Automatic Generation of OpenMP Directives and Its Application to Computational Fluid Dynamics Codes
NASA Technical Reports Server (NTRS)
Yan, Jerry; Jin, Haoqiang; Frumkin, Michael; Yan, Jerry (Technical Monitor)
2000-01-01
The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. As great progress was made in hardware and software technologies, performance of parallel programs with compiler directives has demonstrated large improvement. The introduction of OpenMP directives, the industrial standard for shared-memory programming, has minimized the issue of portability. In this study, we have extended CAPTools, a computer-aided parallelization toolkit, to automatically generate OpenMP-based parallel programs with nominal user assistance. We outline techniques used in the implementation of the tool and discuss the application of this tool on the NAS Parallel Benchmarks and several computational fluid dynamics codes. This work demonstrates the great potential of using the tool to quickly port parallel programs and also achieve good performance that exceeds some of the commercial tools.
2012-01-01
Computer Assisted Structure Elucidation has been used for decades to discover the chemical structure of unknown compounds. In this work we introduce the first open source structure generator, Open Molecule Generator (OMG), which for a given elemental composition produces all non-isomorphic chemical structures that match that elemental composition. Furthermore, this structure generator can accept as additional input one or multiple non-overlapping prescribed substructures to drastically reduce the number of possible chemical structures. Being open source allows for customization and future extension of its functionality. OMG relies on a modified version of the Canonical Augmentation Path, which grows intermediate chemical structures by adding bonds and checks that at each step only unique molecules are produced. In order to benchmark the tool, we generated chemical structures for the elemental formulas and substructures of different metabolites and compared the results with a commercially available structure generator. The results obtained, i.e. the number of molecules generated, were identical for elemental compositions having only C, O and H. For elemental compositions containing C, O, H, N, P and S, OMG produces all the chemically valid molecules while the other generator produces more, yet chemically impossible, molecules. The chemical completeness of the OMG results comes at the expense of being slower than the commercial generator. In addition to being open source, OMG clearly showed the added value of constraining the solution space by using multiple prescribed substructures as input. We expect this structure generator to be useful in many fields, but to be especially of great importance for metabolomics, where identifying unknown metabolites is still a major bottleneck. PMID:22985496
Peironcely, Julio E; Rojas-Chertó, Miguel; Fichera, Davide; Reijmers, Theo; Coulier, Leon; Faulon, Jean-Loup; Hankemeier, Thomas
2012-01-01
Computer Assisted Structure Elucidation has been used for decades to discover the chemical structure of unknown compounds. In this work we introduce the first open source structure generator, Open Molecule Generator (OMG), which for a given elemental composition produces all non-isomorphic chemical structures that match that elemental composition. Furthermore, this structure generator can accept as additional input one or multiple non-overlapping prescribed substructures to drastically reduce the number of possible chemical structures. Being open source allows for customization and future extension of its functionality. OMG relies on a modified version of the Canonical Augmentation Path, which grows intermediate chemical structures by adding bonds and checks that at each step only unique molecules are produced. In order to benchmark the tool, we generated chemical structures for the elemental formulas and substructures of different metabolites and compared the results with a commercially available structure generator. The results obtained, i.e. the number of molecules generated, were identical for elemental compositions having only C, O and H. For elemental compositions containing C, O, H, N, P and S, OMG produces all the chemically valid molecules while the other generator produces more, yet chemically impossible, molecules. The chemical completeness of the OMG results comes at the expense of being slower than the commercial generator. In addition to being open source, OMG clearly showed the added value of constraining the solution space by using multiple prescribed substructures as input. We expect this structure generator to be useful in many fields, but to be especially of great importance for metabolomics, where identifying unknown metabolites is still a major bottleneck. PMID:22985496
NASA Astrophysics Data System (ADS)
Pashitskii, É. A.
2010-06-01
Based on a general model of nonlinear vortex dynamics in open thermodynamically nonequilibrium systems with bulk or surface mass losses, an analysis is presented of the mechanism of generation of violent atmospheric vortices (tornadoes, typhoons, cyclones) associated with the formation of deep cloud systems by intense condensation of water vapor from moist air cooled below the dew point. Simple particular solutions to the Navier-Stokes equations are found that describe both axisymmetric and nonaxisymmetric incompressible vortex motions involving radial and vertical flows with viscous dissipation vanishing identically everywhere except for a thin shear layer at the boundary of the condensation region. It is shown that the nonlinear convective and local Coriolis forces generated by radial inflow in the presence of a background vorticity due to a global Coriolis force (the Earth’s rotation) accelerate the solid-body rotation in the vortex core either exponentially or in a nonlinear regime of finite-time blow-up. Due to updrafts, such a vortex is characterized by a strong helicity. This mechanism explains a number of observed properties and characteristics of the structure and evolution of tornadoes and typhoons. Upper estimates are found for the kinetic energies of violent atmospheric vortices. It is shown that increase in rotational kinetic energy of atmospheric vortices with constant vortex-core radii is consistent with energy and momentum conservation, because radial inflow continually supplies the required amount of rotational kinetic energy drawn from the ambient atmosphere to an open system.
Pashitskii, E. A.
2010-06-15
Based on a general model of nonlinear vortex dynamics in open thermodynamically nonequilibrium systems with bulk or surface mass losses, an analysis is presented of the mechanism of generation of violent atmospheric vortices (tornadoes, typhoons, cyclones) associated with the formation of deep cloud systems by intense condensation of water vapor from moist air cooled below the dew point. Simple particular solutions to the Navier-Stokes equations are found that describe both axisymmetric and nonaxisymmetric incompressible vortex motions involving radial and vertical flows with viscous dissipation vanishing identically everywhere except for a thin shear layer at the boundary of the condensation region. It is shown that the nonlinear convective and local Coriolis forces generated by radial inflow in the presence of a background vorticity due to a global Coriolis force (the Earth's rotation) accelerate the solid-body rotation in the vortex core either exponentially or in a nonlinear regime of finite-time blow-up. Due to updrafts, such a vortex is characterized by a strong helicity. This mechanism explains a number of observed properties and characteristics of the structure and evolution of tornadoes and typhoons. Upper estimates are found for the kinetic energies of violent atmospheric vortices. It is shown that increase in rotational kinetic energy of atmospheric vortices with constant vortex-core radii is consistent with energy and momentum conservation, because radial inflow continually supplies the required amount of rotational kinetic energy drawn from the ambient atmosphere to an open system.
Open boundary molecular dynamics
NASA Astrophysics Data System (ADS)
Delgado-Buscalioni, R.; Sablić, J.; Praprotnik, M.
2015-09-01
This contribution analyzes several strategies and combination of methodologies to perform molecular dynamic simulations in open systems. Here, the term open indicates that the total system has boundaries where transfer of mass, momentum and energy can take place. This formalism, which we call Open Boundary Molecular Dynamics (OBMD), can act as interface of different schemes, such as Adaptive Resolution Scheme (AdResS) and Hybrid continuum-particle dynamics to link atomistic, coarse-grained (CG) and continuum (Eulerian) fluid dynamics in the general framework of fluctuating Navier-Stokes equations. The core domain of the simulation box is solved using all-atom descriptions. The CG layer introduced using AdResS is located at the outer part of the open box to make feasible the insertion of large molecules into the system. Communications between the molecular system and the outer world are carried out in the outer layers, called buffers. These coupling preserve momentum and mass conservation laws and can thus be linked with Eulerian hydro- dynamic solvers. In its simpler form, OBMD allows, however, to impose a local pressure tensor and a heat flux across the system's boundaries. For a one component molecular system, the external normal pressure and temperature determine the external chemical potential and thus the independent parameters of a grand-canonical ensemble simulation. Extended ensembles under non-equilibrium stationary states can also be simulated as well as time dependent forcings (e.g. oscillatory rheology). To illustrate the robustness of the combined OBMD-AdResS method, we present simulations of star-polymer melts at equilibrium and in sheared flow.
NASA Astrophysics Data System (ADS)
Liang, Wei-Hong; Xiao, C. W.; Oset, E.
2016-05-01
In this talk we review the results about the interaction of B ¯N , B ¯Δ, B ¯*N and B ¯*Δ states with beauty B = 1, together with their coupled channels, using the extended local hidden gauge approach. The Λb(5912) and Λb(5920) observed in the experiment are dynamically generated from the meson-baryon interaction, and they couple mostly to B ¯*N , which are degenerate with the Weinberg-Tomozawa interaction. In addition, three more states with I = 0 and eight more states with I = 1 are predicted.
Bashir, A.; Raya, A.
2006-09-25
Understanding the origin of mass, in particular that of the fermions, is one of the most uncanny problems which lie at the very frontiers of particle physics. Although the celebrated Standard Model accommodates these masses in a gauge invariant fashion, it fails to predict their values. Moreover, the mass thus generated accounts for only a very small percentage of the mass which permeates the visible universe. Most of the observed mass is accounted for by the strong interactions which bind quarks into protons and neutrons. How does that exactly happen in its quantitative details is still an unsolved mystery. Lattice formulation of quantum chromodynamics (QCD) or continuum studies of its Schwinger-Dyson equations (SDEs) are two of the non-perturbative means to try to unravel how quarks, starting from negligible current masses can acquire enormously large constituent masses to account for the observed proton and neutron masses. Analytical studies of SDEs in this context are extremely hard as one has to resort to truncation schemes whose quantitative reliability can be established only after a very careful analysis. Let alone the far more complicated realm of QCD, arriving at reliable truncation schemes in simpler scenarios such as quantum electrodynamics (QED) has also proved to be a hard nut to crack. In the last years, there has been an increasing group of physicists in Mexico which is taking up the challenge of understanding how the dynamical generation of mass can be understood in a reliable way through SDEs of gauge theories in various contexts such as (i) in arbitrary space-time dimensions d as well as d {<=} 4 (ii) finite temperatures and (ii) in the presence of magnetic fields. In this article, we summarise some of this work.
Dynamical semigroup for unbounded repeated perturbation of an open system
NASA Astrophysics Data System (ADS)
Tamura, Hiroshi; Zagrebnov, Valentin A.
2016-02-01
We consider a dynamical semigroup for unbounded Kossakowski-Lindblad-Davies generator corresponding to evolution of an open system for a tuned repeated harmonic perturbation. For this evolution, we prove the existence of uniquely determined minimal trace-preserving strongly continuous dynamical semigroups on the space of states. The corresponding dual W∗-dynamical system is shown to be unital quasi-free and completely positive automorphisms of the canonical commutation relation-algebra.
Generational Dynamics and Librarianship: Managing Generation X.
ERIC Educational Resources Information Center
Cooper, Julie F.; Cooper, Eric A.
1998-01-01
Explores the abilities of Generation X (individuals born 1961 to 1981) librarians to respond to the evolving needs of society. Highlights include age demographics, generational attributes, technology, and the seniority system. (PEN)
Dynamical generation of pseudoscalar resonances
Albaladejo, M.; Oller, J. A.; Roca, L.
2010-11-01
We study the interactions between the f{sub 0}(980) and a{sub 0}(980) scalar resonances and the lightest pseudoscalar mesons. We first obtain the elementary interaction amplitudes, or interacting kernels, without including any ad hoc free parameter. This is achieved by using previous results on the nature of the lightest scalar resonances as dynamically generated from the rescattering of S-wave two-meson pairs. Afterwards, the interaction kernels are unitarized and the final S-wave amplitudes result. We find that these interactions are very rich and generate a large amount of pseudoscalar resonances that could be associated with the K(1460), {pi}(1300), {pi}(1800), {eta}(1475), and X(1835). We also consider the exotic channels with isospin 3/2 and 1, the latter having positive G-parity. The former could also be resonant in agreement with a previous prediction.
OCSEGen: Open Components and Systems Environment Generator
NASA Technical Reports Server (NTRS)
Tkachuk, Oksana
2014-01-01
To analyze a large system, one often needs to break it into smaller components.To analyze a component or unit under analysis, one needs to model its context of execution, called environment, which represents the components with which the unit interacts. Environment generation is a challenging problem, because the environment needs to be general enough to uncover unit errors, yet precise enough to make the analysis tractable. In this paper, we present a tool for automated environment generation for open components and systems. The tool, called OCSEGen, is implemented on top of the Soot framework. We present the tool's current support and discuss its possible future extensions.
Colloquium: Non-Markovian dynamics in open quantum systems
NASA Astrophysics Data System (ADS)
Breuer, Heinz-Peter; Laine, Elsi-Mari; Piilo, Jyrki; Vacchini, Bassano
2016-04-01
The dynamical behavior of open quantum systems plays a key role in many applications of quantum mechanics, examples ranging from fundamental problems, such as the environment-induced decay of quantum coherence and relaxation in many-body systems, to applications in condensed matter theory, quantum transport, quantum chemistry, and quantum information. In close analogy to a classical Markovian stochastic process, the interaction of an open quantum system with a noisy environment is often modeled phenomenologically by means of a dynamical semigroup with a corresponding time-independent generator in Lindblad form, which describes a memoryless dynamics of the open system typically leading to an irreversible loss of characteristic quantum features. However, in many applications open systems exhibit pronounced memory effects and a revival of genuine quantum properties such as quantum coherence, correlations, and entanglement. Here recent theoretical results on the rich non-Markovian quantum dynamics of open systems are discussed, paying particular attention to the rigorous mathematical definition, to the physical interpretation and classification, as well as to the quantification of quantum memory effects. The general theory is illustrated by a series of physical examples. The analysis reveals that memory effects of the open system dynamics reflect characteristic features of the environment which opens a new perspective for applications, namely, to exploit a small open system as a quantum probe signifying nontrivial features of the environment it is interacting with. This Colloquium further explores the various physical sources of non-Markovian quantum dynamics, such as structured environmental spectral densities, nonlocal correlations between environmental degrees of freedom, and correlations in the initial system-environment state, in addition to developing schemes for their local detection. Recent experiments addressing the detection, quantification, and control of
Dynamics of Mouth Opening in Hydra.
Carter, Jason A; Hyland, Callen; Steele, Robert E; Collins, Eva-Maria S
2016-03-01
Hydra, a simple freshwater animal famous for its regenerative capabilities, must tear a hole through its epithelial tissue each time it opens its mouth. The feeding response of Hydra has been well-characterized physiologically and is regarded as a classical model system for environmental chemical biology. However, due to a lack of in vivo labeling and imaging tools, the biomechanics of mouth opening have remained completely unexplored. We take advantage of the availability of transgenic Hydra lines to perform the first dynamical analysis, to our knowledge, of Hydra mouth opening and test existing hypotheses regarding the underlying cellular mechanisms. Through cell position and shape tracking, we show that mouth opening is accompanied by changes in cell shape, but not cellular rearrangements as previously suggested. Treatment with a muscle relaxant impairs mouth opening, supporting the hypothesis that mouth opening is an active process driven by radial contractile processes (myonemes) in the ectoderm. Furthermore, we find that all events exhibit the same relative rate of opening. Because one individual can open consecutively to different amounts, this suggests that the degree of mouth opening is controlled through neuronal signaling. Finally, from the opening dynamics and independent measurements of the elastic properties of the tissues, we estimate the forces exerted by the myonemes to be on the order of a few nanoNewtons. Our study provides the first dynamical framework, to our knowledge, for understanding the remarkable plasticity of the Hydra mouth and illustrates that Hydra is a powerful system for quantitative biomechanical studies of cell and tissue behaviors in vivo. PMID:26958895
Dynamics of very rich open clusters
NASA Astrophysics Data System (ADS)
de la Fuente Marcos, R.; de la Fuente Marcos, C.
The oldest open clusters in our Galaxy set the lower limit to the age of the Galactic Disk (9-10 Gyr). Although they appear to be very rich now, it is clear that their primordial populations were much larger. Often considered as transitional objects, these populous open clusters show structural differences with respect to globular clusters so their dynamics and characteristic evolutionary time scales can also be different. On the other hand, their large membership lead to different dynamical evolution as compared with average open clusters. In this paper, the differential features of the evolution of rich open clusters are studied using N-body simulations, including several of the largest (10^4 stars) published direct collisional N-body calculations so far, which were performed on a CRAY YMP. The disruption rate of rich open clusters is analysed in detail and the effect of the initial spatial distribution of the stars in the cluster on its dynamics is studied. The results show that cluster life-time depends on this initial distribution, decreasing when it is more concentrated. The effect of stellar evolution on the dynamical evolution of rich clusters is an important subject that also has been considered here. We demonstrate that the cluster's life-expectancy against evaporation increases because of mass loss by evolving high-mass stars.
Dynamic Participation in Interdistrict Open Enrollment
ERIC Educational Resources Information Center
Lavery, Lesley; Carlson, Deven
2015-01-01
Interdistrict open enrollment is the nation's largest and most widespread school choice program, but our knowledge of these programs is limited. Drawing on 5 years of student-level data from the universe of public school attendees in Colorado, we perform a three-stage analysis to examine the dynamics of student participation in the state's…
NASA Astrophysics Data System (ADS)
Luhmann, A. J.; Tutolo, B. M.; Bagley, B. C.; Mildner, D. F. R.; Seyfried, W. E., Jr.
2015-12-01
Tectonic processes often exhume mantle peridotite to environments near the Earth's surface, where serpentinization occurs and involves the hydration of peridotite at relatively low temperatures. This process oxidizes ferrous iron in olivine, which produces hydrogen (H2), creating environments that are conducive to abiotic synthesis of organic compounds and H2-based microbial communities. To understand better chemical and physical processes associated with serpentinization, two flow-through experiments (>30 days) were conducted at 150 and 200°C and 150 bar on intact dunite cores. Permeability decreased by a factor of 31 during the 200°C experiment, more than an order of magnitude larger than that at 150°C. Furthermore, H2 and methane concentrations exceeded 600 µmol/kg and 300 µmol/kg during the 200°C experiment, and were one and two orders of magnitude higher, respectively, than the 150°C experiment. H2 was primarily generated during the conversion of olivine to ferric serpentine at 200°C, since vibrating sample magnetometer analysis indicated little to no magnetite production. Secondary mineralization was identified on the core from this experiment, but X-ray computed tomography scans indicated little change. Furthermore, (ultra) small-angle neutron scattering datasets indicated that any change in nano-porosity and surface area was smaller than the natural variability of the dunite. Even though there was little evidence of alteration, the initial stage of serpentinization at 200°C was sufficient to produce a dramatic effect on flow fields in the core. Furthermore, this experiment generated significant dissolved H2 concentrations, while simulating open system dynamics. Thus, the experimental data provide insight on mass transfer processes in open geochemical systems, which effectively prevent highly elevated H2 concentrations due to continual loss. We speculate that this process is responsible for stabilizing unusually ferric-rich serpentine in nature.
Open Automated Demand Response Dynamic Pricing Technologies and Demonstration
Ghatikar, Girish; Mathieu, Johanna L.; Piette, Mary Ann; Koch, Ed; Hennage, Dan
2010-08-02
This study examines the use of OpenADR communications specification, related data models, technologies, and strategies to send dynamic prices (e.g., real time prices and peak prices) and Time of Use (TOU) rates to commercial and industrial electricity customers. OpenADR v1.0 is a Web services-based flexible, open information model that has been used in California utilities' commercial automated demand response programs since 2007. We find that data models can be used to send real time prices. These same data models can also be used to support peak pricing and TOU rates. We present a data model that can accommodate all three types of rates. For demonstration purposes, the data models were generated from California Independent System Operator's real-time wholesale market prices, and a California utility's dynamic prices and TOU rates. Customers can respond to dynamic prices by either using the actual prices, or prices can be mapped into"operation modes," which can act as inputs to control systems. We present several different methods for mapping actual prices. Some of these methods were implemented in demonstration projects. The study results demonstrate show that OpenADR allows interoperability with existing/future systems/technologies and can be used within related dynamic pricing activities within Smart Grid.
Towards a Theory of Metastability in Open Quantum Dynamics.
Macieszczak, Katarzyna; Guţă, Mădălin; Lesanovsky, Igor; Garrahan, Juan P
2016-06-17
By generalizing concepts from classical stochastic dynamics, we establish the basis for a theory of metastability in Markovian open quantum systems. Partial relaxation into long-lived metastable states-distinct from the asymptotic stationary state-is a manifestation of a separation of time scales due to a splitting in the spectrum of the generator of the dynamics. We show here how to exploit this spectral structure to obtain a low dimensional approximation to the dynamics in terms of motion in a manifold of metastable states constructed from the low-lying eigenmatrices of the generator. We argue that the metastable manifold is in general composed of disjoint states, noiseless subsystems, and decoherence-free subspaces. PMID:27367368
Towards a Theory of Metastability in Open Quantum Dynamics
NASA Astrophysics Data System (ADS)
Macieszczak, Katarzyna; GuÅ£ǎ, Mǎdǎlin; Lesanovsky, Igor; Garrahan, Juan P.
2016-06-01
By generalizing concepts from classical stochastic dynamics, we establish the basis for a theory of metastability in Markovian open quantum systems. Partial relaxation into long-lived metastable states—distinct from the asymptotic stationary state—is a manifestation of a separation of time scales due to a splitting in the spectrum of the generator of the dynamics. We show here how to exploit this spectral structure to obtain a low dimensional approximation to the dynamics in terms of motion in a manifold of metastable states constructed from the low-lying eigenmatrices of the generator. We argue that the metastable manifold is in general composed of disjoint states, noiseless subsystems, and decoherence-free subspaces.
Automatic Generation of Audio Content for Open Learning Resources
ERIC Educational Resources Information Center
Brasher, Andrew; McAndrew, Patrick
2009-01-01
This paper describes how digital talking books (DTBs) with embedded functionality for learners can be generated from content structured according to the OU OpenLearn schema. It includes examples showing how a software transformation developed from open source components can be used to remix OpenLearn content, and discusses issues concerning the…
Osmosis-Based Pressure Generation: Dynamics and Application
Li, Suyi; Billeh, Yazan N.; Wang, K. W.; Mayer, Michael
2014-01-01
This paper describes osmotically-driven pressure generation in a membrane-bound compartment while taking into account volume expansion, solute dilution, surface area to volume ratio, membrane hydraulic permeability, and changes in osmotic gradient, bulk modulus, and degree of membrane fouling. The emphasis lies on the dynamics of pressure generation; these dynamics have not previously been described in detail. Experimental results are compared to and supported by numerical simulations, which we make accessible as an open source tool. This approach reveals unintuitive results about the quantitative dependence of the speed of pressure generation on the relevant and interdependent parameters that will be encountered in most osmotically-driven pressure generators. For instance, restricting the volume expansion of a compartment allows it to generate its first 5 kPa of pressure seven times faster than without a restraint. In addition, this dynamics study shows that plants are near-ideal osmotic pressure generators, as they are composed of many small compartments with large surface area to volume ratios and strong cell wall reinforcements. Finally, we demonstrate two applications of an osmosis-based pressure generator: actuation of a soft robot and continuous volume delivery over long periods of time. Both applications do not need an external power source but rather take advantage of the energy released upon watering the pressure generators. PMID:24614529
Open dynamic behaviour of financial markets
NASA Astrophysics Data System (ADS)
Gong, F. F.; Gong, F. X.; Gong, F. Y.
2006-02-01
Open dynamic behaviour of financial markets with internal interactions between agents and with external “fields” from other systems are investigated using the approach of Grossman and Stiglitz for inefficient markets, and Keynes for interference of the market using physics of finance (referred to hereafter as phynance). The simulation results indicate that the NYSE data analyzed in Plerou, V. et al., Nature 421, 130 (2003) can be fitted by an equation of order parameter Φ and local deviation R of type: -(R+0.03) Φ+ 0.6 Φ3 + 0.02 = 0, which is shown to be in remarkable agreement with Plerou's data.
Electric voltage generation by antiferromagnetic dynamics
NASA Astrophysics Data System (ADS)
Yamane, Yuta; Ieda, Jun'ichi; Sinova, Jairo
2016-05-01
We theoretically demonstrate dc and ac electric voltage generation due to spin motive forces originating from domain wall motion and magnetic resonance, respectively, in two-sublattice antiferromagnets. Our theory accounts for the canting between the sublattice magnetizations, the nonadiabatic electron spin dynamics, and the Rashba spin-orbit coupling, with the intersublattice electron dynamics treated as a perturbation. This work suggests a way to observe and explore the dynamics of antiferromagnetic textures by electrical means, an important aspect in the emerging field of antiferromagnetic spintronics, where both manipulation and detection of antiferromagnets are needed.
Dynamics of Open DNA Sliding Clamps.
Oakley, Aaron J
2016-01-01
A range of enzymes in DNA replication and repair bind to DNA-clamps: torus-shaped proteins that encircle double-stranded DNA and act as mobile tethers. Clamps from viruses (such as gp45 from the T4 bacteriophage) and eukaryotes (PCNAs) are homotrimers, each protomer containing two repeats of the DNA-clamp motif, while bacterial clamps (pol III β) are homodimers, each protomer containing three DNA-clamp motifs. Clamps need to be flexible enough to allow opening and loading onto primed DNA by clamp loader complexes. Equilibrium and steered molecular dynamics simulations have been used to study DNA-clamp conformation in open and closed forms. The E. coli and PCNA clamps appear to prefer closed, planar conformations. Remarkably, gp45 appears to prefer an open right-handed spiral conformation in solution, in agreement with previously reported biophysical data. The structural preferences of DNA clamps in solution have implications for understanding the duty cycle of clamp-loaders. PMID:27148748
Dynamics of Open DNA Sliding Clamps
Oakley, Aaron J.
2016-01-01
A range of enzymes in DNA replication and repair bind to DNA-clamps: torus-shaped proteins that encircle double-stranded DNA and act as mobile tethers. Clamps from viruses (such as gp45 from the T4 bacteriophage) and eukaryotes (PCNAs) are homotrimers, each protomer containing two repeats of the DNA-clamp motif, while bacterial clamps (pol III β) are homodimers, each protomer containing three DNA-clamp motifs. Clamps need to be flexible enough to allow opening and loading onto primed DNA by clamp loader complexes. Equilibrium and steered molecular dynamics simulations have been used to study DNA-clamp conformation in open and closed forms. The E. coli and PCNA clamps appear to prefer closed, planar conformations. Remarkably, gp45 appears to prefer an open right-handed spiral conformation in solution, in agreement with previously reported biophysical data. The structural preferences of DNA clamps in solution have implications for understanding the duty cycle of clamp-loaders. PMID:27148748
Open Source, Meet "User-Generated Science"
ERIC Educational Resources Information Center
Huwe, Terence K.
2009-01-01
This article discusses Research Blogging, a community-run nonprofit organization that is promoting a suite of blogging software to scholars. Research Blogging itself does two things. First, it extends an invitation to a community, and it is open to anyone. Second, it requires its users to follow guidelines. The combination of rigorous guidelines…
Radiative decays of dynamically generated charmed baryons
Gamermann, D.; Jimenez-Tejero, C. E.; Ramos, A.
2011-04-01
In this work we study the radiative decay of dynamically generated J{sup P}=(1{sup -}/2) charm baryons into the ground state J{sup P}=(1{sup +}/2) baryons. Since different theoretical interpretations of these baryonic resonances and, in particular, of the {Lambda}{sub c}(2595), give different predictions, a precise experimental measurement of these decays would be an important step for understanding their nature.
Dynamic Open Inquiry Performances of High-School Biology Students
ERIC Educational Resources Information Center
Zion, Michal; Sadeh, Irit
2010-01-01
In examining open inquiry projects among high-school biology students, we found dynamic inquiry performances expressed in two criteria: "changes occurring during inquiry" and "procedural understanding". Characterizing performances in a dynamic open inquiry project can shed light on both the procedural and epistemological scientific understanding…
Dynamical Evolution of Open Star Clusters
NASA Astrophysics Data System (ADS)
de La Fuente Marcos, Raúl
1998-09-01
Stars are not formed independently, but instead they form in clusters. The influence of the initial mass function (IMF) on the evolution of open star clusters is analyzed using numerical integrations of N-body systems by the code NBODY5 (S. J. Aarseth, in Multiple Time Scales, ed. J. U. Brackbill & B. I. Cohen [New York: Academic, 1985], p. 377), which include tidal effects, mass loss due to stellar evolution, the realistic fraction of primordial binaries, and the formation of multiple systems. Five different IMFs (E. E. Salpeter, ApJ, 121, 161 [1955]; L. G. Taff, AJ, 79, 11 [1974]; G. E. Miller & J. M. Scalo, ApJS, 41, 513 [1979]; P. Kroupa, C. A. Tout, & G. Gilmore, MNRAS, 262, 545 [1993]; J. M. Scalo, Fundam. Cosmic Phys., 11, 1 [1986]) are used for generating stellar masses. The results confirm significant differences with single-mass models and allow us to distinguish between the standard power-law models and modern ones. An approximate analytic expression for the escape rate is derived in order to fit the data obtained. When stellar evolution is included, the results show that for all the IMF's studied, the evolution of the cluster is slowed down and the initial core collapse loses importance because of an expansion of the inner regions of the cluster. We find that the total disruption time is very IMF dependent because of different numbers of massive stars and also depends on the richness of the cluster. A differential behavior is found between poor and rich systems with respect to mass loss. Poor systems disrupt earlier than homologous ones without mass loss; the opposite is found for rich systems. The transition population is about N = 300. The binary escape rate seems preferentially due to close encounters in poor clusters, but it seems mainly exponential for populated clusters. It suggests that ejection is the main mechanism for binary escape in poor clusters and evaporation is the dominant one for rich clusters. The formation and evolution of
Dynamical gap generation in topological insulators
NASA Astrophysics Data System (ADS)
Cea, Paolo
2016-04-01
We developed a quantum field theoretical description for the surface states of three-dimensional topological insulators. Within the relativistic quantum field theory formulation, we investigated the dynamics of low-lying surface states in an applied transverse magnetic field. We argued that, by taking into account quantum fluctuations, in three-dimensional topological insulators there is dynamical generation of a gap by a rearrangement of the Dirac sea. By comparing with available experimental data we found that our theoretical results allowed a consistent and coherent description of the Landau level spectrum of the surface low-lying excitations. Finally, we showed that the recently detected zero-Hall plateau at the charge neutral point could be accounted for by chiral edge states residing at the magnetic domain boundaries between the top and bottom surfaces of the three-dimensional topological insulator.
Performance of a dynamic atmosphere generation system
Nano, G.; Borroni, A.; Mazza, B.
1987-09-01
A controlled test atmosphere system for gaseous pollutants was designed and constructed. For a reliable characterization of indoor air pollution, a suitable set of sampling and analysis procedures has to be devised and accomplished. The precision and accuracy of the measurements must be determined exactly for a correct interpretation of the results. The two main difficulties appear to be the actual generation of the individual standard and the preparations of physico-chemically thoroughly characterized mixtures. This system utilized two methods for generation of dynamic standards: permeation tubes and gas saturators. Special care also was devoted to the achievement of both a good time stability of the concentration of the standard mixtures and a satisfactory agreement between expected and measured concentration values.
33. Lower level, ballistic gas generator at left (opens launcher ...
33. Lower level, ballistic gas generator at left (opens launcher door during launch), LDB panel at right - Ellsworth Air Force Base, Delta Flight, Launch Facility, On County Road T512, south of Exit 116 off I-90, Interior, Jackson County, SD
A swirl generator case study for OpenFOAM
NASA Astrophysics Data System (ADS)
Petit, O.; Bosioc, A. I.; Nilsson, H.; Muntean, S.; Susan-Resiga, R. F.
