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.
Angle of Arrival Detection with Fifth Order Phase Operators
Khmou, Youssef
2015-01-01T23:59:59.000Z
In this paper, a fifth order propagator operators are proposed for estimating the Angles Of Arrival (AOA) of narrowband electromagnetic waves impinging on antenna array when its number of sensors is larger than the number of radiating sources. The array response matrix is partitioned into five linearly dependent phases to construct the noise projector using five different propagators from non diagonal blocks of the spectral matrice of the received data; hence, five different estimators are proposed to estimate the angles of the sources. The simulation results proved the performance of the proposed estimators in the presence of white noise comparatively to high resolution eigen based spectra.
Flat Lens Criterion by Small-Angle Phase
Ott, Peter; Lezec, Henri J; Chau, Kenneth J
2015-01-01T23:59:59.000Z
We show that a classical imaging criterion based on angular dependence of small-angle phase can be applied to any system composed of planar, uniform media to determine if it is a flat lens capable of forming a real paraxial image and to estimate the image location. The real paraxial image location obtained by this method shows agreement with past demonstrations of far-field flat-lens imaging and can even predict the location of super-resolved images in the near-field. The generality of this criterion leads to several new predictions: flat lenses for transverse-electric polarization using dielectric layers, a broadband flat lens working across the ultraviolet-visible spectrum, and a flat lens configuration with an image plane located up to several wavelengths from the exit surface. These predictions are supported by full-wave simulations. Our work shows that small-angle phase can be used as a generic metric to categorize and design flat lenses.
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,
angle spinning dynamic: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Quantization of this model is briefly discussed. S. A. Pol'shin 2011-10-24 87 Dynamics of artificial spin ice: a continuous honeycomb network MIT - DSpace Summary: We model the...
Phase Angle Effects on 3-micron Absorption Band on Ceres: Implications for Dawn Mission
Takir, Driss; Sanchez, Juan A; Corre, Lucille Le; Hardersen, Paul S; Nathues, Andreas
2015-01-01T23:59:59.000Z
Phase angle-induced spectral effects are important to characterize since they affect spectral band parameters such as band depth and band center, and therefore skew mineralogical interpretations of planetary bodies via reflectance spectroscopy. Dwarf planet (1) Ceres is the next target of NASA's Dawn mission, which is expected to arrive in March 2015. The visible and near-infrared mapping spectrometer (VIR) onboard Dawn has the spatial and spectral range to characterize the surface between 0.25-5.0 microns. Ceres has an absorption feature at 3.0 microns due to hydroxyl- and/or water-bearing minerals (e.g. Lebofsky et al. 1981, Rivkin et al. 2003). We analyzed phase angle-induced spectral effects on the 3-micron absorption band on Ceres using spectra measured with the long-wavelength cross-dispersed (LXD: 1.9-4.2 microns) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility (IRTF). Ceres LXD spectra were measured at different phase angles ranging from 0.7o to 22o. We found that the band...
Floating Offshore Wind Turbine Dynamics: Large-Angle Motions in Euler-Space
Sweetman, Bert
wind turbines in deep water, where environmental forcing could subject the rotor to meaningful angular relative to (X,Y,Z) CT Thrust coefficient, used to calculate wind force on the blade swept area 1Floating Offshore Wind Turbine Dynamics: Large-Angle Motions in Euler-Space Bert Sweetman Texas A
Power reduction by balancing sucker rod pumping unit with weight induced phase angle
Noack, Ernest Alan
1991-01-01T23:59:59.000Z
dynamometer. This method gives quick and reliable information which aids in obtaining the proper counterbalance. This method is enhanced by the ability to vary the phase angle of the cranks by the use of the counter weights. This ability indicates... and knowledge in this subject. Jim McCoy, for the use of a computerized dynamometer which made this research possible. Cecil Hunt and Sam Gandy for their help in accumulating vendor data and for their many helpful suggestions. Bob Gault for his knowledge...
White, Anne E.
This paper presents new measurements of the cross-phase angle, ?neTe [alpha n subscript n subscript e T subscript e], between long-wavelength (k??s<0.5) [k subscript theta p subscript s < 0.5)] density, n~e [n cedilla ...
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.
Quantum phases and dynamics of geometric phase in a quantum spin chain system under linear quench
Sujit Sarkar; B. Basu
2011-09-11T23:59:59.000Z
We study the quantum phases of anisotropic XY spin chain system in presence and absence of adiabatic quench. A connection between geometric phase and criticality is established from the dynamical behaviour of the geometric phase for a quench induced quantum phase transition in a quantum spin chain. We predict XX criticality associated with a sequence of non-contractible geometric phases.
Dynamic Phase Filtering with Integrated Optical Ring Resonators
Adams, Donald Benjamin
2011-10-21T23:59:59.000Z
can then help extract complex spectral information. Broadband photonic RF phase shifting for beam steering of a phased array antenna is also shown using dynamically tunable integrated optical ring resonators. Finally all-optical pulse compression...
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.
Zuch, Howard Weller
1959-01-01T23:59:59.000Z
LIBRARY A g M COLLEGE OF TEXAS A CALCULATION OF THE INDUCI'ANCE OF 3 ? PHASE BUSES COh6$ ISED OF SqUARE TUBULAR CONDUCTORS WITH 120-DEGREE-ANGLE S PAC ING A Thesis By Howard Wailer Zuch Submitted to ths Graduate School of the Agricultural... and Mechanical College of Texas in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE January 1959 Major Subject: Electrical Engineering A CAICULAT ION OF THE IMDUCTANCL' OF 3-PIIASI BUSES COMPR ISED OF SQUARE TUBULAR CONDUCTORS...
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 ...
Euclidean Dynamical Symmetry in Nuclear Shape Phase Transitions
Yu Zhang; Yu-Xin Liu; Feng Pan; Yang Sun; J. P. Draayer
2014-11-26T23:59:59.000Z
The Euclidean dynamical symmetry hidden in the critical region of nuclear shape phase transitions is revealed by a novel algebraic F(5) description. With a nonlinear projection, it is shown that the dynamics in the critical region of the spherical--axial deformed and the spherical--$\\gamma$ soft shape phase transitions can indeed be manifested by this description, which thus provides a unified symmetry--based interpretation of the critical phenomena in the region.
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 Boundaries for Compressible Fluids , Z. L. Xu
New York at Stoney Brook, State University of
discontinuity. The emphasis here is on the coupling of the phase transition process to acoustic waves, whichDynamic Phase Boundaries for Compressible Fluids T. Lu Â§ , Z. L. Xu Â§ , R. SamulyakÂ§ , J. Glimm algorithm is verified by application to various physical regimes. 1 Introduction The coupling
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.
Decoherence in a dynamical quantum phase transition
Sarah Mostame; Gernot Schaller; Ralf Schützhold
2010-04-15T23:59:59.000Z
Motivated by the similarity between adiabatic quantum algorithms and quantum phase transitions, we study the impact of decoherence on the sweep through a second-order quantum phase transition for the prototypical example of the Ising chain in a transverse field and compare it to the adiabatic version of Grovers search algorithm, which displays a first order quantum phase transition. For site-independent and site-dependent coupling strengths as well as different operator couplings, the results show that (in contrast to first-order transitions) the impact of decoherence caused by a weak coupling to a rather general environment increases with system size (i.e., number of spins/qubits). This might limit the scalability of the corresponding adiabatic quantum algorithm.
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
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.
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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructureProposedPAGESafetyTed Donat AboutTextiles (2010 dynamics of
Geometric phase of a qubit driven by a phase noise laser under non-Markovian dynamics
Berrada, K., E-mail: kberrada@ictp.it
2014-01-15T23:59:59.000Z
Robustness of the geometric phase (GP) with respect to the environmental effects is a basic condition for an effective quantum computation. Here, we study quantitatively the GP of a two-level atom system driven by a phase noise laser under non-Markovian dynamics in terms of different parameters involved in the whole system. We find that with the change of the damping coupling, the GP is very sensitive to its properties exhibiting long collapse and revival phenomena, which play a significant role in enhancing the stabilization and control of the system dynamics. Moreover, we show that the GP can be considered as a tool for testing and characterizing the nature of the qubit–environment coupling. Due to the significance of how a system is quantum correlated with its environment in the construction of a scalable quantum computer, the entanglement dynamics between the qubit with its environment under external classical noise is evaluated and investigated during the time evolution. -- Highlights: •Geometric phase under noise phase laser. •Dynamics of the geometric phase under non-Markovian dynamics in the presence of classical noise. •Solution of master equation of the system in terms atomic inversion. •Nonlocal correlation between the system and its environment under non-Markovianity.
Mancini, Giulia Fulvia; Pennacchio, Francesco; Reguera, Javier; Stellacci, Francesco; Carbone, Fabrizio
2015-01-01T23:59:59.000Z
Metal nanoparticles (NPs) are promising candidates for applications from electronics to medicine. Their metallic core provides some key properties, e.g. magnetization, plasmonic response or conductivity, with the ligand molecules providing others like solubility, assembly or interaction with biomolecules. Even more properties can be engineered when these NPs are used as building blocks to form supracrystals. The formation of these supracrystals depends upon a complex interplay between many forces, some stemming from the core, some from the ligand. At present, there is no known approach to characterize the local order of ligand molecules in such complex supracrystals or their dynamics, with a spatial resolution ranging from the NPs cores and their ligands, to the larger scale domains arrangement. Here, we develop a methodology based on small-angle ultrafast electron diffraction to characterize different two-dimensional supracrystals of alkanethiol-coated gold nanoparticles with femtosecond time, sub-nanometer ...
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.
Nonlinear dynamics of phase-space zonal structures and energetic particle physics
Vlad, Gregorio
1 I-12 Nonlinear dynamics of phase-space zonal structures and energetic particle physics F. Zonca1 there is no time scale separation between nonlinear dynamics evolution of phase space structures and the wave- ear dynamics of phase space zonal structures are presented and compared, showing that frequency
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.
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
Atomistic simulation of structure and dynamics of columnar phases of hexabenzocoronene derivatives
Denis Andrienko; Valentina Marcon; Kurt Kremer
2006-07-27T23:59:59.000Z
Using atomistic molecular dynamics simulations we study solid and liquid crystalline columnar discotic phases formed by alkyl-substituted hexabenzocoronene mesogens. Correlations between the molecular structure, packing, and dynamical properties of these materials are established.
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
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.
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
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...
Phase-space dynamics of runaway electrons in tokamaks Xiaoyin Guan, Hong Qin, and Nathaniel J. Fisch
Phase-space dynamics of runaway electrons in tokamaks Xiaoyin Guan, Hong Qin, and Nathaniel J Received 9 February 2010; accepted 19 July 2010; published online 3 September 2010 The phase-space dynamics. A theoretical model and a numerical algorithm for the runaway dynamics in phase space are developed. Instead
Dynamic Phase Shifts in Nanoscale Distance Measurements by Double...
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by Double Electron Electron Resonance (DEER)† . Abstract: The off-resonant pump pulse used in double electron electron resonance (DEER) measurements produces dynamic...
Cheng, Yuan-Chung, Ph. D. Massachusetts Institute of Technology
2006-01-01T23:59:59.000Z
In this thesis, we develop analytical models for quantum systems and perform theoretical investigations on several dynamical processes in condensed phases. First, we study charge-carrier mobilities in organic molecular ...
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)
Dynamics of geometric phase in the adiabatic limit of quantum phase transition
B. Basu
2010-05-10T23:59:59.000Z
The geometric phase associated with a many body ground state exhibits a signature of quantum phase transition. In this context, we have studied the behaviour of the geometric phase during a linear quench caused by a gradual turning off of the magnetic field interacting with a spin chain.
Theory of universal fast orientational dynamics in the isotropic phase of liquid crystals
Fayer, Michael D.
is also capable of examining the short distance scale and short time scale dynamics, and yields universal dynamical behavior in the isotropic phase of liquid crystals on ultrafast time scales and short distance scales. The theoretical development generates a temperature independent power law for the short
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
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
arterial phase dynamic: Topics by E-print Network
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of PVT systems. In particular, we establish a new time-dependent Ginzburg-Landau model, whose dynamic transition analysis is carried out. It is worth pointing out that the...
Dynamics of two-cluster systems in phase space
Lashko, Yu A; Vasilevsky, V S
2015-01-01T23:59:59.000Z
We present a phase-space representation of quantum state vectors for two-cluster systems. Density distributions in the Fock--Bargmann space are constructed for bound and resonance states of $^{6,7}$Li and $^{7,8}$Be, provided that all these nuclei are treated within a microscopic two-cluster model. The density distribution in the phase space is compared with those in the coordinate and momentum representations. Bound states realize themselves in a compact area of the phase space, as also do narrow resonance states. We establish the quantitative boundaries of this region in the phase space for the nuclei under consideration. Quantum trajectories are demonstrated to approach their classical limit with increasing energy.
Dynamics of two-cluster systems in phase space
Yu. A. Lashko; G. F. Filippov; V. S. Vasilevsky
2015-03-20T23:59:59.000Z
We present a phase-space representation of quantum state vectors for two-cluster systems. Density distributions in the Fock--Bargmann space are constructed for bound and resonance states of $^{6,7}$Li and $^{7,8}$Be, provided that all these nuclei are treated within a microscopic two-cluster model. The density distribution in the phase space is compared with those in the coordinate and momentum representations. Bound states realize themselves in a compact area of the phase space, as also do narrow resonance states. We establish the quantitative boundaries of this region in the phase space for the nuclei under consideration. Quantum trajectories are demonstrated to approach their classical limit with increasing energy.
Phase Resetting Reveals Network Dynamics Underlying a Bacterial Cell Cycle
Scherer, Norbert F.
promoter to express the essential transcriptional regulatory gene ctrA in a periodic, pulsed fashion perturbation spectroscopy (CPS). Citation: Lin Y, Li Y, Crosson S, Dinner AR, Scherer NF (2012) Phase Resetting
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.
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
Shupe, Matthew D
2007-10-01T23:59:59.000Z
This final report summarizes the major accomplishments and products resulting from a three-year grant funded by the DOE, Office of Science, Atmospheric Radiation Measurement Program titled: An Investigation of the Microphysical, Radiative, and Dynamical Properties of Mixed-Phase Clouds. Accomplishments are listed under the following subcategories: Mixed-phase cloud retrieval method development; Mixed-phase cloud characterization; ARM mixed-phase cloud retrieval review; and New ARM MICROBASE product. In addition, lists are provided of service to the Atmospheric Radiation Measurement Program, data products provided to the broader research community, and publications resulting from this grant.
Molecular dynamics of gas phase hydrogen-bonded complexes
Wofford, Billy Alan
1987-01-01T23:59:59.000Z
. These analyses have permitted the calculation of an approximate stretching harmonic force field for the hydrogen-bound heterodimer HCN---HF. In addition, a new technique is developed to determine both the ground state and equilibrium dissociation energies... OF FIGURES. CHAPTER I. INTRODUCTION. CHAPTER II. MOLECULAR DYNAMICS IN HYDROGEN-BONDED INTERACTIONS: A PRELIMINARY EXPERIMENTALLY DETERMINED HARMONIC STRETCHING FORCE FIELD FOR HCN---HF. Introduction. Experimental Calculations. 10 Discussion. 19...
Phase dynamics of nearly stationary patterns in activator-inhibitor systems
Hagberg, Aric [Center for Nonlinear Studies and T-7, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Center for Nonlinear Studies and T-7, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Meron, Ehud [The Jacob Blaustein Institute for Desert Research and the Physics Department, Ben-Gurion University, Sede Boker Campus 84990, (Israel)] [The Jacob Blaustein Institute for Desert Research and the Physics Department, Ben-Gurion University, Sede Boker Campus 84990, (Israel); Passot, Thierry [Observatoire de la Cote d'Azur, Boite Postale 4229, 06304 Nice Cedex 4, (France) [Observatoire de la Cote d'Azur, Boite Postale 4229, 06304 Nice Cedex 4, (France); Department of Mathematics, University of Arizona, Tucson, Arizona 85721 (United States)
2000-06-01T23:59:59.000Z
The slow dynamics of nearly stationary patterns in a FitzHugh-Nagumo model are studied using a phase dynamics approach. A Cross-Newell phase equation describing slow and weak modulations of periodic stationary solutions is derived. The derivation applies to the bistable, excitable, and Turing unstable regimes. In the bistable case stability thresholds are obtained for the Eckhaus and zigzag instabilities and for the transition to traveling waves. Neutral stability curves demonstrate the destabilization of stationary planar patterns at low wave numbers to zigzag and traveling modes. Numerical solutions of the model system support the theoretical findings. (c) 2000 The American Physical Society.
