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Sample records for activity confinement system

  1. Confinement of active systems: trapping, swim pressure, and explosions

    NASA Astrophysics Data System (ADS)

    Takatori, Sho; de Dier, Raf; Vermant, Jan; Brady, John

    2015-11-01

    We analyze the run-and-tumble dynamics and motion of living bacteria and self-propelled Janus motors confined in an acoustic trap. Since standard optical tweezers are far too weak, we developed an acoustic trap strong enough to confine swimmers over distances large compared to the swimmers' size and run length. The external trap behaves as an ``osmotic barrier'' that confines the swimmers inside the trapping region, analogous to semipermeable membranes that confine passive Brownian particles inside a boundary. From the swimmers' restricted motion inside the trap, we calculate the unique swim pressure generated by active systems originating from the force required to confine them by boundaries. We apply a strong trap to collect the swimmers into a close-packed active crystal and then turn off the trap which causes the crystal to ``explode'' due to an imbalance of the active pressure. We corroborate all experimental results with Brownian dynamics simulations and analytical theory. ST is supported by a Gates Millennium Scholars fellowship and a NSF Fellowship No. DGE-1144469. RDD is supported by a doctoral fellowship of the fund for scientific research (FWO-Vlaanderen). This work is also supported by NSF Grant CBET 1437570.

  2. Characterization of the airborne activity confinement system prefilter material

    SciTech Connect

    Long, T.A.; Monson, P.R.

    1992-05-01

    A general concern with assessing the effects of postulated severe accidents is predicting and preventing the release of radioactive isotopes to the environment at the Savannah River Site (SRS) reactor. Unless the confinement systems are breached in an accident the Airborne Activity Confinement System forces all of the internal air through the filter compartments. Proper modeling of the radioactivity released to the environment requires knowledge of the filtering characteristics of the demisters, the HEPA`s, and the charcoal beds. An investigation of the mass loading characteristics for a range of particle sizes was performed under the direction of Vince Novick of Argonne National Laboratory (ANL) for the Savannah River Technology Center (SRTC) in connection with the restart of the K reactor. Both solid and liquid aerosols were used to challenge sample prefilter and HEPA filters. The results of the ANL investigation are reported in this document.

  3. Characterization of the airborne activity confinement system prefilter material

    SciTech Connect

    Long, T.A.; Monson, P.R.

    1992-05-01

    A general concern with assessing the effects of postulated severe accidents is predicting and preventing the release of radioactive isotopes to the environment at the Savannah River Site (SRS) reactor. Unless the confinement systems are breached in an accident the Airborne Activity Confinement System forces all of the internal air through the filter compartments. Proper modeling of the radioactivity released to the environment requires knowledge of the filtering characteristics of the demisters, the HEPA's, and the charcoal beds. An investigation of the mass loading characteristics for a range of particle sizes was performed under the direction of Vince Novick of Argonne National Laboratory (ANL) for the Savannah River Technology Center (SRTC) in connection with the restart of the K reactor. Both solid and liquid aerosols were used to challenge sample prefilter and HEPA filters. The results of the ANL investigation are reported in this document.

  4. Alternate particle removal technologies for the Airborne Activity Confinement System at the Savannah River Site

    SciTech Connect

    Brockmann, J.E.; Adkins, C.L.J.; Gelbard, F. )

    1991-09-01

    This report presents a review of the filtration technologies available for the removal of particulate material from a gas stream. It was undertaken to identify alternate filtration technologies that may be employed in the Airborne Activity Confinement System (AACS) at the Savannah River Plant. This report is organized into six sections: (1) a discussion of the aerosol source term and its definition, (2) a short discussion of particle and gaseous contaminant removal mechanisms, (3) a brief overview of particle removal technologies, (4) a discussion of the existing AACS and its potential shortcomings, (5) an enumeration of issues to be addressed in upgrading the AACS, and, (6) a detailed discussion of the identified technologies. The purpose of this report is to identity available options to the existing particle removal system. This system is in continuous operation during routine operation of the reactor. As will be seen, there are a number of options and the selection of any technology or combination of technologies will depend on the design aerosol source term (yet to be appropriately defined) as well as the flow requirements and configuration. This report does not select a specific technology. It focuses on particulate removal and qualitatively on the removal of radio-iodine and mist elimination. Candidate technologies have been selected from industrial and nuclear gas cleaning applications.

  5. Active cooling-based surface confinement system for thermal soil treatment

    DOEpatents

    Aines, Roger D.; Newmark, Robin L.

    1997-01-01

    A thermal barrier is disclosed for surface confinement with active cooling to control subsurface pressures during thermal remediation of shallow (5-20 feet) underground contaminants. If steam injection is used for underground heating, the actively cooled thermal barrier allows the steam to be injected into soil at pressures much higher (20-60 psi) than the confining strength of the soil, while preventing steam breakthrough. The rising steam is condensed to liquid water at the thermal barrier-ground surface interface. The rapid temperature drop forced by the thermal barrier drops the subsurface pressure to below atmospheric pressure. The steam and contaminant vapors are contained by the thermal blanket, which can be made of a variety of materials such as steel plates, concrete slabs, membranes, fabric bags, or rubber bladders.

  6. Active cooling-based surface confinement system for thermal soil treatment

    DOEpatents

    Aines, R.D.; Newmark, R.L.

    1997-10-28

    A thermal barrier is disclosed for surface confinement with active cooling to control subsurface pressures during thermal remediation of shallow (5-20 feet) underground contaminants. If steam injection is used for underground heating, the actively cooled thermal barrier allows the steam to be injected into soil at pressures much higher (20-60 psi) than the confining strength of the soil, while preventing steam breakthrough. The rising steam is condensed to liquid water at the thermal barrier-ground surface interface. The rapid temperature drop forced by the thermal barrier drops the subsurface pressure to below atmospheric pressure. The steam and contaminant vapors are contained by the thermal blanket, which can be made of a variety of materials such as steel plates, concrete slabs, membranes, fabric bags, or rubber bladders. 1 fig.

  7. Spontaneous Circulation of Confined Active Suspensions

    NASA Astrophysics Data System (ADS)

    Woodhouse, Francis; Goldstein, Raymond

    2012-11-01

    Many active fluid systems encountered in biology are set in total geometric confinement; cytoplasmic streaming is a prominent and ubiquitous example. Using the simple paradigm of a dilute dipolar swimmer suspension, we demonstrate that the two key constraints of circular confinement and fluid incompressibility yield qualitatively new dynamics, effectively quantizing the behaviour regimes. We show analytically that there is an activity threshold for spontaneous auto-circulation and verify this numerically. Long-time non-linear behaviour is investigated via simulations, which reveal steady states displaying nematic defect separation and a high-activity bifurcation to an oscillatory regime.

  8. Active nematics confined within a shell

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Zhou, Ye; Rahimi, Mohammad; de Pablo, Juan; dePablo Team

    Active fluids exhibit many striking flow patterns when confined within complex geometries. For example, recent work has demonstrated that when a thin film of extensile microtubules is confined within a vesicle, the four + 1 / 2 defects periodically oscillate between a tetrahedral and a planar configuration (Keber, et al. Science (2014). Here we employ hybrid lattice Boltzmann simulations to study the dynamics of active nematics confined between two concentric spherical surfaces. We find that in both extensile and contractile systems, the four defects are coupled with noticeable macroscopic velocities and they move along their symmetry axes, eventhough in different patterns. We observe that in extensile systems with moderate activity, defects repel each other due to elastic forces, and their collective motion leads to the same patterned dynamics as observed in the above experiment. We further show that this periodic dynamics is accompanied by oscillations of the defect velocity, system's elastic energy, and the emergence and annihilation of vortices. We also observe that with stronger activity, the extensile system evolves to chaos. In contrast, the contractile system remains passive for the entire activity range, with defects being attracted to each other in pairs.

  9. Mirror Confinement Systems: project summaries

    SciTech Connect

    Not Available

    1980-07-01

    This report contains descriptions of the projects supported by the Mirror Confinement Systems (MCS) Division of the Office of Fusion Energy. The individual project summaries were prepared by the principal investigators, in collaboration with MCS staff office, and include objectives and milestones for each project. In addition to project summaries, statements of Division objectives and budget summaries are also provided.

  10. Spontaneous circulation of confined active suspensions.

    PubMed

    Woodhouse, Francis G; Goldstein, Raymond E

    2012-10-19

    Many active fluid systems encountered in biology are set in total geometric confinement. Cytoplasmic streaming in plant cells is a prominent and ubiquitous example, in which cargo-carrying molecular motors move along polymer filaments and generate coherent cell-scale flow. When filaments are not fixed to the cell periphery, a situation found both in vivo and in vitro, we observe that the basic dynamics of streaming are closely related to those of a nonmotile stresslet suspension. Under this model, it is demonstrated that confinement makes possible a stable circulating state; a linear stability analysis reveals an activity threshold for spontaneous autocirculation. Numerical analysis of the longtime behavior reveals a phenomenon akin to defect separation in nematic liquid crystals and a high-activity bifurcation to an oscillatory regime. PMID:23215137

  11. Spontaneous Circulation of Confined Active Suspensions

    NASA Astrophysics Data System (ADS)

    Woodhouse, Francis G.; Goldstein, Raymond E.

    2012-10-01

    Many active fluid systems encountered in biology are set in total geometric confinement. Cytoplasmic streaming in plant cells is a prominent and ubiquitous example, in which cargo-carrying molecular motors move along polymer filaments and generate coherent cell-scale flow. When filaments are not fixed to the cell periphery, a situation found both in vivo and in vitro, we observe that the basic dynamics of streaming are closely related to those of a nonmotile stresslet suspension. Under this model, it is demonstrated that confinement makes possible a stable circulating state; a linear stability analysis reveals an activity threshold for spontaneous autocirculation. Numerical analysis of the longtime behavior reveals a phenomenon akin to defect separation in nematic liquid crystals and a high-activity bifurcation to an oscillatory regime.

  12. Interfacial electrofluidics in confined systems

    PubMed Central

    Tang, Biao; Groenewold, Jan; Zhou, Min; Hayes, Robert A.; Zhou, Guofu (G.F.)

    2016-01-01

    Electrofluidics is a versatile principle that can be used for high speed actuation of liquid interfaces. In most of the applications, the fundamental mechanism of electro-capillary instability plays a crucial role, yet it’s potential richness in confined fluidic layers has not been well addressed. Electrofluidic displays which are comprised of thin pixelated colored films in a range of architectures are excellent systems for studying such phenomena. In this study we show theoretically and experimentally that confinement leads to the generation of a cascade of voltage dependent modes as a result of the electro-capillary instability. In the course of reconciling theory with our experimental data we have observed a number of previously unreported phenomena such as a significant induction time (several milliseconds) prior to film rupture as well as a rupture location not corresponding to the minimum electric field strength in the case of the standard convex water/oil interface used in working devices. These findings are broadly applicable to a wide range of switchable electrofluidic applications and devices having confined liquid films. PMID:27221211

  13. Interfacial electrofluidics in confined systems

    NASA Astrophysics Data System (ADS)

    Tang, Biao; Groenewold, Jan; Zhou, Min; Hayes, Robert A.; Zhou, Guofu (G. F.)

    2016-05-01

    Electrofluidics is a versatile principle that can be used for high speed actuation of liquid interfaces. In most of the applications, the fundamental mechanism of electro-capillary instability plays a crucial role, yet it’s potential richness in confined fluidic layers has not been well addressed. Electrofluidic displays which are comprised of thin pixelated colored films in a range of architectures are excellent systems for studying such phenomena. In this study we show theoretically and experimentally that confinement leads to the generation of a cascade of voltage dependent modes as a result of the electro-capillary instability. In the course of reconciling theory with our experimental data we have observed a number of previously unreported phenomena such as a significant induction time (several milliseconds) prior to film rupture as well as a rupture location not corresponding to the minimum electric field strength in the case of the standard convex water/oil interface used in working devices. These findings are broadly applicable to a wide range of switchable electrofluidic applications and devices having confined liquid films.

  14. Interfacial electrofluidics in confined systems.

    PubMed

    Tang, Biao; Groenewold, Jan; Zhou, Min; Hayes, Robert A; Zhou, Guofu G F

    2016-01-01

    Electrofluidics is a versatile principle that can be used for high speed actuation of liquid interfaces. In most of the applications, the fundamental mechanism of electro-capillary instability plays a crucial role, yet it's potential richness in confined fluidic layers has not been well addressed. Electrofluidic displays which are comprised of thin pixelated colored films in a range of architectures are excellent systems for studying such phenomena. In this study we show theoretically and experimentally that confinement leads to the generation of a cascade of voltage dependent modes as a result of the electro-capillary instability. In the course of reconciling theory with our experimental data we have observed a number of previously unreported phenomena such as a significant induction time (several milliseconds) prior to film rupture as well as a rupture location not corresponding to the minimum electric field strength in the case of the standard convex water/oil interface used in working devices. These findings are broadly applicable to a wide range of switchable electrofluidic applications and devices having confined liquid films. PMID:27221211

  15. Edge states in confined active fluids

    NASA Astrophysics Data System (ADS)

    Souslov, Anton; Vitelli, Vincenzo

    Recently, topologically protected edge modes have been proposed and realized in both mechanical and acoustic metamaterials. In one class of such metamaterials, Time-Reversal Symmetry is broken, and, to achieve this TRS breaking in mechanical and acoustic systems, an external energy input must be used. For example, motors provide a driving force that uses energy and, thus, explicitly break TRS. As a result, motors have been used as an essential component in the design of topological metamaterials. By contrast, we explore the design of topological metamaterials that use a class of far-from-equilibrium liquids, called polar active liquids, that spontaneously break TRS. We thus envision the confinement of a polar active liquid to a prescribed geometry in order to realize topological order with broken time-reversal symmetry. We address the design of the requisite geometries, for example a regular honeycomb lattice composed of annular channels, in which the active liquid may be confined. We also consider the physical character of the active liquid that, when introduced into the prescribed geometry, will spontaneously form the flow pattern of a metamaterial with topologically protected edge states. Finally, we comment on potential experimental realizations of such metamaterials.

  16. Spin-Orbit Activated Confinement Resonances

    NASA Astrophysics Data System (ADS)

    Keating, David; Manson, Steven; Deshmukh, Pranawa

    2016-05-01

    At high enough Z relativistic effects become important contributors to even the qualitative nature of atomic properties. This is likely to be true for confined atoms as well. One relativistic effect of interest is the spin-orbit activated interchannel coupling of a pair of spin-orbit doublet channels. This interaction is possible owing to the spin-orbit interaction breaking the degenerancy among the electrons of a subshell allowing, for example, the 5p3/2 and 5p1/2 subshells of mercury (Z = 80) and the 6p3/2 and 6p1/2 of radon (Z = 86), to interact. To explore the effect confinement has on spin-orbit activated interchannel coupling, a theoretical study of the 5p subshell of mercury and the 6p subshell of radon both confined in a C60 cage has been performed using the relativistic-random-phase approximation (RRPA) methodology. The effects of the C60 potential modeled by a static spherical well which is reasonable in the energy region well above the C60 plasmons. It is found in the photoionization cross sections of the 5p3/2 of confined mercury and the 6p3/2 of confined radon an extra confinement resonance due to spin-orbit activated interchannel coupling with the respective np1/2 photoionization channels.

  17. Effective diffusion of confined active Brownian swimmers.

    PubMed

    Sandoval, Mario; Dagdug, Leornardo

    2014-12-01

    We theoretically find the effect of confinement and thermal fluctuations on the diffusivity of a spherical active swimmer moving inside a two-dimensional narrow cavity of general shape. The explicit formulas for the effective diffusion coefficient of a swimmer moving inside two particular cavities are presented. We also compare our analytical results with Brownian dynamics simulations and we obtain excellent agreement. PMID:25615133

  18. Effective diffusion of confined active Brownian swimmers

    NASA Astrophysics Data System (ADS)

    Sandoval, Mario; Dagdug, Leonardo

    2014-11-01

    We find theoretically the effect of confinement and thermal fluctuations, on the diffusivity of a spherical active swimmer moving inside a two-dimensional narrow cavity of general shape. The explicit formulas for the effective diffusion coefficient of a swimmer moving inside two particular cavities are presented. We also compare our analytical results with Brownian Dynamics simulations and we obtain excellent agreement. L.D. thanks Consejo Nacional de Ciencia y Tecnologia (CONACyT) Mexico, for partial support by Grant No. 176452. M. S. thanks CONACyT and Programa de Mejoramiento de Profesorado (PROMEP) for partially funding this work under Grant No. 103.5/13/6732.

  19. Neutron Assay System for Confinement Vessel Disposition

    SciTech Connect

    Frame, Katherine C.; Bourne, Mark M.; Crooks, William J.; Evans, Louise; Mayo, Douglas R.; Miko, David K.; Salazar, William R.; Stange, Sy; Valdez, Jose I.; Vigil, Georgiana M.

    2012-07-13

    Los Alamos National Laboratory has a number of spherical confinement vessels (CVs) remaining from tests involving nuclear materials. These vessels have an inner diameter of 6 feet with 1-inch thick steel walls. The goal of the Confinement Vessel Disposition (CVD) project is to remove debris and reduce contamination inside the CVs. The Confinement Vessel Assay System (CVAS) was developed to measure the amount of special nuclear material (SNM) in CVs before and after cleanout. Prior to cleanout, the system will be used to perform a verification measurement of each vessel. After cleanout, the system will be used to perform safeguards-quality assays of {le}100-g {sup 239}Pu equivalent in a vessel for safeguards termination. The CVAS has been tested and calibrated in preparation for verification and safeguards measurements.

  20. Confined systems within arbitrary enclosed surfaces

    NASA Astrophysics Data System (ADS)

    Burrows, B. L.; Cohen, M.

    2016-06-01

    A new model of electronic confinement in atoms and molecules is presented. This is based on the electronic flux J which is assumed to vanish on some notional bounding surface of arbitrary shape. J is necessarily calculated using an approximate wave-function, whose parameters are chosen to satisfy the required surface conditions. This model embraces the results of all previous calculations for which the wave-functions or their derivatives vanish on conveniently shaped surfaces, but now extends the theory to more general surfaces. Examples include one-centre hydrogen-like atoms, the valence state of Li and the two centre molecular systems {{{H}}}2+ and {{HeH}}++.

  1. Neutron Assay System for Confinement Vessel Disposition

    SciTech Connect

    Frame, Katherine C; Bourne, Mark M; Crooks, William J; Evans, Louise; Mayo, Douglas R; Miko, David K; Salazar, William R; Stange, Sy; Valdez, Jose I; Vigil, Georgiana M

    2012-07-13

    Waste will be removed from confinement vessels remaining from 1970s-era experiments. Los Alamos has 9+ spherical confinement vessels remaining from experiments. Each vessel contains {approx} 500 lbs of radioactive debris such as actinide metals and oxides, metals, powdered silica, graphite, and wires and hardware. In order to dispose of the vessels, debris and contamination must be removed. Neutron assay system was designed to assay vessels before and after cleanout. System requirements are: (1) Modular and moveable; (2) Capable of detecting {approx}100g {sup 239}Pu equivalent in a 2-inch thick steel sphere with 6 foot diameter; and (3) Capable of safeguards-quality assays. Initial design parameters arethe use of 4-atm {sup 3}He tubes with length of 6 feet, and {sup 3}He tubes embedded in polyethelene for moderation. This paper describes the calibration of the Confinement Vessel Assay System (CVAS) and quantification of its uncertainties. Assay uncertainty depends on five factors: (1) Statistical uncertainty in the assay measurement; (2) Statistical uncertainty in the background measurement; (3) Statistical uncertainty in the isotopics determination - This should be much smaller than the other uncertainties; (4) Systematic uncertainty due to position bias; and (5) Systematic uncertainty due to fluctuations in cosmic ray spallation. This one can be virtually eliminated by performing the background measurement with an empty vessel - but that may not be possible. We used modeling and experiments to quantify the systematic uncertainties. The calibration assumes a uniform distribution of material, but reality will be different. MCNPX modeling was used to quantify the positional bias. The model was benchmarked to build confidence in its results. Material at top of vessel is 44% greater than amount assayed, according to singles. Material near 19-tube detector is 38% less than amount assayed, according to singles. Cosmic ray spallation contributes significantly to the

  2. Domain nucleation and confinement in agent-controlled bistable systems

    NASA Astrophysics Data System (ADS)

    Battogtokh, Dorjsuren

    2015-03-01

    We report a mechanism of pattern formation in growing bistable systems coupled indirectly. A modified Fujita et al. model is studied as an example of a reaction-diffusion system of nondiffusive activator and inhibitor molecules immersed in the medium of a fast diffusive agent. Here we show that, as the system grows, a new domain nucleates spontaneously in the area where the local level of the agent becomes critical. Newly nucleated domains are stable and the pattern formation is different from Turing's mechanism in monostable systems. Domains are spatially confined by the agent even if the activator and inhibitor molecules diffuse. With the spatial extension of the system, a larger domain may undergo a wave number instability, and the concentrations of active molecules within the neighboring elements of a domain can become sharply different. The mechanism reported in this work could be generic for pattern formation systems involving multistability, growth, and indirect coupling.

  3. Confinement and Tritium Stripping Systems for APT Tritium Processing

    SciTech Connect

    Hsu, R.H.; Heung, L.K.

    1997-10-20

    This report identifies functions and requirements for the tritium process confinement and clean-up system (PCCS) and provides supporting technical information for the selection and design of tritium confinement, clean-up (stripping) and recovery technologies for new tritium processing facilities in the Accelerator for the Production of Tritium (APT). The results of a survey of tritium confinement and clean-up systems for large-scale tritium handling facilities and recommendations for the APT are also presented.

  4. Orientational order in two-dimensional confined active suspensions

    NASA Astrophysics Data System (ADS)

    Tsang, Alan Cheng Hou; Kanso, Eva

    2013-11-01

    Geometric confinement in physical space is important for the studies of the collective motion of active suspensions. The reasons are two-fold: motile biological micro-organisms or active collides are always subject to different types of confinement in their swimming environment; The existence of confinement can significantly affects hydrodynamic interactions between the swimmers and thus changes the nature of collective motion. We focus on the situation when the swimmers are confined between two parallel plates such that the motion of the particles are restricted to two dimensions. In this case, the far-field hydrodynamic effect of a swimmer is no longer given by a force-dipole, which has been used in numerous studies on discrete numerical simulations and continuum theories. Instead, the far-field effect of a confined swimmer is given by a potential-dipole. Using a potential-dipole model in doubly-periodic domain, we perform numerical simulations to probe into the collective dynamics of confined active suspensions. We show that isotropic suspensions of swimmers are unstable and develop long time polar orientation order. This results in coherent clusters swimming in the same direction, reminiscent to the collective behavior usually observed in phenomenological models.

  5. Effect of hydrodynamic interactions in confined active suspensions

    NASA Astrophysics Data System (ADS)

    Ezhilan, Barath; Saintillan, David

    2014-11-01

    The dynamics of biologically active suspensions in confined geometries is investigated by incorporating accurate boundary conditions within the kinetic theory framework [Saintillan and Shelley, Phys. Fluids. (2008)]. Even in the absence of wall hydrodynamic interactions or imposed flow, swimming microorganisms have a tendency to accumulate at confining boundaries due to self-propulsion. Satisfying a zero wall-normal translational flux condition on the active particle probability distribution function captures this effect. Using a moment-closure approximation, analytical expressions for the equilibrium concentration/polarization profiles are derived in the dilute limit. As particle density increases, we expect particle-particle hydrodynamic interactions to become significant and to destabilize these equilibrium distributions. Using a linear stability analysis and 3D finite volume simulation of the equations for the orientational moments, we study in detail the effect of fluid coupling on the stability properties of the equilibrium states in confined active suspensions.

  6. The Active Bacterial Community in a Pristine Confined Aquifer

    EPA Science Inventory

    This study of the active bacteria residing in a pristine confined aquifer provides unexpected insights into the ecology of iron-reducing and sulfate-reducing bacteria in the subsurface. At 18 wells in east-central Illinois, we trapped the microbes that attached to aquifer sedimen...

  7. Exact Solutions for Confined Model Systems Using Kummer Functions

    NASA Astrophysics Data System (ADS)

    Burrows, B. L.; Cohen, M.

    We treat model systems where an electron is confined in a region of space. The particular models considered have solutions which may be expressed in terms of the Kummer functions. Both standard and non-standard Kummer functions are used in these models and a comprehensive summary of the usual and exceptional Kummer functions is given. The definition of confinement is widened to treat radial confinement in any spherical shell, including the asymptotic region and cases where the electron is confined to a lower dimension. Initially we consider the theory in K dimensional space and then give particular examples in 1, 2, and 3 dimensions. A commonly treated model is the radially confined hydrogen atom in 3 dimensions with an infinite barrier on a confining sphere so that the wavefunction is identically zero on this sphere. We have extended this model to treat a more general model of spherical confinement where the derivative of the charge density is zero on the confining sphere. It is shown that the analogous models for the radial harmonic oscillator and radial constant potentials may be treated using a generic technique.

  8. Normal modes of confined cold ionic systems

    SciTech Connect

    Schiffer, J.P.; Dubin, D.H.

    1995-08-01

    The normal modes of a cloud of confined ions forming a strongly-correlated plasma were investigated. The results of molecular-dynamics simulations were compared to predictions of a cold fluid mode. Mode frequencies are observed to shift slightly compared to the cold fluid predictions, and the modes are also observed to damp in time. Simulations also reveal a set of torsional oscillations which have no counterpart in cold fluid theory. The frequency shift, damping, and torsional effects are compared to a model that treats trapped plasmas as a visco-elastic spheroid. It may be possible to measure high-frequency bulk and shear moduli of a strongly-correlated plasma from mode excitation experiments on trapped non-neutral plasmas. An example of the results of the calculation is presented.

  9. Restricted dynamics of molecular hydrogen confined in activated carbon nanopores

    SciTech Connect

    Contescu, Cristian I; Saha, Dipendu; Gallego, Nidia C; Mamontov, Eugene; Kolesnikov, Alexander I; Bhat, Vinay V

    2012-01-01

    Quasi-elastic neutron scattering was used for characterization of dynamics of molecular hydrogen confined in narrow nanopores of two activated carbon materials: PFAC (derived from polyfurfuryl alcohol) and UMC (ultramicroporous carbon). Fast, but incomplete ortho-para conversion was observed at 10 K, suggesting that scattering originates from the fraction of unconverted ortho isomer which is rotation-hindered because of confinement in nanopores. Hydrogen molecules entrapped in narrow nanopores (<7 ) were immobile below 22-25 K. Mobility increased rapidly with temperature above this threshold, which is 8 K higher than the melting point of bulk hydrogen. Diffusion obeyed fixed-jump length mechanism, indistinguishable between 2D and 3D processes. Thermal activation of diffusion was characterized between ~22 and 37 K, and structure-dependent differences were found between the two carbons. Activation energy of diffusion was higher than that of bulk solid hydrogen. Classical notions of liquid and solid do not longer apply for H2 confined in narrow nanopores.

  10. Novel phenomena in confined electronic systems

    NASA Astrophysics Data System (ADS)

    Roostaei, Bahman

    Modern experimental methods have made it possible for physicists to investigate matter in extreme conditions. Two of the most extreme conditions are low temperature and low dimensionality. Fabricated semiconductor or metal nano-ring arrays and narrow quantum wells in semiconductor heterostructures at low temperatures provide such an extreme environments for electrons. I will explain these systems in this dissertation. Quantum Wells. In a closely spaced double quantum well (DQW), electrons are thought to form an interlayer coherent state when a perpendicular magnetic field is applied such that the total Landau level filling factor one. The low energy topological excitations of the electron gas in these structures includes charged pseudo-spin vortices and anti-vortices. By calculating the energy per electron and the electron densities in the Hartree-Fock approximation, we show that there are new excited states with interwoven spin and pseudo-spin and that their presence in the system can explain new experimental results. The excitations of DQW's (called merons) also have important effects on transport in these systems. These objects carry charge, vorticity, and electric dipole moment. Disorder is likely to unbind them and allow them to diffuse through the system independently. Due to their different dipole moments, the various types of merons may then in principle be distinguished in transport activation energies by an interlayer bias potential. We explore the dynamics of merons using Chern-Simon theory for quantum Hall systems. We numerically estimate their energies in various circumstances and compare them to the recent experiments. Nano-rings. In this dissertation we also fully analyze the possible phases of a model of singly charged one and two dimensional arrays of rings each having a diameter " 100 nm. Using the Hartree approximation and Monte-Carlo simulations we demonstrate that the electrostatic polarization of these arrays undergoes a quantum phase

  11. EDITORIAL: Energetic particles in magnetic confinement systems

    NASA Astrophysics Data System (ADS)

    Toi, K.

    2006-10-01

    Energetic alpha particle physics plays an obviously crucial role in burning fusion plasmas. Good confinement of them is required to sustain fusion burn and to avoid damage of the first wall. Because of this importance for nuclear fusion research, Y. Kolesnichenko and the late D. Sigmar initiated a series of IAEA technical (committee) meetings (TCM, since the 8th meeting TM) in order to exchange information on the behaviour of energetic particles in magnetic confinement devices. The role of the TMs has become increasingly important since burning plasma projects such as ITER are in preparation. After every TM, invited speakers are encouraged to publish an adapted and extended version of their contributions to the meeting as an article in a special issue of Nuclear Fusion. An exception was the 8th TM the articles of which were published in a special issue of Plasma Physics and Controlled Fusion (2004 46 S1-118). These special issues attract much interest in the subject. The 9th IAEA TM of this series was held in Takayama, Japan, 9-11 November 2005, and 53 papers including 16 invited talks were presented. A total of 11 papers based on these invited talks are included in this special issue of Nuclear Fusion and are preceded by a conference summary. Experimental results of energetic ion driven global instabilities such as Alfvén eigenmodes (AEs), energetic particle modes (EPMs) and fishbone instabilities were presented from several tokamaks (JET, JT-60U, DIII-D and ASDEX Upgrade), helical/stellarator devices (LHD and CHS) and spherical tori (NSTX and MAST). Experimental studies from JET and T-10 tokamaks on the interaction of ion cyclotron waves with energetic ions and runaway electrons were also presented. Theoretical works on AEs, EPMs and nonlinear phenomena induced by energetic particles were presented and compared with experimental data. Extensive numerical codes have been developed and applied to obtain predictions of energetic particle behaviour in future ITER

  12. Confined polyelectrolytes: The complexity of a simple system.

    PubMed

    Nunes, Sandra C C; Skepö, Marie; Pais, Alberto A C C

    2015-08-01

    The interaction between polyelectrolytes and counterions in confined situations and the mutual relationship between chain conformation and ion condensation is an important issue in several areas. In the biological field, it assumes particular relevance in the understanding of the packaging of nucleic acids, which is crucial in the design of gene delivery systems. In this work, a simple coarse-grained model is used to assess the cooperativity between conformational change and ion condensation in spherically confined backbones, with capsides permeable to the counterions. It is seen that the variation on the degree of condensation depends on counterion valence. For monovalent counterions, the degree of condensation passes through a minimum before increasing as the confining space diminishes. In contrast, for trivalent ions, the overall tendency is to decrease the degree of condensation as the confinement space also decreases. Most of the particles reside close to the spherical wall, even for systems in which the density is higher closer to the cavity center. This effect is more pronounced, when monovalent counterions are present. Additionally, there are clear variations in the charge along the concentric layers that cannot be totally ascribed to polyelectrolyte behavior, as shown by decoupling the chain into monomers. If both chain and counterions are confined, the formation of a counterion rich region immediately before the wall is observed. Spool and doughnut-like structures are formed for stiff chains, within a nontrivial evolution with increasing confinement. PMID:26096545

  13. Load-Induced Confinement Activates Diamond Lubrication by Water

    NASA Astrophysics Data System (ADS)

    Zilibotti, G.; Corni, S.; Righi, M. C.

    2013-10-01

    Tribochemical reactions are chemical processes, usually involving lubricant or environment molecules, activated at the interface between two solids in relative motion. They are difficult to be monitored in situ, which leaves a gap in the atomistic understanding required for their control. Here we report the real-time atomistic description of the tribochemical reactions occurring at the interface between two diamond films in relative motion, by means of large scale ab initio molecular dynamics. We show that the load-induced confinement is able to catalyze diamond passivation by water dissociative adsorption. Such passivation decreases the energy of the contacting surfaces and increases their electronic repulsion. At sufficiently high coverages, the latter prevents surface sealing, thus lowering friction. Our findings elucidate effects of the nanoscale confinement on reaction kinetics and surface thermodynamics, which are important for the design of new lubricants.

  14. Theory of Activated Relaxation in Nanoscale Confined Liquids

    NASA Astrophysics Data System (ADS)

    Mirigian, Stephen; Schweizer, Kenneth

    2014-03-01

    We extend the recently developed Elastically Cooperative Nonlinear Langevin Equation(ECNLE) theory of activated relaxation in supercooled liquids to treat the case of geometrically confined liquids. Generically, confinement of supercooled liquids leads to a speeding up of the dynamics(with a consequent depression of the glass transition temperature) extending on the order of tens of molecular diameters away from a free surface. At present, this behavior is not theoretically well understood. Our theory interprets the speed up in dynamics in terms of two coupled effects. First, a direct surface effect, extending two to three molecular diameters from a free surface, and related to a local rearrangement of molecules with a single cage. The second is a longer ranged ``confinement'' effect, extending tens of molecular diameters from a free surface and related to the long range elastic penalty necessary for a local rearrangement. The theory allows for the calculation of relaxation time and Tg profiles within a given geometry and first principles calculations of relevant length scales. Comparison to both dynamic and pseudo-thermodynamic measurements shows reasonable agreement to experiment with no adjustable parameters.

  15. MHD-stable plasma confinement in an axisymmetric mirror system

    SciTech Connect

    Stupakov, G.V.

    1988-02-01

    If the magnetic field of a nonparaxial mirror system is chosen appropriately, it is possible to maintain a sharp plasma boundary in an open axisymmetric confinement system in a manner which is stable against flute modes (both global and small-scale). Stability prevails in the ideal MHD approximation without finite-ion-Larmor radius effects.

  16. Singularity confinement and chaos in two-dimensional discrete systems

    NASA Astrophysics Data System (ADS)

    Kanki, Masataka; Mase, Takafumi; Tokihiro, Tetsuji

    2016-06-01

    We present a quasi-integrable two-dimensional lattice equation: i.e., a partial difference equation which satisfies a test for integrability, singularity confinement, although it has a chaotic aspect in the sense that the degrees of its iterates exhibit exponential growth. By systematic reduction to one-dimensional systems, it gives a hierarchy of ordinary difference equations with confined singularities, but with positive algebraic entropy including a generalized form of the Hietarinta–Viallet mapping. We believe that this is the first example of such quasi-integrable equations defined over a two-dimensional lattice.

  17. Magnetic confinement system using charged ammonia targets

    DOEpatents

    Porter, Gary D.; Bogdanoff, Anatoly

    1979-01-01

    A system for guiding charged laser targets to a predetermined focal spot of a laser along generally arbitrary, and especially horizontal, directions which comprises a series of electrostatic sensors which provide inputs to a computer for real time calculation of position, velocity, and direction of the target along an initial injection trajectory, and a set of electrostatic deflection means, energized according to a calculated output of said computer, to change the target trajectory to intercept the focal spot of the laser which is triggered so as to illuminate the target of the focal spot.

  18. An electrostatically and a magnetically confined electron gun lens system

    NASA Technical Reports Server (NTRS)

    Bernius, Mark T.; Man, Kin F.; Chutjian, Ara

    1988-01-01

    Focal properties, electron trajectory calculations, and geometries are given for two electron 'gun' lens systems that have a variety of applications in, for example, electron-neutral and electron-ion scattering experiments. One nine-lens system utilizes only electrostatic confinement and is capable of focusing electrons onto a fixed target with extremely small divergence angles, over a range of final energies 1-790 eV. The second gun lens system is a simpler three-lens system suitable for use in a uniform, solenoidal magnetic field. While the focusing properties of such a magnetically confined lens systenm are simpler to deal with, the system does illustrate features of electron extraction and Brillouin flow that have not been suitably emphasized in the literature.

  19. Mirror confinement systems: Final technical report

    SciTech Connect

    Not Available

    1988-08-01

    This report contains: (1) A discussion of azimuthal asymmetrics and fluctuations in RFC-XX-M. Both lead to enhanced radial transport in RFC-XX-M, and presumably most other tandem mirror machines as well; A report on four operating modes of RFC-XX-M which were developed and studied as part of the collaboration. These operating modes were the simple tandem mode, the negative (floating) potential mode, the hot electron mode, and the ECH (electron cyclotron heating) mode; A pulsed rf heated discharge cleaning system which was developed for RFC-XX-M. This method of cleaning proved much more effective than normal glow discharge cleaning, and variations of it are currently in use on the GAMMA-10 tandem mirror and the JIPP TII-U tokamak at the Institute for Plasma Physics at Nagoya; Short descriptions of the diagnostics development and improvement done in conjunction with the work on RFC-XX-M; and a compilation of the work performed at the University of Tsukuba on GAMMA-10. Most of the effort on GAMMA-10 involved diagnostics development and improvement. 16 refs., 42 figs., 1 tab.

  20. Magnetically confined plasma solar collector. [satellite based system in space

    NASA Technical Reports Server (NTRS)

    Walters, C. T.; Wolken, G., Jr.; Purvis, G. D., III

    1978-01-01

    The possibility of using a plasma medium for collecting solar energy in space is examined on the basis of a concept involving an orbiting magnetic bottle in which a solar-energy-absorbing plasma is confined. A basic system uses monatomic cesium as working fluid. Cesium evaporates from a source and flows into the useful volume of a magnetic bottle where it is photoionized by solar radiation. Ions and electrons lost through the loss cones are processed by a recovery system, which might be a combination of electromagnetic devices and heat engines. This study concentrates on the plasma production processes and size requirements, estimates of the magnetic field required to confine the plasma, and an estimate of the system parameters for a 10 GW solar collector using cesium.

  1. Radiation and confinement in 0D fusion systems codes

    NASA Astrophysics Data System (ADS)

    Lux, H.; Kemp, R.; Fable, E.; Wenninger, R.

    2016-07-01

    In systems modelling for fusion power plants, it is essential to robustly predict the performance of a given machine design (including its respective operating scenario). One measure of machine performance is the energy confinement time {τ\\text{E}} that is typically predicted from experimentally derived confinement scaling laws (e.g. IPB98(y,2)). However, the conventionally used scaling laws have been derived for ITER which—unlike a fusion power plant—will not have significant radiation inside the separatrix. In the absence of a new high core radiation relevant confinement scaling, we propose an ad hoc correction to the loss power {{P}\\text{L}} used in the ITER confinement scaling and the calculation of the stored energy {{W}\\text{th}} by the radiation losses from the ‘core’ of the plasma {{P}\\text{rad,\\text{core}}} . Using detailed ASTRA / TGLF simulations, we find that an appropriate definition of {{P}\\text{rad,\\text{core}}} is given by 60% of all radiative losses inside a normalised minor radius {ρ\\text{core}}=0.75 . We consider this an improvement for current design predictions, but it is far from an ideal solution. We therefore encourage more detailed experimental and theoretical work on this issue.

  2. Confinement Vessel Assay System: Design and Implementation Report

    SciTech Connect

    Frame, Katherine C.; Bourne, Mark M.; Crooks, William J.; Evans, Louise; Mayo, Douglas R.; Gomez, Cipriano D.; Miko, David K.; Salazar, William R.; Stange, Sy; Vigil, Georgiana M.

    2012-07-18

    Los Alamos National Laboratory has a number of spherical confinement vessels remaining from tests involving nuclear materials. These vessels have an inner diameter of 6 feet with 1- to 2-inch thick steel walls. The goal of the Confinement Vessel Disposition (CVD) project is to remove debris and reduce contamination inside the vessels. We have developed a neutron assay system for the purposes of Materials Control and Accountability (MC&A) measurements of the vessel prior to and after cleanout. We present our approach to confronting the challenges in designing, building, and testing such a system. The system was designed to meet a set of functional and operational requirements. A Monte Carlo model was developed to aid in optimizing the detector design as well as to predict the systematic uncertainty associated with confinement vessel measurements. Initial testing was performed to optimize and determine various measurement parameters, and then the system was characterized using {sup 252}Cf placed a various locations throughout the measurement system. Measurements were also performed with a {sup 252}Cf source placed inside of small steel and HDPE shells to study the effect of moderation. These measurements compare favorably with their MCNPX model equivalent, making us confident that we can rely on the Monte Carlo simulation to predict the systematic uncertainty due to variations in response to material that may be localized at different points within a vessel.

  3. Confinement Vessel Assay System: Calibration and Certification Report

    SciTech Connect

    Frame, Katherine C.; Bourne, Mark M.; Crooks, William J.; Evans, Louise; Gomez, Cipriano; Mayo, Douglas R.; Miko, David K.; Salazar, William R.; Stange, Sy; Vigil, Georgiana M.

    2012-07-17

    Los Alamos National Laboratory has a number of spherical confinement vessels (CVs) remaining from tests involving nuclear materials. These vessels have an inner diameter of 6 feet with 1 to 2 inch thick steel walls. The goal of the Confinement Vessel Disposition (CVD) project is to remove debris and reduce contamination inside the vessels. The Confinement Vessel Assay System (CVAS) was developed to measure the amount of SNM in CVs before and after cleanout. Prior to cleanout, the system will be used to perform a verification measurement of each vessel. After cleanout, the system will be used to perform safeguards-quality assays of {le} 100-g {sup 239}Pu equivalent in a vessel for safeguards termination. The system was calibrated in three different mass regions (low, medium, and high) to cover the entire plutonium mass range that will be assayed. The low mass calibration and medium mass calibration were verified for material positioned in the center of an empty vessel. The systematic uncertainty due to position bias was estimated using an MCNPX model to simulate the response of the system to material localized at various points along the inner surface of the vessel. The background component due to cosmic ray spallation was determined by performing measurements of an empty vessel and comparing to measurements in the same location with no vessel present. The CVAS has been tested and calibrated in preparation for verification and safeguards measurements of CVs before and after cleanout.

  4. Nature of ordering in confined crystalline ionic systems

    SciTech Connect

    Schiffer, J.P.

    1995-08-01

    Simulations continued studying the properties of systems of ions confined in ion traps or storage rings and cooled to very low temperatures, forming a strongly correlated non-neutral plasma. In particular the computer simulation of a large system of 20000 ions in isotropic confinement was continued to investigate whether a transition to the body-centered cubic order that is characteristic of infinite systems might occur. The simulations so far have not provided a conclusive answer. The systems show a characteristic shell structure, 18 spherical shells, very similar to what was seen in smaller simulations. Simulations were also done with the same number of ions in anisotropic confinement. Here a surprising result is seen -- instead of forming a series of spheroidal shells, the anisotropy causes the outer shell to be spheroidal -- but the inner ones are formed at a fixed distance from the outermost shell -- giving shapes that are not spheroids and exhibit discontinuous edges. The relevance of these phenomena to ion traps needs to be investigated.

  5. Open-ended magnetic confinement systems for fusion

    SciTech Connect

    Post, R.F.; Ryutov, D.D.

    1995-05-01

    Magnetic confinement systems that use externally generated magnetic fields can be divided topologically into two classes: ``closed`` and `open``. The tokamak, the stellarator, and the reversed-field-pinch approaches are representatives of the first category, while mirror-based systems and their variants are of the second category. While the recent thrust of magnetic fusion research, with its emphasis on the tokamak, has been concentrated on closed geometry, there are significant reasons for the continued pursuit of research into open-ended systems. The paper discusses these reasons, reviews the history and the present status of open-ended systems, and suggests some future directions for the research.

  6. Exploratory activity and habituation of Drosophila in confined domains

    NASA Astrophysics Data System (ADS)

    Soibam, B.; Chen, L.; Roman, G. W.; Gunaratne, G. H.

    2014-09-01

    Animals use locomotion to find food, shelter, and escape routes as well as to locate predators, competitors, and mates. Thus, locomotion is related to many behavioral traits, and can be used to characterize these more complex facets of behavior. Exploratory behaviors are random and need to be assessed through stochastic analysis. By comparing ensembles of trajectories from Drosophila and a model animal, we identify a pair of principles that govern the stochastic motion of a specific species. The first depends on local cues and quantify directional persistence, i.e., the propensity of an animal to maintain direction; the second, its attraction to walls, is relevant for exploration in confined arenas. Statistical properties of exploratory activity in several types of arenas can be computed from these principles. A pair of spiral arenas are designed to demonstrate that centrophobicity, or fear of the center of an arena, is not a fundamental feature of exploration. xxxx We provide evidence to show that the decay in an animal's activity following its introduction into a novel arena is correlated to its familiarity with the arena. We define two measures, coverage and habituation, to quantify familiarity. It is found that the relationship between activity and coverage is independent of the arena size. Finally, we use an analysis of exploration of mutant species to infer that in Drosophila, habituation relies on visual cues.

  7. Catalytic activity and stability of glucose oxidase/horseradish peroxidase co-confined in macroporous silica foam.

    PubMed

    Cao, Xiaodong; Li, Ying; Zhang, Zhiqiang; Yu, Jiachao; Qian, Jing; Liu, Songqin

    2012-12-21

    Investigation of the catalytic activity and stability of enzymes in confined nano/microspace provides valuable contributions to the fundamental understanding of biological reactions taking place on a mesoscopic scale within confined spaces. In this paper, macroporous silica foam (MSF) is used as a nanoreactor to co-confine glucose oxidase (GOD) and horseradish peroxidase (HRP). Then, the enzymatic cascade reactions, which act in tandem inside nanoreactors, for oxidation of glucose and 3,3',5,5'-tetramethylbenzidine (TMB) were studied. The catalytic kinetic parameters of apparent Michaelis constant (K(m)(app)) and maximum rate (V(max)) were obtained from Lineweaver-Burk plot by UV-vis spectrometry. Results showed that the catalytic activity of the co-confined enzymes is reduced compared to that of free enzymes in solution at room temperature. The stabilities of co-confined enzymes in denaturing agents, such as guanidinium chloride (GdmCl) and urea, were higher than those of free enzymes in solution. When employing a co-confined bienzyme system as a biosensor for the detection of glucose, a wider linear range of glucose was obtained for the co-confined bienzyme system than for free enzymes in solution. PMID:23096254

  8. The active bacterial community in a pristine confined aquifer

    NASA Astrophysics Data System (ADS)

    Flynn, Theodore M.; Sanford, Robert A.; Santo Domingo, Jorge W.; Ashbolt, Nicholas J.; Levine, Audrey D.; Bethke, Craig M.

    2012-09-01

    This study of the active bacteria residing in a pristine confined aquifer provides unexpected insights into the ecology of iron-reducing and sulfate-reducing bacteria in the subsurface. At 18 wells, we trapped the microbes that attached to aquifer sediment and used molecular techniques to examine the bacterial populations. We used multivariate statistics to compare the composition of bacterial communities among the wells with respect to the chemistry of the groundwater. We found groundwater at each well was considerably richer in ferrous iron than sulfide, indicating iron-reducing bacteria should, by established criteria, dominate the sulfate reducers. Our results show, however, that areas where groundwater contains more than a negligible amount of sulfate (>0.03 mM), populations related to sulfate reducers of the generaDesulfobacter and Desulfobulbus were of nearly equal abundance with putative iron reducers related to Geobacter, Geothrix, and Desulfuromonas. Whereas sulfate is a key discriminant of bacterial community structure, we observed no statistical relationship between the distribution of bacterial populations in this aquifer and the concentration of either ferrous iron or dissolved sulfide. These results call into question the validity of using the relative concentration of these two ions to predict the nature of bacterial activity in an aquifer. Sulfate reducers and iron reducers do not appear to be segregated into discrete zones in the aquifer, as would be predicted by the theory of competitive exclusion. Instead, we find the two groups coexist in the subsurface in what we suggest is a mutualistic relationship.

  9. Antimatter Assisted Inertial Confinement Fusion Propulsion Systems for Interstellar Missions

    NASA Astrophysics Data System (ADS)

    Halyard, R. J.

    Current developments such as the Ion Compressed Antimatter Nuclear (ICAN-II) propulsion system proposed by the Pennsylvania State University Center for Space Propulsion Engineering open the way to the possible use of available supplies of antiprotons to power antimatter assisted inertial confinement fusion (AAICF) propulsion systems for interstellar missions. Analysis indicates that light weight AAICF propulsion systems with specific impulses in excess of seven hundred thousand seconds may be feasible within the next 30 years. AAICF should prove to be the optimum propulsion system since it possesses high thrust, low weight and high exhaust velocity. The purpose of this paper is to evaluate the potential of AAICF propulsion for interstellar missions such as NASA Administrator Dan Goldin's Alpha Centauri Flyby and a Barnard's Star Orbital Mission, and to compare these projections with previous performance estimates for ICF Laser Beam propulsion systems.

  10. Program status 1. quarter -- FY 1989: Confinement systems programs

    SciTech Connect

    1989-01-20

    Brief summaries are given for DIII-D Research Operations covering the following areas: beta and stability; confinement; boundary physics; electron cyclotron heating; ion Bernstein wave heating; current drive; tokamak operations; neutral beam operations; ECH operations; ICH operations; computer data systems; program development; and hardware development. The progress summaries on the International Cooperation task are given for the Tora Supra, HIDEX -- Nagoya Tokamak Experiment, ASDEX, JET, JFT-2M, CHS, and JT-60. Finally a brief summary of progress on the CIT physics task is given.

  11. Non-unique monopole oscillations of harmonically confined Yukawa systems

    NASA Astrophysics Data System (ADS)

    Ducatman, Samuel; Henning, Christian; Kaehlert, Hanno; Bonitz, Michael

    2008-11-01

    Recently it was shown that the Breathing Mode (BM), the mode of uniform radial expansion and contraction, which is well known from harmonically confined Coulomb systems [1], does not exist in general for other systems [2]. As a consequence the monopole oscillation (MO), the radial collective excitation, is not unique, but there are several MO with different frequencies. Within this work we show simulation results of those monopole oscillations of 2-dimensional harmonically confined Yukawa systems, which are known from, e.g., dusty plasma crystals [3,4]. We present the corresponding spectrum of the particle motion, including analysis of the frequencies found, and compare with theoretical investigations.[1] D.H.E. Dubin and J.P. Schiffer, Phys. Rev. E 53, 5249 (1996)[2] C. Henning at al., accepted for publication in Phys. Rev. Lett. (2008)[3] A. Melzer et al., Phys. Rev. Lett. 87, 115002 (2001)[4] M. Bonitz et al., Phys. Rev. Lett. 96, 075001 (2006)

  12. Quench dynamics in confined 1 + 1-dimensional systems

    NASA Astrophysics Data System (ADS)

    Engelhardt, Dalit

    2016-03-01

    We present a framework for investigating the response of conformally invariant confined 1 + 1-dimensional systems to a quantum quench. While conformal invariance is generally destroyed in a global quantum quench, systems that can be described as or mapped to integrable deformations of a CFT may present special instances where a conformal field theory-based analysis could provide useful insight into the non-equilibrium dynamics. We investigate this possibility by considering a quench analogous to that of the quantum Newton’s Cradle experiment (Kinoshita et al 2006 Nature 440 900) and demonstrating qualitative agreement between observables derived in the CFT framework and those of the experimental system. We propose that this agreement may be a feature of the proximity of the experimental system to an integrable deformation of a c = 1 CFT.

  13. System and method of operating toroidal magnetic confinement devices

    DOEpatents

    Chance, M.S.; Jardin, S.C.; Stix, T.H.; Grimm, R.C.; Manickam, J.; Okabayashi, M.

    1984-08-30

    This invention pertains to methods and arrangements for attaining high beta values in plasma confinement devices. More specifically, this invention pertains to methods for accessing the second stability region of operation in toroidal magnetic confinement devices.

  14. Confinement-induced resonances in ultracold atom-ion systems

    NASA Astrophysics Data System (ADS)

    Melezhik, V. S.; Negretti, A.

    2016-08-01

    We investigate confinement-induced resonances in a system composed of a tightly trapped ion and a moving atom in a waveguide. We determine the conditions for the appearance of such resonances in a broad region—from the "long-wavelength" limit to the opposite case when the typical length scale of the atom-ion polarization potential essentially exceeds the transverse waveguide width. We find considerable dependence of the resonance position on the atomic mass which, however, disappears in the "long-wavelength and zero-energy" limit, where the known result for the confined atom-atom scattering is reproduced. We also derive an analytic and a semianalytic formula for the resonance position in the long-wavelength and zero-energy limit and we investigate numerically the dependence of the resonance condition on the finite atomic colliding energy. Our results, which can be investigated experimentally in the near future, could be used to determine the atom-ion scattering length, to determine the temperature of the atomic ensemble in the presence of an ion impurity, and to control the atom-phonon coupling in a linear ion crystal in interaction with a quasi-one-dimensional atomic quantum gas.

  15. Pattern Transitions in Bacterial Oscillating System under Nanofluidic Confinement

    NASA Astrophysics Data System (ADS)

    Shen, Jie-Pan; Chou, Chia-Fu

    2011-03-01

    Successful binary fission in E. coli relies on remarkable oscillatory behavior of the MinCDE protein system to determine the exact division site. The most favorable models to explain this fascinating spatiotemporal regulation on dynamic MinDE pattern formation in cells are based on reaction-diffusion scenario. Although not fully understood, geometric factors caused by bacterial morphology play a crucial role in MinDE dynamics. In the present study, bacteria were cultured, confined and reshaped in various micro/nanofluidic devices, to mimic either curvature changes of cell peripherals. Fluorescence imaging was utilized to detail the mode transitions in multiple MinDE patterns. The understanding of the physics in multiple pattern formations is further complemented via in silico modeling. The study synergizes the join merits of in vivo, in vitro and in silico approaches, to grasp the insight of stochastic dynamics inherited from the noisy mesoscopic biophysics. We acknowledge support from the Foresight Project, Academia Sinica.

  16. Spontaneous ordering and vortex states of active fluids in circular confinement

    NASA Astrophysics Data System (ADS)

    Theillard, Maxime; Ezhilan, Barath; Saintillan, David

    2015-11-01

    Recent experimental, theoretical and simulation studies have shown that confinement can profoundly affect self-organization in active suspensions leading to striking features such as directed fluid pumping in planar confinement, formation of steady and spontaneous vortices in radial confinement. Motivated by this, we study the dynamics in a suspension of biologically active particles confined in spherical geometries using a mean-field kinetic theory for which we developed a novel numerical solver. In the case of circular confinement, we conduct a systematic exploration of the entire parameter space and distinguish 3 broad states: no-flow, stable vortex and chaotic and several interesting sub-states. Our efficient numerical framework is also employed to study 3D effects and dynamics in more complex geometries.

  17. Hydrochemistry and hydrogeologic conditions within the Hanford Site upper basalt confined aquifer system

    SciTech Connect

    Spane, F.A. Jr.; Webber, W.D.

    1995-09-01

    As part of the Hanford Site Ground-Water Surveillance Project, Flow System Characterization Task. Pacific Northwest Laboratory examines the potential for offsite migration of contamination within the upper basalt confined aquifer system for the US Department of Energy (DOE). As part of this activity, groundwater samples were collected over the past 2 years from selected wells completed in the upper Saddle Mountains Basalt. The hydrochemical and isotopic information obtained from these groundwater samples provides hydrologic information concerning the aquifer-flow system. Ideally, when combined with other hydrologic property information, hydrochemical and isotopic data can be used to evaluate the origin and source of groundwater, areal groundwater-flow patterns, residence and groundwater travel time, rock/groundwater reactions, and aquifer intercommunication for the upper basalt confined aquifer system. This report presents the first comprehensive Hanford Site-wide summary of hydrochemical properties for the upper basalt confined aquifer system. This report provides the hydrogeologic characteristics (Section 2.0) and hydrochemical properties (Section 3.0) for groundwater within this system. A detailed description of the range of the identified hydrochemical parameter subgroups for groundwater in the upper basalt confined aquifer system is also presented in Section 3.0. Evidence that is indicative of aquifer contamination/aquifer intercommunication and an assessment of the potential for offsite migration of contaminants in groundwater within the upper basalt aquifer is provided in Section 4.0. The references cited throughout the report are given in Section 5.0. Tables that summarize groundwater sample analysis results for individual test interval/well sites are included in the Appendix.

  18. Dynamical Density Functional Theory and Hydrodynamic Interactions in Confined Systems

    NASA Astrophysics Data System (ADS)

    Goddard, Benjamin; Kalliadasis, Serafim; Nold, Andreas

    Colloidal systems consist of nano-micrometer sized particles suspended in a bath of many more, much smaller and much lighter particles. When the colloidal particles move through the bath, e.g. when driven by external forces such as gravity, flows are induced in the bath. These flows in turn impart forces on the colloid particles. These bath-mediated forces, known as Hydrodynamic Interactions (HI) strongly influence the dynamics of the colloid particles. This is particularly true in confined systems, in which the presence of walls substantially modifies the HI compared to unbounded geometries. For many-particle systems, the number of degrees of freedom prohibit a direct solution of the underlying stochastic equations and a reduced model is necessary. We model such systems through Dynamical Density Functional Theory (DDFT), the computational complexity of which is independent of the number of particles. We include both inter-particle and particle-wall HI, demonstrating both their combined and relative effects. Funded by EPSRC Grant No. EP/L025159/1.

  19. The confinement effect on the activity of Au NPs in polyols oxidation

    DOE PAGESBeta

    Villa, Alberto; Wang, Di; Chan-Thaw, Carine E.; Campisi, Sebastiano; Veith, Gabriel M; Vahlas, Constantin

    2016-01-01

    We demonstrate a confinement effect where gold nanoparticles trapped within N-functionalized carbon nanofibers (N-CNFs) are more active for polyol oxidation and promote selectivity towards di-acid products, whereas AuNPs trapped on the surface produce as a major by-product the one derived from C C cleavage. The behaviour of NPs confined inside the N-CNF channels can be attributed to a different, possibly multiple, coordination of glycerol on the active site

  20. Experiments on Plasma Injection into a Centrifugally Confined System

    NASA Astrophysics Data System (ADS)

    Messer, S.; Bomgardner, R.; Brockington, S.; Case, A.; Witherspoon, F. D.; Uzun-Kaymak, I.; Elton, R.; Young, W.; Teodorescu, C.; Morales, C. H.; Ellis, R. F.

    2009-11-01

    We describe the cross-field injection of plasma into a centrifugally-confined system. Two different types of plasma railgun have been installed on the Maryland Centrifugal Experiment (MCX) in an attempt to drive that plasma's rotation. The initial gun was a coaxial device designed to mitigate the blowby instability. The second one was a MiniRailgun with a rectangular bore oriented so that the MCX magnetic field augments the railgun's internal magnetic field. Tests at HyperV indicate this MiniRailgun reaches much higher densities than the original gun, although muzzle velocity is slightly reduced. We discuss the impact of these guns on MCX for various conditions. Initial results show that even for a 2 kG field, firing the MiniRailgun modifies oscillations of the MCX diamagnetic loops and can impact the core current and voltage. The gun also has a noticeable impact on MCX microwave emissions. These observations suggest plasma enters the MCX system. We also compare diagnostic data collected separately from MCX for these and other guns, focussing primarily on magnetic measurements.

  1. Suppression of Quantum Scattering in Strongly Confined Systems

    SciTech Connect

    Kim, J. I.; Melezhik, V. S.; Schmelcher, P.

    2006-11-10

    We demonstrate that scattering of particles strongly interacting in three dimensions (3D) can be suppressed at low energies in a quasi-one-dimensional (1D) confinement. The underlying mechanism is the interference of the s- and p-wave scattering contributions with large s- and p-wave 3D scattering lengths being a necessary prerequisite. This low-dimensional quantum scattering effect might be useful in 'interacting' quasi-1D ultracold atomic gases, guided atom interferometry, and impurity scattering in strongly confined quantum wire-based electronic devices.

  2. Nitrogen use efficiency in grazed and confinement dairy production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazing and confinement-based dairy operations in industrialised nations continue to intensify. In general, farm numbers are declining, while milk production per cow and reliance on imported feed and fertiliser are increasing. While greater nitrogen (N) input is a key contributor to increasing produ...

  3. An automated scraper system for swine confinement facilities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Odor and air emissions released by some commercial, large swine operations can be a nuisance. Research has shown that some swine confinement buildings can emit significant amounts of odors, hydrogen sulfide (H2S) and other gases, especially from deep pit buildings with long-term manure storage. A m...

  4. Unique Chernobyl Cranes for Deconstruction Activities in the New Safe Confinement - 13542

    SciTech Connect

    Parameswaran, N.A. Vijay; Chornyy, Igor; Owen, Rob; Schmieman, Eric; Kedrowski, Dan

    2013-07-01

    The devastation left behind from the Chernobyl nuclear power plant (ChNPP) Unit 4 accident which occurred on April 26, 1986 presented unparalleled technical challenges to the world engineering and scientific community. One of the largest tasks that are in progress is the design and construction of the New Safe Confinement (NSC). The NSC is an engineered enclosure for the entire object shelter (OS) that includes a suite of process equipment. The process equipment will be used for the dismantling of the destroyed Chernobyl Nuclear Power Plant (ChNPP) Unit. One of the major mechanical handling systems to be installed in the NSC is the Main Cranes System (MCS). The planned decontamination and decommissioning or dismantling (D and D) activities will require the handling of heavily shielded waste disposal casks containing nuclear fuel as well as lifting and transporting extremely large structural elements. These activities, to be performed within the NSC, will require large and sophisticated cranes. The article will focus on the unique design features of the MCS for the D and D activities. (authors)

  5. Inertial confinement fusion reaction chamber and power conversion system study

    SciTech Connect

    Maya, I.; Schultz, K.R.; Battaglia, J.M.; Buksa, J.J.; Creedson, R.L.; Erlandson, O.D.; Levine, H.E.; Roelant, D.F.; Sanchez, H.W.; Schrader, S.A.