2010-08-01
This work presents numerical results, using OpenFOAM, of the flow in the swirl flow generator test rig developed at Politehnica University of Timisoara, Romania. The work shows results computed by solving the unsteady Reynolds Averaged Navier Stokes equations. The unsteady method couples the rotating and stationary parts using a sliding grid interface based on a GGI formulation. Turbulence is modeled using the standard k-epsilon model, and block structured wall function ICEM-Hexa meshes are used. The numerical results are validated against experimental LDV results, and against designed velocity profiles. The investigation shows that OpenFOAM gives results that are comparable to the experimental and designed profiles. This case study was presented at the 5th OpenFOAM Workshop, held in Gothenburg, Sweden, as a tutorial on how to treat turbomachinery applications in OpenFOAM.
A platform for dynamic simulation and control of movement based on OpenSim and MATLAB.
Mansouri, Misagh; Reinbolt, Jeffrey A
2012-05-11
Numerical simulations play an important role in solving complex engineering problems and have the potential to revolutionize medical decision making and treatment strategies. In this paper, we combine the rapid model-based design, control systems and powerful numerical method strengths of MATLAB/Simulink with the simulation and human movement dynamics strengths of OpenSim by developing a new interface between the two software tools. OpenSim is integrated with Simulink using the MATLAB S-function mechanism, and the interface is demonstrated using both open-loop and closed-loop control systems. While the open-loop system uses MATLAB/Simulink to separately reproduce the OpenSim Forward Dynamics Tool, the closed-loop system adds the unique feature of feedback control to OpenSim, which is necessary for most human movement simulations. An arm model example was successfully used in both open-loop and closed-loop cases. For the open-loop case, the simulation reproduced results from the OpenSim Forward Dynamics Tool with root mean square (RMS) differences of 0.03° for the shoulder elevation angle and 0.06° for the elbow flexion angle. MATLAB's variable step-size integrator reduced the time required to generate the forward dynamic simulation from 7.1s (OpenSim) to 2.9s (MATLAB). For the closed-loop case, a proportional-integral-derivative controller was used to successfully balance a pole on model's hand despite random force disturbances on the pole. The new interface presented here not only integrates the OpenSim and MATLAB/Simulink software tools, but also will allow neuroscientists, physiologists, biomechanists, and physical therapists to adapt and generate new solutions as treatments for musculoskeletal conditions. PMID:22464351
Open Source Next Generation Visualization Software for Interplanetary Missions
NASA Technical Reports Server (NTRS)
Trimble, Jay; Rinker, George
2016-01-01
Mission control is evolving quickly, driven by the requirements of new missions, and enabled by modern computing capabilities. Distributed operations, access to data anywhere, data visualization for spacecraft analysis that spans multiple data sources, flexible reconfiguration to support multiple missions, and operator use cases, are driving the need for new capabilities. NASA's Advanced Multi-Mission Operations System (AMMOS), Ames Research Center (ARC) and the Jet Propulsion Laboratory (JPL) are collaborating to build a new generation of mission operations software for visualization, to enable mission control anywhere, on the desktop, tablet and phone. The software is built on an open source platform that is open for contributions (http://nasa.github.io/openmct).
Ambit-Tautomer: An Open Source Tool for Tautomer Generation.
Kochev, Nikolay T; Paskaleva, Vesselina H; Jeliazkova, Nina
2013-06-01
We present a new open source tool for automatic generation of all tautomeric forms of a given organic compound. Ambit-Tautomer is a part of the open source software package Ambit2. It implements three tautomer generation algorithms: combinatorial method, improved combinatorial method and incremental depth-first search algorithm. All algorithms utilize a set of fully customizable rules for tautomeric transformations. The predefined knowledge base covers 1-3, 1-5 and 1-7 proton tautomeric shifts. Some typical supported tautomerism rules are keto-enol, imin-amin, nitroso-oxime, azo-hydrazone, thioketo-thioenol, thionitroso-thiooxime, amidine-imidine, diazoamino-diazoamino, thioamide-iminothiol and nitrosamine-diazohydroxide. Ambit-Tautomer uses a simple energy based system for tautomer ranking implemented by a set of empirically derived rules. A fine-grained output control is achieved by a set of post-generation filters. We performed an exhaustive comparison of the Ambit-Tautomer Incremental algorithm against several other software packages which offer tautomer generation: ChemAxon Marvin, Molecular Networks MN.TAUTOMER, ACDLabs, CACTVS and the CDK implementation of the algorithm, based on the mobile H atoms listed in the InChI. According to the presented test results, Ambit-Tautomer's performance is either comparable to or better than the competing algorithms. Ambit-Tautomer module is available for download as a Java library, a command line application, a demo web page or OpenTox API compatible Web service. PMID:27481667
The new generation of OpenGL support in ROOT
NASA Astrophysics Data System (ADS)
Tadel, M.
2008-07-01
OpenGL has been promoted to become the main 3D rendering engine of the ROOT framework. This required a major re-modularization of OpenGL support on all levels, from basic window-system specific interface to medium-level object-representation and top-level scene management. This new architecture allows seamless integration of external scene-graph libraries into the ROOT OpenGL viewer as well as inclusion of ROOT 3D scenes into external GUI and OpenGL-based 3D-rendering frameworks. Scene representation was removed from inside of the viewer, allowing scene-data to be shared among several viewers and providing for a natural implementation of multi-view canvas layouts. The object-graph traversal infrastructure allows free mixing of 3D and 2D-pad graphics and makes implementation of ROOT canvas in pure OpenGL possible. Scene-elements representing ROOT objects trigger automatic instantiation of user-provided rendering-objects based on the dictionary information and class-naming convention. Additionally, a finer, per-object control over scene-updates is available to the user, allowing overhead-free maintenance of dynamic 3D scenes and creation of complex real-time animations. User-input handling was modularized as well, making it easy to support application-specific scene navigation, selection handling and tool management.
Investigating non-Markovian dynamics of quantum open systems
NASA Astrophysics Data System (ADS)
Chen, Yusui
Quantum open system coupled to a non-Markovian environment has recently attracted widespread interest for its important applications in quantum information processing and quantum dissipative systems. New phenomena induced by the non-Markovian environment have been discovered in variety of research areas ranging from quantum optics, quantum decoherence to condensed matter physics. However, the study of the non-Markovian quantum open system is known a difficult problem due to its technical complexity in deriving the fundamental equation of motion and elusive conceptual issues involving non-equilibrium dynamics for a strong coupled environment. The main purpose of this thesis is to introduce several new techniques of solving the quantum open systems including a systematic approach to dealing with non-Markovian master equations from a generic quantum-state diffusion (QSD) equation. In the first part of this thesis, we briefly introduce the non-Markovian quantum-state diffusion approach, and illustrate some pronounced non-Markovian quantum effects through numerical investigation on a cavity-QED model. Then we extend the non-Markovian QSD theory to an interesting model where the environment has a hierarchical structure, and find out the exact non-Markovian QSD equation of this model system. We observe the generation of quantum entanglement due to the interplay between the non-Markovian environment and the cavity. In the second part, we show an innovative method to obtain the exact non-Markovian master equations for a set of generic quantum open systems based on the corresponding non-Markovian QSD equations. Multiple-qubit systems and multilevel systems are discussed in details as two typical examples. Particularly, we derive the exact master equation for a model consisting of a three-level atom coupled to an optical cavity and controlled by an external laser field. Additionally, we discuss in more general context the mathematical similarity between the multiple
Open systems dynamics for propagating quantum fields
NASA Astrophysics Data System (ADS)
Baragiola, Ben Quinn
In this dissertation, I explore interactions between matter and propagating light. The electromagnetic field is modeled as a Markovian reservoir of quantum harmonic oscillators successively streaming past a quantum system. Each weak and fleeting interaction entangles the light and the system, and the light continues its course. In the context of quantum tomography or metrology one attempts, using measure- ments of the light, to extract information about the quantum state of the system. An inevitable consequence of these measurements is a disturbance of the system's quantum state. These ideas focus on the system and regard the light as ancillary. It serves its purpose as a probe or as a mechanism to generate interesting dynamics or system states but is eventually traced out, leaving the reduced quantum state of the system as the primary mathematical subject. What, then, when the state of light itself harbors intrinsic self-entanglement? One such set of states, those where a traveling wave packet is prepared with a defi- nite number of photons, is a focal point of this dissertation. These N-photon states are ideal candidates as couriers in quantum information processing device. In con- trast to quasi-classical states, such as coherent or thermal fields, N-photon states possess temporal mode entanglement, and local interactions in time have nonlocal consequences. The reduced state of a system probed by an N-photon state evolves in a non-Markovian way, and to describe its dynamics one is obliged to keep track of the field's evolution. I present a method to do this for an arbitrary quantum system using a set of coupled master equations. Many models set aside spatial degrees of freedom as an unnecessary complicating factor. By doing so the precision of predictions is limited. Consider a ensemble of cold, trapped atomic spins dispersively probed by a paraxial laser beam. Atom-light coupling across the ensemble is spatially inhomogeneous as is the radiation pattern of
Disk magnetocumulative generator with an explosive opening switch
NASA Astrophysics Data System (ADS)
Demidov, V. A.; Boriskin, A. S.; Kazakov, S. A.; Tatsenko, O. M.; Vlasov, Yu. V.; Shapovalov, E. V.; Romanov, A. P.; Filippov, A. V.; Golosov, S. N.; Moiseenko, A. N.; Schetnikov, E. I.; Yanenko, V. A.; Kutumov, S. V.; Kazakova, N. R.; Volodchenkov, S. I.; Grushko, V. V.; Nikolaev, N. I.; Yusupov, R. R.; Galanova, S. V.; Sevastyanov, A. S.; Kostin, V. V.; Pikar', A. S.; Korolev, P. V.; Kruchinin, V. A.; Parfenov, A. D.; Toropova, T. A.
2015-01-01
This paper presents the results of tests of a facility based on a ten-element disk magnetocumulative generator and an explosive opening switch. A current of 10 MA with a characteristic rise time of ≈0.5 µs was obtained by breaking a circuit with a current of 18 MA in a load with an inductance of 16 nH, which is equivalent to the inductance of the chamber with a multiwire liner.
Dynamical generation of the top quark mass
NASA Astrophysics Data System (ADS)
Popovic, Marko Berislav
2002-09-01
I study new physics theories in which the observed mass of the heaviest elementary particle, the top quark, is a result of a dynamical mechanism at the subatomic level. The same mechanism needs to explain the transition of the effective physical description at the largest space-time scales to that at smaller scales. This large-scale description is characterized by non-zero masses for most of the elementary particles and the existence of the familiar electromagnetic interactions. The description at smaller space-time scales is characterized by the presence of a richer set of fundamental interactions, including weak and hypercharge interactions, as well as no masses for the particles. As a minimal consequence of this transition, particle theories commonly predict the existence of a still unobserved particle, called the Higgs, at the largest scales. New physics considered in this thesis includes the following: (1) Models with new fundamental interactions that select the top quark and give an exclusive role to its dynamical mass generation mechanism. I propose one such model, discuss current experimental constraints, and suggest future tests of this idea. (2) Models with new spin one-half particles, not sensitive to the weak interactions, that mix with ordinary particles, including the top quark. I discuss the phenomenology, i.e., analyze data from particle colliders, and set limits on the parameters of the models. (3) Models with new spin one-half particles, sensitive to the weak interactions, that mix with ordinary particles. I propose the model structure, discuss some of its phenomenology, and suggest further tests of this idea at linear particle accelerators. Finally, I analyze the connection between the Higgs mass (m H) and the space-time scale at which the above-mentioned transition occurs. Without introducing new physics at the smallest scales, I show that due to the very large top mass, the standard description with the Higgs particle fails at small scales
Digital computer program for generating dynamic turbofan engine models (DIGTEM)
NASA Technical Reports Server (NTRS)
Daniele, C. J.; Krosel, S. M.; Szuch, J. R.; Westerkamp, E. J.
1983-01-01
This report describes DIGTEM, a digital computer program that simulates two spool, two-stream turbofan engines. The turbofan engine model in DIGTEM contains steady-state performance maps for all of the components and has control volumes where continuity and energy balances are maintained. Rotor dynamics and duct momentum dynamics are also included. Altogether there are 16 state variables and state equations. DIGTEM features a backward-differnce integration scheme for integrating stiff systems. It trims the model equations to match a prescribed design point by calculating correction coefficients that balance out the dynamic equations. It uses the same coefficients at off-design points and iterates to a balanced engine condition. Transients can also be run. They are generated by defining controls as a function of time (open-loop control) in a user-written subroutine (TMRSP). DIGTEM has run on the IBM 370/3033 computer using implicit integration with time steps ranging from 1.0 msec to 1.0 sec. DIGTEM is generalized in the aerothermodynamic treatment of components.
Intrinsic and dynamically generated scalar meson states
NASA Astrophysics Data System (ADS)
Shakin, C. M.; Wang, Huangsheng
2001-01-01
Recent work by Maltman has given us confidence that our assignment of scalar meson states to various nonets based upon our generalized Nambu-Jona-Lasinio (NJL) model is correct. [For example, in our model the a0(980) and the f0(980) are in the same nonet as the K*0(1430).] In this work we make use of our model to provide a precise definition of ``preexisting'' resonances and ``dynamically generated'' resonances when considering various scalar mesons. [This distinction has been noted by Meissner in his characterization of the f0(400-1200) as nonpreexisting.] We define preexisting (or intrinsic) resonances as those that appear as singularities of the qq¯ T matrix and are in correspondence with qq¯ states bound in the confining field. [Additional singularities may be found when studying the T matrices describing π-π or π-K scattering, for example. Such features may be seen to arise, in part, from t-channel and u-channel ρ exchange in the case of π-π scattering, leading to the introduction of the σ(500-600). In addition, threshold effects in the qq¯ T matrix can give rise to significant broad cross section enhancements. The latter is, in part, responsible for the introduction of the κ(900) in a study of π-K scattering, for example.] We suggest that it is only the intrinsic resonances which correspond to qq¯ quark-model states, and it is only the intrinsic states that are to be used to form quark-model qq¯ nonets of states. [While the κ(900) and σ(500-600) could be placed in a nonet of dynamically generated states, it is unclear whether there is evidence that requires the introduction of other members of such a nonet.] In this work we show how the phenomena related to the introduction of the σ(500-600) and the κ(900) are generated in studies of π-π and π-K scattering, making use of our generalized Nambu-Jona-Lasinio model. We also calculate the decay constants for the a0 and K*0 mesons and compare our results with those obtained by Maltman. We find
NASA Astrophysics Data System (ADS)
Collis, Scott; helmus, Jonathan; Kotamarthi, Rao; Wang, Jiali; Feng, Yan; Ghate, Virendra
2016-04-01
In order to assess infrastructure resilience to climate change in urban centers, climate model output is needed at spatial resolutions required for urban planning. This is most commonly achieved using either empirical or dynamic downscaling at present. The utility of these downscaling methods for assessments depends on having estimates of biases in the models estimate climate variables and their extremes, surface temperature and precipitation as an example, developed using historical data sets. Since precipitation is a multi-scale stochastic process direct comparison with observations is challenging and even modern data sets work at scales too coarse to capture extreme events. Gauge data requires a direct hit by a storm to see the highest rain rates, often leading to an underestimation in the 1-100 year rainfall. This is exacerbated by phenomena such as training that can cause very high gradients in accumulation. This presentation details a long-term (multi-year) study of precipitation derived from open data from the NOAA Next-Generation Radar (NEXRAD) network. Two locations are studied; Portland, Maine, location for a pilot study conducted by the US Department of Homeland Security's on regional resilience to climate change and the Southern Great Plains of Oklahoma, home to the Department of Energy's ARM program. Both are located within 40km of a NEXRAD radar allowing retrievals of rainfall rates on the order of one kilometer using the Python-ARM Radar Toolkit (Py-ART). Both the diurnal and season cycle of precipitation is studied and compared to WRF dynamically downscaled precipitation rates. This project makes heavy use of open source community tools such as project Jupyter and the Scientific Python ecosystem to manage and process 10's of TB of data on midrange cluster infrastructure. Both the meteorological aspects and the data infrastructure and architecture will be discussed.
Quantum-gravity induced Lorentz violation and dynamical mass generation
Mavromatos, Nick E.
2011-01-15
In the eprint by Jean Alexandre [arXiv:1009.5834], a minimal extension of (3+1)-dimensional quantum electrodynamics has been proposed, which includes Lorentz violation (LV) in the form of higher-(spatial)-derivative isotropic terms in the gauge sector, suppressed by a mass scale M. The model can lead to dynamical mass generation for charged fermions. In this article, I elaborate further on this idea and I attempt to connect it to specific quantum-gravity models, inspired from string/brane theory. Specifically, in the first part of the article, I comment briefly on the gauge dependence of the dynamical mass generation in the approximations of J. Alexandre [arXiv:1009.5834.], and I propose a possible avenue for obtaining the true gauge-parameter-independent value of the mass by means of pinch technique argumentations. In the second part of the work, I embed the LV QED model into multibrane world scenarios with a view to provide a geometrical way of enhancing the dynamical mass to phenomenologically realistic values by means of bulk warp metric factors, in an (inverse) Randall-Sundrum hierarchy. Finally, in the third part of this paper, I demonstrate that such Lorentz-violating QED models may represent parts of a low-energy effective action (of Finsler-Born-Infeld type) of open strings propagating in quantum D0-particle stochastic space-time foam backgrounds, which are viewed as consistent quantum-gravity configurations. To capture correctly the quantum-fluctuating nature of the foam background, I replace the D0-recoil-velocity parts of this action by appropriate gradient operators in three-space, keeping the photon field part intact. This is consistent with the summation over world-sheet genera in the first-quantized string approach. I identify a class of quantum orderings which leads to the LV QED action of J. Alexandre, arXiv:1009.5834. In this way I argue, following the logic in that work, that the D-foam can lead to dynamically generated masses for charged
Kyoda, Koji; Tohsato, Yukako; Ho, Kenneth H. L.; Onami, Shuichi
2015-01-01
Motivation: Recent progress in live-cell imaging and modeling techniques has resulted in generation of a large amount of quantitative data (from experimental measurements and computer simulations) on spatiotemporal dynamics of biological objects such as molecules, cells and organisms. Although many research groups have independently dedicated their efforts to developing software tools for visualizing and analyzing these data, these tools are often not compatible with each other because of different data formats. Results: We developed an open unified format, Biological Dynamics Markup Language (BDML; current version: 0.2), which provides a basic framework for representing quantitative biological dynamics data for objects ranging from molecules to cells to organisms. BDML is based on Extensible Markup Language (XML). Its advantages are machine and human readability and extensibility. BDML will improve the efficiency of development and evaluation of software tools for data visualization and analysis. Availability and implementation: A specification and a schema file for BDML are freely available online at http://ssbd.qbic.riken.jp/bdml/. Contact: sonami@riken.jp Supplementary Information: Supplementary data are available at Bioinformatics online. PMID:25414366
Dynamics of open bosonic quantum systems in coherent state representation
Dalvit, D. A. R.; Berman, G. P.; Vishik, M.
2006-01-15
We consider the problem of decoherence and relaxation of open bosonic quantum systems from a perspective alternative to the standard master equation or quantum trajectories approaches. Our method is based on the dynamics of expectation values of observables evaluated in a coherent state representation. We examine a model of a quantum nonlinear oscillator with a density-density interaction with a collection of environmental oscillators at finite temperature. We derive the exact solution for dynamics of observables and demonstrate a consistent perturbation approach.
Glucans monomer-exchange dynamics as an open chemical network
NASA Astrophysics Data System (ADS)
Rao, Riccardo; Lacoste, David; Esposito, Massimiliano
2015-12-01
We describe the oligosaccharides-exchange dynamics performed by the so-called D-enzymes on polysaccharides. To mimic physiological conditions, we treat this process as an open chemical network by assuming some of the polymer concentrations fixed (chemostatting). We show that three different long-time behaviors may ensue: equilibrium states, nonequilibrium steady states, and continuous growth states. We dynamically and thermodynamically characterize these states and emphasize the crucial role of conservation laws in identifying the chemostatting conditions inducing them.
Dynamics of an Open System for Repeated Harmonic Perturbation
NASA Astrophysics Data System (ADS)
Tamura, Hiroshi; Zagrebnov, Valentin A.
2016-05-01
We use the Kossakowski-Lindblad-Davies formalism to study an open dynamical system defined as Markovian extension of the one-mode quantum resonator S, perturbed by repeated harmonic interaction with a chain of multi-level harmonic atoms C. The long-time asymptotic behaviour and correlations of various subsystems of the system S + C are treated in the framework of the W^*-dynamical system approach.
Glucans monomer-exchange dynamics as an open chemical network
Rao, Riccardo Esposito, Massimiliano; Lacoste, David
2015-12-28
We describe the oligosaccharides-exchange dynamics performed by the so-called D-enzymes on polysaccharides. To mimic physiological conditions, we treat this process as an open chemical network by assuming some of the polymer concentrations fixed (chemostatting). We show that three different long-time behaviors may ensue: equilibrium states, nonequilibrium steady states, and continuous growth states. We dynamically and thermodynamically characterize these states and emphasize the crucial role of conservation laws in identifying the chemostatting conditions inducing them.
Coarse grained open system quantum dynamics
Thanopulos, Ioannis; Brumer, Paul; Shapiro, Moshe
2008-11-21
We show that the quantum dynamics of a system comprised of a subspace Q coupled to a larger subspace P can be recast as a reduced set of 'coarse grained' ordinary differential equations with constant coefficients. These equations can be solved by a single diagonalization of a general complex matrix. The method makes no assumptions about the strength of the couplings between the Q and the P subspaces, nor is there any limitation on the initial population in P. The utility of the method is demonstrated via computations in three following areas: molecular compounds, photonic materials, and condensed phases.
Generating optimal control simulations of musculoskeletal movement using OpenSim and MATLAB
Lee, Leng-Feng
2016-01-01
Computer modeling, simulation and optimization are powerful tools that have seen increased use in biomechanics research. Dynamic optimizations can be categorized as either data-tracking or predictive problems. The data-tracking approach has been used extensively to address human movement problems of clinical relevance. The predictive approach also holds great promise, but has seen limited use in clinical applications. Enhanced software tools would facilitate the application of predictive musculoskeletal simulations to clinically-relevant research. The open-source software OpenSim provides tools for generating tracking simulations but not predictive simulations. However, OpenSim includes an extensive application programming interface that permits extending its capabilities with scripting languages such as MATLAB. In the work presented here, we combine the computational tools provided by MATLAB with the musculoskeletal modeling capabilities of OpenSim to create a framework for generating predictive simulations of musculoskeletal movement based on direct collocation optimal control techniques. In many cases, the direct collocation approach can be used to solve optimal control problems considerably faster than traditional shooting methods. Cyclical and discrete movement problems were solved using a simple 1 degree of freedom musculoskeletal model and a model of the human lower limb, respectively. The problems could be solved in reasonable amounts of time (several seconds to 1–2 hours) using the open-source IPOPT solver. The problems could also be solved using the fmincon solver that is included with MATLAB, but the computation times were excessively long for all but the smallest of problems. The performance advantage for IPOPT was derived primarily by exploiting sparsity in the constraints Jacobian. The framework presented here provides a powerful and flexible approach for generating optimal control simulations of musculoskeletal movement using OpenSim and MATLAB
Generating optimal control simulations of musculoskeletal movement using OpenSim and MATLAB.
Lee, Leng-Feng; Umberger, Brian R
2016-01-01
Computer modeling, simulation and optimization are powerful tools that have seen increased use in biomechanics research. Dynamic optimizations can be categorized as either data-tracking or predictive problems. The data-tracking approach has been used extensively to address human movement problems of clinical relevance. The predictive approach also holds great promise, but has seen limited use in clinical applications. Enhanced software tools would facilitate the application of predictive musculoskeletal simulations to clinically-relevant research. The open-source software OpenSim provides tools for generating tracking simulations but not predictive simulations. However, OpenSim includes an extensive application programming interface that permits extending its capabilities with scripting languages such as MATLAB. In the work presented here, we combine the computational tools provided by MATLAB with the musculoskeletal modeling capabilities of OpenSim to create a framework for generating predictive simulations of musculoskeletal movement based on direct collocation optimal control techniques. In many cases, the direct collocation approach can be used to solve optimal control problems considerably faster than traditional shooting methods. Cyclical and discrete movement problems were solved using a simple 1 degree of freedom musculoskeletal model and a model of the human lower limb, respectively. The problems could be solved in reasonable amounts of time (several seconds to 1-2 hours) using the open-source IPOPT solver. The problems could also be solved using the fmincon solver that is included with MATLAB, but the computation times were excessively long for all but the smallest of problems. The performance advantage for IPOPT was derived primarily by exploiting sparsity in the constraints Jacobian. The framework presented here provides a powerful and flexible approach for generating optimal control simulations of musculoskeletal movement using OpenSim and MATLAB. This
Relativistic Quantum Metrology in Open System Dynamics
Tian, Zehua; Wang, Jieci; Fan, Heng; Jing, Jiliang
2015-01-01
Quantum metrology studies the ultimate limit of precision in estimating a physical quantity if quantum strategies are exploited. Here we investigate the evolution of a two-level atom as a detector which interacts with a massless scalar field using the master equation approach for open quantum system. We employ local quantum estimation theory to estimate the Unruh temperature when probed by a uniformly accelerated detector in the Minkowski vacuum. In particular, we evaluate the Fisher information (FI) for population measurement, maximize its value over all possible detector preparations and evolution times, and compare its behavior with that of the quantum Fisher information (QFI). We find that the optimal precision of estimation is achieved when the detector evolves for a long enough time. Furthermore, we find that in this case the FI for population measurement is independent of initial preparations of the detector and is exactly equal to the QFI, which means that population measurement is optimal. This result demonstrates that the achievement of the ultimate bound of precision imposed by quantum mechanics is possible. Finally, we note that the same configuration is also available to the maximum of the QFI itself. PMID:25609187
Properties of earthquakes generated by fault dynamics
NASA Technical Reports Server (NTRS)
Carlson, J. M.; Langer, J. S.
1989-01-01
A model for fault dynamics consisting of a uniform chain of blocks and springs pulled slowly across a rough surface is presented. The only nonlinear element of the model is a slip-stick friction force between the blocks and the surface. It is found that this model gives rise to events of all sizes. The numerical evaluation of the distribution of earthquake magnitudes results in a power-law spectrum similar to what is observed in nature. Like certain other dissipative dynamical systems, the observed large fluctuations in earthquake magnitude persist because the system is in a state of marginal stability.
Dynamical and thermodynamical control of Open Quantum Walks
NASA Astrophysics Data System (ADS)
Petruccione, Francesco; Sinayskiy, Ilya
2014-03-01
Over the last few years dynamical properties and limit distributions of Open Quantum Walks (OQWs), quantum walks driven by dissipation, have been intensely studied [S. Attal et. al. J. Stat. Phys. 147, Issue 4, 832 (2012)]. For some particular cases of OQWs central limit theorems have been proven [S. Attal, N. Guillotin, C. Sabot, ``Central Limit Theorems for Open Quantum Random Walks,'' to appear in Annales Henri Poincaré]. However, only recently the connection between the rich dynamical behavior of OQWs and the corresponding microscopic system-environment models has been established. The microscopic derivation of an OQW as a reduced system dynamics on a 2-nodes graph [I. Sinayskiy, F. Petruccione, Open Syst. Inf. Dyn. 20, 1340007 (2013)] and its generalization to arbitrary graphs allow to explain the dependance of the dynamical behavior of the OQW on the temperature and coupling to the environment. For thermal environments we observe Gaussian behaviour, whereas at zero temperature population trapping and ``soliton''-like behaviour are possible. Physical realizations of OQWs in quantum optical setups will be also presented. This work is based on research supported by the South African Research Chair Initiative of the Department of Science and Technology and National Research Foundation.
Dynamics and stability of wind turbine generators
NASA Technical Reports Server (NTRS)
Hinrichsen, E. N.; Nolan, P. J.
1981-01-01
Synchronous and induction generators are considered. A comparison is made between wind turbines, steam, and hydro units. The unusual phenomena associated with wind turbines are emphasized. The general control requirements are discussed, as well as various schemes for torsional damping such as speed sensitive stabilizer and blade pitch control. Integration between adjacent wind turbines in a wind farm is also considered.
Automation Framework for Flight Dynamics Products Generation
NASA Technical Reports Server (NTRS)
Wiegand, Robert E.; Esposito, Timothy C.; Watson, John S.; Jun, Linda; Shoan, Wendy; Matusow, Carla
2010-01-01
XFDS provides an easily adaptable automation platform. To date it has been used to support flight dynamics operations. It coordinates the execution of other applications such as Satellite TookKit, FreeFlyer, MATLAB, and Perl code. It provides a mechanism for passing messages among a collection of XFDS processes, and allows sending and receiving of GMSEC messages. A unified and consistent graphical user interface (GUI) is used for the various tools. Its automation configuration is stored in text files, and can be edited either directly or using the GUI.
Glucans monomer-exchange dynamics as an open chemical network.
Rao, Riccardo; Lacoste, David; Esposito, Massimiliano
2015-12-28
We describe the oligosaccharides-exchange dynamics performed by the so-called D-enzymes on polysaccharides. To mimic physiological conditions, we treat this process as an open chemical network by assuming some of the polymer concentrations fixed (chemostatting). We show that three different long-time behaviors may ensue: equilibrium states, nonequilibrium steady states, and continuous growth states. We dynamically and thermodynamically characterize these states and emphasize the crucial role of conservation laws in identifying the chemostatting conditions inducing them. PMID:26723707
Dynamical and thermodynamical control of open quantum Brownian motion
NASA Astrophysics Data System (ADS)
Petruccione, Francesco; Sinayskiy, Ilya
Open quantum Brownian motion was introduced as a new type of quantum Brownian motion for Brownian particles with internal quantum degrees of freedom. Recently, an example of the microscopic derivation of open quantum Brownian motion has been presented [I. Sinayskiy and F. Petruccione, Phys. Scr. T165, 014017 (2015)]. The microscopic derivation allows to relate the dynamical properties of open Quantum Brownian motion and the thermodynamical properties of the environment. In the present work, we study the possibility of control of the external degrees of freedom of the ''walker'' (position) by manipulating the internal one, e.g. spin, polarization, occupation numbers. In the particular example of the known microscopic derivation the connection between dynamics of the ''walker'' and thermodynamical parameters of the system is established. For the system of open Brownian walkers coupled to the same environment controllable creation of quantum correlations is investigated. This work is based upon research supported by the South African Research Chair Initiative of the Department of Science and Technology and National Research Foundation.
