jun Tao
2017-09-01
Full Text Available To study possible deviations from the Hawking's prediction, we assume that the dispersion relations of matter fields are modified at high energies and use the Hamilton–Jacobi method to investigate the corresponding effects on the Hawking radiation in this paper. The preferred frame is the static frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energies but is modified near the Planck mass mp. We calculate the corrections to the Hawking temperature for massive and charged particles to O(mp−2 and massless and neutral particles to all orders. Our results suggest that the thermal spectrum of radiations near horizon is robust, e.g. corrections to the Hawking temperature are suppressed by mp. After the spectrum of radiations near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole. We find that the subleading logarithmic term of the entropy does not depend on how the dispersion relations of matter fields are modified. Finally, the luminosities of black holes are computed by using the geometric optics approximation.
Neutrino Dispersion Relations at Finite Temperature and Density in the Left-Right Symmetric Model
Villalba-Pardo, F D
2010-01-01
In the framework of the Left-Right Symmetric Model, where left-handed neutrinos are massive via the see-saw mechanism, we determine the effects of temperature and density in the dispersion relations for neutrinos, considering that there exists an excess of leptons over antileptons in the plasma. To achieve this we first calculate the dispersion relations at finite temperature and density, computing the neutrino self-energy at one loop order in perturbation theory, obtaining a fully analytic expression for this self-energy even in the fully broken symmetry case by using the Mellin summation technique. From the dispersion relation found from the self energy we obtain the thermal effective mass for neutrinos at high temperature limit. This result allow us to establish the effect of finite temperature and density for neutrino oscillations in thermal and dense media for this framework. We can do it if we take into account that the oscillation patterns depend explicitly on neutrino masses. As a result, a generaliza...
Dispersion relations for stationary light in one-dimensional atomic ensembles
DEFF Research Database (Denmark)
Lakoupov, Ivan; Ott, Johan Raunkjær; Chang, Darrick E
2016-01-01
We investigate the dispersion relations for light coupled to one-dimensional ensembles of atoms with different level schemes. The unifying feature of all the considered setups is that the forward and backward propagating quantum fields are coupled by the applied classical drives such that the gro...... and placing them at well-defined positions. For the latter purpose, a multimode transfer matrix theory for light is developed.......We investigate the dispersion relations for light coupled to one-dimensional ensembles of atoms with different level schemes. The unifying feature of all the considered setups is that the forward and backward propagating quantum fields are coupled by the applied classical drives such that the group...... velocity can vanish in an effect known as “stationary light.” We derive the dispersion relations for all the considered schemes, highlighting the important differences between them. Furthermore, we show that additional control of stationary light can be obtained by treating atoms as discrete scatterers...
de Waal, C; Rodger, J G; Anderson, B; Ellis, A G
2014-05-01
Dispersal and breeding system traits are thought to affect colonization success. As species have attained their present distribution ranges through colonization, these traits may vary geographically. Although several theories predict associations between dispersal ability, selfing ability and the relative position of a population within its geographic range, there is little theoretical or empirical consensus on exactly how these three variables are related. We investigated relationships between dispersal ability, selfing ability and range position across 28 populations of 13 annual, wind-dispersed Asteraceae species from the Namaqualand region of South Africa. Controlling for phylogeny, relative dispersal ability--assessed from vertical fall time of fruits--was positively related to an index of autofertility--determined from hand-pollination experiments. These findings support the existence of two discrete syndromes: high selfing ability associated with good dispersal and obligate outcrossing associated with lower dispersal ability. This is consistent with the hypothesis that selection for colonization success drives the evolution of an association between these traits. However, no general effect of range position on dispersal or breeding system traits was evident. This suggests selection on both breeding system and dispersal traits acts consistently across distribution ranges. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.
Experimental Determination of Whistler Wave Dispersion Relation in the Solar Wind
Stansby, D.; Horbury, T. S.; Chen, C. H. K.; Matteini, L.
2016-09-01
The origins and properties of large-amplitude whistler wavepackets in the solar wind are still unclear. In this Letter, we utilize single spacecraft electric and magnetic field waveform measurements from the ARTEMIS mission to calculate the plasma frame frequency and wavevector of individual wavepackets over multiple intervals. This allows direct comparison of experimental measurements with theoretical dispersion relations to identify the observed waves as whistler waves. The whistlers are right-hand circularly polarized, travel anti-sunward, and are aligned with the background magnetic field. Their dispersion is strongly affected by the local electron parallel beta in agreement with linear theory. The properties measured are consistent with the electron heat flux instability acting in the solar wind to generate these waves.
Measurement of average density and relative volumes in a dispersed two-phase fluid
Sreepada, Sastry R.; Rippel, Robert R.
1992-01-01
An apparatus and a method are disclosed for measuring the average density and relative volumes in an essentially transparent, dispersed two-phase fluid. A laser beam with a diameter no greater than 1% of the diameter of the bubbles, droplets, or particles of the dispersed phase is directed onto a diffraction grating. A single-order component of the diffracted beam is directed through the two-phase fluid and its refraction is measured. Preferably, the refracted beam exiting the fluid is incident upon a optical filter with linearly varing optical density and the intensity of the filtered beam is measured. The invention can be combined with other laser-based measurement systems, e.g., laser doppler anemometry.
Measurements of Finite Dust Temperature Effects in the Dispersion Relation of the Dust Acoustic Wave
Snipes, Erica; Williams, Jeremiah
2009-04-01
A dusty plasma is a four-component system composed of ions, electrons, neutral particles and charged microparticles. The presence of these charged microparticles gives rise to new plasma wave modes, including the dust acoustic wave. Recent measurements [1, 2] of the dispersion relationship for the dust acoustic wave in a glow discharge have shown that finite temperature effects are observed at higher values of neutral pressure. Other work [3] has shown that these effects are not observed at lower values of neutral pressure. We present the results of ongoing work examining finite temperature effects in the dispersion relation as a function of neutral pressure. [4pt] [1] E. Thomas, Jr., R. Fisher, and R. L. Merlino, Phys. Plasmas 14, 123701 (2007). [0pt] [2] J. D. Williams, E. Thomas Jr., and L. Marcus, Phys. Plasmas 15, 043704 (2008). [0pt] [3] T. Trottenberg, D. Block, and A. Piel, Phys. Plasmas 13, 042105 (2006).
Experimental determination of whistler wave dispersion relation in the solar wind
Stansby, D; Chen, C H K; Matteini, L
2016-01-01
The origins and properties of large amplitude whistler wave packets in the solar wind are still unclear. In this Letter we utilise single spacecraft electric and magnetic field waveform measurements from the ARTEMIS mission to calculate the plasma frame frequency and wavevector of individual wave packets over multiple intervals. This allows direct comparison of experimental measurements with theoretical dispersion relations to identify the observed waves as whistler waves. The whistlers are right-hand circularly polarised, travel anti-sunward and are aligned with the background magnetic field. Their dispersion is strongly affected by the local electron parallel beta in agreement with linear theory. The properties measured are consistent with the electron heat flux instability acting in the solar wind to generate these waves.
Concrete floor-bovine claw contact pressures related to floor roughness and deformation of the claw.
Franck, A; De Belie, N
2006-08-01
The intention of this research was to study the impact of concrete floor surface roughness on a bovine claw model and to assess the deformation of the bovine claw model under load. The pressure distribution between the floor and the claw is the key method in this research. Monitoring foot-to-ground pressure distributions may provide insight into the relation between high local pressures and foot lesions. Concrete floor samples were made with 5 different finishing methods. Their roughness was determined by measuring the heights of the "peaks and the valleys" of the surface with a high-precision laser beam. The smoothest surface was the sample finished with a metal float (surface roughness R(a) = 0.062 mm) and the roughest surface occurred with the heavily sandblasted sample (surface roughness R(a) = 0.488 mm). The roughness of the concrete floor samples was related to the mean and peak contact pressures that can occur in a laboratory test bench between floor and bovine claw. It was found that the claw itself has approximately 2 times more effect on these contact pressures than the surface roughness. Peak pressures found were high enough (up to 111 MPa) to cause damage to the bovine claw sole horn. The strains occurring in the horn wall were measured and related to the floor-finishing method and the load. Strain gauge measurements indicated that it is difficult to predict what kind of deformation of the claw wall will occur at a certain location. Different strains will occur for different floor-finishing methods. The corresponding stresses in the horn wall did not exceed the yield stress (14 and 11 MPa for dorsal and abaxial wall horn, respectively).
Effects of relative density and accumulated shear strain on post-liquefaction residual deformation
Directory of Open Access Journals (Sweden)
J. Kim
2013-10-01
Full Text Available The damage caused by liquefaction, which occurs following an earthquake, is usually because of settlement and lateral spreading. Generally, the evaluation of liquefaction has been centered on settlement, that is, residual volumetric strain. However, in actual soil, residual shear and residual volumetric deformations occur simultaneously after an earthquake. Therefore, the simultaneous evaluation of the two phenomena and the clarification of their relationship are likely to evaluate post-liquefaction soil behaviors more accurately. Hence, a quantitative evaluation of post-liquefaction damage will also be possible. In this study, the effects of relative density and accumulated shear strain on post-liquefaction residual deformations were reviewed through a series of lateral constrained-control hollow cylindrical torsion tests under undrained conditions. In order to identify the relationship between residual shear and residual volumetric strains, this study proposed a new test method that integrates monotonic loading after cyclic loading, and K0-drain after cyclic loading – in other words, the combination of cyclic loading, monotonic loading, and the K0 drain. In addition, a control that maintained the lateral constrained condition across all the processes of consolidation, cyclic loading, monotonic loading, and drainage was used to reproduce the anisotropy of in situ ground. This lateral constrain control was performed by controlling the axial strain, based on the assumption that under undrained conditions, axial and lateral strains occur simultaneously, and unless axial strain occurs, lateral strain does not occur. The test results confirmed that the recovery of effective stresses, which occur during monotonic loading and drainage after cyclic loading, respectively, result from mutually different structural restoration characteristics. In addition, in the ranges of 40–60% relative density and 50–100% accumulated shear strain, relative
Hartmann, Peter
2015-10-01
The design of high-quality imaging lenses continues to strive for the best color trueness over wider and wider wavelength ranges such as for multiwavelength fluorescence microscopy or hyperspectral imaging. Glasses suitable for sharp images at more than two wavelengths must differ in their dispersion from the classical crown and flint glass types, which gather along a straight line in a plot of the relative partial dispersion against the Abbe number. Glasses suitable for multicolor correction can be recognized by a considerable deviation of their relative partial dispersion from this normal line. Originally, the normal lines for different relative partial dispersions were defined by using the SCHOTT glass types K7 and F2. Today's data sheets of all glass manufacturers contain numerical values for deviations of relative partial dispersions from the normal lines. A comparison of almost identical glasses shows differences between these deviations being too large, obviously coming from different versions of K7 and F2 dispersion curves used. For preselection in designs and for direct comparison of glass types, it is necessary to agree on common dispersion curves each for K7 and for F2 in order to obtain really comparable values for deviations of the relative partial dispersion from the normal line.
Directory of Open Access Journals (Sweden)
Loredana TANASIE
2012-12-01
Full Text Available In this paper the zeros of some dispersion relations apperaring in sound attenuation problems in circular lined ducts, carrying a gas flow, are investigated numerically. To find the values of frequencies for which the dispersion relations vanish is not easy at all. That is beacause these relations contain the solution of an initial value problem which depends on the unknown frequency and can not be found explicitly. In order to overcome this difficulty we consider approximate dispersion relations, obtained by replacing in the shear flow the solution of the initial value problem by its Taylor’s polynomial approximate. For numerical computations typical aeronautical examples are considered.
Institute of Scientific and Technical Information of China (English)
2008-01-01
Earthquake,as disastrous events in geological history,can be recorded as soft-sediment deformation.In the Palaeogene of the East China Sea shelf,the soft-sediment deformation related to earthquake event is recognized as seismic micro-fractures,micro-corrugated laminations,liquefied veins,'vibrated liquefied layers',deformed cross laminations and convolute laminations,load structures,flame structures,brecciation,slump structures and seismodisconformity.There exists a lateral continuum,the wide spatial distribution and the local vertical continuous sequences of seismites including slump,liquefaction and brecciation.In the Palaeogene of East China Sea shelf,where typical soft-sediment deformation structures were developed,clastic deposits of tidal-flat,delta and river facies are the main background deposits of Middle-Upper Eocene Pinghu Formation and Oligocene Huagang Formation.This succession also records diagnostic marks of event deposits and basinal tectonic activities in the form of seismites.
Institute of Scientific and Technical Information of China (English)
LU Hongbo; ZHANG Yuxu; ZHANG Qiling; XIAO Jiafei
2006-01-01
The authors introduced two kinds of newly found soft-sediment deformation-syn-sedimentary extension structure and syn-sedimentary compression structure, and discuss their origins and constraints on basin tectonic evolution. One representative of the syn-sedimentary extension structure is syn-sedimentary boudinage structure, while the typical example of the syn-sedimentary compression structure is compression sand pillows or compression wrinkles. The former shows NW-SE-trending contemporaneous extension events related to earthquakes in the rift basin near a famous Fe-Nb-REE deposit in northern China during the Early Paleozoic (or Mesoproterozoic as proposed by some researches), while the latter indicates NE-SW-trending contemporaneous compression activities related to earthquakes in the Middle Triassic in the Nanpanjiang remnant basin covering south Guizhou, northwestern Guangxi and eastern Yunnan in southwestern China. The syn-sedimentary boudinage structure was found in an earthquake slump block in the lower part of the Early Paleozoic Sailinhudong Group, 20 km to the southeast of Bayan Obo, Inner Mongolia, north of China. The slump block is composed of two kinds of very thin layers-pale-gray micrite (microcrystalline limestone) of 1-2 cm thick interbedded with gray muddy micrite layers with the similar thickness. Almost every thin muddy micrite layer was cut into imbricate blocks or boudins by abundant tiny contemporaneous faults, while the interbedded micrite remain in continuity. Boudins form as a response to layer-parallel extension (and/or layer-perpendicular flattening) of stiff layers enveloped top and bottom by mechanically soft layers. In this case, the imbricate blocks cut by the tiny contemporaneous faults are the result of abrupt horizontal extension of the crust in the SE-NW direction accompanied with earthquakes. Thus, the rock block is, in fact, a kind of seismites. The syn-sedimentary boudins indicate that there was at least a strong earthquake
Tidal deformability and I-Love-Q relations for gravastars with polytropic thin shells
Uchikata, Nami; Pani, Paolo
2016-01-01
The moment of inertia, the spin-induced quadrupole moment, and the tidal Love number of neutron-star and quark-star models are related through some relations which depend only mildly on the stellar equation of state. These "I-Love-Q" relations have important implications for astrophysics and gravitational-wave astronomy. An interesting problem is whether similar relations hold for other compact objects and how they approach the black-hole limit. To answer these questions, here we investigate the deformation properties of a large class of thin-shell gravastars, which are exotic compact objects that do not possess an event horizon nor a spacetime singularity. Working in a small-spin and small-tidal field expansion, we calculate the moment of inertia, the quadrupole moment, and the (quadrupolar electric) tidal Love number of gravastars with a polytropic thin shell. The I-Love-Q relations of a thin-shell gravastar are drastically different from those of an ordinary neutron star. The Love number and quadrupole mom...
Diffusion related isotopic fractionation effects with one-dimensional advective–dispersive transport
Energy Technology Data Exchange (ETDEWEB)
Xu, Bruce S. [Civil Engineering Department, University of Toronto, 35 St George Street, Toronto, ON M5S 1A4 (Canada); Lollar, Barbara Sherwood [Earth Sciences Department, University of Toronto, 22 Russell Street, Toronto, ON M5S 3B1 (Canada); Passeport, Elodie [Civil Engineering Department, University of Toronto, 35 St George Street, Toronto, ON M5S 1A4 (Canada); Chemical Engineering and Applied Chemistry Department, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 (Canada); Sleep, Brent E., E-mail: sleep@ecf.utoronto.ca [Civil Engineering Department, University of Toronto, 35 St George Street, Toronto, ON M5S 1A4 (Canada)
2016-04-15
Aqueous phase diffusion-related isotope fractionation (DRIF) for carbon isotopes was investigated for common groundwater contaminants in systems in which transport could be considered to be one-dimensional. This paper focuses not only on theoretically observable DRIF effects in these systems but introduces the important concept of constraining “observable” DRIF based on constraints imposed by the scale of measurements in the field, and on standard limits of detection and analytical uncertainty. Specifically, constraints for the detection of DRIF were determined in terms of the diffusive fractionation factor, the initial concentration of contaminants (C{sub 0}), the method detection limit (MDL) for isotopic analysis, the transport time, and the ratio of the longitudinal mechanical dispersion coefficient to effective molecular diffusion coefficient (D{sub mech}/D{sub eff}). The results allow a determination of field conditions under which DRIF may be an important factor in the use of stable carbon isotope measurements for evaluation of contaminant transport and transformation for one-dimensional advective–dispersive transport. This study demonstrates that for diffusion-dominated transport of BTEX, MTBE, and chlorinated ethenes, DRIF effects are only detectable for the smaller molar mass compounds such as vinyl chloride for C{sub 0}/MDL ratios of 50 or higher. Much larger C{sub 0}/MDL ratios, corresponding to higher source concentrations or lower detection limits, are necessary for DRIF to be detectable for the higher molar mass compounds. The distance over which DRIF is observable for VC is small (less than 1 m) for a relatively young diffusive plume (< 100 years), and DRIF will not easily be detected by using the conventional sampling approach with “typical” well spacing (at least several meters). With contaminant transport by advection, mechanical dispersion, and molecular diffusion this study suggests that in field sites where D{sub mech}/D{sub eff} is
Energy Technology Data Exchange (ETDEWEB)
Chen, S.R.; Gray, G.T. III; Bingert, S.R. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.
1996-05-01
Tantalum and its alloys have received increased interest as a model bcc metal and for defense-related applications. The stress-strain behavior of several tantalums, possessing varied compositions and manufacturing histories, and tantalum alloyed with tungsten, was investigated as a function of temperature from {minus}196 C to 1,000 C, and strain rate from 10{sup {minus}3} s{sup {minus}1} to 8,000 s{sup {minus}1}. The yield stress for all the Ta-materials was found to be sensitive to the test temperature, the impurity and solute contents; however, the strain hardening remained very similar for various ``pure`` tantalums but increased with alloying. Powder-metallurgy (P/M) tantalum with various levels of oxygen content produced via different processing paths was also investigated. Similar mechanical properties compared to conventionally processed tantalums were achieved in the P/M Ta. This data suggests that the frequently observed inhomogeneities in the mechanical behavior of tantalum inherited from conventional processes can be overcome. Constitutive relations based upon the Johnson-Cook, the Zerilli-Armstrong, and the Mechanical Threshold Stress models were evaluated for all the Ta-based materials. Parameters were also fit for these models to a tantalum-bar material. Flow stresses of a Ta bar stock subjected to a large-strain deformation of {var_epsilon} = 1.85 via multiple upset forging were obtained. The capabilities and limitations of each model for large-strain applications are examined. The deformation mechanisms controlling high-rate plasticity in tantalum are revisited.
Dispersion relation for hadronic light-by-light scattering: theoretical foundations
Colangelo, Gilberto; Procura, Massimiliano; Stoffer, Peter
2015-01-01
In this paper we make a further step towards a dispersive description of the hadronic light-by-light (HLbL) tensor, which should ultimately lead to a data-driven evaluation of its contribution to $(g-2)_\\mu$. We first provide a Lorentz decomposition of the HLbL tensor performed according to the general recipe by Bardeen, Tung, and Tarrach, generalizing and extending our previous approach, which was constructed in terms of a basis of helicity amplitudes. Such a tensor decomposition has several advantages: the role of gauge invariance and crossing symmetry becomes fully transparent; the scalar coefficient functions are free of kinematic singularities and zeros, and thus fulfill a Mandelstam double-dispersive representation; and the explicit relation for the HLbL contribution to $(g-2)_\\mu$ in terms of the coefficient functions simplifies substantially. We demonstrate explicitly that the dispersive approach defines both the pion-pole and the pion-loop contribution unambiguously and in a model-independent way. Th...
Black Hole Radiation with Modified Dispersion Relation in Tunneling Paradigm: Free-fall Frame
Wang, Peng; Ying, Shuxuan
2015-01-01
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass $m_{p}$. The corrections to the Hawking temperature are calculated for massive and charged particles to $\\mathcal{O}\\left( m_{p}^{-2}\\right) $ and neutral and massless particles with $\\lambda=0$ to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is...
Black hole radiation with modified dispersion relation in tunneling paradigm: free-fall frame
Energy Technology Data Exchange (ETDEWEB)
Wang, Peng; Yang, Haitang; Ying, Shuxuan [Sichuan University, Center for Theoretical Physics, College of Physical Science and Technology, Chengdu (China)
2016-01-15
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study the effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass m{sub p}. The corrections to the Hawking temperature are calculated for massive and charged particles to O(m{sub p}{sup -2}) and neutral and massless particles with λ = 0 to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole and a 2D one. Finally, the luminosity of a Schwarzschild black hole is calculated by using the geometric optics approximation. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Shinozuka, K.; Tamura, M.; Esaka, H. [National Defense Academy, Dept. MS and E, Kanagawa (Japan); Shiba, K.; Nakamura, K. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan)
2007-07-01
Full text of publication follows: Oxide dispersion strengthened (ODS) steel is a promising candidate for fusion reactor material because of excellent mechanical properties. However, the ODS steel exhibits some defects, such as mechanical anisotropy and little elongation . To reveal details of these defects, we investigated correlations between mechanical and microstructural behavior of ODS ferritic steels during creep deformation at high temperature. The materials used in this study are two kinds of hot rolled ODS steels: Fe-8Cr-2W-0.2V-0.1Ta-0.2Ti-0.4Y{sub 2}O{sub 3} (J1) and Fe-8Cr-1W-0.2Ti-0.4Y{sub 2}O{sub 3} (J2). Creep tests was carried out on specimens sampling along both the rolling direction and the cross direction at 670, 700 and 730 deg. C. Microstructural analyses were made on the normalized and tempered condition by using OM, SEM, TEM and XRD. Creep ruptured and interrupted specimens were also investigated. Both J1 and J2 existed two phases, namely martensite and {delta}-ferrite which was elongated in the rolling direction. Y-Ti complex oxide particles were finely dispersed in martensite and {delta}- ferrite phases. Results of creep tests indicated that the time-to-rupture of specimens of J1 were much longer than J2, and the time-to-rupture of specimens sampling along the rolling direction were longer than cross direction. Accordingly, J1 sampling along hot rolling direction was the strongest, for instance, the time-to-rupture was 11400 h at 700 deg. C and 162 MPa. All specimens indicated that elongation was less than 1.3 % and the rupture occurred at steady state creep region from creep curves. Internal cracks were propagated in martensite phase along elongated {delta}-ferrite phase in the direction of hot rolling. On the other hand, {delta}-ferrite phases seemed to prevent combining cracks. These results suggest that elongated {delta}-ferrite and internal clacks in martensite strongly affect on the anisotropy and little elongation of creep. (authors)
Relative dispersion of clustered drifters in a small micro-tidal estuary
Suara, Kabir; Chanson, Hubert; Borgas, Michael; Brown, Richard J.
2017-07-01
Small tide-dominated estuaries are affected by large scale flow structures which combine with the underlying bed generated smaller scale turbulence to significantly increase the magnitude of horizontal diffusivity. Field estimates of horizontal diffusivity and its associated scales are however rare due to limitations in instrumentation. Data from multiple deployments of low and high resolution clusters of GPS-drifters are used to examine the dynamics of a surface flow in a small micro-tidal estuary through relative dispersion analyses. During the field study, cluster diffusivity, which combines both large- and small-scale processes ranged between, 0.01 and 3.01 m2/s for spreading clusters and, -0.06 and -4.2 m2/s for contracting clusters. Pair-particle dispersion, Dp2, was scale dependent and grew as Dp2 ∼ t1.83 in streamwise and Dp2 ∼ t0.8 in cross-stream directions. At small separation scale, pair-particle (d law and became weaker as separation scale increases. Pair-particle diffusivity was described as Kp ∼ d1.01 and Kp ∼ d0.85 in the streamwise and cross-stream directions, respectively for separation scales ranging from 0.1 to 10 m. Two methods were used to identify the mechanism responsible for dispersion within the channel. The results clearly revealed the importance of strain fields (stretching and shearing) in the spreading of particles within a small micro-tidal channel. The work provided input for modelling dispersion of passive particle in shallow micro-tidal estuaries where these were not previously experimentally studied.
Morales, J; Fonseca, F; Morales, John; Quimbay, Carlos; Fonseca, Frank
1999-01-01
We calculate the fermionic dispersion relations in the minimal standard model at finite temperature in presence of non-vanishing chemical potentials due to the CP-asymmetric fermionic background. The dispersion relations are calculated for a vacuum expectation value of the Higgs field equal to zero (unbroken electroweak symmetry). The calculation is performed in the real time formalism of the thermal field theory at one-loop order in a general $\\xi$ gauge. The fermionic self-energy is calculated at leading order in temperature and chemical potential and this fact permits us to obtain gauge invariant analytical expressions for the dispersion relations.
Morphological Tuning of the Plasmon Dispersion Relation in Dielectric-Loaded Nanofiber Waveguides
DEFF Research Database (Denmark)
Leißner, Till; Lemke, Christoph; Fiutowski, Jacek
2013-01-01
in a waveguide. This Letter reports on the measurement of the real part of the surface plasmon polariton dispersion relation in the near infrared spectral regime for individual nanoscale plasmonic waveguides, which were formed by deposition of para-hexaphenylene (p-6P) based nanofibers on top of a gold film....... A detailed structural characterization of the nanofibers provides accurate information on the dimensions of the investigated waveguides and enables us to quantify the effect of mode confinement by comparison with experimental results from continuous p-6P films and calculations based on the effective index...
Disordered locality and Lorentz dispersion relations: an explicit model of quantum foam
Caravelli, F
2012-01-01
Using the framework of Quantum Graphity, we construct an explicit model of a quantum foam, a quantum spacetime with spatial wormholes. The states depend on two parameters: the minimal size of the wormholes and their density with respect to this length. Macroscopic Lorentz invariance requires that the quantum superposition of spacetimes is suppressed by the length of these wormholes. We parametrize this suppression by the distribution of wormhole lengths in the quantum foam. We discuss the general case and then analyze two specific natural wormhole distributions. Corrections to the Lorentz dispersion relations are calculated using techniques developed in previous work.
Light-induced nonlinear effects on dispersion relation of ultracold Bose gas
Institute of Scientific and Technical Information of China (English)
胡正峰; 杜春光; 李师群
2003-01-01
We have investigated the optical properties of A-configuration ultracold dense Bose gas interacting with two laser pulses, which usually result in electromagnetically induced transparency. With the nonrelativistic quantum electrodynamics and taking into account the atomic dipole-dipole interaction and local field effect, we have derived the Maxwell-Bloch equations of the system. The dispersion relation of an ultracold Bose gas has been obtained and the light-induced nonlinear effects have been analysed. The light-induced nonlinear effects are different from the effects induced by two-body collision of Bose-Einstein condensation atoms which have a frequency shift of transparent window.
Light—induced nonlinear effects of dispersion relation of ultracold Bose gas
Institute of Scientific and Technical Information of China (English)
HuZheng-Feng; DuChunGuang; LiShi-Qun
2003-01-01
We have investigated the optical properties of A-configuration ultracold dense Bose gas interacting with two laser pulses, which usually result in electromagnetically induced transparency. With the nonrelativistic quantum electrodynamics and taking into account the atomic dipole-dipole interaction and local field effect, we have derived the Maxwell-Bloch equations of the system. The dispersion relation of an ultracold Bose gas has been obtained and the light-induced nonlinear effects have been analysed. The light-induced nonlinear effects are different from the effects induced by two-body collision of Bose-Einstein condensation atoms which have a frequency shift of transparent window.
Near-field heat transfer between graphene monolayers: Dispersion relation and parametric analysis
Yin, Ge; Yang, Jiang; Ma, Yungui
2016-12-01
Plasmon polaritons in graphene can enhance near-field heat transfer. In this work, we give a complete parametric analysis on the near-field heat transfer between two graphene monolayers that allows transfer efficiencies several orders-of-magnitude larger than blackbody radiation. Influences of major parameters are conclusively clarified from the changes of the interlayer supermode coupling and their dispersion relations. The method to maximize the near-field heat flux is discussed. The generalized Stefan-Boltzmann formula is proposed to describe the near-field heat transfer dominated by evanescent wave tunneling. Our results are of practical significance in guiding the design of thermal management systems.
Dispersion Relation of a Surface Wave at a Rough Metal-Air Interface
Kotelnikov, Igor
2016-01-01
We derived a dispersion relation of a surface wave at a rough metal-air interface. In contrast to previous publications, we assumed that an intrinsic surface impedance due to a finite electric conductivity of the metal can be of the same order as the roughness-induced impedance. We then applied our results to the analysis of a long-standing problem of the discrepancy between the experimental data on the propagation of surface waves in the terahertz range of frequencies and the classical Drude theory.
An Analysis of the New LHC Data through the Dispersion Relations
Selyugin, O V
2016-01-01
We analyse the tension between the (indirect) measurements of the total cross section, and show the impact of various assumptions on the extraction of the parameters from the elastic scattering amplitude, with a special attention to the total cross section. In particular, the determination of the phase of the elastic scattering amplitude will play an important role, and we shall study it via dispersion relations. We shall also examine the origin of the dependence on momentum transfer of the slopes of the different parts of the scattering amplitude in different models. We shall also give the results of another similar analysis based on a Regge-trajectory approach for the hadron scattering amplitude.
Shinton, I
2008-01-01
The globalised cascaded scattering matrix technique is a well proven, practical method that can be used to simulate large accelerating RF structures in which realistic fabrication errors to be incorporated in an efficient manner without the necessity to re-mesh the entire geometry. The globalised scattering matrix (GMS) technique allows one to obtain the scattering matrix for a structure. The method allows rapid e.m. field calculations to be obtained. Results are presented on monopole mode fields and dispersion relations calculated from direct and analytical methods. Analytical approximate results are also presented for the equivalent shunt susceptance of an iris loaded structure.
DETERMINANTS OF RED-BLOOD-CELL DEFORMABILITY IN RELATION TO CELL AGE
BOSCH, FH; WERRE, JM; ROERDINKHOLDERSTOELWINDER, B; HULS, T; WILLEKENS, FLA; WICHERS, G; HALIE, MR
1994-01-01
Red blood cell (RBC) deformability was determined with an ektacytometer in fractions separated on the basis of differences in cell volume or density. Deformability was measured with ektacytometry (rpm-scan and osmo-scan). We studied three groups of RBC fractions:l. By counterflow centrifugation we o
Analysis of related factors on the deformity correction of balloon kyphoplasty.
Xu, C; Liu, H-X; Xu, H-Z
2014-01-01
Balloon kyphoplasty is a minimally invasive surgical approach for treating vertebral compression fractures, including osteoporotic vertebral compression fractures. The purpose of this study was to determine the effect of balloon inflation and postural reduction on balloon kyphoplasty for the deformity correction of vertebral compression fractures and to explore the correlative factors affecting the deformity correction. A retrospective study of 72 patients (75 levels) who had undergone balloon kyphoplasty was conducted. Imaging data and clinical features were collected and analyzed. Independent-samples t test analysis was used to find the possible factors affecting deformity correction. Postural correction in the overextending position significantly increased anterior middle vertebral height, kyphotic angle, and Cobb angle (each P postural reduction and balloon dilation (each P > .05). The improvement on the Visual Analog Scale was notable (P correction. The deformity correction was attributed to postural reduction with cement strengthening. The most significant factors affecting deformity correction were the fracture type and bone cement injected volume.
Institute of Scientific and Technical Information of China (English)
HUANG Fu-qiong; CHEN Yong; BAI Chang-qing; ZHANG Jing; YAN Rui; YANG Ming-bo; LAN Cong-xin; ZHANG Xiao-dong; JIANG Zai-sen
2005-01-01
We discuss the influence of precipitation and groundwater on the deformation behavior of the Babaoshan fault of Beijing by using long-term observation data from Dahuichang station during 1970～2003. The results show that a)the pore pressure on fault zone as well as the fault deformation behavior exhibited periodically variation as precipitation changed steadily and periodically; b) the periodicity of the pore pressure of fault zones disappeared and the manner of fault deformation behavior changed when precipitation was small and/or was in aberrance. This implies that rainfall plays a key role in fault deformation behavior through changing the pore pressure of fault zones. Combining the existing results about the Babaoshan fault, it is concluded that precipitation and groundwater may adjust the stress/strain field by controlling the deformation behavior of the fault, which can provide direct observation evidence for the interaction of fluid and solid in shallow crust of the Earth.
Directory of Open Access Journals (Sweden)
Simon Hallstan
2013-05-01
Full Text Available Species distribution modeling is used in applied ecology; for example in predicting the consequences of global change. However, questions still remain about the robustness of model predictions. Here we estimate effects of landscape spatial configuration and organism flight ability—factors related to dispersal—on the accuracy of species distribution models. Distribution models were developed for 129 phytoplankton taxa, 164 littoral invertebrate taxa and 44 profundal invertebrate taxa sampled in 105 Swedish lakes, using six different modeling techniques (generalized linear models (GLM, multivariate adaptive regression splines (MARS, classification tree analysis (CTA, mixture discriminant analysis (MDA, generalized boosting models (GBM and random forests (RF. Model accuracy was not affected by dispersal ability (i.e., invertebrate flight ability, but the accuracy of phytoplankton assemblage predictions and, to a lesser extent, littoral invertebrate assemblages were related to ecosystem size and connectivity. Although no general pattern across species or spatial configuration was evident from our study, we recommend that dispersal and spatial configuration of ecosystems should be considered when developing species distribution models.
Muñoz Mateo, A.; Brand, J.
2015-12-01
We analyse the dynamical properties of three-dimensional solitary waves in cylindrically trapped Bose-Einstein condensates. Families of solitary waves bifurcate from the planar dark soliton and include the solitonic vortex, the vortex ring and more complex structures of intersecting vortex lines known collectively as Chladni solitons. The particle-like dynamics of these guided solitary waves provides potentially profitable features for their implementation in atomtronic circuits, and play a key role in the generation of metastable loop currents. Based on the time-dependent Gross-Pitaevskii equation we calculate the dispersion relations of moving solitary waves and their modes of dynamical instability. The dispersion relations reveal a complex crossing and bifurcation scenario. For stationary structures we find that for μ /{\\hslash }{ω }\\perp \\gt 2.65 the solitonic vortex is the only stable solitary wave. More complex Chladni solitons still have weaker instabilities than planar dark solitons and may be seen as transient structures in experiments. Fully time-dependent simulations illustrate typical decay scenarios, which may result in the generation of multiple separated solitonic vortices.
Wilson, Susan; Rooney, Philip J; Caldwell, Caroline; Kay, Scott T; Collins, Chris A; McCarthy, Ian G; Romer, A Kathy; Bermeo-Hernandez, Alberto; Bernstein, Rebecca; da Costa, Luiz; Gifford, Daniel; Hollowood, Devon; Hoyle, Ben; Jeltema, Tesla; Liddle, Andrew R; Maia, Marcio A G; Mann, Robert G; Mayers, Julian A; Mehrtens, Nicola; Miller, Christopher J; Nichol, Robert C; Ogando, Ricardo; Sahlén, Martin; Stahl, Benjamin; Stott, John P; Thomas, Peter A; Viana, Pedro T P; Wilcox, Harry
2015-01-01
We measure the evolution of the velocity dispersion--temperature ($\\sigma_{\\rm v}$--$T_{\\rm X}$) relation up to $z = 1$ using a sample of 38 galaxy clusters drawn from the \\textit{XMM} Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 $z > 0.5$ clusters observed with the GMOS instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalisation is slightly negative, but not significantly different from zero ($\\sigma_{\\rm v} \\propto T^{0.86 \\pm 0.14} E(z)^{-0.37 \\pm 0.33}$). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen from the data suggests that the feedback does not significantly heat the gas, a result that...
Huang, N. E.; Tung, C.-C.
1977-01-01
The influence of the directional distribution of wave energy on the dispersion relation is calculated numerically using various directional wave spectrum models. The results indicate that the dispersion relation varies both as a function of the directional energy distribution and the direction of propagation of the wave component under consideration. Furthermore, both the mean deviation and the random scatter from the linear approximation increase as the energy spreading decreases. Limited observational data are compared with the theoretical results. The agreement is favorable.
Are Ring Current Ions Lost in Electromagnetic Ion Cyclotron Wave Dispersion Relation?
Khazanov, G. V.; Gamayunov, K. V.
2006-01-01
Electromagnetic ion cyclotron (EMIC) waves are widely observed in the inner and outer magnetosphere, at geostationary orbit, at high latitudes along the plasmapause, and at the ionospheric altitudes. Interaction of the Ring Current (RC) ions and EMIC waves causes ion scattering into the loss cone and leads to decay of the RC, especially during the main phase of storms when the RC decay times of about one hour or less are observed. The oblique EMIC waves damp due to Landau resonance with the thermal plasmaspheric electrons, and subsequent transport of the dissipating wave energy into the ionosphere below causes an ionosphere temperature enhancement. Induced scattering of these waves by the plasmaspheric thermal ions leads to ion temperature enhancement, and forms a so-called hot zone near the plasmapause where the temperature of core plasma ions can reach tens of thousands of degrees. Relativistic electrons in the outer radiation belt also interact well with the EMIC waves, and during the main and/or recovery phases of the storms these electrons can easily be scattered into the loss cone over a time scale from several hours to a day. The plasma density distribution in the magnetosphere and the ion content play a critical role in EMIC wave generation and propagation, but the wave dispersion relation in the known RC-EMIC wave interaction models is assumed to be determined by the thermal plasma distribution only. In these models, the modification of the EMIC wave dispersion relation caused by the RC ions is not taken into account, and the RC ions are only treated as a source of free energy in order to generate EMIC waves. At the same time, the RC ions can dominate the thermal magnetospheric content in the night MLT sector at great L shells during the main and/or recovery storm phase. In this study, using our self-consistent RC-EMIC wave model [Khazanov et al., 2006], we simulate the May 1998 storm in order to quantify the global EMIC wave redistribution caused by
Effect of Ring Current Ions on Electromagnetic Ion Cyclotron Wave Dispersion Relation
Gamayunov, K. V.; Khazanov, G. V.
