Dynamic Power Flow Controller: Compact Dynamic Phase Angle Regulators for Transmission Power Routing
None
2012-01-03T23:59:59.000Z
GENI Project: Varentec is developing compact, low-cost transmission power controllers with fractional power rating for controlling power flow on transmission networks. The technology will enhance grid operations through improved use of current assets and by dramatically reducing the number of transmission lines that have to be built to meet increasing contributions of renewable energy sources like wind and solar. The proposed transmission controllers would allow for the dynamic control of voltage and power flow, improving the grid’s ability to dispatch power in real time to the places where it is most needed. The controllers would work as fail-safe devices whereby the grid would be restored to its present operating state in the event of a controller malfunction instead of failing outright. The ability to affordably and dynamically control power flow with adequate fail-safe switchgear could open up new competitive energy markets which are not possible under the current regulatory structure and technology base.
A Longitudinal Assessment of Sleep Timing, Circadian Phase, and Phase Angle of Entrainment across of this descriptive analysis was to examine sleep timing, circadian phase, and phase angle of entrainment across of Entrainment across Human Adolescence. PLoS ONE 9(11): e112199. doi:10.1371/journal.pone.0112199 Editor: Steven
Geometric phase for collinear conical intersections. I. Geometric phase angle and vector potentials
Li Xuan [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, Oklahoma 73019 (United States); Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1 (Canada); Brue, Daniel A.; Blandon, Juan D.; Parker, Gregory A. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, Oklahoma 73019 (United States); Kendrick, Brian K. [Theoretical Division (T-1, MS B268), Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2011-02-14T23:59:59.000Z
We present a method for properly treating collinear conical intersections in triatomic systems. The general vector potential (gauge theory) approach for including the geometric phase effects associated with collinear conical intersections in hyperspherical coordinates is presented. The current study develops an introductory method in the treatment of collinear conical intersections by using the phase angle method. The geometric phase angle, {eta}, in terms of purely internal coordinates is derived using the example of a spin-aligned quartet lithium triatomic system. A numerical fit and thus an analytical form for the associated vector potentials are explicitly derived for this triatomic A{sub 3} system. The application of this methodology to AB{sub 2} and ABC systems is also discussed.
Weston, R.E. Jr.; Sears, T.J.; Preses, J.M. [Brookhaven National Laboratory, Upton, NY (United States)
1993-12-01T23:59:59.000Z
Research in this program is directed towards the spectroscopy of small free radicals and reactive molecules and the state-to-state dynamics of gas phase collision, energy transfer, and photodissociation phenomena. Work on several systems is summarized here.
Velarde Ruiz Esparza, Luis A.; Wang, Hongfei
2013-10-14T23:59:59.000Z
The relative phase and amplitude ratio between the ssp and ppp polarization combinations of the vibrational sum-frequency generation (SFG) response can be uniquely and accurately determined by the polarization null angle (PNA) method. In this report we show that PNA measurements of the -CN vibration in the 4-n pentyl-4'-cyanoterphenyl (5CT) Langmuir monolayer at the air/water interface yields ssp and ppp response of the same phase, while those in the 4-n-octyl-4'cyanobiphenyl (8CB) Langmuir monolayer have the opposite phase. Accordingly, the -CN group in the 5CT monolayer is tilted around 25+/-2 from the interface normal, while that in the 8CB is tilted around 57+/-2, consistent with the significant differences in the phase diagrams and hydrogen bonding SFG spectra of the two Langmuir monolayers as reported in the literature. These results also demonstrate that in SFG studies the relative phase information of the different polarization combinations, especially for the ssp and ppp, is important in the unique determination of the tilt angle and conformation of a molecular group at the interface.
Berry phase and Hannay’s angle in the Born–Oppenheimer hybrid systems
Liu, H.D. [National Laboratory of Science and Technology on Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)] [National Laboratory of Science and Technology on Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Yi, X.X. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Fu, L.B., E-mail: lbfu.iapcm@gmail.com [National Laboratory of Science and Technology on Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); HEDPS, Center for Applied Physics and Technology, Peking University, Beijing 100084 (China)
2013-12-15T23:59:59.000Z
In this paper, we investigate the Berry phase and Hannay’s angle in the Born–Oppenheimer (BO) hybrid systems and obtain their algebraic expressions in terms of one form connection. The semiclassical relation of Berry phase and Hannay’s angle is discussed. We find that, besides the usual connection term, the Berry phase of quantum BO composite system also contains a novel term brought forth by the coupling induced effective gauge potential. This quantum modification can be viewed as an effective Aharonov–Bohm effect. Moreover, the similar phenomenon is founded in Hannay’s angle of classical BO composite system, which indicates that the Berry phase and Hannay’s angle possess the same relation as the usual one. An example is used to illustrate our theory. This scheme can be used to generate artificial gauge potentials for neutral atoms. Besides, the quantum–classical hybrid BO system is also studied to compare with the results in full quantum and full classical composite systems. -- Highlights: •We have derived the Berry phase and Hannay’s angle in BO hybrid systems. •The Berry phase contains a novel term brought by the effective gauge potential. •This mechanism can be used to generate artificial gauge potentials for neutral atoms. •The relation between Hannay’s angles and Berry phases is established.
Design of an electronic phase angle meter for use with electronic analog computers
Cunningham, Allen Baxter
1957-01-01T23:59:59.000Z
DESIGN OF AN ELECTRONIC PHASE ANGLE METER FOR USE WITH ELECTRONIC ANALOG COMPUTERS A Thesis By Allen Baxter Cunningham Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment... of the requirements for the degree of MASTFR OF SCIFNCE August 1957 Ma]or Sub]ect! Electrical Engineering DESIGN OF AN ELECTRONIC PHASE ANGLE METER FOR USE WITH ELECTRONIC ANALOG COMPUTERS A Thesis Allen Baxter Cunningham Approved e to style and conte...
On imposing dynamic contact-angle boundary conditions for wall ...
S. Dong
2012-09-18T23:59:59.000Z
Aug 18, 2012 ... as level set [27,31], front tracking [36,35], volume of fluids [30], or phase field [25,
Buchenauer, C. Jerald (Los Alamos, NM)
1984-01-01T23:59:59.000Z
The quadrature phase angle .phi.(t) of a pair of quadrature signals S.sub.1 (t) and S.sub.2 (t) is digitally encoded on a real time basis by a quadrature digitizer for fractional .phi.(t) rotational excursions and by a quadrature up/down counter for full .phi.(t) rotations. The pair of quadrature signals are of the form S.sub.1 (t)=k(t) sin .phi.(t) and S.sub.2 (t)=k(t) cos .phi.(t) where k(t) is a signal common to both. The quadrature digitizer and the quadrature up/down counter may be used together or singularly as desired or required. Optionally, a digital-to-analog converter may follow the outputs of the quadrature digitizer and the quadrature up/down counter to provide an analog signal output of the quadrature phase angle .phi.(t).
Buchenauer, C.J.
1981-09-23T23:59:59.000Z
The quadrature phase angle phi (t) of a pair of quadrature signals S/sub 1/(t) and S/sub 2/(t) is digitally encoded on a real time basis by a quadrature digitizer for fractional phi (t) rotational excursions and by a quadrature up/down counter for full phi (t) rotations. The pair of quadrature signals are of the form S/sub 1/(t) = k(t) sin phi (t) and S/sub 2/(t) = k(t) cos phi (t) where k(t) is a signal common to both. The quadrature digitizer and the quadrature up/down counter may be used together or singularly as desired or required. Optionally, a digital-to-analog converter may follow the outputs of the quadrature digitizer and the quadrature up/down counter to provide an analog signal output of the quadrature phase angle phi (t).
Slow dynamics of a colloidal lamellar phase
Doru Constantin; Patrick Davidson; Éric Freyssingeas; Anders Madsen
2015-04-06T23:59:59.000Z
We used x-ray photon correlation spectroscopy to study the dynamics in the lamellar phase of a platelet suspension as a function of the particle concentration. We measured the collective diffusion coefficient along the director of the phase, over length scales down to the interparticle distance, and quantified the hydrodynamic interaction between the particles. This interaction sets in with increasing concentration and can be described qualitatively by a simplified model. No change in the microscopic structure or dynamics is observed at the transition between the fluid and the gel-like lamellar phases.
Dynamically Reconfiguring through Phase Detection on FPGA
Giorgi, Roberto
-grained reconfiguration that can be reconfigured to adapt to the applications' behavior. We use MicroBlaze as a general-purpose reconfiguration on the FPGA. KEYWORDS: RECONFIGURABLE; HARDWARE; PHASE CLASSIFICATION 1. Introduction Nowadays adapt to the application needs for obtaining more efficiency. The problem is how to dynamically monitor
The "magic" angle in the self-assembly of colloids suspended in a nematic host phase
Sergej Schlotthauer; Tillmann Stieger; Michael Melle; Marco G. Mazza; Martin Schoen
2015-05-21T23:59:59.000Z
Using extensive Monte Carlo (MC) simulations of colloids immersed in a nematic liquid crystal we compute an effective interaction potential via the local nematic director field and its associated order parameter. The effective potential consists of a local Landau-de Gennes (LdG) and a Frank elastic contribution. Molecular expressions for the LdG expansion coefficients are obtained via classical density functional theory (DFT). The DFT result for the LdG parameter $A$ is improved by locating the phase transition through finite-size scaling theory. We consider effective interactions between a pair of homogeneous colloids with Boojum defect topology. In particular, colloids attract each other if the angle between their center-of-mass distance vector and the far-field nematic director is about $30^{\\circ}$ which settles a long-standing discrepancy between theory and experiment. Using the effective potential in two-dimensional MC simulations we show that self-assembled structures formed by the colloids are in excellent agreement with experimental data.
Phase control of intermittency in dynamical systems Samuel Zambrano,1
Rey Juan Carlos, Universidad
Phase control of intermittency in dynamical systems Samuel Zambrano,1 Inés P. Mariño,1 Francesco has been proved in periodically driven chaotic systems is phase control of chaos 10 that the intermittency at an interior crisis in a dynamical system can be controlled by a phase control scheme. We give
Bounds on the Neutrino Mixing Angles and CP Phase for an SO(10) Model with Lopsided Mass Matrices
Carl H. Albright
2005-07-06T23:59:59.000Z
The bounds on the neutrino mixing angles and CP Dirac phase for an SO(10) model with lopsided mass matrices, arising from the presence of ${\\bf 16}_H$ and $\\bar{\\bf 16}_H$ Higgs representations, are studied by variation of the one real and three unknown complex input parameters for the right-handed Majorana neutrino mass matrix. The scatter plots obtained favor nearly maximal atmospheric neutrino mixing, while the reactor neutrino mixing lies in the range $10^{-5} \\lsim \\sin^2 \\theta_{13} \\lsim 1 \\times 10^{-2}$ with values greater than $10^{-3}$ most densely populated. A rather compelling scenario within the model follows, if we restrict the three unknown complex parameters to their imaginary axes and set two of them equal. We then find the scatter plots are reduced to narrow bands, as the mixing angles and CP phase become highly correlated and predictive. The bounds on the mixing angles and phase then become $0.45 \\lsim \\sin^2 \\theta_{23} \\lsim 0.55$, $0.38 \\lsim \\tan^2 \\theta_{12} \\lsim 0.50$, $0.002 \\lsim \\sin^2 \\theta_{13} \\lsim 0.003$, and $60^\\circ \\lsim \\pm \\delta_{CP} \\lsim 85^\\circ$. Moreover, successful leptogenesis and subsequent baryogenesis are also obtained, with $\\eta_B$ increasing from $(2.7 to 6.3) \\times 10^{-10}$ as $\\sin^2 \\theta_{23}$ increases from 0.45 to 0.55.
Amplitude and phase beam shaping for the highest sensitivity in side-wall angle detection
Cisotto, Luca
2015-01-01T23:59:59.000Z
In optical metrology, grating-like structures are used as tools to evaluate the performance of lithographic techniques. In particular, several shape parameters characterize those structures. One of them, termed side-wall angle, suffers from a considerable high error estimation. Using mathematical optimization, we investigated whether a properly shaped beam could increase the ability to detect tiny changes of this angle. This paper describes the theoretical formulation used to calculate the optimized beam and compares its performance with the case of a plane wave. We found that the sensitivity decreases with increasing slope angles, but even so its trend is better than in the plane wave case. Still, such an optimization process needs to be extended to the more general vectorial case.
Phase dynamics and particle production in preheating
Charters, T. [Departamento de Mecanica/Seccao de Matematica, Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1, P-1949-014 Lisbon (Portugal) and Centro de Fisica Teorica e Computacional da Universidade de Lisboa, Avenida Professor Gama Pinto 2, P-1649-003 Lisbon (Portugal); Nunes, A.; Mimoso, J.P. [Departamento de Fisica, Faculdade de Ciencias da Universidade de Lisboa and Centro de Fisica Teorica e Computacional da Universidade de Lisboa, Avenida Professor Gama Pinto 2, P-1649-003 Lisbon (Portugal)
2005-04-15T23:59:59.000Z
We study a simple model of a massive inflaton field {phi} coupled to another scalar field {chi} with interaction term g{sup 2}{phi}{sup 2}{chi}{sup 2}. We use the theory developed by Kofman et al. [L. Kofman, A. D. Linde, and A. A. Starobinsky, Phys. Rev. D 56, 3258 (1997).] for the first stage of preheating to give a full description of the dynamics of the {chi} field modes, including the behavior of the phase, in terms of the iteration of a simple family of circle maps. The parameters of this family of maps are a function of time when expansion of the Universe is taken into account. With this more detailed description, we obtain a systematic study of the efficiency of particle production as a function of the inflaton field and coupling parameters, and we find that for g < or approx. 3x10{sup -4} the broad resonance ceases during the first stage of preheating.
Mesoscale modeling of phase transition dynamics of thermoresponsive polymers
Li, Zhen; Li, Xuejin; Karniadakis, George Em
2015-01-01T23:59:59.000Z
We present a non-isothermal mesoscopic model for investigation of the phase transition dynamics of thermoresponsive polymers. Since this model conserves energy in the simulations, it is able to correctly capture not only the transient behavior of polymer precipitation from solvent, but also the energy variation associated with the phase transition process. Simulations provide dynamic details of the thermally induced phase transition and confirm two different mechanisms dominating the phase transition dynamics. A shift of endothermic peak with concentration is observed and the underlying mechanism is explored.
Phase Separation Dynamics in Isotropic Ion-Intercalation Particles
Zeng, Yi
Lithium-ion batteries exhibit complex nonlinear dynamics, resulting from diffusion and phase transformations coupled to ion-intercalation reactions. Using the recently developed Cahn--Hilliard reaction (CHR) theory, we ...
Nicolas Puech; Serge Mora; Ty Phou; Gregoire Porte; Jacques Jestin; Julian Oberdisse
2010-12-04T23:59:59.000Z
The effect of silica nanoparticles on transient microemulsion networks made of microemulsion droplets and telechelic copolymer molecules in water is studied, as a function of droplet size and concentration, amount of copolymer, and nanoparticle volume fraction. The phase diagram is found to be affected, and in particular the percolation threshold characterized by rheology is shifted upon addition of nanoparticles, suggesting participation of the particles in the network. This leads to a peculiar reinforcement behaviour of such microemulsion nanocomposites, the silica influencing both the modulus and the relaxation time. The reinforcement is modelled based on nanoparticles connected to the network via droplet adsorption. Contrast-variation Small Angle Neutron Scattering coupled to a reverse Monte Carlo approach is used to analyse the microstructure. The rather surprising intensity curves are shown to be in good agreement with the adsorption of droplets on the nanoparticle surface.
Mixing angle and phase correlations from A5 with generalised CP and their prospects for discovery
Ballett, Peter; Turner, Jessica
2015-01-01T23:59:59.000Z
The observed leptonic mixing pattern could be explained by the presence of a discrete flavour symmetry broken into residual subgroups at low energies. In this scenario, a residual generalised CP symmetry allows the parameters of the PMNS matrix, including Majorana phases, to be predicted in terms of a small set of input parameters. In this article, we study the mixing parameter correlations arising from the symmetry group A5 including generalised CP subsequently broken into all of its possible residual symmetries. Focusing on those patterns which satisfy present experimental bounds, we then provide a detailed analysis of the measurable signatures accessible to the planned reactor, superbeam and neutrinoless double beta decay experiments. We also discuss the role which could be played by high-precision measurements from longer term projects such as the Neutrino Factory. This work provides a concrete example of how the synergies of the upcoming experimental programme allow flavour symmetric models to be thoroug...
Dynamic Phase Filtering with Integrated Optical Ring Resonators
Adams, Donald Benjamin
2011-10-21T23:59:59.000Z
to perform better with non-linear frequency chirps. This work shows how dynamically tunable integrated optical ring resonators are able to produce such phase changes to a signal in an effective manner and offer new possibilities for the detection of phase-modulated...
Baglioni, P [University of Florence; Chen, Wei-Ren [ORNL; Falus, Peter [ORNL; Faraone, Antonio [National Institute of Standards and Technology (NIST); Fratini, Emiliano [University of Florence; Hong, Kunlun [ORNL; Liu, Yun [National Institute of Standards and Technology (NIST); Porcar, L. [National Institute of Standards and Technology (NIST)
2012-01-01T23:59:59.000Z
Recently experiments that combine both small angle neutron scattering (SANS) and Neutron Spin Echo (NSE) have demonstrated that dynamic clusters can form in concentrated lysozyme solutions when there is a right combination of a short-ranged attraction and a long-ranged electrostatic repulsion. In this paper, we study the temperature effect on the dynamic cluster formation and try to pinpoint the transition concentration from a monomer phase to a cluster phase. Interestingly at even a relatively high concentration (10 % mass fraction), despite the significant change of the SANS patterns that are associated with the change of the short-ranged attraction among proteins, the normalized short-time self-diffusion coefficient is not affected. This is interpreted due to the fact that there is no cluster formation at this condition. However, at larger concentrations such as 17.5 % and 22.5 % mass fraction, we show that the average hydrodynamic radius increase significantly and causes a large decrease of the normalized self-diffusion coefficient when the temperature is changed from 25 oC to 5 oC indicating the formation of dynamic clusters in solution.
Nuclear chiral dynamics and phases of QCD
Wolfram Weise
2012-01-04T23:59:59.000Z
This presentation starts with a brief review of our current picture of QCD phases, derived from lattice QCD thermodynamics and from models based on the symmetries and symmetry breaking patterns of QCD. Typical approaches widely used in this context are the PNJL and chiral quark-meson models. It is pointed out, however, that the modeling of the phase diagram in terms of quarks as quasiparticles misses important and well known nuclear physics constraints. In the hadronic phase of QCD governed by confinement and spontaneously broken chiral symmetry, in-medium chiral effective field theory is the appropriate framework, with pions and nucleons as active degrees of freedom. Nuclear chiral thermodynamics is outlined and the liquid-gas phase transition is described. The density and temperature dependence of the chiral condensate is deduced. As a consequence of two- and three-body correlations in the nuclear medium, no tendency towards a first-order chiral phase transition is found at least up to twice the baryon density of normal nuclear matter and up to temperatures of about 100 MeV. Isospin-asymmetric nuclear matter and neutron matter are also discussed. An outlook is given on new tightened constraints for the equation-of-state of cold and highly compressed matter as implied by a recently observed two-solar-mass neutron star.
Switching dynamics in cholesteric blue phases
A. Tiribocchi; G. Gonnella; D. Marenduzzo; E. Orlandini
2011-03-30T23:59:59.000Z
Blue phases are networks of disclination lines, which occur in cholesteric liquid crystals near the transition to the isotropic phase. They have recently been used for the new generation of fast switching liquid crystal displays. Here we study numerically the steady states and switching hydrodynamics of blue phase I (BPI) and blue phase II (BPII) cells subjected to an electric field. When the field is on, there are three regimes: for very weak fields (and strong anchoring at the boundaries) the blue phases are almost unaffected, for intermediate fields the disclinations twist (for BPI) and unzip (for BPII), whereas for very large voltages the network dissolves in the bulk of the cell. Interestingly, we find that a BPII cell can recover its original structure when the field is switched off, whereas a BPI cell is found to be trapped more easily into metastable configurations. The kinetic pathways followed during switching on and off entails dramatic reorganisation of the disclination networks. We also discuss the effect of changing the director field anchoring at the boundary planes and of varying the direction of the applied field.
Morinaga, Atsuo; Toriyama, Koichi; Narui, Hirotaka; Aoki, Takatoshi; Imai, Hiromitsu [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba 278-8510 (Japan)
2011-05-15T23:59:59.000Z
Berry's phase for a whole turn in a conical rotation of the magnetic field with a semiangle {theta} has been clearly manifested free from the dynamical phase shift using the magnetic-field-insensitive two-photon transitions between sodium-ground hyperfine states having different signs of the g factors. The solid angles for states with a positive g factor and with a negative g factor are verified to be 2{pi}(1-cos{theta}) and -2{pi}(1+cos{theta}), respectively, for a right-handed rotation of a magnetic field and a semiangle of 0{<=}{theta}{<=}{pi}/2.
Quantum phase communication channels in the presence of static and dynamical phase diffusion
Jacopo Trapani; Berihu Teklu; Stefano Olivares; Matteo G. A. Paris
2015-05-12T23:59:59.000Z
We address quantum communication channels based on phase modulation of coherent states and analyze in details the effects of static and dynamical (stochastic) phase diffusion. We evaluate mutual information for an ideal phase receiver and for a covariant phase-space-based receiver, and compare their performances by varying the number of symbols in the alphabet and/or the overall energy of the channel. Our results show that phase communication channels are generally robust against phase noise, especially for large alphabets in the low energy regime. In the presence of dynamical (non-Markovian) noise the mutual information is preserved by the time correlation of the environment, and when the noise spectra is detuned with respect to the information carrier, revivals of mutual information appears.
Dynamic Phase Transition, Enhanced Reaction Rate, and
Rikvold, Per Arne
is a CO, they react [CO + O CO2(g)] These dynamical rules fully define the model. Its properties on a crystal surface by Langmuir-Hinshelwood mechanism: CO(g)+S CO(a) O2 + 2S 2O(a) CO(a) + O(a) CO2(g) + 2S been observed experimentally for high enough temperatures. Add CO desorption rate k to mimic
Garnier, Josselin
multiscale analysis the hotspot dynamics during the deceleration phase of inertial confinement December 2004) paper is devoted study deceleration phase inertial confinement capsules. First self. [DOI: 10.1063/1.1825389] INTRODUCTION dynamics the deceleration phase inertial con finement fusion
Zhang, Hongxin [ORNL; He, Lilin [ORNL; Melnichenko, Yuri B [ORNL; Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL
2012-01-01T23:59:59.000Z
We report on the use of in-situ small angle neutron scattering (SANS) technique to study the phase behavior of hydrogen confined in narrow pores of ultramicroporous carbon (UMC) with a very large surface area (2630 m2/g) and pore volume (1.3 cm3/g). The effect of pore size and pressure on hydrogen adsorbed on UMC at room temperature and pressures up to ~200 bar were investigated. In a previous experiment, we have measured the density of adsorbed H2 gas in the nanopores and mesopores of polyfurfuryl alcohol-derived activated carbon (PFAC) by SANS techniques. Here, a comparative SANS study between the UMC and PFAC was conducted in order to further investigate the densification of H2 as a function of pore size and pressure. Initial results suggest that the density of confined H2 in both UMC and PFAC is considerably higher than that of the bulk hydrogen gas. The density is systematically higher in the narrow pores and decreases with increasing pore size. These results clearly demonstrate the advantage of adsorptive storage over compressed gas storage and emphasize the greater efficiency of micropores over mesopores in the adsorption process, which can be used to guide the development of new carbon adsorbents tailored for maximum H2 storage capacities at near-ambient temperatures.
Fujisawa, Tetsuro; Takahashi, Satoshi [RIKEN Harima Institute, SPring-8 Center, Laboratory for Biometal Science, Hyogo 679-5148 (Japan); Institute for Protein Research, Osaka University Suita Osaka 565-0871/CREST, JST (Japan)
2007-03-30T23:59:59.000Z
The polypeptide collapse is an essential dynamics in protein folding. To understand the mechanism of the collapse, in situ observation of folding by various probes is necessary. The changes in secondary and tertiary structures in the folding process of globular proteins, whose chain lengths are less than 300 polypeptides, were observed by circular dichrosim and intrinsic fluorescence spectroscopies, respectively. On the other hand, those in protein compactness could be only detected by using time-resolved synchrotron x-ray small-angle scattering technique. The observed dynamics for several proteins with different topologies suggested a common folding mechanism termed 'collapse and search' dynamics, in which the polypeptide collapse precedes the formation of the native contact formation. In 'collapse and search' dynamics, the most outstanding feature lied in the compactness of the initial intermediates. The collapsed intermediates demonstrated the scaling relationship between radius of gyration (Rg) and chain length with a scaling exponent of 0.35 {+-} 0.11, which is close to the value (1/3) predicted by mechano-statistical theory for the collapsed globules of polymers in poor solvent. Thus, it was suggested that the initial collapse is caused by the coil-globule transition of polymers. Since the collapse is essential to the folding of larger proteins, further investigations on the collapse likely lead to an important insight into the protein folding phenomena.
Hall,G.E.; Sears, T.J.
2009-04-03T23:59:59.000Z
This research is carried out as part of the Gas-Phase Molecular Dynamics program in the Chemistry Department at Brookhaven National Laboratory. High-resolution spectroscopy, augmented by theoretical and computational methods, is used to investigate the structure and collision dynamics of chemical intermediates in the elementary gas-phase reactions involved in combustion chemistry. Applications and methods development are equally important experimental components of this work.
Gas-Phase Molecular Dynamics: Theoretical Studies In Spectroscopy and Chemical Dynamics
Yu H. G.; Muckerman, J.T.
2012-05-29T23:59:59.000Z
The main goal of this program is the development and application of computational methods for studying chemical reaction dynamics and molecular spectroscopy in the gas phase. We are interested in developing rigorous quantum dynamics algorithms for small polyatomic systems and in implementing approximate approaches for complex ones. Particular focus is on the dynamics and kinetics of chemical reactions and on the rovibrational spectra of species involved in combustion processes. This research also explores the potential energy surfaces of these systems of interest using state-of-the-art quantum chemistry methods, and extends them to understand some important properties of materials in condensed phases and interstellar medium as well as in combustion environments.
Phase Space Formulation of Population Dynamics in Ecology
Jesus Martinez-Linares
2013-04-08T23:59:59.000Z
A phase space theory for population dynamics in Ecology is presented. This theory applies for a certain class of dynamical systems, that will be called M-systems, for which a conserved quantity, the M-function, can be defined in phase space. This M-function is the generator of time displacements and contains all the dynamical information of the system. In this sense the M-function plays the role of the hamiltonian function for mechanical systems. In analogy with Hamilton theory we derive equations of motion as derivatives over the resource function in phase space. A M-bracket is defined which allows one to perform a geometrical approach in analogy to Poisson bracket of hamiltonian systems. We show that the equations of motion can be derived from a variational principle over a functional J of the trajectories. This functional plays for M-systems the same role than the action S for hamiltonian systems. Finally, three important systems in population dynamics, namely, Lotka-Volterra, self-feeding and logistic evolution, are shown to be M-systems.
Effect of Three-Phase Contact Line Topology on Dynamic Contact Angles on Heterogeneous Surfaces
Panchagnula, Mahesh
surfaces. The Cassie-Baxter theory arises from a minimization of the global Gibbs free energy of the system mobility. For both the regimes, the system Gibbs free energy consists of the surface energies of the liquid the interfacial area. Several studies have applied the free energy balance of the liquid-solid, liquid- vapor
Measurement of the phase diffusion dynamics in the micromaser
Casagrande, Federico; Lulli, A; Bonifacio, R; Solano, E; Walther, H
2003-01-01T23:59:59.000Z
We propose a realistic scheme for measuring the micromaser linewidth by monitoring the phase diffusion dynamics of the cavity field. Our strategy consists in exciting an initial coherent state with the same photon number distribution as the micromaser steady-state field, singling out a purely diffusive process in the system dynamics. After the injection of a counter-field, measurements of the population statistics of a probe atom allow us to derive the micromaser linewidth. Our proposal aims at solving a classic and relevant decoherence problem in cavity quantum electrodynamics, allowing to establish experimentally the distinctive features appearing in the micromaser spectrum due to the discreteness of the electromagnetic field.
Measurement of the phase diffusion dynamics in the micromaser
F. Casagrande; A. Ferraro; A. Lulli; R. Bonifacio; E. Solano; H. Walther
2002-08-05T23:59:59.000Z
We propose a realistic scheme for measuring the micromaser linewidth by monitoring the phase diffusion dynamics of the cavity field. Our strategy consists in exciting an initial coherent state with the same photon number distribution as the micromaser steady-state field, singling out a purely diffusive process in the system dynamics. After the injection of a counter-field, measurements of the population statistics of a probe atom allow us to derive the micromaser linewidth. Our proposal aims at solving a classic and relevant decoherence problem in cavity quantum electrodynamics, allowing to establish experimentally the distinctive features appearing in the micromaser spectrum due to the discreteness of the electromagnetic field.
UNIVERSALITY OF PHASE TRANSITION DYNAMICS: TOPOLOGICAL DEFECTS FROM SYMMETRY BREAKING
Zurek, Wojciech H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Del Campo, Adolfo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2014-02-13T23:59:59.000Z
In the course of a non-equilibrium continuous phase transition, the dynamics ceases to be adiabatic in the vicinity of the critical point as a result of the critical slowing down (the divergence of the relaxation time in the neighborhood of the critical point). This enforces a local choice of the broken symmetry and can lead to the formation of topological defects. The Kibble-Zurek mechanism (KZM) was developed to describe the associated nonequilibrium dynamics and to estimate the density of defects as a function of the quench rate through the transition. During recent years, several new experiments investigating formation of defects in phase transitions induced by a quench both in classical and quantum mechanical systems were carried out. At the same time, some established results were called into question. We review and analyze the Kibble-Zurek mechanism focusing in particular on this surge of activity, and suggest possible directions for further progress.
Ultrafast dynamics of the laser-induced solid-to-liquid phase transition in aluminum
Mazur, Eric
Ultrafast dynamics of the laser-induced solid-to-liquid phase transition in aluminum A thesis dynamics of the laser-induced solid-to-liquid phase transition in aluminum Eric Mazur Maria Kandyla Abstract This dissertation reports the ultrafast dynamics of aluminum during the solid-to- liquid phase
Hall G. E.; Goncharov, V.
2012-05-29T23:59:59.000Z
This research is carried out as part of the Gas-Phase Molecular Dynamics program in the Chemistry Department at Brookhaven National Laboratory. Chemical intermediates in the elementary gas-phase reactions involved in combustion chemistry are investigated by high resolution spectroscopic tools. Production, reaction, and energy transfer processes are investigated by transient, double resonance, polarization and saturation spectroscopies, with an emphasis on technique development and connection with theory, as well as specific molecular properties.
Hall, G.E.
2011-05-31T23:59:59.000Z
This research is carried out as part of the Gas-Phase Molecular Dynamics program in the Chemistry Department at Brookhaven National Laboratory. Chemical intermediates in the elementary gas-phase reactions involved in combustion chemistry are investigated by high resolution spectroscopic tools. Production, reaction, and energy transfer processes are investigated by transient, double resonance, polarization and saturation spectroscopies, with an emphasis on technique development and connection with theory, as well as specific molecular properties.
arXiv:cond-mat/0505042v12May2005 The two-angle model and the phase diagram
Heermann, Dieter W.
open structures; so it is surmised that the linker histones act near the entry-exit point of the DNA, 9]. Increasing the salt concentration decreases the entry-exit angle of the stem as it reduces around it). The DNA entry-exit side faces inward towards the axis of the solenoid. The linker DNA
Collective Phase Chaos in the Dynamics of Interacting Oscillator Ensembles
Sergey P. Kuznetsov; Arkady Pikovsky; Michael Rosenblum
2010-12-03T23:59:59.000Z
We study chaotic behavior of order parameters in two coupled ensembles of self-sustained oscillators. Coupling within each of these ensembles is switched on and off alternately, while the mutual interaction between these two subsystems is arranged through quadratic nonlinear coupling. We show numerically that in the course of alternating Kuramoto transitions to synchrony and back to asynchrony, the exchange of excitations between two subpopulations proceeds in such a way that their collective phases are governed by an expanding circle map similar to the Bernoulli map. We perform the Lyapunov analysis of the dynamics and discuss finite-size effects.
Texas at Austin, University of
are expected to be effectively utilized in modern radar and communication systems. These systems cover-space sections that imply inevitable diffraction and loss issues. Phase control systems [17] exploit-free steering, increased scan flexibility in two dimensions, precise elemental phase and amplitude control
Phase Diagram of Dynamical Twisted Mass Wilson Fermions at Finite Isospin Chemical Potential
Janssen, Oliver; Splittorff, K; Verbaarschot, Jacobus J M; Zafeiropoulos, Savvas
2015-01-01T23:59:59.000Z
We consider the phase diagram of twisted mass Wilson fermions of two-flavor QCD in the parameter space of the quark mass, the isospin chemical potential, the twist angle and the lattice spacing. This work extends earlier studies in the continuum and those at zero chemical potential. We evaluate the phase diagram as well as the spectrum of the (pseudo-)Goldstone bosons using the chiral Lagrangian for twisted mass Wilson fermions at non-zero isospin chemical potential. The phases are obtained from a mean field analysis. At zero twist angle we find that already an infinitesimal isospin chemical potential destroys the Aoki phase. The reason is that in this phase we have massless Goldstone bosons with a non-zero isospin charge. At finite twist angle only two different phases are present, one phase which is continuously connected to the Bose condensed phase at non-zero chemical potential and another phase which is continuously connected to the normal phase. For either zero or maximal twist the phase diagram is more...
Phase and Amplitude dynamics of nonlinearly coupled oscillators
P. Cudmore; C. A. Holmes
2014-12-04T23:59:59.000Z
This paper addresses the amplitude and phase dynamics of a large system non-linear coupled, non-identical damped harmonic oscillators, which is based on recent research in coupled oscillation in optomechanics. Our goal is to investigate the existence and stability of collective behaviour which occurs due to a play-off between the distribution of individual oscillator frequency and the type of nonlinear coupling. We show that this system exhibits synchronisation, where all oscillators are rotating at the same rate, and that in the synchronised state the system has a regular structure related to the distribution of the frequencies of the individual oscillators. Using a geometric description we show how changes in the non-linear coupling function can cause pitchfork and saddle-node bifurcations which create or destroy stable and unstable synchronised solutions. We apply these results to show how in-phase and anti-phase solutions are created in a system with a bi-modal distribution of frequencies.
Bayro, Marvin J.
We describe magic-angle spinning NMR experiments designed to elucidate the interstrand architecture of amyloid fibrils. Three methods are introduced for this purpose, two being based on the analysis of long-range [superscript ...
David B. Saakian; Laurent Schwartz
2012-12-04T23:59:59.000Z
We investigate the catalytic reactions model used in cell modeling. The reaction kinetic is defined through the energies of different species of molecules following random independent distribution. The related statistical physics model has three phases and these three phases emerged in the dynamics: fast dynamics phase, slow dynamic phase and ultra-slow dynamic phase. The phenomenon we found is a rather general, does not depend on the details of the model. We assume as a hypothesis that the transition between these phases (glassiness degrees) is related to cancer. The imbalance in the rate of processes between key aspects of the cell (gene regulation, protein-protein interaction, metabolical networks) creates a change in the fine tuning between these key aspects, affects the logics of the cell and initiates cancer. It is probable that cancer is a change of phase resulting from increased and deregulated metabolic reactions.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Bhatti, Kanwal Preet; El-Khatib, S.; Srivastava, Vijay; James, R. D.; Leighton, C.
2012-04-01T23:59:59.000Z
The Heusler-derived multiferroic alloy Ni50–xCoxMn??Sn?? has recently been shown to exhibit, at just above room temperature, a highly reversible martensitic phase transformation with an unusually large magnetization change. In this work the nature of the magnetic ordering above and below this transformation has been studied in detail in the critical composition range x = 6–8 via temperature-dependent (5–600 K) magnetometry and small-angle neutron scattering (SANS). We observe fairly typical paramagnetic to long-range-ordered ferromagnetic phase transitions on cooling to 420–430 K, with the expected critical spin fluctuations, followed by first-order martensitic phase transformations to a nonferromagnetic state below 360–390 K. The static magnetization reveals complex magnetism in this low-temperature nonferromagnetic phase, including a Langevin-like field dependence, distinct spin freezing near 60 K, and significant exchange bias effects, consistent with superparamagnetic blocking of ferromagnetic clusters of nanoscopic dimensions. We demonstrate that these spin clusters, whose existence has been hypothesized in a variety of martensitic alloys exhibiting competition between ferromagnetic and antiferromagnetic exchange interactions, can be directly observed by SANS. The scattering data are consistent with a liquidlike spatial distribution of interacting magnetic clusters with a mean center-to-center spacing of 12 nm. Considering the behavior of the superparmagnetism, cooling-field and temperature-dependent exchange bias, and magnetic SANS, we discuss in detail the physical form and origin of these spin clusters, their intercluster interactions, the nature of the ground-state magnetic ordering in the martensitic phase, and the implications for our understanding of such alloy systems.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Bhatti, Kanwal Preet; El-Khatib, S.; Srivastava, Vijay; James, R. D.; Leighton, C.
2012-04-01T23:59:59.000Z
The Heusler-derived multiferroic alloy Ni50–xCoxMn??Sn?? has recently been shown to exhibit, at just above room temperature, a highly reversible martensitic phase transformation with an unusually large magnetization change. In this work the nature of the magnetic ordering above and below this transformation has been studied in detail in the critical composition range x = 6–8 via temperature-dependent (5–600 K) magnetometry and small-angle neutron scattering (SANS). We observe fairly typical paramagnetic to long-range-ordered ferromagnetic phase transitions on cooling to 420–430 K, with the expected critical spin fluctuations, followed by first-order martensitic phase transformations to a nonferromagnetic state below 360–390 K. Themore »static magnetization reveals complex magnetism in this low-temperature nonferromagnetic phase, including a Langevin-like field dependence, distinct spin freezing near 60 K, and significant exchange bias effects, consistent with superparamagnetic blocking of ferromagnetic clusters of nanoscopic dimensions. We demonstrate that these spin clusters, whose existence has been hypothesized in a variety of martensitic alloys exhibiting competition between ferromagnetic and antiferromagnetic exchange interactions, can be directly observed by SANS. The scattering data are consistent with a liquidlike spatial distribution of interacting magnetic clusters with a mean center-to-center spacing of 12 nm. Considering the behavior of the superparmagnetism, cooling-field and temperature-dependent exchange bias, and magnetic SANS, we discuss in detail the physical form and origin of these spin clusters, their intercluster interactions, the nature of the ground-state magnetic ordering in the martensitic phase, and the implications for our understanding of such alloy systems.« less
Pace, D. C., E-mail: pacedc@fusion.gat.com; Fisher, R. K.; Van Zeeland, M. A. [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States); Pipes, R. [Department of Physics, University of Hawaii, Hilo, Hawaii 96720-4091 (United States)
2014-11-15T23:59:59.000Z
New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. These calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.
A Dynamic Model for Phase Transformations in 3D Samples of Shape Memory Alloys
Melnik, Roderick
A Dynamic Model for Phase Transformations in 3D Samples of Shape Memory Alloys D.R. Mahapatra and R Introduction Modelling of dynamics of phase transformations (PT) in Shape Memory Al- loys (SMAs) under which assist the researchers in designing new materials and devices by harnessing the shape memory
Approach to Equilibrium of Glauber Dynamics In the One Phase Region. I: The Attractive Case
.g temperature and magnetic field) which do not give rise to a phase transition , must have a rapid (typically close to the line of first order phase transition was proved few years ago by the authors of the presentApproach to Equilibrium of Glauber Dynamics In the One Phase Region. I: The Attractive Case F
Magic Angle Spinning NMR Reveals Sequence-Dependent Structural...
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Magic Angle Spinning NMR Reveals Sequence-Dependent Structural Plasticity, Dynamics, and the Spacer Peptide 1 Conformation in Magic Angle Spinning NMR Reveals Sequence-Dependent...
Dynamic Phase Boundaries for Compressible Fluids , Z. L. Xu
New York at Stoney Brook, State University of
is required for the study of cavitation induced by strong rarefaction waves. The robustness of the proposed of hydrodynamics and thermal effects in liquid-vapor phase transitions is en- countered in many applications-equilibrium effects. A complete macroscopic description of phase changes requires the coupling of hydrodynamics
Dynamics of photorefractive self-pumped phase-conjugate mirrors with a linear resonator
Vakhdani, M Mekhran; Rudenko, K V; Shuvalov, V V [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation)
2008-04-30T23:59:59.000Z
The phase-conjugation dynamics in a self-pumped phase-conjugate mirror (SP PCM) based on a BaTiO{sub 3} photorefractive crystal (PRC) with a linear resonator is simulated numerically. It is shown that a phased array of dynamic holograms is formed in such a SP PCM under optimal conditions, and the interference of the waves scattered by this array provides the very high stationary phase-conjugation efficiency (the nonlinear reflection coefficient and overlap integral exceeding 80% and 95%, respectively). It is found that the development of instabilities is caused both by the violation of phase relations in this array and the formation of additional dynamic holograms in the PRC in the geometry typical of a SP PCM with a semi-linear resonator and by the self-bending effect typical of PRCs. (nonlinear optical phenomena)
Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Holland, B [University of Guelph; Gray, C.G [University of Guelph; Tomberli, B [Brandon University; Katsaras, John [ORNL
2012-01-01T23:59:59.000Z
We combine molecular dynamics (MD) simulations and experiment, both small-angle neutron (SANS) and small-angle X-ray scattering (SAXS), to determine the precise structure of bilayers composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol (POPG), a lipid commonly encountered in bacterial membranes. Experiment and simulation are used to develop a one-dimensional scattering density profile (SDP) model suitable for the analysis of experimental data. The joint refinement of such data (i.e., SANS and SAXS) results in the area per lipid that is then used in the fixed-area simulations. In the final step, the direct comparison of simulated-to-experimental data gives rise to the detailed structure of POPG bilayers. From these studies we conclude that POPG s molecular area is 66.0 +/- 1.3 ^2, its overall bilayer thickness is 36.7 +/- 0.7 , and its hydrocarbon region thickness is 27.9 ( 0.6 , assuming a simulated value of 1203 ^3 for the total lipid volume.
Dynamic modeling of three-phase upflow fixed-bed reactor including pore diffusion C. Julcoura
Paris-Sud XI, Université de
Dynamic modeling of three-phase upflow fixed-bed reactor including pore diffusion C. Julcoura , R-phase upflow fixed-bed reactor are investigated using a non-isothermal heterogeneous model including gas not limiting, so that the simplest model predicts accurately the transient reactor behavior. Keywords: fixed-bed
Molecular dynamics simulation of the plastic to triclinic phase transition in clusters of SF6
Paris-Sud XI, Université de
41 Molecular dynamics simulation of the plastic to triclinic phase transition in clusters of SF6 A agrégats n'a pas été entreprise. Abstract. 2014 Clusters of 512 SF6 molecules in their condensed phases of finite systems such as clusters [2]. Liquid sulphur hexafluoride, SF6, forms on cooling what is known
Cerveny, Vlastislav
1 THE DYNAMICAL INFLUENCES FROM PHYSICAL PROPERTIES IN THE LOWER MANTLE AND POST-PEROVSKITE PHASE, Yokohama 236-0001, Japan ABSTRACT The discovery of post-perovskite phase transition near the core conductivity together with the post-perovskite transition within the framework of isochemical models We have
Melnik, Roderick
Modeling the essential atomistic influence in the phase transformation dynamics of shape memory of multivariant phase transformation in shape memory alloy has been developed. This paper is focused on linking Shape memory effects in alloys are observed due to the existence of large differences in the variants
Phase Field Dynamic Modelling of Shape Memory Alloys Based on Isogeometric Analysis
Gomez, Hector
Phase Field Dynamic Modelling of Shape Memory Alloys Based on Isogeometric Analysis Rakesh Dhote1 transformations, phase-field model, Ginzburg-Landau theory, nonlinear thermo-elasticity. Abstract. Shape Memory. Introduction Shape Memory Alloys have attracted considerable attention of physicists, engineers and mathemati
Dynamics of bulk fluctuations in a lamellar phase studied by coherent x-ray scattering
Doru Constantin; Guillaume Brotons; Tim Salditt; Eric Freyssingeas; Anders Madsen
2015-04-07T23:59:59.000Z
Using x-ray photon correlation spectroscopy, we studied the layer fluctuations in the lamellar phase of an ionic lyotropic system. We measured the relaxation rate of in-plane (undulation) fluctuations as a function of the wave vector. Static and dynamic results obtained during the same experiment were combined to yield the values of both elastic constants of the lamellar phase (compression and bending moduli) as well as that of the sliding viscosity. The results are in very good agreement with dynamic light-scattering data, validating the use of the technique in ordered phases.
Polymer dynamics in the depinned phase: metastability with logarithmic barriers
Pietro Caputo; Hubert Lacoin; Fabio Martinelli; François Simenhaus; Fabio Lucio Toninelli
2010-07-26T23:59:59.000Z
We consider the stochastic evolution of a (1 + 1)-dimensional polymer in the depinned regime. At equilibrium the system exhibits a double well structure: the polymer lies(essentially) either above or below the repulsive line. As a consequence one expects a metastable behavior with rare jumps between the two phases combined with a fast thermalization inside each phase. However the energy barrier between these two phases is only logarithmic in the system size L and therefore the two relevant time scales are only polynomial in L with no clear-cut separation between them. The whole evolution is governed by a subtle competition between the diffusive behavior inside one phase and the jumps across the energy barriers. In particular the usual scenario in which the tunneling time coincides with the exponential of the energy barrier breaks down. Our main results are: (i) a proof that the mixing time of the system lies between L^{5/2} and L^{5/2+2}; (ii) the identification of two regions associated with the positive and negative phase of the polymer together with the proof of the asymptotic exponentiality of the tunneling time between them with rate equal to a half of the spectral gap.
Laser phase noise effects on the dynamics of optomechanical resonators
Gregory A. Phelps; Pierre Meystre
2010-11-01T23:59:59.000Z
We investigate theoretically the influence of laser phase noise on the cooling and heating of a generic cavity optomechanical system. We derive the back-action damping and heating rates and the mechanical frequency shift of the radiation pressure-driven oscillating mirror, and derive the minimum phonon occupation number for small laser linewidths. We find that in practice laser phase noise does not pose serious limitations to ground state cooling. We then consider the effects of laser phase noise in a parametric cavity driving scheme that minimizes the back-action heating of one of the quadratures of the mechanical oscillator motion. Laser linewidths narrow compared to the decay rate of the cavity field will not pose any problems in an experimental setting, but broader linewidths limit the practicality of this back-action evasion method.
Effects of Phase Transition induced density fluctuations on pulsar dynamics
Bagchi, Partha; Layek, Biswanath; Srivastava, Ajit M
2015-01-01T23:59:59.000Z
We show that density fluctuations during phase transitions in pulsar cores may have non-trivial effects on pulsar timings, and may also possibly account for glitches and anti-glitches. These density fluctuations invariably lead to non-zero off-diagonal components of the moment of inertia, leading to transient wobbling of star. Thus, accurate measurements of pulsar timing and intensity modulations (from wobbling) may be used to identify the specific pattern of density fluctuations, hence the particular phase transition, occurring inside the pulsar core. Changes in quadrupole moment from rapidly evolving density fluctuations during the transition, with very short time scales, may provide a new source for gravitational waves.
Alternating-phase focusing: A model to study nonlinear dynamics
Sagalovsky, L.; Delayen, J.R.
1992-01-01T23:59:59.000Z
We discuss a new model to study alternating-phase focusing (APF). Our approach is based on representing the accelerating electric field with a continuous phase modulated traveling wave. The resulting nonlinear equations of motion can be solved analytically to predict the regions of stable APF motion. We also identify the key parameters which adequately describe the physics of APF. The model is believed to be applicable to low-{beta} ion linacs with short independently-controlled superconducting cavities being developed at ANL.
Alternating-phase focusing: A model to study nonlinear dynamics
Sagalovsky, L.; Delayen, J.R.
1992-09-01T23:59:59.000Z
We discuss a new model to study alternating-phase focusing (APF). Our approach is based on representing the accelerating electric field with a continuous phase modulated traveling wave. The resulting nonlinear equations of motion can be solved analytically to predict the regions of stable APF motion. We also identify the key parameters which adequately describe the physics of APF. The model is believed to be applicable to low-{beta} ion linacs with short independently-controlled superconducting cavities being developed at ANL.
Coherent Control of Quantum Dynamics with Sequences of Unitary Phase-Kick Pulses
Luis G. C. Rego; L. F. Santos; V. S. Batista
2010-03-22T23:59:59.000Z
Coherent optical control schemes exploit the coherence of laser pulses to change the phases of interfering dynamical pathways in order to manipulate dynamical processes. These active control methods are closely related to dynamical decoupling techniques, popularized in the field of Quantum Information. Inspired by Nuclear Magnetic Resonance (NMR) spectroscopy, dynamical decoupling methods apply sequences of unitary operations to modify the interference phenomena responsible for the system dynamics thus also belonging to the general class of coherent control techniques. Here we review related developments in the fields of coherent optical control and dynamical decoupling, with emphasis on control of tunneling and decoherence in general model systems. Considering recent experimental breakthroughs in the demonstration of active control of a variety of systems, we anticipate that the reviewed coherent control scenarios and dynamical decoupling methods should raise significant experimental interest.