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...
Rodriguez, E.; Rasmussen, B.
2015-01-01T23:59:59.000Z
1Supplemental Simulation Case Studies of Dynamic Evaporator Modeling Paradigms with Variable Fluid Phases Erik Rodriguez1, Bryan Rasmussen2 The purpose of this document is to present a multitude of case studies comparing evaporator modeling... 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...
Balasubramonian, Rajeev (Sandy, UT); Dwarkadas, Sandhya (Rochester, NY); Albonesi, David (Ithaca, NY)
2012-01-24T23:59:59.000Z
In a processor having multiple clusters which operate in parallel, the number of clusters in use can be varied dynamically. At the start of each program phase, the configuration option for an interval is run to determine the optimal configuration, which is used until the next phase change is detected. The optimum instruction interval is determined by starting with a minimum interval and doubling it until a low stability factor is reached.
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.
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.
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.
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.
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.
Phase space theory of quantum–classical systems with nonlinear and stochastic dynamics
Buri?, Nikola, E-mail: buric@ipb.ac.rs; Popovi?, Duška B.; Radonji?, Milan; Prvanovi?, Slobodan
2014-04-15T23:59:59.000Z
A novel theory of hybrid quantum–classical systems is developed, utilizing the mathematical framework of constrained dynamical systems on the quantum–classical phase space. Both, the quantum and classical descriptions of the respective parts of the hybrid system are treated as fundamental. Therefore, the description of the quantum–classical interaction has to be postulated, and includes the effects of neglected degrees of freedom. Dynamical law of the theory is given in terms of nonlinear stochastic differential equations with Hamiltonian and gradient terms. The theory provides a successful dynamical description of the collapse during quantum measurement. -- Highlights: •A novel theory of quantum–classical systems is developed. •Framework of quantum constrained dynamical systems is used. •A dynamical description of the measurement induced collapse is obtained.
Crossover of phase qubit dynamics in presence of negative-result weak measurement
Rusko Ruskov; Ari Mizel; Alexander N. Korotkov
2006-11-11T23:59:59.000Z
Coherent dynamics of a superconducting phase qubit is considered in the presence of both unitary evolution due to microwave driving and continuous non-unitary collapse due to negative-result measurement. In the case of a relatively weak driving, the qubit dynamics is dominated by the non-unitary evolution, and the qubit state tends to an asymptotically stable point on the Bloch sphere. This dynamics can be clearly distinguished from conventional decoherence by tracking the state purity and the measurement invariant (``murity''). When the microwave driving strength exceeds certain critical value, the dynamics changes to non-decaying oscillations: any initial state returns exactly to itself periodically in spite of non-unitary dynamics. The predictions can be verified using a modification of a recent experiment.
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.
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.
Ultrafast Dynamics and Phase Changes in Solids Excited by Femtosecond Laser Pulses
Mazur, Eric
Ultrafast Dynamics and Phase Changes in Solids Excited by Femtosecond Laser Pulses A thesis pulse excites 1Â20% of the valence electrons. We developed a broadband pump-probe technique to measure femtoseconds. The dielectric function provides more information than ever before on the ultrafast electronic
DYNAMIC TRACKING PHASED ARRAY DATA LINKS K. D. Brown Dr. Chris Allen
Kansas, University of
DYNAMIC TRACKING PHASED ARRAY DATA LINKS K. D. Brown Dr. Chris Allen NNSA-KCP University of Kansas link developed by National Nuclear Safety Administration's Kansas City Plant (NNSA-KCP) and the University of Kansas (KU) in support of NNSA's Remote Sensing Laboratory (NNSA-RSL) located at the Nevada
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
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 ...
Rossi, Mariana; Paesani, Francesco; Bowman, Joel; Ceriotti, Michele
2014-01-01T23:59:59.000Z
Including quantum mechanical effects on the dynamics of nuclei in the condensed phase is challenging, because the complexity of exact methods grows exponentially with the number of quantum degrees of freedom. Efforts to circumvent these limitations can be traced down to two approaches: methods that treat a small subset of the degrees of freedom with rigorous quantum mechanics, considering the rest of the system as a static or classical environment, and methods that treat the whole system quantum mechanically, but using approximate dynamics. Here we perform a systematic comparison between these two philosophies for the description of quantum effects in vibrational spectroscopy, taking the Embedded Local Monomer (LMon) model and a mixed quantum-classical (MQC) model as representatives of the first family of methods, and centroid molecular dynamics (CMD) and thermostatted ring polymer molecular dynamics (TRPMD) as examples of the latter. We use as benchmarks D$_2$O doped with HOD and pure H$_2$O at three distinc...
Phase space structures and ionization dynamics of hydrogen atom in elliptically polarized microwaves
Elena Shchekinova; Cristel Chandre; Turgay Uzer
2006-08-24T23:59:59.000Z
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 Poincar\\'{e} surfaces of section, impractical. We analyze the phase space dynamics using 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.
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.
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.
Classification of two dimensional fixed sun angle solar sail trajectories
Roberts, Mark
Classification of two dimensional fixed sun angle solar sail trajectories Stephen Wokes, Phil heliocentric trajectories for fixed sun angle solar sails are examined. The objective of this work (lightness factor) and Sun angle this phase space shows all possible solar sail trajectories. This phase
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.
Dynamics of two populations of phase oscillators with different frequency distributions
Yu Terada; Toshio Aoyagi
2014-11-19T23:59:59.000Z
A large variety of rhythms have been observed in nature. These rhythms can be often regarded to interact with each other, such as electroencephalogram (EEG) in the brain. To investigate the dynamical properties of such systems, in this paper, we consider two populations of phase oscillators with different frequency distributions, particularly under the condition that the average frequency of fast oscillators is almost equal to the integral multiple of that of slow oscillators. What is the most important point is that we have to use the specific type of the coupling function derived from the phase reduction theory. Under some additional assumption, moreover, we can reduce the system consisting of two populations of coupled phase oscillators to a low-dimensional system in the continuum limit. As a result, we find chimera states in which clustering and incoherent states coexist. We also confirm that the behaviors of the derived low-dimensional model fairly agree with that of the original one.
Index k saddles and dividing surfaces in phase space, with applications to isomerization dynamics
Collins, Peter; Wiggins, Stephen
2011-01-01T23:59:59.000Z
In this paper we continue our studies of the phase space geometry and dynamics associated with index k saddles (k > 1) of the potential energy surface. Using normal form theory, we give an explicit formula for a "dividing surface" in phase space, i.e. a co-dimension one surface (within the energy shell) through which all trajectories that "cross" the region of the index k saddle must pass. With a generic non-resonance assumption, the normal form provides k (approximate) integrals that describe the saddle dynamics in a neighborhood of the index k saddle. These integrals provide a symbolic description of all trajectories that pass through a neighborhood of the saddle. We give a parametrization of the dividing surface which is used as the basis for a numerical method to sample the dividing surface. Our techniques are applied to isomerization dynamics on a potential energy surface having 4 minima; two symmetry related pairs of minima are connected by low energy index one saddles, with the pairs themselves connect...
T. P. Shestakova
2014-06-12T23:59:59.000Z
We construct Hamiltonian dynamics of the generalized spherically symmetric gravitational model in extended phase space. We start from the Faddeev - Popov effective action with gauge-fixing and ghost terms, making use of gauge conditions in differential form. It enables us to introduce missing velocities into the Lagrangian and then construct a Hamiltonian function according a usual rule which is applied for systems without constraints. The main feature of Hamiltonian dynamics in extended phase space is that it can be proved to be completely equivalent to Lagrangian dynamics derived from the effective action. We find a BRST invariant form of the effective action by adding terms not affecting Lagrangian equations. After all, we construct the BRST charge according to the Noether theorem. Our algorithm differs from that by Batalin, Fradkin and Vilkovisky, but the resulting BRST charge generates correct transformations for all gravitational degrees of freedom including gauge ones. Generalized spherically symmetric model imitates the full gravitational theory much better then models with finite number of degrees of freedom, so that one can expect appropriate results in the case of the full theory.
Spatiotemporal dynamics of a digital phase-locked loop based coupled map lattice system
Banerjee, Tanmoy, E-mail: tbanerjee@phys.buruniv.ac.in; Paul, Bishwajit; Sarkar, B. C. [Department of Physics, University of Burdwan, Burdwan, West Bengal 713 104 (India)] [Department of Physics, University of Burdwan, Burdwan, West Bengal 713 104 (India)
2014-03-15T23:59:59.000Z
We explore the spatiotemporal dynamics of a coupled map lattice (CML) system, which is realized with a one dimensional array of locally coupled digital phase-locked loops (DPLLs). DPLL is a nonlinear feedback-controlled system widely used as an important building block of electronic communication systems. We derive the phase-error equation of the spatially extended system of coupled DPLLs, which resembles a form of the equation of a CML system. We carry out stability analysis for the synchronized homogeneous solutions using the circulant matrix formalism. It is shown through extensive numerical simulations that with the variation of nonlinearity parameter and coupling strength the system shows transitions among several generic features of spatiotemporal dynamics, viz., synchronized fixed point solution, frozen random pattern, pattern selection, spatiotemporal intermittency, and fully developed spatiotemporal chaos. We quantify the spatiotemporal dynamics using quantitative measures like average quadratic deviation and spatial correlation function. We emphasize that instead of using an idealized model of CML, which is usually employed to observe the spatiotemporal behaviors, we consider a real world physical system and establish the existence of spatiotemporal chaos and other patterns in this system. We also discuss the importance of the present study in engineering application like removal of clock-skew in parallel processors.
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
Coastal Dynamics 2013 A 3-D PHASE-AVERAGED MODEL FOR SHALLOW WATER FLOW WITH WAVES IN
US Army Corps of Engineers
Coastal Dynamics 2013 1915 A 3-D PHASE-AVERAGED MODEL FOR SHALLOW WATER FLOW WITH WAVES in coastal vegetated waters with short waves. The model adopts the 3-D phase-averaged shallow water flow mesh in the vertical direction. The flow model is coupled with a spectral wave deformation model called
New York at Stoney Brook, State University of
discontinuity. The emphasis here is on the coupling of the phase transition process to acoustic waves, whichDynamic Phase Boundaries for Compressible Fluids T. Lu Â§ , Z. L. Xu Â§+ , R. Samulyak Â§ , J. Glimm algorithm is verified by application to various physical regimes. 1 Introduction The coupling
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.
Control of the geometric phase and pseudo-spin dynamics on coupled Bose-Einstein condensates
E. I. Duzzioni; L. Sanz; S. S. Mizrahi; M. H. Y. Moussa
2006-12-26T23:59:59.000Z
We describe the behavior of two coupled Bose-Einstein condensates in time-dependent (TD) trap potentials and TD Rabi (or tunneling) frequency, using the two-mode approach. Starting from Bloch states, we succeed to get analytical solutions for the TD Schroedinger equation and present a detailed analysis of the relative and geometric phases acquired by the wave function of the condensates, as well as their population imbalance. We also establish a connection between the geometric phases and constants of motion which characterize the dynamic of the system. Besides analyzing the affects of temporality on condensates that differs by hyperfine degrees of freedom (internal Josephson effect), we also do present a brief discussion of a one specie condensate in a double-well potential (external Josephson effect).
Probabilistic quantum phase-space simulation of Bell violations and their dynamical evolution
Laura Rosales-Zárate; Bogdan Opanchuk; Peter D. Drummond; Margaret D. Reid
2014-07-09T23:59:59.000Z
Quantum simulations of Bell inequality violations are numerically obtained using probabilistic phase space methods, namely the positive P-representation. In this approach the moments of quantum observables are evaluated as moments of variables that have values outside the normal eigenvalue range. There is thus a parallel with quantum weak measurements and weak values. Nevertheless, the representation is exactly equivalent to quantum mechanics. A number of states violating Bell inequalities are sampled, demonstrating that these quantum paradoxes can be treated with probabilistic methods. We treat quantum dynamics by simulating the time evolution of the Bell state formed via parametric down-conversion, and discuss multi-mode generalizations.
Dynamic density field measurements of an explosively driven ????? phase transition in iron
Hull, L. M.; Gray, G. T.; Warthen, B. J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)
2014-07-28T23:59:59.000Z
We provide a unique set of observations of the behavior of the ??? phase transition under a complex axially symmetric loading path created by sweeping a detonation wave along the end surface of a cylindrical sample. The primary data sets are the measured mass density distributions acquired at 5 independent times during the sweep of the detonation along the surface. Shocked regions and boundaries are measured, as well as regions and boundaries of elevated density (presumed to be the ??phase iron). The formation and dynamics of these regions were captured and are available for comparisons to material descriptions. We also applied 16 Photon Doppler Velocimetry probes to capture the free surface velocity along a discrete set of radially distributed points in order to compare and correlate the density measurements with previous shock wave studies. The velocimetry data are in nearly exact agreement with previous shock wave studies of the ??? phase transition, the density distributions, while generally in agreement with expectations evolved from the shock wave studies, show that the epsilon phase is generated in regions of high shear stress but at hydrostatic stresses below the typically quoted 13?GPa value. The density field measurements are particularly useful for observing the effects of the forward and reverse transformation kinetics, as well as the reverse transformation hysteresis.
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.
Two liquid states of matter: A new dynamic line on a phase diagram
V. V. Brazhkin; Yu. D. Fomin; A. G. Lyapin; V. N. Ryzhov; Kostya Trachenko
2011-07-29T23:59:59.000Z
It is generally agreed that the supercritical region of a liquid consists of one single state (supercritical fluid). On the other hand, we show here that liquids in this region exist in two qualitatively different states: "rigid" and "non-rigid" liquid. Rigid to non-rigid transition corresponds to the condition {\\tau} ~ {\\tau}0, where {\\tau}is liquid relaxation time and {\\tau}0 is the minimal period of transverse quasi-harmonic waves. This condition defines a new dynamic line on the phase diagram, and corresponds to the loss of shear stiffness of a liquid at all available frequencies, and consequently to the qualitative change of many important liquid properties. We analyze the dynamic line theoretically as well as in real and model liquids, and show that the transition corresponds to the disappearance of high-frequency sound, qualitative changes of diffusion and viscous flow, increase of particle thermal speed to half of the speed of sound and reduction of the constant volume specific heat to 2kB per particle. In contrast to the Widom line that exists near the critical point only, the new dynamic line is universal: it separates two liquid states at arbitrarily high pressure and temperature, and exists in systems where liquid - gas transition and the critical point are absent overall.
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.
Two liquid states of matter: A new dynamic line on a phase diagram
Brazhkin, V V; Lyapin, A G; Ryzhov, V N; Trachenko, Kostya
2011-01-01T23:59:59.000Z
It is generally agreed that the supercritical region of a liquid consists of one single state (supercritical fluid). On the other hand, we show here that liquids in this region exist in two qualitatively different states: "rigid" and "non-rigid" liquid. Rigid to non-rigid transition corresponds to the condition {\\tau} ~ {\\tau}0, where {\\tau} is liquid relaxation time and {\\tau}0 is the minimal period of transverse waves. This condition defines a new dynamic line on the phase diagram, and corresponds to the loss of shear stiffness of a liquid at all available frequencies, and consequently to the qualitative change of many important liquid properties. We analyze the dynamic line theoretically as well as in real and model liquids, and show that the transition corresponds to the disappearance of high-frequency sound, qualitative changes of diffusion and viscous flow increase of particle thermal speed to half of the speed of sound and reduction of the constant volume specific heat to 2kB per particle. In contrast ...