    1984-09-01

    GA Technologies has developed a conceptual ICF reactor system based on the Cascade rotating-bed reaction chamber concept. Unique features of the system design include the use of low activation SiC in a reaction chamber constructed of box-shaped tiles held together in compression by prestressing tendons to the vacuum chamber. Circulating Li/sub 2/O granules serve as the tritium breeding and energy transport material, cascading down the sides of the reaction chamber to the power conversion system. The total tritium inventory of the system is 6 kg; tritium recovery is accomplished directly from the granules via the vacuum system. A system for centrifugal throw transport of the hot Li/sub 2/O granules from the reaction chamber to the power conversion system has been developed. A number of issues were evaluated during the course of this study. These include the response of first-layer granules to the intense microexplosion surface heat flux, cost effective fabrication of Li/sub 2/O granules, tritium inventory and recovery issues, the thermodynamics of solids-flow options, vacuum versus helium-medium heat transfer, and the tradeoffs of capital cost versus efficiency for alternate heat exchange and power conversion system option. The resultant design options appear to be economically competitive, safe, and environmentally attractive.

  6. Glucose Infusion into Exercising Dogs after Confinement: Rectal and Active Muscle Temperatures

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Kruk, B.; Nazar, K.; Falecka-Wieczorek, I.; Kaciuba-Uscilko, H.

    1995-01-01

    Intravenous glucose infusion into ambulatory dogs results in attenuation of exercise-induced increase of both rectal and thigh muscle temperatures. That glucose (Glu) infusion attenuates excessive increase in body temperature from restricted activity during confinement deconditioning. Intravenous glucose infusion attenuates the rise in exercise core temperature in deconditioned dogs by a yet undefined mechanism.

  7. PREFACE: International Conference on Optics of Excitons in Confined Systems

    NASA Astrophysics Data System (ADS)

    Viña, Luis; Tejedor, Carlos; Calleja, José M.

    2010-01-01

    The OECS11 (International Conference on Optics of Excitons in Confined Systems) was the eleventh of a very successful series of conferences that started in 1987 in Rome (Italy). Afterwards the conference was held at Naxos (Sicily, Italy, 1991), Montpellier (France, 1993), Cortona (Italy, 1995), Göttingen (Germany, 1997), Ascona (Switzerland, 1999), Montpellier (France, 2001), Lecce (Italy, 2003), Southampton (UK, 2005) and Patti (Sicily, Italy, 2007). It is addressed to scientists who lead fundamental and applied research on the optical properties of excitons in novel condensed-matter nanostructures. The 2009 meeting (7-11 September 2009) has brought together a large representation of the world leading actors in this domain, with the aim of stimulating the exchange of ideas, promoting international collaborations, and coordinating research on the newest exciton-related issues such as quantum information science and exciton quantum-collective phenomena. The meeting has included invited lectures, contributed oral presentations and posters, covering the following general topics: low-dimensional heterostructures: quantum wells, quantum wires and quantum dots polaritons quantum optics with excitons and polaritons many-body effects under coherent and incoherent excitation coherent optical spectroscopy quantum coherence and quantum-phase manipulation Bose-Einstein condensation and other collective phenomena excitons in novel materials The OECS 11 was held at the campus of the Universidad Autónoma de Madrid in Cantoblanco. The scientific program was composed of more than 200 contributions divided into 16 invited talks, 44 oral contributions and 3 poster sessions with a total of 150 presentations. The scientific level of the presentations was guaranteed by a selection process where each contribution was rated by three members of the Program Committee. The Conference has gathered 238 participants from 21 different countries, with the following distribution: Germany (43

  8. Definition and means of maintaining the ventilation system confinement portion of the PFP safety envelope

    SciTech Connect

    Dick, J.D.; Grover, G.A.; O`Brien, P.M., Fluor Daniel Hanford

    1997-03-05

    The Plutonium Finishing Plant Heating Ventilation and Cooling system provides for the confinement of radioactive releases to the environment and provides for the confinement of radioactive contamination within designated zones inside the facility. This document identifies the components and procedures necessary to ensure the HVAC system provides these functions. Appendices E through J provide a snapshot of non-safety class HVAC equipment and need not be updated when the remainder of the document and Appendices A through D are updated.

  9. Activation of micropore-confined sulfur within hierarchical porous carbon for lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Kim, Jung-Joon; Kim, Hee Soo; Ahn, Jihoon; Lee, Kyung Jae; Yoo, Won Cheol; Sung, Yung-Eun

    2016-02-01

    Hierarchical porous carbon is often used in Li-S batteries due to the widely perceived benefits regarding the wide range of pore sizes. However, such notions are based solely on demonstrations of improved cyclic performances, and specific evidence to prove the utilization of the pores is yet to be found. Herein, we report, for the first time, the evidence for gradual activation of micropore-confined sulfur within porous carbon structures. By systematic comparison of microporous and hierarchical porous structures, we show that at sufficiently low current, sulfur infused hierarchical porous structures display a slowly activated and reversible reaction at 1.75 V vs Li/Li+ during discharge. This is in addition to the conventionally reported two voltage plateau at 2.3 and 2.1 V. Furthermore, the effects of LiNO3 decomposition on the system and the electrochemical mechanism behind the activation process is elucidated. Overall, the findings supplement the currently known electrochemical mechanisms occurring within porous structures and pave the way for more efficient utilization of hierarchical porous structures for applications in Li-S batteries.

  10. System and method of operating toroidal magnetic confinement devices

    DOEpatents

    Chance, Morrell S.; Jardin, Stephen C.; Stix, Thomas H.; Grimm, deceased, Ray C.; Manickam, Janardhan; Okabayashi, Michio

    1987-01-01

    For toroidal magnetic confinement devices the second region of stability against ballooning modes can be accessed with controlled operation. Under certain modes of operation, the first and second stability regions may be joined together. Accessing the second region of stability is accomplished by forming a bean-shaped plasma and increasing the indentation until a critical value of indentation is reached. A pusher coil, located at the inner-major-radius side of the device, is engaged to form a bean-shaped poloidal cross-section in the plasma.

  11. Water-biomolecule systems under extreme conditions: from confinement to pressure effects

    NASA Astrophysics Data System (ADS)

    Bellissent-Funel, M.-C.

    Water is a unique liquid, many of whose properties are critical for the continued support of life. In living systems, essential water-related phenomena occur in restricted geometries in cells, and at active sites of proteins and membranes or at their surface. The effects of hydration on equilibrium protein structure and dynamics are fundamental to the relationship between structure and biological function. In particular, the configuration of water molecules near the hydrophilic-hydrophobic interfaces is of considerable relevance. The structure and dynamics of water confined in model systems developing hydrophilic interactions are compared with that of bulk water as determined by hydrophilic interactions are compared with that of bulk water as determined by neutron scattering. It is well known that hydration, internal dynamics, and function in proteins are intimately associated. Studies of dynamics of water molecules at surface of a C-phycocyanin protein are presented.

  12. Radial guiding-center drifts and omnigenity in bumpy-torus confinement systems

    NASA Astrophysics Data System (ADS)

    Hazeltine, R. D.; Catto, P. J.

    1982-07-01

    Collisional transport of a high temperature plasma across the confining field of a bumpy torus magnetic confinement system which depends sensitively upon the functional form of the radial quiding center drift, and thus upon details of the confinement geometry is discussed. A general and relatively explicit formula for the radial drift is derived, using the large aspect-ratio results of a previous equilibrium study. Allowance is made for: (1) arbitrary toroidal variation of the confining field; (2) field distortion due to plasma currents; (3) noncircular deformation of the toroidal field coils. The analysis pertains only to the plasma core, and not to the high beta annuli (electron rings) which are usually present in experiments. The question of bumpy torus omnigenity whether any bumpy torus field configuration is consistent with a vanishing, or nearly vanishing, radial drift, is also investigated. It is found that omnigenity does not occur in the vicinity of the magnetic axis.

  13. Economic and environmental issues associated with confinement and pasture-based dairy systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Milk is produced in a continuum of dairy systems from full confinement to full pasture grazing. Climate, available feeds, and milk price: feed cost ratio influence the preferred system. All dairy systems have an environmental impact and inputs to maximise profit may lead to pollution levels unacce...

  14. Upper Basalt-Confined Aquifer System in the Southern Hanford Site

    SciTech Connect

    Thorne, P.

    1999-01-04

    The 1990 DOE Tiger Team Finding GW/CF-202 found that the hydrogeologic regime at the Hanford Site was inadequately characterized. This finding also identified the need for completing a study of the confined aquifer in the central and southern portions of the Hanford Site. The southern portion of the site is of particular interest because hydraulic-head patterns in the upper basalt-confined aquifer system indicate that groundwater from the Hanford central plateau area, where contaminants have been found in the aquifer, flows southeast toward the southern site boundary. This results in a potential for offsite migration of contaminants through the upper basalt-confined aquifer system. Based on the review presented in this report, available hydrogeologic characterization information for the upper basalt-confined aquifer system in this area is considered adequate to close the action item. Recently drilled offsite wells have provided additional information on the structure of the aquifer system in and near the southern part of the Hanford Site. Information on hydraulic properties, hydrochemistry, hydraulic heads and flow directions for the upper basalt-confined aquifer system has been re-examined and compiled in recent reports including Spane and Raymond (1993), Spane and Vermeul ( 1994), and Spane and Webber (1995).

  15. How Did a Major Confined Flare Occur in Super Solar Active Region 12192?

    NASA Astrophysics Data System (ADS)

    Jiang, Chaowei; Wu, S. T.; Yurchyshyn, Vasyl; Wang, Haiming; Feng, Xueshang; Hu, Qiang

    2016-09-01

    We study the physical mechanism of a major X-class solar flare that occurred in the super NOAA active region (AR) 12192 using data-driven numerical magnetohydrodynamic (MHD) modeling complemented with observations. With the evolving magnetic fields observed at the solar surface as bottom boundary input, we drive an MHD system to evolve self-consistently in correspondence with the realistic coronal evolution. During a two-day time interval, the modeled coronal field has been slowly stressed by the photospheric field evolution, which gradually created a large-scale coronal current sheet, i.e., a narrow layer with intense current, in the core of the AR. The current layer was successively enhanced until it became so thin that a tether-cutting reconnection between the sheared magnetic arcades was set in, which led to a flare. The modeled reconnecting field lines and their footpoints match well the observed hot flaring loops and the flare ribbons, respectively, suggesting that the model has successfully “reproduced” the macroscopic magnetic process of the flare. In particular, with simulation, we explained why this event is a confined eruption—the consequence of the reconnection is a shared arcade instead of a newly formed flux rope. We also found a much weaker magnetic implosion effect compared to many other X-class flares.

  16. Phase behaviour and correlations of parallel hard squares: from highly confined to bulk systems

    NASA Astrophysics Data System (ADS)

    González-Pinto, Miguel; Martínez-Ratón, Yuri; Varga, Szabolcs; Gurin, Peter; Velasco, Enrique

    2016-06-01

    We study a fluid of two-dimensional parallel hard squares in bulk and under confinement in channels, with the aim of evaluating the performance of fundamental-measure theory (FMT). To this purpose, we first analyse the phase behaviour of the bulk system using FMT and Percus–Yevick (PY) theory, and compare the results with molecular dynamics and Monte Carlo simulations. In a second step, we study the confined system and check the results against those obtained from the transfer matrix method and from our own Monte Carlo simulations. Squares are confined to channels with parallel walls at angles of 0° or 45° relative to the diagonals of the parallel hard squares, respectively, which allows for an assessment of the effect of the external-potential symmetry on the fluid structural properties. In general FMT overestimates bulk correlations, predicting the existence of a columnar phase (absent in simulations) prior to crystallization. The equation of state predicted by FMT compares well with simulations, although the PY approach with the virial route is better in some range of packing fractions. The FMT is highly accurate for the structure and correlations of the confined fluid due to the dimensional crossover property fulfilled by the theory. Both density profiles and equations of state of the confined system are accurately predicted by the theory. The highly non-uniform pair correlations inside the channel are also very well described by FMT.

  17. Phase behaviour and correlations of parallel hard squares: from highly confined to bulk systems.

    PubMed

    González-Pinto, Miguel; Martínez-Ratón, Yuri; Varga, Szabolcs; Gurin, Peter; Velasco, Enrique

    2016-06-22

    We study a fluid of two-dimensional parallel hard squares in bulk and under confinement in channels, with the aim of evaluating the performance of fundamental-measure theory (FMT). To this purpose, we first analyse the phase behaviour of the bulk system using FMT and Percus-Yevick (PY) theory, and compare the results with molecular dynamics and Monte Carlo simulations. In a second step, we study the confined system and check the results against those obtained from the transfer matrix method and from our own Monte Carlo simulations. Squares are confined to channels with parallel walls at angles of 0° or 45° relative to the diagonals of the parallel hard squares, respectively, which allows for an assessment of the effect of the external-potential symmetry on the fluid structural properties. In general FMT overestimates bulk correlations, predicting the existence of a columnar phase (absent in simulations) prior to crystallization. The equation of state predicted by FMT compares well with simulations, although the PY approach with the virial route is better in some range of packing fractions. The FMT is highly accurate for the structure and correlations of the confined fluid due to the dimensional crossover property fulfilled by the theory. Both density profiles and equations of state of the confined system are accurately predicted by the theory. The highly non-uniform pair correlations inside the channel are also very well described by FMT. PMID:27115832

  18. Controlling enzymatic activity and kinetics in swollen mesophases by physical nano-confinement

    NASA Astrophysics Data System (ADS)

    Sun, Wenjie; Vallooran, Jijo J.; Zabara, Alexandru; Mezzenga, Raffaele

    2014-05-01

    Bicontinuous lipid cubic mesophases are widely investigated as hosting matrices for functional enzymes to build biosensors and bio-devices due to their unique structural characteristics. However, the enzymatic activity within standard mesophases (in-meso) is severely hindered by the relatively small diameter of the mesophase aqueous channels, which provide only limited space for enzymes, and restrict them into a highly confined environment. We show that the enzymatic activity of a model enzyme, horseradish peroxidase (HRP), can be accurately controlled by relaxing its confinement within the cubic phases' water channels, when the aqueous channel diameters are systematically swollen with varying amount of hydration-enhancing sugar ester. The in-meso activity and kinetics of HRP are then systematically investigated by UV-vis spectroscopy, as a function of the size of the aqueous mesophase channels. The enzymatic activity of HRP increases with the swelling of the water channels. In swollen mesophases with water channel diameter larger than the HRP size, the enzymatic activity is more than double that measured in standard mesophases, approaching again the enzymatic activity of free HRP in bulk water. We also show that the physically-entrapped enzymes in the mesophases exhibit a restricted-diffusion-induced initial lag period and report the first observation of in-meso enzymatic kinetics significantly deviating from the normal Michaelis-Menten behaviour observed in free solutions, with deviations vanishing when enzyme confinement is released by swelling the mesophase.Bicontinuous lipid cubic mesophases are widely investigated as hosting matrices for functional enzymes to build biosensors and bio-devices due to their unique structural characteristics. However, the enzymatic activity within standard mesophases (in-meso) is severely hindered by the relatively small diameter of the mesophase aqueous channels, which provide only limited space for enzymes, and restrict them

  19. Hydrogeologic framework and geologic structure of the Floridan aquifer system and intermediate confining unit in the Lake Okeechobee area, Florida

    USGS Publications Warehouse

    Reese, Ronald S.

    2014-01-01

    The successful implementation of aquifer storage and recovery (ASR) as a water-management tool requires detailed information on the hydrologic and hydraulic properties of the potential water storage zones. This report presents stratigraphic and hydrogeologic sections of the upper part of the Floridan aquifer system and the overlying confining unit or aquifer system in the Lake Okeechobee area, and contour maps of the upper contacts of the Ocala Limestone and the Arcadia Formation, which are represented in the sections. The sections and maps illustrate hydrogeologic factors such as confinement of potential storage zones, the distribution of permeability within the zones, and geologic features that may control the efficiency of injection, storage, and recovery of water, and thus may influence decisions on ASR activities in areas of interest to the Comprehensive Everglades Restoration Plan.

  20. Determination of broken KAM surfaces for particle orbits in toroidal confinement systems

    DOE PAGESBeta

    White, R. B.

    2015-10-05

    Here, the destruction of Kolmogorov–Arnold–Moser surfaces in a Hamiltonian system is an important topic in nonlinear dynamics, and in particular in the theory of particle orbits in toroidal magnetic confinement systems. Analytic models for transport due to mode-particle resonances are not sufficiently correct to give the effect of these resonances on transport. In this paper we compare three different methods for the detection of the loss of stability of orbits in the dynamics of charged particles in a toroidal magnetic confinement device in the presence of time dependent magnetic perturbations.

  1. On the stochastic behaviors of locally confined particle systems

    SciTech Connect

    Li, Yao

    2015-07-15

    We investigate a class of Hamiltonian particle systems and their stochastic behaviors. Using both rigorous proof and numerical simulations, we show that the geometric configuration can qualitatively change key statistical characteristics of the particle system, which are expected to be retained by stochastic modifications. In particular, whether a particle system has an exponential mixing rate or a polynomial mixing rate depends on whether the geometric setting allows a slow particle being reached by adjacent fast particles.

  2. Robotic system for retractable teleoperated arm within enclosed shell with capability of operating within a confined space

    DOEpatents

    Randolph, John David; Lloyd, Peter Downes; Love, Lonnie Joe; Kwon, Dong Soo; Blank, James Allen; Davis, Hurley Thomas

    2001-01-01

    An apparatus for performing a task in a confined space having an access port. The apparatus comprise: a confinement box securable to the access port of the confined space; a shell extending from the confinement box; a teleoperated arm movable between a retracted position, in which the teleoperated arm is disposed within the shell, and a deployed position, in which the teleoperated arm extends through the access port and into the confined space to perform the task; and a control system for commanding the teleoperated arm. The arm links and joint connectors of the teleoperated arm assembly are the conduits for the process

  3. Improved confinement region without large magnetohydrodynamic activity in TPE-RX reversed-field pinch plasma

    SciTech Connect

    Yambe, Kiyoyuki; Hirano, Yoichi; Sakakita, Hajime; Koguchi, Haruhisa

    2014-11-15

    We found that spontaneous improved confinement was brought about depending on the operating region in the Toroidal Pinch Experiment-Reversed eXperiment (TPE-RX) reversed-field pinch plasma [Y. Yagi et al., Fusion Eng. Des. 45, 421 (1999)]. Gradual decay of the toroidal magnetic field at plasma surface B{sub tw} reversal makes it possible to realize a prolonged discharge, and the poloidal beta value and energy confinement time increase in the latter half of the discharge, where reversal and pinch parameters become shallow and low, respectively. In the latter half of the discharge, the plasma current and volume-averaged toroidal magnetic field 〈B{sub t}〉 increase again, the electron density slowly decays, the electron temperature and soft X-ray radiation intensity increase, and the magnetic fluctuations are markedly reduced. In this period of improved confinement, the value of (〈B{sub t}〉-B{sub tw})/B{sub pw}, where B{sub pw} is the poloidal magnetic field at the plasma surface, stays almost constant, which indicates that the dynamo action occurs without large magnetohydrodynamic activities.

  4. Improved confinement region without large magnetohydrodynamic activity in TPE-RX reversed-field pinch plasma

    NASA Astrophysics Data System (ADS)

    Yambe, Kiyoyuki; Hirano, Yoichi; Sakakita, Hajime; Koguchi, Haruhisa

    2014-11-01

    We found that spontaneous improved confinement was brought about depending on the operating region in the Toroidal Pinch Experiment-Reversed eXperiment (TPE-RX) reversed-field pinch plasma [Y. Yagi et al., Fusion Eng. Des. 45, 421 (1999)]. Gradual decay of the toroidal magnetic field at plasma surface Btw reversal makes it possible to realize a prolonged discharge, and the poloidal beta value and energy confinement time increase in the latter half of the discharge, where reversal and pinch parameters become shallow and low, respectively. In the latter half of the discharge, the plasma current and volume-averaged toroidal magnetic field increase again, the electron density slowly decays, the electron temperature and soft X-ray radiation intensity increase, and the magnetic fluctuations are markedly reduced. In this period of improved confinement, the value of (-Btw)/Bpw, where Bpw is the poloidal magnetic field at the plasma surface, stays almost constant, which indicates that the dynamo action occurs without large magnetohydrodynamic activities.

  5. New systems for treatment of manure from confined animal production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New swine waste management systems developed in North Carolina to replace the anaerobic lagoons need to meet the strict performance standards of an environmentally superior technology (EST). These technologies must be able to substantially remove nutrients, heavy metals, emissions of ammonia, odors,...

  6. SAFIRE: A systems analysis code for ICF (inertial confinement fusion) reactor economics

    SciTech Connect

    McCarville, T.J.; Meier, W.R.; Carson, C.F.; Glasgow, B.B.

    1987-01-12

    The SAFIRE (Systems Analysis for ICF Reactor Economics) code incorporates analytical models for scaling the cost and performance of several inertial confinement fusion reactor concepts for electric power. The code allows us to vary design parameters (e.g., driver energy, chamber pulse rate, net electric power) and evaluate the resulting change in capital cost of power plant and the busbar cost of electricity. The SAFIRE code can be used to identify the most attractive operating space and to identify those design parameters with the greatest leverage for improving the economics of inertial confinement fusion electric power plants.

  7. Analysis of Confined Random Walkers with Applications to Processes Occurring in Molecular Aggregates and Immunological Systems.

    PubMed

    Chase, Matthew; Spendier, Kathrin; Kenkre, V M

    2016-03-31

    Explicit solutions are presented in the Laplace and time domains for a one-variable Fokker-Planck equation governing the probability density of a random walker moving in a confining potential. Illustrative applications are discussed in two unrelated physical contexts: quantum yields in a doped molecular crystal or photosynthetic system, and the motion of signal receptor clusters on the surface of a cell encountered in a problem in immunology. An interesting counterintuitive effect concerning the consequences of confinement is found in the former, and some insights into the driving force for microcluster centralization are gathered in the latter application. PMID:26885727

  8. Program status 3. quarter -- FY 1990: Confinement systems programs

    SciTech Connect

    1990-07-24

    Highlights of the DIII-D Research Operations task are: completed five weeks tokamak operations; initiated summer vent; achievement of 10.7% beta; carried out first dimensionless transport scaling experiment; completed IBW program; demonstrated divertor heat reduction with gas puffing; field task proposals presented to OFE; presentation of DIII-D program to FPAC; made presentation to Admiral Watkins; and SAN safety review. Summaries are given on research programs, operations, program development, hardware development, operations support and collaborative efforts. Brief summaries of progress on the International Cooperation task include: TORE SUPRA, ASDEX, JFT-2M, and JET. Funding for work on CIT physics was received this quarter. Several physics R and D planning tasks were initiated. Earlier in FY90, a poloidal field coil shaping system (PFC) was found for DIGNITOR. This quarter more detailed analysis has been done to optimize the design of the PFC system.

  9. Liver lipid content of twenty varieties of laying hens from three confinement systems.

    PubMed

    Garlich, J D; Olson, J D; Huff, W E; Hamilton, P B

    1975-05-01

    Average liver lipid values were determined for 20 varieties of 71-week old laying hens managed in 3 confinement systems of the 1972-73 North Carolina Random Sample Laying Test. There were highly significant differences in liver lipid atrributable to variety, to confinement system, and a significant variety X system interaction. Four varieties had consistently high and five had consistently low liver lipid values in all 3 confinement systems. Varietymeans ranged from 25.8 to 49.0% liver lipid on a dry weight basis. Hens confined 2/cage had slight but significantly higher liver lipid than hens 7/cage or in floor pens. Liver lipid was positively correlated with body weight in hens 2/cage and in floor pens. There were no significant correlations of liver lipid with egg production or mortality. A frequency distribution of individual liver lipid values revealed a continuous distribution from 15.4 to 65.4with a pronounced skew to the right of the mean of 38.2%. Neither a fatty liver syndrome nor liver hemorrhage syndrome was reported for any of the flocks during the laying year. The normal range of liver lipid values for hens 71 weeks of age appears to be between 25 and 49 g. of lipid per 100 g. of dry liver weight. PMID:1153379

  10. Nanoionics: ion transport and electrochemical storage in confined systems.

    PubMed

    Maier, J

    2005-11-01

    The past two decades have shown that the exploration of properties on the nanoscale can lead to substantially new insights regarding fundamental issues, but also to novel technological perspectives. Simultaneously it became so fashionable to decorate activities with the prefix 'nano' that it has become devalued through overuse. Regardless of fashion and prejudice, this article shows that the crystallizing field of 'nanoionics' bears the conceptual and technological potential that justifies comparison with the well-acknowledged area of nanoelectronics. Demonstrating this potential implies both emphasizing the indispensability of electrochemical devices that rely on ion transport and complement the world of electronics, and working out the drastic impact of interfaces and size effects on mass transfer, transport and storage. The benefits for technology are expected to lie essentially in the field of room-temperature devices, and in particular in artificial self-sustaining structures to which both nanoelectronics and nanoionics might contribute synergistically. PMID:16379070

  11. Cooperation of different exchange mechanisms in confined magnetic systems

    NASA Astrophysics Data System (ADS)

    Schwabe, Andrej; Hänsel, Mirek; Potthoff, Michael

    2014-09-01

    The diluted Kondo lattice model is investigated at strong antiferromagnetic local exchange couplings J, where almost-local Kondo clouds drastically restrict the motion of conduction electrons, giving rise to the possibility of quantum localization of conduction electrons for certain geometries of impurity spins. This localization may lead to the formation of local magnetic moments in the conduction-electron system, and the inverse indirect magnetic exchange (IIME) provided by virtual excitations of the Kondo singlets couples those local moments to the remaining electrons. Exemplarily, we study the one-dimensional two-impurity Kondo model with impurity spins near the chain ends, which supports the formation of conduction-electron magnetic moments at the edges of the chain for sufficiently strong J. Employing degenerate perturbation theory as well as analyzing spin gaps numerically by means of the density-matrix renormalization group, it is shown that the low-energy physics of the model can be well captured within an effective antiferromagnetic Ruderman-Kittel-Kasuya-Yosida-like two-spin model ("RKKY from IIME") or within an effective central-spin model, depending on edge-spin distance and system size.

  12. Program status 3. quarter -- FY 1994: Confinement systems programs

    SciTech Connect

    1994-07-19

    Highlights of the DIII-D Research Operations are: began experimental research operations; successfully passed radiative divertor project review; presented papers at PSI, Diagnostics, and EPS meetings and prepared IAEA synopses; new computer speeds up data acquisition; completed installation of FWCD antennas with Faraday shields; and completed report of radiative divertor preliminary design with review committee. Summaries are given for progress in research programs; operations; mechanical engineering; electrical engineering; upgrade project; operations support; and collaborative efforts. Brief summaries are given for progress on the International Cooperation task which include JET, ASDEX, TEXTOR, TORE SUPRA, JAERI, TRINTI, T-10, and ARIES support. The work in support of the development plan for the TPX (Tokamak Physics Experiment) goals and milestones continued. Progress in improving on existing models and codes leading to improved understanding of experiments is given. Highlights from the User Service Center are: 18 gigabytes of disks were purchased for exclusive fusion use; a Hewlett-Packard 9000 Series 800 T500 computer was selected as the fusion complete server; the first VAX was removed from the USC cluster; security vulnerability on HP VUE software was corrected; and a cleanup script was developed for the NERSC Cray system. A list of personnel and their assignments is given for the ITER Design Engineering task.

  13. An interpolatory ansatz captures the physics of one-dimensional confined Fermi systems

    PubMed Central

    Andersen, M. E. S.; Dehkharghani, A. S.; Volosniev, A. G.; Lindgren, E. J.; Zinner, N. T.

    2016-01-01

    Interacting one-dimensional quantum systems play a pivotal role in physics. Exact solutions can be obtained for the homogeneous case using the Bethe ansatz and bosonisation techniques. However, these approaches are not applicable when external confinement is present. Recent theoretical advances beyond the Bethe ansatz and bosonisation allow us to predict the behaviour of one-dimensional confined systems with strong short-range interactions, and new experiments with cold atomic Fermi gases have already confirmed these theories. Here we demonstrate that a simple linear combination of the strongly interacting solution with the well-known solution in the limit of vanishing interactions provides a simple and accurate description of the system for all values of the interaction strength. This indicates that one can indeed capture the physics of confined one-dimensional systems by knowledge of the limits using wave functions that are much easier to handle than the output of typical numerical approaches. We demonstrate our scheme for experimentally relevant systems with up to six particles. Moreover, we show that our method works also in the case of mixed systems of particles with different masses. This is an important feature because these systems are known to be non-integrable and thus not solvable by the Bethe ansatz technique. PMID:27324113

  14. An interpolatory ansatz captures the physics of one-dimensional confined Fermi systems.

    PubMed

    Andersen, M E S; Dehkharghani, A S; Volosniev, A G; Lindgren, E J; Zinner, N T

    2016-01-01

    Interacting one-dimensional quantum systems play a pivotal role in physics. Exact solutions can be obtained for the homogeneous case using the Bethe ansatz and bosonisation techniques. However, these approaches are not applicable when external confinement is present. Recent theoretical advances beyond the Bethe ansatz and bosonisation allow us to predict the behaviour of one-dimensional confined systems with strong short-range interactions, and new experiments with cold atomic Fermi gases have already confirmed these theories. Here we demonstrate that a simple linear combination of the strongly interacting solution with the well-known solution in the limit of vanishing interactions provides a simple and accurate description of the system for all values of the interaction strength. This indicates that one can indeed capture the physics of confined one-dimensional systems by knowledge of the limits using wave functions that are much easier to handle than the output of typical numerical approaches. We demonstrate our scheme for experimentally relevant systems with up to six particles. Moreover, we show that our method works also in the case of mixed systems of particles with different masses. This is an important feature because these systems are known to be non-integrable and thus not solvable by the Bethe ansatz technique. PMID:27324113

  15. An interpolatory ansatz captures the physics of one-dimensional confined Fermi systems

    NASA Astrophysics Data System (ADS)

    Andersen, M. E. S.; Dehkharghani, A. S.; Volosniev, A. G.; Lindgren, E. J.; Zinner, N. T.

    2016-06-01

    Interacting one-dimensional quantum systems play a pivotal role in physics. Exact solutions can be obtained for the homogeneous case using the Bethe ansatz and bosonisation techniques. However, these approaches are not applicable when external confinement is present. Recent theoretical advances beyond the Bethe ansatz and bosonisation allow us to predict the behaviour of one-dimensional confined systems with strong short-range interactions, and new experiments with cold atomic Fermi gases have already confirmed these theories. Here we demonstrate that a simple linear combination of the strongly interacting solution with the well-known solution in the limit of vanishing interactions provides a simple and accurate description of the system for all values of the interaction strength. This indicates that one can indeed capture the physics of confined one-dimensional systems by knowledge of the limits using wave functions that are much easier to handle than the output of typical numerical approaches. We demonstrate our scheme for experimentally relevant systems with up to six particles. Moreover, we show that our method works also in the case of mixed systems of particles with different masses. This is an important feature because these systems are known to be non-integrable and thus not solvable by the Bethe ansatz technique.

  16. System and method for generating steady state confining current for a toroidal plasma fusion reactor

    DOEpatents

    Fisch, Nathaniel J.

    1981-01-01

    A system for generating steady state confining current for a toroidal plasma fusion reactor providing steady-state generation of the thermonuclear power. A dense, hot toroidal plasma is initially prepared with a confining magnetic field with toroidal and poloidal components. Continuous wave RF energy is injected into said plasma to establish a spectrum of traveling waves in the plasma, where the traveling waves have momentum components substantially either all parallel, or all anti-parallel to the confining magnetic field. The injected RF energy is phased to couple to said traveling waves with both a phase velocity component and a wave momentum component in the direction of the plasma traveling wave components. The injected RF energy has a predetermined spectrum selected so that said traveling waves couple to plasma electrons having velocities in a predetermined range .DELTA.. The velocities in the range are substantially greater than the thermal electron velocity of the plasma. In addition, the range is sufficiently broad to produce a raised plateau having width .DELTA. in the plasma electron velocity distribution so that the plateau electrons provide steady-state current to generate a poloidal magnetic field component sufficient for confining the plasma. In steady state operation of the fusion reactor, the fusion power density in the plasma exceeds the power dissipated in the plasma.

  17. System and method for generating steady state confining current for a toroidal plasma fusion reactor

    DOEpatents

    Bers, Abraham

    1981-01-01

    A system for generating steady state confining current for a toroidal plasma fusion reactor providing steady-state generation of the thermonuclear power. A dense, hot toroidal plasma is initially prepared with a confining magnetic field with toroidal and poloidal components. Continuous wave RF energy is injected into said plasma to estalish a spectrum of traveling waves in the plasma, where the traveling waves have momentum components substantially either all parallel, or all anti-parallel to the confining magnetic field. The injected RF energy is phased to couple to said traveling waves with both a phase velocity component and a wave momentum component in the direction of the plasma traveling wave components. The injected RF energy has a predetermined spectrum selected so that said traveling waves couple to plasma electrons having velocities in a predetermined range .DELTA.. The velocities in the range are substantially greater than the thermal electron velocity of the plasma. In addition, the range is sufficiently broad to produce a raised plateau having width .DELTA. in the plasma electron velocity distribution so that the plateau electrons provide steady-state current to generate a poloidal magnetic field component sufficient for confining the plasma. In steady state operation of the fusion reactor, the fusion power density in the plasma exceeds the power dissipated inthe plasma.

  18. Nickel Confined in the Interlayer Region of Birnessite: an Active Electrocatalyst for Water Oxidation.

    PubMed

    Thenuwara, Akila C; Cerkez, Elizabeth B; Shumlas, Samantha L; Attanayake, Nuwan H; McKendry, Ian G; Frazer, Laszlo; Borguet, Eric; Kang, Qing; Remsing, Richard C; Klein, Michael L; Zdilla, Michael J; Strongin, Daniel R

    2016-08-22

    We report a synthetic method to enhance the electrocatalytic activity of birnessite for the oxygen evolution reaction (OER) by intercalating Ni(2+) ions into the interlayer region. Electrocatalytic studies showed that nickel (7.7 atomic %)-intercalated birnessite exhibits an overpotential (η) of 400 mV for OER at an anodic current of 10 mA cm(-2) . This η is significantly lower than the η values for birnessite (η≈700 mV) and the active OER catalyst β-Ni(OH)2 (η≈550 mV). Molecular dynamics simulations suggest that a competition among the interactions between the nickel cation, water, and birnessite promote redox chemistry in the spatially confined interlayer region. PMID:27151204

  19. Influence of the interface on the optical activity of confined glucose films.

    PubMed

    Emile, Olivier; Emile, Janine; Ghoufi, Aziz

    2016-09-01

    We report on the time evolution of the optical activity of a thinning liquid film containing glucose, and confined between two glass slides. This dynamics strongly depends on the presence of surfactant molecules. With sodium dodecyl sulfate (SDS), we evidence favorable interactions of sugar molecules with the sulfate group. As previously observed for a freely suspended soap film in the air (see Emile et al., 2013), this corresponds to an anchoring of glucose molecules at the interface. For glucose alone, we also highlight a molecular rearrangement that is not instantaneous and occurs after several minutes. This interfacial organization leads to an unusual giant optical activity that is different with or without SDS. Molecular simulations confirm the anchoring of the glucose molecules at the glass/liquid interface, and show a different molecular orientation in each case. PMID:27254252

  20. Multiple Steps to Activate FAK’s Kinase Domain: Adaptation to Confined Environments?

    PubMed Central

    Herzog, Florian A.; Vogel, Viola

    2013-01-01

    Protein kinases regulate cell signaling by phosphorylating their substrates in response to environment-specific stimuli. Using molecular dynamics, we studied the catalytically active and inactive conformations of the kinase domain of the focal adhesion kinase (FAK), which are distinguished by displaying a structured or unstructured activation loop, respectively. Upon removal of an ATP analog, we show that the nucleotide-binding pocket in the catalytically active conformation is structurally unstable and fluctuates between an open and closed configuration. In contrast, the pocket remains open in the catalytically inactive form upon removal of an inhibitor from the pocket. Because temporal pocket closures will slow the ATP on-rate, these simulations suggest a multistep process in which the kinase domain is more likely to bind ATP in the catalytically inactive than in the active form. Transient closures of the ATP-binding pocket might allow FAK to slow down its catalytic cycle. These short cat naps could be adaptions to crowded or confined environments by giving the substrate sufficient time to diffuse away. The simulations show further how either the phosphorylation of the activation loop or the activating mutations of the so-called SuperFAK influence the electrostatic switch that controls kinase activity. PMID:23746525

  1. Surface-confined activation of ultra low-k dielectrics in CO2 plasma

    NASA Astrophysics Data System (ADS)

    Sun, Yiting; Krishtab, Mikhail; Mankelevich, Yuri; Zhang, Liping; De Feyter, Steven; Baklanov, Mikhail; Armini, Silvia

    2016-06-01

    An approach allowing surface-confined activation of porous organosilicate based low-k dielectrics is proposed and studied. By examining the plasma damage mechanism of low-k, we came up with an initial idea that the main requirements for the surface-confined modification would be the high reactivity and high recombination rate of the plasma species. Based on this concept, CO2 plasma was selected and benchmarked with several other plasmas. It is demonstrated that a short exposure of organosilicate low-k films to CO2 plasma enables high surface hydrophilicity with limited bulk modification. CO2+ ions predominantly formed in this plasma have high oxidation potential and efficiently remove surface -CH3 groups from low-k. At the same time, the CO2+ ions get easily discharged (deactivated) during their collisions with pore walls and therefore have very limited probability of penetration into the low-k bulk. Low concentration of oxygen radicals is another factor avoiding the bulk damage. The chemical reactions describing the interactions between CO2 plasma and low-k dielectrics are proposed.

  2. Convective plasma stability consistent with MHD equilibrium in magnetic confinement systems with a decreasing field

    SciTech Connect

    Tsventoukh, M. M.

    2010-10-15

    A study is made of the convective (interchange, or flute) plasma stability consistent with equilibrium in magnetic confinement systems with a magnetic field decreasing outward and large curvature of magnetic field lines. Algorithms are developed which calculate convective plasma stability from the Kruskal-Oberman kinetic criterion and in which the convective stability is iteratively consistent with MHD equilibrium for a given pressure and a given type of anisotropy in actual magnetic geometry. Vacuum and equilibrium convectively stable configurations in systems with a decreasing, highly curved magnetic field are calculated. It is shown that, in convectively stable equilibrium, the possibility of achieving high plasma pressures in the central region is restricted either by the expansion of the separatrix (when there are large regions of a weak magnetic field) or by the filamentation of the gradient plasma current (when there are small regions of a weak magnetic field, in which case the pressure drops mainly near the separatrix). It is found that, from the standpoint of equilibrium and of the onset of nonpotential ballooning modes, a kinetic description of convective stability yields better plasma confinement parameters in systems with a decreasing, highly curved magnetic field than a simpler MHD model and makes it possible to substantially improve the confinement parameters for a given type of anisotropy. For the Magnetor experimental compact device, the maximum central pressure consistent with equilibrium and stability is calculated to be as high as {beta} {approx} 30%. It is shown that, for the anisotropy of the distribution function that is typical of a background ECR plasma, the limiting pressure gradient is about two times steeper than that for an isotropic plasma. From a practical point of view, the possibility is demonstrated of achieving better confinement parameters of a hot collisionless plasma in systems with a decreasing, highly curved magnetic field

  3. The Effect of Nano Confinement on the C–H Activation and its Corresponding Structure-Activity Relationship

    PubMed Central

    Shao, Jing; Yuan, Linghua; Hu, Xingbang; Wu, Youting; Zhang, Zhibing

    2014-01-01

    The C–H activation of methane, ethane, and t-butane on inner and outer surfaces of nitrogen-doped carbon nanotube (NCNTs) are investigated using density functional theory. It includes NCNTs with different diameters, different N and O concentrations, and different types (armchair and zigzag). A universal structure-reactivity relationship is proposed to characterize the C–H activation occurring both on the inner and outer surfaces of the nano channel. The C–O bond distance, spin density and charge carried by active oxygen are found to be highly related to the C–H activation barriers. Based on these theoretical results, some useful strategies are suggested to guide the rational design of more effective catalysts by nano channel confinement. PMID:25428459

  4. The Effect of Nano Confinement on the C-H Activation and its Corresponding Structure-Activity Relationship

    NASA Astrophysics Data System (ADS)

    Shao, Jing; Yuan, Linghua; Hu, Xingbang; Wu, Youting; Zhang, Zhibing

    2014-11-01

    The C-H activation of methane, ethane, and t-butane on inner and outer surfaces of nitrogen-doped carbon nanotube (NCNTs) are investigated using density functional theory. It includes NCNTs with different diameters, different N and O concentrations, and different types (armchair and zigzag). A universal structure-reactivity relationship is proposed to characterize the C-H activation occurring both on the inner and outer surfaces of the nano channel. The C-O bond distance, spin density and charge carried by active oxygen are found to be highly related to the C-H activation barriers. Based on these theoretical results, some useful strategies are suggested to guide the rational design of more effective catalysts by nano channel confinement.

  5. Experimental Modeling of a Novel Magnetic Confinement System: Galathea with a Myxine in the Shape of a Convex Polyhedron

    SciTech Connect

    Gordienko, V.A.; Dubinov, A.E.; Zhuravlev, S.S.; Ivanov, M.M.; Repin, P.B.

    2005-03-15

    A new type of magnetic confinement system--a Galathea with a myxine in the shape of a convex polyhedron--is proposed. The system was modeled experimentally by passing an RF current through the myxine. On the one hand, the myxine acts as an inductor whose electric field ionizes the gas and, on the other, it acts as an RF magnetic confinement system. A steady-state plasma produced and confined in this system is almost spherical in shape. The electron density and specific (per unit volume) glow intensity of the plasma produced are found to be higher than those in conventional helical inductors.

  6. Confined cooperative self-assembly and synthesis of optically and electrically active nanostructures : final LDRD report

    SciTech Connect

    Coker, Eric Nicholas; Haddad, Raid Edward; Fan, Hongyou; Ta, Anh; Bai, Feng; Rodriguez, Mark Andrew; Huang, Jian Yu

    2011-10-01

    In this project, we developed a confined cooperative self-assembly process to synthesize one-dimensional (1D) j-aggregates including nanowires and nanorods with controlled diameters and aspect ratios. The facile and versatile aqueous solution process assimilates photo-active macrocyclic building blocks inside surfactant micelles, forming stable single-crystalline high surface area nanoporous frameworks with well-defined external morphology defined by the building block packing. Characterizations using TEM, SEM, XRD, N{sub 2} and NO sorption isotherms, TGA, UV-vis spectroscopy, and fluorescence imaging and spectroscopy indicate that the j-aggregate nanostructures are monodisperse and may further assemble into hierarchical arrays with multi-modal functional pores. The nanostructures exhibit enhanced and collective optical properties over the individual chromophores. This project was a small footprint research effort which, nonetheless, produced significant progress towards both the stated goal as well as unanticipated research directions.

  7. Safety management for polluted confined space with IT system: a running case

    PubMed Central

    Hwang, Jing-Jang; Wu, Chien-Hsing; Zhuang, Zheng-Yun; Hsu, Yi-Chang

    2015-01-01

    This study traced a deployed real IT system to enhance occupational safety for a polluted confined space. By incorporating wireless technology, it automatically monitors the status of workers on the site and upon detected anomalous events, managers are notified effectively. The system, with a redefined standard operations process, is running well at one of Formosa Petrochemical Corporation's refineries. Evidence shows that after deployment, the system does enhance the safety level by real-time monitoring the workers and by managing well and controlling the anomalies. Therefore, such technical architecture can be applied to similar scenarios for safety enhancement purposes. PMID:26323784

  8. Confinement effects upon the separation of structural transitions in linear systems with restricted bond fluctuation ranges.

    PubMed

    Koci, Tomas; Bachmann, Michael

    2015-10-01

    By means of advanced parallel replica-exchange Monte Carlo methods we examine the influence of elasticity and confinement on the structural transitions of linear systems with restricted bonded interaction. For this purpose, we adopt a model for coarse-grained flexible polymers of finite length in the dilute regime. Hyperphase diagrams are constructed using energy-dependent canonical quantities to demonstrate the effects of the changes in the range of the confined interaction on the liquid and solid structural phases. With increasing bonded interaction range we observe the disappearance of the liquid phase and the fusion of the gas-liquid (or Θ) and the liquid-solid transitions. One of the most remarkable features, the liquid-gas transition, changes from second to first order if the confined interaction range exceeds a threshold that separates polymeric from nonpolymeric systems. The notoriously difficult sampling of the entropically suppressed conformations in the region of very strong first-order transitions is improved by using multiple Gaussian modified ensembles. PMID:26565203

  9. Near infrared emission from molecule-like silver clusters confined in zeolite A assisted by thermal activation

    SciTech Connect

    Lin, Hui Imakita, Kenji; Rong Gui, Sa Chu; Fujii, Minoru

    2014-07-07

    Strong and broad near infrared (NIR) emission peaked at ~855 nm upon optimal excitation at 342 nm has been observed from molecule-like silver clusters (MLSCs) confined in zeolite A assisted by thermal activation. To the best of our knowledge, this is the first observation of NIR emission peaked at longer than 800 nm from MLSCs confined in solid matrices. The decay time of the NIR emission is over 10 μs, which indicates that it is a spin-forbidden transition. The ~855 nm NIR emission shows strong dependence on the silver loading concentration and the thermal activation temperature.

  10. Carbon Single-Wall Nanatube Growth in a Volumetrically Confined Arc Discharge System

    SciTech Connect

    Franz, K.J.; Alleman, J.L.; Jones, K.M.; Dillon, A.C.; Heben, M.J.

    2004-01-01

    Carbon nanotubes hold significant promise for a vast number of materials applications due to their unique mechanical, electrical, and gas storage properties. Although carbon single-wall nanotubes (SWNTs) have been synthesized since 1993 by the arc discharge method, and numerous other synthesis methods have since been developed, no method has yet produced 100% pure carbon nanotubes. Instead, a significant amount of impurities—various carbon structures and metal catalysts—are present in the raw soot. While arc discharge was the first method for SWNT synthesis, it also produces more impure raw soot in comparison to the more recently developed laser vaporization, which has produced the purest raw soot to date but is much slower. Geometry and thermal gradient are appreciably different between traditional arc discharge systems and laser vaporization systems. We report that, by incorporating some characteristics inherent to a laser vaporization system into an arc discharge system, improvement in the yield of SWNT raw soot may be achieved. This is accomplished by confining the arc within a 50 mm diameter quartz tube, similar to laser vaporization. We find through transmission electron microscopy and Raman spectroscopy that SWNTs are made in significant numbers in this confined arc discharge system, comparable to laser vaporization synthesized material. Further study is, however, required to prove reproducibility and attain an exact value for the purity of the produced raw soot.

  11. Bias activated dielectric response of excitons and excitonic Mott transition in quantum confined lasers structures.

    NASA Astrophysics Data System (ADS)

    Bhunia, Amit; Bansal, Kanika; Datta, Shouvik; Alshammari, Marzook S.; Henini, Mohamed

    In contrast to the widely reported optical techniques, there are hardly any investigations on corresponding electrical signatures of condensed matter physics of excitonic phenomena. We studied small signal steady state capacitance response in III-V materials based multi quantum well (AlGaInP) and MBE grown quantum dot (InGaAs) laser diodes to identify signatures of excitonic presence. Conductance activation by forward bias was probed using frequency dependent differential capacitance response (fdC/df), which changes characteristically with the onset of light emission indicating the occurrence of negative activation energy. Our analysis shows that it is connected with a steady state population of exciton like bound states. Calculated average energy of this bound state matches well with the binding energy of weakly confined excitons in this type of structures. Further increase in charge injection decreases the differential capacitive response in AlGaInP based diodes, indicating a gradual Mott transition of excitonic states into electron hole plasma. This electrical description of excitonic Mott transition is fully supplemented by standard optical spectroscopic signatures of band gap renormalization and phase space filling effects.

  12. 77 FR 49277 - Takes of Marine Mammals During Specified Activities; Confined Blasting Operations by the U.S...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-15

    ... blasting activities and associated potential impacts. Drill holes are small in diameter (typically 2 to 4...) take small numbers of marine mammals, by Level B harassment, incidental to confined blasting operations... allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals of...

  13. Analyzing refractive index profiles of confined fluids by interferometry part II: Multilayer and asymmetric systems.

    PubMed

    Kienle, Daniel F; Kuhl, Tonya L

    2016-09-14

    Methods for determining the substrate properties and the optical thickness of thin films or any variation in the refractive index of a fluid or film near a surface for unknown 5-layer symmetric and 3-layer asymmetric interferometers are presented. Both systems can be fully resolved without any known layer properties and without contact or confining the films. The method was tested using realistic simulated interferometer data, and was found to consistently yield accurate values for all desired properties. The method was experimentally validated through analysis of an asymmetric three layer interferometer system of linear polyethyleneimine (LPEI) adsorbed onto mica substrates of differing thickness and identical refractive index. The results were in excellent agreement with the dry polymer film properties measured using conventional SFA contact measurements. More complicated systems were also evaluated for feasibility, and any additional parameter specifications required for analysis were determined. The utility of this method is broad, as a single experiment in a laboratory setting can independently provide non-contact film properties and the effects of confinement on the film structure, which can be correlated to a simultaneously measured interaction force profile. PMID:27566361

  14. Low beta equilibrium and stability for anisotropic pressure closed field line plasma confinement systems

    SciTech Connect

    Pastukhov, V.P.; Ilgisonis, V.I.; Subbotin, A.A.

    1994-05-01

    General formalism is developed to analyze the equilibrium and stability of low beta anisotropic pressure plasmas confined in closed field line magnetic systems. The formalism allows one to consider rather general magnetic systems with nonuniform axis curvature and longitudinal profiles of toroidal and multipole poloidal field. It also allows having a strong pressure anisotropy corresponding to enhanced plasma pressure in mirror cells of the system. As an example of such a system the authors consider the recently proposed linked mirror neutron source (LMNS). Application of the above formalism to the LMNS analysis confirms most of the preliminary results, however, they obtain a considerable reduction of mirror cell axis curvature and an appreciable ellipticity of plasma cross-section in the mirror cell midplane. They have also optimized the longitudinal pressure and magnetic field distribution.

  15. Global confinement and discrete dynamo activity in the MST reversed field pinch

    SciTech Connect

    Hokin, S.; Almagri, A.; Assadi, S.; Beckstead, J.; Chartas, G.; Crocker, N.; Cudzinovic, M.; Den Hartog, D.; Dexter, R.; Holly, D.; Prager, S.; Rempel, T.; Sarff, J.; Scime, E.; Shen, W.; Spragins, C.; Sprott, C.; Starr, G.; Stoneking, M.; Watts, C. ); Nebel, R. )

    1991-04-01

    Results obtained on the Madison Symmetric Torus (MST) reversed field pinch after installation of the design poloidal field winding are presented. Values of {beta}{sub {theta}e0} {triple bond} 2{mu}{sub 0}n{sub e0}T{sub e0}/B{sub {theta}}{sup 2}(a) {approximately} 12% are achieved in low-current (I = 220 kA) operation; here n{sub e0} and T{sub e0} are central electron density and temperature, and B{sub {theta}}(a) is the poloidal magnetic field at the plasma edge. An observed decrease in {beta}{sub {theta}e0} with increasing plasma current may be due to inadequate fueling, enhanced wall interaction, and the growth of a radial field error at the vertical cut in the shell at high current. Energy confinement time varies little with plasma current, lying in the range 0.5 {minus} 1.0 ms. Strong discrete dynamo activity is present, characterized by the coupling of m = 1, n = 5 {minus} 7 modes leading to an m = 0, n = 0 crash (m and n are poloidal and toroidal mode numbers). The m = 0 crash generates toroidal flux and produces a small (2.5%) increase in plasma current. 25 refs., 9 figs., 1 tab.

  16. Radiation pressure confinement - II. Application to the broad-line region in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Baskin, Alexei; Laor, Ari; Stern, Jonathan

    2014-02-01

    Active galactic nuclei (AGN) are characterized by similar broad emission lines properties at all luminosities (1039 - 1047 erg s-1). What produces this similarity over a vast range of 108 in luminosity? Photoionization is inevitably associated with momentum transfer to the photoionized gas. Yet, most of the photoionized gas in the broad-line region (BLR) follows Keplerian orbits, which suggests that the BLR originates from gas with a large enough column for gravity to dominate. The photoionized surface layer of the gas must develop a pressure gradient due to the incident radiation force. We present solutions for the structure of such a hydrostatic photoionized gas layer in the BLR. The gas is stratified, with a low-density highly ionized surface layer, a density rise inwards and a uniform-density cooler inner region, where the gas pressure reaches the incident radiation pressure. This radiation pressure confinement (RPC) of the photoionized layer leads to a universal ionization parameter U ˜ 0.1 in the inner photoionized layer, independent of luminosity and distance. Thus, RPC appears to explain the universality of the BLR properties in AGN. We present predictions for the BLR emission per unit covering factor, as a function of distance from the ionizing source, for a range of ionizing continuum slopes and gas metallicity. The predicted mean strength of most lines (excluding H β), and their different average-emission radii, are consistent with available observations.

  17. Nonlinear dynamics of confined liquid systems with interfaces subject to forced vibrations.

    PubMed

    Higuera, María; Porter, Jeff; Varas, Fernando; Vega, José M

    2014-04-01

    A review is presented of the dynamic behavior of confined fluid systems with interfaces under monochromatic mechanical forcing, emphasizing the associated spatio-temporal structure of the fluid response. At low viscosity, vibrations significantly affect dynamics and always produce viscous mean flows, which are coupled to the primary oscillating flow and evolve on a very slow timescale. Thus, unlike the primary oscillating flow, mean flows may easily interact with the surface rheology, which generates dynamics that usually exhibit a much slower timescale than that of typical gravity-capillary waves. The review is made with an eye to the typical experimental devices used to measure surface properties, which usually consist of periodically forced, symmetric fluid systems with interfaces. The current theoretical description of these systems ignores the fluid mechanics, which could play a larger role than presently assumed. PMID:24315015

  18. Mesoscopic nucleation theory for confined systems: a one-parameter model.

    PubMed

    Durán-Olivencia, Miguel A; Lutsko, James F

    2015-02-01

    Classical nucleation theory has been recently reformulated based on fluctuating hydrodynamics [J. F. Lutsko and M. A. Durán-Olivencia, Classical nucleation theory from a dynamical approach to nucleation, J. Chem. Phys. 138, 244908 (2013). The present work extends this effort to the case of nucleation in confined systems such as small pores and vesicles. The finite available mass imposes a maximal supercritical cluster size and prohibits nucleation altogether if the system is too small. We quantity the effect of system size on the nucleation rate. We also discuss the effect of relaxing the capillary-model assumption of zero interfacial width resulting in significant changes in the nucleation barrier and nucleation rate. PMID:25768513

  19. Density distribution of a rotating plasma in Tornado magnetic confinement systems

    SciTech Connect

    Kuznetsov, V.M.; Pakhomov, A.B.; Rusakov, A.I.

    1984-12-01

    The density distribution of a rotating plasma in a Tornado magnetic confinement system is calculated under the assumption that the plasma rotates at constant angular velocity throughout the region bounded by the separatrix. The component of the centrifugal inertial force parallel to the magnetic force lines is shown to pinch the plasma toward the equatorial plane of the system. The density distribution depends on the ratio v/T of the plasma drift velocity and temperature. The experimentally measured density distribution can be used to determine v/T and thus to analyze the rotating plasma. If v is known for the rotating plasma then T can be calculated from v, and vice versa.

  20. Fabrication of Isolated Metal-Organic Polyhedra in Confined Cavities: Adsorbents/Catalysts with Unusual Dispersity and Activity.

    PubMed

    Kang, Ying-Hu; Liu, Xiao-Dan; Yan, Ni; Jiang, Yao; Liu, Xiao-Qin; Sun, Lin-Bing; Li, Jian-Rong

    2016-05-18

    Metal-organic polyhedra (MOPs) have attracted great attention due to their intriguing structure. However, the applications of MOPs are severely hindered by two shortcomings, namely low dispersity and poor stability. Here we report the introduction of four MOPs (constructed from dicopper and carboxylates) to cavity-structured mesoporous silica SBA-16 via a double-solvent strategy to overcome both shortcomings simultaneously. By judicious design, the dimension of MOPs is just between the size of cavities and entrances of SBA-16, MOP molecules are thus confined in the cavities. This leads to the formation of isolated MOPs with unusual dispersion, making the active sites highly accessible. Hence, the adsorption capacity on carbon dioxide and propene as well as catalytic performance on ring opening are much superior to bulk MOPs. More importantly, the structure and catalytic activity of MOPs in confined cavities are well preserved after exposure to humid atmosphere, whereas those of bulk MOPs are degraded seriously. PMID:27049737

  1. Enhanced Quantum Confined Stark Effect in a mesoporous hybrid multifunctional system

    NASA Astrophysics Data System (ADS)

    Gogoi, M.; Deb, P.; Sen, D.; Mazumder, S.; Kostka, A.

    2014-06-01

    Quantum Confined Stark Effect in hybrid of CdTe quantum dot with superparamagnetic iron oxide nanoparticles in both nonporous and mesoporous silica matrix has been realized. The observed QCSE is due to the local electric field induced by charge dispersion at SiO2/polar solvent interface. Enhanced Stark shift of 89.5 meV is observed in case of mesoporous hybrid structure and the corresponding local electric field has been evaluated as 4.38×104 V/cm. The enhancement is assumed to be caused by greater density of charge in the mesoporous hybrid. The conjugation of superparamagnetic nanoparticles in this tailored hybrid microstructure has not imparted any alteration to the Stark shift, but has added multifunctional attribute. The present study on the local electric field induced enhanced QCSE with wavelength modulation towards red end paves the way of developing magneto-fluorescent hybrid systems for biomedical imaging application.

  2. Time-Dependent Configuration Interaction Approach for Multielectron System Confined in Two-Dimensional Quantum Dot

    NASA Astrophysics Data System (ADS)

    Okunishi, Takuma; Clark, Richard; Takeda, Kyozaburo; Kusakabe, Koichi; Tomita, Norikazu

    2013-02-01

    We extend the static multireference description (resonant unrestricted Hartree-Fock) to a dynamical system in order to include the correlation effect dynamically. The resulting time-dependent (TD) Schrödinger equation is simplified into the time-developed rate equation (TD-CI), where the TD external field \\hatH‧(t) is taken into account directly in the Hamiltonian without any approximations. This TD-CI approach also has an advantage in that it takes into account the electron correlation by narrowing down the number of employed Slater determinants. We apply our TD-CI approach to the case of two electrons confined in the square quantum dot (QD) having the spin singlet multiplicity, and study theoretically the spatial and temporal fluctuation of the two-electron ground state under photon injection and pulse field application.

  3. Microwave remote plasma enhanced-atomic layer deposition system with multicusp confinement chamber

    SciTech Connect

    Dechana, A.; Thamboon, P.; Boonyawan, D.

    2014-10-15

    A microwave remote Plasma Enhanced-Atomic Layer Deposition system with multicusp confinement chamber is established at the Plasma and Beam Physics research facilities, Chiang Mai, Thailand. The system produces highly-reactive plasma species in order to enhance the deposition process of thin films. The addition of the multicusp magnetic fields further improves the plasma density and uniformity in the reaction chamber. Thus, the system is more favorable to temperature-sensitive substrates when heating becomes unwanted. Furthermore, the remote-plasma feature, which is generated via microwave power source, offers tunability of the plasma properties separately from the process. As a result, the system provides high flexibility in choice of materials and design experiments, particularly for low-temperature applications. Performance evaluations of the system were carried on coating experiments of Al{sub 2}O{sub 3} layers onto a silicon wafer. The plasma characteristics in the chamber will be described. The resulted Al{sub 2}O{sub 3} films—analyzed by Rutherford Backscattering Spectrometry in channeling mode and by X-ray Photoelectron Spectroscopy techniques—will be discussed.

  4. Microwave remote plasma enhanced-atomic layer deposition system with multicusp confinement chamber

    NASA Astrophysics Data System (ADS)

    Dechana, A.; Thamboon, P.; Boonyawan, D.

    2014-10-01

    A microwave remote Plasma Enhanced-Atomic Layer Deposition system with multicusp confinement chamber is established at the Plasma and Beam Physics research facilities, Chiang Mai, Thailand. The system produces highly-reactive plasma species in order to enhance the deposition process of thin films. The addition of the multicusp magnetic fields further improves the plasma density and uniformity in the reaction chamber. Thus, the system is more favorable to temperature-sensitive substrates when heating becomes unwanted. Furthermore, the remote-plasma feature, which is generated via microwave power source, offers tunability of the plasma properties separately from the process. As a result, the system provides high flexibility in choice of materials and design experiments, particularly for low-temperature applications. Performance evaluations of the system were carried on coating experiments of Al2O3 layers onto a silicon wafer. The plasma characteristics in the chamber will be described. The resulted Al2O3 films—analyzed by Rutherford Backscattering Spectrometry in channeling mode and by X-ray Photoelectron Spectroscopy techniques—will be discussed.

  5. Fiber optic projection-imaging system for shape measurement in confined space.

    PubMed

    Chen, Lujie; Bavigadda, Viswanath; Kofidis, Theodoros; Howe, Robert D

    2014-01-01

    A fiber-based projection-imaging system is proposed for shape measurement in confined space. Owing to the flexibility of imaging fibers, the system can be used in special scenarios that are difficult for conventional experimental setups. Three experiments: open space, closed space, and underwater are designed to demonstrate the strength and weakness of the system. It is shown that when proper alignment is possible, relatively high accuracy can be achieved; the error is less than 2% of the overall height of a specimen. In situations where alignment is difficult, significantly increased error is observed. The error is in the form of gross-scale geometrical distortion; for example, flat surface is reconstructed with curvature. In addition, the imaging fibers may introduce fine-scale noise into phase measurement, which has to be suppressed by smoothing filters. Based on results and analysis, it is found that although a fiber-based system has its unique strength, existing calibration and processing methods for fringe patterns have to be modified to overcome its drawbacks so as to accommodate wider applications. PMID:24688368

  6. Fiber Optic Projection-Imaging System for Shape Measurement in Confined Space

    PubMed Central

    Chen, Lujie; Bavigadda, Viswanath; Kofidis, Theodoros; Howe, Robert D.