2006-01-01
Electromagnetic ion cyclotron (EMIC) waves are widely observed in the inner and outer magnetosphere, at geostationary orbit, at high latitudes along the plasmapause, and at the ionospheric altitudes. Interaction of the Ring Current (RC) ions and EMIC waves causes ion scattering into the loss cone and leads to decay of the RC, especially during the main phase of storms when the RC decay times of about one hour or less are observed. The oblique EMIC waves damp due to Landau resonance with the thermal plasmaspheric electrons, and subsequent transport of the dissipating wave energy into the ionosphere below causes an ionosphere temperature enhancement. Induced scattering of these waves by the plasmaspheric thermal ions leads to ion temperature enhancement, and forms a so-called hot zone near the plasmapause where the temperature of core plasma ions can reach tens of thousands of degrees. Relativistic electrons in the outer radiation belt also interact well with the EMIC waves, and during the main and/or recovery phases of the storms these electrons can easily be scattered into the loss cone over a time scale from several hours to a day. The plasma density distribution in the magnetosphere and the ion content play a critical role in EMIC wave generation and propagation, but the wave dispersion relation in the known RC-EMIC wave interaction models is assumed to be determined by the thermal plasma distribution only. In these models, the modification of the EMIC wave dispersion relation caused by the RC ions is not taken into account, and the RC ions are only treated as a source of free energy in order to generate EMIC waves. At the same time, the RC ions can dominate the thermal magnetospheric content in the night MLT sector at great L shells during the main and/or recovery storm phase. In this study, using our self-consistent RC-EMIC wave model [Khazanov et al., 2006], we simulate the May 1998 storm in order to quantify the global EMIC wave redistribution caused by
Black Hole Corrections due to Minimal Length and Modified Dispersion Relation
Tawfik, Abdel Nasser
2015-01-01
The generalized uncertainty principles (GUP) and modified dispersion relations (MDR) are much like two faces for one coin in research for the phenomenology of quantum gravity which apparently plays an important role in estimating the possible modifications of the black hole thermodynamics and the Friedmann equations. We first reproduce the horizon area for different types of black holes and investigate the quantum corrections to Bekenstein-Hawking entropy (entropy-area law). Based on this, we study further thermodynamical quantities and accordingly the modified Friedmann equation in four-dimensional de Sitter-Schwarzschild, Reissner-N\\"{o}rdstrom and Garfinkle-Horowitz-Strominger black holes. In doing this we applied various quantum gravity approaches. The MDR parameter relative to the GUP one is computed and the properties of the black holes are predicted. This should play an important role in estimating response of quantum gravity to the various metric-types of black holes. We found a considerable change in...
Effective matter dispersion relation in quantum covariant Ho\\v{r}ava-Lifshitz gravity
Alexandre, Jean
2015-01-01
We study how quantum fluctuations of the metric in covariant Ho\\v{r}ava-Lifshitz gravity influence the propagation of classical fields (complex scalar and photon). The effective Lorentz-symmetry violation induced by the breaking of 4-dimensional diffeomorphism is then evaluated, by comparing the dressed dispersion relations for both external fields. The constraint of vanishing 3-dimensional Ricci scalar is imposed in the path integral, which therefore explicitly depends on two propagating gravitational degrees of freedom only. Because the matter fields are classical, the present model contains only logarithmic divergences. Furthermore, it imposes the characteristic Ho\\v{r}ava-Lifshitz scale, above which General Relativity is no-longer valid, to be smaller than $10^{10}$ GeV, if one wishes not to violate the current bounds on Lorentz symmetry violation.
Causality and dispersion relations and the role of the S-matrix in the ongoing research
Schroer, Bert
2011-01-01
The adaptation of the Kramers-Kronig dispersion relations to the causal localization structure of QFT led to an important project in particle physics, the only one with a successful closure. The same cannot be said about the subsequent attempts to formulate particle physics as a pure S-matrix project. The feasibility of a pure S-matrix approach are critically analyzed and their serious shortcomings are highlighted. Whereas the conceptual/mathematical demands of renormalized perturbation theory are modest and misunderstandings could easily be corrected, the correct understanding about the origin of the crossing property demands the use of the mathematical theory of modular localization and its relation to the thermal KMS condition. These concepts which combine localization, vacuum polarization and thermal properties under the roof of modular theory will be explained and their use in a new constructive (nonperturbative) approach to QFT will be indicated. The S-matrix still plays a predominant role, but differen...
Bong, Lee-Jin; Neoh, Kok-Boon; Lee, Chow-Yang; Jaal, Zairi
2013-10-01
Paederus fuscipes Curtis, a dermatitis linearis causing agent, has received increasing attention from the public, as it poses a serious health threat after mass dispersal into human-dominated areas. Preventive measures against this insect have so far been unsuccessful partly because of limited knowledge about its dispersal pattern. In this study, the dispersal activity of P. fuscipes was studied at infestation-prone residential buildings in Mainland Penang, Malaysia. The dispersal activity of P. fuscipes showed two peaks, that is, from February to April and August to October. Overall, there was no statistical significant correlation between dispersal and climatic parameters, that is, temperature, relative humidity, total rainfall, at all sampling localities. However, dispersal was primarily caused by human activities in rice fields, which accounted for >60% of the variability in dispersal. Particularly, rice harvesting, including straw burning, and cultivation were the major factors triggering P. fuscipes dispersal. These activities presumably disrupted the habitat and normal activities of P. fuscipes and rendered the rice fields unfavorable refuges. In addition, the beetles might also face food shortages after the disturbance of their prey base in the crop fields. The current study provides a predictive tool of P. fuscipes flight periods to ensure insecticide residual spraying is timed in the infestation-prone residential areas before the onset of infestation.
Directory of Open Access Journals (Sweden)
Stoičkov Viktor
2007-01-01
Full Text Available Introduction QT dispersion (QTd is a measure of non-homogeneous repolarisation of the myocardium and is used as an indicator of arrhythmogenicity. Objective The aim of this study was to assess the relation between QT dispersion, left ventricle systolic function and frequency of ventricular arrhythmias in coronary patients. Method We studied 290 coronary patients, 72 with angina pectoris and 218 after myocardial infarction. Eighty-one coronary patients had frequent and complex ventricular arrhythmias (out of them 19 had ventricular tachycardia and 209 were without arrhythmias or with infrequent ventricular premature contractions (VPC≤10/h. In all patients, QT dispersion, exercise test, 24-hour Holter monitoring and echocardiographic examination were performed. Results Patients with frequent and complex ventricular arrhythmias had significantly higher values of QTd (71.8±25.5 vs 55.6±21.7 ms; p<0.001, corrected QT dispersion (QTdc: 81.3±31.5 vs. 60.3±26.1 ms; p<0.001, left ventricular end-diastolic diameter (LVEDd: 56.2±6.9 vs. 53.4±6.2 mm; p<0.001 and left ventricular end-systolic diameter (LVESd: 39.5±6.2 vs. 36.0±6.3 mm; p<0.001, and significantly lower values of left ventricular ejection fraction (LVEF: 47.7±13.9 vs. 55.9±11.6%; p<0.001 in comparison to those without arrhythmias or with infrequent VPC. Patients with VT had significantly higher values of QTd and QTdc in comparison to other patients with frequent and complex ventricular arrhythmias (83.8±17.1 vs. 69.4±26.2 ms; p<0.02 for QTd; 101.1±23.9:77.6±31.4 ms; p<0.005 for QTdc. There is a significant negative correlation of QTd and QTdc with LVEF, and a significant positive correlation of QTd and QTdc with inside dimensions of the left ventricle, in patients with frequent and complex ventricular arrhythmias. Conclusion The study demonstrated that patients with frequent and complex ventricular arrhythmias had significantly higher values of QTd and QTdc, as well as a higher
Predictions for TOTEM experiment at LHC from integral and derivative dispersion relations
Alkin, A
2010-01-01
Integral and derivative dispersion relations (IDR and DDR) are considered for the proton-proton and antiproton-proton forward scattering amplitudes. A scheme for calculation of the corrections to asymptotic form for the DDR is presented. The data on the total proton-proton and antiproton-proton cross sections as well as the data on the ratios $\\rho $ of real to imaginary part of the forward scattering amplitudes have been analyzed by the IDR and DDR methods within high-energy Regge models. Regge parametrizations of high-energy total cross sections supplemented by the properly calculated low-energy part of the dispersion integral (from the two-proton threshold up to center-of-mass energy 5 GeV) allow to reproduce well the $\\rho $ data at low energies with the only free parameter, subtraction constant. It is shown that three models for the pomeron, simple pole pomeron (with intercept large than unity), tripole pomeron and dipole pomeron (the both with the unit value intercept) lead to practically equivalent des...
Large deformation properties of short doughs: Effect of sucrose in relation to mixing time
Baltsavias, A.; Jurgens, A.; Vliet, T. van
1999-01-01
Large deformation rheological properties of short doughs of various composition prepared under various mixing times were determined in uniaxial compression. Sucrose-syrup doughs exhibited prominent yielding and flow behaviour. Their apparent biaxial extensional viscosity decreased with increasing su
Dombrádi, E.
2012-01-01
Fingerprints of deep-seated, lithospheric deformation are often recognised on the surface, contributing to topographic evolution, drainage organisation and mass transport. Interactions between deep and surface processes were investigated in the Carpathian-Pannonian region. The lithosphere beneath th
On log-sovolev and related inequalities in µ-deformed segal-bargmann spaces
Pita Ruiz Velasco, Claudio de Jesus
2005-01-01
We consider a generalization of the Segal-Bargmann transform, which is a unitary map from a generalized ground state representation onto a generalized Segal-Bargmann space. This generalization is a deformation of quantum theory.
Dombrádi, E.
2012-01-01
Fingerprints of deep-seated, lithospheric deformation are often recognised on the surface, contributing to topographic evolution, drainage organisation and mass transport. Interactions between deep and surface processes were investigated in the Carpathian-Pannonian region. The lithosphere beneath th
Yang, Y.; Özgen, S.
2017-06-01
During the last few decades, CFD (Computational Fluid Dynamics) has developed greatly and has become a more reliable tool for the conceptual phase of aircraft design. This tool is generally combined with an optimization algorithm. In the optimization phase, the need for regenerating the computational mesh might become cumbersome, especially when the number of design parameters is high. For this reason, several mesh generation and deformation techniques have been developed in the past decades. One of the most widely used techniques is the Spring Analogy. There are numerous spring analogy related techniques reported in the literature: linear spring analogy, torsional spring analogy, semitorsional spring analogy, and ball vertex spring analogy. This paper gives the explanation of linear spring analogy method and angle inclusion in the spring analogy method. In the latter case, two di¨erent solution methods are proposed. The best feasible method will later be used for two-dimensional (2D) Airfoil Design Optimization with objective function being to minimize sectional drag for a required lift coe©cient at di¨erent speeds. Design variables used in the optimization include camber and thickness distribution of the airfoil. SU2 CFD is chosen as the §ow solver during the optimization procedure. The optimization is done by using Phoenix ModelCenter Optimization Tool.
Yamada, Kohei; Kizuka, Tokushi
2016-10-01
We observed the tensile deformation of molybdenum (Mo) nanocontacts (NCs) and simultaneously measured their conductance by in situ transmission electron microscopy. During deformation, the contact width decreased from several nanometers to a single-atom size. Mo NCs were thinned via a plastic flowlike deformation process. The process differs from the slip on lattice planes, which is frequently observed in NCs made of noble metals. We plotted histograms of the time-conductance traces measured during the tensile deformation of Mo NCs. In the conductance histograms, we observed peaks at 1.8G0 (G0 = 2e2/h, where e is the electron charge and h is Planck's constant), 3.6G0, and 4.4G0. When the minimum conductance (1.8G0) was measured, the minimum cross-sectional widths of the NCs were 3-7 atoms. These NCs exhibited relaxed structures that formed irregularly after the plastic flowlike deformation occurred in the final stage of the tensile process. We inferred that the aperiodic peaks observed in the conductance histograms originated from irregular variations in the contact areas and atomic configurations of the NCs during the plastic flowlike deformation. Moreover, the conductance value of the single-atom contacts was less than 0.1G0.
Directory of Open Access Journals (Sweden)
Giuseppe Guzzetta
2013-06-01
Full Text Available In order to treat deformation as one of the processes taking place in an irreversible thermodynamic transformation, two main conditions must be satisfied: (1 strain and stress should be defined in such a way that the modification of the symmetry of these tensorial quantities reflects that of the structure of the actual material of which the deforming ideal continuum is the counterpart; and (2 the unique decomposition of the above tensors into the algebraic sum of an isotropic and an anisotropic part with different physical meanings should be recognized. The first condition allows the distinction of the energy balance in irrotational and rotational deformations; the second allows the description of a thermodynamic transformation involving deformation as a function of both process quantities, whose values depend on the specific transition, or path, between two equilibrium states, and of state quantities, which describe equilibrium states of a system quantitatively. One of the main conclusions that can be drawn is that, dealing with deformable materials, the quantities that must appear in thermodynamic equations cannot be tensorial quantities, such as the stress tensor and the infinitesimal or finite strain tensor usually considered in continuum mechanics (or, even worse, their components. The appropriate quantities should be invariants involved by the strain and stress tensors here defined. Another important conclusion is that, from a thermodynamic point of view, the consideration of the measurable volume change occurring in an isothermal deformation does not itself give any meaningful information.
Age-velocity dispersion relations and heating histories in disc galaxies
Aumer, Michael; Binney, James; Schönrich, Ralph
2016-10-01
We analyse the heating of stellar discs by non-axisymmetric structures and giant molecular clouds (GMCs) in N-body simulations of growing disc galaxies. The analysis resolves long-standing discrepancies between models and data by demonstrating the importance of distinguishing between measured age-velocity dispersion relations (AVRs) and the heating histories of the stars that make up the AVR. We fit both AVRs and heating histories with formulae ∝tβ and determine the exponents βR and βz derived from in-plane and vertical AVRs and tilde{β }_R and tilde{β }_z from heating histories. Values of βz are in almost all simulations larger than values of tilde{β }_z, whereas values of βR are similar to or mildly larger than values of tilde{β }_R. Moreover, values of βz (tilde{β }_z) are generally larger than values of βR (tilde{β }_R). The dominant cause of these relations is the decline over the life of the disc in importance of GMCs as heating agents relative to spiral structure and the bar. We examine how age errors and biases in solar neighbourhood surveys influence the measured AVR: they tend to decrease β values by smearing out ages and thus measured dispersions. We compare AVRs and velocity ellipsoid shapes σz/σR from simulations to solar neighbourhood data. We conclude that for the expected disc mass and dark halo structure, combined GMC and spiral/bar heating can explain the AVR of the Galactic thin disc. Strong departures of the disc mass or the dark halo structure from expectation spoil fits to the data.
Mayer, Christian; Jaglin, Xavier H; Cobbs, Lucy V; Bandler, Rachel C; Streicher, Carmen; Cepko, Constance L; Hippenmeyer, Simon; Fishell, Gord
2015-09-02
The medial ganglionic eminence (MGE) gives rise to the majority of mouse forebrain interneurons. Here, we examine the lineage relationship among MGE-derived interneurons using a replication-defective retroviral library containing a highly diverse set of DNA barcodes. Recovering the barcodes from the mature progeny of infected progenitor cells enabled us to unambiguously determine their respective lineal relationship. We found that clonal dispersion occurs across large areas of the brain and is not restricted by anatomical divisions. As such, sibling interneurons can populate the cortex, hippocampus striatum, and globus pallidus. The majority of interneurons appeared to be generated from asymmetric divisions of MGE progenitor cells, followed by symmetric divisions within the subventricular zone. Altogether, our findings uncover that lineage relationships do not appear to determine interneuron allocation to particular regions. As such, it is likely that clonally related interneurons have considerable flexibility as to the particular forebrain circuits to which they can contribute.
Indian Academy of Sciences (India)
Sanjay Chaubey
2007-04-01
In Zn–Bi and Al–Bi systems, both of which belong to monotectic class, dispersion of second phase particles within the matrix have been produced through rapid solidification processing (RSP) route. In order to understand relative catalytic efficiencies of Zn and Al matrices in catalyzing nucleation of Bi particles entrapped in the respective metal matrices, thermal analysis in constant program mode was performed. Thermal analyses revealed that Bi undercools by 132° in Zn matrix and by 157° in Al matrix. Thermodynamic barrier to nucleation (*) for Bi has also been calculated, which is 39.8 kcal/mole and 47.085 kcal/mole, in Zn and Al matrices, respectively at the maximum recorded undercoolings.
Forward dispersion relations and Roy equations in $\\pi\\pi$ scattering
Kaminski, R; Ynduráin, F J
2007-01-01
We review results of an analysis of pipi interactions in S, P and D waves for two-pion effective mass from threshold to about 1.4 GeV. In particular we show a recent improvement of this analysis above the K anti-K threshold using more data for phase shifts and including the S0 wave inelasticity from pipi -> K anti-K. In addition, we have improved the fit to the f2(1270) resonance and used a more flexible P wave parametrization above the K anti-K threshold and included an estimation of the D2 wave inelasticity. The better accuracy thus achieved also required a refinement of the Regge analysis above 1.42 GeV. We have checked that the pipi scattering amplitudes obtained in this approach satisfy remarkably well forward dispersion relations and Roy's equations.
Ganguly, Avijit K
2016-01-01
Dimension-five photon $(\\gamma )$ scalar $(\\phi)$ interaction terms usually appear in the bosonic sector of unified theories of electromagnetism and gravity. In these theories the three propagation eigenstates are different from the three field eigenstates. The dispersion relation in an external magnetic field shows that, for a non- zero energy $(\\omega)$, out of the three propagating eigenstates one has superluminal phase velocity $v_p$. During propagation, another eigenstate undergoes amplification or attenuation, showing signs of an unstable system. The remaining one maintains causality. In this paper, using techniques from optics as well as gravity, we identify the energy $(\\omega)$ interval outside which $v_p \\le c$ for the field eigenstates $|\\gamma_{\\parallel} > $ and $ |\\phi > $, and stability of the system is restored. The behavior of group velocity $v_g$ is also explored in the same context. We conclude by pointing out its possible astrophysical implications.
Modified Dispersion Relations: from Black-Hole Entropy to the Cosmological Constant
Garattini, Remo
2011-01-01
Quantum Field Theory is plagued by divergences in the attempt to calculate physical quantities. Standard techniques of regularization and renormalization are used to keep under control such a problem. In this paper we would like to use a different scheme based on Modified Dispersion Relations (MDR) to remove infinities appearing in one loop approximation in contrast to what happens in conventional approaches. In particular, we apply the MDR regularization to the computation of the entropy of a Schwarzschild black hole from one side and the Zero Point Energy (ZPE) of the graviton from the other side. The graviton ZPE is connected to the cosmological constant by means of of the Wheeler-DeWitt equation.
Modified Dispersion Relations: from Black-Hole Entropy to the Cosmological Constant
Garattini, Remo
2012-07-01
Quantum Field Theory is plagued by divergences in the attempt to calculate physical quantities. Standard techniques of regularization and renormalization are used to keep under control such a problem. In this paper we would like to use a different scheme based on Modified Dispersion Relations (MDR) to remove infinities appearing in one loop approximation in contrast to what happens in conventional approaches. In particular, we apply the MDR regularization to the computation of the entropy of a Schwarzschild black hole from one side and the Zero Point Energy (ZPE) of the graviton from the other side. The graviton ZPE is connected to the cosmological constant by means of of the Wheeler-DeWitt equation.
Effect of magnetic field on the wave dispersion relation in three-dimensional dusty plasma crystals
Energy Technology Data Exchange (ETDEWEB)
Yang Xuefeng [School of Mathematical Sciences, Dalian University of Technology, Dalian 116024 (China); Wang Zhengxiong [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)
2012-07-15
Three-dimensional plasma crystals under microgravity condition are investigated by taking into account an external magnetic field. The wave dispersion relations of dust lattice modes in the body centered cubic (bcc) and the face centered cubic (fcc) plasma crystals are obtained explicitly when the magnetic field is perpendicular to the wave motion. The wave dispersion relations of dust lattice modes in the bcc and fcc plasma crystals are calculated numerically when the magnetic field is in an arbitrary direction. The numerical results show that one longitudinal mode and two transverse modes are coupled due to the Lorentz force in the magnetic field. Moreover, three wave modes, i.e., the high frequency phonon mode, the low frequency phonon mode, and the optical mode, are obtained. The optical mode and at least one phonon mode are hybrid modes. When the magnetic field is neither parallel nor perpendicular to the primitive wave motion, all the three wave modes are hybrid modes and do not have any intersection points. It is also found that with increasing the magnetic field strength, the frequency of the optical mode increases and has a cutoff at the cyclotron frequency of the dust particles in the limit of long wavelength, and the mode mixings for both the optical mode and the high frequency phonon mode increase. The acoustic velocity of the low frequency phonon mode is zero. In addition, the acoustic velocity of the high frequency phonon mode depends on the angle of the magnetic field and the wave motion but does not depend on the magnetic field strength.
Mei, A. B.; Hellman, O.; Schlepütz, C. M.; Rockett, A.; Chiang, T.-C.; Hultman, L.; Petrov, I.; Greene, J. E.
2015-11-01
Synchrotron reflection x-ray thermal diffuse scattering (TDS) measurements, rather than previously reported transmission TDS, are carried out at room temperature and analyzed using a formalism based upon second-order interatomic force constants and long-range Coulomb interactions to obtain quantitative determinations of MgO phonon dispersion relations ℏ ωj (q), phonon densities of states g (ℏ ω ), and isochoric temperature-dependent vibrational heat capacities cv(T ) . We use MgO as a model system for investigating reflection TDS due to its harmonic behavior as well as its mechanical and dynamic stability. Resulting phonon dispersion relations and densities of states are found to be in good agreement with independent reports from inelastic neutron and x-ray scattering experiments. Temperature-dependent isochoric heat capacities cv(T ) , computed within the harmonic approximation from ℏ ωj (q) values, increase with temperature from 0.4 ×10-4eV /atom K at 100 K to 1.4 ×10-4eV /atom K at 200 K and 1.9 ×10-4eV /atom K at 300 K, in excellent agreement with isobaric heat capacity values cp(T ) between 4 and 300 K. We anticipate that the experimental approach developed here will be valuable for determining vibrational properties of heteroepitaxial thin films since the use of grazing-incidence (θ ≲θc , where θc is the density-dependent critical angle) allows selective tuning of x-ray penetration depths to ≲10 nm .
Zhang, Hongmao; Chu, Wei; Zhang, Zhibin
2017-01-01
Little is known about seeding regeneration of cultivated trees compared to wild relatives in areas where seed dispersers are shared. Here, we investigated the differences in seed fates of cultivated walnut (Juglans regia) and wild Manchurian walnut (Juglans mandshurica) trees under rodent predation and dispersal. J. regia seeds have higher nutritional value (large size, mass and kernel mass) and lower mechanical defensiveness (thin endocarp) than J. mandshurica seeds. We tracked seeds of J. regia and J. mandshurica under both enclosure and field conditions to assess differences in competing for seed dispersers of the two co-occurring tree species of the same genus. We found that rodents preferred to harvest, eat and scatter-hoard seeds of J. regia as compared to those of J. mandshurica. Seeds of J. regia were removed and scatter-hoarded faster than those of J. mandshurica. Caches of J. regia were more likely to be rediscovered by rodents than those of J. mandshurica. These results suggest that J. regia showed earlier dispersal fitness but not the ultimate dispersal fitness over J. mandshurica in seeding regeneration under rodent mediation, implying that J. regia has little effect on seeding regeneration of J. mandshurica in the field. The effects of seed traits on seed dispersal fitness may vary at different dispersal stages under animal mediation.
BILATERAL VOLLEYBALL-RELATED DEFORMITY OF THE LITTLE FINGERS: MALLET FINGER AND CLINODACTYLY MIMIC
Directory of Open Access Journals (Sweden)
Mustafa Uslu
2011-03-01
Full Text Available A 14-year-old male high school volleyball player was seen to evaluate right- and left-hand little-finger distal interphalangeal joint deformity and pain. His symptoms began during his second season of competitive play. The distal interphalangeal (DIP joints of the little fingers flexed 20-30°, and a 10-15° valgus deformity was seen at the same joints. Pain was relieved with rest but returned immediately after playing volleyball, so plain radiographs were obtained. The flexion and valgus deformity was obvious on plain radiographs and through a clinical examination. Thus, a bilateral little-finger distal phalanx base epiphysis injury was seen. This injury is characterized by a biplanar Salter Harris physeal injury; type 5 on anteroposterior radiographs and type 2 on lateral plain radiographs. The deformity occurred as a result of competitive volleyball play. To our knowledge, this is the first reported case of a bilateral biplanar physial injury of the base of distal phalanges of the little fingers. Flexion and valgus deformities of DIP joints are a result of repeated micro traumas around the physis.
Institute of Scientific and Technical Information of China (English)
Chen Bing; Jiang Zaisen; Zhao Zhencai
2000-01-01
Using the tendentious accumulation rate of crustal deformation, Dc, the spatial distributionfeatures of deformation across fault in the West of China was studied; the regional patterns ofdeformation accumulation induced by fault activity was established and its seismogenicmeaning was discussed. The types of fault deformation evolution in the time domain and thefeatures of change of large extent anomaly in fault deformation which occurred in 1995 ～ 1996was analyzed comprehensively. It was indicated definitely that 1995～ 1996 is the turningpoint of fault network activity in the West of China since the 1990s; it is closely related to thechange of main seismic active regions in the West of China, i.e., the alternation of strong/weak stages and the change of action range of tectonic stress field in the Qinghai-Tibet blockand its environs; and hence it is of medium- and short-term precursor meaning for the changeof the overall pattern of earthquake activity in the West of China in the year 1996. On such abasis, a preliminary investigation of the mechanical mechanism and block movementbackground was made. We hold that the formation of NE-trending band of Ms6.0earthquakes in 1988～1996 and NW-trending band of Ms5.0 earthquakes in 1997～1999 canprove in mechanics that the West of China is now in a state that the N-S stress weakensrelatively but E-W stress strengthens relatively and predominates.
Cooperation is related to dispersal patterns in Sino-Tibetan populations
Wu, Jia-Jia; Ji, Ting; He, Qiao-Qiao; Du, Juan; Mace, Ruth
2015-01-01
There is growing recognition in both evolutionary biology and anthropology that dispersal is key to establishing patterns of cooperation. However, some models predict that cooperation is more likely to evolve in low dispersal (viscous) populations, while others predict that local competition for resources inhibits cooperation. Sex-biased dispersal and extra-pair mating may also have an effect. Using economic games in Sino-Tibetan populations with strikingly different dispersal patterns, we measure cooperation in 36 villages in southwestern China; we test whether social structure is associated with cooperative behaviour toward those in the neighbourhood. We find that social organization is associated with levels of cooperation in public goods and dictator games and a resource dilemma; people are less cooperative towards other villagers in communities where dispersal by both sexes is low. This supports the view that dispersal for marriage played an important role in the evolution of large-scale cooperation in human society. PMID:26478534
Hung, Ming-Jui; Ko, Ta; Liang, Chung-Yu; Kao, Yu-Cheng
2017-10-01
Although transient reduction in the left ventricular ejection fraction is characteristic of Takotsubo cardiomyopathy, little is known about the time-course changes of myocardial deformation in coronary vasospasm-related Takotsubo cardiomyopathy. We retrospectively analyzed the time-course changes in left ventricle, right ventricle, and left atrium strain values in a patient with coronary vasospasm-related Takotsubo cardiomyopathy. We found that not only left ventricular strain but also left atrial strain was abnormal during acute Takotsubo cardiomyopathy due to coronary vasospasm. Right ventricular free wall strain was normal. Coronary vasospasm-related Takotsubo cardiomyopathy. A serial echocardiographic study. The left ventricular strain was still subnormal despite a normalized left ventricular ejection fraction 2 months later. The left atrial strain was normal when the left ventricular ejection fraction normalized. From this limited experience, it is suggested that echocardiographic myocardial deformation analysis can provide more information than the standard ejection fraction in evaluating myocardial contractile function.
Modeling the dispersion in electromechanically coupled myocardium
Eriksson, Thomas S. E.; Prassl, Anton J.; Plank, Gernot; Holzapfel, Gerhard A.
2014-01-01
SUMMARY We present an approach to model the dispersion of fiber and sheet orientations in the myocardium. By utilizing structure parameters, an existing orthotropic and invariant-based constitutive model developed to describe the passive behavior of the myocardium is augmented. Two dispersion parameters are fitted to experimentally observed angular dispersion data of the myocardial tissue. Computations are performed on a unit myocardium tissue cube and on a slice of the left ventricle indicating that the dispersion parameter has an effect on the myocardial deformation and stress development. The use of fiber dispersions relating to a pathological myocardium had a rather big effect. The final example represents an ellipsoidal model of the left ventricle indicating the influence of fiber and sheet dispersions upon contraction over a cardiac cycle. Although only a minor shift in the pressure–volume (PV) loops between the cases with no dispersions and with fiber and sheet dispersions for a healthy myocardium was observed, a remarkably different behavior is obtained with a fiber dispersion relating to a diseased myocardium. In future simulations, this dispersion model for myocardial tissue may advantageously be used together with models of, for example, growth and remodeling of various cardiac diseases. PMID:23868817
Modeling the dispersion in electromechanically coupled myocardium.
Eriksson, Thomas S E; Prassl, Anton J; Plank, Gernot; Holzapfel, Gerhard A
2013-11-01
We present an approach to model the dispersion of fiber and sheet orientations in the myocardium. By utilizing structure parameters, an existing orthotropic and invariant-based constitutive model developed to describe the passive behavior of the myocardium is augmented. Two dispersion parameters are fitted to experimentally observed angular dispersion data of the myocardial tissue. Computations are performed on a unit myocardium tissue cube and on a slice of the left ventricle indicating that the dispersion parameter has an effect on the myocardial deformation and stress development. The use of fiber dispersions relating to a pathological myocardium had a rather big effect. The final example represents an ellipsoidal model of the left ventricle indicating the influence of fiber and sheet dispersions upon contraction over a cardiac cycle. Although only a minor shift in the pressure-volume (PV) loops between the cases with no dispersions and with fiber and sheet dispersions for a healthy myocardium was observed, a remarkably different behavior is obtained with a fiber dispersion relating to a diseased myocardium. In future simulations, this dispersion model for myocardial tissue may advantageously be used together with models of, for example, growth and remodeling of various cardiac diseases.
Energy Technology Data Exchange (ETDEWEB)
Zhu, Z.W. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Gu, L. [WPI, Advance Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Xie, G.Q. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Zhang, W., E-mail: wzhang@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Inoue, A. [WPI, Advance Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Zhang, H.F., E-mail: hfzhang@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Hu, Z.Q. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)
2011-04-15
The relation between icosahedral short-range ordering (ISRO) and plastic deformation was investigated in Zr{sub 70-x}Nb{sub x}Cu{sub 13.5}Ni{sub 8.5}Al{sub 8} (at.%, x = 0, 2, 4, 6, 7, 8, 10) bulk metallic glasses (BMG). The formation of icosahedral quasicrystal (I-phase) during the annealing process implies that ISRO widely exists in these materials. The degree of ISRO is thermodynamically evaluated to show that ISRO increases with increasing Nb content. Compression tests indicate that BMG with 0-7 at.% Nb possess similar unusual plastic deformability, which is attributed to ISRO-mediated local distribution of free volume (FV) and ISRO prompted deformation-induced crystallization. A proposed core-shell model coupled with transmission electron microscopy analysis demonstrates that the FV is distributed more heterogeneously with increasing ISRO, which is beneficial for multiplying the shear bands. Deformation-induced crystallization is facilitated, owing to the low interfacial energy of the nucleation and growth of the crystals attributed to ISRO in the amorphous matrix, which improves plasticity by consuming energy and the product altering the stress field in the amorphous matrix. Design of new ductile BMG is discussed in these strategies.
Causality and dispersion relations and the role of the S-matrix in the ongoing research
Energy Technology Data Exchange (ETDEWEB)
Schroer, Bert, E-mail: schroer@cbpf.b [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Freie Univ. , Berlin (Germany). Inst. fur Theoretische Physik
2011-07-01
The adaptation of the Kramers-Kronig dispersion relations to the causal localization structure of QFT led to an important project in particle physics, the only one with a successful closure. The same cannot be said about the subsequent attempts to formulate particle physics as a pure S-matrix project. The feasibility of a pure S-matrix approach are critically analyzed and their seri- ous shortcomings are highlighted. Whereas the conceptual/mathematical demands of renormalized perturbation theory are modest and misunderstandings could easily be corrected, the correct understanding about the origin of the crossing property demands the use of the mathematical theory of modular localization and its relation to the thermal KMS condition. These concepts which combine localization, vacuum polarization and thermal properties under the roof of modular theory will be explained and their use in a new constructive (nonperturbative) approach to QFT will be indicated. The S-matrix still plays a predominant role, but different from Heisenberg's and Mandelstam's proposals the new project is not a pure S-matrix approach. (author)
Molinari, Vincenzo
2014-01-01
He-4 is known to become superfluid at very low temperatures. This effect is now generally accepted to be connected with BEC (Bose-Einstein Condensation). The dispersion relation of pressure waves in superfluid He-4 has been determined at 1.1 {\\deg}K by Yarnell et al., and exhibits a non monotonic behaviour - with a maximum and a minimum - usually explained in terms of excitations called rotons, introduced by Landau. In the present work an attempt is made to describe the phenomenon within the bohmian interpretation of QM. To this end, the effects of the intermolecular potential, taken to be essentially of the Lennard-Jones type, are included as a Vlasov-type self-consistent field. A dispersion relation is found, that is in good agreement with Yarnell's curve. Keywords: Bohm potential; Intermolecular potential; Dispersion relation; Superfluid He-4; First sound. PACS: 05.30.Jp; 05.20.Dd; 03.75.Kk; 67.25.dt
Kang, Wol-Rang; Schulze, Andreas; Riechers, Dominik A; Kim, Sang Chul; Park, Daeseong; Smolcic, Vernesa
2013-01-01
To calibrate stellar velocity dispersion measurements from optical and near-IR stellar lines, and to improve the black hole mass (MBH)- stellar velocity dispersion (sigma) relation, we measure stellar velocity dispersions based on high quality H-band spectra for a sample of 31 nearby galaxies, for which dynamical MBH is available in the literature. By comparing velocity dispersions measured from stellar lines in the H-band with those measured from optical stellar lines, we find no significant difference, suggesting that optical and near-IR stellar lines represent the same kinematics and that dust effect is negligible for early-type galaxies. Based on the spatially-resolved rotation and velocity dispersion measurements along the major axis of each galaxy, we find that a rotating stellar disk is present for 80% of galaxies in the sample. For galaxies with a rotation component, velocity dispersions measured from a single aperture spectrum can vary by up to ~20%, depending on the size of the adopted extraction ap...
Wu, Junru; Layman, Christopher; Liu, Jun
2004-02-01
A fundamental mathematical framework for applications of Doublet Mechanics to ultrasound propagation in a discrete material is introduced. A multiscale wave equation, dispersion relation for longitudinal waves, and shear waves are derived. The van Hove singularities and corresponding highest frequency limits for the Mth-order wave equations of longitudinal and shear waves are determined for a widely used microbundle structure. Doublet Mechanics is applied to soft tissue and low-density polyethylene. The experimental dispersion data for soft tissue and low-density polyethylene are compared with results predicted by Doublet Mechanics and an attenuation model based on a Kramers-Kronig relation in classical continuum mechanics.
Institute of Scientific and Technical Information of China (English)
Yujiang Li; Lianwang Chen; Pei Tan; Hong Li
2014-01-01
The channel flow model was gradually being accepted with the more important multidisci-plinary evidences from geology and geophysics, but how the lower crustal flow influenced the surface de-formation quantitatively was unknown. Here, we develop a three-dimensional viscoelastic model to ex-plore the mechanical relations between the lower crustal flow and the surface deformation in western Si-chuan. Based on numerous tests, our results show that the modeled results fit well with the observed GPS data when the lower crust flows faster than the upper crust about 11 mm/a in the rhombic block, which can be useful to understand the possible mechanism of the surface deformation in western Sichuan. Moreover, taking the Xianshuihe fault as an example, we preliminarily analyze the relation between the active fault and stress field, according to the boundary constraints that deduced from the best model. The results show that the maximum shear stress on the Xianshuihe fault zone is mainly located in the fault terminal, intersections and the bend of the fault geometry, the stress level on the northwestern segment that has the high slip rate is relatively high. Additionally, with the reduction of the Young’s modulus in the fault zone, it’s conducive to generate the greater strain distribution, hence forming the high stress level.
Armstrong, R. W.; Balasubramanian, N.
2017-02-01
There is continuing research interest in the development and use of constitutive relations for assistance with description and optimization of higher temperature metal and alloy processing conditions and desired mechanical property performances, particularly in the latter case for nanopolycrystalline materials under creep-type loading deformations. Here, we focus on the plastic flow stress dependence on strain rate, temperature, and especially, on material grain size. Connection is established between, on the one hand, relatively recent thermal-activation-based relations for dislocation motion and, on the other hand, comparative power law expressions.
Thermal mass and dispersion relations of quarks in the deconfined phase of quenched QCD
Kaczmarek, Olaf; Kitazawa, Masakiyo; Soeldner, Wolfgang
2012-01-01
Temporal quark correlation functions are analyzed in quenched lattice QCD for two values of temperature above the critical temperature (Tc) for deconfinement, T=1.5Tc and 3Tc. A two-pole ansatz for the quark spectral function is used to determine the bare quark mass and the momentum dependence of excitation spectra on large lattices of size up to 128^3x16. The dependence of the quark correlator on these parameters as well as the finite volume dependence of the excitation energies are analyzed in detail in order to examine the reliability of our analysis. Our results suggest the existence of quasi-particle peaks in the quark spectrum. We furthermore find evidence that the dispersion relation of the plasmino mode has a minimum at non-zero momentum even in the non-perturbative region near Tc. We also elaborate on the enhancement of the quark correlator near the chiral limit which is observed at T=1.5Tc on about half of the gauge configurations. We attribute this to the presence of near zero-modes of the fermion ...