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.
Fayer, Michael D.
-4-pentylbiphenyl (5CB), with the CN stretch initially used as the vibrational probe. Although the CN-thiocyanobiphenyl (5SCB) was synthesized and studied as a dilute solute in 5CB. The CN stretch of 5SCB has of fast structural dynamics in the isotropic phase of 5CB. It is shown that the 5SCB probe reports
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
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.
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.
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...
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
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
Rainer Jakob
2000-10-16T23:59:59.000Z
We present the handbag contribution to Wide Angle Compton Scattering (WACS) at moderately large momentum transfer obtained with a proton distribution amplitude close to the asymptotic form. In comparison it is found to be significantly larger than results from the hard scattering (pQCD) approach.
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.
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 ...
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.
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...
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}).
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
STELLAR ORBITAL STUDIES IN NORMAL SPIRAL GALAXIES. I. RESTRICTIONS TO THE PITCH ANGLE
Perez-Villegas, A.; Pichardo, B.; Moreno, E., E-mail: barbara@astro.unam.mx [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, A.P. 70-264, 04510 Mexico DF (Mexico)
2013-08-01T23:59:59.000Z
We built a family of non-axisymmetric potential models for normal non-barred or weakly barred spiral galaxies as defined in the simplest classification of galaxies: the Hubble sequence. For this purpose, a three-dimensional self-gravitating model for the spiral arm PERLAS is superimposed on the galactic axisymmetric potentials. We analyze the stellar dynamics varying only the pitch angle of the spiral arms, from 4 Degree-Sign to 40 Degree-Sign for an Sa galaxy, from 8 Degree-Sign to 45 Degree-Sign for an Sb galaxy, and from 10 Degree-Sign to 60 Degree-Sign for an Sc galaxy. Self-consistency is indirectly tested through periodic orbital analysis and through density response studies for each morphological type. Based on ordered behavior, periodic orbit studies show that, for pitch angles up to approximately 15 Degree-Sign , 18 Degree-Sign , and 20 Degree-Sign for Sa, Sb, and Sc galaxies, respectively, the density response supports the spiral arms' potential, a requisite for the existence of a long-lasting large-scale spiral structure. Beyond those limits, the density response tends to ''avoid'' the potential imposed by maintaining lower pitch angles in the density response; in that case, the spiral arms may be explained as transient features rather than long-lasting large-scale structures. In a second limit, from a phase-space orbital study based on chaotic behavior, we found that for pitch angles larger than {approx}30 Degree-Sign , {approx}40 Degree-Sign , and {approx}50 Degree-Sign for Sa, Sb, and Sc galaxies, respectively, chaotic orbits dominate the all phase-space prograde region that surrounds the periodic orbits sculpting the spiral arms and even destroying them. This result seems to be in good agreement with observations of pitch angles in typical isolated normal spiral galaxies.
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 ...
Phase-Diffusion Dynamics in Weakly Coupled Bose-Einstein Condensates Erez Boukobza,1
Vardi, Amichay
-matter models. In addition to offering remark- able controllability, they open the way for exploring non states j=2; 'i ¼ 1 ffiffiffiffiffiffiffiffiffiffiffi N!2N p ðay 1 þ ei'ay 2 ÞNjvacuumi: (2) In phase
In-situ Monitoring of Dynamic Phenomena during Solidification and Phase Transformation Processing
Clarke, Amy J. [Los Alamos National Laboratory; Cooley, Jason C. [Los Alamos National Laboratory; Morris, Christopher [Los Alamos National Laboratory; Merrill, Frank E. [Los Alamos National Laboratory; Hollander, Brian J. [Los Alamos National Laboratory; Mariam, Fesseha G. [Los Alamos National Laboratory; Patterson, Brian M. [Los Alamos National Laboratory; Imhoff, Seth D. [Los Alamos National Laboratory; Lee, Wah Keat [Brookhaven National Lab; Fezzaa, Kamel [Argonne National Lab; Deriy, Alex [Argonne NationalLbaoratory; Tucker, Tim J. [Los Alamos National Laboratory; Clarke, Kester D. [Los Alamos National Laboratory; Field, Robert D. [Los Alamos National Laboratory; Thoma, Dan J. [Los Alamos National Laboratory; Teter, David F. [Los Alamos National Laboratory; Beard, Timothy V. [Los Alamos National Laboratory; Hudson, Richard W. [Los Alamos National Laboratory; Freibert, Franz J. [Los Alamos National Laboratory; Korzekwa, Deniece R. [Los Alamos National Laboratory; Farrow, Adam M. [Los Alamos National Laboratory; Cross, Carl E. [Los Alamos National Laboratory; Mihaila, Bogdan [Los Alamos National Laboratory; Lookman, Turab [Los Alamos National Laboratory; Hunter, Abigail [Los Alamos National Laboratory; Choudhury, Samrat [Los Alamos National Laboratory; Karma, Alain [Northeastern University; Ott, Thomas J. Jr. [Los Alamos National Laboratory; Barker, Martha R. [Los Alamos National Laboratory; O'Neill, Finian [Former MST-6 Summer Student; Hill, Joshua [Former MST-6 Summer Student; Emigh, Megan G. [Los Alamos National Laboratory
2012-07-30T23:59:59.000Z
The purpose of this project is to: (1) Directly observe phase transformations and microstructure evolution using proton (and synchrotron x-ray) radiography and tomography; (2) Constrain phase-field models for microstructure evolution; (3) Experimentally control microstructure evolution during processing to enable co-design; and (4) Advance toward the MaRIE vision. Understand microstructure evolution and chemical segregation during solidification {yields} solid-state transformations in Pu-Ga.
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.
Baird, J.A.; Apostal, M.C.; Rotelli, R.L. Jr.; Tinianow, M.A.; Wormley, D.N.
1984-06-01T23:59:59.000Z
The Theoretical Description for the GEODYN interactive finite-element computer program is presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit-Bit Sub arising from the intermittent contact of the bit with the downhole rock formations. The program accommodates nonlinear, time-dependent, loading and boundary conditions.
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.
Phase space dynamics of triaxial collapse: II. Universal evolution of axis ratios
Nadkarni-Ghosh, Sharvari
2015-01-01T23:59:59.000Z
In paper I of this series, we examined triaxial collapse in terms of the dynamics of eigenvalues of three important tensors: the Hessian of the gravitational potential, the tensor of velocity derivatives and the deformation tensor. The first paper focussed on the joint gravity-velocity dynamics and here we focus on the deformation tensor, which is directly related to the axes' evolution. We examine the evolution of the minor to major and intermediate to major axes ratios ($s$ and $q$) and the triaxiality parameter $T$ as function of mass scale and redshift. We find that the ellipticity and prolateness increase with decreasing mass scale and decreasing redshift. These trends, while in agreement with previous analytic studies, contradict numerical simulations. Nevertheless, we find that a suitable transformation of $s$, motivated by the scaling used in recent analysis of the Millennium XXL simulations by Bonamigo {\\it et al} (2014), has a universal log-normal distribution function that matches their numerical r...
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.
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.
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.
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...
Cajahuaringa, Samuel; Koning, Maurice de, E-mail: dekoning@ifi.unicamp.br; Antonelli, Alex, E-mail: aantone@ifi.unicamp.br [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-859 Campinas, São Paulo (Brazil)] [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-859 Campinas, São Paulo (Brazil)
2013-12-14T23:59:59.000Z
Using molecular dynamics simulations we analyze the dynamics of two atomic liquids that display a liquid-liquid phase transition (LLPT): Si described by the Stillinger-Weber potential and Ga as modeled by the modified embedded-atom model. In particular, our objective is to investigate the extent to which the presence of a dip in the self-intermediate scattering function is a manifestation of an excess of vibrational states at low frequencies and may be associated with a fragile-to-strong transition (FTST) across the LLPT, as suggested recently. Our results suggest a somewhat different picture. First, in the case of Ga we observe the appearance of an excess of vibrational states at low frequencies, even in the absence of the appearance of a dip in the self-intermediate scattering function across the LLPT. Second, studying the behavior of the shear viscosities traversing the LLPTs we find that both substances are fragile in character above and below their respective LLPT temperatures. Instead of a FTST in an absolute sense these findings are more in line with a view in which the LLPTs are accompanied by a transition from a more fragile to a less fragile liquid. Furthermore, we do not find this transition to correlate with the presence of a dip in the intermediate scattering function.
Jia, Kun [The State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049 (China); Mei, Deqing, E-mail: meidq-127@zju.edu.cn; Meng, Jianxin; Yang, Keji [The State Key Laboratory of Fluid Power Transmission and Control, Department of Mechanical Engineering, Zhejiang University, Hangzhou 310027 (China)
2014-10-28T23:59:59.000Z
Ultrasonic manipulation has become an attractive method for surface-sensitive objects in micro-technology. Related phenomena, such as radiation force, multiple scattering, and acoustic streaming, have been widely studied. However, in current studies, the behavior of micro-particles in potential force fields is always analyzed in a quasi-static manner. We developed a dynamic model of a dilute micro-particle in the commonly used two-dimensional ultrasonic manipulation system to provide a systemic and quantitative analysis of the transient properties of particle movement. In this model, the acoustic streaming and hydrodynamic forces, omitted in previous work, were both considered. The trajectory of a spherical silica particle with different initial conditions was derived by numerically solving the established nonlinear differential integral equation system, which was then validated experimentally. The envelope of the experimental data on the x-axis showed good agreement with the theoretical calculation, and the greater influence on the y-axis of the deviation between the actual sound field and the ideal distribution employed in our dynamic model could account for the differences in displacement in that direction. Finally, the influence of particle size on its movement and the effect of acoustic streaming on calculating the hydrodynamic forces for an isolated particle with motion relative to the fluid were analyzed theoretically. It was found that the ultrasonic manipulation system will translate from an under-damped system to an over-damped system with a decrease in particle size and the micro-scale acoustic streaming velocity was negligible when calculating the hydrodynamic forces on the particle in the ultrasonic manipulation system.
Thermal analysis of adsorptive natural gas storages during dynamic charge phase at room temperature
Ridha, Firas N.; Yunus, Rosli M.; Rashid, Mohd. [Department of Chemical Engineering, University of Technology Malaysia, 81310 UTM, Skudai, Johor (Malaysia); Ismail, Ahmad F. [Department of Gas Engineering, University of Technology Malaysia, 81310 UTM, Skudai, Johor (Malaysia)
2007-10-15T23:59:59.000Z
The thermal behavior of an adsorptive natural gas (ANG) vessel pressurized continuously with light hydrocarbon gases and their mixture at 27 C was analyzed using two different activated carbons. Activated carbon AC-L showed better isothermal storage capacity than AC-D due to its sufficient porous structure. However, higher adsorption capacity claimed more extreme thermal fluctuation represented by a temperature rise of 99.2 C at the center region of the bed charged continuously with methane at 1 L min{sup -1} up to pressure of 4 MPa, corresponding to 82.5 C in AC-D bed. Higher charge rate of 5 L min{sup -1} claimed severer thermal fluctuation of 116 C in AC-L/methane system calling for a serious reduction of 26.9% in the dynamic storage capacity with respect to the isothermal storage capacity. This reduction brought the storage system to a working pressure of about 2.5 MPa rather than the desired working pressure of {proportional_to}4 MPa (about 40% reduction in storage pressure). The severest temperature rise was at the center region caused by bed poor thermal conductivity leading to limited heat transfer. High ethane and propane portions in natural gas may contribute to the thermal fluctuation of the storage system as their heats of adsorption are higher than that for methane. (author)
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
Angling chromium to let oxygen through | EMSL
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Angling chromium to let oxygen through Angling chromium to let oxygen through Released: September 10, 2014 New semiconducting material works at lower temperatures Scanning...
Gherib, Rami; Izmaylov, Artur F
2015-01-01T23:59:59.000Z
Adequate simulation of non-adiabatic dynamics through conical intersection requires account for a non-trivial geometric phase (GP) emerging in electronic and nuclear wave-functions in the adiabatic representation. Popular mixed quantum-classical (MQC) methods, surface hopping and Ehrenfest, do not carry a nuclear wave-function to be able to incorporate the GP into nuclear dynamics. Surprisingly, the MQC methods reproduce ultra-fast interstate crossing dynamics generated with the exact quantum propagation so well as if they contained information about the GP. Using two-dimensional linear vibronic coupling models we unravel how the MQC methods can effectively mimic the most significant dynamical GP effects: 1) compensation for repulsive diagonal second order non-adiabatic couplings and 2) transfer enhancement for a fully cylindrically symmetric component of a nuclear distribution.
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.
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
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
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...
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7111AWell: Gas productionDynamic , and Static ,
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...
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
Angle-resolved effective potentials for disk-shaped molecules
Thomas Heinemann; Karol Palczynski; Joachim Dzubiella; Sabine H. L. Klapp
2014-10-22T23:59:59.000Z
We present an approach for calculating coarse-grained angle-resolved effective pair potentials for uniaxial molecules. For integrating out the intramolecular degrees of freedom we apply umbrella sampling and steered dynamics techniques in atomistically-resolved molecular dynamics (MD) computer simulations. Throughout this study we focus on disk-like molecules such as coronene. To develop the methods we focus on integrating out the van-der-Waals and intramolecular interactions, while electrostatic charge contributions are neglected. The resulting coarse-grained pair potential reveals a strong temperature and angle dependence. In the next step we fit the numerical data with various Gay-Berne-like potentials to be used in more efficient simulations on larger scales. The quality of the resulting coarse-grained results is evaluated by comparing their pair and many-body structure as well as some thermodynamic quantities self-consistently to the outcome of atomistic MD simulations of many particle systems. We find that angle-resolved potentials are essential not only to accurately describe crystal structures but also for fluid systems where simple isotropic potentials start to fail already for low to moderate packing fractions. Further, in describing these states it is crucial to take into account the pronounced temperature dependence arising in selected pair configurations due to bending fluctuations.
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.
Sitnov, Mikhail I.
, this exponent relates input and output parameters of the magnetosphere. Using an analogy to the dynamical Ising model in the mean-field approximation, we show the connection between the data-derived exponent in the flow of the plasma coming from the Sun solar wind . Part of the solar wind energy penetrates
. It is then a potential method for reducing energy consumption in passively designed buildings. This tendency is confirmed, the use of Phase Change Materials (PCM) allows the storage/release of energy from solar radiation and internal loads. The application of such materials for lightweight construction (e.g., a wood house) makes
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.
Eldredge, B.D; Rasmussen, B.P.; Alleyne, A.
, MEASUREMENT, AND CON- ROL. Manuscript received June 8, 2006; final manuscript received May 22, 2008; ublished online September 24, 2008. Assoc. Editor: Huei Peng. ournal of Dynamic Systems, Measurement, and Control NOVEMBER 2008, Vol. 130 / 061003-1Brian D.... Eldredge University of Illinois at Urbana-Champaign, 158 MEB, MC-244, 1206 West Green Street, Urbana, IL 61801 e-mail: brian.eldredge@gmail.com Bryan P. Rasmussen Texas A&M University, 3123 TAMU, College Station, TX 77843-3123 e-mail: brasmussen...
Stránský, Pavel [Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovi?kách 2, 18000 Prague (Czech Republic); Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, 04510, México, D.F. (Mexico); Macek, Michal [Racah Institute of Physics, The Hebrew University, 91904 Jerusalem (Israel); Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovi?kách 2, 18000 Prague (Czech Republic); Cejnar, Pavel, E-mail: pavel.cejnar@mff.cuni.cz [Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovi?kách 2, 18000 Prague (Czech Republic)
2014-06-15T23:59:59.000Z
Quantum systems with a finite number of freedom degrees f develop robust singularities in the energy spectrum of excited states as the system’s size increases to infinity. We analyze the general form of these singularities for low f, particularly f=2, clarifying the relation to classical stationary points of the corresponding potential. Signatures in the smoothed energy dependence of the quantum state density and in the flow of energy levels with an arbitrary control parameter are described along with the relevant thermodynamical consequences. The general analysis is illustrated with specific examples of excited-state singularities accompanying the first-order quantum phase transition. -- Highlights: •ESQPTs found in infinite-size limit of systems with low numbers of freedom degrees f. •ESQPTs related to non-analytical evolutions of classical phase–space properties. •ESQPT signatures analyzed for general f, particularly f=2, extending known case f=1. •ESQPT signatures identified in smoothened density and flow of energy spectrum. •ESQPTs shown to induce a new type of thermodynamic anomalies.