Pota, Himanshu Roy
564 IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 4, OCTOBER 2012 Dynamic Stability of Three-Phase Grid-Connected Photovoltaic System Using Zero Dynamic Design Approach M. A. Mahmud, Student Member of the dynamic response of a three-phase grid-connected photovoltaic (PV) system. To control the grid cur- rent
Amplitude and phase dynamics in oscillators with distributed-delay coupling
Y. N. Kyrychko; K. B. Blyuss; E. Schoell
2012-09-01T23:59:59.000Z
This paper studies the effects of distributed delay coupling on the dynamics in a system of non-identical coupled Stuart-Landau oscillators. For uniform and gamma delay distribution kernels, conditions for amplitude death are obtained in terms of average frequency, frequency detuning and parameters of the coupling, including coupling strength and phase, as well as the mean time delay and the width of the delay distribution. To gain further insight into the dynamics inside amplitude death regions, eigenvalues of the corresponding characteristic equations are computed numerically. Oscillatory dynamics of the system is also investigated using amplitude and phase representation. Various branches of phase-locked solutions are identified, and their stability is analysed for different types of delay distributions.
Nonlinear dynamics of phase separation in thin films
Lennon O Naraigh; Jean-Luc Thiffeault
2009-11-03T23:59:59.000Z
We present a long-wavelength approximation to the Navier-Stokes Cahn-Hilliard equations to describe phase separation in thin films. The equations we derive underscore the coupled behaviour of free-surface variations and phase separation. We introduce a repulsive substrate-film interaction potential and analyse the resulting fourth-order equations by constructing a Lyapunov functional, which, combined with the regularizing repulsive potential, gives rise to a positive lower bound for the free-surface height. The value of this lower bound depends on the parameters of the problem, a result which we compare with numerical simulations. While the theoretical lower bound is an obstacle to the rupture of a film that initially is everywhere of finite height, it is not sufficiently sharp to represent accurately the parametric dependence of the observed dips or `valleys' in free-surface height. We observe these valleys across zones where the concentration of the binary mixture changes sharply, indicating the formation of bubbles. Finally, we carry out numerical simulations without the repulsive interaction, and find that the film ruptures in finite time, while the gradient of the Cahn--Hilliard concentration develops a singularity.
Dynamics of skyrmions in chiral magnets: Dynamic phase transitions and equation of motion
Lin, Shi-Zeng, E-mail: szl@lanl.gov; Reichhardt, Charles; Batista, Cristian D.; Saxena, Avadh [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2014-05-07T23:59:59.000Z
We study the dynamics of skyrmions in a metallic chiral magnet. First, we show that skyrmions can be created dynamically by destabilizing the ferromagnetic background state through a spin polarized current. We then treat skyrmions as rigid particles and derive the corresponding equation of motion. The dynamics of skyrmions is dominated by the Magnus force, which accounts for the weak pinning of skyrmions observed in experiments. Finally, we discuss the quantum motion of skyrmions.
Chiral dynamics in the low-temperature phase of QCD
Bastian B. Brandt; Anthony Francis; Harvey B. Meyer; Daniel Robaina
2014-10-22T23:59:59.000Z
We investigate the low-temperature phase of QCD and the crossover region with two light flavors of quarks. The chiral expansion around the point $(T, m_q = 0)$ in the temperature vs. quark-mass plane indicates that a sharp real-time excitation exists with the quantum numbers of the pion. We determine its dispersion relation and test the applicability of the chiral expansion. The time-dependent correlators are also analyzed using the Maximum Entropy Method (MEM), yielding consistent results. Finally, we test the predictions of ordinary chiral perturbation theory around the point $(T = 0, m_q = 0)$ for the temperature dependence of static observables. Around the crossover temperature, we find that all quantities considered depend only mildly on the quark mass in the considered range 8MeV $\\leq \\bar{m}^{\\bar{\\text{MS}}} \\leq$ 15MeV.
Chiral dynamics in the low-temperature phase of QCD
Bastian B. Brandt; Anthony Francis; Harvey B. Meyer; Daniel Robaina
2014-06-21T23:59:59.000Z
We investigate the low-temperature phase of QCD and the crossover region with two light flavors of quarks. The chiral expansion around the point $(T,m=0)$ in the temperature vs. quark-mass plane indicates that a sharp real-time excitation exists with the quantum numbers of the pion. An exact sum rule is derived for the thermal modification of the spectral function associated with the axial charge density; the (dominant) pion pole contribution obeys the sum rule. We determine the two parameters of the pion dispersion relation using lattice QCD simulations and test the applicability of the chiral expansion. The time-dependent correlators are also analyzed using the Maximum Entropy Method, yielding consistent results. Finally, we test the predictions of the chiral expansion around the point $(T=0,m=0)$ for the temperature dependence of static observables.
Unique determination of the -CN group tilt angle in Langmuir...
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angle and phase. Abstract: The relative phase and amplitude ratio between the ssp and ppp polarization combinations of the vibrational sum-frequency generation (SFG) response...
Nanoscopic Dynamics of Phospholipid in Unilamellar Vesicles: Effect of Gel to Fluid Phase Transition
Sharma, Veerendra K [ORNL; Mamontov, Eugene [ORNL; Anunciado, Divina B [ORNL; O'Neill, Hugh Michael [ORNL; Urban, Volker S [ORNL
2015-01-01T23:59:59.000Z
Dynamics of phospholipids in unilamellar vesicles (ULV) is of interest in biology, medical, and food sciences since these molecules are widely used as biocompatible agents and a mimic of cell membrane systems. We have investigated the nanoscopic dynamics of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) phospholipid in ULV as a function of temperature using elastic and quasielastic neutron scattering (QENS). The dependence of the signal on the scattering momentum transfer, which is a critical advantage of neutron scattering techniques, allows the detailed analysis of the lipid motions that cannot be carried out by other means. In agreement with a differential scanning calorimetry measurement, a sharp rise in the elastic scattering intensity below ca. 296 K indicates a phase transition from the high-temperature fluid phase to the low-temperature solid gel phase. The microscopic lipid dynamics exhibits qualitative differences between the solid gel phase (in a measurement at 280 K) and the fluid phase (in a measurement at a physiological temperature of 310 K). The data analysis invariably shows the presence of two distinct motions: the whole lipid molecule motion within a monolayer, or lateral diffusion, and the relatively faster internal motion of the DMPC molecule. The lateral diffusion of the whole lipid molecule is found to be Fickian in character, whereas the internal lipid motions are of localized character, consistent with the structure of the vesicles. The lateral motion slows down by an order of magnitude in the solid gel phase, whereas for the internal motion not only the time scale, but also the character of the motion changes upon the phase transition. In the solid gel phase, the lipids are more ordered and undergo uniaxial rotational motion. However, in the fluid phase, the hydrogen atoms of the lipid tails undergo confined translation diffusion rather than uniaxial rotational diffusion. The localized translational diffusion of the hydrogen atoms of the lipid tails is a manifestation of the flexibility of the chains acquired in the fluid phase. Because of this flexibility, both the local diffusivity and the confinement volume for the hydrogen atoms increase linearly from near the lipid s polar head group to the end of its hydrophobic tail. Our results present a quantitative and detailed picture of the effect of the gel-fluid phase transition on the nanoscopic lipid dynamics in ULV. The data analysis approach developed here has a potential for probing the dynamic response of lipids to the presence of additional cell membrane components.
Contact angles in the pseudopotential lattice Boltzmann modeling of wetting
Q. Li; K. H. Luo; Q. J. Kang; Q. Chen
2014-10-21T23:59:59.000Z
In this paper, we aim to investigate the implementation of contact angles in the pseudopotential lattice Boltzmann modeling of wetting at a large density ratio. The pseudopotential lattice Boltzmann model [X. Shan and H. Chen, Phys. Rev. E 49, 2941 (1994)] is a popular mesoscopic model for simulating multiphase flows and interfacial dynamics. In this model, the contact angle is usually realized by a fluid-solid interaction. Two widely used fluid-solid interactions: the density-based interaction and the pseudopotential-based interaction, as well as a modified pseudopotential-based interaction formulated in the present paper, are numerically investigated and compared in terms of the achievable contact angles, the maximum and the minimum densities, and the spurious currents. It is found that the pseudopotential-based interaction works well for simulating small static (liquid) contact angles, however, is unable to reproduce static contact angles close to 180 degrees. Meanwhile, it is found that the proposed modified pseudopotential-based interaction performs better in light of the maximum and the minimum densities and is overall more suitable for simulating large contact angles as compared with the other two types of fluid-solid interactions. Furthermore, the spurious currents are found to be enlarged when the fluid-solid interaction force is introduced. Increasing the kinematic viscosity ratio between the vapor and liquid phases is shown to be capable of reducing the spurious currents caused by the fluid-solid interactions.
DYNAMIC MODELING STRATEGY FOR FLOW REGIME TRANSITION IN GAS-LIQUID TWO-PHASE FLOWS
X. Wang; X. Sun; H. Zhao
2011-09-01T23:59:59.000Z
In modeling gas-liquid two-phase flows, the concept of flow regime has been used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are often flow regime dependent. Currently, the determination of the flow regimes is primarily based on flow regime maps or transition criteria, which are developed for steady-state, fully-developed flows and widely applied in nuclear reactor system safety analysis codes, such as RELAP5. As two-phase flows are observed to be dynamic in nature (fully-developed two-phase flows generally do not exist in real applications), it is of importance to model the flow regime transition dynamically for more accurate predictions of two-phase flows. The present work aims to develop a dynamic modeling strategy for determining flow regimes in gas-liquid two-phase flows through the introduction of interfacial area transport equations (IATEs) within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation and destruction of the interfacial area, such as the fluid particle (bubble or liquid droplet) disintegration, boiling and evaporation; and fluid particle coalescence and condensation, respectively. For the flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shape (which are correlated), namely small bubbles and large bubbles. A preliminary approach to dynamically identifying the flow regimes is provided, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration of small bubble and large bubble groups. This method is expected to be applied to computer codes to improve their predictive capabilities of gas-liquid two-phase flows, in particular for the applications in which flow regime transition occurs.
Validation of DWPF MOG dynamics model -- Phase 1
Choi, A.S.
1996-09-23T23:59:59.000Z
The report documents the results of a study to validate the DWPF melter off-gas system dynamics model using the data collected during the Waste Qualification Runs in 1995. The study consisted of: (1) calibration of the model using one set of melter idling data, (2) validation of the calibrated model using three sets of steady feeding and one set of transient data, and (3) application of the validated model to simulate the melter overfeeding incident which took place on 7/5.95. All the controller tuning constants and control logic used in the validated model are identical to those used in the DCS in 1995. However, the model does not reflect any design and/or operational changes made in 1996 to alleviate the glass pouring problem. Based on the results of the overfeeding simulation, it is concluded that the actual feed rates during that incident were about 2.75 times the indicated readings and that the peak concentration of combustible gases remained below 15% of the lower flammable limit during the entire one-hour duration.
Ordering dynamics of blue phases entails kinetic stabilization of amorphous networks
O. Henrich; K. Stratford; D. Marenduzzo; M. E. Cates
2010-08-23T23:59:59.000Z
The cubic blue phases of liquid crystals are fascinating and technologically promising examples of hierarchically structured soft materials, comprising ordered networks of defect lines (disclinations) within a liquid crystalline matrix. We present the first large-scale simulations of their domain growth, starting from a blue phase nucleus within a supercooled isotropic or cholesteric background. The nucleated phase is thermodynamically stable; one expects its slow orderly growth, creating a bulk cubic. Instead, we find that the strong propensity to form disclinations drives the rapid disorderly growth of a metastable amorphous defect network. During this process the original nucleus is destroyed; re-emergence of the stable phase may therefore require a second nucleation step. Our findings suggest that blue phases exhibit hierarchical behavior in their ordering dynamics, to match that in their structure.
Phase synchronization and chaotic dynamics in Hebbian learned artificial recurrent neural networks
Molter, Colin
Phase synchronization and chaotic dynamics in Hebbian learned artificial recurrent neural networks: increasing the storing capacity of recurrent neural networks as much as possible and observing and studying Colin Molter, Utku Salihoglu and Hugues Bersini Laboratory of artificial intelligence IRIDIA cp194
Dinner, Aaron
2011-01-01T23:59:59.000Z
PHYSICAL REVIEW E 84, 061134 (2011) Entrainment of a driven oscillator as a dynamical phase, such as the glass transition. Here we use this approach to show that the entrainment of an oscillator to an external of eigenvalues for the unforced system. We find that in the entrainment region where the oscillator exhibits
Carrier-envelope phase dynamics of octave-spanning titanium:sapphire lasers
Sander, Michelle Yen-Ling
The carrier-envelope phase dynamics of octave-spanning Ti:sapphire lasers are analyzed based on a one-dimensional laser. It is found that self-steepening is the major contributor to the energy dependent carrier-envelope ...
Averaged dynamics of two-phase media in a vibration field Arthur V. Straubea
Straube, Arthur V.
to astronomic scales. Vibration is a mechanical oscillatory process with an amplitude that is small compared of the system is much larger than the period of the oscillation. Vibration mechanics has been studied for a longAveraged dynamics of two-phase media in a vibration field Arthur V. Straubea Department of Physics
J. M. Robbins
2010-09-10T23:59:59.000Z
Quantum eigenstates undergoing cyclic changes acquire a phase factor of geometric origin. This phase, known as the Berry phase, or the geometric phase, has found applications in a wide range of disciplines throughout physics, including atomic and molecular physics, condensed matter physics, optics, and classical dynamics. In this article, the basic theory of the geometric phase is presented along with a number of representative applications. The article begins with an account of the geometric phase for cyclic adiabatic evolutions. An elementary derivation is given along with a worked example for two-state systems. The implications of time-reversal are explained, as is the fundamental connection between the geometric phase and energy level degeneracies. We also discuss methods of experimental observation. A brief account is given of geometric magnetism; this is a Lorenz-like force of geometric origin which appears in the dynamics of slow systems coupled to fast ones. A number of theoretical developments of the geometric phase are presented. These include an informal discussion of fibre bundles, and generalizations of the geometric phase to degenerate eigenstates (the nonabelian case) and to nonadiabatic evolution. There follows an account of applications. Manifestations in classical physics include the Hannay angle and kinematic geometric phases. Applications in optics concern polarization dynamics, including the theory and observation of Pancharatnam's phase. Applications in molecular physics include the molecular Aharonov-Bohm effect and nuclear magnetic resonance studies. In condensed matter physics, we discuss the role of the geometric phase in the theory of the quantum Hall effect.
Flovik, Vegard; Hansen, Alex
2015-01-01T23:59:59.000Z
The change in contact angles due to the injection of low salinity water or any other wettability altering agent in an oil-rich porous medium is modeled by a network model of disordered pores transporting two immiscible fluids. We introduce a dynamic wettability altering mechanism, where the time dependent wetting property of each pore is determined by the cumulative flow of water through it. Simulations are performed to reach steady-state for different possible alterations in the wetting angle ($\\theta$). We find that deviation from oil-wet conditions re-mobilizes the stuck clusters and increases the oil fractional flow. However, the rate of increase in the fractional flow depends strongly on $\\theta$ and as $\\theta\\to 90^\\circ$, a critical angle, the system shows critical slowing down which is characterized by two dynamic critical exponents.
Shchekinova, E.; Uzer, T. [Center for Nonlinear Science, School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States); Chandre, C. [Centre de Physique Theorique-CNRS, Luminy, Case 907, 13288 Marseille Cedex 09 (France)
2006-10-15T23:59:59.000Z
The multiphoton ionization of hydrogen atoms in a strong elliptically polarized microwave field exhibits complex features that are not observed for ionization in circular and linear polarized fields. Experimental data reveal high sensitivity of ionization dynamics to the small changes of the field polarization. The multidimensional nature of the problem makes widely used diagnostics of dynamics, such as Poincare surfaces of section, impractical. We analyze the phase-space dynamics using the finite time stability analysis rendered by the fast Lyapunov indicators technique. The concept of zero-velocity surface is used to initialize the calculations and visualize the dynamics. Our analysis provides stability maps calculated for the initial energy at the maximum and below the saddle of the zero-velocity surface. We estimate qualitatively the dependence of ionization thresholds on the parameters of the applied field, such as polarization and scaled amplitude.
Integrability and nonintegrability of quantum systems. II. Dynamics in quantum phase space
Zhang, Weimin (Department of Physics, FM-15, University of Washington, Seattle, WA (USA) Department of Physics and Atmospheric Science, Drexel University, Philadelphia, PA (USA)); Feng, D.H.; Yuan, Jianmin (Department of Physics and Atmospheric Science, Drexel University, Philadelphia, PA (USA))
1990-12-15T23:59:59.000Z
Based on the concepts of integrability and nonintegrability of a quantum system presented in a previous paper (Zhang, Feng, Yuan, and Wang, Phys. Rev. A 40, 438 (1989)), a realization of the dynamics in the quantum phase space is now presented. For a quantum system with dynamical group {ital G-script} and in one of its unitary irreducible-representation carrier spaces {ital h-german}{sub {Lambda}}, the quantum phase space is a 2{ital M}{sub {Lambda}}-dimensional topological space, where {ital M}{sub {Lambda}} is the quantum-dynamical degrees of freedom. This quantum phase space is isomorphic to a coset space {ital G-script}/{ital H-script} via the unitary exponential mapping of the elementary excitation operator subspace of {ital g-script} (algebra of {ital G-script}), where {ital H-script} ({contained in}{ital G-script}) is the maximal stability subgroup of a fixed state in {ital h-german}{sub {Lambda}}. The phase-space representation of the system is realized on {ital G-script}/{ital H-script}, and its classical analogy can be obtained naturally. It is also shown that there is consistency between quantum and classical integrability. Finally, a general algorithm for seeking the manifestation of quantum chaos'' via the classical analogy is provided. Illustrations of this formulation in several important quantum systems are presented.
Relaxation dynamics in a transient network fluid with competing gel and glass phases
Pinaki Chaudhuri; Pablo I. Hurtado; Ludovic Berthier; Walter Kob
2015-02-01T23:59:59.000Z
We use computer simulations to study the relaxation dynamics of a model for oil-in-water microemulsion droplets linked with telechelic polymers. This system exhibits both gel and glass phases and we show that the competition between these two arrest mechanisms can result in a complex, three-step decay of the time correlation functions, controlled by two different localization lengthscales. For certain combinations of the parameters, this competition gives rise to an anomalous logarithmic decay of the correlation functions and a subdiffusive particle motion, which can be understood as a simple crossover effect between the two relaxation processes. We establish a simple criterion for this logarithmic decay to be observed. We also find a further logarithmically slow relaxation related to the relaxation of floppy clusters of particles in a crowded environment, in agreement with recent findings in other models for dense chemical gels. Finally, we characterize how the competition of gel and glass arrest mechanisms affects the dynamical heterogeneities and show that for certain combination of parameters these heterogeneities can be unusually large. By measuring the four-point dynamical susceptibility, we probe the cooperativity of the motion and find that with increasing coupling this cooperativity shows a maximum before it decreases again, indicating the change in the nature of the relaxation dynamics. Our results suggest that compressing gels to large densities produces novel arrested phases that have a new and complex dynamics.
On the dynamics of traveling phase-oscillators with positive and negative couplings
J. Choi; M. Y. Choi; B. -G. Yoon
2014-10-10T23:59:59.000Z
We investigate numerically the dynamics of traveling clusters in systems of phase oscillators, some of which possess positive couplings and others negative couplings. The phase distribution, speed of traveling, and average separation between clusters as well as order parameters for positive and negative oscillators are computed, as the ratio of the two coupling constants and/or the fraction of positive oscillators are varied. The traveling speed depending on these parameters is obtained and observed to fit well with the numerical data of the systems. With the help of this, we describe the conditions for the traveling state to appear in the systems with or without periodic driving.
Asymptotic Entanglement Dynamics Phase Diagrams for Two Electromagnetic Field Modes in a Cavity
R. C. Drumond; L. A. M. Souza; M. Terra Cunha
2010-10-20T23:59:59.000Z
We investigate theoretically an open dynamics for two modes of electromagnetic field inside a microwave cavity. The dynamics is Markovian and determined by two types of reservoirs: the "natural" reservoirs due to dissipation and temperature of the cavity, and an engineered one, provided by a stream of atoms passing trough the cavity, as devised in [Pielawa \\emph{et al.} \\emph{Phys. Rev. Lett.} \\textbf{98}, 240401 (2007)]. We found that, depending on the reservoir parameters, the system can have distinct "phases" for the asymptotic entanglement dynamics: it can disentangle at finite time or it can have persistent entanglement for large times, with the transition between them characterized by the possibility of asymptotical disentanglement. Incidentally, we also discuss the effects of dissipation on the scheme proposed in the above reference for generation of entangled states.
Dynamic migration of rotating neutron stars due to a phase transition instability
Harald Dimmelmeier; Michal Bejger; Pawel Haensel; J. Leszek Zdunik
2009-04-09T23:59:59.000Z
Using numerical simulations based on solving the general relativistic hydrodynamic equations, we study the dynamics of a phase transition in the dense core of isolated rotating neutron stars, triggered by the back bending instability reached via angular momentum loss. In particular, we investigate the dynamics of a migration from an unstable configuration into a stable one, which leads to a mini-collapse of the neutron star and excites sizeable pulsations in its bulk until it acquires a new stable equilibrium state. We consider equations of state with softening at high densities, a simple analytic one with a mixed hadron-quark phase in an intermediate pressure interval and pure quark matter at very high densities, and a microphysical one that has a first-order phase transition, originating from kaon condensation. Although the marginally stable initial models are rigidly rotating, we observe that during the collapse (albeit little) differential rotation is created. We analyze the emission of gravitational radiation, which in some models is amplified by mode resonance effects, and assess its prospective detectability by interferometric detectors. We expect that the most favorable conditions for dynamic migration exist in very young magnetars. We find that the damping of the post-migration pulsations strongly depends on the character of the equation of state softening. The damping of pulsations in the models with the microphysical equation of state is caused by dissipation associated with matter flowing through the density jump at the edge of the dense core. If at work, this mechanism dominates over all other types of dissipation, like bulk viscosity in the exotic-phase core, gravitational radiation damping, or numerical viscosity.
Liu, Yun, 1973-
2005-01-01T23:59:59.000Z
This thesis is organized into two parts which focus on the studies of the dynamic structure factor and static inter-particle structure factor respectively. In the first part, we have measured and analyzed the dynamic ...
Apkarian, V. Ara
Interrogation and control of condensed phase chemical dynamics with linearly chirped pulses: I2, Irvine, California 92717 Received 19 October 1995; accepted 30 January 1996 The effect of linearly pulse chirp, is a measure of the controllability of the evolving dynamics. In the particular case
Demler, Eugene
2015-01-01T23:59:59.000Z
changes. We discuss the characterization of such dynamical phase transitions based on the statistics is a subject of interest in many areas of physics involving cold- atomic gases [1], solid-state pump and probe and discuss a characterization of dynamical critical phenomena in bosonic systems based on the full statistics
Cerveny, Vlastislav
2006-01-01T23:59:59.000Z
Physics of the Earth and Planetary Interiors 154 (2006) 196207 Lower mantle dynamics with the post-perovskite; accepted 9 October 2005 Abstract The new post-perovskite phase near the coremantle boundary has important change at 670 km depth and an exothermic post-perovskite transition at 2650 km depth. The phase
Bhatti, Kanwal Preet; El-Khatib, S.; Srivastava, Vijay; James, R. D.; Leighton, C.
2012-04-01T23:59:59.000Z
The Heusler-derived multiferroic alloy Ni_{50–x}Co_{x}Mn??Sn?? has recently been shown to exhibit, at just above room temperature, a highly reversible martensitic phase transformation with an unusually large magnetization change. In this work the nature of the magnetic ordering above and below this transformation has been studied in detail in the critical composition range x = 6–8 via temperature-dependent (5–600 K) magnetometry and small-angle neutron scattering (SANS). We observe fairly typical paramagnetic to long-range-ordered ferromagnetic phase transitions on cooling to 420–430 K, with the expected critical spin fluctuations, followed by first-order martensitic phase transformations to a nonferromagnetic state below 360–390 K. The static magnetization reveals complex magnetism in this low-temperature nonferromagnetic phase, including a Langevin-like field dependence, distinct spin freezing near 60 K, and significant exchange bias effects, consistent with superparamagnetic blocking of ferromagnetic clusters of nanoscopic dimensions. We demonstrate that these spin clusters, whose existence has been hypothesized in a variety of martensitic alloys exhibiting competition between ferromagnetic and antiferromagnetic exchange interactions, can be directly observed by SANS. The scattering data are consistent with a liquidlike spatial distribution of interacting magnetic clusters with a mean center-to-center spacing of 12 nm. Considering the behavior of the superparmagnetism, cooling-field and temperature-dependent exchange bias, and magnetic SANS, we discuss in detail the physical form and origin of these spin clusters, their intercluster interactions, the nature of the ground-state magnetic ordering in the martensitic phase, and the implications for our understanding of such alloy systems.
F. A. L. Mauguière; P. Collins; G. S. Ezra; S. C. Farantos; S. Wiggins
2014-01-31T23:59:59.000Z
A model Hamiltonian for the reaction CH$_4^+ \\rightarrow$ CH$_3^+$ + H, parametrized to exhibit either early or late inner transition states, is employed to investigate the dynamical characteristics of the roaming mechanism. Tight/loose transition states and conventional/roaming reaction pathways are identified in terms of time-invariant objects in phase space. These are dividing surfaces associated with normally hyperbolic invariant manifolds (NHIMs). For systems with two degrees of freedom NHIMS are unstable periodic orbits which, in conjunction with their stable and unstable manifolds, unambiguously define the (locally) non-recrossing dividing surfaces assumed in statistical theories of reaction rates. By constructing periodic orbit continuation/bifurcation diagrams for two values of the potential function parameter corresponding to late and early transition states, respectively, and using the total energy as another parameter, we dynamically assign different regions of phase space to reactants and products as well as to conventional and roaming reaction pathways. The classical dynamics of the system are investigated by uniformly sampling trajectory initial conditions on the dividing surfaces. Trajectories are classified into four different categories: direct reactive and non reactive trajectories,which lead to the formation of molecular and radical products respectively, and roaming reactive and non reactive orbiting trajectories, which represent alternative pathways to form molecular and radical products. By analysing gap time distributions at several energies we demonstrate that the phase space structure of the roaming region, which is strongly influenced by non-linear resonances between the two degrees of freedom, results in nonexponential (nonstatistical) decay.
Dynamics in the quantum Hall effect and the phase diagram of graphene
E. V. Gorbar; V. P. Gusynin; V. A. Miransky; I. A. Shovkovy
2008-08-28T23:59:59.000Z
The dynamics responsible for lifting the degeneracy of the Landau levels in the quantum Hall (QH) effect in graphene is studied by utilizing a low-energy effective model with a contact interaction. A detailed analysis of the solutions of the gap equation for Dirac quasiparticles is performed at both zero and nonzero temperatures. The characteristic feature of the solutions is that the order parameters connected with the QH ferromagnetism and magnetic catalysis scenarios necessarily coexist. The solutions reproduce correctly the experimentally observed novel QH plateaus in graphene in strong magnetic fields. The phase diagram of this system in the plane of temperature and electron chemical potential is analyzed. The phase transitions corresponding to the transitions between different QH plateaus in graphene are described.
Liquid phase fluid dynamic (methanol) run in the LaPorte alternative fuels development unit
Bharat L. Bhatt
1997-05-01T23:59:59.000Z
A fluid dynamic study was successfully completed in a bubble column at DOE's Alternative Fuels Development Unit (AFDU) in LaPorte, Texas. Significant fluid dynamic information was gathered at pilot scale during three weeks of Liquid Phase Methanol (LPMEOJP) operations in June 1995. In addition to the usual nuclear density and temperature measurements, unique differential pressure data were collected using Sandia's high-speed data acquisition system to gain insight on flow regime characteristics and bubble size distribution. Statistical analysis of the fluctuations in the pressure data suggests that the column was being operated in the churn turbulent regime at most of the velocities considered. Dynamic gas disengagement experiments showed a different behavior than seen in low-pressure, cold-flow work. Operation with a superficial gas velocity of 1.2 ft/sec was achieved during this run, with stable fluid dynamics and catalyst performance. Improvements included for catalyst activation in the design of the Clean Coal III LPMEOH{trademark} plant at Kingsport, Tennessee, were also confirmed. In addition, an alternate catalyst was demonstrated for LPMEOH{trademark}.
Williams, Ronald H
1979-01-01T23:59:59.000Z
conditions, several static and dynamic 2, 3&4 methods have been used in lieu of di& ect injec*ion. These methods depend on dosing the adsorbent with a known amount of analyte from the vapor phase. They include (but are not limited to) the use of U ? tubes... results in a smaller proportion of the adsorbate striking 6 an unoccupied site and remaining on the surface. Also, active sites (discussed later in this papez') on the surface of the adsorbent retain the adsorbate more readily than other areas so...
Hou, Guangjin, E-mail: hou@udel.edu, E-mail: tpolenov@udel.edu; Lu, Xingyu, E-mail: luxingyu@udel.edu, E-mail: lexvega@comcast.net; Vega, Alexander J., E-mail: luxingyu@udel.edu, E-mail: lexvega@comcast.net; Polenova, Tatyana, E-mail: hou@udel.edu, E-mail: tpolenov@udel.edu [Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, Pennsylvania 15261 (United States)
2014-09-14T23:59:59.000Z
We report a Phase-Alternating R-Symmetry (PARS) dipolar recoupling scheme for accurate measurement of heteronuclear {sup 1}H-X (X = {sup 13}C, {sup 15}N, {sup 31}P, etc.) dipolar couplings in MAS NMR experiments. It is an improvement of conventional C- and R-symmetry type DIPSHIFT experiments where, in addition to the dipolar interaction, the {sup 1}H CSA interaction persists and thereby introduces considerable errors in the dipolar measurements. In PARS, phase-shifted RN symmetry pulse blocks applied on the {sup 1}H spins combined with ? pulses applied on the X spins at the end of each RN block efficiently suppress the effect from {sup 1}H chemical shift anisotropy, while keeping the {sup 1}H-X dipolar couplings intact. Another advantage over conventional DIPSHIFT experiments, which require the signal to be detected in the form of a reduced-intensity Hahn echo, is that the series of ? pulses refocuses the X chemical shift and avoids the necessity of echo formation. PARS permits determination of accurate dipolar couplings in a single experiment; it is suitable for a wide range of MAS conditions including both slow and fast MAS frequencies; and it assures dipolar truncation from the remote protons. The performance of PARS is tested on two model systems, [{sup 15}N]-N-acetyl-valine and [U-{sup 13}C,{sup 15}N]-N-formyl-Met-Leu-Phe tripeptide. The application of PARS for site-resolved measurement of accurate {sup 1}H-{sup 15}N dipolar couplings in the context of 3D experiments is presented on U-{sup 13}C,{sup 15}N-enriched dynein light chain protein LC8.
Computational Particle Dynamic Simulations on Multicore Processors (CPDMu) Final Report â?? Phase I
Mark S. Schmalz
2011-07-24T23:59:59.000Z
Statement of Problem - Department of Energy has many legacy codes for simulation of computational particle dynamics and computational fluid dynamics applications that are designed to run on sequential processors and are not easily parallelized. Emerging high-performance computing architectures employ massively parallel multicore architectures (e.g., graphics processing units) to increase throughput. Parallelization of legacy simulation codes is a high priority, to achieve compatibility, efficiency, accuracy, and extensibility. General Statement of Solution - A legacy simulation application designed for implementation on mainly-sequential processors has been represented as a graph G. Mathematical transformations, applied to G, produce a graph representation {und G} for a high-performance architecture. Key computational and data movement kernels of the application were analyzed/optimized for parallel execution using the mapping G {yields} {und G}, which can be performed semi-automatically. This approach is widely applicable to many types of high-performance computing systems, such as graphics processing units or clusters comprised of nodes that contain one or more such units. Phase I Accomplishments - Phase I research decomposed/profiled computational particle dynamics simulation code for rocket fuel combustion into low and high computational cost regions (respectively, mainly sequential and mainly parallel kernels), with analysis of space and time complexity. Using the research team's expertise in algorithm-to-architecture mappings, the high-cost kernels were transformed, parallelized, and implemented on Nvidia Fermi GPUs. Measured speedups (GPU with respect to single-core CPU) were approximately 20-32X for realistic model parameters, without final optimization. Error analysis showed no loss of computational accuracy. Commercial Applications and Other Benefits - The proposed research will constitute a breakthrough in solution of problems related to efficient parallel computation of particle and fluid dynamics simulations. These problems occur throughout DOE, military and commercial sectors: the potential payoff is high. We plan to license or sell the solution to contractors for military and domestic applications such as disaster simulation (aerodynamic and hydrodynamic), Government agencies (hydrological and environmental simulations), and medical applications (e.g., in tomographic image reconstruction). Keywords - High-performance Computing, Graphic Processing Unit, Fluid/Particle Simulation. Summary for Members of Congress - Department of Energy has many simulation codes that must compute faster, to be effective. The Phase I research parallelized particle/fluid simulations for rocket combustion, for high-performance computing systems.
Hahn, Steven
2012-07-20T23:59:59.000Z
Modern calculations are becoming an essential, complementary tool to inelastic x-ray scattering studies, where x-rays are scattered inelastically to resolve meV phonons. Calculations of the inelastic structure factor for any value of Q assist in both planning the experiment and analyzing the results. Moreover, differences between the measured data and theoretical calculations help identify important new physics driving the properties of novel correlated systems. We have used such calculations to better and more e#14;ciently measure the phonon dispersion and elastic constants of several iron pnictide superconductors. This dissertation describes calculations and measurements at room temperature in the tetragonal phase of CaFe{sub 2}As{sub 2} and LaFeAsO. In both cases, spin-polarized calculations imposing the antiferromagnetic order present in the low-temperature orthorhombic phase dramatically improves the agreement between theory and experiment. This is discussed in terms of the strong antiferromagnetic correlations that are known to persist in the tetragonal phase. In addition, we discuss a relatively new approach called self-consistent ab initio lattice dynamics (SCAILD), which goes beyond the harmonic approximation to include phonon-phonon interactions and produce a temperature-dependent phonon dispersion. We used this technique to study the HCP to BCC transition in beryllium.
Tobias Rindlisbacher; Philippe de Forcrand
2015-03-12T23:59:59.000Z
The transition between the two phases of 4D Euclidean Dynamical Triangulation [1] was long believed to be of second order until in 1996 first order behavior was found for sufficiently large systems [5,9]. However, one may wonder if this finding was affected by the numerical methods used: to control volume fluctuations, in both studies [5,9] an artificial harmonic potential was added to the action; in [9] measurements were taken after a fixed number of accepted instead of attempted moves which introduces an additional error. Finally the simulations suffer from strong critical slowing down which may have been underestimated. In the present work, we address the above weaknesses: we allow the volume to fluctuate freely within a fixed interval; we take measurements after a fixed number of attempted moves; and we overcome critical slowing down by using an optimized parallel tempering algorithm [12]. With these improved methods, on systems of size up to 64k 4-simplices, we confirm that the phase transition is first order. In addition, we discuss a local criterion to decide whether parts of a triangulation are in the elongated or crumpled state and describe a new correspondence between EDT and the balls in boxes model. The latter gives rise to a modified partition function with an additional, third coupling. Finally, we propose and motivate a class of modified path-integral measures that might remove the metastability of the Markov chain and turn the phase transition into second order.
Tobias Rindlisbacher; Philippe de Forcrand
2015-06-10T23:59:59.000Z
The transition between the two phases of 4D Euclidean Dynamical Triangulation [1] was long believed to be of second order until in 1996 first order behavior was found for sufficiently large systems [5,9]. However, one may wonder if this finding was affected by the numerical methods used: to control volume fluctuations, in both studies [5,9] an artificial harmonic potential was added to the action; in [9] measurements were taken after a fixed number of accepted instead of attempted moves which introduces an additional error. Finally the simulations suffer from strong critical slowing down which may have been underestimated. In the present work, we address the above weaknesses: we allow the volume to fluctuate freely within a fixed interval; we take measurements after a fixed number of attempted moves; and we overcome critical slowing down by using an optimized parallel tempering algorithm [12]. With these improved methods, on systems of size up to 64k 4-simplices, we confirm that the phase transition is first order. In addition, we discuss a local criterion to decide whether parts of a triangulation are in the elongated or crumpled state and describe a new correspondence between EDT and the balls in boxes model. The latter gives rise to a modified partition function with an additional, third coupling. Finally, we propose and motivate a class of modified path-integral measures that might remove the metastability of the Markov chain and turn the phase transition into second order.
Thomas Speck; Andreas M. Menzel; Julian Bialké; Hartmut Löwen
2015-03-29T23:59:59.000Z
Recently, we have derived an effective Cahn-Hilliard equation for the phase separation dynamics of active Brownian particles by performing a weakly non-linear analysis of the effective hydrodynamic equations for density and polarization [Phys. Rev. Lett. 112, 218304 (2014)]. Here we develop and explore this strategy in more detail and show explicitly how to get to such a large-scale, mean-field description starting from the microscopic dynamics. The effective free energy emerging from this approach has the form of a conventional Ginzburg-Landau function. On the coarsest scale, our results thus agree with the mapping of active phase separation onto that of passive fluids with attractive interactions through a global effective free energy (mobility-induced phase transition). Particular attention is paid to the square-gradient term necessary for the dynamics. We finally discuss results from numerical simulations corroborating the analytical results.
Measuring the dynamic structure factor of a quantum gas undergoing a structural phase transition
Renate Landig; Ferdinand Brennecke; Rafael Mottl; Tobias Donner; Tilman Esslinger
2015-03-18T23:59:59.000Z
The dynamic structure factor is a central quantity describing the physics of quantum many-body systems, capturing structure and collective excitations of a material. In condensed matter, it can be measured via inelastic neutron scattering, which is an energy-resolving probe for the density fluctuations. In ultracold atoms, a similar approach could so far not be applied due to the diluteness of the system. Here, we report on a direct, real-time and non-destructive measurement of the dynamic structure factor of a quantum gas exhibiting cavity-mediated long-range interactions. The technique relies on inelastic scattering of photons, stimulated by the enhanced vacuum field inside a high finesse optical cavity. We extract the density fluctuations, their energy and lifetime while the system undergoes a structural phase transition. We observe an occupation of the relevant quasi-particle mode on the level of a few excitations, and provide a theoretical description of this dissipative quantum many-body system.
Rindlisbacher, Tobias
2015-01-01T23:59:59.000Z
The transition between the two phases of 4D Euclidean Dynamical Triangulation [1] was long believed to be of second order until in 1996 first order behavior was found for sufficiently large systems [5,9]. However, one may wonder if this finding was affected by the numerical methods used: to control volume fluctuations, in both studies [5,9] an artificial harmonic potential was added to the action; in [9] measurements were taken after a fixed number of accepted instead of attempted moves which introduces an additional error. Finally the simulations suffer from strong critical slowing down which may have been underestimated. In the present work, we address the above weaknesses: we allow the volume to fluctuate freely within a fixed interval; we take measurements after a fixed number of attempted moves; and we overcome critical slowing down by using an optimized parallel tempering algorithm [12]. With these improved methods, on systems of size up to 64k 4-simplices, we confirm that the phase transition is first ...
Zaveri, Rahul A.; Easter, Richard C.; Shilling, John E.; Seinfeld, J. H.
2014-05-27T23:59:59.000Z
Evidence is mounting that the majority of the climatically active aerosols are produced through the growth of smaller particles via secondary organic aerosol (SOA) formation from gas-to-particle conversion of anthropogenic and biogenic volatile organic compounds (VOCs). The timescale of SOA partitioning and the associated size distribution dynamics are expected to depend on the gas-phase oxidation of the precursor VOCs and their products, volatility of these organic solutes, composition and phase state of the pre-existing particles, and diffusivity and reactivity of the solute within the particle phase. This paper describes a new framework for modeling kinetic gas-particle partitioning of SOA, with an analytical treatment for the diffusion-reaction process within the particle phase. The formulation is amenable for eventual use in regional and global climate models, although it currently awaits implementation of the actual particle-phase reactions that are important for SOA formation. In the present work, the model is applied to investigate the competitive growth dynamics of the Aitken and accumulation mode particles while the Kelvin effect and coagulation are neglected for simplicity. The timescale of SOA partitioning and evolution of number and composition size distributions are evaluated for a range of solute volatilities (C*), particle-phase bulk diffusivities (Db), and particle-phase reactivity, as exemplified by a pseudo-first-order rate constant (kc). Results show that irreversible condensation of non-volatile organic vapors (equivalent to ) produces significant narrowing of the size distribution. At the other extreme, non-reactive partitioning of semi-volatile organic vapors is volume-controlled in which the final (equilibrium) size distribution simply shifts to the right on the diameter axis while its shape remains unchanged. However, appreciable narrowing of the size distribution may occur when the pre-existing particles are highly viscous semi-solids such that small particles reach quasi-equilibrium much faster than the large ones. In the case of reactive partitioning (finite ), the size distribution experiences permanent narrowing, which is especially pronounced for Db < 10-13 cm2 s-1 and kc > 0.01 s-1. As a result, both number and composition size distributions are needed to effectively constrain and evaluate the next generation of SOA models that treat phase state thermodynamics, particle-phase diffusion and particle-phase chemical reactions.
Stanley, H. Eugene
2014-01-01T23:59:59.000Z
PHYSICAL REVIEW E 89, 042807 (2014) Network risk and forecasting power in phase-flipping dynamical China University of Science and Technology, Shanghai 200237, China 8 Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People
56.th APS DPP Meeting, New Orleans BP8.00039 -1 Role of phase locking in nonlinear dynamics
Zonca, Fulvio
.S.A. October 27.th, 2014 New Orleans Marriott Hotel 56th Annual Meeting of the APS Division of Plasma Physics56.th APS DPP Meeting, New Orleans BP8.00039 - 1 Role of phase locking in nonlinear dynamics - Frascati, Italy 2 Institute for Fusion Theory and Simulation and Dept. of Physics, Zhejiang University
Can xenon in water inhibit ice growth? Molecular dynamics of phase transitions in water$-$Xe system
Vasilii I. Artyukhov; Alexander Yu. Pulver; Alex Peregudov; Igor Artyuhov
2014-07-11T23:59:59.000Z
Motivated by recent experiments showing the promise of noble gases as cryoprotectants, we perform molecular dynamics modeling of phase transitions in water with xenon under cooling. We study the structure and dynamics of xenon water solution as a function of temperature. Homogeneous nucleation of clathrate hydrate phase is observed and characterized. As the temperature is further reduced we observe hints of dissociation of clathrate due to stronger hydrophobic hydration, pointing towards a possible instability of clathrate at cryogenic temperatures and conversion to an amorphous phase comprised of "xenon + hydration shell" Xe$\\cdot$(H$_{2}$O)$_{21.5}$ clusters. Simulations of ice$-$xenon solution interface in equilibrium and during ice growth reveal the effects of xenon on the ice$-$liquid interface, where adsorbed xenon causes roughening of ice surface but does not preferentially form clathrate. These results provide evidence against the ice-blocker mechanism of xenon cryoprotection.
Sylwia Calus; Andriy V. Kityk; Manfred Eich; Patrick Huber
2015-04-19T23:59:59.000Z
We report filling-fraction dependent dielectric spectroscopy measurements on the relaxation dynamics of the rod-like nematogen 7CB condensed in 13 nm silica nanochannels. In the film-condensed regime, a slow interface relaxation dominates the dielectric spectra, whereas from the capillary-condensed state up to complete filling an additional, fast relaxation in the core of the channels is found. The temperature-dependence of the static capacitance, representative of the averaged, collective molecular orientational ordering, indicates a continuous, paranematic-to-nematic (P-N) transition, in contrast to the discontinuous bulk behaviour. It is well described by a Landau-de-Gennes free energy model for a phase transition in cylindrical confinement. The large tensile pressure of 10 MPa in the capillary-condensed state, resulting from the Young-Laplace pressure at highly curved liquid menisci, quantitatively accounts for a downward-shift of the P-N transition and an increased molecular mobility in comparison to the unstretched liquid state of the complete filling. The strengths of the slow and fast relaxations provide local information on the orientational order: The thermotropic behaviour in the core region is bulk-like, i.e. it is characterized by an abrupt onset of the nematic order at the P-N transition. By contrast, the interface ordering exhibits a continuous evolution at the P-N transition. Thus, the phase behaviour of the entirely filled liquid crystal-silica nanocomposite can be quantitatively described by a linear superposition of these distinct nematic order contributions.
Calus, Sylwia; Eich, Manfred; Huber, Patrick
2015-01-01T23:59:59.000Z
We report filling-fraction dependent dielectric spectroscopy measurements on the relaxation dynamics of the rod-like nematogen 7CB condensed in 13 nm silica nanochannels. In the film-condensed regime, a slow interface relaxation dominates the dielectric spectra, whereas from the capillary-condensed state up to complete filling an additional, fast relaxation in the core of the channels is found. The temperature-dependence of the static capacitance, representative of the averaged, collective molecular orientational ordering, indicates a continuous, paranematic-to-nematic (P-N) transition, in contrast to the discontinuous bulk behaviour. It is well described by a Landau-de-Gennes free energy model for a phase transition in cylindrical confinement. The large tensile pressure of 10 MPa in the capillary-condensed state, resulting from the Young-Laplace pressure at highly curved liquid menisci, quantitatively accounts for a downward-shift of the P-N transition and an increased molecular mobility in comparison to the...
Pretto, Dalyir I.; Tsutakawa, Susan; Brosey, Chris A.; Castillo, Amalchi; Chagot, Marie-Eve; Smith, Jarrod A.; Tainer, John A.; Chazin, Walter J.
2010-03-11T23:59:59.000Z
Replication Protein A (RPA) is the primary eukaryotic ssDNA binding protein utilized in diverse DNA transactions in the cell. RPA is a heterotrimeric protein with seven globular domains connected by flexible linkers, which enable substantial inter-domain motion that is essential to its function. Small angle X-ray scattering (SAXS) experiments on two multi-domain constructs from the N-terminus of the large subunit (RPA70) were used to examine the structural dynamics of these domains and their response to the binding of ssDNA. The SAXS data combined with molecular dynamics simulations reveal substantial interdomain flexibility for both RPA70AB (the tandem high affinity ssDNA binding domains A and B connected by a 10-residue linker) and RPA70NAB (RPA70AB extended by a 70-residue linker to the RPA70N protein interaction domain). Binding of ssDNA to RPA70NAB reduces the interdomain flexibility between the A and B domains, but has no effect on RPA70N. These studies provide the first direct measurements of changes in orientation of these three RPA domains upon binding ssDNA. The results support a model in which RPA70N remains structurally independent of RPA70AB in the DNA bound state and therefore freely available to serve as a protein recruitment module.
Paris-Sud XI, Université de
Dynamics of a three-phase upflow fixed bed catalytic reactor C. Julcour, F. Stüber, J. M. Le Lann, 31078 Toulouse Cedex, France * Corresponding author Abstract A dynamic model of an upflow fixed bed experimentally observed at very high hydrogen flow rates. Keywords: fixed bed reactor; cocurrent upflow; dynamic
Cohen, Oren (Boulder, CO); Kapteyn, Henry C. (Boulder, CO); Mumane, Margaret M. (Boulder, CO)
2010-02-16T23:59:59.000Z
Phase matching high harmonic generation (HHG) uses a single, long duration non-collinear modulating pulse intersecting the driving pulse. A femtosecond driving pulse is focused into an HHG medium (such as a noble gas) to cause high-harmonic generation (HHG), for example in the X-ray region of the spectrum, via electrons separating from and recombining with gas atoms. A non-collinear pulse intersects the driving pulse within the gas, and modulates the field seen by the electrons while separated from their atoms. The modulating pulse is low power and long duration, and its frequency and amplitude is chosen to improve HHG phase matching by increasing the areas of constructive interference between the driving pulse and the HHG, relative to the areas of destructive interference.
1 A study of localisation in dual phase high-strength steels under dynamic loading using digital conducted on dual-phase high-strength steel in a split-Hopkinson tension bar at a strain-rate in the range-speed photography, localisation, dual-phase high strength-steel, split- Hopkinson bar, photomechanics, elasto
Paris-Sud XI, Université de
1 A study of localisation in dual phase high-strength steels under dynamic loading using digital of an elasto-viscoplastic constitutive model for the dual-phase steel is provided in terms of its ability for the shell element analysis. Keywords: high-speed photography, localisation, dual-phase high strength-steel
Lattice Spacing Dependence of the First Order Phase Transition for Dynamical Twisted Mass Fermions
F. Farchioni; K. Jansen; I. Montvay; E. E. Scholz; L. Scorzato; A. Shindler; N. Ukita; C. Urbach; U. Wenger; I. Wetzorke
2005-06-28T23:59:59.000Z
Lattice QCD with Wilson fermions generically shows the phenomenon of a first order phase transition. We study the phase structure of lattice QCD using Wilson twisted mass fermions and the Wilson plaquette gauge action are used in a range of beta values where such a first order phase transition is observed. In particular, we investigate the dependence of the first order phase transition on the value of the lattice spacing. Using only data in one phase and neglecting possible problems arising from the phase transition we are able to perform a first scaling test for physical quantities using this action.