Dynamical gauge effects in an open quantum network
NASA Astrophysics Data System (ADS)
Zhao, Jianshi; Price, Craig; Liu, Qi; Gemelke, Nathan
2016-05-01
We describe new experimental techniques for simulation of high-energy field theories based on an analogy between open thermodynamic systems and effective dynamical gauge-fields following SU(2) × U(1) Yang-Mills models. By coupling near-resonant laser-modes to atoms moving in a disordered optical environment, we create an open system which exhibits a non-equilibrium phase transition between two steady-state behaviors, exhibiting scale-invariant behavior near the transition. By measuring transport of atoms through the disordered network, we observe two distinct scaling behaviors, corresponding to the classical and quantum limits for the dynamical gauge field. This behavior is loosely analogous to dynamical gauge effects in quantum chromodynamics, and can mapped onto generalized open problems in theoretical understanding of quantized non-Abelian gauge theories. Additional, the scaling behavior can be understood from the geometric structure of the gauge potential and linked to the measure of information in the local disordered potential, reflecting an underlying holographic principle. We acknowledge support from NSF Award No.1068570, and the Charles E. Kaufman Foundation.
Can Generating Representations Enhance Learning with Dynamic Visualizations?
ERIC Educational Resources Information Center
Zhang, Zhihui Helen; Linn, Marcia C.
2011-01-01
This study explores the impact of asking middle school students to generate drawings of their ideas about chemical reactions on integrated understanding. Students explored atomic interactions during hydrogen combustion using a dynamic visualization. The generation group drew their ideas about how the reaction takes place at the molecular level.…
Fluid dynamic aspects of jet noise generation
NASA Technical Reports Server (NTRS)
1974-01-01
The location of the noise sources within jet flows, their relative importance to the overall radiated field, and the mechanisms by which noise generation occurs, are studied by detailed measurements of the level and spectral composition of the radiated sound in the far field. Directional microphones are used to isolate the contribution to the radiated sound of small regions of the flow, and for cross-correlation between the radiated acoustic field and either the velocity fluctuations or the pressure fluctuations in the source field. Acquired data demonstrate the supersonic convection of the acoustic field and the resulting limited upstream influence of the signal source, as well as a possible increase of signal strength as it propagates toward the centerline of the flow.
Generating functionals for autonomous latching dynamics in attractor relict networks
Linkerhand, Mathias; Gros, Claudius
2013-01-01
Coupling local, slowly adapting variables to an attractor network allows to destabilize all attractors, turning them into attractor ruins. The resulting attractor relict network may show ongoing autonomous latching dynamics. We propose to use two generating functionals for the construction of attractor relict networks, a Hopfield energy functional generating a neural attractor network and a functional based on information-theoretical principles, encoding the information content of the neural firing statistics, which induces latching transition from one transiently stable attractor ruin to the next. We investigate the influence of stress, in terms of conflicting optimization targets, on the resulting dynamics. Objective function stress is absent when the target level for the mean of neural activities is identical for the two generating functionals and the resulting latching dynamics is then found to be regular. Objective function stress is present when the respective target activity levels differ, inducing intermittent bursting latching dynamics. PMID:23784373
Dynamics of Micro-Plasmas Generated in Noble Gases by Strong-Field Laser Pulses
NASA Astrophysics Data System (ADS)
Romanov, Dmitri A.; Compton, Ryan; Filin, Alex; Levis, Robert J.
2010-03-01
The ultrafast dynamics of micro-plasmas generated by an ˜80 fs laser pulse in noble gases has been investigated using four-wave mixing (FWM). The evolution patterns of the FWM signal are indicative of the gas species and ambient conditions. The signal is observed to reach higher intensity levels faster for Xe, with progressively lower scattering intensity and longer time dynamics for the noble gas series Xe, Kr, Ar, Ne, and He. The theoretical model for interpreting this temporal dynamics is based on initial tunnel ionization followed by electron impact ionization cooling. The model reproduces well the measured degree of ionization in atmospheric-pressure laser-induced plasmas and predicts quantitatively the intensity of four-wave mixing as a function of time for the series of five noble gases. The model also predicts the dynamics as a function of pump laser intensity and gas pressure. The findings open the way for effective control of micro-plasma dynamics.
Dynamic properties of high structural integrity auxetic open cell foam
NASA Astrophysics Data System (ADS)
Scarpa, F.; Ciffo, L. G.; Yates, J. R.
2004-02-01
This paper illustrates various dynamic characteristics of open cell compliant polyurethane foam with auxetic (negative Poisson's ratio) behaviour. The foam is obtained from off-the-shelf open cell polyurethane grey foam with a manufacturing process based on mechanical deformation on a mould in a temperature-controlled oven. The Poisson's ratio is measured with an image processing technique based on edge detection with wavelet methods. Foam samples have been tested in a viscoelastic analyser tensile test machine to determine the Young's modulus and loss factor for small dynamic strains. The same samples have also been tested in an acoustic impedance tube to measure acoustic absorption and specific acoustic resistance and reactance with a transmissibility technique. Another set of tests has been set up on a cam plastometer machine for constant strain rate dynamic crushing analysis. All the tests have been carried out on auxetic and normal foam samples to provide a comparison between the two types of cellular solids. The results from the experimental tests are discussed and interpreted using microstructure models for cellular materials existing in the literature. The negative Poisson's ratio foam presented in this paper shows an overall superiority regarding damping and acoustic properties compared to the original conventional foam. Its dynamic crushing performance is also significantly superior to the normal foam, suggesting a possible use in structural integrity compliant elements.
Open boundary molecular dynamics of sheared star-polymer melts.
Sablić, Jurij; Praprotnik, Matej; Delgado-Buscalioni, Rafael
2016-02-28
Open boundary molecular dynamics (OBMD) simulations of a sheared star polymer melt under isothermal conditions are performed to study the rheology and molecular structure of the melt under a fixed normal load. Comparison is made with the standard molecular dynamics (MD) in periodic (closed) boxes at a fixed shear rate (using the SLLOD dynamics). The OBMD system exchanges mass and momentum with adjacent reservoirs (buffers) where the external pressure tensor is imposed. Insertion of molecules in the buffers is made feasible by implementing there a low resolution model (blob-molecules with soft effective interactions) and then using the adaptive resolution scheme (AdResS) to connect with the bulk MD. Straining with increasing shear stress induces melt expansion and a significantly different redistribution of pressure compared with the closed case. In the open sample, the shear viscosity is also a bit lowered but more stable against the viscous heating. At a given Weissenberg number, molecular deformations and material properties (recoverable shear strain and normal stress ratio) are found to be similar in both setups. We also study the modelling effect of normal and tangential friction between monomers implemented in a dissipative particle dynamics (DPD) thermostat. Interestingly, the tangential friction substantially enhances the elastic response of the melt due to a reduction of the kinetic stress viscous contribution. PMID:26820315
Dynamical mass generation in QED with weak magnetic fields
Ayala, A.; Rojas, E.; Bashir, A.; Raya, A.
2006-09-25
We study the dynamical generation of masses for fundamental fermions in quenched quantum electrodynamics in the presence of magnetic fields using Schwinger-Dyson equations. We show that, contrary to the case where the magnetic field is strong, in the weak field limit eB << m(0)2, where m(0) is the value of the dynamically generated mass in the absence of the magnetic field, masses are generated above a critical value of the coupling and that this value is the same as in the case with no magnetic field. We carry out a numerical analysis to study the magnetic field dependence of the mass function above critical coupling and show that in this regime the dynamically generated mass and the chiral condensate for the lowest Landau level increase proportionally to (eB)2.
Modeling community population dynamics with the open-source language R.
Green, Robin; Shou, Wenying
2014-01-01
The ability to explain biological phenomena with mathematics and to generate predictions from mathematical models is critical for understanding and controlling natural systems. Concurrently, the rise in open-source software has greatly increased the ease at which researchers can implement their own mathematical models. With a reasonably sound understanding of mathematics and programming skills, a researcher can quickly and easily use such tools for their own work. The purpose of this chapter is to expose the reader to one such tool, the open-source programming language R, and to demonstrate its practical application to studying population dynamics. We use the Lotka-Volterra predator-prey dynamics as an example. PMID:24838889
OpenSim: open-source software to create and analyze dynamic simulations of movement.
Delp, Scott L; Anderson, Frank C; Arnold, Allison S; Loan, Peter; Habib, Ayman; John, Chand T; Guendelman, Eran; Thelen, Darryl G
2007-11-01
Dynamic simulations of movement allow one to study neuromuscular coordination, analyze athletic performance, and estimate internal loading of the musculoskeletal system. Simulations can also be used to identify the sources of pathological movement and establish a scientific basis for treatment planning. We have developed a freely available, open-source software system (OpenSim) that lets users develop models of musculoskeletal structures and create dynamic simulations of a wide variety of movements. We are using this system to simulate the dynamics of individuals with pathological gait and to explore the biomechanical effects of treatments. OpenSim provides a platform on which the biomechanics community can build a library of simulations that can be exchanged, tested, analyzed, and improved through a multi-institutional collaboration. Developing software that enables a concerted effort from many investigators poses technical and sociological challenges. Meeting those challenges will accelerate the discovery of principles that govern movement control and improve treatments for individuals with movement pathologies. PMID:18018689
Integrating extended MHD and kinetic physics into the next-generation OpenGGCM
NASA Astrophysics Data System (ADS)
Germaschewski, K.; Wang, L.; Maynard, K. R. M.; Raeder, J.
2015-12-01
Going beyond one-fluid MHD is crucial to properly model the ion- and electron-scale reconnection physics in collisionless plasmas, as present in Earth's geospace environment. This presentation introduces the next-generation OpenGGCM, based on J.~Raeder's well-known global magnetospheric model. OpenGGCM has been modularized using the libMRC framework, so that components can easily be exchanged. For example, the MHD solver can be replaced by using a coupled version of the multi-fluid moment code Gkeyll, that handles multiple species and integrates kinetic effects, e.g., a full pressure tensor. We have also added the option to couple OpenGGCM to the widely used ATHENA code. Similarly, there are options for inner magnetosphere and ionosphere models. Mesh refinement is available in the new version, enabling the use of a computational grid that puts very high resolution at the reconnection current sheets at the dayside magnetopause and in the magnetotail while saving computational effort using a coarser resolution in regions that have no small-scale dynamics. Mesh refinement is implemented as a number of sparse-matrix multiplications to fill ghost cells, and to correct fluxes and electric fields. It supports exact flux conservation for the cell-centered fluid quantities and the staggered Yee grid for the electromagnetic fields, maintaining the magnetic field divergence-free to machine precision. We will present computational tests and show applications of the next-generation OpenGGCM to simulations of reconnection at Ganymede and at Earth's dayside magnetopause.
NASA Technical Reports Server (NTRS)
Bolt, P. A.; Hess, R. W.; Davis, W. T.
1983-01-01
A portable dynamic pressure generator was developed to meet the requirements of determining the dynamic sensitivities of in situ pressure transducers at low frequencies. The device is designed to operate in a frequency range of 0 to 100 Hz, although it was only tested up to 30 Hz, and to generate dynamic pressures up to 13.8 kPa (2 psi). A description of the operating characteristics and instrumentation used for pressure, frequency, and displacement measurements is given. The pressure generator was used to statically and dynamically calibrate transducers. Test results demonstrated that a difference an exist between the static and dynamic sensitivity of a transducer, confirming the need for dynamic calibrations of in situ pressure transducers.
Drożdż, Wojciech; Kołodziejski, Michał; Markiewicz, Grzegorz; Jenczak, Anna; Stefankiewicz, Artur R.
2015-01-01
We describe here the generation of new donor-acceptor disulfide architectures obtained in aqueous solution at physiological pH. The application of a dynamic combinatorial chemistry approach allowed us to generate a large number of new disulfide macrocyclic architectures together with a new type of [2]catenanes consisting of four distinct components. Up to fifteen types of structurally-distinct dynamic architectures have been generated through one-pot disulfide exchange reactions between four thiol-functionalized aqueous components. The distribution of disulfide products formed was found to be strongly dependent on the structural features of the thiol components employed. This work not only constitutes a success in the synthesis of topologically- and morphologically-complex targets, but it may also open new horizons for the use of this methodology in the construction of molecular machines. PMID:26193265
Dynamic Loads Generation for Multi-Point Vibration Excitation Problems
NASA Technical Reports Server (NTRS)
Shen, Lawrence
2011-01-01
A random-force method has been developed to predict dynamic loads produced by rocket-engine random vibrations for new rocket-engine designs. The method develops random forces at multiple excitation points based on random vibration environments scaled from accelerometer data obtained during hot-fire tests of existing rocket engines. This random-force method applies random forces to the model and creates expected dynamic response in a manner that simulates the way the operating engine applies self-generated random vibration forces (random pressure acting on an area) with the resulting responses that we measure with accelerometers. This innovation includes the methodology (implementation sequence), the computer code, two methods to generate the random-force vibration spectra, and two methods to reduce some of the inherent conservatism in the dynamic loads. This methodology would be implemented to generate the random-force spectra at excitation nodes without requiring the use of artificial boundary conditions in a finite element model. More accurate random dynamic loads than those predicted by current industry methods can then be generated using the random force spectra. The scaling method used to develop the initial power spectral density (PSD) environments for deriving the random forces for the rocket engine case is based on the Barrett Criteria developed at Marshall Space Flight Center in 1963. This invention approach can be applied in the aerospace, automotive, and other industries to obtain reliable dynamic loads and responses from a finite element model for any structure subject to multipoint random vibration excitations.
Ehrenfest approach to open double-well dynamics.
Choi, Stephen; Onofrio, Roberto; Sundaram, Bala
2015-10-01
We consider an Ehrenfest approximation for a particle in a double-well potential in the presence of an external environment schematized as a finite resource heat bath. This allows us to explore how the limitations in the applicability of Ehrenfest dynamics to nonlinear systems are modified in an open system setting. Within this framework, we have identified an environment-induced spontaneous symmetry breaking mechanism, and we argue that the Ehrenfest approximation becomes increasingly valid in the limit of strong coupling to the external reservoir, either in the form of an increasing number of oscillators or increasing temperature. The analysis also suggests a rather intuitive picture for the general phenomenon of quantum tunneling and its interplay with classical thermal activation processes, which may be of relevance in physical chemistry, ultracold atom physics, and fast-switching dynamics such as in superconducting digital electronics. PMID:26565304
Dynamical phase transition in the open Dicke model.
Klinder, Jens; Keßler, Hans; Wolke, Matthias; Mathey, Ludwig; Hemmerich, Andreas
2015-03-17
The Dicke model with a weak dissipation channel is realized by coupling a Bose-Einstein condensate to an optical cavity with ultranarrow bandwidth. We explore the dynamical critical properties of the Hepp-Lieb-Dicke phase transition by performing quenches across the phase boundary. We observe hysteresis in the transition between a homogeneous phase and a self-organized collective phase with an enclosed loop area showing power-law scaling with respect to the quench time, which suggests an interpretation within a general framework introduced by Kibble and Zurek. The observed hysteretic dynamics is well reproduced by numerically solving the mean-field equation derived from a generalized Dicke Hamiltonian. Our work promotes the understanding of nonequilibrium physics in open many-body systems with infinite range interactions. PMID:25733892
Dynamical phase transition in the open Dicke model
Klinder, Jens; Keßler, Hans; Wolke, Matthias; Mathey, Ludwig; Hemmerich, Andreas
2015-01-01
The Dicke model with a weak dissipation channel is realized by coupling a Bose–Einstein condensate to an optical cavity with ultranarrow bandwidth. We explore the dynamical critical properties of the Hepp–Lieb–Dicke phase transition by performing quenches across the phase boundary. We observe hysteresis in the transition between a homogeneous phase and a self-organized collective phase with an enclosed loop area showing power-law scaling with respect to the quench time, which suggests an interpretation within a general framework introduced by Kibble and Zurek. The observed hysteretic dynamics is well reproduced by numerically solving the mean-field equation derived from a generalized Dicke Hamiltonian. Our work promotes the understanding of nonequilibrium physics in open many-body systems with infinite range interactions. PMID:25733892
Development and Design of a Dynamic Multimedia Item Generation Mechanism
ERIC Educational Resources Information Center
Weng, Ting-Sheng
2012-01-01
This research applies multimedia technology to design a dynamic item generation method that can adaptively adjust the difficulty level of items according to the level of the testee. The method is based on interactive testing software developed by Flash Actionscript, and provides a testing solution for users by automatically distributing items of…
Designing Guidance for Interpreting Dynamic Visualizations: Generating versus Reading Explanations
ERIC Educational Resources Information Center
Ryoo, Kihyun; Linn, Marcia C.
2014-01-01
We compared designs of guidance to support students while interacting with dynamic visualizations of complex scientific phenomena in inquiry instruction. Three hundred thirty-two 7th-grade students were randomly assigned to either a reading or a generating condition and completed a web-based inquiry unit focusing on energy concepts in…
NASA Astrophysics Data System (ADS)
Guillaume, Benjamin; Moroni, Monica; Funiciello, Francesca; Martinod, Joseph; Faccenna, Claudio
2010-12-01
We present dynamically self-consistent mantle-scale laboratory models that have been conducted to improve our understanding of the influence of slab window opening on subduction dynamics, mantle flow and associated dynamic topography over geological time scales. The adopted setup consists of a two-layer linearly viscous system simulating the subduction of a fixed plate of silicone (lithosphere) under negative buoyancy in a viscous layer of glucose syrup (mantle). Our experimental setting is also characterized by a constant-width rectangular window located at the center of a laterally confined slab, modeling the case of the interaction of a trench-parallel spreading ridge with a wide subduction zone. We found that the opening of a slab window does not produce consistent changes of the geometry and the kinematics of the slab. On the contrary, slab-induced mantle circulation, quantified both in the vertical and horizontal sections using the Feature Tracking image analysis technique, is strongly modified. In particular, rollback subduction and the opening of the slab window generate a complex mantle circulation pattern characterized by the presence of poloidal and toroidal components, with the importance of each evolving according to kinematic stages. Mantle coming from the oceanic domain floods through the slab window, indenting the supra-slab mantle zone and producing its deformation without any mixing between mantle portions. The opening of the slab window and the upwelling of sub-slab mantle produce a regional-scale non-isostatic topographic uplift of the overriding plate that would correspond to values ranging between ca. 1 and 5 km in nature. Assuming that our modeling results can be representative of the natural behavior of subduction zones, we compared them to the tectonics and volcanism of the Patagonian subduction zone. We found that the anomalous backarc volcanism that has been developing since the middle Miocene could result from the lateral flow of sub
Dynamically generated flat-band phases in optical kagome lattices
NASA Astrophysics Data System (ADS)
Chern, Gia-Wei; Chien, Chih-Chun; Di Ventra, Massimiliano
2014-07-01
Motivated by recent advances in the realization of complex two-dimensional optical lattices, we investigate theoretically the quantum transport of ultracold fermions in an optical kagome lattice. In particular, we focus on its extensively degenerate localized states (flat band). By loading fermions in a partial region of the lattice and depleting the mobile atoms at the far boundary of the initially unoccupied region, we find a dynamically generated flat-band insulator, which is also a population-inverted state. We further show that inclusion of weak repulsion leads to a dynamical stripe phase for two-component fermions in a similar setup. Finally, by preparing a topological insulating state in a partially occupied kagome lattice, we find that the topological chiral current decays but exhibits an interesting oscillating dynamics during the nonequilibrium transport. Given the broad variety of lattice geometries supporting localized or topological states, our work suggests new possibilities for using geometrical effects and their dynamics in atomtronic devices.
Open microdroplet diluter for concentration-gradient generation
NASA Astrophysics Data System (ADS)
Nee Tan, Jue; Alan, Tuncay; Neild, Adrian
2014-08-01
The requirement of producing concentration gradients rapidly and controllably is essential in many biochemical applications. The use of microdroplets is advantageous as the droplets act as isolated open reaction vessels that are proficient in containing a variety of reagents. We present a concept of producing concentration gradients over an array of open wells, using a concentrated primary drop which, whilst in motion, merges with successive buffer droplets and, as a result, leaves behind droplets of different concentrations. The primary drop is positioned to slide down a 90° incline over several secondary drops, whereby merging, mixing, and detaching occurs within each well.
Force-generation and dynamic instability of microtubule bundles
Laan, Liedewij; Husson, Julien; Munteanu, E. Laura; Kerssemakers, Jacob W. J.; Dogterom, Marileen
2008-01-01
Individual dynamic microtubules can generate pushing or pulling forces when their growing or shrinking ends are in contact with cellular objects such as the cortex or chromosomes. These microtubules can operate in parallel bundles, for example when interacting with mitotic chromosomes. Here, we investigate the force-generating capabilities of a bundle of growing microtubules and study the effect that force has on the cooperative dynamics of such a bundle. We used an optical tweezers setup to study microtubule bundles growing against a microfabricated rigid barrier in vitro. We show that multiple microtubules can generate a pushing force that increases linearly with the number of microtubules present. In addition, the bundle can cooperatively switch to a shrinking state, due to a force-induced coupling of the dynamic instability of single microtubules. In the presence of GMPCPP, bundle catastrophes no longer occur, and high bundle forces are reached more effectively. We reproduce the observed behavior with a simple simulation of microtubule bundle dynamics that takes into account previously measured force effects on single microtubules. Using this simulation, we also show that a constant compressive force on a growing bundle leads to oscillations in bundle length that are of potential relevance for chromosome oscillations observed in living cells. PMID:18577596
Open architecture applied to next-generation weapons
NASA Astrophysics Data System (ADS)
Rose, Leo J.; Shaver, Jonathan; Young, Quinn; Christensen, Jacob
2014-06-01
The Air Force Research Laboratory (AFRL) has postulated a new weapons concept known as Flexible Weapons to define and develop technologies addressing a number of challenges. Initial studies on capability attributes of this concept have been conducted and AFRL plans to continue systems engineering studies to quantify metrics against which the value of capabilities can be assessed. An important aspect of Flexible Weapons is having a modular "plug-n-play" hardware and software solution, supported by an Open Architecture and Universal Armament Interface (UAI) common interfaces. The modular aspect of Flexible Weapons is a means to successfully achieving interoperability and composability at the weapon level. Interoperability allows for vendor competition, timely technology refresh, and avoids costs by ensuring standard interfaces widely supported in industry, rather than an interface unique to a particular vendor. Composability provides for the means to arrange an open end set of useful weapon systems configurations. The openness of Flexible Weapons is important because it broadens the set of computing technologies, software updates, and other technologies to be introduced into the weapon system, providing the warfighter with new capabilities at lower costs across the life cycle. One of the most critical steps in establishing a Modular, Open Systems Architecture (MOSA) for weapons is the validation of compliance with the standard.
Dynamic simulation of dual-speed wind turbine generation
Muljadi, E.; Butterfield, C.P.
1996-10-01
Induction generators have been used since the early development of utility-scale wind turbine generation. An induction generator is the generator of choice because of its ruggedness, and low cost. With an induction generator, the operating speed of the wind turbine is limited to a narrow range (almost constant speed). Dual- speed operation can be accomplished by using an induction generator with two different sets of winding configurations or by using two induction generators with two different rated speeds. With single- speed operation, the wind turbine operates at different power coefficients (Cp) as the wind speed varies. The operation at maximum Cp can occur only at a single wind speed. However, if the wind speed varies across a wider range, the operating Cp will vary significantly. Dual-speed operation has the advantage of enabling the wind turbine to operate at near maximum Cp over a wider range of wind-speeds. Thus, annual energy production can be increased. The dual-speed mode may generate less energy than a variable-speed mode; nevertheless, it offers an alternative to capture more energy than single-speed operation. In this paper, dual-speed operation of a wind turbine will be investigated. One type of control algorithm for dual- speed operation is proposed. Results from a dynamic simulation will be presented to show how the control algorithm works and how power, current and torque of the system vary as the wind turbine is exposed to varying wind speeds.
ERCOT's Dynamic Model of Wind Turbine Generators: Preprint
Muljadi, E.; Butterfield, C. P.; Conto, J.; Donoho, K.
2005-08-01
By the end of 2003, the total installed wind farm capacity in the Electric Reliability Council of Texas (ERCOT) system was approximately 1 gigawatt (GW) and the total in the United States was about 5 GW. As the number of wind turbines installed throughout the United States increases, there is a greater need for dynamic wind turbine generator models that can properly model entire power systems for different types of analysis. This paper describes the ERCOT dynamic models and simulations of a simple network with different types of wind turbine models currently available.
Open-system dynamics of entanglement: a key issues review.
Aolita, Leandro; de Melo, Fernando; Davidovich, Luiz
2015-04-01
One of the greatest challenges in the fields of quantum information processing and quantum technologies is the detailed coherent control over each and every constituent of quantum systems with an ever increasing number of particles. Within this endeavor, harnessing of many-body entanglement against the detrimental effects of the environment is a major pressing issue. Besides being an important concept from a fundamental standpoint, entanglement has been recognized as a crucial resource for quantum speed-ups or performance enhancements over classical methods. Understanding and controlling many-body entanglement in open systems may have strong implications in quantum computing, quantum simulations of many-body systems, secure quantum communication or cryptography, quantum metrology, our understanding of the quantum-to-classical transition, and other important questions of quantum foundations.In this paper we present an overview of recent theoretical and experimental efforts to underpin the dynamics of entanglement under the influence of noise. Entanglement is thus taken as a dynamic quantity on its own, and we survey how it evolves due to the unavoidable interaction of the entangled system with its surroundings. We analyze several scenarios, corresponding to different families of states and environments, which render a very rich diversity of dynamical behaviors.In contrast to single-particle quantities, like populations and coherences, which typically vanish only asymptotically in time, entanglement may disappear at a finite time. In addition, important classes of entanglement display an exponential decay with the number of particles when subject to local noise, which poses yet another threat to the already-challenging scaling of quantum technologies. Other classes, however, turn out to be extremely robust against local noise. Theoretical results and recent experiments regarding the difference between local and global decoherence are summarized. Control and
Solitary waves in twist-opening models of DNA dynamics
NASA Astrophysics Data System (ADS)
Gaeta, Giuseppe; Venier, Laura
2008-07-01
We analyze traveling solitary wave solutions in the Barbi-Cocco-Peyrard twist-opening model of nonlinear DNA dynamics. We identify conditions, involving an interplay of physical parameters and asymptotic behavior, for such solutions to exist, and provide first-order ordinary differential equations whose solutions give the required solitary waves; these are not solvable in analytical terms, but are easily integrated numerically. The conditions for existence of solitary waves are not satisfied for trivial asymptotic behavior and physical values of the parameters, i.e., the Barbi-Cocco-Peyrard model admits only solitary wave solutions that entail a global modification of the molecule; this is compared with the situation met in another recently formulated class of DNA models with two degrees of freedom per site.
DNA dynamics in aqueous solution: opening the double helix
NASA Technical Reports Server (NTRS)
Pohorille, A.; Ross, W. S.; Tinoco, I. Jr; MacElroy, R. D. (Principal Investigator)
1990-01-01
The opening of a DNA base pair is a simple reaction that is a prerequisite for replication, transcription, and other vital biological functions. Understanding the molecular mechanisms of biological reactions is crucial for predicting and, ultimately, controlling them. Realistic computer simulations of the reactions can provide the needed understanding. To model even the simplest reaction in aqueous solution requires hundreds of hours of supercomputing time. We have used molecular dynamics techniques to simulate fraying of the ends of a six base pair double strand of DNA, [TCGCGA]2, where the four bases of DNA are denoted by T (thymine), C (cytosine), G (guanine), and A (adenine), and to estimate the free energy barrier to this process. The calculations, in which the DNA was surrounded by 2,594 water molecules, required 50 hours of CRAY-2 CPU time for every simulated 100 picoseconds. A free energy barrier to fraying, which is mainly characterized by the movement of adenine away from thymine into aqueous environment, was estimated to be 4 kcal/mol. Another fraying pathway, which leads to stacking between terminal adenine and thymine, was also observed. These detailed pictures of the motions and energetics of DNA base pair opening in water are a first step toward understanding how DNA will interact with any molecule.
Thermofield dynamics extension of the open string field theory
NASA Astrophysics Data System (ADS)
Botta Cantcheff, M.; Scherer Santos, R. J.
2016-03-01
We study the application of the rules of thermofield dynamics (TFD) to the covariant formulation of open-string field theory. We extend the states space and fields according to the duplication rules of TFD and construct the corresponding classical action. The result is interpreted as a theory whose fields would encode the statistical information of open strings. The physical spectrum of the free theory is studied through the cohomology of the extended Becchi, Rouet, Stora and Tyutin (BRST) charge, and, as a result, we get new fields in the spectrum emerging by virtue of the quantum entanglement, and, noticeably, it presents degrees of freedom that could be identified as those of closed strings. We also show, however, that their appearing in the action is directly related to the choice of the inner product in the extended algebra, so that different sectors of fields could be eliminated from the theory by choosing that product conveniently. Finally, we study the extension of the three-vertex interaction and provide a simple prescription for it of which the results at tree level agree with those of the conventional theory.
Dynamical generation of maximally entangled states in two identical cavities
Alexanian, Moorad
2011-11-15
The generation of entanglement between two identical coupled cavities, each containing a single three-level atom, is studied when the cavities exchange two coherent photons and are in the N=2,4 manifolds, where N represents the maximum number of photons possible in either cavity. The atom-photon state of each cavity is described by a qutrit for N=2 and a five-dimensional qudit for N=4. However, the conservation of the total value of N for the interacting two-cavity system limits the total number of states to only 4 states for N=2 and 8 states for N=4, rather than the usual 9 for two qutrits and 25 for two five-dimensional qudits. In the N=2 manifold, two-qutrit states dynamically generate four maximally entangled Bell states from initially unentangled states. In the N=4 manifold, two-qudit states dynamically generate maximally entangled states involving three or four states. The generation of these maximally entangled states occurs rather rapidly for large hopping strengths. The cavities function as a storage of periodically generated maximally entangled states.
Pitti, Alexandre; Lungarella, Max; Kuniyoshi, Yasuo
2009-01-01
Pattern generators found in the spinal cord are no more seen as simple rhythmic oscillators for motion control. Indeed, they achieve flexible and dynamical coordination in interaction with the body and the environment dynamics giving to rise motor synergies. Discovering the mechanisms underlying the control of motor synergies constitutes an important research question not only for neuroscience but also for robotics: the motors coordination of high dimensional robotic systems is still a drawback and new control methods based on biological solutions may reduce their overall complexity. We propose to model the flexible combination of motor synergies in embodied systems via partial phase synchronization of distributed chaotic systems; for specific coupling strength, chaotic systems are able to phase synchronize their dynamics to the resonant frequencies of one external force. We take advantage of this property to explore and exploit the intrinsic dynamics of one specified embodied system. In two experiments with bipedal walkers, we show how motor synergies emerge when the controllers phase synchronize to the body's dynamics, entraining it to its intrinsic behavioral patterns. This stage is characterized by directed information flow from the sensors to the motors exhibiting the optimal situation when the body dynamics drive the controllers (mutual entrainment). Based on our results, we discuss the relevance of our findings for modeling the modular control of distributed pattern generators exhibited in the spinal cord, and for exploring the motor synergies in robots. PMID:20011216
Generalized Kraus operators and generators of quantum dynamical semigroups
NASA Astrophysics Data System (ADS)
Alazzawi, Sabina; Baumgartner, Bernhard
2015-09-01
Quantum dynamical semigroups play an important role in the description of physical processes such as diffusion, radiative decay or other non-equilibrium events. Taking strongly continuous and trace preserving semigroups into consideration, we show that, under a special criterion, the generator of such a group admits a certain generalized standard form, thereby shedding new light on known approaches in this direction. Furthermore, we illustrate our analysis in concrete examples.