Surface tension of multi-phase flow with multiple junctions governed by the variational principle
Shigeki Matsutani; Kota Nakano; Katsuhiko Shinjo
2011-08-02T23:59:59.000Z
We explore a computational model of an incompressible fluid with a multi-phase field in three-dimensional Euclidean space. By investigating an incompressible fluid with a two-phase field geometrically, we reformulate the expression of the surface tension for the two-phase field found by Lafaurie, Nardone, Scardovelli, Zaleski and Zanetti (J. Comp. Phys. \\vol{113} \\yr{1994} \\pages{134-147}) as a variational problem related to an infinite dimensional Lie group, the volume-preserving diffeomorphism. The variational principle to the action integral with the surface energy reproduces their Euler equation of the two-phase field with the surface tension. Since the surface energy of multiple interfaces even with singularities is not difficult to be evaluated in general and the variational formulation works for every action integral, the new formulation enables us to extend their expression to that of a multi-phase ($N$-phase, $N\\ge2$) flow and to obtain a novel Euler equation with the surface tension of the multi-phase field. The obtained Euler equation governs the equation of motion of the multi-phase field with different surface tension coefficients without any difficulties for the singularities at multiple junctions. In other words, we unify the theory of multi-phase fields which express low dimensional interface geometry and the theory of the incompressible fluid dynamics on the infinite dimensional geometry as a variational problem. We apply the equation to the contact angle problems at triple junctions. We computed the fluid dynamics for a two-phase field with a wall numerically and show the numerical computational results that for given surface tension coefficients, the contact angles are generated by the surface tension as results of balances of the kinematic energy and the surface energy.
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
of the influence of backrest inclination on lumbar lordosis have shown that as trunk-thigh angle increases from the vertical, lumbar lordosis likewise increases towards a more neutral posture (Bridger er al 1989b, Keegan 1953). Keegan reported that the neutral...'il, ", ' " r 20. 32 35, 56 Knee Separation (cmi Figure 5 Lordotic angles for females with backrest at 90-deg Lordotic Angles for Females with Seat Back Angle of 105 Degrees p =0. 881 5. 08 e0 3'r 35. 56 Knoe S. 'prwation (cm} Lordotic Angles for Fcmalcs...
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 $\\phi_S\\leq 0.2$.
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.
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.
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
Two wide-angle imaging neutral-atom spectrometers
McComas, D.J.
1997-12-31T23:59:59.000Z
The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission provides a new capability for stereoscopically imaging the magnetosphere. By imaging the charge exchange neutral atoms over a broad energy range (1 < E , {approximately} 100 keV) using two identical instruments on two widely-spaced high-altitude, high-inclination spacecraft, TWINS will enable the 3-dimensional visualization and the resolution of large scale structures and dynamics within the magnetosphere for the first time. These observations will provide a leap ahead in the understanding of the global aspects of the terrestrial magnetosphere and directly address a number of critical issues in the ``Sun-Earth Connections`` science theme of the NASA Office of Space Science.
IR OPTICS MEASUREMENT WITH LINEAR COUPLING'S ACTION-ANGLE PARAMETERIZATION.
LUO, Y.; BAI, M.; PILAT, R.; SATOGATA, T.; TRBOJEVIC, D.
2005-05-16T23:59:59.000Z
A parameterization of linear coupling in action-angle coordinates is convenient for analytical calculations and interpretation of turn-by-turn (TBT) beam position monitor (BPM) data. We demonstrate how to use this parameterization to extract the twiss and coupling parameters in interaction regions (IRs), using BPMs on each side of the long IR drift region. The example of TBT BPM analysis was acquired at the Relativistic Heavy Ion Collider (RHIC), using an AC dipole to excite a single eigenmode. Besides the full treatment, a fast estimate of beta*, the beta function at the interaction point (IP), is provided, along with the phase advance between these BPMs. We also calculate and measure the waist of the beta function and the local optics.
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 .
Dabdub, Donald
condensed products of gas phase oxidation, the present model can be viewed as the most detailed SOA of the semivolatile or nonvolatile products of VOC oxidation between the gas and particle phases. Chem- ical analysis of the SOA identifies many products that condense, thereby allowing formulation of gas phase path- ways
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
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 ...
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.
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.
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our Instagram Secretary Moniz9Morgan ManagingW.tepidumAngle X-ray Scattering
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.
Aggregation, Coarsening, and Phase Transformation in ZnSNanoparticles...
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Coarsening, and Phase Transformation in ZnS NanoparticlesStudied by Molecular Dynamics Simulations. Aggregation, Coarsening, and Phase Transformation in ZnS...
angle diffractometer sans: Topics by E-print Network
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14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 SANS -Small Angle Neutron Scattering Tcnica de difrao Chemistry Websites Summary: SANS - Small Angle Neutron...
angle neutron diffractometer: Topics by E-print Network
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steel Low alloy ferritic steel Alloy 52 L0 L d0 d Bandara, Arosha 6 SANS -Small Angle Neutron Scattering Tcnica de difrao Chemistry Websites Summary: SANS - Small Angle Neutron...
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.
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
SECULAR ORBITAL DYNAMICS OF HIERARCHICAL TWO-PLANET SYSTEMS
Veras, Dimitri; Ford, Eric B., E-mail: veras@astro.ufl.ed [Astronomy Department, University of Florida, 211 Bryant Space Sciences Center, Gainesville, FL 32111 (United States)
2010-06-01T23:59:59.000Z
The discovery of multi-planet extrasolar systems has kindled interest in using their orbital evolution as a probe of planet formation. Accurate descriptions of planetary orbits identify systems that could hide additional planets or be in a special dynamical state, and inform targeted follow-up observations. We combine published radial velocity data with Markov Chain Monte Carlo analyses in order to obtain an ensemble of masses, semimajor axes, eccentricities, and orbital angles for each of the five dynamically active multi-planet systems: HD 11964, HD 38529, HD 108874, HD 168443, and HD 190360. We dynamically evolve these systems using 52,000 long-term N-body integrations that sample the full range of possible line-of-sight and relative inclinations, and we report on the system stability, secular evolution, and the extent of the resonant interactions. We find that planetary orbits in hierarchical systems exhibit complex dynamics and can become highly eccentric and maybe significantly inclined. Additionally, we incorporate the effects of general relativity in the long-term simulations and demonstrate that it can qualitatively affect the dynamics of some systems with high relative inclinations. The simulations quantify the likelihood of different dynamical regimes for each system and highlight the dangers of restricting simulation phase space to a single set of initial conditions or coplanar orbits.
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.
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...
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 ...
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
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.
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...
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.
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.
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...
Understanding reservoir mechanisms using phase and component streamline tracing
Kumar, Sarwesh
2009-05-15T23:59:59.000Z
some important signatures of reservoir dynamics, such as dominant phase in flow, appearance and disappearance of phases (e.g. gas), and flow of components like CO2. In the work being presented, we demonstrate the benefits of visualizing phase...
Basrak, Z.; Zoric, M. [Ruder Boskovic Institute, Zagreb (Croatia); Eudes, P.; Sebille, F. [Subatech, EMN-IN2P3/CNRS-Universite de Nantes, Nantes (France)
2009-08-26T23:59:59.000Z
With a semi-classical transport model studied is the impact of the in-medium NN cross section modifications on the early energy transformation, dynamical emission and quasiprojectile properties of the Ar+Ni and Ni+Ni reactions at 52, 74 and 95(90) A MeV.
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
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.
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.
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
angle light scattering: Topics by E-print Network
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Biological tissues tend Kim, Arnold D. 11 Static light scattering and small-angle neutron scattering study on aggregated recombinant gelatin in aqueous solution University...
angle scattering studies: Topics by E-print Network
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report gives selected examples illustrating the use of specific techni- cal 2 Small-Angle Neutron Scattering Studies of Charged Carboxyl-Terminated Dendrimers in Solutions...
angling commercial: Topics by E-print Network
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chronic open angle glaucoma by UK community optometrists. (Unpublished Doctoral thesis, City University London) City Research Online Original citation: Myint, Joy (2013). A study...
Local Uniqueness for the Fixed Energy Fixed Angle Inverse Problem ...
Abstract. We prove local uniqueness for the inverse problem in obstacle scattering at a fixed energy and fixed incident angle. We consider the inverse problem of ...
angle changing device: Topics by E-print Network
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bend angle Physics Websites Summary: mercury water flow through a bend pipe into the air environment Medium Reynolds Number Inner DiameterSimulation for pipes with changing bend...
The new small-angle diffractometer SAND at IPNS
Crawford, R.K.; Thiyagarajan, P.; Epperson, J.E.; Trouw, F.; Kleb, R.; Wozniak, D.; Leach, D.
1995-12-31T23:59:59.000Z
A new small-angle neutron diffractometer SAND is undergoing commissioning at IPNS pulsed source. This paper provides details of the design and expected performance of this instrument.
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.
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.
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.
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
Effect of Mesophase Order on the Dynamics of Side Group Liquid Crystalline Polymers
Auad, M.L.; Kempe, M.D.; Kornfield, J.A.; Rendon, S.; Burghardt, W.R.; Yoon, K. (CIT); (NWU); (Dankook)
2010-07-13T23:59:59.000Z
Rheology and X-ray scattering were employed to probe the viscoelastic properties and structural transitions of model cyano-biphenyl-based side-group liquid-crystalline polymers (SGLCPs) with molecular weights ranging from 91 to 1900 kg/mol. Temperature-dependent rheological data show a rapid change in dynamics over a small temperature range. Small-angle X-ray scattering reveals these changes to be associated with an isotropic to smectic transition with an appreciable biphasic region. The presence of a biphasic region is attributed to inhomogeneity in chain structure resulting from incomplete attachment of mesogens to every monomeric unit in the SGLCP polymer. While isotropic and smectic phase data may be separately time-temperature shifted to create master curves for the individual phases, we argue against attempts to achieve superposition between the two phases in the high-frequency regime, since smectic ordering may not simply slow the dynamics but also increase the modulus of the sample. Molecular weight has a strong influence on rheology in the isotropic phase, where an entanglement plateau emerges; however, the smectic-phase rheology is dominated by the layer structure and is fairly insensitive to molecular weight.
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.
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.
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.
Measurements of the CKM Angle beta
Rainer Bartoldus
2005-11-04T23:59:59.000Z
In this article I report on new and updated measurements of the CP-violating parameter beta (phi_1), which is related to the phase of the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrix of the electroweak interaction. Over the past few years, beta has become the most precisely known parameter of the CKM unitarity triangle that governs the B system. The results presented here were produced by the two B factories, BaBar and Belle, based on their most recent datasets of over 600 million BB events combined. The new world average for sin(2beta), measured in the theoretically and experimentally cleanest charmonium modes, such as B -> J/psi K0s, is sin(2beta) = 0.685 +- 0.032. In addition to these tree-level dominated decays, independent measurements of sin(2beta) are obtained from gluonic b --> s penguin decays, including B --> phi K0s, B --> eta' K0s and others. There are hints, albeit somewhat weaker than earlier this year, that these measurements tend to come out low compared to the charmonium average, giving rise to the tantalizing possibility that New Physics amplitudes could be contributing to the corresponding loop diagrams. Clearly, more data from both experiments are needed to elucidate these intriguing differences.
Adsorption dynamics and angular dependency of contaminants on Ru mirror surfaces
Harilal, S. S.
Adsorption dynamics and angular dependency of contaminants on Ru mirror surfaces M. Catalfano,a) A of the adsorption dynamics and of the emission angle (h from the target surface) dependency are still scarce
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.
angle diffraction studies: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
A. 3 DMSO-Induced Dehydration of DPPC Membranes Studied by X-ray Diffraction, Small-Angle Neutron Scattering, and Calorimetry Condensed Matter (arXiv) Summary: The influence of...
Bond Angle Torsion http://www.nobelprize.org/
Fukai, Tomoki
MARBLE-K 20141024 1 #12;2 MARBLE MARBLE #12;MD Bond Angle Torsion http) MARBLE-K PME CHARMM Force Field AMBER Force Field NMRSAXS molx XNMR #12;MARBLE
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.
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.
Ultrathin metal-semiconductor-metal resonator for angle invariant visible band transmission filters
Lee, Kyu-Tae; Seo, Sungyong; Yong Lee, Jae; Jay Guo, L., E-mail: guo@umich.edu [Department of Electrical Engineering and Computer Science, The University of Michigan, Ann Arbor, Michigan 48109 (United States)
2014-06-09T23:59:59.000Z
We present transmission visible wavelength filters based on strong interference behaviors in an ultrathin semiconductor material between two metal layers. The proposed devices were fabricated on 2?cm?×?2?cm glass substrate, and the transmission characteristics show good agreement with the design. Due to a significantly reduced light propagation phase change associated with the ultrathin semiconductor layer and the compensation in phase shift of light reflecting from the metal surface, the filters show an angle insensitive performance up to ±70°, thus, addressing one of the key challenges facing the previously reported photonic and plasmonic color filters. This principle, described in this paper, can have potential for diverse applications ranging from color display devices to the image sensors.
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
Alpha phase precipitation from phase-separated beta phase in...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Alpha phase precipitation from phase-separated beta phase in a model Ti-Mo-Al alloy studied by direct coupling of transmission Alpha phase precipitation from phase-separated beta...
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.
A two-phase method for selecting IMRT treatment beam angles ...
2011-09-08T23:59:59.000Z
Sep 8, 2011 ... to neighborhood search methods for beam orientation optimization for total marrow irradiation using imrt, European Journal of Operational.
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...
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.
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.
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.
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.
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.
Off-Angle Iris Correction using a Biological Model
Thompson, Joseph T [ORNL] [ORNL; Santos-Villalobos, Hector J [ORNL] [ORNL; Karakaya, Mahmut [ORNL] [ORNL; Barstow, Del R [ORNL] [ORNL; Bolme, David S [ORNL] [ORNL; Boehnen, Chris Bensing [ORNL] [ORNL
2013-01-01T23:59:59.000Z
This work implements an eye model to simulate corneal refraction effects. Using this model, ray tracing is performed to calculate transforms to remove refractive effects in off-angle iris images when reprojected to a frontal view. The correction process is used as a preprocessing step for off-angle iris images for input to a commercial matcher. With this method, a match score distribution mean improvement of 11.65% for 30 degree images, 44.94% for 40 degree images, and 146.1% improvement for 50 degree images is observed versus match score distributions with unmodi ed images.
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.
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.
Prediction of Leptonic CP Phase in $A_4$ symmetric model
Sin Kyu Kang; Morimitsu Tanimoto
2015-01-29T23:59:59.000Z
We consider minimal modifications to tribimaximal (TBM) mixing matrix which accommodate non-zero mixing angle $\\theta_{13}$ and CP violation. We derive four possible forms for the minimal modifications to TBM mixing in a model with $A_4$ flavor symmetry by incorporating symmetry breaking terms appropriately. We show how possible values of the Dirac-type CP phase $\\delta_D$ can be predicted with regards to two neutrino mixing angles in the standard parametrization of the neutrino mixing matrix. Carrying out numerical analysis based on the recent updated experimental results for neutrino mixing angles, we predict the values of the CP phase for all possible cases. We also confront our predictions of the CP phase with the updated fit.
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
angle neutron scattering: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
neutron scattering First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 SANS -Small Angle Neutron Scattering...