Suman Chakrabarty; Dwaipayan Chakrabarti; Biman Bagchi
2006-03-14T23:59:59.000Z
Orientational dynamics in a liquid crystalline system near the isotropic-nematic (I-N) phase transition is studied using Molecular Dynamics simulations of the well-known Lebwohl-Lasher (LL) model. As the I-N transition temperature is approached from the isotropic side, we find that the decay of the orientational time correlation functions (OTCF) slows down noticeably, giving rise to a power law decay at intermediate timescales. The angular velocity time correlation function also exhibits a rather pronounced power law decay near the I-N boundary. In the mean squared angular displacement at comparable timescales, we observe the emergence of a \\emph{subdiffusive regime} which is followed by a \\emph{superdiffusive regime} before the onset of the long-time diffusive behavior. We observe signature of dynamical heterogeneity through \\emph{pronounced non-Gaussian behavior in orientational motion} particularly at lower temperatures. This behavior closely resembles what is usually observed in supercooled liquids. We obtain the free energy as a function of orientational order parameter by the use of transition matrix Monte Carlo method. The free energy surface is flat for the system considered here and the barrier between isotropic and nematic phases is vanishingly small for this weakly first-order phase transition, hence allowing large scale, collective and correlated orientational density fluctuations. This might be responsible for the observed power law decay of the OTCFs.
Small Angle Neutron Scattering
Urban, Volker S [ORNL
2012-01-01T23:59:59.000Z
Small Angle Neutron Scattering (SANS) probes structural details at the nanometer scale in a non-destructive way. This article gives an introduction to scientists who have no prior small-angle scattering knowledge, but who seek a technique that allows elucidating structural information in challenging situations that thwart approaches by other methods. SANS is applicable to a wide variety of materials including metals and alloys, ceramics, concrete, glasses, polymers, composites and biological materials. Isotope and magnetic interactions provide unique methods for labeling and contrast variation to highlight specific structural features of interest. In situ studies of a material s responses to temperature, pressure, shear, magnetic and electric fields, etc., are feasible as a result of the high penetrating power of neutrons. SANS provides statistical information on significant structural features averaged over the probed sample volume, and one can use SANS to quantify with high precision the structural details that are observed, for example, in electron microscopy. Neutron scattering is non-destructive; there is no need to cut specimens into thin sections, and neutrons penetrate deeply, providing information on the bulk material, free from surface effects. The basic principles of a SANS experiment are fairly simple, but the measurement, analysis and interpretation of small angle scattering data involves theoretical concepts that are unique to the technique and that are not widely known. This article includes a concise description of the basics, as well as practical know-how that is essential for a successful SANS experiment.
Investigating the angle or response and maximum stability of a cohesive granular pile
Nowak, Sara Alice, 1982-
2004-01-01T23:59:59.000Z
In this thesis, I investigate the static and dynamic properties of a granular heap made cohesive by an interstitial fluid. I present the results of experimental work measuring the maximum angle of stability and the angle ...
A bulk-flow model of angled injection Lomakin bearings
Soulas, Thomas Antoine Theo
2001-01-01T23:59:59.000Z
A bulk-flow model for determination of the leakage and dynamic force characteristics of angled injection Lomakin bearings is presented. Zeroth- and first-order equations describe the equilibrium flow for a centered bearing and the perturbed flow...
Evers, Angela C.
2008-07-25T23:59:59.000Z
Frame walls enhanced with phase change materials (paraffin-based, hydrated salt-based, and eutectic) mixed in cellulose insulation were developed and tested. The frame walls were heated and allowed to cool in a dynamic wall simulator that replicated...
Dynamical coexistence of phases in molecular clusters Ana Proykova and Stoyan Pisov
Berry, R. Stephen
difficult to observe in computer simulations of SF6 clusters than of TeF6 clusters although the SF6 and TeF6 of the (SF6)89 cluster the relative energies of most of the linked minima differ only slightly orientationally ordered phase. At relevant temperatures, the fraction of the available phase space of the (SF6
Angle performance on optima MDxt
David, Jonathan; Kamenitsa, Dennis [Axcelis Technologies, Inc., 108 Cherry Hill Dr, Beverly, MA 01915 (United States)
2012-11-06T23:59:59.000Z
Angle control on medium current implanters is important due to the high angle-sensitivity of typical medium current implants, such as halo implants. On the Optima MDxt, beam-to-wafer angles are controlled in both the horizontal and vertical directions. In the horizontal direction, the beam angle is measured through six narrow slits, and any angle adjustment is made by electrostatically steering the beam, while cross-wafer beam parallelism is adjusted by changing the focus of the electrostatic parallelizing lens (P-lens). In the vertical direction, the beam angle is measured through a high aspect ratio mask, and any angle adjustment is made by slightly tilting the wafer platen prior to implant. A variety of tests were run to measure the accuracy and repeatability of Optima MDxt's angle control. SIMS profiles of a high energy, channeling sensitive condition show both the cross-wafer angle uniformity, along with the small-angle resolution of the system. Angle repeatability was quantified by running a channeling sensitive implant as a regular monitor over a seven month period and measuring the sheet resistance-to-angle sensitivity. Even though crystal cut error was not controlled for in this case, when attributing all Rs variation to angle changes, the overall angle repeatability was measured as 0.16 Degree-Sign (1{sigma}). A separate angle repeatability test involved running a series of V-curves tests over a four month period using low crystal cut wafers selected from the same boule. The results of this test showed the angle repeatability to be <0.1 Degree-Sign (1{sigma}).
Tackley, Paul J.
Three-dimensional structures and dynamics in the deep mantle: Effects of post-perovskite phase simulations of thermo- chemical mantle convection with multiple phase transitions (olivine-spinel-perovskite-post perovskite) are used to investigate the morphology of compositional and post- perovskite (PPV) boundary
Jimenez-Victory, Juan Carlos
1999-01-01T23:59:59.000Z
A study of the dynamic behavior of polycrystalline Shape Memory Alloys (SMA) under impact loading was proposed. The purpose of this study was to obtain basic understanding of the thermomechanical response of SMAs under ...
Nuclear Chiral Dynamics and Phases of QCD Physik-Department, Technische Universitat Munchen,
Weise, Wolfram
V. Isospin-asymmetric nuclear matter and neutron matter are also discussed. An outlook is given on new by a recently observed two-solar-mass neutron star. 1 Introduction QCD phase diagram: visions and facts
Optical phase dynamics in mutually coupled diode laser systems exhibiting power synchronization
Vishwa Pal; Awadhesh Prasad; R Ghosh
2011-11-10T23:59:59.000Z
We probe the physical mechanism behind the known phenomenon of power synchronization of two diode lasers that are mutually coupled via their delayed optical fields. In a diode laser, the amplitude and the phase of the optical field are coupled by the so-called linewidth enhancement factor, $\\alpha$. In this work, we explore the role of optical phases of the electric fields in amplitude (and hence power) synchronization through $\\alpha$ in such mutually delay-coupled diode laser systems. Our numerical results show that the synchronization of optical phases drives the powers of lasers to synchronized death regimes. We also find that as $\\alpha$ varies for different diode lasers, the system goes through a sequence of in-phase amplitude-death states. Within the windows between successive amplitude-death regions, the cross-correlation between the field amplitudes exhibits a universal power-law behaviour with respect to $\\alpha$.
Enhancement of two-phase flow images obtained using dynamic neutron radiography
Johns, Russell Craig
1995-01-01T23:59:59.000Z
-phase flow models in small diameter flow channels. An initial series of real-time neutron radiography experiments were performed at the Texas A&M University System, Texas Engineering Experiment Station, Nuclear Science Center Reactor (NSCR) to evaluate...
Rodriguez, E.; Rasmussen, B.
2015-01-01T23:59:59.000Z
) en- thalpy based switching which uses two-phase region length and evaporator outlet enthalpy as an event trigger, (2) void fraction based switching which includes the mean void fraction in the state variable vector, and (3) density based switching... which uses two-phase region density to trigger mass conservative switching. Nine case studies are performed through a combination of three different refrigerants, three different physical system parameters, and three different operating conditions...
Chemical dynamics in the gas phase: Time-dependent quantum mechanics of chemical reactions
Gray, S.K. [Argonne National Laboratory, IL (United States)
1993-12-01T23:59:59.000Z
A major goal of this research is to obtain an understanding of the molecular reaction dynamics of three and four atom chemical reactions using numerically accurate quantum dynamics. This work involves: (i) the development and/or improvement of accurate quantum mechanical methods for the calculation and analysis of the properties of chemical reactions (e.g., rate constants and product distributions), and (ii) the determination of accurate dynamical results for selected chemical systems, which allow one to compare directly with experiment, determine the reliability of the underlying potential energy surfaces, and test the validity of approximate theories. This research emphasizes the use of recently developed time-dependent quantum mechanical methods, i.e. wave packet methods.
High-order continuum kinetic method for modeling plasma dynamics in phase space
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Vogman, G. V.; Colella, P.; Shumlak, U.
2014-12-15T23:59:59.000Z
Continuum methods offer a high-fidelity means of simulating plasma kinetics. While computationally intensive, these methods are advantageous because they can be cast in conservation-law form, are not susceptible to noise, and can be implemented using high-order numerical methods. Advances in continuum method capabilities for modeling kinetic phenomena in plasmas require the development of validation tools in higher dimensional phase space and an ability to handle non-cartesian geometries. To that end, a new benchmark for validating Vlasov-Poisson simulations in 3D (x,vx,vy) is presented. The benchmark is based on the Dory-Guest-Harris instability and is successfully used to validate a continuum finite volumemore »algorithm. To address challenges associated with non-cartesian geometries, unique features of cylindrical phase space coordinates are described. Preliminary results of continuum kinetic simulations in 4D (r,z,vr,vz) phase space are presented.« less
Study of the nanobubble phase of aqueous NaCl solutions by dynamic light scattering
Bunkin, N F; Shkirin, A V [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Burkhanov, I S; Chaikov, L L [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Lomkova, A K [N.E. Bauman Moscow State Technical University, Moscow (Russian Federation)
2014-11-30T23:59:59.000Z
Aqueous NaCl solutions with different concentrations have been investigated by dynamic scattering of laser radiation. It is experimentally shown that these solutions contain scattering particles with a wide size distribution in a range of ?10 – 100 nm. The experimental results indirectly confirm the existence of quasi-stable gas nanobubbles in the bulk of aqueous ionic solutions. (light scattering)
Jimenez-Victory, Juan Carlos
1999-01-01T23:59:59.000Z
by the numerical solution of initial boundary value problems of a semi- infinite, one-dimensional SMA rod subjected to impact loading. Special focus was placed on the initiation and propagation of material phase transformation due to the presence of stress waves...
Anderson, G.W.
1991-09-16T23:59:59.000Z
An analytic treatment of the one Higgs doublet, electroweak phase transition is given. The phase transition is first order, occurs by the nucleation of thin walled bubbles and completes at a temperature where the order parameter, {l_angle}{phi}{r_angle}{sub T} is significantly smaller than it is when the origin becomes absolutely unstable. The rate of anomalous baryon number violation is an exponentially function of {l_angle}{phi}{r_angle}{sub T}. In very minimal extensions of the standard model it is quite easy to increase {l_angle}{phi}{r_angle}{sub T} so that anomalous baryon number violation is suppressed after completion of the phase transition. Hence baryogenesis at the electroweak phase transition is tenable in minimal of the standard model. In some cases additional phase transitions are possible. For a light Higgs boson, when the top quark mass is sufficiently large, the state where the Higgs field has a vacuum expectation value {l_angle}{phi}{r_angle} = 246 GeV is not the true minimum of the Higgs potential. When this is the case, and when the top quark mass exceeds some critical value, thermal fluctuations in the early universe would have rendered the state {l_angle}{phi}{r_angle} = 246 GeV unstable. The requirement that the state {l_angle}{phi}{r_angle} = 246 GeV is sufficiently long lived constrains the masses of the Higgs boson and the top quark. Finally, we consider whether local phase transitions can be induced by heavy particles which act as seeds for deformations in the scalar field.
Anderson, G.W.
1991-09-16T23:59:59.000Z
An analytic treatment of the one Higgs doublet, electroweak phase transition is given. The phase transition is first order, occurs by the nucleation of thin walled bubbles and completes at a temperature where the order parameter, {l angle}{phi}{r angle}{sub T} is significantly smaller than it is when the origin becomes absolutely unstable. The rate of anomalous baryon number violation is an exponentially function of {l angle}{phi}{r angle}{sub T}. In very minimal extensions of the standard model it is quite easy to increase {l angle}{phi}{r angle}{sub T} so that anomalous baryon number violation is suppressed after completion of the phase transition. Hence baryogenesis at the electroweak phase transition is tenable in minimal of the standard model. In some cases additional phase transitions are possible. For a light Higgs boson, when the top quark mass is sufficiently large, the state where the Higgs field has a vacuum expectation value {l angle}{phi}{r angle} = 246 GeV is not the true minimum of the Higgs potential. When this is the case, and when the top quark mass exceeds some critical value, thermal fluctuations in the early universe would have rendered the state {l angle}{phi}{r angle} = 246 GeV unstable. The requirement that the state {l angle}{phi}{r angle} = 246 GeV is sufficiently long lived constrains the masses of the Higgs boson and the top quark. Finally, we consider whether local phase transitions can be induced by heavy particles which act as seeds for deformations in the scalar field.
Yurtsever, E.; Onal, E. D.; Calvo, F. [Koc University, Rumelifeneriyolu, Sariyer, Istanbul TR-34450 (Turkey); LASIM, Universite de Lyon and CNRS UMR 5579, 43 Bd du 11 Novembre 1918, FR-69622 Villeurbanne Cedex (France)
2011-05-15T23:59:59.000Z
The stable structures and melting dynamics of clusters of identical ions bound by linear octupole radiofrequency traps are theoretically investigated by global optimization methods and molecular dynamics simulations. By varying the cluster sizes in the range of 10-1000 ions and the extent of trap anisotropy by more than one order of magnitude, we find a broad variety of stable structures based on multiple rings at small sizes evolving into tubular geometries at large sizes. The binding energy of these clusters is well represented by two contributions arising from isotropic linear and octupolar traps. The structures generally exhibit strong size effects, and chiral arrangements spontaneously emerge in many crystals. Sufficiently large clusters form nested, coaxial tubes with different thermal stabilities. As in isotropic octupolar clusters, the inner tubes melt at temperatures that are lower than the overall melting point.
Finite temperature spin-dynamics and phase transitions in spin-orbital models
Chen, C.-C.
2010-04-29T23:59:59.000Z
We study finite temperature properties of a generic spin-orbital model relevant to transition metal compounds, having coupled quantum Heisenberg-spin and Ising-orbital degrees of freedom. The model system undergoes a phase transition, consistent with that of a 2D Ising model, to an orbitally ordered state at a temperature set by short-range magnetic order. At low temperatures the orbital degrees of freedom freeze-out and the model maps onto a quantum Heisenberg model. The onset of orbital excitations causes a rapid scrambling of the spin spectral weight away from coherent spin-waves, which leads to a sharp increase in uniform magnetic susceptibility just below the phase transition, reminiscent of the observed behavior in the Fe-pnictide materials.
Super energy saver heat pump with dynamic hybrid phase change material
Ally, Moonis Raza (Oak Ridge, TN) [Oak Ridge, TN; Tomlinson, John Jager (Knoxville, TN) [Knoxville, TN; Rice, Clifford Keith (Clinton, TN) [Clinton, TN
2010-07-20T23:59:59.000Z
A heat pump has a refrigerant loop, a compressor in fluid communication with the refrigerant loop, at least one indoor heat exchanger in fluid communication with the refrigerant loop, and at least one outdoor heat exchanger in fluid communication with the refrigerant loop. The at least one outdoor heat exchanger has a phase change material in thermal communication with the refrigerant loop and in fluid communication with an outdoor environment. Other systems, devices, and methods are described.
Dmitriy G. Pavlov; Sergey S. Kokarev
2009-10-20T23:59:59.000Z
Within the framework of Berwald-Moor Geometry in H_3, the paper studies the construction of additive poly-angles (bingles and tringles). It is shown that, considering additiveness in the large, there exist an infinity of such poly-angles.
Absorbing Phase Transitions and Dynamic Freezing in Running Active Matter Systems
C. Reichhardt; C. J. Olson Reichhardt
2014-06-12T23:59:59.000Z
We examine a two-dimensional system of sterically repulsive interacting disks where each particle runs in a random direction. This system is equivalent to a run-and-tumble dynamics system in the limit where the run time is infinite. At low densities, we find a strongly fluctuating state composed of transient clusters. Above a critical density that is well below the density at which non-active particles would crystallize, the system can organize into a drifting quiescent or frozen state where the fluctuations are lost and large crystallites form surrounded by a small density of individual particles. Although all the particles are still moving, their paths form closed orbits. The average transient time to organize into the quiescent state diverges as a power law upon approaching the critical density from above. We compare our results to the random organization observed for periodically sheared systems that can undergo an absorbing transition from a fluctuating state to a dynamical non-fluctuating state. In the random organization studies, the system organizes to a state in which the particles no longer interact; in contrast, we find that the randomly running active matter organizes to a strongly interacting dynamically jammed state. We show that the transition to the frozen state is robust against a certain range of stochastic fluctuations. We also examine the effects of adding a small number of pinned particles to the system and find that the transition to the frozen state shifts to significantly lower densities and arises via the nucleation of faceted crystals centered at the obstacles.
Spinning angle optical calibration apparatus
Beer, Stephen K. (Morgantown, WV); Pratt, II, Harold R. (Morgantown, WV)
1991-01-01T23:59:59.000Z
An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning "magic angles" in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the "magic angle" of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation or graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning "magic angle" of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position.
Neben, A R; Hewitt, J N; Bernardi, G; Bowman, J D; Briggs, F; Cappallo, R J; Deshpande, A A; Goeke, R; Greenhill, L J; Hazelton, B J; Johnston-Hollitt, M; Kaplan, D L; Lonsdale, C J; McWhirter, S R; Mitchell, D A; Morales, M F; Morgan, E; Oberoi, D; Ord, S M; Prabu, T; Shankar, N Udaya; Srivani, K S; Subrahmanyan, R; Tingay, S J; Wayth, R B; Webster, R L; Williams, A; Williams, C L
2015-01-01T23:59:59.000Z
Detection of the fluctuations in 21 cm line emission from neutral hydrogen during the Epoch of Reionization in thousand hour integrations poses stringent requirements on calibration and image quality, both of which necessitate accurate primary beam models. The Murchison Widefield Array (MWA) uses phased array antenna elements which maximize collecting area at the cost of complexity. To quantify their performance, we have developed a novel beam measurement system using the 137 MHz ORBCOMM satellite constellation and a reference dipole antenna. Using power ratio measurements, we measure the {\\it in situ} beampattern of the MWA antenna tile relative to that of the reference antenna, canceling the variation of satellite flux or polarization with time. We employ angular averaging to mitigate multipath effects (ground scattering), and assess environmental systematics with a null experiment in which the MWA tile is replaced with a second reference dipole. We achieve beam measurements over 30 dB dynamic range in beam...
Carlisle, Bruce Scott
1994-01-01T23:59:59.000Z
AN EVAI. UATION OF THE NEUTRON RADIOGRAPHY FACILITY AT THE NUCLEAR SCIENCF- CENTER FOR DYNAMIC IMAGING OF TWO-PHASE HYDROGENOUS FLUIDS A Thesis By BRUCE SCOTT CARLlSLE Submitted to the Office of Graduate Studies of Texas Ag-M University... in partiat fulfillment of the requirements for the degree of MASTER OF SCPENCF. August 1994 Major Subject: Nuclear Engineering AN EVALUATION OF THE NEUTRON RADIOGRAPHY FACILITY AT THE NUCLEAR SCIENCE CENTFR FOR THE DYNAMIC IMAGING OF TWO...
Shu, Chuan-Cun; Henriksen, Niels E. [Department of Chemistry, Building 207, Technical University of Denmark, DK-2800, Kongens Lyngby (Denmark)
2012-01-28T23:59:59.000Z
We implement phase-only shaped laser pulses within quantum optimal control theory for laser-molecule interaction. This approach is applied to the indirect photofragmentation dynamics of NaI in the weak-field limit. It is shown that optimized phase-modulated pulses with a fixed frequency distribution can substantially modify transient dissociation probabilities as well as the momentum distribution associated with the relative motion of Na and I.
Dynamics of Longitudinal Phase-Space Modulations in an rf Compressor for Electron Beams
Venturini, M.; Migliorati, M.; Ronsivalle, C.; Ferrario, M.; Vaccarezza, C.
2010-05-21T23:59:59.000Z
Free Electron Lasers (FELs) operating in the UV or x-ray radiation spectrum require peak beam currents that are generally higher than those obtainable by present electron sources, thus making bunch compression necessary. Compression, however, may heighten the effects of collective forces and degrade the beam quality. In this paper they provide a framework for investigating some of these effects in rf compressors by focusing on the longitudinal dynamics of small-amplitude density perturbations, which have the potential to cause the disruptive appearance of the so-called microbunching instability. They develop a linear theory valid for low-to-moderate compression factors under the assumption of a 1D impedance model of longitudinal space charge and provide validation against macroparticle simulations.
A molecular dynamics study of nuclear quantum effect on the diffusion of hydrogen in condensed phase
Nagashima, Hiroki; Tokumasu, Takashi [Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi (Japan); Tsuda, Shin-ichi [Shinshu University, 77-7 Minamibori, Nagano, Nagano (Japan); Tsuboi, Nobuyuki [Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu, Fukuoka (Japan); Koshi, Mitsuo [Yokohama National University, 79-7 Tokiwadai, Hodogaya, Yokohama, Kanagawa (Japan); Hayashie, A. Koichi [AoyamaGakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa (Japan)
2014-10-06T23:59:59.000Z
In this paper, the quantum effect of hydrogen molecule on its diffusivity is analyzed using Molecular Dynamics (MD) method. The path integral centroid MD (CMD) method is applied for the reproduction method of time evolution of the molecules. The diffusion coefficient of liquid hydrogen is calculated using the Green-Kubo method. The simulation is performed at wide temperature region and the temperature dependence of the quantum effect of hydrogen molecule is addressed. The calculation results are compared with those of classical MD results. As a result, it is confirmed that the diffusivity of hydrogen molecule is changed depending on temperature by the quantum effect. It is clarified that this result can be explained that the dominant factor by quantum effect on the diffusivity of hydrogen changes from the swollening the potential to the shallowing the potential well around 30 K. Moreover, it is found that this tendency is related to the temperature dependency of the ratio of the quantum kinetic energy and classical kinetic energy.
Penny, Will
2009-01-01T23:59:59.000Z
Please cite this article in press as: Penny WD, et al. Dynamic Causal Models for phase coupling. J of the Dynamic Causal Modelling (DCM) framework to the analysis of phase-coupled data. A weakly coupled synchronization processes, measured with brain imaging data, can be described using weakly coupled oscillator (WCO
Furukawa, Toru
2002-01-01T23:59:59.000Z
A three-dimensional bubble reconstruction method is proposed in this thesis to analyze two-phase bubbly flows. Gas/liquid two-phase flows have important roles in the nuclear and chemical industries and other engineering fields...
of a Phase Change Material Wall Damien Davida,b,c, , Fr´ed´eric Kuznika,b,c , Jean-Jacques Rouxa,b,c a CETHIL, the use of Phase Change Materials (PCM) allows the storage/release of energy from solar radiation, Phase Change Material, Convective Heat Transfer Coefficient. 1. Introduction Nowadays, thermal energy
OPENING ANGLES OF COLLAPSAR JETS
Mizuta, Akira; Ioka, Kunihito [Theory Center, Institute of Particle and Nuclear Studies, KEK, Tsukuba 305-0801 (Japan)
2013-11-10T23:59:59.000Z
We investigate the jet propagation and breakout from the stellar progenitor for gamma-ray burst (GRB) collapsars by performing two-dimensional relativistic hydrodynamic simulations and analytical modeling. We find that the jet opening angle is given by ?{sub j} ? 1/5?{sub 0} and infer the initial Lorentz factor of the jet at the central engine, ?{sub 0}, is a few for existing observations of ?{sub j}. The jet keeps the Lorentz factor low inside the star by converging cylindrically via collimation shocks under the cocoon pressure and accelerates at jet breakout before the free expansion to a hollow-cone structure. In this new picture, the GRB duration is determined by the sound crossing time of the cocoon, after which the opening angle widens, reducing the apparent luminosity. Some bursts violating the maximum opening angle ?{sub j,{sub max}} ? 1/5 ? 12° imply the existence of a baryon-rich sheath or a long-acting jet. We can explain the slopes in both Amati and Yonetoku spectral relations using an off-centered photosphere model, if we make only one assumption that the total jet luminosity is proportional to the initial Lorentz factor of the jet. We also numerically calibrate the pre-breakout model (Bromberg et al.) for later use.
Alfè, Dario
, military, industrial processing, automotive, and other applications. As the mechanical properties depend significant technological implications in the aerospace industry because the phase formation lowers toughness
Skrynnikov, Nikolai
be made that 180° pulses refocus the chemical shift evolution and thus prevent the build-up of randomlyMicrosecond time-scale dynamics from relaxation in the rotating frame: experiments using spin lockÞðÀxÞðxÞðÀxÞ . . ., is proposed as a new technique to probe microsecond time-scale dynamics. A series of R1q measurements using
New York at Stoney Brook, State University of
is required for the study of cavitation induced by strong rarefaction waves. The robustness of the proposed of hydrodynamics and thermal e#ects in liquidvapor phase transitions is en countered in many applicationsequilibrium e#ects. A complete macroscopic description of phase changes requires the coupling of hydrodynamics
Hyperbolic Dynamics Todd Fisher
Fisher, Todd
Hyperbolic Dynamics Todd Fisher tfisher@math.umd.edu Department of Mathematics University of Maryland, College Park Hyperbolic Dynamics p. 1/3 #12;What is a dynamical system? Phase space X, elements possible states Hyperbolic Dynamics p. 2/3 #12;What is a dynamical system? Phase space X, elements
Phase modulated rotor angle encoder for switched reluctance motor drive
Mahajan, Shailendra
1993-01-01T23:59:59.000Z
sensor. In an inexpensive systein, the rotor position sensor comprises of a magnetized ring along with Hall etfect sensors or opto-interrupters with slotted clisk. An optical sensor has a, light emitting diode which acts as a light transmitter, enid a...
Phase modulated rotor angle encoder for switched reluctance motor drive
Mahajan, Shailendra
1993-01-01T23:59:59.000Z
Advantages of the switched reluctance motor (SRM) drive makes it an attractive candidate for replacing many adjustable speed ac and dc drives, in both industrial and consumer applications. The switched reluctance drives ...
Methods for magnetic resonance analysis using magic angle technique
Hu, Jian Zhi (Richland, WA); Wind, Robert A. (Kennewick, WA); Minard, Kevin R. (Kennewick, WA); Majors, Paul D. (Kennewick, WA)
2011-11-22T23:59:59.000Z
Methods of performing a magnetic resonance analysis of a biological object are disclosed that include placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. In particular embodiments the method includes pulsing the radio frequency to provide at least two of a spatially selective read pulse, a spatially selective phase pulse, and a spatially selective storage pulse. Further disclosed methods provide pulse sequences that provide extended imaging capabilities, such as chemical shift imaging or multiple-voxel data acquisition.
Shu Luo
2011-12-14T23:59:59.000Z
Enlightened by the idea of the 3 times 3 CKM angle matrix proposed recently by Harrison et al., we introduce the Dirac angle matrix Phi and the Majorana angle matrix Psi in the lepton sector for Dirac and Majorana neutrinos respectively. We show that in presence of the CP violation, the angle matrix Phi or Psi is entirely equivalent to the complex MNS matrix V itself, but has the advantage of being real, phase rephasing invariant, directly associated to the leptonic unitarity triangles (UTs) and do not depend on any particular parametrization of V. In this paper, we further analyzed how the angle matrices evolve with the energy scale. The one-loop Renormalization Group Equations (RGEs) of Phi, Psi and some other rephasing invariant parameters are derived and the numerical analysis is performed to compare between the case of Dirac and Majorana neutrinos. Different neutrino mass spectra are taken into account in our calculation. We find that apparently different from the case of Dirac neutrinos, for Majorana neutrinos the RG-evolutions of Phi, Psi and the Jarlskog strongly depend on the Majorana-type CP-violating parameters and are quite sensitive to the sign of Delta m^{2}_{31}. They may receive significant radiative corrections in the MSSM if three neutrino masses are nearly degenerate.
Luo, Shu
2011-01-01T23:59:59.000Z
Enlightened by the idea of the 3 times 3 CKM angle matrix proposed recently by Harrison et al., we introduce the Dirac angle matrix Phi and the Majorana angle matrix Psi in the lepton sector for Dirac and Majorana neutrinos respectively. We show that in presence of the CP violation, the angle matrix Phi or Psi is entirely equivalent to the complex MNS matrix V itself, but has the advantage of being real, phase rephasing invariant, directly associated to the leptonic unitarity triangles (UTs) and do not depend on any particular parametrization of V. In this paper, we further analyzed how the angle matrices evolve with the energy scale. The one-loop Renormalization Group Equations (RGEs) of Phi, Psi and some other rephasing invariant parameters are derived and the numerical analysis is performed to compare between the case of Dirac and Majorana neutrinos. Different neutrino mass spectra are taken into account in our calculation. We find that apparently different from the case of Dirac neutrinos, for Majorana ne...
T. P. Shestakova
2013-03-06T23:59:59.000Z
Among theoretical issues in General Relativity the problem of constructing its Hamiltonian formulation is still of interest. The most of attempts to quantize Gravity are based upon Dirac generalization of Hamiltonian dynamics for system with constraints. At the same time there exists another way to formulate Hamiltonian dynamics for constrained systems guided by the idea of extended phase space. We have already considered some features of this approach in the previous MG12 Meeting by the example of a simple isotropic model. Now we apply the approach to a generalized spherically symmetric model which imitates the structure of General Relativity much better. In particular, making use of a global BRST symmetry and the Noether theorem, we construct the BRST charge that generates correct gauge transformations for all gravitational degrees of freedom.
Reshmeen, Silvia
2009-12-23T23:59:59.000Z
ABSTRACT This thesis presents the results of an experimental study to determine the optimum placement and the thermal performance of a Phase Change Materials (PCMs) thermal shield incorporated into frame wall insulation systems for the purpose...
"Magic Angle Precession" Bernd Binder
Binder, Bernd
by geometric phases, which are induced by high- speed relativistic rotations and are relevant to propulsion, quark, confinement, heavy nuclei, Sommerfeld, fine structure, propulsion, SO(3), nonlinear, chaotic maps in the vicinity of a magnetic monopole or singularity (Dirac, 1931) that could be located on the tip
Caustic graphene plasmons with Kelvin angle
Shi, Xihang; Gao, Fei; Xu, Hongyi; Yang, Zhaoju; Zhang, Baile
2015-01-01T23:59:59.000Z
A century-long argument made by Lord Kelvin that all swimming objects have an effective Mach number of 3, corresponding to the Kelvin angle of 19.5 degree for ship waves, has been recently challenged with the conclusion that the Kelvin angle should gradually transit to the Mach angle as the ship velocity increases. Here we show that a similar phenomenon can happen for graphene plasmons. By analyzing the caustic wave pattern of graphene plasmons stimulated by a swift charged particle moving uniformly above graphene, we show that at low velocities of the charged particle, the caustics of graphene plasmons form the Kelvin angle. At large velocities of the particle, the caustics disappear and the effective semi-angle of the wave pattern approaches the Mach angle. Our study introduces caustic wave theory to the field of graphene plasmonics, and reveals a novel physical picture of graphene plasmon excitation during electron energy-loss spectroscopy measurement.
Dynamical modeling of tidal streams
Bovy, Jo, E-mail: bovy@ias.edu [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)
2014-11-01T23:59:59.000Z
I present a new framework for modeling the dynamics of tidal streams. The framework consists of simple models for the initial action-angle distribution of tidal debris, which can be straightforwardly evolved forward in time. Taking advantage of the essentially one-dimensional nature of tidal streams, the transformation to position-velocity coordinates can be linearized and interpolated near a small number of points along the stream, thus allowing for efficient computations of a stream's properties in observable quantities. I illustrate how to calculate the stream's average location (its 'track') in different coordinate systems, how to quickly estimate the dispersion around its track, and how to draw mock stream data. As a generative model, this framework allows one to compute the full probability distribution function and marginalize over or condition it on certain phase-space dimensions as well as convolve it with observational uncertainties. This will be instrumental in proper data analysis of stream data. In addition to providing a computationally efficient practical tool for modeling the dynamics of tidal streams, the action-angle nature of the framework helps elucidate how the observed width of the stream relates to the velocity dispersion or mass of the progenitor, and how the progenitors of 'orphan' streams could be located. The practical usefulness of the proposed framework crucially depends on the ability to calculate action-angle variables for any orbit in any gravitational potential. A novel method for calculating actions, frequencies, and angles in any static potential using a single orbit integration is described in the Appendix.
Realizing in-plane surface diffraction by x-ray multiple-beam diffraction with large incidence angle
Huang, Xian-Rong, E-mail: xiahuang@aps.anl.gov; Gog, Thomas; Assoufid, Lahsen [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Peng, Ru-Wen, E-mail: rwpeng@nju.edu.cn [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Siddons, D. P. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)
2014-11-03T23:59:59.000Z
Based on rigorous dynamical-theory calculations, we demonstrate the principle of an x-ray multiple-beam diffraction (MBD) scheme that overcomes the long-lasting difficulties of high-resolution in-plane diffraction from crystal surfaces. This scheme only utilizes symmetric reflection geometry with large incident angles but activates the out-of-plane and in-plane diffraction processes simultaneously and separately in the continuous MBD planes. The in-plane diffraction is realized by detoured MBD, where the intermediate diffracted waves propagate parallel to the surface, which corresponds to an absolute Bragg surface diffraction configuration that is extremely sensitive to surface structures. A series of MBD diffraction and imaging techniques may be developed from this principle to study surface/interface (misfit) strains, lateral nanostructures, and phase transitions of a wide range of (pseudo)cubic crystal structures, including ultrathin epitaxial films and multilayers, quantum dots, strain-engineered semiconductor or (multi)ferroic materials, etc.
Phase Transformations in Binary Colloidal Monolayers
Ye Yang; Lin Fu; Catherine Marcoux; Joshua E. S. Socolar; Patrick Charbonneau; Benjamin B. Yellen
2015-02-10T23:59:59.000Z
Phase transformations can be difficult to characterize at the microscopic level due to the inability to directly observe individual atomic motions. Model colloidal systems, by contrast, permit the direct observation of individual particle dynamics and of collective rearrangements, which allows for real-space characterization of phase transitions. Here, we study a quasi-two-dimensional, binary colloidal alloy that exhibits liquid-solid and solid-solid phase transitions, focusing on the kinetics of a diffusionless transformation between two crystal phases. Experiments are conducted on a monolayer of magnetic and nonmagnetic spheres suspended in a thin layer of ferrofluid and exposed to a tunable magnetic field. A theoretical model of hard spheres with point dipoles at their centers is used to guide the choice of experimental parameters and characterize the underlying materials physics. When the applied field is normal to the fluid layer, a checkerboard crystal forms; when the angle between the field and the normal is sufficiently large, a striped crystal assembles. As the field is slowly tilted away from the normal, we find that the transformation pathway between the two phases depends strongly on crystal orientation, field strength, and degree of confinement of the monolayer. In some cases, the pathway occurs by smooth magnetostrictive shear, while in others it involves the sudden formation of martensitic plates.
Bagaev, V. S.; Krivobok, V. S., E-mail: krivobok@lebedev.ru; Nikolaev, S. N.; Onishchenko, E. E.; Pruchkina, A. A.; Aminev, D. F.; Skorikov, M. L. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Lobanov, D. N.; Novikov, A. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)
2013-11-15T23:59:59.000Z
The dynamics of the phase transition from an electron-hole plasma to an exciton gas is studied during pulsed excitation of heterostructures with Si{sub 1?x}Ge{sub x}/Si quantum wells. The scenario of the phase transition is shown to depend radically on the germanium content in the Si{sub 1?x}Ge{sub x} layer. The electron-hole system decomposes into a rarefied exciton and a dense plasma phases for quantum wells with a germanium content x = 3.5% in the time range 100–500 ns after an excitation pulse. In this case, the electron-hole plasma existing in quantum wells has all signs of an electron-hole liquid. A qualitatively different picture of the phase transition is observed for quantum wells with x = 9.5%, where no separation into phases with different electronic spectra is detected. The carrier recombination in the electron-hole plasma leads a gradual weakening of screening and the appearance of exciton states. For a germanium content of 5–7%, the scenario of the phase transition is complex: 20–250 ns after an excitation pulse, the properties of the electron-hole system are described in terms of a homogeneous electron-hole plasma, whereas its separation into an electron-hole liquid and an exciton gas is detected after 350 ns. It is shown that, for the electron-hole liquid to exist in quantum wells with x = 5–7% Ge, the exciton gas should have a substantially higher density than in quantum wells with x = 3.5% Ge. This finding agrees with a decrease in the depth of the local minimum of the electron-hole plasma energy with increasing germanium concentration in the SiGe layer. An increase in the density of the exciton gas coexisting with the electron-hole liquid is shown to enhance the role of multiparticle states, which are likely to be represented by trions T{sup +} and biexcitons, in the exciton gas.
Limiting Emission Angle for Improved Solar Cell
Limiting Emission Angle for Improved Solar Cell Performance While direct light enters a solar cell will explore the potential benefits to limiting the emission angles of realistic solar cells, with efficiencies cooling, waste heat recovery and solar electricity generation, low values of the thermoelectric figure
The phase-lock dynamics of the laser wakefield acceleration with an intensity-decaying laser pulse
Li, Wentao; Liu, Jiansheng, E-mail: michaeljs-liu@siom.ac.cn; Wang, Wentao; Zhang, Zhijun; Chen, Qiang; Tian, Ye; Qi, Rong; Yu, Changhai; Wang, Cheng; Li, Ruxin, E-mail: ruxinli@mail.shcnc.ac.cn; Xu, Zhizhan, E-mail: zzxu@mail.shcnc.ac.cn [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box: 800-211, Shanghai 201800 (China); Tajima, T. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)
2014-03-03T23:59:59.000Z
An electron beam with the maximum energy extending up to 1.8?GeV, much higher than the dephasing limit, is experimentally obtained in the laser wakefield acceleration with the plasma density of 3.5?×?10{sup 18}?cm{sup ?3}. With particle in cell simulations and theoretical analysis, we find that the laser intensity evolution plays a major role in the enhancement of the electron energy gain. While the bubble length decreases due to the intensity-decay of the laser pulse, the phase of the electron beam in the wakefield can be locked, which contributes to the overcoming of the dephasing. Moreover, the laser intensity evolution is described for the phase-lock acceleration of electrons in the uniform plasma, confirmed with our own simulation. Since the decaying of the intensity is unavoidable in the long distance propagation due to the pump depletion, the energy gain of the high energy laser wakefield accelerator can be greatly enhanced if the current process is exploited.
Polarons and Mobile Impurities Near a Quantum Phase Transition
Shadkhoo, Shahriar
2015-01-01T23:59:59.000Z
dynamics in water by high energy resolution inelastic x-rayto energy and pressure. The bonds and angles in the water
Lü, Hongfeng [Department of Applied Physics, College of Science, China Agricultural University, Beijing 100083 (China); Wang, Shanying [Department of Physics, Tsinghua University, Beijing 100084 (China); Wang, Xiaosu, E-mail: xiaosuwang@cau.edu.cn [Department of Applied Physics, College of Science, China Agricultural University, Beijing 100083 (China); Department of Physics, Tsinghua University, Beijing 100084 (China)
2014-03-28T23:59:59.000Z
The structural, electronic and dynamical properties of the cubic, tetragonal and rhombohedral phases of a lead-free ferroelectrics, (Na{sub 0.5}Bi{sub 0.5})TiO{sub 3} (NBT), have been studied with a density functional formalism. The direct band gap is determined to be 2?3?eV for three phases, suggesting them to be good optical material. The equilibrium structures were given, and the importance of Bi atom in the low-symmetry ferroelectric phases were investigated with the electron localization functions analysis. The vibration modes at the ? point were calculated to provide a basis for analyzing the Raman and IR spectra. Soft modes were found in both the cubic and the tetragonal phases, providing a clue in understanding the ferroelectric phase transition in NBT.
Contact Angle Hysteresis on Superhydrophobic Stripes
Alexander L. Dubov; Ahmed Mourran; Martin Möller; Olga I. Vinogradova
2014-07-21T23:59:59.000Z
We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, $\\phi_S$. It is shown that the receding regime is determined by a longitudinal sliding motion the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e. is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with $\\phi_S$, in contrast to predictions of the Cassie equation. To interpret this we develop a simple theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the elastic energy of strong defects at the borders of stripes, which scales as $\\phi_S^2 \\ln \\phi_S$. The advancing contact angle was found to be anisotropic, except as in a dilute regime, and its value is determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on $\\phi_S$, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at $\\phi_S\\simeq 0.5$. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be proportional to $\\phi_S^2$. Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when $\\phi_S\\leq 0.2$.
Long range correlations and folding angle with applications to ?-helical proteins
Krokhotin, Andrey, E-mail: Andrei.Krokhotine@cern.ch [Department of Physics and Astronomy, Uppsala University, P.O. Box 803, S-75108, Uppsala (Sweden)] [Department of Physics and Astronomy, Uppsala University, P.O. Box 803, S-75108, Uppsala (Sweden); Nicolis, Stam, E-mail: Stam.Nicolis@lmpt.univ-tours.fr [Laboratoire de Mathematiques et Physique Theorique CNRS UMR 6083, Fédération Denis Poisson, Université de Tours, Parc de Grandmont, F37200 Tours (France)] [Laboratoire de Mathematiques et Physique Theorique CNRS UMR 6083, Fédération Denis Poisson, Université de Tours, Parc de Grandmont, F37200 Tours (France); Niemi, Antti J., E-mail: Antti.Niemi@physics.uu.se [Department of Physics and Astronomy, Uppsala University, P.O. Box 803, S-75108, Uppsala (Sweden); Laboratoire de Mathematiques et Physique Theorique CNRS UMR 6083, Fédération Denis Poisson, Université de Tours, Parc de Grandmont, F37200 Tours (France); Department of Physics, Beijing Institute of Technology, Haidian District, Beijing 100081 (China)
2014-03-07T23:59:59.000Z
The conformational complexity of chain-like macromolecules such as proteins and other linear polymers is much larger than that of point-like atoms and molecules. Unlike particles, chains can bend, twist, and even become knotted. Thus chains might also display a much richer phase structure. Unfortunately, it is not very easy to characterize the phase of a long chain. Essentially, the only known attribute is the radius of gyration. The way how it changes when the degree of polymerization becomes different, and how it evolves when the ambient temperature and solvent properties change, is commonly used to disclose the phase. But in any finite length chain there are corrections to scaling that complicate the detailed analysis of the phase structure. Here we introduce a quantity that we call the folding angle to identify and scrutinize the phase structure, as a complement to the radius of gyration. We argue for a mean-field level relationship between the folding angle and the scaling exponent in the radius of gyration. We then estimate the value of the folding angle in the case of crystallographic ?-helical protein structures in the Protein Data Bank. We also show how the experimental value of the folding angle can be obtained computationally, using a semiclassical Born-Oppenheimer description of ?-helical chiral chains.
The Provision of IP Crossing Angles for the SSC
Ritson, David M
2003-07-11T23:59:59.000Z
Luminosity is to be produced at the SSC collider by crossing with finite angle the counter circulating proton beams at each interaction point (IP). Such a crossing angle introduces unwanted dispersion in the high beta triplet quadrupoles adjacent to the IPs which must be corrected out. they propose to produce variable crossing conditions at each IP with local steering dipoles adjusted to give required slopes and displacements for each IP. The anomalous dispersion introduced by these orbit displacements will be corrected in the arcs (dispersive region) just prior to entry and exit into the IRs with opposite polarity quadrupole pairs separated by 90{sup o} in phase, a late correction scheme. Such pairs cause minimal change to the betatron functions but produce dispersion that can be set to cancel the anomalous dispersion. The IR design is such that the phase advance between correctors and the IP triplet gives efficient full local anomalous dispersion cancellation. The proposed system is to be formed from standard SSC corrector elements and will provide the range of crossing conditions required for collision optics and for separating the beams at injection.
Small Angle X-Ray Scattering Detector
Hessler, Jan P.
2004-06-15T23:59:59.000Z
A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., qmax/qmin approx=lO0.
No Collective Neutrino Flavor Conversions during the Supernova Accretion Phase
Chakraborty, Sovan; Mirizzi, Alessandro; Saviano, Ninetta; Tomas, Ricard [II Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Fischer, Tobias [GSI, Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt (Germany); Technische Universitaet Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt (Germany)
2011-10-07T23:59:59.000Z
We perform a dedicated study of the supernova (SN) neutrino flavor evolution during the accretion phase, using results from recent neutrino radiation hydrodynamics simulations. In contrast to what was expected in the presence of only neutrino-neutrino interactions, we find that the multiangle effects associated with the dense ordinary matter suppress collective oscillations. The matter suppression implies that neutrino oscillations will start outside the neutrino decoupling region and therefore will have a negligible impact on the neutrino heating and the explosion dynamics. Furthermore, the possible detection of the next galactic SN neutrino signal from the accretion phase, based on the usual Mikheyev-Smirnov-Wolfenstein effect in the SN mantle and Earth matter effects, can reveal the neutrino mass hierarchy in the case that the mixing angle {theta}{sub 13} is not very small.
Rotational Rehybridization and the High Temperature Phase of UC2
Wen, Xiaodong; Rudin, Sven P.; Batista, Enrique R.; Clark, David L.; Scuseria, Gustavo E.; Martin, Richard L.
2012-12-03T23:59:59.000Z
The screened hybrid approximation (HSE) of density functional theory (DFT) is used to examine the structural, optical, and electronic properties of the high temperature phase, cubic UC(2). This phase contains C(2) units with a computed C-C distance of 1.443 Å which is in the range of a CC double bond; U is formally 4+, C(2) 4-. The closed shell paramagnetic state (NM) was found to lie lowest. Cubic UC(2) is found to be a semiconductor with a narrow gap, 0.4 eV. Interestingly, the C(2) units connecting two uranium sites can rotate freely up to an angle of 30°, indicating a hindered rotational solid. Ab-initio molecular dynamic simulations (HSE) show that the rotation of C(2) units in the low temperature phase (tetragonal UC(2)) occurs above 2000 K, in good agreement with experiment. The computed energy barrier for the phase transition from tetragonal UC(2) to cubic UC(2) is around 1.30 eV per UC(2). What is fascinating about this system is that at high temperature, the phase transformation to the cubic phase is associated with a rehybridization of the C atoms from sp to sp(3).
Ship wakes: Kelvin or Mach angle?
Rabaud, Marc
2013-01-01T23:59:59.000Z
From the analysis of a set of airborne images of ship wakes, we show that the wake angles decrease as $U^{-1}$ at large velocities, in a way similar to the Mach cone for supersonic airplanes. This previously unnoticed Mach-like regime is in contradiction with the celebrated Kelvin prediction of a constant angle of $19.47\\degree$ independent of the ship's speed. We propose here a model, confirmed by numerical simulations, in which the finite size of the disturbance explains this transition between the Kelvin and Mach regimes at a Froude number $Fr = U/\\sqrt{gL} \\simeq 0.5$, where $L$ is the hull ship length.
Imaging properties of supercritical angle fluorescence optics
Enderlein, Jörg
Imaging properties of supercritical angle fluorescence optics J¨org Enderlein,1,4, Ingo Gregor,1.ruckstuhl@pci.uzh.ch 4http://www.joerg-enderlein.de enderlein@physik3.gwdg.de Abstract: In recent years, new optical the detection volume within one wavelength to an interface. For conventional optical systems with high numerical
Boiler Efficiency--Consider All the Angles
Blakeley, C. P.
1981-01-01T23:59:59.000Z
BOILER EFFICIENCY--CONSIDER ALL THE ANGLES Christopher P. Blakeley Honeywell r>rocess !lanagement Systems Division Fort Washington, Pennsylvania The cost of steam has become a very real part of Product cost. U.S.lndustry strives to become more...
Angle Coverage in Wireless Sensor Networks Chow Kit Yee
Tam, Vincent W. L.
. We study the scheduling problem to monitor a target continuously with full angle coverage. Several
The effect of knee separation and backrest angle on lumbar lordosis angle in various seated postures
Bolen, Bradley Kyle
1999-01-01T23:59:59.000Z
or human comfort levels while seated. Given that the neutral posture of the legs has an abduction angle of lg-deg, it is reasonable to assume that the human body is affected in some way when the legs stray from this angle. Certainly future research... to better replicate their individual sitting posture. The subjects' legs were supported so that the thighs were approximately parallel to the ground. Knee angle was not strictly maintained, but kept constant at approximately 90-deg in all sitting postures...
Is the friction angle the maximum slope of a free surface of a non cohesive material?
A. Modaressi; P. Evesque
2005-07-13T23:59:59.000Z
Starting from a symmetric triangular pile with a horizontal basis and rotating the basis in the vertical plane, we have determined the evolution of the stress distribution as a function of the basis inclination using Finite Elements method with an elastic-perfectly plastic constitutive model, defined by its friction angle, without cohesion. It is found that when the yield function is the Drucker-Prager one, stress distribution satisfying equilibrium can be found even when one of the free-surface slopes is larger than the friction angle. This means that piles with a slope larger than the friction angle can be (at least) marginally stable and that slope rotation is not always a destabilising perturbation direction. On the contrary, it is found that the slope cannot overpass the friction angle when a Mohr-Coulomb yield function is used. Theoretical explanation of these facts is given which enlightens the role plaid by the intermediate principal stress in both cases of the Mohr-Coulomb criterion and of the Drucker-Prager one. It is then argued that the Mohr-Coulomb criterion assumes a spontaneous symmetry breaking, as soon as the two smallest principal stresses are different ; this is not physical most likely; so this criterion shall be replaced by a Drucker-Prager criterion in the vicinity of the equality, which leads to the previous anomalous behaviour ; so these numerical computations enlighten the avalanche process: they show that no dynamical angle larger than the static one is needed to understand avalanching. It is in agreement with previous experimental results. Furthermore, these results show that the maximum angle of repose can be modified using cyclic rotations; we propose a procedure that allows to achieve a maximum angle of repose to be equal to the friction angle .