Average and dispersion of the luminosity-redshift relation in the concordance model
Energy Technology Data Exchange (ETDEWEB)
Ben-Dayan, I. [DESY Hamburg (Germany). Theory Group; Gasperini, M. [Bari Univ. (Italy). Dipt. di Fisica; Istituto Nazionale di Fisica Nucleare, Bari (Italy); Marozzi, G. [College de France, 75 - Paris (France); Geneve Univ. (Switzerland). Dept. de Physique Theorique and CAP; Nugier, F. [Ecole Normale Superieure CNRS, Paris (France). Laboratoire de Physique Theorique; Veneziano, G. [College de France, 75 - Paris (France); CERN, Geneva (Switzerland). Physics Dept.; New York Univ., NY (United States). Dept. of Physics
2013-03-15
Starting from the luminosity-redshift relation recently given up to second order in the Poisson gauge, we calculate the effects of the realistic stochastic background of perturbations of the so-called concordance model on the combined light-cone and ensemble average of various functions of the luminosity distance, and on their variance, as functions of redshift. We apply a gauge-invariant light-cone averaging prescription which is free from infrared and ultraviolet divergences, making our results robust with respect to changes of the corresponding cutoffs. Our main conclusions, in part already anticipated in a recent letter for the case of a perturbation spectrum computed in the linear regime, are that such inhomogeneities not only cannot avoid the need for dark energy, but also cannot prevent, in principle, the determination of its parameters down to an accuracy of order 10{sup -3} - 10{sup -5}, depending on the averaged observable and on the regime considered for the power spectrum. However, taking into account the appropriate corrections arising in the non-linear regime, we predict an irreducible scatter of the data approaching the 10% level which, for limited statistics, will necessarily limit the attainable precision. The predicted dispersion appears to be in good agreement with current observational estimates of the distance-modulus variance due to Doppler and lensing effects (at low and high redshifts, respectively), and represents a challenge for future precision measurements.
Directory of Open Access Journals (Sweden)
Marilena Pannone
2013-01-01
Full Text Available Present work is aimed at the derivation of a simply usable equation for the total flow resistance associated with river bedforms, by a unifying approach allowing for bypassing some of the limiting restrictions usually adopted in similar types of studies. Specifically, we focused on the effect induced by the out-of-phase free surface undulations appearing in presence of sand dunes. The proposed expression, obtained by combining the balance of momentum referred to the control volume whose longitudinal dimension coincides with the dune wavelength and the energy balance integrated between its extreme sections, was tested by comparison with some laboratory experimental measurements available in the literature and referred to steady flow past fixed, variably rough bedforms. In terms of shear stress or friction factor, the proposed theory provides estimates in good agreement with the real data, especially if evaluated against the performances provided by other classical similar approaches. Moreover, when analyzed in terms of hydrodynamic dispersive properties as a function of the skin roughness on the basis of a previously derived analytical solution, the dune-covered beds seem to behave like meandering channels, responsible for a globally enhanced fluid particles longitudinal spreading, with a relatively reduced effect in the presence of less pronounced riverbed modelling.
Forward dispersion relations and Roy equations in {pi}{pi} scattering
Energy Technology Data Exchange (ETDEWEB)
Kaminski, R. [Polish Academy of Sciences, Department of Theoretical Physics Henryk Niewodniczanski Institute of Nuclear Physics, Krakow (Poland); Pelaez, J.R. [Universidad Complutense de Madrid, Departamento de Fisica Teorica, II (Metodos Matematicos), Facultad de Ciencias Fisicas, Madrid (Spain); Yndurain, F.J. [Universidad Autonoma de Madrid, Canto Blanco, Departamento de Fisica Teorica, Madrid (Spain)
2007-03-15
We first review the results of an analysis of {pi}{pi} interactions in S, P and D waves for the two-pion effective mass from threshold to about 1.4 GeV. In particular, we show a recent improvement of this analysis above the K anti K threshold using more data for phase shifts and including the S0-wave inelasticity from {pi}{pi}{yields}K anti K. In addition, we have improved the fit to the f{sub 2}(1270)-resonance and used a more flexible P-wave parametrization above the K anti K threshold and included an estimation of the D2-wave inelasticity. The better accuracy thus achieved also required a refinement of the Regge analysis above 1.42 GeV. Finally, in this work we check that the {pi}{pi} scattering amplitudes obtained in this approach satisfy remarkably well forward dispersion relations and Roy's equations. (orig.)
Fast flavor conversions of supernova neutrinos: Classifying instabilities via dispersion relations
Capozzi, Francesco; Dasgupta, Basudeb; Lisi, Eligio; Marrone, Antonio; Mirizzi, Alessandro
2017-08-01
Supernova neutrinos can exhibit a rich variety of flavor conversion mechanisms. In particular, they can experience "fast" self-induced flavor conversions almost immediately above the core. Very recently, a novel method has been proposed to investigate these phenomena, in terms of the dispersion relation for the complex frequency and wave number (ω ,k ) of disturbances in the mean field of the νeνx flavor coherence. We discuss a systematic approach to such instabilities, originally developed in the context of plasma physics, and based of the time-asymptotic behavior of the Green's function of the system. Instabilities are typically seen to emerge for complex ω and can be further characterized as convective (moving away faster than they spread) and absolute (growing locally), depending on k -dependent features. Stable cases emerge when k (but not ω ) is complex, leading to disturbances damped in space, or when both ω and k are real, corresponding to complete stability. The analytical classification of both unstable and stable modes leads not only to qualitative insights about their features but also to quantitative predictions about the growth rates of instabilities. Representative numerical solutions are discussed in a simple two-beam model of interacting neutrinos. As an application, we argue that supernova and binary neutron star mergers exhibiting a "crossing" in the electron lepton number would lead to an absolute instability in the flavor content of the neutrino gas.
Dispersion Relations and Polarizations of Low-frequency Waves in Two-fluid Plasmas
Zhao, Jinsong
2015-01-01
Analytical expressions for the dispersion relations and polarizations of low-frequency waves in magnetized plasmas based on two-fluid model are obtained. The properties of waves propagating at different angles (to the ambient magnetic field $\\mathbf{B}_{0}$) and \\beta (the ratio of the plasma to magnetic pressures) values are investigated. It is shown that two linearly polarized waves, namely the fast and Alfv\\'{e}n modes in the low-\\beta $\\left( \\beta \\ll 1\\right)$ plasmas, the fast and slow modes in the \\beta \\sim 1 plasmas, and the Alfv\\'{e}n and slow modes in the high-\\beta $\\left( \\beta \\gg 1\\right)$ plasmas, become circularly polarized at the near-parallel (to $\\mathbf{B}_{0}$) propagation. The negative magnetic-helicity of the Alfv\\'{e}n mode occurs only at small or moderate angles in the low-\\beta plasmas, and the ion cross-helicity of the slow mode is nearly the same as that of the Alfv\\'{e}n mode in the high-\\beta plasmas. It also shown the electric polarization $\\delta E_{z}/\\delta E_{y}$ decreases...
Xu, Yanlong
2015-08-01
The coupled mode theory with coupling of diffraction modes and waveguide modes is usually used on the calculations of transmission and reflection coefficients for electromagnetic waves traveling through periodic sub-wavelength structures. In this paper, I extend this method to derive analytical solutions of high-order dispersion relations for shear horizontal (SH) wave propagation in elastic plates with periodic stubs. In the long wavelength regime, the explicit expression is obtained by this theory and derived specially by employing an effective medium. This indicates that the periodical stubs are equivalent to an effective homogenous layer in the long wavelength. Notably, in the short wavelength regime, high-order diffraction modes in the plate and high-order waveguide modes in the stubs are considered with modes coupling to compute the band structures. Numerical results of the coupled mode theory fit pretty well with the results of the finite element method (FEM). In addition, the band structures\\' evolution with the height of the stubs and the thickness of the plate shows clearly that the method can predict well the Bragg band gaps, locally resonant band gaps and high-order symmetric and anti-symmetric thickness-twist modes for the periodically structured plates. © 2015 Elsevier B.V.
Average and dispersion of the luminosity-redshift relation in the concordance model
Energy Technology Data Exchange (ETDEWEB)
Ben-Dayan, I. [DESY Hamburg (Germany). Theory Group; Gasperini, M. [Bari Univ. (Italy). Dipt. di Fisica; Istituto Nazionale di Fisica Nucleare, Bari (Italy); Marozzi, G. [College de France, 75 - Paris (France); Geneve Univ. (Switzerland). Dept. de Physique Theorique and CAP; Nugier, F. [Ecole Normale Superieure CNRS, Paris (France). Laboratoire de Physique Theorique; Veneziano, G. [College de France, 75 - Paris (France); CERN, Geneva (Switzerland). Physics Dept.; New York Univ., NY (United States). Dept. of Physics
2013-03-15
Starting from the luminosity-redshift relation recently given up to second order in the Poisson gauge, we calculate the effects of the realistic stochastic background of perturbations of the so-called concordance model on the combined light-cone and ensemble average of various functions of the luminosity distance, and on their variance, as functions of redshift. We apply a gauge-invariant light-cone averaging prescription which is free from infrared and ultraviolet divergences, making our results robust with respect to changes of the corresponding cutoffs. Our main conclusions, in part already anticipated in a recent letter for the case of a perturbation spectrum computed in the linear regime, are that such inhomogeneities not only cannot avoid the need for dark energy, but also cannot prevent, in principle, the determination of its parameters down to an accuracy of order 10{sup -3} - 10{sup -5}, depending on the averaged observable and on the regime considered for the power spectrum. However, taking into account the appropriate corrections arising in the non-linear regime, we predict an irreducible scatter of the data approaching the 10% level which, for limited statistics, will necessarily limit the attainable precision. The predicted dispersion appears to be in good agreement with current observational estimates of the distance-modulus variance due to Doppler and lensing effects (at low and high redshifts, respectively), and represents a challenge for future precision measurements.
Larecki, Wieslaw; Banach, Zbigniew
2014-01-01
This paper analyzes the propagation of the waves of weak discontinuity in a phonon gas described by the four-moment maximum entropy phonon hydrodynamics involving a nonlinear isotropic phonon dispersion relation. For the considered hyperbolic equations of phonon gas hydrodynamics, the eigenvalue problem is analyzed and the condition of genuine nonlinearity is discussed. The speed of the wave front propagating into the region in thermal equilibrium is first determined in terms of the integral formula dependent on the phonon dispersion relation and subsequently explicitly calculated for the Dubey dispersion-relation model: |k|=ωc-1(1+bω2). The specification of the parameters c and b for sodium fluoride (NaF) and semimetallic bismuth (Bi) then makes it possible to compare the calculated dependence of the wave-front speed on the sample’s temperature with the empirical relations of Coleman and Newman (1988) describing for NaF and Bi the variation of the second-sound speed with temperature. It is demonstrated that the calculated temperature dependence of the wave-front speed resembles the empirical relation and that the parameters c and b obtained from fitting respectively the empirical relation and the original material parameters of Dubey (1973) are of the same order of magnitude, the difference being in the values of the numerical factors. It is also shown that the calculated temperature dependence is in good agreement with the predictions of Hardy and Jaswal’s theory (Hardy and Jaswal, 1971) on second-sound propagation. This suggests that the nonlinearity of a phonon dispersion relation should be taken into account in the theories aiming at the description of the wave-type phonon heat transport and that the Dubey nonlinear isotropic dispersion-relation model can be very useful for this purpose.
Energy Technology Data Exchange (ETDEWEB)
Ben Hamu, G. [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Eliezer, D. [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Institute of Materials Science and Engineering, TU Clausthal (Germany)], E-mail: deliezer@bgu.ac.il; Wagner, L. [Institute of Materials Science and Engineering, TU Clausthal (Germany)
2009-01-22
The quest for ever, higher performance in structural applications has resulted in the outgoing development of new or improved materials with novel crystallographic textures, microstructures, and compositions. However, commercial applicability of such materials depends heavily on the development of economical and robust manufacturing methods. Due to the promise of excellent properties, such as superplasticity, high strength, good ductility, enhanced high cycle fatigue life, and good corrosion resistance, interest has grown in nanostructure bulk materials. Those materials are defined most often as materials exhibiting nanocrystalline grain structures and particle sizes below 100 nm in at least one dimension. In recent years, bulk nanostructure materials processed by methods of severe plastic deformation (SPD) such as equal channel angular extrusion (ECAE) have attracted the growing interest of specialists in materials science. The main object of this research is to compare the microstructural changing and corrosion behavior of magnesium alloy AZ31 after extrusion and severe plastic deformation by ECAE process. The ECAE process can produce intense and uniform deformation by simple shear and provides a convenient procedure for introducing an ultra fine grain size into a material. The samples were prepared by using hot extrusion methods. Hardness and AC and DC polarization tests were carried out on the extruded rods, and the microstructure was examined using optical, electron microscopy (SEM, TEM) and EDS. The results showed that the severe plastic deformation process affected both the microstructure and the corrosion behavior of AZ31 Mg alloy. These results can be explained by the effects of the process on microstructure of AZ31 Mg alloy such as grain size and dislocation density caused by the change in recrystallization behavior.
Yu, Fei; Shi, Xiao-Xiao; Yi, Xian-Feng; Wang, De-Xiang
2013-06-01
An investigation was conducted in a forest farm in the Xiaoxing' an Mountains in autumn, 2009 and 2010 to study the effects of Quercus mongolica acorn quantity and rodent density on the seed dispersal of five tree species (Juglans mandshurica, Pinus koraiensis, Corylus mandshurica, Corylus heterophylla, and Q. mongolica). In the farm, there was an annual change in rodent density. The total capture rate of small rodents in 2009 (31.0%) was significantly higher than that in 2010 (16.7%). The acorn quantity and relative seed abundance (per capita rodent) of Quercus mongolica in 2009 (6.2 +/- 2.1 acorns x m(-2) and 20.0, respectively) were significantly lower than those in 2010 (26.7 +/- 10.2 acorns x m(-2) and 160.0, respectively). In 2009, all the seeds of the five tree species except J. mandshurica were dispersed or eaten in situ, among which, the acorns of Q. mongolica were scatter-hoarded most, and their average dispersal distance was the furthest. In 2010, the seeds of J. mandshurica were scatter-hoarded most, and their average dispersal distance was the furthest. The relative seed abundance of Q. mongolica could be the key factor determining the seed dispersal of the other tree species in the study area.
Schultz, R.A.; Soliva, R.; Fossen, H.; Okubo, C.H.; Reeves, D.M.
2008-01-01
Displacement-length data from faults, joints, veins, igneous dikes, shear deformation bands, and compaction bands define two groups. The first group, having a power-law scaling relation with a slope of n = 1 and therefore a linear dependence of maximum displacement and discontinuity length (Dmax = ??L), comprises faults and shear (non-compactional or non-dilational) deformation bands. These shearing-mode structures, having shearing strains that predominate over volumetric strains across them, grow under conditions of constant driving stress, with the magnitude of near-tip stress on the same order as the rock's yield strength in shear. The second group, having a power-law scaling relation with a slope of n = 0.5 and therefore a dependence of maximum displacement on the square root of discontinuity length (Dmax = ??L0.5), comprises joints, veins, igneous dikes, cataclastic deformation bands, and compaction bands. These opening- and closing-mode structures grow under conditions of constant fracture toughness, implying significant amplification of near-tip stress within a zone of small-scale yielding at the discontinuity tip. Volumetric changes accommodated by grain fragmentation, and thus control of propagation by the rock's fracture toughness, are associated with scaling of predominantly dilational and compactional structures with an exponent of n = 0.5. ?? 2008 Elsevier Ltd.
Grüss, Arnaud; Kaplan, David M; Hart, Deborah R
2011-01-01
Movement of individuals is a critical factor determining the effectiveness of reserve networks. Marine reserves have historically been used for the management of species that are sedentary as adults, and, therefore, larval dispersal has been a major focus of marine-reserve research. The push to use marine reserves for managing pelagic and demersal species poses significant questions regarding their utility for highly-mobile species. Here, a simple conceptual metapopulation model is developed to provide a rigorous comparison of the functioning of reserve networks for populations with different admixtures of larval dispersal and adult movement in a home range. We find that adult movement produces significantly lower persistence than larval dispersal, all other factors being equal. Furthermore, redistribution of harvest effort previously in reserves to remaining fished areas ('fishery squeeze') and fishing along reserve borders ('fishing-the-line') considerably reduce persistence and harvests for populations mobile as adults, while they only marginally changes results for populations with dispersing larvae. Our results also indicate that adult home-range movement and larval dispersal are not simply additive processes, but rather that populations possessing both modes of movement have lower persistence than equivalent populations having the same amount of 'total movement' (sum of larval and adult movement spatial scales) in either larval dispersal or adult movement alone.
Directory of Open Access Journals (Sweden)
Arnaud Grüss
Full Text Available Movement of individuals is a critical factor determining the effectiveness of reserve networks. Marine reserves have historically been used for the management of species that are sedentary as adults, and, therefore, larval dispersal has been a major focus of marine-reserve research. The push to use marine reserves for managing pelagic and demersal species poses significant questions regarding their utility for highly-mobile species. Here, a simple conceptual metapopulation model is developed to provide a rigorous comparison of the functioning of reserve networks for populations with different admixtures of larval dispersal and adult movement in a home range. We find that adult movement produces significantly lower persistence than larval dispersal, all other factors being equal. Furthermore, redistribution of harvest effort previously in reserves to remaining fished areas ('fishery squeeze' and fishing along reserve borders ('fishing-the-line' considerably reduce persistence and harvests for populations mobile as adults, while they only marginally changes results for populations with dispersing larvae. Our results also indicate that adult home-range movement and larval dispersal are not simply additive processes, but rather that populations possessing both modes of movement have lower persistence than equivalent populations having the same amount of 'total movement' (sum of larval and adult movement spatial scales in either larval dispersal or adult movement alone.
Energy Technology Data Exchange (ETDEWEB)
Ditenberg, Ivan A.; Grinyaev, Konstantin V.; Tyumentsev, Alexander N. [National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Siberian Physical-Technical Institute, Tomsk, 634050 (Russian Federation); Smirnov, Ivan V., E-mail: smirnov-iv@bk.ru [National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Siberian Physical-Technical Institute, Tomsk, 634050 (Russian Federation); Pinzhin, Yury P. [National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Tsverova, Anastasiya S. [National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Chernov, Vyacheslav M. [A.A. Bochvar High Technology Research Institute of Inorganic Materials, Moscow, 123098 (Russian Federation)
2015-10-27
Influence of tension temperature on features of plastic deformation and fracture of V–4.23Cr–1.69Zr–7.56W alloy was investigated by scanning and transmission electron microscopy. It is shown that temperature increase leads to activation of the recovery processes, which manifests in the coarsening of microstructure elements, reducing the dislocation density, relaxation of continuous misorientations.
Indian Academy of Sciences (India)
R T Tagiyeva
2004-09-01
Localized magnetic polaritons are investigated in the systems consisting of two magnetic superlattices, coupled by a ferromagnetic contact layer. The general dispersion relation for localized magnetic polaritons are derived in the framework of the electromagnetic wave theory in the Voigt geometry by the `transfer' matrix method. The numerical calculations were carried out for different parameters of the superlattices and contact layer and then discussed.
Verscharen, Daniel
2012-01-01
An ion beam can destabilize Alfv\\'en/ion-cyclotron waves and magnetosonic/whistler waves if the beam speed is sufficiently large. Numerical solutions of the hot-plasma dispersion relation have previously shown that the minimum beam speed required to excite such instabilities is significantly smaller for oblique modes with $\\vec k \\times \\vec B_0\
DEFF Research Database (Denmark)
Sorokin, Vladislav S.; Thomsen, Jon Juel
2016-01-01
The paper deals with analytically predicting the effects of weak nonlinearity on the dispersion relation and frequency band-gaps of a periodic Bernoulli– Euler beam performing bending oscillations. Two cases are considered: (i) large transverse deflections, where nonlinear (true) curvature...
Energy Technology Data Exchange (ETDEWEB)
Tomalak, O. [Johannes Gutenberg Universitaet, Institut fuer Kernphysik, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany); Taras Shevchenko National University of Kyiv, Department of Physics, Kyiv (Ukraine); Vanderhaeghen, M. [Johannes Gutenberg Universitaet, Institut fuer Kernphysik, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany)
2015-02-01
We apply a subtracted dispersion relation formalism with the aim to improve predictions for the two-photon exchange corrections to elastic electron-proton scattering observables at finite momentum transfers. We study the formalism on the elastic contribution, and make a detailed comparison with existing data for unpolarized cross sections as well as polarization transfer observables. (orig.)
The pion-kaon scattering amplitude constrained with forward dispersion relations up to 1.6 GeV
Pelaez, J R
2016-01-01
In this work we provide simple and precise parameterizations of the existing $\\pi K$ scattering data from threshold up to 1.6 GeV, which are constrained to satisfy forward dispersion relations as well as three additional threshold sum rules. We also provide phenomenological values of the threshold parameters and of the resonance poles that appear in elastic scattering.
Wilson, Susan; Rooney, Philip J; Caldwell, Caroline; Kay, Scott T; Collins, Chris A.; McCarthy, Ian G.; Romer, A. Kathy; Bermeo, Alberto; Bernstein, Rebecca; da Costa, Luiz; Gifford, Daniel; Hollowood, Devon; Hoyle, Ben; Jeltema, Tesla; Liddle, Andrew R.
2016-01-01
We measure the evolution of the velocity dispersion-temperature (sigma(v)-T-X) relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes....
Directory of Open Access Journals (Sweden)
Mercedes Okumura
Full Text Available Artificial cranial deformation is a cultural practice that modifies the shape of the skull during the early infancy. It is not related to rites of passage, but to different social status in a group. Therefore, the deformed cranium is an expression of individual affirmation and affiliation to a given social group. Osteological material from Pasamayo (AD 1200-1450, a cemetery in central coast of Peru, was analyzed to test whether individuals presenting different types of cranial deformation (interpreted as a sign of different social status present differences in health status. Three types of cranial deformation were observed and five osteological markers (cribra orbitalia, cranial trauma, antemortem tooth loss, dental caries, and periodontal cavities related to health status were analyzed in 78 crania. No significant differences were found in terms of these osteological markers among females in relation to the different types of cranial deformation. However, males presenting occipital deformation had significantly less caries and periodontal cavities than the others. Moreover, males presenting fronto-lambdoid deformation had more antemortem tooth loss than the other males. Therefore, although different types of cranial deformation can be potentially associated to distinct social status, differences in health status could only be observed in the male sample.
Lin, M; Chu, C C; Lee, H L; Chang, S L; Ohashi, J; Tokunaga, K; Akaza, T; Juji, T
2000-01-01
Taiwan's 9 indigenous tribes (Tsou, Bunun, Paiwan, Rukai, Atayal, Saisiat, Ami, Puyuma, Yami) are highly homogeneous within each tribe, but diversified among the different tribes due to long-term isolation, most probably since Taiwan became an island about 12,000 years ago. Homogeneity of each tribe is evidenced by many HLA-A,B,C alleles having the world's highest ever reported frequencies, e.g. A24 (86.3%), A26 (18.8%), Cw10 (36.8%), Cw7 (66%), Cw8 (32.1%), B13 (27.9%), B62 (37.4%), B75 (18%), B39 (53.5%), B60 (33.3%), and B48 (24%). Also, all of these tribes have HLA class I haplotype frequencies greater than 10%, with A24-Cw7-B39 in Saisiat (44.5%) being the highest, suggesting Taiwan's indigenous tribes are probably the most homogeneous ( the "purest") population in the world. A24-Cw8-B48, A24-Cw10-B60 and A24-Cw9-B61 found common to many Taiwan indigenous tribes, have also been observed in Maori, Papua New Guinea Highlanders, Orochons, Mongolians, Inuit, Japanese, Man, Buryat, Yakut, Tlingit, Tibetans and Thais. These findings suggest Taiwan's indigenous groups are more or less genetically related to both northern and southern Asians. Principal component analysis and the phylogenetic tree (using the neighbor-joining method) showed close relationship between the indigenous groups and Oceanians. This relationship supports the hypothesis that Taiwan was probably on the route of prehistoric Mongoloid dispersals that most likely took place along the coastal lowland of the Asian continent (which is under the sea today). Cultural anthropology also suggests a relationship between Taiwan's indigenous tribes and southern Asians and to a lesser extent, northern Asians. However, the indigenous groups show little genetic relationship to current southern and northern Han Chinese.
Directory of Open Access Journals (Sweden)
André Vitor Fleuri Jardim
2009-10-01
Full Text Available The main selective forces affecting the fruiting strategies are related to the environment in which plants occur. As a savanna, microclimatic conditions should not vary in relation to distance from edge in cerrado sensu stricto fragments. Thus, we postulated that the importance of different dispersal syndromes would not vary towards the fragment core. Our aim was to test in four cerrado sensu stricto fragments in central Brazil whether the absolute density of anemo-, auto-, and zoochorous individuals varied in relation to edge distance. According to results, the absolute density of anemo-and autochorous individuals did not vary, whereas those of zoochorous individuals increased with edge distance, pointing out that there were other factors rather than abiotic conditions shifting zoochorous species to the interior of cerrado sensu stricto fragments.As principais forças seletivas que afetam as estratégias de frutificação estão relacionadas ao ambiente em que as plantas ocorrem. Como fragmentos de cerrado sensu stricto são savânicos, as condições microclimáticas não devem variar em relação à distância da borda. Assim, postulamos que a importância das diferentes síndromes de dispersão não varia da borda ao interior de um fragmento de vegetação. O objetivo deste trabalho foi testar, em quatro fragmentos de cerrado sensu stricto (centro-oeste do Brasil, se a densidade absoluta de indivíduos anemo, auto e zoocóricos variava em função da distância da borda. Segundo nossos resultados, a densidade absoluta de indivíduos anemo e autocóricos não variou significativamente borda em direção ao interior dos fragmentos, enquanto que a dos indivíduos zoocóricos aumentou, indicando que existem outros fatores, que não as condições abióticas, deslocando as espécies zoocóricas para o interior dos fragmentos de cerrado sensu stricto.
Centeno-Salas, F. A.; Carreón-Freyre, D.; Flores-García, W. A.; Gutiérrez-Calderón, R. I.
2015-11-01
In the eastern sector of Mexico City the sub soil consists of high contrasting sequences (lacustrine and volcanic inter bedded deposits) that favor the development of erratic fracturing in the surface causing damage to the urban infrastructure. The high-resolution geophysical prospecting are useful tools for the assessment of ground deformation and fracturing associated with land subsidence phenomena. The GPR method allowed to evaluate the fracture propagation and deformation of vulcano-sedimentary sequences at different depths, the main electrical parameters are directly related with the gravimetric and volumetric water content and therefore with the plasticity of the near surface prospected sequences. The active seismology prospection consisted in a combination of Seismic Refraction (SR) and Multichannel Analysis of Surface Waves (MASW) for the estimation of the velocity of the mechanical compressive (P) and the shear (S) waves. The integration of both methods allowed to estimate the geomechanical parameters characterizing the studied sequence, the Poisson Ratio and the volumetric compressibility. The obtained mechanical parameters were correlated with laboratory measured parameters such as plasticity index, density, shear strength and compressibility and, GPR and seismic profiles were correlated with the mapped fracture systems in the study area. Once calibrated, the profiles allowed to identify the lithological contact between lacustrine and volcanic sequences, their variations of thicknesses in depth and to assess the deformation area in the surface. An accurate determination of the geometry of fracturing was of the most importance for the assessment of the geological risk in the study area.
DEFF Research Database (Denmark)
Lindgård, Per-Anker; Kowalska, A.; Laut, Peter
1967-01-01
A general bilinear two-Bose Hamiltonian is diagonalized and the result used in a discussion of non-imteracting spin waves in a two-sub-lattice ferromagnet having not negligible anisotropy in the spin interaction. Model-independent functions suitable for the analysis of experimental dispersion...... for the exchange interaction seem to be necessary for agreement with experimental dispersion curves be obtained. The effect of the anisotropy in the cross section is estimated and shown to be important for small magnon energies....
The Mean and Scatter of the Velocity Dispersion-Optical Richness Relation for MaxBCG Galaxy Clusters
Energy Technology Data Exchange (ETDEWEB)
Becker, M.R.; McKay, T.A.; /Michigan U.; Koester, B.; /Chicago U., Astron. Astrophys. Ctr.; Wechsler, R.H.; /KIPAC, Menlo Park /SLAC /Stanford U., Phys. Dept.; Rozo, E.; /Ohio State U.; Evrard, A.; /Michigan U. /Michigan U., MCTP; Johnston, D.; /Caltech, JPL; Sheldon, E.; /New York U.; Annis, J.; /Fermilab; Lau, E.; /Chicago U., Astron. Astrophys. Ctr.; Nichol, R.; /Portsmouth U., ICG; Miller, C.; /Michigan U.
2007-06-05
The distribution of galaxies in position and velocity around the centers of galaxy clusters encodes important information about cluster mass and structure. Using the maxBCG galaxy cluster catalog identified from imaging data obtained in the Sloan Digital Sky Survey, we study the BCG--galaxy velocity correlation function. By modeling its non-Gaussianity, we measure the mean and scatter in velocity dispersion at fixed richness. The mean velocity dispersion increases from 202 {+-} 10 km s{sup -1} for small groups to more than 854 {+-} 102 km s{sup -1} for large clusters. We show the scatter to be at most 40.5{+-}3.5%, declining to 14.9{+-}9.4% in the richest bins. We test our methods in the C4 cluster catalog, a spectroscopic cluster catalog produced from the Sloan Digital Sky Survey DR2 spectroscopic sample, and in mock galaxy catalogs constructed from N-body simulations. Our methods are robust, measuring the scatter to well within one-sigma of the true value, and the mean to within 10%, in the mock catalogs. By convolving the scatter in velocity dispersion at fixed richness with the observed richness space density function, we measure the velocity dispersion function of the maxBCG galaxy clusters. Although velocity dispersion and richness do not form a true mass--observable relation, the relationship between velocity dispersion and mass is theoretically well characterized and has low scatter. Thus our results provide a key link between theory and observations up to the velocity bias between dark matter and galaxies.
Institute of Scientific and Technical Information of China (English)
李伟; 魏彦玉; 谢鸿全; 刘盛纲; 巩马理
2003-01-01
A general dispersion equation of a partially filled plasma corrugated waveguide immersed in a finite magnetic field is presented. When the guiding magnet Bo →∞ or 0, this equation can be reduced to the results obtained in previous works.
DEFF Research Database (Denmark)
Ormarsson, Sigurdur; Dahlblom, Ola
2013-01-01
Wood is a hygro-mechanical, non-isotropic and inhomogeneous material concerning both modulus of elasticity (MOE) and shrinkage properties. In stress calculations associated with ordinary timber design, these matters are often not dealt with properly. The main reason for this is that stress...... distributions in inhomogeneous glued laminated members (glulam) and in composite beams exposed to combined mechanical action and variable climate conditions are extremely difficult to predict by hand. Several experimental studies of Norway spruce have shown that the longitudinal modulus of elasticity...... composites behave during both mechanical and environmental load action. The beam element is exposed to both axial and lateral deformation. The material model employed concerns the elastic, shrinkage, mechano-sorption and visco-elastic behaviour of the wood material. It is used here to simulate the behaviour...
Tethys- and Atlas-related deformations in the Triassic Basin, Algeria
Energy Technology Data Exchange (ETDEWEB)
Jackson, J.S.; Moore, S.R.; Quarles, A.I. [ARCO International Oil and Gas Company, Plano, TX (United States)
1995-08-01
Petroleum provinces of Algeria can be divided into Paleozoic and Mesozoic domains. Paleozoic basins are located on the Gondwanaland paleo-continent where the last significant tectonic episode is ascribed to the Late Paleozoic Hercynian Orogeny. Mesozoic basins are located on the south margin of the Neo-Tethyan seaway. These basins were subject to varying degrees of contractional deformation during the Cenozoic Atlas Orogeny. The Triassic Basin of Algeria is a Tethyan feature located above portions of the Paleozoic Oued M`ya and Ghadames Basins. Paleozoic strata are deeply truncated at the Hercynian Unconformity on a broad arch between the older basins. This is interpreted to reflect rift margin rebound during Carboniferous time. Continental Lower Triassic sediments were deposited in a series of northeast trending basins which opened as the Neo-Tethys basin propagated from east to west between Africa and Europe. Middle Triassic marine transgression from the east resulted in evaporate deposition persisting through the Early Jurassic. Passive margin subsidence associated with carbonate marine deposition continued through the Early Cretaceous. Several zones of coeval wrench deformation cross the Atlas and adjoining regions. In the Triassic Basin, inversion occurred before the end of the Early Cretaceous. This episode created discrete uplifts, where major hydrocarbon accumulations have been discovered, along northeast trending lineaments. During the Eocene, the main phase of the Atlas Orogeny produced low amplitude folding of Jurassic and Cretaceous sediments. The folds detach within the Triassic-Jurassic evaporate interval. Many of these folds have been tested without success, as the deeper reservoirs do not show structural closure.
Solutions of the benchmark problems by the dispersion-relation-preserving scheme
Tam, Christopher K. W.; Shen, H.; Kurbatskii, K. A.; Auriault, L.
1995-01-01
The 7-point stencil Dispersion-Relation-Preserving scheme of Tam and Webb is used to solve all the six categories of the CAA benchmark problems. The purpose is to show that the scheme is capable of solving linear, as well as nonlinear aeroacoustics problems accurately. Nonlinearities, inevitably, lead to the generation of spurious short wave length numerical waves. Often, these spurious waves would overwhelm the entire numerical solution. In this work, the spurious waves are removed by the addition of artificial selective damping terms to the discretized equations. Category 3 problems are for testing radiation and outflow boundary conditions. In solving these problems, the radiation and outflow boundary conditions of Tam and Webb are used. These conditions are derived from the asymptotic solutions of the linearized Euler equations. Category 4 problems involved solid walls. Here, the wall boundary conditions for high-order schemes of Tam and Dong are employed. These conditions require the use of one ghost value per boundary point per physical boundary condition. In the second problem of this category, the governing equations, when written in cylindrical coordinates, are singular along the axis of the radial coordinate. The proper boundary conditions at the axis are derived by applying the limiting process of r approaches 0 to the governing equations. The Category 5 problem deals with the numerical noise issue. In the present approach, the time-independent mean flow solution is computed first. Once the residual drops to the machine noise level, the incident sound wave is turned on gradually. The solution is marched in time until a time-periodic state is reached. No exact solution is known for the Category 6 problem. Because of this, the problem is formulated in two totally different ways, first as a scattering problem then as a direct simulation problem. There is good agreement between the two numerical solutions. This offers confidence in the computed results. Both
Bettison-Varga, Lori; Varga, Robert J.; Schiffman, Peter
1992-11-01
Field relations indicate that high-temperature hydrothermal circulation and accumulation of massive sulfide deposits within the Solea graben of the Troodos ophiolite, Cyprus, followed extreme crustal attenuation. Zones of pervasive, massive epidosite strike parallel to the axis of the Solea graben and to the strike of extensional normal faults. Initial fluid flow, evidenced by preferential epidotization in weakly altered areas surrounding massively altered regions, was focused along joints, microfractures, and (now) low-angle normal-fault zones related to graben formation. Permeability within the sheeted-dike section was enhanced by brittle deformation related to extensional structures as well as through volume reduction inherent in the diabase to epidosite mineralogic phase transformations. Intrusion of high-level gabbros into epidosite zones occurred both before and after significant amagmatic tectonic extension. Structural control on epidotization suggests that intrusion of late stocks into attenuated and highly deformed crust is necessary to drive the vigorous hydrothermal circulation that produced the epidosites and ore bodies of the Solea graben. A similar sequence of events is more likely to occur in the modern oceans along ridge crests with ephemeral magmatism, especially at intermediate- to slow-spreading ridges near transform faults.
Munari, Emiliano; Borgani, Stefano; Murante, Giuseppe; Fabjan, Dunja
2013-01-01
[Abridged] We present an analysis of the relation between the masses of cluster- and group-sized halos, extracted from $\\Lambda$CDM cosmological N-body and hydrodynamic simulations, and their velocity dispersions, at different redshifts from $z=2$ to $z=0$. The main aim of this analysis is to understand how the implementation of baryonic physics in simulations affects such relation, i.e. to what extent the use of the velocity dispersion as a proxy for cluster mass determination is hampered by the imperfect knowledge of the baryonic physics. In our analysis we use several sets of simulations with different physics implemented. Velocity dispersions are determined using three different tracers, DM particles, subhalos, and galaxies. We confirm that DM particles trace a relation that is fully consistent with the theoretical expectations based on the virial theorem and with previous results presented in the literature. On the other hand, subhalos and galaxies trace steeper relations, and with larger values of the n...
Buhmann, Stefan Yoshi
2012-01-01
In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...
Guo, Xiao; Wei, Peijun; Lan, Man; Li, Li
2016-08-01
The effects of functionally graded interlayers on dispersion relations of elastic waves in a one-dimensional piezoelectric/piezomagnetic phononic crystal are studied in this paper. First, the state transfer equation of the functionally graded interlayer is derived from the motion equation by the reduction of order (from second order to first order). The transfer matrix of the functionally graded interlayer is obtained by solving the state transfer equation with the spatial-varying coefficient. Based on the transfer matrixes of the piezoelectric slab, the piezomagnetic slab and the functionally graded interlayers, the total transfer matrix of a single cell is obtained. Further, the Bloch theorem is used to obtain the resultant dispersion equations of in-plane and anti-plane Bloch waves. The dispersion equations are solved numerically and the numerical results are shown graphically. Five kinds of profiles of functionally graded interlayers between a piezoelectric slab and a piezomagnetic slab are considered. It is shown that the functionally graded interlayers have evident influences on the dispersion curves and the band gaps.
Sorokin, Vladislav S; Thomsen, Jon Juel
2016-02-01
The paper deals with analytically predicting the effects of weak nonlinearity on the dispersion relation and frequency band-gaps of a periodic Bernoulli-Euler beam performing bending oscillations. Two cases are considered: (i) large transverse deflections, where nonlinear (true) curvature, nonlinear material and nonlinear inertia owing to longitudinal motions of the beam are taken into account, and (ii) mid-plane stretching nonlinearity. A novel approach is employed, the method of varying amplitudes. As a result, the isolated as well as combined effects of the considered sources of nonlinearities are revealed. It is shown that nonlinear inertia has the most substantial impact on the dispersion relation of a non-uniform beam by removing all frequency band-gaps. Explanations of the revealed effects are suggested, and validated by experiments and numerical simulation.
Szybisz, Leszek
1990-06-01
The self-consistency of solutions obtained from a recently proposed numerical relaxation method of solving the Euler-Lagrange equations for the ground state of inhomogeneous Bose systems at zero temperature is investigated. For this kind of system at least three different dispersion relations can be formulated, all of them providing information about the same eigenstates. The quality of our optimization scheme is studied by analyzing the convergence of the low-lying eigenvalues and eigenfunctions of these dispersion relations. Numerical results for the spectrum and spatial shape of elementary excitations of a thin film of liquid 4He supported by an external potential are reported. The optimal lowest-lying eigenvalues are compared with estimations based on simple theoretical approaches and with calculations performed by other authors.
Directory of Open Access Journals (Sweden)
Liu Yongjun
2015-01-01
Full Text Available In this thesis, the influence of complete Coriolis force (the model includes both the vertical and horizontal components of Coriolis force on the dispersion relation of ocean internal-wave under background currents field are studied, it is important to the study of ocean internal waves in density-stratified ocean. We start from the control equation of sea water movement in the background of the non-traditional approximation, and the vertical velocity solution is derived where buoyancy frequency N(z gradually varies with the ocean depth z. The results show that the influence of complete Coriolis force on the dispersion relation of ocean internal-wave under background currents field is obvious, and these results provide strong evidence for the understanding of dynamic process of density stratified ocean internal waves.