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
Measurements of the angle alpha (phi2) at B factories
G. Vasseur
2008-10-02T23:59:59.000Z
The measurements of the angle alpha (phi2) of the unitarity triangle at the B factories are reviewed. The value of alpha determined by combining the results obtained in the B to pi pi, B to rho pi, and B to rho rho modes by both the BABAR and Belle experiments is (87.5 +6.2 -5.3) degrees.
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
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.
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.
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
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.
Wu, Hongchen; Anders, Andre
2009-09-15T23:59:59.000Z
The deposition of films under normal and off-normal angle of incidence has been investigated to show the relevance of non-sticking of and self-sputtering by energetic ions, leading to the formation of neutral atoms. The flow of energetic ions was obtained using a filtered cathodic arc system in high vacuum and therefore the ion flux had a broad energy distribution of typically 50-100 eV per ion. The range of materials included Cu, Ag, Au, Ti, and Ni. Consistent with molecular dynamics simulations published in the literature, the experiments show, for all materials, that the combined effects of non-sticking and self-sputtering are very significant, especially for large off-normal angles. Modest heating and intentional introduction of oxygen background affect the results.
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.
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.
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.
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...
angles loa mutation: Topics by E-print Network
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growth of atmospheric eddy continuum is in dynamical equilibrium and is associated with Maximum Entropy Production. The model predicts universal (scale-free) inverse power law...
angle resolved thermal: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
spectroscopy ARPES groups have Lombardi, John R. 18 Molecular dynamics simulations of thermal conductivity of carbon nanotubes: Resolving the effects of computational parameters...
Radiation damage studies using small-angle neutron scattering
Albertini, G.; Rustichelli, F. [INFM, Ancona (Italy); Carsughi, F. [INFM, Ancona (Italy). Ist. di Scienze Fisiche; [KFA, Juelich (Germany). Inst. fuer Festkoerperforschung; Coppola, R. [ENEA-Casaccia, Roma (Italy); Stefanon, M. [ENEA, Bologna (Italy)
1996-12-31T23:59:59.000Z
This contribution reviews a number of small-angle neutron scattering (SANS) studies of irradiated metals and steels of relevance to fission and fusion technology. Information obtainable by SANS measurements is recalled with special reference to the determination of the size distribution function of the microstructural inhomogeneities. The selected examples concern studies of the main kinds of radiation defects: voids, precipitates, He-bubbles. Some recent results obtained on structural materials for the first-wall of fusion reactors are also presented.
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.
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.
angle magnetron sputtering: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
sputtering. Highly oriented, crack-free, stoichiometric polycrystalline rutile TiO2 thin film; RF magnetron sputtering; Phase transition; Deposition parameter effects 1....
H. Seto; M. Hishida; H. Nobutou; N. L. Yamada; M. Nagao; T. Takeda
2006-02-21T23:59:59.000Z
A swollen phase, in which the mean repeat distance of lipid bilayers is larger than the other phases, is found between the liquid-crystalline phase and the interdigitated gel phase in DPPC aqueous solution. Temperature, pressure and ethanol concentration dependences of the structure were investigated by small-angle neutron scattering, and a bending rigidity of lipid bilayers was by neutron spin echo. The nature of the swollen phase is similar to the anomalous swelling reported previously. However, the temperature dependence of the mean repeat distance and the bending rigidity of lipid bilayers are different. This phase could be a precursor to the interdigitated gel phase induced by pressure and/or adding ethanol.
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.
Stosic, Zoran V. [Framatome ANP GmbH, P.O. Box 3220, 91050 Erlangen (Germany); Stevanovic, Vladimir D. [University of Belgrade, Kraljice Marije 16, 11000 Belgrade, Serbia and Montenegro (Yugoslavia)
2002-07-01T23:59:59.000Z
Computational fluid dynamics for multiphase flows is an emerging field. Due to the complexity and divergence of multiphase thermal and hydraulic problems, further development of multiphase flow modelling, closure laws and numerical methods is needed in order to achieve the general purpose and optimised CFD (Computational Fluid Dynamics) methods, which will be applicable to the wide variety of multiphase flow problems. In the paper, an original approach to the various aspects of multiphase CFD modelling is presented. It is based on the multi-fluid modelling approach, development of necessary closure laws and derivation of appropriate numerical methods for efficient governing equations solution. Velocity and pressure fields are solved with the SIMPLE (Semi-Implicit Method for Pressure-Linked Equations) type pressure-corrector method developed for the multiphase flow conditions. For the solution of scalar parameters transport equations both implicit and explicit methods are presented. The implicit method is suitable for steady state, slow transients and problems without the sharp fronts propagation. Explicit method is developed in order to predict scalar parameters fronts propagation, as well as phase interface tracking problems. The challenge towards the multiphase flow solution on both the macro and micro level is presented in order to perform multiphase CFD simulations and analyses of multiphase flows in complex geometry of nuclear power plant components, such as nuclear fuel rod bundles thermal-hydraulics. Presented methodology and obtained CFD results comprise micro-scale phenomena of phases' separation, interface tracking, heated surfaces dry-out and critical heat flux occurrence, as well as macro-scale transport and distributions of phase volumes. (authors)
Elasticity of Twist-Bend Nematic Phases
Epifanio G. Virga
2014-04-12T23:59:59.000Z
The ground state of twist-bend nematic liquid crystals is a heliconical molecular arrangement in which the nematic director precesses uniformly about an axis, making a fixed angle with it. Both precession senses are allowed in the ground state of these phases. When one of the two \\emph{helicities} is prescribed, a single helical nematic phase emerges. A quadratic elastic theory is proposed here for each of these phases which features the same elastic constants as the classical theory of the nematic phase, requiring all of them to be positive. To describe the helix axis, it introduces an extra director field which becomes redundant for ordinary nematics. Putting together helical nematics with opposite helicities, we reconstruct a twist-bend nematic, for which the quadratic elastic energies of the two helical variants are combined in a non-convex energy.
Lü, C D; L\\"u, Cai-Dian; Xiao, Zhenjun
2002-01-01T23:59:59.000Z
In this paper, we study and try to find the constraint on the CKM angle $\\alpha$ from the experimental measurements of CP violation in $B_d^0 \\to \\pi^+ \\pi^-$ decay, as reported very recently by BaBar and Belle Collaborations. After considering uncertainties of the data and the ratio $r$ of penguin over tree amplitude, we found that: (a) strong constraint on both the CKM angle $\\alpha$ and the strong phase $\\delta$ can be obtained from the measured $\\spp$, $A_{\\pi\\pi}$: only the ranges of $86^\\circ \\leq \\alpha \\leq 148^\\circ$ and $31^\\circ \\leq \\delta \\leq 143^\\circ$ are still allowed by $1\\sigma$ of the averaged data; (b) For Belle's result alone, the limit on $\\alpha$ is $95^\\circ \\leq \\alpha \\leq 152^\\circ$. The angle $\\alpha$ larger than $90^\\circ$ is strongly preferred.
The Nonlocal Pancharatnam Phase in Two-Photon Interferometry
Poonam Mehta; Joseph Samuel; Supurna Sinha
2010-09-03T23:59:59.000Z
We propose a polarised intensity interferometry experiment, which measures the nonlocal Pancharatnam phase acquired by a pair of Hanbury Brown-Twiss photons. The setup involves two polarised thermal sources illuminating two polarised detectors. Varying the relative polarisation angle of the detectors introduces a two photon geometric phase. Local measurements at either detector do not reveal the effects of the phase, which is an optical analog of the multiparticle Aharonov-Bohm effect. The geometric phase sheds light on the three slit experiment and suggests ways of tuning entanglement.
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...
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.
Non-local geometric phase in two-photon interferometry
Anthony Martin; Olivier Alibart; Jean-Christoph Flesch; Joseph Samuel; Supurna Sinha; Sébastien Tanzilli; Anders Kastberg
2012-01-05T23:59:59.000Z
We report the experimental observation of the nonlocal geometric phase in Hanbury Brown-Twiss polarized intensity interferometry. The experiment involves two independent, polar- ized, incoherent sources, illuminating two polarized detectors. Varying the relative polarization angle between the detectors introduces a geometric phase equal to half the solid angle on the Poincar\\'e sphere traced out by a pair of single photons. Local measurements at either detector do not reveal the effect of the geometric phase, which appears only in the coincidence counts between the two detectors, showing a genuinely nonlocal effect. We show experimentally that coincidence rates of photon arrival times at separated detectors can be controlled by the two photon geometric phase. This effect can be used for manipulating and controlling photonic entanglement.
Phase Transition in Tensor Models
Delepouve, Thibault
2015-01-01T23:59:59.000Z
Generalizing matrix models, tensor models generate dynamical triangulations in any dimension and support a $1/N$ expansion. Using the intermediate field representation we explicitly rewrite a quartic tensor model as a field theory for a fluctuation field around a vacuum state corresponding to the resummation of the entire leading order in $1/N$ (a resummation of the melonic family). We then prove that the critical regime in which the continuum limit in the sense of dynamical triangulations is reached is precisely a phase transition in the field theory sense for the fluctuation field.
ALMA : Fourier phase analysis made possible
F. Levrier; E. Falgarone; F. Viallefond
2007-04-18T23:59:59.000Z
Fourier phases contain a vast amount of information about structure in direct space, that most statistical tools never tap into. We address ALMA's ability to detect and recover this information, using the probability distribution function (PDF) of phase increments, and the related concepts of phase entropy and phase structure quantity. We show that ALMA, with its high dynamical range, is definitely needed to achieve significant detection of phase structure, and that it will do so even in the presence of a fair amount of atmospheric phase noise. We also show that ALMA should be able to recover the actual "amount" of phase structure in the noise-free case, if multiple configurations are used.
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.
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.
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.
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.
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)
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.
Material loss angles from direct measurements of broadband thermal noise
Principe, Maria; Pierro, Vincenzo; DeSalvo, Riccardo; Taurasi, Ilaria; Villar, Akira E; Black, Eric D; Libbrecht, Kenneth G; Michel, Christophe; Morgado, Nazario; Pinard, Laurent
2015-01-01T23:59:59.000Z
We estimate the loss angles of the materials currently used in the highly reflective test-mass coatings of interferometric detectors of gravitational waves, namely Silica, Tantala, and Ti-dop ed Tantala, from direct measurement of coating thermal noise in an optical interferometer testbench, the Caltech TNI. We also present a simple predictive theory for the material properties of amorphous glassy oxide mixtures, which gives results in good agreement with our measurements on Ti-doped Tantala. Alternative measure ment methods and results are reviewed, and some critical issues are discussed.
Autoresonant Phase-Space Holes in Plasmas L. Friedland,1
Friedland, Lazar
, for the first time, analyzes dynamics of the whole excitation process from the initial fluid-type phase locking are formed and controlled in a plasma by adiabatic nonlinear phase locking (autoresonance) with a chirped phase locking (autoresonance) and subsequent exci- tation of a large amplitude wave controlled
Phase slips and dissipation of Alfvenic intermediate shocks and solitons
Laveder, D.; Passot, T.; Sulem, P. L. [Universite de Nice-Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, B.P. 4229, 06304 Nice Cedex 4 (France)
2012-09-15T23:59:59.000Z
The time evolution of a rotational discontinuity, characterized by a change of the magnetic-field direction by an angle {Delta}{theta} such that {pi}<|{Delta}{theta}|<2{pi} and no amplitude variation, is considered in the framework of asymptotic models that, through reductive perturbative expansions, isolate the dynamics of parallel or quasi-parallel Alfven waves. In the presence of viscous and Ohmic dissipation, and for a zero or sufficiently weak dispersion (originating from the Hall effect), an intermediate shock rapidly forms, steepens and undergoes reconnection through a quasi gradient collapse, leading to a reduction of |{Delta}{theta}| by an amount of 2{pi}, which can be viewed as the breaking of a topological constraint. Afterwards, as |{Delta}{theta}|<{pi}, the intermediate shock broadens and slowly dissipates. In the case of a phase jump |{Delta}{theta}|>3{pi}, which corresponds to a wave train limited on both sides by uniform fields, a sequence of such reconnection processes takes place. Differently, in the presence of a strong enough dispersion, the rotational discontinuity evolves, depending on the sign of {Delta}{theta}, to a dark or bright soliton displaying a 2{pi} phase variation. The latter is then eliminated, directly by reconnection in the case of a dark soliton, or through a more complex process involving a quasi amplitude collapse in that of a bright soliton. Afterwards, the resulting structure is progressively damped. For a prescribed initial rotational discontinuity, both quasi gradient and amplitude collapses lead to a sizeable energy decay that in the collisional regime is independent of the diffusion coefficient {eta} but requires a time scaling like 1/{eta}. In the non-collisional regime where dissipation originates from Landau resonance, the amount of dissipated energy during the event is independent of the plasma {beta}, but the process becomes slower for smaller {beta}.
In Situ 13C and 23Na Magic Angle Spinning NMR Investigation of...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
In Situ 13C and 23Na Magic Angle Spinning NMR Investigation of Supercritical CO2 Incorporation in Smectite-Natural Organic In Situ 13C and 23Na Magic Angle Spinning NMR...
Correlation of Oil-Water and Air-Water Contact Angles of Diverse...
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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...
angle hysteresis effects: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of 1 eV or less, increasing Wadley, Haydn 155 Dynamics and hysteresis in square lattice artificial spin-ice G. M. Wysin Physics Websites Summary: interactions can be satisfied...
A Large Sample Volume Magic Angle Spinning Nuclear Magnetic Resonance...
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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.
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.
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.
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.
UNIVERSITY of CALIFORNIA INVESTIGATION OF HOW ANGLE OF ATTACK AFFECTS ROTOR SPEED
Belanger, David P.
-pitch blades is tested in UCSC's wind tunnel. The turbine is used to test how varying the blade angle affects the turbine's rotational speed at different wind speeds. The data are used to determine how the blade angle 27 Appendix A Wind Turbine Data 29 Appendix B Converting Blade Pitch to Needle Angle 33 Appendix C
A new method for analyzing collimation angle of neutron Soller collimator
Jian-Bo Gao; Yun-Tao Liu; Dong-Feng Chen
2015-03-18T23:59:59.000Z
A new method for analyzing collimation angle of neutron Soller collimator is described. Gaussian distribution formula is used to define the angle distribution function of neutron source and neutron transmission function of Soller collimator. A relationship between FWHM of collimator rocking curve and collimation angle is derived.
A new method for analyzing collimation angle of neutron Soller collimator
Gao, Jian-Bo; Chen, Dong-Feng
2015-01-01T23:59:59.000Z
A new method for analyzing collimation angle of neutron Soller collimator is described. Gaussian distribution formula is used to define the angle distribution function of neutron source and neutron transmission function of Soller collimator. A relationship between FWHM of collimator rocking curve and collimation angle is derived.
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
Sanchez, Juan A; Nathues, Andreas; Cloutis, Edward A; Mann, Paul; Hiesinger, Harald
2012-01-01T23:59:59.000Z
Phase reddening is an effect that produces an increase of the spectral slope and variations in the strength of the absorption bands as the phase angle increases. In order to understand its effect on spectroscopic observations of asteroids, we have analyzed the visible and near-infrared spectra (0.45-2.5 \\mu m) of 12 near-Earth asteroids observed at different phase angles. All these asteroids are classified as either S-complex or Q-type asteroids. In addition, we have acquired laboratory spectra of three different types of ordinary chondrites at phase angles ranging from 13\\degree to 120\\degree. We have found that both asteroid and meteorite spectra show an increase in band depths with increasing phase angle. The spectral slope of the ordinary chondrites spectra shows a significant increase with increasing phase angle for g > 30\\degree. Variations in band centers and band area ratio (BAR) values were also found, however they seems to have no significant impact on the mineralogical analysis. Our study showed th...
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.