Classical potential describes martensitic phase transformations between the , , and titanium phases
Wilkins, John
Classical potential describes martensitic phase transformations between the , , and titanium phases of titanium that includes nucleation and growth requires an accurate classical potential. Optimization transformations. Molecular-dynamics simulations map out the pressure-temperature phase diagram of titanium
The contact angle in inviscid fluid mechanics
P N Shankar; R Kidambi
2005-08-17T23:59:59.000Z
We show that in general, the specification of a contact angle condition at the contact line in inviscid fluid motions is incompatible with the classical field equations and boundary conditions generally applicable to them. The limited conditions under which such a specification is permissible are derived; however, these include cases where the static meniscus is not flat. In view of this situation, the status of the many `solutions' in the literature which prescribe a contact angle in potential flows comes into question. We suggest that these solutions which attempt to incorporate a phenomenological, but incompatible, condition are in some, imprecise sense `weak-type solutions'; they satisfy or are likely to satisfy, at least in the limit, the governing equations and boundary conditions everywhere except in the neighbourhood of the contact line. We discuss the implications of the result for the analysis of inviscid flows with free surfaces.
Wide Angle Effects in Galaxy Surveys
Yoo, Jaiyul
2013-01-01T23:59:59.000Z
Current and future galaxy surveys cover a large fraction of the entire sky with a significant redshift range, and the recent theoretical development shows that general relativistic effects are present in galaxy clustering on very large scales. This trend has renewed interest in the wide angle effect in galaxy clustering measurements, in which the distant-observer approximation is often adopted. Using the full wide-angle formula for computing the redshift-space correlation function, we show that compared to the sample variance, the deviation in the redshift-space correlation function from the simple Kaiser formula with the distant-observer approximation is negligible in the SDSS and is completely irrelevant in future galaxy surveys such as Euclid and the BigBOSS, if the theoretical prediction from the Kaiser formula is averaged over the survey volume and the non-uniform distribution of cosine angle between the line-of-sight and the pair separation directions is properly considered. We also find small correctio...
Sugrue, Rosemary M
2012-01-01T23:59:59.000Z
The effects of orientation angle, subcooling, heat flux, mass flux, and pressure on bubble growth and detachment in subcooled flow boiling were studied using a high-speed video camera in conjunction with a two-phase flow ...
LHC luminosity upgrade with large Piwinski angle scheme: a recent look
Bhat, C.M.; /Fermilab; Zimmermann, f.; /CERN
2011-09-01T23:59:59.000Z
Luminosity upgrade at the LHC collider using longitudinally flat bunches in combination with the large crossing angle (large Piwinski angle scheme) is being studied with renewed interest in recent years. By design, the total beam-beam tune shift at the LHC is less than 0.015 for two interaction points together. But the 2010-11 3.5 TeV collider operation and dedicated studies indicated that the beam-beam tune shift is >0.015 per interaction point. In view of this development we have revisited the requirements for the Large Piwinski Angle scheme at the LHC. In this paper we present a new set of parameters and luminosity calculations for the desired upgrade by investigating: (1) current performance of the LHC injectors, (2) e-cloud issues on nearly flat bunches and (3) realistic beam particle distributions from longitudinal beam dynamics simulations. We also make some remarks on the needed upgrades on the LHC injector accelerators.
Method for high resolution magnetic resonance analysis using magic angle technique
Wind, Robert A.; Hu, Jian Zhi
2003-12-30T23:59:59.000Z
A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.
Hannay Angle: Yet Another Symmetry Protected Topological Order Parameter in Classical Mechanics
Kariyado, Toshikaze
2015-01-01T23:59:59.000Z
Topological way of thinking now goes beyond conventional solid materials, and topological characterization of classical mechanical systems governed by Newton's equation of motion begins to attract much attention. To have a deeper insight on physical meaning of topological numbers in mechanical systems, we demonstrate the use of the Hannay angle, a classical counterpart of the Berry phase, as a symmetry protected topological order parameter. We first derive the Hannay angle using a canonical transformation that maps the Newton's equation to the Schr\\"{o}dinger type equation. The Hannay angle is then used to characterize a simple spring-mass model topologically with a particular focus on the bulk-edge correspondence and new aspects of the symmetry in a classical system.
Method for high resolution magnetic resonance analysis using magic angle technique
Wind, Robert A.; Hu, Jian Zhi
2004-12-28T23:59:59.000Z
A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.
Aggregation, Coarsening, and Phase Transformation in ZnSNanoparticles...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Coarsening, and Phase Transformation in ZnS NanoparticlesStudied by Molecular Dynamics Simulations. Aggregation, Coarsening, and Phase Transformation in ZnS...
Modeling and numerical approximation of two-phase ...
2011-02-09T23:59:59.000Z
Feb 9, 2011 ... phase incompressible flows with matching or non-matching density. ... The interfacial dynamics of two-phase immiscible fluids have attracted.
Ponderomotive phase plate for transmission electron microscopes
Reed, Bryan W. (Livermore, CA)
2012-07-10T23:59:59.000Z
A ponderomotive phase plate system and method for controllably producing highly tunable phase contrast transfer functions in a transmission electron microscope (TEM) for high resolution and biological phase contrast imaging. The system and method includes a laser source and a beam transport system to produce a focused laser crossover as a phase plate, so that a ponderomotive potential of the focused laser crossover produces a scattering-angle-dependent phase shift in the electrons of the post-sample electron beam corresponding to a desired phase contrast transfer function.
Mira, another angle | Argonne Leadership Computing Facility
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article)41clothThe Bonneville PowerTariff Pages default SignEnergy4 3. EFFECTIVEMira, another angle Download original image Â«
Small Angle X-ray Scattering (SAXS) Laboratory Learning Experiences
Meagher, Mary
.A. & Svergun D.I. (1987). Structure Analysis by Small-Angle X-Ray and Neutron Scattering. NY: Plenum PressSmall Angle X-ray Scattering (SAXS) Laboratory Learning Experiences o - Use of small angle X-ray scattering instrumentation o - Programs that you will use SAXS (BRUKER AXS) PRIMUS (Konarev, Volkov, Koch
Medium energy pitch angle distribution during substorm injected electron clouds
Bergen, Universitetet i
Medium energy pitch angle distribution during substorm injected electron clouds A. AÂ° snes,1 J, N. Ã?stgaard, and M. Thomsen (2005), Medium energy pitch angle distribution during substorm injected to obtain pitch angle resolved electron distribution data for measurements at energies 10 eV to 47 keV. [3
Ye, Peng
A large class of symmetry-protected topological phases (SPT) in boson/spin systems have been recently predicted by the group cohomology theory. In this work, we consider bosonic SPT states at least with charge symmetry ...
Carlisle, Bruce Scott
1994-01-01T23:59:59.000Z
-phase flow models in small diameter flow channels. An initial series of real-time neutron radiography experiments were performed at the Texas A&M University System, Texas Engineering Experiment Station, Nuclear Science Center Reactor (NSCR) to determined...
Medina, M.; Zhu, D.
The main focus of this paper was to present data to advance the design of a previously developed thermally-enhanced structural insulated panel (SIP) that had been outfitted with phase change materials (PCMs) (Medina et al., 2008). To advance...
Impedance Scaling for Small Angle Transitions
Stupakov, G.; Bane, Karl; /SLAC; Zagorodnov, I.; /DESY; ,
2010-10-27T23:59:59.000Z
Based on the parabolic equation approach to Maxwell's equations we have derived scaling properties of the high frequency impedance/short bunch wakefields of structures. For the special case of small angle transitions we have shown the scaling properties are valid for all frequencies. Using these scaling properties one can greatly reduce the calculation time of the wakefield/impedance of long, small angle, beam pipe transitions, like one often finds in insertion regions of storage rings. We have tested the scaling with wakefield simulations of 2D and 3D models of such transitions, and found that the scaling works well. In modern ring-based light sources one often finds insertion devices having extremely small vertical apertures (on the order of millimeters) to allow for maximal undulator fields reaching the beam. Such insertion devices require that there be beam pipe transitions from these small apertures to the larger cross-sections (normally on the order of centimeters) found in the rest of the ring. The fact that there may be many such transitions, and that these transitions introduce beam pipe discontinuities very close to the beam path, means that their impedance will be large and, in fact, may dominate the impedance budget of the entire ring. To reduce their impact on impedance, the transitions are normally tapered gradually over a long distance. The accurate calculation of the impedance or wakefield of these long transitions, which are typically 3D objects (i.e. they do not have cylindrical symmetry), can be quite a challenging numerical task. In this report we present a method of obtaining the impedance of a long, small angle transition from the calculation of a scaled, shorter one. Normally, the actual calculation is obtained from a time domain simulation of the wakefield in the structure, where the impedance can be obtained by performing a Fourier transform. We shall see that the scaled calculation reduces the computer time and memory requirements significantly, especially for 3D problems, and can make the difference between being able to solve a problem or not. The method is based on the parabolic equation approach to solving Maxwell's equation developed in Refs. [1, 2].
The effect of knee separation and backrest angle on lumbar lordosis angle in various seated postures
Bolen, Bradley Kyle
1999-01-01T23:59:59.000Z
.08, 20.32, and 35.56 cm) and three different angles of backrest inclination (90, 105, and 120-deg). Descriptive statistics and one-way ANOVA were used to evaluate the results. Tukey's test was used to compare significant differences among means...
Dynamic Modes of Red Blood Cells in Oscillatory Shear Flow
Hiroshi Noguchi
2010-06-12T23:59:59.000Z
The dynamics of red blood cells (RBCs) in oscillatory shear flow was studied using differential equations of three variables: a shape parameter, the inclination angle $\\theta$, and phase angle $\\phi$ of the membrane rotation. In steady shear flow, three types of dynamics occur depending on the shear rate and viscosity ratio. i) tank-treading (TT): $\\phi$ rotates while the shape and $\\theta$ oscillate. ii) tumbling (TB): $\\theta$ rotates while the shape and $\\phi$ oscillate. iii) intermediate motion: both $\\phi$ and $\\theta$ rotate synchronously or intermittently. In oscillatory shear flow, RBCs show various dynamics based on these three motions. For a low shear frequency with zero mean shear rate, a limit-cycle oscillation occurs, based on the TT or TB rotation at a high or low shear amplitude, respectively. This TT-based oscillation well explains recent experiments. In the middle shear amplitude, RBCs show an intermittent or synchronized oscillation. As shear frequency increases, the vesicle oscillation becomes delayed with respect to the shear oscillation. At a high frequency, multiple limit-cycle oscillations coexist. For a high mean shear rate with small shear oscillation, the shape and $\\theta$ oscillate in the TT motion but only one attractor exists even at high shear frequencies. The measurement of these oscillatory modes is a promising tool for quantifying the viscoelasticity of RBCs and synthetic capsules.
Loh, Watson
alternative for the transportation of heavy crude oils. The lubricating effect of the aqueous film leads of such surfaces by crude oils through contact angle measurements in systems containing heavy oil/aqueous phase Elsevier B.V. All rights reserved. Keywords: Heavy oil; Asphaltenes; Naphthenic acids; Wettability; Oil
Structure and Dynamics of Colliding Plasma Jets
Ryutov, D.
Monoenergetic-proton radiographs of laser-generated, high-Mach-number plasma jets colliding at various angles shed light on the structures and dynamics of these collisions. The observations compare favorably with results ...
Self-tuning Fuzzy Control Method Based on the Trajectory Performance of the Phase Plane
Zhang, J.; Chen, Y.; Xiong, J.
2006-01-01T23:59:59.000Z
The phase plane is already an important method to design fuzzy control systems and analyze their stability. The concept of the real-time response trajectory characteristic vectors and angles between the real-time characteristic vectors on the phase...
Bai,M.; Ptitsyn, V.; Roser, T.
2008-10-01T23:59:59.000Z
To keep the spin tune in the spin depolarizing resonance free region is required for accelerating polarized protons to high energy. In RHIC, two snakes are located at the opposite side of each accelerator. They are configured to yield a spin tune of 1/2. Two pairs of spin rotators are located at either side of two detectors in each ring in RHIC to provide longitudinal polarization for the experiments. Since the spin rotation from vertical to longitudinal is localized between the two rotators, the spin rotators do not change the spin tune. However, due to the imperfection of the orbits around the snakes and rotators, the spin tune can be shifted. This note presents the impact of the horizontal orbital angle between the two snakes on the spin tune, as well as the effect of the vertical orbital angle between two rotators at either side of the collision point on the spin tune.
Rackley, Benton Tiburce
1950-01-01T23:59:59.000Z
Westinghouse Phase Angle Meter . . . 10 6. Schematic of a Standard Phase Angle Meter . 17 7. Schematic of Converted Phase Angle Meter . . 18 8. Meter As Normally Connected To Power Line . 20 9 . Laboratory Circuit 10. Laboratorv Set Up 21 22 11. 9raph... conditions on the important lines. The attendant could then know when given lines are approaching instability and precautions could be taken on loading. BIBLIOGRAPHY BOOKS 1. Westinghouse Electric and Manufacturing Company, Electrical Transmission...
Davis, H.T.; Scriven, L.E.
1991-07-01T23:59:59.000Z
A major program of university research, longer-ranged and more fundamental in approach than industrial research, into basic mechanisms of enhancing petroleum recovery and into underlying physics, chemistry, geology, applied mathematics, computation, and engineering science has been built at Minnesota. The original focus was surfactant-based chemical flooding, but the approach taken was sufficiently fundamental that the research, longer-ranged than industrial efforts, has become quite multidirectional. Topics discussed are volume controlled porosimetry; fluid distribution and transport in porous media at low wetting phase saturation; molecular dynamics of fluids in ultranarrow pores; molecular dynamics and molecular theory of wetting and adsorption; new numerical methods to handle initial and boundary conditions in immiscible displacement; electron microscopy of surfactant fluid microstructure; low cost system for animating liquid crystallites viewed with polarized light; surfaces of constant mean curvature with prescribed contact angle.
Kuramoto dynamics in Hamiltonian systems
Dirk Witthaut; Marc Timme
2013-05-08T23:59:59.000Z
The Kuramoto model constitutes a paradigmatic model for the dissipative collective dynamics of coupled oscillators, characterizing in particular the emergence of synchrony. Here we present a classical Hamiltonian (and thus conservative) system with 2N state variables that in its action-angle representation exactly yields Kuramoto dynamics on N-dimensional invariant manifolds. We show that the synchronization transition on a Kuramoto manifold emerges where the transverse Hamiltonian action dynamics becomes unstable. The uncovered Kuramoto dynamics in Hamiltonian systems thus distinctly links dissipative to conservative dynamics.
Dosimetric Comparison of Manual and Beam Angle Optimization of Gantry Angles in IMRT
Srivastava, Shiv P. [Department of Radiation Oncology, Reid Hospital and Health Care Services, Richmond, IN (United States); Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States); Das, Indra J., E-mail: idas@iupui.edu [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States); Kumar, Arvind [Department of Radiation Oncology, Reid Hospital and Health Care Services, Richmond, IN (United States); Johnstone, Peter A.S. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States)
2011-10-01T23:59:59.000Z
Dosimetric comparison of manual beam angle selection (MBS) and beam angle optimization (BAO) for IMRT plans is investigated retrospectively for 15 head and neck and prostate patients. The head and neck and prostate had planning target volumes (PTVs) ranging between 96.0 and 319.9 cm{sup 3} and 153.6 and 321.3 cm{sup 3}, whereas OAR ranged between 8.3 and 47.8 cm{sup 3} and 68.3 and 469.2 cm{sup 3}, respectively. In MBS, a standard coplanar 7-9 fields equally spaced gantry angles were used. In BAO, the selection of gantry angle was optimized by the algorithm for the same number of beams. The optimization and dose-volume constraints were kept the same for both techniques. Treatment planning was performed on the Eclipse treatment planning system. Our results showed that the dose-volume histogram for PTV are nearly identical in both techniques but BAO provided superior sparing of the organs at risk compared with the MBS. Also, MBS produced statistically significant higher monitor units (MU) and segments than the BAO; 13.1 {+-} 6.6% (p = 0.012) and 10.4 {+-} 13.6% (p = 0.140), and 14.6 {+-} 5.6% (p = 1.003E-5) and 12.6 {+-} 7.4% (p = 0.76E-3) for head and neck and prostate cases, respectively. The reduction in MU translates into the reduction in total body and integral dose. It is concluded that BAO provides advantage over MBS for most intenisty-modulated radiation therapy cases.
Eduardo del Pozo Garcia
2015-02-25T23:59:59.000Z
An Alternative to explain the origin of matter-background connections from the paper "Do Cosmic Backgrounds Cyclical Renew by Matter and Quanta Emissions?..." proposed: A sequence of discontinuous small changes of light speed in time as the cause, which provoke that criticality processes take place every 26-30 million years. Then, matter particles and quanta reach at one threshold value, and are compelled to reorganize their internal energy and make emissions that later becomes in current cosmic backgrounds. The small discontinues relative decreasing of c of about 10 -5) should do some small effects on planet and living bodies. Cyclic small reorganization of matter particles is consider as the astrophysical origin of Earth cyclic catastrophes. And at space global distribution: quantized redshift, change of galaxy fractal distribution at 10 Mpc scale, galaxy average luminosity and the luminosity fluctuation of galaxy pairs are enhanced out to separations near 10 Mpc. Also proposed: Like the Universe is observed flat in distance and time, the gravitational constant G might decrease with time, which may originate the Earth orbit eccentricity cycle of 100000 yr and, provoke the former mentioned sequence of c decrease in time. And, every 6 million years, the accumulation of G relative decrease of about 10-5 in G compelled space-time to reach at one threshold value that, trigger small relative decrease of light speed c of about 10-5 cyclically. This is interpreted as the Universe has two dynamical phases following one each other cyclically with intervals of 26-30 million years respectively: One of about 0.1 million years, called "activation phase", at which the critical processes take place, follows by longer "inhibition phase". The present approach indicates the existence of a subtle non linear dynamics, which could also contribute to the origin of galaxy fractal distribution.
The Role of Contact Angle Hysteresis for Fluid Transport in Wet Granular Matter
Roman Mani; Ciro Semprebon; Dirk Kadau; Hans J. Herrmann; Martin Brinkmann; Stephan Herminghaus
2015-08-06T23:59:59.000Z
The stability of sand castles is determined by the structure of wet granulates. Experimental data about the size distribution of fluid pockets are ambiguous about their origin. We discovered that contact angle hysteresis plays a fundamental role in the equilibrium distribution of bridge volumes, and not geometrical disorder as commonly conjectured, which has substantial consequences on the mechanical properties of wet granular beds, including a history dependent rheology and lowered strength. Our findings are obtained using a novel model where the Laplace pressures, bridge volumes and contact angles are dynamical variables associated to the contact points. While accounting for contact line pinning, we track the temporal evolution of each bridge. We observe a cross-over to a power-law decay of the variance of capillary pressures at late times and a saturation of the variance of bridge volumes to a finite value connected to contact line pinning. Large scale simulations of liquid transport in the bridge network reveal that the equilibration dynamics at early times is well described by a mean field model. The spread of final bridge volumes can be directly related to the magnitude of contact angle hysteresis.
Emission angle distribution and flavor transformation of supernova neutrinos
Wei Liao
2009-06-28T23:59:59.000Z
Using moment equations we analyze collective flavor transformation of supernova neutrinos. We study the convergence of moment equations and find that numerical results using a few moment converge quite fast. We study effects of emission angle distribution of neutrinos on neutrino sphere. We study scaling law of the amplitude of neutrino self-interaction Hamiltonian and find that it depends on model of emission angle distribution of neutrinos. Dependence of neutrino oscillation on different models of emission angle distribution is studied.
Geometric Phase and Classical-Quantum Correspondence
Indubala I. Satija; Radha Balakrishnan
2004-03-05T23:59:59.000Z
We study the geometric phase factors underlying the classical and the corresponding quantum dynamics of a driven nonlinear oscillator exhibiting chaotic dynamics. For the classical problem, we compute the geometric phase factors associated with the phase space trajectories using Frenet-Serret formulation. For the corresponding quantum problem, the geometric phase associated with the time evolution of the wave function is computed. Our studies suggest that the classical geometric phase may be related to the the difference in the quantum geometric phases between two neighboring eigenstates.
The generalized Mackenzie distribution: disorientation angle distributions for arbitrary textures
Mason, J. K.
A general formulation for the disorientation angle distribution function is derived. The derivation employs the hyperspherical harmonic expansion for orientation distributions, and an explicit solution is presented for ...
Identification of high angle structures controlling the geothermal...
Rye Patch, Nevada Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Identification of high angle structures controlling the geothermal system at...
ANGLE-RESOLVED PHOTOEMISSION STUDIES OF Ag, Au, AND Pt
Davis, R.F.
2010-01-01T23:59:59.000Z
under Contract W-7405-ENG-48 ANGLE-RESOLVED PHOTOEMISSIONEnergy under Contract No. W-7405-Eng-48. It was performed at
Measurements of integral muon intensity at large zenith angles
A. N. Dmitrieva; D. V. Chernov; R. P. Kokoulin; K. G. Kompaniets; G. Mannocchi; A. A. Petrukhin; O. Saavedra; V. V. Shutenko; D. A. Timashkov; G. Trinchero; I. I. Yashin
2006-11-28T23:59:59.000Z
High-statistics data on near-horizontal muons collected with Russian-Italian coordinate detector DECOR are analyzed. Precise measurements of muon angular distributions in zenith angle interval from 60 to 90 degrees have been performed. In total, more than 20 million muons are selected. Dependences of the absolute integral muon intensity on zenith angle for several threshold energies ranging from 1.7 GeV to 7.2 GeV are derived. Results for this region of zenith angles and threshold energies have been obtained for the first time. The dependence of integral intensity on zenith angle and threshold energy is well fitted by a simple analytical formula.
SURFACE CHARACTERIZATION OF CHEMICALLY MODIFIED WOOD: DYNAMIC WETTABILITY1
wetting slope and K value) were used to illustrate the dynamic wetting process. Dynamic contact angle the dynamic wettability of wood surfaces modified with different coupling agents. Keywords: Chemical articles on dynamic wetting process for wood adhesion have been published (Scheikl and Dunky 1998
Supercooling and phase coexistence in cosmological phase transitions
Megevand, Ariel; Sanchez, Alejandro D. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Dean Funes 3350, (7600) Mar del Plata (Argentina)
2008-03-15T23:59:59.000Z
Cosmological phase transitions are predicted by particle physics models, and have a variety of important cosmological consequences, which depend strongly on the dynamics of the transition. In this work we investigate in detail the general features of the development of a first-order phase transition. We find thermodynamical constraints on some quantities that determine the dynamics, namely, the latent heat, the radiation energy density, and the false-vacuum energy density. Using a simple model with a Higgs field, we study numerically the amount and duration of supercooling and the subsequent reheating and phase coexistence. We analyze the dependence of the dynamics on the different parameters of the model, namely, the energy scale, the number of degrees of freedom, and the couplings of the scalar field with bosons and fermions. We also inspect the implications for the cosmological outcomes of the phase transition.
Measurement of the analysing power in proton-proton elastic scattering at small angles
Z. Bagdasarian; D. Chiladze; S. Dymov; A. Kacharava; G. Macharashvili; S. Barsov; R. Gebel; B. Gou; M. Hartmann; I. Keshelashvili; A. Khoukaz; P. Kulessa; A. Kulikov; A. Lehrach; N. Lomidze; B. Lorentz; R. Maier; D. Mchedlishvili; S. Merzliakov; S. Mikirtychyants; M. Nioradze; H. Ohm; M. Papenbrock; D. Prasuhn; F. Rathmann; V. Serdyuk; V. Shmakova; R. Stassen; H. Stockhorst; I. I. Strakovsky; H. Ströher; M. Tabidze; A. Täschner; S. Trusov; D. Tsirkov; Yu. Uzikov; Yu. Valdau; C. Wilkin; R. L. Workman
2014-10-28T23:59:59.000Z
The proton analysing power in $\\vec{p}p$ elastic scattering has been measured at small angles at COSY-ANKE at 796 MeV and five other beam energies between 1.6 and 2.4 GeV using a polarised proton beam. The asymmetries obtained by detecting the fast proton in the ANKE forward detector or the slow recoil proton in a silicon tracking telescope are completely consistent. Although the analysing power results agree well with the many published data at 796 MeV, and also with the most recent partial wave solution at this energy, the ANKE data at the higher energies lie well above the predictions of this solution at small angles. An updated phase shift analysis that uses the ANKE results together with the World data leads to a much better description of these new measurements.
Konstantine Zelator
2012-08-01T23:59:59.000Z
Let ABC be a triangle with a,b,and c being its three sidelengths. In a 1976 article by Wynne William Wilson in the Mathematical Gazette(see reference[2]), the author showed that angleB is twice angleA, if and only if b^2=a(a+c). We offer our own proof of this result in Proposition1.Using Proposition1 and Lemma2, we establish Proposition 2: Let a,b,c be positive reals. Then a triangle ABC having a,b,c as its sidelengths can be formed if,and onlyif, b^2=a(a+c) and either cintegral triangles, that is; a,b, and c bieng positive integers.In 2002, in a paper published in the Mathematical Gazette(see[2]), author M.N.Deshpande provided two-parameter formulas that describe some integral triangles with (angle)B=2(angle)A. In Result2 in Section5, we offer 3-parameter formulas that describe the entire family of integral triangles ABC with angleA=2angleB. Using Result1, we then parametrically describe the entire family of integral triangles with angle A=2angleB; and with the bisector of angleB also of integral length. This is done in Reult2 in Section6. In Section7, we conclude this article with two closing remarks.
Steiner Minimal Trees, Twist Angles, and the Protein Folding Problem
Smith, J. MacGregor
Steiner Minimal Trees, Twist Angles, and the Protein Folding Problem J. MacGregor Smith, Yunho Jang. These properties should be ultimately useful in the ab ini- tio protein folding prediction. Proteins 2007;66:889 902. VVC 2006 Wiley-Liss, Inc. Key words: Steiner trees; twist angles; protein fold- ing; side chain
Delayed Afterglow Onset Interpreted as Baryon-Poor Viewing Angle
David Eichler
2005-03-24T23:59:59.000Z
We have suggested previously that baryons in GRB fireballs infiltrate from the surrounding walls that collimate the fireball. The efficiency $\\epsilon_b$ for generating blast energy can then be angle dependent. Delayed onset of afterglow can be interpreted as being due to a baryon-poor viewing angle.
Dwaipayan Chakrabarti; Biman Bagchi
2006-05-29T23:59:59.000Z
We find in a model system of thermotropic liquid crystals that the translational diffusion coefficient parallel to the director $D_{\\parallel}$ first increases and then decreases as temperature drops through the nematic phase, and this reversal occurs where the smectic order parameter of the underlying inherent structures becomes significant for the first time. We argue, based on an energy landscape analysis, that the coupling between orientational and translational order can play a role in inducing the non-monotonic temperature behavior of $D_{\\parallel}$. Such a view is likely to form the foundation of a theoretical framework to explain the anisotropic translation diffusion.
Kennedy, John M.; Kim, Sunwoo; Kim, Kwang J.
2009-10-06T23:59:59.000Z
Phase change heat transfer is notorious for increasing the irreversibility of, and therefore decreasing the efficiency of, geothermal power plants. Its significant contribution to the overall irreversibility of the plant makes it the most important source of inefficiency in the process. Recent studies here have shown the promotion of drop wise condensation in the lab by means of increasing the surface energy density of a tube with nanotechnology. The use of nanotechnology has allowed the creation of surface treatments which discourage water from wetting a tube surface during a static test. These surface treatments are unique in that they create high- contact angles on the condensing tube surfaces to promote drop wise condensation.
Neutrino Mixing Angles from Texture Zeros of the Lepton Mass Matrices
Fritzsch, Harald
2012-01-01T23:59:59.000Z
Taking into account the latest neutrino oscillation data, we study texture zeros of the lepton mass matrices. Assuming the Dirac neutrino mass matrix M_D, the charged-lepton mass matrix M_l and the mass matrix of heavy right-handed Majorana neutrinos M_R to have three texture zeros, we show that the observed neutrino mixing angles can naturally be obtained. The phenomenological implications for the neutrino mass spectrum, the CP-violating phases, the tritium beta decay and the neutrinoless double-beta decay are explored.
Neutrino Mixing Angles from Texture Zeros of the Lepton Mass Matrices
Harald Fritzsch; Shun Zhou
2012-12-03T23:59:59.000Z
Taking into account the latest neutrino oscillation data, we study texture zeros of the lepton mass matrices. Assuming the Dirac neutrino mass matrix M_D, the charged-lepton mass matrix M_l and the mass matrix of heavy right-handed Majorana neutrinos M_R to have three texture zeros, we show that the observed neutrino mixing angles can naturally be obtained. The phenomenological implications for the neutrino mass spectrum, the CP-violating phases, the tritium beta decay and the neutrinoless double-beta decay are explored.
Shape Dynamics. An Introduction
Julian Barbour
2011-05-01T23:59:59.000Z
Shape dynamics is a completely background-independent universal framework of dynamical theories from which all absolute elements have been eliminated. For particles, only the variables that describe the shapes of the instantaneous particle configurations are dynamical. In the case of Riemannian three-geometries, the only dynamical variables are the parts of the metric that determine angles. The local scale factor plays no role. This leads to a shape-dynamic theory of gravity in which the four-dimensional diffeomorphism invariance of general relativity is replaced by three-dimensional diffeomorphism invariance and three-dimensional conformal invariance. Despite this difference of symmetry groups, it is remarkable that the predictions of the two theories -- shape dynamics and general relativity -- agree on spacetime foliations by hypersurfaces of constant mean extrinsic curvature. However, the two theories are distinct, with shape dynamics having a much more restrictive set of solutions. There are indications that the symmetry group of shape dynamics makes it more amenable to quantization and thus to the creation of quantum gravity. This introduction presents in simple terms the arguments for shape dynamics, its implementation techniques, and a survey of existing results.
Rekik, Najeh; Freedman, Holly; Hanna, Gabriel [Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2 (Canada); Hsieh, Chang-Yu [Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6 (Canada)
2013-04-14T23:59:59.000Z
We apply two approximate solutions of the quantum-classical Liouville equation (QCLE) in the mapping representation to the simulation of the laser-induced response of a quantum subsystem coupled to a classical environment. These solutions, known as the Poisson Bracket Mapping Equation (PBME) and the Forward-Backward (FB) trajectory solutions, involve simple algorithms in which the dynamics of both the quantum and classical degrees of freedom are described in terms of continuous variables, as opposed to standard surface-hopping solutions in which the classical degrees of freedom hop between potential energy surfaces dictated by the discrete adiabatic state of the quantum subsystem. The validity of these QCLE-based solutions is tested on a non-trivial electron transfer model involving more than two quantum states, a time-dependent Hamiltonian, strong subsystem-bath coupling, and an initial energy shift between the donor and acceptor states that depends on the strength of the subsystem-bath coupling. In particular, we calculate the time-dependent population of the photoexcited donor state in response to an ultrafast, on-resonance pump pulse in a three-state model of an electron transfer complex that is coupled asymmetrically to a bath of harmonic oscillators through the optically dark acceptor state. Within this approach, the three-state electron transfer complex is treated quantum mechanically, while the bath oscillators are treated classically. When compared to the more accurate QCLE-based surface-hopping solution and to the numerically exact quantum results, we find that the PBME solution is not capable of qualitatively capturing the population dynamics, whereas the FB solution is. However, when the subsystem-bath coupling is decreased (which also decreases the initial energy shift between the donor and acceptor states) or the initial shift is removed altogether, both the PBME and FB results agree better with the QCLE-based surface-hopping results. These findings highlight the challenges posed by various conditions such as a time-dependent external field, the strength of the subsystem-bath coupling, and the degree of asymmetry on the accuracy of the PBME and FB algorithms.
From a Single-Band Metal to a High-Temperature Superconductor via Two Thermal Phase Transitions
He, R.-H.; Hashimoto, M.; Karapetyan, H.; Koralek, J.D.; Hinton, J.P.; Testaud, J.P.; Nathan, V.; Yoshida, Y.; Yao, H.; Tanaka, K.; Meevasana, W.; Moore, R.G.; Lu, D.H.; Mo, S.-K.; Ishikado, M.; Eisaki, H.; Hussain, Z.; Devereaux, T.P.; Kivelson, S.A.; Orenstein, J.; Kapitulnik, A.
2011-11-08T23:59:59.000Z
The nature of the pseudogap phase of cuprate high-temperature superconductors is one of the most important unsolved problems in condensed matter physics. We studied the commencement of the pseudogap state at temperature T* using three different techniques (angle-resolved photoemission spectroscopy, polar Kerr effect, and time-resolved reflectivity) on the same optimally-doped Bi2201 crystals. We observe the coincident onset at T* of a particle-hole asymmetric antinodal gap, a non-zero Kerr rotation, and a change in the relaxational dynamics, consistent with a phase transition. Upon further cooling, spectroscopic signatures of superconductivity begin to grow close to the superconducting transition temperature (T{sub c}), entangled in an energy-momentum dependent fashion with the pre-existing pseudogap features.
SU-E-I-56: Scan Angle Reduction for a Limited-Angle Intrafraction Verification (LIVE) System
Ren, L; Zhang, Y; Yin, F [Duke University Medical Center, Durham, NC (United States)
2014-06-01T23:59:59.000Z
Purpose: To develop a novel adaptive reconstruction strategy to further reduce the scanning angle required by the limited-angle intrafraction verification (LIVE) system for intrafraction verification. Methods: LIVE acquires limited angle MV projections from the exit fluence of the arc treatment beam or during gantry rotation between static beams. Orthogonal limited-angle kV projections are also acquired simultaneously to provide additional information. LIVE considers the on-board 4D-CBCT images as a deformation of the prior 4D-CT images, and solves the deformation field based on deformation models and data fidelity constraint. LIVE reaches a checkpoint after a limited-angle scan, and reconstructs 4D-CBCT for intrafraction verification at the checkpoint. In adaptive reconstruction strategy, a larger scanning angle of 30° is used for the first checkpoint, and smaller scanning angles of 15° are used for subsequent checkpoints. The onboard images reconstructed at the previous adjacent checkpoint are used as the prior images for reconstruction at the current checkpoint. As the algorithm only needs to reconstruct the small deformation occurred between adjacent checkpoints, projections from a smaller scan angle provide enough information for the reconstruction. XCAT was used to simulate tumor motion baseline drift of 2mm along sup-inf direction at every subsequent checkpoint, which are 15° apart. Adaptive reconstruction strategy was used to reconstruct the images at each checkpoint using orthogonal 15° kV and MV projections. Results: Results showed that LIVE reconstructed the tumor volumes accurately using orthogonal 15° kV-MV projections. Volume percentage differences (VPDs) were within 5% and center of mass shifts (COMS) were within 1mm for reconstruction at all checkpoints. Conclusion: It's feasible to use an adaptive reconstruction strategy to further reduce the scan angle needed by LIVE to allow faster and more frequent intrafraction verification to minimize the treatment errors in lung cancer treatments. Grant from Varian Medical System.
High Temperature, Large Sample Volume, Constant Flow Magic Angle...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
High Temperature, Large Sample Volume, Constant Flow Magic Angle Spinning NMR Probe for a 11.7 T Magnetic Field for In Situ Catalytic Reaction Characterization Project start date:...
Modelling contact angle hysteresis on chemically patterned and superhydrophobic surfaces
H. Kusumaatmaja; J. M. Yeomans
2006-11-03T23:59:59.000Z
We investigate contact angle hysteresis on chemically patterned and superhydrophobic surfaces, as the drop volume is quasi-statically increased and decreased. We consider both two, and three, dimensions using analytical and numerical approaches to minimise the free energy of the drop. In two dimensions we find, in agreement with other authors, a slip, jump, stick motion of the contact line. In three dimensions this behaviour persists, but the position and magnitude of the contact line jumps are sensitive to the details of the surface patterning. In two dimensions we identify analytically the advancing and receding contact angles on the different surfaces and we use numerical insights to argue that these provide bounds for the three dimensional cases. We present explicit simulations to show that a simple average over the disorder is not sufficient to predict the details of the contact angle hysteresis, and to support an explanation for the low contact angle hysteresis of suspended drops on superhydrophobic surfaces.
Contact angle hysteresis: a review of fundamentals and applications
’t Mannetje, D. J. C. M.
Contact angle hysteresis is an important physical phenomenon. It is omnipresent in nature and also plays a crucial role in various industrial processes. Despite its relevance, there is a lack of consensus on how to incorporate ...
Boundary layer modeling of reactive flow over a porous surface with angled injection
Liu, Shiling; Fotache, Catalin G.; Hautman, Donald J.; Ochs, Stuart S. [United Technologies Research Center, MS 129-29, 411 Silver Lane, East Hartford, CT 06108 (United States); Chao, Beei-Huan [Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)
2008-08-15T23:59:59.000Z
An analytical model was developed to investigate the dynamics of nonpremixed flames in a shear layer established between a mainstream flow of fuel-rich combustion products and a porous surface with an angled injection of air. In the model, a one-step overall chemical reaction was employed, together with boundary layer conservation equations solved using similarity solutions. Parametric studies were performed to understand the effects of equivalence ratio, temperature, and mass flow rate of the fuel and air streams on the flame standoff distance, surface temperature, and heat flux at the surface. The analytical model predictions were compared with computational fluid dynamics results obtained using the FLUENT commercial code for both the laminar and the turbulent flow models. Qualitative agreement in surface temperature was observed. Finally, the flame stability limits predicted by the model were compared with available experimental data and found to agree qualitatively, as well. (author)
Jeremy Causse; Julian Oberdisse; Jacques Jestin; Serge Lagerge
2010-12-04T23:59:59.000Z
We have studied the solubilization behaviour of tributylphosphate (TBP) in aqueous solutions of L64-Pluronics, using light and small angle neutron scattering (SANS). Varying the temperature and the oil-content, the system presents a non trivial phase behaviour. In particular, at 308K, a first solubilization followed by an emulsification failure and a resolubilization is found. We have measured the microstructure by SANS and characterized the microemulsion droplet core-size, corona-thickness, polydispersity, and interactions. It is shown that at low oil content, the system is made of small swollen micelles. After the phase separation, the resolubilization is carried by larger oil droplets decorated by copolymer. From specific surface measurements at large angles, a surprising change in surfactant conformation is found to accompany this morphological evolution which is also supported by previous results obtained from 1H NMR experiments. In independent measurements, our structural modelling is confirmed using contrast-variation SANS.
W. Li; S. Zhang; Y. G. Ma; X. Z. Cai; J. H. Chen; H. Z. Huang; G. L. Ma; C. Zhong
2010-01-07T23:59:59.000Z
Dihadron azimuthal angle correlations relative to the reaction plane have been investigated in Au + Au collisions at $\\sqrt{s_{NN}}$ = 200 GeV using a multi-phase transport model (AMPT). Such reaction plane azimuthal angle dependent correlations can shed light on path-length effect of energy loss of high transverse momentum particles propagating through the hot dense medium. The correlations vary with the trigger particle azimuthal angle with respect to the reaction plane direction, $\\phi_{s}=\\phi_{T}-\\Psi_{EP}$, which is consistent with the experimental observation by the STAR collaboration. The dihadron azimuthal angle correlation functions on the away side of the trigger particle present a distinct evolution from a single peak to a broad, possibly double peak, structure when the trigger particle direction goes from in-plane to out-of-plane of the reaction plane. The away-side angular correlation functions are asymmetric with respect to the back-to-back direction in some regions of $\\phi_{s}$, which could provide insight on testing $v_{1}$ method to reconstruct the reaction plane. In addition, both the root-mean-square width ($W_{rms}$) of the away-side correlation distribution and the splitting parameter $D$ between the away-side double peaks increase slightly with $\\phi_{s}$, and the average transverse momentum of the away-side associated hadrons shows a strong $\\phi_{s}$ dependence. Our results indicate that strong parton cascade and resultant energy loss could play an important role for the appearance of a double-peak structure in the dihadron azimuthal angular correlation function on the away side of the trigger particle.
Accepted Manuscript Using Small Angle Solution Scattering Data in Xplor-NIH Structure Calcula-
Clore, G. Marius
and wide angle X-ray and small angle neutron scattering for biomolecular structure calculation using and wide angle X-ray scattering (SAXS/WAXS) and small angle neutron scattering (SANS) data, on the otherAccepted Manuscript Using Small Angle Solution Scattering Data in Xplor-NIH Structure Calcula
Angle-resolved photoemission spectroscopy (ARPES) studies of cuprate superconductors
Palczewski, Ari Deibert
2010-12-15T23:59:59.000Z
This dissertation is comprised of three different angle-resolved photoemission spectroscopy (ARPES) studies on cuprate superconductors. The first study compares the band structure from two different single layer cuprates Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}} (Tl2201) T{sub c,max} {approx} 95 K and (Bi{sub 1.35}Pb{sub 0.85})(Sr{sub 1.47}La{sub 0.38})CuO{sub 6+{delta}} (Bi2201) T{sub c,max} {approx} 35 K. The aim of the study was to provide some insight into the reasons why single layer cuprate's maximum transition temperatures are so different. The study found two major differences in the band structure. First, the Fermi surface segments close to ({pi},0) are more parallel in Tl2201 than in Bi2201. Second, the shadow band usually related to crystal structure is only present in Bi2201, but absent in higher T{sub c} Tl2201. The second study looks at the different ways of doping Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi2212) in-situ by only changing the post bake-out vacuum conditions and temperature. The aim of the study is to systematically look into the generally overlooked experimental conditions that change the doping of a cleaved sample in ultra high vacuum (UHV) experiments. The study found two major experimental facts. First, in inadequate UHV conditions the carrier concentration of Bi2212 increases with time, due to the absorption of oxygen from CO{sub 2}/CO molecules, prime contaminants present in UHV systems. Second, in a very clean UHV system at elevated temperatures (above about 200 K), the carrier concentration decreases due to the loss of oxygen atoms from the Bi-O layer. The final study probed the particle-hole symmetry of the pseudogap phase in high temperature superconducting cuprates by looking at the thermally excited bands above the Fermi level. The data showed a particle-hole symmetric pseudogap which symmetrically closes away from the nested FS before the node. The data is consistent with a charge density wave (CDW) origin of the pseudogap, similar to STM checkerboard patterns in the pseudogap state.
Ying, D.H.S.; Sivasubramanian, R.; Moujaes, S.F.; Givens, E.N.
1982-04-01T23:59:59.000Z
A commercial coal liquefaction plant will employ vertical tubular reactors feeding slurry and gas concurrently upward through these vessels. In the SRC-I plant design the reactor is essentially an empty vessel with only a distributor plate located near the inlet. Because the commercial plant represents a considerable scale-up over Wilsonville or any pilot plant, this program addressed the need for additional data on behavior of three phase systems in large vessels. Parameters that were investigated in this program were studied at conditions that relate directly to projected plant operating conditions. The fluid dynamic behavior of the three-phase upflow system was studied by measuring gas and slurry holdup, liquid dispersion, solids suspension and solids accumulation. The dependent parameters are gas and liquid velocities, solid particle size, solids concentration, liquid viscosity, liquid surface tension and inlet distributor. Within the range of liquid superficial velocity from 0.0 to 0.5 ft/sec, gas holdup is found to be independent of liquid flow which agrees with other investigators. The results also confirm our previous finding that gas holdup is independent of column diameter when the column diameter is 5 inches or larger. The gas holdup depends strongly on gas flow rate; gas holdup increases with increasing gas velocity. The effect of solids particles on gas holdup depends on the gas flow rate. Increasing liquid viscosity and surface tension reduce gas holdup which agrees with other investigators. Because of the complexity of the system, we could not find a single correlation to best fit all the data. The degree of liquid backmixing markedly affects chemical changes occurring in the dissolver, such as sulfur removal, and oil and distillate formation.
Fermion Path Integrals And Topological Phases
Witten, Edward
2015-01-01T23:59:59.000Z
Symmetry-protected topological (SPT) phases of matter have been interpreted in terms of anomalies, and it has been expected that a similar picture should hold for SPT phases with fermions. Here, we describe in detail what this picture means for phases of quantum matter that can be understood via band theory and free fermions. The main examples we consider are time-reversal invariant topological insulators and superconductors in 2 or 3 space dimensions. Along the way, we clarify the precise meaning of the statement that in the bulk of a 3d topological insulator, the electromagnetic $\\theta$-angle is equal to $\\pi$.
Geometric Phase in a Bose-Einstein Josephson Junction
Radha Balakrishnan; Mitaxi Mehta
2003-07-04T23:59:59.000Z
We calculate the geometric phase associated with the time evolution of the wave function of a Bose-Einstein condensate system in a double-well trap by using a model for tunneling between the wells. For a cyclic evolution, this phase is shown to be half the solid angle subtended by the evolution of a unit vector whose z component and azimuthal angle are given by the population difference and phase difference between the two condensates. For a non-cyclic evolution an additional phase term arises. We show that the geometric phase can also be obtained by mapping the tunneling equations onto the equations os a space curve. The importance of a geometric phase in the context of some recent experiments is pointed out.
Nonlinear Adaptive Dynamic Inversion Control for Hypersonic Vehicles
Rollins, Elizabeth
2013-09-03T23:59:59.000Z
-of-attack and sideslip angle. To prevent undesirable inlet unstart events, the nonlinear adaptive dynamic inversion control architecture is given the ability to enforce state constraints. Because several phenomena can cause inlet unstarts, the control architecture also...
How ARCO drills high-angle wells offshore Indonesia
Tjondrodiputro, B.; Eddyarso, H.; Jones, K. (Atlantic Richfield Indonesia, Inc., Jakarta (Indonesia))
1993-03-01T23:59:59.000Z
Atlantic Richfield Indonesia, Inc. (ARII) drilled and completed 28 high-angle wells since early 1986 in Bima, Papa and FF fields in the Offshore North West Java Sea (ONWJ) contract area. Early wells were drilled with conventional rotary bottomhole assemblies (BHAs); introduction of a steerable tool and MWD subsequently increased efficiency and reduced drilling costs. Both lignosulfonate and dispersed pac polymer muds have been used with good success. Cost to drill a high-angle well has been only marginally more than that of a 45[degree] directional well. Elimination of open hole logging and use of preperforated liners have reduced drilling costs by 10%. Production performance for wells has been higher than for vertical or low-angle wells. High-angle wells in Bima have outperformed offset vertical wells and are classified as a success. However, horizontal wells in Papa, which has a strong bottom-water drive, have not shown any improved recovery over conventional wells. The new well in FF field is still being evaluated. In this first of a two-part report, high-angle drilling operations including well planning, BHA selection, casing and mud programs, hole cleaning and logging are described. Specific wells in the Bima area are discussed as examples.
Collective phase description of oscillatory convection
Kawamura, Yoji, E-mail: ykawamura@jamstec.go.jp [Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001 (Japan)] [Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001 (Japan); Nakao, Hiroya [Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology, Tokyo 152-8552 (Japan)] [Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology, Tokyo 152-8552 (Japan)
2013-12-15T23:59:59.000Z
We formulate a theory for the collective phase description of oscillatory convection in Hele-Shaw cells. It enables us to describe the dynamics of the oscillatory convection by a single degree of freedom which we call the collective phase. The theory can be considered as a phase reduction method for limit-cycle solutions in infinite-dimensional dynamical systems, namely, stable time-periodic solutions to partial differential equations, representing the oscillatory convection. We derive the phase sensitivity function, which quantifies the phase response of the oscillatory convection to weak perturbations applied at each spatial point, and analyze the phase synchronization between two weakly coupled Hele-Shaw cells exhibiting oscillatory convection on the basis of the derived phase equations.
Physical region for three-neutrino mixing angles
D. C. Latimer; D. J. Ernst
2004-10-11T23:59:59.000Z
We derive a set of symmetry relations for the three-neutrino mixing angles, including the MSW matter effect. Though interesting in their own right, these relations are used to choose the physical region of the mixing angles such that oscillations are parameterized completely and uniquely. We propose that the preferred way of setting the bounds on the mixing angles should be $\\theta_{12} \\in [0,\\pi/2]$, $\\theta_{13} \\in [-\\pi/2,\\pi/2]$, $\\theta_{23}\\in [0,\\pi/2]$, and $\\delta \\in [0,\\pi)$. No CP violation then results simply from setting $\\delta=0$. In the presence of the MSW effect, this choice of bounds is a new result. Since the size of the asymmetry about $\\theta_{13} = 0$ is dependent on the details of the data analysis and is a part of the results of the analysis, we argue that the negative values of $\\theta_{13}$ should not be ignored.
Opening angles and shapes of parsec-scale AGN jets
Pushkarev, Alexander B; Kovalev, Yuri Y; Savolainen, Tuomas
2015-01-01T23:59:59.000Z
We used 15 GHz VLBA observations of 366 sources having at least 5 epochs within a time interval 1995-2013 from the MOJAVE program and/or its predecessor, the 2 cm VLBA Survey. For each source we produced a corresponding stacked image averaging all available epochs for a better reconstruction of the cross section of the flow. We have analyzed jet profiles transverse to the local jet ridge line and derived both apparent and intrinsic opening angles of the parsec-scale outflows. The sources detected by the Fermi Large Area Telescope (LAT) during the first 24 months of operation show wider apparent jet opening angle and smaller viewing angles on a very high level of significance supporting our early findings. Analyzing transverse shapes of the outflows we found that most sources have conical jet geometry at parsec scales, though there are also sources that exhibit active jet collimation.