Institute of Scientific and Technical Information of China (English)
ZHONG Hong-Wei; TANG Yi
2006-01-01
@@ The phonon dispersion relation of the commensurate quantum Frenkel-Kontorova model is studied by means of the time-dependent variational approach combined with a Hartree-type many-body trial wavefunction for the particles. The single-particle state is taken to be a frozen Jackiw-Kerman wavefunction. Under the condition of minimum uncertainty, equations of motion for the particle expectation values are derived to obtain the phonon dispersion relation. It is shown that the strength of the substrate potential and the phonon excitation gap are reduced due to the quantum fluctuations in comparison with those of the classical model. We also compare our results with those previously obtained by using the path-integral molecular dynamics.
Institute of Scientific and Technical Information of China (English)
A.Hasanbeigi; H.Mehdian
2013-01-01
The effects of corrugated ion channels on electron trajectories and spatial growth rate for a free-electron laser with a one-dimensional helical wiggler have been investigated.Analysis of the steady-state electron trajectories is performed by solving the equations of motion.Our results show that the presence of a corrugated channel shifts the resonance frequency to smaller values of ion channel frequency.The sixth-order dispersion equation describing the coupling between the electrostatic beam mode and the electromagnetic mode has also been derived.The dispersion relation characteristic is analyzed in detail by numerical solution.Results show that the growth rate of instability in the presence of corrugated ion channels can be greatly enhanced relative to the case of an uniform ion channel.
Quantum dispersion relations for excitations of long folded spinning superstring in AdS_5 x S^5
Giombi, S; Roiban, R; Tseytlin, A A
2010-01-01
We use AdS_5 x S^5 superstring sigma model perturbation theory to compute the leading one-loop corrections to the dispersion relations of the excitations near a long spinning string in AdS. This investigation is partially motivated by the OPE-based approach to the computation of the expectation value of null polygonal Wilson loops suggested in arXiv:1006.2788. Our results are in partial agreement with the recent asymptotic Bethe ansatz computation in arXiv:1010.5237. In particular, we find that the heaviest AdS mode (absent in the ABA approach) is stable and has a corrected one-loop dispersion relation similar to the other massive modes. Its stability might hold also at the next-to-leading order as we suggest using a unitarity-based argument.
Once subtracted Roy-like dispersion relations and a precise analysis of $\\pi\\pi$ scattering data
Garcia-Martin, R; Peláez, J R; Ynduráin, F J
2009-01-01
We report our progress on the data analysis of $\\pi\\pi$ scattering data in terms of Forward Dispersion Relations (FDR), as well as Roy equations (RE) and their once-subtracted counterpart, GKPY equations. The first part of the analysis consists of independent fits to the different $\\pi\\pi$ channels. The GKPY equations provide a more stringent consistency check for the parametrizations of the S0-wave data in the region from 400 to 1100 MeV, In the second part we present our preliminary analysis where the fits are constrained to satisfy all dispersion relations within errors, including the new GKPY Eqs., thus providing a very precise and model independent description of data using just analyticity, causality and crossing.
DEFF Research Database (Denmark)
Bagger Jørgensen, Rikke; Hauser, Thure Pavlo; D'Hertefeldt, T.
2009-01-01
Background, aim, and scope We strive to predict consequences of genetically modified plants (GMPs) being cultivated openly in the environment, as human and animal health, biodiversity, agricultural practise and farmers’ economy could be affected. Therefore, it is unfortunate that the risk...... of fitness parameters. Monitoring of the extent of spontaneous introgression in natural populations was also performed. Modelling was used as an additional tool to identify key parameters in gene flow. Results The GM plant may affect the environment directly or indirectly by dispersal of the transgene....... In the present review, this is illustrated through a bunch of examples mostly from our own research on oilseed rape, Brassica napus. In the Brassica cases, the variability affected all five main steps in the process of gene dispersal. The modelling performed suggests that in Brassica, differences in fitness...
Dispersion of the Nabro volcanic plume and its relation to the Asian summer monsoon
Fairlie, T. D.; Vernier, J.-P.; M. Natarajan; Bedka, K M
2014-01-01
We use nighttime measurements from the Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, together with a Lagrangian trajectory model, to study the initial dispersion of volcanic aerosol from the eruption of Mt. Nabro (Ethiopia/Eritrea) in June 2011. The Nabro eruption reached the upper troposphere and lower stratosphere (UTLS) directly, and the plume was initially entrained by the flow surrounding the Asian anticyclone, which prevails in ...
Tso, Rhondale; Chen, Yanbei; Stein, Leo
2016-01-01
We propose a generic, phenomenological approach to modifying the dispersion of gravitational waves, independent of corrections to the generation mechanism. This model-independent approach encapsulates all previously proposed parametrizations, including Lorentz violation in the Standard-Model Extension, and provides a roadmap for additional theories. Furthermore, we present a general approach to include modulations to the gravitational-wave polarization content. The framework developed here can be implemented in existing data analysis pipelines for future gravitational-wave observation runs.
Ackerman, Joshua T.; Ringelman, Kevin M.; Eadie, J.M.
2012-01-01
When nest predation levels are very high or very low, the absolute range of observable nest success is constrained (a floor/ceiling effect), and it may be more difficult to detect density-dependent nest predation. Density-dependent nest predation may be more detectable in years with moderate predation rates, simply because there can be a greater absolute difference in nest success between sites. To test this, we replicated a predation experiment 10 years after the original study, using both natural and artificial nests, comparing a year when overall rates of nest predation were high (2000) to a year with moderate nest predation (2010). We found no evidence for density-dependent predation on artificial nests in either year, indicating that nest predation is not density-dependent at the spatial scale of our experimental replicates (1-ha patches). Using nearest-neighbor distances as a measure of nest dispersion, we also found little evidence for “dispersion-dependent” predation on artificial nests. However, when we tested for dispersion-dependent predation using natural nests, we found that nest survival increased with shorter nearest-neighbor distances, and that neighboring nests were more likely to share the same nest fate than non-adjacent nests. Thus, at small spatial scales, density-dependence appears to operate in the opposite direction as predicted: closer nearest neighbors are more likely to be successful. We suggest that local nest dispersion, rather than larger-scale measures of nest density per se, may play a more important role in density-dependent nest predation.
Peláez, J R; Kaminski, R; Ynduráin, F J
2009-01-01
This talk is dedicated to the memory of Paco Yndurain, the original speaker in the conference. After a short account of his scientific career, we briefly review our ongoing collaboration to determine precisely the $\\pi\\pi$ scattering amplitude including the most recent data by means of Forward Dispersion Relations and Roy Equations. A remarkable improvement in precision over the intermediate energy region is obtained by using once-subtracted Roy Equations in addition to the standard twice-subtracted ones.
Energy Technology Data Exchange (ETDEWEB)
Pelaez, J.R.; Garcia Martin, R. [Dept. de Fisica Teorica II, Univ. Complutense de Madrid. 28040 Madrid. Spain (Spain); Kaminski, R. [Department of Theoretical Physics Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-342, Krakow (Poland); Yndurain, F.J. [Dept. de Fisica Teorica, C-XI Univ. Autonoma de Madrid, Canto Blanco, E-28049, Madrid (Spain)
2009-01-15
This talk is dedicated to the memory of Paco Yndurain, the original speaker in the conference. After a short account of his scientific career, we briefly review our ongoing collaboration to determine precisely the {pi}{pi} scattering amplitude including the most recent data by means of Forward Dispersion Relations and Roy Equations. A remarkable improvement in precision over the intermediate energy region is obtained by using once-subtracted Roy Equations in addition to the standard twice-subtracted ones.
Migliano, P.; Zarzoso, D.; Artola, F. J.; Camenen, Y.; Garbet, X.
2017-09-01
The analytical treatment of plasma kinetic linear instabilities in toroidal geometry is commonly tackled employing a power series expansion of the resonant part of the dispersion relation. This expansion is valid under the assumption that the modulus of the mode frequency is smaller than the magnitude of the frequencies characterising the system (the drift, bounce and transit frequencies for example). We will refer to this approximation as high frequency approximation (HFA). In this paper the linear plasma dispersion relation is derived in the framework of the gyro-kinetic model, for the electrostatic case, in the local limit, in the absence of collisions, for a non rotating plasma, considering adiabatic electrons, in toroidal circular geometry, neglecting the parallel dynamics effect. A systematic analysis of the meaning and limitations of the HFA is performed. As already known, the HFA is not valid for tokamak relevant parameters. A new way to approximate the resonant part of the dispersion relation, called here Improved high frequency approximation (IHFA), is therefore proposed. A quantitative analysis of the ion temperature gradient (ITG) instability is presented. The IHFA is shown to be applicable to the treatment of the ITG instability in tokamaks.
Directory of Open Access Journals (Sweden)
Justyna Leszczewska
2012-01-01
Full Text Available Stress level due to existing body deformity as well as to the treatment with a corrective brace is one of factors influencing the quality of life of children with idiopathic scoliosis undergoing non-surgical management. The purpose of the study was to evaluate the stress level among children suffering from idiopathic scoliosis in relation to the method of treatment and the parameters of the deformity. Seventy-three patients with idiopathic scoliosis participated in the study. Fifty-two children were treated by means of physiotherapy, while 21 patients were treated with both Cheneau corrective brace and physiotherapy. To assess the stress level related to the deformity itself and to the method of treatment with corrective brace, the two Bad Sobernheim Stress Questionnaires (BSSQs were applied, the BSSQ Deformity and the BSSQ Brace, respectively.
Kojima, T
2007-01-01
We explicitly construct two classes of infinitly many commutative operators in terms of the deformed W-algebra $W_{qt}(sl_N^)$, and give proofs of the commutation relations of these operators. We call one of them local integrals of motion and the other nonlocal one, since they can be regarded as elliptic deformation of local and nonlocal integrals of motion for the $W_N$ algebra.
Weickenmeier, J; Jabareen, M
2014-11-01
The characteristic highly nonlinear, time-dependent, and often inelastic material response of soft biological tissues can be expressed in a set of elastic-viscoplastic constitutive equations. The specific elastic-viscoplastic model for soft tissues proposed by Rubin and Bodner (2002) is generalized with respect to the constitutive equations for the scalar quantity of the rate of inelasticity and the hardening parameter in order to represent a general framework for elastic-viscoplastic models. A strongly objective integration scheme and a new mixed finite element formulation were developed based on the introduction of the relative deformation gradient-the deformation mapping between the last converged and current configurations. The numerical implementation of both the generalized framework and the specific Rubin and Bodner model is presented. As an example of a challenging application of the new model equations, the mechanical response of facial skin tissue is characterized through an experimental campaign based on the suction method. The measurement data are used for the identification of a suitable set of model parameters that well represents the experimentally observed tissue behavior. Two different measurement protocols were defined to address specific tissue properties with respect to the instantaneous tissue response, inelasticity, and tissue recovery.
Lumbo-pelvic related indexes: impact on adult spinal deformity surgery.
Boissière, Louis; Vital, Jean-Marc; Aunoble, Stéphane; Fabre, Thierry; Gille, Olivier; Obeid, Ibrahim
2015-06-01
Lumbo-pelvic indexes appeared recently in the literature taking advantage from the relationship between pelvic incidence (PI) and lumbar lordosis (LL). Schwab proposed to subtract LL from PI (PI-LL) as Boissière proposed the lumbar lordosis index (LLI), which is the ratio between LL and PI (LL/PI). Both indexes have been described to weight LL by a constant parameter not affected by degenerative processes, the PI. The aim of this study is to evaluate these parameters in adult spinal deformity (ASD) by analyzing their relationship with spinal malalignment and vertebral osteotomies. Two groups of patients with an ASD were realized; an adult scoliosis group (n = 78) and a postoperative flat-back syndrome group (n = 20). In the adult scoliosis group, 28 patients underwent an osteotomy [pedicle subtraction osteotomy (PSO) or Smith Petersen osteotomy] and 50 patients were corrected by posterior fusion without osteotomy. In the postoperative flat-back syndrome group all patients underwent a PSO. All patients had preoperative and postoperative full spine EOS radiographies to measure spino-pelvic parameters. The lack of lordosis was calculated, after prediction of theoretical LL from Legaye's formula, by subtracting measured LL to theoretical LL. Correlation analysis between the different parameters was performed. Both lumbo-pelvic parameters highly correlated with spinal malalignment (r = 0.97 for PI-LL and r = -0.97 for LLI for total patients) and were highly predictive of a spinal osteotomy performance (r = 0.88 for PI-LL >28° and r = 0.94 for LLI Sagittal vertical axis (r = 0.67) and pelvic tilt (r = 0.64) correlated moderately with spinal malalignment for total patients. The LLI was more correlated with spinal osteotomies in the adult scoliosis group (r = 0.86 for PI-LL >28° and r = 0.94 for LLI flat-back syndrome group (Youden index = 0.95 for PI-LL >28° vs 0.90 for LLI sagittal correction. They can be used as well for the interpretation of clinical series in ASD.
Arrowsmith, R.; Crosby, C. J.
2010-12-01
Earthquake slip, fault zone geometric evolution, and geomorphic response to surface displacements from faulting are phenomena well manifest in topography at the meter scale. With laser ground return densities of multiple per square meter, LiDAR-derived topography provide a powerful tool to characterize features related to these processes at the appropriate scale. Many of the active faults in the western US, in particular the San Andreas Fault (SAF) system, have been scanned using LiDAR by community-oriented projects such as B4 and EarthScope. These data and many others (along with processed derivatives, dataset citation information, and educational and training materials) are available from the OpenTopography Facility (http://opentopography.org/). New meter-scale offsets along the SAF and other faults have been discovered and measured and known ones remeasured to provide a rich description of slip in the last few earthquakes. However, this method requires direct association of earthquake timing with measured (often cumulative) slip. Surface ruptures of recent earthquakes (Hector Mine, Denali, Sierra El Mayor) have been spectacularly documented by various research teams using LiDAR and other methods, and prepare us for future opportunities to directly measure post-event near field deformation with multi-temporal LiDAR surveys (the original motivator of the B4 project for the southern SAF and San Jacinto Fault). Cumulative ground deformation associated with repeated late Quaternary earthquakes produces the discontinuous fault zones well manifest in few km-wide swaths of LiDAR topography. Mapping these traces and associated landforms provides important ground rupture hazard information, locations of possible paleoseismic sites, and improved understanding of the structural geometry, mechanical behavior, and evolution of the shallow, velocity-strengthening portion of active fault zones. Fault-related deformation, in particular localized by geometric discontinuities
Nonlinear effects related to circularly polarized dispersive Alfvén waves
Sharma, Swati; Gaur, Nidhi; Sharma, R. P.
2016-09-01
In situ measurements of solar wind have strongly implicated its turbulent behavior. The observed power spectra report a breakpoint around length scales of the order of ion scales. As one of the responsible mechanisms for the observed steepening in power spectrum, our approach includes a right circularly polarized dispersive Alfvén wave (DAW) with finite frequency correction which, when subjected to transverse collapse/filamentation instability, may possibly result in steepening of spectrum and progressive transfer of energy from larger scales to smaller scales. We have studied the nonlinear effects associated with coupling of DAW with kinetic Alfvén wave in solar wind at 1 A.U. The formation of localized structures provides a clue about the emergence of turbulence. Numerical simulation is performed to study localization and power spectral density of the field and density fluctuations. The results show steeper spectrum indicating transfer of large scale turbulent energy down to small scales.
Ibáñez-Mejía, Juan C.; Mac Low, Mordecai-Mark; Klessen, Ralf S.; Baczynski, Christian
2016-06-01
Molecular cloud (MC) observations show that clouds have non-thermal velocity dispersions that scale with the cloud size as σ ∝ R 1/2 at a constant surface density, and for varying surface density scale with both the cloud’s size and surface density, σ 2 ∝ RΣ. The energy source driving these chaotic motions remains poorly understood. We describe the velocity dispersions observed in a cloud population formed in a numerical simulation of a magnetized, stratified, supernova (SN)-driven, interstellar medium, including diffuse heating and radiative cooling, before and after we include the effects of the self-gravity of the gas. We compare the relationships between velocity dispersion, size, and surface density measured in the simulated cloud population to those found in observations of Galactic MCs. Our simulations prior to the onset of self-gravity suggest that external SN explosions alone do not drive turbulent motions of the observed magnitudes within dense clouds. On the other hand, self-gravity induces non-thermal motions as gravitationally bound clouds begin to collapse in our model, approaching the observed relations between velocity dispersion, size, and surface density. Energy conservation suggests that the observed behavior is consistent with the kinetic energy being proportional to the gravitational energy. However, the clouds in our model show no sign of reaching a stable equilibrium state at any time, even for strongly magnetized clouds. We conclude that gravitationally bound MCs are always in a state of gravitational contraction and their properties are a natural result of this chaotic collapse. In order to agree with observed star formation efficiencies, this process must be terminated by the early destruction of the clouds, presumably from internal stellar feedback.
Templeman, B.; Raman, S.; Templeman, S.; Nigam, S.; Singh, M. P.
Digital analysis of smoke plume imagery is applied to video and photographs of a smoke plume taken on 22 June 1987 at the Badrapur Power Plant in New Delhi, India. Using a medium resolution video digitizer, these photographs and video are digitized and analyzed to produce a composite averaged plume that corresponds to a sampling interval of 2 min. These estimates are then used to estimate parameters of vertical dispersion and relative centerline concentration. Estimates of vertical dispersion are compared with Briggs' recommended values for stability class C (slightly unstable conditions). The digital technique produces values of σz that compare well with those estimated using Briggs' formulations. The values obtained using the digital method did not vary by more than 5 per cent from those formulated by Briggs. Estimates of relative concentration, which are values normalized by the concentration associated with a travel distance of 100 m, are compared with relative concentrations obtained using the Gaussian diffusion equation. The digital method produces estimates of relative concentration that compare well with the Gaussian diffusion equation, the differences encountered varying by less than 10 per cent throughout the calculated travel distance.
Bandy, W. L.; Castillo Maldonado, M.; Mortera-Gutierrez, C. A.
2014-12-01
The west coast of Mexico presents a complex pattern of deformation related to the convergence and subduction of the Rivera plate beneath the Jalisco Block/North American plate. Previous single beam bathymetric data have evidenced a large bathymetric high at 104.6218oW, 18.7123oN, in the continental slope region off Manzanillo, Mexico. One school of thought held that this high was the offshore extension of the onshore Manzanillo horst, although the two features are offset in a right-lateral sense. Alternatively, given the presence of a large positive magnetic anomaly near the bathymetric high, the high could also be caused by the collision and subsequent subduction of a large seamount. Given that the offset between the two structures was the main evidence for proposing the existence of a forearc sliver in the offshore area of the Jalisco margin, resolving the nature of this bathymetric high is quite important in our attempts to understand the plate kinematics and tectonics of this region. Thus, to better define the deformation pattern associated with the bathymetric high, multibeam bathymetric data (obtained using the Kongsberg EM300 multibeam system), subbottom profiles (obtained using the Kongsberg TOPAS18 system), and total field magnetic data (obtained using the Geometrics G877 marine proton precession magnetometer) were collected in the continental slope region between Manzanillo, Colima, and Chamela, Jalisco, during several cruises of UNAM´s research vessel the B.O. EL PUMA. The morphology and structural deformation patterns obtained in this study indicate very clearly that a large seamount is in the process of subducting beneath the continental slope off Manzanillo. The results also indicate that not only has the seamount uplifted the slope but has resulted in slumping of the area of the slope landward of the seamount. Given these results the proposal of the existence of an independent forearc sliver in the offshore area of the southern Jalisco block needs
Remiddi, Ettore
2016-01-01
It is shown that the study of the imaginary part and of the corresponding dispersion relations of Feynman graph amplitudes within the differential equations method can provide a powerful tool for the solution of the equations, especially in the massive case. The main features of the approach are illustrated by discussing the simple cases of the 1-loop self-mass and of a particular vertex amplitude, and then used for the evaluation of the two-loop massive sunrise and the QED kite graph (the problem studied by Sabry in 1962), up to first order in the (d-4) expansion.
Remiddi, Ettore; Tancredi, Lorenzo
2016-06-01
It is shown that the study of the imaginary part and of the corresponding dispersion relations of Feynman graph amplitudes within the differential equations method can provide a powerful tool for the solution of the equations, especially in the massive case. The main features of the approach are illustrated by discussing the simple cases of the 1-loop self-mass and of a particular vertex amplitude, and then used for the evaluation of the two-loop massive sunrise and the QED kite graph (the problem studied by Sabry in 1962), up to first order in the (d - 4) expansion.
DEFF Research Database (Denmark)
Gryning, Sven-Erik; Larsen, Søren Ejling
1981-01-01
A simple model was described that related the dispersion of material from ground-level sources at 2 areas, taking into account dissimilarities in the surface roughness parameter (z0) and the atmospheric stability characterized by the Monin-Obukhov length (L). The geostrophic wind speed was assumed...... that travelled a distance x; .hivin.z/L was found when z0/L and x/z0 were known. The model was reduced to 3 dimensionless parameters by merging .hivin.z/L for the 2 areas into a composite parameter. Dimensionless results from the model were illustrated for discrete values of this composite parameter....
Institute of Scientific and Technical Information of China (English)
ChengWanzheng; YangYongling
2003-01-01
Deformation measurements such as short-range leveling, short-baseline, continuous cross-fault strain measurement are carried out at different intervals from 1982 to 2001. All these measurement sites are built across the boundary tectonic belts of Yunnan-Sichuan block. On the basis of these deformation data, the annual deformation rates at all sites are calculated and their change curves with time are plotted respectively. With these calculated results, we analyze the vertical and horizontal movements of tectonic belts of Yunnan-Sichuan block, and the relationship to grouped strong earthquakes occurred in the block are discussed as well. These results show that the tectonic activities in the western and southeastern Yunnan are intensive. Along some eastern boundary belts: from Qujiang, Xiaojiang fault belts in the south of Yunnan to Xianshuihe fault belts in northwestern Sichuan, present annual rate of horizontal deformation decreases. Along Xianshuihe, Xiaojiang and Longmenshan fault belts the rates of vertical deformation change are small, but the vertical deformation change rates along Anninghe and Zemuhe faul tbelts are comparatively large. The comprehensive analysis shows that grouped strong earthquakes will occur probably when the deformation rate changes sharply. Thus we think that sharp changes of deformation rates may be one of the seismic precursors.
Institute of Scientific and Technical Information of China (English)
Cheng Wanzheng; Yang Yongling
2003-01-01
Deformation measurements such as short-range leveling, short-baseline, continuous cross-fault strain measurement are carried out at different intervals from 1982 to 2001. All these measurement sites are built across the boundary tectonic belts of Yunnan-Sichuan block. On the basis of these deformation data, the annual deformation rates at all sites are calculated and their change curves with time are plotted respectively. With these calculated results, we analyze the vertical and horizontal movements of tectonic belts of Yunnan-Sichuan block, and the relationship to grouped strong earthquakes occurred in the block are discussed as well. These results show that the tectonic activities in the western and southeastern Yunnan are intensive. Along some eastern boundary belts: from Qujiang, Xiaojiang fault belts in the south of Yunnan to Xianshuihe fault belts in northwestern Sichuan, present annual rate of horizontal deformation decreases. Along Xianshuihe, Xiaojiang and Longmenshan fault belts the rates of vertical deformation change are small, but the vertical deformation change rates along Anninghe and Zemuhe fault belts are comparatively large. The comprehensive analysis shows that grouped strong earthquakes will occur probably when the deformation rate changes sharply. Thus we think that sharp changes of deformation rates may be one of the seismic precursors.
Bustin, Amanda M. M.
dislocation modelling showed that the majority of the transpressive Pacific/North America motion is accommodated along the locked Queen Charlotte Fault zone and thrust fault with the remaining plate motion taken up by north-northeast migration of the margin at rates of ˜6 mm/yr. The migration is also supported by the stress pattern derived from focal mechanisms. However, the GPS determined deformation rates are much greater than the rates estimated in the Queen Charlotte Basin from the seismicity catalogue. The extra shortening could be accommodated by large characteristic thrust earthquakes within the basin. The deformation rates estimated from the seismicity along the Queen Charlotte Fault zone are consistent with the relative Pacific/North America plate motion; however, the seismic moment released by thrust earthquakes along the fault is insufficient to account for the component of convergence. This suggests that large thrust earthquakes may occur along the plate boundary. An additional part of this dissertation involved constraining the rupture parameters of the Nisqually earthquake, a M 6.8 event which occurred on February 28, 2001 within the subducting Juan de Fuca slab at the Cascadia subduction zone. The fault parameters of the event were estimated from moment tensor solutions, and by comparing the surface displacements from GPS and InSAR data, with predictions from elastic deformation models. The results are in agreement with the earthquake mechanism from waveform analyses, but provide substantially stronger constraints.
Influence of the relative deformation rate on tube processing by ultrasonic vibration drawing
Directory of Open Access Journals (Sweden)
Susan, M.
2004-04-01
Full Text Available After a brief review of the "friction reversion mechanism" during ultrasonic vibration drawing of tubes (UVD, the paper introduces a method to determine the drawing force based on the theorem of total consumed power, in the case of tube processing. The experiments performed on tubes made from 10TiNiCr180 (AISI321 austenitic stainless steel confirm the superiority of UVD technology regarding the diminution of the drawing force, the increase of the plasticity and the improvement of the safety coefficient, tendencies that are enhanced with the decrease of the relative drawing rate. The best results were obtained for the relative drawing rate of 0.12 for which the drawing force decreased with 33 %, plasticity increased with 9 % and safety coefficient with 22 %, as compared to CT.
Después de un breve resumen del mecanismo de reversión de la fricción al estirado por vibraciones ultrasonoras (EVU, el trabajo propone un método para calcular la fuerza de estirado en base al teorema de la potencia total consumida, en el caso particular de la elaboración de tubos. Los experimentos realizados con tubos de acero inoxidable austenítico 10TiNiCr180 (AISI321 demuestran la superioridad de la tecnología EVU sobre la tecnología clásica (TC, en lo concerniente a la reducción de la fuerza de estirado, el incremento de la plasticidad y la mejora del coeficiente de seguridad, tendencias que se acentúan al diminuirse la velocidad relativa de estirado. Los mejores resultados se han obtenido en el caso de la velocidad relativa de 0,12, para la cual la fuerza de estirado se redujo, aproximadamente, un 33 %; la plasticidad se incrementó en el 9 %; y el coeficiente de seguridad aumentó un 22 % frente a la TC.
Indian Academy of Sciences (India)
Ramaswamy Jaganathan; Sudeshna Sinha
2005-03-01
Motivated by studies on -deformed physical systems related to quantum group structures, and by the elements of Tsallis statistical mechanics, the concept of -deformed nonlinear maps is introduced. As a specific example, a -deformation procedure is applied to the logistic map. Compared to the canonical logistic map, the resulting family of -logistic maps is shown to have a wider spectrum of interesting behaviours, including the co-existence of attractors – a phenomenon rare in one-dimensional maps.
Kanoun, Mohammed
2014-06-26
We compared the mechanism of O2 dissociation catalyzed by Cu38, Ag38, and Au38 nanoparticles. Overall, our results indicate that O2 dissociation is extremely easy on Cu38, with an almost negligible barrier for the O-O breaking step. It presents an energy barrier close to 20 kcal/mol on Ag38, which decreases to slightly more than 10 kcal/mol on Au38. This behavior is analyzed to quantify the impact of relativity and of dispersion interactions through a comparison of nonrelativistic, scalar-relativistic, and dispersioncorrected DFT methods. Nonrelativistic calculations show a clear trend down the triad, with larger in size nanoparticle (NP), weaker O2 adsorption energy, and higher O2 dissociation barrier, which is so high for Au38 to be in sharp contrast with the mild conditions used experimentally. Inclusion of relativity has no impact on the O2 adsorption energy, but it reduces the energy barrier for O2 dissociation on Au38 from 30.1 to 11.4 kcal/mol, making it even lower than that on Ag38 and consistent with the mild conditions used experimentally. Dispersion interactions have a remarkable role in improving the adsorption ability of O2 on the heavier Ag38 and especially Au38 NPs, contributing roughly 50% of the total adsorption energy, while they have much less impact on O2 adsorption on Cu38.
Wilson, Susan; Hilton, Matt; Rooney, Philip J.; Caldwell, Caroline; Kay, Scott T.; Collins, Chris A.; McCarthy, Ian G.; Romer, A. Kathy; Bermeo, Alberto; Bernstein, Rebecca; da Costa, Luiz; Gifford, Daniel; Hollowood, Devon; Hoyle, Ben; Jeltema, Tesla; Liddle, Andrew R.; Maia, Marcio A. G.; Mann, Robert G.; Mayers, Julian A.; Mehrtens, Nicola; Miller, Christopher J.; Nichol, Robert C.; Ogando, Ricardo; Sahlén, Martin; Stahl, Benjamin; Stott, John P.; Thomas, Peter A.; Viana, Pedro T. P.; Wilcox, Harry
2016-11-01
We measure the evolution of the velocity dispersion-temperature (σv-TX) relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the Gemini Multi Object Spectographs instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalization is slightly negative, but not significantly different from zero (σv ∝ T0.86±0.14E(z)-0.37±0.33). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.
Giant Magnon on Deformed AdS(3)xS(3)
Khouchen, Malak
2014-01-01
We study giant magnon solutions for strings moving on a deformed AdS(3)xS(3) background. We impose a conformal gauge on the Polyakov action and proceed with solving the Virasoro constraints. The expressions of the conserved charge J and the energy of a single magnon excitation are then computed. Then we determine the dispersion relation in the infinite J limit configuration and we find that it reduces to celebrated Hofman-Maldacena dispersion relation when the deformation parameter goes to zero.
Mechanical properties and constitutive relations for molybdenum under high-rate deformation
Energy Technology Data Exchange (ETDEWEB)
Chen, S.R.; Maudlin, P.J.; Gray, G.T. III
1998-01-01
Molybdenum and its alloys have received increased interest in recent years for ballistic applications. The stress-strain behavior of several molybdenums possessing various compositions, manufacturing sources, and the degree of pre-straining, were investigated as a function of temperature from 77 to 1,273 K, and strain rate from 10{sup {minus}3} s{sup {minus}1} to 8,000 s{sup {minus}1}. The yield stress was found to be sensitive to the test temperature and strain rate, however, the strain hardening remained rate-insensitive. The constitutive response of a powder-metallurgy molybdenum was also investigated; similar mechanical properties compared to conventionally wrought processed molybdenums were achieved. Constitutive relations based upon the Johnson-Cook, the Zerilli-Armstrong and the Mechanical Threshold Stress (MTS) models were evaluated and fit for the various Mo-based materials. The capabilities and limitations of each model for large-strain applications were examined. The differences between the three models are demonstrated using model comparisons to Taylor cylinder validation experiments.
Directory of Open Access Journals (Sweden)
Valentina Boccia
2015-01-01
Full Text Available Long gravity waves or swell dominating the sea surface is known to be very useful to estimate seabed morphology in coastal areas. The paper reviews the main phenomena related to swell waves propagation that allow seabed morphology to be sensed. The linear dispersion is analysed and an error budget model is developed to assess the achievable depth accuracy when Synthetic Aperture Radar (SAR data are used. The relevant issues and potentials of swell-based bathymetry by SAR are identified and discussed. This technique is of particular interest for characteristic regions of the Mediterranean Sea, such as in gulfs and relatively close areas, where traditional SAR-based bathymetric techniques, relying on strong tidal currents, are of limited practical utility.
Boccia, Valentina; Renga, Alfredo; Rufino, Giancarlo; D'Errico, Marco; Moccia, Antonio; Aragno, Cesare; Zoffoli, Simona
2015-01-01
Long gravity waves or swell dominating the sea surface is known to be very useful to estimate seabed morphology in coastal areas. The paper reviews the main phenomena related to swell waves propagation that allow seabed morphology to be sensed. The linear dispersion is analysed and an error budget model is developed to assess the achievable depth accuracy when Synthetic Aperture Radar (SAR) data are used. The relevant issues and potentials of swell-based bathymetry by SAR are identified and discussed. This technique is of particular interest for characteristic regions of the Mediterranean Sea, such as in gulfs and relatively close areas, where traditional SAR-based bathymetric techniques, relying on strong tidal currents, are of limited practical utility.
Energy Technology Data Exchange (ETDEWEB)
Rutqvist, J.
2010-06-01
This paper presents recent advancement in and applications of TOUGH-FLAC, a simulator for multiphase fluid flow and geomechanics. The TOUGH-FLAC simulator links the TOUGH family multiphase fluid and heat transport codes with the commercial FLAC{sup 3D} geomechanical simulator. The most significant new TOUGH-FLAC development in the past few years is a revised architecture, enabling a more rigorous and tight coupling procedure with improved computational efficiency. The applications presented in this paper are related to modeling of crustal deformations caused by deep underground fluid movements and pressure changes as a result of both industrial activities (the In Salah CO{sub 2} Storage Project and the Geysers Geothermal Field) and natural events (the 1960s Matsushiro Earthquake Swarm). Finally, the paper provides some perspectives on the future of TOUGH-FLAC in light of its applicability to practical problems and the need for high-performance computing capabilities for field-scale problems, such as industrial-scale CO{sub 2} storage and enhanced geothermal systems. It is concluded that despite some limitations to fully adapting a commercial code such as FLAC{sup 3D} for some specialized research and computational needs, TOUGH-FLAC is likely to remain a pragmatic simulation approach, with an increasing number of users in both academia and industry.
Rutqvist, Jonny
2011-06-01
This paper presents recent advancement in and applications of TOUGH-FLAC, a simulator for multiphase fluid flow and geomechanics. The TOUGH-FLAC simulator links the TOUGH family multiphase fluid and heat transport codes with the commercial FLAC 3D geomechanical simulator. The most significant new TOUGH-FLAC development in the past few years is a revised architecture, enabling a more rigorous and tight coupling procedure with improved computational efficiency. The applications presented in this paper are related to modeling of crustal deformations caused by deep underground fluid movements and pressure changes as a result of both industrial activities (the In Salah CO 2 Storage Project and the Geysers Geothermal Field) and natural events (the 1960s Matsushiro Earthquake Swarm). Finally, the paper provides some perspectives on the future of TOUGH-FLAC in light of its applicability to practical problems and the need for high-performance computing capabilities for field-scale problems, such as industrial-scale CO 2 storage and enhanced geothermal systems. It is concluded that despite some limitations to fully adapting a commercial code such as FLAC 3D for some specialized research and computational needs, TOUGH-FLAC is likely to remain a pragmatic simulation approach, with an increasing number of users in both academia and industry.
DEFF Research Database (Denmark)
Møller, Jacob E; Husic, Mirza; Søndergaard, Eva
2002-01-01
OBJECTIVE: To describe the relation between changes of left ventricular systolic and diastolic function and changes of QT dispersion (difference in duration between longest and shortest QT interval) following acute myocardial infarction. DESIGN: QT dispersion was determined at admission, hospital...... normalized QT dispersion was associated with a significant decrease of ventricular volumes. After 1 year end-systolic (70 +/- 32 ml vs 49 +/- 16 ml, p = 0.006) and end-diastolic volumes (138 +/- 41 ml vs 105 +/- 22 ml, p = 0.001) were higher in Group B. In a multivariate model Group B was significantly...
Indian Academy of Sciences (India)
Abhik Kundu; Bapi Goswami; Patrick G Eriksson; Abhijit Chakraborty
2011-02-01
The Raniganj basin in the Damodar valley of eastern India is located within the riftogenic Gondwana Master-Basin. The fluvio-lacustrine deposits of the Lower Triassic Panchet Formation of the Damodar valley in the study area preserve various soft-sediment deformation structures such as slump folds, convolute laminae, flame structures, dish-and-pillar structures, sandstone dykes, pseudonodules and syn-sedimentary faults. Although such soft-sediment deformation structures maybe formed by various processes, in the present area the association of these structures, their relation to the adjacent sedimentary rocks and the tectonic and depositional setting of the formation suggest that these structures are seismogenic. Movements along the basin margin and the intra-basinal faults and resultant seismicity with moderate magnitude (2–5 on Richter scale) are thought to have been responsible for the soft-sediment deformations.
Jung, W-S; Kim, H; Jeon, D-M; Mah, S-J; Ahn, S-J
2013-09-01
This retrospective study was designed to analyze the relationships between temporomandibular joint (TMJ) disk displacement and skeletal deformities in orthodontic patients. Subjects consisted of 460 adult patients. Before treatment, lateral cephalograms and TMJ magnetic resonance imaging (MRI) were recorded. Subjects were divided into six groups based on TMJ MRI according to increasing severity of TMJ disk displacement, in the following order: bilateral normal TMJs, unilateral disk displacement with reduction (DDR) and contralateral normal, bilateral DDR, unilateral disk displacement without reduction (DDNR) and contralateral normal, unilateral DDR and contralateral DDNR, and bilateral DDNR. Subjects were subdivided sagittally into skeletal Class I, II, and III deformities based on the ANB (point A, nasion, point B) angle and subdivided vertically into hypodivergent, normodivergent, and hyperdivergent deformities based on the facial height ratio. Linear trends between severity of TMJ disk displacement and sagittal or vertical deformities were analyzed by Cochran-Mantel-Haenszel test. The severity of TMJ disk displacement increased as the sagittal skeletal classification changed from skeletal Class III to skeletal Class II and the vertical skeletal classification changed from hypodivergent to hyperdivergent. There were no significant differences in the linear trend of TMJ disk displacement severity between the sexes according to the skeletal deformities. This study suggests that subjects with skeletal Class II and/or hyperdivergent deformities have a high possibility of severe TMJ disk displacement, regardless of sex. Copyright © 2013 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Stellar Populations across the Black Hole Mass-Velocity Dispersion Relation
Martín-Navarro, Ignacio; Brodie, Jean P.; van den Bosch, Remco C. E.; Romanowsky, Aaron J.; Forbes, Duncan A.
2016-11-01
Coevolution between supermassive black holes (BH) and their host galaxies is universally adopted in models for galaxy formation. In the absence of feedback from active galactic nuclei (AGNs), simulated massive galaxies keep forming stars in the local universe. From an observational point of view, however, such coevolution remains unclear. We present a stellar population analysis of galaxies with direct BH mass measurements and the BH mass-σ relation as a working framework. We find that over-massive BH galaxies, i.e., galaxies lying above the best-fitting BH mass-σ line, tend to be older and more α-element-enhanced than under-massive BH galaxies. The scatter in the BH mass-σ-[α/Fe] plane is significantly lower than that in the standard BH mass-σ relation. We interpret this trend as an imprint of AGN feedback on the star formation histories of massive galaxies.