Role of Many-Electron Dynamics in High Harmonic Generation
Gordon, Ariel; Kaertner, Franz X.; Rohringer, Nina; Santra, Robin
2006-06-09
High harmonic generation (HHG) in many-electron atoms is studied theoretically. The breakdown of the frozen-core single active electron approximation is demonstrated, as it predicts roughly the same radiation amplitude in all noble gases. This is in contradiction with experiments, where heavier noble gases are known to emit much stronger HHG radiation than lighter ones. This experimental behavior of the noble gases can be qualitatively reproduced when many-electron dynamics, within a simple approximation, is taken into account.
Numerical study of dynamical mass generation in QED3
NASA Astrophysics Data System (ADS)
Bashir, A.; Huet, A.; Raya, A.
2006-05-01
We carry out a numerical study of dynamical generation of fermion masses by solving the Schwinger-Dyson equation for the fermion propagator in three-dimensional quenched Quantum Electrodynamics (QED3) in various gauges. We employ an ansatz for the three-point vertex which satisfies the Ward-Green-Takahashi identity, namely, the Ball-Chiu Vertex. We discuss the advantages of our numerical method over some earlier ones.
Dynamical generation of the weak and dark matter scale
NASA Astrophysics Data System (ADS)
Hambye, Thomas; Strumia, Alessandro
2013-09-01
Assuming that naturalness should be modified by ignoring quadratic divergences, we propose a simple extension of the standard model where the weak scale is dynamically generated together with an automatically stable vector. Identifying it as thermal dark matter, the model has one free parameter. It predicts one extra scalar, detectable at colliders, which triggers a first-order dark/electroweak cosmological phase transition with production of gravitational waves. Vacuum stability holds up to the Planck scale.
Modeling Airborne Beryllium Concentrations From Open Air Dynamic Testing
NASA Astrophysics Data System (ADS)
Becker, N. M.
2003-12-01
A heightened awareness of airborne beryllium contamination from industrial activities was reestablished during the late 1980's and early 1990's when it became recognized that Chronic Beryllium Disease (CBD) had not been eradicated, and that the Occupational Health and Safety Administration standards for occupational air exposure to beryllium may not be sufficiently protective. This was in response to the observed CBD increase in multiple industrial settings where beryllium was manufactured and/or machined, thus producing beryllium particulates which are then available for redistribution by airborne transport. Sampling and modeling design activities were expanded at Los Alamos National Laboratory in New Mexico to evaluate potential airborne beryllium exposure to workers who might be exposed during dynamic testing activities associated with nuclear weapons Stockpile Stewardship. Herein is presented the results of multiple types of collected air measurements that were designed to characterize the production and dispersion of beryllium used in components whose performance is evaluated during high explosive detonation at open air firing sites. Data from fallout, high volume air, medium volume air, adhesive film, particle size impactor, and fine-particulate counting techniques will be presented, integrated, and applied in dispersion modeling to assess potential onsite and offsite personal exposures resulting from dynamic testing activities involving beryllium.
Generational Spreading Speed and the Dynamics of Population Range Expansion.
Bateman, Andrew W; Neubert, Michael G; Krkošek, Martin; Lewis, Mark A
2015-09-01
Some of the most fundamental quantities in population ecology describe the growth and spread of populations. Population dynamics are often characterized by the annual rate of increase, λ, or the generational rate of increase, R0. Analyses involving R0 have deepened our understanding of disease dynamics and life-history complexities beyond that afforded by analysis of annual growth alone. While range expansion is quantified by the annual spreading speed, a spatial analog of λ, an R0-like expression for the rate of spread is missing. Using integrodifference models, we derive the appropriate generational spreading speed for populations with complex (stage-structured) life histories. The resulting measure, relevant to locations near the expanding edge of a (re)colonizing population, incorporates both local population growth and explicit spatial dispersal rather than solely growth across a population, as is the case for R0. The calculations for generational spreading speed are often simpler than those for annual spreading speed, and analytic or partial analytic solutions can yield insight into the processes that facilitate or slow a population's spatial spread. We analyze the spatial dynamics of green crabs, sea otters, and teasel as examples to demonstrate the flexibility of our methods and the intuitive insights that they afford. PMID:26655354
PREVENTION OF ACID MINE DRAINAGE GENERATION FROM OPEN-PIT MINE HIGHWALLS
Exposed, open pit mine highwalls contribute significantly to the production of acid mine
drainage (AMD) thus causing environmental concerns upon closure of an operating mine. Available information on the generation of AMD from open-pit mine highwalls is very limit...
Dynamic test input generation for multiple-fault isolation
NASA Technical Reports Server (NTRS)
Schaefer, Phil
1990-01-01
Recent work is Causal Reasoning has provided practical techniques for multiple fault diagnosis. These techniques provide a hypothesis/measurement diagnosis cycle. Using probabilistic methods, they choose the best measurements to make, then update fault hypotheses in response. For many applications such as computers and spacecraft, few measurement points may be accessible, or values may change quickly as the system under diagnosis operates. In these cases, a hypothesis/measurement cycle is insufficient. A technique is presented for a hypothesis/test-input/measurement diagnosis cycle. In contrast to generating tests a priori for determining device functionality, it dynamically generates tests in response to current knowledge about fault probabilities. It is shown how the mathematics previously used for measurement specification can be applied to the test input generation process. An example from an efficient implementation called Multi-Purpose Causal (MPC) is presented.
Integration of an open interface PC scene generator using COTS DVI converter hardware
NASA Astrophysics Data System (ADS)
Nordland, Todd; Lyles, Patrick; Schultz, Bret
2006-05-01
Commercial-Off-The-Shelf (COTS) personal computer (PC) hardware is increasingly capable of computing high dynamic range (HDR) scenes for military sensor testing at high frame rates. New electro-optical and infrared (EO/IR) scene projectors feature electrical interfaces that can accept the DVI output of these PC systems. However, military Hardware-in-the-loop (HWIL) facilities such as those at the US Army Aviation and Missile Research Development and Engineering Center (AMRDEC) utilize a sizeable inventory of existing projection systems that were designed to use the Silicon Graphics Incorporated (SGI) digital video port (DVP, also known as DVP2 or DD02) interface. To mate the new DVI-based scene generation systems to these legacy projection systems, CG2 Inc., a Quantum3D Company (CG2), has developed a DVI-to-DVP converter called Delta DVP. This device takes progressive scan DVI input, converts it to digital parallel data, and combines and routes color components to derive a 16-bit wide luminance channel replicated on a DVP output interface. The HWIL Functional Area of AMRDEC has developed a suite of modular software to perform deterministic real-time, wave band-specific rendering of sensor scenes, leveraging the features of commodity graphics hardware and open source software. Together, these technologies enable sensor simulation and test facilities to integrate scene generation and projection components with diverse pedigrees.
Upon Generating (2+1)-dimensional Dynamical Systems
NASA Astrophysics Data System (ADS)
Zhang, Yufeng; Bai, Yang; Wu, Lixin
2016-06-01
Under the framework of the Adler-Gel'fand-Dikii(AGD) scheme, we first propose two Hamiltonian operator pairs over a noncommutative ring so that we construct a new dynamical system in 2+1 dimensions, then we get a generalized special Novikov-Veselov (NV) equation via the Manakov triple. Then with the aid of a special symmetric Lie algebra of a reductive homogeneous group G, we adopt the Tu-Andrushkiw-Huang (TAH) scheme to generate a new integrable (2+1)-dimensional dynamical system and its Hamiltonian structure, which can reduce to the well-known (2+1)-dimensional Davey-Stewartson (DS) hierarchy. Finally, we extend the binormial residue representation (briefly BRR) scheme to the super higher dimensional integrable hierarchies with the help of a super subalgebra of the super Lie algebra sl(2/1), which is also a kind of symmetric Lie algebra of the reductive homogeneous group G. As applications, we obtain a super 2+1 dimensional MKdV hierarchy which can be reduced to a super 2+1 dimensional generalized AKNS equation. Finally, we compare the advantages and the shortcomings for the three schemes to generate integrable dynamical systems.
The Dynamical Generation of Current Sheets in Astrophysical Plasma Turbulence
NASA Astrophysics Data System (ADS)
Howes, Gregory G.
2016-08-01
Turbulence profoundly affects particle transport and plasma heating in many astrophysical plasma environments, from galaxy clusters to the solar corona and solar wind to Earth's magnetosphere. Both fluid and kinetic simulations of plasma turbulence ubiquitously generate coherent structures, in the form of current sheets, at small scales, and the locations of these current sheets appear to be associated with enhanced rates of dissipation of the turbulent energy. Therefore, illuminating the origin and nature of these current sheets is critical to identifying the dominant physical mechanisms of dissipation, a primary aim at the forefront of plasma turbulence research. Here, we present evidence from nonlinear gyrokinetic simulations that strong nonlinear interactions between counterpropagating Alfvén waves, or strong Alfvén wave collisions, are a natural mechanism for the generation of current sheets in plasma turbulence. Furthermore, we conceptually explain this current sheet development in terms of the nonlinear dynamics of Alfvén wave collisions, showing that these current sheets arise through constructive interference among the initial Alfvén waves and nonlinearly generated modes. The properties of current sheets generated by strong Alfvén wave collisions are compared to published observations of current sheets in the Earth's magnetosheath and the solar wind, and the nature of these current sheets leads to the expectation that Landau damping of the constituent Alfvén waves plays a dominant role in the damping of turbulently generated current sheets.
Dynamics of the coronas of open star clusters
NASA Astrophysics Data System (ADS)
Danilov, V. M.; Putkov, S. I.; Seleznev, A. F.
2014-12-01
A method for distinguishing coronas in models of open star clusters is proposed. The method uses trajectories of stars that do not leave the coronas over time intervals t comparable to the mean lifetime τ of the clusters. Corona models are constructed for six numerical cluster models, and the direction and character of the dynamical evolution of the coronas are determined. Retrograde stellar motions are dominant in the coronas. In spite of some signs of dynamical instability of the coronas (small densities compared to the critical density and accelerated expansion of the coronas), the formation of close-toequilibrium density and phase-density distributions at distances from one to three cluster tidal radii from the cluster center can be seen. Approximations are constructed for the corona and cluster phase density using distributions that depend on three parameters (the parameters of the stellar motion in the Lindblad rotating coordinate system). This temporary equilibrium of the corona is due to balance in the number of starsmoving from the central areas of the cluster to the corona, and from the corona to the corona periphery or beyond. Evidence that corona stars can be gravitationally bound at distances out to four tidal radii from the cluster center is found: the presence of nearly periodic retrograde mean motions of a large number of corona stars in the Galactic plane; 91-99% of corona stars satisfy the gravitational binding criterion of Ross, Mennim and Heggie over time intervals that are close to the mean cluster lifetime. The escape rate from the corona is estimated for t ≥ τ, and found to be from 0.03 to 0.23 of the number of corona stars per violent relaxation time.
Improving Dynamic Load and Generator Response PerformanceTools
Lesieutre, Bernard C.
2005-11-01
This report is a scoping study to examine research opportunities to improve the accuracy of the system dynamic load and generator models, data and performance assessment tools used by CAISO operations engineers and planning engineers, as well as those used by their counterparts at the California utilities, to establish safe operating margins. Model-based simulations are commonly used to assess the impact of credible contingencies in order to determine system operating limits (path ratings, etc.) to ensure compliance with NERC and WECC reliability requirements. Improved models and a better understanding of the impact of uncertainties in these models will increase the reliability of grid operations by allowing operators to more accurately study system voltage problems and the dynamic stability response of the system to disturbances.
NASA Astrophysics Data System (ADS)
Redeckas, Kipras; Toliautas, Stepas; Steponavičiūtė, Rasa; Šačkus, Algirdas; Sulskus, Juozas; Vengris, Mikas
2016-06-01
Steady-state and time-resolved femtosecond stimulated Raman scattering spectroscopic methods were applied to elucidate the photodynamics and the oxazine ring opening contingency in phenyl-substituted indolobenzoxazine systems. Using wavelength- and pulse duration-tunable multi-pulse techniques, we have measured the (static) stimulated Raman spectra of the chemically ring-opened indolobenzoxazines, and the (dynamic) femto-to-nanosecond time- and wavenumber-resolved spectra of their photo-generated species. The two experimental realizations show a notable vibronic disparity, thereby indicating the structural difference between the chemically bond-cleaved and the UV excitation produced species.
Ferré, A.; Boguslavskiy, A. E.; Dagan, M.; Blanchet, V.; Bruner, B. D.; Burgy, F.; Camper, A.; Descamps, D.; Fabre, B.; Fedorov, N.; Gaudin, J.; Geoffroy, G.; Mikosch, J.; Patchkovskii, S.; Petit, S.; Ruchon, T.; Soifer, H.; Staedter, D.; Wilkinson, I.; Stolow, A.; Dudovich, N.; Mairesse, Y.
2015-01-01
High-order harmonic generation in polyatomic molecules generally involves multiple channels of ionization. Their relative contribution can be strongly influenced by the presence of resonances, whose assignment remains a major challenge for high-harmonic spectroscopy. Here we present a multi-modal approach for the investigation of unaligned polyatomic molecules, using SF6 as an example. We combine methods from extreme-ultraviolet spectroscopy, above-threshold ionization and attosecond metrology. Fragment-resolved above-threshold ionization measurements reveal that strong-field ionization opens at least three channels. A shape resonance in one of them is found to dominate the signal in the 20–26 eV range. This resonance induces a phase jump in the harmonic emission, a switch in the polarization state and different dynamical responses to molecular vibrations. This study demonstrates a method for extending high-harmonic spectroscopy to polyatomic molecules, where complex attosecond dynamics are expected. PMID:25608712
Ferré, A; Boguslavskiy, A E; Dagan, M; Blanchet, V; Bruner, B D; Burgy, F; Camper, A; Descamps, D; Fabre, B; Fedorov, N; Gaudin, J; Geoffroy, G; Mikosch, J; Patchkovskii, S; Petit, S; Ruchon, T; Soifer, H; Staedter, D; Wilkinson, I; Stolow, A; Dudovich, N; Mairesse, Y
2015-01-01
High-order harmonic generation in polyatomic molecules generally involves multiple channels of ionization. Their relative contribution can be strongly influenced by the presence of resonances, whose assignment remains a major challenge for high-harmonic spectroscopy. Here we present a multi-modal approach for the investigation of unaligned polyatomic molecules, using SF6 as an example. We combine methods from extreme-ultraviolet spectroscopy, above-threshold ionization and attosecond metrology. Fragment-resolved above-threshold ionization measurements reveal that strong-field ionization opens at least three channels. A shape resonance in one of them is found to dominate the signal in the 20-26 eV range. This resonance induces a phase jump in the harmonic emission, a switch in the polarization state and different dynamical responses to molecular vibrations. This study demonstrates a method for extending high-harmonic spectroscopy to polyatomic molecules, where complex attosecond dynamics are expected. PMID:25608712
Bright bichromatic entanglement and quantum dynamics of sum frequency generation
Olsen, M. K.; Bradley, A. S.
2008-02-15
We investigate the quantum properties of the well-known process of sum frequency generation, showing that it is potentially a very useful source of nonclassical states of the electromagnetic field, some of which are not possible with the more common techniques. We show that it can produce quadrature squeezed light, bright bichromatic entangled states, and symmetric and asymmetric demonstrations of the Einstein-Podolsky-Rosen paradox. We also show that the semiclassical equations totally fail to describe the mean-field dynamics when the cavity is strongly pumped.
Dynamic stability experiments in sodium-heated steam generators. [LMFBR
France, D.M.; Roy, R.; Carlson, R.D.; Chiang, T.
1984-01-01
Seventy-two dynamic stability tests were performed in the sodium-heated boiling-water test facility at Argonne National Laboratory. A full-scale LMFBR steam generator tube was employed as the test section operating over the water parameter ranges of 6.9 to 15.9 MPa pressure and 170 to 800 kg/m/sup 2/.s mass flux. The stability thresholds from the test compared well to the predictions of a modified version of a correlation equation recently published by other investigators. Typical experimental data and the modified correlation equation are presented.
Nonlinear dynamic model of a solar stream generator
NASA Astrophysics Data System (ADS)
Ray, A.
1981-01-01
A thermal-hydraulic model of a once-through subcritical steam generator has been developed for predicting dynamic characteristics of solar thermal power plants as well as for control system design. The purpose of the model is to evaluate the overall system performance and component interaction with sufficient accuracy for controller design, rather than to describe the microscopic details occurring within the steam generator. The three-section (compressed water, two-phase mixture, and superheated steam) model with time-varying phase boundaries is described by a set of nonlinear differential equations derived from conservation of mass, momentum and energy. Local stability of the model has been examined at different levels of insolation. Transient response of six plant variables due to independent step disturbances in three input variables are presented as typical results.
Openness, Dynamic Specialization, and the Disaggregated Future of Higher Education
ERIC Educational Resources Information Center
Wiley, David; Hilton, John, III
2009-01-01
Openness is a fundamental value underlying significant changes in society and is a prerequisite to changes institutions of higher education need to make in order to remain relevant to the society in which they exist. There are a number of ways institutions can be more open, including programs of open sharing of educational materials. Individual…
Dynamics of microresonator frequency comb generation: models and stability
NASA Astrophysics Data System (ADS)
Hansson, Tobias; Wabnitz, Stefan
2016-06-01
Microresonator frequency combs hold promise for enabling a new class of light sources that are simultaneously both broadband and coherent, and that could allow for a profusion of potential applications. In this article, we review various theoretical models for describing the temporal dynamics and formation of optical frequency combs. These models form the basis for performing numerical simulations that can be used in order to better understand the comb generation process, for example helping to identify the universal combcharacteristics and their different associated physical phenomena. Moreover, models allow for the study, design and optimization of comb properties prior to the fabrication of actual devices. We consider and derive theoretical formalisms based on the Ikeda map, the modal expansion approach, and the Lugiato-Lefever equation. We further discuss the generation of frequency combs in silicon resonators featuring multiphoton absorption and free-carrier effects. Additionally, we review comb stability properties and consider the role of modulational instability as well as of parametric instabilities due to the boundary conditions of the cavity. These instability mechanisms are the basis for comprehending the process of frequency comb formation, for identifying the different dynamical regimes and the associated dependence on the comb parameters. Finally, we also discuss the phenomena of continuous wave bi- and multistability and its relation to the observation of mode-locked cavity solitons.
IllinoisGRMHD: an open-source, user-friendly GRMHD code for dynamical spacetimes
NASA Astrophysics Data System (ADS)
Etienne, Zachariah B.; Paschalidis, Vasileios; Haas, Roland; Mösta, Philipp; Shapiro, Stuart L.
2015-09-01
In the extreme violence of merger and mass accretion, compact objects like black holes and neutron stars are thought to launch some of the most luminous outbursts of electromagnetic and gravitational wave energy in the Universe. Modeling these systems realistically is a central problem in theoretical astrophysics, but has proven extremely challenging, requiring the development of numerical relativity codes that solve Einstein's equations for the spacetime, coupled to the equations of general relativistic (ideal) magnetohydrodynamics (GRMHD) for the magnetized fluids. Over the past decade, the Illinois numerical relativity (ILNR) group's dynamical spacetime GRMHD code has proven itself as a robust and reliable tool for theoretical modeling of such GRMHD phenomena. However, the code was written ‘by experts and for experts’ of the code, with a steep learning curve that would severely hinder community adoption if it were open-sourced. Here we present IllinoisGRMHD, which is an open-source, highly extensible rewrite of the original closed-source GRMHD code of the ILNR group. Reducing the learning curve was the primary focus of this rewrite, with the goal of facilitating community involvement in the code's use and development, as well as the minimization of human effort in generating new science. IllinoisGRMHD also saves computer time, generating roundoff-precision identical output to the original code on adaptive-mesh grids, but nearly twice as fast at scales of hundreds to thousands of cores.
How memory generates heterogeneous dynamics in temporal networks.
Vestergaard, Christian L; Génois, Mathieu; Barrat, Alain
2014-10-01
Empirical temporal networks display strong heterogeneities in their dynamics, which profoundly affect processes taking place on these networks, such as rumor and epidemic spreading. Despite the recent wealth of data on temporal networks, little work has been devoted to the understanding of how such heterogeneities can emerge from microscopic mechanisms at the level of nodes and links. Here we show that long-term memory effects are present in the creation and disappearance of links in empirical networks. We thus consider a simple generative modeling framework for temporal networks able to incorporate these memory mechanisms. This allows us to study separately the role of each of these mechanisms in the emergence of heterogeneous network dynamics. In particular, we show analytically and numerically how heterogeneous distributions of contact durations, of intercontact durations, and of numbers of contacts per link emerge. We also study the individual effect of heterogeneities on dynamical processes, such as the paradigmatic susceptible-infected epidemic spreading model. Our results confirm in particular the crucial role of the distributions of intercontact durations and of the numbers of contacts per link. PMID:25375547
Shadow correction in high dynamic range images for generating orthophotos
NASA Astrophysics Data System (ADS)
Suzuki, Hideo; Chikatsu, Hirofumi
2011-07-01
High dynamic range imagery is widely used in remote sensing. With the widespread use of aerial digital cameras such as the DMC, ADS40, RMK-D, and UltraCamD, high dynamic range imaging is generally expected for generating minuteness orthophotos in digital aerial photogrammetry. However, high dynamic range images (12-bit, 4,096 gray levels) are generally compressed into an 8-bit depth digital image (256 gray levels) owing to huge amount of data and interface with peripherals such as monitors and printers. This means that a great deal of image data is eliminated from the original image, and this introduces a new shadow problem. In particular, the influence of shadows in urban areas causes serious problems when generating minuteness orthophotos and performing house detection. Therefore, shadow problems can be solved by addressing the image compression problems. There is a large body of literature on image compression techniques such as logarithmic compression and tone mapping algorithms. However, logarithmic compression tends to cause loss of details in dark and/or light areas. Furthermore, the logarithmic method intends to operate on the full scene. This means that high-resolution luminance information can not be obtained. Even though tone mapping algorithms have the ability to operate over both full scene and local scene, background knowledge is required. To resolve the shadow problem in digital aerial photogrammetry, shadow areas should be recognized and corrected automatically without the loss of luminance information. To this end, a practical shadow correction method using 12-bit real data acquired by DMC is investigated in this paper.
Stochastic-Dynamic Earthquake Models and Tsunami Generation
NASA Astrophysics Data System (ADS)
Oglesby, D. D.; Geist, E. L.
2013-12-01
Dynamic models are now understood to provide physically plausible faulting scenarios for ground motion prediction, but their use in tsunami hazard analysis is in its infancy. Typical tsunami model generation methods rely on kinematic or dislocation models of the earthquake source, in which the seismic moment, rupture path, and slip distribution are assumed a priori, typically based on models of prior earthquakes, aftershock distributions, and/or some sort of stochastic slip model. However, such models are not guaranteed to be consistent with any physically plausible faulting scenario and may span a range of parameter space far outside of what is physically realistic. In contrast, in dynamic models the earthquake rupture and slip process (including the final size of the earthquake, the spatiotemporal evolution of slip, and the rupture path on complex fault geometry) are calculated results of the models. Utilizing the finite element method, a self-affine stochastic stress field, and a shallow-water hydrodynamic code, we calculate a suite of dynamic slip models and near-source tsunamis from a megathrust/splay fault system motivated by the geometry in the Nankai region of Japan. Different stress realizations produce different spatial patterns of slip, including different partitioning between the megathrust and splay segments. Because the final moment from different stress realizations can differ, and because partitioning of slip between fault segments has a first-order effect on the surface deformation and tsunami generation, the modeled near-source tsunamis are also highly variable. Models whose stress amplitudes have been scaled to produce equivalent seismic moments (but with the same spatial variability and relative fault strength as the previous unscaled models) have less variability in tsunami amplitude in regions far from the fault, but greater variability in amplitude in the near-fault region.
Dynamics of the Open Closed Field Line Boundary
NASA Astrophysics Data System (ADS)
Spanswick, E.; Roy, E.; Nishimura, T.; Unick, C.; Jackel, B. J.; Donovan, E.
2015-12-01
In most cases, large-scale features of the auroral distribution are the projection, along magnetic field lines, of corresponding magnetospheric features. The poleward boundary of the oval is a key example of such a feature. At almost all local times, this is most often interpreted as the ionospheric marker of the latitudinal transition between open lobe and closed central plasma sheet field lines. Earlier work by Blanchard et al. [J. Geophys. Res., 1995 & 1997] used ground-based photometric observations of 630 nm "redline" aurora and in situ particle observations from simultaneous DMSP overflights to demonstrate that the poleward boundary of the redline aurora is a particularly robust signature of the poleward boundary of the plasma sheet. Owing to the orbits of the DMSP spacecraft and the relative newness of the photometer program (CANOPUS) that provided the optical observations, the Blanchard results represent a limited sampling of magnetic local time and a limited number of events. In this paper we revisit the Blanchard et al study, using particle data from the NASA FAST satellite and the DMSP program, together with redline observations obtained by ground-based All-Sky Imagers. Our results indicate that the Blanchard technique for identifying the polar cap boundary holds true for essentially all magnetic local times on the night side, but that the picture is more nuanced than previously appreciated. Here we present these results, and discuss specific examples where the technique does not work (and explore why). Furthermore, this work is motivated by a new extensive network of highly sensitive redline imagers that has been deployed across northern and central Canada which provides high time resolution large-scale snapshots of the instantaneous polar cap boundary. This in turn enables us to explore magnetospheric dynamics at the interface between the lobe and central plasma sheet in fundamentally new and exciting ways.
Excitation and dynamics of liquid tin micrometer droplet generation
NASA Astrophysics Data System (ADS)
Rollinger, B.; Abhari, R. S.
2016-07-01
The dynamics of capillary breakup-based droplet generation are studied for an excitation system based on a tunable piezoelectrically actuated oscillating piston, which generates acoustic pressure waves at the dispenser nozzle. First, the non-ideal pressure boundary conditions of droplet breakup are measured using a fast response pressure probe. A structural analysis shows that the axial modes of the excitation system are the main reasons for the resonance peaks in the pressure response. Second, a correlation between the nozzle inlet pressure and the droplet timing jitter is established with the help of experiments and a droplet formation model. With decreasing wave number, the growth rate of the main excitation decreases, while noise contributions with wave numbers with higher growth rates lead to a non-deterministic structure of the droplet train. A highly coherent and monodisperse droplet stream is obtained when the excitation system is tuned to generate high acoustic pressures at the desired operation frequency and when the noise level on the jet is limited. The jet velocity, hence droplet spacing for a set frequency is then adjusted by varying the reservoir pressure, according to the trade-off between lowest wave number and acceptable timing jitter.
OPEN PROBLEM: Orbits' statistics in chaotic dynamical systems
NASA Astrophysics Data System (ADS)
Arnold, V.
2008-07-01
This paper shows how the measurement of the stochasticity degree of a finite sequence of real numbers, published by Kolmogorov in Italian in a journal of insurances' statistics, can be usefully applied to measure the objective stochasticity degree of sequences, originating from dynamical systems theory and from number theory. Namely, whenever the value of Kolmogorov's stochasticity parameter of a given sequence of numbers is too small (or too big), one may conclude that the conjecture describing this sequence as a sample of independent values of a random variables is highly improbable. Kolmogorov used this strategy fighting (in a paper in 'Doklady', 1940) against Lysenko, who had tried to disprove the classical genetics' law of Mendel experimentally. Calculating his stochasticity parameter value for the numbers from Lysenko's experiment reports, Kolmogorov deduced, that, while these numbers were different from the exact fulfilment of Mendel's 3 : 1 law, any smaller deviation would be a manifestation of the report's number falsification. The calculation of the values of the stochasticity parameter would be useful for many other generators of pseudorandom numbers and for many other chaotically looking statistics, including even the prime numbers distribution (discussed in this paper as an example).
Coordinating the Commons: Diversity & Dynamics in Open Collaborations
ERIC Educational Resources Information Center
Morgan, Jonathan T.
2013-01-01
The success of Wikipedia demonstrates that open collaboration can be an effective model for organizing geographically-distributed volunteers to perform complex, sustained work at a massive scale. However, Wikipedia's history also demonstrates some of the challenges that large, long-term open collaborations face: the core community of Wikipedia…
Knowledge-based zonal grid generation for computational fluid dynamics
NASA Technical Reports Server (NTRS)
Andrews, Alison E.
1988-01-01
Automation of flow field zoning in two dimensions is an important step towards reducing the difficulty of three-dimensional grid generation in computational fluid dynamics. Using a knowledge-based approach makes sense, but problems arise which are caused by aspects of zoning involving perception, lack of expert consensus, and design processes. These obstacles are overcome by means of a simple shape and configuration language, a tunable zoning archetype, and a method of assembling plans from selected, predefined subplans. A demonstration system for knowledge-based two-dimensional flow field zoning has been successfully implemented and tested on representative aerodynamic configurations. The results show that this approach can produce flow field zonings that are acceptable to experts with differing evaluation criteria.
Weak decays of heavy hadrons into dynamically generated resonances
Oset, Eulogio; Liang, Wei -Hong; Bayar, Melahat; Xie, Ju -Jun; Dai, Lian Rong; Albaladejo, Miguel; Nielsen, Marina; Sekihara, Takayasu; Navarra, Fernando; Roca, Luis; et al
2016-01-28
In this study, we present a review of recent works on weak decay of heavy mesons and baryons with two mesons, or a meson and a baryon, interacting strongly in the final state. The aim is to learn about the interaction of hadrons and how some particular resonances are produced in the reactions. It is shown that these reactions have peculiar features and act as filters for some quantum numbers which allow to identify easily some resonances and learn about their nature. The combination of basic elements of the weak interaction with the framework of the chiral unitary approach allowmore » for an interpretation of results of many reactions and add a novel information to different aspects of the hadron interaction and the properties of dynamically generated resonances.« less
Force Generation, Polymerization Dynamics and Nucleation of Actin Filaments
NASA Astrophysics Data System (ADS)
Wang, Ruizhe
We study force generation and actin filament dynamics using stochastic and deterministic methods. First, we treat force generation of bundled actin filaments by polymerization via molecular-level stochastic simulations. In the widely-used Brownian Ratchet model, actin filaments grow freely whenever the tip-obstacle gap created by thermal fluctuation exceeds the monomer size. We name this model the Perfect Brownian Ratchet (PBR) model. In the PBR model, actin monomer diffusion is treated implicitly. We perform a series of simulations based on the PBR, in which obstacle motion is treated explicitly; in most previous studies, obstacle motion has been treated implicitly. We find that the cooperativity of filaments is generally weak in the PBR model, meaning that more filaments would grow more slowly given the same force per filament. Closed-form formulas are also developed, which match the simulation results. These portable and accurate formulas provide guidance for experiments and upper and lower bounds for theoretical analyses. We also studied a variation of the PBR, called the Diffusing Brownian Ratchet (DBR) model, in which both actin monomer and obstacle diffusion are treated explicitly. We find that the growth rate of multiple filaments is even lower, compared with that in PBR. This finding challenges the widely-accepted PBR assumption and suggests that pushing the study of actin dynamics down to the sub-nanometer level yields new insights. We subsequently used a rate equation approach to model the effect of local depletion of actin monomers on the nucleation of actin filaments on biomimetic beads, and how the effect is regulated by capping protein (CP). We find that near the bead surface, a higher CP concentration increases local actin concentration, which leads to an enhanced activities of actin filaments' nucleation. Our model analysis matches the experimental results and lends support to an important but undervalued hypothesis proposed by Carlier and
Coupled ice-ocean dynamics in the marginal ice zones Upwelling/downwelling and eddy generation
NASA Technical Reports Server (NTRS)
Hakkinen, S.