    2014-01-01

    A fiber-based projection-imaging system is proposed for shape measurement in confined space. Owing to the flexibility of imaging fibers, the system can be used in special scenarios that are difficult for conventional experimental setups. Three experiments: open space, closed space, and underwater are designed to demonstrate the strength and weakness of the system. It is shown that when proper alignment is possible, relatively high accuracy can be achieved; the error is less than 2% of the overall height of a specimen. In situations where alignment is difficult, significantly increased error is observed. The error is in the form of gross-scale geometrical distortion; for example, flat surface is reconstructed with curvature. In addition, the imaging fibers may introduce fine-scale noise into phase measurement, which has to be suppressed by smoothing filters. Based on results and analysis, it is found that although a fiber-based system has its unique strength, existing calibration and processing methods for fringe patterns have to be modified to overcome its drawbacks so as to accommodate wider applications. PMID:24688368

  7. Active optical zoom system

    DOEpatents

    Wick, David V.

    2005-12-20

    An active optical zoom system changes the magnification (or effective focal length) of an optical imaging system by utilizing two or more active optics in a conventional optical system. The system can create relatively large changes in system magnification with very small changes in the focal lengths of individual active elements by leveraging the optical power of the conventional optical elements (e.g., passive lenses and mirrors) surrounding the active optics. The active optics serve primarily as variable focal-length lenses or mirrors, although adding other aberrations enables increased utility. The active optics can either be LC SLMs, used in a transmissive optical zoom system, or DMs, used in a reflective optical zoom system. By appropriately designing the optical system, the variable focal-length lenses or mirrors can provide the flexibility necessary to change the overall system focal length (i.e., effective focal length), and therefore magnification, that is normally accomplished with mechanical motion in conventional zoom lenses. The active optics can provide additional flexibility by allowing magnification to occur anywhere within the FOV of the system, not just on-axis as in a conventional system.

  8. Secondary Confinement of Water Observed in Eutectic Melting of Aqueous Salt Systems in Nanopores.

    PubMed

    Meissner, Jens; Prause, Albert; Findenegg, Gerhard H

    2016-05-19

    Freezing and melting of aqueous solutions of alkali halides confined in the cylindrical nanopores of MCM-41 and SBA-15 silica was probed by differential scanning calorimetry (DSC). We find that the confinement-induced shift of the eutectic temperature in the pores can be significantly greater than the shift of the melting temperature of pure water. Greatest shifts of the eutectic temperature are found for salts that crystallize as oligohydrates at the eutectic point. This behavior is explained by the larger fraction of pore volume occupied by salt hydrates as compared to anhydrous salts, on the assumption that precipitated salt constitutes an additional confinement for ice/water in the pores. A model based on this secondary confinement effect gives a good representation of the experimental data. Salt-specific secondary confinement may play a role in a variety of fields, from salt-impregnated advanced adsorbents and catalysts to the thermal weathering of building materials. PMID:27124392

  9. THE ROTATING MAGNETIC FIELD OSCILLATOR SYSTEM FOR CURRENT DRIVE IN THE TRANSLATION, CONFINEMENT AND SUSTAINMENT EXPERIMENT

    SciTech Connect

    S. TOBIN; ET AL

    2000-12-01

    The experimental setup and test results for the {approximately}125 MW rotating magnetic field current drive system of the Translation, Confinement and Sustainment Experiment at the University of Washington are described. The oscillator system, constructed at Los Alamos National Laboratory, drives two tank circuits (15 kV{sub peak} potential, 8.5 kA{sub peak} maximum circulating current in each tank to date) operated 90{degree} out of phase to produce a 54 G rotating magnetic field with a frequency of 163 kHz ({omega} = 1.02{sup x} 10{sup {minus}6} s{sup {minus}1}). Programmable waveform generators control ''hot deck'' totem pole drivers that are used to control the grid of 12 Machlett 8618 magnetically beamed triode tubes. This setup allows the current to be turned on or off in less than 100 ns ({approximately}6{degree}). Both tank circuits are isolated from the current source by a 1:1 air core, transmission line transformer. Each tank circuit contains two saddle coils (combined inductance of 1.6 {micro}H) and radio frequency capacitors (580 nF). Test results are presented for three conditions: no external load, a resistive external load and a plasma load. A SPICE model of the oscillator system was created. Comparisons between this model and experimental data are given.

  10. Inertial Electrostatic Confinement Fusion: The Laser Elevator Solar System Survey for Propellants Abstract

    NASA Technical Reports Server (NTRS)

    Pryor, Wayne

    1999-01-01

    Dr. Wayne Pryor worked on three projects this summer. These were: 1) Inertial Electrostatic Confinement; 2) The Laser Elevator; and 3) Solar System Survey for Propellants Abstract. We Assisted Jon Nadler from Richland Community College in assembling and operating a table-top nuclear fusion reactor. We successfully demonstrated neutron production in a deuterium plasma. Pryor also obtained basic spectroscopic information on the atomic and molecular emissions in the plasma. The second project consisted of the completion of a paper on a novel propulsion concept (due to Tom Meyer of Colorado, the first author): a laser sail that bounces light back to the laser source. Recycling the photons from source to sail perhaps 100-1000 times dramatically improves the energy efficiency of this system, which may become very important for high-velocity missions in the future. Lastly, we compiled a very basic inventory of solar system propellant resources, their locations, and their accessibility. This initial inventory concentrates on sunlight availability, water availability, and the difficulty (delta-velocity requirement and radiation environment) in getting there.

  11. Bistability in a self-assembling system confined by elastic walls: Exact results in a one-dimensional lattice model

    SciTech Connect

    Pȩkalski, J.; Ciach, A.; Almarza, N. G.

    2015-01-07

    The impact of confinement on self-assembly of particles interacting with short-range attraction and long-range repulsion potential is studied for thermodynamic states corresponding to local ordering of clusters or layers in the bulk. Exact and asymptotic expressions for the local density and for the effective potential between the confining surfaces are obtained for a one-dimensional lattice model introduced by J. Pȩkalski et al. [J. Chem. Phys. 138, 144903 (2013)]. The simple asymptotic formulas are shown to be in good quantitative agreement with exact results for slits containing at least 5 layers. We observe that the incommensurability of the system size and the average distance between the clusters or layers in the bulk leads to structural deformations that are different for different values of the chemical potential μ. The change of the type of defects is reflected in the dependence of density on μ that has a shape characteristic for phase transitions. Our results may help to avoid misinterpretation of the change of the type of defects as a phase transition in simulations of inhomogeneous systems. Finally, we show that a system confined by soft elastic walls may exhibit bistability such that two system sizes that differ approximately by the average distance between the clusters or layers are almost equally probable. This may happen when the equilibrium separation between the soft boundaries of an empty slit corresponds to the largest stress in the confined self-assembling system.

  12. Fragmentation mechanisms of confined co-flowing capillary threads revealed by active flow focusing

    NASA Astrophysics Data System (ADS)

    Robert de Saint Vincent, Matthieu; Delville, Jean-Pierre

    2016-08-01

    The control over stationary liquid thread fragmentation in confined co-flows is a key issue for the processing and transport of fluids in (micro-)ducts. Confinement indeed strongly enhances the stability of capillary threads, and also induces steric and hydrodynamic feedback effects on diphasic flows. We investigate the thread-to-droplet transition within the confined environment of a microchannel by using optocapillarity, i.e., interface stresses driven by light, as a wall-free constriction to locally flow focus stable threads in a tunable way, pinch them, and force their fragmentation. Above some flow-dependent onset in optical forcing, we observe a dynamic transition alternating between continuous (thread) and fragmented (droplets) states and show a surprisingly gradual thread-to-droplet transition when increasing the amplitude of the thread constriction. This transition is interpreted as an evolution from a convective to an absolute instability. Depending on the forcing amplitude, we then identify and characterize several stable fragmented regimes of single and multiple droplet periodicity (up to period-8). These droplet regimes build a robust flow-independent bifurcation diagram that eventually closes up, due to the flow confinement, to a monodisperse droplet size, independent of the forcing and close to the most unstable mode expected from the Rayleigh-Plateau instability. This fixed monodispersity can be circumvented by temporally modulating the optocapillary coupling, as we show that fragmentation can then occur either by triggering again the Rayleigh-Plateau instability when the largest excitable wavelength is larger than that of the most unstable mode, or as a pure consequence of a sufficiently strong optocapillary pinching. When properly adjusted, this modulation allows us to avoid the transient reforming and multidisperse regimes, and thereby to reversibly produce stable monodisperse droplet trains of controlled size. By actuating local flow focusing in

  13. Phosphorene confined systems in magnetic field, quantum transport, and superradiance in the quasiflat band

    NASA Astrophysics Data System (ADS)

    Ostahie, B.; Aldea, A.

    2016-02-01

    Spectral and transport properties of electrons in confined phosphorene systems are investigated in a five hopping parameter tight-binding model, using analytical and numerical techniques. The main emphasis is on the properties of the topological edge states accommodated by the quasiflat band that characterizes the phosphorene energy spectrum. We show, in the particular case of phosphorene, how the breaking of the bipartite lattice structure gives rise to the electron-hole asymmetry of the energy spectrum. The properties of the topological edge states in the zigzag nanoribbons are analyzed under different aspects: degeneracy, localization, extension in the Brillouin zone, dispersion of the quasiflat band in magnetic field. The finite-size phosphorene plaquette exhibits a Hofstadter-type spectrum made up of two unequal butterflies separated by a gap, where a quasiflat band composed of zigzag edge states is located. The transport properties are investigated by simulating a four-lead Hall device (importantly, all leads are attached on the same zigzag side), and using the Landauer-Büttiker formalism. We find out that the chiral edge states due to the magnetic field yield quantum Hall plateaus, but the topological edge states in the gap do not support the quantum Hall effect and prove a dissipative behavior. By calculating the complex eigenenergies of the non-Hermitian effective Hamiltonian that describes the open system (plaquette+leads), we prove the superradiance effect in the energy range of the quasiflat band, with consequences for the density of states and electron transmission properties.

  14. HYPERFUSE: a hypervelocity inertial confinement system for fusion energy production and fission waste transmutation

    SciTech Connect

    Makowitz, H; Powell, J R; Wiswall, R

    1980-01-01

    Parametric system studies of an inertial confinement fusion (ICF) reactor system to transmute fission products from an LWR economy have been carried out. The ICF reactors would produce net power in addition to transmuting fission products. The particular ICF concept examined is an impact fusion approach termed HYPERFUSE, in which hypervelocity pellets, traveling on the order of 100 to 300 km/sec, collide with each other or a target block in a reactor chamber and initiate a thermonuclear reaction. The DT fusion fuel is contained in a shell of the material to be transmuted, e.g., /sup 137/Cs, /sup 90/Sr, /sup 129/I, /sup 99/Tc, etc. The 14-MeV fusion neutrons released during the pellet burn cause transmutation reactions (e.g., (n,2n), (n,..cap alpha..), (n,..gamma..), etc.) that convert the long-lived fission products (FP's) either to stable products or to species that decay with a short half-life to a stable product. The transmutation parametric studies conclude that the design of the hypervelocity projectiles should emphasize the achievement of high densities in the transmutation regions (greater than the DT fusion fuel density), as well as the DT ignition and burn criterion (rho R=1.0 to 3.0) requirements.

  15. Global versus local environmental impacts of grazing and confined beef production systems

    NASA Astrophysics Data System (ADS)

    Modernel, P.; Astigarraga, L.; Picasso, V.

    2013-09-01

    Carbon footprint is a key indicator of the contribution of food production to climate change and its importance is increasing worldwide. Although it has been used as a sustainability index for assessing production systems, it does not take into account many other biophysical environmental dimensions more relevant at the local scale, such as soil erosion, nutrient imbalance, and pesticide contamination. We estimated carbon footprint, fossil fuel energy use, soil erosion, nutrient imbalance, and risk of pesticide contamination for five real beef background-finishing systems with increasing levels of intensification in Uruguay, which were combinations of grazing rangelands (RL), seeded pastures (SP), and confined in feedlot (FL). Carbon footprint decreased from 16.7 (RL-RL) to 6.9 kg (SP-FL) CO2 eq kg body weight-1 (BW; ‘eq’: equivalent). Energy use was zero for RL-RL and increased up to 17.3 MJ kg BW-1 for SP-FL. Soil erosion values varied from 7.7 (RL-RL) to 14.8 kg of soil kg BW-1 (SP-FL). Nitrogen and phosphorus nutrient balances showed surpluses for systems with seeded pastures and feedlots while RL-RL was deficient. Pesticide contamination risk was zero for RL-RL, and increased up to 21.2 for SP-FL. For the range of systems studied with increasing use of inputs, trade-offs were observed between global and local environmental problems. These results demonstrate that several indicators are needed to evaluate the sustainability of livestock production systems.

  16. Modulation of environmental dynamics at the active site and activity of an enzyme under nanoscopic confinement: Subtilisin Carlsberg in anionic AOT reverse micelle.

    PubMed

    Rakshit, Surajit; Saha, Ranajay; Pal, Samir Kumar

    2013-10-01

    Hydration dynamics plays a crucial role in determining the structure, function, dynamics, and stability of an enzyme. These dynamics involve the trapped-water motions within small distance along with the total protein dynamics. However, the exact molecular basis for the induction of enzyme function by water dynamics is still remain unclear. Here, we have studied both enzymatic activity and environmental dynamics at the active site of an enzyme, Subtilisin Carlsberg (SC), under confined environment of the reverse micelle (RM) retaining the structural integrity of the protein. Kinetic measurements show that enzymatic activity increases with increasing the water content of the RM. The picosecond-resolved fluorescence Stokes shift studies indicate faster hydration dynamics at the active site of the enzyme with increasing the water content in the RM (w0 values). Temperature-dependent hydration dynamics studies demonstrate the increased flexibility of the protein at higher temperature under confinement. From temperature-dependent solvation dynamics study, we have also calculated the activation energy that has to be overcome for full orientational freedom to the water molecules from bound to free-state. The results presented here establish a correlation between the enzymatic activity and dynamics of hydration of the encapsulated protein SC in cell-like confined environment within the structural integrity of the enzyme. PMID:24004033

  17. PREFACE: Water in confined geometries

    NASA Astrophysics Data System (ADS)

    Rovere, Mauro

    2004-11-01

    The study of water confined in complex systems in solid or gel phases and/or in contact with macromolecules is relevant to many important processes ranging from industrial applications such as catalysis and soil chemistry, to biological processes such as protein folding or ionic transport in membranes. Thermodynamics, phase behaviour and the molecular mobility of water have been observed to change upon confinement depending on the properties of the substrate. In particular, polar substrates perturb the hydrogen bond network of water, inducing large changes in the properties upon freezing. Understanding how the connected random hydrogen bond network of bulk water is modified when water is confined in small cavities inside a substrate material is very important for studies of stability and the enzymatic activity of proteins, oil recovery or heterogeneous catalysis, where water-substrate interactions play a fundamental role. The modifications of the short-range order in the liquid depend on the nature of the water-substrate interaction, hydrophilic or hydrophobic, as well as on its spatial range and on the geometry of the substrate. Despite extensive study, both experimentally and by computer simulation, there remain a number of open problems. In the many experimental studies of confined water, those performed on water in Vycor are of particular interest for computer simulation and theoretical studies since Vycor is a porous silica glass characterized by a quite sharp distribution of pore sizes and a strong capability to absorb water. It can be considered as a good candidate for studying the general behaviour of water in hydrophilic nanopores. But there there have been a number of studies of water confined in more complex substrates, where the interpretation of experiments and computer simulation is more difficult, such as in zeolites or in aerogels or in contact with membranes. Of the many problems to consider we can mention the study of supercooled water. It is

  18. Medusa: A Novel Gene Drive System for Confined Suppression of Insect Populations

    PubMed Central

    Marshall, John M.; Hay, Bruce A.

    2014-01-01

    Gene drive systems provide novel opportunities for insect population suppression by driving genes that confer a fitness cost into pest or disease vector populations; however regulatory issues arise when genes are capable of spreading across international borders. Gene drive systems displaying threshold properties provide a solution since they can be confined to local populations and eliminated through dilution with wild-types. We propose a novel, threshold-dependent gene drive system, Medusa, capable of inducing a local and reversible population crash. Medusa consists of four components - two on the X chromosome, and two on the Y chromosome. A maternally-expressed, X-linked toxin and a zygotically-expressed, Y-linked antidote results in suppression of the female population and selection for the presence of the transgene-bearing Y because only male offspring of Medusa-bearing females are protected from the effects of the toxin. At the same time, the combination of a zygotically-expressed, Y-linked toxin and a zygotically-expressed, X-linked antidote selects for the transgene-bearing X in the presence of the transgene-bearing Y. Together these chromosomes create a balanced lethal system that spreads while selecting against females when present above a certain threshold frequency. Simple population dynamic models show that an all-male release of Medusa males, carried out over six generations, is expected to induce a population crash within 12 generations for modest release sizes on the order of the wild population size. Re-invasion of non-transgenic insects into a suppressed population can result in a population rebound; however this can be prevented through regular releases of modest numbers of Medusa males. Finally, we outline how Medusa could be engineered with currently available molecular tools. PMID:25054803

  19. CCSD(T) calculations of stabilities and properties of confined systems

    SciTech Connect

    Holka, F.; Urban, M.; Melicherčík, M.; Neogrády, P.; Paldus, J.

    2015-01-22

    We analyze energies, electron affinities and polarizabilities of small anions exposed to an external confinement. The second electron in free O{sup 2−} and S{sup 2−} anions is unbound. We investigate the stabilizing effect of the spherical harmonic-oscillator confining potential ω. on these anions employing the Hartree-Fock stability analysis as introduced by Čížek and Paldus. With increasing strength of the external harmonic-oscillator confinement potential ω the broken symmetry (BS) solutions are systematically eliminated. For ω larger than 0.1 all BS solutions for O{sup 2−} disappear. For ω larger than 0.13 the CCSD(T) energy of O{sup 2−} becomes more negative than the energy of the singly charged O{sup −} anion. We relate the harmonic-oscillator confining potential to a crystalline environment in which the O{sup 2−} and S{sup 2−} anions are stable. We also present a model allowing calculations of the in-crystal polarizabilities of anions. The model is based on CCSD(T) calculations of static polarizabilities of selected anions exposed to the spherical harmonic-oscillator confining potential ω This artificial confinement potential ω is then related to the ionic radii of the cation in representative crystal lattices. We investigate the polarizability of O{sup 2−} and S{sup 2−} anions in MgO, MgS, CaO, CaS, SrO, SrS, BaO and BaS crystals. We compare our results with alternative models for in-crystal polarizabilities. External confinement also stabilizes the uracil anion U{sup −}, as is shown by calculations with a stepwise micro-hydration of U{sup −}. Upon hydration is the CCSD(T) adiabatic electron affinity (AEA) of uracil enhanced by about 250 up to 570 meV in comparison with AEA of the isolated molecule, depending on the geometry of the hydrated uracil anion complex. We tried to find an analogy of the stabilization effect of the external confinement on the otherwise unstable anions. In uracil and its anion is the external

  20. Spectral broadening and electron-photon coupling in III-V infrared detectors of low dimensional quantum confined system

    NASA Astrophysics Data System (ADS)

    Joy, Soumitra R.; Mohammedy, Farseem M.

    2016-05-01

    Present work explores the mid-IR photodetection mechanism in III-V quantum confined system in twofold ways. Firstly, it models the extent of spectral linewidth broadening of photo-detector. Secondly, it investigates whether a strong perturbation of light can modulate the electronic bandstructure. Photo-absorption mechanism in the detector correlated to reduced carrier lifetime in ground state leading to homogeneous spectral widening is calculated. Besides, contribution of non-uniform size and composition of quantum dots towards spectral broadening is modeled in order to get the envelop of inhomogeneously broadened photocurrent spectrum. Our model generates photocurrent spectrum with 1.4 μm broadening centered at 3.5 μm at 77 K for a DWELL-IP, which agrees with the experimental result. The calculated photocurrent spectral width of 1.3 μm for GaAs/AlGaAs Quantum Well (QW) centered at 8.31 μm at 77 K also supports experimental data. In addition, our calculation reveals the emergence of a broad resonant peak in the spectrum of QW-IP in far infrared region (20-50 μm) as the photon volume density increases up to 0.1% of carrier density inside the active region. We introduce a hybrid density-of-states for strongly coupled electron-photon system to explain both mid and far IR peak.

  1. Effects of patterning and spatial confinement on order in self-assembling systems

    NASA Astrophysics Data System (ADS)

    Hung, Albert Melvin

    2007-12-01

    Supramolecular chemistry has proven to be an effective strategy for bottom-up fabrication of monodisperse, functional nanostructures. However, most applications require these nanostructures to be spatially or orientationally ordered. This thesis investigates patterning and spatial confinement as tools for controlling order in self-assembling systems. We first look to improve the ordering of polar, mushroom-shaped supramolecular aggregates through surface chemistry and addition of small molecule guests. Monolayer and bilayer films are 1 nm/layer thicker on hydrophilic oxide versus hydrophobic surfaces, suggesting more normal orientation and tighter packing of the molecules. By FTIR, 4-cyanobiphenyl incorporated into these films align normal to the surface with an order parameter ftheta = 0.38. ftheta of the host also increases from 0.2 to 0.7, possibly due to occupation of free volume and release of strain about the mushroom "stems" by the guest. We next develope methods for patterning and aligning 1D, supramolecular peptide-amphiphile (PA) nanofibers. Microcontact printing can directly pattern nanofiber arrays of submicrometer resolution. The features size increases with stamping time and glycerol concentration. Depending on the molecule, PA is deposited by direct contact or fluid transport through a water meniscus. By another method, sonication-assisted solution embossing, we achieve the simultaneous self-assembly, alignment and patterning of nanofibers over large areas. Alignment is due to steric confinement within submicrometer channels and a lyotropic liquid crystalline transition. Nanofibers can also be guided around turns by this technique. FTIR gives nanofiber orientation parameters of 0.2 to 0.4 and confirms that the nanostructures consist of axially aligned beta-sheets. Neural progenitor cells show preferential alignment of cell bodies parallel to these aligned nanofibers, hypothetically due to integrin clustering about the nanofibers leading to a

  2. Development of the large neutron imaging system for inertial confinement fusion experiments.

    PubMed

    Caillaud, T; Landoas, O; Briat, M; Kime, S; Rossé, B; Thfoin, I; Bourgade, J L; Disdier, L; Glebov, V Yu; Marshall, F J; Sangster, T C

    2012-03-01

    Inertial confinement fusion (ICF) requires a high resolution (~10 μm) neutron imaging system to observe deuterium and tritium (DT) core implosion asymmetries. A new large (150 mm entrance diameter: scaled for Laser MégaJoule [P. A. Holstein, F. Chaland, C. Charpin, J. M. Dufour, H. Dumont, J. Giorla, L. Hallo, S. Laffite, G. Malinie, Y. Saillard, G. Schurtz, M. Vandenboomgaerde, and F. Wagon, Laser and Particle Beams 17, 403 (1999)]) neutron imaging detector has been developed for such ICF experiments. The detector has been fully characterized using a linear accelerator and a (60)Co γ-ray source. A penumbral aperture was used to observe DT-gas-filled target implosions performed on the OMEGA laser facility. [T. R. Boehly, D. L. Brown, R. S. Craxton, R. L. Keck, J. P. Knauer, J. H. Kelly, T. J. Kessler, S. A. Kumpan, S. J. Loucks, S. A. Letzring, F. J. Marshall, R. L. McCrory, S. F. B. Morse, W. Seka, J. M. Soures, and C. P. Verdon, Opt. Commun. 133, 495 (1997)] Neutron core images of 14 MeV with a resolution of 15 μm were obtained and are compared to x-ray images of comparable resolution. PMID:22462917

  3. Development of the large neutron imaging system for inertial confinement fusion experiments

    NASA Astrophysics Data System (ADS)

    Caillaud, T.; Landoas, O.; Briat, M.; Kime, S.; Rossé, B.; Thfoin, I.; Bourgade, J. L.; Disdier, L.; Glebov, V. Yu.; Marshall, F. J.; Sangster, T. C.

    2012-03-01

    Inertial confinement fusion (ICF) requires a high resolution (˜10 μm) neutron imaging system to observe deuterium and tritium (DT) core implosion asymmetries. A new large (150 mm entrance diameter: scaled for Laser MégaJoule [P. A. Holstein, F. Chaland, C. Charpin, J. M. Dufour, H. Dumont, J. Giorla, L. Hallo, S. Laffite, G. Malinie, Y. Saillard, G. Schurtz, M. Vandenboomgaerde, and F. Wagon, Laser and Particle Beams 17, 403 (1999), 10.1017/S0263034699173087]) neutron imaging detector has been developed for such ICF experiments. The detector has been fully characterized using a linear accelerator and a 60Co γ-ray source. A penumbral aperture was used to observe DT-gas-filled target implosions performed on the OMEGA laser facility. [T. R. Boehly, D. L. Brown, R. S. Craxton, R. L. Keck, J. P. Knauer, J. H. Kelly, T. J. Kessler, S. A. Kumpan, S. J. Loucks, S. A. Letzring, F. J. Marshall, R. L. McCrory, S. F. B. Morse, W. Seka, J. M. Soures, and C. P. Verdon, Opt. Commun. 133, 495 (1997), 10.1016/S0030-4018(96)00325-2] Neutron core images of 14 MeV with a resolution of 15 μm were obtained and are compared to x-ray images of comparable resolution.

  4. First Principles Real-Space GW+BSE Calculations for Confined Systems

    NASA Astrophysics Data System (ADS)

    Hung, Linda; Ogut, Serdar; Souto, Jaime; Lee, Alex; Lena, Charles; Chelikowsky, James R.; Jornada, Felipe H. Da; Louie, Steven G.

    2014-03-01

    We investigate the performance of various levels of GW theories for electronic excitations as well as the resulting solutions of the Bethe-Salpeter-Equation (BSE) for optical excitations in a wide range of confined systems including atoms, ions, diatomic molecules, and organic molecules relevant for photovoltaic applications. Starting with solutions of the Kohn-Sham equations for ground state properties computed via the real-space ab initio pseudopotential code PARSEC, we perform the GW calculations in the space of single-particle transitions at various levels of theory, and compare the results with photoemission data. The levels of theory include such approximations as G0W0 with RPA screening, G0Wf that includes vertex corrections through the use of a dielectric screening within the time-dependent-local-density approximation (TDLDA), the GW0 , and the self-consistent GW. The resulting quasiparticle energies and wave functions from the GW calculations are used to solve the BSE for optical excitations, which are then compared with experiments and results from calculations performed within the TDLDA. The effects of the vertex corrections, self-consistency in GW, and core-valence partitioning are discussed. Supported by DOE Grant No. DE-SC0001853.

  5. Inertial confinement fusion reaction chamber and power conversion system study. Final report

    SciTech Connect

    Maya, I.; Schultz, K.R.; Bourque, R.F.; Cheng, E.T.; Creedon, R.L.; Norman, J.H.; Price, R.J.; Porter, J.; Schuster, H.L.; Simnad, M.J.

    1985-10-01

    This report summarizes the results of the second year of a two-year study on the design and evaluation of the Cascade concept as a commercial inertial confinement fusion (ICF) reactor. We developed a reactor design based on the Cascade reaction chamber concept that would be competitive in terms of both capital and operating costs, safe and environmentally acceptable in terms of hazard to the public, occupational exposure and radioactive waste production, and highly efficient. The Cascade reaction chamber is a double-cone-shaped rotating drum. The granulated solid blanket materials inside the rotating chamber are held against the walls by centrifugal force. The fusion energy is captured in a blanket of solid carbon, BeO, and LiAlO/sub 2/ granules. These granules are circulated to the primary side of a ceramic heat exchanger. Primary-side granule temperatures range from 1285 K at the LiAlO/sub 2/ granule heat exchanger outlet to 1600 K at the carbon granule heat exchanger inlet. The secondary side consists of a closed-cycle gas turbine power conversion system with helium working fluid, operating at 1300 K peak outlet temperature and achieving a thermal power conversion efficiency of 55%. The net plant efficiency is 49%. The reference design is a plant producing 1500 MW of D-T fusion power and delivering 815 MW of electrical power for sale to the utility grid. 88 refs., 44 figs., 47 tabs.

  6. HYPERFUSE: a hypervelocity inertial confinement system for fusion energy production and fission waste transmutation

    SciTech Connect

    Makowitz, H.; Powell, J.R.; Wiswall, R.

    1980-01-01

    Parametric system studies of an inertial confinement fusion (ICF) reactor system to transmute fission products from a LWR economy have been carried out. The ICF reactors would produce net power in addition to transmuting fission products. The particular ICF concept examined is an impact fusion approach termed HYPERFUSE, in which hypervelocity pellets, traveling on the order of 100 to 300 km/sec, collide with each other or a target block in a reactor chamber and initiate a thermonuclear reaction. The DT fusion fuel is contained in a shell of the material to be transmuted, e.g., /sup 137/Cs, /sup 90/Sr, /sup 129/I, /sup 99/Tc, etc. The 14-MeV fusion neutrons released during the pellet burn cause transmutation reactions (e.g., (n,2n), (n,..cap alpha..), (n,..gamma..), etc.) that convert the long-lived fission products (FP's) either to stable products or to species that decay with a short half-life to a stable product. The transmutation parametric studies conclude that the design of the hypervelocity projectiles should emphasize the achievement of high densities in the transmutation regions (greater than the DT fusion fuel density), as well as the DT ignition and burn criterion (rho R = 1.0 to 3.0) requirements. These studies also indicate that masses on the order of 1.0 g at densities of rho greater than or equal to 500.0 g/cm/sup 3/ are required for a practical fusion-based fission product transmutation system.

  7. Structure and catalytic activities of ferrous centers confined on the interface between carbon nanotubes and humic acid.

    PubMed

    Wang, Bing; Zhou, Xiaoyan; Wang, Dongqi; Yin, Jun-Jie; Chen, Hanqing; Gao, Xingfa; Zhang, Jing; Ibrahim, Kurash; Chai, Zhifang; Feng, Weiyue; Zhao, Yuliang

    2015-02-14

    Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing π electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C=C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the ferrous sites. The experimental and theoretical results revealed octahedrally/tetrahedrally coordinated geometry at Fe centers, and the strong hybridization between CNT C π* and Fe 3d orbitals induces discretization of the atomic charges on aromatic rings of CNTs, which facilitates O2 adsorption and electron transfer from carbon to O2, which enhances O2 activation. The O2 activation by the novel HA/Fe-CNT complex can be applied in the oxidative degradation of phenol red (PR) and bisphenol A (BPA) in aqueous media. PMID:25580558

  8. Virial pressure in systems of spherical active Brownian particles.

    PubMed

    Winkler, Roland G; Wysocki, Adam; Gompper, Gerhard

    2015-09-01

    The pressure of suspensions of self-propelled objects is studied theoretically and by simulation of spherical active Brownian particles (ABPs). We show that for certain geometries, the mechanical pressure as force/area of confined systems can be equally expressed by bulk properties, which implies the existence of a nonequilibrium equation of state. Exploiting the virial theorem, we derive expressions for the pressure of ABPs confined by solid walls or exposed to periodic boundary conditions. In both cases, the pressure comprises three contributions: the ideal-gas pressure due to white-noise random forces, an activity-induced pressure ("swim pressure"), which can be expressed in terms of a product of the bare and a mean effective particle velocity, and the contribution by interparticle forces. We find that the pressure of spherical ABPs in confined systems explicitly depends on the presence of the confining walls and the particle-wall interactions, which has no correspondence in systems with periodic boundary conditions. Our simulations of three-dimensional ABPs in systems with periodic boundary conditions reveal a pressure-concentration dependence that becomes increasingly nonmonotonic with increasing activity. Above a critical activity and ABP concentration, a phase transition occurs, which is reflected in a rapid and steep change of the pressure. We present and discuss the pressure for various activities and analyse the contributions of the individual pressure components. PMID:26221908

  9. Confined Activation and Subdiffractive Localization Enables Whole-Cell PALM with Genetically Expressed Probes

    PubMed Central

    York, Andrew G.; Ghitani, Alireza; Vaziri, Alipasha; Davidson, Michael W.; Shroff, Hari

    2011-01-01

    We demonstrate 3D superresolution microscopy in whole fixed cells using photoactivated localization microscopy (PALM). The use of the bright, genetically expressed fluorescent marker photoactivatable mCherry (PA-mCherry1) in combination with near diffraction-limited confinement of photoactivation using two-photon illumination and 3D localization methods allowed us to investigate a variety of cellular structures at <50 nm lateral and <100 nm axial resolution. Compared to existing methods, we substantially reduce excitation and bleaching of unlocalized markers, enabling 3D PALM imaging with high localization density in thick structures. Our 3D localization algorithms based on cross-correlation do not rely on idealized noise models or specific optical configurations, allowing flexible instrument design. Generation of appropriate fusion constructs and expression in Cos7 cells allowed us to image invaginations of the nuclear membrane, vimentin fibrils, the mitochondrial network, and the endoplasmic reticulum at depths greater than 8 μm. PMID:21317909

  10. Highly Active Nanoreactors: Patchlike or Thick Ni Coating on Pt Nanoparticles Based on Confined Catalysis.

    PubMed

    Qi, Xinhong; Li, Xiangcun; Chen, Bo; Lu, Huilan; Wang, Le; He, Gaohong

    2016-01-27

    Catalyst-containing nanoreactors have attracted considerable attention for specific applications. Here, we initially report preparation of PtNi@SiO2 hollow microspheres based on confined catalysis. The previous encapsulation of dispersed Pt nanoparticles (NPs) in hollow silica microspheres ensures the formation of Pt@Ni coreshell NPs inside the silica porous shell. Thus, the Pt NPs not only catalyze the reduction of Ni ions but also direct Ni deposition on the Pt cores to obtain Pt@Ni core-shell catalyst. It is worthy to point out that this synthetic approach helps to form a patchlike or thick Ni coating on Pt cores by controlling the penetration time of Ni ions from the bulk solution into the SiO2 microspheres (0.5, 1, 2, or 4 h). Notably, the Pt@Ni core-shell NPs with a patch-like Ni layer on Pt cores (0.5 and 1 h) show a higher H2 generation rate of 1221-1475 H2 mL min(-1) g(-1)cat than the Pt@Ni NPs with a thick Ni layer (2 and 4 h, 920-1183 H2 mL min(-1) g(-1)cat), and much higher than that of pure Pt NPs (224 H2 mL min(-1) g(-1)cat). In addition, the catalyst possesses good stability and recyclability for H2 generation. The Pt@Ni core-shell NPs confined inside silica nanocapsules, with well-defined compositions and morphologies, high H2 generation rate, and recyclability, should be an ideal catalyst for specific applications in liquid phase reaction. PMID:26725500

  11. Entropic transport in confined media: a challenge for computational studies in biological and soft-matter systems

    NASA Astrophysics Data System (ADS)

    Malgaretti, Paolo; Pagonabarraga, Ignacio; Rubi, J. Miguel

    2013-11-01

    Transport in small-scale biological and soft-matter systems typically occurs under confinement conditions in which particles proceed through obstacles and irregularities of the boundaries that may significantly alter their trajectories. A transport model that assimilates the confinement to the presence of entropic barriers provides an efficient approach to quantify its effect on the particle current and the diffusion coefficient. We review the main peculiarities of entropic transport and treat two cases in which confinement effects play a crucial role, with the appearance of emergent properties. The presence of entropic barriers modifies the mean first-passage time distribution and therefore plays a very important role in ion transport through micro- and nano-channels. The functionality of molecular motors, modeled as Brownian ratchets, is strongly affected when the motor proceeds in a confined medium that may constitute another source of rectification. The interplay between ratchet and entropic rectification gives rise to a wide variety of dynamical behaviors, not observed when the Brownian motor proceeds in an unbounded medium. Entropic transport offers new venues of transport control and particle manipulation and new ways to engineer more efficient devices for transport at the nanoscale.

  12. An adaptive optics system for solid-state laser systems used in inertial confinement fusion

    SciTech Connect

    Salmon, J.T.; Bliss, E.S.; Byrd, J.L.; Feldman, M.; Kartz, M.A.; Toeppen, J.S.; Wonterghem, B. Van; Winters, S.E.

    1995-09-17

    Using adaptive optics the authors have obtained nearly diffraction-limited 5 kJ, 3 nsec output pulses at 1.053 {micro}m from the Beamlet demonstration system for the National Ignition Facility (NIF). The peak Strehl ratio was improved from 0.009 to 0.50, as estimated from measured wavefront errors. They have also measured the relaxation of the thermally induced aberrations in the main beam line over a period of 4.5 hours. Peak-to-valley aberrations range from 6.8 waves at 1.053 {micro}m within 30 minutes after a full system shot to 3.9 waves after 4.5 hours. The adaptive optics system must have enough range to correct accumulated thermal aberrations from several shots in addition to the immediate shot-induced error. Accumulated wavefront errors in the beam line will affect both the design of the adaptive optics system for NIF and the performance of that system.

  13. Challenges in Estimating Groundwater Recharge in Semi-arid and Semi-confined Alluvial Systems

    NASA Astrophysics Data System (ADS)

    Larsen, J.; Finch, W.; McIntyre, N.

    2015-12-01

    Uncertainty surrounding rates of groundwater recharge limits overall confidence in groundwater allocations and can lead to over-conservative assumptions in groundwater impact assessments. This problem is even more acute where more complex unsaturated flow paths are considered, such as within semi-confined alluvial systems. Researchers at The University of Queensland have developed an experimental study within the Condamine Alluvium, a significant aquifer in semi-arid eastern Australia, is used to determine groundwater recharge mechanisms for three distinct soil types (two vertosols and one chromosol) on both irrigated and non-irrigated areas. This variety of soil types, including shrink-swell clays, overly a higher permeability sand and gravel unsaturated zone and aquifer. The analysis uses 15-minute soil moisture data from Sentek EnviroSCAN Probe devices installed at 16 sites, with eight sensors in each site at depths from 100 to 4000mm. The vertosols exhibited signs of dynamic preferential flow paths due to the shrink swell properties of the soil. Precipitation rate and initial soil moisture content affect the infiltration response times for the three soils, with the chromosols requiring multiple precipitation events before experiencing any significant soil moisture storage changes in the lower depths (2000 - 4000mm). Storage changes below the root zone to a depth of 4m indicate large rates of potential recharge, up to 1300mm for the two years of data obtained. However, minimal rise has been observed in the water table (~12 m depth), potentially due to the highly transmissive sand and gravel aquifer. The analysis has shown that only very high temporal resolution monitoring of soil storage changes can effectively capture the dynamic preferential flow water flux. Lower temporal resolution monitoring, at the daily scale or greater, will bias the storage change estimates towards the matrix flow component and risk significant underestimation of the total unsaturated

  14. Economics of fertility in high-yielding dairy cows on confined TMR systems.

    PubMed

    Cabrera, V E

    2014-05-01

    The objective of this review paper was to summarise the latest findings in dairy cattle reproductive economics with an emphasis on high yielding, confined total mixed ration systems. The economic gain increases as the reproductive efficiency improves. These increments follow the law of diminishing returns, but are still positive even at high reproductive performance. Reproductive improvement results in higher milk productivity and, therefore, higher milk income over feed cost, more calf sales and lower culling and breeding expenses. Most high-yielding herds in the United States use a combination of timed artificial insemination (TAI) and oestrous detection (OD) reproductive programme. The ratio of achievable pregnancies between OD and TAI determines the economic value difference between both and their combinations. Nonetheless, complex interactions between reproductive programme, herd relative milk yield, and type of reproductive programme are reported. For example, higher herd relative milk yield would favour programme relying more on TAI. In addition, improved reproductive efficiency produces extra replacements. The availability of additional replacements could allow more aggressive culling policies (e.g. less services for non-pregnant cows) to balance on-farm supply and demand of replacements. Balancing heifer replacement availability in an efficient reproductive programme brings additional economic benefits. New technologies such as the use of earlier chemical tests for pregnancy diagnosis could be economically effective depending on the goals and characteristics of the farm. Opportunities for individual cow reproductive management within defined reproductive programme exist. These decisions would be based on economic metrics derived from the value of a cow such as the value of a new pregnancy, the cost of a pregnancy loss, or the cost of an extra day open. PMID:24679357

  15. A model system for a fluorometric biosensor using permeabilized Zymomonas mobilis or enzymes with protein confined dinucleotides

    SciTech Connect

    Thordsen, O.; Lee, S.J.; Degelau, A. ); Scheper, T. ); Loos, H.; Rehr, B.; Sahm, H. )

    1993-07-01

    Using permeabilized Zymomonas mobilis or glucose-fructose oxidoreductase isolated from this microorganism a model system for biosensors with a protein confined NADP(H) cofactor for the determination of glucose, fructose, gluconolactone, and sorbitol was developed. Either permeabilized microorganisms containing the oxidoreductase or the pure enzyme were confined via membrane separation in a small measuring chamber, that was integrated into a flow injection analysis system (FIA). The measuring principle was the monitoring of the NAD(P)H fluorescence, excited at 360 nm and measured at 450 nm. NADP(H), which is confined in the protein complex, was oxidized or reduced during the enzymatic reactions and the changes in the fluorescence intensity were related to the substrate concentration. The sensitivity of the system covered a range from 0.001 to 100 g/L of the analyte depending on substrate and operating conditions. The applicability of this model system for bioprocess monitoring was proved using samples from a Pseudomonas pseudoflava cultivation.

  16. The effect of artesian-pressure decline on confined aquifer systems and its relation to land subsidence

    USGS Publications Warehouse

    Green, J.H.

    1964-01-01

    Ground water in the Southwestern United States is derived chiefly from unconsolidated to semiconsolidated alluvial deposits. Where these deposits contain confined water, they may be susceptible to compaction and related land- surface subsidence, if artesian pressures are reduced. Compaction of artesian-aquifer systems can be estimated from core tests if the artesian-pressure decline is known. Compaction occurs chiefly in the finer grained deposits ; porosity decrease is greater near the top of the confined aquifer than near the bottom. Because most of the compaction of these aquifer systems is permanent, the storage coefficient during the initial decline of artesian pressure greatly exceeds the storage coefficient during a subsequent pressure decline through the same depth range, after an intervening period of pressure recovery.

  17. Solar cell activation system

    SciTech Connect

    Apelian, L.

    1983-07-05

    A system for activating solar cells involves the use of phosphorescent paint, the light from which is amplified by a thin magnifying lens and used to activate solar cells. In a typical system, a member painted with phosphorescent paint is mounted adjacent a thin magnifying lens which focuses the light on a predetermined array of sensitive cells such as selenium, cadmium or silicon, mounted on a plastic board. A one-sided mirror is mounted adjacent the cells to reflect the light back onto said cells for purposes of further intensification. The cells may be coupled to rechargeable batteries or used to directly power a small radio or watch.

  18. Fluid and Kinetic Modelling on Timescales Longer than the Confinement Time in Bounded Systems

    SciTech Connect

    Weiland, Jan; Zagorodny, Anatoly; Zasenko, Volodymyr

    2009-10-08

    The problem of fluid modelling on timescales longer than the confinement time is addressed as a problem of decay of high order moments without sources. Several mechanisms for the decay of higher order moments are discussed and very strong experimental evidence is given for toroidal plasmas.

  19. Structure and catalytic activities of ferrous centers confined on the interface between carbon nanotubes and humic acid

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Zhou, Xiaoyan; Wang, Dongqi; Yin, Jun-Jie; Chen, Hanqing; Gao, Xingfa; Zhang, Jing; Ibrahim, Kurash; Chai, Zhifang; Feng, Weiyue; Zhao, Yuliang

    2015-01-01

    Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing π electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C&z.dbd;C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the ferrous sites. The experimental and theoretical results revealed octahedrally/tetrahedrally coordinated geometry at Fe centers, and the strong hybridization between CNT C π* and Fe 3d orbitals induces discretization of the atomic charges on aromatic rings of CNTs, which facilitates O2 adsorption and electron transfer from carbon to O2, which enhances O2 activation. The O2 activation by the novel HA/Fe-CNT complex can be applied in the oxidative degradation of phenol red (PR) and bisphenol A (BPA) in aqueous media.Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing π electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C&z.dbd;C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the

  20. Production Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Gallaway, Ann, Ed.

    This production systems guide provides teachers with learning activities for secondary students. Introductory materials include an instructional planning outline and worksheet, an outline of essential elements, domains and objectives, a course description, and a content outline. The guide contains 30 modules on the following topics: production…

  1. Communication Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Sutherland, Barbara, Ed.

    This communication systems guide provides teachers with learning activities for secondary students. Introductory materials include an instructional planning outline and worksheet, an outline of essential elements, a list of objectives, a course description, and a content outline. The guide contains 32 modules on the following topics: story…

  2. Elastic membranes in confinement

    NASA Astrophysics Data System (ADS)

    Bostwick, Joshua; Miksis, Michael; Davis, Stephen

    2014-11-01

    An elastic membrane stretched between two walls takes a shape defined by its length and the volume of fluid it encloses. Many biological structures, such as cells, mitochondria and DNA, have finer internal structure in which a membrane (or elastic member) is geometrically ``confined'' by another object. We study the shape stability of elastic membranes in a ``confining'' box and introduce repulsive van der Waals forces to prevent the membrane from intersecting the wall. We aim to define the parameter space associated with mitochondria-like deformations. We compare the confined to `unconfined' solutions and show how the structure and stability of the membrane shapes changes with the system parameters.

  3. System and method for confining an object to a region of fluid flow having a stagnation point

    NASA Technical Reports Server (NTRS)

    Schroeder, Charles M. (Inventor); Shaqfeh, Eric S. G. (Inventor); Babcock, Hazen P. (Inventor); Chu, Steven (Inventor)

    2006-01-01

    A device for confining an object to a region proximate to a fluid flow stagnation point includes one or more inlets for carrying the fluid into the region, one or more outlets for carrying the fluid out of the region, and a controller, in fluidic communication with the inlets and outlets, for adjusting the motion of the fluid to produce a stagnation point in the region, thereby confining the object to the region. Applications include, for example, prolonged observation of the object, manipulation of the object, etc. The device optionally may employ a feedback control mechanism, a sensing apparatus (e.g., for imaging), and a storage medium for storing, and a computer for analyzing and manipulating, data acquired from observing the object. The invention further provides methods of using such a device and system in a number of fields, including biology, chemistry, physics, material science, and medical science.

  4. Chlorine stable isotope evidence for salinization processes of confined groundwater in southwestern Nobi Plain aquifer system, central Japan

    NASA Astrophysics Data System (ADS)

    Yamanaka, Masaru; Bottrell, Simon H.; Wu, Jiahong; Kumagai, Yoshihiro; Mori, Kazuki; Satake, Hiroshi

    2014-11-01

    A confined aquifer system, isolated from modern seawater, is developed in argillaceous marine and freshwater sediments of Pliocene-Holocene age in southwestern Nobi Plain (SWNP), central Japan. A tongue of brackish confined groundwater (Cl- >1000 mg/L), which extends from the shoreline of Ise Bay inland, mostly has negative δ37Cl values with -0.90‰ to 0.21‰. The Cl isotopic compositions are negatively correlated with paleo seawater Cl- concentrations discriminated by a Rayleigh distillation model with δ34S values, while they are not correlated with either total Cl- concentrations or δ34S values. Furthermore, Cl- concentrations from modern seawater are positively correlated with δ37Cl values. In addition to these observations, diffusion model calculations suggest that paleo seawater Cl- has diffused out from argillaceous marine sediments whereas modern seawater Cl- has not been affected by preferential diffusion of Cl isotopes because it has migrated by advection via both an unconfined aquifer and non-pumping wells. Moreover, the brackish groundwater is characterized by an excess of Na/Cl ratio and deficits of Mg/Cl and Ca/Cl ratios compared to those predicted from simple mixing of freshwater with seawater. This would be caused by cation exchange reactions in the confined aquifer system in which groundwater is freshening after salinization by both paleo seawater and/or modern seawater.

  5. Strongly confined tunnel-coupled one-dimensional electron systems from an asymmetric double quantum well

    NASA Astrophysics Data System (ADS)

    Buchholz, S. S.; Fischer, S. F.; Kunze, U.; Schuh, D.; Abstreiter, G.

    2008-03-01

    Vertically stacked quantum point contacts (QPCs) are prepared by atomic force microscope (AFM) lithography from an asymmetric GaAs/AlGaAs double quantum well (DQW) heterostructure. Top- and back-gate voltages are used to tune the tunnel-coupled QPCs, and back-gate bias cooling is employed to investigate coupled and decoupled one-dimensional (1D) modes. Parity dependent mode coupling is invoked by the particular asymmetry in the vertical DQW confinement.

  6. ADASY (Active Daylighting System)

    NASA Astrophysics Data System (ADS)

    Vázquez-Moliní, Daniel; González-Montes, Mario; Fernández-Balbuena, Antonio Á.; Bernabéu, Eusebio; García-Botella, Ángel; García-Rodríguez, Lucas; Pohl, Wilfried

    2009-08-01

    The main objective of ADASY (Active Daylighting System) work is to design a façade static daylighting system oriented to office applications, mainly. The goal of the project is to save energy by guiding daylight into a building for lighting purpose. With this approach we can reduce the electrical load for artificial lighting, completing it with sustainable energy. The collector of the system is integrated on a vertical façade and its distribution guide is always horizontal inside of the false ceiling. ADASY is designed with a specific patent pending caption system, a modular light-guide and light extractor luminaire system. Special care has been put on the final cost of the system and its building integration purpose. The current ADASY configuration is able to illuminate 40 m2 area with a 300lx-400lx level in the mid time work hours; furthermore it has a good enough spatial uniformity distribution and a controlled glare. The data presented in this study are the result of simulation models and have been confirmed by a physical scaled prototype. ADASY's main advantages over regular illumination systems are: -Low maintenance; it has not mobile pieces and therefore it lasts for a long time and require little attention once installed. - No energy consumption; solar light continue working even if there has been a power outage. - High quality of light: the colour rendering of light is very high - Psychological benefits: People working with daylight get less stress and more comfort, increasing productivity. - Health benefits

  7. Isotopic Effects on Covalent Bond Confined in a Penetrable Sphere.

    PubMed

    Sarsa, Antonio; Alcaraz-Pelegrina, José M; Le Sech, Claude

    2015-11-12

    A model of confinement of the covalent bond by a finite potential beyond the Born-Oppenheimer approximation is presented. A two-electron molecule is located at the center of a penetrable spherical cavity. The Schrödinger equation has been solved by using the diffusion Monte Carlo method. Total energies, internuclear distances, and vibrational frequencies of the confined molecular system have been obtained. Even for confining potentials of a few electronvolts, a noticeable increase in the bond energy and the nuclear vibrational frequency is observed, and the internuclear distance is lowered. The gap between the zero point energy of different molecular isotopes increases with confinement. The confinement of the electron pair might play a role in chemical reactivity, providing an alternative explanation for the tunnel effect, when large values of primary kinetic isotopic effect are observed. The Swain-Schaad relation is still verified when confinement changes the zero point energy. A semiquantitative illustration is proposed using the data relative to an hydrogen transfer involving a C-H cleavage catalyzed by the bovine serum amine oxidase. Changes on the confining conditions, corresponding to a confinement/deconfinement process, result in a significant decrease in the activation energy of the chemical transformation. It is proposed that confinement/deconfinement of the electron-pair bonding by external electrostatic forces inside the active pocket of an enzyme could be one of the basic mechanisms of the enzyme catalysis. PMID:26484576

  8. 12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems

    SciTech Connect

    Berk, Herbert L.; Breizman, Boris N.

    2014-02-21

    The 12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems took place in Austin, Texas (7–11 September 2011). This meeting was organized jointly with the 5th IAEA Technical Meeting on Theory of Plasma Instabilities (5–7 September 2011). The two meetings shared one day (7 September 2011) with presentations relevant to both groups. Some of the work reported at these meetings was then published in a special issue of Nuclear Fusion [Nucl. Fusion 52 (2012)]. Summaries of the Energetic Particle Conference presentations were given by Kazuo Toi and Boris Breizman. They respectively discussed the experimental and theoretical progress presented at the meeting. Highlights of this meeting include the tremendous progress that has been achieved in the development of diagnostics that enables the ‘viewing’ of internal fluctuations and allows comparison with theoretical predictions, as demonstrated, for example, in the talks of P. Lauber and M. Osakabe. The need and development of hardened diagnostics in the severe radiation environment, such as those that will exist in ITER, was discussed in the talks of V. Kiptily and V.A. Kazakhov. In theoretical studies, much of the effort is focused on nonlinear phenomena. For example, detailed comparison of theory and experiment on D-III-D on the n = 0 geodesic mode was reported in separate papers by R. Nazikian and G. Fu. A large number of theoretical papers were presented on wave chirping including a paper by B.N. Breizman, which notes that wave chirping from a single frequency may emanate continuously once marginal stability conditions have been established. Another area of wide interest was the detailed study of alpha orbits in a burning plasma, where losses can come from symmetry breaking due to finite coil number or magnetic field imperfections introduced by diagnostic or test modules. An important area of development, covered by M.A. Hole and D.A. Spong, is concerned with the self

  9. Confined iron nanowires enhance the catalytic activity of carbon nanotubes in the aerobic oxidation of cyclohexane.

    PubMed

    Yang, Xixian; Yu, Hao; Peng, Feng; Wang, Hongjuan

    2012-07-01

    Inside job: New applications of carbon materials pave the way towards greener chemical syntheses. The encapsulation of metallic Fe within CNTs improves electron transfer between the metal and the CNTs. The resulting material offers a high catalytic activity and easy magnetic separation of catalyst in the heterogeneous selective oxidation of cyclohexane. PMID:22488987

  10. Confinement effects of polymers in porous glasses

    NASA Astrophysics Data System (ADS)

    Crupi, V.; Majolino, D.; Migliardo, P.; Venuti, V.

    1998-07-01

    Recently, confinement effects on dynamical properties of liquids inside restricted volumes have been extensively studied, either from a theoretical or technological point of view, thanks to the large possibility of industrial applications (building of optical switches, membrane separation, catalysis). We performed depolarized light scattering measurements on propylene glycol (PG) and its oligomers poly(propylene glycols) (PPG) having different molecular weights ( Mw, 425, 725 and 4000 Da), in the bulk state and confined in a silica glass having 25 Å pores. Mainly, two relevant effects are responsible for the dynamical response of liquids that diffuse and reorient in a confined geometry: (a) the 'physical traps', related to both dead-end groups and the tortuosity of the percolated channels for diffusion; and (b) the 'chemical traps', related to the degree of the absorption of molecules on the active surface sites. Hence, by comparing the behaviour of bulk polymers with confined polymers we were able to analyse the confinement influence on the molecular mobility of hydrogen-bonded liquids with different steric hindrance. The experimental results showed a frustration of molecular mobility in the confined samples owing to chemical and physical traps whose main role was highlighted thanks to the opportunity to substitute the active silanol groups (SiOH) in the inner surfaces with the non-active groups in the surfaces (treatment with methanol). In particular, we found that, in the case of low molecular weight samples, the relevant retardation process is connected to the chemical traps while for long chain polymers the physical traps play the main role. Further, the fitting procedure provided a distribution of relaxation times in the bulk systems and in short chain systems when confined in modified glass showing, in particular in the first case, that the distribution of relaxation times increases with polymers weights, occurrence related to a variety of molecular

  11. Absence of Lymphatic Vessels in PCNSL May Contribute to Confinement of Tumor Cells to the Central Nervous System.

    PubMed

    Deckert, Martina; Brunn, Anna; Montesinos-Rongen, Manuel; Siebert, Reiner

    2016-06-01

    Primary central nervous system (CNS) lymphoma (PCNSL) is a mature lymphoma of the diffuse large B-cell lymphoma (DLBCL) type confined to the CNS. Despite cytomorphological similarities between PCNSL and systemic DLBCL, molecular differences between both entities have been identified. The exclusively topographical restriction of PCNSL to the CNS is an unexplained mystery. To address the question of whether the unique lymphatic drainage system of the CNS, which differs from that of other organs, may play a role for this peculiar behavior, we investigated a series of 20 PCNSLs for the presence of lymphatic vessels by immunohistochemistry for Lyve-1, podoplanin, and Prox-1 expression. All PCNSLs lacked lymphatic vessels and, in this regard, were similar to 20 glioblastoma multiforme samples. In contrast to these tumors, all of which were located in the deep brain parenchyma, dural and meningeal DLBCL harbored lymphatic vessels that expressed Lyve-1 (3/8 tumors), podoplanin (5/8 tumors), and Prox-1 (5/8 tumors) in areas where the tumors had invaded the fibrous tissue of the dura. These data indicate that local topographical characteristics of the specific lymphatic drainage system may contribute to confinement of the tumor cells in PCNSL and malignant gliomas. PMID:27142645

  12. Characterization of impurity confinement on Alcator C-Mod using a multi-pulse laser blow-off system.

    PubMed

    Howard, N T; Greenwald, M; Rice, J E

    2011-03-01

    A new laser blow-off system for use in impurity transport studies on Alcator C-Mod was developed and installed for the 2009 run campaign. Its design included capabilities for multiple impurity injections during a single plasma pulse and remote manipulation of the ablated spot size. The system uses a 0.68 J, Nd:YAG laser operating at up to 10 Hz coupled with the fast beam steering via a 2D piezoelectric mirror mount able to move spot locations in the 100 ms between laser pulses and a remote controllable optical train that allow ablated spot sizes to vary from ∼0.5 to 7 mm. The ability to ablate a wide range in target Z along with Alcator C-Mod's extensive diagnostic capabilities (soft x-ray, vacuum ultraviolet (VUV), charge exchange spectroscopy, etc.) allows for detailed studies of the impurity transport dependencies and mechanisms. This system has demonstrated the achievement of all its design goals including the ability for non-perturbative operation allowing for insight into underlying impurity transport processes. A detailed overview of the laser blow-off system and initial results of operation are presented. This includes an investigation into the characterization of impurity confinement in the I-mode confinement regime recently investigated on C-Mod. PMID:21456742

  13. Characterization of impurity confinement on Alcator C-Mod using a multi-pulse laser blow-off system

    SciTech Connect

    Howard, N. T.; Greenwald, M.; Rice, J. E.

    2011-03-15

    A new laser blow-off system for use in impurity transport studies on Alcator C-Mod was developed and installed for the 2009 run campaign. Its design included capabilities for multiple impurity injections during a single plasma pulse and remote manipulation of the ablated spot size. The system uses a 0.68 J, Nd:YAG laser operating at up to 10 Hz coupled with the fast beam steering via a 2D piezoelectric mirror mount able to move spot locations in the 100 ms between laser pulses and a remote controllable optical train that allow ablated spot sizes to vary from {approx}0.5 to 7 mm. The ability to ablate a wide range in target Z along with Alcator C-Mod's extensive diagnostic capabilities (soft x-ray, vacuum ultraviolet (VUV), charge exchange spectroscopy, etc.) allows for detailed studies of the impurity transport dependencies and mechanisms. This system has demonstrated the achievement of all its design goals including the ability for non-perturbative operation allowing for insight into underlying impurity transport processes. A detailed overview of the laser blow-off system and initial results of operation are presented. This includes an investigation into the characterization of impurity confinement in the I-mode confinement regime recently investigated on C-Mod.

  14. Development of an NDA system for high-level waste from the Chernobyl new safe confinement construction site

    SciTech Connect

    Lee, Sang-yoon; Browne, Michael C; Rael, Carlos D; Carroll, Colin J; Sunshine, Alexander; Novikov, Alexander; Lebedev, Evgeny

    2010-01-01

    In early 2009, preliminary excavation work has begun in preparation for the construction of the New Safe Confinement (NSC) at the Chernobyl Nuclear Power Plant (ChNPP) in Ukraine. The NSC is the structure that will replace the present containment structure and will confine the radioactive remains of the ChNPP Unit-4 reactor for the next 100 years. It is expected that special nuclear material (SNM) that was ejected from the Unit-4 reactor during the accident in 1986 could be uncovered and would therefore need to be safeguarded. ChNPP requested the assistance of the United States Department of Energy/National Nuclear Security Administration (NNSA) with developing a new non-destructive assay (NDA) system that is capable of assaying radioactive debris stored in 55-gallon drums. The design of the system has to be tailored to the unique circumstances and work processes at the NSC construction site and the ChNPP. This paper describes the Chernobyl Drum Assay System (CDAS), the solution devised by Los Alamos National Laboratory, Sonalysts Inc., and the ChNPP, under NNSA's International Safeguards and Engagement Program (INSEP). The neutron counter measures the spontaneous fission neutrons from the {sup 238}U, {sup 240}Pu, {sup 244}Cm in a waste drum and estimates the mass contents of the SNMs in the drum by using of isotopic compositions determined by fuel burnup. The preliminary evaluation on overall measurement uncertainty shows that the system meets design performance requirements imposed by the facility.

  15. Neutron activation analysis system

    DOEpatents

    Taylor, M.C.; Rhodes, J.R.

    1973-12-25

    A neutron activation analysis system for monitoring a generally fluid media, such as slurries, solutions, and fluidized powders, including two separate conduit loops for circulating fluid samples within the range of radiation sources and detectors is described. Associated with the first loop is a neutron source that emits s high flux of slow and thermal neutrons. The second loop employs a fast neutron source, the flux from which is substantially free of thermal neutrons. Adjacent to both loops are gamma counters for spectrographic determination of the fluid constituents. Other gsmma sources and detectors are arranged across a portion of each loop for deterMining the fluid density. (Official Gazette)

  16. Fusion, magnetic confinement

    SciTech Connect

    Berk, H.L.