Zhang, Shu-Lin; Xia, Lei; Chen, Weihua; Li, D. Y.; Li, Wanyu; He, Juan
2016-12-01
The phonon dispersion relation (PDR), i.e., the dependence of phonon frequency ω on its wavevector q, ω(q), was measured traditionally by inelastic neutron scattering (INS) or inelastic X-ray scattering (IXS). A new approach to measure PDR by Raman scattering (RS) of nanostructures was proposed and applied to observe the longitudinal optical (LO) PDR of diamond successfully. Due to the higher resolution and accuracy of ω and q in RS, a clear downbending feature of ω with increasing q away from the Brillouin zoon center was observed for the first time. The validity of the new approach has been confirmed also by the appearing of the downward bending in PDR, which is originally measured by traditional high-resolution IXS experiment. The downbending feature may give us a clue for deep understanding of the interactions occur in diamond, while the overbending feature observed by INS and IXS has been attributed to strong effective second-nearest-neighbor forces.
Herbert, Eric; Mordant, Nicolas; Falcon, Eric
2010-10-01
We report experiments on gravity-capillary wave turbulence on the surface of a fluid. The wave amplitudes are measured simultaneously in time and space by using an optical method. The full space-time power spectrum shows that the wave energy is localized on several branches in the wave-vector-frequency space. The number of branches depends on the power injected within the waves. The measurement of the nonlinear dispersion relation is found to be well described by a law suggesting that the energy transfer mechanisms involved in wave turbulence are restricted not only to purely resonant interaction between nonlinear waves. The power-law scaling of the spatial spectrum and the probability distribution of the wave amplitudes at a given wave number are also measured and compared to the theoretical predictions.
DEFF Research Database (Denmark)
Bagger Jørgensen, Rikke; Hauser, Thure Pavlo; D'Hertefeldt, T.
2009-01-01
Background, aim, and scope We strive to predict consequences of genetically modified plants (GMPs) being cultivated openly in the environment, as human and animal health, biodiversity, agricultural practise and farmers’ economy could be affected. Therefore, it is unfortunate that the risk...... is a valuable tool in identifying key factors in the gene-flow process for which more knowledge is needed, and identifying parameters and processes which are relatively insensitive to change and therefore require less attention in future collections of data. But the interdependence between models...
Arabsalmani, Maryam; Fynbo, Johan P U; Christensen, Lise; Freudling, Wolfram; Savaglio, Sandra; Zafar, Tayyaba
2014-01-01
We analyze a sample of 16 absorption systems intrinsic to long duration GRB host galaxies at $z \\gtrsim 2$ for which the metallicities are known. We compare the relation between the metallicity and cold gas velocity width for this sample to that of the QSO-DLAs, and find complete agreement. We then compare the redshift evolution of the mass-metallicity relation of our sample to that of QSO-DLAs and find that also GRB hosts favour a late onset of this evolution, around a redshift of $\\approx 2.6$. We compute predicted stellar masses for the GRB host galaxies using the prescription determined from QSO-DLA samples and compare the measured stellar masses for the four hosts where stellar masses have been determined from SED fits. We find excellent agreement and conclude that, on basis of all available data and tests, long duration GRB-DLA hosts and intervening QSO-DLAs are consistent with being drawn from the same underlying population. GRB host galaxies and QSO-DLAs are found to have different impact parameter di...
Diurnal variation and dispersion in QT interval in cirrhosis: relation to haemodynamic changes
DEFF Research Database (Denmark)
Hansen, Stig; Møller, Søren; Bendtsen, Flemming
2007-01-01
with cirrhosis, undergoing a haemodynamic investigation. 24-h 12 lead Holter monitoring provided information on QT and heart rate variability. RESULTS: Mean QT(C) was above upper normal limit (440 ms(1/2)) in eleven patients (47%) and significantly higher than in controls (441 vs 400 ms(1/2), p...=0.03-0.001). No diurnal variation of QT(disp) was found in cirrhosis. Heart rate variability was reduced with a significant relation to central hypovolaemia (r=0.55, p=0.01). CONCLUSIONS: Twenty-four hours QT(C) is prolonged in a substantial fraction of patients with cirrhosis, but with normal...... diurnal variation. The combination of long QT(C) and normal QT(disp) suggests delayed myocyte repolarisation on the cellular level, rather than temporal and spatial heterogeneity in the myocardial wall....
DIFFUSIVE-DISPERSIVE TRAVELING WAVES AND KINETIC RELATIONS IV.COMPRESSIBLE EULER EQUATIONS
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
The authors consider the Euler equations for a compressible fluid in one space dimensionwhen the equation of state of the fluid does not fulfill standard convexity assumptions andviscosity and capillarity effects are taken into account. A typical example of nonconvex con-stitutive equation for fluids is Van der Waals' equation. The first order terms of these partialdifferential equations form a nonlinear system of mixed (hyperbolic-elliptic) type. For a class ofnonconvex equations of state, an existence theorem of traveling waves solutions with arbitrarylarge amplitude is established here. The authors distinguish between classical (compressive) andnonclassical (undercompressive) traveling waves. The latter do not fulfill Lax shock inequali-ties, and are characterized by the so-called kinetic relation, whose properties are investigatedin this paper.
Cruz, Raquel; Vilas, Carlos; Mosquera, Javier; García, Carlos
2004-12-01
Habitat preference behavior may play an important role in nonallopatric speciation. However, most examples of habitat preference contributing to differentiation within natural populations correspond to parasites or herbivores living in the discrete environments constituted by their animal or plant hosts. In the present study we investigated migration guided by habitat preference in the intertidal snail Littorina saxatilis in a hybrid zone associated with an ecotone across the shore, which is therefore a continuously varying environment. First, we found evidence for this behavior in one of the two locations studied. Second, we made reciprocal transplants to suppress the phenotypic gradient observed across the hybrid zone and measured the relative contributions of selection and migration to its regeneration. Selection played an important role at the two locations studied, but migration was only important at one, where it accounted for between a third and a half of the regenerated gradient. This overall minor effect of migration was relevant for theoretical models dealing with nonallopatric speciation, because it suggested that variation for habitat preference did not have an important role in the initiation of the differentiation process. The preference behavior observed in the hybrid zone would have evolved secondarily, as a consequence of habitat-dependent fitness differences between phenotypes.
Directory of Open Access Journals (Sweden)
Günther Zeck
Full Text Available BACKGROUND: Visual stimuli elicit action potentials in tens of different retinal ganglion cells. Each ganglion cell type responds with a different latency to a given stimulus, thus transforming the high-dimensional input into a temporal neural code. The timing of the first spikes between different retinal projection neurons cells may further change along axonal transmission. The purpose of this study is to investigate if intraretinal conduction velocity leads to a synchronization or dispersion of the population signal leaving the eye. METHODOLOGY/PRINCIPAL FINDINGS: We 'imaged' the initiation and transmission of light-evoked action potentials along individual axons in the rabbit retina at micron-scale resolution using a high-density multi-transistor array. We measured unimodal conduction velocity distributions (1.3±0.3 m/sec, mean ± SD for axonal populations at all retinal eccentricities with the exception of the central part that contains myelinated axons. The velocity variance within each piece of retina is caused by ganglion cell types that show narrower and slightly different average velocity tuning. Ganglion cells of the same type respond with similar latency to spatially homogenous stimuli and conduct with similar velocity. For ganglion cells of different type intraretinal conduction velocity and response latency to flashed stimuli are negatively correlated, indicating that differences in first spike timing increase (up to 10 msec. Similarly, the analysis of pair-wise correlated activity in response to white-noise stimuli reveals that conduction velocity and response latency are negatively correlated. CONCLUSION/SIGNIFICANCE: Intraretinal conduction does not change the relative spike timing between ganglion cells of the same type but increases spike timing differences among ganglion cells of different type. The fastest retinal ganglion cells therefore act as indicators of new stimuli for postsynaptic neurons. The intraretinal dispersion
Deformation of Linked Polymer Coils
Institute of Scientific and Technical Information of China (English)
董朝霞; 李明远; 吴肇亮; 林梅钦
2003-01-01
Linked polymer solution (LPS) is defined as the solution of linked polymer coils (LPCs) dispersed in water, composed of low concentration partially hydrolyzed polyacrylamide (HPAM) and aluminum citrate (crosslinker). In the work, the conformational changes of LPCs under different conditions were investigated by the methods of membrane filtering under low pressure, dynamic light scattering and core flooding experiments. The results showed that in some conditions the LPCs could be compressed mechanically to 1/158.5 of their original volume because of relatively lower HPAM cross-linking. The hydration property of LPCs was similar to that of normal polymer coils. The deformation of LPCs was more restricted than that of ordinary polymer coils under the flow shear stress or the shift of hydration equilibrium caused in the variation of the electrolyte concentration which is responsible for the effective plugging in the throats of porous media when LPCs are used for deep diverting.
Solomon, Rance; Cooper, James; Welker, Gabriel; Aguilar, Elaura; Flanagan, Brooke; Pennycuff, Chelsey; Scott, David; Farone, Anthony; Farone, Mary; Erenso, Daniel; Mushi, Robert; del Pilar Aguinaga, Maria
2013-06-01
Genetic mutation of the β-globin gene or inheritance of this mutated gene changes the chemical composition of the oxygen-carrying hemoglobin molecule that could lead to either the heterozygote genotype, resulting in sickle cell trait (SCT), or the homozygote genotype, resulting in sickle cell anemia (SCA). These mutations could affect the reversible elastic deformations of the red blood cells (RBCs) which are vital for biological functions. We have investigated this effect by studying the differences in the deformability of RBCs from blood samples of an individual with SCT and an untreated patient with SCA along with hemoglobin quantitation of each blood sample. Infrared 1064 nm laser trap force along with drag shear force are used to induce deformation in the RBCs. Ultra2-High Performance Liquid Chromatography (UHPLC) is used for the hemoglobin quantitation.
Zel'dovich, V. I.; Frolova, N. Yu.; Kheifets, A. E.; Dolgikh, S. M.; Gaan, K. V.; Shorokhov, E. V.
2015-03-01
An experiment has been performed on the collapse of a thick steel cylindrical shell into a continuous cylinder under the action of a sliding detonation wave. The process of the collapse has been recorded via X-ray photography, and it has been found that the time of collapse in one section is equal to 30 μs. The average degree of deformation is 77% and the rate of deformation is 104 s-1. The structure of steel 20 in the transverse section of the cylinder consists of three zones. In the outer zone, the initial ferrite-pearlite structure changes under the effect of compressive shock wave and localized shears. The shock wave leads to the formation of a high-pressure ɛ phase and twins. Upon the subsequent inertial collapse of the shell, substantial shear deformations arise in the surface layer, which are localized in directions located at angles of 60° to the cylindrical surface. The structure of the middle zone changes under the action of severe plastic deformation, which occurs predominantly in the radial direction. The deformation leads to the appearance of an internal pressure and to an increase in the temperature. As a result of the action of three factors (pressure, temperature, and deformation), the temperature of the formation of austenite decreases by several hundred kelvins. In the free ferrite, an α → γ transformation occurs and quenching takes place following a subsequent sharp decrease in pressure (barothermic quenching). The pearlitic regions suffer plastic deformation. The microhardness of the steel with this structure is equal to the microhardness of quenched steel. The structure of the third, i.e., central, zone, changes under the action of a significant increase in temperature caused by the further increase in the degree of deformation. The complete transformation of ferrite into austenite occurs at the center of this zone, which means that the temperature in this zone reaches 850-900°C or greater. The microhardness decreases to values typical
Howle, J.F.; Langbein, J.O.; Farrar, C.D.; Wilkinson, S.K.
2003-01-01
Regional first-order leveling lines, which extend from Lee Vining, CA, to Tom's Place, CA, have been surveyed periodically since 1957 by the U.S. Geological Survey (USGS), the National Geodetic Survey (NGS), and Caltrans. Two of the regional survey lines, or leveling networks, intersect at the Casa Diablo geothermal well field. These leveling networks, referenced to a distant bench mark (C916) near Lee Vining, provide time-series vertical control data of land-surface deformation that began around 1980. These data are also useful for delineating localized subsidence at Casa Diablo related to reservoir pressure and temperature changes owing to geothermal development that began in 1985. A comparison of differences in bench-mark elevations for five time periods between 1983 and 1997 shows the development and expansion of a subsidence bowl at Casa Diablo. The subsidence coincides spatially with the geothermal well field and temporally with the increased production rates and the deepening of injection wells in 1991, which resulted in an increase in the rate of pressure decline. The subsidence, superimposed on a broad area of uplift, totaled about 310 mm by 1997. The USGS established orthogonal tilt arrays in 1983 to better monitor deformation across the caldera. One tilt array (DBR) was established near what would later become the Casa Diablo geothermal well field. This array responded to magmatic intrusions prior to geothermal development, tilting away from the well field. With the start of geothermal fluid extraction in 1985, tilt at the DBR array reversed direction and began tilting into the well field. In 1991, geothermal power production was increased by a factor of four, and reservoir pressures began a period of steep decline. These changes caused a temporary three-fold increase in the tilt rate. The tilt rate became stable in 1993 and was about 40% lower than that measured in 1991-1992, but still greater than the rates measured during 1985-1990. Data from the
Luais, Béatrice; Le Carlier de Veslud, Christian; Géraud, Yves; Gauthier-Lafaye, François
2009-05-01
We have carried out a comparative Rb-Sr, Sm-Nd and Lu-Hf isotopic study of a progressively deformed hercynian leucogranite from the French Massif Central, belonging to the La Marche ductile shear zone, in order to investigate the respective perturbation of these geochronometers with fluid induced deformation. The one-meter wide outcrop presents a strongly deformed and mylonitized zone at the center, and an asymmetric deformation pattern with a higher deformation gradient on the northern side of the zone. Ten samples have been carefully collected every 10 cm North and South away from the strongest deformed mylonitic zone. They have been analyzed for a complete major, trace element data set, oxygen isotopes, Rb-Sr, Sm-Nd and Lu-Hf isotopic systematics. We show that most of major and trace elements except SiO 2, alkaline elements (K 2O, Rb), and some metal transition elements (Cu), are progressively depleted with increasing deformation. This depletion includes REE + Y, but also HFS elements (Ti, Hf, Zr, Nb) which are commonly considered as immobile elements during upper level processes. Variations in elemental ratios with deformation, e.g. decrease in LREE/MREE- HREE, Nd/Hf, Th/Sr, increase in Rb/Sr, U/Th and constant Sr/Nd, lead to propose the following order of element mobility: U ≫ Th > Sr = Nd ≫ Hf + HREE. We conclude in agreement with previous tectonic and metallogenic studies that trace element patterns across the shear zone result from circulation of oxidizing F-rich hydrothermal fluids associated with deformation. A temperature of the fluid of 470-480 °C can be deduced from the δ 18O equilibrium between quartz-muscovite pairs. Elemental fractionation induces perturbation of the Rb-Sr geochronometer. The well-defined 87Rb/ 86Sr- 87Sr/ 86Sr correlation gives an apparent age of 294 ± 19 Ma, slightly younger than the 323 ± 4 Ma age of leucogranites in this area. This apparent age is interpreted as dating event of intense deformation and fluid circulation
Both, C.; Robinson, R.A.; Van der Jeugd, H.P.
2012-01-01
Long-distance dispersal can potentially have important consequences for evolutionary change, but is difficult to quantify. We present quantitative estimates of natal dispersal between the UK and the Netherlands in a long-distance migratory bird, the pied flycatcher. Due to over 90 000 individual rin
Wang, X
2006-02-01
Energy dispersive X-ray microanalysis (EDXMA) is a widely used tool employed to detect elemental composition and its spatial distribution in a sample without causing damage. Charcoalified cytoplasm is a new type of fossil material that came to people's attention only recently. In this paper, EDXMA is used for the first time to detect the spatial elemental distribution in charcoalified cytoplasm of two fossil plants that are more than 100 million years old. The results demonstrate certain elemental distribution patterns within charcoalified cytoplasm and the surrounding cell walls. Based on the results from cytological studies of extant material, the heterogeneous spatial elemental distribution within the charcoalified cytoplasm has the potential to be related to the maturation of cells, the presence of certain organelles, and the physiology of these organelles. This is the first chemical signal detected in cytoplasm residue that can possibly be related to plant physiology. This paves the way for further research on fossil cytoplasm, which will better our understanding on the physiology of fossil plants.
Directory of Open Access Journals (Sweden)
Filipe Pereira
Full Text Available The pinewood nematode, Bursaphelenchus xylophilus, is one of the greatest threats to coniferous forests worldwide, causing severe ecological damage and economic loss. The biology of B. xylophilus is similar to that of its closest relative, B. mucronatus, as both species share food resources and insect vectors, and have very similar morphological characteristics, although little pathogenicity to conifers has been associated with B. mucronatus. Using both nuclear and mitochondrial DNA markers, we show that B. xylophilus and B. mucronatus form distinct phylogenetic groups with contrasting phylogeographic patterns. B. xylophilus presents lower levels of intraspecific diversity than B. mucronatus, as expected for a species that evolved relatively recently through geographical or reproductive isolation. Genetic diversity was particularly low in recently colonised areas, such as in southwestern Europe. By contrast, B. mucronatus displays high levels of genetic diversity and two well-differentiated clades in both mitochondrial and nuclear DNA phylogenies. The lack of correlation between genetic and geographic distances in B. mucronatus suggests intense gene flow among distant regions, a phenomenon that may have remained unnoticed due to the reduced pathogenicity of the species. Overall, our findings suggest that B. xylophilus and B. mucronatus have different demographic histories despite their morphological resemblance and ecological overlap. These results suggest that Bursaphelenchus species are a valuable model for understanding the dispersion of invasive species and the risks posed to native biodiversity and ecosystems.
Active faulting on the Ninetyeast Ridge and its relation to deformation of the Indo-Australian plate
Digital Repository Service at National Institute of Oceanography (India)
Sager, W.W.; Bull, J.M.; Krishna, K.S.
extents are poorly defined. New multichannel seismic reflection profiles image active faults along the entire length of the NER and show spatial changes in the style of deformation along the ridge. The northern NER (0°N–5°N) displays transpressional motion...
Heuret, A.; Funiciello, F.; Faccenna, C.; Lallemand, S.
2005-12-01
3-D laboratory models have been performed in order to investigate the way plates kinematics (subducting and overriding plate absolute motions and the resulting plate convergence rate) influences the geometry of the slab and the overriding plate deformation in subduction zones. In the experiments a viscous plate of silicone (subducting plate) is pushed beneath another plate, which is itself pushed toward or pulled away from the trench (overriding plate), and sinks into a viscous layer of glucose syrup (upper mantle). The subducting and overriding plate velocities explored the variability field of natural subduction plates kinematics. The overriding plate motion exerts a primary role in the control of slab geometries and overriding plate deformation rates. The experiments have revealed two different subduction behaviours: (Style I) the overriding plate moves toward the trench and shortens at high rates, the slab is flat and deflected when reaching the bottom of the box in a forward direction; (Style II) the overriding plates moves away from the trench and shortens at low rates the slab is steep and deflected on the box bottom in a backward direction. To a lesser extent, increasing subducting plate motion is associated to increasing slab dips and overriding plate shortening. Slab geometry and overriding plate deformation are less sensitive to the overall plate convergence rate. These laboratory models behaviours are consistent with statistical analysis performed on natural subduction zones, and enlighten the first order control exerted by the overriding plate absolute motion, on the geometry adopted by the slab and the way the overriding plate deforms.
Symplectic Deformations of Integrable Field Theories and AdS/CFT
Hollowood, Timothy J
2014-01-01
Relativistic integrable field theories like the sine-Gordon equation have an infinite set of conserved charges. In a light-front formalism these conserved charges are closely related to the integrable modified KdV hierarchy at the classical level. The latter hierarchy admits a family of symplectic structures which we argue can be viewed as deformations of the relativistic sine-Gordon symplectic structure. These deformed theories are integrable but no longer relativistic and the basic excitations of the theory, the solitons, have an interesting non-relativistic dispersion relation that in a certain limit becomes the dispersion relation of dyonic giant magnons of string theory in the AdS/CFT correspondence. We argue that the deformed classical theories can be lifted to quantum theories when the sine-Gordon theory is embedded in a larger theory that describes the string world-sheet sigma model in AdS(5)xS(5).
Symplectic deformations of integrable field theories and AdS/CFT
Energy Technology Data Exchange (ETDEWEB)
Hollowood, Timothy J., E-mail: t.hollowood@swansea.ac.uk [Department of Physics, Swansea University, Swansea, SA2 8PP (United Kingdom); Miramontes, J. Luis, E-mail: jluis.miramontes@usc.es [Departamento de Física de Partículas and IGFAE, Universidad de Santiago de Compostela, 15782 Santiago de Compostela (Spain)
2014-12-12
Relativistic integrable field theories like the sine-Gordon equation have an infinite set of conserved charges. In a light-front formalism these conserved charges are closely related to the integrable modified KdV hierarchy at the classical level. The latter hierarchy admits a family of symplectic structures which we argue can be viewed as deformations of the relativistic sine-Gordon symplectic structure. These deformed theories are integrable but no longer relativistic and the basic excitations of the theory, the solitons, have an interesting non-relativistic dispersion relation that in a certain limit becomes the dispersion relation of dyonic giant magnons of string theory in the AdS/CFT correspondence. We argue that the deformed classical theories can be lifted to quantum theories when the sine-Gordon theory is embedded in a larger theory that describes the string world-sheet sigma model in AdS{sub 5}×S{sup 5}.
DEFF Research Database (Denmark)
Pugliese, Lorenzo; Poulsen, Tjalfe; Straface, Salvatore
2013-01-01
data. This paper evaluates the possibility for estimating solute dispersion based on gas dispersion measurements. Breakthrough measurements were carried out at different fluid velocities (covering the same range in Reynolds number), using O2 and NaCl as gas and solute tracers, respectively. Three...... different, granular porous materials were used: (1) crushed granite (very angular particles), (2) gravel (particles of intermediate roundness) and (3) Leca® (almost spherical particles). For each material, 21 different particle size fractions were used. Gas and solute dispersion coefficients were determined...
Iizuka, Hideo; Fan, Shanhui
2016-11-01
We provide a detailed discussion of the use of coupled mode theory to describe near-field heat transfer. We consider a simple physical model system of coupled harmonic oscillators with each oscillator maintaining at a different temperature, where heat transfer between the oscillators can be analytically treated from first-principles using the Newton's equation and the fluctuation dissipation theorem. Applying a slowly varying envelope approximation to the Newton's equation, we derive a coupled mode theory formalism. We then apply this coupled mode theory formalism in the study of the near-field heat transfer between either silicon carbide plates or between two graphene sheets. The coupled mode theory provides a quantitative link between the dispersion relation of the coupled system and the heat transfer, and agrees with exact numerical results over all range of wavevectors. To obtain such complete agreement, the key observation here is that one should include the frequency shift, that is, the frequency of the individual mode used in the coupled mode theory should be different from the frequency of the mode of an isolated structure. Finally, we show that the coupled mode theory can be applied even when more than two modes are involved in the heat transfer. As an example, we extend our formalism to the near-field heat transfer in a four-layer graphene structure.
Michelitsch, Thomas M; Nicolleau, Franck C G A; Nowakowski, Andrzej F; Derogar, Shahram
2009-01-01
Many systems in nature have arborescent and bifurcated structures such as trees, fern, snails, lungs, the blood vessel system, etc. and look self-similar over a wide range of scales. Which are the mechanical and dynamic properties that evolution has optimized by choosing self-similarity? How can we describe the mechanics of self-similar structures in the static and dynamic framework? Physical systems with self-similarity as a symmetry property require the introduction of non-local particle-particle interactions and a (quasi-) continuous distribution of mass. We construct self-similar functions and linear operators such as a self-similar variant of the Laplacian and of the D'Alembertian wave operator. The obtained self-similar linear wave equation describes the dynamics of a quasi-continuous linear chain of infinite length with a spatially self-similar distribution of nonlocal inter-particle springs. The self-similarity of the nonlocal harmonic particle-particle interactions results in a dispersion relation of...
Shaltout, Abdallah A.; Moharram, Mohammed A.; Mostafa, Nasser Y.
2012-01-01
This work is the first attempt to quantify trace elements in the Catha edulis plant (Khat) with a fundamental parameter approach. C. edulis is a famous drug plant in east Africa and Arabian Peninsula. We have previously confirmed that hydroxyapatite represents one of the main inorganic compounds in the leaves and stalks of C. edulis. Comparable plant leaves from basil, mint and green tea were included in the present investigation as well as trifolium leaves were included as a non-related plant. The elemental analyses of the plants were done by Wavelength Dispersive X-Ray Fluorescence (WDXRF) spectroscopy. Standard-less quantitative WDXRF analysis was carried out based on the fundamental parameter approaches. According to the standard-less analysis algorithms, there is an essential need for an accurate determination of the amount of organic material in the sample. A new approach, based on the differential thermal analysis, was successfully used for the organic material determination. The obtained results based on this approach were in a good agreement with the commonly used methods. Depending on the developed method, quantitative analysis results of eighteen elements including; Al, Br, Ca, Cl, Cu, Fe, K, Na, Ni, Mg, Mn, P, Rb, S, Si, Sr, Ti and Zn were obtained for each plant. The results of the certified reference materials of green tea (NCSZC73014, China National Analysis Center for Iron and Steel, Beijing, China) confirmed the validity of the proposed method.
Low-cycle fatigue of dispersion-strengthened copper
Energy Technology Data Exchange (ETDEWEB)
Robles, J. (Clorox Co., Pleasanton, CA (United States)); Anderson, K.R.; Groza, J.R.; Gibeling, J.C. (Univ. of California, Davis, CA (United States))
1994-10-01
The cyclic deformation behavior of a dispersion-strengthened copper alloy, GlidCop Al-15, has been studied at plastic strain amplitudes in the range 0.1 pct [<=] [Delta][var epsilon][sub p]/2 [<=] 0.8 pct. Compared to pure polycrystalline copper, the dispersion-strengthened material exhibits a relatively stable cyclic response as a consequence of the dislocation substructures inherited from prior processing and stabilized by the Al[sub 2]O[sub 3] particles. These dislocation structures remain largely unaltered during the course of deformation; hence, they do not reveal any of the features classically associated with copper tested in fatigue. At low amplitudes, the fatigue lifetimes of the dispersion-strengthened copper and the base alloy are similar; however, the former is more susceptible to cracking at stress concentrations because of its substantially greater strength. This similarity in fatigue life-times is a consequence of the dispersal of both deformation and damage accumulation by the fine grain size and dislocation/particle interactions in the GlidCop alloy. The operation of these mechanisms is reflected in the fine surface slip markings and rough fracture surface features for this material.
Low-frequency dielectric dispersion of bacterial cell suspensions.
Asami, Koji
2014-07-01
Dielectric spectra of Escherichia coli cells suspended in 0.1-10 mM NaCl were measured over a frequency range of 10 Hz to 10 MHz. Low-frequency dielectric dispersion, so-called the α-dispersion, was found below 10 kHz in addition to the β-dispersion, due to interfacial polarization, appearing above 100 kHz. When the cells were killed by heating at 60°C for 30 min, the β-dispersion disappeared completely, whereas the α-dispersion was little influenced. This suggests that the plasma (or inner) membranes of the dead cells are no longer the permeability barrier to small ions, and that the α-dispersion is not related to the membrane potential due to selective membrane permeability of ions. The intensity of the α-dispersion depended on both of the pH and ionic strength of the external medium, supporting the model that the α-dispersion results from the deformation of the ion clouds formed outside and inside the cell wall containing charged residues. Copyright © 2014 Elsevier B.V. All rights reserved.
Wojciechowski, Wadim; Molka, Adrian; Tabor, Zbisław
2016-03-01
Measurement of the deformation of the lower limbs in the current standard full-limb X-rays images presents significant challenges to radiologists and orthopedists. The precision of these measurements is deteriorated because of inexact positioning of the leg during image acquisition, problems with selecting reliable anatomical landmarks in projective X-ray images, and inevitable errors of manual measurements. The influence of the random errors resulting from the last two factors on the precision of the measurement can be reduced if an automated measurement method is used instead of a manual one. In the paper a framework for an automated measurement of various metric and angular quantities used in the description of the lower extremity deformation in full-limb frontal X-ray images is described. The results of automated measurements are compared with manual measurements. These results demonstrate that an automated method can be a valuable alternative to the manual measurements.
Lux, S E; John, K M; Ukena, T E
1978-03-01
We measured spectrin "extractability" in erythrocytes which were metabolically depleted by incubation at 37 degrees C in plasma or glucose-free buffers. Membranes were extracted with 1 mM EDTA (pH 8, 40 h, 4 degrees C) and analyzed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. This procedure solubilized 85--90% of the spectrin, actin, and residual hemoglobin from ghosts of fresh erythrocytes. In incubated erythrocytes, inextractable spectrin rapidly accumulated when ATP concentrations fell below 0--15% of normal. In severely depleted cells, 60--90% of the total ghost spectrin became inextractable. Inextractability was not abolished by physically disrupting the ghost before extraction, but was reversed when erythrocyte ATP was replenished with adenosine. The accumulation of inextractable spectrin correlated temporally with the increase in apparent membrane deformability and the increases in erythrocyte vicosity, calcium content, sodium gain, and potassium loss characteristic of ATP-depleted erythrocytes. No change in integral membrane protein topography (assessed by the distribution of intramembranous particles and concanavalin A surface-binding sites) was detected in depleted cells. Analogous changes were observed in erythrocytes exposed to extremes of pH and temperature. When the pH in the erythrocyte interior fell below 5.5, a pH where spectrin was aggregated and isoelectrically precipitated, erythrocyte and ghost viscosity increased coincident with a marked decrease in spectrin extractability. Similarly above 49 degrees C, a temperature where spectrin was denatured and precipitated, erythrocyte viscosity rose as inextractable spectrin accumulated. These observations provide direct evidence of a change in the physical state of spectrin associated with a change in erythrocyte shape and deformability. They support the concept that erythrocyte shape and deformability are largely determined by the shape and deformability of the spectrin
Directory of Open Access Journals (Sweden)
W. Birmili
2009-04-01
Full Text Available Atmospheric particle number size distributions of airborne particles (diameter range 10–500 nm were collected over ten weeks at three sites in the vicinity of the A100 urban motorway in Berlin, Germany. The A100 carries about 180 000 vehicles on a weekday. The roadside particle distributions showed a number maximum between 20 and 60 nm clearly related to the motorway emissions. The average total number concentration at roadside was 28 000 cm^{−3} with a total range of 1200–168 000 cm^{−3}. At distances of 80 and 400 m from the motorway the concentrations decreased to mean levels of 11 000 and 9000 cm^{−3}, respectively. An obstacle-resolving dispersion model was applied to simulate the 3-D flow field and traffic tracer transport in the urban environment around the motorway. By inverse modelling, vehicle emission factors were derived that are representative of a fleet with a relative share of 6% lorry-like vehicles, and driving at a speed of 80 km h^{−1}. Three different calculation approaches were compared, which differ in the choice of the experimental winds driving the flow simulation. The average emission factor per vehicle was 2.1 (±0.2 · 10^{14} km^{−1} for particle number and 0.077 (±0.01 · 10^{14} cm^{3} km^{−1} for particle volume. Regression analysis suggested that lorry-like vehicles emit 123 (±28 times more particle number than passenger car-like vehicles, and lorry-like vehicles account for about 91% of particulate number emissions on weekdays. Our work highlights the increasing applicability of 3-D flow models in urban microscale environments and their usefulness for determining traffic emission factors.
Deformity - contracture ... Contracture can be caused by any of the following: Brain and nervous system disorders, such as cerebral ... Follow your health care provider's instructions for treating contracture at home. Treatments may include: Doing exercises and ...
Energy Technology Data Exchange (ETDEWEB)
Louis, L.
2003-10-15
From diagenesis to tectonic stress induced deformation, rock microstructures always present some anisotropy associated with a preferential orientation, shape or spatial arrangement of its constituents. Considering the consequences anisotropy has on directional transport properties and compliance, as the geological history it carries, this approach has received a particular attention in numerous works. In this work, the microstructural features of various sedimentary rocks were investigated through direct observations and laboratory measurements in naturally deformed and undeformed blocks, samples being considered as effective media. All investigated samples were found to be anisotropic with respect to the physical properties we measured (i.e. ultrasonic P-wave velocity, magnetic susceptibility, electrical conductivity). Considering that P-wave velocities can be described by a second order tensor, we applied to the velocity data the same inversion procedure as the one routinely used in magnetic studies, which provided an efficient tool to estimate and compare these 3D anisotropies with respect to the original sample geographical position. In each case, we tried to identify as thoroughly as possible the microstructural source of the observed anisotropies, first by the mean of existing models, then through direct observations (optic and electronic microscopy). Depending on the rock investigated, anisotropy was found to be controlled by pore shape, intergranular contact distribution, preferentially oriented microcracks interacting with compaction pattern or pressure solution cleavages interacting with each other. The net result of this work is that P-wave velocity anisotropy can express the interaction between different microstructural features as well as their evolution during deformation. (author)
Stevens, Jan
2003-01-01
These notes deal with deformation theory of complex analytic singularities and related objects. The first part treats general theory. The central notion is that of versal deformation in several variants. The theory is developed both in an abstract way and in a concrete way suitable for computations. The second part deals with more specific problems, specially on curves and surfaces. Smoothings of singularities are the main concern. Examples are spread throughout the text.
Institute of Scientific and Technical Information of China (English)
DU Yuansheng; XU Yajun; YANG Jianghai
2008-01-01
Devonian in the North Qilian orogenic belt and Hexi Corridor developed terrestrial molasse of later stage of foreland basin caused by collision between the North China plate and Qaidam microplate. The foreland basin triggered a intense earthquake, and formed seismites and earthquake- related soft-sediment deformation. The soft-sediment deformation structures of Devonian in the eastern North Qilian Mts. consist of seismo-cracks, sandstone dykes, syn-depositional faults, microfolds (micro-corrugated lamination), fluidized veins, load casts, flame structures, pillow structures and brecciation. The seismo-cracks, syn-depositional faults and microfolds are cracks, faults and folds formed directly by oscillation of earthquake. The seismic dykes formed by sediment instilling into seismic cracks. Fluidized veins were made by instilling into the seismo-fissures of the fluidized sands. The load casts, flame structures and pillow structures were formed by sinking and instilling caused from oscillation of earthquake along the face between sandy and muddy beds. The brecciation resulted from the oscillation of earthquake and cracking of sedimentary layers. The seismites and soft-sediment deformations in Devonian triggered the earthquake related to tectonic activities during the orogeny and uplift of North Qilian Mts.
Reversibility of Lpo in Olivine during Deformation at High Pressure
Li, L.; Weidner, D. J.
2014-12-01
Olivine texture has been reported as an important contributor to the seismic anisotropy in the upper mantle. Experimental studies of deformation of olivine have also shown flow-driven lattice preferred orientation. In this study, we focus on in situ control and monitoring of LPO formation of olivine using synchrotron X-ray radiation coupled with DDIA multi-anvil deformation device. Using an energy-dispersive X-ray coupled a 10-element SSD detector; we apply a sinusoidal stress on the sample, which allows identification of growth of LPO in the specimen with relative robust signal even with small strain fields. Our data show palpable correlations among stress, strain and LPO as well as the variations among sub-grains marked by individual (hkl). This study is to demonstrate the versatile functions of X-ray for characterizing the deformation study of minerals.
Directory of Open Access Journals (Sweden)
Pelaez J. R.
2012-12-01
Full Text Available The long-standing puzzle in the parameters of the f0(500, as well as the f0(980, is finally being settled [1] thanks to precise dispersive analyses carried out during the last years. Here we report on our very recent dispersive data analysis which allowed for a precise and model independent determination of the amplitudes for the S, P, D and F waves [2–4]. The analytic continuation of once subtracted dispersion relations for the S0 wave to the complex energy plane leads to very precise results for the f0(500 pole: √spole = 457-13+14 - i279-7+11 MeV and for the f0(980 pole: √spole = 996 ± 7 - i25-6+10 MeV.
Energy Technology Data Exchange (ETDEWEB)
Shaltout, Abdallah A., E-mail: shaltout_a@hotmail.com [Spectroscopy Department, Physics Division, National Research Center, El Behooth Str., 12622 Dokki, Cairo (Egypt); Faculty of science, Taif University, 21974 Taif, P.O. Box 888 (Saudi Arabia); Moharram, Mohammed A. [Spectroscopy Department, Physics Division, National Research Center, El Behooth Str., 12622 Dokki, Cairo (Egypt); Mostafa, Nasser Y. [Faculty of science, Taif University, 21974 Taif, P.O. Box 888 (Saudi Arabia); Chemistry Department, Faculty of Science, Suez Canal University, Ismailia (Egypt)
2012-01-15
This work is the first attempt to quantify trace elements in the Catha edulis plant (Khat) with a fundamental parameter approach. C. edulis is a famous drug plant in east Africa and Arabian Peninsula. We have previously confirmed that hydroxyapatite represents one of the main inorganic compounds in the leaves and stalks of C. edulis. Comparable plant leaves from basil, mint and green tea were included in the present investigation as well as trifolium leaves were included as a non-related plant. The elemental analyses of the plants were done by Wavelength Dispersive X-Ray Fluorescence (WDXRF) spectroscopy. Standard-less quantitative WDXRF analysis was carried out based on the fundamental parameter approaches. According to the standard-less analysis algorithms, there is an essential need for an accurate determination of the amount of organic material in the sample. A new approach, based on the differential thermal analysis, was successfully used for the organic material determination. The obtained results based on this approach were in a good agreement with the commonly used methods. Depending on the developed method, quantitative analysis results of eighteen elements including; Al, Br, Ca, Cl, Cu, Fe, K, Na, Ni, Mg, Mn, P, Rb, S, Si, Sr, Ti and Zn were obtained for each plant. The results of the certified reference materials of green tea (NCSZC73014, China National Analysis Center for Iron and Steel, Beijing, China) confirmed the validity of the proposed method. - Highlights: Black-Right-Pointing-Pointer Quantitative analysis of Catha edulis was carried out using standardless WDXRF. Black-Right-Pointing-Pointer Differential thermal analysis was used for determination of the loss of ignition. Black-Right-Pointing-Pointer The existence of hydroxyapatite in Catha edulis plant has been confirmed. Black-Right-Pointing-Pointer The CRM results confirmed the validity of the developed method.
Deformation of second and third quantization
Faizal, Mir
2015-03-01
In this paper, we will deform the second and third quantized theories by deforming the canonical commutation relations in such a way that they become consistent with the generalized uncertainty principle. Thus, we will first deform the second quantized commutator and obtain a deformed version of the Wheeler-DeWitt equation. Then we will further deform the third quantized theory by deforming the third quantized canonical commutation relation. This way we will obtain a deformed version of the third quantized theory for the multiverse.