1986-01-01
This study is aimed at modeling mesoscale processes such as upwelling/downwelling and ice edge eddies in the marginal ice zones. A two-dimensional coupled ice-ocean model is used for the study. The ice model is coupled to the reduced gravity ocean model through interfacial stresses. The parameters of the ocean model were chosen so that the dynamics would be nonlinear. The model was tested by studying the dynamics of upwelling. Wings parallel to the ice edge with the ice on the right produce upwelling because the air-ice momentum flux is much greater than air-ocean momentum flux; thus the Ekman transport is greater than the ice than in the open water. The stability of the upwelling and downwelling jets is discussed. The downwelling jet is found to be far more unstable than the upwelling jet because the upwelling jet is stabilized by the divergence. The constant wind field exerted on a varying ice cover will generate vorticity leading to enhanced upwelling/downwelling regions, i.e., wind-forced vortices. Steepening and strengthening of vortices are provided by the nonlinear terms. When forcing is time-varying, the advection terms will also redistribute the vorticity. The wind reversals will separate the vortices from the ice edge, so that the upwelling enhancements are pushed to the open ocean and the downwelling enhancements are pushed underneath the ice.
Free viewpoint image generation using multi-pass dynamic programming
NASA Astrophysics Data System (ADS)
Fukushima, Norishige; Yendo, Tomohiro; Fujii, Toshiaki; Tanimoto, Masayuki
2007-02-01
Ray-Space is categorized by Image-Based Rendering (IBR), thus generated views have photo-realistic quality. While this method has the performance of high quality imaging, this needs a lot of images or cameras. The reason why that is Ray-Space requires various direction's and position's views instead of 3D depth information. In this paper, we reduce that flood of information using view-centered ray interpolation. View-centered interpolation means estimating view dependent depth value (or disparity map) at generating view-point and interpolating that of pixel values using multi-view images and depth information. The combination of depth estimation and interpolation realizes the rendering photo-realistic images effectively. Unfortunately, however, if depth estimation is week or mistake, a lot of artifacts appear in creating images. Thus powerful depth estimation method is required. When we render the free viewpoint images video, we perform the depth estimation at every frame. Thus we want to keep a lid on computing cost. Our depth estimation method is based on dynamic programming (DP). This method optimizes and solves depth images at the weak matching area with high-speed performance. But scan-line noises become appeared because of the limit of DP. So, we perform the DP multi-direction pass and sum-up the result of multi-passed DPs. Our method fulfills the low computation cost and high depth estimation performance.
Teachers' Performances during a Practical Dynamic Open Inquiry Process
ERIC Educational Resources Information Center
Zion, Michal; Schanin, Ilana; Shmueli, Ester Rimerman
2013-01-01
The research goal of this study was to determine whether teachers who participated in an inquiry-based course were able to internalize a dynamic open inquiry process. This study focused on 25 science teachers who participated in an annual inquiry-based academic course. Several teaching tools helped teachers employ an open inquiry process. We…
MINE WASTE TECHNOLOGY PROGRAM PREVENTION OF ACID MINE DRAINAGE GENERATION FROM OPEN-PIT HIGHWALLS
This document summarizes the results of Mine Waste Technology Program Activity III, Project 26, Prevention of Acid Mine Drainage Generation from Open-Pit Highwalls. The intent of this project was to obtain performance data on the ability of four technologies to prevent the gener...
The Evolution of Open Magnetic Flux Driven by Photospheric Dynamics
NASA Technical Reports Server (NTRS)
Linker, Jon A.; Lionello, Roberto; Mikic, Zoran; Titov, Viacheslav S.; Antiochos, Spiro K.
2010-01-01
The coronal magnetic field is of paramount importance in solar and heliospheric physics. Two profoundly different views of the coronal magnetic field have emerged. In quasi-steady models, the predominant source of open magnetic field is in coronal holes. In contrast, in the interchange model, the open magnetic flux is conserved, and the coronal magnetic field can only respond to the photospheric evolution via interchange reconnection. In this view the open magnetic flux diffuses through the closed, streamer belt fields, and substantial open flux is present in the streamer belt during solar minimum. However, Antiochos and co-workers, in the form of a conjecture, argued that truly isolated open flux cannot exist in a configuration with one heliospheric current sheet (HCS) - it will connect via narrow corridors to the polar coronal hole of the same polarity. This contradicts the requirements of the interchange model. We have performed an MHD simulation of the solar corona up to 20R solar to test both the interchange model and the Antiochos conjecture. We use a synoptic map for Carrington Rotation 1913 as the boundary condition for the model, with two small bipoles introduced into the region where a positive polarity extended coronal hole forms. We introduce flows at the photospheric boundary surface to see if open flux associated with the bipoles can be moved into the closed-field region. Interchange reconnection does occur in response to these motions. However, we find that the open magnetic flux cannot be simply injected into closed-field regions - the flux eventually closes down and disconnected flux is created. Flux either opens or closes, as required, to maintain topologically distinct open and closed field regions, with no indiscriminate mixing of the two. The early evolution conforms to the Antiochos conjecture in that a narrow corridor of open flux connects the portion of the coronal hole that is nearly detached by one of the bipoles. In the later evolution, a
NASA Astrophysics Data System (ADS)
Harada, Ryuhei; Kitao, Akio
2013-07-01
Parallel Cascade Selection Molecular Dynamics (PaCS-MD) is proposed as a molecular simulation method to generate conformational transition pathway under the condition that a set of "reactant" and "product" structures is known a priori. In PaCS-MD, the cycle of short multiple independent molecular dynamics simulations and selection of the structures close to the product structure for the next cycle are repeated until the simulated structures move sufficiently close to the product. Folding of 10-residue mini-protein chignolin from the extended to native structures and open-close conformational transition of T4 lysozyme were investigated by PaCS-MD. In both cases, tens of cycles of 100-ps MD were sufficient to reach the product structures, indicating the efficient generation of conformational transition pathway in PaCS-MD with a series of conventional MD without additional external biases. Using the snapshots along the pathway as the initial coordinates, free energy landscapes were calculated by the combination with multiple independent umbrella samplings to statistically elucidate the conformational transition pathways.
NASA Astrophysics Data System (ADS)
Dahlem, Markus A.
2013-12-01
Migraine is a common disabling headache disorder characterized by recurrent episodes sometimes preceded or accompanied by focal neurological symptoms called aura. The relation between two subtypes, migraine without aura (MWoA) and migraine with aura (MWA), is explored with the aim to identify targets for neuromodulation techniques. To this end, a dynamically regulated control system is schematically reduced to a network of the trigeminal nerve, which innervates the cranial circulation, an associated descending modulatory network of brainstem nuclei, and parasympathetic vasomotor efferents. This extends the idea of a migraine generator region in the brainstem to a larger network and is still simple and explicit enough to open up possibilities for mathematical modeling in the future. In this study, it is suggested that the migraine generator network (MGN) is driven and may therefore respond differently to different spatio-temporal noxious input in the migraine subtypes MWA and MWoA. The noxious input is caused by a cortical perturbation of homeostasis, known as spreading depression (SD). The MGN might even trigger SD in the first place by a failure in vasomotor control. As a consequence, migraine is considered as an inherently dynamical disease to which a linear course from upstream to downstream events would not do justice. Minimally invasive and noninvasive neuromodulation techniques are briefly reviewed and their rational is discussed in the context of the proposed mechanism.
Open-Source Programming for Automated Generation of Graphene Raman Spectral Maps
NASA Astrophysics Data System (ADS)
Vendola, P.; Blades, M.; Pierre, W.; Jedlicka, S.; Rotkin, S. V.
Raman microscopy is a useful tool for studying the structural characteristics of graphene deposited onto substrates. However, extracting useful information from the Raman spectra requires data processing and 2D map generation. An existing home-built confocal Raman microscope was optimized for graphene samples and programmed to automatically generate Raman spectral maps across a specified area. In particular, an open source data collection scheme was generated to allow the efficient collection and analysis of the Raman spectral data for future use. NSF ECCS-1509786.
Dynamic headspace generation and quantitation of triacetone triperoxide vapor.
Giordano, Braden C; Lubrano, Adam L; Field, Christopher R; Collins, Greg E
2014-02-28
Two methods for quantitation of triacetone triperoxide (TATP) vapor using a programmable temperature vaporization (PTV) inlet coupled to a gas chromatography/mass spectrometer (GC/MS) have been demonstrated. The dynamic headspace of bulk TATP was mixed with clean humid air to produce a TATP vapor stream. Sampling via a heated transfer line to a PTV inlet with a Tenax-TA™ filled liner allowed for direct injection of the vapor stream to a GC/MS for vapor quantitation. TATP was extracted from the vapor stream and subsequently desorbed from the PTV liner for splitless injection on the GC column. Calibration curves were prepared using solution standards with a standard split/splitless GC inlet for quantitation of the TATP vapor. Alternatively, vapor was sampled onto a Tenax-TA™ sample tube and placed into a thermal desorption system. In this instance, vapor was desorbed from the tube and subsequently trapped on a liquid nitrogen cooled PTV inlet. Calibration curves for this method were prepared from direct liquid injection of standards onto samples tube with the caveat that a vacuum is applied to the tube during deposition to ensure that the volatile TATP penetrates into the tube. Vapor concentration measurements, as determined by either GC/MS analysis or mass gravimetry of the bulk TATP, were statistically indistinguishable. Different approaches to broaden the TATP vapor dynamic range, including diluent air flow, sample chamber temperature, sample vial orifice size, and sample size are discussed. Vapor concentrations between 50 and 5400ngL(-1) are reported, with stable vapor generation observed for as long as 60 consecutive hours. PMID:24508355
Open Automated Demand Response Technologies for Dynamic Pricing and Smart Grid
Ghatikar, Girish; Mathieu, Johanna L.; Piette, Mary Ann; Kiliccote, Sila
2010-06-02
We present an Open Automated Demand Response Communications Specifications (OpenADR) data model capable of communicating real-time prices to electricity customers. We also show how the same data model could be used to for other types of dynamic pricing tariffs (including peak pricing tariffs, which are common throughout the United States). Customers participating in automated demand response programs with building control systems can respond to dynamic prices by using the actual prices as inputs to their control systems. Alternatively, prices can be mapped into"building operation modes," which can act as inputs to control systems. We present several different strategies customers could use to map prices to operation modes. Our results show that OpenADR can be used to communicate dynamic pricing within the Smart Grid and that OpenADR allows for interoperability with existing and future systems, technologies, and electricity markets.
Nonequilibrium dynamics of laser-generated plasma channels
NASA Astrophysics Data System (ADS)
Petrova, Tz. B.; Ladouceur, H. D.; Baronavski, A. P.
2008-05-01
A time-dependent nonequilibrium kinetics model based upon the time-dependent electron Boltzmann equation coupled with an extensive air chemistry model accounting for gas heating and vibrational kinetics is developed. The model is applied to the temporal evolution of femtosecond laser-generated air plasma channels at atmospheric pressure in an external electric field. The plasma channel dynamics depend upon the initial free electron density, the initial electron energy of the plasma, and upon the externally applied electric field strength. The model predicts an electric breakdown field strength of 5-10kV/cm with a delay time of hundreds of nanoseconds when the electron density drops to the optimum value of ˜1012-1013cm-3. The experimentally observed breakdown field is ˜5.7kV/cm with a statistical breakdown delay time of ˜200ns. The reduction in the breakdown field strength in natural air from ˜30to5kV/cm is attributed to a combination of processes such as enhanced ionization due to relaxation of the initial electron energy distribution function toward a Maxwellian distribution, strong electron detachment, and gas heating. The calculated electron density decay of the laser-generated plasma channel in both pure nitrogen and dry air is in good agreement with the NRL experiments. The derived rate constant for recombination in dry air is bBair=3.9×10-8cm3s-1 and in pure nitrogen it is bBN2=4.4×10-8cm3s-1. The attachment rate coefficient in dry air is ηBair=7.5×106s-1.
Dynamic simulation and safety evaluation of high-speed trains meeting in open air
NASA Astrophysics Data System (ADS)
Li, Songyan; Zheng, Zhijun; Yu, Jilin; Qian, Chunqiang
2015-08-01
Dynamic responses of a carriage under excitation with the German high-speed low-interference track spectrum together with the air pressure pulse generated as high-speed trains passing each other are investigated with a multi-body dynamics method. The variations of degrees of freedom (DOFs: horizontal movement, roll angle, and yaw angle), the lateral wheel-rail force, the derailment coefficient, and the rate of wheel load reduction with time when two carriages meet in open air are obtained and compared with the results of a single train travelling at specified speeds. Results show that the rate of wheel load reduction increases with the increase of train speed and meets some safety standard at a certain speed, but exceeding the value of the rate of wheel load reduction does not necessarily mean derailment. The evaluation standard of the rate of wheel load reduction is somewhat conservative and may be loosened. The pressure pulse has significant effects on the train DOFs, and the evaluations of these safety indexes are strongly suggested in practice. The pressure pulse has a limited effect on the derailment coefficient and the lateral wheel-rail force, and, thus, their further evaluations may be not necessary.
Dynamic simulation and safety evaluation of high-speed trains meeting in open air
NASA Astrophysics Data System (ADS)
Li, Songyan; Zheng, Zhijun; Yu, Jilin; Qian, Chunqiang
2016-04-01
Dynamic responses of a carriage under excitation with the German high-speed low-interference track spectrum together with the air pressure pulse generated as high-speed trains passing each other are investigated with a multi-body dynamics method. The variations of degrees of freedom (DOFs: horizontal movement, roll angle, and yaw angle), the lateral wheel-rail force, the derailment coefficient, and the rate of wheel load reduction with time when two carriages meet in open air are obtained and compared with the results of a single train travelling at specified speeds. Results show that the rate of wheel load reduction increases with the increase of train speed and meets some safety standard at a certain speed, but exceeding the value of the rate of wheel load reduction does not necessarily mean derailment. The evaluation standard of the rate of wheel load reduction is somewhat conservative and may be loosened. The pressure pulse has significant effects on the train DOFs, and the evaluations of these safety indexes are strongly suggested in practice. The pressure pulse has a limited effect on the derailment coefficient and the lateral wheel-rail force, and, thus, their further evaluations may be not necessary.
Fermion flavor mixing in models with dynamical mass generation
Benes, Petr
2010-03-15
We present a model-independent method of dealing with fermion flavor mixing in the case when instead of constant, momentum-independent mass matrices one has rather momentum-dependent self-energies. This situation is typical for strongly coupled models of dynamical fermion mass generation. We demonstrate our approach on the example of quark mixing. We show that quark self-energies with a generic momentum dependence lead to an effective Cabibbo-Kobayashi-Maskawa matrix, which turns out to be in general nonunitary, in accordance with previous claims of other authors, and to nontrivial flavor changing electromagnetic and neutral currents. We also discuss some conceptual consequences of the momentum-dependent self-energies and show that in such a case the interaction basis and the mass basis are not related by a unitary transformation. In fact, we argue that the latter is merely an effective concept, in a specified sense. While focusing mainly on the fermionic self-energies, we also study the effects of momentum-dependent radiative corrections to the gauge bosons and to the proper vertices. Our approach is based on an application of the Lehmann-Symanzik-Zimmermann reduction formula and for the special case of constant self-energies it gives the same results as the standard approach based on the diagonalization of mass matrices.
Dynamic conversion of solar generated heat to electricity
NASA Technical Reports Server (NTRS)
Powell, J. C.; Fourakis, E.; Hammer, J. M.; Smith, G. A.; Grosskreutz, J. C.; Mcbride, E.
1974-01-01
The effort undertaken during this program led to the selection of the water-superheated steam (850 psig/900 F) crescent central receiver as the preferred concept from among 11 candidate systems across the technological spectrum of the dynamic conversion of solar generated heat to electricity. The solar power plant designs were investigated in the range of plant capacities from 100 to 1000 Mw(e). The investigations considered the impacts of plant size, collector design, feed-water temperature ratio, heat rejection equipment, ground cover, and location on solar power technical and economic feasibility. For the distributed receiver systems, the optimization studies showed that plant capacities less than 100 Mw(e) may be best. Although the size of central receiver concepts was not parametrically investigated, all indications are that the optimal plant capacity for central receiver systems will be in the range from 50 to 200 Mw(e). Solar thermal power plant site selection criteria and methodology were also established and used to evaluate potentially suitable sites. The result of this effort was to identify a site south of Inyokern, California, as typically suitable for a solar thermal power plant. The criteria used in the selection process included insolation and climatological characteristics, topography, and seismic history as well as water availability.
Study of a possible S = + 1 dynamically generated baryonic resonance
NASA Astrophysics Data System (ADS)
Sarkar, Sourav; Oset, E.; Vicente Vacas, M. J.
2005-05-01
Starting from the lowest-order chiral Lagrangian for the interaction of the baryon decuplet with the octet of pseudoscalar mesons we find an attractive interaction in the ΔK channel with L = 0 and I = 1, while the interaction is repulsive for I = 2. The attractive interaction leads to a pole in the second Riemann sheet of the complex plane and manifests itself in a large strength of the ΔK scattering amplitude close to the ΔK threshold, which is not the case for I = 2. However, we also make a study of uncertainties in the model and conclude that the existence of this pole depends sensitively upon the input used and can disappear within reasonable variations of the input parameters. We take advantage to study the stability of the other poles obtained for the {{3}/{2}}- dynamically generated resonances of the model and conclude that they are stable and not contingent to reasonable changes in the input of the theory.
Dynamic airspace configuration algorithms for next generation air transportation system
NASA Astrophysics Data System (ADS)
Wei, Jian
The National Airspace System (NAS) is under great pressure to safely and efficiently handle the record-high air traffic volume nowadays, and will face even greater challenge to keep pace with the steady increase of future air travel demand, since the air travel demand is projected to increase to two to three times the current level by 2025. The inefficiency of traffic flow management initiatives causes severe airspace congestion and frequent flight delays, which cost billions of economic losses every year. To address the increasingly severe airspace congestion and delays, the Next Generation Air Transportation System (NextGen) is proposed to transform the current static and rigid radar based system to a dynamic and flexible satellite based system. New operational concepts such as Dynamic Airspace Configuration (DAC) have been under development to allow more flexibility required to mitigate the demand-capacity imbalances in order to increase the throughput of the entire NAS. In this dissertation, we address the DAC problem in the en route and terminal airspace under the framework of NextGen. We develop a series of algorithms to facilitate the implementation of innovative concepts relevant with DAC in both the en route and terminal airspace. We also develop a performance evaluation framework for comprehensive benefit analyses on different aspects of future sector design algorithms. First, we complete a graph based sectorization algorithm for DAC in the en route airspace, which models the underlying air route network with a weighted graph, converts the sectorization problem into the graph partition problem, partitions the weighted graph with an iterative spectral bipartition method, and constructs the sectors from the partitioned graph. The algorithm uses a graph model to accurately capture the complex traffic patterns of the real flights, and generates sectors with high efficiency while evenly distributing the workload among the generated sectors. We further improve
Lewan, M.D.; Ruble, T.E.
2002-01-01
This study compares kinetic parameters determined by open-system pyrolysis and hydrous pyrolysis using aliquots of source rocks containing different kerogen types. Kinetic parameters derived from these two pyrolysis methods not only differ in the conditions employed and products generated, but also in the derivation of the kinetic parameters (i.e., isothermal linear regression and non-isothermal nonlinear regression). Results of this comparative study show that there is no correlation between kinetic parameters derived from hydrous pyrolysis and open-system pyrolysis. Hydrous-pyrolysis kinetic parameters determine narrow oil windows that occur over a wide range of temperatures and depths depending in part on the organic-sulfur content of the original kerogen. Conversely, open-system kinetic parameters determine broad oil windows that show no significant differences with kerogen types or their organic-sulfur contents. Comparisons of the kinetic parameters in a hypothetical thermal-burial history (2.5 ??C/my) show open-system kinetic parameters significantly underestimate the extent and timing of oil generation for Type-US kerogen and significantly overestimate the extent and timing of petroleum formation for Type-I kerogen compared to hydrous pyrolysis kinetic parameters. These hypothetical differences determined by the kinetic parameters are supported by natural thermal-burial histories for the Naokelekan source rock (Type-IIS kerogen) in the Zagros basin of Iraq and for the Green River Formation (Type-I kerogen) in the Uinta basin of Utah. Differences in extent and timing of oil generation determined by open-system pyrolysis and hydrous pyrolysis can be attributed to the former not adequately simulating natural oil generation conditions, products, and mechanisms.
Wormhoudt, J.; Yousefian, V.; Weinberg, M.; Kolb, C.; Martinez-Sanchez, M.; Cheng, W.; Dvore, D.; Freedman, A.; Stanton, A.; Stewart, G.
1981-05-01
The successful design of full-scale, open-cycle, coal-fired MHD generators for baseload electrical production requires a detailed understanding of the plasma chemical and plasma dynamic characteristics of anticipated combustor and channel fluids. Progress in efforts to model the efficiency of an open-cycle, coal-fired MHD channel based on the characterization of the channel flow as well as laboratory experiments to validate the modeling effort is reported. In addition, studies related to understanding arcing and corrosion phenomena in the vicinity of an anode are reported.
Wormhoudt, J.; Yousefian, V.; Weinberg, M.; Kolb, C.; Martinez-Sanchez, M.; Cheng, W.; Bien, F.; Dvore, D.; Unkel, W.; Stewart, G.
1980-09-01
The successful design of full-scale, open-cycle, coal-fired MHD generators for baseload electrical production requires a detailed understanding of the plasma chemical and plasma dynamic characteristics of anticipated combustor and channel fluids. Progress in efforts to model the efficiency of an open-cycle, coal-fired MHD channel based on the characterization of the channel flow as well as laboratory experiments to validate the modeling effort as detailed. In addition, studies related to understanding arcing phenomena in the vicinity of an anode are reported.
Web-based Toolkit for Dynamic Generation of Data Processors
NASA Astrophysics Data System (ADS)
Patel, J.; Dascalu, S.; Harris, F. C.; Benedict, K. K.; Gollberg, G.; Sheneman, L.
2011-12-01
All computation-intensive scientific research uses structured datasets, including hydrology and all other types of climate-related research. When it comes to testing their hypotheses, researchers might use the same dataset differently, and modify, transform, or convert it to meet their research needs. Currently, many researchers spend a good amount of time performing data processing and building tools to speed up this process. They might routinely repeat the same process activities for new research projects, spending precious time that otherwise could be dedicated to analyzing and interpreting the data. Numerous tools are available to run tests on prepared datasets and many of them work with datasets in different formats. However, there is still a significant need for applications that can comprehensively handle data transformation and conversion activities and help prepare the various processed datasets required by the researchers. We propose a web-based application (a software toolkit) that dynamically generates data processors capable of performing data conversions, transformations, and customizations based on user-defined mappings and selections. As a first step, the proposed solution allows the users to define various data structures and, in the next step, can select various file formats and data conversions for their datasets of interest. In a simple scenario, the core of the proposed web-based toolkit allows the users to define direct mappings between input and output data structures. The toolkit will also support defining complex mappings involving the use of pre-defined sets of mathematical, statistical, date/time, and text manipulation functions. Furthermore, the users will be allowed to define logical cases for input data filtering and sampling. At the end of the process, the toolkit is designed to generate reusable source code and executable binary files for download and use by the scientists. The application is also designed to store all data
Self-generated overvoltages due to open-phasing of ungrounded-wye delta transformer banks
Walling, R.A.; Hartana, R.K.; Ros, W.J.
1994-12-31
Disconnecting one phase of an ungrounded-wye delta transformer bank from the source can result in severe overvoltages due to neutral shift and ferroresonance. Neutral shift overvoltages are quantified and their impact on metal-oxide surge arresters are evaluated. Ferroresonance is shown by test data to occur when low-loss banks, 15 kV and higher, are open phased. Design and operating practices to eliminate or mitigate these self-generated overvoltages are discussed.
Self-generated overvoltages due to open-phasing of ungrounded-wye delta transformer banks
Walling, R.A.; Hartana, R.K.; Ros, W.J.
1995-01-01
Disconnecting one phase of an ungrounded-wye delta transformer bank from the source can result In severe overvoltages due to neutral shirt and ferroresonance. Neutral shirt overvoltages are quantified and their Impact on metal-oxide surge arresters are evaluated. Ferroresonance is shown by test data to occur when low-loss banks, 15 kV and higher, are open phased. Design and operating practices to eliminate or mitigate these self-generated overvoltages are discussed.
NGSView: an extensible open source editor for next-generation sequencing data
Arner, Erik; Hayashizaki, Yoshihide; Daub, Carsten O.
2010-01-01
Summary:High-throughput sequencing technologies introduce novel demands on tools available for data analysis. We have developed NGSView (Next Generation Sequence View), a generally applicable, flexible and extensible next-generation sequence alignment editor. The software allows for visualization and manipulation of millions of sequences simultaneously on a desktop computer, through a graphical interface. NGSView is available under an open source license and can be extended through a well documented API. Availability: http://ngsview.sourceforge.net Contact: arner@gsc.riken.jp PMID:19855106
Asymmetric exclusion process with a dynamic roadblock and open boundaries
NASA Astrophysics Data System (ADS)
Sahoo, Mamata; Klumpp, Stefan
2016-08-01
Motivated by complex transport processes occurring in nature, we study a totally asymmetric simple exclusion process (TASEP) with a dynamic ‘roadblock’ particle. The roadblock particle blocks the traffic of moving particles while bound to the lattice, but can stochastically unbind or switch off, thus enabling the traffic to pass. We use simulations to study the dependence of the particle flux on the on/off switching dynamics of the roadblock, which exhibits a surprisingly rich dynamic behaviour. In particular, unlike in other studied TASEP variants with defects, here we observe that the particle flux is affected by the roadblock even in the initiation-limited or low density phase if the roadblock dynamics is slow. Rapid switching off the roadblock results in the typical behaviour of a TASEP with a defect/pause with reduced maximal current, but no effect of the roadblock on the flux in the initiation-limited phase. Moreover, in an intermediate range of roadblock rates, the particle current is found to be system-size dependent.
Definition phase for thermal ion dynamics experiment for OPEN
NASA Technical Reports Server (NTRS)
Sharp, W. E.
1985-01-01
The Thermal Ion Dynamics Experiment (TIDE) combines differential measurements of angle, energy, and mass to determine the detailed distribution function of low energy magnetospheric ions in the range of 0 to 100 eV. Goals included designing a 1 sq cm entrance aperture, minimizing trajectory divergence at exist aperture, and minimizing internal scattering. Design parameters were used to construct the test model.
Dynamic federations: storage aggregation using open tools and protocols
NASA Astrophysics Data System (ADS)
Furano, Fabrizio; Brito da Rocha, Ricardo; Devresse, Adrien; Keeble, Oliver; Álvarez Ayllón, Alejandro; Fuhrmann, Patrick
2012-12-01
A number of storage elements now offer standard protocol interfaces like NFS 4.1/pNFS and WebDAV, for access to their data repositories, in line with the standardization effort of the European Middleware Initiative (EMI). Also the LCG FileCatalogue (LFC) can offer such features. Here we report on work that seeks to exploit the federation potential of these protocols and build a system that offers a unique view of the storage and metadata ensemble and the possibility of integration of other compatible resources such as those from cloud providers. The challenge, here undertaken by the providers of dCache and DPM, and pragmatically open to other Grid and Cloud storage solutions, is to build such a system while being able to accommodate name translations from existing catalogues (e.g. LFCs), experiment-based metadata catalogues, or stateless algorithmic name translations, also known as “trivial file catalogues”. Such so-called storage federations of standard protocols-based storage elements give a unique view of their content, thus promoting simplicity in accessing the data they contain and offering new possibilities for resilience and data placement strategies. The goal is to consider HTTP and NFS4.1-based storage elements and metadata catalogues and make them able to cooperate through an architecture that properly feeds the redirection mechanisms that they are based upon, thus giving the functionalities of a “loosely coupled” storage federation. One of the key requirements is to use standard clients (provided by OS'es or open source distributions, e.g. Web browsers) to access an already aggregated system; this approach is quite different from aggregating the repositories at the client side through some wrapper API, like for instance GFAL, or by developing new custom clients. Other technical challenges that will determine the success of this initiative include performance, latency and scalability, and the ability to create worldwide storage federations that
Pore opening dynamics in the exocytosis of serotonin
NASA Astrophysics Data System (ADS)
Ramirez-Santiago, Guillermo; Cercos, Montserrat G.; Martinez-Valencia, Alejandro; Salinas Hernandez, Israel; Rodríguez-Sosa, Leonardo; de-Miguel, Francisco F.
2015-03-01
The current view of the exocytosis of transmitter molecules is that it starts with the formation of a fusion pore that connects the intravesicular and the extracellular spaces, and is completed by the release of the rest of the transmitter contained in the vesicle upon the full fusion and collapse of the vesicle with the plasma membrane. However, under certain circumstances, a rapid closure of the pore before the full vesicle fusion produces only a partial release of the transmitter. Here we show that whole release of the transmitter occurs through fusion pores that remain opened for tens of milliseconds without vesicle collapse. This was demonstrated through amperometric measurements of serotonin release from electrodense vesicles in the axon of leech Retzius neurons and mathematical modelling. By modeling transmitter release with a diffusion equation subjected to boundary conditions that are defined by the experiment, we showed that those pores with a fast half rise time constant remained opened and allowed the full quantum release without vesicle collapse, whereas pores with a slow rise time constant closed rapidly, thus producing partial release. We conclude that a full transmitter release may occur through the fusion pore in the absence of vesicle collapse. This work was founded by a DGAPA-UNAM grants IN200914 and IN118410 CONACYT GRANT 130031, and CONACyT doctoral fellowships.
Dynamic Simulation over Long Time Periods with 100% Solar Generation.
Concepcion, Ricky James; Elliott, Ryan Thomas
2015-12-01
This project aimed to identify the path forward for dynamic simulation tools to accommodate these needs by characterizing the properties of power systems (with high PV penetration), analyzing how these properties affect dynamic simulation software, and offering solutions for potential problems.
Dynamical Interactions Make Hot Jupiters in Open Star Clusters
NASA Astrophysics Data System (ADS)
Shara, Michael M.; Hurley, Jarrod R.; Mardling, Rosemary A.