    1992-08-06

    An overview is presented of the principles of magnetic confinement of plasmas for the purpose of achieving controlled fusion conditions. Sec. 1 discusses the different nuclear fusion reactions which can be exploited in prospective fusion reactors and explains why special technologies need to be developed for the supply of tritium or {sup 3}He, the probable fuels. In Sec. 2 the Lawson condition, a criterion that is a measure of the quality of confinement relative to achieving fusion conditions, is explained. In Sec. 3 fluid equations are used to describe plasma confinement. Specific confinement configurations are considered. In Sec. 4 the orbits of particle sin magneti and electric fields are discussed. In Sec. 5 stability considerations are discussed. It is noted that confinement systems usually need to satisfy stability constraints imposed by ideal magnetohydrodynamic (MHD) theory. The paper culminates with a summary of experimental progress in magnetic confinement. Present experiments in tokamaks have reached the point that the conditions necessary to achieve fusion are being satisfied.

  17. The behavior of electrons, their correlations, and their response to transverse fields in confined systems

    NASA Astrophysics Data System (ADS)

    Choe, Woosoon

    1999-11-01

    Chapter one gives general introductions for quantum dots (QD). Chapter two studies two-dimensional (2D) QD-helium with magnetic fields ( B) by various theoretical approaches, focusing on the correlation effects. The eigenenergies and eigenfunctions are found from exact, variational, perturbational, quasi-classical (WKB) calculations, and their behaviors are studied as the confinement, electron-electron interaction, and B vary. The variational calculation reveals a possible existence of two different physical regimes. The WKB calculation reveals new, unexpected features of electron correlations, enabling the double-parabola, single-parabola approximations in the WKB regime. New spin-angular momentum-transitions with increasing interaction (or with decreasing confinement) at finite B, are found and discussed. A 3D QD-helium at B = 0 is studied and compared with the 2D one. Chapter three studies a three-electron-2D-QD with B by the electronic molecule model, arguing that when the confinement is weak enough, the electron motions in QD are well-described quasi-classically, rather than by the conventional atomic picture. The total Hamiltonian is diagonalized by normal modes, using the group theory, to give full energy spectrum and eigenfunctions analytically. The total wavefunctions, including the spin part, are anti-symmetrized by purely group theoretical arguments. Only particular values of the total angular momentum are shown to be allowed for a given spin state. The physical origin of the magic number is identified. The model is justified self-consistently. Chapter four calculates, using a perturbative-variational method, the ground state energies of D0, D - centers and binding energy of a D - center in a quantum well with B, as a function of B and a well width. Chapter five calculates, first, the wave vector q and frequency o-dependent transverse dielectric function, eTq,w for a bulk semiconductor, showing that the reported calculations [61, 71] of eLq,0 and eTq,0

  18. European Neutron Activation System.

    2013-01-11

    Version 03 EASY-2010 (European Activation System) consists of a wide range of codes, data and documentation all aimed at satisfying the objective of calculating the response of materials irradiated in a neutron flux. The main difference from the previous version is the upper energy limit, which has increased from 20 to 60 MeV. It is designed to investigate both fusion devices and accelerator based materials test facilities that will act as intense sources of high-energymore » neutrons causing significant activation of the surrounding materials. The very general nature of the calculational method and the data libraries means that it is applicable (with some reservations) to all situations (e.g. fission reactors or neutron sources) where materials are exposed to neutrons below 60 MeV. EASY can be divided into two parts: data and code development tools and user tools and data. The former are required to develop the latter, but EASY users only need to be able to use the inventory code FISPACT and be aware of the contents of the EAF library (the data source). The complete EASY package contains the FISPACT-2007 inventory code, the EAF-2003, EAF-2005, EAF-2007 and EAF-2010 libraries, and the EASY User Interface for the Window version. The activation package EASY-2010 is the result of significant development to extend the upper energy range from 20 to 60 MeV so that it is capable of being used for IFMIF calculations. The EAF-2010 library contains 66,256 reactions, almost five times more than in EAF-2003 (12,617). Deuteron-induced and proton-induced cross section libraries are also included, and can be used with EASY to enable calculations of the activation due to deuterons and proton [2].« less

  19. Stability of D brane-anti D brane systems in confining gauge theories

    NASA Astrophysics Data System (ADS)

    Ghoroku, Kazuo; Nakamura, Akihiro; Toyoda, Fumihiko

    2011-01-01

    We study the stability of a special form of D brane embedding which is regarded as a bound state of D n and anti-D n brane embedded in a 10D supergravity background which is dual to a confining gauge theory. For D5 branes with U(1) flux, their bound-state configuration can be regarded as the baryonium vertex. For D branes of n=6 and 8 without the U(1) flux, their bound states have been used to introduce flavor quarks in the dual supersymmetric Yang-Mills theory. In any case, it would be important to ensure that they are free from tachyon instability. For all these cases, we could show their stability with respect to this point.

  20. Quantum propagation and confinement in 1D systems using the transfer-matrix method

    NASA Astrophysics Data System (ADS)

    Pujol, Olivier; Carles, Robert; Pérez, José-Philippe

    2014-05-01

    The aim of this article is to provide some Matlab scripts to the teaching community in quantum physics. The scripts are based on the transfer-matrix formalism and offer a very efficient and versatile tool to solve problems of a physical object (electron, proton, neutron, etc) with one-dimensional (1D) stationary potential energy. Resonant tunnelling through a multiple-barrier or confinement in wells of various shapes is particularly analysed. The results are quantitatively discussed with semiconductor heterostructures, harmonic and anharmonic molecular vibrations, or neutrons in a gravity field. Scripts and other examples (hydrogen-like ions and transmission by a smooth variation of potential energy) are available freely at http://www-loa.univ-lille1.fr/˜pujol in three languages: English, French and Spanish.

  1. Porous capsules with a large number of active sites: nucleation/growth under confined conditions.

    PubMed

    Garai, Somenath; Rubčić, Mirta; Bögge, Hartmut; Gouzerh, Pierre; Müller, Achim

    2015-03-01

    This work deals with the generation of large numbers of active sites and with ensuing nucleation/ growth processes on the inside wall of the cavity of porous nanocapsules of the type (pentagon)12(linker)30≡{(Mo(VI))Mo(VI)5}12{Mo(V)2(ligand)}30. A first example refers to sulfur dioxide capture through displacement of acetate ligands, while the grafted sulfite ligands are able to trap {MoO3H}(+) units thereby forming unusual {(O2SO)3MoO3H}(5-) assemblies. A second example relates to the generation of open coordination sites through release of carbon dioxide upon mild acidification of a carbonate-type capsule. When the reaction is performed in the presence of heptamolybdate ions, MoO4(2-) ions enter the cavity where they bind to the inside wall while forming new types of polyoxomolybdate architectures, thereby extending the molybdenum oxide skeleton of the capsule. Parallels can be drawn with Mo-storage proteins and supported MoO3 catalysts, making the results relevant to molybdenum biochemistry and to catalysis. PMID:25653204

  2. Circularly confined microswimmers exhibit multiple global patterns.

    PubMed

    Tsang, Alan Cheng Hou; Kanso, Eva

    2015-04-01

    Geometric confinement plays an important role in the dynamics of natural and synthetic microswimmers from bacterial cells to self-propelled particles in high-throughput microfluidic devices. However, little is known about the effects of geometric confinement on the emergent global patterns in such self-propelled systems. Recent experiments on bacterial cells report that, depending on the cell concentration, cells either spontaneously organize into vortical motion in thin cylindrical and spherical droplets or aggregate at the inner boundary of the droplets. Our goal in this paper is to investigate, in the context of an idealized physical model, the interplay between geometric confinement and level of flagellar activity on the emergent collective patterns. We show that decreasing flagellar activity induces a hydrodynamically triggered transition in confined microswimmers from swirling to global circulation (vortex) to boundary aggregation and clustering. These results highlight that the complex interplay between confinement, flagellar activity, and hydrodynamic flows in concentrated suspensions of microswimmers could lead to a plethora of global patterns that are difficult to predict from geometric consideration alone. PMID:25974581

  3. Circularly confined microswimmers exhibit multiple global patterns

    NASA Astrophysics Data System (ADS)

    Tsang, Alan Cheng Hou; Kanso, Eva

    2015-04-01

    Geometric confinement plays an important role in the dynamics of natural and synthetic microswimmers from bacterial cells to self-propelled particles in high-throughput microfluidic devices. However, little is known about the effects of geometric confinement on the emergent global patterns in such self-propelled systems. Recent experiments on bacterial cells report that, depending on the cell concentration, cells either spontaneously organize into vortical motion in thin cylindrical and spherical droplets or aggregate at the inner boundary of the droplets. Our goal in this paper is to investigate, in the context of an idealized physical model, the interplay between geometric confinement and level of flagellar activity on the emergent collective patterns. We show that decreasing flagellar activity induces a hydrodynamically triggered transition in confined microswimmers from swirling to global circulation (vortex) to boundary aggregation and clustering. These results highlight that the complex interplay between confinement, flagellar activity, and hydrodynamic flows in concentrated suspensions of microswimmers could lead to a plethora of global patterns that are difficult to predict from geometric consideration alone.

  4. Transition metal catalysis in confined spaces.

    PubMed

    Leenders, Stefan H A M; Gramage-Doria, Rafael; de Bruin, Bas; Reek, Joost N H

    2015-01-21

    Transition metal catalysis plays an important role in both industry and in academia where selectivity, activity and stability are crucial parameters to control. Next to changing the structure of the ligand, introducing a confined space as a second coordination sphere around a metal catalyst has recently been shown to be a viable method to induce new selectivity and activity in transition metal catalysis. In this review we focus on supramolecular strategies to encapsulate transition metal complexes with the aim of controlling the selectivity via the second coordination sphere. As we will discuss, catalyst confinement can result in selective processes that are impossible or difficult to achieve by traditional methods. We will describe the template-ligand approach as well as the host-guest approach to arrive at such supramolecular systems and discuss how the performance of the catalyst is enhanced by confining it in a molecular container. PMID:25340992

  5. Fractional Quantum Hall Effect at ν = 1 / 2 in Hole Systems Confined to GaAs Wide Quantum Wells

    NASA Astrophysics Data System (ADS)

    Hasdemir, Sukret; Liu, Yang; Graninger, Aurelius; Shayegan, Mansour; Pfeiffer, Loren; West, Ken; Baldwin, Kirk; Winkler, Roland

    2014-03-01

    We observe fractional quantum Hall effect (FQHE) at the even-denominator Landau level filling factor ν = 1 / 2 in two-dimensional hole systems confined to GaAs quantum wells of width 30 to 50 nm and having bilayer-like charge distributions. The ν = 1 / 2 FQHE is stable when the charge distribution is symmetric and only in a range of intermediate densities, qualitatively similar to what is seen in two-dimensional electron systems confined to approximately twice wider GaAs quantum wells. Despite the complexity of the hole Landau level structure, originating from the coexistence and mixing of the heavy- and light-hole states, we find the hole ν = 1 / 2 FQHE to be consistent with a two-component, Halperin-Laughlin (Ψ331) state. We acknowledge support through the DOE BES (DE-FG02-00-ER45841) for measurements, and the Gordon and Betty Moore Foundation (Grant GBMF2719), Keck Foundation, and the NSF (DMR-0904117, DMR-1305691 and MRSEC DMR-0819860) for sample fabrication. Work at Arg.

  6. Smoothed particle hydrodynamics: Applications to migration of radionuclides in confined aqueous systems.

    PubMed

    Mayoral-Villa, Estela; Alvarado-Rodríguez, Carlos E; Klapp, Jaime; Gómez-Gesteira, Moncho; Sigalotti, Leonardo Di G

    2016-04-01

    A smoothed particle hydrodynamics (SPH) model is presented for simulating the decay chain transport of radionuclides in confined aqueous solutions. The SPH formulation is based on the open-source parallel code DualSPHysics extended to solve the advective-diffusion equation for the evolution of the concentration field coupled to the fluid-dynamic equations, including the effects of radioactive decay of the tracer contaminants. The performance of the method is demonstrated for environmental engineering problems dealing with the transport of contaminants in still and flowing water. The results from a series of benchmark test calculations are described in two- and three-space dimensions, where the advection, diffusion, and radioactive decay modes are tested separately and in combined form. The accuracy of the present SPH transport model is shown by direct comparison with the analytical solutions and results from other SPH approaches. For a given problem, convergence of the SPH solution is seen to increase with decreasing particle size and spacing. PMID:26921532

  7. Smoothed particle hydrodynamics: Applications to migration of radionuclides in confined aqueous systems

    NASA Astrophysics Data System (ADS)

    Mayoral-Villa, Estela; Alvarado-Rodríguez, Carlos E.; Klapp, Jaime; Gómez-Gesteira, Moncho; Di G. Sigalotti, Leonardo

    2016-04-01

    A smoothed particle hydrodynamics (SPH) model is presented for simulating the decay chain transport of radionuclides in confined aqueous solutions. The SPH formulation is based on the open-source parallel code DualSPHysics extended to solve the advective-diffusion equation for the evolution of the concentration field coupled to the fluid-dynamic equations, including the effects of radioactive decay of the tracer contaminants. The performance of the method is demonstrated for environmental engineering problems dealing with the transport of contaminants in still and flowing water. The results from a series of benchmark test calculations are described in two- and three-space dimensions, where the advection, diffusion, and radioactive decay modes are tested separately and in combined form. The accuracy of the present SPH transport model is shown by direct comparison with the analytical solutions and results from other SPH approaches. For a given problem, convergence of the SPH solution is seen to increase with decreasing particle size and spacing.

  8. Emissive Probe Measurements in a Dual-Frequency-Confined Capacitively-Coupled-Plasma System

    NASA Astrophysics Data System (ADS)

    Linnane, Shane; Ellingboe, Albert R.

    2002-10-01

    Dual frequency confined capacitively coupled plasmas (DFC-CCP) are increasingly used in semiconductor manufacturing for dielectric etching, allowing greater (and independent) control of ion energies and ion flux on the etched substrate. The powered electrode is driven with the summation of 27MHz and 2MHz sinusoidal voltages, while the other electrode is grounded. The electrode areas are similar in size, giving an electrode aspect ratio less than 2. Because of this low aspect ratio, there are large oscillations in the plasma potential. The expectation is for sinusoidal oscillations at the higher driving frequency, due to capacitive sheaths, while a rectified oscillation is expected at the lower driving frequency.(E. Kawamura, V. Vahedi, M. A. Lieberman and C. K. Birdsall, Plasma Sources Sci. Technology. 8 (1999) R45-R64 Work Supported by EURATOM.) Measurements of rf oscillation in the plasma potential taken with a floating emissive probe will be presented. The emissive probe and circuitry allows direct realtime measurement of plasma potential oscillation at both driving frequencies and the harmonics of each, thus allowing measurement of the actual potential on the driven electrode and ion energy incident on grounded electrode.

  9. Energy transfer in finite-size exciton-phonon systems: Confinement-enhanced quantum decoherence

    NASA Astrophysics Data System (ADS)

    Pouthier, Vincent

    2012-09-01

    Based on the operatorial formulation of the perturbation theory, the exciton-phonon problem is revisited for investigating exciton-mediated energy flow in a finite-size lattice. Within this method, the exciton-phonon entanglement is taken into account through a dual dressing mechanism so that exciton and phonons are treated on an equal footing. In a marked contrast with what happens in an infinite lattice, it is shown that the dynamics of the exciton density is governed by several time scales. The density evolves coherently in the short-time limit, whereas a relaxation mechanism occurs over intermediated time scales. Consequently, in the long-time limit, the density converges toward a nearly uniform distributed equilibrium distribution. Such a behavior results from quantum decoherence that originates in the fact that the phonons evolve differently depending on the path followed by the exciton to tunnel along the lattice. Although the relaxation rate increases with the temperature and with the coupling, it decreases with the lattice size, suggesting that the decoherence is inherent to the confinement.

  10. Confining collective motion

    NASA Astrophysics Data System (ADS)

    Bartolo, Denis; Bricard, Antoine; Caussin, Jean-Baptiste; Savoie, Charles; Das, Debasish; Chepizhko, Oleskar; Peruani, Fernando; Saintillan, David

    2014-11-01

    It is well established that geometrical confinement have a significant impact on the structure and the flow properties of complex fluids. Prominent examples include the formation of topological defects in liquid crystals, and the flow instabilities of viscoelastic fluids in curved geometries. In striking contrast very little is known about the macroscopic behavior of confined active fluids. In this talk we show how to motorize plastic colloidal beads and turn them into self-propelled particles. Using microfluidic geometries we demonstrate how confinement impacts their collective motion. Combining quantitative experiments, analytical theory and numerical simulations we show how a population of motile bodies interacting via alignement and repulsive interactions self-organizes into a single heterogeneous macroscopic vortex that lives on the verge of a phase separation.

  11. Technology Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Brame, Ray; And Others

    This guide contains 43 modules of laboratory activities for technology education courses. Each module includes an instructor's resource sheet and the student laboratory activity. Instructor's resource sheets include some or all of the following elements: module number, course title, activity topic, estimated time, essential elements, objectives,…

  12. Dynamical Spin Properties of Confined Fermi and Bose Systems in the Presence of Spin-Orbit Coupling

    NASA Astrophysics Data System (ADS)

    Ambrosetti, A.; Salasnich, L.; Silvestrelli, P. L.

    2016-04-01

    Due to the recent experimental progress, tunable spin-orbit (SO) interactions represent ideal candidates for the control of polarization and dynamical spin properties in both quantum wells and cold atomic systems. A detailed understanding of spin properties in SO-coupled systems is thus a compelling prerequisite for possible novel applications or improvements in the context of spintronics and quantum computers. Here, we analyze the case of equal Rashba and Dresselhaus couplings in both homogeneous and laterally confined two-dimensional systems. Starting from the single-particle picture and subsequently introducing two-body interactions we observe that periodic spin fluctuations can be induced and maintained in the system. Through an analytical derivation, we show that the two-body interaction does not involve decoherence effects in the bosonic dimer, and, in the repulsive homogeneous Fermi gas, it may be even exploited in combination with the SO coupling to induce and tune standing currents. By further studying the effects of a harmonic lateral confinement—a particularly interesting case for Bose condensates—we evidence the possible appearance of nontrivial spin textures, whereas the further application of a small Zeeman-type interaction can be exploited to fine-tune the system's polarizability.

  13. On the Rotating Effects and the Landau-Aharonov-Casher System Subject to a Hard-Wall Confining Potential in the Cosmic String Spacetime

    NASA Astrophysics Data System (ADS)

    Bakke, K.

    2015-07-01

    The behaviour of the Landau-Aharonov-Casher system is discussed by showing a case where the external electric field cannot yield the Landau-Aharonov-Casher quantization under the influence of rotating effects in the cosmic string spacetime, but it can yield bound states solutions to the Schrödinger-Pauli equation analogous to having the Landau-Aharonov-Casher system confined to a hard-wall confining potential under the influence of rotating effects and the topology of the cosmic string spacetime (by assuming ω ρ≪1 and neglecting the effects of a gravitational self-force on the particle).

  14. Evolution of views on the structure of the ambipolar electric field in toroidal magnetic confinement systems

    SciTech Connect

    Kovrizhnykh, L. M.

    2015-12-15

    Various methods of determining the ambipolar electric field in toroidal magnetic systems (predominantly, in stellarators) and the evolution of views on this problem are discussed. Paradoxes encountered in solving this problem are analyzed, and ways of resolving them are proposed.

  15. Cell multipole method for molecular simulations in bulk and confined systems

    SciTech Connect

    Zheng, Jie; Balasundaram, Ramkumar; Gehrke, Stevin H.; Heffelfinger, Grant S.; Goddard, William A. III; Jiang, Shaoyi

    2002-08-01

    One of the bottlenecks in molecular simulations is to treat large systems involving electrostatic interactions. Computational time in conventional molecular simulation methods scales with O(N{sup 2}), where N is the number of atoms. With the emergence of the cell multipole method (CMM) and massively parallel supercomputers, simulations of 10 million atoms have been performed. In this work, the optimal hierarchy cell level and the algorithm for Taylor expansion were recommended for fast and accurate molecular dynamics (MD) simulations of three-dimensional (3D) systems. CMM was then extended to treat quasi-two-dimensional (2D) systems, which is very important for condensed matter physics problems. In addition, CMM was applied to grand canonical ensemble Monte Carlo (GCMC) simulations for both 3D and 2D systems. Under the optimal conditions, the results show that computational time is approximately linear with N for large systems, average error in total potential energy is less than {approx}1%, and RMS force is about 0.015 for 3D and 2D systems when compared with the Ewald summation.

  16. A System for Measuring Defect Induced Beam Modulation on Inertial Confinement Fusion-class Laser Optics

    SciTech Connect

    Runkel, M; Hawley-Fedder, R; Widmayer, C; Williams, W; Weinzapfel, C; Roberts, D

    2005-10-18

    A multi-wavelength laser based system has been constructed to measure defect induced beam modulation (diffraction) from ICF class laser optics. The Nd:YLF-based modulation measurement system (MMS) uses simple beam collimation and imaging to capture diffraction patterns from optical defects onto an 8-bit digital camera at 1053, 527 and 351 nm. The imaging system has a field of view of 4.5 x 2.8 mm{sup 2} and is capable of imaging any plane from 0 to 30 cm downstream from the defect. The system is calibrated using a 477 micron chromium dot on glass for which the downstream diffraction patterns were calculated numerically. Under nominal conditions the system can measure maximum peak modulations of approximately 7:1. An image division algorithm is used to calculate the peak modulation from the diffracted and empty field images after the baseline residual light background is subtracted from both. The peak modulation can then be plotted versus downstream position. The system includes a stage capable of holding optics up to 50 pounds with x and y translation of 40 cm and has been used to measure beam modulation due to solgel coating defects, surface digs on KDP crystals, lenslets in bulk fused silica and laser damage sites mitigated with CO{sub 2} lasers.

  17. A system for measuring defect induced beam modulation on inertial confinement fusion-class laser optics

    NASA Astrophysics Data System (ADS)

    Runkel, Mike; Hawley-Fedder, Ruth; Widmayer, Clay; Williams, Wade; Weinzapfel, Carolyn; Roberts, Dave

    2005-12-01

    A multi-wavelength laser based system has been constructed to measure defect induced beam modulation (diffraction) from ICF class laser optics. The Nd:YLF-based modulation measurement system (MMS) uses simple beam collimation and imaging to capture diffraction patterns from optical defects onto an 8-bit digital camera at 1053, 527 and 351 nm. The imaging system has a field of view of 4.5 x 2.8 mm2 and is capable of imaging any plane from 0 to 30 cm downstream from the defect. The system is calibrated using a 477 micron chromium dot on glass for which the downstream diffraction patterns were calculated numerically. Under nominal conditions the system can measure maximum peak modulations of approximately 7:1. An image division algorithm is used to calculate the peak modulation from the diffracted and empty field images after the baseline residual light background is subtracted from both. The peak modulation can then be plotted versus downstream position. The system includes a stage capable of holding optics up to 50 pounds with x and y translation of 40 cm and has been used to measure beam modulation due to solgel coating defects, surface digs on KDP crystals, lenslets in bulk fused silica and laser damage sites mitigated with CO2 lasers.

  18. Arterial branching within the confines of fractal L-system formalism.

    PubMed

    Zamir, M

    2001-09-01

    Parametric Lindenmayer systems (L-systems) are formulated to generate branching tree structures that can incorporate the physiological laws of arterial branching. By construction, the generated trees are de facto fractal structures, and with appropriate choice of parameters, they can be made to exhibit some of the branching patterns of arterial trees, particularly those with a preponderant value of the asymmetry ratio. The question of whether arterial trees in general have these fractal characteristics is examined by comparison of pattern with vasculature from the cardiovascular system. The results suggest that parametric L-systems can be used to produce fractal tree structures but not with the variability in branching parameters observed in arterial trees. These parameters include the asymmetry ratio, the area ratio, branch diameters, and branching angles. The key issue is that the source of variability in these parameters is not known and, hence, it cannot be accurately reproduced in a model. L-systems with a random choice of parameters can be made to mimic some of the observed variability, but the legitimacy of that choice is not clear. PMID:11524457

  19. Portable active interrogation system.

    SciTech Connect

    Moss, C. E.; Brener, M. W.; Hollas, C. L.; Myers, W. L.

    2004-01-01

    The system consists of a pulsed DT neutron generator (5 x 10{sup 7} n/s) and a portable but high intrinsic efficiency, custom-designed, polyethylene-moderated {sup 3}He neutron detector. A multichannel scaler card in a ruggedized laptop computer acquires the data. A user-friendly LabVIEW program analyzes and displays the data. The program displays a warning message when highly enriched uranium or any other fissionable materials is detected at a specified number of sigmas above background in the delayed region between pulses. This report describes the system and gives examples of the response of the system to highly enriched uranium and some other fissionable materials, at several distances and with various shielding materials.

  20. Trap-size scaling in confined-particle systems at quantum transitions

    SciTech Connect

    Campostrini, Massimo; Vicari, Ettore

    2010-02-15

    We develop a trap-size scaling theory for trapped particle systems at quantum transitions. As a theoretical laboratory, we consider a quantum XY chain in an external transverse field acting as a trap for the spinless fermions of its quadratic Hamiltonian representation. We discuss trap-size scaling at the Mott insulator to superfluid transition in the Bose-Hubbard model. We present exact and accurate numerical results for the XY chain and for the low-density Mott transition in the hard-core limit of the one-dimensional Bose-Hubbard model. Our results are relevant for systems of cold atomic gases in optical lattices.

  1. Excitation of flute waves by an ion beam in an open confinement system

    SciTech Connect

    Stupakov, G.V.

    1988-04-01

    This paper analyzes the electrostatic instability driven by a fast ion beam in a low-..beta.. plasma in a mirror system as the result of a resonance between the wave and the longitudinal bounces of ions between the mirrors. The frequency of this instability is close to the ion bounce frequency, and its growth rate is several times low than that of the flute instability. This electrostatic instability is characteristic of beams with a small angular spread and is sensitive to the magnetic field profile in the mirror system.

  2. Digital Lock-In Amplifier Based Ground Loop Monitoring System for Magnetically Confined Plasma Devices

    NASA Astrophysics Data System (ADS)

    Connelly, Timothy; Schneider, Hans

    2004-11-01

    The National Spherical Torus Experiment (NSTX) at the Princeton Plasma Physics Lab (PPPL) currently uses an analog lock-in amplifier in its Ground Fault Monitor (GFM) system for ground loop detection. For the forthcoming National Compact Stellerator Experiment, a new GFM is currently under development. The current GFM for NSTX is a heritage system originally designed for the Tokamak Fusion Test Reactor and has since had significant enhancements of increased Loop Fault Sensitivity, improved operator interface, and data archiving. A digital GFM may further increase operational performance while adding new features. The digital system would run on a Personal Computer with National Instruments data acquisition hardware along with the tightly integrated LabVIEW software. LabVIEW's Lock-In Amplifier and Digital Signal Processing building blocks saved a significant amount of development time. The primary goal of the research was to determine the feasibility of a LabVIEW based GFM on a bench test setup and, time permitting, in-situ testing on NSTX. Secondary goals include: evaluation of performance of digital versus existing analog system, assessing the use of software implementations of filters, spectral analysis of received signals and data archiving.

  3. Confined One Dimensional Harmonic Oscillator as a Two-Mode System

    SciTech Connect

    Gueorguiev, V G; Rau, A P; Draayer, J P

    2005-07-11

    The one-dimensional harmonic oscillator in a box problem is possibly the simplest example of a two-mode system. This system has two exactly solvable limits, the harmonic oscillator and a particle in a (one-dimensional) box. Each of the two limits has a characteristic spectral structure describing the two different excitation modes of the system. Near each of these limits, one can use perturbation theory to achieve an accurate description of the eigenstates. Away from the exact limits, however, one has to carry out a matrix diagonalization because the basis-state mixing that occurs is typically too large to be reproduced in any other way. An alternative to casting the problem in terms of one or the other basis set consists of using an ''oblique'' basis that uses both sets. Through a study of this alternative in this one-dimensional problem, we are able to illustrate practical solutions and infer the applicability of the concept for more complex systems, such as in the study of complex nuclei where oblique-basis calculations have been successful.

  4. Asymptotic equivalence of the shell-model and local-density descriptions of Coulombic systems confined by radially symmetric potentials in two and three dimensions.

    PubMed

    Cioslowski, Jerzy; Albin, Joanna

    2013-09-21

    Asymptotic equivalence of the shell-model and local-density (LDA) descriptions of Coulombic systems confined by radially symmetric potentials in two and three dimensions is demonstrated. Tight upper bounds to the numerical constants that enter the LDA expressions for the Madelung energy are derived and found to differ by less than 0.5% from the previously known approximate values. Thanks to the variational nature of the shell-model approximate energies, asymptotic expressions for other properties, such as mean radial positions of the particles and number densities, are also obtained. A conjecture that generalizes the present results to confining potentials with arbitrary symmetries is formulated. PMID:24070281

  5. Does the spatial confinement influence the electric properties and cooperative effects of the hydrogen bonded systems? HCN chains as a case study

    NASA Astrophysics Data System (ADS)

    Roztoczyńska, Agnieszka; Kozłowska, Justyna; Lipkowski, Paweł; Bartkowiak, Wojciech

    2014-07-01

    In this Letter the impact of orbital compression on the energetic and electric properties as well as cooperative effects in the hydrogen bonded systems was investigated. The model (HCN)n chains, with n = 2-5, were chosen as a case study. The effect of spatial restriction was modeled by the harmonic oscillator potential. Moreover, changes in the structural parameters in the presence of model confining potential were also analyzed. All calculations were performed using the MP2 method. The obtained results demonstrated inter alia that the spatial confinement significantly influences the analyzed properties.

  6. Confined helium on Lagrange meshes.

    PubMed

    Baye, D; Dohet-Eraly, J

    2015-12-21

    The Lagrange-mesh method has the simplicity of a calculation on a mesh and can have the accuracy of a variational method. It is applied to the study of a confined helium atom. Two types of confinement are considered. Soft confinements by potentials are studied in perimetric coordinates. Hard confinement in impenetrable spherical cavities is studied in a system of rescaled perimetric coordinates varying in [0,1] intervals. Energies and mean values of the distances between electrons and between an electron and the helium nucleus are calculated. A high accuracy of 11 to 15 significant figures is obtained with small computing times. Pressures acting on the confined atom are also computed. For sphere radii smaller than 1, their relative accuracies are better than 10(-10). For larger radii up to 10, they progressively decrease to 10(-3), still improving the best literature results. PMID:25732054

  7. Confined Phase Envelope of Gas-Condensate Systems in Shale Rocks

    NASA Astrophysics Data System (ADS)

    Nagy, Stanislaw; Siemek, Jakub

    2014-12-01

    Natural gas from shales (NGS) and from tight rocks are one of the most important fossil energy resource in this and next decade. Significant increase in gas consumption, in all world regions, will be marked in the energy sector. The exploration of unconventional natural gas & oil reservoirs has been discussed recently in many conferences. This paper describes the complex phenomena related to the impact of adsorption and capillary condensation of gas-condensate systems in nanopores. New two phase saturation model and new algorithm for search capillary condensation area is discussed. The algorithm is based on the Modified Tangent Plane Criterion for Capillary Condensation (MTPCCC) is presented. The examples of shift of phase envelopes are presented for selected composition of gas-condensate systems. Gaz ziemny z łupków (NGS) oraz z ze złóż niskoprzepuszczalnych (typu `tight') staje się jednym z najważniejszych zasobów paliw kopalnych, w tym i następnym dziesięcioleciu. Znaczący wzrost zużycia gazu we wszystkich regionach świata zaznacza się głównie w sektorze energetycznym. Rozpoznawanie niekonwencjonalnych złóż gazu ziemnego i ropy naftowej w ostatnim czasie jest omawiane w wielu konferencjach. Niniejszy artykuł opisuje złożone zjawiska związane z wpływem adsorpcji i kapilarnej kondensacji w nanoporach w złożach gazowo-kondensatowych. Pokazano nowy dwufazowy model równowagowy dwufazowy i nowy algorytm wyznaczania krzywej nasycenia w obszarze kondensacji kapilarnej. Algorytm bazuje na kryterium zmodyfikowanym płaszczyzny stycznej dla kapilarnej kondensacji (MTPCCC). Przykłady zmiany krzywych nasycenia są przedstawiane w wybranym składzie systemów gazowo- kondensatowych

  8. Tools for Predicting Optical Damage on Inertial Confinement Fusion-Class Laser Systems

    SciTech Connect

    Nostrand, M C; Carr, C W; Liao, Z M; Honig, J; Spaeth, M L; Manes, K R; Johnson, M A; Adams, J J; Cross, D A; Negres, R A; Widmayer, C C; Williams, W H; Matthews, M J; Jancaitis, K S; Kegelmeyer, L M

    2010-12-20

    Operating a fusion-class laser to its full potential requires a balance of operating constraints. On the one hand, the total laser energy delivered must be high enough to give an acceptable probability for ignition success. On the other hand, the laser-induced optical damage levels must be low enough to be acceptably handled with the available infrastructure and budget for optics recycle. Our research goal was to develop the models, database structures, and algorithmic tools (which we collectively refer to as ''Loop Tools'') needed to successfully maintain this balance. Predictive models are needed to plan for and manage the impact of shot campaigns from proposal, to shot, and beyond, covering a time span of years. The cost of a proposed shot campaign must be determined from these models, and governance boards must decide, based on predictions, whether to incorporate a given campaign into the facility shot plan based upon available resources. Predictive models are often built on damage ''rules'' derived from small beam damage tests on small optics. These off-line studies vary the energy, pulse-shape and wavelength in order to understand how these variables influence the initiation of damage sites and how initiated damage sites can grow upon further exposure to UV light. It is essential to test these damage ''rules'' on full-scale optics exposed to the complex conditions of an integrated ICF-class laser system. Furthermore, monitoring damage of optics on an ICF-class laser system can help refine damage rules and aid in the development of new rules. Finally, we need to develop the algorithms and data base management tools for implementing these rules in the Loop Tools. The following highlights progress in the development of the loop tools and their implementation.

  9. Topological confinement and superconductivity

    SciTech Connect

    Al-hassanieh, Dhaled A; Batista, Cristian D

    2008-01-01

    We derive a Kondo Lattice model with a correlated conduction band from a two-band Hubbard Hamiltonian. This mapping allows us to describe the emergence of a robust pairing mechanism in a model that only contains repulsive interactions. The mechanism is due to topological confinement and results from the interplay between antiferromagnetism and delocalization. By using Density-Matrix-Renormalization-Group (DMRG) we demonstrate that this mechanism leads to dominant superconducting correlations in aID-system.

  10. Classical confined particles

    NASA Technical Reports Server (NTRS)

    Horzela, Andrzej; Kapuscik, Edward

    1993-01-01

    An alternative picture of classical many body mechanics is proposed. In this picture particles possess individual kinematics but are deprived from individual dynamics. Dynamics exists only for the many particle system as a whole. The theory is complete and allows to determine the trajectories of each particle. It is proposed to use our picture as a classical prototype for a realistic theory of confined particles.

  11. A particle-in-mesh method for Brownian Dynamics simulation of many-particle systems with hydrodynamics interactions in a confined geometry

    NASA Astrophysics Data System (ADS)

    Zhao, Xujun; Hernandez-Ortiz, Juan; Karpeyev, Dmitry; de Pablo, Juan; Smith, Barry

    In this work, we present an efficient parallel particle-in-mesh method for Brownian Dynamics simulations of many-particle systems confined in micro- and nano-fluidic devices. A general geometry Ewald-like method (GGEM) combined with finite element method is used to account for the hydrodynamic interaction. A fast parallel Krylov-type iterative solver with hybrid preconditioning techniques is developed for solving the large sparse systems of equations arising from finite element discretization of the Stokes equations. In addition, the current computer code is developed based on PETSc, a scalable library of numerical algorithms developed at Argonne, SLEPc - Scalable Library for Eigenvalue Problem Computations, and libMesh, a finite element library for numerical solution of PDEs built on top of PETSc, which allows for direct simulation of large scale systems with arbitrary confined geometries. This scheme is applied to Brownian dynamics simulations of flowing confined polymer solutions and colloidal dispersions in micro-fluid channels. The effects of hydrodynamics interactions and geometric confinement on the migration phenomena are illustrated.

  12. Contact line motion in confined liquid-gas systems: Slip versus phase transition.

    PubMed

    Xu, Xinpeng; Qian, Tiezheng

    2010-11-28

    In two-phase flows, the interface intervening between the two fluid phases intersects the solid wall at the contact line. A classical problem in continuum fluid mechanics is the incompatibility between the moving contact line and the no-slip boundary condition, as the latter leads to a nonintegrable stress singularity. Recently, various diffuse-interface models have been proposed to explain the contact line motion using mechanisms missing from the sharp-interface treatments in fluid mechanics. In one-component two-phase (liquid-gas) systems, the contact line can move through the mass transport across the interface while in two-component (binary) fluids, the contact line can move through diffusive transport across the interface. While these mechanisms alone suffice to remove the stress singularity, the role of fluid slip at solid surface needs to be taken into account as well. In this paper, we apply the diffuse-interface modeling to the study of contact line motion in one-component liquid-gas systems, with the fluid slip fully taken into account. The dynamic van der Waals theory has been presented for one-component fluids, capable of describing the two-phase hydrodynamics involving the liquid-gas transition [A. Onuki, Phys. Rev. E 75, 036304 (2007)]. This theory assumes the local equilibrium condition at the solid surface for density and also the no-slip boundary condition for velocity. We use its hydrodynamic equations to describe the continuum hydrodynamics in the bulk region and derive the more general boundary conditions by introducing additional dissipative processes at the fluid-solid interface. The positive definiteness of entropy production rate is the guiding principle of our derivation. Numerical simulations based on a finite-difference algorithm have been carried out to investigate the dynamic effects of the newly derived boundary conditions, showing that the contact line can move through both phase transition and slip, with their relative contributions

  13. Contact line motion in confined liquid-gas systems: Slip versus phase transition

    NASA Astrophysics Data System (ADS)

    Xu, Xinpeng; Qian, Tiezheng

    2010-11-01

    In two-phase flows, the interface intervening between the two fluid phases intersects the solid wall at the contact line. A classical problem in continuum fluid mechanics is the incompatibility between the moving contact line and the no-slip boundary condition, as the latter leads to a nonintegrable stress singularity. Recently, various diffuse-interface models have been proposed to explain the contact line motion using mechanisms missing from the sharp-interface treatments in fluid mechanics. In one-component two-phase (liquid-gas) systems, the contact line can move through the mass transport across the interface while in two-component (binary) fluids, the contact line can move through diffusive transport across the interface. While these mechanisms alone suffice to remove the stress singularity, the role of fluid slip at solid surface needs to be taken into account as well. In this paper, we apply the diffuse-interface modeling to the study of contact line motion in one-component liquid-gas systems, with the fluid slip fully taken into account. The dynamic van der Waals theory has been presented for one-component fluids, capable of describing the two-phase hydrodynamics involving the liquid-gas transition [A. Onuki, Phys. Rev. E 75, 036304 (2007)]. This theory assumes the local equilibrium condition at the solid surface for density and also the no-slip boundary condition for velocity. We use its hydrodynamic equations to describe the continuum hydrodynamics in the bulk region and derive the more general boundary conditions by introducing additional dissipative processes at the fluid-solid interface. The positive definiteness of entropy production rate is the guiding principle of our derivation. Numerical simulations based on a finite-difference algorithm have been carried out to investigate the dynamic effects of the newly derived boundary conditions, showing that the contact line can move through both phase transition and slip, with their relative contributions

  14. Sweetpotato vine management for confined food production in a space life-support system

    NASA Astrophysics Data System (ADS)

    Massa, Gioia D.; Mitchell, Cary A.

    2012-01-01

    Sweetpotato (Ipomea batatas L.) 'Whatley-Loretan' was developed for space life support by researchers at Tuskegee University for its highly productive, nutritious storage roots. This promising candidate space life-support crop has a sprawling habit and aggressive growth rate in favorable environments that demands substantial growing area. Shoot pruning is not a viable option for vine control because removal of the main shoot apex drastically inhibits storage-root initiation and development, and chemical growth retardants typically are not cleared for use with food crops. As part of a large effort by the NASA Specialized Center of Research and Training in Advanced Life Support to reduce equivalent system mass (ESM) for food production in space, the dilemma of vine management for sweetpotato was addressed in effort to conserve growth area without compromising root yield. Root yields from unbranched vines trained spirally around wire frames configured either in the shapes of cones or cylinders were similar to those from vines trained horizontally along the bench, but occupying only a small fraction of the bench area. This finding indicates that sweetpotato is highly adaptable to a variety of vine-training architectures. Planting a second plant in the growth container and training the two vines in opposite directions around frames enhanced root yield and number, but had little effect on average length of each vine or bench area occupied. Once again, root yields were similar for both configurations of wire support frames. The 3-4-month crop-production cycles for sweetpotato in the greenhouse spanned all seasons of multiple years during the course of the study, and although electric lighting was used for photoperiod control and to supplement photosynthetic light during low-light seasons, there still were differences in total light available across seasons. Light variations and other environmental differences among experiments in the greenhouse had more effects on vine

  15. INSTALLATION OF A POST-ACCIDENT CONFINEMENT HIGH-LEVEL RADIATION MONITORING SYSTEM IN THE KOLA NUCLEAR POWER STATION (UNIT 2) IN RUSSIA

    SciTech Connect

    GREENE,G.A.; GUPPY,J.G.

    1998-09-01

    This is the final report on the INSP project entitled, ``Post-Accident Confinement High-Level Radiation Monitoring System'' conducted by BNL under the authorization of Project Work Plan WBS 1.2.2.6 (Attachment 1). This project was initiated in February 1993 to assist the Russians in reducing risks associated with the continued operation of older Soviet-designed nuclear power plants, specifically the Kola VVER-440/230 Unit 2, through improved accident detection capability, specifically by the installation of a dual train high-level radiation detection system in the confinement of Unit 2 of the Kola NPP. The major technical objective of this project was to provide, install and make operational the necessary hardware inside the confinement of the Kola NPP Unit 2 to provide early and reliable warning of the release of radionuclides from the reactor into the confinement air space as an indication of the occurrence of a severe accident at the plant. In addition, it was intended to provide hands-on experience and training to the Russian plant workers in the installation, operation, calibration and maintenance of the equipment in order that they may use the equipment without continued US assistance as an effective measure to improve reactor safety at the plant.

  16. Effects of strength training, using a gravity-independent exercise system, performed during 110 days of simulated space station confinement.

    PubMed

    Alkner, Björn A; Berg, Hans E; Kozlovskaya, Inessa; Sayenko, Dimitri; Tesch, Per A

    2003-09-01

    The efficacy of a resistance exercise paradigm, using a gravity-independent flywheel principle, was examined in four men subjected to 110 days of confinement (simulation of flight of international crew on space station; SFINCSS-99). Subjects performed six upper- and lower-body exercises (calf raise, squat, back extension, seated row, lateral shoulder raise, biceps curl) 2-3 times weekly during the confinement. The exercise regimen consisted of four sets of ten repetitions of each exercise at estimated 80-100% of maximal effort. Work was measured and recorded in each exercise session. Maximal voluntary isometric force in the calf press, squat and back extension, was assessed at three different joint angles before and after confinement. Overall, the training load (work) increased in all subjects (range 16-108%) over the course of the intervention. Maximal voluntary isometric force was unchanged following confinement. Although the perceived level of strain and comfort varied between exercises and among individuals, the results of the present study suggest this resistance exercise regimen is effective in maintaining or even increasing performance and maximal force output during long-term confinement. These findings should be considered in the design of resistance exercise hardware and prescriptions to be employed on the International Space Station. PMID:12783231

  17. Active Response Gravity Offload System

    NASA Technical Reports Server (NTRS)

    Valle, Paul; Dungan, Larry; Cunningham, Thomas; Lieberman, Asher; Poncia, Dina

    2011-01-01

    The Active Response Gravity Offload System (ARGOS) provides the ability to simulate with one system the gravity effect of planets, moons, comets, asteroids, and microgravity, where the gravity is less than Earth fs gravity. The system works by providing a constant force offload through an overhead hoist system and horizontal motion through a rail and trolley system. The facility covers a 20 by 40-ft (approximately equals 6.1 by 12.2m) horizontal area with 15 ft (approximately equals4.6 m) of lifting vertical range.

  18. The JET Neutron Activation System

    NASA Astrophysics Data System (ADS)

    Roquemore, A. L.; Bertalot, L.; Esposito, B.; Jarvis, O. N.; Loughlin, M. J.; Sadler, G.; van Belle, P.

    1997-11-01

    The JET activation system provides the absolute value of the neutron yields as well as a check on the linearity of other neutron detector systems. The total neutron yield is standardized to one irradiation end reentrant in the top of the vessel, while the results from the other seven irradiation ends are normalized to this standard end and provide redundancy as well as information on the plasma position. A pneumatic transfer system is used to transfer up to five capsules containing elemental foils for a single discharge on JET. Eleven different elemental foils have been utilized to determine the yields from both DD and DT plasmas. By placing several different foils with different activation energy thresholds in a single capsule for one DT discharge, neutron spectral information has been obtained by use of the SAND-II unfolding code. A description of the activation system hardware and calibration of the activation detector system will be presented along with the results from the DT neutron calibration campaign.

  19. Modeling approaches for active systems

    NASA Astrophysics Data System (ADS)

    Herold, Sven; Atzrodt, Heiko; Mayer, Dirk; Thomaier, Martin

    2006-03-01

    To solve a wide range of vibration problems with the active structures technology, different simulation approaches for several models are needed. The selection of an appropriate modeling strategy is depending, amongst others, on the frequency range, the modal density and the control target. An active system consists of several components: the mechanical structure, at least one sensor and actuator, signal conditioning electronics and the controller. For each individual part of the active system the simulation approaches can be different. To integrate the several modeling approaches into an active system simulation and to ensure a highly efficient and accurate calculation, all sub models must harmonize. For this purpose, structural models considered in this article are modal state-space formulations for the lower frequency range and transfer function based models for the higher frequency range. The modal state-space formulations are derived from finite element models and/or experimental modal analyses. Consequently, the structure models which are based on transfer functions are directly derived from measurements. The transfer functions are identified with the Steiglitz-McBride iteration method. To convert them from the z-domain to the s-domain a least squares solution is implemented. An analytical approach is used to derive models of active interfaces. These models are transferred into impedance formulations. To couple mechanical and electrical sub-systems with the active materials, the concept of impedance modeling was successfully tested. The impedance models are enhanced by adapting them to adequate measurements. The controller design strongly depends on the frequency range and the number of modes to be controlled. To control systems with a small number of modes, techniques such as active damping or independent modal space control may be used, whereas in the case of systems with a large number of modes or with modes that are not well separated, other control

  20. CCSD(T) calculations of confined systems: In-crystal polarizabilities of F-, Cl-, O2 -, and S2 -

    NASA Astrophysics Data System (ADS)

    Holka, F.; Urban, M.; Neogrády, P.; Paldus, J.

    2014-12-01

    We explore dipole polarizabilities of the singly and doubly charged anions F-, Cl-, O2 -, and S2 - in an external, harmonic oscillator (HO) confining potential sum _i 1/2 ω 2ri2. We find that in contrast to F- and Cl- those for O2 - and S2 - are unrealistically high due to the instability of the corresponding restricted Hartree-Fock (RHF) solutions. Yet, already a relatively weak HO confining potential stabilizes their RHF solutions and eliminates any possible broken-symmetry solutions. The coupled-cluster theory with single, double and noniterative triple excitations (CCSD(T)) then yields considerably reduced polarizabilities for O2 - and S2 - relative to their unconfined values. We showed that polarizabilities of O2 - and S2 - are more sensitive to the strength of a confinement potential than are those for F- and Cl-. This enables us to relate the confining parameter ω with the known experimental polarizabilities for selected crystals (our "training set") and to find a specific confining parameter ω for which the CCSD(T) polarizability equals the experimental in-crystal polarizability of an anion in the training set. The latter may then be used as an alternative approach for determining the in-crystal polarizabilities of anions by exploiting the fact that the characteristic ω values depend linearly on the ionic radius of a cation participating in specific crystals containing these anions. Using this method we then calculate the isotropic dipole polarizabilities for F-, Cl-, O2 -, and S2 - embedded in the LiF, LiCl, NaF, NaCl, KF, KCl, ZnO, ZnS, MgO, MgS, CaO, CaS, SrO, SrS, BaO, BaS, and other crystals containing halogen, oxygen, or sulphur anions. We compare our results with those obtained via alternative models of the in-crystal anionic polarizabilities.

  1. Effect of confinement during cookoff of TATB

    NASA Astrophysics Data System (ADS)

    Hobbs, M. L.; Kaneshige, M. J.

    2014-05-01

    In practical scenarios, cookoff of explosives is a three-dimensional transient phenomenon where the rate limiting reactions may occur either in the condensed or gas phase. The effects of confinement are more dramatic when the rate-limiting reactions occur in the gas phase. Explosives can be self-confined, where the decomposing gases are contained within non-permeable regions of the explosive, or confined by a metal or composite container. In triaminotrinitrobenzene (TATB) based explosives, self-confinement is prevalent in plastic bonded explosives at full density. The time-to-ignition can be delayed by orders of magnitude if the reactive gases leave the confining apparatus. Delays in ignition can also occur when the confining apparatus has excess gas volume or ullage. Understanding the effects of confinement is required to accurately model explosive cookoff at various scales ranging from small laboratory experiments to large real systems.

  2. Behavior of magnetic field fluctuations during dynamo activity and its effect on energy confinement in a reversed-field pinch

    SciTech Connect

    Hattori, K.; Hirano, Y.; Shimada, T.; Yagi, Y.; Maejima, Y.; Hirota, I.; Ogawa, K. )

    1991-11-01

    Fluctuations of magnetic fields and related magnetohydrodynamic (MHD) phenomena are investigated in the TPE-1RM15 reversed-field pinch experiment ({ital Plasma} {ital Physics} {ital and} {ital Controlled} {ital Fusion} {ital Research}, 1986 (IAEA, Vienna, 1987), Vol. 2, p. 453). Mode analysis of fluctuations measured by multichannel coils reveals that nonlinear interactions between {ital m}=1 and {ital m}=0 modes, such as nonlinear coupling and phase locking, play significant roles during a dynamo event (i.e., the flux genertion process in the sustainment phase), resulting in transition from an unstable state to a stable state. Behaviors of these fluctuations are found to be toroidally asymmetrical due to strong nonlinearity. Study of the current ramping experiment shows that the inverse of global energy confinement time depends on the squared fluctuation level offset linearly, which is consistent with the prediction of the transport model based on the diffusion of stochastic field lines. By examining the dependence of the resistive part of the loop voltage on the fluctuation level, the input power to the electrons and ions are estimated to be about 70% and 30% of the total input power, respectively.

  3. Behavior of magnetic field fluctuations during dynamo activity and its effect on energy confinement in a reversed-field pinch

    NASA Astrophysics Data System (ADS)

    Hattori, K.; Hirano, Y.; Shimada, T.; Yagi, Y.; Maejima, Y.; Hirota, I.; Ogawa, K.

    1991-11-01

    Fluctuations of magnetic fields and related magnetohydrodynamic (MHD) phenomena are investigated in the TPE-1RM15 reversed-field pinch experiment [Plasma Physics and Controlled Fusion Research, 1986 (IAEA, Vienna, 1987), Vol. 2, p. 453]. Mode analysis of fluctuations measured by multichannel coils reveals that nonlinear interactions between m=1 and m=0 modes, such as nonlinear coupling and phase locking, play significant roles during a dynamo event (i.e., the flux genertion process in the sustainment phase), resulting in transition from an unstable state to a stable state. Behaviors of these fluctuations are found to be toroidally asymmetrical due to strong nonlinearity. Study of the current ramping experiment shows that the inverse of global energy confinement time depends on the squared fluctuation level offset linearly, which is consistent with the prediction of the transport model based on the diffusion of stochastic field lines. By examining the dependence of the resistive part of the loop voltage on the fluctuation level, the input power to the electrons and ions are estimated to be about 70% and 30% of the total input power, respectively.

  4. The activation system EASY-2007

    NASA Astrophysics Data System (ADS)

    Forrest, R. A.; Kopecky, J.

    2009-04-01

    Safety and waste management of materials for ITER, IFMIF and future power plants require knowledge of the activation caused by irradiation with neutrons, or in the case of IFMIF, deuterons. The European Activation System has been developed for such calculations and a new version was released earlier this year. This contains a large amount of nuclear data in the European Activation File covering neutron-, deuteron- and proton-induced cross sections. These data are input to the FISPACT code for activation calculations. EASY-2007 is being validated using integral and differential measurements. However, only a minority of reactions have experimental support and a statistical method is described that can test the complete library. Importance diagrams are useful in finding the dominant nuclides formed following irradiation and the reactions responsible for their production. These diagrams now cover energies above 20 MeV and examples of new dominant nuclides and reactions relevant to IFMIF are given.

  5. Solvent cavitation under solvophobic confinement.

    PubMed

    Ashbaugh, Henry S

    2013-08-14

    The stability of liquids under solvophobic confinement can tip in favor of the vapor phase, nucleating a liquid-to-vapor phase transition that induces attractive forces between confining surfaces. In the case of water adjacent to hydrophobic surfaces, experimental and theoretical evidence support confinement-mediated evaporation stabilization of biomolecular and colloidal assemblies. The macroscopic thermodynamic theory of cavitation under confinement establishes the connection between the size of the confining surfaces, interfacial free energies, and bulk solvent pressure with the critical evaporation separation and interfacial forces. While molecular simulations have confirmed the broad theoretical trends, a quantitative comparison based on independent measurements of the interfacial free energies and liquid-vapor coexistence properties has, to the best of our knowledge, not yet been performed. To overcome the challenges of simulating a large number of systems to validate scaling predictions for a three-dimensional fluid, we simulate both the forces and liquid-vapor coexistence properties of a two-dimensional Lennard-Jones fluid confined between solvophobic plates over a range of plate sizes and reservoir pressures. Our simulations quantitatively agree with theoretical predictions for solvent-mediated forces and critical evaporation separations once the length dependence of the solvation free energy of an individual confining plate is taken into account. The effective solid-liquid line tension length dependence results from molecular scale correlations for solvating microscopic plates and asymptotically decays to the macroscopic value for plates longer than 150 solvent diameters. The success of the macroscopic thermodynamic theory at describing two-dimensional liquids suggests application to surfactant monolayers to experimentally confirm confinement-mediated cavitation. PMID:23947875

  6. Impact of artificial lateral quantum confinement on exciton-spin relaxation in a two-dimensional GaAs electronic system

    SciTech Connect

    Kiba, Takayuki Murayama, Akihiro; Tanaka, Toru; Tamura, Yosuke; Higo, Akio; Thomas, Cedric; Samukawa, Seiji

    2014-10-15

    We demonstrate the effect of artificial lateral quantum confinement on exciton-spin relaxation in a GaAs electronic system. GaAs nanodisks (NDs) were fabricated from a quantum well (QW) by top-down nanotechnology using neutral-beam etching aided by protein-engineered bio-nano-templates. The exciton-spin relaxation time was 1.4 ns due to ND formation, significantly extended compared to 0.44 ns for the original QW, which is attributed to weakening of the hole-state mixing in addition to freezing of the carrier momentum. The temperature dependence of the spin-relaxation time depends on the ND thickness, reflecting the degree of quantum confinement.

  7. EDITORIAL: Special issue containing papers presented at the 11th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems Special issue containing papers presented at the 11th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems

    NASA Astrophysics Data System (ADS)

    Kolesnichenko, Ya.

    2010-08-01

    subsequent meetings (Aspenäs (1991), Trieste (1993), Princeton (1995), and JET/Abingdon (1997)) were entitled `Alpha Particles in Fusion Research'. During the JET/Abingdon meeting in 1997 it was decided to extend the topic by including other suprathermal particles, in particular accelerated electrons, and rename the meetings accordingly. The subsequent meetings with the current name `Energetic Particles in Magnetic Confinement Systems' were held in Naka (1999), Gothenburg (2001), San Diego (2003), Takayama (2005) and Kloster Seeon (2007). The most recent meeting in this series was held in Kyiv, Ukraine, in September 2009. This was an anniversary meeting, 20 years after the first meeting. Like the first meeting, it was hosted by the Institute for Nuclear Research, National Academy of Sciences of Ukraine. It was attended by about 80 researchers from 18 countries, ITER, and EC. The program of the meeting consisted of 78 presentations, including 12 invited talks, 16 oral contributed talks, and 50 posters, which were selected by the International Advisory Committee (IAC). The IAC consisted of 11 people representing EC (L.-G. Eriksson), Germany (S. Günter), Italy (F. Zonca), Japan (K. Shinohara and K. Toi), Switzerland (A. Fasoli), UK (S. Sharapov), Ukraine (Ya. Kolesnichenko—IAC Chair), USA (H. Berk, W. Heidbrink, and R. Nazikian). The meeting program covered a wide range of physics issues concerning energetic ions in toroidal fusion facilities—tokamaks, stellarators, and spherical tori. Many new interesting and practically important results of both experimental and theoretical studies were reported. The research presented covered topics such as instabilities driven by energetic ions, transport of energetic ions caused by plasma microturbulence and destabilized eigenmodes, non-linear phenomena induced by the instabilities, classical transport processes, effects of runaway electrons, diagnostics of energetic ions and plasmas, and aspects of ITER physics. In addition to these

  8. A Review of Quantum Confinement

    SciTech Connect

    Connerade, Jean-Patrick

    2009-12-03

    A succinct history of the Confined Atom problem is presented. The hydrogen atom confined to the centre of an impenetrable sphere counts amongst the exactly soluble problems of physics, alongside much more noted exact solutions such as Black Body Radiation and the free Hydrogen atom in absence of any radiation field. It shares with them the disadvantage of being an idealisation, while at the same time encapsulating in a simple way particular aspects of physical reality. The problem was first formulated by Sommerfeld and Welker - henceforth cited as SW - in connection with the behaviour of atoms at very high pressures, and the solution was published on the occasion of Pauli's 60th birthday celebration. At the time, it seemed that there was not much other connection with physical reality beyond a few simple aspects connected to the properties of atoms in solids, for which more appropriate models were soon developed. Thus, confined atoms attracted little attention until the advent of the metallofullerene, which provided the first example of a confined atom with properties quite closely related to those originally considered by SW. Since then, the problem has received much more attention, and many more new features of quantum confinement, quantum compression, the quantum Faraday cage, electronic reorganisation, cavity resonances, etc have been described, which are relevant to real systems. Also, a number of other situations have been uncovered experimentally to which quantum confinement is relevant. Thus, studies of the confined atom are now more numerous, and have been extended both in terms of the models used and the systems to which they can be applied. Connections to thermodynamics are explored through the properties of a confined two-level atom adapted from Einstein's celebrated model, and issues of dynamical screening of electromagnetic radiation by the confining shell are discussed in connection with the Faraday cage produced by a confining conducting shell. The

  9. Velocity shear stabilization of centrifugally confined plasma.

    PubMed

    Huang, Y M; Hassam, A B

    2001-12-01

    A magnetized, centrifugally confined plasma is subjected to a 3D MHD stability test. Ordinarily, the system is expected to be grossly unstable to "flute" interchanges of field lines. Numerical simulation shows though that the system is stable on account of velocity shear. This allows consideration of a magnetically confined plasma for thermonuclear fusion that has a particularly simple coil configuration. PMID:11736455

  10. Quark confinement in a constituent quark model

    SciTech Connect

    Langfeld, K.; Rho, M.

    1995-07-01

    On the level of an effective quark theory, we define confinement by the absence of quark anti-quark thresholds in correlation function. We then propose a confining Nambu-Jona-Lasinio-type model. The confinement is implemented in analogy to Anderson localization in condensed matter systems. We study the model`s phase structure as well as its behavior under extreme conditions, i.e. high temperature and/or high density.

  11. Demonstration of a time-integrated short line of sight neutron imaging system for inertial confinement fusion

    SciTech Connect

    Simpson, R. Danly, C.; Fatherley, V. E.; Merrill, F. E.; Volegov, P.; Wilde, C.; Christensen, K.; Fittinghoff, D.; Grim, G. P.; Izumi, N.; Jedlovec, D.; Skulina, K.

    2015-12-15

    The Neutron Imaging System (NIS) is an important diagnostic for understanding implosions of deuterium-tritium capsules at the National Ignition Facility. While the detectors for the existing system must be positioned 28 m from the source to produce sufficient imaging magnification and resolution, recent testing of a new short line of sight neutron imaging system has shown sufficient resolution to allow reconstruction of the source image with quality similar to that of the existing NIS on a 11.6 m line of sight. The new system used the existing pinhole aperture array and a stack of detectors composed of 2 mm thick high-density polyethylene converter material followed by an image plate. In these detectors, neutrons enter the converter material and interact with protons, which recoil and deposit energy within the thin active layer of the image plate through ionization losses. The described system produces time-integrated images for all neutron energies passing through the pinhole. We present details of the measurement scheme for this novel technique to produce energy-integrated neutron images as well as source reconstruction results from recent experiments at NIF.

  12. Demonstration of a time-integrated short line of sight neutron imaging system for inertial confinement fusion

    NASA Astrophysics Data System (ADS)

    Simpson, R.; Christensen, K.; Danly, C.; Fatherley, V. E.; Fittinghoff, D.; Grim, G. P.; Izumi, N.; Jedlovec, D.; Merrill, F. E.; Skulina, K.; Volegov, P.; Wilde, C.

    2015-12-01

    The Neutron Imaging System (NIS) is an important diagnostic for understanding implosions of deuterium-tritium capsules at the National Ignition Facility. While the detectors for the existing system must be positioned 28 m from the source to produce sufficient imaging magnification and resolution, recent testing of a new short line of sight neutron imaging system has shown sufficient resolution to allow reconstruction of the source image with quality similar to that of the existing NIS on a 11.6 m line of sight. The new system used the existing pinhole aperture array and a stack of detectors composed of 2 mm thick high-density polyethylene converter material followed by an image plate. In these detectors, neutrons enter the converter material and interact with protons, which recoil and deposit energy within the thin active layer of the image plate through ionization losses. The described system produces time-integrated images for all neutron energies passing through the pinhole. We present details of the measurement scheme for this novel technique to produce energy-integrated neutron images as well as source reconstruction results from recent experiments at NIF.