Deformation of Second and Third Quantization
Faizal, Mir
2015-01-01
In this paper, we will deform the second and third quantized theories by deforming the canonical commutation relations in such a way that they become consistent with the generalized uncertainty principle. Thus, we will first deform the second quantized commutator and obtain a deformed version of the Wheeler-DeWitt equation. Then we will further deform the third quantized theory by deforming the third quantized canonical commutation relation. This way we will obtain a deformed version of the third quantized theory for the multiverse.
Girder deformation related phase errors on the undulators for the European X-Ray Free Electron Laser
Directory of Open Access Journals (Sweden)
Yuhui Li
2015-06-01
Full Text Available In long gap tunable undulators, strong magnetic forces always lead to some amount of gap-dependent girder deformation and resulting gap-dependent phase errors. For the undulators for the European XFEL, this problem has been investigated thoroughly and quantitatively. Using the different gap dependencies of suitable shims and pole height tuning, a method is presented which can be applied to reduce the overall gap dependence of the phase error if needed. It is exemplified by tuning one of the undulator segments for the European X-Ray Free Electron Laser back to specs.
Ibáñez-Mejía, Juan C; Klessen, Ralf S; Baczynski, Christian
2015-01-01
Molecular cloud observations show that clouds have non-thermal velocity dispersions that scale with the cloud size as $\\sigma\\propto R^{1/2}$ at constant surface density, and for varying surface density scale with both the cloud`s size and surface density, $\\sigma^2 \\propto R \\Sigma$. The energy source driving these chaotic motions remains poorly understood. We describe the velocity dispersions observed in a cloud population formed in a kiloparsec-scale numerical simulation of a magnetized, supernova-driven, self-gravitating, interstellar medium, including diffuse heating and radiative cooling. We compare the relationships between velocity dispersion, size, and surface density measured in the simulated cloud population to those found in observations of Galactic molecular clouds. We find that external supernova explosions can not drive turbulent motions of the observed magnitudes within dense clouds. On the other hand, self-gravity also induces non-thermal motions as gravitationally bound clouds begin to colla...
Unga, Johan; Tajarobi, Farhad; Norder, Ove; Frenning, Göran; Larsson, Anette
2009-10-01
The solid state behaviour of polyethylene glycol 4000 (PEG 4000) and dispersions of a homologous series of parabens (methyl- (MP), ethyl- (EP), propyl- (PP) and butyl- (BP)) were examined and compared to the paraben solubility in liquid PEG 400. Dispersions were prepared by co-melting different amounts of paraben (5-80% (w/w)) and PEG 4000 and were studied using a combination of differential scanning calorimetry (DSC) and small and wide angle X-ray diffraction (SAXD/WAXD). Depending on the concentration of parabens in the dispersions, DSC showed melting peaks from folded and unfolded forms of PEG, a eutectic melting and melting of pure parabens. The fraction of folded PEG increased and the melting temperatures of both PEG forms decreased with increasing paraben content. In an apparent phase diagram of PP-PEG dispersions a eutectic mixture appeared above 5% PP. In addition, a melting peak corresponding to the paraben appeared for dispersion containing more than 60% PP. Similar phase diagrams were shown for the other parabens. The SAXD data and a 1D correlation function analysis revealed that MP and BP were incorporated into the amorphous domains of the lamellae of solid PEG to a higher degree than EP and PP. In addition, the lamellae thickness of PEG and the fraction of amorphous domains increased more for MP and BP compared to EP and PP. BP showed the highest solubility of the parabens followed by MP, EP and PP in both liquid and solid PEG. Furthermore, the thickness of the amorphous domains of the PEG in the different parabens-PEG dispersions could be correlated to the solubility in liquid PEG 400.
Micheuz, P.; Kurz, W.; Ferre, E. C.
2015-12-01
IODP Expedition 352 aimed to drill through the entire volcanic sequence of the Bonin fore arc. Four sites were drilled, two on the outer fore arc and two on the upper trench slope. Analysis of structures within drill cores, combined with borehole and site survey seismic data, indicates that tectonic deformation in the outer Izu-Bonin-Mariana fore arc is mainly post-magmatic, associated with the development of syn-tectonic sedimentary basins. Within the magmatic basement, deformation was accommodated by shear along cataclastic fault zones, and the formation of tension fractures, hybrid (tension and shear) fractures, and shear fractures. Veins commonly form by mineral filling of tension or hybrid fractures and, generally, show no or limited observable macroscale displacement along the fracture plane. The vein filling generally consists of (Low Mg-) calcite and/or various types of zeolite as well as clay. Vein frequency varies with depth but does not seem to correlate with the proximity of faults. This may indicate that these veins are genetically related to hydrothermal activity taking place shortly after magma cooling. Host-rock fragments are commonly embedded within precipitated vein material pointing to a high fluid pressure. Vein thickness varies from < 1 mm up to 15 mm. The wider veins appear to have formed in incremental steps of extension. Calcite veins tend to be purely dilational at shallow depths, but gradually evolve towards oblique tensional veins at depth, as shown by the growth of stretched calcite and/or zeolites (idiomorphic and/or stretched) with respect to vein margins. With increasing depth, the calcite grains exhibit deformation microstructures more frequently than at shallower core intervals. These microstructures include thin twinning (type I twins), increasing in width with depth (type I and type II twins), curved twins, and subgrain boundaries indicative of incipient plastic deformation.
Energy Technology Data Exchange (ETDEWEB)
Cappa, F.; Rutqvist, J.; Yamamoto, K.
2009-05-15
In Matsushiro, central Japan, a series of more than 700,000 earthquakes occurred over a 2-year period (1965-1967) associated with a strike-slip faulting sequence. This swarm of earthquakes resulted in ground surface deformations, cracking of the topsoil, and enhanced spring-outflows with changes in chemical compositions as well as carbon dioxide (CO{sub 2}) degassing. Previous investigations of the Matsushiro earthquake swarm have suggested that migration of underground water and/or magma may have had a strong influence on the swarm activity. In this study, employing coupled multiphase flow and geomechanical modelling, we show that observed crustal deformations and seismicity can have been driven by upwelling of deep CO{sub 2}-rich fluids around the intersection of two fault zones - the regional East Nagano earthquake fault and the conjugate Matsushiro fault. We show that the observed spatial evolution of seismicity along the two faults and magnitudes surface uplift, are convincingly explained by a few MPa of pressurization from the upwelling fluid within the critically stressed crust - a crust under a strike-slip stress regime near the frictional strength limit. Our analysis indicates that the most important cause for triggering of seismicity during the Matsushiro swarm was the fluid pressurization with the associated reduction in effective stress and strength in fault segments that were initially near critically stressed for shear failure. Moreover, our analysis indicates that a two order of magnitude permeability enhancement in ruptured fault segments may be necessary to match the observed time evolution of surface uplift. We conclude that our hydromechanical modelling study of the Matsushiro earthquake swarm shows a clear connection between earthquake rupture, deformation, stress, and permeability changes, as well as large-scale fluid flow related to degassing of CO{sub 2} in the shallow seismogenic crust. Thus, our study provides further evidence of the
Frequency of angular deformities of the knee joint of school children in relation to sex and ages
Directory of Open Access Journals (Sweden)
Jovović Veselin
2012-01-01
Full Text Available The subject of this research is the angular deformity of the knee joint of younger adolescents. The aim of the research was to measure the frequency, structure and size of static disorders of the knee joint in the frontal plane, depending on sex and calendar age. The sample comprised 251 respondents, primary school pupils, 10, 12 and 14 years of age. This is one of the most sensitive periods in the development of young pupils. It is characterized by a sudden change in the dynamics of living and also by an increased occurrence of postural disorders (Radisavljević, 2001; Kosinac, 2005. To estimate the status of the knee joint, we selected two variables: X-shaped legs (Genua valga and O-shaped legs (Genua vara. Variables for estimating the status and structure of existing deformities were subjected to the somatoscopy method and to the test of 'voluntary' muscle contraction (Radisavljević, 2001; Jovović, 1999. The greatest angular frequency of knee joint disorders is at the age of 12 for girls and at the age of 14 for boys. O-shaped legs are present in a slightly higher percentage in both sexes and all three age groups. The greatest frequencies of deviations from normal are functional disorders, which can be successfully corrected in a large extent by using active and passive measures.
Institute of Scientific and Technical Information of China (English)
LiWei; WeiYan-Yu; XieHong-Quan; LiuSheng-Gang; GongMa-Li
2003-01-01
A general dispersion equation of a partially filled plasma corrugated waveguide immersed in a finite magnetic field is presented.When the guiding magnet B0→∞ or 0, this equation can be reduced to the results obtained in previous works.
Li, Rukang; Wang, Lirong; Wang, Xiaoyang; Wang, Guiling; Chen, Chuangtian
2016-12-20
KBesub>2sub>BOsub>3sub>Fsub>2sub> (KBBF) is the only nonlinear optical crystal available to generate deep-ultraviolet (DUV) laser output by direct harmonic generation. High-precision refractive indices, including in the DUV region, were measured, and starting from a double resonance model of polarizability, new dispersion relations of the refractive indices were deduced from the measured data. The predicted phase matching angles for second-harmonic generation down to 165 nm from the new relations agree well with the previous reported values. Moreover, the new dispersion relations show superior results in an even shorter wavelength range, giving perfectly calculated phase matching angles for fifth-harmonic generation down to as short as 149.8 nm.
DEFF Research Database (Denmark)
Hansen, N.; Huang, X.; Hughes, D.A.
2004-01-01
Microstructural characterization and modeling has shown that a variety of metals deformed by different thermomechanical processes follows a general path of grain subdivision, by dislocation boundaries and high angle boundaries. This subdivision has been observed to very small structural scales...... of the order of 10 nm, produced by deformation under large sliding loads. Limits to the evolution of microstructural parameters during monotonic loading have been investigated based on a characterization by transmission electron microscopy. Such limits have been observed at an equivalent strain of about 10...
Fallah-Shorshani, Masoud; Shekarrizfard, Maryam; Hatzopoulou, Marianne
2017-10-01
Dispersion of road transport emissions in urban metropolitan areas is typically simulated using Gaussian models that ignore the turbulence and drag induced by buildings, which are especially relevant for areas with dense downtown cores. To consider the effect of buildings, street canyon models are used but often at the level of single urban corridors and small road networks. In this paper, we compare and validate two dispersion models with widely varying algorithms, across a modelling domain consisting of the City of Montreal, Canada accounting for emissions of more 40,000 roads. The first dispersion model is based on flow decomposition into the urban canopy sub-flow as well as overlying airflow. It takes into account the specific height and geometry of buildings along each road. The second model is a Gaussian puff dispersion model, which handles complex terrain and incorporates three-dimensional meteorology, but accounts for buildings only through variations in the initial vertical mixing coefficient. Validation against surface observations indicated that both models under-predicted measured concentrations. Average weekly exposure surfaces derived from both models were found to be reasonably correlated (r = 0.8) although the Gaussian dispersion model tended to underestimate concentrations around the roadways compared to the street canyon model. In addition, both models were used to estimate exposures of a representative sample of the Montreal population composed of 1319 individuals. Large differences were noted whereby exposures derived from the Gaussian puff model were significantly lower than exposures derived from the street canyon model, an expected result considering the concentration of population around roadways. These differences have large implications for the analyses of health effects associated with NO2 exposure.
Directory of Open Access Journals (Sweden)
Trevor T Bringloe
Full Text Available Dispersal, the movement of an individual away from its natal or breeding ground, has been studied extensively in birds and mammals to understand the costs and benefits of movement behavior. Whether or not invertebrates disperse in response to such attributes as habitat quality or density of conspecifics remains uncertain, due in part to the difficulties in marking and recapturing invertebrates. In the upper Bay of Fundy, Canada, the intertidal amphipod Corophium volutator swims at night around the new or full moon. Furthermore, this species is regionally widespread across a large spatial scale with site-to-site variation in population structure. Such variation provides a backdrop against which biological determinants of dispersal can be investigated. We conducted a large-scale study at nine mudflats, and used swimmer density, sampled using stationary plankton nets, as a proxy for dispersing individuals. We also sampled mud residents using sediment cores over 3 sampling rounds (20-28 June, 10-17 July, 2-11 August 2010. Density of swimmers was most variable at the largest spatial scales, indicating important population-level variation. The smallest juveniles and large juveniles or small adults (particularly females were consistently overrepresented as swimmers. Small juveniles swam at most times and locations, whereas swimming of young females decreased with increasing mud presence of young males, and swimming of large juveniles decreased with increasing mud presence of adults. Swimming in most stages increased with density of mud residents; however, proportionally less swimming occurred as total mud resident density increased. We suggest small juveniles move in search of C. volutator aggregations which possibly act as a proxy for better habitat. We also suggest large juveniles and small adults move if potential mates are limiting. Future studies can use sampling designs over large spatial scales with varying population structure to help
Menant, Armel; Jolivet, Laurent; Guillou-Frottier, Laurent; Sternai, Pietro; Gerya, Taras
2016-04-01
Active convergent margins are the locus of various large-scale lithospheric processes including subduction, back-arc opening, lithospheric delamination, slab tearing and break-off. Coexistence of such processes results in a complex lithospheric deformation pattern through the rheological stratification of the overriding lithosphere. In this context, another major feature is the development of an intense arc- and back-arc-related magmatism whose effects on lithospheric deformation by rheological weakening are largely unknown. Quantifying this magma-related weakening effect and integrating the three-dimensional (3D) natural complexity of subduction system is however challenging because of the large number of physico-chemical processes involved (e.g. heat advection, dehydration of subducted material, partial melting of the mantle wedge). We present here a set of 3D high-resolution petrological and thermo-mechanical numerical experiments to assess the role of low-viscosity magmatic phases on lithospheric deformation associated with coeval oceanic and continental subduction, followed by slab retreat and tearing processes. Results in terms of crustal kinematics, patterns of lithospheric deformation and distribution and composition of magmatic phases are then compared to a natural example displaying a similar geodynamical evolution: the eastern Mediterranean subduction zone. Our modeling results suggest that the asthenospheric flow controls the ascending trajectories of mantle-derived magmatic sources developed in the mantle wedge in response to dehydration of oceanic slab. Once stored at the base of the overriding continental crust, low-viscosity mantle- and crustal-derived magmatic phases allow to decrease the lithospheric strength. This weakening then enhances the propagation of localized extensional and strike-slip deformation in response to slab roll-back and extrusion tectonics respectively. In addition, we show that storage of large amounts of low-viscosity magmas
Gualandi, A.; Perfettini, H.; Radiguet, M.; Cotte, N.; Kostoglodov, V.
2017-06-01
We present the study of 21 continuous GPS (cGPS) stations in Mexico during the time interval that goes from 1 October 2013 to 31 December 2014. The area under investigation produced a slow slip event (SSE) that started in February 2014 and lasted at least until December 2014. Superimposed on this transient signal, the Mw7.3 Papanoa earthquake struck the region on 18 April 2014 and affected multiple stations. Thanks to an independent component analysis (ICA) technique we are able to separate the postseismic deformation associated with this earthquake from the deformation related to the ongoing SSE. We infer the slip distributions associated with the three tectonically related processes: the coseismic and postseismic slip and the SSE. The inferred postseismic slip distribution reduces the amount of slip related to the SSE in the updip portion of the slab. The moment released by the postseismic processes (afterslip and aftershocks) is estimated to be [8.06 ± 0.24] × 1019 Nm, equivalent to [71 ± 4]% of the moment associated with the main shock. More than 88% of the postseismic moment is released aseismically and the afterslip spatially correlates with the Guerrero seismic gap, suggesting that the region is controlled by stable sliding behavior and rate-strengthening frictional properties.
... to follow the surgeon’s instructions for postsurgical care. Prevention To help prevent a recurrence of Haglund’s deformity: wear appropriate shoes; avoid shoes with a rigid heel back use arch supports or orthotic devices perform stretching exercises to prevent the Achilles tendon from tightening ...
Gupta, Shulabh
2015-01-01
Dispersion is at the heart of all ultrafast real-time signal processing systems across the entire electromagnetic spectrum ranging from radio-frequencies to optics. However, following Kramer-Kronig relations, these signal processing systems have been plagued with the parasitic amplitude distortions due to frequency dependent, and non-flat amplitude transmission of naturally dispersive media. This issue puts a serious limitation on the applicability and performance of these signal processing systems. To solve the above mentioned issue, a perfect dispersive medium is proposed in this work, which artificially violates the Kramer-Kronig relations, while satisfying all causality requirements. The proposed dispersive metamaterial is based on loss-gain metasurface pairs and exhibit a perfectly flat transmission response along with arbitrary dispersion in a broad bandwidth, thereby solving a seemingly unavoidable issue in all ultrafast signal processing systems. Such a metamaterial is further shown using sub-waveleng...
Fu, Xiangwen; Liu, Junfeng; Ban-Weiss, George A.; Zhang, Jiachen; Huang, Xin; Ouyang, Bin; Popoola, Olalekan; Tao, Shu
2017-09-01
Street canyons are ubiquitous in urban areas. Traffic-related air pollutants in street canyons can adversely affect human health. In this study, an urban-scale traffic pollution dispersion model is developed considering street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. In the model, vehicle exhausts generated from traffic flows first disperse inside street canyons along the micro-scale wind field generated by computational fluid dynamics (CFD) model. Then, pollutants leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing. We found that an increase in building height leads to heavier pollution inside canyons and lower pollution outside canyons at pedestrian level, resulting in higher domain-averaged concentrations over the area. In addition, canyons with highly even or highly uneven building heights on each side of the street tend to lower the urban-scale air pollution concentrations at pedestrian level. Further, increasing street widths tends to lead to lower pollutant concentrations by reducing emissions and enhancing ventilation simultaneously. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry while considering traffic demand as well as local weather patterns may significantly reduce inhalation of unhealthy air by urban residents.
Ahmed, Chaara El Mouez
Nous avons etudie les relations de dispersion et la diffusion des glueballs et des mesons dans le modele U(1)_{2+1} compact. Ce modele a ete souvent utilise comme un simple modele de la chromodynamique quantique (QCD), parce qu'il possede le confinement ainsi que les etats de glueballs. Par contre, sa structure mathematique est beaucoup plus simple que la QCD. Notre methode consiste a diagonaliser l'Hamiltonien de ce modele dans une base appropriee de graphes et sur reseau impulsion, afin de generer les relations de dispersion des glueballs et des mesons. Pour la diffusion, nous avons utilise la methode dependante du temps pour calculer la matrice S et la section efficace de diffusion des glueballs et des mesons. Les divers resultats obtenus semblent etre en accord avec les travaux anterieurs de Hakim, Alessandrini et al., Irving et al., qui eux, utilisent plutot la theorie des perturbations en couplage fort, et travaillent sur un reseau espace-temps.
Mizuki, J; Tanaka, H
2003-01-01
The employment of the X-ray anomalous dispersion effect allows us to detect the change in structure of catalytic converters with the environment exposed. Here we show that palladium atoms in a perovskite crystal move into and out of the crystal by anomalous X-ray diffraction and absorption techniques. This movement of the precious metal plays an important role to keep the catalytic activity long-lived. (author)
Mendoza, Arturo; Muñoz-Pineda, Eloy; Järrendahl, Kenneth; Arwin, Hans
2014-01-01
Variable angle Mueller matrix spectroscopic ellipsometry is used to study the properties of light reflected from the exoskeleton (cuticle) of the scarab beetle Cotinis mutabilis. For unpolarized incident light, the ellipticity and degree of polarization of the reflected light reveal a lefthanded helical structure in the beetle cuticle. Analysis of the spectral position of the maxima and minima in the interference oscillations of the Mueller-matrix elements provides evidence for a dispersion r...
Institute of Scientific and Technical Information of China (English)
Kimio; HIRABAYASHI; Goro; KIMURA; Yachiyo; FUKUNAGA; Kumiko; TSUKADA; Makoto; ANDO; Atsushi; HATTORI
2006-01-01
Adults of aquatic insects emerge fromstreamslive inthe nearby riparian zone where they can select streamsidevegetations as preferred sites in order to(a)completemetamorphosis,(b)rest while awaiting proper swarmingtime,(c)feedin order to produce eggs,or(d)mate toreproduce[1—3].Most adult aquatic insect dispersal studies have fo-cused on quantifying the degree of upstream move-ment[4,5].Some researchers have shown distinct patternsof upstreammovement related to post-mating ovipositionalbehavior[6],while there...
Romadanov, Ivan; Frias, Winston; Chapurin, Oleksandr; Koshkarov, Oleksandr
2016-01-01
MATLAB solver has been developed for studies of local instabilities in partially magnetized plasmas typical for ExB discharge plasmas. Examples for the Simon-Hoh, lower-hybrid and ion-sound instabilities in Penning discharge. The detailed behavior of the local dispersion relation can be investigated, plotted and saved with this solver. It allows to include various effects, change plasma parameters and obtain eigen-frequencies as a function of the wavenumbers in x or y directions.
Wave dispersion and propagation in state-based peridynamics
Butt, Sahir N.; Timothy, Jithender J.; Meschke, Günther
2017-07-01
Peridynamics is a nonlocal continuum model which offers benefits over classical continuum models in cases, where discontinuities, such as cracks, are present in the deformation field. However, the nonlocal characteristics of peridynamics leads to a dispersive dynamic response of the medium. In this study we focus on the dispersion properties of a state-based linear peridynamic solid model and specifically investigate the role of the peridynamic horizon. We derive the dispersion relation for one, two and three dimensional cases and investigate the effect of horizon size, mesh size (lattice spacing) and the influence function on the dispersion properties. We show how the influence function can be used to minimize wave dispersion at a fixed lattice spacing and demonstrate it qualitatively by wave propagation analysis in one- and two-dimensional models of elastic solids. As a main contribution of this paper, we propose to associate peridynamic non-locality expressed by the horizon with a characteristic length scale related to the material microstructure. To this end, the dispersion curves obtained from peridynamics are compared with experimental data for two kinds of sandstone.
Cavity coalescence in superplastic deformation
Energy Technology Data Exchange (ETDEWEB)
Stowell, M.J.; Livesey, D.W.; Ridley, N.
1984-01-01
An analysis of the probability distribution function of particles randomly dispersed in a solid has been applied to cavitation during superplastic deformation and a method of predicting cavity coalescence developed. Cavity size distribution data were obtained from two microduplex nickel-silver alloys deformed superplastically to various extents at elevated temperature, and compared to theoretical predictions. Excellent agreement occurred for small void sizes but the model underestimated the number of voids in the largest size groups. It is argued that the discrepancy results from a combination of effects due to non-random cavity distributions and to enhanced growth rates and incomplete spheroidization of the largest cavities.
Middleton, B.; Van Diggelen, R.; Jensen, K.
2006-01-01
Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and reducing genetic exchange. Species in fragmented wetlands may have lower reproductive success, which can lead to biodiversity loss. While fens may have always been relatively isolated from each other, they have become increasingly fragmented in modern times within agricultural and urban landscapes in both Europe and North America. Dispersal by water, animals and wind has been hampered by changes related to development in landscapes surrounding fens. Because the seeds of certain species are long-lived in the seed bank, frequent episodes of dispersal are not always necessary to maintain the biodiversity of fens. However, of particular concern to restoration is that some dominant species, such as the tussock sedge Carex stricta, may not disperse readily between fens. Conclusions: Knowledge of seed dispersal can be used to maintain and restore the biodiversity of fens in fragmented landscapes. Given that development has fragmented landscapes and that this situation is not likely to change, the dispersal of seeds might be enhanced by moving hay or cattle from fens to damaged sites, or by reestablishing lost hydrological connections. ?? IAVS; Opulus Press.
Giant magnon solution and dispersion relation in string theory in AdS_3 x S^3 x T^4 with mixed flux
Hoare, B; Tseytlin, A A
2013-01-01
We address the question about the exact form of the dispersion relation for light-cone string excitations in string theory in AdS3 x S3 x T4 with mixed R-R and NS-NS 3-form fluxes. The analogy with string theory in AdS5 x S5 suggests that in addition to the data provided by the perturbative near-BMN expansion and the symmetry algebra considerations there is also another source of information about the dispersion relation -- the semiclassical giant magnon solution. In earlier work in arXiv:1303.1037 and arXiv:1304.4099 it was found that the symmetry algebra constraints consistent with perturbative expansion do not completely determine the form of the dispersion relation. The aim of the present paper is to fix it by constructing a generalization of the known dyonic giant magnon soliton on S3 to the presence of a non-zero NS-NS flux described by a WZ term in the string action. We find that the angular momentum of this soliton gets shifted by a term linear in world-sheet momentum. We also discuss the symmetry alg...
Hudson, Mark R.; John, David A.; Conrad, James E.; McKee, Edwin H.
2000-01-01
Paleomagnetic and geochronologic data combined with geologic mapping tightly restrict the timing and character of a late Oligocene to early Miocene episode of large magnitude extension in the southern Stillwater Range and adjacent regions of west central Nevada. The southern Stillwater Range was the site of an Oligocene to early Miocene volcanic center comprising (1) 28.3 to 24.3 Ma intracaldera ash flow tuffs, lava flows, and subjacent plutons associated with three calderas, (2) 24.8 to 20.7 Ma postcaldera silicic dikes and domes, and (3) unconformably overlying 15.3 to 13.0 Ma dacite to basalt lava flows, plugs, and dikes. The caldera-related tuffs, lava flows, and plutons were tilted 60°-70° either west or east during the initial period of Cenozoic deformation that accommodated over 100% extension. Directions of remanent magnetization obtained from these extrusive and intrusive, caldera-related rocks are strongly deflected from an expected Miocene direction in senses appropriate for their tilt. A mean direction for these rocks after tilt correction, however, suggests that they were also affected by a moderate (33.4° ± 11.8°) component of counterclockwise vertical axis rotation. Paleomagnetic data indicate that the episode of large tilting occurred during emplacement of 24.8 to 20.7 Ma postcaldera dikes and domes. In detail, an apparent decrease in rotation with decreasing age of individual, isotopically dated bodies of the postcaldera group indicates that most tilting occurred between 24.4 and 24.2 Ma. The onset of tilting immediately following after the final caldera eruptions suggests that the magmatism and deformation were linked. Deformation was not driven by magma buoyancy, however, because tilting equally affected the caldera systems of different ages, including their plutonic roots. It is more likely that regional extension was focused in the southern Stillwater Range due to magmatic warming and reduction of tensile strength of the brittle crust
Directory of Open Access Journals (Sweden)
G. M. S. ALVA
Full Text Available Brazilian Codes NBR 6118 and NBR 15575 provide practical values for interstory drift limits applied to conventional modeling in order to prevent negative effects in masonry infill walls caused by excessive lateral deformability, however these codes do not account for infill walls in the structural model. The inclusion of infill walls in the proposed model allows for a quantitative evaluation of structural stresses in these walls and an assessment of cracking in these elements (sliding shear diagonal tension and diagonal compression cracking. This paper presents the results of simulations of single-story one-bay infilled R/C frames. The main objective is to show how to check the serviceability limit states under lateral loads when the infill walls are included in the modeling. The results of numerical simulations allowed for an evaluation of stresses and the probable cracking pattern in infill walls. The results also allowed an identification of some advantages and limitations of the NBR 6118 practical procedure based on interstory drift limits.
Directory of Open Access Journals (Sweden)
van Doorn-Loogman Mirjam H
2009-05-01
Full Text Available Abstract Background A substantial number of children with an obstetric brachial plexus lesion (OBPL will develop internal rotation adduction contractures of the shoulder, posterior humeral head subluxations and glenohumeral deformities. Their active shoulder function is generally limited and a recent study showed that their shoulder muscles were atrophic. This study focuses on the role of shoulder muscles in glenohumeral deformation and function. Methods This is a prospective study on 24 children with unilateral OBPL, who had internal rotation contractures of the shoulder (mean age 3.3 years, range 14.7 months to 7.3 years. Using MR imaging from both shoulders the following parameters were assessed: glenoid form, glenoscapular angle, subluxation of the humeral head, thickness and segmental volume of the subscapularis, infraspinatus and deltoid muscles. Shoulder function was assessed measuring passive external rotation of the shoulder and using the Mallet score for active function. Statistical tests used are t-tests, Spearman's rho, Pearsons r and logistic regression. Results The affected shoulders showed significantly reduced muscle sizes, increased glenoid retroversion and posterior subluxation. Mean muscle size compared to the normal side was: subscapularis 51%, infraspinatus 61% and deltoid 76%. Glenoid form was related to infraspinatus muscle atrophy. Subluxation was related to both infraspinatus and subscapularis atrophy. There was no relation between atrophy of muscles and passive external rotation. Muscle atrophy was not related to the Mallet score or its dimensions. Conclusion Muscle atrophy was more severe in the subscapularis muscle than in infraspinatus and deltoid. As the muscle ratios are not related to passive external rotation nor to active function of the shoulder, there must be other muscle properties influencing shoulder function.
Institute of Scientific and Technical Information of China (English)
M. CHATTERJEE; A. CHATTOPADHYAY
2015-01-01
The propagation, reflection, and transmission of SH waves in slightly com-pressible, finitely deformed elastic media are considered in this paper. The dispersion relation for SH-wave propagation in slightly compressible, finitely deformed layer over-lying a slightly compressible, finitely deformed half-space is derived. The present paper also deals with the reflection and refraction (transmission) phenomena due to the SH wave incident at the plane interface between two distinct slightly compressible, finitely deformed elastic media. The closed form expressions for the amplitude ratios of reflection and refraction coeﬃcients of the reflected and refracted SH waves are obtained from suit-able boundary conditions. For the numerical discussions, we consider the Neo-Hookean form of a strain energy function. The phase speed curves, the variations of reflection, and transmission coeﬃcients with the angle of incidence, and the plots of the slowness sections are presented by means of graphs.
Shen, Yue; Ho, Luis C; Brandt, W N; Denney, Kelly D; Horne, Keith; Jiang, Linhua; Kochanek, Christopher S; McGreer, Ian D; Merloni, Andrea; Peterson, Bradley M; Petitjean, Patrick; Schneider, Donald P; Schulze, Andreas; Strauss, Michael A; Tao, Charling; Trump, Jonathan R; Pan, Kaike; Bizyaev, Dmitry
2015-01-01
We present host stellar velocity dispersion measurements for a sample of 88 broad-line quasars at 0.10.6) from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. High signal-to-noise ratio coadded spectra (average S/N~30 per 69 km/s pixel) from SDSS-RM allowed decomposition of the host and quasar spectra, and measurement of the host stellar velocity dispersions and black hole (BH) masses using the single-epoch (SE) virial method. The large sample size and dynamic range in luminosity (L5100=10^(43.2-44.7) erg/s) lead to the first clear detection of a correlation between SE virial BH mass and host stellar velocity dispersion far beyond the local universe. However, the observed correlation is significantly flatter than the local relation, suggesting that there are selection biases in high-z luminosity-threshold quasar samples for such studies. Our uniform sample and analysis enable an investigation of the redshift evolution of the M-sigma relation free of caveats by comparing different samples...
Giant magnon on deformed AdS3×S3
Khouchen, Malak; KlusoÅ, Josef
2014-09-01
We study giant magnon solutions for strings moving on a deformed AdS3×S3 background. We impose a conformal gauge on the Polyakov action and proceed with solving the Virasoro constraints. The expressions of the conserved charge J and the energy of a single magnon excitation are then computed. Then we determine the dispersion relation of a giant magnon in the infinite J limit configuration and we find that for κ =0 it reduces to the celebrated Hofman-Maldacena dispersion relation.
Bezák, V
2003-02-01
The Waxman-Peck theory of population genetics is discussed in regard of soil bacteria. Each bacterium is understood as a carrier of a phenotypic parameter p. The central objective is the calculation of the probability density with respect to p, Phi(p,t;p(0)), of the carriers living at time t>0, provided that initially at t(0)=0, all bacteria carried the phenotypic parameter p(0)=0. The theory involves two small parameters: the mutation probability mu and a parameter gamma involved in a function w(p) defining the fitness of the bacteria to survive the generation time tau and give birth to an offspring. The mutation from a state p to a state q is defined by a Gaussian with a dispersion sigma(2)(m). The author focuses our attention on a function phi(p,t) which determines uniquely the function Phi(p,t;p(0)) and satisfies a linear equation (Waxman's equation). The Green function of this equation is mathematically identical with the one-particle Bloch density matrix, where mu characterizes the order of magnitude of the potential energy. (In the x representation, the potential energy is proportional to the inverted Gaussian with the dispersion sigma(2)(m)). The author solves Waxman's equation in the standard style of a perturbation theory and discusses how the solution depends on the choice of the fitness function w(p). In a sense, the function c(p)=1-w(p)/w(0) is analogous to the dispersion function E(p) of fictitious quasiparticles. In contrast to Waxman's approximation, where c(p) was taken as a quadratic function, c(p) approximately gammap(2), the author exemplifies the problem with another function, c(p)=gamma[1-exp(-ap(2))], where gamma is small but a may be large. The author shows that the use of this function in the theory of the population genetics is the same as the use of a nonparabolic dispersion law E=E(p) in the density-matrix theory. With a general function c(p), the distribution function Phi(p,t;0) is composed of a delta-function component, N
Mobley, Joel; Mack, Richard A; Gladden, Joseph R; Mantena, P Raju
2009-07-01
Using a broadband through-transmission technique, the attenuation coefficient and phase velocity spectra have been measured for a set of multi-wall carbon nanotube (MWCNT)-nylon composites (from pure nylon to 20% MWCNT by weight) in the ultrasonic frequency band from 4 to 14 MHz. The samples were found to be effectively homogeneous on spatial scales from the low end of ultrasonic wavelengths investigated and up (>0.2 mm). Using Kramers-Kronig relations, the attenuation and dispersion data were found to be consistent with a power-law attenuation model with a range of exponents from y=1.12 to y=1.19 over the measurement bandwidth. The attenuation coefficients of the respective samples are found to decrease with increasing MWCNT content and a similar trend holds also for the dispersion. In contrast, the mean phase velocities for the samples rise with increasing MWCNT content indicating an increase in the mechanical moduli.
Energy Technology Data Exchange (ETDEWEB)
Bavaro, A. (Soliveri SpA, Caravaggio (Italy))
1990-02-01
Types and causes of heat treatement derived isotropic and anisotropic dilatancies in ferrous materials are reviewed. The concepts are developed in such a way as to allow extension to all materials exhibiting martensitic tempering behaviour. This paper intends to illustrate the basic processes of dimensional variations undergone by the materials under heat treatments. The parametric analysis includes an analysis of the interactions amongst the parameters themselves. The relative importance of each parameter is assessed in order to determine methods to attenuate deformation action. Simplified examples are offered to provide technicians explanations as to why specific deformations occur and indications on improved materials working techniques.
Metastable vacua and geometric deformations
Amariti, A; Girardello, L; Mariotti, A
2008-01-01
We study the geometric interpretation of metastable vacua for systems of D3 branes at non isolated toric deformable singularities. Using the L^{aba} examples, we investigate the relations between the field theoretic susy breaking and restoration and the complex deformations of the CY singularities.
Directory of Open Access Journals (Sweden)
Yao-Qi Zhou
2017-04-01
The SSDS types in the Qingshan Group includes load and flame structure, ball and pillow structure, water-escape structure, hydroplastic deformation structure, plastic sandstone breccia structure, volcanic drop stone and V-shaped ground fissure mainly caused by volcanic earthquakes of three types: (1 seismic waves, (2 gravity and inertia effect of pyroclastic flows, (3 instant differential air pressure; which is different from slumping and tectonic earthquakes occurred in the Laiyang Group. In addition, with the lithofacies association analysis between pyroclastic flow and SSDS beds, a distribution model of SSDS related to volcanic earthquakes can be established: SSDS types changed gradually with their distance further away from the volcanic activity core. Brittle deformation which was common in the proximal zone disappeared gradually; liquefied and plastic SSDS continued to dominate in the medial zone; and slightly liquefied SSDS were developed in the distal zone. Meanwhile, the scale and size of SSDS is negatively correlated with the distance of SSDS depositional locations from the volcanic vent.
Kanada-Enyo, Y
2004-01-01
Systematic analysis of the deformations of proton and neutron densities in even-even C isotopes was done based on the method of antisymmetrized molecular dynamics. The $E2$ transition strength was discussed in relation to the deformation. We analyze the $B(E2;2^+_1\\to 0^+_1)$ in $^{16}$C, which has been recently measured to be abnormally small. The results suggest the difference of the deformations between proton and neutron densities in the neutron-rich C isotopes. It was found that stable proton structure in C isotopes plays an important role in the enhancement the neutron skin structure as well as in the systematics of $B(E2)$ in the neutron-rich C.
Black hole remnants due to Planck-length deformed QFT
Dirkes, Alain R. P.; Maziashvili, Michael; Silagadze, Zurab K.
2016-10-01
It was argued in a number of papers that the gravitational potential calculated by using the modified QFT that follows from the Planck-length deformed uncertainty relation implies the existence of black hole (BH) remnants of the order of the Planck mass. Usually, this sort of QFTs are endowed with two specific features, the modified dispersion relation, which is universal, and the concept of minimum length, which, however, is not universal. While the emergence of the minimum length most readily leads to the idea of the BH remnants, here, we examine the behavior of the potential that follows from the Planck-length deformed QFT in the absence of the minimum length and show that it might also lead to the formation of the Planck mass BHs in some particular cases. The calculations are made for higher-dimensional case as well. Such BH remnants might be considered as a possible candidates for the dark-matter.
Constructal Hypothesis for Mechanical Deformation
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Atanu Chatterjee
2012-08-01
Full Text Available Mild Steel specimen, when subjected to tensile forces shows considerable plastic deformation before fracture. A cross-section of the fractured specimen has the familiar cup – cone form and shows traces of a three – dimensional parabolic geometry. The morphing of the steel specimen from a volume to a point as a spontaneous, entropy producing or energy dispersing process is analysed using the Constructal law.
Dispersive hydrodynamics: Preface
Biondini, G.; El, G. A.; Hoefer, M. A.; Miller, P. D.
2016-10-01
This Special Issue on Dispersive Hydrodynamics is dedicated to the memory and work of G.B. Whitham who was one of the pioneers in this field of physical applied mathematics. Some of the papers appearing here are related to work reported on at the workshop "Dispersive Hydrodynamics: The Mathematics of Dispersive Shock Waves and Applications" held in May 2015 at the Banff International Research Station. This Preface provides a broad overview of the field and summaries of the various contributions to the Special Issue, placing them in a unified context.