2016-01-01
Explaining the origin and evolution of exoplanetary hot Jupiters remains a significant challenge. One possible mechanism for the production of hot Jupiters is planet-planet interactions, which produce them from planets born far from their host stars but near their dynamical stability limits. In the much more likely case of planets born far from their dynamical stability limits, can hot Jupiters be formed in star clusters? Our N-body simulations answer this question in the affirmative, and show that hot Jupiter formation is not a rare event, occurring in ˜1% of star cluster planetary systems. We detail three case studies of the dynamics-induced births of hot Jupiters on highly eccentric orbits that can only occur inside star clusters. The hot Jupiters’ orbits bear remarkable similarities to those of some of the most extreme exoplanets known: HAT-P-32b, HAT-P-2b, HD 80606b, and GJ 876d. If stellar perturbations formed these hot Jupiters, then our simulations predict that these very hot inner planets are often accompanied by much more distant gas giants in highly eccentric orbits.
A Tesla-pulse forming line-plasma opening switch pulsed power generator
NASA Astrophysics Data System (ADS)
Novac, B. M.; Kumar, R.; Smith, I. R.
2010-10-01
A pulsed power generator based on a high-voltage Tesla transformer which charges a 3.85 Ω/55 ns water-filled pulse forming line to 300 kV has been developed at Loughborough University as a training tool for pulsed power students. The generator uses all forms of insulation specific to pulsed power technology, liquid (oil and water), gas (SF6), and magnetic insulation in vacuum, and a number of fast voltage and current sensors are implemented for diagnostic purposes. A miniature (centimeter-size) plasma opening switch has recently been coupled to the output of the pulse forming line, with the overall system comprising the first phase of a program aimed at the development of a novel repetitive, table-top generator capable of producing 15 GW pulses for high power microwave loads. Technical details of all the generator components and the main experimental results obtained during the program and demonstrations of their performance are presented in the paper, together with a description of the various diagnostic tools involved. In particular, it is shown that the miniature plasma opening switch is capable of reducing the rise time of the input current while significantly increasing the load power. Future plans are outlined in the conclusions.
A Tesla-pulse forming line-plasma opening switch pulsed power generator.
Novac, B M; Kumar, R; Smith, I R
2010-10-01
A pulsed power generator based on a high-voltage Tesla transformer which charges a 3.85 Ω/55 ns water-filled pulse forming line to 300 kV has been developed at Loughborough University as a training tool for pulsed power students. The generator uses all forms of insulation specific to pulsed power technology, liquid (oil and water), gas (SF(6)), and magnetic insulation in vacuum, and a number of fast voltage and current sensors are implemented for diagnostic purposes. A miniature (centimeter-size) plasma opening switch has recently been coupled to the output of the pulse forming line, with the overall system comprising the first phase of a program aimed at the development of a novel repetitive, table-top generator capable of producing 15 GW pulses for high power microwave loads. Technical details of all the generator components and the main experimental results obtained during the program and demonstrations of their performance are presented in the paper, together with a description of the various diagnostic tools involved. In particular, it is shown that the miniature plasma opening switch is capable of reducing the rise time of the input current while significantly increasing the load power. Future plans are outlined in the conclusions. PMID:21034107
Global Dynamic Exposure and the OpenBuildingMap
NASA Astrophysics Data System (ADS)
Schorlemmer, D.; Beutin, T.; Hirata, N.; Hao, K. X.; Wyss, M.; Cotton, F.; Prehn, K.
2015-12-01
Detailed understanding of local risk factors regarding natural catastrophes requires in-depth characterization of the local exposure. Current exposure capture techniques have to find the balance between resolution and coverage. We aim at bridging this gap by employing a crowd-sourced approach to exposure capturing focusing on risk related to earthquake hazard. OpenStreetMap (OSM), the rich and constantly growing geographical database, is an ideal foundation for us. More than 2.5 billion geographical nodes, more than 150 million building footprints (growing by ~100'000 per day), and a plethora of information about school, hospital, and other critical facility locations allow us to exploit this dataset for risk-related computations. We will harvest this dataset by collecting exposure and vulnerability indicators from explicitly provided data (e.g. hospital locations), implicitly provided data (e.g. building shapes and positions), and semantically derived data, i.e. interpretation applying expert knowledge. With this approach, we can increase the resolution of existing exposure models from fragility classes distribution via block-by-block specifications to building-by-building vulnerability. To increase coverage, we will provide a framework for collecting building data by any person or community. We will implement a double crowd-sourced approach to bring together the interest and enthusiasm of communities with the knowledge of earthquake and engineering experts. The first crowd-sourced approach aims at collecting building properties in a community by local people and activists. This will be supported by tailored building capture tools for mobile devices for simple and fast building property capturing. The second crowd-sourced approach involves local experts in estimating building vulnerability that will provide building classification rules that translate building properties into vulnerability and exposure indicators as defined in the Building Taxonomy 2.0 developed
On the generation of flight dynamics aerodynamic tables by computational fluid dynamics
NASA Astrophysics Data System (ADS)
Da Ronch, A.; Ghoreyshi, M.; Badcock, K. J.
2011-11-01
An approach for the generation of aerodynamic tables using computational fluid dynamics is discussed. For aircraft flight dynamics, forces and moments are often tabulated in multi-dimensional look-up tables, requiring a large number of calculations to fill the tables. A method to efficiently reduce the number of high-fidelity analyses is reviewed. The method uses a kriging-based surrogate model. Low-fidelity (computationally cheap) estimates are augmented with higher fidelity data. Data fusion combines the two datasets into one single database. The approach can also handle changes in aircraft geometry. Once constructed, the look-up tables can be used in real-time to fly the aircraft through the database. To demonstrate the capabilities of the framework presented, five test cases are considered. These include a transonic cruiser concept design, an unconventional configuration, two passenger jet aircraft, and a jet trainer aircraft. Investigations into the areas of flight handling qualities, stability and control characteristics and manoeuvring aircraft are made. To assess the accuracy of the simulations, numerical results are also compared with wind tunnel and flight test data.
Molina, Martin; Sanchez-Soriano, Javier; Corcho, Oscar
2015-01-01
Providing descriptions of isolated sensors and sensor networks in natural language, understandable by the general public, is useful to help users find relevant sensors and analyze sensor data. In this paper, we discuss the feasibility of using geographic knowledge from public databases available on the Web (such as OpenStreetMap, Geonames, or DBpedia) to automatically construct such descriptions. We present a general method that uses such information to generate sensor descriptions in natural language. The results of the evaluation of our method in a hydrologic national sensor network showed that this approach is feasible and capable of generating adequate sensor descriptions with a lower development effort compared to other approaches. In the paper we also analyze certain problems that we found in public databases (e.g., heterogeneity, non-standard use of labels, or rigid search methods) and their impact in the generation of sensor descriptions. PMID:26151211
Molina, Martin; Sanchez-Soriano, Javier; Corcho, Oscar
2015-01-01
Providing descriptions of isolated sensors and sensor networks in natural language, understandable by the general public, is useful to help users find relevant sensors and analyze sensor data. In this paper, we discuss the feasibility of using geographic knowledge from public databases available on the Web (such as OpenStreetMap, Geonames, or DBpedia) to automatically construct such descriptions. We present a general method that uses such information to generate sensor descriptions in natural language. The results of the evaluation of our method in a hydrologic national sensor network showed that this approach is feasible and capable of generating adequate sensor descriptions with a lower development effort compared to other approaches. In the paper we also analyze certain problems that we found in public databases (e.g., heterogeneity, non-standard use of labels, or rigid search methods) and their impact in the generation of sensor descriptions. PMID:26151211
Molecular dynamics study of the opening mechanism for DNA polymerase I.
Miller, Bill R; Parish, Carol A; Wu, Eugene Y
2014-12-01
During DNA replication, DNA polymerases follow an induced fit mechanism in order to rapidly distinguish between correct and incorrect dNTP substrates. The dynamics of this process are crucial to the overall effectiveness of catalysis. Although X-ray crystal structures of DNA polymerase I with substrate dNTPs have revealed key structural states along the catalytic pathway, solution fluorescence studies indicate that those key states are populated in the absence of substrate. Herein, we report the first atomistic simulations showing the conformational changes between the closed, open, and ajar conformations of DNA polymerase I in the binary (enzyme:DNA) state to better understand its dynamics. We have applied long time-scale, unbiased molecular dynamics to investigate the opening process of the fingers domain in the absence of substrate for B. stearothermophilis DNA polymerase in silico. These simulations are biologically and/or physiologically relevant as they shed light on the transitions between states in this important enzyme. All closed and ajar simulations successfully transitioned into the fully open conformation, which is known to be the dominant binary enzyme-DNA conformation from solution and crystallographic studies. Furthermore, we have detailed the key stages in the opening process starting from the open and ajar crystal structures, including the observation of a previously unknown key intermediate structure. Four backbone dihedrals were identified as important during the opening process, and their movements provide insight into the recognition of dNTP substrate molecules by the polymerase binary state. In addition to revealing the opening mechanism, this study also demonstrates our ability to study biological events of DNA polymerase using current computational methods without biasing the dynamics. PMID:25474643
NASA Astrophysics Data System (ADS)
Stella, L.; Lorenz, C. D.; Kantorovich, L.
2014-04-01
The generalized Langevin equation (GLE) has been recently suggested to simulate the time evolution of classical solid and molecular systems when considering general nonequilibrium processes. In this approach, a part of the whole system (an open system), which interacts and exchanges energy with its dissipative environment, is studied. Because the GLE is derived by projecting out exactly the harmonic environment, the coupling to it is realistic, while the equations of motion are non-Markovian. Although the GLE formalism has already found promising applications, e.g., in nanotribology and as a powerful thermostat for equilibration in classical molecular dynamics simulations, efficient algorithms to solve the GLE for realistic memory kernels are highly nontrivial, especially if the memory kernels decay nonexponentially. This is due to the fact that one has to generate a colored noise and take account of the memory effects in a consistent manner. In this paper, we present a simple, yet efficient, algorithm for solving the GLE for practical memory kernels and we demonstrate its capability for the exactly solvable case of a harmonic oscillator coupled to a Debye bath.
Dynamics and Power Generation Potential from a Tethered Kite Moving in a Horizontal Flightpath
NASA Astrophysics Data System (ADS)
Gavi, Glenn Romo
Tethered-wing power systems are a viable possibility for collecting energy from stronger, more consistent winds found in the upper regions of the atmosphere where conventional wind turbines are incapable of reaching. To date, all of the tethered-wing systems fly with the tether oriented down-wind of the ground attachment point. Examined here are the dynamics and performance of a novel system where the tether is oriented both upwind and downwind of the ground attachment point during normal operation of the device. Certain prototypes built by Makani and Ampyx Power are considered to have motions analogous to the motions of the blade tips on conventional horizontal-axis wind turbines. If true, this system has motions that are analogous to conventional vertical-axis wind turbines. The system has a ground-based generator which is mechanical coupled to the aircraft and energy is generated on the reel-out phase of each cycle while a smaller amount of energy is consumed during the reel-in phase of each cycle. A simple model was developed which captures the dominant dynamics of this system and shows, via simulation, that the proposed system is viable and capable of stable and unstable periodic motions with a simulated closed-loop tether tension controller or a simple open loop reel-rate controller. In addition, it is capable of motions which produce net positive power. The small system examined, where parameter optimization was not performed, predicts an average cycle power of more than 500 watts in a 10 m/s wind.
Non-markovian mesoscopic dissipative dynamics of open quantum spin chains
NASA Astrophysics Data System (ADS)
Benatti, F.; Carollo, F.; Floreanini, R.; Narnhofer, H.
2016-01-01
We study the dissipative dynamics of N quantum spins with Lindblad generator consisting of operators scaling as fluctuations, namely with the inverse square-root of N. In the large N limit, the microscopic dissipative time-evolution converges to a non-Markovian unitary dynamics on strictly local operators, while at the mesoscopic level of fluctuations it gives rise to a dissipative non-Markovian dynamics. The mesoscopic time-evolution is Gaussian and exhibits either a stable or an unstable asymptotic character; furthermore, the mesoscopic dynamics builds correlations among fluctuations that survive in time even when the original microscopic dynamics is unable to correlate local observables.
Using Automated Code Generation to Support High Performance Extended MHD Integration in OpenGGCM
NASA Astrophysics Data System (ADS)
Germaschewski, K.; Raeder, J.
2011-10-01
Automatic code generation is a technique that takes the specification of an algorithm at a high abstraction level and turns it into a well-tuned computer code. For finite-volume / finite-difference based discretizations, this higher abstraction level can be a stencil computation. At the backend, the code generator features modules which generate optimal code for specific hardware architectures, for example conventional architectures (x86) using SIMD instructions (e.g. SSE2), or heterogeneous architectures like the Cell processor or GPGPUs. The definition of the computation is agnostic to the actual hardware used, as a high-performance implementation tailored to the specific architecture will be generated automatically. The OpenGGCM code, a global magnetosphere model, has been converted to use an automatically generated implementation of its magnetohydrodynamics (MHD) integrator. The new version enables us to take advantage of the Cell processor's computational capability and also shows performance improvements of up to 2.3× on a conventional Intel processor. The code generation approach also facilitated the recent extension of the MHD model to incorporate Hall physics.
Non-Markovian dynamics of open quantum systems
NASA Astrophysics Data System (ADS)
Fleming, Chris H.
An open quantum system is a quantum system that interacts with some environment whose degrees of freedom have been coarse grained away. This model describes non-equilibrium processes more general than scattering-matrix formulations. Furthermore, the microscopically-derived environment provides a model of noise, dissipation and decoherence far more general than Markovian (white noise) models. The latter are fully characterized by Lindblad equations and can be motivated phenomenologically. Non-Markovian processes consistently account for backreaction with the environment and can incorporate effects such as finite temperature and spatial correlations. We consider linear systems with bilinear coupling to the environment, or quantum Brownian motion, and nonlinear systems with weak coupling to the environment. For linear systems we provide exact solutions with analytical results for a variety of spectral densities. Furthermore, we point out an important mathematical subtlety which led to incorrect master-equation coefficients in earlier derivations, given nonlocal dissipation. For nonlinear systems we provide perturbative solutions by translating the formalism of canonical perturbation theory into the context of master equations. It is shown that unavoidable degeneracy causes an unfortunate reduction in accuracy between perturbative master equations and their solutions. We also extend the famous theorem of Lindblad, Gorini, Kossakowski and Sudarshan on completely positivity to non-Markovian master equations. Our application is primarily to model atoms interacting via a common electromagnetic field. The electromagnetic field contains correlations in both space and time, which are related to its relativistic (photon-mediated) nature. As such, atoms residing in the same field experience different environmental effects depending upon their relative position and orientation. Our more accurate solutions were necessary to assess sudden death of entanglement at zero temperature
NASA Astrophysics Data System (ADS)
Li, Faqi; Song, Dan; Zeng, Deping; Lin, Zhou; He, Min; Lei, Guangrong; Wu, Junru; Zhang, Dong; Wang, Zhibiao
2015-12-01
Resolution of high intensity focused ultrasound (HIFU) focusing is limited by the wave diffraction. We have developed a spherical cavity transducer with two open ends to improve the focusing precision without sacrificing the acoustic intensity (App Phys Lett 2013; 102: 204102). This work aims to theoretically and experimentally investigate the frequency dependence of the acoustic field generated from the spherical cavity transducer with two open ends. The device emits high intensity ultrasound at the frequency ranging from 420 to 470 kHz, and the acoustic field is measured by a fiber optic probe hydrophone. The measured results shows that the spherical cavity transducer provides high acoustic intensity for HIFU treatment only in its resonant modes, and a series of resonant frequencies can be choosen. Furthermore, a finite element model is developed to discuss the frequency dependence of the acoustic field. The numerical simulations coincide well with the measured results.
Li, Faqi; Zeng, Deping; He, Min; Wang, Zhibiao E-mail: wangzhibiao@haifu.com.cn; Song, Dan; Lei, Guangrong; Lin, Zhou; Zhang, Dong E-mail: wangzhibiao@haifu.com.cn; Wu, Junru
2015-12-15
Resolution of high intensity focused ultrasound (HIFU) focusing is limited by the wave diffraction. We have developed a spherical cavity transducer with two open ends to improve the focusing precision without sacrificing the acoustic intensity (App Phys Lett 2013; 102: 204102). This work aims to theoretically and experimentally investigate the frequency dependence of the acoustic field generated from the spherical cavity transducer with two open ends. The device emits high intensity ultrasound at the frequency ranging from 420 to 470 kHz, and the acoustic field is measured by a fiber optic probe hydrophone. The measured results shows that the spherical cavity transducer provides high acoustic intensity for HIFU treatment only in its resonant modes, and a series of resonant frequencies can be choosen. Furthermore, a finite element model is developed to discuss the frequency dependence of the acoustic field. The numerical simulations coincide well with the measured results.
Demographic heterogeneity and the dynamics of open populations.
Noonburg, Erik G; Chen, Adam; Shima, Jeffrey S; Swearer, Stephen E
2015-05-01
Individuals vary in their phenotype and propensity for growth and survival, but the demographic consequences of this remain poorly understood. We extend previous theoretical work on benthic marine populations and formulate a new model to evaluate how demographic heterogeneity among newly settled reef fish affects population stability. We simulated settlement, growth, and mortality of a small reef fish, the common triplefin (Forsterygion lapillurn) in an open "subpopulation" using a delay-differential equation model framework. We modeled demographic heterogeneity with a discrete number of "quality" types, motivated by our previous empirical observations: individuals were either "high quality" (immigrants from nearby subpopulations) or "low quality" (immigrants from distant subpopulations); in our model, quality influences how quickly individuals develop at a given competitor density. Our results demonstrate how demographic heterogeneity and juvenile competition interact to qualitatively alter the effects of settlement on population stability. Specifically, our model suggests that a mixture of quality types can stabilize the equilibrium even when equal settlement of either type alone would result in an unstable equilibrium. These results highlight the importance of among-individual variation in a metapopulation context, and suggest that in systems where dispersal influences individual quality, connectivity may serve to stabilize local populations. PMID:26236830
Pettitt, M.R.
1985-08-01
The report presents the results of an extensive research and development program to reduce the noise generated during coal cutting. The characteristics and magnitude of continuous miner coal-cutting noise sources are defined. This work consisted of development of a simulated coal seam to facilitate above-ground coal cutting tests, noise measurements in a reverberant acoustic chamber during simulated mining operations of a continuous miner (cutting the simulated coal seam), and noise measurements in an underground coal mine during continuous miner operation. Methods to reduce coal cutting noise are presented. These methods take full advantage of the dynamic characteristics of the forces generated during coal cutting. Dynamic cutting force isolation was shown to be a very effective technique.
NASA Astrophysics Data System (ADS)
Bao, Chengying; Xiao, Xiaosheng; Yang, Changxi
2013-05-01
We suggest a scheme to manipulate the generation dynamics of high-Q microresonator-based frequency combs (microcombs). Our simulation demonstrates that a certain subfamily of comb teeth can be suppressed via selectively filtering out limited modes, from which high-quality mode-locked pulses can be generated. Mode-pulling in microcomb generation is also analyzed quantitatively to explain the results. These results can help us better understand microcomb generation dynamics and will be beneficial in controlling the generated comb line number and spacing.
Alpha-canonical form representation of the open loop dynamics of the Space Shuttle main engine
NASA Technical Reports Server (NTRS)
Duyar, Almet; Eldem, Vasfi; Merrill, Walter C.; Guo, Ten-Huei
1991-01-01
A parameter and structure estimation technique for multivariable systems is used to obtain a state space representation of open loop dynamics of the space shuttle main engine in alpha-canonical form. The parameterization being used is both minimal and unique. The simplified linear model may be used for fault detection studies and control system design and development.
Collaborative Learning: The Effects of Trust and Open and Closed Dynamics on Consensus and Efficacy
ERIC Educational Resources Information Center
Harney, Owen; Hogan, Michael J.; Broome, Benjamin J.
2012-01-01
The current study compared the effects of open versus closed group dynamics on perceived consensus, objective consensus, and perceived efficacy of collaborative learning in participants high and low in dispositional trust in the context of an Interactive Management (IM) session. Interactive management is a computer-mediated collaborative tool…
Inward open characterization of EmrD transporter with molecular dynamics simulation.
Tan, Xianwei; Wang, Boxiong
2016-06-10
EmrD is a member of the multidrug resistance exporter family. Up to now, little is known about the structural dynamics that underline the function of the EmrD protein in inward-facing open state and how the EmrD transits from an occluded state to an inward open state. For the first time the article applied the AT simulation to investigate the membrane transporter protein EmrD, and described the dynamic features of the whole protein, the domain, the helices, and the amino acid residues during an inward-open process from its occluded state. The gradual inward-open process is different from the current model of rigid-body domain motion in alternating-access mechanism. Simulation results show that the EmrD inward-open conformational fluctuation propagates from a C-terminal domain to an N-terminal domain via the linker region during the transition from its occluded state. The conformational fluctuation of the C-terminal domain is larger than that of the N-terminal domain. In addition, it is observed that the helices exposed to the surrounding membrane show a higher level of flexibility than the other regions, and the protonated E227 plays a key role in the transition from the occluded to the open state. PMID:27055595
Experimental investigation of door dynamic opening caused by impinging shock wave
NASA Astrophysics Data System (ADS)
Biamino, L.; Jourdan, G.; Mariani, C.; Igra, O.; Massol, A.; Houas, L.
2011-02-01
To prevent damage caused by accidental overpressure inside a closed duct (e.g. jet engine) safety valves are introduced. The present study experimentally investigates the dynamic opening of such valves by employing a door at the end of a shock tube driven section. The door is hung on an axis and is free to rotate, thereby opening the tube. The evolved flow and wave pattern due to a collision of an incident shock wave with the door, causing the door opening, is studied by employing a high speed schlieren system and recording pressures at different places inside the tube as well as on the rotating door. Analyzing this data sheds light on the air flow evolution and the behavior of the opening door. In the present work, emphasis is given to understanding the complex, unsteady flow developed behind the transmitted shock wave as it diffracts over the opening door. It is shown that both the door inertia and the shock wave strength influence the opening dynamic evolution, but not in the proportions that might be expected.
Pseudo generators for under-resolved molecular dynamics
NASA Astrophysics Data System (ADS)
Bittracher, A.; Hartmann, C.; Junge, O.; Koltai, P.
2015-09-01
Many features of a molecule which are of physical interest (e.g. molecular conformations, reaction rates) are described in terms of its dynamics in configuration space. This article deals with the projection of molecular dynamics in phase space onto configuration space. Specifically, we study the situation that the phase space dynamics is governed by a stochastic Langevin equation and study its relation with the configurational Smoluchowski equation in the three different scaling regimes: Firstly, the Smoluchowski equations in non-Cartesian geometries are derived from the overdamped limit of the Langevin equation. Secondly, transfer operator methods are used to describe the metastable behaviour of the system at hand, and an explicit small-time asymptotics is derived on which the Smoluchowski equation turns out to govern the dynamics of the position coordinate (without any assumptions on the damping). By using an adequate reduction technique, these considerations are then extended to one-dimensional reaction coordinates. Thirdly, we sketch three different approaches to approximate the metastable dynamics based on time-local information only.
Dynamical fermion mass generation and exciton spectra in graphene
Zhang Chunxu; Liu Guozhu; Huang Mingqiu
2011-03-15
The Coulomb interaction between massless Dirac fermions may induce dynamical chiral symmetry breaking by forming excitonic pairs in clean graphene, leading to semimetal-insulator transition. If the Dirac fermions have zero bare mass, an exact continuous chiral symmetry is dynamically broken and thus there are massless Goldstone excitons. If the Dirac fermions have a small bare mass, an approximate continuous chiral symmetry is dynamically broken and the resultant Goldstone-type excitons become massive, which is analogous to what happens in QCD. In this paper, after solving the Dyson-Schwinger gap equation in the presence of a small bare fermion mass, we found a remarkable reduction of the critical Coulomb interaction strength for excitonic pair formation and a strong enhancement of dynamical fermion mass. We then calculate the masses of Goldstone-type excitons using the Shifman-Vainshtein-Zakharov sum-rule method and operator product expansion technique developed in QCD and find that the exciton masses are much larger than bare fermion mass but smaller than the width of dynamical fermion mass gap. We also study the spin susceptibilities and estimate the masses of non-Goldstone-type excitons using the same tools.
Synchronous Generator Model Parameter Estimation Based on Noisy Dynamic Waveforms
NASA Astrophysics Data System (ADS)
Berhausen, Sebastian; Paszek, Stefan
2016-01-01
In recent years, there have occurred system failures in many power systems all over the world. They have resulted in a lack of power supply to a large number of recipients. To minimize the risk of occurrence of power failures, it is necessary to perform multivariate investigations, including simulations, of power system operating conditions. To conduct reliable simulations, the current base of parameters of the models of generating units, containing the models of synchronous generators, is necessary. In the paper, there is presented a method for parameter estimation of a synchronous generator nonlinear model based on the analysis of selected transient waveforms caused by introducing a disturbance (in the form of a pseudorandom signal) in the generator voltage regulation channel. The parameter estimation was performed by minimizing the objective function defined as a mean square error for deviations between the measurement waveforms and the waveforms calculated based on the generator mathematical model. A hybrid algorithm was used for the minimization of the objective function. In the paper, there is described a filter system used for filtering the noisy measurement waveforms. The calculation results of the model of a 44 kW synchronous generator installed on a laboratory stand of the Institute of Electrical Engineering and Computer Science of the Silesian University of Technology are also given. The presented estimation method can be successfully applied to parameter estimation of different models of high-power synchronous generators operating in a power system.
Brane world generated dynamically from string type IIB matrices
Nishimura; Vernizzi
2000-11-27
We have recently proposed a dynamical mechanism that may realize a flat four-dimensional space-time as a brane in type IIB superstring theory. A crucial role is played by the phase of the chiral fermion integral associated with the IKKT (Ishibashi-Kawai-Kitazawa-Tsuchiya) matrix theory, which is conjectured to be a nonperturbative definition of type IIB superstring theory. We demonstrate our mechanism by studying a simplified model, in which we find that a lower-dimensional brane indeed appears dynamically. We also comment on some implications of our mechanism on model building of the brane world. PMID:11082622
Li, Li-Ming; Cheng, Kai; Wang, Fei; Zhang, Jian
2013-05-20
Two novel three-dimensional chiral metal phosphite open frameworks with 4-connected quartz topology, [Me2-DABCO][M2(HPO3)3] [M = Co (1), Zn (2); Me2-DABCO = N,N'-dimethyl-1,4-diazabicyclo[2.2.2]octane], have been ionothermally synthesized in deep eutectic solvents (choline chloride/1,3-dimethylurea). It is interesting that the organic template, Me2-DABCO, is in situ generated from the alkylation reaction of 1,4-diazabicyclo[2.2.2]octane and dimethyl phosphites. PMID:23621695
Combined Flux Compression and Plasma Opening Switch on the Saturn Pulsed Power Generator
Felber, Franklin S.; Waisman, Eduardo M.; Mazarakis, Michael G.
2010-05-07
A wire-array flux-compression cartridge installed on Sandia's Saturn pulsed power generator doubled the current into a 3-nH load to 6 MA and halved its rise time to 100 ns. The current into the load, however, was unexpectedly delayed by almost 1 {mu}s. Estimates of a plasma flow switch acting as a long-conduction-time opening switch are consistent with key features of the power compression. The results suggest that microsecond-conduction-time plasma flow switches can be combined with flux compression both to amplify currents and to sharpen pulse rise times in pulsed power drivers.
Canonical versus noncanonical equilibration dynamics of open quantum systems.
Yang, Chun-Jie; An, Jun-Hong; Luo, Hong-Gang; Li, Yading; Oh, C H
2014-08-01
In statistical mechanics, any quantum system in equilibrium with its weakly coupled reservoir is described by a canonical state at the same temperature as the reservoir. Here, by studying the equilibration dynamics of a harmonic oscillator interacting with a reservoir, we evaluate microscopically the condition under which the equilibration to a canonical state is valid. It is revealed that the non-Markovian effect and the availability of a stationary state of the total system play a profound role in the equilibration. In the Markovian limit, the conventional canonical state can be recovered. In the non-Markovian regime, when the stationary state is absent, the system equilibrates to a generalized canonical state at an effective temperature; whenever the stationary state is present, the equilibrium state of the system cannot be described by any canonical state anymore. Our finding of the physical condition on such noncanonical equilibration might have significant impact on statistical physics. A physical scheme based on circuit QED is proposed to test our results. PMID:25215704
Generating dynamic simulations of movement using computed muscle control.
Thelen, Darryl G; Anderson, Frank C; Delp, Scott L
2003-03-01
Computation of muscle excitation patterns that produce coordinated movements of muscle-actuated dynamic models is an important and challenging problem. Using dynamic optimization to compute excitation patterns comes at a large computational cost, which has limited the use of muscle-actuated simulations. This paper introduces a new algorithm, which we call computed muscle control, that uses static optimization along with feedforward and feedback controls to drive the kinematic trajectory of a musculoskeletal model toward a set of desired kinematics. We illustrate the algorithm by computing a set of muscle excitations that drive a 30-muscle, 3-degree-of-freedom model of pedaling to track measured pedaling kinematics and forces. Only 10 min of computer time were required to compute muscle excitations that reproduced the measured pedaling dynamics, which is over two orders of magnitude faster than conventional dynamic optimization techniques. Simulated kinematics were within 1 degrees of experimental values, simulated pedal forces were within one standard deviation of measured pedal forces for nearly all of the crank cycle, and computed muscle excitations were similar in timing to measured electromyographic patterns. The speed and accuracy of this new algorithm improves the feasibility of using detailed musculoskeletal models to simulate and analyze movement. PMID:12594980
Coherent Dynamics of Open Quantum System in the Presence of Majorana Fermions
NASA Astrophysics Data System (ADS)
Assuncao, Maryzaura O.; Diniz, Ginetom S.; Vernek, Edson; Souza, Fabricio M.
In recent years the research on quantum coherent dynamics of open systems has attracted great attention due to its relevance for future implementation of quantum computers. In the present study we apply the Kadanoff-Baym formalism to simulate the population dynamics of a double-dot molecular system attached to both a superconductor and fermionic reservoirs. We solve both analytically and numerically a set of coupled differential equations that account for crossed Andreev reflection (CAR), intramolecular hopping and tunneling. We pay particular attention on how Majorana bound states can affect the population dynamics of the molecule. We investigate on how initial state configuration affects the dynamics. For instance, if one dot is occupied and the other one is empty, the dynamics is dictated by the inter dot tunneling. On the other hand, for initially empty dots, the CAR dominates. We also investigate how the source and drain currents evolve in time. This work was supporte by FAPEMIG, CNPq and CAPES.
A semiconductor opening switch based generator with pulse repetitive frequency of 4 MHz.
Wang, Gang; Su, Jiancang; Ding, Zhenjie; Yuan, Xuelin; Pan, Yafeng
2013-12-01
A MHz repetitive and nanosecond pulsed power generator based on the semiconductor opening switch (SOS) is developed, in which the pulse compression unit utilizes several Radio Frequency (RF) MOSFETs and a saturable Linear Transformer Driver (LTD). The RF MOSFETs are employed to obtain the forward pumping current pulses with the duration of tens of nanoseconds; the saturable LTD is used to raise the pulse voltage, to compress the pulse width and to pump SOS reversely. The SOS assembly cuts off the reverse current in a few nanoseconds, leading to a narrow output pulse on an external load. The experimental results show that the amplitude of the output pulse on a 106 Ω resistive load is about 3.8 kV and the width is 2 ns. Due to the repetitive ability of the RF MOSFETs, the generator can operate at a repetitive frequency of higher than 4 MHz in burst mode. PMID:24387463
NASA Astrophysics Data System (ADS)
Fancello, A.; Bastiaans, R. J. M.; de Goey, L. P. H.