Journal of Biomedical Optics 16(1), 011005 (January 2011) Video-rate tomographic phase microscopy
Fang-Yen, Christopher
distributions in biological sam- ples can be used to quantify local nonaqueous density,1 image cell fluctuations the information from a series of angle-dependent interferometric phase images. In the original device, the frame rate was limited to 0.1 frames per second (fps) by the technique used to acquire phase images
Geometric phase in Stückelberg interferometry
Lih-King Lim; Jean-Noël Fuchs; Gilles Montambaux
2014-12-18T23:59:59.000Z
We study the time evolution of a two-dimensional quantum particle exhibiting an energy spectrum, made of two bands, with two Dirac cones, as e.g. in the band structure of a honeycomb lattice. A force is applied such that the particle experiences two Landau-Zener transitions in succession. The adiabatic evolution between the two transitions leads to St\\"uckelberg interferences, due to two possible trajectories in energy space. In addition to well-known dynamical and Stokes phases, the interference pattern reveals a geometric phase which depends on the chirality (winding number) and the mass sign associated to each Dirac cone, as well as on the type of trajectory (parallel or diagonal with respect to the two cones) in parameter space. This geometric phase reveals the coupling between the bands encoded in the structure of the wavefunctions.
Molecular Dynamics Simulation Studies of Electrolytes and Electrolyte...
Broader source: Energy.gov (indexed) [DOE]
and is lower than the barrier for opening EC cyclic radical. ReaxFF molecular dynamics simulations show similar barriers in gas and condensed phases for these reactions....
Atomic scale insight into the amorphous structure of Cu doped GeTe phase-change material
Zhang, Linchuan; Sa, Baisheng [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Zhou, Jian; Sun, Zhimei, E-mail: zmsun@buaa.edu.cn [School of Materials Science and Engineering, and Center for Integrated Computational Materials Engineering, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191 (China); Song, Zhitang [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-System and Information Technology, CAS, 200050 Shanghai (China)
2014-10-21T23:59:59.000Z
GeTe shows promising application as a recording material for phase-change nonvolatile memory due to its fast crystallization speed and extraordinary amorphous stability. To further improve the performance of GeTe, various transition metals, such as copper, have been doped in GeTe in recent works. However, the effect of the doped transition metals on the stability of amorphous GeTe is not known. Here, we shed light on this problem for the system of Cu doped GeTe by means of ab initio molecular dynamics calculations. Our results show that the doped Cu atoms tend to agglomerate in amorphous GeTe. Further, base on analyzing the pair correlation functions, coordination numbers and bond angle distributions, remarkable changes in the local structure of amorphous GeTe induced by Cu are obviously seen. The present work may provide some clues for understanding the effect of early transition metals on the local structure of amorphous phase-change compounds, and hence should be helpful for optimizing the structure and performance of phase-change materials by doping transition metals.
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.
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.
Comparison of collimation systems for small-angle neutron scattering
Seeger, P.A.
1985-01-01T23:59:59.000Z
It is shown by simple first-order geometric arguments that for a given resolution, the flux on sample in a small-angle scattering instrument is independent of the form of the collimator or of the length of the instrument. Count rate may be increased by increasing the sample size, through the use of multi-aperture systems. In second order, it is shown to be advantageous to place the beam defining elements as close as possible to the source and the sample. The multiple-pinhole system gives maximum flux on small samples but has non-uniform illumination so that intensity increases only about half as fast as sample area. Soller slits and continuous tubes from source to sample were also considered, but neutron scattering and reflection from surfaces generate a large halo. Monte-Carlo simulations confirm these results, with the conclusion that the optimum collimator configuration is the multiple-pinhole system. 4 refs., 4 figs.
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.
Temperature-insensitive phase-matched optical harmonic conversion crystal
Barker, C.E.; Eimerl, D.; Velsko, S.P.; Roberts, D.
1993-11-23T23:59:59.000Z
Temperature-insensitive, phase-matched harmonic frequency conversion of laser light at a preferred wavelength of 1.064 microns can be achieved by use of a crystal of deuterated l-arginine phosphate. The crystal is cut and oriented so that the laser light propagates inside the crystal along one of several required directions, which correspond to a temperature-insensitive, phase-matching locus. The method of measuring and calculating the temperature-insensitive, phase-matching angles can be extended to other fundamental wavelengths and other crystal compositions. 12 figures.
Temperature-insensitive phase-matched optical harmonic conversion crystal
Barker, Charles E. (Sunnyvale, CA); Eimerl, David (Livermore, CA); Velsko, Stephan P. (Livermore, CA); Roberts, David (Sagamore Hills, OH)
1993-01-01T23:59:59.000Z
Temperature-insensitive, phase-matched harmomic frequency conversion of laser light at a preferred wavelength of 1.064 microns can be achieved by use of a crystal of deuterated l-arginine phosphate. The crystal is cut and oriented so that the laser light propagates inside the crystal along one of several required directions, which correspond to a temperature-insensitive, phase-matching locus. The method of measuring and calculating the temperature-insensitive, phase-matching angles can be extended to other fundamental wavelengths and other crystal compositions.
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.
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.
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.
Electronic Spectroscopy & Dynamics
Mark Maroncelli, Nancy Ryan Gray
2010-06-08T23:59:59.000Z
The Gordon Research Conference (GRC) on Electronic Spectroscopy and Dynamics was held at Colby College, Waterville, NH from 07/19/2009 thru 07/24/2009. The Conference was well-attended with participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. The GRC on Electronic Spectroscopy & Dynamics showcases some of the most recent experimental and theoretical developments in electronic spectroscopy that probes the structure and dynamics of isolated molecules, molecules embedded in clusters and condensed phases, and bulk materials. Electronic spectroscopy is an important tool in many fields of research, and this GRC brings together experts having diverse backgrounds in physics, chemistry, biophysics, and materials science, making the meeting an excellent opportunity for the interdisciplinary exchange of ideas and techniques. Topics covered in this GRC include high-resolution spectroscopy, biological molecules in the gas phase, electronic structure theory for excited states, multi-chromophore and single-molecule spectroscopies, and excited state dynamics in chemical and biological systems.
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
Phase-sensitive probes of nuclear polarization in spin-blockaded transport
Levitov, Leonid
Spin-blockaded quantum dots provide a unique setting for studying nuclear-spin dynamics in a nanoscale system. Despite recent experimental progress, observing phase-sensitive phenomena in nuclear spin dynamics remains ...
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.
Kent, B.; Garvey, C.J.; Cookson, D.; Bryant, G.; (Aust.Synch.); (ANSTO); (RMIT)
2009-01-05T23:59:59.000Z
The inverse hexagonal to inverse ribbon phase transition in a mixed phosphatidylcholine-phosphatidylethanolamine system at low hydration is studied using small and wide angle X-ray scattering. It is found that the structural parameters of the inverse hexagonal phase are independent of temperature. By contrast the length of each ribbon of the inverse ribbon phase increases continuously with decreasing temperature over a range of 50 C. At low temperatures the inverse ribbon phase is observed to have a transition to a gel lamellar phase, with no intermediate fluid lamellar phase. This phase transition is confirmed by differential scanning calorimetry.
aqueous polymer two-phase: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Universit de 3 Model of Two-Phase Flow and Flooding Dynamics in Polymer Electrolyte Fuel Cells Energy Storage, Conversion and Utilization Websites Summary: , 2005. Water...
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
Off-fault plasticity and earthquake rupture dynamics: 1. Dry materials or neglect of fluid pressure an explicit dynamic finite element procedure. A Mohr-Coulomb type elastic-plastic description describes-fault plasticity during dynamic rupture. Those include the angle with the fault of the maximum compressive
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.
Development of a hybrid margin angle controller for HVDC continuous operation
Sato, M. [Kansai Electric Power Co., Osaka (Japan)] [Kansai Electric Power Co., Osaka (Japan); Yamaji, K. [Shikoku Electric Power Co., Takamatsu (Japan)] [Shikoku Electric Power Co., Takamatsu (Japan); Sekita, M. [Electric Power Development Co., Tokyo (Japan)] [Electric Power Development Co., Tokyo (Japan); Amano, M.; Nishimura, M.; Konishi, H.; Oomori, T. [Hitachi, Ltd. (Japan)] [Hitachi, Ltd. (Japan)
1996-11-01T23:59:59.000Z
The objective of this paper is to present a new hybrid margin angle control method for HVDC continuous operation under AC system fault conditions. For stable continuous operation of HVDC systems, the margin angle controller must be designed to maintain the necessary margin angle to avoid commutation failures. The proposed method uses the open loop margin angle controller (MAC) as the basic controller, and adds output from the closed loop MAC to correct the control angle. A fast voltage detection algorithm is used for open loop control, and margin angle reference correction using harmonics detection for closed loop control are also developed. The combination of open and closed loop control provides quick responses when faults occur with stable and speedy recovery after fault clearance. The effectiveness of the developed controller is confirmed through EMTP digital simulations and also with the experiments using an analogue simulator.
Ultrasonic estimation of the contact angle of a sessile droplet
Quintero, R.; Simonetti, F. [Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH 45221 (United States)
2014-02-18T23:59:59.000Z
Radiation of energy by large amplitude leaky Rayleigh waves is regarded as one of the key physical mechanisms regulating the actuation and manipulation of droplets in surface acoustic wave (SAW) microfluidic devices. The interaction between a SAW and a droplet is highly complex and is presently the subject of extensive research. This paper investigates the existence of an additional interaction mechanism based on the propagation of quasi-Stoneley waves inside sessile droplets deposited on a solid substrate. In contrast with the leaky Rayleigh wave, the energy of the Stoneley wave is confined within a thin fluid layer in contact with the substrate. The hypothesis is confirmed by three-dimensional finite element simulations and ultrasonic scattering experiments measuring the reflection of Rayleigh waves from droplets of different diameters. Moreover, real-time monitoring of the droplet evaporation process reveals a clear correlation between the droplet contact angle and the spectral information of the reflected Rayleigh signal, thus paving the way for ultrasonic measurements of surface tension.
The XMM-Newton Wide Angle Survey (XWAS)
Esquej, P; Carrera, F J; Mateos, S; Tedds, J; Watson, M G; Corral, A; Ebrero, J; Krumpe, M; Rosen, S R; Ceballos, M T; Schwope, A; Page, C; Alonso-Herrero, A; Caccianiga, A; Della Ceca, R; Gonzalez-Martín, O; Lamer, G; Severgnini, P
2013-01-01T23:59:59.000Z
This programme is aimed at obtaining one of the largest X-ray selected samples of identified active galactic nuclei to date in order to characterise such a population at intermediate fluxes, where most of the Universe's accretion power originates. We present the XMM-Newton Wide Angle Survey (XWAS), a new catalogue of almost a thousand X-ray sources spectroscopically identified through optical observations. A sample of X-ray sources detected in 68 XMM-Newton pointed observations was selected for optical multi-fibre spectroscopy. Optical counterparts and corresponding photometry of the X-ray sources were obtained from the SuperCOSMOS Sky Survey. Candidates for spectroscopy were initially selected with magnitudes down to R~21, with preference for X-ray sources having a flux F(0.5-4.5 keV) >10^-14 erg s^-1 cm^-2. Optical spectroscopic observations performed at the Anglo Australian Telescope Two Degree Field were analysed, and the derived spectra were classified based on optical emission lines. We have identified ...
Measurements of the CKM Angle Alpha at BaBar
Stracka, Simone; /Milan U. /INFN, Milan; ,
2012-04-04T23:59:59.000Z
The authors present improved measurements of the branching fractions and CP-asymmetries fin the B{sup 0} {yields} {pi}{sup +}{pi}{sup -}, B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}, and B{sup +} {yields} {rho}{sup +}{rho}{sup 0} decays, which impact the determination of {alpha}. The combined branching fractions of B {yields} K{sub 1}(1270){pi} and B {yields} K{sub 1}(1400){pi} decays are measured for the first time and allow a novel determination of {alpha} in the B{sup 0} {yields} {alpha}{sub 1}(1260){sup {+-}}{pi}{sup {-+}} decay channel. These measurements are performed using the final dataset collected by the BaBar detector at the PEP-II B-factory. The primary goal of the experiments based at the B factories is to test the Cabibbo-Kobayashi-Maskawa (CKM) picture of CP violation in the standard model of electroweak interactions. This can be achieved by measuring the angles and sides of the Unitarity Triangle in a redundant way.
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.
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.
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 ...
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.
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.
atomic resolution high-angle: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
scattering of electrons CERN Preprints Summary: We consider theoretically the energy loss of electrons scattered to high angles when assuming that the primary beam can be...
angle deposited nano-rough: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Materials Science Websites Summary: the deposition angle, deposition rate, ro- tation speed, and material specific parameters such as surface deposition T. Karabacak,a) G.-C....
Visualizing quantum mechanics in phase space
Heiko Bauke; Noya Ruth Itzhak
2011-01-11T23:59:59.000Z
We examine the visualization of quantum mechanics in phase space by means of the Wigner function and the Wigner function flow as a complementary approach to illustrating quantum mechanics in configuration space by wave functions. The Wigner function formalism resembles the mathematical language of classical mechanics of non-interacting particles. Thus, it allows a more direct comparison between classical and quantum dynamical features.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Flynn, Connor
Shortwave Array Spectroradiometer-Hemispheric, VISible channel, low-sun angles [a0 data is uncalibrated
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Flynn, Connor
Shortwave Array Spectroradiometer-Hemispheric, VISible channel, high-sun angles [a0 data is uncalibrated
Andreas, Loren B.
We demonstrate the use of dynamic nuclear polarization (DNP) to elucidate ligand binding to a membrane protein using dipolar recoupling magic angle spinning (MAS) NMR. In particular, we detect drug binding in the proton ...
Ganguly, A.; Haldar, A.; Sinha, J.; Barman, A., E-mail: abarman@bose.res.in, E-mail: del.atkinson@durham.ac.uk [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700098 (India); Rowan-Robinson, R. M.; Jaiswal, S.; Hindmarch, A. T.; Atkinson, D. A., E-mail: abarman@bose.res.in, E-mail: del.atkinson@durham.ac.uk [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
2014-09-15T23:59:59.000Z
The effect of spin torque from the spin Hall effect in Pt/Ni{sub 81}Fe{sub 19} rectangular bilayer film was investigated using time-resolved magneto-optical Kerr microscopy. Current flow through the stack resulted in a linear variation of effective damping up to ±7%, attributed to spin current injection from the Pt into the Ni{sub 81}Fe{sub 19}. The spin Hall angle of Pt was estimated as 0.11?±?0.03. The modulation of the damping depended on the angle between the current and the bias magnetic field. These results demonstrate the importance of optical detection of precessional magnetization dynamics for studying spin transfer torque due to spin Hall effect.
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.
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...
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)
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.
Kravtsov, Yu. A. [Space Research Institute, Profsoyuznaya St. 82/34, Moscow 117997 (Russian Federation); Institute of Physics, Maritime University of Szczecin, Waly Chrobrego 1/., 70-500 Szczecin (Poland); Bieg, B. [Institute of Physics, Maritime University of Szczecin, Waly Chrobrego 1/., 70-500 Szczecin (Poland); Bliokh, K. Yu. [Institute of Radio Astronomy, 4 Krasnoznamyonnaya St., Kharkov 61002 (Ukraine); Optical Engineering Laboratory, Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Hirsch, M. [Max Planck Institute for Plasma Physics, Greifswald, Wendelsteinstrasse D-17491 (Germany)
2008-03-19T23:59:59.000Z
Three different theoretical approaches are presented: quasi-isotropic approximation (QIA), Stokes vector formalism and complex polarization angle method, which allow describing polarization of electromagnetic waves in weakly anisotropic plasma. QIA stems directly from the Maxwell equations under assumption of weak anisotropy and has a form of coupled differential equations for the transverse components of the electromagnetic wave field. Being applied to high frequency (microwave or IR) electromagnetic waves in magnetized plasma, QIA describes combined action of Faraday and Cotton-Mouton phenomena. QIA takes into account curvature and torsion of the ray, describes normal modes conversion in the inhomogeneous plasma and allows specifying area of applicability of the method.In distinction to QIA, Stokes vector formalism (SVF) deals with quantities, quadratic in a wave field. It is shown (and this is the main result of the paper) that equation for Stokes vector evolution can be derived directly from QIA. This evidences deep unity of two seemingly different approaches. In fact QIA suggests somewhat more information than SVF; in particular, it describes the phases of both transverse components of the electromagnetic field, whereas SVF operates only with the phase difference.At last, the coupled equations of the quasi-isotropic approximation can be reduced to a single equation for complex polarization angle (CPA), which describes both the shape and orientation of the polarization ellipse. In turn, equation for CPA allows obtaining equations for traditional parameters of polarization ellipse, which in fact are equivalent to the equation for Stokes vector evolution. It is pointed out that every method under discussion has its own advantages plasma polarimetry.