Ozawa, Hajime; Watanabe, Atsushi; Uchiyama, Kentaro; Saito, Yoko; Ide, Yuji
2013-01-01
Long-distance dispersal (LDD) of seeds has a critical impact on species survival in patchy landscapes. However, relative to pollen dispersal, empirical data on how seed LDD affects genetic diversity in fragmented populations have been poorly reported. Thus, we attempted to indirectly evaluate the influence of seed LDD by estimating maternal and paternal inbreeding in the seed rain of fragmented 8 Pinus densiflora populations. In total, the sample size was 458 seeds and 306 adult trees. Inbreeding was estimated by common parentage analysis to evaluate gene flow within populations and by sibship reconstruction analysis to estimate gene flow within and among populations. In the parentage analysis, the observed probability that sampled seeds had the same parents within populations was significantly larger than the expected probability in many populations. This result suggested that gene dispersal was limited to within populations. In the sibship reconstruction, many donors both within and among populations appeared to contribute to sampled seeds. Significant differences in sibling ratios were not detected between paternity and maternity. These results suggested that seed-mediated gene flow and pollen-mediated gene flow from outside population contributed some extent to high genetic diversity of the seed rain (H E > 0.854). We emphasize that pine seeds may have excellent potential for gene exchange within and among populations.
Institute of Scientific and Technical Information of China (English)
ZHONG Yu; SHEN Lin-Fang; RAN Li-Xin; CHEN Xu-Dong; Liisi Jylh(a); Tomasz M. Grzegorczyk; Jin Au Kong
2006-01-01
@@ Wave reflection and refraction at the interface between a normal media and a one-dimensional left-handed material (1 DLHM) with a hyperbolic dispersion relationship is studied. It is found that in a special case that the boundary is perpendicular to one asymptotic line of the hyperbola, phase matching cannot be achieved unless the 1 DLHM is regarded to be intrinsically lossy. After introducing a small loss factor to the 1 DLHM, a reasonable solution for the phase matching is obtained. According to the analytical result, a wave confined to a thin layer near the boundary is found, which can be excited at the interface as a reflected wave or a refracted wave attenuating drastically away from the boundary inside the 1 DLHM in both cases.
Smith, Kevin T.; Balouet, Jean Christophe; Shortle, Walter C.; Chalot, Michel; Beaujard, François; Grudd, Håkan; Vroblesky, Don A.; Burkem, Joel G.
2014-01-01
Energy dispersive X-ray fluorescence (EDXRF) provides highly sensitive and precise spatial resolution of cation content in individual annual growth rings in trees. The sensitivity and precision have prompted successful applications to forensic dendrochemistry and the timing of environmental releases of contaminants. These applications have highlighted the need to distinguish dendrochemical effects of internal processes from environmental contamination. Calcium, potassium, and zinc are three marker cations that illustrate the influence of these processes. We found changes in cation chemistry in tree rings potentially due to biomineralization, development of cracks or checks, heartwood/sapwood differentiation, intra-annual processes, and compartmentalization of infection. Distinguishing internal from external processes that affect dendrochemistry will enhance the value of EDXRF for both physiological and forensic investigations.
Haschenburger, J. K.
2010-12-01
Sediment transfers in gravel-bed rivers involve the three-dimensional dispersion of mixed size sediment. From a kinematics standpoint, few studies are available to inform on the streamwise and vertical rates of sediment dispersion in natural channels. This research uses a gravel tracing program to quantify dispersion rates over 19 flood seasons. Empirical observations come from Carnation Creek, a small gravel-bed river with large woody debris located on the west coast of Vancouver Island, Canada. Frequent floods and the relatively limited armor layer facilitate streambed activity and relatively high bedload transport rates, typically under partial sediment transport conditions. Over 2500 magnetically tagged stones, ranging in size from 16 to 180 mm, were deployed on the bed surface between 1989 and 1992 in four generations. To quantify gravel dispersion over distances up to 2.6 km, observations are taken from 11 recoveries. Over 280 floods capable of moving bedload occurred during this period, with five exceeding the estimated bankfull discharge. Streamwise dispersion is quantified by virtual velocity, while dispersion into the streambed is quantified by a vertical burial rate. The temporal trend in streamwise dispersion rates is described by a power function. Initial virtual velocities decline rapidly from around 1.4 m/hr to approach an asymptote value of about 0.2 m/hr. The rapid change corresponds to a significant increase in the proportion of buried tracers due to vertical mixing. Initial burial rates reflect the magnitude of the first flood after tracer deployment and range from 0.07 to 0.46 cm/hr depending on tracer generation. Burial rates converge to about 0.06 cm/hr after the fourth flood season and then gradually decline to about 0.01 cm/hr. Thus, the rate of streamwise dispersion exceeds that of vertical dispersion by three orders of magnitude when the movement of sediment routinely activated by floods is considered.
Dispersion relation for ion-acoustic waves in plasma%等离子体中离子声波的色散关系
Institute of Scientific and Technical Information of China (English)
张开彪; 王红艳
2013-01-01
以含有满足玻耳兹曼分布的低温电子、远离平衡态的高温电子和离子组成的等离子体为研究对象,推导得到在该等离子体中传播的离子声波的色散关系.利用数值模拟方法讨论系统参数如快电子数、两种电子温度之比和数密度比值对离子声波的色散关系的影响.结果表明:系统参数的变化均会影响和改变着系统的色散关系,其中ω2随快电子数α的增大而增大.%A plasma which consisted of lower temperature Boltzmann distributed electrons,higher temperature non-thermal distributed electrons and ions was studied and the dispersion relation of ionacoustic waves was obtained in this paper.The effects and influences of system parameters,such as the fast electrons number,the ratio of the two electrons temperatures,and the ratio of the two electrons densities on the dispersion relation of the ion-acoustic waves were analyzed carefully by using numerical simulation method.The results showed that variation of the plasma parameters has an important influence on the dispersion relation of this system.In addition,ω2 increase with the increase of the fast electrons number α.
Pulse compression by use of deformable mirrors.
Zeek, E; Maginnis, K; Backus, S; Russek, U; Murnane, M; Mourou, G; Kapteyn, H; Vdovin, G
1999-04-01
An electrostatically deformable, gold-coated, silicon nitride membrane mirror was used as a phase modulator to compress pulses from 92 to 15 fs. Both an iterative genetic algorithm and single-step dispersion compensation based on frequency-resolved optical gating calibration of the mirror were used to compress pulses to within 10% of the transform limit. Frequency-resolved optical gating was used to characterize the pulses and to test the range of the deformable-mirror-based compressor.
Laveissière, G; Degrande, N; Jaminion, S; Jutier, C; Di Salvo, R; Van Hoorebeke, L; Alexa, L C; Anderson, B D; Aniol, K A; Arundell, K; Audit, G; Auerbach, L; Baker, F T; Baylac, M; Berthot, J; Bertin, P Y; Bertozzi, W; Bimbot, L; Böglin, W; Brash, E J; Breton, V; Breuer, H; Burtin, E; Calarco, J R; Cardman, L S; Cavata, C; Chang, C C; Chen, J P; Chudakov, E; Cisbani, E; Dale, D S; De Jager, C W; De Leo, R; Deur, A; D'Hose, N; Dodge, G E; Domingo, John J; Elouadrhiri, L; Epstein, M B; Ewell, L A; Finn, J M; Fissum, K G; Fonvieille, H; Fournier, G; Frois, B; Frullani, S; Furget, C; Gao, H; Gao, J; Garibaldi, F; Gasparian, A; Gilad, S; Gilman, R; Glamazdin, A; Glashausser, C; Gómez, J; Gorbenko, V; Grenier, P; Guichon, P A M; Hansen, J O; Holmes, R; Holtrop, M; Howell, C; Huber, G M; Hyde-Wright, C E; Incerti, S; Iodice, M; Jardillier, J; Jones, M K; Kahl, W; Kato, S; Katramatou, A T; Kelly, J J; Kerhoas, S; Ketikyan, A; Khayat, M; Kino, K; Kox, S; Kramer, L H; Kumar, K S; Kumbartzki, G; Kuss, M; Leone, A; Le Rose, J J; Liang, M; Lindgren, R A; Liyanage, N; Lolos, G J; Lourie, R W; Madey, R; Maeda, K; Malov, S; Manley, D M; Marchand, C; Marchand, D; Margaziotis, D J; Markowitz, P; Marroncle, J; Martino, J; Martoff, C J; McCormick, K; McIntyre, J; Mehrabyan, S S; Merchez, F; Meziani, Z E; Michaels, R; Miller, G W; Mougey, J Y; Nanda, S K; Neyret, D; Offermann, E A J M; Papandreou, Z; Pasquini, B; Perdrisat, C F; Perrino, R; Petratos, G G; Platchkov, S; Pomatsalyuk, R I; Prout, D L; Punjabi, V A; Pussieux, T; Quéméner, G; Ransome, R D; Ravel, O; Real, J S; Renard, F; Roblin, Y; Rowntree, D; Rutledge, G; Rutt, P M; Saha, A; Saitô, T; Sarty, A J; Serdarevic, A; Smith, T; Smirnov, G; Soldi, K; Sorokin, P; Souder, P A; Suleiman, R; Templon, J A; Terasawa, T; Tieulent, R; Tomasi-Gustafsson, E; Tsubota, H; Ueno, H; Ulmer, P E; Urciuoli, G M; Vanderhaeghen, M; Van De Vyver, R; Van der Meer, R L J; Vernin, P; Vlahovic, B; Voskanyan, H; Voutier, E; Watson, J W; Weinstein, L B; Wijesooriya, K; Wilson, R; Wojtsekhowski, B B; Zainea, D G; Zhang, W M; Zhao, J; Zhou, Z L
2003-01-01
Virtual Compton Scattering is studied at the Thomas Jefferson National Accelerator Facility in the energy domain below pion threshold and in the Delta(1232) resonance region. The data analysis is based on the Dispersion Relation (DR) approach. The electric and magnetic Generalized Polarizabilities (GPs) of the proton and the structure functions Pll-Ptt/epsilon and Plt are determined at four-momentum transfer squared Q2=0.92 and 1.76 GeV2. The DR analysis is consistent with the low-energy expansion analysis. The world data set indicates that neither the electric nor magnetic GP follows a simple dipole form.
Institute of Scientific and Technical Information of China (English)
Wei Wang; Lantian Hou; Zhaolun Liu; Guiyao Zhou
2009-01-01
When using normalized dispersion method for the dispersion design of photonic crystal fibers(PCFs),it is vital that the group velocity dispersion of PCF can be seen as the sum of geometrical dispersion and material dispersion.However,the error induced by this way of calculation will deteriorate the final results.Taking 5 ps/(km·nm)and 5% as absolute error and relative error limits,respectively,the structure parameter boundaries of PCFs about when separating total dispersion into geometrical and material components is valid are provided for wavelength shorter than 1700 nm.By using these two criteria together,it is adequate to evaluate the simulatcd dispersion of PCFs when normalized dispersion method is employed.
Gervais, Olivier; Nirasawa, Keijiro; Vincenot, Christian E; Nagamine, Yoshitaka; Moriya, Kazuyuki
2017-02-01
Although non-destructive deformation is relevant for assessing eggshell strength, few long-term selection experiments are documented which use non-destructive deformation as a selection criterion. This study used restricted maximum likelihood-based methods with a four-trait animal model to analyze the effect of non-destructive deformation on egg production, egg weight and sexual maturity in a two-way selection experiment involving 17 generations of White Leghorns. In the strong shell line, corresponding to the line selected for low non-destructive deformation values, the heritability estimates were 0.496 for non-destructive deformation, 0.253 for egg production, 0.660 for egg weight and 0.446 for sexual maturity. In the weak shell line, corresponding to the line selected for high non-destructive deformation values, the heritabilities were 0.372, 0.162, 0.703 and 0.404, respectively. An asymmetric response to selection was observed for non-destructive deformation, egg production and sexual maturity, whereas egg weight decreased for both lines. Using non-destructive deformation to select for stronger eggshell had a small negative effect on egg production and sexual maturity, suggesting the need for breeding programs to balance selection between eggshell traits and egg production traits. However, the analysis of the genetic correlation between non-destructive deformation and egg weight revealed that large eggs are not associated with poor eggshell quality.
Zong, Baoyu
2014-01-01
Organic hybrid solar cells with a large open-circuit voltage, up to above that of 1.5 V standard battery voltage, were demonstrated using blends of polypyrrole: Fe2O3·ZnO nanoparticles as active-layers. The cell active-layers were readily coated in open air from relatively stable liquid dark-color polypyrrole-based dispersions, which were synthesized using appropriate surfactants during the in situ polymerization of pyrrole with FeCl3 or both H2O2 and FeCl3 as the oxidizers. The performance of the cells depends largely on the synthesized blend phase, which is determined by the surfactants, oxidizers, as well as the reactant ratio. Only the solar cells fabricated from the stable dispersions can produce both a high open-circuit voltage (>1.0 V) and short-circuit current (up to 7.5 mA cm-2) due to the relatively uniform porous network nanomorphology and higher shunt to series resistance ratio of the active-layers. The cells also display a relatively high power-conversion efficiency of up to ∼3.8%. This journal is
Bezak, V
2002-01-01
The Waxman-Peck theory of the population genetics is discussed in regard of soil bacteria. Each bacterium is understood as a carrier of a phenotypic parameter p. The central aim is the calculation of the probability density with respect to p of the carriers living at time t>0. The theory involves two small parameters: the mutation probability $\\mu$ and a parameter $\\gamma$ involved in a function w(p) defining the fitness of the bacteria to survive the generation time $\\tau$ and give birth to offspring. The mutation from a state p to a state q is defined by a Gaussian. The author focuses attention on an equation generalizing Waxman's equation. The author solves this equation in the standard style of a perturbation theory and discusses how the solution depends on the choice of the fitness function w(p). In a sense, the function $c(p)=1-w(p)/w(0)$ is analogous to the dispersion function E(p) of fictitious quasiparticles. With a general function c(p), the distribution function ${\\mathit\\Phi}(p,t;0)$ is composed o...
Lattice dynamics of xenotime: The phonon dispersion relations and density of states of LuPO{sub 4}
Energy Technology Data Exchange (ETDEWEB)
Nipko, J.C.; Loong, C. [Argonne National Laboratory, Argonne, Illinois 60439-4814 (United States); Loewenhaupt, M. [Technische Universitaet Dresden, Dresden (Germany); Braden, M.; Reichardt, W. [Forschungszentrum Karlsruhe, INFP, D-76021, Karlsruhe (Germany); Boatner, L.A. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6056 (United States)
1997-11-01
LuPO{sub 4} is the nonmagnetic end member of a series of rare-earth phosphates with a common zircon-type crystal structure. The phonon-dispersion curves of LuPO{sub 4} along the [x,0,0], [x,x,0], and [0,0,x] symmetry directions were measured by neutron triple-axis spectroscopy using single-crystal samples. The phonon density of states was determined by time-of-flight neutron scattering using polycrystalline samples. Phonons involving mainly motions of rare-earth ions were found to be well separated in energy from those of the P and O vibrations. A large gap in the phonon-frequency-distribution function, which divides the O-P-O bending-type motions from the P-O stretches, was observed. All of the experimental results were satisfactorily accounted for by lattice-dynamic shell-model calculations. LuPO{sub 4} is a host material for the incorporation of rare-earth ions to produce activated luminescence. Information regarding the phonon and thermodynamic properties of LuPO{sub 4} is pertinent to extended investigations of additional rare-earth spin-lattice interactions in other zircon-structure rare-earth orthophosphates. {copyright} {ital 1997} {ital The American Physical Society}
Directory of Open Access Journals (Sweden)
Marjo Saastamoinen
Full Text Available Organisms in the wild are constantly faced with a wide range of environmental variability, such as fluctuation in food availability. Poor nutritional conditions influence life-histories via individual resource allocation patterns, and trade-offs between competing traits. In this study, we assessed the influence of food restriction during development on the energetically expensive traits flight metabolic rate (proxy of dispersal ability, encapsulation rate (proxy of immune defence, and lifespan using the Glanville fritillary butterfly, Melitaea cinxia, as a model organism. Additionally, we examined the direct costs of flight on individual immune function, and whether those costs increase under restricted environmental conditions. We found that nutritional restriction during development enhanced adult encapsulations rate, but reduced both resting and flight metabolic rates. However, at the individual level metabolic rates were not associated with encapsulation rate. Interestingly, individuals that were forced to fly prior to the immune assays had higher encapsulation rates than individuals that had not flown, suggesting that flying itself enhances immune response. Finally, in the control group encapsulation rate correlated positively with lifespan, whereas in the nutritional restriction group there was no relationship between these traits, suggesting that the association between encapsulation rate on adult lifespan was condition-dependent. Thus stressful events during both larval development (food limitation and adulthood (forced flight induce increased immune response in the adult butterflies, which may allow individuals to cope with stressful events later on in life.
Budiansky, Stephen
1980-01-01
This article discusses the need for more accurate and complete input data and field verification of the various models of air pollutant dispension. Consideration should be given to changing the form of air quality standards based on enhanced dispersion modeling techniques. (Author/RE)
Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.
2016-01-01
Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil biodeg
Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.
2016-01-01
Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil
Lentz, Martin; Klaus, Manuela; Coelho, Rodrigo S.; Schaefer, Nobert; Schmack, Florian; Reimers, Walter; Clausen, Bjørn
2014-11-01
The deformation behavior of the Mg-RE alloys ME21 and WE54 was investigated. Although both alloys contain rare earth elements, which alter and weaken the texture, the flow curves of the alloys deviate significantly, especially in uniaxial compression test. Apart from the higher strength of the WE54 alloy, the compression flow curve does not exhibit the typical sigmoidal shape, which is associated with tension twinning. However, optical microscopy, X-ray texture measurements, and EBSD analysis reveal the activity of tension twinning. The combination of in situ energy-dispersive X-ray synchrotron diffraction and EPSC modeling was used to analyze these differences. The investigation reveals that twin propagation is decelerated in the WE54 alloy, which requires a change of the twinning scheme from the `finite initial fraction' to the `continuity' assumption. Furthermore, an enhanced activity of the pyramidal slip system was observed in case of the WE54 alloy.
Loop-deformed Poincar\\'e algebra
Mielczarek, Jakub
2013-01-01
In this essay we present evidence suggesting that loop quantum gravity leads to deformation of the local Poincar\\'e algebra within the limit of high energies. This deformation is a consequence of quantum modification of effective off-shell hypersurface deformation algebra. Surprisingly, the form of deformation suggests that the signature of space-time changes from Lorentzian to Euclidean at large curvatures. We construct particular realization of the loop-deformed Poincar\\'e algebra and find that it can be related to curved momentum space, which indicates the relationship with recently introduced notion of relative locality. The presented findings open a new way of testing loop quantum gravity effects.
Institute of Scientific and Technical Information of China (English)
Lei XU; Rhett D. HARRISON; Pei YANG; Da-Rong YANG
2011-01-01
Studies on the evolution of tropical taxa emphasize the role ofvicariance and the break-up of Gondwana in explaining modern distributions.Earlier studies on figs (Ficus spp.) support this view.In the current study,we used an expanded sample (208 spp.) and improved molecular dating techniques to reconstruct the phylogenetic and biogeographic history of Ficus.Consistent with previous studies,our biogeographic analysis indicated that the ancestor of Ficus was present in Gondwana.However,a relaxed clock analysis relying on uncorrelated rates in BEAST suggested that the Neotropical section Pharmacosycea split-off in South America 86.67 Mya,and that other Ficus lineage ancestors originated in India.Most of the basal lineages appeared to have diverged following KT extinction,then rapidly diversified after India collided with continental Asia.The Afrotropical species most likely evolved initially in the Indian subcontinent then dispersed to Africa,either in the late Cretaceous of Madagascar or even later,following the Eocene collision of India with Asia.The Neotropical section Americana,either islandhopped to South America or took a northern route to the Americas through Europe prior to the terminal Eocene global cooling event.Ficus may have arrived in eastern Malesia following the collision of India with Asia,then widely dispersed thereafter.Given the wide ranges in our date estimates,several other scenarios are possible.However,contrary to earlier reports,our analyses suggest that vicariance played a relatively minor role compared with ecological opportunity and dispersal in the diversification of genus Ficus.
Boedeltje, G.; Bakker, J.P.; Brinke, A. Ten; Groenendael, J.M. van; Soesbergen, M.
2004-01-01
1 Restored floodplains and backwaters lacking a viable propagule bank, may need flood pulses to facilitate inward dispersal of diaspores. Temporal patterns of hydrochorous plant dispersal are, however, not well known. 2 Diversity and abundance of diaspores dispersed in a water body over 12 months
Boedeltje, G; Bakker, JP; Ten Brinke, A; Van Groenendael, JM; Soesbergen, M
2004-01-01
1 Restored floodplains and backwaters lacking a viable propagule bank, may need flood pulses to facilitate inward dispersal of diaspores. Temporal patterns of hydrochorous plant dispersal are, however, not well known. 2 Diversity and abundance of diaspores dispersed in a water body over 12 months
Fickian dispersion is anomalous
Cushman, John H.; O'Malley, Dan
2015-12-01
The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion we illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.
Vehicular traffic is a major source of ambient air pollution in urban areas, and traffic-related air pollutants, including carbon monoxide, nitrogen oxides, particulate matter under 2.5 microns in diameter (PM2.5) and diesel exhaust emissions, have been associated with...
Vehicular traffic is a major source of ambient air pollution in urban areas, and traffic-related air pollutants, including carbon monoxide, nitrogen oxides, particulate matter under 2.5 microns in diameter (PM2.5) and diesel exhaust emissions, have been associated with...
Large deformation behavior of fat crystal networks
Kloek, W.; Vliet, van T.; Walstra, P.
2005-01-01
Compression and wire-cutting experiments on dispersions of fully hydrogenated palm oil in sunflower oil with varying fraction solid fat were carried out to establish which parameters are important for the large deformation behavior of fat crystal networks. Compression experiments showed that the app
Emmons, S; Phan, H; Calley, J; Chen, W; James, B; Manseau, L
1995-10-15
We report the molecular isolation of cappuccino (capu), a gene required for localization of molecular determinants within the developing Drosophila oocyte. The carboxy-terminal half of the capu protein is closely related to that of the vertebrate limb deformity locus, which is known to function in polarity determination in the developing vertebrate limb. In addition, capu shares both a proline-rich region and a 70-amino-acid domain with a number of other genes, two of which also function in pattern formation, the Saccharomyes cerevisiae BNI1 gene and the Aspergillus FigA gene. We also show that capu mutant oocytes have abnormal microtubule distributions and premature microtubule-based cytoplasmic streaming within the oocyte, but that neither the speed nor the timing of the cytoplasmic streaming correlates with the strength of the mutant allele. This suggests that the premature cytoplasmic streaming in capu mutant oocytes does not suffice to explain the patterning defects. By inducing cytoplasmic streaming in wild-type oocytes during mid-oogenesis, we show that premature cytoplasmic streaming can displace staufen protein from the posterior pole, but not gurken mRNA from around the oocyte nucleus.
Energy Technology Data Exchange (ETDEWEB)
Scherneck, H.G.; Johansson, J.M.; Elgered, G. [Chalmers Univ. of Technology, Goeteborg (Sweden). Onsala Space Observatory
1996-04-01
This report introduces into space geodetic measurements of relative positions over distances ranging from tens to thousands of kilometers. Such measurements can routinely be carried out with repeatabilities on the order of a few millimeters. The techniques presented are Very Long Baseline Interferometry (VLBI), employing observations of radio-astronomical objects in the distant universe, and ranging measurements to satellites of the GPS, the Global Positioning System. These techniques have helped to trace plate tectonic motions. More recently, deformations within continents have been detected. We present the SWEPOS system of permanently operating GPS stations as one of the major geoscience investments starting in 1993. BIFROST (Baseline Interference for Fennoscandian Rebound Observations, Sea level, and Tectonics) is a project within SWEPOS with main purpose to detect crustal movements in Fennoscandia. First results are presented, indicating movements which generally support the notion of a dominating displacement pattern due to the postglacial rebound of Fennoscandia. However deviations exist. densification is indicated in those areas which are notable for an increased seismicity. 148 refs.
Perceptual transparency from image deformation.
Kawabe, Takahiro; Maruya, Kazushi; Nishida, Shin'ya
2015-08-18
Human vision has a remarkable ability to perceive two layers at the same retinal locations, a transparent layer in front of a background surface. Critical image cues to perceptual transparency, studied extensively in the past, are changes in luminance or color that could be caused by light absorptions and reflections by the front layer, but such image changes may not be clearly visible when the front layer consists of a pure transparent material such as water. Our daily experiences with transparent materials of this kind suggest that an alternative potential cue of visual transparency is image deformations of a background pattern caused by light refraction. Although previous studies have indicated that these image deformations, at least static ones, play little role in perceptual transparency, here we show that dynamic image deformations of the background pattern, which could be produced by light refraction on a moving liquid's surface, can produce a vivid impression of a transparent liquid layer without the aid of any other visual cues as to the presence of a transparent layer. Furthermore, a transparent liquid layer perceptually emerges even from a randomly generated dynamic image deformation as long as it is similar to real liquid deformations in its spatiotemporal frequency profile. Our findings indicate that the brain can perceptually infer the presence of "invisible" transparent liquids by analyzing the spatiotemporal structure of dynamic image deformation, for which it uses a relatively simple computation that does not require high-level knowledge about the detailed physics of liquid deformation.
Delgado, Rafael L; Llanes-Estrada, Felipe J
2015-01-01
If the Electroweak Symmetry Breaking Sector turns out to be strongly interacting, the actively investigated effective theory for longitudinal gauge bosons plus Higgs can be efficiently extended to cover the regime of saturation of unitarity (where the perturbative expansion breaks down). This is achieved by dispersion relations, whose subtraction constants and left cut contribution can be approximately obtained in different ways giving rise to different unitarization procedures. We illustrate the ideas with the Inverse Amplitude Method, one version of the N/D method and another improved version of the K-matrix. In the three cases we get partial waves which are unitary, analytical with the proper left and right cuts and in some cases poles in the second Riemann sheet that can be understood as dynamically generated resonances. In addition they reproduce at Next to Leading Order (NLO) the perturbative expansion for the five partial waves not vanishing (up to J=2) and they are renormalization scale ($\\mu$) indepe...
Modeling Gravitational Waves to Test GR Dispersion and Polarization
Tso, Rhondale; Chen, Yanbei; Isi, Maximilliano
2017-01-01
Given continued observation runs from the Laser Interferometer Gravitational-Wave Observatory Scientific Collaboration, further gravitational wave (GW) events will provide added constraints on beyond-general relativity (b-GR) theories. One approach, independent of the GW generation mechanism at the source, is to look at modification to the GW dispersion and propagation, which can accumulate over vast distances. Generic modification of GW propagation can also, in certain b-GR theories, impact the polarization content of GWs. To this end, a comprehensive approach to testing the dispersion and polarization content is developed by modeling anisotropic deformations to the waveforms' phase, along with birefringence effects and corollary consequences for b-GR polarizations, i.e., breathing, vector, and longitudinal modes. Such an approach can be mapped to specific theories like Lorentz violation, amplitude birefringence in Chern-Simons, and provide hints at additional theories to be included. An overview of data analysis routines to be implemented will also be discussed.
Kim, Ji-hyun; Han, Jae-Ho; Jeong, Jichai
2016-05-01
The commonly employed calibration methods for laboratory-made spectrometers have several disadvantages, including poor calibration when the number of characteristic spectral peaks is low. Therefore, we present a wavelength calibration method using relative k-space distribution with low coherence interferometer. The proposed method utilizes an interferogram with a perfect sinusoidal pattern in k-space for calibration. Zero-crossing detection extracts the k-space distribution of a spectrometer from the interferogram in the wavelength domain, and a calibration lamp provides information about absolute wavenumbers. To assign wavenumbers, wavelength-to-k-space conversion is required for the characteristic spectrum of the calibration lamp with the extracted k-space distribution. Then, the wavelength calibration is completed by inverse conversion of the k-space into wavelength domain. The calibration performance of the proposed method was demonstrated with two experimental conditions of four and eight characteristic spectral peaks. The proposed method elicited reliable calibration results in both cases, whereas the conventional method of third-order polynomial curve fitting failed to determine wavelengths in the case of four characteristic peaks. Moreover, for optical coherence tomography imaging, the proposed method could improve axial resolution due to higher suppression of sidelobes in point spread function than the conventional method. We believe that our findings can improve not only wavelength calibration accuracy but also resolution for optical coherence tomography.
Deformation twinning in monazite
Energy Technology Data Exchange (ETDEWEB)
Hay, R.S.; Marshall, D.B
2003-10-20
Polycrystalline monazite (LaPO{sub 4}) was deformed at room temperature by a spherical indenter. Deformation twins were identified by TEM in 70 grains. Five twin planes were found: (100) was by far the most common; (001) and (120) were less common; (122-bar)was rare, and kinks in (120) twins were identified as irrational '(483)' twin planes. The twinning modes on these planes were inferred from the expression of twinning shear at free surfaces, predictions of classical deformation twinning theory, and various considerations of twin morphology and crystal structure. Atomic shuffle calculations that allow formation of either a glide plane or a mirror plane at the twin interface were used to analyze twin modes. The inferred twin modes all have small atomic shuffles. For (001) twins, the smallest shuffles were obtained with a glide plane at the interface, with displacement vector R=((1)/(2))[010]. The results do not uniquely define a twin mode on (100), leaving open the possibility of more than one mode operating on this plane. Factors that may determine the operative deformation twinning modes are discussed. Crystal structure considerations suggest that the relative abundance of twinning modes may correlate with low shear modulus on the twin plane in the direction of twinning shear, and with a possible low-energy interface structure consisting of a layer of xenotime of one half-unit-cell thickness that could form at (100) and (001) twins. The three most common twins have low strains to low {sigma} coincidence site lattices (CSLs)
Azzouzi, R.
2009-04-01
Determination of recent horizontal crustal movements and deformations of African and Eurasian plates in western Mediterranean region using geodetic-GPS computations extended to 2006 (from 1997) related to NAFREF and AFREF frames. By: R. Azzouzi*, M. Ettarid*, El H. Semlali*, et A. Rimi+ * Filière de Formation en Topographie Institut Agronomique et Vétérinaire Hassan II B.P. 6202 Rabat-Instituts MAROC + Département de la Physique du Globe Université Mohammed V Rabat MAROC This study focus on the use of the geodetic spatial technique GPS for geodynamic purposes generally in the Western Mediterranean area and particularly in Morocco. It aims to exploit this technique first to determine the geodetic coordinates on some western Mediterranean sites. And also this technique is used to detect and to determine movements cross the boundary line between the two African and Eurasian crustal plates on some well chosen GPS-Geodynamics sites. It will allow us also to estimate crustal dynamic parameters of tension that results. These parameters are linked to deformations of terrestrial crust in the region. They are also associated with tectonic constraints of the study area. The usefulness of repeated measurements of these elements, the estimate of displacements and the determination of their temporal rates is indisputable. Indeed, sismo-tectonique studies allow a good knowledge of the of earthquake processes, their frequency their amplitude and even of their prediction in the world in general and in Moroccan area especially. They allow also contributing to guarantee more security for all most important management projects, as projects of building great works (dams, bridges, nuclear centrals). And also as preliminary study, for the most important joint-project between Europe and Africa through the Strait of Gibraltar. For our application, 23 GPS monitoring stations under the ITRF2000 reference frame are chosen in Eurasian and African plates. The sites are located around the
van Turnhout, J
2016-01-01
The dielectric spectra of colloidal systems often contain a typical low frequency dispersion, which usually remains unnoticed, because of the presence of strong conduction losses. The KK relations offer a means for converting ε' into ε″ data. This allows us to calculate conduction free ε″ spectra in which the l.f. dispersion will show up undisturbed. This interconversion can be done on line with a moving frame of logarithmically spaced ε' data. The coefficients of the conversion frames were obtained by kernel matching and by using symbolic differential operators. Logarithmic derivatives and differences of ε' and ε″ provide another option for conduction free data analysis. These difference-based functions actually derived from approximations to the distribution function, have the additional advantage of improving the resolution power of dielectric studies. A high resolution is important because of the rich relaxation structure of colloidal suspensions. The development of all-in-1 modeling facilitates the conduction free and high resolution data analysis. This mathematical tool allows the apart-together fitting of multiple data and multiple model functions. It proved also useful to go around the KK conversion altogether. This was achieved by the combined approximating ε' and ε″ data with a complex rational fractional power function. The all-in-1 minimization turned out to be also highly useful for the dielectric modeling of a suspension with the complex dipolar coefficient. It guarantees a secure correction for the electrode polarization, so that the modeling with the help of the differences ε' and ε″ can zoom in on the genuine colloidal relaxations.
Directory of Open Access Journals (Sweden)
Jan van Turnhout
2016-05-01
Full Text Available The dielectric spectra of colloidal systems often contain a typical low frequency dispersion, which usually remains unnoticed, because of the presence of strong conduction losses. The KK relations offer a means for converting into data. This allows us to calculate conduction free spectra in which the l.f. dispersion will show up undisturbed. This interconversion can be done on line with a moving frame of logarithmically spaced data. The coefficients of the conversion frames were obtained by kernel matching and by using symbolic differential operators. Logarithmic derivatives and differences of and provide another option for conduction free data analysis. These difference-based functions actually derived from approximations to the distribution function, have the additional advantage of improving the resolution power of dielectric studies. A high resolution is important because of the rich relaxation structure of colloidal suspensions. The development of all-in-1 modelling facilitates the conduction free and high resolution data analysis. This mathematical tool allows the apart-together fitting of multiple data and multiple model functions. It proved also useful to go around the KK conversion altogether. This was achieved by the combined approximating and data with a complex rational fractional power function. The all-in-1 minimization turned out to be also highly useful for the dielectric modelling of a suspension with the complex dipolar coefficient. It guarantees a secure correction for the electrode polarization, so that the modelling with the help of the differences and can zoom in on the genuine colloidal relaxations.
Turnhout, Jan
2016-05-01
The dielectric spectra of colloidal systems often contain a typical low frequency dispersion, which usually remains unnoticed, because of the presence of strong conduction losses. The KK relations offer a means for converting ɛ' into ɛ'' data. This allows us to calculate conduction free ɛ'' spectra in which the l.f. dispersion will show up undisturbed. This interconversion can be done on line with a moving frame of logarithmically spaced ɛ' data. The coefficients of the conversion frames were obtained by kernel matching and by using symbolic differential operators. Logarithmic derivatives and differences of ɛ' and ɛ'' provide another option for conduction free data analysis. These difference-based functions actually derived from approximations to the distribution function, have the additional advantage of improving the resolution power of dielectric studies. A high resolution is important because of the rich relaxation structure of colloidal suspensions. The development of all-in-1 modelling facilitates the conduction free and high resolution data analysis. This mathematical tool allows the apart-together fitting of multiple data and multiple model functions. It proved also useful to go around the KK conversion altogether. This was achieved by the combined approximating ɛ' and ɛ'' data with a complex rational fractional power function. The all-in-1 minimization turned out to be also highly useful for the dielectric modelling of a suspension with the complex dipolar coefficient. It guarantees a secure correction for the electrode polarization, so that the modelling with the help of the differences ɛ' and ɛ'' can zoom in on the genuine colloidal relaxations.
Nonlinear Dispersion Effect on Wave Transformation
Institute of Scientific and Technical Information of China (English)
LI Ruijie; Dong-Young LEE
2000-01-01
A new nonlinear dispersion relation is given in this paper, which can overcome the limitation of the intermediate minimum value in the dispersion relation proposed by Kirby and Dalrymple (1986), and which has a better approximation to Hedges＇ empirical relation than the modilied relations by Hedges (1987). Kirby and Dahymple (1987) for shallow waters. The new dispersion relation is simple in form. thus it can be used easily in practice. Meanwhile. a general explicil approximalion to the new dispersion rela tion and olher nonlinear dispersion relations is given. By use of the explicit approximation to the new dispersion relation along with the mild slope equation taking inlo account weakly nonlinear effect, a mathematical model is obtained, and it is applied to laboratory data. The results show that the model developed vith the new dispersion relation predicts wave translornation over complicated topography quite well.
Energy Technology Data Exchange (ETDEWEB)
Stirling, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1966-07-01
The {pi}{sup +} P and {pi}{sup -} P total cross sections have been measured between 500 and 1700 MeV to eliminate discrepancies in the experimental data. These new values have permitted a more precise calculation of the forward dispersion relation. These relations are well satisfied by the experimental data up to 18 GeV for charge exchange scattering. The dispersion relation for the spin-flip amplitude gives an efficient test for the phase-shift analysis solutions. (author) [French] Les sections efficaces totales {pi}{sup +} P et {pi}{sup -} P ont ete mesurees entre 500 et 1700 MeV pour eliminer les divergences qui existaient entre les resultats experimentaux anterieurs. Ces nouvelles valeurs ont permis de preciser le calcul des relations de dispersion vers l'avant. Dans le cas de la diffusion avec echange de charge ces relations sont en bon accord avec les resultats experimentaux entre 0 et 18 GeV. L'application des relations de dispersion vers l'avant a l'amplitude de spin-flip fournit une methode tres sensible pour comparer differentes series de dephasages en fonction de l'energie. (auteur)
Clemmensen, Tor Skibsted; Løgstrup, Brian Bridal; Eiskjær, Hans; Poulsen, Steen Hvitfeldt
2015-02-01
Coronary allograft vasculopathy (CAV) in heart transplant (HTx) recipients is characterized by diffuse affection of epicardial and intramyocardial coronary vessels. Despite significant CAV and anticipated affected myocardial function, left ventricular ejection fraction (LVEF) is often within the normal range, indicating the need of more sophisticated non-invasive methods to detect impaired myocardial function caused by CAV. Global longitudinal strain (GLS) represents a new echocardiographic measurement of systolic myocardial deformation. The aim of the study was to evaluate the relation between GLS measured by 2-dimensional speckle-tracking echocardiography and CAV in HTx patients. The study included 178 HTx patients and 20 healthy, age-matched individuals. All patients had an extensive echocardiographic evaluation and coronary angiography assessing CAV. CAV was classified according to International Society of Heart and Lung Transplantation classification (CAV0-3). CAV was seen in 38.8% of patients. Compared with controls (-20.6% ± 1.4%), GLS was significantly reduced according to the degree of CAV (CAV0, -16.7% ± 2.4%; CAV1, -15.2% ± 2.9%; CAV2-3, -14.0% ± 3.8%; controls, -20.6% ±1.4%; pTREND < 0.0001). In addition, we found decreasing peak systolic mitral annular velocities (pTREND = 0.0040), tissue-tracking values (pTREND = 0.0002), and LVEF according to CAV class (CAV0, 65.3% ± 5.4%; CAV2-3, 56.9% ± 11.7%; pTREND < 0.0001). The HTx population showed significant restrictive physiology compared with the control population, but no significant correlation was seen between CAV class and traditional diastolic parameters such as E/A ratio (pTREND = 0.38) or E-deceleration time (pTREND = 0.14). In contrast to LVEF and conventional pulsed mitral Doppler flow parameters used in the CAV classification, GLS relates to the presence and degree of CAV. The present results suggest GLS as a new method to be included in the monitoring of graft function in relation to CAV
Quantizing Earth surface deformations
Directory of Open Access Journals (Sweden)
C. O. Bowin
2015-03-01
Full Text Available The global analysis of Bowin (2010 used the global 14 absolute Euler pole set (62 Myr history from Gripp and Gordon (1990 and demonstrated that plate tectonics conserves angular momentum. We herein extend that analysis using the more detailed Bird (2003 52 present-day Euler pole set (relative to a fixed Pacific plate for the Earth's surface, after conversion to absolute Euler poles. Additionally, new analytical results now provide new details on upper mantle mass anomalies in the outer 200 km of the Earth, as well as an initial quantizing of surface deformations.