Anholonomy and Geometrical Localization in Dynamical Systems
Radha Balakrishnan; Indubala Satija
2003-03-31T23:59:59.000Z
We characterize the geometrical and topological aspects of a dynamical system by associating a geometric phase with a phase space trajectory. Using the example of a nonlinear driven damped oscillator, we show that this phase is resilient to fluctuations, responds to all bifurcations in the system, and also finds new geometric transitions. Enriching the phase space description is a novel phenomenon of ``geometrical localization'' which manifests itself as a significant deviation from planar dynamics over a short time interval.
Cerchiai, Bianca L; Bertini, S.; Cacciatori, Sergio L.
2005-10-20T23:59:59.000Z
In this paper we reconsider the problem of the Euler parametrization for the unitary groups. After constructing the generic group element in terms of generalized angles, we compute the invariant measure on SU(N) and then we determine the full range of the parameters, using both topological and geometrical methods. In particular, we show that the given parametrization realizes the group SU(N+1) as a fibration of U(N) over the complex projective space CP{sup n}. This justifies the interpretation of the parameters as generalized Euler angles.
2002-01-01T23:59:59.000Z
by using small angle neutron scattering Winnie Yong †‡ ,technique of small angle neutron scattering has been used tois small angle neutron scattering (SANS). SANS experiments
TIME-RESOLVED PHOTOMETRY OF KUIPER BELT OBJECTS: ROTATIONS, SHAPES, AND PHASE FUNCTIONS
Jewitt, David C.
TIME-RESOLVED PHOTOMETRY OF KUIPER BELT OBJECTS: ROTATIONS, SHAPES, AND PHASE FUNCTIONS Scott S are less spherical than their main-belt asteroid counterparts, indicating a higher specific angular measured phase darkening for seven Kuiper belt objects in the 0 to 2 phase-angle range. Unlike Pluto
On-demand generation of aqueous two-phase microdroplets with reversible phase transitions
Boreyko, Jonathan B [ORNL; Mruetusatorn, Prachya [ORNL; Retterer, Scott T [ORNL; Collier, Pat [ORNL
2013-01-01T23:59:59.000Z
Aqueous two-phase systems contained entirely within microdroplets enable a bottom-up approach to mimicking the dynamic microcompartmentation of biomaterial that naturally occurs within the cytoplasm of cells. Here, we demonstrate the on-demand generation of femtolitre aqueous two-phase droplets within a microfluidic oil channel. Gated pressure pulses were used to generate individual, stationary two-phase microdroplets with a well-defined time zero for carrying out controlled and sequential phase transformations over time. Reversible phase transitions between single-phase, two-phase, and core-shell microgel states were obtained via evaporation-induced dehydration and on-demand water rehydration. In contrast to other microfluidic aqueous two-phase droplets, which require continuous flows and high-frequency droplet formation, our system enables the controlled isolation and reversible transformation of a single microdroplet and is expected to be useful for future studies in dynamic microcompartmentation and affinity partitioning.
Rueda, D.R.; Garcia-Gutierrez, M.C.; Nogales, A.; Capitan, M.J.; Ezquerra, T.A.; Labrador, A.; Fraga, E.; Beltran, D.; Juanhuix, J.; Herranz, J.F.; Bordas, J. [Instituto de Estructura de la Materia, CSIC, Serrano 119, 28006 Madrid (Spain); LLS, BM16-ESRF, 6 rue Jules Horowitz, BP220, 38043 Grenoble (France)
2006-03-15T23:59:59.000Z
Here we present a novel, simple, and versatile experimental setup aimed to perform wide angle x-ray scattering (WAXS) measurements alone or in simultaneous combination with small angle x-ray scattering measurements. The design of the WAXS goniometer allows one to obtain high resolution diffraction patterns in a broad angular range. The setup can incorporate a hot stage in order to evaluate temperature resolved experiments. The performance of the equipment has been verified in the BM16 beam line of the European Synchrotron Radiation Facility with different well known samples such as alumina, isotropic film of high density polyethylene (HDPE), and oriented HPDE fiber.
SANS -Small Angle Neutron Scattering Tcnica de difrao
Loh, Watson
SANS - Small Angle Neutron Scattering Técnica de difração informações sobre tamanho e forma de- Neutrons are created in the centre of the target station when the beam of high energy protons collides by evaporating nuclear particles, mainly neutrons, in all directions. Each proton produces approximately 15
Wind Turbine Pitch Angle Controllers for Grid Frequency Stabilisation
Wind Turbine Pitch Angle Controllers for Grid Frequency Stabilisation Clemens Jauch Risø National Laboratory Wind Energy Department P.O. Box 49 DK-4000 Roskilde, Denmark clemens.jauch@risoe.dk Abstract: In this paper it is investigated how active-stall wind turbines can contribute to the stabilisation of the power
Neutrino Mass Models: Impact of non-zero reactor angle
Stephen F. King
2011-06-25T23:59:59.000Z
In this talk neutrino mass models are reviewed and the impact of a non-zero reactor angle and other deviations from tri-bimaximal mixing are discussed. We propose some benchmark models, where the only way to discriminate between them is by high precision neutrino oscillation experiments.
PRTAD: A DATABASE FOR PROTEIN RESIDUE TORSION ANGLE DISTRIBUTIONS
PRTAD: A DATABASE FOR PROTEIN RESIDUE TORSION ANGLE DISTRIBUTIONS By Xiaoyong Sun Di Wu RobertÂ0436 Phone: 612-624-6066 Fax: 612-626-7370 URL: http://www.ima.umn.edu #12;PRTAD: A Database for Protein@iastate.edu Abstract PRTAD is a dedicated database and structural bioinformatics system for protein analysis
Overview of Neutrino Mixing Models and Their Mixing Angle Predictions
Albright, Carl H.
2009-11-01T23:59:59.000Z
An overview of neutrino-mixing models is presented with emphasis on the types of horizontal flavor and vertical family symmetries that have been invoked. Distributions for the mixing angles of many models are displayed. Ways to differentiate among the models and to narrow the list of viable models are discussed.
Experimental Evaluation of an Angle Based Indoor Localization System
Nasipuri, Asis
Experimental Evaluation of an Angle Based Indoor Localization System Asis Nasipuri and Ribal El available off-the-shelf components. Wireless sensor nodes equipped with photo sensors determine is required at the sensor nodes. The system also does not involve any centralized server or off
The dynamics of two-phase (gas
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (MillionStructural Basis of WntSupportB 18B() |Portal Biomass and Biofuels Biomass CASLU.S.
Guinski, Rodrigo 1980-
2012-11-30T23:59:59.000Z
.................................................................................................. 40 Max/MSP/Jitter ............................................................................................. 41 Processing ..................................................................................................... 42 Interactivity... different technologies (LCD, CRT) and which textures could be obtained. This increased the repertoire of subjects that I would explore in the phasing loops. I compared Adobe Flash, Max/MSP Jitter and Processing in order to identify the best option...
Asymmetric-cut variable-incident-angle monochromator
Smither, R. K.; Fernandez, P. B.; Mills, D. M. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Graber, T. J. [Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637 (United States)
2012-03-15T23:59:59.000Z
A novel asymmetric-cut variable-incident-angle monochromator was constructed and tested in 1997 at the Advanced Photon Source of Argonne National Laboratory. The monochromator was originally designed as a high heat load monochromator capable of handling 5-10 kW beams from a wiggler source. This was accomplished by spreading the x-ray beam out on the surface an asymmetric-cut crystal and by using liquid metal cooling of the first crystal. The monochromator turned out to be a highly versatile monochromator that could perform many different types of experiments. The monochromator consisted of two 18 deg. asymmetrically cut Si crystals that could be rotated about 3 independent axes. The first stage ({Phi}) rotates the crystal around an axis perpendicular to the diffraction plane. This rotation changes the angle of the incident beam with the surface of the crystal without changing the Bragg angle. The second rotation ({Psi}) is perpendicular to the first and is used to control the shape of the beam footprint on the crystal. The third rotation ({Theta}) controls the Bragg angle. Besides the high heat load application, the use of asymmetrically cut crystals allows one to increase or decrease the acceptance angle for crystal diffraction of a monochromatic x-ray beam and allows one to increase or decrease the wavelength bandwidth of the diffraction of a continuum source like a bending-magnet beam or a normal x-ray-tube source. When the monochromator is used in the doubly expanding mode, it is possible to expand the vertical size of the double-diffracted beam by a factor of 10-15. When this was combined with a bending magnet source, it was possible to generate an 8 keV area beam, 16 mm wide by 26 mm high with a uniform intensity and parallel to 1.2 arc sec that could be applied in imaging experiments.
Small-Angle Neutron Scattering Studies of Charged Carboxyl-Terminated Dendrimers in Solutions
Dubin, Paul D.
Small-Angle Neutron Scattering Studies of Charged Carboxyl-Terminated Dendrimers in Solutions Q. R-angle neutron scattering was used to characterize the solution behavior of charged carboxylic acid terminated- copy,16 small-angle X-ray scattering,17 and small-angle neutron scattering (SANS),18-25 have been used
Lichtenegger, Helga C.
Variation of Cellulose Microfibril Angles in Softwoods and Hardwoods-- A Possible Strategy beech). The tilt angle of the cellulose fibrils in the wood cell wall versus the longitudinal cell axis Words: cellulose; hardwood; microfibril angle; small-angle scattering; softwood; wood; X
Pumice-pumice collisions and the effect of the impact angle B. Cagnoli and M. Manga
Manga, Michael
results show that the rebound angle, the ratios of the components of velocities and the energy loss vary observed relatively larger rebound angles at small and large impact angles and smaller values in between the impact angle increases. Furthermore, the ratio of the kinetic energy after to that before collisions
Dynamical friction in modified Newtonian dynamics
C. Nipoti; L. Ciotti; J. Binney; P. Londrillo
2008-03-31T23:59:59.000Z
We have tested a previous analytical estimate of the dynamical friction timescale in Modified Newtonian Dynamics (MOND) with fully non-linear N-body simulations. The simulations confirm that the dynamical friction timescale is significantly shorter in MOND than in equivalent Newtonian systems, i.e. systems with the same phase-space distribution of baryons and additional dark matter. An apparent conflict between this result and the long timescales determined for bars to slow and mergers to be completed in previous N-body simulations of MOND systems is explained. The confirmation of the short dynamical-friction timescale in MOND underlines the challenge that the Fornax dwarf spheroidal poses to the viability of MOND.
A technique for estimating 4D-CBCT using prior knowledge and limited-angle projections
Zhang, You [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 (United States)] [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 (United States); Yin, Fang-Fang; Ren, Lei [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 and Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)] [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 and Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Segars, W. Paul [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 and Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States)] [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 and Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States)
2013-12-15T23:59:59.000Z
Purpose: To develop a technique to estimate onboard 4D-CBCT using prior information and limited-angle projections for potential 4D target verification of lung radiotherapy.Methods: Each phase of onboard 4D-CBCT is considered as a deformation from one selected phase (prior volume) of the planning 4D-CT. The deformation field maps (DFMs) are solved using a motion modeling and free-form deformation (MM-FD) technique. In the MM-FD technique, the DFMs are estimated using a motion model which is extracted from planning 4D-CT based on principal component analysis (PCA). The motion model parameters are optimized by matching the digitally reconstructed radiographs of the deformed volumes to the limited-angle onboard projections (data fidelity constraint). Afterward, the estimated DFMs are fine-tuned using a FD model based on data fidelity constraint and deformation energy minimization. The 4D digital extended-cardiac-torso phantom was used to evaluate the MM-FD technique. A lung patient with a 30 mm diameter lesion was simulated with various anatomical and respirational changes from planning 4D-CT to onboard volume, including changes of respiration amplitude, lesion size and lesion average-position, and phase shift between lesion and body respiratory cycle. The lesions were contoured in both the estimated and “ground-truth” onboard 4D-CBCT for comparison. 3D volume percentage-difference (VPD) and center-of-mass shift (COMS) were calculated to evaluate the estimation accuracy of three techniques: MM-FD, MM-only, and FD-only. Different onboard projection acquisition scenarios and projection noise levels were simulated to investigate their effects on the estimation accuracy.Results: For all simulated patient and projection acquisition scenarios, the mean VPD (±S.D.)/COMS (±S.D.) between lesions in prior images and “ground-truth” onboard images were 136.11% (±42.76%)/15.5 mm (±3.9 mm). Using orthogonal-view 15°-each scan angle, the mean VPD/COMS between the lesion in estimated and “ground-truth” onboard images for MM-only, FD-only, and MM-FD techniques were 60.10% (±27.17%)/4.9 mm (±3.0 mm), 96.07% (±31.48%)/12.1 mm (±3.9 mm) and 11.45% (±9.37%)/1.3 mm (±1.3 mm), respectively. For orthogonal-view 30°-each scan angle, the corresponding results were 59.16% (±26.66%)/4.9 mm (±3.0 mm), 75.98% (±27.21%)/9.9 mm (±4.0 mm), and 5.22% (±2.12%)/0.5 mm (±0.4 mm). For single-view scan angles of 3°, 30°, and 60°, the results for MM-FD technique were 32.77% (±17.87%)/3.2 mm (±2.2 mm), 24.57% (±18.18%)/2.9 mm (±2.0 mm), and 10.48% (±9.50%)/1.1 mm (±1.3 mm), respectively. For projection angular-sampling-intervals of 0.6°, 1.2°, and 2.5° with the orthogonal-view 30°-each scan angle, the MM-FD technique generated similar VPD (maximum deviation 2.91%) and COMS (maximum deviation 0.6 mm), while sparser sampling yielded larger VPD/COMS. With equal number of projections, the estimation results using scattered 360° scan angle were slightly better than those using orthogonal-view 30°-each scan angle. The estimation accuracy of MM-FD technique declined as noise level increased.Conclusions: The MM-FD technique substantially improves the estimation accuracy for onboard 4D-CBCT using prior planning 4D-CT and limited-angle projections, compared to the MM-only and FD-only techniques. It can potentially be used for the inter/intrafractional 4D-localization verification.
Advanced slow-magic angle spinning probe for magnetic resonance imaging and spectroscopy
Wind, Robert A.; Hu, Jian Zhi; Minard, Kevin R.; Rommereim, Donald N.
2006-01-24T23:59:59.000Z
The present invention relates to a probe and processes useful for magnetic resonance imaging and spectroscopy instruments. More particularly, the invention relates to a MR probe and processes for obtaining resolution enhancements of fluid objects, including live specimens, using an ultra-slow (magic angle) spinning (MAS) of the specimen combined with a modified phase-corrected magic angle turning (PHORMAT) pulse sequence. Proton NMR spectra were measured of the torso and the top part of the belly of a female BALBc mouse in a 2T field, while spinning the animal at a speed of 1.5 Hz. Results show that even in this relatively low field with PHORMAT, an isotropic spectrum is obtained with line widths that are a factor 4.6 smaller than those obtained in a stationary mouse. Resolution of ^{1}H NMR metabolite spectra are thus significantly enhanced. Results indicate that PHORMAT has the potential to significantly increase the utility of ^{1}H NMR spectroscopy for in vivo biochemical, biomedical and/or medical applications involving large-sized biological objects such as mice, rats and even humans within a hospital setting. For small-sized objects, including biological objects, such as excised tissues, organs, live bacterial cells, and biofilms, use of PASS at a spinning rate of 30 Hz and above is preferred.
A high-order harmonic generation apparatus for time- and angle-resolved photoelectron spectroscopy
Frietsch, B.; Gahl, C.; Teichmann, M.; Weinelt, M. [Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany)] [Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany); Carley, R. [Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany) [Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany); Max-Born-Institut, Max-Born-Str. 2a, 12489 Berlin (Germany); Döbrich, K. [Max-Born-Institut, Max-Born-Str. 2a, 12489 Berlin (Germany)] [Max-Born-Institut, Max-Born-Str. 2a, 12489 Berlin (Germany); Schwarzkopf, O.; Wernet, Ph. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin (Germany)] [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin (Germany)
2013-07-15T23:59:59.000Z
We present a table top setup for time- and angle-resolved photoelectron spectroscopy to investigate band structure dynamics of correlated materials driven far from equilibrium by femtosecond laser pulse excitation. With the electron-phonon equilibration time being in the order of 1–2 ps it is necessary to achieve sub-picosecond time resolution. Few techniques provide both the necessary time and energy resolution to map non-equilibrium states of the band structure. Laser-driven high-order harmonic generation is such a technique. In our experiment, a grating monochromator delivers tunable photon energies up to 40 eV. A photon energy bandwidth of 150 meV and a pulse duration of 100 fs FWHM allow us to cover the k-space necessary to map valence bands at different k{sub z} and detect outer core states.
Chen, Wei-Ren [ORNL; Do, Changwoo [ORNL; Hong, Kunlun [ORNL; Liu, Emily [Rensselaer Polytechnic Institute (RPI); Liu, Yun [National Institute of Standards and Technology (NIST); Porcar, L. [National Institute of Standards and Technology (NIST); Smith, Gregory Scott [ORNL; Wu, Bin [ORNL; Egami, T [University of Tennessee, Knoxville (UTK); Smith, Sean C [ORNL
2012-01-01T23:59:59.000Z
Based on atomistic molecular dynamics (MD) simulations, the small angle neutron scattering (SANS) intensity behavior of a single generation-4 (G4) polyelectrolyte polyamidoamine (PAMAM) starburst dendrimer is investigated at different levels of molecular protonation. The SANS form factor, P(Q), and Debye autocorrelation function, (r), are calculated from the equilibrium MD trajectory based on a mathematical approach proposed in this work which provides a link between the neutron scattering experiment and MD computation. The simulations enable scattering calculations of not only the hydrocarbons, but also the contribution to the scattering length density fluctuations caused by structured, confined water within the dendrimer. Based on our computational results, we question the validity of using radius of gyration RG for microstructure characterization of a polyelectrolyte dendrimer from the scattering perspective.
Hanold, R.J.
1983-12-01T23:59:59.000Z
The two-phase flow program is directed at understanding the hydrodynamics of two-phase flows. The two-phase flow regime is characterized by a series of flow patterns that are designated as bubble, slug, churn, and annular flow. Churn flow has received very little scientific attention. This lack of attention cannot be justified because calculations predict that the churn flow pattern will exist over a substantial portion of the two-phase flow zone in producing geothermal wells. The University of Houston is experimentally investigating the dynamics of churn flow and is measuring the holdup over the full range of flow space for which churn flow exists. These experiments are being conducted in an air/water vertical two-phase flow loop. Brown University has constructed and is operating a unique two-phase flow research facility specifically designed to address flow problems of relevance to the geothermal industry. An important feature of the facility is that it is dedicated to two-phase flow of a single substance (including evaporation and condensation) as opposed to the case of a two-component two-phase flow. This facility can be operated with horizontal or vertical test sections of constant diameter or with step changes in diameter to simulate a geothermal well profile.
Geometric phases for generalized squeezed coherent states
S. Seshadri; S. Lakshmibala; V. Balakrishnan
1999-05-31T23:59:59.000Z
A simple technique is used to obtain a general formula for the Berry phase (and the corresponding Hannay angle) for an arbitrary Hamiltonian with an equally-spaced spectrum and appropriate ladder operators connecting the eigenstates. The formalism is first applied to a general deformation of the oscillator involving both squeezing and displacement. Earlier results are shown to emerge as special cases. The analysis is then extended to multiphoton squeezed coherent states and the corresponding anholonomies deduced.
Running of Low-Energy Neutrino Masses, Mixing Angles and CP Violation
John Ellis; Andi Hektor; Mario Kadastik; Kristjan Kannike; Martti Raidal
2005-06-13T23:59:59.000Z
We calculate the running of low-energy neutrino parameters from the bottom up, parameterizing the unknown seesaw parameters in terms of the dominance matrix $R$. We find significant running only if the $R$ matrix is non-trivial and the light-neutrino masses are moderately degenerate. If the light-neutrino masses are very hierarchical, the quark-lepton complementarity relation $\\theta_c + \\theta_{12} = \\pi/4$ is quite stable, but $\\theta_{13,23}$ may run beyond their likely future experimental errors. The running of the oscillation phase $\\delta$ is enhanced by the smallness of $\\theta_{13}$, and jumps in the mixing angles occur in cases where the light-neutrino mass eigenstates cross.
Patchy worm-like micelles: solution structure studied by small-angle neutron scattering
S. Rosenfeldt; F. Luedel; C. Schulreich; T. Hellweg; A. Radulescu; J. Schmelz; H. Schmalz; L. Harnau
2012-09-20T23:59:59.000Z
Triblock terpolymers exhibit a rich self-organization behavior including the formation of fascinating cylindrical core-shell structures with a phase separated corona. After crystallization-induced self-assembly of polystryrene-(block)-polyethylene-(block)-poly(methyl methacrylate) triblock terpolymers (abbreviated as SEMs = Styrene-Ethylene-Methacrylates) from solution, worm-like core-shell micelles with a patchy corona of polystryrene and poly(methyl methacrylate) were observed by transmission electron microscopy. However, the solution structure is still a matter of debate. Here, we present a method to distinguish in-situ between a Janus-type (two faced) and a patchy (multiple compartments) configuration of the corona. To discriminate between both models the scattering intensity must be determined mainly by one corona compartment. Contrast variation in small-angle neutron scattering enables us to focus on one compartment of the SEMs. The results validate the existence of the patchy structure also in solution.
Guidance system for low angle silicon ribbon growth
Jewett, David N. (Harvard, MA); Bates, Herbert E. (Ashby, MA); Milstein, Joseph B. (Denver, CO)
1986-07-08T23:59:59.000Z
In a low angle silicon sheet growth process, a puller mechanism advances a seed crystal and solidified ribbon from a cooled growth zone in a melt at a low angle with respect to the horizontal. The ribbon is supported on a ramp adjacent the puller mechanism. Variations in the vertical position of the ribbon with respect to the ramp are isolated from the growth end of the ribbon by (1) growing the ribbon so that it is extremely thin, preferably less than 0.7 mm, (2) maintaining a large growth zone, preferably one whose length is at least 5.0 cm, and (3) spacing the ramp from the growth zone by at least 15 cm.
Metal oxide morphology in argon-assisted glancing angle deposition
Sorge, J. B.; Taschuk, M. T.; Wakefield, N. G.; Sit, J. C.; Brett, M. J. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 2V4 (Canada); Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 2V4 (Canada) and NRC National Institute for Nanotechnology, Edmonton, AB T6G 2M9 (Canada)
2012-03-15T23:59:59.000Z
Glancing angle deposition (GLAD) is a thin film deposition technique capable of fabricating columnar architectures such as posts, helices, and chevrons with control over nanoscale film features. Argon bombardment during deposition modifies the GLAD process, producing films with new morphologies which have shown promise for sensing and photonic devices. The authors report modification of column tilt angle, film density, and specific surface area for 12 different metal oxide and fluoride film materials deposited using Ar-assisted GLAD. For the vapor flux/ion beam geometry and materials studied here, with increasing argon flux, the column tilt increases, film density increases, and specific surface area decreases. With a better understanding of the nature of property modification and the mechanisms responsible, the Ar-assisted deposition process can be more effectively targeted towards specific applications, including birefringent thin films or photonic crystal square spirals.
Pitch-angle scattering of energetic particles with adiabatic focusing
Tautz, R. C. [Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Hardenbergstraße 36, D-10623 Berlin (Germany); Shalchi, A. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Dosch, A., E-mail: robert.c.tautz@gmail.com, E-mail: andreasm4@yahoo.com, E-mail: alexanderm.dosch@gmail.com [Center for Space Plasmas and Aeronomic Research, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35805 (United States)
2014-10-20T23:59:59.000Z
Understanding turbulent transport of charged particles in magnetized plasmas often requires a model for the description of random variations in the particle's pitch angle. The Fokker-Planck coefficient of pitch-angle scattering, which is used to describe scattering parallel to the mean magnetic field, is therefore of central importance. Whereas quasi-linear theory assumes a homogeneous mean magnetic field, such a condition is often not fulfilled, especially for high-energy particles. Here, a new derivation of the quasi-linear approach is given that is based on the unperturbed orbit found for an adiabatically focused mean magnetic field. The results show that, depending on the ratio of the focusing length and the particle's Larmor radius, the Fokker-Planck coefficient is significantly modified but agrees with the classical expression in the limit of a homogeneous mean magnetic field.
Small angle neutron scattering in materials science: Recent practical applications
Melnichenko, Yuri B [ORNL; Wignall, George D [ORNL
2007-01-01T23:59:59.000Z
Modern materials science and engineering relies increasingly on detailed knowledge of the structure and interactions in 'soft' and 'hard' materials, but there have been surprisingly few microscopic techniques for probing the structures of bulk samples of these substances. Small-angle neutron scattering (SANS) was first recognized in Europe as a major technique for this purpose and, over the past several decades, has been a growth area in both academic and industrial materials research to provide structural information on length scales {approx}10-1000 Angstroms (or 1-100 nm). The technique of ultrahigh resolution small-angle neutron scattering (USANS) raises the upper resolution limit for structural studies by more than two orders of magnitude and (up to {approx}30 {micro}m) and hence overlaps with light scattering and microscopy. This review illustrates the ongoing vitality of SANS and USANS in materials research via a range of current practical applications from both soft and hard matter nanostructured systems.
Pitch Perfect: How Fruit Flies Control their Body Pitch Angle
Whitehead, Samuel C; Canale, Luca; Cohen, Itai
2015-01-01T23:59:59.000Z
Flapping insect flight is a complex and beautiful phenomenon that relies on fast, active control mechanisms to counter aerodynamic instability. To directly investigate how freely-flying D. melanogaster control their body pitch angle against such instability, we perturb them using impulsive mechanical torques and film their corrective maneuvers with high-speed video. Combining experimental observations and numerical simulation, we find that flies correct for pitch deflections of up to 40 degrees in 29 +/- 8 ms by bilaterally modulating their wings' front-most stroke angle in a manner well-described by a linear proportional-integral (PI) controller. Flies initiate this corrective process after only 10 +/- 2 ms, indicating that pitch stabilization involves a fast reflex response. Remarkably, flies can also correct for very large-amplitude pitch perturbations--greater than 150 degrees--providing a regime in which to probe the limits of the linear-response framework. Together with previous studies regarding yaw an...
Electron energy spectrum and maximum disruption angle under multi...
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ACCELERATORS; RADIATIONS; RESOLUTION; SPECTRA 430200* -- Particle Accelerators-- Beam Dynamics, Field Calculations, & Ion Optics Word Cloud More Like This Full Text preview image...
Impact Angle Control of Interplanetary Shock Geoeffectiveness: A Statistical Study
Oliveira, D M
2015-01-01T23:59:59.000Z
We present a survey of interplanetary (IP) shocks using WIND and ACE satellite data from January 1995 to December 2013 to study how IP shock geoeffectiveness is controlled by IP shock impact angles. A shock list covering one and a half solar cycle is compiled. The yearly number of IP shocks is found to correlate well with the monthly sunspot number. We use data from SuperMAG, a large chain with more than 300 geomagnetic stations, to study geoeffectiveness triggered by IP shocks. The SuperMAG SML index, an enhanced version of the familiar AL index, is used in our statistical analysis. The jumps of the SML index triggered by IP shock impacts on the Earth's magnetosphere is investigated in terms of IP shock orientation and speed. We find that, in general, strong (high speed) and almost frontal (small impact angle) shocks are more geoeffective than inclined shocks with low speed. The strongest correlation (correlation coefficient R = 0.70) occurs for fixed IP shock speed and varying the IP shock impact angle. We ...
THE DYNAMICS OF THREE-PLANET SYSTEMS: AN APPROACH FROM A DYNAMICAL SYSTEM
Shikita, Bungo; Yamada, Shoichi [Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Koyama, Hiroko, E-mail: shikita@heap.phys.waseda.ac.j [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)
2010-04-01T23:59:59.000Z
We study in detail the motions of three planets interacting with each other under the influence of a central star. It is known that the system with more than two planets becomes unstable after remaining quasi-stable for long times, leading to highly eccentric orbital motions or ejections of some of the planets. In this paper, we are concerned with the underlying physics for this quasi-stability as well as the subsequent instability and advocate the so-called stagnant motion in the phase space, which has been explored in the field of a dynamical system. We employ the Lyapunov exponent, the power spectra of orbital elements, and the distribution of the durations of quasi-stable motions to analyze the phase-space structure of the three-planet system, the simplest and hopefully representative one that shows the instability. We find from the Lyapunov exponent that the system is almost non-chaotic in the initial quasi-stable state whereas it becomes intermittently chaotic thereafter. The non-chaotic motions produce the horizontal dense band in the action-angle plot whereas the voids correspond to the chaotic motions. We obtain power laws for the power spectra of orbital eccentricities. Power-law distributions are also found for the durations of quasi-stable states. With all these results combined together, we may reach the following picture: the phase space consists of the so-called KAM tori surrounded by satellite tori and imbedded in the chaotic sea. The satellite tori have a self-similar distribution and are responsible for the scale-free power-law distributions of the duration times. The system is trapped around one of the KAM torus and the satellites for a long time (the stagnant motion) and moves to another KAM torus with its own satellites from time to time, corresponding to the intermittent chaotic behaviors.
ALIGNMENT OF PROTOSTARS AND CIRCUMSTELLAR DISKS DURING THE EMBEDDED PHASE
Spalding, Christopher; Batygin, Konstantin [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Adams, Fred C., E-mail: cspaldin@caltech.edu, E-mail: kbatygin@gps.caltech.edu, E-mail: fca@umich.edu [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States)
2014-12-20T23:59:59.000Z
Star formation proceeds via the collapse of a molecular cloud core over multiple dynamical timescales. Turbulence within cores results in a spatially non-uniform angular momentum of the cloud, causing a stochastic variation in the orientation of the disk forming from the collapsing material. In the absence of star-disk angular momentum coupling, such disk-tilting would provide a natural mechanism for the production of primordial spin-orbit misalignments in the resulting planetary systems. However, owing to high accretion rates in the embedded phase of star formation, the inner edge of the circumstellar disk extends down to the stellar surface, resulting in efficient gravitational and accretional angular momentum transfer between the star and the disk. Here, we demonstrate that the resulting gravitational coupling is sufficient to suppress any significant star-disk misalignment, with accretion playing a secondary role. The joint tilting of the star-disk system leads to a stochastic wandering of star-aligned bipolar outflows. Such wandering widens the effective opening angle of stellar outflows, allowing for more efficient clearing of the remainder of the protostar's gaseous envelope. Accordingly, the processes described in this work provide an additional mechanism responsible for sculpting the stellar initial mass function.
2002 AUGUST 24 LIMB FLARE LOOP: DYNAMICS OF MICROWAVE BRIGHTNESS DISTRIBUTION
Reznikova, V. E.; Ji, H. [Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008 (China); Melnikov, V. F.; Gorbikov, S. P.; Pyatakov, N. P. [Radiophysical Research Institute (NIRFI), Nizhny Novgorod 603950 (Russian Federation); Shibasaki, K. [Nobeyama Solar Radio Observatory/NAOJ, Nagano 384-1305 (Japan); Myagkova, I. N. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation)], E-mail: vreznikova@nirfi.sci-nnov.ru
2009-05-20T23:59:59.000Z
High-resolution radio observation of Nobeyama Radioheliograph at 17 and 34 GHz allowed studying the dynamics of microwave brightness distribution along the giant limb flaring loop in the event of 2002 August 24. It is found that on the rising phase of the radio burst the brightness distribution was highly asymmetric, with a strong maximum near the southern footpoint (SFP) and much weaker brightness enhancements near the loop top (LT) and northern footpoint. On the decay phase, the LT gradually became most bright. The similar dynamics of brightness distribution are shown to happen for all major temporal subpeaks of the burst. Results of our diagnostics show two important properties: (1) the number density of mildly relativistic electrons in the LT is much higher than near the footpoints (FPs) during rise, maximum and decay of each major peak; and (2) the ratio of the electron number densities in the LT and an FP increases from the maximum to decay phase. Model simulations with making use of the nonstationary Fokker-Planck equation have allowed us to find the model explaining the major properties of the microwave brightness distribution and dynamics. The model is characterized by a compact source of electrons located near the center of an asymmetric magnetic loop; the source is nonstationary, long lasting, and injecting high-energy electrons with the pitch-angle distribution mostly directed toward the SFP but also having a very weak isotropic component. This easily explains the observed brightness asymmetry. The observed dynamics comes due to two reasons: faster precipitation of electrons having their mirror points near the ends of the magnetic trap, and relatively faster decay of the lower energy electrons responsible for the gyrosynchrotron emission near the FPs with higher magnetic field.
Dynamical analysis of highly excited molecular spectra
Kellman, M.E. [Univ. of Oregon, Eugene (United States)
1993-12-01T23:59:59.000Z
The goal of this program is new methods for analysis of spectra and dynamics of highly excited vibrational states of molecules. In these systems, strong mode coupling and anharmonicity give rise to complicated classical dynamics, and make the simple normal modes analysis unsatisfactory. New methods of spectral analysis, pattern recognition, and assignment are sought using techniques of nonlinear dynamics including bifurcation theory, phase space classification, and quantization of phase space structures. The emphasis is chaotic systems and systems with many degrees of freedom.
Natural Dynamics for Combinatorial Optimization
Ovchinnikov, Igor V
2015-01-01T23:59:59.000Z
Stochastic and or natural dynamical systems (DSs) are dominated by sudden nonlinear processes such as neuroavalanches, gamma-ray bursts, solar flares, earthquakes etc. that exhibit scale-free statistics. These behaviors also occur in many nanosystems. On phase diagrams, these DSs belong to a finite-width phase that separates the phases of thermodynamic equilibrium and ordinary chaotic dynamics, and that is known under such names as intermittency, noise-induced chaos, and self-organized criticality. Within the recently formulated approximation-free cohomological theory of stochastic differential equations, the noise-induced chaos can be roughly interpreted as a noise-induced overlap between regular (integrable) and chaotic (non-integrable) deterministic dynamics so that DSs in this phase inherit the properties of the both. Here, we analyze this unique set of properties and conclude that such DSs must be the most efficient natural optimizers. Based on this understanding, we propose the method of the natural dyn...
Inspection of Historic Steel Bridges Using Ultrasonic Phased Array
Roldan Arcos, Alejandra L
2014-01-16T23:59:59.000Z
the sleeves. . . . . . . . . . . . . . . . . . . . . . . . . 27 4.1 Conventional ultrasonic usage of longitudinal and shear waves. . . . . . . 28 4.2 A linear wavefront resulting from a simultaneous timing of the 16 elements in a phased array. Recreated from... back in the system. Phased arrays can use multiple elements, following a user-specified focus law, to detect imperfections. This allows for a sweep scan through different angles with a single probe, covering more area than a conventional ul- trasonic...
Substructure in clusters containing wide-angle tailed radio galaxies. I. New redshifts
Jason Pinkney; Jack O. Burns; Michael J. Ledlow; Percy L. Gomez; John M. Hill
2000-11-08T23:59:59.000Z
We present new redshifts and positions for 635 galaxies in nine rich clusters containing Wide-Angle Tailed (WAT) radio galaxies. Combined with existing data, we now have a sample of 18 WAT-containing clusters with more than 10 redshifts. This sample contains a substantial portion of the WAT clusters in the VLA 20 cm survey of Abell clusters, including 75% of WAT clusters in the complete survey (z0.09. It is a representative sample which should not contain biases other than selection by radio morphology. We graphically present the new data using histograms and sky maps. A semi-automated procedure is used to search for emission lines in the spectra in order to add and verify galaxy redshifts. We find that the average apparent fraction of emission line galaxies is about 9% in both the clusters and the field. We investigate the magnitude completeness of our redshift surveys with CCD data for a test case, Abell 690. This case indicates that our galaxy target lists are deeper than the detection limit of a typical MX exposure, and they are 82% complete down to R=19.0. The importance of the uniformity of the placement of fibers on targets is posited, and we evaluate this in our datasets. We find some cases of non-uniformities which may influence dynamical analyses. A second paper will use this database to look for correlations between the WAT radio morphology and the cluster's dynamical state.
Mohaghegh, Shahab
-oil ratios in two phase systems, water flow in three phase systems, and inclination angles of the pipe information such as oil, gas and water flow rates, temperature, oil and gas gravity, pipe length, surface three-phase (oil, water, and gas) flow in wellbores. This tool applies to a variety of wells, including
Phase-space localization: Topological aspects of quantum chaos
Leboeuf, P. (Division de Physique Theorique, Institut de Physique Nucleire, 91406 Orsay CEDEX (France)); Kurchan, J. (Nuclear Physics Department, Weizmann Institute of Science, Rehovot 76100 (Israel)); Feingold, M. (Lawrence Berkeley Laboratory, University of California, Berkeley, CA (USA) Department of Physics, University of California, Berkeley, CA (USA)); Arovas, D.P. (Department of Physics, B-019, University of California at San Diego, La Jolla, CA (USA))
1990-12-17T23:59:59.000Z
We study quantized classically chaotic maps on a toroidal two-diensional phase space. A discrete, topological criterion for phase-space localization is presented. To each eigenfunction an integer is associated, analogous to a quantized Hall conductivity, which when nonzero reflects phase-space delocalization. A model system is studied, and a correspondence between delocalization and chaotic classical dynamics is discussed.
Small angle neutron scattering from high impact polystyrene
Pringle, O.A.
1981-01-01T23:59:59.000Z
High impact polystyrene (HIPS) is a toughened plastic composed of a polystyrene matrix containing a few percent rubber in the form of dispersed 0.1 to 10 micron diameter rubber particles. Some commercial formulations of HIPS include the addition of a few percent mineral oil, which improves the toughness of the plastic. Little is known about the mechanism by which the mineral oil helps toughen the plastic. It is hypothesized that the oil is distributed only in the rubber particles, but whether this hypothesis is correct was not known prior to this work. The size of the rubber particles in HIPS and their neutron scattering length density contrast with the polystyrene matrix cause HIPS samples to scatter neutrons at small angles. The variation of this small angle neutron scattering (SANS) signal with mineral oil content has been used to determine the location of the oil in HIPS. The SANS spectrometer at the University of Missouri Research Reactor Facility (MURR) was used to study plastic samples similar in composition to commercial HIPS. The MURR SANS spectrometer is used to study the small angle scattering of a vertical beam of 4.75 A neutrons from solid and liquid samples. The scattered neutrons are detected in a 54 x 60 cm/sup 2/ position sensitive detector designed and built at MURR. A series of plastic samples of varying rubber and oil content and different rubber domain sizes and shapes were examined on the MURR SANS spectrometer. Analysis of the scattering patterns showed that the mineral oil is about eight to ten times more likely to be found in the rubber particles than in the polystyrene matrix. This result confirmed the hypothesis that the mineral oil is distributed primarily in the rubber particles.
The reactor mixing angle and CP violation with two texture zeros in the light of T2K
P. O. Ludl; S. Morisi; E. Peinado
2012-01-24T23:59:59.000Z
We reconsider the phenomenological implications of two texture zeros in symmetric neutrino mass matrices in the light of the recent T2K result for the reactor angle and the new global analysis which gives also best fit values for the Dirac CP phase delta. The most important results of the analysis are: Among the viable cases classified by Frampton et al. only A1 and A2 predict the reactor mixing angle to be different from zero at 3 sigma. Furthermore these two cases are compatible only with a normal mass spectrum in the allowed region for the reactor angle. At the best fit value A1 and A2 predict 0.024 >= sin^2(theta13) >= 0.012 and 0.014 <= sin^2(theta13) <= 0.032, respectively, where the bounds on the right and the left correspond to cos(delta)=-1 and cos(delta)=1, respectively. The cases B1, B2, B3 and B4 predict nearly maximal CP violation, i.e. cos(delta) is approximately zero.
K. G. Arun; Hideyuki Tagoshi; Chandra Kant Mishra; Archana Pai
2014-12-15T23:59:59.000Z
Compact binary mergers are the strongest candidates for the progenitors of Short Gamma Ray Bursts (SGRBs). If a gravitational wave (GW) signal from the compact binary merger is observed in association with a SGRB, such a synergy can help us understand many interesting aspects of these bursts. We examine the accuracies with which a world wide network of gravitational wave interferometers would measure the inclination angle (the angle between the angular momentum axis of the binary and the observer's line of sight) of the binary. We compare the projected accuracies of GW detectors to measure the inclination angle of double neutron star (DNS) and neutron star-black hole (NS-BH) binaries for different astrophysical scenarios. We find that a 5 detector network can measure the inclination angle to an accuracy of $\\sim 5.1 (2.2)$ degrees for a DNS(NS-BH) system at 200 Mpc if the direction of the source as well as the redshift is known electromagnetically. We argue as to how an accurate estimation of the inclination angle of the binary can prove to be crucial in understanding off-axis GRBs, the dynamics and the energetics of their jets, and help the searches for (possible) orphan afterglows of the SGRBs.
Solid angle and surface density as criticality parameters
Thomas, J.T.
1980-10-01T23:59:59.000Z
Two methods often used to establish nuclear criticality safety limits for operations with fissile materials are the surface density and solid angle techniques. The two methods are used as parameters to express experimental and validated calculations of critical configurations. It is demonstrated that each method can represent critical arrangements of subcritical units and that there can be established a one-to-one correspondence between them. The analyses further show that the effect on an array neutron multiplication factor of perturbations to the array can be reliably estimated and that each form of fissile material and unit shape has a specific representation.
Pancharatnam Phase and Photon Polarization Optics
S. C. Tiwari
2006-02-04T23:59:59.000Z
Parallel transport of a vector around a closed curve on the surface of a sphere leads to a direction holonomy which can be related with a geometric phase that is equal to the solid angle subtended by the closed curve. Since Pancharatnam phase is half of the solid angle subtended by the polarization cycle on the Poincare sphere, quantum parallel transport law takes recourse o spin-half wave function to obtain this result. A critique is offered on this factor of half anomaly in the geometric phase, and a natural resolution using Riemann sphere polarization representation is suggested. It is argued that spin angular momentum of photon is fundamental in polarization optics, and new insights are gained based on the hypothesis that two helicity states correspond to two distinct species of photon. This approach leads to the concept of a physical Poincare sphere: nonlinearity and jumps in the Pancharatnam phase find a simple physical explanation while novel features pertaining to the discrete and pulsating sphere are predicted. Paired photon spin zero structure of unpolarized light is also discussed. An outline of possible experimental tests is presented.
Louis Reese; Anna Melbinger; Erwin Frey
2015-05-05T23:59:59.000Z
Here we study a driven lattice gas model for microtubule depolymerizing molecular motors, where traffic jams of motors induce stochastic switching between microtubule growth and shrinkage. We term this phenomenon \\enquote{traffic dynamic instability} because it is reminiscent of microtubule dynamic instability [T. Mitchison and M. Kirschner, Nature 312, 237 (1984)]. The intermittent dynamics of growth and shrinking emerges from the interplay between the arrival of motors at the microtubule tip, motor induced depolymerization, and motor detachment from the tip. The switching dynamics correlates with low and high motor density on the lattice. This leads to an effectively bistable particle density in the system. A refined domain wall theory predicts this transient appearance of different phases in the system. The theoretical results are supported by stochastic simulations.
Reese, Louis; Frey, Erwin
2015-01-01T23:59:59.000Z
Here we study a driven lattice gas model for microtubule depolymerizing molecular motors, where traffic jams of motors induce stochastic switching between microtubule growth and shrinkage. We term this phenomenon \\enquote{traffic dynamic instability} because it is reminiscent of microtubule dynamic instability [T. Mitchison and M. Kirschner, Nature 312, 237 (1984)]. The intermittent dynamics of growth and shrinking emerges from the interplay between the arrival of motors at the microtubule tip, motor induced depolymerization, and motor detachment from the tip. The switching dynamics correlates with low and high motor density on the lattice. This leads to an effectively bistable particle density in the system. A refined domain wall theory predicts this transient appearance of different phases in the system. The theoretical results are supported by stochastic simulations.
Correlation of Oil-Water and Air-Water Contact Angles of Diverse...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Oil-Water and Air-Water Contact Angles of Diverse Silanized Surfaces and Relationship to Fluid Interfacial Correlation of Oil-Water and Air-Water Contact Angles of Diverse...
Chen, Chung-De [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan (China); National Tsing Hua University, Hsinchu, Taiwan (China); Huang, Yen-Chieh [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan (China); Chiang, Hsin-Lin [National Tsing Hua University, Hsinchu, Taiwan (China); Hsieh, Yin-Cheng; Guan, Hong-Hsiang; Chuankhayan, Phimonphan [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan (China); Chen, Chun-Jung, E-mail: cjchen@nsrrc.org.tw [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan (China); National Tsing Hua University, Hsinchu, Taiwan (China); National Cheng Kung University, Tainan City 701, Taiwan (China); National Cheng Kung University, Tainan City 701, Taiwan (China)
2014-09-01T23:59:59.000Z
A novel direct phase-selection method to select optimized phases from the ambiguous phases of a subset of reflections to replace the corresponding initial SAD phases has been developed. With the improved phases, the completeness of built residues of protein molecules is enhanced for efficient structure determination. Optimization of the initial phasing has been a decisive factor in the success of the subsequent electron-density modification, model building and structure determination of biological macromolecules using the single-wavelength anomalous dispersion (SAD) method. Two possible phase solutions (?{sub 1} and ?{sub 2}) generated from two symmetric phase triangles in the Harker construction for the SAD method cause the well known phase ambiguity. A novel direct phase-selection method utilizing the ?{sub DS} list as a criterion to select optimized phases ?{sub am} from ?{sub 1} or ?{sub 2} of a subset of reflections with a high percentage of correct phases to replace the corresponding initial SAD phases ?{sub SAD} has been developed. Based on this work, reflections with an angle ?{sub DS} in the range 35–145° are selected for an optimized improvement, where ?{sub DS} is the angle between the initial phase ?{sub SAD} and a preliminary density-modification (DM) phase ?{sub DM}{sup NHL}. The results show that utilizing the additional direct phase-selection step prior to simple solvent flattening without phase combination using existing DM programs, such as RESOLVE or DM from CCP4, significantly improves the final phases in terms of increased correlation coefficients of electron-density maps and diminished mean phase errors. With the improved phases and density maps from the direct phase-selection method, the completeness of residues of protein molecules built with main chains and side chains is enhanced for efficient structure determination.
Stener, M., E-mail: stener@univ.trieste.it; Decleva, P. [Dipartimento di Scienze Chimiche e Farmaceutiche, Università di Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy) [Dipartimento di Scienze Chimiche e Farmaceutiche, Università di Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali Unita'di Trieste, 34127 Trieste (Italy); CNR-IOM DEMOCRITOS, 34149 Trieste (Italy)] [Italy; Mizuno, T.; Yagishita, A. [Photon Factory, Institute of Materials Structure Science, KEK, Oho 1-1, Tsukuba 305-0801 (Japan)] [Photon Factory, Institute of Materials Structure Science, KEK, Oho 1-1, Tsukuba 305-0801 (Japan); Yoshida, H. [Department of Chemistry, Hiroshima University, Higashi-Hiroshima, Hirosima 739-8526 (Japan)] [Department of Chemistry, Hiroshima University, Higashi-Hiroshima, Hirosima 739-8526 (Japan)
2014-01-28T23:59:59.000Z
F1s and C1s photoelectron angular distributions are considered for CH{sub 3}F, a molecule which does not support any shape resonance. In spite of the absence of features in the photoionization cross section profile, the recoil frame photoelectron angular distributions (RFPADs) exhibits dramatic changes depending on both the photoelectron energy and polarization geometry. Time-dependent density functional theory calculations are also given to rationalize the photoionization dynamics. The RFPADs have been compared with the theoretical calculations, in order to assess the accuracy of the theoretical method and rationalize the experimental findings. The effect of finite acceptance angles for both ionic fragments and photoelectrons has been included in the calculations, as well as the effect of rotational averaging around the fragmentation axis. Excellent agreement between theory and experiment is obtained, confirming the good quality of the calculated dynamical quantities (dipole moments and phase shifts)
A Large Sample Volume Magic Angle Spinning Nuclear Magnetic Resonance...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
the surface functional groups of HPAmeso-silicalite-1 under the condition of in-situ drying . We also show that the reaction dynamics of 2-butanol dehydration using HPA...
Lurio, L. B.; Mulders, N.; Paetkau, M.; Chan, M. H. W.; Mochrie, S. G. J. [Department of Physics, Northern Illinois University, DeKalb, Illinois 60115 (United States); Department of Physics, University of Delaware, Newark, Delaware 19716 (United States); Department of Physics and Astronomy, Okanagan College, British Columbia V1Y4X8 (Canada); Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Department of Physics, Yale University, New Haven, Connecticut 06511 (United States)
2007-07-15T23:59:59.000Z
Small-angle x-ray scattering (SAXS) was used to measure the microstructure of isotopic mixtures of {sup 3}He and {sup 4}He adsorbed into silica aerogels as a function of temperature and {sup 3}He concentration. The SAXS measurements could be well described by the formation of a nearly pure film of {sup 4}He which separates from the bulk mixture onto the aerogel strands and which thickens with decreasing temperature. Previous observations of a superfluid {sup 3}He-rich phase are consistent with superfluidity existing within this film phase. Observed differences between different density aerogels are explained in terms of the depletion of {sup 4}He from the bulk mixture due to film formation.