Complex Dynamics Bernardo Da Costa, Koushik Ramachandran, Jingjing Qu, and I had a two semester learning seminar in complex analysis and potential ...
Interface dynamics for layered structures
Takao Ohta; David Jasnow
1997-07-17T23:59:59.000Z
We investigate dynamics of large scale and slow deformations of layered structures. Starting from the respective model equations for a non-conserved system, a conserved system and a binary fluid, we derive the interface equations which are a coupled set of equations for deformations of the boundaries of each domain. A further reduction of the degrees of freedom is possible for a non-conserved system such that internal motion of each domain is adiabatically eliminated. The resulting equation of motion contains only the displacement of the center of gravity of domains, which is equivalent to the phase variable of a periodic structure. Thus our formulation automatically includes the phase dynamics of layered structures. In a conserved system and a binary fluid, however, the internal motion of domains turns out to be a slow variable in the long wavelength limit because of concentration conservation. Therefore a reduced description only involving the phase variable is not generally justified.
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
SAYA's head-eye coordination system Correspondence of image-width and angle
Beimel, Amos
SAYA's head-eye coordination system Correspondence of image-width and angle 335 - 359 [deg] 0 - 25 - 25 [deg] is input, head and eyes move to right side. b) If the angle within 335 - 359 [deg] is input, head and eyes move to left side. SAYA's head-eye coordination system Correspondence of image
Spectral Mapping of Protein Torsion Angles National High Magnetic Field Laboratory
Weston, Ken
Spectral Mapping of Protein Torsion Angles National High Magnetic Field Laboratory NMR Spectroscopy spectra. #12;Spectral Mapping of Protein Torsion Angles National High Magnetic Field Laboratory NMR, in recording signals that are dependent on the orientation of the atoms with respect to the magnetic field, we
Zender, Charles
Constraining MODIS snow albedo at large solar zenith angles: Implications for surface energy budget; Solar Zenith Angle; Greenland; Surface Energy Budget 2 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 plays a pivotal role in determining the surface energy balance of Greenland which, by virtue of its area
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
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
Light is said to be reflected when the angle at which light
Gilbes, Fernando
1 #12;2 Light is said to be reflected when the angle at which light initially strikes a surface is equal to the angle at which light bounces off the same surface. In the diagram, light strikes a surface", this is an example of reflected light. Refraction is the bending of a wave when it enters a medium where it's speed
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
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
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
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.
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
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
CFD Simulation of Dynamic Thrust and Radial Forces on a Vertical Axis Wind Turbine Blade
Tullis, Stephen
CFD Simulation of Dynamic Thrust and Radial Forces on a Vertical Axis Wind Turbine Blade K. Mc vibration source of a small scale vertical axis wind turbine. The dynamic loading on the blades of the turbine, as they rotate about the central shaft and travel through a range of relative angles of attack
Structure and Dynamics of Colliding Plasma Jets C. K. Li,1,* D. D. Ryutov,2
Structure and Dynamics of Colliding Plasma Jets C. K. Li,1,* D. D. Ryutov,2 S. X. Hu,3 M. J at various angles shed light on the structures and dynamics of these collisions. The observations compare noncollinear jets, the observed flow structure is similar to the analytic model's prediction of a character
Collective dynamics of active filament complexes
Nogucci, Hironobu
2015-01-01T23:59:59.000Z
Networks of biofilaments are essential for the formation of cellular structures and they support various biological functions. Previous studies have largely investigated the collective dynamics of rod-like biofilaments; however, the shapes of actual subcelluar componensts are often more elaborate. In this study, we investigated an active object composed of two active filaments, which represents a progression from rod-like biofilaments to complex-shaped biofilaments. Specifically, we numerically assessed the collective behaviors of these active objects and observed several types of dynamics depending on the density and the angle of the two filaments as shape parameters of the object. Among the observed collective dynamics, moving density bands that we named 'moving smectic' are reported here for the first time. By using statistical analyses of the orbits of individual objects and the interactions among them, the mechanisms underlying the rise of these dynamics patterns in the system were determined. This study...
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.
Gravitational waves from global second order phase transitions
Jr, John T. Giblin [Department of Physics, Kenyon College, 201 North College Rd, Gambier, OH 43022 (United States); Price, Larry R.; Siemens, Xavier; Vlcek, Brian, E-mail: giblinj@kenyon.edu, E-mail: larryp@caltech.edu, E-mail: siemens@gravity.phys.uwm.edu, E-mail: bvlcek@uwm.edu [Center for Gravitation and Cosmology, Department of Physics, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201 (United States)
2012-11-01T23:59:59.000Z
Global second-order phase transitions are expected to produce scale-invariant gravitational wave spectra. In this manuscript we explore the dynamics of a symmetry-breaking phase transition using lattice simulations. We explicitly calculate the stochastic gravitational wave background produced during the transition and subsequent self-ordering phase. We comment on this signal as it compares to the scale-invariant spectrum produced during inflation.
SDI: Statistical dynamic interactions
Blann, M.; Mustafa, M.G. (Lawrence Livermore National Lab., CA (USA)); Peilert, G.; Stoecker, H.; Greiner, W. (Frankfurt Univ. (Germany, F.R.). Inst. fuer Theoretische Physik)
1991-04-01T23:59:59.000Z
We focus on the combined statistical and dynamical aspects of heavy ion induced reactions. The overall picture is illustrated by considering the reaction {sup 36}Ar + {sup 238}U at a projectile energy of 35 MeV/nucleon. We illustrate the time dependent bound excitation energy due to the fusion/relaxation dynamics as calculated with the Boltzmann master equation. An estimate of the mass, charge and excitation of an equilibrated nucleus surviving the fast (dynamic) fusion-relaxation process is used as input into an evaporation calculation which includes 20 heavy fragment exit channels. The distribution of excitations between residue and clusters is explicitly calculated, as is the further deexcitation of clusters to bound nuclei. These results are compared with the exclusive cluster multiplicity measurements of Kim et al., and are found to give excellent agreement. We consider also an equilibrated residue system at 25% lower initial excitation, which gives an unsatisfactory exclusive multiplicity distribution. This illustrates that exclusive fragment multiplicity may provide a thermometer for system excitation. This analysis of data involves successive binary decay with no compressional effects nor phase transitions. Several examples of primary versus final (stable) cluster decay probabilities for an A = 100 nucleus at excitations of 100 to 800 MeV are presented. From these results a large change in multifragmentation patterns may be understood as a simple phase space consequence, invoking neither phase transitions, nor equation of state information. These results are used to illustrate physical quantities which are ambiguous to deduce from experimental fragment measurements. 14 refs., 4 figs.
Optimal PMU Placement Evaluation for Power System Dynamic State Estimation
Bishop, Gary
flow along the transmission lines or transformers. Â· Bus power injection measurements: the real of dis- tribution systems, the line current magnitude measurements (along the transmission lines. Â· Current phasor measurements: the phase angles and mag- nitudes of current phasors along transmission lines
Phase Transition in a Vlasov-Boltzmann Binary Mixture
R. Esposito; Y. Guo; R. Marra
2009-04-05T23:59:59.000Z
There are not many kinetic models where it is possible to prove bifurcation phenomena for any value of the Knudsen number. Here we consider a binary mixture over a line with collisions and long range repulsive interaction between different species. It undergoes a segregation phase transition at sufficiently low temperature. The spatially homogeneous Maxwellian equilibrium corresponding to the mixed phase, minimizing the free energy at high temperature, changes into a maximizer when the temperature goes below a critical value, while non homogeneous minimizers, corresponding to coexisting segregated phases, arise. We prove that they are dynamically stable with respect to the Vlasov-Boltzmann evolution, while the homogeneous equilibrium becomes dynamically unstable.
Phase Transition and Separation for Mixture of Liquid He-3 and He-4
Tian Ma; Shouhong Wang
2008-05-31T23:59:59.000Z
This article introduces a dynamical Ginzburg-Landau phase transition/separation model for the mixture of liquid helium-3 and helium-4, using a unified dynamical Ginzburg-Landau model for equilibrium phase transitions. The analysis of this model leads to three critical length scales L1 transition properties with different length scales of the container.
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.
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.
Achromatic phase matching at third orders of dispersion
Richman, Bruce
2003-10-21T23:59:59.000Z
Achromatic phase-matching (APM) is used for efficiently multiplying the frequency of broad bandwidth light by using a nonlinear optical medium comprising a second-harmonic generation (SHG) crystal and stationary optical elements whose configuration, properties, and arrangement have been optimized to match the angular dispersion characteristics of the SHG crystal to at least the third order. These elements include prisms and diffraction gratings for directing an input light beam onto the SHG crystal such that each ray wavelength is aligned to match the phase-matching angle for the crystal at each wavelength of light to at least the third order and such that every ray wavelength overlap within the crystal.
Geometric Phase Of The Faraday Rotation Of Electromagnetic Waves In Magnetized Plasma
Jian Liu and Hong Qin
2011-11-07T23:59:59.000Z
The geometric phase of circularly polarized electromagnetic waves in nonuniform magnetized plasmas is studied theoretically. The variation of the propagation direction of circularly polarized waves results in a geometric phase, which also contributes to the Faraday rotation, in addition to the standard dynamical phase. The origin and properties of the geometric phase is investigated. The in uence of the geometric phase to plasma diagnostics using Faraday rotation is also discussed as an application of the theory.
Clustering versus non-clustering phase synchronizations
Liu, Shuai [Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China) [Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhan, Meng, E-mail: zhanmeng@wipm.ac.cn [Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China)] [Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China)
2014-03-15T23:59:59.000Z
Clustering phase synchronization (CPS) is a common scenario to the global phase synchronization of coupled dynamical systems. In this work, a novel scenario, the non-clustering phase synchronization (NPS), is reported. It is found that coupled systems do not transit to the global synchronization until a certain sufficiently large coupling is attained, and there is no clustering prior to the global synchronization. To reveal the relationship between CPS and NPS, we further analyze the noise effect on coupled phase oscillators and find that the coupled oscillator system can change from CPS to NPS with the increase of noise intensity or system disorder. These findings are expected to shed light on the mechanism of various intriguing self-organized behaviors in coupled systems.
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.
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.
Employing feedback in adiabatic quantum dynamics
Armen E. Allahverdyan; Guenter Mahler
2008-04-10T23:59:59.000Z
We study quantum adiabatic dynamics, where the slowly moving field is influenced by system's state (feedback). The information for the feedback is gained from non-disturbating measurements done on an ensemble of identical non-interacting systems. The situation without feedback is governed by the adiabatic theorem: adiabatic energy level populations stay constant, while the adiabatic eigenvectors get a specific phase contribution (Berry phase). However, under feedback the adiabatic theorem does not hold: the adiabatic populations satisfy a closed equation of motion that coincides with the replicator dynamics well-known by its applications in evolutionary game theory. The feedback generates a new gauge-invariant adiabatic phase, which is free of the constraints on the Berry phase (e.g., the new phase is non-zero even for real adiabatic eigenfunctions).
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.
Surplus solid angle as an imprint of Horava-Lifshitz gravity
Kim, Sung-Soo; Kim, Taekyung; Kim, Yoonbai [Physique Theorique et Mathematique, Universite Libre de Bruxelles and International Solvay Institutes, ULB-C.P. 231, B-1050 Bruxelles (Belgium); Department of Physics, BK21 Physics Research Division, and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)
2009-12-15T23:59:59.000Z
We consider the electrostatic field of a point charge coupled to Horava-Lifshitz gravity and find an exact solution describing the space with a surplus (or deficit) solid angle. Although, theoretically in general relativity, a surplus angle is hardly to be obtained in the presence of ordinary matter with positive energy distribution, it seems natural in Horava-Lifshitz gravity. We present the sudden disappearance and reappearance of a star image as an astrophysical effect of a surplus angle. We also consider matter configurations of all possible power law behaviors coupled to Horava-Lifshitz gravity and obtain a series of exact solutions.
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 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.
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.
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...
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.
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.
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.
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.
Neutrino Oscillations With Recently Measured Sterile-Active Neutrino Mixing Angle
Leonard S. Kisslinger
2014-10-10T23:59:59.000Z
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.
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 ...
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 (
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.
Effect of catch-and-release angling on growth of largemouth bass, Micropterus salmoides
Wilde, Gene
- pterus salmoides Lace´ pe` de are reported. Because catch- and-release mortality is temperature dependent bass, Micropterus salmoides Lace´ pe` de. Angling mortality was 0.00 ± 0.092% for largemouth bass
Investigation of microstructure of disordered colloidal systems by small-angle scattering
Chiang, Wei-Shan
2014-01-01T23:59:59.000Z
Small-angle scattering (SAS) has been widely applied to study the microstructure of colloidal systems. Although colloids cover a wide range of materials, in general they can simply be viewed as basic building particles ...
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 ...
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 ...
[superscript 15]N-[superscript 15]N Proton Assisted Recoupling in Magic Angle Spinning NMR
Lewandowski, Jozef R.
We describe a new magic angle spinning (MAS) NMR experiment for obtaining [superscript 15]N?[superscript 15]N correlation spectra. The approach yields direct information about the secondary and tertiary structure of proteins, ...
Krill-eye : Superposition Compound Eye for Wide-Angle Imaging via GRIN Lenses
Hiura, Shinsaku
We propose a novel wide angle imaging system inspired by compound eyes of animals. Instead of using a single lens, well compensated for aberration, we used a number of simple lenses to form a compound eye which produces ...
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...
Microsoft Word - Milestone_Report-12-2012-Small-Angle_Neutron...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Water Reactor Sustainability Program: Milestone M3LW-13OR0402012, Report on Small-Angle Neutron Scattering Experiments of Irradiated RPV Materials Prepared by M. A. Sokolov, K....
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 ...
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
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
Geometric phases for non-degenerate and degenerate mixed states
K. Singh; D. M. Tong; K. Basu; J. L. Chen; J. F. Du
2003-04-10T23:59:59.000Z
This paper focuses on the geometric phase of general mixed states under unitary evolution. Here we analyze both non-degenerate as well as degenerate states. Starting with the non-degenerate case, we show that the usual procedure of subtracting the dynamical phase from the total phase to yield the geometric phase for pure states, does not hold for mixed states. To this end, we furnish an expression for the geometric phase that is gauge invariant. The parallelity conditions are shown to be easily derivable from this expression. We also extend our formalism to states that exhibit degeneracies. Here with the holonomy taking on a non-abelian character, we provide an expression for the geometric phase that is manifestly gauge invariant. As in the case of the non-degenerate case, the form also displays the parallelity conditions clearly. Finally, we furnish explicit examples of the geometric phases for both the non-degenerate as well as degenerate mixed states.
Ferrofluid nucleus phase transitions in an external uniform magnetic field
B. M. Tanygin; S. I. Shulyma; V. F. Kovalenko; M. V. Petrychuk
2015-02-18T23:59:59.000Z
Phase transition between massive dense phase and diluted superparamagnetic phase is studied by means of direct molecular dynamics simulation. Equilibrium structures of ferrofluid aggregate nucleus are obtained for different values of temperature and external magnetic field magnitude. For the ferrofluid phase diagram (coordinates "field-temperature"): approximate match of experiment and simulation is shown. Obtained phase coexistence curve has opposite trend compare to some of known theoretical results. This contradiction is related to postulating and comparing of the free energy of only simplest ferrofluid structures: diluted superparamagnetic phase, linear chains of the particles, and dense globes. The present results provide more fine structure of transition from "linear chains" to "dense globes" phase, e.g. through the ring assembly structure.