Seed dispersal of desert annuals.
Venable, D Lawrence; Flores-Martinez, Arturo; Muller-Landau, Helene C; Barron-Gafford, Greg; Becerra, Judith X
2008-08-01
We quantified seed dispersal in a guild of Sonoran Desert winter desert annuals at a protected natural field site in Tucson, Arizona, USA. Seed production was suppressed under shrub canopies, in the open areas between shrubs, or both by applying an herbicide prior to seed set in large, randomly assigned removal plots (10-30 m diameter). Seedlings were censused along transects crossing the reproductive suppression borders shortly after germination. Dispersal kernels were estimated for Pectocarya recurvata and Schismus barbatus from the change in seedling densities with distance from these borders via inverse modeling. Estimated dispersal distances were short, with most seeds traveling less than a meter. The adhesive seeds of P. recurvata went farther than the small S. barbatus seeds, which have no obvious dispersal adaptation. Seeds dispersed farther downslope than upslope and farther when dispersing into open areas than when dispersing into shrubs. Dispersal distances were short relative to the pattern of spatial heterogeneity created by the shrub and open space mosaic. This suggests that dispersal could contribute to local population buildup, possibly facilitating species coexistence. Overall, these results support the hypothesis that escape in time via delayed germination is likely to be more important for desert annuals than escape in space.
Oden, Michael I.; Umagu, Charles I.; Udinmwen, Efosa
2016-09-01
The most fundamental joint sets in a region are those oriented normal to the fold axis ('ac'- extension fractures) and those oriented parallel to the fold axis ('bc'- tensile fractures). Four sets of joints were observed in deformed igneous intrusives of the study area, representing two phases of Cretaceous deformation. In the Ikom -Mamfe basin, the stronger ('ac'- extension) fractures are oriented NW - SE and NNE - SSW while the weaker sets were oriented NE - SW and ESE - WNW, representing the first and second phases of Cretaceous deformation respectively. The study of the growth of the 'ac'- and 'bc' fracture sets observed on the intrusives at different locations reveals that generally the 'ac'- fracture set has a dominant percentage frequency over the 'bc'- fracture set. The high percentage frequency of the 'ac'-sets in locations with insignificant or absence of the 'bc'- set implies that the 'ac'- extension fractures are the first to initiate and probably propagated with greater ease during any episode of compression, than the 'bc'- tensile fractures. Mineralized veins hosted by the intrusives are also more pronounced in the 'ac'-sets than the 'bc'- sets. Also because of the extensive development of deformation structures in the intrusives, this study proposes the idea of syn-tectonic, rather than post-tectonic magmatic emplacement for the nine intrusives studied.
Fayngold, Moses
2013-01-01
A state of a single particle can be represented by a quantum blob in the corresponding phase space, or a patch (granule) in its 2-D subspace. Its area is frequently stated to be no less than, implying that such a granule is an indivisible quantum of the 2-D phase space. But this is generally not true, as is evident, for instance, from representation of some states in the basis of innately discrete observables like angular momentum. Here we consider some dispersed states involving the evanescent waves different from that in the total internal reflection. Such states are represented by a set of separated granules with individual areas, but with the total indeterminacy . An idealized model has a discrete Wigner function and is described by a superposition of eigenstates with eigenvalues and forming an infinite periodic array of dots on the phase plane. The question about the total indeterminacy in such state is discussed. We argue that the eigenstates corresponding to the considered EW cannot be singled out by a...
Gradient Domain Mesh Deformation - A Survey
Institute of Scientific and Technical Information of China (English)
Wei-Wei Xu; Kun Zhou
2009-01-01
This survey reviews the recent development of gradient domain mesh deformation method. Different to other deformation methods, the gradient domain deformation method is a surface-based, variational optimization method. It directly encodes the geometric details in differential coordinates, which are also called Laplacian coordinates in literature. By preserving the Laplacian coordinates, the mesh details can be well preserved during deformation. Due to the locality of the Laplacian coordinates, the variational optimization problem can be casted into a sparse linear system. Fast sparse linear solver can be adopted to generate deformation result interactively, or even in real-time. The nonlinear nature of gradient domain mesh deformation leads to the development of two categories of deformation methods: linearization methods and nonlinear optimization methods. Basically, the linearization methods only need to solve the linear least-squares system once. They are fast, easy to understand and control, while the deformation result might be suboptimal. Nonlinear optimization methods can reach optimal solution of deformation energy function by iterative updating. Since the computation of nonlinear methods is expensive, reduced deformable models should be adopted to achieve interactive performance. The nonlinear optimization methods avoid the user burden to input transformation at deformation handles, and they can be extended to incorporate various nonlinear constraints, like volume constraint, skeleton constraint, and so on. We review representative methods and related approaches of each category comparatively and hope to help the user understand the motivation behind the algorithms. Finally, we discuss the relation between physical simulation and gradient domain mesh deformation to reveal why it can achieve physically plausible deformation result.
The properties of Q-deformed hyperbolic and trigonometric functions in quantum deformation
Energy Technology Data Exchange (ETDEWEB)
Deta, U. A., E-mail: utamaalan@yahoo.co.id, E-mail: utamadeta@unesa.ac.id [Department of Physics, the State University of Surabaya (Unesa), Jl. Ketintang, Surabaya 60231 (Indonesia); Suparmi [Departmet of Physics, Sebelas Maret University, Jl. Ir. Sutami 36A Kentingan, Surakarta 57126 (Indonesia)
2015-09-30
Quantum deformation has been studied due to its relation with applications in nuclear physics, conformal field theory, and statistical-quantum theory. The q-deformation of hyperbolic function was introduced by Arai. The application of q-deformed functions has been widely used in quantum mechanics. The properties of this two kinds of system explained in this paper including their derivative. The graph of q-deformed functions presented using Matlab. The special case is given for modified Poschl-Teller plus q-deformed Scarf II trigonometry potentials.
On the Fock Transformation in Nonlinear Relativity
Bouda, A
2012-01-01
In this paper, we propose a new deformed Poisson brackets which leads to the Fock coordinate transformation by using an analogous procedure as in Deformed Special Relativity. We therefore derive the corresponding momentum transformation which is revealed to be different from previous results. Contrary to the earlier version of Fock's nonlinear relativity for which plane waves cannot be described, our resulting algebra keeps invariant for any coordinate and momentum transformations the four dimensional contraction $p_{\\mu} x^{\\mu} $, allowing therefore to associate plane waves for free particles. As in Deformed Special Relativity, we also derive a canonical transformation with which the new coordinates and momentum satisfy the usual Poisson brackets and therefore transform like the usual Lorentz vectors. Finally, we establish the dispersion relation for Fock's nonlinear relativity.
Deformations of crystal frameworks
Borcea, Ciprian S
2011-01-01
We apply our deformation theory of periodic bar-and-joint frameworks to tetrahedral crystal structures. The deformation space is investigated in detail for frameworks modelled on quartz, cristobalite and tridymite.
An Introduction to Rheology with an Emphasis on Application to Dispersions
Motyka, Andrea L.
1996-04-01
Rheology is the study of the flow and deformation of matter. This interdisciplinary field encompasses many different types of materials and applications, both in academia and industry. One of the most challenging and practical areas in which technical strides have been made is dispersion chemistry. Rheology can be used to characterize not only flow properties of a material, but also structural features. This introduction is intended to help newcomers to the field to comprehend, relatively quickly, the practical nature of rheological information and to recognize the impact of the type of internal structure on rheological properties. This article describes dispersions well-suited to rheological study and the types of interparticle forces responsible for their internal structure. The fundamental terms and concepts of rheology are explained using practical examples to illustrate how rheological techniques distinguish dispersions in terms of both flow properties and structural features.
Analysis of Mining Terrain Deformation Characteristics with Deformation Information System
Blachowski, Jan; Milczarek, Wojciech; Grzempowski, Piotr
2014-05-01
Mapping and prediction of mining related deformations of the earth surface is an important measure for minimising threat to surface infrastructure, human population, the environment and safety of the mining operation itself arising from underground extraction of useful minerals. The number of methods and techniques used for monitoring and analysis of mining terrain deformations is wide and increasing with the development of geographical information technologies. These include for example: terrestrial geodetic measurements, global positioning systems, remote sensing, spatial interpolation, finite element method modelling, GIS based modelling, geological modelling, empirical modelling using the Knothe theory, artificial neural networks, fuzzy logic calculations and other. The aim of this paper is to introduce the concept of an integrated Deformation Information System (DIS) developed in geographic information systems environment for analysis and modelling of various spatial data related to mining activity and demonstrate its applications for mapping and visualising, as well as identifying possible mining terrain deformation areas with various spatial modelling methods. The DIS concept is based on connected modules that include: the spatial database - the core of the system, the spatial data collection module formed by: terrestrial, satellite and remote sensing measurements of the ground changes, the spatial data mining module for data discovery and extraction, the geological modelling module, the spatial data modeling module with data processing algorithms for spatio-temporal analysis and mapping of mining deformations and their characteristics (e.g. deformation parameters: tilt, curvature and horizontal strain), the multivariate spatial data classification module and the visualization module allowing two-dimensional interactive and static mapping and three-dimensional visualizations of mining ground characteristics. The Systems's functionality has been presented on
Mathieu-Denoncourt, Justine; Martyniuk, Christopher J; de Solla, Shane R; Balakrishnan, Vimal K; Langlois, Valérie S
2014-01-01
Azo dyes are the most commonly used type of dye, accounting for 60-70% of all organic dye production worldwide. They are used as direct dyes in the textile, leather, printing ink, and cosmetic industries. The aim of this study was to assess the lethal and sublethal effects of the disazo dye Disperse Yellow 7 (DY7) in frogs to address a knowledge gap regarding mechanisms of toxicity and the potential for endocrine disrupting properties. Larvae of Silurana tropicalis (Western clawed frog) were exposed to DY7-contaminated water (0 to 22 μg/L) and sediment (0 to 209 μg/g) during early larval development. The concentrations used included the range of similar azo dyes found in surface waters in Canada. A significant decrease in tadpole survivorship was observed at 209 μg/g while there was a significant increase in malformations at the two highest concentrations tested in sediment. In the 209 μg/g treatment, DY7 significantly induced hsp70 (2.5-fold) and hsp90 (2.4-fold) mRNA levels, suggesting that cells required oxidative protection. The same treatment also altered the expression of two androgen-related genes: decreased ar (2-fold) and increased srd5a2 (2.6-fold). Furthermore, transcriptomics generated new hypotheses regarding the mechanisms of toxic action of DY7. Gene network analysis revealed that high concentrations of DY7 in sediment induced cellular stress-related gene transcription and affected genes associated with necrotic cell death, chromosome condensation, and mRNA processing. This study is the first to report on sublethal end points for azo dyes in amphibians, a growing environmental pollutant of concern for aquatic species.
Nanostructured Boron Nitride With High Water Dispersibility For Boron Neutron Capture Therapy
Singh, Bikramjeet; Kaur, Gurpreet; Singh, Paviter; Singh, Kulwinder; Kumar, Baban; Vij, Ankush; Kumar, Manjeet; Bala, Rajni; Meena, Ramovatar; Singh, Ajay; Thakur, Anup; Kumar, Akshay
2016-10-01
Highly water dispersible boron based compounds are innovative and advanced materials which can be used in Boron Neutron Capture Therapy for cancer treatment (BNCT). Present study deals with the synthesis of highly water dispersible nanostructured Boron Nitride (BN). Unique and relatively low temperature synthesis route is the soul of present study. The morphological examinations (Scanning/transmission electron microscopy) of synthesized nanostructures showed that they are in transient phase from two dimensional hexagonal sheets to nanotubes. It is also supported by dual energy band gap of these materials calculated from UV- visible spectrum of the material. The theoretically calculated band gap also supports the same (calculated by virtual nano lab Software). X-ray diffraction (XRD) analysis shows that the synthesized material has deformed structure which is further supported by Raman spectroscopy. The structural aspect of high water disperse ability of BN is also studied. The ultra-high disperse ability which is a result of structural deformation make these nanostructures very useful in BNCT. Cytotoxicity studies on various cell lines (Hela(cervical cancer), human embryonic kidney (HEK-293) and human breast adenocarcinoma (MCF-7)) show that the synthesized nanostructures can be used for BNCT.
Phonon dispersion relations in PrBa_{2}Cu_{3}O_{6}_{+}_{x} (x approximate to 0.2)
DEFF Research Database (Denmark)
Gardiner, C.H.; Boothroyd, A.T.; Larsen, B.H.;
2004-01-01
We report measurements of the phonon dispersion relations in nonsuperconducting, oxygen-deficient PrBa2Cu3O6+x (xapproximate to0.2) by inelastic neutron scattering. The data are compared with a model of the lattice dynamics based on a common interatomic potential. Good agreement is achieved for all...
A classification of integrable quasiclassical deformations of algebraic curves
Energy Technology Data Exchange (ETDEWEB)
Konopelchenko, B [Dipartimento di Fisica, Universita di Lecce and Sezione INFN 73100 Lecce (Italy); Alonso, L MartInez [Departamento de Fisica Teorica II, Universidad Complutense E28040 Madrid (Spain); Medina, E [Departamento de Matematicas, Universidad de Cadiz E11510 Puerto Real, Cadiz (Spain)
2006-09-08
A previously introduced scheme for describing integrable deformations of algebraic curves is completed. Lenard relations are used to characterize and classify these deformations in terms of hydrodynamic-type systems. A general solution of the compatibility conditions for consistent deformations is given and expressions for the solutions of the corresponding Lenard relations are provided.
Optical angular momentum in dispersive media
Philbin, T G
2012-01-01
The angular momentum density and flux of light in a dispersive, rotationally symmetric medium are derived from Noether's theorem. Optical angular momentum in a dispersive medium has no simple relation to optical linear momentum, even if the medium is homogeneous. A circularly polarized monochromatic beam in a homogeneous, dispersive medium carries a spin angular momentum per unit energy of $\\pm\\omega^{-1}$, as in vacuum. This result demonstrates the non-trivial interplay of dispersive contributions to optical angular momentum and energy.
Deformed metals - structure, recrystallisation and strength
DEFF Research Database (Denmark)
Hansen, Niels; Juul Jensen, Dorte
2011-01-01
It is shown how new discoveries and advanced experimental techniques in the last 25 years have led to paradigm shifts in the analysis of deformation and annealing structures of metals and in the way the strength of deformed samples is related to structural parameters. This is described in three...... sections: structural evolution by grain subdivision, recovery and recrystallisation and strength-structure relationships....
Island of Stability for Consistent Deformations of Einstein's Gravity
DEFF Research Database (Denmark)
Dietrich, Dennis D.; Berkhahn, Felix; Hofmann, Stefan;
2012-01-01
We construct deformations of general relativity that are consistent and phenomenologically viable, since they respect, in particular, cosmological backgrounds. These deformations have unique symmetries in accordance with their Minkowski cousins (Fierz-Pauli theory for massive gravitons) and incor...
Middleton, Beth; van Diggelen, Rudy; Jensen, Kai
2006-01-01
Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and
Deformable Nanolaminate Optics
Energy Technology Data Exchange (ETDEWEB)
Olivier, S S; Papavasiliou, A P; Barbee, T W; Miles, R R; Walton, C C; Cohn, M B; Chang, K
2006-05-12
We are developing a new class of deformable optic based on electrostatic actuation of nanolaminate foils. These foils are engineered at the atomic level to provide optimal opto-mechanical properties, including surface quality, strength and stiffness, for a wide range of deformable optics. We are combining these foils, developed at Lawrence Livermore National Laboratory (LLNL), with commercial metal processing techniques to produce prototype deformable optics with aperture sizes up to 10 cm and actuator spacing from 1 mm to 1 cm and with a range of surface deformation designed to be as much as 10 microns. The existing capability for producing nanolaminate foils at LLNL, coupled with the commercial metal processing techniques being used, enable the potential production of these deformable optics with aperture sizes of over 1 m, and much larger deformable optics could potentially be produced by tiling multiple deformable segments. In addition, based on the fabrication processes being used, deformable nanolaminate optics could potentially be produced with areal densities of less than 1 kg per square m for applications in which lightweight deformable optics are desirable, and deformable nanolaminate optics could potentially be fabricated with intrinsically curved surfaces, including aspheric shapes. We will describe the basic principles of these devices, and we will present details of the design, fabrication and characterization of the prototype deformable nanolaminate optics that have been developed to date. We will also discuss the possibilities for future work on scaling these devices to larger sizes and developing both devices with lower areal densities and devices with curved surfaces.
On deformations of triangulated models
De Deken, Olivier
2012-01-01
This paper is the first part of a project aimed at understanding deformations of triangulated categories, and more precisely their dg and A infinity models, and applying the resulting theory to the models occurring in the Homological Mirror Symmetry setup. In this first paper, we focus on models of derived and related categories, based upon the classical construction of twisted objects over a dg or $A_{\\infty}$-algebra. For a Hochschild 2 cocycle on such a model, we describe a corresponding "curvature compensating" deformation which can be entirely understood within the framework of twisted objects. We unravel the construction in the specific cases of derived A infinity and abelian categories, homotopy categories, and categories of graded free qdg-modules. We identify a purity condition on our models which ensures that the structure of the model is preserved under deformation. This condition is typically fulfilled for homotopy categories, but not for unbounded derived categories.
Quirk, Emma; Doggett, Adrian; Bretnall, Alison
2014-08-05
Spray Dried Dispersions (SDD) are uniform mixtures of a specific ratio of amorphous active pharmaceutical ingredient (API) and polymer prepared via a spray drying process. Volatile solvents are employed during spray drying to facilitate the formation of the SDD material. Following manufacture, analytical methodology is required to determine residual levels of the spray drying solvent and its associated impurities. Due to the high level of polymer in the SDD samples, direct liquid injection with Gas Chromatography (GC) is not a viable option for analysis. This work describes the development and validation of an analytical approach to determine residual levels of acetone and acetone related impurities, mesityl oxide (MO) and diacetone alcohol (DAA), in drug product intermediates prepared as SDDs using GC with headspace (HS) autosampling. The method development for these analytes presented a number of analytical challenges which had to be overcome before the levels of the volatiles of interest could be accurately quantified. GCHS could be used after two critical factors were implemented; (1) calculation and application of conversion factors to 'correct' for the reactions occurring between acetone, MO and DAA during generation of the headspace volume for analysis, and the addition of an equivalent amount of polymer into all reference solutions used for quantitation to ensure comparability between the headspace volumes generated for both samples and external standards. This work describes the method development and optimisation of the standard preparation, the headspace autosampler operating parameters and the chromatographic conditions, together with a summary of the validation of the methodology. The approach has been demonstrated to be robust and suitable to accurately determine levels of acetone, MO and DAA in SDD materials over the linear concentration range 0.008-0.4μL/mL, with minimum quantitation limits of 20ppm for acetone and MO, and 80ppm for DAA.
Hall, J A; Walter, G H
2014-08-01
An apparent contradiction in the ecology of cycad plants is that their seeds are known to be highly poisonous, and yet they seem well adapted for seed dispersal by animals, as shown by their visually conspicuous seed cones and large seeds presented within a brightly colored fleshy "fruit" of sarcotesta. We tested if this sarcotesta could function as a reward for cycad seed dispersal fauna, by establishing if the toxic compound cycasin, known from the seeds, is absent from the sarcotesta. The Australian cycads Macrozamia miquelii and Cycas ophiolitica were tested (N = 10 individuals per species) using gas chromatography / mass spectrometry. Cycasin was detected at 0.34 % (fresh weight) in seed endosperm of M. miquelii and 0.28 % (fresh weight) in seed endosperm of C. ophiolitica. Cycasin was absent from the sarcotesta of the same propagules (none detected in the case of M. miquelii, and trace quantities detected in sarcotesta of only four of the ten C. ophiolitica propagules). This laboratory finding was supported by field observations of native animals eating the sarcotesta of these cycads but discarding the toxic seed intact. These results suggest cycads are adapted for dispersal fauna capable of swallowing the large, heavy propagules whole, digesting the non-toxic sarcotesta flesh internally, and then voiding the toxic seed intact. Megafauna species such as extant emus or cassowaries, or extinct Pleistocene megafauna such as Genyornis, are plausible candidates for such dispersal. Cycads are an ancient lineage, and the possible antiquity of their megafaunal seed dispersal adaptations are discussed.
Merritt, M.L.
1993-01-01
The simulation of the transport of injected freshwater in a thin brackish aquifer, overlain and underlain by confining layers containing more saline water, is shown to be influenced by the choice of the finite-difference approximation method, the algorithm for representing vertical advective and dispersive fluxes, and the values assigned to parametric coefficients that specify the degree of vertical dispersion and molecular diffusion that occurs. Computed potable water recovery efficiencies will differ depending upon the choice of algorithm and approximation method, as will dispersion coefficients estimated based on the calibration of simulations to match measured data. A comparison of centered and backward finite-difference approximation methods shows that substantially different transition zones between injected and native waters are depicted by the different methods, and computed recovery efficiencies vary greatly. Standard and experimental algorithms and a variety of values for molecular diffusivity, transverse dispersivity, and vertical scaling factor were compared in simulations of freshwater storage in a thin brackish aquifer. Computed recovery efficiencies vary considerably, and appreciable differences are observed in the distribution of injected freshwater in the various cases tested. The results demonstrate both a qualitatively different description of transport using the experimental algorithms and the interrelated influences of molecular diffusion and transverse dispersion on simulated recovery efficiency. When simulating natural aquifer flow in cross-section, flushing of the aquifer occurred for all tested coefficient choices using both standard and experimental algorithms. ?? 1993.
An On-Chip RBC Deformability Checker Significantly Improves Velocity-Deformation Correlation
Directory of Open Access Journals (Sweden)
Chia-Hung Dylan Tsai
2016-10-01
Full Text Available An on-chip deformability checker is proposed to improve the velocity–deformation correlation for red blood cell (RBC evaluation. RBC deformability has been found related to human diseases, and can be evaluated based on RBC velocity through a microfluidic constriction as in conventional approaches. The correlation between transit velocity and amount of deformation provides statistical information of RBC deformability. However, such correlations are usually only moderate, or even weak, in practical evaluations due to limited range of RBC deformation. To solve this issue, we implemented three constrictions of different width in the proposed checker, so that three different deformation regions can be applied to RBCs. By considering cell responses from the three regions as a whole, we practically extend the range of cell deformation in the evaluation, and could resolve the issue about the limited range of RBC deformation. RBCs from five volunteer subjects were tested using the proposed checker. The results show that the correlation between cell deformation and transit velocity is significantly improved by the proposed deformability checker. The absolute values of the correlation coefficients are increased from an average of 0.54 to 0.92. The effects of cell size, shape and orientation to the evaluation are discussed according to the experimental results. The proposed checker is expected to be useful for RBC evaluation in medical practices.
Sandhagen, Bo; Lind, Lars
2012-01-01
It has previously been shown that a high hemoglobin value, a major determinant of whole blood viscosity (WBV), predicts cardiovascular events. One putative mechanism might be an impaired endothelial function. Erythrocyte deformability is another rheologic feature of the erythrocyte being of importance for the flow properties of the blood, especially in the capillaries. The present study evaluates the relationships between blood viscosity, erythrocyte deformability assessed as erythrocyte fluidity (EF), coronary risk and endothelial vasodilatory function. In the population-based PIVUS study (1016 subjects aged 70); endothelium-dependent vasodilation (EDV) was evaluated by the invasive forearm technique with acetylcholine given in the brachial artery and the brachial artery ultrasound technique with measurement of flow-mediated dilatation (FMD). WBV, plasma viscosity (PV) and EF were measured in a random sample of 573 subjects. WBV and PV were positively and EF negatively related to Framingham risk score. EDV was inversely related to both whole blood and plasma viscosity. FMD was not related to any rheologic variable. In multiple regression analyses WBV and EF were significantly related to EDV independently of gender, hypertension, smoking, hypercholesterolemia, obesity and diabetes. Acetylcholine-induced vasodilation in the forearm, but not FMD, was negatively related to whole blood viscosity and positively related to EF independently of traditional risk factors in elderly subjects, indicating a pathophysiological link between impaired hemorheology and coronary risk.
Angelis, Konstantinos; Albert, Jan; Mamais, Ioannis; Magiorkinis, Gkikas; Hatzakis, Angelos; Hamouda, Osamah; Struck, Daniel; Vercauteren, Jurgen; Wensing, Annemarie M J; Alexiev, Ivailo; Åsjö, Birgitta; Balotta, Claudia; Camacho, Ricardo J; Coughlan, Suzie; Griskevicius, Algirdas; Grossman, Zehava; Horban, Andrzej; Kostrikis, Leondios G; Lepej, Snjezana; Liitsola, Kirsi; Linka, Marek; Nielsen, Claus; Otelea, Dan; Paredes, Roger; Poljak, Mario; Puchhammer-Stöckl, Elisabeth; Schmit, Jean-Claude; Sönnerborg, Anders; Staneková, Danica; Stanojevic, Maja; Boucher, Charles A B; Kaplan, Lauren; Vandamme, Anne-Mieke; Paraskevis, Dimitrios
2015-06-01
Human immunodeficiency virus type 1 (HIV-1) subtype CRF01_AE originated in Africa and then passed to Thailand, where it established a major epidemic. Despite the global presence of CRF01_AE, little is known about its subsequent dispersal pattern. We assembled a global data set of 2736 CRF01_AE sequences by pooling sequences from public databases and patient-cohort studies. We estimated viral dispersal patterns, using statistical phylogeographic analysis run over bootstrap trees estimated by the maximum likelihood method. We show that Thailand has been the source of viral dispersal to most areas worldwide, including 17 of 20 sampled countries in Europe. Japan, Singapore, Vietnam, and other Asian countries have played a secondary role in the viral dissemination. In contrast, China and Taiwan have mainly imported strains from neighboring Asian countries, North America, and Africa without any significant viral exportation. The central role of Thailand in the global spread of CRF01_AE can be probably explained by the popularity of Thailand as a vacation destination characterized by sex tourism and by Thai emigration to the Western world. Our study highlights the unique case of CRF01_AE, the only globally distributed non-B clade whose global dispersal did not originate in Africa. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
Angelis, Konstantinos; Albert, Jan; Mamais, Ioannis; Magiorkinis, Gkikas; Hatzakis, Angelos; Hamouda, Osamah; Struck, Daniel; Vercauteren, Jurgen; Wensing, Annemarie M J; Alexiev, Ivailo; Åsjö, Birgitta; Balotta, Claudia; Camacho, Ricardo J.; Coughlan, Suzie; Griskevicius, Algirdas; Grossman, Zehava; Horban, Andrzej; Kostrikis, Leondios G.; Lepej, Snjezana; Liitsola, Kirsi; Linka, Marek; Nielsen, Claus; Otelea, Dan; Paredes, Roger; Poljak, Mario; Puchhammer-Stöckl, Elisabeth; Schmit, Jean Claude; Sönnerborg, Anders; Staneková, Danica; Stanojevic, Maja; Boucher, Charles A B; Kaplan, Lauren; Vandamme, Anne Mieke; Paraskevis, Dimitrios
2015-01-01
Background. Human immunodeficiency virus type 1 (HIV-1) subtype CRF01-AE originated in Africa and then passed to Thailand, where it established a major epidemic. Despite the global presence of CRF01-AE, little is known about its subsequent dispersal pattern. Methods. We assembled a global data set
DEFF Research Database (Denmark)
Pærregaard, Karsten
processes, and economic and social ties with Peru. On the other hand, it explores the comparative dimension of Peruvian migration by locating the ethnographic in-depth studies of particular migrant communities in Spain, the United States, Japan and Argentina within a broader economic and political context. ......This book presents a comparative study of Peruvian transnational migration to the United States, Spain, Japan and Argentina. It applies a multi-sited ethnographic fieldwork approach to study is the multicultural life-world of Peruvians and the economic, social, political and ritual relations...... into the receiving societies and achieve physical and social mobility, 2) to explore how the experience of migration and adaptation to their new countries of residence transforms Peruvians’ own ideas of class, nationality, ethnicity and regionality, and 3) to use the Peruvian material to discuss more general aspects...
Barbosa, L. C.
2015-09-01
Considering an idea of F. Arago in 1853 regarding light dispersion through the light ether in the interstellar space, this paper presents a new idea on an alternative interpretation of the cosmological red shift of the galaxies in the universe. The model is based on an analogy with the temporal material dispersion that occurs with light in the optical fiber core. Since intergalactic space is transparent, according to the model, this phenomenon is related to the gravitational potential existing in the whole space. Thus, it is possible to find a new interpretation to Hubble's constant. In space, light undergoes a dispersion process in its path, which is interpreted by a red shift equation of the type Δz = HL, since H = (d2n/dλ2 Δv Δλ), where H means the Hubble constant, n is the refractive index of the intergalactic space, Δλ is the spectral width of the extragalactic source, and Δv is the variation of the speed of light caused by the gravitational potential. We observe that this "constant" is governed by three new parameters. Light traveling the intergalactic space undergoes red shift due to this mechanism, while light amplitude decreases with time, and the wavelength always increases, thus producing the same type of behavior given by Hubble's Law. It can be demonstrated that the dark matter phenomenon is produced by the apparent speed of light of the stars on the periphery of the galaxies, without the existence of dark energy. Based on this new idea, the model of the universe is static, lacking expansion. Other phenomena may be interpreted based on this new model of the universe. We have what we call temporal gravitational dispersion of light in space produced by the variations of the speed of light, due to the presence of the gravitational potential in the whole space.
Totonchi, Ali; Guyuron, Bahman
2016-01-01
The alar rim plays an important role in nasal harmony. Alar rim flaws are common following the initial rhinoplasty. Classification of the deformities helps with diagnosis and successful surgical correction. Diagnosis of the deformity requires careful observation of the computerized or life-sized photographs. Techniques for treatment of these deformities can easily be learned with attention to detail. Copyright © 2016 Elsevier Inc. All rights reserved.
Fluctuations as stochastic deformation
Kazinski, P. O.
2008-04-01
A notion of stochastic deformation is introduced and the corresponding algebraic deformation procedure is developed. This procedure is analogous to the deformation of an algebra of observables like deformation quantization, but for an imaginary deformation parameter (the Planck constant). This method is demonstrated on diverse relativistic and nonrelativistic models with finite and infinite degrees of freedom. It is shown that under stochastic deformation the model of a nonrelativistic particle interacting with the electromagnetic field on a curved background passes into the stochastic model described by the Fokker-Planck equation with the diffusion tensor being the inverse metric tensor. The first stochastic correction to the Newton equations for this system is found. The Klein-Kramers equation is also derived as the stochastic deformation of a certain classical model. Relativistic generalizations of the Fokker-Planck and Klein-Kramers equations are obtained by applying the procedure of stochastic deformation to appropriate relativistic classical models. The analog of the Fokker-Planck equation associated with the stochastic Lorentz-Dirac equation is derived too. The stochastic deformation of the models of a free scalar field and an electromagnetic field is investigated. It turns out that in the latter case the obtained stochastic model describes a fluctuating electromagnetic field in a transparent medium.
Arzano, Michele; Kowalski-Glikman, Jerzy
2016-09-01
We construct discrete symmetry transformations for deformed relativistic kinematics based on group valued momenta. We focus on the specific example of κ-deformations of the Poincaré algebra with associated momenta living on (a sub-manifold of) de Sitter space. Our approach relies on the description of quantum states constructed from deformed kinematics and the observable charges associated with them. The results we present provide the first step towards the analysis of experimental bounds on the deformation parameter κ to be derived via precision measurements of discrete symmetries and CPT.
Odd Deformations of Super Riemann Surfaces: $\\mathcal N = 1$
Bettadapura, Kowshik
2016-01-01
In this article we study odd deformations of an $\\mathcal N =1$ super Riemann surface. We begin with odd, infinitesimal deformations with the objective being to describe the Kodaira-Spencer map for them and explore the consequences of the vanishing thereof. Our intent is to relate the deformation theory of a super Riemann surface with the obstruction theory of the deformation (itself to be thought of as a complex supermanifold). Illustrations are provided in low genus. Subsequently, we investigate deformations of higher order with a view to further understand this relation between obstruction theory and deformation theory. By way of motivation, a detailed study of odd, second order deformations is presented, leading naturally to a question on the characterisation odd deformations of any order.
Superradiant scattering of dispersive fields
Richartz, Maurício; Weinfurtner, Silke; Liberati, Stefano
2013-01-01
Motivated by analogue models of classical and quantum field theory in curved spacetimes and their recent experimental realizations, we consider wave scattering processes of dispersive fields exhibiting two extra degrees of freedom. In particular, we investigate how standard superradiant scattering processes are affected by subluminal or superluminal modifications of the dispersion relation. We analyze simple 1-dimensional toy-models based on fourth-order corrections to the standard second order wave equation and show that low-frequency waves impinging on generic scattering potentials can be amplified during the process. In specific cases, by assuming a simple step potential, we determine quantitatively the deviations in the amplification spectrum that arise due to dispersion, and demonstrate that the amplification can be further enhanced due to the presence of extra degrees of freedom. We also consider dispersive scattering processes in which the medium where the scattering takes place is moving with respect ...
Reduction of Deformations during Welding Metal Wire Mesh with Frames
Directory of Open Access Journals (Sweden)
Krawczyk R.
2016-06-01
Full Text Available The article presents an issue referring to a reduction of deformation during welding metal wire mesh into the frames. A problem of a possible reduction of deformations was described taking into account characteristics of a construction of a welded element. Technological tests and their results are provided. Technological recommendations relating to the reduction of deformations of the welded element are given.
Deformations of GR and BH thermodynamics
Krasnov, Kirill
2015-01-01
In four space-time dimensions General Relativity can be non-trivially deformed. Deformed theories continue to describe two propagating degrees of freedom, as GR. We study Euclidean black hole thermodynamics in these deformations. We use the recently developed formulation that works with SO(3) connections as well as certain matrices M of auxiliary fields. We show that the black hole entropy is given by one quarter of the horizon area as measured by the Lie algebra valued two-form MF, where F is the connection curvature. This coincides with the horizon area as measured by the metric only for the case of General Relativity.
M-theory and Deformation Quantization
Minic, D
1999-01-01
We discuss deformation quantization of the covariant, light-cone and conformal gauge-fixed p-brane actions (p>1) which are closely related to the structure of the classical and quantum Nambu brackets. It is known that deformation quantization of the Nambu bracket is not of the usual Moyal type. Yet the Nambu bracket can be quantized using the Zariski deformation quantization (discovered by Dito, Flato, Sternheimer and Takhtajan) which is based on factorization of polynomials in several real variables. We discuss a particular application of the Zariski deformed quantization in M-theory by considering the problem of a covariant formulation of Matrix theory. We propose that the problem of a covariant formulation of Matrix theory can be solved using the formalism of Zariski deformed quantization of the triple Nambu bracket.
Study on WC dispersion-strengthened copper
Institute of Scientific and Technical Information of China (English)
WANG Mengjun; ZHANG Liyong; LIU Xinyu
2004-01-01
Dispersion-strengthened copper (DSC) with WC as dispersoid was prepared by means of mechanical alloying (MA) following the traditional powder metallurgy (P/M) route. Influence of WC content on the properties of material was discussed in detail, and result shows that when the volume fraction of WC is 1.6%, the material achieves the best overall property, and a little more particle addition led to a less superior property owing to occurrence of particle agglomeration The as-sintered composite was designed to undergo a deformation of 75%. It is proved that appropriate deformation is helpful to attain a higher density and consequently better properties. Deformed material was then exposed to elevated temperature to test its effect on material. Annealing for 1 h at 1173K caused material to recover quite completely, but no obvious recrystallization was observed. It's supposed the particles handicaps motion of dislocations and material demonstrates good retention of strength with substantial improvement in elongation.
Spatiotemporal deformations of reflectionless potentials
Horsley, S. A. R.; Longhi, S.
2017-08-01
Reflectionless potentials for classical or matter waves represent an important class of scatteringless systems encountered in different areas of physics. Here we mathematically demonstrate that there is a family of non-Hermitian potentials that, in contrast to their Hermitian counterparts, remain reflectionless even when deformed in space or time. These are the profiles that satisfy the spatial Kramers-Kronig relations. We start by considering scattering of matter waves for the Schrödinger equation with an external field, where a moving potential is observed in the Kramers-Henneberger reference frame. We then generalize this result to the case of electromagnetic waves, by considering a slab of reflectionless material that both is scaled and has its center displaced as an arbitrary function of position. We analytically and numerically demonstrate that the backscattering from these profiles remains zero, even for extreme deformations. Our results indicate the supremacy of non-Hermitian Kramers-Kronig potentials over reflectionless Hermitian potentials in keeping their reflectionless property under deformation and could find applications to, e.g., reflectionless optical coatings of highly deformed surfaces based on perfect absorption.
Intracrystalline deformation of calcite
de Bresser, Hans
1991-01-01
It is well established from observations on natural calcite tectonites that intracrystalline plastic mechanisms are important during the deformation of calcite rocks in nature. In this thesis, new data are presented on fundamental aspects of deformation behaviour of calcite under conditions where 'd
Resurgent deformation quantisation
Energy Technology Data Exchange (ETDEWEB)
Garay, Mauricio, E-mail: garay91@gmail.com [Institut für Mathematik, FB 08 Physik, Mathematik und Informatik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Goursac, Axel de, E-mail: Axelmg@melix.net [Chargé de Recherche au F.R.S.-FNRS, IRMP, Université Catholique de Louvain, Chemin du Cyclotron, 2, B-1348 Louvain-la-Neuve (Belgium); Straten, Duco van, E-mail: straten@mathematik.uni-mainz.de [Institut für Mathematik, FB 08 Physik, Mathematik und Informatik, Johannes Gutenberg-Universität, 55099 Mainz (Germany)
2014-03-15
We construct a version of the complex Heisenberg algebra based on the idea of endless analytic continuation. The algebra would be large enough to capture quantum effects that escape ordinary formal deformation quantisation. -- Highlights: •We construct resurgent deformation quantisation. •We give integral formulæ. •We compute examples which show that hypergeometric functions appear naturally in quantum computations.