  13. Demonstration of a time-integrated short line of sight neutron imaging system for inertial confinement fusion.

    PubMed

    Simpson, R; Christensen, K; Danly, C; Fatherley, V E; Fittinghoff, D; Grim, G P; Izumi, N; Jedlovec, D; Merrill, F E; Skulina, K; Volegov, P; Wilde, C

    2015-12-01

    The Neutron Imaging System (NIS) is an important diagnostic for understanding implosions of deuterium-tritium capsules at the National Ignition Facility. While the detectors for the existing system must be positioned 28 m from the source to produce sufficient imaging magnification and resolution, recent testing of a new short line of sight neutron imaging system has shown sufficient resolution to allow reconstruction of the source image with quality similar to that of the existing NIS on a 11.6 m line of sight. The new system used the existing pinhole aperture array and a stack of detectors composed of 2 mm thick high-density polyethylene converter material followed by an image plate. In these detectors, neutrons enter the converter material and interact with protons, which recoil and deposit energy within the thin active layer of the image plate through ionization losses. The described system produces time-integrated images for all neutron energies passing through the pinhole. We present details of the measurement scheme for this novel technique to produce energy-integrated neutron images as well as source reconstruction results from recent experiments at NIF. PMID:26724078

  14. A 1.5-4 K detachable cold-sample transfer system: Application to inertially confined fusion with spin-polarized hydrogen fuels

    NASA Astrophysics Data System (ADS)

    Alexander, N.; Barden, J.; Fan, Q.; Honig, A.

    1991-11-01

    A compact cold-transfer apparatus for engaging and retrieving samples at liquid-helium temperatures (1.5-4 K), maintaining the samples at such temperatures for periods of hours, and subsequently inserting them in diverse apparatuses followed by disengagement, is described. The properties of several thermal radiation-insulating shrouds, necessary for very low sample temperatures, are presented. The immediate intended application is transportable target shells containing highly spin-polarized deuterons in solid HD or D2 for inertially confined fusion experiments. The system is also valuable for unpolarized high-density fusion fuels, as well as for other applications which are discussed.

  15. A 1. 5--4 Kelvin detachable cold-sample transfer system: Application to inertially confined fusion with spin-polarized hydrogens fuels

    SciTech Connect

    Alexander, N.; Barden, J.; Fan, Q.; Honig, A.

    1990-01-01

    A compact cold-transfer apparatus for engaging and retrieving samples at liquid helium temperatures (1.5--4K), maintaining the samples at such temperatures for periods of hours, and subsequently inserting them in diverse apparatuses followed by disengagement, is described. The properties of several thermal radiation-insulating shrouds, necessary for very low sample temperatures, are presented. The immediate intended application is transportable target-shells containing highly spin-polarized deuterons in solid HD or D{sub 2} for inertially confined fusion (ICF) experiments. The system is also valuable for unpolarized high-density fusion fuels, as well as for other applications which are discussed. 9 refs., 6 figs.

  16. A 1.5 to 4 kelvin detachable cold-sample transfer system: Application to inertially confined fusion with spin-polarized hydrogens fuels

    NASA Astrophysics Data System (ADS)

    Alexander, N.; Barden, J.; Fan, Q.; Honig, A.

    A compact cold-transfer apparatus for engaging and retrieving samples at liquid helium temperatures (1.5 to 4 K), maintaining the samples at such temperatures for periods of hours, and subsequently inserting them in diverse apparatuses followed by disengagement, is described. The properties of several thermal radiation-insulating shrouds, necessary for very low sample temperatures, are presented. The immediate intended application is transportable target-shells containing highly spin-polarized deuterons in solid HD or D(2) for inertially confined fusion (ICF) experiments. The system is also valuable for unpolarized high-density fusion fuels, as well as for other applications which are discussed.

  17. A 1. 5--4 K detachable cold-sample transfer system: Application to inertially confined fusion with spin-polarized hydrogen fuels

    SciTech Connect

    Alexander, N.; Barden, J.; Fan, Q.; Honig, A. )

    1991-11-01

    A compact cold-transfer apparatus for engaging and retrieving samples at liquid-helium temperatures (1.5--4 K), maintaining the samples at such temperatures for periods of hours, and subsequently inserting them in diverse apparatuses followed by disengagement, is described. The properties of several thermal radiation-insulating shrouds, necessary for very low sample temperatures, are presented. The immediate intended application is transportable target shells containing highly spin-polarized deuterons in solid HD or D{sub 2} for inertially confined fusion experiments. The system is also valuable for unpolarized high-density fusion fuels, as well as for other applications which are discussed.

  18. Epithelial junction formation requires confinement of Cdc42 activity by a novel SH3BP1 complex

    PubMed Central

    Elbediwy, Ahmed; Zihni, Ceniz; Terry, Stephen J.; Clark, Peter

    2012-01-01

    Epithelial cell–cell adhesion and morphogenesis require dynamic control of actin-driven membrane remodeling. The Rho guanosine triphosphatase (GTPase) Cdc42 regulates sequential molecular processes during cell–cell junction formation; hence, mechanisms must exist that inactivate Cdc42 in a temporally and spatially controlled manner. In this paper, we identify SH3BP1, a GTPase-activating protein for Cdc42 and Rac, as a regulator of junction assembly and epithelial morphogenesis using a functional small interfering ribonucleic acid screen. Depletion of SH3BP1 resulted in loss of spatial control of Cdc42 activity, stalled membrane remodeling, and enhanced growth of filopodia. SH3BP1 formed a complex with JACOP/paracingulin, a junctional adaptor, and CD2AP, a scaffolding protein; both were required for normal Cdc42 signaling and junction formation. The filamentous actin–capping protein CapZ also associated with the SH3BP1 complex and was required for control of actin remodeling. Epithelial junction formation and morphogenesis thus require a dual activity complex, containing SH3BP1 and CapZ, that is recruited to sites of active membrane remodeling to guide Cdc42 signaling and cytoskeletal dynamics. PMID:22891260

  19. Dislocation dynamics in confined geometry

    NASA Astrophysics Data System (ADS)

    Gómez-García, D.; Devincre, B.; Kubin, L.

    1999-05-01

    A simulation of dislocation dynamics has been used to calculate the critical stress for a threading dislocation moving in a confined geometry. The optimum conditions for conducting simulations in systems of various sizes, down to the nanometer range, are defined. The results are critically compared with the available theoretical and numerical estimates for the problem of dislocation motion in capped layers.

  20. Hydrogeologic characteristics and water quality of a confined sand unit in the surficial aquifer system, Hunter Army Airfield, Chatham County, Georgia

    USGS Publications Warehouse

    Gonthier, Gerard J.

    2012-01-01

    An 80-foot-deep well (36Q397, U.S. Geological Survey site identification 320146081073701) was constructed at Hunter Army Airfield to assess the potential of using the surficial aquifer system as a water source to irrigate a ballfield complex. A 300-foot-deep test hole was drilled beneath the ballfield complex to characterize the lithology and water-bearing characteristics of sediments above the Upper Floridan aquifer. The test hole was then completed as well 36Q397 open to a 19-foot-thick shallow, confined sand unit contained within the surficial aquifer system. A single-well, 24-hour aquifer test was performed by pumping well 36Q397 at a rate of 50 gallons per minute during July 13-14, 2011, to characterize the hydrologic properties of the shallow, confined sand unit. Two pumping events prior to the aquifer test affected water levels. Drawdown during all three pumping events and residual drawdown during recovery periods were simulated using the Theis formula on multiple changes in discharge rate. Simulated drawdown and residual drawdown match well with measured drawdown and residual drawdown using values of horizontal hydraulic conductivity and specific storage, which are typical for a confined sand aquifer. Based on the hydrologic parameters used to match simulated drawdown and residual drawdown to measured drawdown and residual drawdown, the transmissivity of the sand was determined to be about 400 feet squared per day. The horizontal hydraulic conductivity of the sand was determined to be about 20 feet per day. Analysis of a water-quality sample indicated that the water is suitable for irrigation. Sample analysis indicated a calcium-carbonate type water having a total dissolved solids concentration of 39 milligrams per liter. Specific conductance and concentrations of all analyzed constituents were below those that would be a concern for irrigation, and were below primary and secondary water-quality criteria levels.

  1. Elastic Properties of Lysozyme Confined in Nanoporous Polymer Films

    NASA Astrophysics Data System (ADS)

    Wang, Haoyu; Akcora, Pinar

    Retaining the conformational structure and bioactivity of immobilized proteins is important for biosensor designs and drug delivery systems. It is known that confined media provide a protective environment to the encapsulated proteins and prevent diffusion of the denaturant. In this study, different types of proteins (streptavidin, lysozyme and fibrinogen) were chemically attached into the nanopores of poly(methyl methacrylate) thin films. Heterogeneous flat surfaces with varying cylinder pore sizes (10-50 nm) were used to confine proteins of different sizes and shapes. Stiffness of protein functionalized nanopores was measured in nanoindentation experiments. Our results showed that streptavidin behaved more stiffly when pore dimension changed from micron to nanosize. Further, it was found that lysozyme confined within nanopores showed higher specific bioactivity than proteins on flat surfaces. These results on surface elasticity and protein activity may help in understanding protein interactions with surfaces of different topologies and chemistry.

  2. Active thermal control system evolution

    NASA Technical Reports Server (NTRS)

    Petete, Patricia A.; Ames, Brian E.

    1991-01-01

    The 'restructured' baseline of the Space Station Freedom (SSF) has eliminated many of the growth options for the Active Thermal Control System (ATCS). Modular addition of baseline technology to increase heat rejection will be extremely difficult. The system design and the available real estate no longer accommodate this type of growth. As the station matures during its thirty years of operation, a demand of up to 165 kW of heat rejection can be expected. The baseline configuration will be able to provide 82.5 kW at Eight Manned Crew Capability (EMCC). The growth paths necessary to reach 165 kW have been identified. Doubling the heat rejection capability of SSF will require either the modification of existing radiator wings or the attachment of growth structure to the baseline truss for growth radiator wing placement. Radiator performance can be improved by enlarging the surface area or by boosting the operating temperature with a heat pump. The optimal solution will require both modifications. The addition of growth structure would permit the addition of a parallel ATCS using baseline technology. This growth system would simplify integration. The feasibility of incorporating these growth options to improve the heat rejection capacity of SSF is under evaluation.

  3. Boundaries Matter for Confined Colloidal Glasses

    NASA Astrophysics Data System (ADS)

    Hunter, Gary L.; Edmond, Kazem V.; Weeks, Eric R.

    2012-02-01

    We confine dense colloidal suspensions within emulsion droplets to examine how confinement and properties of the confining medium affect the colloidal glass transition. Samples are imaged via fast confocal microscopy. By observing a wide range of droplet sizes and varying the viscosity of the external continuous phase, we separate finite size and boundary effects on particle motions within the droplet. Suspensions are composed of binary PMMA spheres in organic solvents while the external phases are simple mixtures of water and glycerol. In analogy with molecular super-cooled liquids and thin-film polymers, we find that confinement effects in colloidal systems are not merely functions of the finite size of the system, but are strongly dependent on the viscosity of the confining medium and interactions between particles and the interface of the two phases.

  4. Confinement of block copolymers

    SciTech Connect

    1995-12-31

    The following were studied: confinement of block copolymers, free surface confinement, effects of substrate interactions, random copolymers at homopolymer interfaces, phase separation in thin film polymer mixtures, buffing of polymer surfaces, and near edge x-ray absorption fine structure spectroscopy.

  5. Confinement Aquaculture. Final Report.

    ERIC Educational Resources Information Center

    Delaplaine School District, AR.

    The Delaplaine Agriculture Department Confinement Project, begun in June 1988, conducted a confinement aquaculture program by comparing the growth of channel catfish raised in cages in a pond to channel catfish raised in cages in the Black River, Arkansas. The study developed technology that would decrease costs in the domestication of fish, using…

  6. Indoor Confined Feedlots.

    PubMed

    Grooms, Daniel L; Kroll, Lee Anne K

    2015-07-01

    Indoor confined feedlots offer advantages that make them desirable in northern climates where high rainfall and snowfall occur. These facilities increase the risk of certain health risks, including lameness and tail injuries. Closed confinement can also facilitate the rapid spread of infectious disease. Veterinarians can help to manage these health risks by implementing management practices to reduce their occurrence. PMID:26139194

  7. Elastic membranes in confinement.

    PubMed

    Bostwick, J B; Miksis, M J; Davis, S H

    2016-07-01

    An elastic membrane stretched between two walls takes a shape defined by its length and the volume of fluid it encloses. Many biological structures, such as cells, mitochondria and coiled DNA, have fine internal structure in which a membrane (or elastic member) is geometrically 'confined' by another object. Here, the two-dimensional shape of an elastic membrane in a 'confining' box is studied by introducing a repulsive confinement pressure that prevents the membrane from intersecting the wall. The stage is set by contrasting confined and unconfined solutions. Continuation methods are then used to compute response diagrams, from which we identify the particular membrane mechanics that generate mitochondria-like shapes. Large confinement pressures yield complex response diagrams with secondary bifurcations and multiple turning points where modal identities may change. Regions in parameter space where such behaviour occurs are then mapped. PMID:27440257

  8. Thermostating highly confined fluids.

    PubMed

    Bernardi, Stefano; Todd, B D; Searles, Debra J

    2010-06-28

    In this work we show how different use of thermostating devices and modeling of walls influence the mechanical and dynamical properties of confined nanofluids. We consider a two dimensional fluid undergoing Couette flow using nonequilibrium molecular dynamics simulations. Because the system is highly inhomogeneous, the density shows strong fluctuations across the channel. We compare the dynamics produced by applying a thermostating device directly to the fluid with that obtained when the wall is thermostated, considering also the effects of using rigid walls. This comparison involves an analysis of the chaoticity of the fluid and evaluation of mechanical properties across the channel. We look at two thermostating devices with either rigid or vibrating atomic walls and compare them with a system only thermostated by conduction through vibrating atomic walls. Sensitive changes are observed in the xy component of the pressure tensor, streaming velocity, and density across the pore and the Lyapunov localization of the fluid. We also find that the fluid slip can be significantly reduced by rigid walls. Our results suggest caution in interpreting the results of systems in which fluid atoms are thermostated and/or wall atoms are constrained to be rigid, such as, for example, water inside carbon nanotubes. PMID:20590213

  9. Manually controlled neutron-activation system

    NASA Astrophysics Data System (ADS)

    Johns, R. A.; Carothers, G. A.

    1982-01-01

    A manually controlled neutron activation system, the Manual Reactor Activation System, was designed and built and has been operating at one of the Savannah River Plant's production reactors. With this system, samples can be irradiated for up to 24 hours and pneumatically transferred to a shielded repository for decay until their activity is low enough for them to be handled at a radiobench. The Manual Reactor Activation System was built to provide neutron activation of solid waste forms for the Alternative Waste Forms Leach Testing Program. Neutron activation of the bulk sample prior to leaching permits sensitive multielement radiometric analyses of the leachates.

  10. Wave activated power generation system

    SciTech Connect

    Ono, Y.

    1983-08-09

    A wave activated power generation system of the float type is disclosed, comprising at least one piston-cylinder device having an anchored cylinder and a piston slidable in the cylinder and cooperating with the cylinder to form a pumping chamber above the piston and a low pressure chamber below the piston. The cylinder has an intake port and an exhaust port both formed at an upper port thereof to communicate with the pumping chamber and each provided with a check valve. A float is connected through a cable to the piston of the piston- cylinder device. A pair of fluid storages are connected to the intake port and the exhaust port of the pumping chamber, respectively. A waterwheel generator is driven by the fluid flowing from one of the fluid storages to another. A pressure regulating device is connected to the low pressure chamber so as to maintain the low pressure chamber at a pressure lower than the pressure in the pumping chamber, the difference in pressure ceaselessly applying a downward force on the piston to keep the cable in a tensed condition.

  11. Propagating confined states in phase dynamics

    NASA Technical Reports Server (NTRS)

    Brand, Helmut R.; Deissler, Robert J.

    1992-01-01

    Theoretical treatment is given to the possibility of the existence of propagating confined states in the nonlinear phase equation by generalizing stationary confined states. The nonlinear phase equation is set forth for the case of propagating patterns with long wavelengths and low-frequency modulation. A large range of parameter values is shown to exist for propagating confined states which have spatially localized regions which travel on a background with unique wavelengths. The theoretical phenomena are shown to correspond to such physical systems as spirals in Taylor instabilities, traveling waves in convective systems, and slot-convection phenomena for binary fluid mixtures.

  12. Confinement of Coulomb balls

    SciTech Connect

    Arp, O.; Block, D.; Klindworth, M.; Piel, A.

    2005-12-15

    A model for the confinement of the recently discovered Coulomb balls is proposed. These spherical three-dimensional plasma crystals are trapped inside a rf discharge under gravity conditions and show an unusual structural order in complex plasmas. Measurements of the thermophoretic force acting on the trapped dust particles and simulations of the plasma properties of the discharge are presented. The proposed model of confinement considers thermophoretic, ion-drag, and electric field forces, and shows excellent agreement with the observations. The findings suggest that self-confinement does not significantly contribute to the structural properties of Coulomb balls.

  13. Enzymatic reactions in confined environments

    NASA Astrophysics Data System (ADS)

    Küchler, Andreas; Yoshimoto, Makoto; Luginbühl, Sandra; Mavelli, Fabio; Walde, Peter

    2016-05-01

    Within each biological cell, surface- and volume-confined enzymes control a highly complex network of chemical reactions. These reactions are efficient, timely, and spatially defined. Efforts to transfer such appealing features to in vitro systems have led to several successful examples of chemical reactions catalysed by isolated and immobilized enzymes. In most cases, these enzymes are either bound or adsorbed to an insoluble support, physically trapped in a macromolecular network, or encapsulated within compartments. Advanced applications of enzymatic cascade reactions with immobilized enzymes include enzymatic fuel cells and enzymatic nanoreactors, both for in vitro and possible in vivo applications. In this Review, we discuss some of the general principles of enzymatic reactions confined on surfaces, at interfaces, and inside small volumes. We also highlight the similarities and differences between the in vivo and in vitro cases and attempt to critically evaluate some of the necessary future steps to improve our fundamental understanding of these systems.

  14. Enzymatic reactions in confined environments.

    PubMed

    Küchler, Andreas; Yoshimoto, Makoto; Luginbühl, Sandra; Mavelli, Fabio; Walde, Peter

    2016-05-01

    Within each biological cell, surface- and volume-confined enzymes control a highly complex network of chemical reactions. These reactions are efficient, timely, and spatially defined. Efforts to transfer such appealing features to in vitro systems have led to several successful examples of chemical reactions catalysed by isolated and immobilized enzymes. In most cases, these enzymes are either bound or adsorbed to an insoluble support, physically trapped in a macromolecular network, or encapsulated within compartments. Advanced applications of enzymatic cascade reactions with immobilized enzymes include enzymatic fuel cells and enzymatic nanoreactors, both for in vitro and possible in vivo applications. In this Review, we discuss some of the general principles of enzymatic reactions confined on surfaces, at interfaces, and inside small volumes. We also highlight the similarities and differences between the in vivo and in vitro cases and attempt to critically evaluate some of the necessary future steps to improve our fundamental understanding of these systems. PMID:27146955

  15. A New Approach for the Statistical Thermodynamic Theory of the Nonextensive Systems Confined in Different Finite Traps

    NASA Astrophysics Data System (ADS)

    Tang, Hui-Yi; Wang, Jian-Hui; Ma, Yong-Li

    2014-06-01

    For a small system at a low temperature, thermal fluctuation and quantum effect play important roles in quantum thermodynamics. Starting from micro-canonical ensemble, we generalize the Boltzmann-Gibbs statistical factor from infinite to finite systems, no matter the interactions between particles are considered or not. This generalized factor, similar to Tsallis's q-form as a power-law distribution, has the restriction of finite energy spectrum and includes the nonextensivities of the small systems. We derive the exact expression for distribution of average particle numbers in the interacting classical and quantum nonextensive systems within a generalized canonical ensemble. This expression in the almost independent or elementary excitation quantum finite systems is similar to the corresponding ones obtained from the conventional grand-canonical ensemble. In the reconstruction for the statistical theory of the small systems, we present the entropy of the equilibrium systems and equation of total thermal energy. When we investigate the thermodynamics for the interacting nonextensive systems, we obtain the system-bath heat exchange and "uncompensated heat" which are in the thermodynamical level and independent on the detail of the system-bath coupling. For ideal finite systems, with different traps and boundary conditions, we calculate some thermodynamic quantities, such as the specific heat, entropy, and equation of state, etc. Particularly at low temperatures for the small systems, we predict some novel behaviors in the quantum thermodynamics, including internal entropy production, heat exchanges between the system and its surroundings and finite-size effects on the free energy.

  16. What Is an Activity? Appropriating an Activity-Centric System

    NASA Astrophysics Data System (ADS)

    Yarosh, Svetlana; Matthews, Tara; Moran, Thomas P.; Smith, Barton

    Activity-Centric Computing (ACC) systems seek to address the fragmentation of office work across tools and documents by allowing users to organize work around the computational construct of an Activity. Defining and structuring appropriate Activities within a system poses a challenge for users that must be overcome in order to benefit from ACC support. We know little about how knowledge workers appropriate the Activity construct. To address this, we studied users’ appropriation of a production-quality ACC system, Lotus Activities, for everyday work by employees in a large corporation. We contribute to a better understanding of how users articulate their individual and collaborative work in the system by providing empirical evidence of their patterns of appropriation. We conclude by discussing how our findings can inform the design of other ACC systems for the workplace.

  17. Polymer Crystallization under Confinement

    NASA Astrophysics Data System (ADS)

    Floudas, George

    Recent efforts indicated that polymer crystallization under confinement can be substantially different from the bulk. This can have important technological applications for the design of polymeric nanofibers with tunable mechanical strength, processability and optical clarity. However, the question of how, why and when polymers crystallize under confinement is not fully answered. Important studies of polymer crystallization confined to droplets and within the spherical nanodomains of block copolymers emphasized the interplay between heterogeneous and homogeneous nucleation. Herein we report on recent studies1-5 of polymer crystallization under hard confinement provided by model self-ordered AAO nanopores. Important open questions here are on the type of nucleation (homogeneous vs. heterogeneous), the size of critical nucleus, the crystal orientation and the possibility to control the overall crystallinity. Providing answers to these questions is of technological relevance for the understanding of nanocomposites containing semicrystalline polymers. In collaboration with Y. Suzuki, H. Duran, M. Steinhart, H.-J. Butt.

  18. Bacteria in Confined Spaces

    NASA Astrophysics Data System (ADS)

    Wilking, Connie; Weitz, David

    2010-03-01

    Bacterial cells can display differentiation between several developmental pathways, from planktonic to matrix-producing, depending upon the colony conditions. We study the confinement of bacteria in hydrogels as well as in liquid-liquid double emulsion droplets and observe the growth and morphology of these colonies as a function of time and environment. Our results can give insight into the behavior of bacterial colonies in confined spaces that can have applications in the areas of food science, cosmetics, and medicine.

  19. Study of the 3D Coronal Magnetic Field of Active Region 11117 Around the Time of a Confined Flare Using a Data-Driven CESE-MHD Model

    NASA Astrophysics Data System (ADS)

    Jiang, C.; Feng, X.; Wu, S.; Hu, Q.

    2012-12-01

    Non-potentiality of the solar coronal magnetic field accounts for the solar explosion like flares and CMEs. We apply a data-driven CESE-MHD model to investigate the three-dimensional (3D) coronal magnetic field of NOAA active region (AR) 11117 around the time of a C-class confined flare occurred on 2010 October 25. The CESE-MHD model, based on the spacetime conservation-element and solution-element scheme, is designed to focus on the magnetic-field evolution and to consider a simplified solar atomsphere with finite plasma β. Magnetic vector-field data derived from the observations at the photoshpere is inputted directly to constrain the model. Assuming that the dynamic evolution of the coronal magnetic field can be approximated by successive equilibria, we solve a time sequence of MHD equilibria basing on a set of vector magnetograms for AR 11117 taken by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO) around the time of flare. The model qualitatively reproduces the basic structures of the 3D magnetic field, as supported by the visual similarity between the field lines and the coronal loops observed by the Atmospheric Imaging Assembly (AIA), which shows that the coronal field can indeed be well characterized by the MHD equilibrium in most time. The magnetic configuration changes very limited during the studied time interval of two hours. A topological analysis reveals that the small flare is correlated with a bald patch (BP, where the magnetic field is tangent to the photoshpere), suggesting that the energy release of the flare can be understood by magnetic reconnection associated with the BP separatrices. The total magnetic flux and energy keep increasing slightly in spite of the flare, while the magnetic free energy drops during the flare with an amount of 1.7 × 1030 erg, which can be interpreted as the energy budget released by the minor C-class flare.

  20. Data base management systems activities

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The Data Management System-1100 is designed to operate in conjunction with the UNIVAC 1100 Series Operating System on any 1100 Series computer. DMS-1100 is divided into the following four major software components: (1) Data Definition Languages (DDL); (2) Data Management Routine (DMR); (3) Data Manipulation Languages (DML); and (4) Data Base Utilities (DBU). These software components are described in detail.

  1. Orbiter active thermal control system description

    NASA Technical Reports Server (NTRS)

    Laubach, G. E.

    1975-01-01

    A brief description of the Orbiter Active Thermal Control System (ATCS) including (1) major functional requirements of heat load, temperature control and heat sink utilization, (2) the overall system arrangement, and (3) detailed description of the elements of the ATCS.

  2. Stiffness and Confinement Ratios of SMA Wire Jackets for Confining Concrete

    NASA Astrophysics Data System (ADS)

    Choi, Eunsoo; Kim, Dong Joo; Youn, Heejung

    2014-07-01

    This article discusses the effects of the stiffness and confinement ratios of shape memory alloy (SMA) wire jackets on the behavior of confined concrete. SMA wire jackets are an effective confining material to improve concrete behavior; for example, by increasing peak strength and failure strain. The stiffness and confinement ratios of fiber-reinforced polymer jackets have been extensively discussed and their effects are well known. However, assessment of the stiffness and confinement ratios of SMA wire jackets has not previously been conducted. In this study, we investigate the effects of the stiffness and confinement ratios of steel jackets, and then compare the results with those of SMA wire jackets. In general, the stiffness ratios of SMA wire jackets are relatively smaller than those of steel jackets, and most of them have lower stiffness ratios because the Young's moduli of the SMAs are relatively small. The active confining pressure of the SMA wires does not improve the lower stiffness-ratio effect since the amount of active confining pressure is not sufficiently large.

  3. Finite particle size drives defect-mediated domain structures in strongly confined colloidal liquid crystals

    NASA Astrophysics Data System (ADS)

    Gârlea, Ioana C.; Mulder, Pieter; Alvarado, José; Dammone, Oliver; Aarts, Dirk G. A. L.; Lettinga, M. Pavlik; Koenderink, Gijsje H.; Mulder, Bela M.

    2016-06-01

    When liquid crystals are confined to finite volumes, the competition between the surface anchoring imposed by the boundaries and the intrinsic orientational symmetry-breaking of these materials gives rise to a host of intriguing phenomena involving topological defect structures. For synthetic molecular mesogens, like the ones used in liquid-crystal displays, these defect structures are independent of the size of the molecules and well described by continuum theories. In contrast, colloidal systems such as carbon nanotubes and biopolymers have micron-sized lengths, so continuum descriptions are expected to break down under strong confinement conditions. Here, we show, by a combination of computer simulations and experiments with virus particles in tailor-made disk- and annulus-shaped microchambers, that strong confinement of colloidal liquid crystals leads to novel defect-stabilized symmetrical domain structures. These finite-size effects point to a potential for designing optically active microstructures, exploiting the as yet unexplored regime of highly confined liquid crystals.

  4. A single-shot, multiwavelength electro-optic data-acquisition system for inertial confinement fusion applications (invited).

    PubMed

    Donaldson, W R; Zhao, C; Ji, L; Roides, R G; Miller, K; Beeman, B

    2012-10-01

    Electro-optic data-acquisition systems encode the output from voltage-history diagnostics onto optical signals. The optical signals can propagate long distances over fiber-optic links without degrading the bandwidth of the encoded signal while protecting the recording electronics from overvoltage damage. The sinusoidal response and tolerance to high-input voltages of the Mach-Zehnder modulator used for the encoding leads to the additional advantage of a high dynamic range and a reduced need for manually swapping attenuators. We have demonstrated a single-shot, electro-optic data-acquisition system with a 600:1 dynamic range. This system provides optical isolation and a bandwidth of 6 GHz. The prototype system uses multiple optical wavelengths to allow for the multiplexing of up to eight signals onto one photodetector. PMID:23126900

  5. A single-shot, multiwavelength electro-optic data-acquisition system for inertial confinement fusion applications (invited)

    SciTech Connect

    Donaldson, W. R.; Zhao, C.; Ji, L.; Roides, R. G.; Miller, K.; Beeman, B.

    2012-10-15

    Electro-optic data-acquisition systems encode the output from voltage-history diagnostics onto optical signals. The optical signals can propagate long distances over fiber-optic links without degrading the bandwidth of the encoded signal while protecting the recording electronics from overvoltage damage. The sinusoidal response and tolerance to high-input voltages of the Mach-Zehnder modulator used for the encoding leads to the additional advantage of a high dynamic range and a reduced need for manually swapping attenuators. We have demonstrated a single-shot, electro-optic data-acquisition system with a 600:1 dynamic range. This system provides optical isolation and a bandwidth of 6 GHz. The prototype system uses multiple optical wavelengths to allow for the multiplexing of up to eight signals onto one photodetector.

  6. Dielectric elastomer vibrissal system for active tactile sensing

    NASA Astrophysics Data System (ADS)

    Conn, Andrew T.; Pearson, Martin J.; Pipe, Anthony G.; Welsby, Jason; Rossiter, Jonathan

    2012-04-01

    Rodents are able to dexterously navigate confined and unlit environments by extracting spatial and textural information with their whiskers (or vibrissae). Vibrissal-based active touch is suited to a variety of applications where vision is occluded, such as search-and-rescue operations in collapsed buildings. In this paper, a compact dielectric elastomer vibrissal system (DEVS) is described that mimics the vibrissal follicle-sinus complex (FSC) found in rodents. Like the vibrissal FSC, the DEVS encapsulates all sensitive mechanoreceptors at the root of a passive whisker within an antagonistic muscular system. Typically, rats actively whisk arrays of macro-vibrissae with amplitudes of up to +/-25°. It is demonstrated that these properties can be replicated by exploiting the characteristic large actuation strains and passive compliance of dielectric elastomers. A prototype DEVS is developed using VHB 4905 and embedded strain gauges bonded to the root of a tapered whisker. The DEVS is demonstrated to produce a maximum rotational output of +/-22.8°. An electro-mechanical model of the DEVS is derived, which incorporates a hyperelastic material model and Euler- Bernoulli beam equations. The model is shown to predict experimental measurements of whisking stroke amplitude and whisker deflection.

  7. Experiment system of LAMOST active optics

    NASA Astrophysics Data System (ADS)

    Cui, Xiangqun; Su, Ding; Li, Guoping; Yao, Zhengqiu; Zhang, Zhengcao; Li, Yeping; Zhang, Yong; Wang, You; Xu, Xinqi; Wang, Hai

    2004-10-01

    Active optics is the most difficult part in LAMOST project. Especially for the segmented reflecting Schmidt plate Ma, in which both segmented mirror active optics and thin mirror (or deformable mirror) active optics are applied. To test and optimize the thin mirror active optics of Ma, and to approach the reality of operating environment of the telescope, an outdoor experiment system has been established. This experiment system is also a `small LAMOST" with one sub-mirror of the primary mirror Mb and one sub-mirror of the Schmidt plate Ma, and with full scale in spacing (40 meters) between Ma and Mb. many parts of LAMOST were tested in the experiment system except segmented mirror active optics. Especially for force actuators, thin mirror support system, friction driving of the alt-azimuth mounting and its control system, wave front test along such a long optical path. This paper presents the experiment system, research and developments, and some experiment results.

  8. Modeling Cytoskeletal Active Matter Systems

    NASA Astrophysics Data System (ADS)

    Blackwell, Robert

    Active networks of filamentous proteins and crosslinking motor proteins play a critical role in many important cellular processes. One of the most important microtubule-motor protein assemblies is the mitotic spindle, a self-organized active liquid-crystalline structure that forms during cell division and that ultimately separates chromosomes into two daughter cells. Although the spindle has been intensively studied for decades, the physical principles that govern its self-organization and function remain mysterious. To evolve a better understanding of spindle formation, structure, and dynamics, I investigate course-grained models of active liquid-crystalline networks composed of microtubules, modeled as hard spherocylinders, in diffusive equilibrium with a reservoir of active crosslinks, modeled as hookean springs that can adsorb to microtubules and and translocate at finite velocity along the microtubule axis. This model is investigated using a combination of brownian dynamics and kinetic monte carlo simulation. I have further refined this model to simulate spindle formation and kinetochore capture in the fission yeast S. pombe. I then make predictions for experimentally realizable perturbations in motor protein presence and function in S. pombe.

  9. High speed hybrid active system

    NASA Astrophysics Data System (ADS)

    Gonzalez, Ignacio F.; Chang, Fu-Kuo; Qing, Peter X.; Kumar, Amrita; Zhang, David

    2005-05-01

    A novel piezoelectric/fiber-optic system is developed for long-term health monitoring of aerospace vehicles and structures. The hybrid diagnostic system uses the piezoelectric actuators to input a controlled excitation to the structure and the fiber optic sensors to capture the corresponding structural response. The aim of the system is to detect changes in structures such as those found in aerospace applications (damage, cracks, aging, etc.). This system involves the use of fiber Bragg gratings, which may be either bonded to the surface of the material or embedded within it in order to detect the linear strain component produced by the excitation waves generate by an arbitrary waveform generator. Interrogation of the Bragg gratings is carried out using a high speed fiber grating demodulation unit and a high speed data acquisition card to provide actuation input. With data collection and information processing; is able to determine the condition of the structure. The demands on a system suitable for detecting ultrasonic acoustic waves are different than for the more common strain and temperature systems. On the one hand, the frequency is much higher, with typical values for ultrasonic frequencies used in non-destructive testing ranging from 100 kHz up to several MHz. On the other hand, the related strain levels are much lower, normally in the μstrain range. Fiber-optic solutions for this problem do exist and are particularly attractive for ultrasonic sensing as the sensors offer broadband detection capability.

  10. The Us3 Protein of Herpes Simplex Virus 1 Inhibits T Cell Signaling by Confining Linker for Activation of T Cells (LAT) Activation via TRAF6 Protein*

    PubMed Central

    Yang, Yin; Wu, Songfang; Wang, Yu; Pan, Shuang; Lan, Bei; Liu, Yaohui; Zhang, Liming; Leng, Qianli; Chen, Da; Zhang, Cuizhu; He, Bin; Cao, Youjia

    2015-01-01

    Herpes simplex virus 1 (HSV-1) is the most prevalent human virus and causes global morbidity because the virus is able to infect multiple cell types. Remarkably, HSV infection switches between lytic and latent cycles, where T cells play a critical role. However, the precise way of virus-host interactions is incompletely understood. Here we report that HSV-1 productively infected Jurkat T-cells and inhibited antigen-induced T cell receptor activation. We discovered that HSV-1-encoded Us3 protein interrupted TCR signaling and interleukin-2 production by inactivation of the linker for activation of T cells. This study unveils a mechanism by which HSV-1 intrudes into early events of TCR-mediated cell signaling and may provide novel insights into HSV infection, during which the virus escapes from host immune surveillance. PMID:25907557

  11. Youth pathways to placement: the influence of gender, mental health need and trauma on confinement in the juvenile justice system.

    PubMed

    Espinosa, Erin M; Sorensen, Jon R; Lopez, Molly A

    2013-12-01

    Although the juvenile crime rate has generally declined, the involvement of girls in the juvenile justice system has been increasing. Possible explanations for this gender difference include the impact of exposure to trauma and mental health needs on developmental pathways and the resulting influence of youth's involvement in the justice system. This study examined the influence of gender, mental health needs and trauma on the risk of out-of-home placement for juvenile offenders. The sample included youth referred to three urban juvenile probation departments in Texas between January 1, 2007 and December 31, 2008 and who received state-mandated mental health screening (N = 34,222; 30.1 % female). The analysis revealed that, for both genders, elevated scores on the seven factor-analytically derived subscales of a mental health screening instrument (Alcohol and Drug Use, Depressed-Anxious, Somatic Complaints, Suicidal Ideation, Thought Disturbance, and Traumatic Experiences), especially related to past traumatic experiences, influenced how deeply juveniles penetrated the system. The findings suggest that additional research is needed to determine the effectiveness of trauma interventions and the implementation of trauma informed systems for youth involved with the juvenile justice system. PMID:23824982

  12. Special section containing papers presented at the 13th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (Beijing, China, 17-20 September 2013) Special section containing papers presented at the 13th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (Beijing, China, 17-20 September 2013)

    NASA Astrophysics Data System (ADS)

    Lin, Z.

    2014-10-01

    In magnetic fusion plasmas, a significant fraction of the kinetic pressure is contributed by superthermal charged particles produced by auxiliary heating (fast ions and electrons) and fusion reactions (a-particles). Since these energetic particles are often far away from thermal equilibrium due to their non-Maxwellian distribution and steep pressure gradients, the free energy can excite electromagnetic instabilities to intensity levels well above the thermal fluctuations. The resultant electromagnetic turbulence could induce large transport of energetic particles, which could reduce heating efficiency, degrade overall plasma confinement, and damage fusion devices. Therefore, understanding and predicting energetic particle confinement properties are critical to the success of burning plasma experiments such as ITER since the ignition relies on plasma self-heating by a-particles. To promote international exchanges and collaborations on energetic particle physics, the biannual conference series under the auspices of the International Atomic Energy Agency (IAEA) were help in Kyiv (1989), Aspenas (1991), Trieste (1993), Princeton (1995), JET/Abingdon (1997), Naka (1999), Gothenburg (2001), San Diego (2003), Takayama (2005), Kloster Seeon (2007), Kyiv (2009), and Austin (2011). The papers in this special section were presented at the most recent meeting, the 13th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems, which was hosted by the Fusion Simulation Center, Peking University, Beijing, China (17-20 September 2013). The program of the meeting consisted of 71 presentations, including 13 invited talks, 26 oral contributed talks, 30 posters, and 2 summary talks, which were selected by the International Advisory Committee (IAC). The IAC members include H. Berk, L.G. Eriksson, A. Fasoli, W. Heidbrink, Ya. Kolesnichenko, Ph. Lauber, Z. Lin, R. Nazikian, S. Pinches, S. Sharapov, K. Shinohara, K. Toi, G. Vlad, and X.T. Ding. The conference program

  13. Influence of the confining pressure on precursory and rupture processes of Westerly granite.

    NASA Astrophysics Data System (ADS)

    Passelegue, Francois; Nicolas, Aurelien; Madonna, Claudio; Schubnel, Alexandre

    2016-04-01

    In the shallow crust, brittle deformation mechanisms lead to damage and rupture of rocks. These mechanisms are generally described by non-linear stress relations and decrease of the elastic moduli due to microcrak opening and sliding. However, failure mode depends on confining pressure and ranges from axial splitting to shear localization. Here we report experiments on Westerly granite samples deformed under controlled upper crustal stress conditions in the laboratory. Experiments were conducted under triaxial loading (σ1>σ2=σ3) at confining pressures (σ3) ranging from 2 to 50 MPa (similar to upper crustal stress conditions) and at constant axial strain rate 10-5/s. Usual a dual gain system, a high frequency acoustic monitoring array recorded particles acceleration during macroscopic rupture of the intact specimen and premonitory background microseismicity. Secondly, acoustic sensors were used in an active way to measure the evolution of elastic wave velocities. In addition, we used an amplified strain gage to record the dynamic stress change during the dynamic rupture. Our preliminary results show that increasing confining pressure leads to the transition between axial cracks opening to shear localization. This result is supported by the moment tensor solutions of acoustic emissions and CT scan imaging of the post mortem sample. In addition, we systematically observe an exponential increase of the premonitory activity up to the shear failure of the sample. While the intensity of this precursory activity increase with the confining pressure in term of energy, the crack density leading to the failure of the sample is independent of the confinement. We show that the dynamic rupture occurs in only few microseconds, suggesting a rupture speed close to the shear wave velocity. In addition, the ratio between the stress drop and the peak of stress increases with the confinement. This result suggest that the weakening of faulting increases with the confinement. Finally

  14. Emergent phenomena in manganites under spatial confinement

    NASA Astrophysics Data System (ADS)

    Shen, Jian; Z. Ward, T.; F. Yin, L.

    2013-01-01

    It is becoming increasingly clear that the exotic properties displayed by correlated electronic materials such as high-Tc superconductivity in cuprates, colossal magnetoresistance (CMR) in manganites, and heavy-fermion compounds are intimately related to the coexistence of competing nearly degenerate states which couple simultaneously active degrees of freedom—charge, lattice, orbital, and spin states. The striking phenomena associated with these materials are due in a large part to spatial electronic inhomogeneities, or electronic phase separation (EPS). In many of these hard materials, the functionality is a result of the soft electronic component that leads to self-organization. In this paper, we review our recent work on a novel spatial confinement technique that has led to some fascinating new discoveries about the role of EPS in manganites. Using lithographic techniques to confine manganite thin films to length scales of the EPS domains that reside within them, it is possible to simultaneously probe EPS domains with different electronic states. This method allows for a much more complete view of the phases residing in a material and gives vital information on phase formation, movement, and fluctuation. Pushing this trend to its limit, we propose to control the formation process of the EPS using external local fields, which include magnetic exchange field, strain field, and electric field. We term the ability to pattern EPS “electronic nanofabrication." This method allows us to control the global physical properties of the system at a very fundamental level, and greatly enhances the potential for realizing true oxide electronics.

  15. Confined Space Imager (CSI) Software

    SciTech Connect

    Karelilz, David

    2013-07-03

    The software provides real-time image capture, enhancement, and display, and sensor control for the Confined Space Imager (CSI) sensor system The software captures images over a Cameralink connection and provides the following image enhancements: camera pixel to pixel non-uniformity correction, optical distortion correction, image registration and averaging, and illumination non-uniformity correction. The software communicates with the custom CSI hardware over USB to control sensor parameters and is capable of saving enhanced sensor images to an external USB drive. The software provides sensor control, image capture, enhancement, and display for the CSI sensor system. It is designed to work with the custom hardware.

  16. Holographic confinement in inhomogeneous backgrounds

    NASA Astrophysics Data System (ADS)

    Marolf, Donald; Wien, Jason

    2016-08-01

    As noted by Witten, compactifying a d-dimensional holographic CFT on an S 1 gives a class of ( d - 1)-dimensional confining theories with gravity duals. The proto-typical bulk solution dual to the ground state is a double Wick rotation of the AdS d+1 Schwarzschild black hole known as the AdS soliton. We generalize such examples by allowing slow variations in the size of the S 1, and thus in the confinement scale. Coefficients governing the second order response of the system are computed for 3 ≤ d ≤ 8 using a derivative expansion closely related to the fluid-gravity correspondence. The primary physical results are that i) gauge-theory flux tubes tend to align orthogonal to gradients and along the eigenvector of the Hessian with the lowest eigenvalue, ii) flux tubes aligned orthogonal to gradients are attracted to gradients for d ≤ 6 but repelled by gradients for d ≥ 7, iii) flux tubes are repelled by regions where the second derivative along the tube is large and positive but are attracted to regions where the eigenvalues of the Hessian are large and positive in directions orthogonal to the tube, and iv) for d > 3, inhomogeneities act to raise the total energy of the confining vacuum above its zeroth order value.

  17. Order, Disorder and Confinement

    SciTech Connect

    D'Elia, M.; Di Giacomo, A.; Pica, C.

    2006-01-12

    Studying the order of the chiral transition for Nf = 2 is of fundamental importance to understand the mechanism of color confinement. We present results of a numerical investigation on the order of the transition by use of a novel strategy in finite size scaling analysis. The specific heat and a number of susceptibilities are compared with the possible critical behaviours. A second order transition in the O(4) and O(2) universality classes are excluded. Substantial evidence emerges for a first order transition. Results are in agreement with those found by studying the scaling properties of a disorder parameter related to the dual superconductivity mechanism of color confinement.

  18. Centrally activated pipe snubbing system

    DOEpatents

    Cawley, William E.

    1985-01-01

    An electromechanical pipe snubbing system and an electromechanical pipe snubber. In the system, each pipe snubber, in a set of pipe snubbers, has an electromechanical mechanism to lock and unlock the snubber. A sensor, such as a seismometer, measures a quantity related to making a snubber locking or unlocking decision. A control device makes an electrical connection between a power supply and each snubber's electromechanical mechanism to simultaneously lock each snubber when the sensor measurement indicates a snubber locking condition. The control device breaks the connection to simultaneously unlock each snubber when the sensor measurement indicates a snubber unlocking condition. In the snubber, one end of the shaft slides within a bore in one end of a housing. The other end of the shaft is rotatably attached to a pipe; the other end of the housing is rotatively attached to a wall. The snubber's electromechanical mechanism locks the slidable end of the shaft to the housing and unlocks that end from the housing. The electromechanical mechanism permits remote testing and lockup status indication for each snubber.

  19. Diblock Copolymers under Nano-Confinement

    NASA Astrophysics Data System (ADS)

    Meng, Dong; Yin, Yuhua; Wang, Qiang

    2009-03-01

    Nano-confinement strongly affects and can thus be used to control the self-assembled morphology of block copolymers. Understanding such effects is of both fundamental and practical interest. In this work, we use real-space self-consistent field calculations with high accuracy to study the self-assembled morphology of diblock copolymers (DBC) under nano-confinement for several systems, including 1D lamellae-forming DBC confined between two homogeneous and parallel surfaces, in nano-pores, and on topologically patterned substrates; 2D cylinder-forming DBC on chemically strip-patterned substrates; and 3D gyroid- forming DBC confined between two homogeneous and parallel surfaces. The stable phases are identified through free-energy comparison, and our SCF results are compared with available experiments and Monte Carlo simulations in each case.

  20. Exercise as Countermeasure for Decrements of Performance and Mood During Long-Term Confinement

    NASA Astrophysics Data System (ADS)

    Schneider, Stefan; Piacentini, Maria F.; Meeusen, Romain; Brummer, Vera; Struder, Heiko K.

    2008-06-01

    In order to prepare for crewed exploratory missions to Moon and Mars, currently ESA is participating in two isolation studies, MARS 500 and on the antarctis station CONCORDIA. The aim of the present study is to identify exercise as a countermeasure to confinement addicted changes in mood. It is planned (1) to look at influences of exercise on the serotonergic system, which is known to have mood regulating effects and (2) to record changes in brain cortical activity due to exercise. Mood and performance tests will be carried out several times during the confinement. We hypothesize that impairments in mood due to the isolated and confined environment together with a lack of physical exercise lead to decreases in mental and perceptual motor performance whereas physical exercise linked with an activation of the serotonergic system will improve mood and therefore performance irrespectively of the environmental restrictions.

  1. Triplet exciton confinement for enhanced fluorescent organic light-emitting diodes using a co-host system

    NASA Astrophysics Data System (ADS)

    Yoo, Han Kyu; Lee, Ho Won; Lee, Song Eun; Kim, Young Kwan; Kim, Se Hyun; Yoon, Seung Soo; Park, Jaehoon

    2016-05-01

    In this work, the co-host system within an emitting layer (EML) consists of the host and triplet managing (TM) host materials. A set of EML structures was fabricated with various concentrations of the TM host (0, 10, 30, 50, and 70%). The TM host triplet energy level is lower than the energy levels of the host and the guest, which leads to a reduction in the triplet exciton density and the singlet-triplet annihilation of the guest. Blue fluorescent organic light-emitting diodes exhibit a maximum luminous efficiency (LE) and an external quantum efficiency (EQE) of 9.74 cd/A and 4.92%, respectively. In addition, the efficiency roll-off ratios of the LE and the EQE are 14.25 and 13.16%, respectively.

  2. Development of diagnostic and manipulation systems for space-charge dominated electron beams and confined electron plasmas in ELTRAP

    SciTech Connect

    Rome, M.; Cavaliere, F.; Maero, G.; Paroli, B.; Pozzoli, R.; Cavenago, M.; Ikram, M.

    2013-03-19

    Modifications have been implemented in the Penning-Malmberg device ELTRAP aimed at performing studies on the dynamics of space-charge dominated nanosecond electron bunches traveling along the magnetic field. In particular, a Thomson backscattering apparatus has been developed where an infrared (IR) laser pulse collides with the bunched electron beam. The frequency-shifted backscattered radiation, acquired by means of a photomultiplier (PMT), can be exploited to evaluate information on energy, energy spread and density of the bunch. The achievable sensitivity of the diagnostics has been estimated, and valuable information on the main parameters affecting the signal-to-noise (S/N) ratio has been obtained [B. Paroli, F. Cavaliere, M. Cavenago, F. De Luca, M. Ikram, G. Maero, C. Marini, R. Pozzoli, and M. Rome, JINST 7, P01008 (2012)]. A series of upgrades are under way, aimed at increasing the S/N ratio through the use of a new laser for the electron source, the insertion of a stray light shield, and the optimization of the detection electronics. Moreover, electromagnetic simulations relevant to the design and implementation of a microwave heating system are presented. The generation of an electron plasma in ELTRAP by means of a low-power radio frequency (RF) drive in the MHz range applied on one of the trap electrodes and under ultra-high vacuum (UHV) conditions has previously been demonstrated [B. Paroli, F. De Luca, G. Maero, F. Pozzoli, and M. Rome, Plasma Sources Sci. Technol. 19, 045013 (2010)]. The new heating system will allow the extension of the RF studies to the GHz range and in particular the production of a more energetic electron plasma via cyclotron resonant excitation.

  3. Development of diagnostic and manipulation systems for space-charge dominated electron beams and confined electron plasmas in ELTRAP

    NASA Astrophysics Data System (ADS)

    Romé, M.; Cavaliere, F.; Cavenago, M.; Ikram, M.; Maero, G.; Paroli, B.; Pozzoli, R.

    2013-03-01

    Modifications have been implemented in the Penning-Malmberg device ELTRAP aimed at performing studies on the dynamics of space-charge dominated nanosecond electron bunches traveling along the magnetic field. In particular, a Thomson backscattering apparatus has been developed where an infrared (IR) laser pulse collides with the bunched electron beam. The frequency-shifted backscattered radiation, acquired by means of a photomultiplier (PMT), can be exploited to evaluate information on energy, energy spread and density of the bunch. The achievable sensitivity of the diagnostics has been estimated, and valuable information on the main parameters affecting the signal-to-noise (S/N) ratio has been obtained [B. Paroli, F. Cavaliere, M. Cavenago, F. De Luca, M. Ikram, G. Maero, C. Marini, R. Pozzoli, and M. Romé, JINST 7, P01008 (2012)]. A series of upgrades are under way, aimed at increasing the S/N ratio through the use of a new laser for the electron source, the insertion of a stray light shield, and the optimization of the detection electronics. Moreover, electromagnetic simulations relevant to the design and implementation of a microwave heating system are presented. The generation of an electron plasma in ELTRAP by means of a low-power radio frequency (RF) drive in the MHz range applied on one of the trap electrodes and under ultra-high vacuum (UHV) conditions has previously been demonstrated [B. Paroli, F. De Luca, G. Maero, F. Pozzoli, and M. Romé, Plasma Sources Sci. Technol. 19, 045013 (2010)]. The new heating system will allow the extension of the RF studies to the GHz range and in particular the production of a more energetic electron plasma via cyclotron resonant excitation.

  4. Identifying Host Sources of Fecal Pollution: Diversity of Escherichia coli in Confined Dairy and Swine Production Systems

    PubMed Central

    Lu, Zexun; Lapen, David; Scott, Andrew; Dang, Angela; Topp, Edward

    2005-01-01

    Repetitive extragenic palindromic PCR fingerprinting of Escherichia coli is one microbial source tracking approach for identifying the host source origin of fecal pollution in aquatic systems. The construction of robust known-source libraries is expensive and requires an informed sampling strategy. In many types of farming systems, waste is stored for several months before being released into the environment. In this study we analyzed, by means of repetitive extragenic palindromic PCR using the enterobacterial repetitive intergenic consensus primers and comparative analysis using the Bionumerics software, collections of E. coli obtained from a dairy farm and from a swine farm, both of which stored their waste as a slurry in holding tanks. In all fecal samples, obtained from either barns or holding tanks, the diversity of the E. coli populations was underrepresented by collections of 500 isolates. In both the dairy and the swine farms, the diversity of the E. coli community was greater in the manure holding tank than in the barn, when they were sampled on the same date. In both farms, a comparison of stored manure samples collected several months apart suggested that the community composition changed substantially in terms of the detected number, absolute identity, and relative abundance of genotypes. Comparison of E. coli populations obtained from 10 different locations in either holding tank suggested that spatial variability in the E. coli community should be accounted for when sampling. Overall, the diversity in E. coli populations in manure slurry storage facilities is significant and likely is problematic with respect to library construction for microbial source tracking applications. PMID:16204513

  5. Phase behavior, diffusion, structural characteristics, and pH of aqueous hydrophobic ionic liquid confined media: insights into microviscosity and microporsity in the [C4C4im][NTf2] + water system.

    PubMed

    Nanda, Raju; Kumar, Anil

    2015-01-29

    We present our studies on the physicochemical properties of water confined in Dibutylimidazolium bis(trifluoromethanesulfonylimide) ([C4C4im][NTf2]) reverse micelles through the NMR relaxation measurements that provide us an understanding of microviscosity and pH in the confined condition. We present experimental results on phase behavior, diffusion, structural characteristics and pH in aqueous ionic liquid-confined media. The ternary phase diagram was constructed by the cloud point measurements and the microheterogeneous regions were detected by the measurement of bulk viscosity and diffusion coefficients of K4[Fe(CN)6] inside the homogeneous microemulsion systems through the cyclic voltammetric (CV) measurements. The size of the microemulsion systems was characterized by the dynamic light scattering (DLS) method. The (1)H NMR spectra of homogeneous microemulsion systems were taken which indicates the presence of bound and free water molecules inside the microemulsion system. The NMR spin-lattice relaxation time (T1) of water molecules in its homogeneous microemulsion systems were measured and the reorientational correlation time (τc) of water molecules obtained from it indicates that the fluidity of homogeneous confined media decreases with the decrease in the composition of water. Microviscosity of the aqueous confined media was calculated from the measured T1 relaxation time values by applying the Debye-Stokes equation and correlated with the bulk viscosity of the samples. It was observed that both the microviscosity and bulk viscosity show inverse relationship. The fraction of bound and free water molecules were calculated from the measured T1 values. NMR spin-spin relaxation time (T2) of water molecules in its homogeneous microemulsion systems were measured with the varying pH of the aqueous core. A change in the T2 relaxation time of the water proton was observed proposing an exchange of proton between the H2O and -OH group of the TX-100 molecules. Finally

  6. Fractional statistics and confinement

    NASA Astrophysics Data System (ADS)

    Gaete, P.; Wotzasek, C.

    2005-02-01

    It is shown that a pointlike composite having charge and magnetic moment displays a confining potential for the static interaction while simultaneously obeying fractional statistics in a pure gauge theory in three dimensions, without a Chern-Simons term. This result is distinct from the Maxwell-Chern-Simons theory that shows a screening nature for the potential.

  7. Plasma confinement at JET

    NASA Astrophysics Data System (ADS)

    Nunes, I.; JET Contributors

    2016-01-01

    Operation with a Be/W wall at JET (JET-ILW) has an impact on scenario development and energy confinement with respect to the carbon wall (JET-C). The main differences observed were (1) strong accumulation of W in the plasma core and (2) the need to mitigate the divertor target temperature to avoid W sputtering by Be and other low Z impurities and (3) a decrease of plasma energy confinement. A major difference is observed on the pedestal pressure, namely a reduction of the pedestal temperature which, due to profile stiffness the plasma core temperature is also reduced leading to a degradation of the global confinement. This effect is more pronounced in low β N scenarios. At high β N, the impact of the wall on the plasma energy confinement is mitigated by the weaker plasma energy degradation with power relative to the IPB98(y, 2) scaling calculated empirically for a CFC first wall. The smaller tolerable impurity concentration for tungsten (<10-5) compared to that of carbon requires the use of electron heating methods to prevent W accumulation in the plasma core region as well as gas puffing to avoid W entering the plasma core by ELM flushing and reduction of the W source by decreasing the target temperature. W source and the target temperature can also be controlled by impurity seeding. Nitrogen and Neon have been used and with both gases the reduction of the W source and the target temperature is observed. Whilst more experiments with Neon are necessary to assess its impact on energy confinement, a partial increase of plasma energy confinement is observed with Nitrogen, through the increase of edge temperature. The challenge for scenario development at JET is to extend the pulse length curtailed by its transient behavior (W accumulation or MHD), but more importantly by the divertor target temperature limits. Re-optimisation of the scenarios to mitigate the effect of the change of wall materials maintaining high global energy confinement similar to JET-C is

  8. Confined deep water system development on the accretionary wedge (Miocene, Kahramanmaraş Foreland Basin, S turkey)

    NASA Astrophysics Data System (ADS)

    Gül, Murat; Cronin, Bryan T.; Gürbüz, Kemal

    2012-09-01

    According to theoretical studies, the foreland basin consists of: accretionary wedge (including wedge top or piggyback basin), foredeep, forebulge and backbulge depozones. All of them are parallel to the orogenic belts of the overlying and underlying plates. The closure of the southern branch of the Neotethys during the Late Cretaceous led to an oblique collision of the Arabian Plate and the Anatolide-Taurides Platform, leading to the development of the Miocene Kahramanmaraş Foreland Basin (KFB). Thus, the promontory shape of the Arabian Plate prevented the development of an accretionary wedge parallel to the orogenic belt. The accretionary wedge of the KFB includes blocks of various sizes and age (mainly Mesozoic limestone) scattered within an Early Tertiary matrix (mass wasting deposits and shallow to deep marine sediments). At the beginning of the Miocene, transtensional tectonism led to the development of half-graben basins on top of the accretionary wedge. These basins (namely; the Tekir and Çukurhisar) also cut the foredeep of the KFB obliquely (in contrast with the theoretical study). This paper focuses on the evolution and fillings of those basins. Initially, claystone and basin margin reef deposits filled the half-graben basins as a consequence of the Lower Miocene sea invasion. Then, long and narrow conglomeratic channels starting from the northern edge of the basins (fan-delta) progressed southwards, passing into sandy lobes, then into claystones. An activation of the boundary faults of the wedge top basin stopped the progression of the Lower-Middle Miocene sediments and led to their deformation. Then, the sedimentation of the KFB shifted towards the basin centre during the Middle Miocene.

  9. Confinement free energy of flexible polyelectrolytes in spherical cavities.

    PubMed

    Kumar, Rajeev; Muthukumar, M

    2008-05-14

    A weakly charged flexible polyelectrolyte chain in a neutral spherical cavity is analyzed by using self-consistent field theory within an explicit solvent model. Assuming the radial symmetry for the system, it is found that the confinement of the chain leads to creation of a charge density wave along with the development of a potential difference across the center of cavity and the surface. We show that the solvent entropy plays an important role in the free energy of the confined system. For a given radius of the spherical cavity and fixed charge density along the backbone of the chain, solvent and small ion entropies dominate over all other contributions when chain lengths are small. However, with the increase in chain length, chain conformational entropy and polymer-solvent interaction energy also become important. Our calculations reveal that energy due to electrostatic interactions plays a minor role in the free energy. Furthermore, we show that the total free energy under spherical confinement is not extensive in the number of monomers. Results for the osmotic pressure and mean activity coefficient for monovalent salt are presented. We demonstrate that fluctuations at one-loop level lower the free energy and corrections to the osmotic pressure and mean activity coefficient of the salt are discussed. Finite size corrections are shown to widen the range of validity of the fluctuation analysis. PMID:18532843

  10. Morphology of turbidite systems within an active continental margin (the Palomares Margin, western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Perez-Hernandez, S.; Comas, M. C.; Escutia, C.

    2014-08-01

    The Palomares Margin, an NNE-SSW segment of the South Iberian Margin located between the Alboran and the Algerian-Balearic basins, is dissected by two major submarine canyon systems: the Gata (in the South) and the Alías-Almanzora (in the North). New swath bathymetry, side-scan sonar images, accompanied by 5 kHz and TOPAS subbottom profiles, allow us to recognize these canyons as Mediterranean examples of medium-sized turbidite systems developed in a tectonically active margin. The Gata Turbidite System is confined between residual basement seamounts and exhibits incised braided channels that feed a discrete deep-sea fan, which points to a dominantly coarse-grained turbiditic system. The Alías-Almanzora Turbidite System, larger and less confined, is a good example of nested turbiditic system within the canyon. Concentric sediment waves characterize the Alías-Almanzora deep-sea fan, and the size and acoustic character of these bedforms suggest a fine-grained turbidite system. Both canyons are deeply entrenched on a narrow continental shelf and terminate at the base of the continental slope as channels that feed deep sea fans. While the Alías-Almanzora Turbidite System is the offshore continuation of seasonal rivers, the Gata Turbidite System is exclusively formed by headward erosion along the continental slope. In both cases, left-lateral transpressive deformation influences their location, longitudinal profiles, incision at the upper sections, and canyon bending associated with specific fault segments.

  11. Electrofreezing of confined water.

    PubMed

    Zangi, Ronen; Mark, Alan E

    2004-04-15

    We report results from molecular dynamics simulations of the freezing transition of TIP5P water molecules confined between two parallel plates under the influence of a homogeneous external electric field, with magnitude of 5 V/nm, along the lateral direction. For water confined to a thickness of a trilayer we find two different phases of ice at a temperature of T=280 K. The transformation between the two, proton-ordered, ice phases is found to be a strong first-order transition. The low-density ice phase is built from hexagonal rings parallel to the confining walls and corresponds to the structure of cubic ice. The high-density ice phase has an in-plane rhombic symmetry of the oxygen atoms and larger distortion of hydrogen bond angles. The short-range order of the two ice phases is the same as the local structure of the two bilayer phases of liquid water found recently in the absence of an electric field [J. Chem. Phys. 119, 1694 (2003)]. These high- and low-density phases of water differ in local ordering at the level of the second shell of nearest neighbors. The results reported in this paper, show a close similarity between the local structure of the liquid phase and the short-range order of the corresponding solid phase. This similarity might be enhanced in water due to the deep attractive well characterizing hydrogen bond interactions. We also investigate the low-density ice phase confined to a thickness of 4, 5, and 8 molecular layers under the influence of an electric field at T=300 K. In general, we find that the degree of ordering decreases as the distance between the two confining walls increases. PMID:15267616

  12. Data on geochemical and hydraulic properties of a characteristic confined/unconfined aquifer system of the younger Pleistocene in northeast Germany

    NASA Astrophysics Data System (ADS)

    Merz, C.; Steidl, J.