The Extended Q-Range Small Angle Neutron Scattering Diffractometer at the SNS
Zhao, Jinkui [ORNL; Gao, Carrie Y [ORNL; Liu, Dazhi [ORNL
2010-01-01T23:59:59.000Z
The Extended Q-Range Small Angle Neutron Scattering Diffractometer (EQ-SANS) at the Spallation Neutron Source is designed to have wide neutron momentum transfer (Q) coverage, high neutron beam intensity, and good wavelength resolution. In addition, the design and construction of the instrument aim at achieving maximum signal to noise ratio by minimizing the background. The instrument is located on the 60Hz SNS target. It has a primary flight path of 14m. Its secondary flight path varies from ~1m to 10m. One of the key components in the primary flight path is the neutron optics, consisting of a true-curved multi channel beam bender and sections of neutron guides. The optics is optimized to reduce the neutron transport loss to a minimum, thereby maximizing the available flux on sample. It also enables the avoidance of the direct line of sight of the neutron moderator at downstream locations. The instrument has three bandwidth-limiting choppers. These choppers effectively eliminate higher frame neutrons up to ~38 from the beam. A frame overlap mirror further cleans up the beam by reflecting out neutrons whose wavelengths are longer than ~33 . The bandwidth choppers also allow a frame-skipping mode of operation, which enables the EQ-SANS diffractometer to achieve a dynamic Q-range equivalent to that of a similar machine on a 20Hz source. The two-dimensional low-angle detector, based on 3He tube technologies, offers very high counting rates and counting efficiency. Initial operations have shown that the instrument has achieved its best-in-class design requirement.
Flavor instabilities in the multi-angle neutrino line model
Abbar, Sajad; Shalgar, Shashank
2015-01-01T23:59:59.000Z
Neutrino flavor oscillations in the presence of ambient neutrinos is nonlinear in nature which leads to interesting phenomenology that has not been well understood. It was recently shown that, in the two-dimensional, two-beam neutrino Line model, the inhomogeneous neutrino oscillation modes on small distance scales can become unstable at larger neutrino densities than the homogeneous mode does. We develop a numerical code to solve neutrino oscillations in the multi-angle/beam Line model with a continuous neutrino angular distribution. We show that the inhomogeneous oscillation modes can occur at even higher neutrino densities in the multi-angle model than in the two-beam model. We also find that the inhomogeneous modes on sufficiently small scales can be unstable at smaller neutrino densities with ambient matter than without, although a larger matter density does shift the instability region of the homogeneous mode to higher neutrino densities in the Line model as it does in the one-dimensional supernova Bulb...
Hydrophilic property by contact angle change of ion implanted polycarbonate
Lee, Chan Young; Kil, Jae Keun [Proton Engineering Frontier Project, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon, 305-600 (Korea, Republic of); R and D Team, Accel Korea, 146-1 Pyeongchon-dong Daeduck-gu Daejeon (Korea, Republic of)
2008-02-15T23:59:59.000Z
In this study, ion implantation was performed onto a polymer, polycarbonate (PC), in order to investigate surface hydrophilic property through contact angle measurement. PC was irradiated with N, Ar, and Xe ions at the irradiation energy of 20-50 keV and the dose range of 5x10{sup 15}, 1x10{sup 16}, 7x10{sup 16} ions/cm{sup 2}. The contact angle of water was estimated by means of the sessile drop method and was reduced with increasing fluence and ion mass but increased with increasing implanted energy. The changes of chemical and structural properties are discussed in view of Furier transform infrared and x-ray photoelectron spectroscopy, which shows increasing C-O bonding and C-C bonding. The surface roughness examined by atomic force microscopy measurement changed smoothly from 3.59 to 2.22 A as the fluence increased. It is concluded that the change in wettability may be caused by surface carbonization and oxidation as well as surface roughness.
G$^0$ Electronics and Data Acquisition (Forward-Angle Measurements)
D. Marchand; J. Arvieux; L. Bimbot; A. Biselli; J. Bouvier; H. Breuer; R. Clark; J. -C. Cuzon; M. Engrand; R. Foglio; C. Furget; X. Grave; B. Guillon; H. Guler; P. M. King; S. Kox; J. Kuhn; Y. Ky; J. Lachniet; J. Lenoble; E. Liatard; J. Liu; E. Munoz; J. Pouxe; G. Quéméner; B. Quinn; J. -S. Réal; O. Rossetto; R. Sellem
2007-03-15T23:59:59.000Z
The G$^0$ parity-violation experiment at Jefferson Lab (Newport News, VA) is designed to determine the contribution of strange/anti-strange quark pairs to the intrinsic properties of the proton. In the forward-angle part of the experiment, the asymmetry in the cross section was measured for $\\vec{e}p$ elastic scattering by counting the recoil protons corresponding to the two beam-helicity states. Due to the high accuracy required on the asymmetry, the G$^0$ experiment was based on a custom experimental setup with its own associated electronics and data acquisition (DAQ) system. Highly specialized time-encoding electronics provided time-of-flight spectra for each detector for each helicity state. More conventional electronics was used for monitoring (mainly FastBus). The time-encoding electronics and the DAQ system have been designed to handle events at a mean rate of 2 MHz per detector with low deadtime and to minimize helicity-correlated systematic errors. In this paper, we outline the general architecture and the main features of the electronics and the DAQ system dedicated to G$^0$ forward-angle measurements.
Incoherent photoproduction of pseudoscalar mesons off nuclei at forward angles
Gevorgyan, Sergey [JINR; Gasparian, Ashot H. [North Carolina Ag. and Tech. St. U; Gan, Liping [University of North Carolina at Wilmington; Larin, Ilya F. [ITEP, Moscow; Khandaker, Mahbubul A. [Idaho State U
2012-01-01T23:59:59.000Z
Recent advances in the photon tagging facilities together with the novel, high-resolution fast calorimetry make it possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths, needed for testing the symmetry breaking effects in QCD, from these measurements at small angles is done by the Primakoff method. This method requires theoretical treatment of all processes participating in these reactions at the same percent level. The most updated description of general processes, including the nuclear coherent amplitude, is done in our previous paper. In this work, in the framework of the Glauber multiple scattering theory, we obtain analytical expressions for the incoherent cross section of the photoproduction of pseudoscalar mesons off nuclei accounting for the mesons absorption in nuclei and the Pauli suppression at forward production angles. As illustrations of the obtained formulas, we calculate the incoherent cross section for photoproduction from a closed shell nucleus, {sup 16}O, and from an unclosed shell nucleus, {sup 12}C. These calculations allow one to compare different approaches and estimate their impact on the incoherent cross section of the processes under consideration.
Incoherent photoproduction of pseudoscalar mesons off nuclei at forward angles
S. Gevorkyan; A. Gasparian; L. Gan; I. Larin; M. Khandaker
2009-08-10T23:59:59.000Z
Recent advances in the photon tagging facilities together with the novel, high resolution fast calorimetry made possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths, needed for testing the symmetry breaking effects in QCD, from these measurements at small angles is done by the Primakoff method. This method requires theoretical treatment of all processes participating in these reactions at the same percent level. The most updated description of general processes, including the nuclear coherent amplitude, is done in our previous paper. In this work, based on the framework of Glauber multiple scattering theory, we obtain analytical expressions for the incoherent cross section of the photoproduction of pseudoscalar mesons off nuclei accounting for the mesons absorption in nuclei and Pauli suppression at forward production angles. As illustrations of the obtained formulas, we calculate the incoherent cross section for photoproduction from a closed shell nucleus, 16^O, and from an unclosed shell nucleus, 12^C. These calculations allow one to compare different approaches and estimate their impact on the incoherent cross section of the processes under consideration.
hal-00154048,version1-12Jun2007 The new very small angle neutron scattering
Boyer, Edmond
hal-00154048,version1-12Jun2007 The new very small angle neutron scattering spectrometer The design and characteristics of the new very small angle neutron scattering spectrometer under construction in order to fill the gap between light scattering and classical small angle neutron scattering (SANS
Rotation Angle for the Optimum Tracking of One-Axis Trackers
Marion, W. F.; Dobos, A. P.
2013-07-01T23:59:59.000Z
An equation for the rotation angle for optimum tracking of one-axis trackers is derived along with equations giving the relationships between the rotation angle and the surface tilt and azimuth angles. These equations are useful for improved modeling of the solar radiation available to a collector with tracking constraints and for determining the appropriate motor revolutions for optimum tracking.
Kumar, Pawan; Singh, Vishwesh; Tripathi, V. K. [Department of Physics, IIT Delhi, New Delhi-110016 (India)
2013-02-15T23:59:59.000Z
A kinetic formalism of lower hybrid wave instability, driven by mono-energy {alpha}-particles with finite pitch angle spread, is developed. The instability arises through cyclotron resonance interaction with high cyclotron harmonics of {alpha}-particles. The {alpha}-particles produced in D-T fusion reactions have huge Larmor radii ({approx}10 cm) as compared to the wavelength of the lower hybrid wave, whereas their speed is an order of magnitude smaller than the speed of light in vacuum. As a result, large parallel phase velocity lower hybrid waves, suitable for current drive in tokamak, are driven unstable via coupling to high cyclotron harmonics. The growth rate decreases with increase in pitch angle spread of the beam. At typical electron density of {approx}10{sup 19} m{sup -3}, magnetic field {approx}4 Tesla and {alpha}-particle concentration {approx}0.1%, the large parallel phase velocity lower hybrid wave grows on the time scale of 20 ion cyclotron periods. The growth rate decreases with plasma density.
Flexoelectric switching in cholesteric blue phases
A. Tiribocchi; M. E. Cates; G. Gonnella; D. Marenduzzo; E. Orlandini
2013-03-25T23:59:59.000Z
We present computer simulations of the response of a flexoelectric blue phase network, either in bulk or under confinement, to an applied field. We find a transition in the bulk between the blue phase I disclination network and a parallel array of disclinations along the direction of the applied field. Upon switching off the field, the system is unable to reconstruct the original blue phase but gets stuck in a metastable phase. Blue phase II is comparatively much less affected by the field. In confined samples, the anchoring at the walls and the geometry of the device lead to the stabilisation of further structures, including field-aligned disclination loops, splayed nematic patterns, and yet more metastable states. Our results are relevant to the understanding of the switching dynamics for a class of new, "superstable", blue phases which are composed of bimesogenic liquid crystals, as these materials combine anomalously large flexoelectric coefficients, and low or near-zero dielectric anisotropy.
New insight into the Berezinskii-Kosterlitz-Thouless phase transition
Urs Gerber; Wolfgang Bietenholz; Fernando G Rejón-Barrera
2014-02-11T23:59:59.000Z
We investigate the 2d XY model by using the constraint angle action, which belongs to the class of topological lattice actions. These actions violate important features usually demanded for a lattice action, such as the correct classical continuum limit and the applicability of perturbation theory. Nevertheless, they still lead to the same universal quantum continuum limit and show excellent scaling behavior. By using the constraint angle action we gain new insight into the Berezinskii-Kosterlitz-Thouless phase transition of the 2d XY model. This phase transition is of special interest since it is one of the few examples of a phase transition beyond second order. It is of infinite order and therefore an essential phase transition. In particular, we observe an excellent scaling behavior of the helicity modulus, which characterizes this phase transition. We also observe that the mechanism of (un)binding vortex--anti-vortex pairs follows the usual pattern, although free vortices do not require any energy in the formulation of the 2d XY model using the constraint angle action.
Magnetic Nanorods Confined in a Lamellar Lyotropic Phase
Keevin Béneut; Doru Constantin; Patrick Davidson; Arnaud Dessombz; Corinne Chanéac
2015-04-11T23:59:59.000Z
The dilute lamellar phase of the nonionic surfactant C$_{12}$EO$_5$ was doped with goethite (iron oxide) nanorods up to a fraction of 5 vol. %. The interaction between the inclusions and the host phase was studied by polarized optical microscopy (with or without an applied magnetic field) and by small-angle X-ray scattering. We find that, when the orientation of the nanorods is modified using the magnetic field, the texture of the lamellar phase changes accordingly; one can thus induce a homeotropic-planar reorientation transition. On the other hand, the lamellar phase induces an attractive interaction between the nanorods. In more concentrated lamellar phases (under stronger confinement) the particles form aggregates. This behavior is not encountered for a similar system doped with spherical particles, emphasizing the role of particle shape in the interaction between doping particles and the host phase.
Singh, Rameswar, E-mail: rameswar.singh@lpp.polytechnique.fr [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India) [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India); Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Brunner, S. [CRPP, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)] [CRPP, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Ganesh, R. [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India)] [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India); Jenko, F. [Max-Planck-Institut fur Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)] [Max-Planck-Institut fur Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)
2014-03-15T23:59:59.000Z
This paper presents effects of finite ballooning angles on linear ion temperature gradient (ITG) driven mode and associated heat and momentum flux in Gyrokinetic flux tube simulation GENE. It is found that zero ballooning angle is not always the one at which the linear growth rate is maximum. The ITG mode acquires a short wavelength (SW) branch (k{sub ?}?{sub i}?>?1) when growth rates maximized over all ballooning angles are considered. However, the SW branch disappears on reducing temperature gradient showing characteristics of zero ballooning angle SWITG in case of extremely high temperature gradient. Associated heat flux is even with respect to ballooning angle and maximizes at nonzero ballooning angle while the parallel momentum flux is odd with respect to the ballooning angle.
Wake angle for surface gravity waves on a finite depth fluid
Pethiyagoda, Ravindra; Moroney, Timothy J
2015-01-01T23:59:59.000Z
Linear water wave theory suggests that wave patterns caused by a steadily moving disturbance are contained within a wedge whose half-angle depends on the depth-based Froude number $F_H$. For the problem of flow past an axisymmetric pressure distribution in a finite-depth channel, we report on the apparent angle of the wake, which is the angle of maximum peaks. For moderately deep channels, the dependence of the apparent wake angle on the Froude number is very different to the wedge angle, and varies smoothly as $F_H$ passes through the critical value $F_H=1$. For shallow water, the two angles tend to follow each other more closely, which leads to very large apparent wake angles for certain regimes.
Grate, Jay W.; Dehoff, Karl J.; Warner, Marvin G.; Pittman, Jonathan W.; Wietsma, Thomas W.; Zhang, Changyong; Oostrom, Martinus
2012-02-24T23:59:59.000Z
The use of air-water, {Theta}{sub wa}, or air-liquid contact angles is customary in surface science, while oil-water contact angles {Theta}{sub ow}, are of paramount importance in subsurface multiphase flow phenomena including petroleum reocovery, nonaqueous phase liquid fate and transport, and geological carbon sequestration. In this paper we determine both the air-water and oil-water contact angles of silica surfaces modified with a diverse selection of silanes, using hexadecane as the oil. The silanes included alkylsilanes, alkylarylsilanes, and silanes with alkyl or aryl groups that are functionalized with heteroatoms such as N, O, and S. These silanes yielded surfaces with wettabilities from water-wet to oil wet, including specific silanized surfaces functionalized with heteroatoms that yield intermediate wet surfaces. The oil-water contact angles for clean and silanized surfaces, excluding one partially fluorinated surface, correlate linearly with air-water contact angles with a slope of 1.41 (R = 0.981, n = 13). These data were used to examine a previously untested theoretical treatment relating air-water and oil-water contact angles in terms of fluid interfacial energies. Plotting the cosines of these contact angles against one another, we obtain a linear relationship in excellent agreement with the theoretical treatment; the data fit cos {Theta}{sub ow} = 0.667 cos {Theta}{sub ow} + 0.384 (R = 0.981, n = 13), intercepting cos {Theta}{sub ow} = -1 at -0.284. The theoretical slope, based on the fluid interfacial tensions {Theta}{sub wa}, {Theta}{sub ow}, and {Theta}{sub oa}, is 0.67. We also demonstrate how silanes can be used to alter the wettability of the interior of a pore network micromodel device constructed in silicon/silica with a glass cover plate. Such micromodels are used to study multiphase flow phenomena. The contact angle of the resulting interior was determined in situ. An intermediate wet micromodel gave a contact angle in excellent agreement with that obtained on an open planar silica surface using the same silane.
A Phase-Field Model for Phase Transformations in Glass-Forming Alloys
Wang, Tao; Napolitano, Ralph E.
2012-03-24T23:59:59.000Z
A phase-field model is proposed for phase transformations in glass-forming alloys. The glass transition is introduced as a structural relaxation, and the competition between the glass and crystalline phases is investigated. The simulations are performed for Cu-Zr alloys, employing thermodynamic and kinetic parameters derived from reported thermodynamic modeling and molecular dynamics simulation results,[1–3] respectively. Four distinct phase fields are treated with a multi-phase-field approach, representing the liquid/glass, Cu10Zr7, CuZr, and CuZr2 phases. In addition, a continuum-field method is applied to the liquid to accommodate the liquid–glass transformation. The combined phase-field approach is used to investigate the glass formation tendency, and critical cooling rates are estimated and compared with the reported experimental values.
Elastic nucleon scattering at small angles at LHC energies
S. V. Goloskokov; S. P. Kuleshov; O. V. Selyugin
1997-07-02T23:59:59.000Z
Predictions of the elastic proton-proton cross sections at energies of LHC are calculate on the base of the high energy dynamical model. The growth of $ds/dt$ at fixed transfer momenta are shown. The form of eikonal of elastic hadron scattering at super high energies is discussed.
The MOLLER Experiment: An Ultra-Precise Measurement of the Weak Mixing Angle Using Møller Scattering
MOLLER Collaboration; J. Benesch; P. Brindza; R. D. Carlini; J-P. Chen; E. Chudakov; S. Covrig; M. M. Dalton; A. Deur; D. Gaskell; A. Gavalya; J. Gomez; D. W. Higinbotham; C. Keppel; D. Meekins; R. Michaels; B. Moffit; Y. Roblin; R. Suleiman; R. Wines; B. Wojtsekhowski; G. Cates; D. Crabb; D. Day; K. Gnanvo; D. Keller; N. Liyanage; V. V. Nelyubin; H. Nguyen; B. Norum; K. Paschke; V. Sulkosky; J. Zhang; X. Zheng; J. Birchall; P. Blunden; M. T. W. Gericke; W. R. Falk; L. Lee; J. Mammei; S. A. Page; W. T. H. van Oers; K. Dehmelt; A. Deshpande; N. Feege; T. K. Hemmick; K. S. Kumar; T. Kutz; R. Miskimen; M. J. Ramsey-Musolf; S. Riordan; N. Hirlinger Saylor; J. Bessuille; E. Ihloff; J. Kelsey; S. Kowalski; R. Silwal; G. De Cataldo; R. De Leo; D. Di Bari; L. Lagamba; E. NappiV. Bellini; F. Mammoliti; F. Noto; M. L. Sperduto; C. M. Sutera; P. Cole; T. A. Forest; M. Khandekar; D. McNulty; K. Aulenbacher; S. Baunack; F. Maas; V. Tioukine; R. Gilman; K. Myers; R. Ransome; A. Tadepalli; R. Beniniwattha; R. Holmes; P. Souder; D. S. Armstrong; T. D. Averett; W. Deconinck; W. Duvall; A. Lee; M. L. Pitt; J. A. Dunne; D. Dutta; L. El Fassi; F. De Persio; F. Meddi; G. M. Urciuoli; E. Cisbani; C. Fanelli; F. Garibaldi; K. Johnston; N. Simicevic; S. Wells; P. M. King; J. Roche; J. Arrington; P. E. Reimer; G. Franklin; B. Quinn; A. Ahmidouch; S. Danagoulian; O. Glamazdin; R. Pomatsalyuk; R. Mammei; J. W. Martin; T. Holmstrom; J. Erler; Yu. G. Kolomensky; J. Napolitano; K. A. Aniol; W. D. Ramsay; E. Korkmaz; D. T. Spayde; F. Benmokhtar; A. Del Dotto; R. Perrino; S. Barkanova; A. Aleksejevs; J. Singh
2014-12-03T23:59:59.000Z
The physics case and an experimental overview of the MOLLER (Measurement Of a Lepton Lepton Electroweak Reaction) experiment at the 12 GeV upgraded Jefferson Lab are presented. A highlight of the Fundamental Symmetries subfield of the 2007 NSAC Long Range Plan was the SLAC E158 measurement of the parity-violating asymmetry $A_{PV}$ in polarized electron-electron (M{\\o}ller) scattering. The proposed MOLLER experiment will improve on this result by a factor of five, yielding the most precise measurement of the weak mixing angle at low or high energy anticipated over the next decade. This new result would be sensitive to the interference of the electromagnetic amplitude with new neutral current amplitudes as weak as $\\sim 10^{-3}\\cdot G_F$ from as yet undiscovered dynamics beyond the Standard Model. The resulting discovery reach is unmatched by any proposed experiment measuring a flavor- and CP-conserving process over the next decade, and yields a unique window to new physics at MeV and multi-TeV scales, complementary to direct searches at high energy colliders such as the Large Hadron Collider (LHC). The experiment takes advantage of the unique opportunity provided by the upgraded electron beam energy, luminosity, and stability at Jefferson Laboratory and the extensive experience accumulated in the community after a round of recent successfully completed parity-violating electron scattering experiments
Dynamical tunneling and control
Srihari Keshavamurthy
2011-07-25T23:59:59.000Z
This article summarizes the recent work on the influence of dynamical tunneling on the control of quantum systems. Specifically, two examples are discussed. In the first, it is shown that the bichromatic control of tunneling in a driven double well system is hampered by the phenomenon of chaos-assisted tunneling. The bichromatic control landscape exhibits several regions indicating lack of control with every such region involving chaos-assisted tunneling. The second example illustrates the failure of controlling the dissociation dynamics of a driven Morse oscillator due to the phenomenon of resonance-assisted tunneling. In particular, attempts to control the dissociation dynamics by rebuilding local phase space barriers are foiled due to resonance-assisted tunneling.
Bai, Sen; Li, Guangjun; Wang, Maojie; Jiang, Qinfeng; Zhang, Yingjie [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China); Wei, Yuquan, E-mail: yuquawei@vip.sina.com [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China)
2013-07-01T23:59:59.000Z
The purpose of this study was to investigate the effect of multileaf collimator (MLC) leaf position, collimator rotation angle, and accelerator gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma. To compare dosimetric differences between the simulating plans and the clinical plans with evaluation parameters, 6 patients with nasopharyngeal carcinoma were selected for simulation of systematic and random MLC leaf position errors, collimator rotation angle errors, and accelerator gantry rotation angle errors. There was a high sensitivity to dose distribution for systematic MLC leaf position errors in response to field size. When the systematic MLC position errors were 0.5, 1, and 2 mm, respectively, the maximum values of the mean dose deviation, observed in parotid glands, were 4.63%, 8.69%, and 18.32%, respectively. The dosimetric effect was comparatively small for systematic MLC shift errors. For random MLC errors up to 2 mm and collimator and gantry rotation angle errors up to 0.5°, the dosimetric effect was negligible. We suggest that quality control be regularly conducted for MLC leaves, so as to ensure that systematic MLC leaf position errors are within 0.5 mm. Because the dosimetric effect of 0.5° collimator and gantry rotation angle errors is negligible, it can be concluded that setting a proper threshold for allowed errors of collimator and gantry rotation angle may increase treatment efficacy and reduce treatment time.
Goddard III, William A.
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 104, NO. B7, PAGES 15,005-15,023, JULY 10, 1999 Dynamics by the American GeophysicalUnion. Paper number 1999JB900065. 0148-0227/ 99/ 1999JB900065509.00 The large
Gas phase 129Xe NMR imaging and spectroscopy
Kaiser, Lana G.
2010-01-01T23:59:59.000Z
5 l l Dynamic NMR microscopy of gas phase Poiseuille flowmetal vapors and noble gases can be used to efficientlypolarize the nuclei ofthe noble-gas atoms. As a result, the
Phase-equilibrium-mediated assembly of colloidal nanoparticles
Kwon, Seok Joon
2013-01-01T23:59:59.000Z
Colloidal dispersion of nanoparticles (CNPs) has interesting properties both in terms of fundamental studies and industrials applications. Particular focus on the phase equilibrium and separation dynamics of CNPs has been ...
Method and apparatus for controlling pitch and flap angles of a wind turbine
Deering, Kenneth J. (Seattle, WA); Wohlwend, Keith P. (Issaquah, WA)
2009-05-12T23:59:59.000Z
A wind turbine with improved response to wind conditions is provided. Blade flap angle motion is accompanied by a change in pitch angle by an amount defining a pitch/flap coupling ratio. The coupling ratio is non-constant as a function of a flap angle and is preferably a substantially continuous, non-linear function of flap angle. The non-constant coupling ratio can be provided by mechanical systems such as a series of linkages or by configuring electronic or other control systems and/or angle sensors. A link with a movable proximal end advantageously is part of the mechanical system. The system can provide relatively large coupling ratios and relatively large rates of coupling ratio changes especially for near-feather pitches and low flap angles.
New Mixing Angles in the Left-Right Symmetric Model
Kokado, Akira
2015-01-01T23:59:59.000Z
The left-right symmetric model is characterized by three mixing angles $\\theta _{12}, \\theta_{23}, \\theta_{13}$ between three gauge fields $B_\\mu , W^3_{L\\mu }, W^3_{R\\mu }$, which produce mass eigenstates $A_{\\mu }, Z_{\\mu }, Z'_{\\mu }$. The mass matrix can be diagonal if $\\tan{\\theta _{23}}=-\\sin{\\theta _{12}}\\sin{\\theta_{13}}/\\cos{\\theta_{12}} + O(\\delta )$ , where $\\delta $ is an infinitesimally small parameter associated with the spontaneously broken left-right symmetry. Taking the limit $\\delta \\to 0$, then introducing new variables $s'=\\sin{\\theta _{12}}\\cos{\\theta _{13}}$ and $c'=\\cos{\\theta _{12}}/\\cos{\\theta _{23}}$ with $s'^2 + c'^2 =1$, we show that all gauge boson masses can be expressed in terms of $s', c'$, namely, $M_W =$ 37.3 $/s'$ [Gev/$c^2$] and $M_Z/M_W=1/c'$. Coupling strengths between the proton and the $Z$ boson as well as those of neutrinos and $Z$ can be shown to be expressed by $s' , c'$. All results are completely the same as those of the Weinberg-Salam theory with $SU(2)_{L}\\times ...
Azimuthal angle dependence of dijet production in unpolarized hadron scattering
Lu Zhun; Schmidt, Ivan [Departamento de Fisica, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile) and Center of Subatomic Physics, Valparaiso (Chile)
2008-08-01T23:59:59.000Z
We study the azimuthal angular dependence of back-to-back dijet production in unpolarized hadron scattering H{sub A}+H{sub B}{yields}J{sub 1}+J{sub 2}+X, arising from the product of two Boer-Mulders functions, which describe the transverse spin distribution of quarks inside an unpolarized hadron. We find that when the dijet is of two identical quarks (J{sub q}+J{sub q}) or a quark-antiquark pair (J{sub q}+J{sub q}), there is a cos{delta}{phi} angular dependence of the dijet, with {delta}{phi}={phi}{sub 1}-{phi}{sub 2}, and {phi}{sub 1} and {phi}{sub 2} are the azimuthal angles of the two individual jets. In the case of J{sub q}+J{sub q} production, we find that there is a color factor enhancement in the gluonic cross section, compared with the result from the standard generalized parton model. We estimate the cos{delta}{phi} asymmetry of dijet production at RHIC, showing that the color factor enhancement in the angular dependence of J{sub q}+J{sub q} production will reverse the sign of the asymmetry.
Small angle elastic scattering of protons off of spinless nuclei
Ling, A.G.
1988-07-01T23:59:59.000Z
Elastic differential cross sections and analyzing powers for 800 MeV protons incident on /sup 12/C, /sup 40/Ca, and /sup 208/Pb in the momentum transfer range 20 MeV/c < q < 130 MeV/c have been measured. The data was taken with the High Resolution Spectrometer (HRS) at the Los Alamos Meson Physics Facility. Special delay-line drift chambers with dead regions for the beam to pass through them were used to obtain the data. Through the interference of the Coulomb and nuclear contributions to the differential cross section in the small angle region, the ratio of the real to imaginary part of the forward nuclear amplitude ..cap alpha../sub n/(0) = Ref/sub n/(0)/Imf/sub n/(0) is extracted. The importance of knowing this quantity at lower energies in order to study the differences between relativistic and non-relativistic scattering theories is discussed. 130 refs., 60 figs., 12 tabs.
Angle stations in or for endless conveyor belts
Steel, Alan (Glasgow, GB6)
1987-04-07T23:59:59.000Z
In an angle station for an endless conveyor belt, there are presented to each incoming run of the belt stationary curved guide members (18, 19) of the shape of a major segment of a right-circular cylinder and having in the part-cylindrical portion (16 or 17) thereof rectangular openings (15) arranged in parallel and helical paths and through which project small freely-rotatable rollers (14), the continuously-changing segments of the curved surfaces of which projecting through said openings (15) are in attitude to change the direction of travel of the belt (13) through 90.degree. during passage of the belt about the part-cylindrical portion (16 or 17) of the guide member (18 or 19). The rectangular openings (15) are arranged with their longer edges lengthwise of the diagonals representing the mean of the helix but with those of a plurality of the rows nearest to each end of the part-cylindrical portion (16 or 17) slightly out of axial symmetry with said diagonals, being slightly inclined in a direction about the intersections (40) of the diagonals of the main portion of the openings, to provide a "toe-in" attitude in relation to the line of run of the endless conveyor belt.
Optimum angle for side injection of electrons into linear plasma wakefields
Lotov, Konstantin V
2012-01-01T23:59:59.000Z
A unified model of electron penetration into linear plasma wakefields is formulated and studied. The optimum angle for side injection of electrons is found. At smaller angles, all electrons are reflected radially. At larger angles, electrons enter the wakefield with superfluous transverse momentum that is unfavorable for trapping. Separation of incident electrons into penetrated and reflected fractions occur in the outer region of the wakefield at some "reflection" radius that depends on the electron energy.
A study of contact angles in porous solids using heat pipes
Collins, Richard Clark
1971-01-01T23:59:59.000Z
A STUDY OF CONTACT ANGLES IN FOROUS SOLIDS USING HEAT PIPES A Thesis by RICHARD CLARK COLLINS Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1971... Major Subject: Mechanical Engineering A STUDY OF CONTACT ANGLES IN POROUS SOLIDS USING HEAT PIPES A Thesis RICHARD CLARK COLLINS Approved as to style and content by; (~(, (Head of Department) (Member) May 1971 ABSTRACT A Study of Contact Angles...
Nguyen, Hung T. [BioMaPS Institute for Quantitative Biology, Rutgers University, Piscataway, New Jersey 08854 (United States); Pabit, Suzette A.; Meisburger, Steve P.; Pollack, Lois [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Case, David A., E-mail: case@biomaps.rutgers.edu [BioMaPS Institute for Quantitative Biology, Rutgers University, Piscataway, New Jersey 08854 (United States); Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854 (United States)
2014-12-14T23:59:59.000Z
A new method is introduced to compute X-ray solution scattering profiles from atomic models of macromolecules. The three-dimensional version of the Reference Interaction Site Model (RISM) from liquid-state statistical mechanics is employed to compute the solvent distribution around the solute, including both water and ions. X-ray scattering profiles are computed from this distribution together with the solute geometry. We describe an efficient procedure for performing this calculation employing a Lebedev grid for the angular averaging. The intensity profiles (which involve no adjustable parameters) match experiment and molecular dynamics simulations up to wide angle for two proteins (lysozyme and myoglobin) in water, as well as the small-angle profiles for a dozen biomolecules taken from the BioIsis.net database. The RISM model is especially well-suited for studies of nucleic acids in salt solution. Use of fiber-diffraction models for the structure of duplex DNA in solution yields close agreement with the observed scattering profiles in both the small and wide angle scattering (SAXS and WAXS) regimes. In addition, computed profiles of anomalous SAXS signals (for Rb{sup +} and Sr{sup 2+}) emphasize the ionic contribution to scattering and are in reasonable agreement with experiment. In cases where an absolute calibration of the experimental data at q = 0 is available, one can extract a count of the excess number of waters and ions; computed values depend on the closure that is assumed in the solution of the Ornstein–Zernike equations, with results from the Kovalenko–Hirata closure being closest to experiment for the cases studied here.
Cheung, Y.W.; Stein, R.S. (Univ. of Massachusetts, Amherst, MA (United States). Dept. of Polymer Science and Engineering); Lin, J.S.; Wignall, G.D. (Oak Ridge National Lab., Oak Ridge, TN (United States))
1994-04-25T23:59:59.000Z
Crystalline morphologies of poly([epsilon]-caprolactone) (PCL) and polycarbonate (PC) blends were probed with small-angle X-ray scattering (SAXS) and small-angle light scattering (SALS). Quantitative SAXS analysis suggested that random mixing of PCL and PC lamellae occurred in the semicrystalline/semicrystalline state. Two distinct regions of incorporation were identified in the semicrystalline/amorphous state. It was found that PCL was rejected from the PC interlamellar region in the PCL-rich blends. In contrast, PCL was incorporated into the amorphous phase between the crystalline lamellae in the PC-rich blends. This transition from interlamellar exclusion to interlamellar inclusion may be related to the glass transition temperatures or the mobility of the blends. It is proposed that the mode of incorporation or exclusion is governed by the competition between entropy and diffusion. Additionally, SALS coupled with optical microscopy indicated that PC is an effective nucleating agent for PCL crystallization as manifested by the reduction of PCL spherulitic size with the addition of PC.
Rapid granular flows on a rough incline: phase diagram, gas transition, and effects of air drag
Tamas Borzsonyi; Robert E. Ecke
2006-11-16T23:59:59.000Z
We report experiments on the overall phase diagram of granular flows on an incline with emphasis on high inclination angles where the mean layer velocity approaches the terminal velocity of a single particle free falling in air. The granular flow was characterized by measurements of the surface velocity, the average layer height, and the mean density of the layer as functions of the hopper opening, the plane inclination angle and the downstream distance x of the flow. At high inclination angles the flow does not reach an x-invariant steady state over the length of the inclined plane. For low volume flow rates, a transition was detected between dense and very dilute (gas) flow regimes. We show using a vacuum flow channel that air did not qualitatively change the phase diagram and did not quantitatively modify mean flow velocities of the granular layer except for small changes in the very dilute gas-like phase.
Richard Beyer; Markus Franke; Hans Joachim Schöpe; Eckhard Bartsch; Thomas Palberg
2015-05-11T23:59:59.000Z
Hard sphere suspensions are well recognized model systems of statistical physics and soft condensed matter. We here investigate the temporal evolution of the immediate environment of nucleating and growing crystals and/or their global scale distribution using time resolved Small Angle Light Scattering (SALS). Simultaneously performed Bragg scattering (BS) measurements provide an accurate temporal gauging of the sequence of events. We apply this approach to studies of re-crystallization in several different shear molten hard sphere and attractive hard sphere samples with the focus being on the diversity of observable signal shapes and their change in time. We demonstrate that depending on the preparation conditions different processes occur on length scales larger than the structural scale which significantly influence both the crystallization kinetics and the final micro-structure. By careful analysis of the SALS signal evolution and by comparing different suggestions for small angle signal shapes to our data we can for most cases identify the processes leading to the observed signals. These include phase contrast form factor scattering from depletion zones during formation and overlap as well as during gelation, amplitude contrast form factor scattering by more transparent crystals, and structure factor scattering from late stage inter-crystallite ordering. The large variety of different small angle signals thus in principle contains valuable information complementary to that gained from Bragg scattering or microscopy. Our comparison, however, also shows that further refinement and adaptation of the theoretical expressions to the sample specific boundary conditions is desired for a quantitative kinetic analysis of micro-structural evolution.
Konstantine Zelator
2012-03-12T23:59:59.000Z
In one of the three 2010/2011 issues of the journal 'MathematicalSpectrum', this author gave a three-parameter description of the entire set of integral triangles(i.e. triangles with integer side lengths)and with a 120 degree angle.This entire set expressed as a union of four families, see reference[5]. In this work we describe, in terms of three parameters again, the set of all integral with a 120 degree angle, and whose bisectors of their 120 degree angles; is also of integral length. To do so, we use the well known historic theorem of Ptolemy for cyclic quadrilaterals, in conjunction with the general positive integer solution of the equation, 1/z=1/x +1/y; and of course in combination with the parametric description of the set of integral triangles with a 120 degree angle mentioned above,The final results of this paper are found in section8.
Tilt and Rotation Angles of a Transmembrane Model Peptide as Studied by Fluorescence Spectroscopy
Gelb, Michael
concentrations of cholesterol, small changes in tilt angle were observed as response to hydro- phobic mismatch). Similar results have been re- ported for other small natural membrane peptides
Acoustic And Elastic Reverse-Time Migration: Novel Angle-Domain Imaging Conditions And Applications
Yan, Rui
2013-01-01T23:59:59.000Z
S. Wu, 1996, Prestack depth migration with acoustic screenN. D. , 1983, Iterative depth migration by backward time1355. ——–, 2003, Prestack depth migration in angle-domain
CrowdPhase: crowdsourcing the phase problem
Jorda, Julien; Sawaya, Michael R. [Institute for Genomics and Proteomics, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); Yeates, Todd O., E-mail: yeates@mbi.ucla.edu [Institute for Genomics and Proteomics, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); Molecular Biology Institute, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); University of California, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States)
2014-06-01T23:59:59.000Z
The idea of attacking the phase problem by crowdsourcing is introduced. Using an interactive, multi-player, web-based system, participants work simultaneously to select phase sets that correspond to better electron-density maps in order to solve low-resolution phasing problems. The human mind innately excels at some complex tasks that are difficult to solve using computers alone. For complex problems amenable to parallelization, strategies can be developed to exploit human intelligence in a collective form: such approaches are sometimes referred to as ‘crowdsourcing’. Here, a first attempt at a crowdsourced approach for low-resolution ab initio phasing in macromolecular crystallography is proposed. A collaborative online game named CrowdPhase was designed, which relies on a human-powered genetic algorithm, where players control the selection mechanism during the evolutionary process. The algorithm starts from a population of ‘individuals’, each with a random genetic makeup, in this case a map prepared from a random set of phases, and tries to cause the population to evolve towards individuals with better phases based on Darwinian survival of the fittest. Players apply their pattern-recognition capabilities to evaluate the electron-density maps generated from these sets of phases and to select the fittest individuals. A user-friendly interface, a training stage and a competitive scoring system foster a network of well trained players who can guide the genetic algorithm towards better solutions from generation to generation via gameplay. CrowdPhase was applied to two synthetic low-resolution phasing puzzles and it was shown that players could successfully obtain phase sets in the 30° phase error range and corresponding molecular envelopes showing agreement with the low-resolution models. The successful preliminary studies suggest that with further development the crowdsourcing approach could fill a gap in current crystallographic methods by making it possible to extract meaningful information in cases where limited resolution might otherwise prevent initial phasing.
Geometric phases of water waves
Francesco Fedele
2014-08-08T23:59:59.000Z
Recently, Banner et al. (2014) highlighted a new fundamental property of open ocean wave groups, the so-called crest slowdown. For linear narrowband waves, this is related to the geometric and dynamical phase velocities $U_d$ and $U_g$ associated with the parallel transport through the principal fiber bundle of the wave motion with $\\mathit{U}(1)$ symmetry. The theoretical predictions are shown to be in fair agreement with ocean field observations, from which the average crest speed $c=U_d+U_g$ with $c/U_d\\approx0.8$ and $U_{g}/U_d\\approx-0.2$.
Economic Recovery of Oil Trapped at Fan Margins Using Hig Angle Wells Multiple Hydraulic Fractures
Laue, M.L.
1997-11-21T23:59:59.000Z
The Yowlumne field is a giant field in the southern San Joaquin basin, Kern County, California. It is a deep (13,000 ft) waterflood operation that produces from the Miocene- aged Stevens Sand. The reservoir is interpreted as a layered, fan-shaped, prograding turbidite complex containing several lobe-shaped sand bodies that represent distinct flow units. A high ultimate recovery factor is expected, yet significant quantities of undrained oil remain at the fan margins. The fan margins are not economic to develop using vertical wells because of thinning pay, deteriorating rock quality, and depth. This project attempts to demonstrate the effectiveness of exploiting the northeast distal fan margin through the use of a high- angle well completed with multiple hydraulic- fracture treatments. A high-angle well offers greater pay exposure than can be achieved with a vertical well. Hydraulic-fracture treatments will establish vertical communication between thin interbedded layers and the wellbore. The equivalent production rate and reserves of three vertical wells are anticipated at a cost of approximately two vertical wells. The near-horizontal well penetrated the Yowlumne sand; a Stevens sand equivalent, in the distal fan margin in the northeast area of the field. The well was drilled in a predominately westerly direction towards the interior of the field, in the direction of improving rock quality. Drilling and completion operations proved to be very challenging, leading to a number of adjustments to original plans. Hole conditions resulted in obtaining less core material than desired and setting intermediate casing 1200 ft too high. The 7 in. production liner stuck 1000 ft off bottom, requiring a 5 in. liner to be run the rest of the way. The cement job on the 5 in. liner resulted in a very poor bond, which precluded one of three hydraulic fracture treatments originally planned for the well. Openhole logs confirmed most expectations going into the project about basic rock properties: the formation was shaly with low porosities, and water saturations were in line with expectations, including the presence of some intervals swept out by the waterflood. High water saturations at the bottom of the well eliminated one of the originally planned hydraulic fracture treatments. Although porosities proved to be low, they were more uniform across the formation than expected. Permeabilities of the various intervals continue to be evaluated, but appear to be better than expected from the porosity log model derived in Budget Period One. The well was perforated in all pay sections behind the 5 in. liner. Production rates and phases agree nicely with log calculations, fractional flow calculations, and an analytical technique used to predict the rate performance of the well.
In-phase and anti-phase synchronization in noisy Hodgkin-Huxley neurons
Schmid, Gerhard; Hanggi, Peter
2013-01-01T23:59:59.000Z
We numerically investigate the influence of intrinsic channel noise on the dynamical response of delay-coupling in neuronal systems. The stochastic dynamics of the spiking is modeled within a stochastic modification of the standard Hodgkin-Huxley model wherein the delay-coupling accounts for the finite propagation time of an action potential along the neuronal axon. We quantify this delay-coupling of the Pyragas-type in terms of the difference between corresponding presynaptic and postsynaptic membrane potentials. In case of a single neuron we analyze the spiking activity in presence of an autaptic feedback loop. With vanishing channel noise the interspike interval increases with increasing delay time. For an elementary neuronal network consisting of two coupled neurons we detect characteristic stochastic synchronization patterns which exhibit multiple phase-flip bifurcations: The phase-flip bifurcations occur in form of alternate transitions from an in-phase spiking activity towards an anti-phase spiking act...
Small angle neutron scattering study of Linde 80 RPV welds
Wirth, B.D.; Odette, G.R.; Lucas, G.E. [Univ. of California, Santa Barbara, CA (United States). Dept. of Mechanical and Environmental Engineering; Pavinich, W.A. [Framatome Technologies Inc., Knoxville, TN (United States); Spooner, S.E. [Oak Ridge National Lab., TN (United States). Solid state Div.
1999-10-01T23:59:59.000Z
Small angle neutron scattering (SANS) results are presented for Linde 80 welds irradiated, as part of the B and W Owners Group Integrated Surveillance Program, at low fluxes (<10{sup 15} n/m{sup 2}-s) to fluences from 0.29 to 3.5 {times} 10{sup 23} n/m{sup 2} (E > 1 MeV) at irradiation temperatures from 276 to 292 C. The welds all contain about 0.6 Ni (all composition units are in wt.%), 0.009 to 0.18 P and 0.05 to 0.28 Cu. In the welds with significant amounts of copper (>0.2 Cu) the measured defect scattering cross sections were consistent with either: (a) copper rich precipitates (CRPs) alloyed with manganese and nickel; or (b) dominant CRP scattering, plus a weak contribution from so-called matrix defect features. Similar weak scattering was observed in a low copper (0.06 Cu) weld. The identity of matrix defect features cannot be determined from the SANS data alone, but the scattering is consistent with the presence of subnanometer vacancy cluster-solute complexes. The general character of the CRPs, and the trends in their number density, volume fraction and average radius as a function of fluence and irradiation temperature, are very similar to those observed in a wide range of pressure vessel-type steels irradiated in test reactors at intermediate to high flux. The SANS data in the surveillance welds is also in unity with: (a) thermodynamic-kinetic radiation enhanced diffusion models of CRP evolution; (b) mechanical property changes, including predictions of the correlations of the surveillance data base; and (c) an atomic scale, atom probe field ion microscopy study into the nanostructure-chemistry of a CRP.
Adaptive sparse polynomial chaos expansion based on least angle regression
Blatman, Geraud, E-mail: geraud.blatman@edf.f [Clermont Universite, IFMA, EA 3867, Laboratoire de Mecanique et Ingenieries, BP 10448, F-63000 Clermont-Ferrand (France); EDF R and D, Departement Materiaux et Mecanique des Composants, Site des Renardieres, 77250 Moret-sur-Loing cedex (France); Sudret, Bruno [Clermont Universite, IFMA, EA 3867, Laboratoire de Mecanique et Ingenieries, BP 10448, F-63000 Clermont-Ferrand (France); Phimeca Engineering, Centre d'Affaires du Zenith, 34 rue de Sarlieve, F-63800 Cournon d'Auvergne (France)
2011-03-20T23:59:59.000Z
Polynomial chaos (PC) expansions are used in stochastic finite element analysis to represent the random model response by a set of coefficients in a suitable (so-called polynomial chaos) basis. The number of terms to be computed grows dramatically with the size of the input random vector, which makes the computational cost of classical solution schemes (may it be intrusive (i.e. of Galerkin type) or non intrusive) unaffordable when the deterministic finite element model is expensive to evaluate. To address such problems, the paper describes a non intrusive method that builds a sparse PC expansion. First, an original strategy for truncating the PC expansions, based on hyperbolic index sets, is proposed. Then an adaptive algorithm based on least angle regression (LAR) is devised for automatically detecting the significant coefficients of the PC expansion. Beside the sparsity of the basis, the experimental design used at each step of the algorithm is systematically complemented in order to avoid the overfitting phenomenon. The accuracy of the PC metamodel is checked using an estimate inspired by statistical learning theory, namely the corrected leave-one-out error. As a consequence, a rather small number of PC terms are eventually retained (sparse representation), which may be obtained at a reduced computational cost compared to the classical 'full' PC approximation. The convergence of the algorithm is shown on an analytical function. Then the method is illustrated on three stochastic finite element problems. The first model features 10 input random variables, whereas the two others involve an input random field, which is discretized into 38 and 30 - 500 random variables, respectively.
Grassi, G. [Commissariat a l'Energie Atomique, CEA de Saclay, DM2S/SERMA/LENR, 91191, Gif-sur-Yvette (France)
2006-07-01T23:59:59.000Z
We present a non-linear space-angle two-level acceleration scheme for the method of the characteristics (MOC). To the fine level on which the MOC transport calculation is performed, we associate a more coarsely discretized phase space in which a low-order problem is solved as an acceleration step. Cross sections on the coarse level are obtained by a flux-volume homogenisation technique, which entails the non-linearity of the acceleration. Discontinuity factors per surface are introduced as additional degrees of freedom on the coarse level in order to ensure the equivalence of the heterogeneous and the homogenised problem. After each fine transport iteration, a low-order transport problem is iteratively solved on the homogenised grid. The solution of this problem is then used to correct the angular moments of the flux resulting from the previous free transport sweep. Numerical tests for a given benchmark have been performed. Results are discussed. (authors)
Terwilliger, Thomas C., E-mail: terwilliger@lanl.gov [Bioscience Division, Mail Stop M888, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2001-12-01T23:59:59.000Z
A map-likelihood function is described that can yield phase probabilities with very low model bias. The recently developed technique of maximum-likelihood density modification [Terwilliger (2000 ?), Acta Cryst. D56, 965–972] allows a calculation of phase probabilities based on the likelihood of the electron-density map to be carried out separately from the calculation of any prior phase probabilities. Here, it is shown that phase-probability distributions calculated from the map-likelihood function alone can be highly accurate and that they show minimal bias towards the phases used to initiate the calculation. Map-likelihood phase probabilities depend upon expected characteristics of the electron-density map, such as a defined solvent region and expected electron-density distributions within the solvent region and the region occupied by a macromolecule. In the simplest case, map-likelihood phase-probability distributions are largely based on the flatness of the solvent region. Though map-likelihood phases can be calculated without prior phase information, they are greatly enhanced by high-quality starting phases. This leads to the technique of prime-and-switch phasing for removing model bias. In prime-and-switch phasing, biased phases such as those from a model are used to prime or initiate map-likelihood phasing, then final phases are obtained from map-likelihood phasing alone. Map-likelihood phasing can be applied in cases with solvent content as low as 30%. Potential applications of map-likelihood phasing include unbiased phase calculation from molecular-replacement models, iterative model building, unbiased electron-density maps for cases where 2F{sub o} ? F{sub c} or ?{sub A}-weighted maps would currently be used, structure validation and ab initio phase determination from solvent masks, non-crystallographic symmetry or other knowledge about expected electron density.