2013-10-01
This work proposes an application of the Flamelet-Generated Manifolds (FGM) technique in the OpenFOAM environment. FGM is a chemical reduced method for combustion modeling. This technique treats the combustion process as the solution of a small amount of controlling variables. Regarding laminar simulation, a progress variable and enthalpy evolution can describe satisfactorily the problem. From a turbulent point of view, FGM can be applied to LES and RANS simulations, where the subgrid chemical terms are described with a β - PDF approach. These approaches apply satisfactorily in relatively simple gases, nevertheless for hydrogen are not more valid, due to preferential diffusion effects and instability of the flame structure. The overall aim of this research is to find technical solution for hydrogen gas turbines design in the next generation of Integrated Gasification Combined Cycle (IGCC) plants.
The significance of micro-topography in generating flow structures in open channel flow
NASA Astrophysics Data System (ADS)
Hardy, R. J.
2011-12-01
This poster investigates the effect of micro-topographic roughness on the generation, evolution and dissipation of turbulent flow structures in open channel flow. Primarily, a series of flume experiment were undertaken where natural fluvial gravel was placed in a flume and water worked until a stable bed with no sediment transport was obtained. The surface topography was measured to create a digital elevation model (DEM) enabling particle size characteristics to be measured and roughness lengths to be calculated. Flow was measured, at flow Reynolds numbers over two orders of magnitude, using Particle Imaging Velocimetry at data frequencies up to 100 Hz at a spatial resolution of 2×10-3 m. The flume conditions also provided the necessary boundary conditions for Large Eddy Simulation of flow over these heterogeneous surfaces. The data generated by these two separate methodologies was analyzed through a series of approaches, and included: i) standard Reynolds decomposition to the flow fields; ii) Eulerian coherent structure detection methods based on the invariants of the velocity gradient tensor; iii) Lagrangian coherent structure identification methods based upon direct Lyapunov exponents (DLE) and; iv) Proper Orthogonal Decomposition (POD) analysis to obtain a full understanding of the turbulent flow structures. Once the LES scheme had been fully validated against the PIV data, scales of topography were removed from the DEM. The LES simulations were then recalculated to assess the influence of topography on the generation of turbulent flow structures. The results demonstrate that the generative mechanism for these bed-generated coherent flow structures are merging hairpin-type vortices that form around bed clasts and generate larger-scale roller-type structures. This mechanism of generation appears consistent over the range of Reynolds numbers but the spatial and temporal length scales appear dependent upon the bed roughness.
High-voltage pulsed generator for dynamic fragmentation of rocks
NASA Astrophysics Data System (ADS)
Kovalchuk, B. M.; Kharlov, A. V.; Vizir, V. A.; Kumpyak, V. V.; Zorin, V. B.; Kiselev, V. N.
2010-10-01
A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ˜50 ns, current amplitude of ˜6 kA with the 40 Ω active load, and ˜20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.
Meliopoulos, Sakis; Cokkinides, George; Fardanesh, Bruce; Hedrington, Clinton
2013-12-31
This is the final report for this project that was performed in the period: October1, 2009 to June 30, 2013. In this project, a fully distributed high-fidelity dynamic state estimator (DSE) that continuously tracks the real time dynamic model of a wide area system with update rates better than 60 times per second is achieved. The proposed technology is based on GPS-synchronized measurements but also utilizes data from all available Intelligent Electronic Devices in the system (numerical relays, digital fault recorders, digital meters, etc.). The distributed state estimator provides the real time model of the system not only the voltage phasors. The proposed system provides the infrastructure for a variety of applications and two very important applications (a) a high fidelity generating unit parameters estimation and (b) an energy function based transient stability monitoring of a wide area electric power system with predictive capability. Also the dynamic distributed state estimation results are stored (the storage scheme includes data and coincidental model) enabling an automatic reconstruction and “play back” of a system wide disturbance. This approach enables complete play back capability with fidelity equal to that of real time with the advantage of “playing back” at a user selected speed. The proposed technologies were developed and tested in the lab during the first 18 months of the project and then demonstrated on two actual systems, the USVI Water and Power Administration system and the New York Power Authority’s Blenheim-Gilboa pumped hydro plant in the last 18 months of the project. The four main thrusts of this project, mentioned above, are extremely important to the industry. The DSE with the achieved update rates (more than 60 times per second) provides a superior solution to the “grid visibility” question. The generator parameter identification method fills an important and practical need of the industry. The “energy function” based
Attosecond Probing of Vibrational Dynamics with High-Harmonic Generation
NASA Astrophysics Data System (ADS)
Lein, Manfred
2005-02-01
The numerical solution of the time-dependent Schrödinger equation for vibrating hydrogen molecules in few-cycle laser pulses shows that high-harmonic generation is sensitive to the laser-induced vibrational motion. More intense harmonics are generated in heavier isotopes, the difference increasing with the harmonic frequency. Analytical theory reveals a dependence of the harmonics on the vibrational autocorrelation function. With the help of a genetic algorithm, the nuclear motion can be reconstructed from the harmonic spectra with sub-fs time resolution.
Schwinger-Dyson Equations and Dynamical gluon mass generation
Aguilar, A.C.; Natale, A.A.
2004-12-02
We obtain a solution for the gluon propagador in Landau gauge within two distinct approximations for the Schwinger-Dyson equations (SDE). The first, named Mandelstam's approximation, consist in neglecting all contributions that come from fermions and ghosts fields while in the second, the ghosts fields are taken into account leading to a coupled system of integral equations. In both cases we show that a dynamical mass for the gluon propagator can arise as a solution.
A first-generation prototype dynamic residential window
Kohler, Christian; Goudey, Howdy; Arasteh, Dariush
2004-10-26
We present the concept for a ''smart'' highly efficient dynamic window that maximizes solar heat gain during the heating season and minimizes solar heat gain during the cooling season in residential buildings. We describe a prototype dynamic window that relies on an internal shade, which deploys automatically in response to solar radiation and temperature. This prototype was built at Lawrence Berkeley National Laboratory from commercially available ''off-the-shelf'' components. It is a stand-alone, standard-size product, so it can be easily installed in place of standard window products. Our design shows promise for near-term commercialization. Improving thermal performance of this prototype by incorporating commercially available highly efficient glazing technologies could result in the first window that could be suitable for use in zero-energy homes. The unit's predictable deployment of shading could help capture energy savings that are not possible with manual shading. Installation of dynamically shaded windows in the field will allow researchers to better quantify the energy effects of shades, which could lead to increased efficiency in the sizing of heating, ventilation, and air conditioning equipment for residences.
Quantum algorithm for simulating the dynamics of an open quantum system
Wang Hefeng; Ashhab, S.; Nori, Franco
2011-06-15
In the study of open quantum systems, one typically obtains the decoherence dynamics by solving a master equation. The master equation is derived using knowledge of some basic properties of the system, the environment, and their interaction: One basically needs to know the operators through which the system couples to the environment and the spectral density of the environment. For a large system, it could become prohibitively difficult to even write down the appropriate master equation, let alone solve it on a classical computer. In this paper, we present a quantum algorithm for simulating the dynamics of an open quantum system. On a quantum computer, the environment can be simulated using ancilla qubits with properly chosen single-qubit frequencies and with properly designed coupling to the system qubits. The parameters used in the simulation are easily derived from the parameters of the system + environment Hamiltonian. The algorithm is designed to simulate Markovian dynamics, but it can also be used to simulate non-Markovian dynamics provided that this dynamics can be obtained by embedding the system of interest into a larger system that obeys Markovian dynamics. We estimate the resource requirements for the algorithm. In particular, we show that for sufficiently slow decoherence a single ancilla qubit could be sufficient to represent the entire environment, in principle.
Spatio-Temporal Dynamics of Cross Polarized Wave Generation
NASA Astrophysics Data System (ADS)
Adams, Daniel; Squier, Jeff; Durfee, Charles
2009-10-01
We use time-domain Spatially and Spectrally Resolved Interferometry (SSRI) to investigate cross-polarized wave (XPW) generation in barium fluoride. We find that the XPW pulse is √3 smaller than the input in the spatiotemporal domain regardless of the input chirp. Additionally, we calculate a temporally dependent focal length resulting from the nonlinear interaction, and discuss its implications.
Plasma-wave generation in a dynamic spacetime
NASA Astrophysics Data System (ADS)
Zhang, Fan; Yang, Huan
2016-03-01
The studies on the electromagnetic counterparts to gravitational waves have largely been focusing on binary mergers containing at least one neutron star. Numerical studies have shown however, that binary black holes can also give off electromagnetic signals when immersed in magnetized plasma. I will present some analytical work that explore the underlying mechanism for generating such signals.
Drawing on Dynamic Local Knowledge through Student-Generated Photography
ERIC Educational Resources Information Center
Coles-Ritchie, Marilee; Monson, Bayley; Moses, Catherine
2015-01-01
In this research, the authors explored how teachers using student-generated photography draw on local knowledge. The study draws on the framework of funds of knowledge to highlight the assets marginalized students bring to the classroom and the need for culturally relevant pedagogy to address the needs of a diverse public school population. The…
Spardy, Lucy E.; Markin, Sergey N.; Shevtsova, Natalia A.; Prilutsky, Boris I.; Rybak, Ilya A.; Rubin, Jonathan E.
2012-01-01
Locomotion in mammals is controlled by a spinal central pattern generator (CPG) coupled to a biomechanical limb system, with afferent feedback to the spinal circuits and CPG closing the control loop. We have considered a simplified model of this system, in which the CPG establishes a rhythm when a supra-spinal activating drive is present and afferent signals from a single-joint limb feed back to affect CPG operation. Using dynamical systems methods, in a series of two papers, we analyze the mechanisms by which this model produces oscillations, and the characteristics of these oscillations, in the closed and open loop regimes. In this first paper, we analyze the phase transition mechanisms operating within the CPG and use the results to explain how afferent feedback allows oscillations to occur at a wider range of drive values to the CPG than the range over which oscillations occur in the CPG without feedback and to comment on why stronger feedback leads to faster oscillations. Linking these transitions to structure in the phase plane associated with the limb segment clarifies how increased weights of afferent feedback to the CPG can restore locomotion after removal of supra-spinal drive to simulate spinal cord injury. PMID:22058274
Spardy, Lucy E; Markin, Sergey N; Shevtsova, Natalia A; Prilutsky, Boris I; Rybak, Ilya A; Rubin, Jonathan E
2011-12-01
Locomotion in mammals is controlled by a spinal central pattern generator (CPG) coupled to a biomechanical limb system, with afferent feedback to the spinal circuits and CPG closing the control loop. We have considered a simplified model of this system, in which the CPG establishes a rhythm when a supra-spinal activating drive is present and afferent signals from a single-joint limb feed back to affect CPG operation. Using dynamical system methods, in a series of two papers we analyze the mechanisms by which this model produces oscillations, and the characteristics of these oscillations, in the closed- and open-loop regimes. In this first paper, we analyze the phase transition mechanisms operating within the CPG and use the results to explain how afferent feedback allows oscillations to occur at a wider range of drive values to the CPG than the range over which oscillations occur in the CPG without feedback, and then to comment on why stronger feedback leads to faster oscillations. Linking these transitions to structures in the phase plane associated with the limb segment clarifies how increased weights of afferent feedback to the CPG can restore locomotion after removal of supra-spinal drive to simulate spinal cord injury. PMID:22058274
NASA Astrophysics Data System (ADS)
Spardy, Lucy E.; Markin, Sergey N.; Shevtsova, Natalia A.; Prilutsky, Boris I.; Rybak, Ilya A.; Rubin, Jonathan E.
2011-10-01
Locomotion in mammals is controlled by a spinal central pattern generator (CPG) coupled to a biomechanical limb system, with afferent feedback to the spinal circuits and CPG closing the control loop. We have considered a simplified model of this system, in which the CPG establishes a rhythm when a supra-spinal activating drive is present and afferent signals from a single-joint limb feed back to affect CPG operation. Using dynamical system methods, in a series of two papers we analyze the mechanisms by which this model produces oscillations, and the characteristics of these oscillations, in the closed- and open-loop regimes. In this first paper, we analyze the phase transition mechanisms operating within the CPG and use the results to explain how afferent feedback allows oscillations to occur at a wider range of drive values to the CPG than the range over which oscillations occur in the CPG without feedback, and then to comment on why stronger feedback leads to faster oscillations. Linking these transitions to structures in the phase plane associated with the limb segment clarifies how increased weights of afferent feedback to the CPG can restore locomotion after removal of supra-spinal drive to simulate spinal cord injury.
Rotor dynamic considerations for large wind power generator systems
NASA Technical Reports Server (NTRS)
Ormiston, R. A.
1973-01-01
Successful large, reliable, low maintenance wind turbines must be designed with full consideration for minimizing dynamic response to aerodynamic, inertial, and gravitational forces. Much of existing helicopter rotor technology is applicable to this problem. Compared with helicopter rotors, large wind turbines are likely to be relatively less flexible with higher dimensionless natural frequencies. For very large wind turbines, low power output per unit weight and stresses due to gravitational forces are limiting factors. The need to reduce rotor complexity to a minimum favors the use of cantilevered (hingeless) rotor configurations where stresses are relieved by elastic deformations.
Dynamics of Cell Generation and Turnover in the Human Heart.
Bergmann, Olaf; Zdunek, Sofia; Felker, Anastasia; Salehpour, Mehran; Alkass, Kanar; Bernard, Samuel; Sjostrom, Staffan L; Szewczykowska, Mirosława; Jackowska, Teresa; Dos Remedios, Cris; Malm, Torsten; Andrä, Michaela; Jashari, Ramadan; Nyengaard, Jens R; Possnert, Göran; Jovinge, Stefan; Druid, Henrik; Frisén, Jonas
2015-06-18
The contribution of cell generation to physiological heart growth and maintenance in humans has been difficult to establish and has remained controversial. We report that the full complement of cardiomyocytes is established perinataly and remains stable over the human lifespan, whereas the numbers of both endothelial and mesenchymal cells increase substantially from birth to early adulthood. Analysis of the integration of nuclear bomb test-derived (14)C revealed a high turnover rate of endothelial cells throughout life (>15% per year) and more limited renewal of mesenchymal cells (<4% per year in adulthood). Cardiomyocyte exchange is highest in early childhood and decreases gradually throughout life to <1% per year in adulthood, with similar turnover rates in the major subdivisions of the myocardium. We provide an integrated model of cell generation and turnover in the human heart. PMID:26073943
Innovative open air brayton combined cycle systems for the next generation nuclear power plants
NASA Astrophysics Data System (ADS)
Zohuri, Bahman
The purpose of this research was to model and analyze a nuclear heated multi-turbine power conversion system operating with atmospheric air as the working fluid. The air is heated by a molten salt, or liquid metal, to gas heat exchanger reaching a peak temperature of 660 0C. The effects of adding a recuperator or a bottoming steam cycle have been addressed. The calculated results are intended to identify paths for future work on the next generation nuclear power plant (GEN-IV). This document describes the proposed system in sufficient detail to communicate a good understanding of the overall system, its components, and intended uses. The architecture is described at the conceptual level, and does not replace a detailed design document. The main part of the study focused on a Brayton --- Rankine Combined Cycle system and a Recuperated Brayton Cycle since they offer the highest overall efficiencies. Open Air Brayton power cycles also require low cooling water flows relative to other power cycles. Although the Recuperated Brayton Cycle achieves an overall efficiency slightly less that the Brayton --- Rankine Combined Cycle, it is completely free of a circulating water system and can be used in a desert climate. Detailed results of modeling a combined cycle Brayton-Rankine power conversion system are presented. The Rankine bottoming cycle appears to offer a slight efficiency advantage over the recuperated Brayton cycle. Both offer very significant advantages over current generation Light Water Reactor steam cycles. The combined cycle was optimized as a unit and lower pressure Rankine systems seem to be more efficient. The combined cycle requires a lot less circulating water than current power plants. The open-air Brayton systems appear to be worth investigating, if the higher temperatures predicted for the Next Generation Nuclear Plant do materialize.
Lange, Nicholas D.; Thomas, Rick P.; Davelaar, Eddy J.
2012-01-01
The pre-decisional process of hypothesis generation is a ubiquitous cognitive faculty that we continually employ in an effort to understand our environment and thereby support appropriate judgments and decisions. Although we are beginning to understand the fundamental processes underlying hypothesis generation, little is known about how various temporal dynamics, inherent in real world generation tasks, influence the retrieval of hypotheses from long-term memory. This paper presents two experiments investigating three data acquisition dynamics in a simulated medical diagnosis task. The results indicate that the mere serial order of data, data consistency (with previously generated hypotheses), and mode of responding influence the hypothesis generation process. An extension of the HyGene computational model endowed with dynamic data acquisition processes is forwarded and explored to provide an account of the present data. PMID:22754547
On singular probability densities generated by extremal dynamics
NASA Astrophysics Data System (ADS)
Garcia, Guilherme J. M.; Dickman, Ronald
2004-02-01
Extremal dynamics is the mechanism that drives the Bak-Sneppen model into a (self-organized) critical state, marked by a singular stationary probability density p( x). With the aim of understanding this phenomenon, we study the BS model and several variants via mean-field theory and simulation. In all cases, we find that p( x) is singular at one or more points, as a consequence of extremal dynamics. Furthermore we show that the extremal barrier xi always belongs to the ‘prohibited’ interval, in which p( x)=0. Our simulations indicate that the Bak-Sneppen universality class is robust with regard to changes in the updating rule: we find the same value for the exponent π for all variants. Mean-field theory, which furnishes an exact description for the model on a complete graph, reproduces the character of the probability distribution found in simulations. For the modified processes mean-field theory takes the form of a functional equation for p( x).
Exploring dynamical gluon mass generation in three dimensions
NASA Astrophysics Data System (ADS)
Cornwall, John M.
2016-01-01
We reexamine the d =3 dynamical gluon mass problem in pure-glue non-Abelian S U (N ) gauge theories, paying particular attention to the observed (in Landau gauge) violation of positivity for the spectral function of the gluon propagator. This is expressed as a large bulge in the propagator at small momentum, due to the d =3 avatar of asymptotic freedom. Mass is defined through m-2=Δ (p =0 ) , where Δ (p ) is the scalar function for the gluon propagator in some chosen gauge; it is not a pole mass and is generally gauge dependent, except in the gauge-invariant pinch technique (PT). We truncate the PT equations with a recently proposed method called the vertex paradigm that automatically satisfies the QED-like Ward identity relating the three-gluon PT vertex function with the PT propagator. The mass is determined by a homogeneous Bethe-Salpeter equation involving this vertex and propagator. This gap equation also encapsulates the Bethe-Salpeter equation for the massless scalar excitations, essentially Nambu-Goldstone fields, that necessarily accompany gauge-invariant gluon mass. The problem is to find a good approximate value for m and at the same time explain the bulge, which by itself leads, in the gap equation for the gluon mass, to excessively large values for the mass. Our point is not to give a high-accuracy determination of m but to clarify the way in which the propagator bulge and a fairly accurate estimate of m can coexist, and we use various approximations that illustrate the underlying mechanisms. The most critical point is to satisfy the Ward identity. In the PT we estimate a gauge-invariant dynamical gluon mass of m ≈N g2/(2.48 π ) . We translate these results to the Landau gauge using a background-quantum identity involving a dynamical quantity κ such that m =κ mL , where mL-2≡ΔL(p =0 ) . Given our estimates for m , κ , the relation is fortuitously well satisfied for S U (2 ) lattice data.
Small shape deviations causes complex dynamics in large electric generators
NASA Astrophysics Data System (ADS)
Lundström, Niklas L. P.; Grafström, Anton; Aidanpää, Jan-Olov
2014-05-01
We prove that combinations of small eccentricity, ovality and/or triangularity in the rotor and stator can produce complex whirling motions of an unbalanced rotor in large synchronous generators. It is concluded which structures of shape deviations that are more harmful, in the sense of producing complex whirling motions, than others. For each such structure, we derive simplified equations of motions from which we conclude analytically the relation between shape deviations and mass unbalance that yield non-smooth whirling motions. Finally we discuss validity of our results in the sense of modeling of the unbalanced magnetic pull force.
Dynamics of morphology-dependent resonances by openness in dielectric disks for TE polarization
Cho, Jinhang; Rim, Sunghwan; Kim, Chil-Min
2011-04-15
We have studied the parametric evolution of morphology-dependent resonances according to the change of openness in a two-dimensional dielectric microdisk for transverse-electric polarization. We found that the dynamics exhibit avoided resonance crossings between the inner and outer resonances even though the corresponding billiard is integrable. Due to these recondite avoidances, inner and outer resonances can be exchanged and the quality (Q) factor of inner resonances is strongly affected. We analyze the diverse phenomena arising from these dynamics including the avoided crossings.
Dynamical Generation of Topological Magnetic Lattices for Ultracold Atoms.
Yu, Jinlong; Xu, Zhi-Fang; Lü, Rong; You, Li
2016-04-01
We propose a scheme to dynamically synthesize a space-periodic effective magnetic field for neutral atoms by time-periodic magnetic field pulses. When atomic spin adiabatically follows the direction of the effective magnetic field, an adiabatic scalar potential together with a geometric vector potential emerges for the atomic center-of-mass motion, due to the Berry phase effect. While atoms hop between honeycomb lattice sites formed by the minima of the adiabatic potential, complex Peierls phase factors in the hopping coefficients are induced by the vector potential, and these phase factors facilitate a topological Chern insulator. With further tuning of external parameters, both a topological phase transition and topological flat bands can be achieved, highlighting realistic prospects for studying strongly correlated phenomena in this system. Our Letter presents an alternative pathway towards creating and manipulating topological states of ultracold atoms by magnetic fields. PMID:27104703
SWIFT: a dynamical model of saccade generation during reading.
Engbert, Ralf; Nuthmann, Antje; Richter, Eike M; Kliegl, Reinhold
2005-10-01
Mathematical models have become an important tool for understanding the control of eye movements during reading. Main goals of the development of the SWIFT model (R. Engbert, A. Longtin, & R. Kliegl, 2002) were to investigate the possibility of spatially distributed processing and to implement a general mechanism for all types of eye movements observed in reading experiments. The authors present an advanced version of SWIFT that integrates properties of the oculomotor system and effects of word recognition to explain many of the experimental phenomena faced in reading research. They propose new procedures for the estimation of model parameters and for the test of the model's performance. They also present a mathematical analysis of the dynamics of the SWIFT model. Finally, within this framework, they present an analysis of the transition from parallel to serial processing. PMID:16262468
Dynamical Generation of Topological Magnetic Lattices for Ultracold Atoms
NASA Astrophysics Data System (ADS)
Yu, Jinlong; Xu, Zhi-Fang; Lü, Rong; You, Li
2016-04-01
We propose a scheme to dynamically synthesize a space-periodic effective magnetic field for neutral atoms by time-periodic magnetic field pulses. When atomic spin adiabatically follows the direction of the effective magnetic field, an adiabatic scalar potential together with a geometric vector potential emerges for the atomic center-of-mass motion, due to the Berry phase effect. While atoms hop between honeycomb lattice sites formed by the minima of the adiabatic potential, complex Peierls phase factors in the hopping coefficients are induced by the vector potential, and these phase factors facilitate a topological Chern insulator. With further tuning of external parameters, both a topological phase transition and topological flat bands can be achieved, highlighting realistic prospects for studying strongly correlated phenomena in this system. Our Letter presents an alternative pathway towards creating and manipulating topological states of ultracold atoms by magnetic fields.
All-solid-state repetitive semiconductor opening switch-based short pulse generator
NASA Astrophysics Data System (ADS)
Ding, Zhenjie; Hao, Qingsong; Hu, Long; Su, Jiancang; Liu, Guozhi
2009-09-01
The operating characteristics of a semiconductor opening switch (SOS) are determined by its pumping circuit parameters. SOS is still able to cut off the current when pumping current duration falls to the order of tens of nanoseconds and a short pulse forms simultaneously in the output load. An all-solid-state repetitive SOS-based short pulse generator (SPG100) with a three-level magnetic pulse compression unit was successfully constructed. The generator adopts magnetic pulse compression unit with metallic glass and ferrite cores, which compresses a 600 V, 10 μs primary pulse into short pulse with forward pumping current of 825 A, 60 ns and reverse pumping current of 1.3 kA, 30 ns. The current is sent to SOS in which the reverse pumping current is interrupted. The generator is capable of providing a pulse with the voltage of 120 kV and duration of 5-6 ns while output load being 125 Ω. The highest repetition rate is up to 1 kHz.
A 6 GW nanosecond solid-state generator based on semiconductor opening switch
NASA Astrophysics Data System (ADS)
Gusev, A. I.; Pedos, M. S.; Rukin, S. N.; Timoshenkov, S. P.; Tsyranov, S. N.
2015-11-01
In this paper, a nanosecond all solid-state generator providing peak power of up to 6 GW, output voltage of 500-900 kV, pulse length (full width at half maximum) of ˜7 ns across external loads of 40-100 Ω, and pulse repetition frequency up to 1 kHz in burst operation mode is described. The output pulse is generated by a semiconductor opening switch (SOS). A new SOS pumping circuit based on a double forming line (DFL) is proposed and its implementation described. As compared with a lumped capacitors-based pumping circuit, the DFL allows minimization of the inductance and stray capacitance of the reverse pumping circuit, and thus, an increase in the SOS cutoff current amplitude and generator output peak power as a whole. The pumping circuit provides a reverse current increasing through the SOS up to 14 kA within ˜12 ns. The SOS cuts off the current in ˜2 ns; the current cutoff rate reaches 7 kA/ns. The SOS braking power (the product of peak voltage and cutoff current) for an external load above 100 Ω is 13 GW.
All-solid-state repetitive semiconductor opening switch-based short pulse generator.
Ding, Zhenjie; Hao, Qingsong; Hu, Long; Su, Jiancang; Liu, Guozhi
2009-09-01
The operating characteristics of a semiconductor opening switch (SOS) are determined by its pumping circuit parameters. SOS is still able to cut off the current when pumping current duration falls to the order of tens of nanoseconds and a short pulse forms simultaneously in the output load. An all-solid-state repetitive SOS-based short pulse generator (SPG100) with a three-level magnetic pulse compression unit was successfully constructed. The generator adopts magnetic pulse compression unit with metallic glass and ferrite cores, which compresses a 600 V, 10 mus primary pulse into short pulse with forward pumping current of 825 A, 60 ns and reverse pumping current of 1.3 kA, 30 ns. The current is sent to SOS in which the reverse pumping current is interrupted. The generator is capable of providing a pulse with the voltage of 120 kV and duration of 5-6 ns while output load being 125 Omega. The highest repetition rate is up to 1 kHz. PMID:19791935
The dynamic of FUS-induced BBB Opening in Mouse Brain assessed by contrast enhanced MRI
NASA Astrophysics Data System (ADS)
Jenne, Jürgen W.; Krafft, Axel J.; Maier, Florian; Krause, Marie N.; Kleber, Susanne; Huber, Peter E.; Martin-Villalba, Ana; Bock, Michael
2010-03-01
Focused ultrasound (FUS) in combination with the administration of gas-filled microbubbles, can induce a localized and reversible opening of the blood brain barrier (BBB). Contrast enhanced magnetic resonance imaging (MRI) has been demonstrated as a precise tool to monitor such a local BBB disruption. However, the opening/closing mechanisms of the BBB with FUS are still largely unknown. In this ongoing project, we study the BBB opening dynamics in mouse brain comparing an interstitial and an intravascular MR contrast agent (CA). FUS in mouse brain was performed with an MRI compatible treatment setup (1.7 MHz fix-focus US transducer, f' = 68 mm, NA = 0.44; focus: 8.1 mm length; O/ = 1.1 mm) in a 1.5 T whole body MRI system. For BBB opening, forty 10 ms-long FUS-pulses were applied at a repetition rate of 1 Hz at 1 MPa. The i.v. administration of the micro bubbles (50 μl SonoVue®) was started simultaneously with FUS exposure. To analyze the BBB opening process, short-term and long-term MRI signal dynamics of the interstitial MR contrast agent Magnevist® and the intravascular CA Vasovist® (Bayer-Schering) were studied. To assess short-term signal dynamics, T1-weighted inversion recovery turbo FLASH images (1s) were repeatedly acquired. Repeated 3D FLASH acquisitions (90 s) were used to assess long-term MRI signal dynamics. The short-term MRI signal enhancements showed comparable time constants for both types of MR contrast agents: 1.1 s (interstitial) vs. 0.8 s (intravascular). This time constant may serve as a time constant of the BBB opening process with the given FUS exposure parameters. For the long-term signal dynamics the intravascular CA (62±10 min) showed a fife times greater time constant as the interstitial contrast agent (12±10 min). This might be explained by the high molecular weight (˜60 kDa) of the intravascular Vasovist due to its reversible binding to blood serum albumin resulting in a prolonged half-life in the blood stream compared to the
Non-adiabatic molecular dynamic simulations of opening reaction of molecular junctions
NASA Astrophysics Data System (ADS)
Zobač, Vladmír; Lewis, James P.; Jelínek, Pavel
2016-07-01
We report non-adiabatic molecular dynamic simulations of the ring opening reaction of diarylethene (DAE) derivative molecules, both free standing and embedded between gold electrodes. Simulations are performed by the surface hopping method employing density functional theory. Typically, the free-standing molecules exhibit large quantum yields to open and close; however the process is quenched for the molecules embedded between electrodes. Our simulations reveal the importance of the DAE side chemical groups, which explain the efficiency of the quenching process. Namely, delocalization of the LUMO state contributes to electronic coupling between the molecule and electrodes, suppressing or enhancing the reaction process. The simulations indicate that a proper choice of the chemical side group, which provides the strong localization of the LUMO state, can substantially diminish the quenching mechanism. Additionally, we analyze a strong dependency of the quantum yield of the opening reaction coming from the mechanical strength of the molecules.
Non-adiabatic molecular dynamic simulations of opening reaction of molecular junctions.