    2015-06-01

    The paper presents a database of hydrochemical and hydraulic groundwater measurements of a younger Pleistocene multilayered, unconfined/confined aquifer system in NE Germany. The Institute of Landscape Hydrology of the Leibniz Centre for Agricultural Landscape Research (ZALF) operates seven groundwater monitoring wells in the Quillow catchment located in the Uckermark region (federal state of Brandenburg, Germany). From July 2000 to March 2014, water samples were collected periodically on different days of the year and at depths between 3 and 5 m (shallow wells) and 16 and 24 m (deeper wells) below the surface. The parameters pH value, redox potential, electric conductivity, water temperature, oxygen content, spectral absorption coefficient and concentration of hydrogen carbonate, ammonium, phosphate, chloride, bromide, nitrite, sulfate, sodium, potassium, magnesium, calcite, dissolved organic carbon, iron(II) and manganese were determined for each sample (doi:10.4228/ZALF.2000.266). The measurements, taken over a period of 14 years, include a high variation of hydraulic situations represented by a corresponding database of 19 000 recorded groundwater heads. The hydraulic head was measured between 2000 and 2014 (doi:10.4228/ZALF.2000.272).

  13. Long-term geochemical and hydraulic measurements in a characteristic confined/unconfined aquifer system of the younger Pleistocene in northeast Germany

    NASA Astrophysics Data System (ADS)

    Merz, C.; Steidl, J.

    2015-01-01

    The paper presents a data base of hydrochemical and hydraulic groundwater measurements of a younger Pleistocene multilayered, unconfined/confined aquifer system in NE Germany. The Institute of Landscape Hydrology of the Leibniz Centre for Agricultural Landscape Research (ZALF) e. V. operates seven groundwater monitoring wells in the Quillow catchment located in the Uckermark region (Federal State of Brandenburg, Germany). From July 2000 to March 2014, water samples were collected periodically on different days of the year and at depths between 3 and 5 m (shallow wells) and 20 and 25 m (deeper wells) below the surface. The parameters pH value, redox potential, electric conductivity, water temperature, oxygen content, spectral absorption coefficient and concentration of hydrogen carbonate, ammonium, phosphate, chloride, bromite, nitrite, sulfate, sodium, potassium, magnesium, calcite, dissolved organic carbon, iron(II) and manganese were determined for each sample (doi:10.4228/ZALF.2000.266). The measurements, taken over a period of 14 years, include a high variation of hydraulic situations represented by a corresponding database of detected groundwater heads. The hydraulic head was measured between 2000 and 2014 (doi:10.4228/ZALF.2000.272).

  14. A phase-field approach to no-slip boundary conditions in dissipative particle dynamics and other particle models for fluid flow in geometrically complex confined systems.

    PubMed

    Xu, Zhijie; Meakin, Paul

    2009-06-21

    Dissipative particle dynamics (DPD) is an effective mesoscopic particle model with a lower computational cost than molecular dynamics because of the soft potentials that it employs. However, the soft potential is not strong enough to prevent the DPD particles that are used to represent the fluid from penetrating solid boundaries represented by stationary DPD particles. A phase-field variable, phi(x,t), is used to indicate the phase at point x and time t, with a smooth transition from -1 (phase 1) to +1 (phase 2) across the interface. We describe an efficient implementation of no-slip boundary conditions in DPD models that combines solid-liquid particle-particle interactions with reflection at a sharp boundary located with subgrid scale accuracy using the phase field. This approach can be used for arbitrarily complex flow geometries and other similar particle models (such as smoothed particle hydrodynamics), and the validity of the model is demonstrated by DPD simulations of flow in confined systems with various geometries. PMID:19548707

  15. Active microrheology in active matter systems: Mobility, intermittency, and avalanches.

    PubMed

    Reichhardt, C; Reichhardt, C J Olson

    2015-03-01

    We examine the mobility and velocity fluctuations of a driven particle moving through an active matter bath of self-mobile disks for varied density or area coverage and varied activity. We show that the driven particle mobility can exhibit nonmonotonic behavior that is correlated with distinct changes in the spatiotemporal structures that arise in the active media. We demonstrate that the probe particle velocity distributions exhibit specific features in the different dynamic regimes and identify an activity-induced uniform crystallization that occurs for moderate activity levels and is distinct from the previously observed higher activity cluster phase. The velocity distribution in the cluster phase has telegraph noise characteristics produced when the probe particle moves alternately through high-mobility areas that are in the gas state and low-mobility areas that are in the dense phase. For higher densities and large activities, the system enters what we characterize as an active jamming regime. Here the probe particle moves in intermittent jumps or avalanches that have power-law-distributed sizes that are similar to the avalanche distributions observed for nonactive disk systems near the jamming transition. PMID:25871116

  16. PASS: Creating Physically Active School Systems

    ERIC Educational Resources Information Center

    Ciotto, Carol M.; Fede, Marybeth H.

    2014-01-01

    PASS, a Physically Active School System, is a program by which school districts and schools utilize opportunities for school-based physical activity that enhance overall fitness and cognition, which can be broken down into four integral parts consisting of connecting, communicating, collaborating, and cooperating. There needs to be an…

  17. Active impedance matching of complex structural systems

    NASA Technical Reports Server (NTRS)

    Macmartin, Douglas G.; Miller, David W.; Hall, Steven R.

    1991-01-01

    Viewgraphs on active impedance matching of complex structural systems are presented. Topics covered include: traveling wave model; dereverberated mobility model; computation of dereverberated mobility; control problem: optimal impedance matching; H2 optimal solution; statistical energy analysis (SEA) solution; experimental transfer functions; interferometer actuator and sensor locations; active strut configurations; power dual variables; dereverberation of complex structure; dereverberated transfer function; compensators; and relative power flow.

  18. Bifurcated equilibria in centrifugally confined plasma

    SciTech Connect

    Shamim, I.; Teodorescu, C.; Guzdar, P. N.; Hassam, A. B.; Clary, R.; Ellis, R.; Lunsford, R.

    2008-12-15

    A bifurcation theory and associated computational model are developed to account for abrupt transitions observed recently on the Maryland Centrifugal eXperiment (MCX) [R. F. Ellis et al. Phys. Plasmas 8, 2057 (2001)], a supersonically rotating magnetized plasma that relies on centrifugal forces to prevent thermal expansion of plasma along the magnetic field. The observed transitions are from a well-confined, high-rotation state (HR-mode) to a lower-rotation, lesser-confined state (O-mode). A two-dimensional time-dependent magnetohydrodynamics code is used to simulate the dynamical equilibrium states of the MCX configuration. In addition to the expected viscous drag on the core plasma rotation, a momentum loss term is added that models the friction of plasma on the enhanced level of neutrals expected in the vicinity of the insulators at the throats of the magnetic mirror geometry. At small values of the external rotation drive, the plasma is not well-centrifugally confined and hence experiences the drag from near the insulators. Beyond a critical value of the external drive, the system makes an abrupt transition to a well-centrifugally confined state in which the plasma has pulled away from the end insulator plates; more effective centrifugal confinement lowers the plasma mass near the insulators allowing runaway increases in the rotation speed. The well-confined steady state is reached when the external drive is balanced by only the viscosity of the core plasma. A clear hysteresis phenomenon is shown.

  19. A GASFLOW analysis of a steam explosion accident in a typical light-water reactor confinement building

    SciTech Connect

    Travis, J.R.; Wilson, T.L.; Spore, J.W.; Lam, K.L.; Rao, D.V.

    1994-09-01

    Steam over-pressurization resulting from ex-vessel steam explosion (fuel-coolant interaction) may pose a serious challenge to the integrity of a typical light-water reactor confinement building. If the steam generation rate exceeds the removal capacity of the Airborne Activity Confinement System, confinement over pressurization occurs. Thus, there is a large potential for an uncontrolled and unfiltered release of fission products from the confinement atmosphere to the environment at the time of the steam explosion. The GASFLOW computer code was used to analyze the effects of a hypothetical steam explosion and the transport of steam and hydrogen throughout a typical light-water reactor confinement building. The effects of rapid pressurization and the resulting forces on the internal structures and the heat exchanger service bay hatch covers were calculated. Pressurization of the ventilation system and the potential damage to the ventilation fans and high-efficiency particulate air filters were assessed. Because of buoyancy forces and the calculated confinement velocity field, the hydrogen diffuses and mixes in the confinement atmosphere but tends to be transported to its upper region.

  20. Totally confined explosive welding

    NASA Technical Reports Server (NTRS)

    Bement, L. J. (Inventor)

    1978-01-01

    The undesirable by-products of explosive welding are confined and the association noise is reduced by the use of a simple enclosure into which the explosive is placed and in which the explosion occurs. An infrangible enclosure is removably attached to one of the members to be bonded at the point directly opposite the bond area. An explosive is completely confined within the enclosure at a point in close proximity to the member to be bonded and a detonating means is attached to the explosive. The balance of the enclosure, not occupied by explosive, is filled with a shaped material which directs the explosive pressure toward the bond area. A detonator adaptor controls the expansion of the enclosure by the explosive force so that the enclosure at no point experiences a discontinuity in expansion which causes rupture. The use of the technique is practical in the restricted area of a space station.

  1. Phase Transitions in Model Active Systems

    NASA Astrophysics Data System (ADS)

    Redner, Gabriel S.

    The amazing collective behaviors of active systems such as bird flocks, schools of fish, and colonies of microorganisms have long amazed scientists and laypeople alike. Understanding the physics of such systems is challenging due to their far-from-equilibrium dynamics, as well as the extreme diversity in their ingredients, relevant time- and length-scales, and emergent phenomenology. To make progress, one can categorize active systems by the symmetries of their constituent particles, as well as how activity is expressed. In this work, we examine two categories of active systems, and explore their phase behavior in detail. First, we study systems of self-propelled spherical particles moving in two dimensions. Despite the absence of an aligning interaction, this system displays complex emergent dynamics, including phase separation into a dense active solid and dilute gas. Using simulations and analytic modeling, we quantify the phase diagram and separation kinetics. We show that this nonequilibrium phase transition is analogous to an equilibrium vapor-liquid system, with binodal and spinodal curves and a critical point. We also characterize the dense active solid phase, a unique material which exhibits the structural signatures of a crystalline solid near the crystal-hexatic transition point, as well as anomalous dynamics including superdiffusive motion on intermediate timescales. We also explore the role of interparticle attraction in this system. We demonstrate that attraction drastically changes the phase diagram, which contains two distinct phase-separated regions and is reentrant as a function of propulsion speed. We interpret this complex situation with a simple kinetic model, which builds from the observed microdynamics of individual particles to a full description of the macroscopic phase behavior. We also study active nematics, liquid crystals driven out of equilibrium by energy-dissipating active stresses. The equilibrium nematic state is unstable in these

  2. Active imaging system with Faraday filter

    DOEpatents

    Snyder, J.J.

    1993-04-13

    An active imaging system has a low to medium powered laser transmitter and receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination while eliminating solar background.

  3. Active imaging system with Faraday filter

    DOEpatents

    Snyder, James J.

    1993-01-01

    An active imaging system has a low to medium powered laser transmitter and receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination while eliminating solar background.

  4. Inertial Confinement fusion targets

    NASA Technical Reports Server (NTRS)

    Hendricks, C. D.

    1982-01-01

    Inertial confinement fusion (ICF) targets are made as simple flat discs, as hollow shells or as complicated multilayer structures. Many techniques were devised for producing the targets. Glass and metal shells are made by using drop and bubble techniques. Solid hydrogen shells are also produced by adapting old methods to the solution of modern problems. Some of these techniques, problems, and solutions are discussed. In addition, the applications of many of the techniques to fabrication of ICF targets is presented.

  5. Confined Vortex Scrubber

    SciTech Connect

    Not Available

    1990-02-01

    The program objective is to demonstrate efficient removal of fine particulates to sufficiently low levels to meet proposed small scale coal combustor emission standards. This is to be accomplished using a novel particulate removal device, the Confined Vortex Scrubber. This is the first quarterly technical progress report under this contract. Accordingly, a summary of the cleanup concept and the structure of the program is given here.

  6. Energy confinement in tokamaks

    SciTech Connect

    Sugihara, M.; Singer, C.

    1986-08-01

    A straightforward generalization is made of the ohmic heating energy confinement scalings of Pfeiffer and Waltz and Blackwell et. al. The resulting model is systematically calibrated to published data from limiter tokamaks with ohmic, electron cyclotron, and neutral beam heating. With considerably fewer explicitly adjustable free parameters, this model appears to give a better fit to the available data for limiter discharges than the combined ohmic/auxiliary heating model of Goldston.

  7. Freezing in confined geometries

    NASA Technical Reports Server (NTRS)

    Sokol, P. E.; Ma, W. J.; Herwig, K. W.; Snow, W. M.; Wang, Y.; Koplik, Joel; Banavar, Jayanth R.

    1992-01-01

    Results of detailed structural studies, using elastic neutron scattering, of the freezing of liquid O2 and D2 in porous vycor glass, are presented. The experimental studies have been complemented by computer simulations of the dynamics of freezing of a Lennard-Jones liquid in narrow channels bounded by molecular walls. Results point to a new simple physical interpretation of freezing in confined geometries.

  8. System for objective assessment of fetal activity.

    PubMed

    Kaluzynski, K J; Kret, T; Czajkowski, K; Sieńko, J; Zmigrodzki, J

    2011-07-01

    Fetal activity is an important indicator of fetal well-being. It is proposed to assess this activity using the pulsed wave Doppler method to collect fetal activity data and dedicated software for on-line processing. The system, addressed to 3rd trimester pregnancies, provides information on presence of pseudobreathing, the heart rate trace, the fetal movement trace, the movement velocity spectrogram, histograms of the velocity and acceleration of both the body movements and pseudobreathing, parameters of these histograms (mean values, standard deviations, shape descriptors), and cumulative counts of the velocity histograms. These parameters form the feature vector of the fetal activity. The system was validated by simultaneous echographic and cardiotocographic recordings and during oxytocin challenge tests. Feature vectors obtained from 1h recordings in 61 pregnancies were submitted to multivariate analysis of variance. Activity patterns of physiological cases and "borderline pathologies" were discriminated using reduced feature vectors, containing cumulative counts of velocity histograms. PMID:21277248

  9. Active containment systems incorporating modified pillared clays

    SciTech Connect

    Lundie, P. |; McLeod, N.

    1997-12-31

    The application of treatment technologies in active containment systems provides a more advanced and effective method for the remediation of contaminated sites. These treatment technologies can be applied in permeable reactive walls and/or funnel and gate systems. The application of modified pillared clays in active containment systems provides a mechanism for producing permeable reactive walls with versatile properties. These pillared clays are suitably modified to incorporate reactive intercalatants capable of reacting with both a broad range of organic pollutants of varying molecular size, polarity and reactivity. Heavy metals can be removed from contaminated water by conventional ion-exchange and other reactive processes within the clay structure. Complex contamination problems can be addressed by the application of more than one modified clay on a site specific basis. This paper briefly describes the active containment system and the structure/chemistry of the modified pillared clay technology, illustrating potential applications of the in-situ treatment process for contaminated site remediation.

  10. High-Performance of Gas Hydrates in Confined Nanospace for Reversible CH4 /CO2 Storage.

    PubMed

    Casco, Mirian E; Jordá, José L; Rey, Fernando; Fauth, François; Martinez-Escandell, Manuel; Rodríguez-Reinoso, Francisco; Ramos-Fernández, Enrique V; Silvestre-Albero, Joaquín

    2016-07-11

    The molecular exchange of CH4 for CO2 in gas hydrates grown in confined nanospace has been evaluated for the first time using activated carbons as a host structure. The nano-confinement effects taking place inside the carbon cavities and the exceptional physicochemical properties of the carbon structure allows us to accelerate the formation and decomposition process of the gas hydrates from the conventional timescale of hours/days in artificial bulk systems to minutes in confined nanospace. The CH4 /CO2 exchange process is fully reversible with high efficiency at practical temperature and pressure conditions. Furthermore, these activated carbons can be envisaged as promising materials for long-distance natural gas and CO2 transportation because of the combination of a high storage capacity, a high reversibility, and most important, with extremely fast kinetics for gas hydrate formation and release. PMID:27273454

  11. Compounding effects of fluid confinement and surface strain on the wet–dry transition, thermodynamic response, and dynamics of water–graphene systems

    DOE PAGESBeta

    Chialvo, Ariel A.; Vlcek, Lukas; Cummings, Peter T.

    2015-01-01

    We studied the link between the water-mediated (tensile or compressive) strain-driven hydration free energy changes in the association process involving finite-size graphene surfaces, the resulting water-graphene interfacial behavior, and the combined effect of surface strain and fluid confinement on the thermodynamic response functions and the dynamics of water. In this study, we found that either small surface corrugation (compressive strain) or surface stretching (tensile strain) is able to enhance significantly the water-graphene hydrophobicity relative to that of the unstrained surface, an effect that exacerbates the confinement impact on the isothermal compressibility and isobaric thermal expansivity of confined water, as wellmore » as on the slowing down of its dynamics that gives rise to anomalous diffusivity.« less

  12. Compounding effects of fluid confinement and surface strain on the wet–dry transition, thermodynamic response, and dynamics of water–graphene systems

    SciTech Connect

    Chialvo, Ariel A.; Vlcek, Lukas; Cummings, Peter T.

    2015-01-01

    We studied the link between the water-mediated (tensile or compressive) strain-driven hydration free energy changes in the association process involving finite-size graphene surfaces, the resulting water-graphene interfacial behavior, and the combined effect of surface strain and fluid confinement on the thermodynamic response functions and the dynamics of water. In this study, we found that either small surface corrugation (compressive strain) or surface stretching (tensile strain) is able to enhance significantly the water-graphene hydrophobicity relative to that of the unstrained surface, an effect that exacerbates the confinement impact on the isothermal compressibility and isobaric thermal expansivity of confined water, as well as on the slowing down of its dynamics that gives rise to anomalous diffusivity.

  13. Compounding effects of fluid confinement and surface strain on the wet-dry transition, thermodynamic response, and dynamics of water-graphene systems

    NASA Astrophysics Data System (ADS)

    Chialvo, Ariel A.; Vlcek, Lukas; Cummings, Peter T.

    2015-05-01

    We studied the link between the water-mediated (tensile or compressive) strain-driven hydration free energy changes in the association process involving finite-size graphene surfaces, the resulting water-graphene interfacial behaviour, and the combined effect of surface strain and fluid confinement on the thermodynamic response functions and the dynamics of water. We found that either small surface corrugation (compressive strain) or surface stretching (tensile strain) is able to enhance significantly the water-graphene hydrophobicity relative to that of the unstrained surface, an effect that exacerbates the confinement impact on the isothermal compressibility and isobaric thermal expansivity of confined water, as well as on the slowdown of its dynamics that gives rise to anomalous diffusivity.

  14. Protection of Active Distribution Systems with DGs

    NASA Astrophysics Data System (ADS)

    Akila, Abdelrahman Ahmed; Helal, Ahmed; Eldesouki, Hussein

    2015-10-01

    Distribution systems are traditionally designed as radial passive systems fed from a single source. Protection coordination of such systems has been easily established assuming the system radiality. Insertion of distributed generators (DGs) into distribution systems makes the distribution system to be more active which causes redistribution of fault currents magnitudes and directions. This causes negative impacts on the original protection system coordination, since the distribution system losses its radiality and passiveness. Recently protection coordination in the presence of distributed generation has been paid a great attention. Researchers proposed various solutions to solve the protection coordination problem caused by adding DG into the distribution network. In this paper, the proposed solutions for the protection coordination problem considering the DG insertion will be illustrated, classified, and criticized.

  15. Dolomitization of the Lower Ordovician Prairie du Chien Group in southern Wisconsin and southeastern Minnesota: A case for confined and unconfined aquifer systems

    SciTech Connect

    Smith, G.L. )

    1990-05-01

    The Lower Ordovician Prairie du Chien Group overlies the Cambrian-Ordovician Jordan Formation and underlies the Middle Ordovician St Peter Formation. The Prairie du Chien Group contains the Oneota Formation and the New Richmond and Willow River Members of the Shakopee Formation. The Prairie du Chien Group and associated formations form a repetitive sequence of alternating dolomites and sandstones: Jordan (sand), Oneota (dolomite), New Richmond (sand/dolomite), Willow River (dolomite), St. Peter (sand), and Platteville/Galena (dolomite/limestone). Prairie du Chien and Platteville/Galena carbonates thin over the Wisconsin arch and thicken eastward and westward. Petrography, cathodoluminescence, and electron microprobe analysis were used to identify and differentiate dolomite zones. The Oneota contains dolomite zones 1 to 3; the Shakopee contains zones 2 and 3; the Platteville/Galena only contains zone 3. Electron microprobe analysis of zone 3 reveals systematic decreases in dolomite stoichiometry and increases in iron and manganese trace-element composition along a transect from the Wisconsin arch to southeastern Minnesota. Zone 3 probably precipitated within a confined aquifer with recharge on the Wisconsin arch and flow toward southeastern Minnesota. In analogous modern systems, pore waters become progressively more reducing downflow, favoring trace-element enrichment. Zone 2 dolomites have low, uniform iron and manganese contents and uniform stoichiometries. Zone 2 compositions are consistent with precipitation in an unconfined and/or well-mixed aquifer associated with a continent-wide pre-St. Peter sea level drawdown and paleokarsting. Trace-element distributions within zone 1 dolomites are intermediate, suggesting precipitation within a semiconfined aquifer during pre-New Richmond exposure.

  16. Aging assessment for active fire protection systems

    SciTech Connect

    Ross, S.B.; Nowlen, S.P.; Tanaka, T.

    1995-06-01

    This study assessed the impact of aging on the performance and reliability of active fire protection systems including both fixed fire suppression and fixed fire detection systems. The experience base shows that most nuclear power plants have an aggressive maintenance and testing program and are finding degraded fire protection system components before a failure occurs. Also, from the data reviewed it is clear that the risk impact of fire protection system aging is low. However, it is assumed that a more aggressive maintenance and testing program involving preventive diagnostics may reduce the risk impact even further.

  17. Active Displacement Control of Active Magnetic Bearing System

    NASA Astrophysics Data System (ADS)

    Kertész, Milan; Kozakovič, Radko; Magdolen, Luboš; Masaryk, Michal

    2014-12-01

    The worldwide energy production nowadays is over 3400 GW while storage systems have a capacity of only 90 GW [1]. There is a good solution for additional storage capacity in flywheel energy storage systems (FES). The main advantage of FES is its relatively high efficiency especially with using the active magnetic bearing system. Therefore there exist good reasons for appropriate simulations and for creating a suitable magneto-structural control system. The magnetic bearing, including actuation, is simulated in the ANSYS parametric design language (APDL). APDL is used to create the loops of transient simulations where boundary conditions (BC) are updated based upon a "gap sensor" which controls the nodal position values of the centroid of the shaft and the current density inputs onto the copper windings.

  18. Reactions over catalysts confined in carbon nanotubes.

    PubMed

    Pan, Xiulian; Bao, Xinhe

    2008-12-21

    We review a new concept for modifying the redox properties of transition metals via confinement within the channels of carbon nanotubes (CNTs), and thus tuning their catalytic performance. Attention is also devoted to novel techniques for homogeneous dispersion of metal nanoparticles inside CNTs since these are essential for optimization of the catalytic activity. PMID:19048128

  19. Neutral Beam Ion Confinement in NSTX

    SciTech Connect

    D.S. Darrow; E.D. Fredrickson; S.M. Kaye; S.S. Medley; and A.L. Roquemore

    2001-07-24

    Neutral-beam (NB) heating in the National Spherical Torus Experiment (NSTX) began in September 2000 using up to 5 MW of 80 keV deuterium (D) beams. An initial assessment of beam ion confinement has been made using neutron detectors, a neutral particle analyzer (NPA), and a Faraday cup beam ion loss probe. Preliminary neutron results indicate that confinement may be roughly classical in quiescent discharges, but the probe measurements do not match a classical loss model. MHD activity, especially reconnection events (REs) causes substantial disturbance of the beam ion population.

  20. Gamma Band Activity in the Reticular Activating System

    PubMed Central

    Urbano, Francisco J.; Kezunovic, Nebojsa; Hyde, James; Simon, Christen; Beck, Paige; Garcia-Rill, Edgar

    2012-01-01

    This review considers recent evidence showing that cells in three regions of the reticular activating system (RAS) exhibit gamma band activity, and describes the mechanisms behind such manifestation. Specifically, we discuss how cells in the mesopontine pedunculopontine nucleus (PPN), intralaminar parafascicular nucleus (Pf), and pontine subcoeruleus nucleus dorsalis (SubCD) all fire in the beta/gamma band range when maximally activated, but no higher. The mechanisms behind this ceiling effect have been recently elucidated. We describe recent findings showing that every cell in the PPN have high-threshold, voltage-dependent P/Q-type calcium channels that are essential, while N-type calcium channels are permissive, to gamma band activity. Every cell in the Pf also showed that P/Q-type and N-type calcium channels are responsible for this activity. On the other hand, every SubCD cell exhibited sodium-dependent subthreshold oscillations. A novel mechanism for sleep–wake control based on well-known transmitter interactions, electrical coupling, and gamma band activity is described. The data presented here on inherent gamma band activity demonstrates the global nature of sleep–wake oscillation that is orchestrated by brainstem–thalamic mechanism, and questions the undue importance given to the hypothalamus for regulation of sleep–wakefulness. The discovery of gamma band activity in the RAS follows recent reports of such activity in other subcortical regions like the hippocampus and cerebellum. We hypothesize that, rather than participating in the temporal binding of sensory events as seen in the cortex, gamma band activity manifested in the RAS may help stabilize coherence related to arousal, providing a stable activation state during waking and paradoxical sleep. Most of our thoughts and actions are driven by pre-conscious processes. We speculate that continuous sensory input will induce gamma band activity in the RAS that could participate in the processes of

  1. Shear Relaxations of Confined Liquids.

    NASA Astrophysics Data System (ADS)

    Carson, George Amos, Jr.

    Ultrathin (<40 A) films of octamethylcyclotetrasiloxane (OMCTS), hexadecane, and dodecane were subjected to linear and non-linear oscillatory shear between flat plates. Shearing frequencies of 0.1 to 800 s^{-1} were applied at pressures from zero to 0.8 MPa using a surface rheometer only recently developed. In most cases the plates were atomically smooth mica surfaces; the role of surface interactions was examined by replacing these with alkyl chain monolayers. OMCTS and hexadecane were examined at a temperature about 5 Celsius degrees above their melting points and tended to solidify. Newtonian plateaus having enormous viscosities were observed at low shear rates. The onset of shear thinning implied relaxation times of about 0.1 s in the linear structure of the confined liquids. Large activation volumes (~80 nm ^3) suggested that shear involved large-scale collective motion. Dodecane was studied at a much higher temperature relative to its melting point and showed no signs of impending solidification though it exhibited well-defined regions of Newtonian response and power law shear thinning. When treated with molecular sieves before use, dodecane had relaxation times which were short (0.02 s) compared to hexadecane, but still exhibited large-scale collective motion. When treated with silica gel, an unexplained long -time relaxation (10 s) was seen in the Newtonian viscosity of dodecane. The relaxation time of the linear structure, 0.005 s was very small, and the storage modulus was unresolvable. The small activation volume (7nm^3) indicated a much lower level of collective motion. The activation volume remained small when dodecane was confined between tightly bound, low energy, alkyl monolayers. At low strains the storage and loss moduli became very large (>10^4 Pa), probably due to interactions with flaws in the monolayers. Dramatic signs of wall slip were observed at large strains even at low pressures.

  2. Shear relaxations of confined liquids

    SciTech Connect

    Carson, G.A. Jr.

    1992-01-01

    Ultrathin (<40 [angstrom]) films of octamethylcyclotetrasiloxane (OMCTS), hexadecane, and dodecane were subjected to linear and non-linear oscillatory shear between flat plates. Shearing frequencies of 0.1 to 800 s[sup [minus]1] were applied at pressures from zero to 0.8 MPa using a surface rheometer only recently developed. In most cases the plates were atomically smooth mica surfaces; the role of surface interactions was examined by replacing these with alkyl chain monolayers. OMCTS and hexadecane were examined at a temperature about 5 Celcius degrees above their melting points and tended to solidify. Newtonian plateaus having enormous viscosities were observed at low shear rates. The onset of shear thinning implied relaxation times of about 0.1 s in the linear structure of the confined liquids. Large activation volumes ([approximately]80 nm[sup 3]) suggested that shear involved large-scale collective motion. Dodecane was studied at a much higher temperature relative to its melting point and showed no signs of impending solidification though it exhibited well-defined regions of Newtonian response and power law shear thinning. When treated with molecular sieves before use, dodecane had relaxation times which were short (0.02 s) compared to hexadecane, but still exhibited large-scale collective motion. When treated with silica gel, an unexplained long-time relaxation (10 s) was seen in the Newtonian viscosity of dodecane. The relaxation time of the linear structure, 0.005 s was very small, and the storage modulus was unresolvable. The small activation volume (7 nm[sup 3]) indicated a much lower level of collective motion. The activation volume remained small when dodecane was confined between tightly bound, low energy, alkyl monolayers. At low strains the storage and loss moduli became very large (>10[sup 4] Pa), probably due to interactions with flaws in the monolayers. Dramatic signs of wall slip were observed at large strains even at low pressures.

  3. Confined vortex scrubber

    SciTech Connect

    Not Available

    1990-07-01

    The program objective is to demonstrate efficient removal of fine particulates to sufficiently low levels to meet proposed small scale coal combustor emission standards using a cleanup technology appropriate to small scale coal combustors. This to be accomplished using a novel particulate removal device, the Confined Vortex Scrubber (CVS), which consists of a cylindrical vortex chamber with tangential flue gas inlets. The clean gas exit is via vortex finder outlets, one at either end of the tube. Liquid is introduced into the chamber and is confined within the vortex chamber by the centrifugal force generated by the gas flow itself. This confined liquid forms a layer through which the flue gas is then forced to bubble, producing a strong gas/liquid interaction, high inertial separation forces and efficient particulate cleanup. During this quarter a comprehensive series of cleanup experiments have been made for three CVS configurations. The first CVS configuration tested gave very efficient fine particulate removal at the design air mass flow rate (1 MM BUT/hr combustor exhaust flow), but had over 20{double prime}WC pressure drop. The first CVS configuration was then re-designed to produce the same very efficient particulate collection performance at a lower pressure drop. The current CVS configuration produces 99.4 percent cleanup of ultra-fine fly ash at the design air mass flow at a pressure drop of 12 {double prime}WC with a liquid/air flow ratio of 0.31/m{sup 3}. Unlike venturi scrubbers, the collection performance of the CVS is insensitive to dust loading and to liquid/air flow ratio.

  4. Traveling and Resting Crystals in Active Systems

    NASA Astrophysics Data System (ADS)

    Menzel, Andreas M.; Löwen, Hartmut

    2013-02-01

    A microscopic field theory for crystallization in active systems is proposed which unifies the phase-field-crystal model of freezing with the Toner—Tu theory for self-propelled particles. A wealth of different active crystalline states are predicted and characterized. In particular, for increasing strength of self-propulsion, a transition from a resting crystal to a traveling crystalline state is found where the particles migrate collectively while keeping their crystalline order. Our predictions, which are verifiable in experiments and in particle-resolved computer simulations, provide a starting point for the design of new active materials.

  5. Are polymers glassier upon confinement?

    NASA Astrophysics Data System (ADS)

    Napolitano, Simone; Spiece, Jean; Martinez-Tong, Daniel E.; Sferrazza, Michele; Nogales, Aurora

    Glass forming systems are characterized by a stability against crystallization upon heating and by the easiness with which their liquid phase can be transformed into a solid lacking of long-range order upon cooling (glass forming ability). Here, we discuss on the the thickness dependence of the thermal phase transition temperatures of poly(L-lactide acid) thin films supported onto solid substrates. The determination of the glass transition (Tg), cold crystallization (TCC) and melting (Tm) temperatures down to a thickness of 6 nm via ellipsometry, permitted us to build up parameters describing glass stability and glass forming ability. We observed a strong influence of the film thickness on the latter, while the former is not affected by 1D confinement. Remarkably, the increase in Tg/Tm ratio, a parameter related to glass forming ability, is not accompanied by an increase in TCC-Tg, as observed on the contrary, in bulk metallic glasses. We explained this peculiar behavior of soft matter in confinement considering the impact of irreversible adsorption on local free volume content.

  6. Soft confinement for polymer solutions

    NASA Astrophysics Data System (ADS)

    Oya, Yutaka; Kawakatsu, Toshihiro

    2014-07-01

    As a model of soft confinement for polymers, we investigated equilibrium shapes of a flexible vesicle that contains a phase-separating polymer solution. To simulate such a system, we combined the phase field theory (PFT) for the vesicle and the self-consistent field theory (SCFT) for the polymer solution. We observed a transition from a symmetric prolate shape of the vesicle to an asymmetric pear shape induced by the domain structure of the enclosed polymer solution. Moreover, when a non-zero spontaneous curvature of the vesicle is introduced, a re-entrant transition between the prolate and the dumbbell shapes of the vesicle is observed. This re-entrant transition is explained by considering the competition between the loss of conformational entropy and that of translational entropy of polymer chains due to the confinement by the deformable vesicle. This finding is in accordance with the recent experimental result reported by Terasawa et al. (Proc. Natl. Acad. Sci. U.S.A., 108 (2011) 5249).

  7. Confined Space Imager (CSI) Software

    2013-07-03

    The software provides real-time image capture, enhancement, and display, and sensor control for the Confined Space Imager (CSI) sensor system The software captures images over a Cameralink connection and provides the following image enhancements: camera pixel to pixel non-uniformity correction, optical distortion correction, image registration and averaging, and illumination non-uniformity correction. The software communicates with the custom CSI hardware over USB to control sensor parameters and is capable of saving enhanced sensor images to anmore » external USB drive. The software provides sensor control, image capture, enhancement, and display for the CSI sensor system. It is designed to work with the custom hardware.« less

  8. Confinement Contains Condensates

    SciTech Connect

    Brodsky, Stanley J.; Roberts, Craig D.; Shrock, Robert; Tandy, Peter C.

    2012-03-12

    Dynamical chiral symmetry breaking and its connection to the generation of hadron masses has historically been viewed as a vacuum phenomenon. We argue that confinement makes such a position untenable. If quark-hadron duality is a reality in QCD, then condensates, those quantities that have commonly been viewed as constant empirical mass-scales that fill all spacetime, are instead wholly contained within hadrons; i.e., they are a property of hadrons themselves and expressed, e.g., in their Bethe-Salpeter or light-front wave functions. We explain that this paradigm is consistent with empirical evidence, and incidentally expose misconceptions in a recent Comment.

  9. Confinement Vessel Dynamic Analysis

    SciTech Connect

    R. Robert Stevens; Stephen P. Rojas

    1999-08-01

    A series of hydrodynamic and structural analyses of a spherical confinement vessel has been performed. The analyses used a hydrodynamic code to estimate the dynamic blast pressures at the vessel's internal surfaces caused by the detonation of a mass of high explosive, then used those blast pressures as applied loads in an explicit finite element model to simulate the vessel's structural response. Numerous load cases were considered. Particular attention was paid to the bolted port connections and the O-ring pressure seals. The analysis methods and results are discussed, and comparisons to experimental results are made.

  10. Admissible release from the chernobyl new safe confinement

    SciTech Connect

    Batiy, Valeriy; Paskevych, Sergei; Rudko, Vladimir; Sizov, Andrey; Shcherbin, Vladimir; Schmieman, Eric A.

    2005-08-08

    Calculation of admissible releases at different exploitation stages of New Safe Confinement at the existing ChNPP ''Shelter'' object are given. Vain conclusions of calculations are given as well as recommendations for planning of activities connected with the New Safe Confinement construction.

  11. Inhibited emission of electromagnetic modes confined in subwavelength cavities

    SciTech Connect

    Le Thomas, N.; Houdre, R.

    2011-07-15

    We experimentally demonstrate the active inhibition of subwavelength confined cavity modes emission and quality factor enhancement by controlling the cavity optical surrounding. The intrinsic radiation angular spectrum of modes confined in planar photonics crystal cavities as well as its modifications depending on the environment are inferred via a transfer matrix modeling and k-space imaging.

  12. Distributed control system for active mirrors

    NASA Astrophysics Data System (ADS)

    Rodriguez-Ramos, Luis F.; Williams, Mark R.; Castro, Javier; Cruz, A.; Gonzalez, Juan C.; Mack, Brian; Martin, Carlos; Pescador, German; Sanchez, Vicente; Sosa, Nicolas A.

    1994-06-01

    This paper presents the IAC (Instituto de Astrofisica de Canaries, Spain) proposal of a distributed control system intended for the active support of a 8 m mirror. The system incorporates a large number of compact `smart' force actuators, six force definers, and a mirror support computer (MSC) for interfacing with the telescope control system and for general housekeeping. We propose the use of a network for the interconnection of the actuators, definers and the MSC, which will minimize the physical complexity of the interface between the mirror support system and the MSC. The force actuator control electronics are described in detail, as is the system software architecture of the actuator and the MSC. As the network is a key point for the system, we also detail the evaluation of three candidates, before electing the CAN bus.

  13. A method to estimate groundwater depletion from confining layers

    USGS Publications Warehouse

    Konikow, L.F.; Neuzil, C.E.

    2007-01-01

    Although depletion of storage in low-permeability confining layers is the source of much of the groundwater produced from many confined aquifer systems, it is all too frequently overlooked or ignored. This makes effective management of groundwater resources difficult by masking how much water has been derived from storage and, in some cases, the total amount of water that has been extracted from an aquifer system. Analyzing confining layer storage is viewed as troublesome because of the additional computational burden and because the hydraulic properties of confining layers are poorly known. In this paper we propose a simplified method for computing estimates of confining layer depletion, as well as procedures for approximating confining layer hydraulic conductivity (K) and specific storage (Ss) using geologic information. The latter makes the technique useful in developing countries and other settings where minimal data are available or when scoping calculations are needed. As such, our approach may be helpful for estimating the global transfer of groundwater to surface water. A test of the method on a synthetic system suggests that the computational errors will generally be small. Larger errors will probably result from inaccuracy in confining layer property estimates, but these may be no greater than errors in more sophisticated analyses. The technique is demonstrated by application to two aquifer systems: the Dakota artesian aquifer system in South Dakota and the coastal plain aquifer system in Virginia. In both cases, depletion from confining layers was substantially larger than depletion from the aquifers.

  14. Modular System to Enable Extravehicular Activity

    NASA Technical Reports Server (NTRS)

    Sargusingh, Miriam J.

    2011-01-01

    The ability to perform extravehicular activity (EVA), both human and robotic, has been identified as a key component to space missions to support such operations as assembly and maintenance of space system (e.g. construction and maintenance of the International Space Station), and unscheduled activities to repair an element of the transportation and habitation systems that can only be accessed externally and via unpressurized areas. In order to make human transportation beyond lower earth orbit (BLEO) practical, efficiencies must be incorporated into the integrated transportation systems to reduce system mass and operational complexity. Affordability is also a key aspect to be considered in space system development; this could be achieved through commonality, modularity and component reuse. Another key aspect identified for the EVA system was the ability to produce flight worthy hardware quickly to support early missions and near Earth technology demonstrations. This paper details a conceptual architecture for a modular extravehicular activity system (MEVAS) that would meet these stated needs for EVA capability that is affordable, and that could be produced relatively quickly. Operational concepts were developed to elaborate on the defined needs and define the key capabilities, operational and design constraints, and general timelines. The operational concept lead to a high level design concept for a module that interfaces with various space transportation elements and contains the hardware and systems required to support human and telerobotic EVA; the module would not be self-propelled and would rely on an interfacing element for consumable resources. The conceptual architecture was then compared to EVA Systems used in the Shuttle Orbiter, on the International Space Station to develop high level design concepts that incorporate opportunities for cost savings through hardware reuse, and quick production through the use of existing technologies and hardware designs

  15. Active Annuloplasty System for Mitral Valve Insufficiency

    NASA Astrophysics Data System (ADS)

    Díaz Lantada, Andrés; Lafont, Pilar; Rada, Ignacio; Jiménez, Antonio; Hernández, José Luis; Lorenzo-Yustos, Héctor; Muñoz-García, Julio

    Active materials are capable of responding in a controlled way to different external physical or chemical stimuli by changing some of their properties. These materials can be used to design and develop sensors, actuators and multifunctional systems with a large number of applications for developing medical devices.

  16. METALS DISTRIBUTIONS IN ACTIVATED SLUDGE SYSTEMS

    EPA Science Inventory

    This project developed models to predict the distribution of metals in activated sludge system process streams. The data used to develop the models were obtained through extended pilot studies from a previous project. The objectives of the study were to evaluate the effects of wa...

  17. Supporting Classroom Activities with the BSUL System

    ERIC Educational Resources Information Center

    Ogata, Hiroaki; Saito, Nobuji A.; Paredes J., Rosa G.; San Martin, Gerardo Ayala; Yano, Yoneo

    2008-01-01

    This paper presents the integration of ubiquitous computing systems into classroom settings, in order to provide basic support for classrooms and field activities. We have developed web application components using Java technology and configured a classroom with wireless network access and a web camera for our purposes. In this classroom, the…

  18. Design of nutrient removal activated sludge systems.

    PubMed

    Manga, J; Ferrer, J; Seco, A; Garcia-Usach, F

    2003-01-01

    A mechanistic mathematical model for nutrient and organic matter removal was used to describe the behavior of a nitrification denitrification enhanced biological phosphorus removal (NDEBPR) system. This model was implemented in a user-friendly software DESASS (design and simulation of activated sludge systems). A 484-L pilot plant was operated to verify the model results. The pilot plant was operated for three years over three different sludge ages. The validity of the model was confirmed with data from the pilot plant. Also, the utility of DESASS as a valuable tool for designing NDEBPR systems was confirmed. PMID:12906279

  19. Targeted activation in deterministic and stochastic systems

    NASA Astrophysics Data System (ADS)

    Eisenhower, Bryan; Mezić, Igor

    2010-02-01

    Metastable escape is ubiquitous in many physical systems and is becoming a concern in engineering design as these designs (e.g., swarms of vehicles, coupled building energetics, nanoengineering, etc.) become more inspired by dynamics of biological, molecular and other natural systems. In light of this, we study a chain of coupled bistable oscillators which has two global conformations and we investigate how specialized or targeted disturbance is funneled in an inverse energy cascade and ultimately influences the transition process between the conformations. We derive a multiphase averaged approximation to these dynamics which illustrates the influence of actions in modal coordinates on the coarse behavior of this process. An activation condition that predicts how the disturbance influences the rate of transition is then derived. The prediction tools are derived for deterministic dynamics and we also present analogous behavior in the stochastic setting and show a divergence from Kramers activation behavior under targeted activation conditions.

  20. Green Bank Telescope active surface system

    NASA Astrophysics Data System (ADS)

    Lacasse, Richard J.

    1998-05-01

    During the design phase of the Green Bank Telescope (GBT), various means of providing an accurate surface on a large aperture paraboloid, were considered. Automated jacks supporting the primary reflector were selected as the appropriate technology since they promised greater performance and potentially lower costs than a homologous or carbon fiber design, and had certain advantages over an active secondary. The design of the active surface has presented many challenges. Since the actuators are mounted on a tipping structure, it was required that they support a significant side-load. Such devices were not readily available commercially so they had to be developed. Additional actuator requirements include low backlash, repeatable positioning, and an operational life of at least 230 years. Similarly, no control system capable of controlling the 2209 actuators was commercially available. Again a prime requirement was reliability. Maintaining was also a very important consideration. The system architecture is tree-like. An active surface 'master-computer' controls interaction with the telescope control system, and controls ancillary equipment such as power supplies and temperature monitors. Two slave computers interface with the master- computer, and each closes approximately 1100 position loops. For simplicity, the servo is an 'on/off' type, yet achieves a positioning resolution of 25 microns. Each slave computer interfaces with 4 VME I/O cards, which in turn communicate with 140 control modules. The control modules read out the positions of the actuators every 0.1 sec and control the actuators' DC motors. Initial control of the active surface will be based on an elevation dependant structural model. Later, the model will be improved by holographic observations.Surface accuracy will be improved further by using laser ranging system which will actively measure the surface figure. Several tests have been conducted to assure that the system will perform as desired when

  1. National Ignition Facility for Inertial Confinement Fusion

    SciTech Connect

    Paisner, J.A.; Murray, J.R.

    1997-10-08

    The National Ignition Facility for inertial confinement fusion will contain a 1.8 MJ, 500 TW frequency-tripled neodymium glass laser system that will be used to explore fusion ignition and other problems in the physics of high temperature and density. We describe the facility briefly. The NIF is scheduled to be completed in 2003.

  2. Active gated imaging in driver assistance system

    NASA Astrophysics Data System (ADS)

    Grauer, Yoav

    2014-04-01

    In this paper, we shall present the active gated imaging system (AGIS) in relation to the automotive field. AGIS is based on a fast-gated camera and pulsed illuminator, synchronized in the time domain to record images of a certain range of interest. A dedicated gated CMOS imager sensor and near infra-red (NIR) pulsed laser illuminator, is presented in this paper to provide active gated technology. In recent years, we have developed these key components and learned the system parameters, which are most beneficial to nighttime (in all weather conditions) driving in terms of field of view, illumination profile, resolution, and processing power. We shall present our approach of a camera-based advanced driver assistance systems (ADAS) named BrightEye™, which makes use of the AGIS technology in the automotive field.

  3. Special issue containing papers presented at the 12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (7-11 September 2011) Special issue containing papers presented at the 12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (7-11 September 2011)

    NASA Astrophysics Data System (ADS)

    Berk, H. L.

    2012-09-01

    The topic of the behaviour of energetic alpha particles in magnetic fusion confined plasmas is perhaps the ultimate frontier plasma physics issue that needs to be understood in the quest to achieve controlled power from the fusion reaction in magnetically confined plasmas. The partial pressure of alpha particles in a burning plasma will be ~5-10% of the total pressure and under these conditions the alpha particles may be prone to develop instability through Alfvénic interaction. This may lead, even with moderate alpha particle loss, to a burn quench or severe wall damage. Alternatively, benign Alfvénic signals may allow the vital information to control a fusion burn. The significance of this issue has led to extensive international investigations and a biannual meeting that began in Kyiv in 1989, followed by subsequent meetings in Aspenäs (1991), Trieste (1993), Princeton (1995), JET/Abingdon (1997), Naka (1999), Gothenburg (2001), San Diego (2003), Takayama (2005), Kloster Seeon (2007) and Kyiv (2009). The meeting was initially entitled 'Alpha Particles in Fusion Research' and then was changed during the 1997 meeting to 'Energetic Particles in Magnetic Confinement Systems' in appreciation of the need to study the significance of the electron runaway, which can lead to the production of energetic electrons with energies that can even exceed the energy produced by fusion products. This special issue presents some of the mature interesting work that was reported at the 12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems, which was held in Austin, Texas, USA (7-11 September 2011). This meeting immediately followed a related meeting, the 5th IAEA Technical Meeting on Theory of Plasma Wave Instabilities (5-7 September 2011). The meetings shared one day (7 September 2011) with presentations relevant to both groups. The presentations from most of the participants, as well as some preliminary versions of papers, are available at the

  4. Amoeboid motion in confined geometry

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Thiébaud, M.; Hu, W.-F.; Farutin, A.; Rafaï, S.; Lai, M.-C.; Peyla, P.; Misbah, C.

    2015-11-01

    Many eukaryotic cells undergo frequent shape changes (described as amoeboid motion) that enable them to move forward. We investigate the effect of confinement on a minimal model of amoeboid swimmer. A complex picture emerges: (i) The swimmer's nature (i.e., either pusher or puller) can be modified by confinement, thus suggesting that this is not an intrinsic property of the swimmer. This swimming nature transition stems from intricate internal degrees of freedom of membrane deformation. (ii) The swimming speed might increase with increasing confinement before decreasing again for stronger confinements. (iii) A straight amoeoboid swimmer's trajectory in the channel can become unstable, and ample lateral excursions of the swimmer prevail. This happens for both pusher- and puller-type swimmers. For weak confinement, these excursions are symmetric, while they become asymmetric at stronger confinement, whereby the swimmer is located closer to one of the two walls. In this study, we combine numerical and theoretical analyses.

  5. Are polymers glassier upon confinement?

    PubMed

    Spièce, Jean; Martínez-Tong, Daniel E; Sferrazza, Michele; Nogales, Aurora; Napolitano, Simone

    2015-08-21

    Glass forming systems are characterized by a stability against crystallization upon heating and by the easiness with which their liquid phase can be transformed into a solid lacking of long-range order upon cooling (glass forming ability). Here, we report the thickness dependence of the thermal phase transition temperatures of poly(l-lactide acid) thin films supported onto solid substrates. The determination of the glass transition, cold crystallization and melting temperatures down to a thickness of 6 nm, permitted us to build up parameters describing glass stability and glass forming ability. We observed a strong influence of the film thickness on the latter, while the former is not affected by 1D confinement. Further experiments permitted us to highlight key structural morphology features giving insights to our ellipsometric results via a physical picture based on the changes in the free volume content in proximity of the supporting interfaces. PMID:26086889

  6. Modular System to Enable Extravehicular Activity

    NASA Technical Reports Server (NTRS)

    Sargusingh, Miriam J.

    2012-01-01

    The ability to perform extravehicular activity (EVA), both human and robotic, has been identified as a key component to space missions to support such operations as assembly and maintenance of space systems (e.g. construction and maintenance of the International Space Station), and unscheduled activities to repair an element of the transportation and habitation systems that can only be accessed externally and via unpressurized areas. In order to make human transportation beyond lower Earth orbit (LEO) practical, efficiencies must be incorporated into the integrated transportation systems to reduce system mass and operational complexity. Affordability is also a key aspect to be considered in space system development; this could be achieved through commonality, modularity and component reuse. Another key aspect identified for the EVA system was the ability to produce flight worthy hardware quickly to support early missions and near Earth technology demonstrations. This paper details a conceptual architecture for a modular EVA system that would meet these stated needs for EVA capability that is affordable, and that could be produced relatively quickly. Operational concepts were developed to elaborate on the defined needs, and to define the key capabilities, operational and design constraints, and general timelines. The operational concept lead to a high level design concept for a module that interfaces with various space transportation elements and contains the hardware and systems required to support human and telerobotic EVA; the module would not be self-propelled and would rely on an interfacing element for consumable resources. The conceptual architecture was then compared to EVA Systems used in the Space Shuttle Orbiter, on the International Space Station to develop high level design concepts that incorporate opportunities for cost savings through hardware reuse, and quick production through the use of existing technologies and hardware designs. An upgrade option

  7. Optically Active Porphyrin and Phthalocyanine Systems.

    PubMed

    Lu, Hua; Kobayashi, Nagao

    2016-05-25

    This review highlights and summarizes various optically active porphyrin and phthalocyanine molecules prepared using a wide range of structural modification methods to improve the design of novel structures and their applications. The induced chirality of some illustrative achiral bis-porphyrins with a chiral guest molecule is introduced because these systems are ideal for the identification and separation of chiral biologically active substrates. In addition, the relationship between CD signal and the absolute configuration of the molecule is analyzed through an analysis of the results of molecular modeling calculations. Possible future research directions are also discussed. PMID:27186902

  8. Deforming baryons into confining strings

    NASA Astrophysics Data System (ADS)

    Hartnoll, Sean A.; Portugues, Rubén

    2004-09-01

    We find explicit probe D3-brane solutions in the infrared of the Maldacena-Nuñez background. The solutions describe deformed baryon vertices: q external quarks are separated in spacetime from the remaining N-q. As the separation is taken to infinity we recover known solutions describing infinite confining strings in N=1 gauge theory. We present results for the mass of finite confining strings as a function of length. We also find probe D2-brane solutions in a confining type IIA geometry, the reduction of a G2 holonomy M theory background. The relation between these deformed baryons and confining strings is not as straightforward.

  9. Modelling the activation of a confined debris slide in Northern Calabria: the 28 January 2009 slope movement at San Benedetto Ullano

    NASA Astrophysics Data System (ADS)

    Capparelli, G.; Iaquinta, P.; Iovine, G.; Terranova, O.; Versace, P.

    2009-09-01

    Southern Italy was severely stricken by abundant rains during Autumn-Winter 2008/2009, with widespread geomorphic effects such as slope movements and erosive processes, floods, inundations of cultivated fields and urbanised sectors, and coastal instabilities. A large number of superficial landslides were triggered in Calabria up to the middle of January, damaging life lines, roads, urbanised areas and lands, mainly in the NW sector of the region. Further persistent rainfalls were recorded until the end of March, and several deeper phenomena also activated along the slopes threatening villages and main lifelines. More specifically, a large rainfall-induced debris slide started mobilizing on 28 January along the Eastern slope of the Coastal Chain, in the vicinity of San Benedetto Ullano (Cosenza province). The slope movement threatened the southern suburbs of the village, damaging the road to the cemetery and the provincial road to Marri. Thanks to a prompt detailed geomorphologic field survey (protracted for the entire period of activity), to recurrent hand-made measures of superficial displacements performed at a set of datum points by a team of volunteers, and a real-time control system of meteoric conditions and superficial displacements at a set of precision-extensometers, the evolution of the phenomenon was mapped up to the last days of April, when the movement practically stopped at the end of the rainy period. Based on the results of the above-mentioned control activities, a basic empirical reference framework of procedures could be defined, which allowed the Authorities concerned to better manage the phases of geo-hydrological crisis, by adopting suitable emergency measures. The preliminary geological model of the landslide and of the affected slope, which had to be defined in the first stages of mobilization based on the few available data, was progressively refined thanks to the results of a couple of explorative drillings, driven down to 40 meters below

  10. Control Systems Cyber Security Standards Support Activities

    SciTech Connect

    Robert Evans

    2009-01-01

    The Department of Homeland Security’s Control Systems Security Program (CSSP) is working with industry to secure critical infrastructure sectors from cyber intrusions that could compromise control systems. This document describes CSSP’s current activities with industry organizations in developing cyber security standards for control systems. In addition, it summarizes the standards work being conducted by organizations within the sector and provides a brief listing of sector meetings and conferences that might be of interest for each sector. Control systems cyber security standards are part of a rapidly changing environment. The participation of CSSP in the development effort for these standards has provided consistency in the technical content of the standards while ensuring that information developed by CSSP is included.

  11. Advanced extravehicular activity systems requirements definition study

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A study to define the requirements for advanced extravehicular activities (AEVA) was conducted. The purpose of the study was to develop an understanding of the EVA technology requirements and to map a pathway from existing or developing technologies to an AEVA system capable of supporting long-duration missions on the lunar surface. The parameters of an AEVA system which must sustain the crewmembers and permit productive work for long periods in the lunar environment were examined. A design reference mission (DRM) was formulated and used as a tool to develop and analyze the EVA systems technology aspects. Many operational and infrastructure design issues which have a significant influence on the EVA system are identified.

  12. Active State Model for Autonomous Systems

    NASA Technical Reports Server (NTRS)

    Park, Han; Chien, Steve; Zak, Michail; James, Mark; Mackey, Ryan; Fisher, Forest

    2003-01-01

    The concept of the active state model (ASM) is an architecture for the development of advanced integrated fault-detection-and-isolation (FDI) systems for robotic land vehicles, pilotless aircraft, exploratory spacecraft, or other complex engineering systems that will be capable of autonomous operation. An FDI system based on the ASM concept would not only provide traditional diagnostic capabilities, but also integrate the FDI system under a unified framework and provide mechanism for sharing of information between FDI subsystems to fully assess the overall health of the system. The ASM concept begins with definitions borrowed from psychology, wherein a system is regarded as active when it possesses self-image, self-awareness, and an ability to make decisions itself, such that it is able to perform purposeful motions and other transitions with some degree of autonomy from the environment. For an engineering system, self-image would manifest itself as the ability to determine nominal values of sensor data by use of a mathematical model of itself, and selfawareness would manifest itself as the ability to relate sensor data to their nominal values. The ASM for such a system may start with the closed-loop control dynamics that describe the evolution of state variables. As soon as this model was supplemented with nominal values of sensor data, it would possess self-image. The ability to process the current sensor data and compare them with the nominal values would represent self-awareness. On the basis of self-image and self-awareness, the ASM provides the capability for self-identification, detection of abnormalities, and self-diagnosis.

  13. Research on an Active Seat Belt System

    NASA Astrophysics Data System (ADS)

    Kawashima, Takeshi

    In a car crash, permanent injury can be avoided if deformation of an occupant's rib cage is maintained within the allowable value. In order to realize this condition, the occupant's seat belt tension must be instantaneously adjusted by a feedback control system. In this study, a seat belt tension control system based on the active shock control system is proposed. The semi-active control law used is derived from the sliding mode control method. One advantage of this proposed system is that it does not require a large power actuator because the seat belt tension is controlled by a brake mechanism. The effectiveness is confirmed by numerical simulation using general parameters of a human thorax and a passenger car in a collision scenario with a wall at a velocity of 100 km/h. The feasibility is then confirmed with a control experiment using a scale model of about 1/10 scale. The relative displacement of the thorax model approaches the allowable value smoothly along the control reference and settles near this value. Thus, the proposed seat belt tension control system design is established.

  14. Multipurpose active/passive motion compensation system

    SciTech Connect

    Sullivan, R.A.; Clements, R.E.; Davenport, M.R.

    1984-05-01

    A microprocessor-controlled active/passive motion compensation system has been developed for deploying a variety of geotechnical in-situ testing devices with mobile drilling rigs from low-cost service vessels. The light-weight rotary heave compensator incorporates a hydraulic motor as the compensator actuator and a servo-controlled closed loop pump to reduce the air storage and power requirements. Unique features of the system are the use of inertial sensors to measure three components of boat motion, the ability to run the system in active/passive or passive modes, and the ability to automatically lower the drillstring at a constant velocity while maintaining motion compensation. Quantitative measurements made during sea trials offshore California yielded motion compensation accuracy approaching 98 percent which is much better than the compensation achieved with passive systems. Results are presented from offshore in-situ testing with a cone penetrometer, a vane shear device, and a suspension PS logger. The system can also be used for other offshore applications.

  15. Active laser system for sea ice control

    NASA Astrophysics Data System (ADS)

    Evtikhiev, Nickolay N.; Gaponov, Alexandr E.; Kuluba, Yury N.; Matous, Vladislav I.; Radominov, Oleg E.; Tuzikov, Vladimir Z.; Vargaftic, Vasiliy N.

    1997-01-01

    The airborne systems are used for complex investigations of coastline very successfully, for example it can be used to measure the depth of the sea, to discover the reefs and so on. Such information may be used in navigation too. The specific conditions of navigation in the North and Pole seas defines the necessity of exact knowledge about the ice cracks in order to find the possible direction of the ship movement. The active optical system, working in the near IR region, has many advantages before the passive one, especially if it is necessary to work during the polar night and at bad weather conditions. In this article we discuss the demands to the laser active airborne systems, that given the accurate picture of the ice with high resolution in the daytime and nighttime conditions. Such system based on the laser, mechanical scanner and avalanche photodiode is very compact, reliable and informative. The picture of the ice surface can be shown on the TV monitor, can be written to the memory and can be delivered to the processing center by the radiochannel. The experimental results are shown together with results of this system probing in the conditions of the North Pole Ocean.

  16. PCM Passive Cooling System Containing Active Subsystems

    NASA Technical Reports Server (NTRS)

    Blanding, David E.; Bass, David I.

    2005-01-01

    A multistage system has been proposed for cooling a circulating fluid that is subject to intermittent intense heating. The system would be both flexible and redundant in that it could operate in a basic passive mode, either sequentially or simultaneously with operation of a first, active cooling subsystem, and either sequentially or simultaneously with a second cooling subsystem that could be active, passive, or a combination of both. This flexibility and redundancy, in combination with the passive nature of at least one of the modes of operation, would make the system more reliable, relative to a conventional cooling system. The system would include a tube-in-shell heat exchanger, within which the space between the tubes would be filled with a phase-change material (PCM). The circulating hot fluid would flow along the tubes in the heat exchanger. In the basic passive mode of operation, heat would be conducted from the hot fluid into the PCM, wherein the heat would be stored temporarily by virtue of the phase change.

  17. Active Aircraft Pylon Noise Control System

    NASA Technical Reports Server (NTRS)

    Thomas, Russell H. (Inventor); Czech, Michael J (Inventor); Elmiligui, Alaa A. (Inventor)

    2015-01-01

    An active pylon noise control system for an aircraft includes a pylon structure connecting an engine system with an airframe surface of the aircraft and having at least one aperture to supply a gas or fluid therethrough, an intake portion attached to the pylon structure to intake a gas or fluid, a regulator connected with the intake portion via a plurality of pipes, to regulate a pressure of the gas or fluid, a plenum chamber formed within the pylon structure and connected with the regulator, and configured to receive the gas or fluid as regulated by the regulator, and a plurality of injectors in communication with the plenum chamber to actively inject the gas or fluid through the plurality of apertures of the pylon structure.