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.
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.
Angle-resolved scattering spectroscopy of explosives using an external cavity quantum cascade laser
Suter, Jonathan D.; Bernacki, Bruce E.; Phillips, Mark C.
2012-04-01T23:59:59.000Z
Investigation of angle-resolved scattering from solid explosives residues on a car door for non-contact sensing geometries. Illumination with a mid-infrared external cavity quantum cascade laser tuning between 7 and 8 microns was detected both with a sensitive single point detector and a hyperspectral imaging camera. Spectral scattering phenomena were discussed and possibilities for hyperspectral imaging at large scattering angles were outlined.
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...
The effects of diamond injector angles on flow structures at various Mach numbers
McLellan, Justin Walter
2006-10-30T23:59:59.000Z
THE EFFECTS OF DIAMOND INJECTOR ANGLES ON FLOW STRUCTURES AT VARIOUS MACH NUMBERS A Thesis by JUSTIN WALTER MCLELLAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 2005 Major Subject: Aerospace Engineering THE EFFECTS OF DIAMOND INJECTOR ANGLES ON FLOW STRUCTURES AT VARIOUS MACH NUMBERS A Thesis by JUSTIN WALTER...
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.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Flynn, Connor
Shortwave Array Spectroradiometer-Hemispheric, Near-InfraRed channel, high-sun angles [a0 data is uncalibrated
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Flynn, Connor
Shortwave Array Spectroradiometer-Hemispheric, Near-InfraRed channel, low-sun angles [a0 data is uncalibrated
Real-Time Magnetic Field Pitch Angle Estimation with a Motional Stark Effect Diagnostic Using Kalman Filtering
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 $Q^{2}=1.0Gev^{2}$
Evaluation of the Faraday Angle by Numerical Methods and Comparison with the Tore Supra and JET Polarimeter Electronics
Ab initio lattice dynamics and structural stability of MgO Artem R. Oganova)
Oganov, Artem R.
Ab initio lattice dynamics and structural stability of MgO Artem R. Oganova) Department of Earth GPa. The B2-structured phase is dynamically unstable below 110 GPa, but becomes dynamically stable-functional perturbation theory, we have studied lattice dynamics, dielectric and thermodynamic properties, and P
Keller, Ursula
for broadband excitation. We find that the pump-induced phase changes at the exciton and in the continuum decay chopping and lock-in detection. In our setup, phase dynamics can be studied in a temporal window limited, we have studied phase and amplitude semiconductor nonlinearities for broadband excitation of ex
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.
Kofinas, Peter
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
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
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.
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.
Power system identification toolbox: Phase two progress
Trudnowski, D.J.
1994-08-01T23:59:59.000Z
This report describes current progress on a project funded by the Bonneville Power Administration (BPA) to develop a set of state-of-the-art analysis software (termed the Power System Identification [PSI] Toolbox) for fitting dynamic models to measured data. The project is being conducted as a three-phase effort. The first phase, completed in late 1992, involved investigating the characteristics of the analysis techniques by evaluating existing software and developing guidelines for best use. Phase Two includes extending current software, developing new analysis algorithms and software, and demonstrating and developing applications. The final phase will focus on reorganizing the software into a modular collection of documented computer programs and developing user manuals with instruction and application guidelines. Phase Two is approximately 50% complete; progress to date and a vision for the final product of the PSI Toolbox are described. The needs of the power industry for specialized system identification methods are particularly acute. The industry is currently pushing to operate transmission systems much closer to theoretical limits by using real-time, large-scale control systems to dictate power flows and maintain dynamic stability. Reliably maintaining stability requires extensive system-dynamic modeling and analysis capability, including measurement-based methods. To serve this need, the BPA has developed specialized system-identification computer codes through in-house efforts and university contract research over the last several years. To make full integrated use of the codes, as well as other techniques, the BPA has commissioned Pacific Northwest Laboratory (PNL) to further develop the codes and techniques into the PSI Toolbox.
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.
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.
Li, Mo
Advance Digital Imaging Process for Tungsten Alloys Liquid-Phase Sintered in Microgravity W. B is to develop a digital image processing algorithm to rapidly detect and measure dihedral angles in binary. This geometric parameter greatly affects the liquid-phase sintering (LPS) process which is commonly used
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.
Modal aerosol dynamics modeling
Whitby, E.R.; McMurry, P.H.; Shankar, U.; Binkowski, F.S.
1991-02-01T23:59:59.000Z
The report presents the governing equations for representing aerosol dynamics, based on several different representations of the aerosol size distribution. Analytical and numerical solution techniques for these governing equations are also reviewed. Described in detail is a computationally efficient numerical technique for simulating aerosol behavior in systems undergoing simultaneous heat transfer, fluid flow, and mass transfer in and between the gas and condensed phases. The technique belongs to a general class of models known as modal aerosol dynamics (MAD) models. These models solve for the temporal and spatial evolution of the particle size distribution function. Computational efficiency is achieved by representing the complete aerosol population as a sum of additive overlapping populations (modes), and solving for the time rate of change of integral moments of each mode. Applications of MAD models for simulating aerosol dynamics in continuous stirred tank aerosol reactors and flow aerosol reactors are provided. For the application to flow aerosol reactors, the discussion is developed in terms of considerations for merging a MAD model with the SIMPLER routine described by Patankar (1980). Considerations for incorporating a MAD model into the U.S. Environmental Protection Agency's Regional Particulate Model are also described. Numerical and analytical techniques for evaluating the size-space integrals of the modal dynamics equations (MDEs) are described. For multimodal logonormal distributions, an analytical expression for the coagulation integrals of the MDEs, applicable for all size regimes, is derived, and is within 20% of accurate numerical evaluation of the same moment coagulation integrals. A computationally efficient integration technique, based on Gauss-Hermite numerical integration, is also derived.
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.
Holographic Magnetic Phase Transition
Gilad Lifschytz; Matthew Lippert
2009-06-21T23:59:59.000Z
We study four-dimensional interacting fermions in a strong magnetic field, using the holographic Sakai-Sugimoto model of intersecting D4 and D8 branes in the deconfined, chiral-symmetric parallel phase. We find that as the magnetic field is varied, while staying in the parallel phase, the fermions exhibit a first-order phase transition in which their magnetization jumps discontinuously. Properties of this transition are consistent with a picture in which some of the fermions jump to the lowest Landau level. Similarities to known magnetic phase transitions are discussed.
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Requirements" " " "Phase Two - Initial Project Development" "Replace Std Task 2-1","DO RFP Development - On Site Consultation","FEMP Services will provide technical consultation...
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.
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.
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.
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.
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.
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. ...
Jiangyong Jia; Peng Huo
2014-03-24T23:59:59.000Z
We argue that the transverse shape of the fireball created in heavy ion collision is controlled by event-by-event fluctuations of the eccentricity vectors for the forward-going and backward-going wounded nucleons: $\\vec{\\epsilon}_n^{\\mathrm{F}}\\equiv \\epsilon_n^{\\mathrm{F}} e^{i n\\Phi_n^{\\mathrm{*F}}}$ and $\\vec{\\epsilon}_n^{\\mathrm{B}}\\equiv \\epsilon_n^{\\mathrm{B}} e^{i n\\Phi_n^{\\mathrm{*B}}}$. Due to the asymmetric energy deposition of each wounded nucleon along its direction of motion, the eccentricity vector of the produced fireball is expected to interpolate between $\\vec{\\epsilon}_n^{\\mathrm{F}}$ and $\\vec{\\epsilon}_n^{\\mathrm{B}}$ along the pseudorapidity, and hence exhibits sizable forward-backward(FB) asymmetry ($\\epsilon_n^{\\rm B}\
Dynamical failure of Turing patterns
Alon Manor; Nadav M. Shnerb
2006-05-21T23:59:59.000Z
The emergence of stable disordered patterns in reactive system on spatially homogenous substrate is studied in the context of vegetation patterns in the semi-arid climatic zone. It is shown that reaction-diffusion systems that allow for Turing instability may exhibit heterogeneous "glassy" steady state, with no characteristic wavelength, if the diffusion rate associated with the "slow" reactant is very small. Upon decreasing the diffusion constant of the slow reactant three phases are identified: strong diffusion yields a stable homogenous phase, intermediate diffusion implies Turing (crystal like) patterns while in the slow diffusion limit the glassy state is the generic stable solution. In this disordered phase the dynamics is of crucial importance, with strong differences between local and global initiation.
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.
Application of computational fluid dynamics to aerosol sampling and concentration
Hu, Shishan
2009-05-15T23:59:59.000Z
An understanding of gas-liquid two-phase interactions, aerosol particle deposition, and heat transfer is needed. Computational Fluid Dynamics (CFD) is becoming a powerful tool to predict aerosol behavior for related design work. In this study...
Transmission Services WIST Task Force Dynamic Transfer Capability...
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WIST Task Force Dynamic Transfer Capability Report - Phase I BPA is an active participant in the Wind Integration Study Team (WIST), especially the Task Force looking at DTC study...
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.
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.
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.
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.
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.
Radiative Generation of Quark Masses and Mixing Angles in the Two Higgs Doublet Model
Alejandro Ibarra; Ana Solaguren-Beascoa
2014-07-04T23:59:59.000Z
We present a framework to generate the quark mass hierarchies and mixing angles by extending the Standard Model with one extra Higgs doublet. The charm and strange quark masses are generated by small quantum effects, thus explaining the hierarchy between the second and third generation quark masses. All the mixing angles are also generated by small quantum effects: the Cabibbo angle is generated at zero-th order in perturbation theory, while the remaining off-diagonal entries of the Cabibbo-Kobayashi-Maskawa matrix are generated at first order, hence explaining the observed hierarchy $|V_{ub}|,|V_{cb}|\\ll |V_{us}|$. The values of the radiatively generated parameters depend only logarithmically on the heavy Higgs mass, therefore this framework can be reconciled with the stringent limits on flavor violation by postulating a sufficiently large new physics scale.
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.
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.
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.
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
Kammler, Hendrik K.; Beaucage, Gregory; Kohls, Douglas J.; Agashe, Nikhil; Ilavsky, Jan [Particle Technology Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, ML F23, CH-8092 Zurich (Switzerland); Department of Chemical and Materials Engineering, University of Cincinnati, 540 Engineering Research Center, Cincinnati, Ohio 45221-0012 (United States); UNICAT, Advanced Photon Source, Building 438D, 9700 South Cass Avenue, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
2005-03-01T23:59:59.000Z
Ultra-small-angle x-ray scattering can provide information about primary particles and aggregates from a single scattering experiment. This technique is applied in situ to flame aerosol reactors for monitoring simultaneously the primary particle and aggregate growth dynamics of oxide nanoparticles in a flame. This was enabled through the use of a third generation synchrotron source (Advanced Photon Source, Argonne IL, USA) using specialized scattering instrumentation at the UNICAT facility which is capable of simultaneously measuring nanoscales to microscales (1 nm to 1 {mu}m). More specifically, the evolution of primary-particle diameter, mass-fractal dimension, geometric standard deviation, silica volume fraction, number concentration, radius of gyration of the aggregate, and number of primary particles per aggregate are measured along the flame axis for two different premixed flames. All these particle characteristics were derived from a single and nonintrusive measurement technique. Flame temperature profiles were measured in the presence of particles by in situ Fourier transform infrared spectroscopy and thermophoretic sampling was used to visualize particle growth with height above the burner as well as in the radial direction.
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.
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.
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.
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.
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.
An ab initio molecular orbital study of metal nitrosyl bond angles in iron complexes
Hawkins, Tommy Wayne
1979-01-01T23:59:59.000Z
I An ab initio molecular orbital study of the series [Fe(NO)CN)4] (N = 1, 2, 3) and [Fe(NO)Z(CN)ZN)] is made with emphasis on the effect of iron nitrosyl bond angle on electronic structure. In the [FeNO} 6 1- case, [Fe(NO)(CN)4] , there is a potential... barrier to bending of the nitrosyl which is consistent with existing models of transition metal 7 2- nitrosyl bonding. The [FeNO} complex, [Fe(NO) (CN)4] shows no sigrdficant barrier to moderate nitrosyl bending (up to an Fe-N-0 angle of 130 '), while...
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.
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.
Global Dynamics in Galactic Triaxial Systems I
Pablo M. Cincotta; Claudia M. Giordano; Josefa Perez; .
2006-04-21T23:59:59.000Z
In this paper we present a theoretical analysis of the global dynamics in a triaxial galactic system using a 3D integrable Hamiltonian as a simple representation. We include a thorough discussion on the effect of adding a generic non--integrable perturbation to the global dynamics of the system. We adopt the triaxial Stackel Hamiltonian as the integrable model and compute its resonance structure in order to understand its global dynamics when a perturbation is introduced. Also do we take profit of this example in order to provide a theoretical discussion about diffussive processes taking place in phase space.
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.
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.
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.
Implementing Turing Machines in Dynamic Field Architectures
Graben, Peter beim
2012-01-01T23:59:59.000Z
Cognitive computation such as e.g. language processing, is conventionally regarded as Turing computation, and Turing machines can be uniquely implemented as nonlinear dynamical systems using generalized shifts and subsequent G\\"odel encoding of the symbolic repertoire. The resulting nonlinear dynamical automata (NDA) are piecewise affine-linear maps acting on the unit square that is partitioned into rectangular domains. Iterating a single point, i.e. a microstate, by the dynamics yields a trajectory of, in principle, infinitely many points scattered through phase space. Therefore, the NDAs microstate dynamics does not necessarily terminate in contrast to its counterpart, the symbolic dynamics obtained from the rectangular partition. In order to regain the proper symbolic interpretation, one has to prepare ensembles of randomly distributed microstates with rectangular supports. Only the resulting macrostate evolution corresponds then to the original Turing machine computation. However, the introduction of rand...
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 ...
Dynamics of interacting dark energy model in Einstein and Loop Quantum Cosmology
Songbai Chen; Bin Wang; Jiliang Jing
2008-11-10T23:59:59.000Z
We investigate the background dynamics when dark energy is coupled to dark matter in the universe described by Einstein cosmology and Loop Quantum Cosmology. We introduce a new general form of dark sector coupling, which presents us a more complicated dynamical phase space. Differences in the phase space in obtaining the accelerated scaling attractor in Einstein cosmology and Loop Quantum Cosmology are disclosed.
Cosmological dynamical systems
Genly Leon; Carlos R. Fadragas
2014-12-18T23:59:59.000Z
In this book are studied, from the perspective of the dynamical systems, several Universe models. In chapter 1 we give a bird's eye view on cosmology and cosmological problems. Chapter 2 is devoted to a brief review on some results and useful tools from the qualitative theory of dynamical systems. They provide the theoretical basis for the qualitative study of concrete cosmological models. Chapters 1 and 2 are a review of well-known results. Chapters 3, 4, 5 and 6 are devoted to our main results. In these chapters are extended and settled in a substantially different, more strict mathematical language, several results obtained by one of us in arXiv:0812.1013 [gr-qc]; arXiv:1009.0689 [gr-qc]; arXiv:0904.1577[gr-qc]; and arXiv:0909.3571 [hep-th]. In chapter 6, we provide a different approach to the subject discussed in astro-ph/0503478. Additionally, we perform a Poincar\\'e compactification process allowing to construct a global phase space containing all the cosmological information in both finite and infinite regions for all the models.
Wigner representation of the rotational dynamics of rigid tops
Dmitry V. Zhdanov; Tamar Seideman
2014-06-15T23:59:59.000Z
We propose the general methodology to design the Wigner representations with the desired dynamical and semiclassical properties in the phase spaces with nontrivial topology. As an illustration, two representations of molecular rotations are developed to suit the computational demands of contemporary applications of laser alignment, diagnostics of reaction dynamics, studies of scattering and dissipative processes.
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