Geometric phases for corotating elliptical vortex patches B. N. Shashikantha)
Shashikanth, Banavara N.
of an infinitely long rectilinear vortex tube of area A whose vorticity distribution is invariant along the lengthGeometric phases for corotating elliptical vortex patches B. N. Shashikantha) Control and Dynamical September 2000 We describe a geometric phase that arises when two elliptical vortex patches co- rotate
Nagle, John F.
neutron and X-ray scattering Jianjun Pan a, , Frederick A. Heberle a , Stephanie Tristram-Nagle b Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 378316100 Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 378316453, USA e Canadian
Small angle neutron scattering from single-wall carbon nanotube suspensions: evidence for isolated
Wang, Howard "Hao"
Small angle neutron scattering from single-wall carbon nanotube suspensions: evidence for isolated online: Abstract We report small angle neutron scattering (SANS) from dilute suspensions of purified University, Houghton, MI 49931, USA e NIST Center for Neutron Research, National Institute of Standards
Small angle neutron scattering on periodically deformed polymers A. R. Rennie
Boyer, Edmond
765 Small angle neutron scattering on periodically deformed polymers A. R. Rennie Institut für Phys-768 SEPTEMBRE 1984, 1. Introduction. Neutron scattering has proved a useful tool for the investigation of a wide time for a small angle neutron scattering spectrum is several minutes. Obser- vation on rapidly
High temperature furnaces for small and large angle neutron scattering of disordered materials
Boyer, Edmond
725 High temperature furnaces for small and large angle neutron scattering of disordered materials and small angle neutron scattering (SANS) experiments respectively. They are vacuum furnaces with a thin maintained in a tantalum box. In a neutron beam, the furnaces produce a very low scattering level (without
Small angle neutron scattering (SANS) under non-equilibrium conditions R. C. Oberthr
Boyer, Edmond
663 Small angle neutron scattering (SANS) under non-equilibrium conditions R. C. Oberthür Institut with the times obtained from quasi- elastic neutron and light scattering, which yield information about neutrons aux petits angles (DNPA) pour l'étude des systèmes hors d'équi- libre thermodynamique est
Kilpatrick, Peter K.
-Angle Neutron Scattering Keith L. Gawrys, George A. Blankenship, and Peter K. Kilpatrick* Department of ChemicalVed September 14, 2005. In Final Form: January 30, 2006 While small-angle neutron scattering (SANS) has proven to the scattering intensity curves were performed using the Guinier approximation, the Ornstein- Zernike (or Zimm
Wuttke, Joachim; Zamponi, Michaela [Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstraße 1, 85747 Garching (Germany)] [Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstraße 1, 85747 Garching (Germany)
2013-11-15T23:59:59.000Z
The resolution of neutron backscattering spectrometers deteriorates at small scattering angles where analyzers deviate from exact backscattering. By reducing the azimuth angle range of the analyzers, the resolution can be improved with little loss of peak intensity. Measurements at the spectrometer SPHERES are in excellent agreement with simulations, which proves the dominance of geometric effects.
Salt-Dependent Compaction of Di-and Trinucleosomes Studied by Small-Angle Neutron Scattering
Langowski, Jörg
Salt-Dependent Compaction of Di- and Trinucleosomes Studied by Small-Angle Neutron Scattering, Germany, and Institut Laue-Langevin Grenoble, F-38042 Grenoble, France ABSTRACT Using small-angle neutron scattering (SANS), we have measured the salt-dependent static structure factor of di- and trinucleosomes from
29 Nov 2001 A. Bacchetta -Fragmentation to probe transversity 31 Hadron pair azimuthal angle
1 29 Nov 2001 A. Bacchetta - Fragmentation to probe transversity 31 Hadron pair azimuthal angle 29 Nov 2001 A. Bacchetta - Fragmentation to probe transversity 32 Center of mass angle hadron decay plane Center of mass direction in lab frame Center of mass frame R #12;2 29 Nov 2001 A. Bacchetta
Adhesion and Anisotropic Friction Enhancements of Angled Heterogeneous Micro-Fiber Arrays with
Goldstein, Seth Copen
in a synthetic dry angled fibrillar adhesive sample (spatula tip fiber sample). The direction dependent frictionAdhesion and Anisotropic Friction Enhancements of Angled Heterogeneous Micro-Fiber Arrays and spatula shaped tips via dipping. These fibers are characterized for adhesion and friction and compared
Factors that control the angle of shear bands in geodynamic numerical models of brittle deformation
Kaus, Boris
timescales typically use a pressure-dependent (Mohr Coulomb or DruckerPrager) plastic flow law to simulate University of Southern California, Los Angeles, USA a b s t r a c ta r t i c l e i n f o Article history work suggest that both Roscoe (45°), Coulomb angles (45+/-/2, where is the angle of internal friction
Performing fish counts with a wide-angle camera, a promising approach reducing divers' limitations
Borges, Rita
Performing fish counts with a wide-angle camera, a promising approach reducing divers' limitations Keywords: Fish surveys Underwater video Underwater visual census Wide-angle camera Visual standardised methods for census of reef fishes have long been used in fisheries management and biolog- ical surveys
Carlson, Erica
Thermoelectric figure of merit as a function of carrier propagation angle in semiconducting;Thermoelectric figure of merit as a function of carrier propagation angle in semiconducting superlattices Shuo a fruitful approach for enhancing the figure of merit, ZT, of thermoelectric materials. Generally
Heteronuclear Recoupling in Solid-State Magic-Angle-Spinning NMR via Overtone Irradiation
Frydman, Lucio
Heteronuclear Recoupling in Solid-State Magic-Angle-Spinning NMR via Overtone Irradiation Sungsool undergoing magic-angle- spinning (MAS) is introduced, based on the overtone irradiation of one of the coupled nuclei. It is shown that when I is a quadrupole, for instance 14N, irradiating this spin at a multiple
Shogo Tanimura
2015-04-06T23:59:59.000Z
The uncertainty relation between angle and orbital angular momentum had not been formulated in a similar form as the uncertainty relation between position and linear momentum because the angle variable is not represented by a quantum mechanical self-adjoint operator. Instead of the angle variable operator, we introduce the complex position operator $ \\hat{Z} = \\hat{x}+i \\hat{y} $ and interpret the order parameter $ \\mu = \\langle \\hat{Z} \\rangle / \\sqrt{ \\langle \\hat{Z}^\\dagger \\hat{Z} \\rangle} $ as a measure of certainty of the angle distribution. We prove the relation between the uncertainty of angular momentum and the angle order parameter. We prove also its generalizations and discuss experimental methods for testing these relations.
Analyzing intramolecular dynamics by Fast Lyapunov Indicators
Elena Shchekinova; Cristel Chandre; Yueheng Lan; Turgay Uzer
2009-04-23T23:59:59.000Z
We report an analysis of intramolecular dynamics of the highly excited planar carbonyl sulfide (OCS) below and at the dissociation threshold by the Fast Lyapunov Indicator (FLI) method. By mapping out the variety of dynamical regimes in the phase space of this molecule, we obtain the degree of regularity of the system versus its energy. We combine this stability analysis with a periodic orbit search, which yields a family of elliptic periodic orbits in the regular part of phase space an a family of in-phase collinear hyperbolic orbits associated with the chaotic regime.
Biosystem Dynamics & Design | EMSL
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Dynamics & Design Overview Atmospheric Aerosol Systems Biosystem Dynamics & Design Energy Materials & Processes Terrestrial & Subsurface Ecosystems Biosystem Dynamics &...
Digital quadrature phase detection
Smith, James A. (Idaho Falls, ID); Johnson, John A. (Idaho Falls, ID)
1992-01-01T23:59:59.000Z
A system for detecting the phase of a frequency of phase modulated signal that includes digital quadrature sampling of the frequency or phase modulated signal at two times that are one quarter of a cycle of a reference signal apart, determination of the arctangent of the ratio of a first sampling of the frequency or phase modulated signal to the second sampling of the frequency or phase modulated signal, and a determination of quadrant in which the phase determination is increased by 2.pi. when the quadrant changes from the first quadrant to the fourth quadrant and decreased by 2.pi. when the quadrant changes from the fourth quadrant to the first quadrant whereby the absolute phase of the frequency or phase modulated signal can be determined using an arbitrary reference convention.
Digital quadrature phase detection
Smith, J.A.; Johnson, J.A.
1992-05-26T23:59:59.000Z
A system for detecting the phase of a frequency or phase modulated signal that includes digital quadrature sampling of the frequency or phase modulated signal at two times that are one quarter of a cycle of a reference signal apart, determination of the arctangent of the ratio of a first sampling of the frequency or phase modulated signal to the second sampling of the frequency or phase modulated signal, and a determination of quadrant in which the phase determination is increased by 2[pi] when the quadrant changes from the first quadrant to the fourth quadrant and decreased by 2[pi] when the quadrant changes from the fourth quadrant to the first quadrant whereby the absolute phase of the frequency or phase modulated signal can be determined using an arbitrary reference convention. 6 figs.
Phase front patterns in shape memory alloy strips
Lagoudas, D.C.; Howard, S.D. [Texas A& M Univ., TX (United States)
1995-12-31T23:59:59.000Z
Uniaxial thermomechanical tests of Shape Memory Alloy (SMA) Nitinol strips, below the austenitic start temperature, have shown the formation of multiple phase front patterns forming at approximately 45 degrees angle with respect to the applied load. These phase fronts, that separate self-accommodating martensitic variants from detwinned martensite, propagate along the specimen in the direction of applied load, until fully detwinned martensite is developed. Similar patterns of martensitic-austenitic phase fronts occur when the temperature is raised above austenitic finish, and uniaxial loading is applied to the strip specimens. An experimental study of this phenomenon, together with some preliminary modelling results will be presented. In contrast to the above uniform loading case, experimental results and numerical simulations for the propagation of a phase transformation front, induced by an imposed temperature gradient, will also be presented.
Entanglement, number fluctuations and optimized interferometric phase measurement
Q. Y. He; T. G. Vaughan; P. D. Drummond; M. D. Reid
2012-06-14T23:59:59.000Z
We derive a phase-entanglement criterion for two bosonic modes which is immune to number fluc- tuations, using the generalized Moore-Penrose inverse to normalize the phase-quadrature operator. We also obtain a phase-squeezing criterion that is immune to number fluctuations using similar techniques. These are utilized to obtain an operational definition of relative phase-measurement sensitivity, via analysis of phase measurement in interferometry. We show that these measures are proportional to enhanced phase-measurement sensitivity. The phase-entanglement criterion is a hallmark for a new type of quantum squeezing, namely planar quantum squeezing. This has the property that it squeezes two orthogonal spin directions simultaneously, which is possible owing to the fact that the SU(2) group that describes spin symmetry has a three-dimensional parameter space, of higher dimension than the group for photonic quadratures. The practical advantage of planar quantum squeezing is that, unlike conventional spin-squeezing, it allows noise reduction over all phase-angles simultaneously. The application of this type of squeezing is to quantum measure- ment of an unknown phase. We show that a completely unknown phase requires two orthogonal measurements, and that with planar quantum squeezing it is possible to reduce the measurement uncertainty independently of the unknown phase value. This is a different type of squeezing to the usual spin-squeezing interferometric criterion, which is only applicable when the measured phase is already known to a good approximation, or can be measured iteratively. As an example, we calcu- late the phase-entanglement of the ground state of a two-well, coupled Bose-Einstein condensate, similar to recent experiments. This system demonstrates planar squeezing in both the attractive and repulsive interaction regimes.
Phase Behavior in Asymmetric Polymer Blends
Nedoma, Alisyn Jenise
2010-01-01T23:59:59.000Z
Methods of X-ray and Neutron Scattering in Polymer Science;using small angle neutron scattering, was three times moreas small angle neutron scattering (SANS), directly measure
On the use of the theory of dynamical systems for transient problems
Ugo Galvanetto; Luca Magri
2014-11-01T23:59:59.000Z
This paper is a preliminary work to address the problem of dynamical systems with parameters varying in time. An idea to predict their behaviour is proposed. These systems are called \\emph{transient systems}, and are distinguished from \\emph{steady systems}, in which parameters are constant. In particular, in steady systems the excitation is either constant (e.g. nought) or periodic with amplitude, frequency and phase angle which do not vary in time. We apply our method to systems which are subjected to a transient excitation, which is neither constant nor periodic. The effect of switching-off and full-transient forces is investigated. The former can be representative of switching-off procedures in machines; the latter can represent earthquake vibrations, wind gusts, etc. acting on a mechanical system. This class of transient systems can be seen as the evolution of an ordinary steady system into another ordinary steady system, for both of which the classical theory of dynamical systems holds. The evolution from a steady system to the other is driven by a transient force, which is regarded as a map between the two steady systems.
The Price of Synchrony: Resistive Losses due to Phase Synchronization in Power Networks
Bassam Bamieh; Dennice F. Gayme
2012-09-21T23:59:59.000Z
We investigate the total resistive losses incurred in returning a power network of identical generators to a synchronous state following a transient stability event or in maintaining this state in the presence of persistent stochastic disturbances. We formulate this cost as the input-output $H^2$ norm of a linear dynamical system with distributed disturbances. We derive an expression for the total resistive losses that scales with the size of the network as well as properties of the generators and power lines, but is independent of the network topology. This topologically invariant scaling of what we term the price of synchrony is in contrast to typical power system stability notions like rate of convergence or the region of attraction for rotor-angle stability. Our result indicates that highly connected power networks, whilst desirable for higher phase synchrony, do not offer an advantage in terms of the total resistive power losses needed to achieve this synchrony. Furthermore, if power flow is the mechanism used to achieve synchrony in highly-distributed-generation networks, the cost increases unboundedly with the number of generators.
Kim, Junghan; Iype, Eldhose; Frijns, Arjan J.H.; Nedea, Silvia V.; Steenhoven, Anton A. van
2014-07-01T23:59:59.000Z
Molecular dynamics simulations of heat transfer in gases are computationally expensive when the wall molecules are explicitly modeled. To save computational time, an implicit boundary function is often used. Steele's potential has been used in studies of fluid–solid interface for a long time. In this work, the conceptual idea of Steele's potential was extended in order to simulate water–silicon and water–silica interfaces. A new wall potential model is developed by using the electronegativity-equalization method (EEM), a ReaxFF empirical force field and a non-reactive molecular dynamics package PumMa. Contact angle simulations were performed in order to validate the wall potential model. Contact angle simulations with the resulting tabulated wall potentials gave a silicon–water contact angle of 129°, a quartz–water contact angle of 0°, and a cristobalite–water contact angle of 40°, which are in reasonable agreement with experimental values.
Yoji Kawamura; Hiroya Nakao; Kensuke Arai; Hiroshi Kori; Yoshiki Kuramoto
2008-07-08T23:59:59.000Z
The collective phase response to a macroscopic external perturbation of a population of interacting nonlinear elements exhibiting collective oscillations is formulated for the case of globally-coupled oscillators. The macroscopic phase sensitivity is derived from the microscopic phase sensitivity of the constituent oscillators by a two-step phase reduction. We apply this result to quantify the stability of the macroscopic common-noise induced synchronization of two uncoupled populations of oscillators undergoing coherent collective oscillations.
Phase synchronization of instrumental music signals
Sayan Mukherjee; Sanjay Kumar Palit; Santo Banerjee; MRK Ariffin; D. K. Bhattacharya
2014-09-04T23:59:59.000Z
Signal analysis is one of the finest scientific techniques in communication theory. Some quantitative and qualitative measures describe the pattern of a music signal, vary from one to another. Same musical recital, when played by different instrumentalists, generates different types of music patterns. The reason behind various patterns is the psychoacoustic measures - Dynamics, Timber, Tonality and Rhythm, varies in each time. However, the psycho-acoustic study of the music signals does not reveal any idea about the similarity between the signals. For such cases, study of synchronization of long-term nonlinear dynamics may provide effective results. In this context, phase synchronization (PS) is one of the measures to show synchronization between two non-identical signals. In fact, it is very critical to investigate any other kind of synchronization for experimental condition, because those are completely non identical signals. Also, there exists equivalence between the phases and the distances of the diagonal line in Recurrence plot (RP) of the signals, which is quantifiable by the recurrence quantification measure tau-recurrence rate. This paper considers two nonlinear music signals based on same raga played by two eminent sitar instrumentalists as two non-identical sources. The psycho-acoustic study shows how the Dynamics, Timber, Tonality and Rhythm vary for the two music signals. Then, long term analysis in the form of phase space reconstruction is performed, which reveals the chaotic phase spaces for both the signals. From the RP of both the phase spaces, tau-recurrence rate is calculated. Finally by the correlation of normalized tau-recurrence rate of their 3D phase spaces and the PS of the two music signals has been established. The numerical results well support the analysis.
Ni coarsening in the three-phase solid oxide fuel cell anode - a phase-field simulation study
Chen, Hsun-Yi; Cronin, J Scott; Wilson, James R; Barnett, Scott A; Thornton, Katsuyo
2012-01-01T23:59:59.000Z
Ni coarsening in Ni-yttria stabilized zirconia (YSZ) solid oxide fuel cell anodes is considered a major reason for anode degradation. We present a predictive, quantative modeling framework based on the phase-field approach to systematically examine coarsening kinetics in such anodes. The initial structures for simulations are experimentally acquired functional layers of anodes. Sample size effects and error analysis of contact angles are examined. Three phase boundary (TPB) lengths and Ni surface areas are quantatively identified on the basis of the active, dead-end, and isolated phase clusters throughout coarsening. Tortuosity evolution of the pores is also investigated. We find that phase clusters with larger characteristic length evolve slower than those with smaller length scales. As a result, coarsening has small positive effects on transport, and impacts less on the active Ni surface area than the total counter part. TPBs, however, are found to be sensitive to local morphological features and are only i...
Gallegos-Lopez, Gabriel
2012-10-02T23:59:59.000Z
Methods, system and apparatus are provided for increasing voltage utilization in a five-phase vector controlled machine drive system that employs third harmonic current injection to increase torque and power output by a five-phase machine. To do so, a fundamental current angle of a fundamental current vector is optimized for each particular torque-speed of operating point of the five-phase machine.
Numerical Results for the Blue Phases
G. P. Alexander; J. M. Yeomans
2009-06-04T23:59:59.000Z
We review recent numerical work investigating the equilibrium phase diagram, and the dynamics, of the cholesteric blue phases. In equilibrium numerical results confirm the predictions of the classic analytical theories, and extend them to incorporate different values of the elastic constants, or the effects of an applied electric field. There is a striking increase in the stability of blue phase I in systems where the cholesteric undergoes helical sense inversion, and the anomalous electrostriction observed in this phase is reproduced. Solving the equations of motion allows us to present results for the phase transition kinetics of blue phase I under dielectric or flexoelectric coupling to an applied electric field. We also present simulations of the blue phases in a flow field, showing how the disclination network acts to oppose the flow. The results are based on the Landau-de Gennes exapnsion of the liquid crystal free energy: that such a simple and elegant theory can predict such complex and subtle physical behaviour is remarkable.
Nuclear dynamics induced by antiprotons
Zhao-Qing Feng
2015-05-20T23:59:59.000Z
Reaction dynamics in collisions of antiprotons on nuclei is investigated within the Lanzhou quantum molecular dynamics model. The reaction channels of elastic scattering, annihilation, charge exchange and inelastic collisions of antiprotons on nucleons have been included in the model. Dynamics on particle production, in particular pions, kaons, antikaons and hyperons, is investigated in collisions of $\\overline{p}$ on $^{12}$C, $^{20}$Ne, $^{40}$Ca and $^{181}$Ta from a low to high incident momenta. It is found that the annihilations of $\\overline{p}$ on nucleons are of importance on the dynamics of particle production in phase space. Hyperons are mainly produced via meson induced reactions on nucleons and strangeness exchange collisions, which lead to the delayed emission in antiproton-nucleus collisions.
Water Dynamics at Rough Interfaces
Markus Rosenstihl; Kerstin Kämpf; Felix Klameth; Matthias Sattig; Michael Vogel
2014-07-21T23:59:59.000Z
We use molecular dynamics computer simulations and nuclear magnetic resonance experiments to investigate the dynamics of water at interfaces of molecular roughness and low mobility. We find that, when approaching such interfaces, the structural relaxation of water, i.e., the $\\alpha$ process, slows down even when specific attractive interactions are absent. This prominent effect is accompanied by a smooth transition from Vogel to Arrhenius temperature dependence and by a growing importance of jump events. Consistently, at protein surfaces, deviations from Arrhenius behavior are weak when free water does not exist. Furthermore, in nanoporous silica, a dynamic crossover of liquid water occurs when a fraction of solid water forms near 225 K and, hence, the liquid dynamics changes from bulk-like to interface-dominated. At sufficiently low temperatures, water exhibits a quasi-universal $\\beta$ process, which is characterized by an activation energy of $E_a\\!=\\!0.5$ eV and involves anisotropic reorientation about large angles. As a consequence of its large amplitude, the faster $\\beta$ process destroys essentially all orientational correlation, rendering observation of a possible slower $\\alpha$ process difficult in standard experiments. Nevertheless, we find indications for the existence of structural relaxation down to a glass transition of interfacial water near 185 K. Hydrated proteins show a highly restricted backbone motion with an amplitude, which decreases upon cooling and vanishes at comparable temperatures, providing evidence for a high relevance of water rearrangements in the hydration shell for secondary protein relaxations.
Measuring the Running of the Electromagnetic Coupling Alpha in Small Angle Bhabha Scattering
Luca Trentadue
2006-08-07T23:59:59.000Z
We propose a method to determine the running of $\\alpha_{QED}$ from the measurement of small-angle Bhabha scattering. The method is suited to high statistics experiments at $e^{+} e^{-}$ colliders, which are equipped with luminometers in the appropriate angular region. We present a new simulation code predicting small-angle Bhabha scattering. A detailed description of this idea can be found in A.B. Arbuzov, D. Haidt, C. Matteuzzi, M. Paganoni and L. Trentadue, The running of the electromagnetic coupling alpha in small-angle Bhabha scattering, Eur. Phys. J. C34, 267 (2004).
Phase Synchronization between Two Superradiant Lasers
Joshua M. Weiner; Kevin C. Cox; Justin G. Bohnet; James K. Thompson
2015-03-22T23:59:59.000Z
We experimentally demonstrate synchronization between two distinct ensembles of cold atoms undergoing steady state superradiance within a single longitudinal and transverse mode of the same optical cavity. The synchronization process is studied first in terms of the time dynamics of re-synchronization when the phase alignment of the two oscillators is abruptly broken. We also observe the steady state behavior of the lasers as their relative frequency is continuously varied. This system has the potential to realize a non-equilibrium quantum phase transition and could inform future implementations of milliHertz linewidth lasers.
Liu, Jian; Miller, William H.
2008-01-01T23:59:59.000Z
in a single phase space integral—beyond the linearizedreplace the phase space integral in Eq. (2.1) by a timeclassical dynamics of the path integral beads of the quantum
Mahabir, Suanne [University of Western Ontario, The; Small, Darcy [University of Western Ontario, The; Li, Ming [University of Connecticut, Storrs; Wan, Wankei [University of Western Ontario, The; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Littrell, Ken [ORNL; Katsaras, John [ORNL; Nieh, Mu-Ping [University of Connecticut, Storrs
2013-01-01T23:59:59.000Z
Mixtures of dimyristoyl-phosphatidylcholine (DMPC), dimyristoyl-phosphatidylglycerol (DMPG) and dihexanoylphosphatidylcholine (DHPC) in aqueous solutions spontaneously form monodisperse, bilayered nanodiscs (also known as bicelles ) at or below the melting transition temperature of DMPC (TM ~23 C). In dilute systems above the main transition temperature TM of DMPC, bicelles coalesce (increasing their diameter) and eventually self-fold into unilamellar vesicles (ULVs). Time resolved small angle neutron scattering was used to study the growth kinetics of nanodiscs below and equal to TM over a period of hours as a function of temperature at two lipid concentrations in presence or absence of NaCl salt. Bicelles seem to undergo a sudden initial growth phase with increased temperature, which is then followed by a slower reaction-limited growth phase that depends on ionic strength, lipid concentration and temperature. The bicelle interaction energy was derived from the colloidal theory of Derjaguin and Landau, and Verwey and Overbeek (DLVO). While the calculated total energy between discs is attractive and proportional to their growth rate, a more detailed mechanism is proposed to describe the mechanism of disc coalescence. After annealing at low temperature (low-T), samples were heated to 50 C in order to promote the formation of ULVs. Although the low-T annealing of samples has only a marginal effect on the mean size of end-state ULVs, it does affect their polydispersity, which increases with increased T, presumably driven by the entropy of the system.
ANGLE-RESOLVED PHOTOEMISSION STUDIES OF Ag, Au, AND Pt
Davis, R.F.; Mills, K.A.; Thornton, G.; Kevan, S.D.; Shirley, D.A.
1980-06-01T23:59:59.000Z
An important question regarding the technique of angle-resolved photoemission (ARP) is the extent to which it can be used to determine experimental valence-band dispersion relations E{sub i}({rvec k}) for single crystalline solids. In the case of the 3d and 4d transition metals, studies of copper, nickel, palladium, and silver, show that a model based on the assumption of direct interband transitions (direct-transition model) may be used, in conjunction with an appropriate final-state dispersion relation E{sub f}({rvec k}), to elucidate E{sub i}({rvec k}) for these materials along several high symmetry lines (primarily {Gamma}{Lambda}L) in k-space. To answer this question more generally, we have undertaken an extensive study of the valence band structures of other transition metals along various k-space lines. To date, studies have been extended to the (111) faces of the 5d metals Pt and Au along with the Pt(100) ((5 x 20) surface structure) face, and the (110) and (100) faces of Ag. The experiments were all conducted at SSRL, using synchrotron radiation in the range 6 eV < h{nu} < 34 eV. The results of these studies, combined with our previous Ag(111) work at these energies, allow us to invoke important conclusions concerning the relationships between ARP data, E{sub i}({rvec k}) and E{sub f}({rvec k}) for these materials. Several are summarized. For each crystal face investigated, the direct-transition model, along with a simple quasi-free-electron E{sub f}({rvec k}), was sufficient to determine experimental E{sub i}({rvec k}) relations along the appropriate k-space line that were in general agreement with theoretical RAPW band structure calculations. Essentially, we required E{sub f}({rvec k}) to be of the form (h{sup 2}/2m*)|{rvec k} + {rvec G}|{sup 2} + V{sub o}, where {rvec G} is a reciprocal lattice vector, fitting this relation to the appropriate calculated bulk conduction band near the center of the line under investigation, with the inner potential V{sub o} and the reduced mass m* as free parameters. An additional shift of V{sub o} was necessary for Ag(110) and Pt(100) data, to obtain better agreement with theoretical bands. While generally excellent agreement between experimental and theoretical bands was found for Ag, as was the case for other 3d and 4d metals, substantial disagreement was observed for Pt and Au in parts of the Brillouin zone. This is probably an indication that further theoretical work is needed for these more complicated elements. The agreement in Ag is illustrated by Fig. 1, where experimental and theoretical bands are compared for all three high-symmetry directions. The determinations of E{sub i}({rvec k}) for the {Lambda} directions were relatively simple because peaks in the ARP spectra of (111) faces were essentially all attributable to primary direct transition. However, the {Sigma}, {Sigma}{prime}, and {Delta} directions were complicated by secondary emission peaks and dispersionless density-of-states (DOS) features in the spectra of the (100) and (110) faces. Peak intensity resonances associated with the bulk conduction band structure near {Lambda} were observed for each crystal face, and these simplified the assignment of peaks in the ARP spectra. The relationship between these resonances, which appear to be rather general phenomena, and E{sub f}({rvec k}), will be discussed. In summary, it is clear from these and other studies that the ARP technique, in conjunction with the direct-transition model, is generally applicable to valence band mapping in single crystals, provided that a suitable final-state dispersion relation can be calculated. However, complications like those observed in the ARP spectra of Ag, Pt, and Au may make the determination of E{sub i}({rvec k}) relations considerably more difficult for more complicated systems.
Static and dynamic properties of a reversible gel
Pablo I. Hurtado; Pinaki Chaudhuri; Ludovic Berthier; Walter Kob
2008-11-10T23:59:59.000Z
We study a microscopically realistic model of a physical gel and use computer simulations to investigate its static and dynamic properties at thermal equilibrium. The phase diagram comprises a sol phase, a coexistence region ending at a critical point, a gelation line, and an equilibrium gel phase unrelated to phase separation. The global structure of the gel is homogeneous, but the stress is supported by a fractal network. Gelation results in a dramatic slowing down of the dynamics, which can be used to locate the transition, which otherwise shows no structural signatures. Moreover, the equilibrium gel dynamics is highly heterogeneous as a result of the presence of particle families with different mobilities. An analysis of gel dynamics in terms of mobile and arrested particles allows us to elucidate several differences between the dynamics of equilibrium gels and that of glass-formers.
The effects of diamond injector angles on flow structures at various Mach numbers
McLellan, Justin Walter
2006-10-30T23:59:59.000Z
Numerical simulations of a three dimensional diamond jet interaction flowfield at various diamond injector half angles into a supersonic crossflow were presented in this thesis. The numerical study was performed to improve the understanding...
McGuire, Molly E
2005-01-01T23:59:59.000Z
An operational algorithm for blind angle control is developed to optimize the daylighting performance of a system of reflective Venetian blinds. Numerical modeling and experiment confirm that independent control of alternating ...
Using Semantic Similarity to Predict Angle and Distance of Objects in Images
Davies, Jim
sterling@sterlingsomers .com Jonathan GagnÃ© Dept. Systems Design Engineering University of Waterloo 200Using Semantic Similarity to Predict Angle and Distance of Objects in Images Sterling Somers
Liu, Dazhi
Small-angle neutron scattering (SANS) is the most significant neutron technique in terms of impact on science and engineering. However, the basic design of SANS facilities has not changed since the technique’s inception ...
Joint anisotropy characterization and image formation in wide-angle synthetic aperture radar
Varshney, Kush R. (Kush Raj)
2006-01-01T23:59:59.000Z
Imagery formed from wide-angle synthetic aperture radar (SAR) measurements has fine cross-range resolution in principle. However, conventional SAR image formation techniques assume isotropic scattering, which is not valid ...
The effects of diamond injector angles on flow structures at various Mach numbers
McLellan, Justin Walter
2006-10-30T23:59:59.000Z
Numerical simulations of a three dimensional diamond jet interaction flowfield at various diamond injector half angles into a supersonic crossflow were presented in this thesis. The numerical study was performed to improve ...
Acoustic And Elastic Reverse-Time Migration: Novel Angle-Domain Imaging Conditions And Applications
Yan, Rui
2013-01-01T23:59:59.000Z
imaging. For small angles, the PPP and PPS paths carry mosttraveling paths are labeled with two legs such as PPP-PSP.The left leg (PPP) is the downgoing path and the right leg (
The effects of lithology and initial fault angle in physical models of fault-propagation folds
McLain, Christopher Thomas
2001-01-01T23:59:59.000Z
Experimentally deformed physical rock models are used to examine the effects of changing mechanical stratigraphy and initial fault angle on the development of fault-propagation folds over a flat-ramp-flat thrust geometry. This study also...
A Comprehensive Comparison Between Angles-Only Initial Orbit Determination Techniques
Schaeperkoetter, Andrew Vernon
2012-02-14T23:59:59.000Z
During the last two centuries many methods have been proposed to solve the angles-only initial orbit determination problem. As this problem continues to be relevant as an initial estimate is needed before high accuracy orbit determination...
Neutrino Oscillations With Recently Measured Sterile-Active Neutrino Mixing Angle
Kisslinger, Leonard S
2014-01-01T23:59:59.000Z
This brief report is an extension of a prediction of neutrino oscillation with a sterile neutrino using parameters of the sterile neutrino mass and mixing angle recently extracted from experiment.
Hirsch, Matthew Waggener
We propose a flexible light field camera architecture that is at the convergence of optics, sensor electronics, and applied mathematics. Through the co-design of a sensor that comprises tailored, Angle Sensitive Pixels and ...
GEOGRAPHY 104 BOUNDARY LAYER CLIMATES Assignment #4: Solar Radiation on Angled Surfaces
angle should the collector be adjusted for the solstices and equinox. Using the diagrams that you have below, calculate the rates of solar heating (SH) at solar noon on the equinox using the following
Improved measurements of the neutrino mixing angle ?[subscript 13] with the Double Chooz detector
Conrad, Janet
The Double Chooz experiment presents improved measurements of the neutrino mixing angle ?[subscript 13] using the data collected in 467.90 live days from a detector positioned at an average distance of 1050 m from two ...
Nodal Quasiparticle Meltdown in Ultra-High Resolution Pump-Probe Angle-Resolved Photoemission
Graf, Jeff; Jozwiak, Chris; Smallwood, Chris L.; Eisaki, H.; Kaindl, Robert A.; Lee, Dung-Hai; Lanzara, Alessandra
2011-06-03T23:59:59.000Z
High-T{sub c} cuprate superconductors are characterized by a strong momentum-dependent anisotropy between the low energy excitations along the Brillouin zone diagonal (nodal direction) and those along the Brillouin zone face (antinodal direction). Most obvious is the d-wave superconducting gap, with the largest magnitude found in the antinodal direction and no gap in the nodal direction. Additionally, while antin- odal quasiparticle excitations appear only below T{sub c}, superconductivity is thought to be indifferent to nodal excitations as they are regarded robust and insensitive to T{sub c}. Here we reveal an unexpected tie between nodal quasiparticles and superconductivity using high resolution time- and angle-resolved photoemission on optimally doped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}#14;. We observe a suppression of the nodal quasiparticle spectral weight following pump laser excitation and measure its recovery dynamics. This suppression is dramatically enhanced in the superconducting state. These results reduce the nodal-antinodal dichotomy and challenge the conventional view of nodal excitation neutrality in superconductivity. The electronic structures of high-Tc cuprates are strongly momentum-dependent. This is one reason why the momentum-resolved technique of angle-resolved photoemission spectroscopy (ARPES) has been a central tool in the #12;field of high-temperature superconductivity. For example, coherent low energy excitations with momenta near the Brillouin zone face, or antinodal quasiparticles (QPs), are only observed below T{sub c} and have been linked to superfluid density. They have therefore been the primary focus of ARPES studies. In contrast, nodal QPs, with momenta along the Brillouin zone diagonal, have received less attention and are usually regarded as largely immune to the superconducting transition because they seem insensitive to perturbations such as disorder, doping, isotope exchange, charge ordering, and temperature. Clearly, finding any strong dependencies of the nodal QPs will alter the conventional view and enrich our understanding of high temperature superconductivity. Time resolution through pump-and-probe techniques adds a new dimension to ARPES by directly measuring how the electronic structure of a material responds to perturbations on femtosecond time scales. Here we report a unique ultrafast time-resolved ARPES study of a high-T{sub c} cuprate superconductor. Compared to previous time-resolved studies, the primary advantage of this work is an unprecedented momentum (angular) resolution ({Delta}#1;k~ #24;0.003 vs. 0.05 {#23;Angstrom}{sup -1}), on par with that of state-of-the-art ARPES. This has allowed the time-resolved measurement of signi#12;cantly sharper QP spectral peaks with strikingly larger peak-to-background ratios than previously reported.16 Additionally, a lower pump fluence is used (<40{micro}#22;J/cm{sup 2} vs. #24;100#22;{micro}J/cm{sup 2}), which reduces pump-induced sample temperature increase and related thermal smearing of spectral features. This allows us to uncover a surprising meltdown of nodal QP spectral weight following pump laser excitation. This meltdown is only observed in the superconducting state and for QPs with binding energy less than the kink energy,19 revealing a link between nodal QPs and superconductivity.
An On-line Method for Stator Fault Detection in Multi-phase PMSM Drives
Paris-Sud XI, UniversitÃ© de
An On-line Method for Stator Fault Detection in Multi-phase PMSM Drives Fabien Meinguet*, Eric deals with an on-line fault detection method for multi-phase PMSM drives. The method is based to obtain good dynamic properties. Thus, the drive will be composed of a multi-phase machine, a multi
The effect of fuel injection angle and pressure on combustor performance
Brown, Michael Lee
1976-01-01T23:59:59.000Z
)ed in the areas of combustion and fuels. Michael is a member of the American Society of Mechanical Engineers, the Society of Automotive Engineers, and Pi Tau Sigma. Mr. Brown's permanent address is: P. O. Box 495 Duluth, Georgia 30136 The typist.... Furthermore, FAR can effect combustor performance. Two different mass flows, 2. 9 and 14. 7 pounds per hour, yielding two different FARs were run at each injection angle and pressure. Concerning fuel injection parameters, six different injection angles (0...
Mike L. Laue
1997-05-08T23:59:59.000Z
This project attempts to demonstrate the effectiveness of exploiting thin-layered, low-energy deposits at the distal margin of a propagating turbidite complex through the use of hydraulically-fractured horizontal or high-angle wells. The combination of a horizontal or high-angled well and hydraulic fracturing will allow greater pay exposure than can be achieved with conventional vertical wells while maintaining vertical communication between thininterbedded layers and the well bore.
Laveissière, G; Jaminion, S; Jutier, C; Todor, L; 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; Kamalov, S; 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 K; 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; 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; Papandreou, Z; 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; Tiator, L; Tieulent, R; Tomasi-Gustafsson, E; Tsubota, H; Ueno, H; Ulmer, P E; Urciuoli, G M; Van De Vyver, R; Van, R L J; der Meer; 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
2004-01-01T23:59:59.000Z
Photon electroproduction from hydrogen at backward angles and momentum transfer squared of $Q^{2}=1.0Gev^{2}$
Real-Time Magnetic Field Pitch Angle Estimation with a Motional Stark Effect Diagnostic Using Kalman Filtering
Evaluation of the Faraday Angle by Numerical Methods and Comparison with the Tore Supra and JET Polarimeter Electronics
Associative memory in phasing neuron networks
Nair, Niketh S [ORNL; Bochove, Erik J. [United States Air Force Research Laboratory, Kirtland Air Force Base; Braiman, Yehuda [ORNL
2014-01-01T23:59:59.000Z
We studied pattern formation in a network of coupled Hindmarsh-Rose model neurons and introduced a new model for associative memory retrieval using networks of Kuramoto oscillators. Hindmarsh-Rose Neural Networks can exhibit a rich set of collective dynamics that can be controlled by their connectivity. Specifically, we showed an instance of Hebb's rule where spiking was correlated with network topology. Based on this, we presented a simple model of associative memory in coupled phase oscillators.
Accelerator dynamics and beam aperture
Parsa, Z.
1986-10-01T23:59:59.000Z
We present an analytical method for analyzing accelerator dynamics, including higher order effects of multipoles on the beam. This formalism provides a faster alternative to particle tracking. Simplectic expressions for the emittance and phase describing the dynamical behavior of a particle in a circular accelerator are derived using second order perturbation theory (in the presence of nonlinear elements, e.g., sextupoles, octupoles). These expressions are successfully used to calculate the emittance growth, smear and linear aperture. Our findings compare well with results obtained from tracking programs. In addition perturbation to betatron tune; resonance strengths; stop bandwidth; fixed points; island width; and Chirikov criteria are calculated.
Theoretical studies of combustion dynamics
Bowman, J.M. [Emory Univ., Atlanta, GA (United States)
1993-12-01T23:59:59.000Z
The basic objectives of this research program are to develop and apply theoretical techniques to fundamental dynamical processes of importance in gas-phase combustion. There are two major areas currently supported by this grant. One is reactive scattering of diatom-diatom systems, and the other is the dynamics of complex formation and decay based on L{sup 2} methods. In all of these studies, the authors focus on systems that are of interest experimentally, and for which potential energy surfaces based, at least in part, on ab initio calculations are available.
Zeghib, Abdelghani
Introduction Results Linear Dynamics Lorentz Dynamics Actions of discrete groups on stationary Piccione) Geodeycos Meeting, Lyon, 28-30 April 2010 Abdelghani Zeghib Dynamics on Lorentz manifolds #12;Introduction Results Linear Dynamics Lorentz Dynamics Motivations and questions Examples 1 Introduction
Measuring contact angle and meniscus shape with a reflected laser beam
Eibach, T. F.; Nguyen, H.; Butt, H. J.; Auernhammer, G. K., E-mail: auhammer@mpip-mainz.mpg.de [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Fell, D. [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany) [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Center of Smart Interfaces, Technical University Darmstadt, 64287 Darmstadt (Germany)
2014-01-15T23:59:59.000Z
Side-view imaging of the contact angle between an extended planar solid surface and a liquid is problematic. Even when aligning the view perfectly parallel to the contact line, focusing one point of the contact line is not possible. We describe a new measurement technique for determining contact angles with the reflection of a widened laser sheet on a moving contact line. We verified this new technique measuring the contact angle on a cylinder, rotating partially immersed in a liquid. A laser sheet is inclined under an angle ? to the unperturbed liquid surface and is reflected off the meniscus. Collected on a screen, the reflection image contains information to determine the contact angle. When dividing the laser sheet into an array of laser rays by placing a mesh into the beam path, the shape of the meniscus can be reconstructed from the reflection image. We verified the method by measuring the receding contact angle versus speed for aqueous cetyltrimethyl ammonium bromide solutions on a smooth hydrophobized as well as on a rough polystyrene surface.
Shape Dynamics in 2+1 Dimensions
Timothy Budd; Tim Koslowski
2011-07-07T23:59:59.000Z
Shape Dynamics is a formulation of General Relativity where refoliation invariance is traded for local spatial conformal invariance. In this paper we explicitly construct Shape Dynamics for a torus universe in 2+1 dimensions through a linking gauge theory that ensures dynamical equivalence with General Relativity. The Hamiltonian we obtain is formally a reduced phase space Hamiltonian. The construction of the Shape Dynamics Hamiltonian on higher genus surfaces is not explicitly possible, but we give an explicit expansion of the Shape Dynamics Hamiltonian for large CMC volume. The fact that all local constraints are linear in momenta allows us to quantize these explicitly, and the quantization problem for Shape Dynamics turns out to be equivalent to reduced phase space quantization. We consider the large CMC-volume asymptotics of conformal transformations of the wave function. We then use the similarity of Shape Dynamics on the 2-torus with the explicitly constructible strong gravity (BKL) Shape Dynamics Hamiltonian in higher dimensions to suggest a quantization strategy for Shape Dynamics.
Boyer, Edmond
of small angle neutron scattering from fluids in a constant shear gradient. Typical systems which can angle neutron scattering experiments with liquids have given information about structural pro- perties759 Apparatus for the investigation of liquid systems in a shear gradient by small angle neutron
Rubloff, Gary W.
Small angle neutron scattering study of deuterated sodium dodecylsulfate micellization in dilute 2010 Keywords: Poly((2edimethylamino)ethyl methacrylate) Micelle Small angle neutron scattering a b angle neutron scattering. We found three transitions of the poly ((2edimethylamino)ethyl methacrylate
Deep optical penetration dynamics in photo-bending
Daniel Corbett; Chen Xuan; Mark Warner
2015-07-07T23:59:59.000Z
We model both the photo-stationary state and dynamics of an illuminated, photo-sensitive, glassy liquid crystalline sheet. To illustrate the interplay between local tilt $\\theta$ of the sheet, effective incident intensity, curvature and dynamics, we adopt the simplest variation of local incident light intensity with angle, that is $\\cos\\theta$. The tilt in the stationary state never overshoots the vertical, but maximum curvature could be seen in the middle of the sheet for intense light. In dynamics, overshoot and self-eclipsing arise, revealing how important moving fronts of light penetration are. Eclipsing is qualitatively as in the experiments of Ikeda and Yu (2003).
G. P. Alexander; J. M. Yeomans
2006-09-22T23:59:59.000Z
We present an investigation of the phase diagram of cholesteric liquid crystals within the framework of Landau - de Gennes theory. The free energy is modified to incorporate all three Frank elastic constants and to allow for a temperature dependent pitch in the cholesteric phase. It is found that the region of stability of the cubic blue phases depends significantly on the value of the elastic constants, being reduced when the bend elastic constant is larger than splay and when twist is smaller than the other two. Most dramatically we find a large increase in the region of stability of blue phase I, and a qualitative change in the phase diagram, in a system where the cholesteric phase displays helix inversion.
Michael, Joseph R. (Albuquerque, NM); Goehner, Raymond P. (Albuquerque, NM); Schlienger, Max E. (Albuquerque, NM)
2001-01-01T23:59:59.000Z
A method and apparatus for determining the crystalline phase and crystalline characteristics of a sample. This invention provides a method and apparatus for unambiguously identifying and determining the crystalline phase and crystalline characteristics of a sample by using an electron beam generator, such as a scanning electron microscope, to obtain a backscattered electron Kikuchi pattern of a sample, and extracting crystallographic and composition data that is matched to database information to provide a quick and automatic method to identify crystalline phases.
G P Alexander; J M Yeomans
2007-07-01T23:59:59.000Z
We describe the occurence and properties of liquid crystal phases showing two dimensional splay and bend distortions which are stabilised by flexoelectric interactions. These phases are characterised by regions of locally double splayed order separated by topological defects and are thus highly analogous to the blue phases of cholesteric liquid crystals. We present a mean field analysis based upon the Landau--de Gennes Q-tensor theory and construct a phase diagram for flexoelectric structures using analytic and numerical results. We stress the similarities and discrepancies between the cholesteric and flexoelectric cases.
Thermodynamically Stable Blue Phases
F. Castles; S. M. Morris; E. M. Terentjev; H. J. Coles
2011-01-28T23:59:59.000Z
We show theoretically that flexoelectricity stabilizes blue phases in chiral liquid crystals. Induced internal polarization reduces the elastic energy cost of splay and bend deformations surrounding singular lines in the director field. The energy of regions of double twist is unchanged. This in turn reduces the free energy of the blue phase with respect to that of the chiral nematic phase, leading to stability over a wider temperature range. The theory explains the discovery of large temperature range blue phases in highly flexoelectric "bimesogenic" and "bent-core" materials, and predicts how this range may be increased further.
Long Time Evolution of Phase Oscillator Systems
Edward Ott; Thomas M. Antonsen
2009-04-16T23:59:59.000Z
It is shown, under weak conditions, that the dynamical evolution of an important class of large systems of globally coupled, heterogeneous frequency, phase oscillators is, in an appropriate physical sense, time-asymptotically attracted toward a reduced manifold of system states. This manifold, which is invariant under the system evolution, was previously known and used to facilitate the discovery of attractors and bifurcations of such systems. The result of this paper establishes that attractors for the order parameter dynamics obtained by restriction to this reduced manifold are, in fact, the only such attractors of the full system. Thus all long time dynamical behavior of the order parameters of these systems can be obtained by restriction to the reduced manifold.
Emery, V.J. [Brookhaven National Lab., Upton, NY (United States); Kivelson, S.A. [California Univ., Los Angeles, CA (United States). Dept. of Physics
1993-12-31T23:59:59.000Z
In the past few years there has been a resurgence of interest in dynamical impurity problems, as a result of developments in the theory of correlated electron systems. The general dynamical impurity problem is a set of conduction electrons interacting with an impurity which has internal degrees of freedom. The simplest and earliest example, the Kondo problem, has attracted interest since the mid-sixties not only because of its physical importance but also as an example of a model displaying logarithmic divergences order by order in perturbation theory. It provided one of the earliest applications of the renormalization group method, which is designed to deal with just such a situation. As we shall see, the antiferromagnetic Kondo model is controlled by a strong-coupling fixed point, and the essence of the renormalization group solution is to carry out the global renormalization numerically starting from the original (weak-coupling) Hamiltonian. In these lectures, we shall describe an alternative route in which we identify an exactly solvable model which renormalizes to the same fixed point as the original dynamical impurity problem. This approach is akin to determining the critical behavior at a second order phase transition point by solving any model in a given universality class.
Anomalous small angle x-ray scattering studies of amorphous metal-germanium alloys
Rice, M.
1993-12-01T23:59:59.000Z
This dissertation addresses the issue of composition modulation in sputtered amorphous metal-germanium thin films with the aim of understanding the intermediate range structure of these films as a function of composition. The investigative tool used in this work is anomalous small-angle X-ray scattering (ASAXS). The primary focus of this investigation is the amorphous iron-germanium (a-Fe{sub x}Ge{sub 100-x}) system with particular emphasis on the semiconductor-rich regime. Brief excursions are made into the amorphous tungsten-germanium (a-W{sub x}Ge{sub 100-x}) and the amorphous molybdenum-germanium (a-Mo{sub x}Ge{sub 100-x}) systems. All three systems exhibit an amorphous structure over a broad composition range extending from pure amorphous germanium to approximately 70 atomic percent metal when prepared as sputtered films. Across this composition range the structures change from the open, covalently bonded, tetrahedral network of pure a-Ge to densely packed metals. The structural changes are accompanied by a semiconductor-metal transition in all three systems as well as a ferromagnetic transition in the a-Fe{sub x}Ge{sub 100-x} system and a superconducting transition in the a-Mo{sub x}Ge{sub 100-x} system. A long standing question, particularly in the a-Fe{sub x}Ge{sub 100-x} and the a-Mo{sub x}Ge{sub 100-x} systems, has been whether the structural changes (and therefore the accompanying electrical and magnetic transitions) are accomplished by homogeneous alloy formation or phase separation. The application of ASAXS to this problem proves unambiguously that fine scale composition modulations, as distinct from the simple density fluctuations that arise from cracks and voids, are present in the a-Fe{sub x}Ge{sub 100-x}, a-W{sub x}Ge{sub 100-x}, and a-Mo{sub x}Ge{sub 100-x} systems in the semiconductor-metal transition region. Furthermore, ASAXS shows that germanium is distributed uniformly throughout each sample in the x<25 regime of all three systems.
Predissociation dynamics of lithium iodide
Schmidt, H; Stienkemeier, F; Bogomolov, A S; Baklanov, A V; Reich, D M; Skomorowski, W; Koch, C P; Mudrich, M
2015-01-01T23:59:59.000Z
The predissociation dynamics of lithium iodide (LiI) in the first excited A-state is investigated for molecules in the gas phase and embedded in helium nanodroplets, using femtosecond pump-probe photoionization spectroscopy. In the gas phase, the transient Li+ and LiI+ ion signals feature damped oscillations due to the excitation and decay of a vibrational wave packet. Based on high-level ab initio calculations of the electronic structure of LiI and simulations of the wave packet dynamics, the exponential signal decay is found to result from predissociation predominantly at the lowest avoided X-A potential curve crossing, for which we infer a coupling constant V=650(20) reciprocal cm. The lack of a pump-probe delay dependence for the case of LiI embedded in helium nanodroplets indicates fast droplet-induced relaxation of the vibrational excitation.