  18. Spontaneous activity in the developing auditory system.

    PubMed

    Wang, Han Chin; Bergles, Dwight E

    2015-07-01

    Spontaneous electrical activity is a common feature of sensory systems during early development. This sensory-independent neuronal activity has been implicated in promoting their survival and maturation, as well as growth and refinement of their projections to yield circuits that can rapidly extract information about the external world. Periodic bursts of action potentials occur in auditory neurons of mammals before hearing onset. This activity is induced by inner hair cells (IHCs) within the developing cochlea, which establish functional connections with spiral ganglion neurons (SGNs) several weeks before they are capable of detecting external sounds. During this pre-hearing period, IHCs fire periodic bursts of Ca(2+) action potentials that excite SGNs, triggering brief but intense periods of activity that pass through auditory centers of the brain. Although spontaneous activity requires input from IHCs, there is ongoing debate about whether IHCs are intrinsically active and their firing periodically interrupted by external inhibitory input (IHC-inhibition model), or are intrinsically silent and their firing periodically promoted by an external excitatory stimulus (IHC-excitation model). There is accumulating evidence that inner supporting cells in Kölliker's organ spontaneously release ATP during this time, which can induce bursts of Ca(2+) spikes in IHCs that recapitulate many features of auditory neuron activity observed in vivo. Nevertheless, the role of supporting cells in this process remains to be established in vivo. A greater understanding of the molecular mechanisms responsible for generating IHC activity in the developing cochlea will help reveal how these events contribute to the maturation of nascent auditory circuits. PMID:25296716

  19. Voice activity detection for speaker verification systems

    NASA Astrophysics Data System (ADS)

    Borowski, Filip

    2008-01-01

    Complex algorithm for speech activity detection was presented in this article. It is based on speech enhancement, features extraction and final detection algorithm. The first one was published in ETSI standard as a module of "Advanced front-end feature extraction algorithm" in distributed speech recognition system. It consists of two main parts, noise estimatiom and Wiener filtering. For the final detection modified linear prediction coefficients and spectral entropy features are extracted form denoised signal.

  20. Potentially active copies of the gypsy retroelement are confined to the Y chromosome of some strains of Drosophila melanogaster possibly as the result of the female-specific effect of the flamenco gene.

    PubMed

    Chalvet, F; di Franco, C; Terrinoni, A; Pelisson, A; Junakovic, N; Bucheton, A

    1998-04-01

    Gypsy is an endogenous retrovirus present in the genome of Drosophila melanogaster. This element is mobilized only in the progeny of females which contain active gypsy elements and which are homozygous for permissive alleles of a host gene called flamenco (flam). Some data strongly suggest that gypsy elements bearing a diagnostic HindIII site in the central region of the retrovirus body represent a subfamily that appears to be much more active than elements devoid of this site. We have taken advantage of this structural difference to assess by the Southern blotting technique the genomic distribution of active gypsy elements. In some of the laboratory Drosophila stocks tested, active gypsy elements were found to be restricted to the Y chromosome. Further analyses of 14 strains tested for the permissive vs. restrictive status of their flamenco alleles suggest that the presence of permissive alleles of flam in a stock tends to be associated with the confinement of active gypsy elements to the Y chromosome. This might be the result of the female-specific effect of flamenco on gypsy activity. PMID:9541538

  1. Crystallization, biomimetics and semiconducting polymers in confined systems. (German Title: Kristallisation, Biomimetik und halbleitende Polymere in räumlich begrenzten Systemen)

    NASA Astrophysics Data System (ADS)

    Montenegro, Rivelino V. D.

    2003-05-01

    The colloidal systems are present everywhere in many varieties such as emulsions (liquid droplets dispersed in liquid), aerosols (liquid dispersed in gas), foam (gas in liquid), etc. Among several new methods for the preparation of colloids, the so-called miniemulsion technique has been shown to be one of the most promising. Miniemulsions are defined as stable emulsions consisting of droplets with a size of 50-500 nm by shearing a system containing oil, water, a surfactant, and a highly water insoluble compound, the so-called hydrophobe 1. In the first part of this work, dynamic crystallization and melting experiments are described which were performed in small, stable and narrowly distributed nanodroplets (confined systems) of miniemulsions. Both regular and inverse systems were examined, characterizing, first, the crystallization of hexadecane, secondly, the crystallization of ice. It was shown for both cases that the temperature of crystallization in such droplets is significantly decreased (or the required undercooling is increased) as compared to the bulk material. This was attributed to a very effective suppression of heterogeneous nucleation. It was also found that the required undercooling depends on the nanodroplet size: with decreasing droplet size the undercooling increases. 2. It is shown that the temperature of crystallization of other n-alkanes in nanodroplets is also significantly decreased as compared to the bulk material due to a very effective suppression of heterogeneous nucleation. A very different behavior was detected between odd and even alkanes. In even alkanes, the confinement in small droplets changes the crystal structure from a triclinic (as seen in bulk) to an orthorhombic structure, which is attributed to finite size effects inside the droplets. An intermediate metastable rotator phase is of less relevance for the miniemulsion droplets than in the bulk. For odd alkanes, only a strong temperature shift compared to the bulk system is

  2. Light and immune systems: activation of immunological activities

    NASA Astrophysics Data System (ADS)

    Huang, Zheng; Liu, Hong; Chen, Wei R.

    2006-02-01

    Light has been used to treat diseases for hundreds of years. Convenient and powerful light sources such as lasers make photomedicine a major branch in diseases treatment and detection. Originally, light was often used for local treatment, using photomechanical, photochemical, photothermal reactions and photomodulation as the major mechanisms. More and more investigators have become interested in the systemic effects of light, particularly in its effects on immune systems. Much work has been done to activate and/or enhance the host immune system to combat cancer, either using light as a direct tool or as an adjuvant method. Light has long been used for assisting disease detection and diagnosis. Advances in light technology have made photo-diagnostics ever more precise spatially and temporally. Many techniques facilitate observation of bio-molecule interactions and other biological processes at the cellular level, hence providing opportunities to detect and monitor immune activities. This manuscript will review recent photo-immunological research in treatment of cancer. The recent development of combination therapies involving lasers will be presented. Specifically, the results of cancer treatment using laser photothermal interaction, either with or without additional immunological stimulation will be discussed. The immunological effects of photodynamic therapy (PDT), and of its combination with immunotherapy in cancer treatment will also be discussed. Much interest has been recently concentrated in the immunological responses after laser treatment. Such responses at cellular and molecular levels will be discussed. The effect of these treatment modalities on the distant metastases also showed promise of light induced antitumor immunity. The combination therapy and induced immunological responses appear to be the key for long-term control of tumors.

  3. Active polarimeter optical system laser hazard analysis.

    SciTech Connect

    Augustoni, Arnold L.

    2005-07-01

    A laser hazard analysis was performed for the SNL Active Polarimeter Optical System based on the ANSI Standard Z136.1-2000, American National Standard for Safe Use of Lasers and the ANSI Standard Z136.6-2000, American National Standard for Safe Use of Lasers Outdoors. The Active Polarimeter Optical System (APOS) uses a pulsed, near-infrared, chromium doped lithium strontium aluminum fluoride (Cr:LiSAF) crystal laser in conjunction with a holographic diffuser and lens to illuminate a scene of interest. The APOS is intended for outdoor operations. The system is mounted on a height adjustable platform (6 feet to 40 feet) and sits atop a tripod that points the beam downward. The beam can be pointed from nadir to as much as 60 degrees off of nadir producing an illuminating spot geometry that can vary from circular (at nadir) to elliptical in shape (off of nadir). The JP Innovations crystal Cr:LiSAF laser parameters are presented in section II. The illuminating laser spot size is variable and can be adjusted by adjusting the separation distance between the lens and the holographic diffuser. The system is adjusted while platform is at the lowest level. The laser spot is adjusted for a particular spot size at a particular distance (elevation) from the laser by adjusting the separation distance (d{sub diffuser}) to predetermined values. The downward pointing angle is also adjusted before the platform is raised to the selected operation elevation.

  4. Global Positioning System Synchronized Active Light Autonomous Docking System

    NASA Technical Reports Server (NTRS)

    Howard, Richard T. (Inventor); Book, Michael L. (Inventor); Bryan, Thomas C. (Inventor); Bell, Joseph L. (Inventor)

    1996-01-01

    A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprising at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.

  5. Global Positioning System Synchronized Active Light Autonomous Docking System

    NASA Technical Reports Server (NTRS)

    Howard, Richard (Inventor)

    1994-01-01

    A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprises at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.

  6. Flagella-induced transitions in the collective behavior of confined microswimmers

    NASA Astrophysics Data System (ADS)

    Cheng Hou Tsang, Alan; Kanso, Eva

    2014-08-01

    Bacteria are usually studied in free-swimming planktonic state or in sessile biofilm state. However, little is known about intermediate states where variability in the environmental conditions and/or energy supply to the flagellar propulsive system alter flagellar activity. In this Rapid Communication, we propose an idealized physical model to investigate the effects of flagellar activity on the hydrodynamic interactions among a population of microswimmers. We show that decreasing flagellar activity induces a hydrodynamically triggered transition in confined microswimmers from turbulentlike swimming to aggregation and clustering. These results suggest that the interplay between flagellar activity and hydrodynamic interactions provides a physical mechanism for coordinating collective behaviors in confined bacteria, with potentially profound implications on processes such as molecular diffusion and transport of oxygen and nutrients that mediate transitions in the bacteria physiological state.

  7. Dislocation boundaries and active slip systems

    SciTech Connect

    Wert, J.A.; Hansen, N.

    1995-11-01

    Part of the dislocations which have participated in the plastic deformation of a polycrystalline metal are stored in dislocation boundaries in a two- or three-dimensional arrangement. The dislocation in such boundaries can be analyzed by determining the misorientation between neighboring crystallites and the boundary orientation. Information about the dislocations in the boundaries can also be obtained by an analysis of active slip systems based on the crystallite orientation and the imposed stress or strain state in combination with appropriate constraint conditions. In the present paper an analysis of the boundary dislocation structure and of the slip systems has been conducted for pure aluminium cold-rolled to a von Mises strain of 0.41. The results show that a substantial majority of dislocations in different types of dislocation boundaries are from the primary and conjugate slip system in the adjoining crystallites. A basis is therefore provided for integrating deformation structure observations with plastic deformation behavior.

  8. Extravehicular Activity (EVA) 101: Constellation EVA Systems

    NASA Technical Reports Server (NTRS)

    Jordan, Nicole C.

    2007-01-01

    A viewgraph presentation on Extravehicular Activity (EVA) Systems is shown. The topics include: 1) Why do we need space suits? 2) Protection From the Environment; 3) Primary Life Support System (PLSS); 4) Thermal Control; 5) Communications; 6) Helmet and Extravehicular Visor Assy; 7) Hard Upper Torso (HUT) and Arm Assy; 8) Display and Controls Module (DCM); 9) Gloves; 10) Lower Torso Assembly (LTA); 11) What Size Do You Need?; 12) Boot and Sizing Insert; 13) Boot Heel Clip and Foot Restraint; 14) Advanced and Crew Escape Suit; 15) Nominal & Off-Nominal Landing; 16) Gemini Program (mid-1960s); 17) Apollo EVA on Service Module; 18) A Bold Vision for Space Exploration, Authorized by Congress; 19) EVA System Missions; 20) Configurations; 21) Reduced Gravity Program; and 22) Other Opportunities.

  9. Special issue containing papers presented at the 12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (7-11 September 2011) Special issue containing papers presented at the 12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (7-11 September 2011)

    NASA Astrophysics Data System (ADS)

    Berk, H. L.

    2012-09-01

    The topic of the behaviour of energetic alpha particles in magnetic fusion confined plasmas is perhaps the ultimate frontier plasma physics issue that needs to be understood in the quest to achieve controlled power from the fusion reaction in magnetically confined plasmas. The partial pressure of alpha particles in a burning plasma will be ~5-10% of the total pressure and under these conditions the alpha particles may be prone to develop instability through Alfvénic interaction. This may lead, even with moderate alpha particle loss, to a burn quench or severe wall damage. Alternatively, benign Alfvénic signals may allow the vital information to control a fusion burn. The significance of this issue has led to extensive international investigations and a biannual meeting that began in Kyiv in 1989, followed by subsequent meetings in Aspenäs (1991), Trieste (1993), Princeton (1995), JET/Abingdon (1997), Naka (1999), Gothenburg (2001), San Diego (2003), Takayama (2005), Kloster Seeon (2007) and Kyiv (2009). The meeting was initially entitled 'Alpha Particles in Fusion Research' and then was changed during the 1997 meeting to 'Energetic Particles in Magnetic Confinement Systems' in appreciation of the need to study the significance of the electron runaway, which can lead to the production of energetic electrons with energies that can even exceed the energy produced by fusion products. This special issue presents some of the mature interesting work that was reported at the 12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems, which was held in Austin, Texas, USA (7-11 September 2011). This meeting immediately followed a related meeting, the 5th IAEA Technical Meeting on Theory of Plasma Wave Instabilities (5-7 September 2011). The meetings shared one day (7 September 2011) with presentations relevant to both groups. The presentations from most of the participants, as well as some preliminary versions of papers, are available at the

  10. Somersault of Paramecium in extremely confined environments

    PubMed Central

    Jana, Saikat; Eddins, Aja; Spoon, Corrie; Jung, Sunghwan

    2015-01-01

    We investigate various swimming modes of Paramecium in geometric confinements and a non-swimming self-bending behavior like a somersault, which is quite different from the previously reported behaviors. We observe that Paramecia execute directional sinusoidal trajectories in thick fluid films, whereas Paramecia meander around a localized region and execute frequent turns due to collisions with adjacent walls in thin fluid films. When Paramecia are further constrained in rectangular channels narrower than the length of the cell body, a fraction of meandering Paramecia buckle their body by pushing on the channel walls. The bucking (self-bending) of the cell body allows the Paramecium to reorient its anterior end and explore a completely new direction in extremely confined spaces. Using force deflection method, we quantify the Young’s modulus of the cell and estimate the swimming and bending powers exerted by Paramecium. The analysis shows that Paramecia can utilize a fraction of its swimming power to execute the self-bending maneuver within the confined channel and no extra power may be required for this new kind of self-bending behavior. This investigation sheds light on how micro-organisms can use the flexibility of the body to actively navigate within confined spaces. PMID:26286234

  11. Somersault of Paramecium in extremely confined environments.

    PubMed

    Jana, Saikat; Eddins, Aja; Spoon, Corrie; Jung, Sunghwan

    2015-01-01

    We investigate various swimming modes of Paramecium in geometric confinements and a non-swimming self-bending behavior like a somersault, which is quite different from the previously reported behaviors. We observe that Paramecia execute directional sinusoidal trajectories in thick fluid films, whereas Paramecia meander around a localized region and execute frequent turns due to collisions with adjacent walls in thin fluid films. When Paramecia are further constrained in rectangular channels narrower than the length of the cell body, a fraction of meandering Paramecia buckle their body by pushing on the channel walls. The bucking (self-bending) of the cell body allows the Paramecium to reorient its anterior end and explore a completely new direction in extremely confined spaces. Using force deflection method, we quantify the Young's modulus of the cell and estimate the swimming and bending powers exerted by Paramecium. The analysis shows that Paramecia can utilize a fraction of its swimming power to execute the self-bending maneuver within the confined channel and no extra power may be required for this new kind of self-bending behavior. This investigation sheds light on how micro-organisms can use the flexibility of the body to actively navigate within confined spaces. PMID:26286234

  12. Somersault of Paramecium in extremely confined environments

    NASA Astrophysics Data System (ADS)

    Jana, Saikat; Eddins, Aja; Spoon, Corrie; Jung, Sunghwan

    2015-08-01

    We investigate various swimming modes of Paramecium in geometric confinements and a non-swimming self-bending behavior like a somersault, which is quite different from the previously reported behaviors. We observe that Paramecia execute directional sinusoidal trajectories in thick fluid films, whereas Paramecia meander around a localized region and execute frequent turns due to collisions with adjacent walls in thin fluid films. When Paramecia are further constrained in rectangular channels narrower than the length of the cell body, a fraction of meandering Paramecia buckle their body by pushing on the channel walls. The bucking (self-bending) of the cell body allows the Paramecium to reorient its anterior end and explore a completely new direction in extremely confined spaces. Using force deflection method, we quantify the Young’s modulus of the cell and estimate the swimming and bending powers exerted by Paramecium. The analysis shows that Paramecia can utilize a fraction of its swimming power to execute the self-bending maneuver within the confined channel and no extra power may be required for this new kind of self-bending behavior. This investigation sheds light on how micro-organisms can use the flexibility of the body to actively navigate within confined spaces.

  13. De-confinement in small systems: Clustering of color sources in high multiplicity p¯p collisions at s = 1.8TeV

    NASA Astrophysics Data System (ADS)

    Gutay, L. J.; Hirsch, A. S.; Scharenberg, R. P.; Srivastava, B. K.; Pajares, C.

    2015-12-01

    It is shown that de-confinement can be achieved in high multiplicity nonjet p¯p collisions at s = 1.8TeV Fermi National Accelerator Laboratory (FNAL- E735) experiment. Previously, the evidence for de-confinement was demonstrated by the constant freeze out energy density in high multiplicity events. In this paper, we use the same but analyze the transverse momentum spectrum in the framework of the clustering of color sources. This frame work naturally predicts the reduction in the charged particle multiplicity with respect to the value expected from the number of independent strings. The charged particle pseudorapidity densities in the range 7.0 ≤≤ 26.0 are considered. Results are presented for both thermodynamic and transport properties. The initial temperature and energy density are obtained from the data via the color reduction factor F(ξ) and the associated string density parameter ξ. The Bjorken ideal fluid description of the QGP, when modified by the color reduction factor and the trace anomaly Δ is in remarkable agreement with the lattice quantum chromo dynamics (LQCD) simulations. The energy density (ɛ/T4) ˜ 11.5 for ˜ 25.0 is close to the value for 0-10% central events in Au+Au collisions at sNN = 200GeV. The shear viscosity to entropy density ratio (η/s) is ˜0.2 at the transition temperature of 167MeV. The result for the trace anomaly Δ is in excellent agreement with LQCD simulations. These results confirm our earlier observation that the de-confined state of matter was created in high multiplicity events in p¯p collisions at s = 1.8TeV.

  14. The synchronous active neutron detection assay system

    SciTech Connect

    Pickrell, M.M.; Kendall, P.K.

    1994-08-01

    We have begun to develop a novel technique for active neutron assay of fissile material in spent nuclear fuel. This approach will exploit a 14-MeV neutron generator developed by Schlumberger. The technique, termed synchronous active neutron detection (SAND), follows a method used routinely in other branches of physics to detect very small signals in presence of large backgrounds. Synchronous detection instruments are widely available commercially and are termed ``lock-in`` amplifiers. We have implemented a digital lock-in amplifier in conjunction with the Schlumberger neutron generator to explore the possibility of synchronous detection with active neutrons. The Schlumberger system can operate at up to a 50% duty factor, in effect, a square wave of neutron yield. Results are preliminary but promising. The system is capable of resolving the fissile material contained in a small fraction of the fuel rods in a cold fuel assembly; it also appears resilient to background neutron interference. The interrogating neutrons appear to be non-thermal and penetrating. Work remains to fully explore relevant physics and optimize instrument design.

  15. Active Thermal Control System Development for Exploration

    NASA Technical Reports Server (NTRS)

    Westheimer, David

    2007-01-01

    All space vehicles or habitats require thermal management to maintain a safe and operational environment for both crew and hardware. Active Thermal Control Systems (ATCS) perform the functions of acquiring heat from both crew and hardware within a vehicle, transporting that heat throughout the vehicle, and finally rejecting that energy into space. Almost all of the energy used in a space vehicle eventually turns into heat, which must be rejected in order to maintain an energy balance and temperature control of the vehicle. For crewed vehicles, Active Thermal Control Systems are pumped fluid loops that are made up of components designed to perform these functions. NASA has been actively developing technologies that will enable future missions or will provide significant improvements over the state of the art technologies. These technologies have are targeted for application on the Crew Exploration Vehicle (CEV), or Orion, and a Lunar Surface Access Module (LSAM). The technologies that have been selected and are currently under development include: fluids that enable single loop ATCS architectures, a gravity insensitive vapor compression cycle heat pump, a sublimator with reduced sensitivity to feedwater contamination, an evaporative heat sink that can operate in multiple ambient pressure environments, a compact spray evaporator, and lightweight radiators that take advantage of carbon composites and advanced optical coatings.

  16. Method and system to directly produce electrical power within the lithium blanket region of a magnetically confined, deuterium-tritium (DT) fueled, thermonuclear fusion reactor

    DOEpatents

    Woolley, Robert D.

    1999-01-01

    A method for integrating liquid metal magnetohydrodynamic power generation with fusion blanket technology to produce electrical power from a thermonuclear fusion reactor located within a confining magnetic field and within a toroidal structure. A hot liquid metal flows from a liquid metal blanket region into a pump duct of an electromagnetic pump which moves the liquid metal to a mixer where a gas of predetermined pressure is mixed with the pressurized liquid metal to form a Froth mixture. Electrical power is generated by flowing the Froth mixture between electrodes in a generator duct. When the Froth mixture exits the generator the gas is separated from the liquid metal and both are recycled.

  17. Method and System to Directly Produce Electrical Power within the Lithium Blanket Region of a Magnetically Confined, Deuterium-Tritium (DT) Fueled, Thermonuclear Fusion Reactor

    SciTech Connect

    Woolley, Robert D.

    1998-09-22

    A method for integrating liquid metal magnetohydrodynamic power generation with fusion blanket technology to produce electrical power from a thermonuclear fusion reactor located within a confining magnetic field and within a toroidal structure. A hot liquid metal flows from a liquid metal blanket region into a pump duct of an electromagnetic pump which moves the liquid metal to a mixer where a gas of predetermined pressure is mixed with the pressurized liquid metal to form a Froth mixture. Electrical power is generated by flowing the Froth mixture between electrodes in a generator duct. When the Froth mixture exits the generator the gas is separated from the liquid metal and both are recycled.

  18. Inertial confinement fusion

    SciTech Connect

    Powers, L.; Condouris, R.; Kotowski, M.; Murphy, P.W.

    1992-01-01

    This issue of the ICF Quarterly contains seven articles that describe recent progress in Lawrence Livermore National Laboratory's ICF program. The Department of Energy recently initiated an effort to design a 1--2 MJ glass laser, the proposed National Ignition Facility (NIF). These articles span various aspects of a program which is aimed at moving forward toward such a facility by continuing to use the Nova laser to gain understanding of NIF-relevant target physics, by developing concepts for an NIF laser driver, and by envisioning a variety of applications for larger ICF facilities. This report discusses research on the following topics: Stimulated Rotational Raman Scattering in Nitrogen; A Maxwell Equation Solver in LASNEX for the Simulation of Moderately Intense Ultrashort Pulse Experiments; Measurements of Radial Heat-Wave Propagation in Laser-Produced Plasmas; Laser-Seeded Modulation Growth on Directly Driven Foils; Stimulated Raman Scattering in Large-Aperture, High-Fluence Frequency-Conversion Crystals; Fission Product Hazard Reduction Using Inertial Fusion Energy; Use of Inertial Confinement Fusion for Nuclear Weapons Effects Simulations.

  19. Advanced Active Thermal Control Systems Architecture Study

    NASA Technical Reports Server (NTRS)

    Hanford, Anthony J.; Ewert, Michael K.

    1996-01-01

    The Johnson Space Center (JSC) initiated a dynamic study to determine possible improvements available through advanced technologies (not used on previous or current human vehicles), identify promising development initiatives for advanced active thermal control systems (ATCS's), and help prioritize funding and personnel distribution among many research projects by providing a common basis to compare several diverse technologies. Some technologies included were two-phase thermal control systems, light-weight radiators, phase-change thermal storage, rotary fluid coupler, and heat pumps. JSC designed the study to estimate potential benefits from these various proposed and under-development thermal control technologies for five possible human missions early in the next century. The study compared all the technologies to a baseline mission using mass as a basis. Each baseline mission assumed an internal thermal control system; an external thermal control system; and aluminum, flow-through radiators. Solar vapor compression heat pumps and light-weight radiators showed the greatest promise as general advanced thermal technologies which can be applied across a range of missions. This initial study identified several other promising ATCS technologies which offer mass savings and other savings compared to traditional thermal control systems. Because the study format compares various architectures with a commonly defined baseline, it is versatile and expandable, and is expected to be updated as needed.

  20. Noninvasive ambulatory measurement system of cardiac activity.

    PubMed

    Pino, Esteban J; Chavez, Javier A P; Aqueveque, Pablo

    2015-08-01

    This work implements a noninvasive system that measures the movements caused by cardiac activity. It uses unobtrusive Electro-Mechanical Films (EMFi) on the seat and on the backrest of a regular chair. The system detects ballistocardiogram (BCG) and respiration movements. Real data was obtained from 54 volunteers. 19 of them were measured in the laboratory and 35 in a hospital waiting room. Using a BIOPAC acquisition system, the ECG was measured simultaneously to the BCG for comparison. Wavelet Transform (WT) is a better option than Empirical Mode Decomposition (EMD) for signal extraction and produces higher effective measurement time. In the laboratory, the best results are obtained on the seat. The correlation index was 0.9800 and the Bland-Altman limits of agreement were 0.7136 ± 4.3673 [BPM]. In the hospital waiting room, the best results are also from the seat sensor. The correlation index was 0.9840, and the limits of agreement were 0.4386 ± 3.5884 [BPM]. The system is able to measure BCG in an unobtrusive way and determine the cardiac frequency with high precision. It is simple to use, which means the system can easily be used in non-standard settings: resting in a chair or couch, at the gym, schools or in a hospital waiting room, as shown. PMID:26738057

  1. Velocity distribution in active particles systems

    PubMed Central

    Marconi, Umberto Marini Bettolo; Gnan, Nicoletta; Paoluzzi, Matteo; Maggi, Claudio; Di Leonardo, Roberto

    2016-01-01

    We derive an analytic expression for the distribution of velocities of multiple interacting active particles which we test by numerical simulations. In clear contrast with equilibrium we find that the velocities are coupled to positions. Our model shows that, even for two particles only, the individual velocities display a variance depending on the interparticle separation and the emergence of correlations between the velocities of the particles. When considering systems composed of many particles we find an analytic expression connecting the overall velocity variance to density, at the mean-field level, and to the pair distribution function valid in the limit of small noise correlation times. Finally we discuss the intriguing analogies and main differences between our effective free energy functional and the theoretical scenario proposed so far for phase-separating active particles. PMID:27001289

  2. Velocity distribution in active particles systems

    NASA Astrophysics Data System (ADS)

    Marconi, Umberto Marini Bettolo; Gnan, Nicoletta; Paoluzzi, Matteo; Maggi, Claudio; di Leonardo, Roberto

    2016-03-01

    We derive an analytic expression for the distribution of velocities of multiple interacting active particles which we test by numerical simulations. In clear contrast with equilibrium we find that the velocities are coupled to positions. Our model shows that, even for two particles only, the individual velocities display a variance depending on the interparticle separation and the emergence of correlations between the velocities of the particles. When considering systems composed of many particles we find an analytic expression connecting the overall velocity variance to density, at the mean-field level, and to the pair distribution function valid in the limit of small noise correlation times. Finally we discuss the intriguing analogies and main differences between our effective free energy functional and the theoretical scenario proposed so far for phase-separating active particles.

  3. Nonlinear adhesion dynamics of confined lipid membranes

    NASA Astrophysics Data System (ADS)

    To, Tung; Le Goff, Thomas; Pierre-Louis, Olivier

    Lipid membranes, which are ubiquitous objects in biological environments are often confined. For example, they can be sandwiched between a substrate and the cytoskeleton between cell adhesion, or between other membranes in stacks, or in the Golgi apparatus. We present a study of the nonlinear dynamics of membranes in a model system, where the membrane is confined between two flat walls. The dynamics derived from the lubrication approximation is highly nonlinear and nonlocal. The solution of this model in one dimension exhibits frozen states due to oscillatory interactions between membranes caused by the bending rigidity. We develope a kink model for these phenomena based on the historical work of Kawasaki and Otha. In two dimensions, the dynamics is more complex, and depends strongly on the amount of excess area in the system. We discuss the relevance of our findings for experiments on model membranes, and for biological systems. Supported by the grand ANR Biolub.

  4. Morphology of diblock copolymers under confinement

    NASA Astrophysics Data System (ADS)

    Ackerman, David; Ganapathysubramanian, Baskar

    The structure adopted by polymer chains is of particular intrest for materials design. In particular, a great deal of effort has been made to study diblock polymers due to the importance they have in industrial applications. The bulk structure of most systems has been the most widely studied. However, when under the effect of confinement, the polymer chains are forced to adopt structures differing from the familiar bulk phases. As many applications utilize polymers in sizes and shapes that lead to these non bulk structures, the confinement effects are important. A commonly used tool for computationally determining structures is the continuum self consistant field theory (SCFT). We discuss our highly scalable parallel framework for SCFT using real space methods (finite element) that is especially well suited to modelling complex geometries. This framework is capable of modeling both Gaussian and worm like chains. We illustate the use of the software framework in determining structures under varying degrees of confinement. We detail the method used and present selected results from a systematic study of confinement using arbitrary structures.

  5. A Group Recommender System for Tourist Activities

    NASA Astrophysics Data System (ADS)

    Garcia, Inma; Sebastia, Laura; Onaindia, Eva; Guzman, Cesar

    This paper introduces a method for giving recommendations of tourist activities to a group of users. This method makes recommendations based on the group tastes, their demographic classification and the places visited by the users in former trips. The group recommendation is computed from individual personal recommendations through the use of techniques such as aggregation, intersection or incremental intersection. This method is implemented as an extension of the e-Tourism tool, which is a user-adapted tourism and leisure application, whose main component is the Generalist Recommender System Kernel (GRSK), a domain-independent taxonomy-driven search engine that manages the group recommendation.

  6. Influenza virus activation of the interferon system

    PubMed Central

    Killip, Marian J.; Fodor, Ervin; Randall, Richard E.

    2015-01-01

    The host interferon (IFN) response represents one of the first barriers that influenza viruses must surmount in order to establish an infection. Many advances have been made in recent years in understanding the interactions between influenza viruses and the interferon system. In this review, we summarise recent work regarding activation of the type I IFN response by influenza viruses, including attempts to identify the viral RNA responsible for IFN induction, the stage of the virus life cycle at which it is generated and the role of defective viruses in this process. PMID:25678267

  7. System and method for monitoring cellular activity

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H. (Inventor); Fraser, Scott E. (Inventor); Lansford, Russell D. (Inventor)

    2002-01-01

    A system and method for monitoring cellular activity in a cellular specimen. According to one embodiment, a plurality of excitable markers are applied to the specimen. A multi-photon laser microscope is provided to excite a region of the specimen and cause fluorescence to be radiated from the region. The radiating fluorescence is processed by a spectral analyzer to separate the fluorescence into respective wavelength bands. The respective bands of fluorescence are then collected by an array of detectors, with each detector receiving a corresponding one of the wavelength bands.

  8. LDEF active optical system components experiment

    NASA Technical Reports Server (NTRS)

    Blue, M. D.

    1991-01-01

    A preliminary report on the Active Optical System Components Experiment is presented. This experiment contained 136 components in a six-inch deep tray including lasers, infrared detectors and arrays, ultraviolet light detectors, light-emitting diodes, a light modulator, flash lamps, optical filters, glasses, and samples of surface finishes. The experimental results for those component characteristics appear as much related to the passage of time as to the effects of the space environment, but organic materials and extreme-infrared reflectivity of black paints show unexpected changes.

  9. LDEF active optical system components experiment

    NASA Technical Reports Server (NTRS)

    Blue, M. D.

    1992-01-01

    A preliminary report on the Active Optical System Components Experiment is presented. This experiment contained 136 components in a six inch deep tray including lasers, infrared detectors and arrays, ultraviolet light detectors, light-emitting diodes, a light modulator, flash lamps, optical filters, glasses, and samples of surface finishes. Thermal, mechanical, and structural considerations leading to the design of the tray hardware are discussed. In general, changes in the retested component characteristics appear as much related to the passage of time as to the effects of the space environment, but organic materials, multilayer optical interference filters, and extreme-infrared reflectivity of black paints show unexpected changes.

  10. System and method for monitoring cellular activity

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H. (Inventor); Fraser, Scott E. (Inventor); Lansford, Russell D. (Inventor)

    2004-01-01

    A system and method for monitoring cellular activity in a cellular specimen. According to one embodiment, a plurality of excitable markers are applied to the specimen. A multi-photon laser microscope is provided to excite a region of the specimen and cause fluorescence to be radiated from the region. The radiating fluorescence is processed by a spectral analyzer to separate the fluorescence into respective wavelength bands. The respective bands of fluorescence are then collected by an array of detectors, with each detector receiving a corresponding one of the wavelength bands.

  11. De-Confinement in small systems: Clustering of color sources in high multiplicity p¯p collisions at √s = 1.8 TeV

    NASA Astrophysics Data System (ADS)

    Gutay, L. J.

    2016-07-01

    It is shown that de-confinement can be achieved in high multiplicity non jet p¯p collisions at √s = 1.8 TeV Fermi National Accelerator Laboratory(FNAL- E735) experiment. In this paper we have analyzed the transverse momentum spectrum in the framework of the clustering of color sources. This frame-work naturally predicts the reduction in the charged particle multiplicity with respect to the value expected from the number of independent strings. Results are presented for both thermodynamic and transport properties. The initial temperature and energy density are obtained from the data via the color reduction factor F(ξ) and the associated string density parameter ξ. The results for he trace anomaly Δ and shear viscosity to entropy density ratio(η/s) are presented. These results confirm our earlier observation that the de-confined state of matter was created in high multiplicity events in p¯p collisions at √s = 1.8 TeV.

  12. Analog VLSI system for active drag reduction

    SciTech Connect

    Gupta, B.; Goodman, R.; Jiang, F.; Tai, Y.C.; Tung, S.; Ho, C.M.

    1996-10-01

    In today`s cost-conscious air transportation industry, fuel costs are a substantial economic concern. Drag reduction is an important way to reduce costs. Even a 5% reduction in drag translates into estimated savings of millions of dollars in fuel costs. Drawing inspiration from the structure of shark skin, the authors are building a system to reduce drag along a surface. Our analog VLSI system interfaces with microfabricated, constant-temperature shear stress sensors. It detects regions of high shear stress and outputs a control signal to activate a microactuator. We are in the process of verifying the actual drag reduction by controlling microactuators in wind tunnel experiments. We are encouraged that an approach similar to one that biology employs provides a very useful contribution to the problem of drag reduction. 9 refs., 21 figs.

  13. Spontaneous Oscillations in an Active Matter System

    NASA Astrophysics Data System (ADS)

    Hayes, Robert; Tsang, Boyce; Granick, Steve

    Active matter (which consumes energy to move about) can organize into dynamic structures more interesting than those possible at steady-state. Here we show spontaneous periodic self-assembly in a simple three-component system of water, oil phase, and surfactant at constant room temperature, with emphasis on one model system. Benchtop experiments show that liquid crystal oil droplets spontaneously and collectively oscillate like a `beating heart' for several hours; contract, relax, and subsequently re-contract in a petri dish at a rate of a few `beats' per minute. These oscillations, emergent from the cooperative interaction of the three components, are driven by the competition between positive and negative feedback processes. This illustration of feedback in action reveals a new way to program self-assembled structures to vary with time.

  14. Actively controlled vibration welding system and method

    SciTech Connect

    Cai, Wayne W.; Kang, Bongsu; Tan, Chin-An

    2013-04-02

    A vibration welding system includes a controller, welding horn, an active material element, and anvil assembly. The assembly may include an anvil body connected to a back plate and support member. The element, e.g., a piezoelectric stack or shape memory alloy, is positioned with respect to the assembly. The horn vibrates in a desirable first direction to form a weld on a work piece. The element controls any vibrations in a second direction by applying calibrated response to the anvil body in the second direction. A method for controlling undesirable vibrations in the system includes positioning the element with respect to the anvil assembly, connecting the anvil body to the support member through the back plate, vibrating the horn in a desirable first direction, and transmitting an input signal to the element to control vibration in an undesirable second direction.

  15. Active alignment/contact verification system

    DOEpatents

    Greenbaum, William M.

    2000-01-01

    A system involving an active (i.e. electrical) technique for the verification of: 1) close tolerance mechanical alignment between two component, and 2) electrical contact between mating through an elastomeric interface. For example, the two components may be an alumina carrier and a printed circuit board, two mating parts that are extremely small, high density parts and require alignment within a fraction of a mil, as well as a specified interface point of engagement between the parts. The system comprises pairs of conductive structures defined in the surfaces layers of the alumina carrier and the printed circuit board, for example. The first pair of conductive structures relate to item (1) above and permit alignment verification between mating parts. The second pair of conductive structures relate to item (2) above and permit verification of electrical contact between mating parts.

  16. Active balance system and vibration balanced machine

    NASA Technical Reports Server (NTRS)

    Qiu, Songgang (Inventor); Augenblick, John E. (Inventor); Peterson, Allen A. (Inventor); White, Maurice A. (Inventor)

    2005-01-01

    An active balance system is provided for counterbalancing vibrations of an axially reciprocating machine. The balance system includes a support member, a flexure assembly, a counterbalance mass, and a linear motor or an actuator. The support member is configured for attachment to the machine. The flexure assembly includes at least one flat spring having connections along a central portion and an outer peripheral portion. One of the central portion and the outer peripheral portion is fixedly mounted to the support member. The counterbalance mass is fixedly carried by the flexure assembly along another of the central portion and the outer peripheral portion. The linear motor has one of a stator and a mover fixedly mounted to the support member and another of the stator and the mover fixedly mounted to the counterbalance mass. The linear motor is operative to axially reciprocate the counterbalance mass.

  17. Polarized Water Wires under Confinement in Chiral Channels.

    PubMed

    Barboiu, Mihail; Cazade, Pierre-André; Le Duc, Yann; Legrand, Yves-Marie; van der Lee, Arie; Coasne, Benoit

    2015-07-16

    The alignment of water molecules along chiral pores may activate proton/ion conduction along dipolar hydrophilic pathways. Here we show that a simple synthetic "T-channel" forms a directional pore with its carbonyl moieties solvated by chiral helical water wires. Atom-scale simulations and experimental crystallographic assays reveal a dynamical structure of water and electrolyte solutions (alkali metal chlorides) confined in these organic T-channels. Oscillations in the dipole orientation, which correspond to alternative ordering (dipole up-dipole down) of the water molecules with a period of about 4.2 Å (imposed by the distance between two successive carbonyl groups) are observed. When ions are added to the system, despite the strong Coulombic water/ion interaction, confined water remains significantly ordered in the T-channel and still exhibits surface-induced polarization. Cation permeation can be achieved through alternated hydration-dehydration occurring along strongly oriented water wires. The T-channel, which exhibits chirality with strong water orientation, provides an opportunity to unravel novel water-channel systems that share many interesting properties of biomolecular systems. PMID:26090910

  18. Accelerated dynamics of supercooled glycerol in soft confinement

    NASA Astrophysics Data System (ADS)

    Blochowicz, T.; Gouirand, E.; Fricke, A.; Spehr, T.; Stühn, B.; Frick, B.

    2009-06-01

    We investigate the dynamics of supercooled glycerol in a soft confinement within microemulsion droplets. The structure of the system is characterized by small-angle neutron scattering. We show that temperature-stable droplets establish a confinement, which may be varied in size from about 1 to 10 nm. Subsequently we focus on the dynamics of glass-forming glycerol confined within nanodroplets of different sizes. By combining neutron backscattering and time-of-flight for a broad dynamic range we obtain the incoherent intermediate scattering function S(q,t), which reveals increasingly accelerated dynamics as glycerol is confined to smaller droplets and for the relaxation times a crossover from Vogel-Fulcher behavior in the bulk to an Arrhenius law in confinement.

  19. Confinement & Stability in MAST

    NASA Astrophysics Data System (ADS)

    Akers, Rob

    2001-10-01

    Transition to H-mode has been achieved in the MAST spherical tokamak (ST) for both ohmically and neutral beam heated plasmas (P_NBI ~ 0.5-1.5MW), resulting in double-null diverted discharges containing both regular and irregular edge localised modes (ELMs). The observed L-H power threshold is ~10 times higher than predicted by established empirical scalings. L-H transition in MAST is accompanied by a sharp increase in edge density gradient, the efficient conversion of internal electron Bernstein waves into free space waves, the onset and saturation of edge poloidal rotation and a marked decrease in turbulence. During ELM free periods, a reduction in outboard power deposition width is observed using a Langmuir probe array. A novel divertor structure has been installed to counter the resulting increase in target heat-flux by applying a toroidally varying potential to the divertor plasma, theory suggesting that convective broadening of the scrape off layer will take place. Global confinement in H-mode is found to routinely exceed the international IPB(y,2) scaling, even for discharges approaching the Greenwald density. In an attempt to further extend the density range (densities in excess of Greenwald having been achieved for plasma currents up to 0.8MA) a multi-pellet injector has been installed at the low-field-side. In addition, high field side fuelling can be supplied via a gas-feed located at the centre-column mid-plane, this technique having been found to significantly enhance H-mode accessibility and quality. A range of stability issues will be discussed, including vertical displacement events, the rich variety of high frequency MHD seen in MAST and the physics of the Neoclassical Tearing Mode. This work was funded by the UK Department of Trade and Industry and by EURATOM. The NBI equipment is on loan from ORNL and the pellet injector was provided by FOM.

  20. Dissipation-Driven Behavior of Nonpropagating Hydrodynamic Solitons Under Confinement

    NASA Astrophysics Data System (ADS)

    Gordillo, Leonardo; García-Áustes, Mónica A.

    2014-04-01

    We have identified a physical mechanism that rules the confinement of nonpropagating hydrodynamic solitons. We show that thin boundary layers arising on walls are responsible for a jump in the local damping. The outcome is a weak dissipation-driven repulsion that determines decisively the solitons' long-time behavior. Numerical simulations of our model are consistent with experiments. Our results uncover how confinement can generate a localized distribution of dissipation in out-of-equilibrium systems. Moreover, they show the preponderance of such a subtle effect in the behavior of localized structures. The reported results should explain the dynamic behavior of other confined dissipative systems.

  1. Psychopathological effects of solitary confinement.

    PubMed

    Grassian, S

    1983-11-01

    Psychopathological reactions to solitary confinement were extensively described by nineteenth-century German clinicians. In the United States there have been several legal challenges to the use of solitary confinement, based on allegations that it may have serious psychiatric consequences. The recent medical literature on this subject has been scarce. The author describes psychiatric symptoms that appeared in 14 inmates exposed to periods of increased social isolation and sensory restriction in solitary confinement and asserts that these symptoms form a major, clinically distinguishable psychiatric syndrome. PMID:6624990

  2. ITER EDA design confinement capability

    NASA Astrophysics Data System (ADS)

    Uckan, N. A.

    Major device parameters for ITER-EDA and CDA are given in this paper. Ignition capability of the EDA (and CDA) operational scenarios is evaluated using both the 1 1/2-D time-dependent transport simulations and 0-D global models under different confinement ((chi((gradient)(T)(sub e)(sub crit)), empirical global energy confinement scalings, chi(empirical), etc.) assumptions. Results from some of these transport simulations and confinement assessments are summarized in and compared with the ITER CDA results.

  3. Next Generation Active Buffet Suppression System

    NASA Technical Reports Server (NTRS)

    Galea, Stephen C.; Ryall, Thomas G.; Henderson, Douglas A.; Moses, Robert W.; White, Edward V.; Zimcik, David G.

    2003-01-01

    Buffeting is an aeroelastic phenomenon that is common to high performance aircraft, especially those with twin vertical tails like the F/A-18, at high angles of attack. These loads result in significant random stresses, which may cause fatigue damage leading to restricted capabilities and availability of the aircraft. This paper describes an international collaborative research activity among Australia, Canada and the United States involving the use of active structural control to alleviate the damaging structural response to these loads. The research program is being co-ordinated by the Air Force Research Laboratory (AFRL) and is being conducted under the auspices of The Technical Cooperative Program (TTCP). This truly unique collaborative program has been developed to enable each participating country to contribute resources toward a program that coalesces a broad range of technical knowledge and expertise into a single investigation. This collaborative program is directed toward a full-scale test of an F/A-18 empennage, which is an extension of an earlier initial test. The current program aims at applying advanced directional piezoactuators, the aircraft rudder, switch mode amplifiers and advanced control strategies on a full-scale structure to demonstrate the enhanced performance and capability of the advanced active BLA control system in preparation for a flight test demonstration.

  4. The synchronous active neutron detection assay system

    SciTech Connect

    Pickrell, M.M.; Kendall, P.K.

    1994-09-01

    The authors have begun to develop a novel technique for active neutron assay of fissile material in spent nuclear fuel. They are using a Schlumberger neutron generator for the direct measurement of the fissile material content in spent fuel, in place of the indirect measures used at present. The technique they are investigating is termed synchronous active neutron detection (SAND). It closely follows a method that has been used routinely in other branches of physics for the detection of very small signals in the presence of large backgrounds. Synchronous detection instruments are widely available commercially and are termed ``lock-in`` amplifiers. They have implemented a digital lock-in amplifier in conjunction with the Schlumberger neutron generator to explore the possibility of synchronous detection with active neutrons. The results to data are preliminary but quite promising. The system is capable of resolving the fissile material contained in a small fraction of the fuel rods in a cold fuel assembly. It also appears to be quite resilient to background neutron interference.

  5. Study of the Three-dimensional Coronal Magnetic Field of Active Region 11117 around the Time of a Confined Flare Using a Data-Driven CESE-MHD Model

    NASA Astrophysics Data System (ADS)

    Jiang, Chaowei; Feng, Xueshang; Wu, S. T.; Hu, Qiang

    2012-11-01

    We apply a data-driven magnetohydrodynamics (MHD) model to investigate the three-dimensional (3D) magnetic field of NOAA active region (AR) 11117 around the time of a C-class confined flare that occurred on 2010 October 25. The MHD model, based on the spacetime conservation-element and solution-element scheme, is designed to focus on the magnetic field evolution and to consider a simplified solar atomsphere with finite plasma β. Magnetic vector-field data derived from the observations at the photosphere is inputted directly to constrain the model. Assuming that the dynamic evolution of the coronal magnetic field can be approximated by successive equilibria, we solve a time sequence of MHD equilibria based on a set of vector magnetograms for AR 11117 taken by the Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory around the time of the flare. The model qualitatively reproduces the basic structures of the 3D magnetic field, as supported by the visual similarity between the field lines and the coronal loops observed by the Atmospheric Imaging Assembly, which shows that the coronal field can indeed be well characterized by the MHD equilibrium in most cases. The magnetic configuration changes very little during the studied time interval of 2 hr. A topological analysis reveals that the small flare is correlated with a bald patch (BP, where the magnetic field is tangent to the photosphere), suggesting that the energy release of the flare can be understood by magnetic reconnection associated with the BP separatrices. The total magnetic flux and energy keep increasing slightly in spite of the flare, while the computed magnetic free energy drops during the flare by ~1030 erg, which seems to be adequate in providing the energy budget of a minor C-class confined flare.

  6. Systemic lupus erythematosus activity. An operational definition.

    PubMed

    Liang, M H; Stern, S; Esdaile, J M

    1988-04-01

    Improved diagnosis and treatment have reduced mortality from SLE and present us with an opportunity to consider SLE in finer distinctions than alive or dead. Although much has been learned about SLE without a gold standard of disease activity or a universally agreed-upon definition of SLE activity, standardization of one or more measures would greatly enhance our ability to compare results from different centers and to communicate more precisely. It is unlikely that any of the existing measures or any ones to be developed will completely satisfy everyone's needs but it is pointless to proliferate new ones without testing their metric properties. Some differences in concept are desirable, particularly for investigators who have specialized interests or insights, but each should meet criteria of reliability and validity and have explicit definitions of terms, rules for their ascertainment, and the time period covered. Moreover, agreement on minimum essential elements of any SLE activity measure and their operational definitions would be a boon. SLE activity is one dimension in the disease pathway of lupus and implies a continuous phenomena that is potentially reversible. Organ damage, another point in the path of causation, connotes irreversible disease. We recommend that minimum essential elements be based on their frequency of occurrence, biological sensibleness, and the likelihood that degrees of activity can be rated reliably to show a change in a clinical state. The rating should be independent of whether a therapy is employed. Since activity is always considered with severity, the two dimensions could be recognized in the scale. Severity can be used to expand a scale's gradations if a symptom or sign is present. Severity could be rated by the need to treat with immunosuppressive agents, the need to follow the patient more closely, or the functional or prognostic consequences of the manifestation. For every organ system clinical judgment should be used to decide

  7. Effects of geometrical confinement in membrane pores on enzyme-based layer-by-layer assemblies

    NASA Astrophysics Data System (ADS)

    Ramírez-Wong, Diana G.; Coelho-Diogo, Cristina; Aimé, Carole; Bonhomme, Christian; Jonas, Alain M.; Demoustier-Champagne, Sophie

    2015-05-01

    Micro- and nanoporous systems incorporating bioactive molecules, such as enzymes, are very promising supports for biocatalysis. Here, we investigate the influence of geometrical confinement on the layer-by-layer (LbL) assembly of enzyme-based thin films, using the polyionic couple (chitosan/β-lactamase)n. Thin films with different number of layers were prepared on flat silicon wafers and within cylindrical submicron pores of polycarbonate membranes to determine the impact of the confinement of macromolecules on: (i) the LbL film growth, (ii) the enzyme loading, and (iii) the biocatalytic efficiency. Solid-state NMR is employed to estimate the amount of enzyme loaded in the different types of LbL films, and the enzyme activity is determined by the study of the kinetics of nitrocefin hydrolysis. Film growth and loading of enzyme occur faster in the confined medium, until pores reach saturation. Moreover, when LbL films are grown within nanopores, the weight fraction of enzyme is very high and remains constant along the build-up. Conversely, the relative amount of enzyme in flat films significantly decreases with the number of layers due to the partial exchange during the growth. Finally, our study emphasizes that the immobilization of enzymes through LbL assembly in confined media can lead to very active surfaces with a restricted number of LbL cycles.

  8. A new melanoma diagnosis active support system.

    PubMed

    Fiorini, R A; Dacquino, G; Laguteta, G

    2004-01-01

    The aim of this paper is to present the operational performance of a new MDASS (Melanoma Diagnosis Active Support System) prototype able to distil optimal knowledge from acquired data to automatically capture and reliably discriminate and quantify the stage of disease evolution. Automated classification dermatoscopical parameters can be divided into two main classes: Size Descriptor (point size, local, and global) and Intrinsic Descriptor (morphological, geometrical, chromatic, others). Usually elementary geometric shape robust and effective characterization, invariant to environment and optical geometry transformations, on a rigorous mathematical level is a key and computational intensive problem. MDASS uses GEOGINE (GEOmetrical enGINE), a state-of-the-art OMG (Ontological Model Generator) based on n-D Tensor Moment Invariants for shape/texture effective description. MDASS main results show robust disease classification procedure with distillation of minimal reference grids for pathological cases and they ultimately achieve effective early diagnosis of melanocytic lesion. System results are validated by carefully designed experiments with certified clinical reference database. Overall system operational performance is presented. Finally, MDASS error analysis and computational complexity are addressed and discussed. PMID:17270962

  9. Alternative approaches to plasma confinement

    NASA Technical Reports Server (NTRS)

    Roth, J. R.

    1978-01-01

    The paper discusses 20 plasma confinement schemes each representing an alternative to the tokamak fusion reactor. Attention is given to: (1) tokamak-like devices (TORMAC, Topolotron, and the Extrap concept), (2) stellarator-like devices (Torsatron and twisted-coil stellarators), (3) mirror machines (Astron and reversed-field devices, the 2XII B experiment, laser-heated solenoids, the LITE experiment, the Kaktus-Surmac concept), (4) bumpy tori (hot electron bumpy torus, toroidal minimum-B configurations), (5) electrostatically assisted confinement (electrostatically stuffed cusps and mirrors, electrostatically assisted toroidal confinement), (6) the Migma concept, and (7) wall-confined plasmas. The plasma parameters of the devices are presented and the advantages and disadvantages of each are listed.

  10. Tandem mirror plasma confinement apparatus

    DOEpatents

    Fowler, T. Kenneth

    1978-11-14

    Apparatus and method for confining a plasma in a center mirror cell by use of two end mirror cells as positively charged end stoppers to minimize leakage of positive particles from the ends of the center mirror cell.

  11. Yukawa particles in a confining potential

    SciTech Connect

    Girotto, Matheus Levin, Yan; Santos, Alexandre P. dos; Colla, Thiago

    2014-07-07

    We study the density distribution of repulsive Yukawa particles confined by an external potential. In the weak coupling limit, we show that the mean-field theory is able to accurately account for the particle distribution. In the strong coupling limit, the correlations between the particles become important and the mean-field theory fails. For strongly correlated systems, we construct a density functional theory which provides an excellent description of the particle distribution, without any adjustable parameters.

  12. Neoclassical transport in enhanced confinement toroidal plasmas

    SciTech Connect

    Lin, Z.; Tang, W.M.; Lee, W.W.

    1996-11-01

    It has recently been reported that ion thermal transport levels in enhanced confinement tokamak plasmas have been observed to fall below the irreducible minimum level predicted by standard neoclassical theory. This apparent contradiction is resolved in the present analysis by relaxing the basic neoclassical assumption that the ions orbital excursions are much smaller than the local toroidal minor radius and the equilibrium scale lengths of the system.

  13. Alternative approaches to plasma confinement

    NASA Technical Reports Server (NTRS)

    Roth, J. R.

    1977-01-01

    The potential applications of fusion reactors, the desirable properties of reactors intended for various applications, and the limitations of the Tokamak concept are discussed. The principles and characteristics of 20 distinct alternative confinement concepts are described, each of which may be an alternative to the Tokamak. The devices are classed as Tokamak-like, stellarator-like, mirror machines, bumpy tori, electrostatically assisted, migma concept, and wall-confined plasma.

  14. Seizure induces activation of multiple subtypes of neural progenitors and growth factors in hippocampus with neuronal maturation confined to dentate gyrus

    SciTech Connect

    Indulekha, Chandrasekharan L.; Sanalkumar, Rajendran; Thekkuveettil, Anoopkumar; James, Jackson

    2010-03-19

    Adult hippocampal neurogenesis is altered in response to different physiological and pathological stimuli. GFAP{sup +ve}/nestin{sup +ve} radial glial like Type-1 progenitors are considered to be the resident stem cell population in adult hippocampus. During neurogenesis these Type-1 progenitors matures to GFAP{sup -ve}/nestin{sup +ve} Type-2 progenitors and then to Type-3 neuroblasts and finally differentiates into granule cell neurons. In our study, using pilocarpine-induced seizure model, we showed that seizure initiated activation of multiple progenitors in the entire hippocampal area such as DG, CA1 and CA3. Seizure induction resulted in activation of two subtypes of Type-1 progenitors, Type-1a (GFAP{sup +ve}/nestin{sup +ve}/BrdU{sup +ve}) and Type-1b (GFAP{sup +ve}/nestin{sup +ve}/BrdU{sup -ve}). We showed that majority of Type-1b progenitors were undergoing only a transition from a state of dormancy to activated form immediately after seizures rather than proliferating, whereas Type-1a showed maximum proliferation by 3 days post-seizure induction. Type-2 (GFAP{sup -ve}/nestin{sup +ve}/BrdU{sup +ve}) progenitors were few compared to Type-1. Type-3 (DCX{sup +ve}) progenitors showed increased expression of immature neurons only in DG region by 3 days after seizure induction indicating maturation of progenitors happens only in microenvironment of DG even though progenitors are activated in CA1 and CA3 regions of hippocampus. Also parallel increase in growth factors expression after seizure induction suggests that microenvironmental niche has a profound effect on stimulation of adult neural progenitors.

  15. An effective host material with thermally activated delayed fluorescence formed by confined conjugation for red phosphorescent organic light-emitting diodes.

    PubMed

    Liu, Xiang-Yang; Liang, Feng; Yuan, Yi; Cui, Lin-Song; Jiang, Zuo-Quan; Liao, Liang-Sheng

    2016-06-21

    A thermally activated delayed fluorescence material 2,6-bis(9,9-diphenylacridin-10(9H)-yl)pyrazine was designed and synthesized. The twisted configuration made it possesses very small singlet-triplet splitting. A red electroluminescent device based on this new host material is able to achieve ∼26% external quantum efficiency and relatively flat efficiency roll-off. PMID:27276277

  16. Institutional games played by confined juveniles.

    PubMed

    Bartollas, C; Sieverdes, C M

    1983-01-01

    This study examined the games played by 561 juvenile offenders confined in six coeducational correctional facilities in one state. The types of games these residents used against staff and peers within the confines of the institution varied considerably. The study documented nineteen games used by males and females, twelve to deal with staff and seven to deal with peers. The games were defined as therapeutic games, material games, psychological games, and physical games. Peer-oriented games included attention-seeking activities and a variety of dominance games. Additionally, these games were described and tabulated according to the sex and race of the residents. The conclusion was that game-playing behavior was no less frequent in coeducational institutions than it was in single-sex institutions. PMID:6650271

  17. Directed collective motion of bacteria under channel confinement

    NASA Astrophysics Data System (ADS)

    Wioland, H.; Lushi, E.; Goldstein, R. E.

    2016-07-01

    Dense suspensions of swimming bacteria are known to exhibit collective behaviour arising from the interplay of steric and hydrodynamic interactions. Unconfined suspensions exhibit transient, recurring vortices and jets, whereas those confined in circular domains may exhibit order in the form of a spiral vortex. Here we show that confinement into a long and narrow macroscopic ‘racetrack’ geometry stabilises bacterial motion to form a steady unidirectional circulation. This motion is reproduced in simulations of discrete swimmers that reveal the crucial role that bacteria-driven fluid flows play in the dynamics. In particular, cells close to the channel wall produce strong flows which advect cells in the bulk against their swimming direction. We examine in detail the transition from a disordered state to persistent directed motion as a function of the channel width, and show that the width at the crossover point is comparable to the typical correlation length of swirls seen in the unbounded system. Our results shed light on the mechanisms driving the collective behaviour of bacteria and other active matter systems, and stress the importance of the ubiquitous boundaries found in natural habitats.

  18. Activity systems in the inquiry classroom

    NASA Astrophysics Data System (ADS)

    Wortham, Donald William

    Inquiry science, as called for by reform-minded organizations such as the National Research Council (1996), offers a platform with the potential for introducing all students to the practice of science while maintaining focus on key concepts and theories. This project followed two small groups as they completed an inquiry unit on genetics at a Midwestern high school. I investigated whether levels of student-to-teacher, student-to-student, student-apparatus, and student-concept connections were approximately equal across all students in each of the two groups. I found differences among students in levels of student-to-teacher, student-to-student, and student-concept connections. From a situated idiopathic perspective, these differences may indicate different levels of opportunity-to-learn. At a more abstract (nomothetic) level, these differences may be due to emergent divisions of labor (roles) within the two groups. From the perspective of Activity Theory (Leont'ev, 1978; Engestrom, 1987), roles serve as important mediators that simultaneously allow the social unit to accomplish its objectives, while shaping the development of participants. I describe three roles that capture modes of participation for students interacting in the small groups, and that may contribute to what Engestrom (2001) calls subject-producing activity systems: networked contributor, social member, and isolate. This paper also describes tools for teachers and researchers to use in identifying levels of mediation and roles as they occur in small groups.

  19. ROVER: A prototype active vision system

    NASA Astrophysics Data System (ADS)

    Coombs, David J.; Marsh, Brian D.

    1987-08-01

    The Roving Eyes project is an experiment in active vision. We present the design and implementation of a prototype that tracks colored balls in images from an on-line charge coupled device (CCD) camera. Rover is designed to keep up with its rapidly changing environment by handling best and average case conditions and ignoring the worst case. This allows Rover's techniques to be less sophisticated and consequently faster. Each of Rover's major functional units is relatively isolated from the others, and an executive which knows all the functional units directs the computation by deciding which jobs would be most effective to run. This organization is realized with a priority queue of jobs and their arguments. Rover's structure not only allows it to adapt its strategy to the environment, but also makes the system extensible. A capability can be added to the system by adding a functional module with a well defined interface and by modifying the executive to make use of the new module. The current implementation is discussed in the appendices.

  20. Metal-organic frameworks as host materials of confined supercooled liquids

    NASA Astrophysics Data System (ADS)

    Fischer, J. K. H.; Sippel, P.; Denysenko, D.; Lunkenheimer, P.; Volkmer, D.; Loidl, A.

    2015-10-01

    In this work, we examine the use of metal-organic framework (MOF) systems as host materials for the investigation of glassy dynamics in confined geometry. We investigate the confinement of the molecular glass former glycerol in three MFU-type MOFs with different pore sizes (MFU stands for "Metal-Organic Framework Ulm-University") and study the dynamics of the confined liquid via dielectric spectroscopy. In accord with previous reports on confined glass formers, we find different degrees of deviations from bulk behavior depending on pore size, demonstrating that MOFs are well-suited host systems for confinement investigations.

  1. Zeolite-confined ruthenium(0) nanoclusters catalyst: record catalytic activity, reusability, and lifetime in hydrogen generation from the hydrolysis of sodium borohydride.

    PubMed

    Zahmakiran, Mehmet; Ozkar, Saim

    2009-03-01

    Sodium borohydride, NaBH4, has been considered the most attractive hydrogen-storage material for portable fuel cell applications, as it provides a safe and practical means of producing hydrogen. In a recent communication (Zahmakiran, M.; Ozkar, S. Langmuir 2008, 24, 7065), we have reported a record total turnover number (TTON) of 103 200 mol H2/mol Ru and turnover frequency (TOF) up to 33 000 mol H2/mol Ru x h obtained by using intrazeolite ruthenium(0) nanoclusters in the hydrolysis of sodium borohydride. Here we report full details of the kinetic studies on the intrazeolite ruthenium(0) nanoclusters catalyzed hydrolysis of sodium borohydride in both aqueous and basic solutions. Expectedly, the intrazeolite ruthenium(0) nanoclusters show unprecedented catalytic lifetime, TTON = 27 200 mol H2/mol Ru, and TOF up to 4000 mol H2/mol Ru x h in the hydrolysis of sodium borohydride in basic solution (5% wt NaOH) as well. More importantly, the intrazeolite ruthenium(0) nanoclusters are isolable, bottleable, redispersible, and yet catalytically active. They retain 76% or 61% of their initial catalytic activity at the fifth run with a complete release of hydrogen in aqueous and basic medium, respectively. The intrazeolite ruthenium(0) nanoclusters were isolated as black powder and characterized by using a combination of advanced analytical techniques including XRD, HRTEM, TEM-EDX, SEM, XPS, ICP-OES, and N2 adsorption. PMID:19437749

  2. DNA Confined in Nanochannels and Nanoslits

    NASA Astrophysics Data System (ADS)

    Tree, Douglas R.