Zobač, Vladmír; Lewis, James P; Jelínek, Pavel
2016-07-15
We report non-adiabatic molecular dynamic simulations of the ring opening reaction of diarylethene (DAE) derivative molecules, both free standing and embedded between gold electrodes. Simulations are performed by the surface hopping method employing density functional theory. Typically, the free-standing molecules exhibit large quantum yields to open and close; however the process is quenched for the molecules embedded between electrodes. Our simulations reveal the importance of the DAE side chemical groups, which explain the efficiency of the quenching process. Namely, delocalization of the LUMO state contributes to electronic coupling between the molecule and electrodes, suppressing or enhancing the reaction process. The simulations indicate that a proper choice of the chemical side group, which provides the strong localization of the LUMO state, can substantially diminish the quenching mechanism. Additionally, we analyze a strong dependency of the quantum yield of the opening reaction coming from the mechanical strength of the molecules. PMID:27255903
Quantum Information Biology: From Theory of Open Quantum Systems to Adaptive Dynamics
NASA Astrophysics Data System (ADS)
Asano, Masanari; Basieva, Irina; Khrennikov, Andrei; Ohya, Masanori; Tanaka, Yoshiharu; Yamato, Ichiro
This chapter reviews quantum(-like) information biology (QIB). Here biology is treated widely as even covering cognition and its derivatives: psychology and decision making, sociology, and behavioral economics and finances. QIB provides an integrative description of information processing by bio-systems at all scales of life: from proteins and cells to cognition, ecological and social systems. Mathematically QIB is based on the theory of adaptive quantum systems (which covers also open quantum systems). Ideologically QIB is based on the quantum-like (QL) paradigm: complex bio-systems process information in accordance with the laws of quantum information and probability. This paradigm is supported by plenty of statistical bio-data collected at all bio-scales. QIB re ects the two fundamental principles: a) adaptivity; and, b) openness (bio-systems are fundamentally open). In addition, quantum adaptive dynamics provides the most generally possible mathematical representation of these principles.
Formulas for predicting the dynamic performance of ROCOF relays for embedded generation applications
Vieira, J.C. M.; Freitas, Walmir; Huang, Zhenyu; Xu, Wilsun; Morelato, A.
2006-07-13
A set of formulas directly predict the performance of rate-of-change-of-frequency (ROCOF) relays used to detect islanding of embedded synchronous generators. The formulas are analytically derived from the dynamic model of the generator and relay. Dynamic simulation results obtained using a representative distribution system confirm the validity and accuracy. The formulas presented are a useful tool for protection engineers; they can be used, for example, to assess the effectiveness of anti-islanding schemes based on ROCOF relays, or to assist the selection of relay settings, significantly reducing the number of repeated dynamic simulations necessary to carry out such studies.
Influence of external magnetic field on dynamics of open quantum systems
Kalandarov, Sh. A.; Kanokov, Z.; Adamian, G. G.; Antonenko, N. V.
2007-03-15
The influence of an external magnetic field on the non-Markovian dynamics of an open two-dimensional quantum system is investigated. The fluctuations of collective coordinate and momentum and transport coefficients are studied for a charged harmonic oscillator linearly coupled to a neutral bosonic heat bath. It is shown that the dissipation of collective energy slows down with increasing strength of the external magnetic field. The role of magnetic field in the diffusion processes is illustrated by several examples.
Quantifying the behavior of price dynamics at opening time in stock market
NASA Astrophysics Data System (ADS)
Ochiai, Tomoshiro; Takada, Hideyuki; Nacher, Jose C.
2014-11-01
The availability of huge volume of financial data has offered the possibility for understanding the markets as a complex system characterized by several stylized facts. Here we first show that the time evolution of the Japan’s Nikkei stock average index (Nikkei 225) futures follows the resistance and breaking-acceleration effects when the complete time series data is analyzed. However, in stock markets there are periods where no regular trades occur between the close of the market on one day and the next day’s open. To examine these time gaps we decompose the time series data into opening time and intermediate time. Our analysis indicates that for the intermediate time, both the resistance and the breaking-acceleration effects are still observed. However, for the opening time there are almost no resistance and breaking-acceleration effects, and volatility is always constantly high. These findings highlight unique dynamic differences between stock markets and forex market and suggest that current risk management strategies may need to be revised to address the absence of these dynamic effects at the opening time.
Robinson, Gail A; Spooner, Donna; Harrison, William J
2015-10-01
Frontal dynamic aphasia is characterised by a profound reduction in spontaneous speech despite well-preserved naming, repetition and comprehension. Since Luria (1966, 1970) designated this term, two main forms of dynamic aphasia have been identified: one, a language-specific selection deficit at the level of word/sentence generation, associated with left inferior frontal lesions; and two, a domain-general impairment in generating multiple responses or connected speech, associated with more extensive bilateral frontal and/or frontostriatal damage. Both forms of dynamic aphasia have been interpreted as arising due to disturbances in early prelinguistic conceptual preparation mechanisms that are critical for language production. We investigate language-specific and domain-general accounts of dynamic aphasia and address two issues: one, whether deficits in multiple conceptual preparation mechanisms can co-occur; and two, the contribution of broader cognitive processes such as energization, the ability to initiate and sustain response generation over time, to language generation failure. Thus, we report patient WAL who presented with frontal dynamic aphasia in the context of progressive supranuclear palsy (PSP). WAL was given a series of experimental tests that showed that his dynamic aphasia was not underpinned by a language-specific deficit in selection or in microplanning. By contrast, WAL presented with a domain-general deficit in fluent sequencing of novel thoughts. The latter replicated the pattern documented in a previous PSP patient (Robinson, et al., 2006); however, unique to WAL, generating novel thoughts was impaired but there was no evidence of a sequencing deficit because perseveration was absent. Thus, WAL is the first unequivocal case to show a distinction between novel thought generation and subsequent fluent sequencing. Moreover, WAL's generation deficit encompassed verbal and non-verbal responses, showing a similar (but more profoundly reduced) pattern
Dynamical generation and detection of entanglement in neutral leviton pairs
NASA Astrophysics Data System (ADS)
Dasenbrook, David; Flindt, Christian
2015-10-01
The entanglement of coherently split electron-hole pairs in an electronic conductor is typically not considered accessible due to particle number conservation and fermionic superselection rules. We demonstrate here that current cross-correlation measurements at the outputs of an electronic Mach-Zehnder interferometer can nevertheless provide a robust witness of electron-hole entanglement. Specifically, we consider neutral excitations generated by modulating the transmission of an unbiased quantum point contact periodically in time. For an optimized modulation profile, an entangled state with one positively-charged leviton (a hole) and one negatively-charged leviton (an electron) gets delocalized over the two paths of the interferometer and is detected at the output arms. We evaluate the influence of finite electronic temperatures and dephasing corresponding to recent experiments.
Reconfigurable optical interconnections via dynamic computer-generated holograms
NASA Technical Reports Server (NTRS)
Liu, Hua-Kuang (Inventor); Zhou, Shaomin (Inventor)
1994-01-01
A system is proposed for optically providing one-to-many irregular interconnections, and strength-adjustable many-to-many irregular interconnections which may be provided with strengths (weights) w(sub ij) using multiple laser beams which address multiple holograms and means for combining the beams modified by the holograms to form multiple interconnections, such as a cross-bar switching network. The optical means for interconnection is based on entering a series of complex computer-generated holograms on an electrically addressed spatial light modulator for real-time reconfigurations, thus providing flexibility for interconnection networks for largescale practical use. By employing multiple sources and holograms, the number of interconnection patterns achieved is increased greatly.
Reconfigurable Optical Interconnections Via Dynamic Computer-Generated Holograms
NASA Technical Reports Server (NTRS)
Liu, Hua-Kuang (Inventor); Zhou, Shao-Min (Inventor)
1996-01-01
A system is presented for optically providing one-to-many irregular interconnections, and strength-adjustable many-to-many irregular interconnections which may be provided with strengths (weights) w(sub ij) using multiple laser beams which address multiple holograms and means for combining the beams modified by the holograms to form multiple interconnections, such as a cross-bar switching network. The optical means for interconnection is based on entering a series of complex computer-generated holograms on an electrically addressed spatial light modulator for real-time reconfigurations, thus providing flexibility for interconnection networks for large-scale practical use. By employing multiple sources and holograms, the number of interconnection patterns achieved is increased greatly.
Nikovia, Christiana; Maroudas, Andreas-Philippos; Goulis, Panagiotis; Tzimis, Dionysios; Paraskevopoulou, Patrina; Pitsikalis, Marinos
2015-01-01
Statistical copolymers of norbornene (NBE) with cyclopentene (CP) were prepared by ring-opening metathesis polymerization, employing the 1st-generation Grubbs' catalyst, in the presence or absence of triphenylphosphine, PPh₃. The reactivity ratios were estimated using the Finemann-Ross, inverted Finemann-Ross, and Kelen-Tüdos graphical methods, along with the computer program COPOINT, which evaluates the parameters of binary copolymerizations from comonomer/copolymer composition data by integrating a given copolymerization equation in its differential form. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the mean sequence length, which were derived using the monomer reactivity ratios. The kinetics of thermal decomposition of the copolymers along with the respective homopolymers was studied by thermogravimetric analysis within the framework of the Ozawa-Flynn-Wall and Kissinger methodologies. Finally, the effect of triphenylphosphine on the kinetics of copolymerization, the reactivity ratios, and the kinetics of thermal decomposition were examined. PMID:26343620
Influence of open water bodies on the generation of summertime convection over the Canadian Prairies
NASA Astrophysics Data System (ADS)
Joshi, D.; Bélair, S.; Carrera, M. L.; Leroyer, S.
2014-12-01
There are still numerous water features on the Canadian landscape that are not monitored. Specifically, there are landscape features (e.g. the prairies and Canadian shield regions of North America) that are ephemeral in nature and have a significant influence on convective storm generation and local weather patterns through turbulent exchanges of sensible and latent heat between land and the atmosphere. In this study we perform a series of numerical experiments with the GEM (Global Environmental Multiscale model) model at 2.5 km resolution to examine the sensitivity of the atmospheric boundary layer to the presence of open water bodies. At present the land-water fraction in the GEM model is specified by means of static geophysical databases which do not change annually. Uncertainty is introduced into this land-water fraction and the sensitivity of the resulting soil moisture and precipitation is quantified for a series of convective precipitation events over Alberta for the summer 2014 period.
Is {open_quotes}early commitment{close_quotes} in plan generation ever a good idea?
Joslin, D.; Pollack, M.E.
1996-12-31
Partial-Order Causal Link planners typically take a {open_quotes}least-commitment{close_quotes} approach to some decisions (notably, step ordering), postponing those decisions until constraints force them to be made. However, these planners rely to some degree on early commitments in making other types of decisions, including threat resolution and operator choice. We show why existing planners cannot support full least-commitment decision-making, and present an alternative approach that can. The approach has been implemented in the Descartes system, which we describe. We also provide experimental results that demonstrate that a least-commitment approach to planning can be profitably extended beyond what is done in POCL and similar planners, but that taking a least-commitment approach to every planning decision can be inefficient: early commitment in plan generation is sometimes a good idea.
NeuroPG: open source software for optical pattern generation and data acquisition
Avants, Benjamin W.; Murphy, Daniel B.; Dapello, Joel A.; Robinson, Jacob T.
2015-01-01
Patterned illumination using a digital micromirror device (DMD) is a powerful tool for optogenetics. Compared to a scanning laser, DMDs are inexpensive and can easily create complex illumination patterns. Combining these complex spatiotemporal illumination patterns with optogenetics allows DMD-equipped microscopes to probe neural circuits by selectively manipulating the activity of many individual cells or many subcellular regions at the same time. To use DMDs to study neural activity, scientists must develop specialized software to coordinate optical stimulation patterns with the acquisition of electrophysiological and fluorescence data. To meet this growing need we have developed an open source optical pattern generation software for neuroscience—NeuroPG—that combines, DMD control, sample visualization, and data acquisition in one application. Built on a MATLAB platform, NeuroPG can also process, analyze, and visualize data. The software is designed specifically for the Mightex Polygon400; however, as an open source package, NeuroPG can be modified to incorporate any data acquisition, imaging, or illumination equipment that is compatible with MATLAB’s Data Acquisition and Image Acquisition toolboxes. PMID:25784873
Xing, Xiaobo; Zheng, Jiapeng; Li, Fengjia; Sun, Chao; Cai, Xiang; Zhu, Debin; Lei, Liang; Wu, Ting; Zhou, Bin; Evans, Julian; Chen, Ziyi
2014-01-01
Thermal microbubbles generally grow directly from the heater and are spherical to minimize surface tension. We demonstrate a novel type of microbubble indirectly generated from a graphene oxide-microheater. Graphene oxide's photothermal properties allowed for efficient generation of a thermal gradient field on the microscale. A series of approximately ellipsoidal microbubbles were generated on the smooth microwire based on heterogeneous nucleation. Other dynamic behaviors induced by the microheater such as constant growth, directional transport and coalescence were also investigated experimentally and theoretically. The results are not only helpful for understanding the bubble dynamics but also useful for developing novel photothermal bubble-based devices. PMID:25124694
Response of borehole extensometers to explosively generated dynamic loads
Patrick, W.C.; Brough, W.G.
1980-08-25
Commercially available, hydraulically anchored, multiple-point borehole extensometers (MPBX) were evaluated with respect to response to dynamic loads produced by explosions. This study is part of the DOE-funded Spent Fuel Test-Climax (SFT-C), currently being conducted in the Climax granitic stock at the Nevada Test Site. The SFT-C is an investigation of the feasibility of short-term storage and retrieval of spent nuclear reactor fuel assemblies at a plausible repository depth in granitic rock. Eleven spent fuel assemblies are stored at a depth of 420 m for three to five years, and will then be retrieved. MPBX units are used in the SFT-C to measure both excavation-induced and thermally induced rock displacements. Long-term reliability of extensometers in this hostile environment is essential in order to obtain valid data during the course of this test. Research to date shows conclusively that extensometers of this type continue to function reliably even though subjected to accelerations of 1.8 g; research also implies that they function well though subjected to accelerations in excess of 100 g. MPBX survivability during the first four months of testing at ambient temperatures was about 90 percent.
Dynamical mass generation in strongly coupled quantum electrodynamics with weak magnetic fields
Ayala, Alejandro; Raya, Alfredo; Rojas, Eduardo; Bashir, Adnan
2006-05-15
We study the dynamical generation of masses for fundamental fermions in quenched quantum electrodynamics in the presence of weak magnetic fields using Schwinger-Dyson equations. Contrary to the case where the magnetic field is strong, in the weak field limit the coupling should exceed certain critical value in order for the generation of masses to take place, just as in the case where no magnetic field is present. The weak field limit is defined as eB<
ERIC Educational Resources Information Center
Field, John
2013-01-01
This exploratory paper considers the concept of generation in the context of learning across the life course. Although researchers have often found considerable inequalities in participation by age, as well as strongly articulated attitudinal differences, there have so far been only a handful of studies that have explored these patterns through…
Dynamic Gate Product and Artifact Generation from System Models
NASA Technical Reports Server (NTRS)
Jackson, Maddalena; Delp, Christopher; Bindschadler, Duane; Sarrel, Marc; Wollaeger, Ryan; Lam, Doris
2011-01-01
Model Based Systems Engineering (MBSE) is gaining acceptance as a way to formalize systems engineering practice through the use of models. The traditional method of producing and managing a plethora of disjointed documents and presentations ("Power-Point Engineering") has proven both costly and limiting as a means to manage the complex and sophisticated specifications of modern space systems. We have developed a tool and method to produce sophisticated artifacts as views and by-products of integrated models, allowing us to minimize the practice of "Power-Point Engineering" from model-based projects and demonstrate the ability of MBSE to work within and supersede traditional engineering practices. This paper describes how we have created and successfully used model-based document generation techniques to extract paper artifacts from complex SysML and UML models in support of successful project reviews. Use of formal SysML and UML models for architecture and system design enables production of review documents, textual artifacts, and analyses that are consistent with one-another and require virtually no labor-intensive maintenance across small-scale design changes and multiple authors. This effort thus enables approaches that focus more on rigorous engineering work and less on "PowerPoint engineering" and production of paper-based documents or their "office-productivity" file equivalents.
NASA Astrophysics Data System (ADS)
Shankar, Chandrashekar
The goal of this research was to gain a fundamental understanding of the properties of networks created by the ring opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD) used in self-healing materials. To this end we used molecular simulation methods to generate realistic structures of DCPD networks, characterize their structures, and determine their mechanical properties. Density functional theory (DFT) calculations, complemented by structural information derived from molecular dynamics simulations were used to reconstruct experimental Raman spectra and differential scanning calorimetry (DSC) data. We performed coarse-grained simulations comparing networks generated via the ROMP reaction process and compared them to those generated via a RANDOM process, which led to the fundamental realization that the polymer topology has a unique influence on the network properties. We carried out fully atomistic simulations of DCPD using a novel algorithm for recreating ROMP reactions of DCPD molecules. Mechanical properties derived from these atomistic networks are in excellent agreement with those obtained from coarse-grained simulations in which interactions between nodes are subject to angular constraints. This comparison provides self-consistent validation of our simulation results and helps to identify the level of detail necessary for the coarse-grained interaction model. Simulations suggest networks can classified into three stages: fluid-like, rubber-like or glass-like delineated by two thresholds in degree of reaction alpha: The onset of finite magnitudes for the Young's modulus, alphaY, and the departure of the Poisson ration from 0.5, alphaP. In each stage the polymer exhibits a different predominant mechanical response to deformation. At low alpha < alphaY it flows. At alpha Y < alpha < alphaP the response is entropic with no change in internal energy. At alpha > alphaP the response is enthalpic change in internal energy. We developed graph theory
STARS 2.0: 2nd-generation open-source archiving and query software
NASA Astrophysics Data System (ADS)
Winegar, Tom
2008-07-01
The Subaru Telescope is in process of developing an open-source alternative to the 1st-generation software and databases (STARS 1) used for archiving and query. For STARS 2, we have chosen PHP and Python for scripting and MySQL as the database software. We have collected feedback from staff and observers, and used this feedback to significantly improve the design and functionality of our future archiving and query software. Archiving - We identified two weaknesses in 1st-generation STARS archiving software: a complex and inflexible table structure and uncoordinated system administration for our business model: taking pictures from the summit and archiving them in both Hawaii and Japan. We adopted a simplified and normalized table structure with passive keyword collection, and we are designing an archive-to-archive file transfer system that automatically reports real-time status and error conditions and permits error recovery. Query - We identified several weaknesses in 1st-generation STARS query software: inflexible query tools, poor sharing of calibration data, and no automatic file transfer mechanisms to observers. We are developing improved query tools and sharing of calibration data, and multi-protocol unassisted file transfer mechanisms for observers. In the process, we have redefined a 'query': from an invisible search result that can only transfer once in-house right now, with little status and error reporting and no error recovery - to a stored search result that can be monitored, transferred to different locations with multiple protocols, reporting status and error conditions and permitting recovery from errors.
NASA Astrophysics Data System (ADS)
Jin, Shengye; Tamura, Masayuki
2013-10-01
Monte Carlo Ray Tracing (MCRT) method is a versatile application for simulating radiative transfer regime of the Solar - Atmosphere - Landscape system. Moreover, it can be used to compute the radiation distribution over a complex landscape configuration, as an example like a forest area. Due to its robustness to the complexity of the 3-D scene altering, MCRT method is also employed for simulating canopy radiative transfer regime as the validation source of other radiative transfer models. In MCRT modeling within vegetation, one basic step is the canopy scene set up. 3-D scanning application was used for representing canopy structure as accurately as possible, but it is time consuming. Botanical growth function can be used to model the single tree growth, but cannot be used to express the impaction among trees. L-System is also a functional controlled tree growth simulation model, but it costs large computing memory. Additionally, it only models the current tree patterns rather than tree growth during we simulate the radiative transfer regime. Therefore, it is much more constructive to use regular solid pattern like ellipsoidal, cone, cylinder etc. to indicate single canopy. Considering the allelopathy phenomenon in some open forest optical images, each tree in its own `domain' repels other trees. According to this assumption a stochastic circle packing algorithm is developed to generate the 3-D canopy scene in this study. The canopy coverage (%) and the tree amount (N) of the 3-D scene are declared at first, similar to the random open forest image. Accordingly, we randomly generate each canopy radius (rc). Then we set the circle central coordinate on XY-plane as well as to keep circles separate from each other by the circle packing algorithm. To model the individual tree, we employ the Ishikawa's tree growth regressive model to set the tree parameters including DBH (dt), tree height (H). However, the relationship between canopy height (Hc) and trunk height (Ht) is
Dynamic visual cues induce jaw opening and closing by tiger beetles during pursuit of prey
Zurek, Daniel B.; Perkins, Madeleine Q.; Gilbert, Cole
2014-01-01
In dynamic locomotory contexts, visual cues often trigger adaptive behaviour by the viewer, yet studies investigating how animals determine impending collisions typically employ either stationary viewers or objects. Here, we describe a dynamic situation of visually guided prey pursuit in which both impending prey contact and escape elicit observable adaptive behaviours in the pursuer, a predatory beetle. We investigated which visual cues may independently control opening and closing of the beetle's jaws during chases of prey dummies. Jaw opening and closing typically occur when prey is within the 60° binocular field, but not at specific distances, angular sizes or time-to-collision. We show that a sign change in the expansion rate of the target image precedes jaw opening (16 ms) and closing (35 ms), signalling to the beetle that it is gaining on the target or that the target is getting away. We discuss the ‘sloppiness' of such variation in the lag of the behavioural response, especially jaw closing, as an adaptation to uncertainty about target position due to degradation of the target image by motion blur from the fast-running beetle. PMID:25376803
Khambhati, Ankit N; Davis, Kathryn A; Oommen, Brian S; Chen, Stephanie H; Lucas, Timothy H; Litt, Brian; Bassett, Danielle S
2015-12-01
The epileptic network is characterized by pathologic, seizure-generating 'foci' embedded in a web of structural and functional connections. Clinically, seizure foci are considered optimal targets for surgery. However, poor surgical outcome suggests a complex relationship between foci and the surrounding network that drives seizure dynamics. We developed a novel technique to objectively track seizure states from dynamic functional networks constructed from intracranial recordings. Each dynamical state captures unique patterns of network connections that indicate synchronized and desynchronized hubs of neural populations. Our approach suggests that seizures are generated when synchronous relationships near foci work in tandem with rapidly changing desynchronous relationships from the surrounding epileptic network. As seizures progress, topographical and geometrical changes in network connectivity strengthen and tighten synchronous connectivity near foci-a mechanism that may aid seizure termination. Collectively, our observations implicate distributed cortical structures in seizure generation, propagation and termination, and may have practical significance in determining which circuits to modulate with implantable devices. PMID:26680762
On trajectory generation for flexible space crane: Inverse dynamics analysis by LATDYN
NASA Technical Reports Server (NTRS)
Chen, G.-S.; Housner, J. M.; Wu, S.-C.; Chang, C.-W.
1989-01-01
For future in-space construction facility, one or more space cranes capable of manipulating and positioning large and massive spacecraft components will be needed. Inverse dynamics was extensively studied as a basis for trajectory generation and control of robot manipulators. The focus here is on trajectory generation in the gross-motion phase of space crane operation. Inverse dynamics of the flexible crane body is much more complex and intricate as compared with rigid robot link. To model and solve the space crane's inverse dynamics problem, LATDYN program which employs a three-dimensional finite element formulation for the multibody truss-type structures will be used. The formulation is oriented toward a joint dominated structure which is suitable for the proposed space crane concept. To track a planned trajectory, procedures will be developed to obtain the actuation profile and dynamics envelope which are pertinent to the design and performance requirements of the space crane concept.
Probing the holographic principle using dynamical gauge effects from open spin-orbit coupling
NASA Astrophysics Data System (ADS)
Zhao, Jianshi; Price, Craig; Liu, Qi; Gemelke, Nathan
2016-05-01
Dynamical gauge fields result from locally defined symmetries and an effective over-labeling of quantum states. Coupling atoms weakly to a reservoir of laser modes can create an effective dynamical gauge field purely due to the disregard of information in the optical states. Here we report measurements revealing effects of open spin-orbit coupling in a system where an effective model can be formed from a non-abelian SU(2) × U(1) field theory following the Yang-Mills construct. Forming a close analogy to dynamical gauge effects in quantum chromodynamics, we extract a measure of atomic motion which reveals the analog of a closing mass gap for the relevant gauge boson, shedding insight on long standing open problems in gauge-fixing scale anomalies. Using arguments following the holographic principle, we measure scaling relations which can be understood by quantifying information present in the local potential. New prospects using these techniques for developing fractionalization of multi-particle and macroscopic systems using dissipative and non-abelian gauge fields will also be discussed. We acknowledge support from NSF Award No. 1068570, and the Charles E. Kaufman Foundation.
Studying dynamic chaos in microwave ring generators based on normally magnetized ferromagnetic film
NASA Astrophysics Data System (ADS)
Kondrashov, A. V.; Ustinov, A. B.; Kalinikos, B. A.
2016-02-01
We present results of an experimental investigation of the transition to a microwave dynamic chaos regime in ring oscillators based on normally magnetized yttrium iron garnet (YIG) films. It is established that an increase in the ring gain leads to the sequential generation of monochromatic, periodic, quasi-periodic, and chaotic signals. The quasi-periodic regime is characterized by the appearance of secondary modulation of the signal amplitude. In the regime of dynamic chaos generation, the parameters can be controlled by gain of the ring.
Reconstruction of correlation-driven electron-hole dynamics by high-harmonic-generation spectroscopy
NASA Astrophysics Data System (ADS)
Leeuwenburgh, Jonathan; Cooper, Bridgette; Averbukh, Vitali; Marangos, Jonathan P.; Ivanov, Misha
2014-09-01
We present detailed analysis of the recently proposed technique of high-order-harmonic generation spectroscopy of correlation-driven electron hole dynamics in atoms and molecules. This novel technique resolves Auger-type processes with attosecond-scale resolution by clocking the decay process with high-harmonic generation. The harmonic generation is driven by an attosecond, XUV pump pulse and a long-duration, infrared pulse. We present the strong-field-approximation-based theory of such an XUV-initiated high-order-harmonic generation process. We detail different ways of recovering the hole survival probability by altering experimental parameters to change the time-energy mapping of the harmonics. The various reconstruction methods are then simulated for M4,5NN Auger decay in krypton and molecular-orbital breakdown dynamics in trans-butadiene and propanal.
A nonlinear dynamic model of a once-through, helical-coil steam generator
Abdalla, M.A.
1993-07-01
A dynamic model of a once-through, helical-coil steam generator is presented. The model simulates the advanced liquid metal reactor superheated cycle steam generator with a four-region, moving-boundary, drift-flux model. The model is described by a set of nonlinear differential equations derived from the fundamental equations of conversation of mass, energy, and momentum. Sample results of steady-state and transient calculations are presented.
Min'zhenkova, M E; Shilova, N V; Markova, Zh G; Antonenko, V G; Lebedev, I N; Kozlova, Iu O; Zemliakova, V V; Zolotukhina, T V
2013-10-01
The present work was aimed at generating the dynamic standard reference intervals (DSRI) and their application for chromosomal-aberration (CA) analysis. The evaluation of the generated DSRI was performed using the DNA samples from four patients with already known CA. High-resolution comparative genomic hybridization analysis (HR-CGH) allowed us to not only identify all of the CAs, that were not revealed by CGH, but also to detect the breakpoints and to determine the size of chromosomal imbalance. PMID:25474900
Demonstration of open-quantum-system optimal control in dynamic nuclear polarization
NASA Astrophysics Data System (ADS)
Sheldon, S.; Cory, D. G.
2015-10-01
Dynamic nuclear polarization (DNP) is used in nuclear magnetic resonance to transfer polarization from electron spins to nuclear spins. The resulting nuclear polarization enhancement can, in theory, be two or three orders of magnitude depending on the sample. In solid-state systems, however, there are competing mechanisms of DNP, which, when occurring simultaneously, reduce the net polarization enhancement of the nuclear spin. We present a simple quantum description of DNP and apply optimal control theory (OCT) with an open-quantum-system framework to design pulses that select one DNP process and suppress the others. We demonstrate experimentally an order of magnitude improvement in the DNP enhancement using OCT pulses.
ERIC Educational Resources Information Center
Sadeh, Irit; Zion, Michal
2009-01-01
Dynamic inquiry learning emphasizes aspects of change, intellectual flexibility, and critical thinking. Dynamic inquiry learning is characterized by the following criteria: learning as a process, changes during the inquiry, procedural understanding, and affective points of view. This study compared the influence of open versus guided inquiry…
NASA Astrophysics Data System (ADS)
Qian, Hong
2014-10-01
The study of biological cells in terms of mesoscopic, nonequilibrium, nonlinear, stochastic dynamics of open chemical systems provides a paradigm for other complex, self-organizing systems with ultra-fast stochastic fluctuations, short-time deterministic nonlinear dynamics, and long-time evolutionary behavior with exponentially distributed rare events, discrete jumps among punctuated equilibria, and catastrophe.
Automated Flight Dynamics Product Generation for the EOS AM-1 Spacecraft
NASA Technical Reports Server (NTRS)
Matusow, Carla
1999-01-01
As part of NASA's Earth Science Enterprise, the Earth Observing System (EOS) AM-1 spacecraft is designed to monitor long-term, global, environmental changes. Because of the complexity of the AM-1 spacecraft, the mission operations center requires more than 80 distinct flight dynamics products (reports). To create these products, the AM-1 Flight Dynamics Team (FDT) will use a combination of modified commercial software packages (e.g., Analytical Graphic's Satellite ToolKit) and NASA-developed software applications. While providing the most cost-effective solution to meeting the mission requirements, the integration of these software applications raises several operational concerns: (1) Routine product generation requires knowledge of multiple applications executing on variety of hardware platforms. (2) Generating products is a highly interactive process requiring a user to interact with each application multiple times to generate each product. (3) Routine product generation requires several hours to complete. (4) User interaction with each application introduces the potential for errors, since users are required to manually enter filenames and input parameters as well as run applications in the correct sequence. Generating products requires some level of flight dynamics expertise to determine the appropriate inputs and sequencing. To address these issues, the FDT developed an automation software tool called AutoProducts, which runs on a single hardware platform and provides all necessary coordination and communication among the various flight dynamics software applications. AutoProducts, autonomously retrieves necessary files, sequences and executes applications with correct input parameters, and deliver the final flight dynamics products to the appropriate customers. Although AutoProducts will normally generate pre-programmed sets of routine products, its graphical interface allows for easy configuration of customized and one-of-a-kind products. Additionally, Auto
Obata, Toshio; Nakashima, Michiko
2016-07-15
The present study examined whether opening of adenosine triphosphate (ATP) sensitive K(+) (KATP) channels can enhance 1-methyl-4-phenylpyridinium (MPP(+))-induced hydroxyl radical (OH) generation in rat striatum. Rats were anesthetized, and sodium salicylate in Ringer's solution (0.5nmol/ml per min) was infused through a microdialysis probe to detect the generation of OH as reflected by the non-enzymatic formation of 2.3-dihydroxybenzoic acid (DHBA) in the striatum. MPP(+) (5mM) enhanced generation of OH with concomitant increased efflux of dopamine (DA). Cromakalim (100μM), a KATP channel opener, through the microdialysis probe significantly increased both DA efflux and OH formation induced by MPP(+). Another KATP channel opener, nicorandil (1mM), also increased the level DA or DHBA, but these changes were not significant. However, in the presence of glibenclamide (10μM), a KATP channel antagonist, and the increase of MPP(+)-induced DA or DHBA were not observed. Cromakalim (10, 50 and 100μM) increased MPP(+)-induced DHBA formation in a concentration-dependent manner. However, the effects of cromakalim in the presence of glibenclamide were abolished. These results suggest that opening of KATP channels may cause OH generation by MPP(+). PMID:27288802