Dynamical Topological Order Parameters far from Equilibrium
Jan Carl Budich; Markus Heyl
2015-09-21T23:59:59.000Z
We report the discovery of a novel topological quantum number, represented by a momentum space winding number of the Pancharatnam geometric phase, that is dynamically defined and can change its integer value at discrete times where so called dynamical quantum phase transitions (DQPTs) occur. By contrast, straightforward non-equilibrium generalizations of conventional topological invariants are well known to be constants of motion under coherent time evolution. DQPTs have been recently introduced as a non-equilibrium analog in quantum real-time evolution of conventional phase transitions, where increasing time replaces the notion of conventional control parameters such as temperature. Here, studying quantum quenches in two-banded Bogoliubov de Gennes models, we identify for the first time a quantity that can be seen as the dynamical analog of an order parameter which changes its topologically quantized value at DQPTs.
Vocadlo, Lidunka
Phase transition in MgSiO3 perovskite in the earth's lower mantle Taku Tsuchiya*, Jun Tsuchiya April 2004; accepted 11 May 2004 Abstract A new polymorph of MgSiO3 more stable than the Pbnm-perovskite to those in which a phase transition in MgSiO3-perovskite has been observed by in situ angle dispersive X
Social Balance on Networks: The Dynamics of Friendship and Enmity
T. Antal; P. L. Krapivsky; S. Redner
2006-05-21T23:59:59.000Z
How do social networks evolve when both friendly and unfriendly relations exist? Here we propose a simple dynamics for social networks in which the sense of a relationship can change so as to eliminate imbalanced triads--relationship triangles that contains 1 or 3 unfriendly links. In this dynamics, a friendly link changes to unfriendly or vice versa in an imbalanced triad to make the triad balanced. Such networks undergo a dynamic phase transition from a steady state to "utopia"--all friendly links--as the amount of network friendliness is changed. Basic features of the long-time dynamics and the phase transition are discussed.
An Eight-Octant Phase-Mask Coronagraph
Murakami, N; Baba, N; Nishikawa, J; Tamura, M; Hashimoto, N; Abe, L
2008-01-01T23:59:59.000Z
We present numerical simulations and laboratory experiments on an eight-octant phase-mask (EOPM) coronagraph. The numerical simulations suggest that an achievable contrast for the EOPM coronagraph can be greatly improved as compared to that of a four-quadrant phase-mask (FQPM) coronagraph for a partially resolved star. On-sky transmission maps reveal that the EOPM coronagraph has relatively high optical throughput, a small inner working angle and large discovery space. We have manufactured an eight-segment phase mask utilizing a nematic liquid-crystal device, which can be easily switched between the FQPM and the EOPM modes. The laboratory experiments demonstrate that the EOPM coronagraph has a better tolerance of the tip-tilt error than the FQPM one. We also discuss feasibility of a fully achromatic and high-throughput EOPM coronagraph utilizing a polarization interferometric technique.
An Eight-Octant Phase-Mask Coronagraph
N. Murakami; R. Uemura; N. Baba; J. Nishikawa; M. Tamura; N. Hashimoto; L. Abe
2008-09-09T23:59:59.000Z
We present numerical simulations and laboratory experiments on an eight-octant phase-mask (EOPM) coronagraph. The numerical simulations suggest that an achievable contrast for the EOPM coronagraph can be greatly improved as compared to that of a four-quadrant phase-mask (FQPM) coronagraph for a partially resolved star. On-sky transmission maps reveal that the EOPM coronagraph has relatively high optical throughput, a small inner working angle and large discovery space. We have manufactured an eight-segment phase mask utilizing a nematic liquid-crystal device, which can be easily switched between the FQPM and the EOPM modes. The laboratory experiments demonstrate that the EOPM coronagraph has a better tolerance of the tip-tilt error than the FQPM one. We also discuss feasibility of a fully achromatic and high-throughput EOPM coronagraph utilizing a polarization interferometric technique.
NONE
1995-08-01T23:59:59.000Z
The Utility PhotoVoltaic Group (UPVG), supported by member dues and a grant from the US Department of Energy, has as its mission the acceleration of the use of cost-effective small-scale and emerging large-scale applications of photovoltaics for the benefit of electric utilities and their customers. Formed in October, 1992, with the support of the American Public Power Association, Edison Electric Institute, and the National Rural Electric Cooperative Association, the UPVG currently has 90 members from all sectors of the electric utility industry. The UPVG`s efforts as conceived were divided into four phases: Phase 0--program plan; Phase 1--organization and strategy development; Phase 2--creating market assurance; and Phase 3--higher volume purchases. The Phase 0 effort developed the program plan and was completed early in 1993. The Phase 1 goal was to develop the necessary background information and analysis to lead to a decision as to which strategies could be undertaken by utilities to promote greater understanding of PV markets and achieve increased volumes of PV purchases. This report provides the details of the UPVG`s Phase 2 efforts to initiate TEAM-UP, its multiyear, 50-MW hardware initiative.
Nugent, K.A.; Paganin, D.; Gureyev, T.E. (Melbourne)
2009-01-06T23:59:59.000Z
We are introduced to the effects of phase from the earliest days of our childhood, from the nursery rhyme above (or its less verbose for 'Twinkle, Twinkle Little Star') to the shimmer over a hot road and the network of bright lines at the bottom of a swimming pool. These are all manifestations of phase. And there are many more.
Dual-angle, self-calibrating Thomson scattering measurements in RFX-MOD
Giudicotti, L., E-mail: leonardo.giudicotti@unipd.it [Consorzio RFX, Corso Stati Uniti, 4, 35127 Padova (Italy); Department of Industrial Engineering, Padova University, Via Gradenigo 6/a, 35131 Padova (Italy); Pasqualotto, R. [Department of Industrial Engineering, Padova University, Via Gradenigo 6/a, 35131 Padova (Italy); Fassina, A. [Consorzio RFX, Corso Stati Uniti, 4, 35127 Padova (Italy)
2014-11-15T23:59:59.000Z
In the multipoint Thomson scattering (TS) system of the RFX-MOD experiment the signals from a few spatial positions can be observed simultaneously under two different scattering angles. In addition the detection system uses optical multiplexing by signal delays in fiber optic cables of different length so that the two sets of TS signals can be observed by the same polychromator. Owing to the dependence of the TS spectrum on the scattering angle, it was then possible to implement self-calibrating TS measurements in which the electron temperature T{sub e}, the electron density n{sub e} and the relative calibration coefficients of spectral channels sensitivity C{sub i} were simultaneously determined by a suitable analysis of the two sets of TS data collected at the two angles. The analysis has shown that, in spite of the small difference in the spectra obtained at the two angles, reliable values of the relative calibration coefficients can be determined by the analysis of good S/N dual?angle spectra recorded in a few tens of plasma shots. This analysis suggests that in RFX-MOD the calibration of the entire set of TS polychromators by means of the similar, dual-laser (Nd:YAG/Nd:YLF) TS technique, should be feasible.
Effect of the Collimator Angle on Dosimetric Verification of the Volumetric Modulated Arc Therapy
Kim, Yong Ho; Kim, Won Taek; Kim, Dong Won; Ki, Yongkan; Lee, Juhye; Bae, Jinsuk; Park, Dahl
2015-01-01T23:59:59.000Z
Collimator angle is usually rotated when planning volumetric modulated arc therapy (VMAT) due to the leakage of radiation between multi-leaf collimator (MLC) leaves. We studied the effect of the collimator angles on the results of dosimetric verification of the VMAT plans for head and neck patients. We studied VMAT plans for 10 head and neck patients. We made 2 sets of VMAT plans for each patient. Each set was composed of 10 plans with collimator angles of 0, 5, 10, 15, 20, 25, 30, 35, 40, 45 degrees. Plans in the first set were optimized individually and plans in the second set shared the 30 degree collimator angle optimization. Two sets of plans were verified using the 2-dimensional ion chamber array MatriXX (IBA Dosimetry, Germany). The comparison between the calculation and measurements were made by the $\\gamma$-index analysis. The $\\gamma$-index (2\\%/2 mm) and (3\\%/3 mm) passing rates had negative correlations with the collimator angle. Maximum difference between $\\gamma$-index (3\\%/3 mm) passing rates o...
The Artificial Sky Luminance And The Emission Angles Of The Upward Light Flux
P. Cinzano; F. J. Diaz Castro
1998-11-19T23:59:59.000Z
The direction of the upward light emission has different polluting effects on the sky depending on the distance of the observation site. We studied with detailed models for light pollution propagation the ratio $(b_{H})/(b_{L})$, at given distances from a city, between the artificial sky luminance $b_{H}$ produced by its upward light emission between a given threshold angle $\\theta_{0}$ and the vertical and the artificial sky luminance $b_{L}$ produced by its upward light emission between the horizontal and the threshold angle $\\theta_{0}$. Our results show that as the distance from the city increases the effects of the emission at high angles above the horizontal decrease relative to the effects of emission at lower angles above the horizontal. Outside some kilometers from cities or towns the light emitted between the horizontal and 10\\deg ~is as important as the light emitted at all the other angles in producing the artificial sky luminance. Therefore the protection of a site requires also a careful control of this emission which needs to be reduced to at most 1/10 of the remaining emission. The emission between the horizontal and 10\\deg ~is mostly produced by spill light from luminaires, so fully shielded fixtures (e.g. flat glass luminaires or asymmetric spot-lights installed without any tilt) are needed for this purpose.
Andreas, Loren B
2014-01-01T23:59:59.000Z
Determination of the 3D structure of membrane proteins is a frontier that is rapidly being explored due to the importance of membrane proteins in regulating cellular processes and because they are the target of many drugs. ...
Dynamical Friction on extended perturbers
O. Esquivel; B. Fuchs
2008-04-01T23:59:59.000Z
Following a wave-mechanical treatment we calculate the drag force exerted by an infinite homogeneous background of stars on a perturber as this makes its way through the system. We recover Chandrasekhar's classical dynamical friction (DF) law with a modified Coulomb logarithm. We take into account a range of models that encompasses all plausible density distributions for satellite galaxies by considering the DF exerted on a Plummer sphere and a perturber having a Hernquist profile. It is shown that the shape of the perturber affects only the exact form of the Coulomb logarithm. The latter converges on small scales, because encounters of the test and field stars with impact parameters less than the size of the massive perturber become inefficient. We confirm this way earlier results based on the impulse approximation of small angle scatterings.
Dynamical Friction on extended perturbers
Esquivel, O
2008-01-01T23:59:59.000Z
Following a wave-mechanical treatment we calculate the drag force exerted by an infinite homogeneous background of stars on a perturber as this makes its way through the system. We recover Chandrasekhar's classical dynamical friction (DF) law with a modified Coulomb logarithm. We take into account a range of models that encompasses all plausible density distributions for satellite galaxies by considering the DF exerted on a Plummer sphere and a perturber having a Hernquist profile. It is shown that the shape of the perturber affects only the exact form of the Coulomb logarithm. The latter converges on small scales, because encounters of the test and field stars with impact parameters less than the size of the massive perturber become inefficient. We confirm this way earlier results based on the impulse approximation of small angle scatterings.
Scalar $?^4$ field theory for active-particle phase separation
Raphael Wittkowski; Adriano Tiribocchi; Joakim Stenhammar; Rosalind J. Allen; Davide Marenduzzo; Michael E. Cates
2014-07-11T23:59:59.000Z
Recent theories predict phase separation among orientationally disordered active particles whose propulsion speed decreases rapidly enough with density. Coarse-grained models of this process show time-reversal symmetry (detailed balance) to be restored for uniform states, but broken by gradient terms; hence detailed-balance violation is strongly coupled to interfacial phenomena. To explore the subtle generic physics resulting from such coupling we here introduce `Active Model B'. This is a scalar $\\phi^4$ field theory (or phase-field model) that minimally violates detailed balance via a leading-order square-gradient term. We find that this additional term has modest effects on coarsening dynamics, but alters the static phase diagram by creating a jump in (thermodynamic) pressure across flat interfaces. Both results are surprising, since interfacial phenomena are always strongly implicated in coarsening dynamics but are, in detailed-balance systems, irrelevant for phase equilibria.
Kühne, Thomas D
2012-01-01T23:59:59.000Z
Computer simulations and molecular dynamics in particular, is a very powerful method to provide detailed and essentially exact informations of classical many-body problems. With the advent of \\textit{ab-initio} molecular dynamics, where the forces are computed on-the-fly by accurate electronic structure calculations, the scope of either method has been greatly extended. This new approach, which unifies Newton's and Schr\\"odinger's equations, allows for complex simulations without relying on any adjustable parameter. This review is intended to outline the basic principles as well as a survey of the field. Beginning with the derivation of Born-Oppenheimer molecular dynamics, the Car-Parrinello method as well as novel hybrid scheme that unifies best of either approach are discussed. The predictive power is demonstrated by a series of applications ranging from insulators to semiconductors and even metals in condensed phases.
Heterophase liquid states: Thermodynamics, structure, dynamics
A. S. Bakai
2015-01-12T23:59:59.000Z
An overview of theoretical results and experimental data on the thermodynamics, structure and dynamics of the heterophase glass-forming liquids is presented. The theoretical approach is based on the mesoscopic heterophase fluctuations model (HPFM) developed within the framework of the bounded partition function approach. The Fischer cluster phenomenon, glass transition, liquid-liquid transformations, parametric phase diagram, cooperative dynamics and fragility of the glass-forming liquids is considered.
Transient stability enhancement of electric power generating systems by 120-degree phase rotation
Cresap, Richard L. (Portland, OR); Taylor, Carson W. (Portland, OR); Kreipe, Michael J. (Portland, OR)
1982-01-01T23:59:59.000Z
A method and system for enhancing the transient stability of an intertied three-phase electric power generating system. A set of power exporting generators (10) is connected to a set of power importing generators (20). When a transient cannot be controlled by conventional stability controls, and imminent loss of synchronism is detected (such as when the equivalent rotor angle difference between the two generator sets exceeds a predetermined value, such as 150 degrees), the intertie is disconnected by circuit breakers. Then a switch (30) having a 120-degree phase rotation, or a circuit breaker having a 120-degree phase rotation is placed in the intertie. The intertie is then reconnected. This results in a 120-degree reduction in the equivalent rotor angle difference between the two generator sets, making the system more stable and allowing more time for the conventional controls to stabilize the transient.
Auxiliary field Monte-Carlo simulation of strong coupling lattice QCD for QCD phase diagram
Terukazu Ichihara; Akira Ohnishi; Takashi Z. Nakano
2014-10-07T23:59:59.000Z
We study the QCD phase diagram in the strong coupling limit with fluctuation effects by using the auxiliary field Monte-Carlo method. We apply the chiral angle fixing technique in order to obtain finite chiral condensate in the chiral limit in finite volume. The behavior of order parameters suggests that chiral phase transition is the second order or crossover at low chemical potential and the first order at high chemical potential. Compared with the mean field results, the hadronic phase is suppressed at low chemical potential, and is extended at high chemical potential as already suggested in the monomer-dimer-polymer simulations. We find that the sign problem originating from the bosonization procedure is weakened by the phase cancellation mechanism; a complex phase from one site tends to be canceled by the nearest neighbor site phase as long as low momentum auxiliary field contributions dominate.
Double ionization of Helium from a phase space perspective
Elie Assémat; Shai Machnes; David Tannor
2015-02-18T23:59:59.000Z
The aim of this paper is two-fold. First, we present a phase space perspective on long range double ionization in a one dimensional model of helium. The dynamics is simulated with the periodic von Neumann (PvB) method, an exact quantum method based on a lattice of phase space Gaussians. Second, we benchmark the method by comparing to the Multiconfiguration Time-dependent Hartree method. The PvB approach is found to be faster than the standard MCTDH code for the dynamics calculations and to give better accuracy control.
Universal contact-line dynamics at the nanoscale
Marco Rivetti; Thomas Salez; Michael Benzaquen; Elie Raphaël; Oliver Bäumchen
2015-07-31T23:59:59.000Z
The relaxation dynamics of the contact angle between a viscous liquid and a smooth substrate is studied at the nanoscale. Through atomic force microscopy measurements of polystyrene nanostripes we monitor simultaneously the temporal evolution of the liquid-air interface as well as the position of the contact line. The initial configuration exhibits high curvature gradients and a non-equilibrium contact angle that drive liquid flow. Both these conditions are relaxed to achieve the final state, leading to three successive regimes along time: i) stationary-contact-line levelling; ii) receding-contact-line dewetting; iii) collapse of the two fronts. For the first regime, we reveal the existence of a self-similar evolution of the liquid interface, which is in excellent agreement with numerical calculations from a lubrication model. For different liquid viscosities and film thicknesses we provide evidence for a transition to dewetting featuring a universal critical contact angle and dimensionless time.
Dynamics of Block Copolymer Nanocomposites
Mochrie, Simon G. J.
2014-09-09T23:59:59.000Z
A detailed study of the dynamics of cadmium sulfide nanoparticles suspended in polystyrene homopolymer matrices was carried out using X-ray photon correlation spectroscopy for temperatures between 120 and 180 °C. For low molecular weight polystyrene homopolymers, the observed dynamics show a crossover from diffusive to hyper-diffusive behavior with decreasing temperatures. For higher molecular weight polystyrene, the nanoparticle dynamics appear hyper-diffusive at all temperatures studied. The relaxation time and characteristic velocity determined from the measured hyper-diffusive dynamics reveal that the activation energy and underlying forces determined are on the order of 2.14 × 10?19 J and 87 pN, respectively. We also carried out a detailed X-ray scattering study of the static and dynamic behavior of a styrene– isoprene diblock copolymer melt with a styrene volume fraction of 0.3468. At 115 and 120 °C, we observe splitting of the principal Bragg peak, which we attribute to phase coexistence of hexagonal cylindrical and cubic double- gyroid structure. In the disordered phase, above 130 °C, we have characterized the dynamics of composition fluctuations via X-ray photon correlation spectroscopy. Near the peak of the static structure factor, these fluctuations show stretched-exponential relaxations, characterized by a stretching exponent of about 0.36 for a range of temperatures immediately above the MST. The corresponding characteristic relaxation times vary exponentially with temperature, changing by a factor of 2 for each 2 °C change in temperature. At low wavevectors, the measured relaxations are diffusive with relaxation times that change by a factor of 2 for each 8 °C change in temperature.
Phase patterns of coupled oscillators with application to wireless communication
Arenas, A.
2008-01-02T23:59:59.000Z
Here we study the plausibility of a phase oscillators dynamical model for TDMA in wireless communication networks. We show that emerging patterns of phase locking states between oscillators can eventually oscillate in a round-robin schedule, in a similar way to models of pulse coupled oscillators designed to this end. The results open the door for new communication protocols in a continuous interacting networks of wireless communication devices.
Computational models for the berry phase in semiconductor quantum dots
Prabhakar, S., E-mail: rmelnik@wlu.ca; Melnik, R. V. N., E-mail: rmelnik@wlu.ca [M2NeT Lab, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON N2L 3C5 (Canada); Sebetci, A. [Department of Mechanical Engineering, Mevlana University, 42003, Konya (Turkey)
2014-10-06T23:59:59.000Z
By developing a new model and its finite element implementation, we analyze the Berry phase low-dimensional semiconductor nanostructures, focusing on quantum dots (QDs). In particular, we solve the Schrödinger equation and investigate the evolution of the spin dynamics during the adiabatic transport of the QDs in the 2D plane along circular trajectory. Based on this study, we reveal that the Berry phase is highly sensitive to the Rashba and Dresselhaus spin-orbit lengths.
Analytically expressed constraint on two Majorana phases in neutrinoless double beta decay
Maedan, Shinji
2014-01-01T23:59:59.000Z
We assume that neutrinoless double beta decay is caused by the exchange of three light Majorana neutrinos. Under this assumption, we obtain, by the method of perturbation, the equation representing the isocontour of effective Majorana mass which is the function of two CP-violating Majorana phases. The equation representing the isocontour (constraint equation between two Majorana phases) is expressed analytically by six parameters: two lepton mixing angles, two kinds of neutrino mass squared differences, lightest neutrino mass scale, and the effective Majorana mass. We discuss how the constraint equation between two Majorana phases changes when the lightest neutrino mass scale is varied.
The effect of power line phase current correlation on magnetic field statistics
Dabkowski, J. [Electro Sciences, Inc., Crystal Lake, IL (United States)
1995-09-01T23:59:59.000Z
Due to normally occurring line currents unbalance, the magnetic field strength will fluctuate in time. The minimum field occurs when the phase currents are balanced, i.e. equal in magnitude and equally spaced in angle. The maximum field levels are obtained when the line currents` fluctuations are statistically independent, and hence, uncorrelated. It is shown that the earth return current due to the unbalance, and therefore, the strength of the magnetic field variations are a function of the line`s phase currents correlation. Power lines whose phase currents are highly correlated will produce a smaller increase in the magnetic field levels for a given percentage of current unbalance.
Yang, Chan-Shan [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Tang, Tsung-Ta [Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan (China); Pan, Ru-Pin [Department of Electrophysics, National Chiao Tung University, Hsinchu 30078, Taiwan (China); Yu, Peichen [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Pan, Ci-Ling, E-mail: clpan@phys.nthu.edu.tw [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Frontier Research Center on Fundamental and Applied Science of Matters, Hsinchu 30013, Taiwan (China)
2014-04-07T23:59:59.000Z
Indium Tin Oxide (ITO) nanowhiskers (NWhs) obliquely evaporated by electron-beam glancing-angle deposition can serve simultaneously as transparent electrodes and alignment layer for liquid crystal (LC) devices in the terahertz (THz) frequency range. To demonstrate, we constructed a THz LC phase shifter with ITO NWhs. Phase shift exceeding ?/2 at 1.0 THz was achieved in a ?517??m-thick cell. The phase shifter exhibits high transmittance (?78%). The driving voltage required for quarter-wave operation is as low as 5.66?V (rms), compatible with complementary metal-oxide-semiconductor (CMOS) and thin-film transistor (TFT) technologies.
Molecular Dynamics Simulation of Homogeneous Crystal Nucleation in Polyethylene
Yi, Peng
Using a realistic united-atom force field, molecular dynamics simulations were performed to study homogeneous nucleation of the crystal phase at about 30% supercooling from the melts of n-pentacontahectane (C150) and a ...
Kaplan, A. F. H. [Department of Engineering Sciences and Mathematics, Lulea University of Technology, S-971 87 Lulea (Sweden)
2012-10-08T23:59:59.000Z
The modulation of the angle-dependent Fresnel absorptivity across wavy molten steel surfaces during laser materials processing, like drilling, cutting, or welding, has been calculated. The absorptivity is strongly altered by the grazing angle of incidence of the laser beam on the processing front. Owing to its specific Brewster-peak characteristics, the 10.64 {mu}m wavelength CO{sub 2}-laser shows an opposite trend with respect to roughness and angle-of-incidence compared to lasers in the wavelength range of 532-1070 nm. Plateaus or rings of Brewster-peak absorptivity can lead to hot spots on a wavy surface, often in close proximity to cold spots caused by shadow domains.
Laser warning receiver to identify the wavelength and angle of arrival of incident laser light
Sinclair; Michael B. (Albuquerque, NM); Sweatt, William C. (Albuquerque, NM)
2010-03-23T23:59:59.000Z
A laser warning receiver is disclosed which has up to hundreds of individual optical channels each optically oriented to receive laser light from a different angle of arrival. Each optical channel has an optical wedge to define the angle of arrival, and a lens to focus the laser light onto a multi-wavelength photodetector for that channel. Each multi-wavelength photodetector has a number of semiconductor layers which are located in a multi-dielectric stack that concentrates the laser light into one of the semiconductor layers according to wavelength. An electrical signal from the multi-wavelength photodetector can be processed to determine both the angle of arrival and the wavelength of the laser light.
Richard Beyer; Markus Franke; Hans Joachim Schöpe; Eckhard Bartsch; Thomas Palberg
2014-12-02T23:59:59.000Z
Hard spheres are a well recognized model system of statistical physics and soft condensed matter. Their crystallization behaviour has been intensively studied at the structural length scale by Bragg light scattering and/or high resolution microscopy. We here present an improved light scattering apparatus capable to perform simultaneous measurements in the Bragg scattering regime and in the small angle regime. We give an account of its construction and demonstrate its performance for several examples of hard sphere and attractive hard sphere suspensions. Comparison of small angle to Bragg data allows a calibration of the sequence of events in time. We show how important complementary information can be gained from the small angle studies e.g. on the immediate environment of the growing crystals or the global scale crystallite distribution. We further demonstrate that processes occurring on larger length scales have a significant influence on the crystallization kinetics and the final micro-structure.
G. Litak; T. Kaminski; J. Czarnigowski; A. K. Sen; M. Wendeker
2006-11-29T23:59:59.000Z
In this paper we analyze the cycle-to-cycle variations of maximum pressure $p_{max}$ and peak pressure angle $\\alpha_{pmax}$ in a four-cylinder spark ignition engine. We examine the experimental time series of $p_{max}$ and $\\alpha_{pmax}$ for three different spark advance angles. Using standard statistical techniques such as return maps and histograms we show that depending on the spark advance angle, there are significant differences in the fluctuations of $p_{max}$ and $\\alpha_{pmax}$. We also calculate the multiscale entropy of the various time series to estimate the effect of randomness in these fluctuations. Finally, we explain how the information on both $p_{max}$ and $\\alpha_{pmax}$ can be used to develop optimal strategies for controlling the combustion process and improving engine performance.
Davis, Benjamin L; Shields, Douglas W; Kennefick, Julia; Kennefick, Daniel; Seigar, Marc S; Lacy, Claud H S; Puerari, Ivânio
2012-01-01T23:59:59.000Z
A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have been almost exclusively qualitative. We have developed a methodology, utilizing two-dimensional fast Fourier transformations of images of spiral galaxies, in order to isolate and measure the pitch angles of their spiral arms. Our technique provides a quantitative way to measure this morphological feature. This will allow comparison of spiral galaxy pitch angle to other galactic parameters and test spiral arm genesis theories. In this work, we detail our image processing and analysis of spiral galaxy images and discuss the robustness of our analysis techniques.
A Characterization of the Convexity of Cyclic Polygons in Terms of the Central Angles
Iosif Pinelis
2006-09-25T23:59:59.000Z
Let P be a cyclic n-gon with n\\ge3, the central angles \\th_0,...,\\th_{n-1} in (-\\pi,\\pi], and the winding number w:=(\\th_0+...+\\th_{n-1})/(2\\pi). The vertices of P are assumed to be all distinct from one another. It is then proved that P is convex if and only if one of the following four conditions holds: (I) w=1 and \\th_0,...,\\th_{n-1}>0; (II) w=-1 and \\th_0,...,\\th_{n-1}<0; (III) w=0 and exactly one of the angles \\th_0,...,\\th_{n-1} is negative; (IV) w=0 and exactly one of the angles \\th_0,...,\\th_{n-1} is positive.
Pickel, Deanna L [ORNL; Kilbey, II, S Michael [ORNL; Uhrig, David [ORNL; Hong, Kunlun [ORNL; Carrillo, Jan-Michael Y [ORNL; Sumpter, Bobby G [ORNL; Ahn, Suk-Kyun [ORNL; Han, Youngkyu [ORNL; Kim, Dr. Tae-Hwan [Korea Atomic Energy Research Institute; Smith, Gregory Scott [ORNL; Do, Changwoo [ORNL
2014-01-01T23:59:59.000Z
Structural evolution from poly(lactide) (PLA) macromonomer to resultant PLA molecular bottlebrush during ring opening metathesis polymerization (ROMP) was investigated for the first time by combining size exclusion chromatography (SEC), small-angle neutron scattering (SANS) and coarse-grained molecular dynamics (CG-MD) simulations. Multiple aliquots were collected at various reaction times during ROMP, and subsequently analyzed by SEC and SANS. The two complementary techniques enable the understanding of systematic changes in conversion, molecular weight and dispersity as well as structural details of PLA molecular bottlebrushes. CG-MD simulation not only predicts the experimental observations, but it also provides further insight into the analysis and interpretation of data obtained in SEC and SANS experiments. We find that PLA molecular bottlebrushes undergo three conformational transitions with increasing conversion (i.e., increasing the backbone length): (1) from an elongated to a globular shape due to longer side chain at lower conversion, (2) from a globular to an elongated shape at intermediate conversion caused by excluded volume of PLA side chain, and (3) the saturation of contour length at higher conversion due to chain transfer reactions.
Jain, Dr Nirmesh [University of Sydney, Australia] [University of Sydney, Australia; Liu, Dr C K [Institute of Materials research and Engineering, A-STAR, Singapore] [Institute of Materials research and Engineering, A-STAR, Singapore; Hawkett, Dr B. S. [University of Sydney, Australia] [University of Sydney, Australia; Warr, G. G. [University of Sydney, Australia] [University of Sydney, Australia; Hamilton, William A [ORNL] [ORNL
2014-01-01T23:59:59.000Z
The optical magnetic chaining technique (MCT) developed by Leal-Calderon, Bibette and co-workers in the 1990 s allows precise measurements of force profiles between droplets in monodisperse ferrofluid emulsions. However, the method lacks an in-situ determination of droplet size and therefore requires the combination of separately acquired measurements of droplet chain periodicity versus an applied magnetic field from optical Bragg scattering and droplet diameter inferred from dynamic light scattering (DLS) to recover surface force-distance profiles between the colloidal particles. Compound refractive lens (CRL) focussed small-angle scattering (SANS) MCT should result in more consistent measurements of droplet size (form factor measurements in the absence of field) and droplet chaining period (from structure factor peaks when the magnetic field is applied); and, with access to shorter length scales, extend force measurements to closer approaches than possible by optical measurements. We report on CRL-SANS measurements of monodisperse ferrofluid emulsion droplets aligned in straight chains by an applied field perpendicular to the incident beam direction. Analysis of the scattering from the closely spaced droplets required algorithms that carefully treated resolution and its effect on mean scattering vector magnitudes in order to determine droplet size and chain periods to sufficient accuracy. At lower applied fields scattering patterns indicate structural correlations transverse to the magnetic field direction due to the formation of intermediate structures in early chain growth.
Cirrus Microphysical Properties from Stellar Aureole Measurements, Phase I
DeVore, J. G.; Kristl, J. A.; Rappaport, S. A.
2012-04-20T23:59:59.000Z
While knowledge of the impact of aerosols on climate change has improved significantly due to the routine, ground-based, sun photometer measurements of aerosols made at AERONET sites world-wide, the impact of cirrus clouds remains much less certain because they occur high in the atmosphere and are more difficult to measure. This report documents work performed on a Phase I SBIR project to retrieve microphysical properties of cirrus ice crystals from stellar aureole imagery. The Phase I work demonstrates that (1) we have clearly measured stellar aureole profiles; (2) we can follow the aureole profiles out to ~1/4 degree from stars (~1/2 degree from Jupiter); (3) the stellar aureoles from cirrus have very distinctive profiles, being flat out to a critical angle, followed by a steep power-law decline with a slope of ~-3; (4) the profiles are well modeled using exponential size distributions; and (5) the critical angle in the profiles is ~0.12 degrees, (6) indicating that the corresponding critical size ranges from ~150 to ~200 microns. The stage has been set for a Phase II project (1) to proceed to validating the use of stellar aureole measurements for retrieving cirrus particle size distributions using comparisons with optical property retrievals from other, ground-based instruments and (2) to develop an instrument for the routine, automatic measurement of thin cirrus microphysical properties.
The Cabibbo angle as a universal seed for quark and lepton mixings
S. Roy; S. Morisi; N. N. Singh; J. W. F. Valle
2014-10-14T23:59:59.000Z
A model-independent ansatz to describe lepton and quark mixing in a unified way is suggested based upon the Cabibbo angle. In our framework neutrinos mix in a "Bi-Large" fashion, while the charged leptons mix as the "down-type" quarks do. In addition to the standard Wolfenstein parameters (lambda, A) two other free parameters are needed to specify the physical lepton mixing matrix. Through this simple assumption one makes specific predictions for the atmospheric angle as well as leptonic CP violation in good agreement with current observations.
The effects of sound on the boundary layer of an airfoil at high angles of attack
Hutchinson, Thomas Ira
1963-01-01T23:59:59.000Z
THE EFFECTS OF SOUND ON THE BOUNDARY LAYER OF AN AIRFOIL AT HIGH ANGLES OF ATTACK A Thesis By THOMAS IRA HUTCHINSON S, rhr?tted to the Graduate School of the Agrtcultu, al and Mechanical College of Texas in partial f, . lfrllr:, cnt... of the requirements for the degree of MASTER OF SCIENCE January 1963 Mai"" Subject: Acrcspace Engrneering THE EFFECTS OF SOUND ON THE BOUNDARY LAYER OF AN AIRFOIL AT HIGH ANGLES OF ATTACK A Thesis THOMAS IRA HUTCHINSON Approved as to style and content by...
Cosmic-ray pitch-angle scattering in imbalanced MHD turbulence simulations
Weidl, Martin S; Teaca, Bogdan; Schlickeiser, Reinhard
2015-01-01T23:59:59.000Z
Pitch-angle scattering rates for cosmic-ray particles in magnetohydrodynamic (MHD) simulations with imbalanced turbulence are calculated for fully evolving electromagnetic turbulence. We compare with theoretical predictions derived from the quasilinear theory of cosmic-ray diffusion for an idealized slab spectrum and demonstrate how cross helicity affects the shape of the pitch-angle diffusion coefficient. Additional simulations in evolving magnetic fields or static field configurations provide evidence that the scattering anisotropy in imbalanced turbulence is not primarily due to coherence with propagating Alfven waves, but an effect of the spatial structure of electric fields in cross-helical MHD turbulence.
Consideration of air jet angle in open surface tank push-pull ventilation system design
Chan, Wai-Hung David
1983-01-01T23:59:59.000Z
CONSIDERATION OF AIR JET ANGLE IN OPEN SURFACE TANK PUSH-PULL VENTILATION SYSTEM DESIGN A Thesis by WAI-HUNG DAVID CHAN Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree o... MASTER OF SCIENCE May 1983 Major Subjeot: Industrial Hygiene CONSIDERATION OF AIR JET ANGLE IN OPEN SURFACE TANK PUSH-PULL VENTILATION STSTEM DESIGN A Thesis by WAI-HUNG DAVID CHAN Approved as to style and content by: (C an of mmittee) J. Suggs...
Estimation of the Majorana phases using rephasing invariant quantities
Samanta, Rome; Ghosal, Ambar
2015-01-01T23:59:59.000Z
We estimate the Majorana phases for a general $3\\times3$ complex symmetric neutrino mass matrix on the basis of Mohapatra-Rodejohann's phase convention using the three rephasing invariant quantities $I_{12}$,$I_{13}$ and $I_{23}$ constructed out of the mass matrix elements. Such a model independent approach allows us to evaluate each Majorana phase even if one eigenvalue is zero. Utilizing the solution of a general complex symmetric mass matrix for eigenvalues and mixing angles we determine the Majorana phases for both the hierarchies, normal and inverted, taking into account the constraints from neutrino oscillation global fit data as well as bound on the sum of the three light neutrino masses. The allowed ranges of the Majorana phases ($\\alpha,\\beta+\\delta$) are obtained as $-78^o<\\alpha<77.5^o$,$-47^o<\\beta+\\delta<46.8^o$ for normal hierarchy and $-41.4^o<\\alpha<41.8^o$,$-54.2^o<\\beta+\\delta<53.2^0$ for inverted hierarchy. This generalized methodology of finding the Majorana phases ...
Mohammed Filali; Raymond Aznar; Mattias Svenson; Gregoire Porte; Jacqueline Appell
2004-10-12T23:59:59.000Z
In this paper we examine the effective interactions introduced between the droplets of an oil in water microemulsion upon progressive addition of hydrophobically modified water soluble poly(ethylene oxide)-PEO using essentially small angle neutron scattering. To discuss the relative importance of decoration and bridging of the droplets we compare analogous samples with addition of a PEO grafted at both extremities with hydrophobic C12H 25 chains (PEO-2m) or addition of a PEO grafted at one extremity only with a C12H 25 chain (PEO-m). PEO-m or PEO-2m adsorb onto the droplets via their hydrophobic extremities and the droplets are found to retain their form and size upon addition of up to 40 hydrophobic C12H 25 chains per droplet. When the volume fraction of droplets is less than about 10%, the effective interactions introduced by PEO-m or PEO-2m are found to be very different: PEO-m introduces a repulsive interaction while PEO-2m introduces an effective attractive interaction. This attractive interaction leads to an associative phase separation in the range of low volume fraction when a sufficient amount of PEO-2m is added.
Introduction to Dynamic Distributed
Roma "La Sapienza", Università di
Introduction to Dynamic Distributed SystemsSystems #12;Outline Introduction Churn Building Applications in Dynamic Distributed Systems RegistersRegisters Eventual Leader election Connectivity in Dynamic Distributed Systems #12;Dynamic Distributed Systems: Context & Motivations Advent of Complex Distributed
Michael Murray; for the BRAHMS Collaboration
2007-10-24T23:59:59.000Z
The purpose of BRAHMS is to survey the dynamics of relativistic heavy ion (as well as pp and d-A) collisions over a very wide range of rapidity and transverse momentum. The sum of these data may give us a glimpse of the initial state of the system, its transverse and longitudinal evolution and how the nature of the system changes with time. Here I will concentrate on the origin and dynamics of the light flavors, i.e. the creation and transport of the up, down and strange quarks. The results presented here are certainly not the end of the story. It is my hope that in a few years new detectors will reveal the rapidity dependence of the charm and bottom quarks.
Wen Yu; Kevin B. Wood
2015-03-19T23:59:59.000Z
We study the dynamics of phase synchronization in growing populations of discrete phase oscillatory systems when the division process is coupled to the distribution of oscillator phases. Using mean field theory, linear stability analysis, and numerical simulations, we demonstrate that coupling between population growth and synchrony can lead to a wide range of dynamical behavior, including extinction of synchronized oscillations, the emergence of asynchronous states with unequal state (phase) distributions, bistability between oscillatory and asynchronous states or between two asynchronous states, a switch between continuous (supercritical) and discontinuous (subcritical) transitions, and modulation of the frequency of bulk oscillations.
Dynamics of sliding drops on superhydrophobic surfaces
A. Dupuis; J. M. Yeomans
2006-05-10T23:59:59.000Z
We use a free energy lattice Boltzmann approach to investigate numerically the dynamics of drops moving across superhydrophobic surfaces. The surfaces comprise a regular array of posts small compared to the drop size. For drops suspended on the posts the velocity increases as the number of posts decreases. We show that this is because the velocity is primarily determined by the contact angle which, in turn, depends on the area covered by posts. Collapsed drops, which fill the interstices between the posts, behave in a very different way. The posts now impede the drop behaviour and the velocity falls as their density increases.
2010-08-05T23:59:59.000Z
pplane8 Phase Portraits. • The routine pplane8 is already loaded on all ITaP machines as standard software. (If you are using your own copy of MAtlAB you may ...
Protein viscoelastic dynamics: a model system
Craig Fogle; Joseph Rudnick; David Jasnow
2015-02-02T23:59:59.000Z
A model system inspired by recent experiments on the dynamics of a folded protein under the influence of a sinusoidal force is investigated and found to replicate many of the response characteristics of such a system. The essence of the model is a strongly over-damped oscillator described by a harmonic restoring force for small displacements that reversibly yields to stress under sufficiently large displacement. This simple dynamical system also reveals unexpectedly rich behavior, exhibiting a series of dynamical transitions and analogies with equilibrium thermodynamic phase transitions. The effects of noise and of inertia are briefly considered and described.
Brizard, Alain J. [Department of Physics, Saint Michael's College, Colchester, Vermont 05439 (United States); Guillebon, Loiec de [Centre de Physique Theorique Aix-Marseille Universite, CNRS (UMR 7332), 13288 Marseille Cedex 09 (France)
2012-09-15T23:59:59.000Z
The geometric analysis of the gyromotion for charged particles in a time-dependent magnetic field by Liu and Qin [Phys. Plasmas 18, 072505 (2011)] is reformulated in terms of the spatial angles that represent the instantaneous orientation of the magnetic field. This new formulation, which includes the equation of motion for the pitch angle, clarifies the decomposition of the gyroangle-averaged equation of motion for the gyrophase into its dynamic and geometric contributions.
Notes 10. The dynamic vibration absorber
San Andres, Luis
2008-01-01T23:59:59.000Z
-1 and the phase angle ? is zero degrees for excitation frequencies (?) natural frequency, and ?=-90 degrees for ? = natural frequency. ? s F o K p :=with X p t() ? s 1 r 2 ? () cos ? t? () ?= ? s 1 r 2 ? cos ? t...? ?+ () ?= [4] Thus, the periodic force response of the system (Kp,Mp) is : [3] as the frequency ratior ? ? np =with: Z p r() F o K p 1 r 2 ? () := or Zp F o K p ? 2 M p ??() = K p ? 2 M p ??()Zp? F o = Substitution of [2] into [1] gives: [2] Luis San Andres (c...
Electron microscope phase enhancement
Jin, Jian; Glaeser, Robert M.
2010-06-15T23:59:59.000Z
A microfabricated electron phase shift element is used for modifying the phase characteristics of an electron beam passing though its center aperture, while not affecting the more divergent portion of an incident beam to selectively provide a ninety-degree phase shift to the unscattered beam in the back focal plan of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. One application of the element is to increase the contrast of an electron microscope for viewing weakly scattering samples while in focus. Typical weakly scattering samples include biological samples such as macromolecules, or perhaps cells. Preliminary experimental images demonstrate that these devices do apply a ninety degree phase shift as expected. Electrostatic calculations have been used to determine that fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature-size aperture is about 5:1. Calculations are underway to determine the feasibility of aspect smaller aspect ratios of about 3:1 and about 2:1.
Llope, William J.
13th Winter Workshop on Nuclear Dynamics W.J. Llope Marathon Key, Florida, February 1Â8, 1997 RiceV/u 250 GeV Luminosity 2Ã?10 26 /cm 2 /s 1.4Ã?10 31 /cm 2 /s #12; 13th Winter Workshop on Nuclear Dynamics W hadrons and leptons in selected solid angles #12; 13th Winter Workshop on Nuclear Dynamics W.J. Llope
Micellar structure from comparison of X-ray and neutron small-angle scattering
Boyer, Edmond
249 Micellar structure from comparison of X-ray and neutron small-angle scattering T. Zemb and P according to the method developed by Hayter and Penfold. Both X-ray and neutron scattering signals, or by a combination of both. It has been shown recent- ly [1, 2] that it is possible in neutron scattering studies
Watson, Craig A.
Marine and freshwater fish support important angling industries that provide substantial benefit, it is important to evaluate how different stressors associated with this type of fishing affect fish survival. What follows is a brief Q & A review on the effects of air exposure. How long can a fish live out
Experimental demonstration of enhanced photon recycling in angle-restricted GaAs solar cells
Faraon, Andrei
Experimental demonstration of enhanced photon recycling in angle-restricted GaAs solar cells Emily, emphasizing the optical nature of the effect. 1 Introduction For ideal solar cells where all recombination. Despite this theoretical prediction, until recently even the highest efficiency solar cells were not close
Eddy current coil interaction with a right-angled conductive wedge
Bowler, John R.
Eddy current coil interaction with a right-angled conductive wedge BY T. P. THEODOULIDIS 1 AND J. R: eddy current; conductive wedge; coil impedance 1. Introduction The quasi-static electromagnetic field whose axis is normal to one of the wedge faces. The problem has applications in eddy current non
Transformation optofluidics for large-angle light bending and tuning{{ L. K. Chin,a
Zheludev, Nikolay
Transformation optofluidics for large-angle light bending and tuning{{ Y. Yang,*a L. K. Chin,a J. M DOI: 10.1039/c2lc40442g Transformation optics is a new art of light bending by designing materials with spatially variable parameters for developing wave-manipulation devices. Here, we introduce a transformation
Irena : tool suite for modeling and analysis of small-angle scattering.
Ilavsky, J.; Jemian, P.
2009-04-01T23:59:59.000Z
Irena, a tool suite for analysis of both X-ray and neutron small-angle scattering (SAS) data within the commercial Igor Pro application, brings together a comprehensive suite of tools useful for investigations in materials science, physics, chemistry, polymer science and other fields. In addition to Guinier and Porod fits, the suite combines a variety of advanced SAS data evaluation tools for the modeling of size distribution in the dilute limit using maximum entropy and other methods, dilute limit small-angle scattering from multiple non-interacting populations of scatterers, the pair-distance distribution function, a unified fit, the Debye-Bueche model, the reflectivity (X-ray and neutron) using Parratt's formalism, and small-angle diffraction. There are also a number of support tools, such as a data import/export tool supporting a broad sampling of common data formats, a data modification tool, a presentation-quality graphics tool optimized for small-angle scattering data, and a neutron and X-ray scattering contrast calculator. These tools are brought together into one suite with consistent interfaces and functionality. The suite allows robust automated note recording and saving of parameters during export.
Fiber optic temperature sensor using a grating on an angled fiber tip
Varadarajan, Harini
2000-01-01T23:59:59.000Z
A fiber optic temperature sensor intended to sense temperatures up to 1400°C was investigated experimentally. A key element of the sensor is a grating on the 45°-angled tip of a single mode fiber. When light propagating in the fiber reaches the tip...
Near-Infrared Surface Plasmon Resonance Measurements of Ultrathin Films. 1. Angle Shift
Near-Infrared Surface Plasmon Resonance Measurements of Ultrathin Films. 1. Angle Shift and SPR-1396 The application of surface plasmon resonance (SPR) measurements to the study of ultrathin organic and inorganic. One disadvantage of using NIR wavelengths for SPR imaging is that the surface plasmon propagation
Chen, Sow-Hsin
Neutron Scattering Yun Liu,1 Emiliano Fratini,2 Piero Baglioni,1,2 Wei-Ren Chen,1 and Sow-Hsin Chen1,* 1, Italy (Received 8 February 2005; published 8 September 2005) Small angle neutron scattering intensity neutron and x-ray scattering investigations of proteins suggest the presence of a short-range attractive
Fiber optic temperature sensor using a grating on an angled fiber tip
Varadarajan, Harini
2000-01-01T23:59:59.000Z
A fiber optic temperature sensor intended to sense temperatures up to 1400°C was investigated experimentally. A key element of the sensor is a grating on the 45°-angled tip of a single mode fiber. When light propagating in the fiber reaches the tip...
Liquid Crystal Pretilt and Azimuth Angle Study of Stacked Alignment Layers
angles for the liquid crystal. It is based on stacking both photo- aligned polymer and rubbed polyimide comprise of both photo-aligned horizontal polymer and rubbed vertical polyimide. The advantage alignment polyimide JALS2021 form JSR Corporation is spin coated on the substrate. Then it is baked inside
Dooraghi, M.; Habte, A.; Reda, I.; Sengupta, M.; Gotseff, P.; Andreas, A.; Anderberg, M.
2014-03-01T23:59:59.000Z
This poster seeks to demonstrate the importance and application of an existing but unused approach that ultimately reduces the uncertainty of radiometric measurements. Current radiometric data is based on a single responsivity value that introduces significant uncertainty to the data, however, through using responsivity as a function of solar zenith angle, the uncertainty could be decreased by 50%.
Computing Neck-Shaft Angle of Femur for X-Ray Fracture Detection
Leow, Wee Kheng
Computing Neck-Shaft Angle of Femur for X-Ray Fracture Detection Tai Peng Tian1 , Ying Chen1 , Wee and 13% of men suffer from osteoporotic fractures of the bone, particularly the older people. Doctors in the hospitals need to manually inspect a large number of x-ray im- ages to identify the fracture cases
Chan, Derek Y C
van der Waals Interaction, Surface Free Energies, and Contact Angles: Dispersive Polymers and Liquids Calum J. Drummond*, and Derek Y. C. Chan CSIRO Division of Chemicals and Polymers, Private Bag 10 and ALVL are the non-retarded Hamaker constants for the heterointeraction between polymer and liquid across
Valley-Dependent Brewster Angles and Goos-Hanchen Effect in Strained Graphene Zhenhua Wu,1
Valley-Dependent Brewster Angles and Goos-HaÂ¨nchen Effect in Strained Graphene Zhenhua Wu,1 F. Zhai local strains in graphene can be tailored to generate a valley- polarized current. By suitable be used to construct a valley filter in graphene without the need for any external fields. DOI: 10
Hu, Jian Zhi (Richland, WA); Sears, Jr., Jesse A. (Kennewick, WA); Hoyt, David W. (Richland, WA); Wind, Robert A. (Kennewick, WA)
2009-05-19T23:59:59.000Z
Described are a "Discrete Magic Angle Turning" (DMAT) system, devices, and processes that combine advantages of both magic angle turning (MAT) and magic angle hopping (MAH) suitable, e.g., for in situ magnetic resonance spectroscopy and/or imaging. In an exemplary system, device, and process, samples are rotated in a clockwise direction followed by an anticlockwise direction of exactly the same amount. Rotation proceeds through an angle that is typically greater than about 240 degrees but less than or equal to about 360 degrees at constant speed for a time applicable to the evolution dimension. Back and forth rotation can be synchronized and repeated with a special radio frequency (RF) pulse sequence to produce an isotropic-anisotropic shift 2D correlation spectrum. The design permits tubes to be inserted into the sample container without introducing plumbing interferences, further allowing control over such conditions as temperature, pressure, flow conditions, and feed compositions, thus permitting true in-situ investigations to be carried out.
Devices and process for high-pressure magic angle spinning nuclear magnetic resonance
Hoyt, David W; Sears, Jr., Jesse A; Turcu, Romulus V.F.; Rosso, Kevin M; Hu, Jian Zhi
2014-04-08T23:59:59.000Z
A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.