    It has become increasingly apparent in recent years that next-generation sequencing (NGS) has a blind spot for large scale genomic variation, which is crucial for understanding the genotype-phenotype relationship. Genomic mapping methods attempt to overcome the weakesses of NGS by providing a coarse-grained map of the distances between restriction sites to aid in sequence assembly. From such methods, one hopes to realize fast and inexpensive de novo sequencing of human and plant genomes. One of the most promising methods for genomic mapping involves placing DNA inside a device only a few dozen nanometers wide called a nanochannel. A nanochannel stretches the DNA so that the distance between fluorescently labeled restriction sites can be measured en route to obtaining an accurate genome map. Unfortunately for those who wish to design devices, the physics of how DNA stretches when confined in a nanochannel is still an active area of research. Indeed, despite decades old theories from polymer physics regarding weakly and strongly stretched polymers, seminal experiments in the mid-2000s have gone unexplained until very recently. With a goal of creating a realistic engineering model of DNA in nanochannels, this dissertation addresses a number of important outstanding research topics in this area. We first discuss the physics of dilute solutions of DNA in free solution, which show distinctive behavior due to the stiff nature of the polymer. We then turn our attention to the equilibrium regimes of confined DNA and explore the effects of stiff chains and weak excluded volume on the confinement free energy and polymer extension. We also examine dynamic properties such as the diffusion coefficient and the characteristic relaxation time. Finally, we discuss a sister problem related to DNA confined in nanoslits, which shares much of the same physics as DNA confined in channels. Having done this, we find ourselves with a well-parameterized wormlike chain model that is

  3. Size scaling of microtubule asters in confinement

    NASA Astrophysics Data System (ADS)

    Pelletier, James; Field, Christine; Krutkramelis, Kaspars; Fakhri, Nikta; Oakey, John; Gatlin, Jay; Mitchison, Timothy

    Microtubule asters are radial arrays of microtubules (MTs) nucleated around organizing centers (MTOCs). Across a wide range of cell types and sizes, aster positioning influences cellular organization. To investigate aster size and positioning, we reconstituted dynamic asters in Xenopus cytoplasmic extract, confined in fluorous oil microfluidic emulsions. In large droplets, we observed centering of MTOCs. In small droplets, we observed a breakdown in natural positioning, with MTOCs at the droplet edge and buckled or bundled MTs along the interface. In different systems, asters are positioned by different forces, such as pushing due to MT polymerization, or pulling due to bulk or cortical dynein. To estimate different contributions to aster positioning, we biochemically perturbed dynactin function, or MT or actin polymerization. We used carbon nanotubes to measure molecular motions and forces in asters. These experimental results inform quantitative biophysical models of aster size and positioning in confinement. JFP was supported by a Fannie and John Hertz Graduate Fellowship.

  4. Acoustic trapping of active matter

    NASA Astrophysics Data System (ADS)

    Takatori, Sho C.; de Dier, Raf; Vermant, Jan; Brady, John F.

    2016-03-01

    Confinement of living microorganisms and self-propelled particles by an external trap provides a means of analysing the motion and behaviour of active systems. Developing a tweezer with a trapping radius large compared with the swimmers' size and run length has been an experimental challenge, as standard optical traps are too weak. Here we report the novel use of an acoustic tweezer to confine self-propelled particles in two dimensions over distances large compared with the swimmers' run length. We develop a near-harmonic trap to demonstrate the crossover from weak confinement, where the probability density is Boltzmann-like, to strong confinement, where the density is peaked along the perimeter. At high concentrations the swimmers crystallize into a close-packed structure, which subsequently `explodes' as a travelling wave when the tweezer is turned off. The swimmers' confined motion provides a measurement of the swim pressure, a unique mechanical pressure exerted by self-propelled bodies.

  5. Acoustic trapping of active matter.

    PubMed

    Takatori, Sho C; De Dier, Raf; Vermant, Jan; Brady, John F

    2016-01-01

    Confinement of living microorganisms and self-propelled particles by an external trap provides a means of analysing the motion and behaviour of active systems. Developing a tweezer with a trapping radius large compared with the swimmers' size and run length has been an experimental challenge, as standard optical traps are too weak. Here we report the novel use of an acoustic tweezer to confine self-propelled particles in two dimensions over distances large compared with the swimmers' run length. We develop a near-harmonic trap to demonstrate the crossover from weak confinement, where the probability density is Boltzmann-like, to strong confinement, where the density is peaked along the perimeter. At high concentrations the swimmers crystallize into a close-packed structure, which subsequently 'explodes' as a travelling wave when the tweezer is turned off. The swimmers' confined motion provides a measurement of the swim pressure, a unique mechanical pressure exerted by self-propelled bodies. PMID:26961816

  6. Precursor detonation wave development in ANFO due to aluminum confinement

    SciTech Connect

    Jackson, Scott I; Klyanda, Charles B; Short, Mark

    2010-01-01

    Detonations in explosive mixtures of ammonium-nitrate-fuel-oil (ANFO) confined by aluminum allow for transport of detonation energy ahead of the detonation front due to the aluminum sound speed exceeding the detonation velocity. The net effect of this energy transport on the detonation is unclear. It could enhance the detonation by precompressing the explosive near the wall. Alternatively, it could decrease the explosive performance by crushing porosity required for initiation by shock compression or destroying confinement ahead of the detonation. At present, these phenomena are not well understood. But with slowly detonating, non-ideal high explosive (NIHE) systems becoming increasing prevalent, proper understanding and prediction of the performance of these metal-confined NIHE systems is desirable. Experiments are discussed that measured the effect of this ANFO detonation energy transported upstream of the front by a 76-mm-inner-diameter aluminum confining tube. Detonation velocity, detonation-front shape, and aluminum response are recorded as a function of confiner wall thickness and length. Detonation shape profiles display little curvature near the confining surface, which is attributed to energy transported upstream modifying the flow. Average detonation velocities were seen to increase with increasing confiner thickness, while wavefront curvature decreased due to the stiffer, subsonic confinement. Significant radial sidewall tube motion was observed immediately ahead of the detonation. Axial motion was also detected, which interfered with the front shape measurements in some cases. It was concluded that the confiner was able to transport energy ahead of the detonation and that this transport has a definite effect on the detonation by modifying its characteristic shape.

  7. 2D Colloidal Wigner crystals in confined geometries

    NASA Astrophysics Data System (ADS)

    Higler, Ruben; Sprakel, Joris

    2015-03-01

    Crystallization of bulk systems has been widely studied using colloids as a model system. However, study into colloidal crystallization in confined geometries has been sparse and little is known about the effects of strong confinement on the dynamics of colloidal crystal. In our research we prepare 2D crystals from charged colloids in an apolar solvent to study crystal dynamics, formation, and structure in circular confinements. These confining geometries are made using softlithography techniques from SU-8. In order to broaden the parameter space we can reach in experiments we employ brownian dynamics simulations to supplement our experimental results. Using single-particle tracking we have subpixel resolution positional information of every particle in the system. We study the vibrational modes of our confined crystals and find well defined modes unique to confined systems, such as a radially symmetric compression (or breathing) mode, a collective rotation mode, and distinct resonance modes. Furthermore, due to the circular nature of our constrictions, defectless crystals are impossible, we find, for sufficiently high area fractions, that the defects order at well defined points at the edge. The effect of this ``defect-localization'' has a clear influence on the vibrational modes.

  8. Combinatorial regulation modules on GmSBP2 promoter: a distal cis-regulatory domain confines the SBP2 promoter activity to the vascular tissue in vegetative organs.

    PubMed

    Waclawovsky, Alessandro J; Freitas, Rejane L; Rocha, Carolina S; Contim, Luis Antônio S; Fontes, Elizabeth P B

    2006-01-01

    The Glycine max sucrose binding protein (GmSBP2) promoter directs phloem-specific expression of reporter genes in transgenic tobacco. Here, we identified cis-regulatory domains (CRD) that contribute with positive and negative regulation for the tissue-specific pattern of the GmSPB2 promoter. Negative regulatory elements in the distal CRD-A (-2000 to -700) sequences suppressed expression from the GmSBP2 promoter in tissues other than seed tissues and vascular tissues of vegetative organs. Deletion of this region relieved repression resulting in a constitutive promoter highly active in all tissues analyzed. Further deletions from the strong constitutive -700GmSBP2 promoter delimited several intercalating enhancer-like and repressing domains that function in a context-dependent manner. Histochemical examination revealed that the CRD-C (-445 to -367) harbors both negative and positive elements. This region abolished promoter expression in roots and in all tissues of stems except for the inner phloem. In contrast, it restores root meristem expression when fused to the -132pSBP2-GUS construct, which contains root meristem expression-repressing determinants mapped to the 44-bp CRD-G (-136 to -92). Thus, the GmSBP2 promoter is functionally organized into a proximal region with the combinatorial modular configuration of plant promoters and a distal domain, which restricts gene expression to the vascular tissues in vegetative organs. PMID:16574256

  9. Chemical reactions confined within carbon nanotubes.

    PubMed

    Miners, Scott A; Rance, Graham A; Khlobystov, Andrei N

    2016-08-22

    In this critical review, we survey the wide range of chemical reactions that have been confined within carbon nanotubes, particularly emphasising how the pairwise interactions between the catalysts, reactants, transition states and products of a particular molecular transformation with the host nanotube can be used to control the yields and distributions of products of chemical reactions. We demonstrate that nanoscale confinement within carbon nanotubes enables the control of catalyst activity, morphology and stability, influences the local concentration of reactants and products thus affecting equilibria, rates and selectivity, pre-arranges the reactants for desired reactions and alters the relative stability of isomeric products. We critically evaluate the relative advantages and disadvantages of the confinement of chemical reactions inside carbon nanotubes from a chemical perspective and describe how further developments in the controlled synthesis of carbon nanotubes and the incorporation of multifunctionality are essential for the development of this ever-expanding field, ultimately leading to the effective control of the pathways of chemical reactions through the rational design of multi-functional carbon nanoreactors. PMID:27301444

  10. Modeling the Effects of Confinement during Cookoff of Explosives

    NASA Astrophysics Data System (ADS)

    Hobbs, Michael

    2013-06-01

    In practical scenarios, cookoff of explosives is a three-dimensional transient phenomenon where the rate limiting reactions may occur either in the condensed or gas phase. The effects of confinement are more dramatic when the rate-limiting reactions occur in the gas phase. Explosives can be self-confined, where the decomposing gases are contained within non-permeable regions of the explosive, or confined by a metal or composite container. Self-confinement is prevalent in plastic bonded explosives at full density. The time-to-ignition can be delayed by orders of magnitude if the reactive gases leave the confining apparatus. Delays in ignition can also occur when the confining apparatus has excess gas volume or ullage. Explosives with low melting points, such as trinitrotoluene (TNT) or cyclotrimethylenetrinitramine (RDX) are complex since melting and flow need to be considered when simulating cookoff. Cookoff of composite explosives such as Comp-B (mixture of TNT and RDX) are even more complex since dissolution of one component increases the reactivity of the other component. Understanding the effects of confinement is required to accurately model cookoff at various scales ranging from small laboratory experiments to large real systems that contain explosives. Sandia National Laboratories is managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  11. Finite particle size drives defect-mediated domain structures in strongly confined colloidal liquid crystals

    PubMed Central

    Gârlea, Ioana C.; Mulder, Pieter; Alvarado, José; Dammone, Oliver; Aarts, Dirk G. A. L.; Lettinga, M. Pavlik; Koenderink, Gijsje H.; Mulder, Bela M.

    2016-01-01

    When liquid crystals are confined to finite volumes, the competition between the surface anchoring imposed by the boundaries and the intrinsic orientational symmetry-breaking of these materials gives rise to a host of intriguing phenomena involving topological defect structures. For synthetic molecular mesogens, like the ones used in liquid-crystal displays, these defect structures are independent of the size of the molecules and well described by continuum theories. In contrast, colloidal systems such as carbon nanotubes and biopolymers have micron-sized lengths, so continuum descriptions are expected to break down under strong confinement conditions. Here, we show, by a combination of computer simulations and experiments with virus particles in tailor-made disk- and annulus-shaped microchambers, that strong confinement of colloidal liquid crystals leads to novel defect-stabilized symmetrical domain structures. These finite-size effects point to a potential for designing optically active microstructures, exploiting the as yet unexplored regime of highly confined liquid crystals. PMID:27353002

  12. Psychological strain: examining the effect of hypoxic bedrest and confinement.

    PubMed

    Stavrou, Nektarios A M; McDonnell, Adam C; Eiken, Ola; Mekjavic, Igor B

    2015-02-01

    The aim was to assess the effect of a 10-day exposure to the environmental stressors anticipated in future lunar habitats on indices of psychological strain. In addition to the reduced gravity of the Moon, future habitats on the Moon will likely maintain a hypobaric hypoxic environment. The hypobaric environment will eliminate the need for long decompression profiles prior to each extra-vehicular activity. We investigated the indices of psychological strain during three 10-day conditions, designed to assess the separate and combined effects of inactivity/unloading and normobaric hypoxia on several physiological systems. Eleven male participants underwent three 10-day campaigns in a randomised manner: 1) normobaric normoxic bed rest (NBR), 2) normobaric hypoxic bed rest (HBR) and 3) normobaric hypoxic ambulatory confinement (HAMB). The most negative psychological profile appeared on day 10 of the HBR and HAMB (hypoxic) conditions. Concomitantly, a decrease in positive emotions was observed from baseline to day 10 of the HBR and NBR conditions. Thus, confinement in a hypoxic environment seems to exert a negative effect on an individual's psychological mood. PMID:25484354

  13. Immune responses in humans after 60 days of confinement

    NASA Technical Reports Server (NTRS)

    Schmitt, D. A.; Peres, C.; Sonnenfeld, G.; Tkackzuk, J.; Arquier, M.; Mauco, G.; Ohayon, E.

    1995-01-01

    A confinement experiment in a normobaric diving chamber was undertaken to better understand the effect of confinement and isolation on human psychology and physiology. Pre- and postconfinement blood samples were obtained from four test subjects and control donors to analyze immune responses. No modification in the levels of CD2+, CD3+, CD4+, CD8+, CD19+, and CD56+ cells was observed after confinement. Mitogen-induced T-lymphocyte proliferation and interleukin-2 receptor expression were not altered significantly. Whole blood interferon-alpha and gamma-induction and plasma cortisol levels were also unchanged, as was natural killer cell activity. These data suggest that in humans, no specific components of the immune response are affected by a 2-month isolation and confinement of a small group.

  14. CORRELATIONS IN CONFINED QUANTUM PLASMAS

    SciTech Connect

    DUFTY J W

    2012-01-11

    This is the final report for the project 'Correlations in Confined Quantum Plasmas', NSF-DOE Partnership Grant DE FG02 07ER54946, 8/1/2007 - 7/30/2010. The research was performed in collaboration with a group at Christian Albrechts University (CAU), Kiel, Germany. That collaboration, almost 15 years old, was formalized during the past four years under this NSF-DOE Partnership Grant to support graduate students at the two institutions and to facilitate frequent exchange visits. The research was focused on exploring the frontiers of charged particle physics evolving from new experimental access to unusual states associated with confinement. Particular attention was paid to combined effects of quantum mechanics and confinement. A suite of analytical and numerical tools tailored to the specific inquiry has been developed and employed

  15. Preliminary design activities for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Information on the development of solar heating and cooling systems is presented. The major emphasis is placed on program organization, system size definition, site identification, system approaches, heat pump and equipment design, collector procurement, and other preliminary design activities.

  16. Random Matrices in Non-confining Potentials

    NASA Astrophysics Data System (ADS)

    Allez, Romain; Dumaz, Laure

    2015-08-01

    We consider invariant matrix processes diffusing in non-confining cubic potentials of the form . We construct the trajectories of such processes for all time by restarting them whenever an explosion occurs, from a new (well chosen) initial condition, insuring continuity of the eigenvectors and of the non exploding eigenvalues. We characterize the dynamics of the spectrum in the limit of large dimension and analyze the stationary state of this evolution explicitly. We exhibit a sharp phase transition for the limiting spectral density at a critical value . If , then the potential presents a well near deep enough to confine all the particles inside, and the spectral density is supported on a compact interval. If however, the steady state is in fact dynamical with a macroscopic stationary flux of particles flowing across the system. We prove that this flux displays a second order phase transition at the critical value such that when where is an explicit constant. In the subcritical regime, the eigenvalues allocate according to a stationary density profile with full support in , flanked with heavy tails such that as . Our method applies to other non-confining potentials and we further investigate a family of quartic potentials, which were already studied in (Brezin et al. in Commun Math Phys 59:35-51, 1978) to count planar diagrams.

  17. A dual-well step drawdown method for the estimation of linear and non-linear flow parameters and wellbore skin factor in confined aquifer systems

    NASA Astrophysics Data System (ADS)

    Sethi, Rajandrea

    2011-03-01

    SummaryIn this study a method based on dual-well step drawdown test (i.e. a combination of an aquifer and a well performance test) for the determination of hydrodynamic parameters (namely storage coefficient and hydraulic conductivity), mechanical wellbore finite thickness skin factor, non-linear wellbore and non-linear aquifer parameters in an homogeneous confined aquifer is presented in order to put together aquifer and well tests. The interpretation procedure is based on the application of superposition principle to a large time logarithmic approximation of the solution. The advantages of this method, that can be considered an extension of Jacob step-test (1947) and Cooper-Jacob approximation (1946), are that: (I) it is possible to determine simultaneously aquifer and well properties in a single test; (II) the method is based on a large time approximation and it is therefore independent from wellbore storage; (III) if the well skin is absent, the aquifer parameters (storage coefficient and hydraulic conductivity) can be derived just from a single-well test; (IV) the interpretation procedure is easy to apply and robust and does not require any specific numeric code or software. The same procedure can be easily adapted to gas well testing. It is also shown that, even in the presence of linear and non-linear flow, skin effect and wellbore storage, the hydraulic conductivity (and not the storage coefficient) of the aquifer can be correctly estimated by the Cooper and Jacob (1946) method applied to a single-rate pumping test, using exclusively the large time drawdown data measured at the pumping well.

  18. Confined Visible Optical Tamm States

    NASA Astrophysics Data System (ADS)

    Feng, F.; Ouaret, K.; Portalupi, S.; Lafosse, X.; Nasilovski, M.; de Marcillac, W. Daney; Frigerio, J.-M.; Schwob, C.; Dubertret, B.; Maître, A.; Senellart, P.; Coolen, L.

    2016-05-01

    Optical Tamm states are two-dimensional (2D) electromagnetic modes propagating at the interface between a Bragg mirror and a metallic film. When a thin (a few tens of nm) metallic micron-radius disk is deposited on a Bragg mirror, optical Tamm states can be confined below the disk surface, creating a Tamm-states cavity. We describe here the photoluminescence properties of colloidal semiconductor nanocrystals embedded in a Tamm cavity. Tamm states confinement effects are demonstrated and analysed as a function of the disk diameter, and compared with finite-elements simulations.

  19. CONFINEMENT OF HIGH TEMPERATURE PLASMA

    DOEpatents

    Koenig, H.R.

    1963-05-01

    The confinement of a high temperature plasma in a stellarator in which the magnetic confinement has tended to shift the plasma from the center of the curved, U-shaped end loops is described. Magnetic means are provided for counteracting this tendency of the plasma to be shifted away from the center of the end loops, and in one embodiment this magnetic means is a longitudinally extending magnetic field such as is provided by two sets of parallel conductors bent to follow the U-shaped curvature of the end loops and energized oppositely on the inside and outside of this curvature. (AEC)

  20. Functional changes in neutrophils and psychoneuroendocrine responses during 105 days of confinement.

    PubMed

    Strewe, C; Muckenthaler, F; Feuerecker, M; Yi, B; Rykova, M; Kaufmann, I; Nichiporuk, I; Vassilieva, G; Hörl, M; Matzel, S; Schelling, G; Thiel, M; Morukov, B; Choukèr, A

    2015-05-01

    The innate immune system as one key element of immunity and a prerequisite for an adequate host defense is of emerging interest in space research to ensure crew health and thus mission success. In ground-based studies, spaceflight-associated specifics such as confinement caused altered immune functions paralleled by changes in stress hormone levels. In this study, six men were confined for 105 days to a space module of ~500 m(3) mimicking conditions of a long-term space mission. Psychic stress was surveyed by different questionnaires. Blood, saliva, and urine samples were taken before, during, and after confinement to determine quantitative and qualitative immune responses by analyzing enumerative assays and quantifying microbicide and phagocytic functions. Additionally, expression and shedding of L-selectin (CD62L) on granulocytes and different plasma cytokine levels were measured. Cortisol and catecholamine levels were analyzed in saliva and urine. Psychic stress or an activation of the psychoneuroendocrine system could not be testified. White blood cell counts were not significantly altered, but innate immune functions showed increased cytotoxic and reduced microbicide capabilities. Furthermore, a significantly enhanced shedding of CD62L might be a hint at increased migratory capabilities. However, this was observed in the absence of any acute inflammatory state, and no rise in plasma cytokine levels was detected. In summary, confinement for 105 days caused changes in innate immune functions. Whether these changes result from an alert immune state in preparation for further immune challenges or from a normal adaptive process during confinement remains to be clarified in future research. PMID:25678697

  1. Glassy dynamics of polymers confined to nanoporous glasses revealed by relaxational and scattering experiments.

    PubMed

    Schönhals, A; Goering, H; Schick, Ch; Frick, B; Zorn, R

    2003-09-01

    The glassy dynamics of poly(propylene glycol) (PPG) and poly(dimethyl siloxane) (PDMS) confined to a nanoporous host system revealed by dielectric spectroscopy, temperature-modulated DSC and neutron scattering is compared. For both systems the relaxation rates estimated from dielectric spectroscopy and temperature-modulated DSC agree quantitatively indicating that both experiments sense the glass transition. For PPG the segmental dynamics is determined by a counterbalance of adsorption and confinement effect. The former results form an interaction of the confined macromolecules with the internal surfaces. A confinement effect originates from an inherent length scale on which the underlying molecular motions take place. The increment of the specific-heat capacity [Formula: see text] at the glass transition vanishes at a finite length scale of 1.8 nm. Both results support the conception that a characteristic length scale is relevant for glassy dynamics. For PDMS only a confinement effect is observed which is much stronger than that for PPG. Down to a pore size of 7.5 nm, the temperature dependence of the relaxation times follows the Vogel-Fulcher-Tammann dependence. At a pore size of 5 nm this changes to an Arrhenius-like behaviour with a low activation energy. At the same pore size [Formula: see text] vanishes for PDMS. Quasielastic neutron scattering experiments reveal that also the diffusive character of the relevant molecular motions --found to be characteristic above the glass transition-- seems to disappear at this length scale. These results gives further strong support that the glass transition has to be characterised by an inherent length scale of the relevant molecular motions. PMID:15007697

  2. Building solids inside nano-space: from confined amorphous through confined solvate to confined 'metastable' polymorph.

    PubMed

    Nartowski, K P; Tedder, J; Braun, D E; Fábián, L; Khimyak, Y Z

    2015-10-14

    The nanocrystallisation of complex molecules inside mesoporous hosts and control over the resulting structure is a significant challenge. To date the largest organic molecule crystallised inside the nano-pores is a known pharmaceutical intermediate - ROY (259.3 g mol(-1)). In this work we demonstrate smart manipulation of the phase of a larger confined pharmaceutical - indomethacin (IMC, 357.8 g mol(-1)), a substance with known conformational flexibility and complex polymorphic behaviour. We show the detailed structural analysis and the control of solid state transformations of encapsulated molecules inside the pores of mesoscopic cellular foam (MCF, pore size ca. 29 nm) and controlled pore glass (CPG, pore size ca. 55 nm). Starting from confined amorphous IMC we drive crystallisation into a confined methanol solvate, which upon vacuum drying leads to the stabilised rare form V of IMC inside the MCF host. In contrast to the pure form, encapsulated form V does not transform into a more stable polymorph upon heating. The size of the constraining pores and the drug concentration within the pores determine whether the amorphous state of the drug is stabilised or it recrystallises into confined nanocrystals. The work presents, in a critical manner, an application of complementary techniques (DSC, PXRD, solid-state NMR, N2 adsorption) to confirm unambiguously the phase transitions under confinement and offers a comprehensive strategy towards the formation and control of nano-crystalline encapsulated organic solids. PMID:26280634

  3. Hybrid Silicon Nanophotonic Devices: Enhancing Light Emission, Modulation, and Confinement

    NASA Astrophysics Data System (ADS)

    Briggs, Ryan Morrow

    Silicon has become an increasingly important photonic material for communications, information processing, and sensing applications. Silicon is inexpensive compared to compound semiconductors, and it is well suited for confining and guiding light at standard telecommunication wavelengths due to its large refractive index and minimal intrinsic absorption. Furthermore, silicon-based optical devices can be fabricated alongside microelectronics while taking advantage of advanced silicon processing technologies. In order to realize complete chip-based photonic systems, certain critical components must continue to be developed and refined on the silicon platform, including compact light sources, modulators, routers, and sensing elements. However, bulk silicon is not necessarily an ideal material for many active devices because of its meager light emission characteristics, limited refractive index tunability, and fundamental limitations in confining light beyond the diffraction limit. In this thesis, we present three examples of hybrid devices that use different materials to bring additional optical functionality to silicon photonics. First, we analyze high-index-contrast silicon slot waveguides and their integration with light-emitting erbium-doped glass materials. Theoretical and experimental results show significant enhancement of spontaneous emission rates in slot structures. We then demonstrate the integration of vanadium dioxide, a thermochromic phase-change material, with silicon waveguides to form micron-scale absorption modulators. It is shown experimentally that a 2-mum long waveguide-integrated device exhibits broadband modulation of more than 6.5 dB at wavelengths near 1550 nm. Finally, we demonstrate polymer-on-gold dielectric-loaded surface-plasmon waveguides and ring resonators coupled to silicon waveguides with 1.0+/-0.1 dB insertion loss. The plasmonic waveguides are shown to support a single surface mode at telecommunication wavelengths, with strong

  4. Confinement as a Tool to Probe Amorphous Order

    NASA Astrophysics Data System (ADS)

    Cammarota, Chiara; Gradenigo, Giacomo; Biroli, Giulio

    2013-09-01

    We study the effect of confinement on glassy liquids using random first order transition theory as a framework. We show that the characteristic length scale above which confinement effects become negligible is related to the point-to-set length scale introduced to measure the spatial extent of amorphous order in supercooled liquids. By confining below this characteristic size, the system becomes a glass. Eventually, for very small sizes, the effect of the boundary is so strong that any collective glassy behavior is wiped out. We clarify similarities and differences between the physical behaviors induced by confinement and by pinning particles outside a spherical cavity (the protocol introduced to measure the point-to-set length). Finally, we discuss possible numerical and experimental tests of our predictions.

  5. Activity Systems and Moral Reasoning: An Intervention Study

    ERIC Educational Resources Information Center

    Wardi, Eva; Helkama, Klaus

    2015-01-01

    Seventeen social educator students were taught to analyze their work activity by means of a Vygotsky-inspired method, drawing on Engeström's notion of an activity system. The method aimed at increasing the consciousness of the students of the structure of work activity system. The participants wrote two accounts of their field-work practice…

  6. Statistical Contact Model for Confined Molecules

    NASA Astrophysics Data System (ADS)

    Santamaria, Ruben; de la Paz, Antonio Alvarez; Roskop, Luke; Adamowicz, Ludwik

    2016-06-01

    A theory that describes in a realistic form a system of atoms under the effects of temperature and confinement is presented. The theory departs from a Lagrangian of the Zwanzig type and contains the main ingredients for describing a system of atoms immersed in a heat bath that is also formed by atoms. The equations of motion are derived according to Lagrangian mechanics. The application of statistical mechanics to describe the bulk effects greatly reduces the complexity of the equations. The resultant equations of motion are of the Langevin type with the viscosity and the temperature of the heat reservoir able to influence the trajectories of the particles. The pressure effects are introduced mechanically by using a container with an atomic structure immersed in the heat bath. The relevant variables that determine the equation of state are included in the formulation. The theory is illustrated by the derivation of the equation of state for a system with 76 atoms confined inside of a 180-atom fullerene-like cage that is immersed in fluid forming the heat bath at a temperature of 350 K and with the friction coefficient of 3.0 {ps}^{-1} . The atoms are of the type believed to form the cores of the Uranus and Neptune planets. The dynamic and the static pressures of the confined system are varied in the 3-5 KBar and 2-30 MBar ranges, respectively. The formulation can be equally used to analyze chemical reactions under specific conditions of pressure and temperature, determine the structure of clusters with their corresponding equation of state, the conditions for hydrogen storage, etc. The theory is consistent with the principles of thermodynamics and it is intrinsically ergodic, of general use, and the first of this kind.

  7. Statistical Contact Model for Confined Molecules

    NASA Astrophysics Data System (ADS)

    Santamaria, Ruben; de la Paz, Antonio Alvarez; Roskop, Luke; Adamowicz, Ludwik

    2016-08-01

    A theory that describes in a realistic form a system of atoms under the effects of temperature and confinement is presented. The theory departs from a Lagrangian of the Zwanzig type and contains the main ingredients for describing a system of atoms immersed in a heat bath that is also formed by atoms. The equations of motion are derived according to Lagrangian mechanics. The application of statistical mechanics to describe the bulk effects greatly reduces the complexity of the equations. The resultant equations of motion are of the Langevin type with the viscosity and the temperature of the heat reservoir able to influence the trajectories of the particles. The pressure effects are introduced mechanically by using a container with an atomic structure immersed in the heat bath. The relevant variables that determine the equation of state are included in the formulation. The theory is illustrated by the derivation of the equation of state for a system with 76 atoms confined inside of a 180-atom fullerene-like cage that is immersed in fluid forming the heat bath at a temperature of 350 K and with the friction coefficient of 3.0 {ps}^{-1}. The atoms are of the type believed to form the cores of the Uranus and Neptune planets. The dynamic and the static pressures of the confined system are varied in the 3-5 KBar and 2-30 MBar ranges, respectively. The formulation can be equally used to analyze chemical reactions under specific conditions of pressure and temperature, determine the structure of clusters with their corresponding equation of state, the conditions for hydrogen storage, etc. The theory is consistent with the principles of thermodynamics and it is intrinsically ergodic, of general use, and the first of this kind.

  8. New approaches to enhance active steering system functionalities: preliminary results

    NASA Astrophysics Data System (ADS)

    Serarslan, Benan

    2014-09-01

    An important development of the steering systems in general is active steering systems like active front steering and steer-by-wire systems. In this paper the current functional possibilities in application of active steering systems are explored. A new approach and additional functionalities are presented that can be implemented to the active steering systems without additional hardware such as new sensors and electronic control units. Commercial active steering systems are controlling the steering angle depending on the driving situation only. This paper introduce methods for enhancing active steering system functionalities depending not only on the driving situation but also vehicle parameters like vehicle mass, tyre and road condition. In this regard, adaptation of the steering ratio as a function of above mentioned vehicle parameters is presented with examples. With some selected vehicle parameter changes, the reduction of the undesired influences on vehicle dynamics of these parameter changes has been demonstrated theoretically with simulations and with real-time driving measurements.

  9. Process of activation of a palladium catalyst system

    DOEpatents

    Sobolevskiy, Anatoly; Rossin, Joseph A.; Knapke, Michael J.

    2011-08-02

    Improved processes for activating a catalyst system used for the reduction of nitrogen oxides are provided. In one embodiment, the catalyst system is activated by passing an activation gas stream having an amount of each of oxygen, water vapor, nitrogen oxides, and hydrogen over the catalyst system and increasing a temperature of the catalyst system to a temperature of at least 180.degree. C. at a heating rate of from 1-20.degree./min. Use of activation processes described herein leads to a catalyst system with superior NOx reduction capabilities.

  10. Limiting Spectra from Confining Potentials.

    ERIC Educational Resources Information Center

    Nieto, Michael Martin; Simmons, L. M., Jr.

    1979-01-01

    The author explains that, for confining potentials and large quantum numbers, the bound-state energies rise more rapidly as a function of n the more rapidly the potential rises with distance. However, the spectrum can rise no faster than n squared in the nonrelativistic case, or n in the relativistic case. (Author/GA)

  11. Dirac equations with confining potentials

    NASA Astrophysics Data System (ADS)

    Noble, J. H.; Jentschura, U. D.

    2015-01-01

    This paper is devoted to a study of relativistic eigenstates of Dirac particles which are simultaneously bound by a static Coulomb potential and added linear confining potentials. Under certain conditions, despite the addition of radially symmetric, linear confining potentials, specific bound-state energies surprisingly preserve their exact Dirac-Coulomb values. The generality of the "preservation mechanism" is investigated. To this end, a Foldy-Wouthuysen transformation is used to calculate the corrections to the spin-orbit coupling induced by the linear confining potentials. We find that the matrix elements of the effective operators obtained from the scalar, and time-like confining potentials mutually cancel for specific ratios of the prefactors of the effective operators, which must be tailored to the preservation mechanism. The result of the Foldy-Wouthuysen transformation is used to verify that the preservation is restricted (for a given Hamiltonian) to only one reference state, rather than traceable to a more general relationship among the obtained effective low-energy operators. The results derived from the nonrelativistic effective operators are compared to the fully relativistic radial Dirac equations. Furthermore, we show that the preservation mechanism does not affect antiparticle (negative-energy) states.

  12. Momentum Confinement at Low Torque

    SciTech Connect

    Solomon, W M; Burrell, K H; deGrassie, J S; Budny, R; Groebner, R J; Heidbrink, W W; Kinsey, J E; Kramer, G J; Makowski, M A; Mikkelsen, D; Nazikian, R; Petty, C C; Politzer, P A; Scott, S D; Van Zeeland, M A; Zarnstorff, M C

    2007-06-26

    Momentum confinement was investigated on DIII-D as a function of applied neutral beam torque at constant normalized {beta}{sub N}, by varying the mix of co (parallel to the plasma current) and counter neutral beams. Under balanced neutral beam injection (i.e. zero total torque to the plasma), the plasma maintains a significant rotation in the co-direction. This 'intrinsic' rotation can be modeled as being due to an offset in the applied torque (i.e. an 'anomalous torque'). This anomalous torque appears to have a magnitude comparable to one co-neutral beam source. The presence of such an anomalous torque source must be taken into account to obtain meaningful quantities describing momentum transport, such as the global momentum confinement time and local diffusivities. Studies of the mechanical angular momentum in ELMing H-mode plasmas with elevated q{sub min} show that the momentum confinement time improves as the torque is reduced. In hybrid plasmas, the opposite effect is observed, namely that momentum confinement improves at high torque/rotation. The relative importance of E x B shearing between the two is modeled using GLF23 and may suggest a possible explanation.

  13. Inertial Confinement Fusion Target Component Fabrication and Technology Development Support

    SciTech Connect

    Steinman, D.

    1993-03-01

    On December 31, 1990, the US Department of Energy entered into a contract with General Atomics (GA) to be the Inertial Confinement Fusion (ICF) Target Component Fabrication and Technology Development Support contractor. This report documents the technical activities of the period January 1, 1991 through September 30, 1992. During this period, GA was assigned 15 tasks in support of the Inertial Confinement Fusion program and its laboratories. These tasks included Facilities Activation, Staff Development, and Capabilities Validation to establish facilities and equipment, and demonstrate capability to perform ICF target fabrication research, development and production activities. The capabilities developed and demonstrated are those needed for fabrication and precise characterization of polymer shells and polymer coatings. We made progress toward production capability for glass shells, barrier layer coatings, and gas idling of shells. We fabricated over 1000 beam diagnostic foil targets for Sandia National Laboratory Albuquerque and provided full-time on-site engineering support for target fabrication and characterization. We initiated development of methods to fabricate polymer shells by a controlled mass microencapsulation technique, and performed chemical syntheses of several chlorine- and silicon-doped polymer materials for the University of Rochester's Laboratory for Laser Energetics (UR/LLE). We performed the conceptual design of a cryogenic target handling system for UR/LLE that will fill, transport, layer, and characterize targets filled with cryogenic deuterium or deuterium-tritium fuel, and insert these cryogenic targets into the OMEGA-Upgrade target chamber for laser implosion experiments. This report summarizes and documents the technical progress made on these tasks.

  14. Student Activity Funds: Creating a System of Controls That Work.

    ERIC Educational Resources Information Center

    Cuzzetto, Charles

    1995-01-01

    Although student-activity funds usually represent a small portion of school-system monies, their very nature makes them a high risk. Outlines three steps for maintaining an efficient and effective system of controls over student-activity funds: (1) identifying control issues; (2) designing a control system; and (3) using checks and balances.…

  15. Velocity alignment leads to high persistence in confined cells.

    PubMed

    Camley, Brian A; Rappel, Wouter-Jan

    2014-06-01

    Many cell types display random motility on two-dimensional substrates but crawl persistently in a single direction when confined in a microchannel or on an adhesive micropattern. Does this imply that the motility mechanism of confined cells is fundamentally different from that of unconfined cells? We argue that both free- and confined-cell migration may be described by a generic model of cells as "velocity-aligning" active Brownian particles previously proposed to solve a completely separate problem in collective cell migration. Our model can be mapped to a diffusive escape over a barrier and analytically solved to determine the cell's orientation distribution and repolarization rate. In quasi-one-dimensional confinement, velocity-aligning cells maintain their direction for times that can be exponentially larger than their persistence time in the absence of confinement. Our results suggest an important connection between single- and collective-cell migration: high persistence in confined cells corresponds with fast alignment of velocity to cell-cell forces. PMID:25019812

  16. FINE STRUCTURES AND OVERLYING LOOPS OF CONFINED SOLAR FLARES

    SciTech Connect

    Yang, Shuhong; Zhang, Jun; Xiang, Yongyuan

    2014-10-01

    Using the Hα observations from the New Vacuum Solar Telescope at the Fuxian Solar Observatory, we focus on the fine structures of three confined flares and the issue why all the three flares are confined instead of eruptive. All the three confined flares take place successively at the same location and have similar morphologies, so can be termed homologous confined flares. In the simultaneous images obtained by the Solar Dynamics Observatory, many large-scale coronal loops above the confined flares are clearly observed in multi-wavelengths. At the pre-flare stage, two dipoles emerge near the negative sunspot, and the dipolar patches are connected by small loops appearing as arch-shaped Hα fibrils. There exists a reconnection between the small loops, and thus the Hα fibrils change their configuration. The reconnection also occurs between a set of emerging Hα fibrils and a set of pre-existing large loops, which are rooted in the negative sunspot, a nearby positive patch, and some remote positive faculae, forming a typical three-legged structure. During the flare processes, the overlying loops, some of which are tracked by activated dark materials, do not break out. These direct observations may illustrate the physical mechanism of confined flares, i.e., magnetic reconnection between the emerging loops and the pre-existing loops triggers flares and the overlying loops prevent the flares from being eruptive.

  17. Active fluidization in dense glassy systems.

    PubMed

    Mandal, Rituparno; Bhuyan, Pranab Jyoti; Rao, Madan; Dasgupta, Chandan

    2016-07-20

    Dense soft glasses show strong collective caging behavior at sufficiently low temperatures. Using molecular dynamics simulations of a model glass former, we show that the incorporation of activity or self-propulsion, f0, can induce cage breaking and fluidization, resulting in the disappearance of the glassy phase beyond a critical f0. The diffusion coefficient crosses over from being strongly to weakly temperature dependent as f0 is increased. In addition, we demonstrate that activity induces a crossover from a fragile to a strong glass and a tendency of active particles to cluster. Our results are of direct relevance to the collective dynamics of dense active colloidal glasses and to recent experiments on tagged particle diffusion in living cells. PMID:27380935

  18. Active vibration control of lightweight floor systems

    NASA Astrophysics Data System (ADS)

    Baader, J.; Fontana, M.

    2016-04-01

    Wide-span and lightweight floors are often prone to structural vibrations due to their low resonance frequency and poor material damping. Their dynamic behaviour can be improved using passive, semi-active or active vibration control devices. The following article proposes a novel method for the controller synthesis for active vibration control. An existing passive TMD (tuned mass damper) is modelled and equipped with an actuator in order to provide more efficient damping. Using an iterative optimization approach under constraints, an optimal controller is found which minimizes a quadratic cost function in frequency domain. A simulation of an existing test bench shows that the active vibration control device is able to provide increased damping compared to the passive TMD.

  19. Correlation studies in weakly confining quantum dot potentials

    NASA Astrophysics Data System (ADS)

    Kimani, Peter; Jones, Preston; Winkler, Peter

    We investigate the electron correlation in few-electron closed-shell atomic systems and similarly in few-electron quantum dots under weak confinement. As usual we start with restricted Hartree-Fock (HF) calculations and add electron correlation in steps in a series of approximations based on the single particle Green's function approach: (i) second-order Green function (GF); (ii) 2ph-Tamm-Dancoff approximation (TDA); and (iii) an extended version thereof which introduces ground-state correlation into the TDA. Our studies exhibit similarities and differences between weakly confined quantum dots and standard atomic systems. The calculations support the application of HF, GF, and TDA techniques in the modeling of three-dimensional quantum dot systems. The observed differences emphasize the significance of confinement and electronic features unique to quantum dots, such as the increased binding of electrons with higher angular momentum and thus - compared to atomic systems - modified shell-filling sequences.

  20. Power System Considerations and Test Activities

    NASA Technical Reports Server (NTRS)

    Miller, J.

    1983-01-01

    The potential benefits of an IPACS system compared to NiCd and/or Regen Fuel Cell systems are summarized. The benefits are: (1) significant life cycle cost savings; (2) total weight to orbit savings (30 yrs) as much as 10 times; (3) end to end efficiency increase results in approximately 10 kW reduction in array size(6%); (4) motor/generator controller regulation during discharge simplifies distribution system; and (5) momentum stored for attitude control increased by 4 times.

  1. Toward fundamentals of confined catalysis in carbon nanotubes.

    PubMed

    Xiao, Jianping; Pan, Xiulian; Guo, Shujing; Ren, Pengju; Bao, Xinhe

    2015-01-14

    An increasing number of experimental studies have demonstrated that metal or metal oxide nanoparticles confined inside carbon nanotubes (CNTs) exhibit different catalytic activities with respect to the same metals deposited on the CNT exterior walls, with some reactions enhanced and others hindered. In this article, we describe the concept of confinement energy, which enables prediction of confinement effects on catalytic activities in different reactions. Combining density functional theory calculations and experiments by taking typical transition metals such as Fe, FeCo, RhMn, and Ru as models, we observed stronger strains and deformations within the CNT channels due to different electronic structures and spatial confinement. This leads to downshifted d-band states, and consequently the adsorption of molecules such as CO, N2, and O2 is weakened. Thus, the confined space of CNTs provides essentially a unique microenvironment due to the electronic effects, which shifts the volcano curve of the catalytic activities toward the metals with higher binding energies. The extent of the shift depends on the specific metals and the CNT diameters. This concept generalizes the diverse effects observed in experiments for different reactions, and it is anticipated to be applicable to an even broader range of reactions other than redox of metal species, CO hydrogenation, ammonia synthesis and decomposition discussed here. PMID:25496137

  2. Configurational temperature profile in confined fluids. II. Molecular fluids

    NASA Astrophysics Data System (ADS)

    Delhommelle, Jerome; Evans, Denis J.

    2001-04-01

    In an earlier paper, we applied configurational expressions of the temperature to the calculation of temperature profiles within a confined atomic fluid. This paper focuses on the application of these expressions to confined molecular fluids using ethane and hexane as examples. We first give configurational expressions for the temperature for these constrained systems. The configurational temperature profiles so obtained are compared to the kinetic temperature calculated using the equipartition principle, in equilibrium systems. These expressions are then used in nonequilibrium molecular dynamics (NEMD) simulations of fluids undergoing planar Poiseuille flow. We show that these configurational expressions provide a direct and accurate determination of the temperature profile for these systems.

  3. The Texas Experimental Tokamak: A plasma research facility. A proposal submitted to the Department of Energy in response to Program Notice 95-10: Innovations in toroidal magnetic confinement systems

    SciTech Connect

    1995-06-12

    The Fusion Research Center (FRC) at the University Texas will operate the tokamak TEXT-U and its associated systems for experimental research in basic plasma physics. While the tokamak is not innovative, the research program, diagnostics and planned experiments are. The fusion community will reap the benefits of the success in completing the upgrades (auxiliary heating, divertor, diagnostics, wall conditioning), developing diverted discharges in both double and single null configurations, exploring improved confinement regimes including a limiter H-mode, and developing unique, critical turbulence diagnostics. With these new regimes, the authors are poised to perform the sort of turbulence and transport studies for which the TEXT group has distinguished itself and for which the upgrade was intended. TEXT-U is also a facility for collaborators to perform innovative experiments and develop diagnostics before transferring them to larger machines. The general philosophy is that the understanding of plasma physics must be part of any intelligent fusion program, and that basic experimental research is the most important part of any such program. The emphasis of the proposed research is to provide well-documented plasmas which will be used to suggest and evaluate theories, to explore control techniques, to develop advanced diagnostics and analysis techniques, and to extend current drive techniques. Up to 1 MW of electron cyclotron heating (ECH) will be used not only for heating but as a localized, perturbative tool. Areas of proposed research are: (1) core turbulence and transport; (2) edge turbulence and transport; (3) turbulence analysis; (4) improved confinement; (5) ECH physics; (6) Alfven wave current drive; and (7) diagnostic development.

  4. Relaxation dynamics of deeply supercooled confined water in L,L-diphenylalanine micro/nanotubes.

    PubMed

    Ferreira, P M G L; Ishikawa, M S; Kogikoski, S; Alves, W A; Martinho, H

    2015-12-28

    The temperature dependence (10-290 K) of the low-frequency (20-150 cm(-1)) Raman-active phonon modes of deeply supercooled confined water in L,L-diphenylalanine micro/nanotubes was analyzed. The isolated dynamics of a specific geometry of a water cluster (pentamer) in a supercooled confined regime was studied in detail. A fragile-to-strong transition at 204 K was observed and related to the crossing of the Widom line. Analysis of peptide vibrational modes coupled to water hydrogen bonds indicated that hydrogen bond fluctuations play an irrelevant role in this system. Our results are in agreement with the second critical point of water existence hypothesis. PMID:26088917

  5. Dynamics of Confined Water Molecules in Aqueous Salt Hydrates

    SciTech Connect

    Werhahn, Jasper C.; Pandelov, S.; Yoo, Soohaeng; Xantheas, Sotiris S.; Iglev, H.

    2011-04-01

    The unusual properties of water are largely dictated by the dynamics of the H bond network. A single water molecule has more H bonding sites than atoms, hence new experimental and theoretical investigations about this peculiar liquid have not ceased to appear. Confinement of water to nanodroplets or small molecular clusters drastically changes many of the liquid’s properties. Such confined water plays a major role in the solvation of macro molecules such as proteins and can even be essential to their properties. Despite the vast results available on bulk and confined water, discussions about the correlation between spectral and structural properties continue to this day. The fast relaxation of the OH stretching vibration in bulk water, and the variance of sample geometries in the experiments on confined water obfuscate definite interpretation of the spectroscopic results in terms of structural parameters. We present first time-resolved investigations on a new model system that is ideally suited to overcome many of the problems faced in spectroscopical investigation of the H bond network of water. Aqueous hydrates of inorganic salts provide water molecules in a crystal grid, that enables unambiguous correlations of spectroscopic and structural features. Furthermore, the confined water clusters are well isolated from each other in the crystal matrix, so different degrees of confinement can be achieved by selection of the appropriate salt.

  6. Glassy dynamics in a confined monatomic fluid

    NASA Astrophysics Data System (ADS)

    Krishnan, S. H.; Ayappa, K. G.

    2012-07-01

    Molecular dynamic simulations of a strongly inhomogeneous system reveals that a single-component soft-sphere fluid can behave as a fragile glass former due to confinement. The self-intermediate scattering function, Fs(k,t), of a Lennard-Jones fluid confined in slit-shaped pores, which can accomodate two to four fluid layers, exhibits a two-step relaxation at moderate temperatures. The mean-squared displacement data are found to follow time-temperature superposition and both the self-diffusivity and late α relaxation times exhibit power-law divergences as the fluid is cooled. The system possesses a crossover temperature and follows the scalings of mode coupling theory for the glass transition. The temperature dependence of the self-diffusivity can be expressed using the Vogel-Fulcher-Tammann equation, and estimates of the fragility index of the system indicates a fragile glass former. At lower temperatures, signatures of additional relaxation processes are observed in the various dynamical quantities with a three-step relaxation observed in the Fs(k,t).

  7. Confined PBX 9501 gap reinitiation studies

    SciTech Connect

    Salyer, Terry R; Hill, Larry G; Lam, Kin

    2009-01-01

    For explosive systems that exhibit gaps or cracks between their internal components (either by design or mechanical failure), measurable time delays exist for detonation waves crossing them. Reinitiation across such gaps is dependent on the type of explosive, gap width, gap morphology, confinement, and temperature effects. To examine this reinitiation effect, a series of tests has been conducted to measure the time delay across a prescribed gap within an 'infinitely' confined PBX 9501 system. Detonation breakout along the explosive surface is measured with a streak camera, and flow features are examined during reinitiation near the gap. Such tests allow for quantitative determination of the time delay corresponding to the time of initiation across a given gap oriented normal to the direction of the detonation wave. Measured time delays can be compared with numerical calculations, making it possible to validate initiation models as well as estimate detonation run-up distances. Understanding this reinitiation behavior is beneficial for the design and evaluation of explosive systems that require precision timing and performance.

  8. Description of data base management systems activities

    NASA Technical Reports Server (NTRS)

    1983-01-01

    One of the major responsibilities of the JPL Computing and Information Services Office is to develop and maintain a JPL plan for providing computing services to the JPL management and administrative community that will lead to improved productivity. The CISO plan to accomplish this objective has been titled 'Management and Administrative Support Systems' (MASS). The MASS plan is based on the continued use of JPL's IBM 3032 Computer system for administrative computing and for the MASS functions. The current candidate administrative Data Base Management Systems required to support the MASS include ADABASE, Cullinane IDMS and TOTAL. Previous uses of administrative Data Base Systems have been applied to specific local functions rather than in a centralized manner with elements common to the many user groups. Limited capacity data base systems have been installed in microprocessor based office automation systems in a few Project and Management Offices using Ashton-Tate dBASE II. These experiences plus some other localized in house DBMS uses have provided an excellent background for developing user and system requirements for a single DBMS to support the MASS program.

  9. Hybrid energy storage systems utilizing redox active organic compounds

    DOEpatents

    Wang, Wei; Xu, Wu; Li, Liyu; Yang, Zhenguo

    2015-09-08

    Redox flow batteries (RFB) have attracted considerable interest due to their ability to store large amounts of power and energy. Non-aqueous energy storage systems that utilize at least some aspects of RFB systems are attractive because they can offer an expansion of the operating potential window, which can improve on the system energy and power densities. One example of such systems has a separator separating first and second electrodes. The first electrode includes a first current collector and volume containing a first active material. The second electrode includes a second current collector and volume containing a second active material. During operation, the first source provides a flow of first active material to the first volume. The first active material includes a redox active organic compound dissolved in a non-aqueous, liquid electrolyte and the second active material includes a redox active metal.

  10. Experimental acquisition system for impedance tomography with active electrode approach.

    PubMed

    Rigaud, B; Shi, Y; Chauveau, N; Morucci, J P

    1993-11-01

    An experimental system for impedance tomography has been constructed. The acquisition system uses 16 multifunctional active electrodes, each including a current source and a voltage buffer. Images of active and reactive parts of different target impedances in a phantom filled with liquid have been obtained. The system performance has been compared with those of other systems using either a mesh phantom or rods as point sources used for the determination of the modulation transfer function. PMID:8145585

  11. An Integrated Geospatial System for earthquake precursors assessment in Vrancea tectonic active zone in Romania

    NASA Astrophysics Data System (ADS)

    Zoran, Maria A.; Savastru, Roxana S.; Savastru, Dan M.

    2015-10-01

    With the development of space-based technologies to measure surface geophysical parameters and deformation at the boundaries of tectonic plates and large faults, earthquake science has entered a new era. Using time series satellite data for earthquake prediction, it is possible to pursue the behaviors of earthquake precursors in the future and to announce early warnings when the differences between the predicted value and the observed value exceed the pre-define threshold value. Starting with almost one week prior to a moderate or strong earthquake a transient thermal infrared rise in LST of several Celsius degrees (oC) and the increased OLR values higher than the normal have been recorded around epicentral areas, function of the magnitude and focal depth, which disappeared after the main shock. Also are recorded associated geomagnetic and ionospheric distrurbances. Vrancea tectonic active zone in Romania is characterized by a high seismic hazard in European- Mediterranean region, being responsible of strong or moderate intermediate depth and normal earthquakes generation on a confined epicentral area. Based on recorded geophysical parameters anomalies was developed an integrated geospatial system for earthquake precursors assessment in Vrancea active seismic zone. This system integrates derived from time series MODIS Terra/Aqua, NOAA-AVHRR, ASTER, Landsat TM/ETM satellite data multi geophysical parameters (land surface temperature -LST, outgoing long-wave radiation- OLR, and mean air temperature- AT as well as geomagnetic and ionospheric data in synergy with in-situ data for surveillance and forecasting of seismic events.

  12. Practical engineering: control of active systems using the stagnation temperature

    SciTech Connect

    Lunde, P.J.

    1982-04-01

    Solar active systems with flat plate collectors are discussed with reference to the temperature at which the system should be activated. It is concluded that the system should be activated when the stagnation temperature (temperature under the absorber plate when no fluid is circulating) equals the temperature of the fluid in storage. A thermistor Wheatstone bridge control system is described which will eliminate pump relay chatter and the permissible control differential is calculated from the collector efficiency curve. To avoid dedication of an entire collector to house the control system, a method is described for determining the stagnation temperature using a portion of an active collector. For an active solar hot water system, a calculation is carried out to show that a 2/sup 0/F temperature differential (stagnation temperature-storage temperature) is satisfactory. (MJJ)

  13. Electricity/Electronics Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Sutherland, Barbara, Ed.

    This electricity/electronics guide provides teachers with learning activities for secondary students. Introductory materials include an instructional planning outline and worksheet, an outline of essential elements, a list of objectives, a course description, and a content outline. The guide contains 35 modules on the following topics: electrical…

  14. Influence of confinement on thermodiffusion

    NASA Astrophysics Data System (ADS)

    Hannaoui, Rachid; Galliero, Guillaume; Hoang, Hai; Boned, Christian

    2013-09-01

    This work focuses on a possible influence of a nanoporous medium on the thermodiffusion of a fluid "isotopic" mixture. To do so, we performed molecular dynamics simulations of confined Lennard-Jones binary equimolar mixtures using grand-canonical like and non-equilibrium approaches in sub- and super-critical conditions. The study was conducted in atomistic slit pore of three adsorbent natures for various widths (from 5 to 35 times the size of a molecule). The simulation results indicate that for all thermodynamic conditions and whatever the pore characteristics, the confinement has a negligible effect on the thermal diffusion factor/Soret coefficient. However, when considered separately, the mass diffusion and thermodiffusion coefficients have been found to be largely influenced by the pore characteristics. These two coefficients decrease noticeably when adsorption is stronger and pore width smaller, a behavior that is consistent with a simple hydrodynamic explanation.

  15. Study on eliminating fire dampers to maintain process confinement

    SciTech Connect

    Walling, R.C.; Patel, J.B.; Strunk, A.J.

    1991-01-01

    The DOE General Design Criteria for the Defense Waste Processing Facility (DWPF) at the Westinghouse Savannah River Site (WSRS) requires the NFPA National Fire Codes to be incorporated into the design and simultaneously maintain process confinement integrity to prevent the release of radioactivity. Although the NFPA Standard for the Installation of Air Conditioning and Ventilation Systems, NFPA 90, requires fire dampers (FD) in HVAC duct penetrations of two hour rated fire barriers, closure of fire dampers at DWPF may compromise the integrity of the process confinement system. This leads to the need for an overall risk assessment to determine the value of 39 fire dampers that are identified later in the study as capable of a confinement system upset.

  16. Study on eliminating fire dampers to maintain process confinement

    SciTech Connect

    Walling, R.C.; Patel, J.B.; Strunk, A.J.

    1991-12-31

    The DOE General Design Criteria for the Defense Waste Processing Facility (DWPF) at the Westinghouse Savannah River Site (WSRS) requires the NFPA National Fire Codes to be incorporated into the design and simultaneously maintain process confinement integrity to prevent the release of radioactivity. Although the NFPA Standard for the Installation of Air Conditioning and Ventilation Systems, NFPA 90, requires fire dampers (FD) in HVAC duct penetrations of two hour rated fire barriers, closure of fire dampers at DWPF may compromise the integrity of the process confinement system. This leads to the need for an overall risk assessment to determine the value of 39 fire dampers that are identified later in the study as capable of a confinement system upset.

  17. Confinement from spontaneous breaking of scale symmetry

    NASA Astrophysics Data System (ADS)

    Gaete, Patricio; Guendelman, Eduardo

    2006-09-01

    We show that one can obtain naturally the confinement of static charges from the spontaneous symmetry breaking of scale invariance in a gauge theory. At the classical level a confining force is obtained and at the quantum level, using a gauge invariant but path-dependent variables formalism, the Cornell confining potential is explicitly obtained. Our procedure answers completely to the requirements by 't Hooft for "perturbative confinement".

  18. Inertial-confinement-fusion targets

    SciTech Connect

    Hendricks, C.D.

    1981-11-16

    Inertial confinement fusion (ICF) targets are made as simple flat discs, as hollow shells or as complicated multilayer structures. Many techniques have been devised for producing the targets. Glass and metal shells are made by using drop and bubble techniques. Solid hydrogen shells are also produced by adapting old methods to the solution of modern problems. Some of these techniques, problems and solutions are discussed. In addition, the applications of many of the techniques to fabrication of ICF targets is presented.

  19. Ion beam inertial confinement target

    DOEpatents

    Bangerter, Roger O.; Meeker, Donald J.

    1985-01-01

    A target for implosion by ion beams composed of a spherical shell of frozen DT surrounded by a low-density, low-Z pusher shell seeded with high-Z material, and a high-density tamper shell. The target has various applications in the inertial confinement technology. For certain applications, if desired, a low-density absorber shell may be positioned intermediate the pusher and tamper shells.

  20. Confinement from constant field condensates

    NASA Astrophysics Data System (ADS)

    Gaete, Patricio; Guendelman, Eduardo; Spallucci, Euro

    2007-01-01

    For (2 + 1)- and (3 + 1)-dimensional reformulated SU (2) Yang-Mills theory, we compute the interaction potential within the framework of the gauge-invariant but path-dependent variables formalism. This reformulation is due to the presence of a constant gauge field condensate. Our results show that the interaction energy contains a linear term leading to the confinement of static probe charges. This result is equivalent to that of the massive Schwinger model.

  1. Nanoparticle Order through Entropic Confinement

    NASA Astrophysics Data System (ADS)

    Zhang, Ren; Lee, Bongjoon; Stafford, Christopher; Douglas, Jack; Bockstaller, Michael; Karim, Alamgir

    As has been addressed in colloidal science, visual order transitions can be achieved with entropy contributions alone. Herein, entropy-driven ordering of nanoparticle (NP) structures is generated where entropy increase and visual order are achieved simultaneously. We study an ``athermal'' NP-polymer blends where NPs are densely grafted with polymer brush of the same chemical composition as the polymer matrix. Visual order of the NPs is induced by geometrically confining the thin film blends with meso-scale topographic patterns. When the residual layer thickness of the patterned blend films approaches the nanoparticle dimension, exclusive segregation of NPs to less confining imprinted mesa region occurs. This preferential segregation of NPs, defined by partition coefficient K = 0, is attributed to purely entropic penalty, where K denotes the particle density ratio at highly confined residual layer to that at mesa region. We further demonstrate K is fully tunable and even invertible with increasing matrix chain dimension. The associated entropic free energy change (ΔF = - ln K) is calculated to explain NP segregation preference. Accordingly, variation of residual layer thickness and polymer matrix molecule size can both affect NP distribution among patterned thick and thin regions.

  2. Preparation of the high power laser system PETAL for experimental studies of inertial confinement fusion and high energy density states of matter

    NASA Astrophysics Data System (ADS)

    d'Humières, E.; Caron, J.; Perego, C.; Raffestin, D.; Dubois, J.-L.; Baggio, J.; Compant La Fontaine, A.; Hulin, S.; Ducret, J.-E.; Lubrano, F.; Gommé, J. C.; Gazave, J.; Ribolzi, J.; Feugeas, J.-L.; Nicolai, P.; Lefebvre, E.; Tikhonchuk, V. T.; Batani, D.

    2016-03-01

    The paper describes the preparation of the short-pulse high-energy laser PETAL that will be coupled to the French megajoule laser (LMJ) of CEA. The LMJ/PETAL facility will be opened to academic access for the international research community. In parallel diagnostics are being developed within the PETAL project and many physical problems are being addressed ranging from the study of the problems of radiation generation and activation issues to the problem of generation of large amplitude electromagnetic pulses.

  3. MARS PATHFINDER PYRO SYSTEMS SWITCHING ACTIVITY

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Mars Pathfinder lander is subjected to electrical and functional tests of its pyrotechic petal deployer system by Jet Propulsion Laboratory (JPL) engineers and technicians in KSC's Spacecraft Assembly and Encapsulation Facility (SAEF-2). When the lander touches down on the surface of Mars next year, the pyrotechnic system will deploy its three petals open like a flower and allow the Sojourner autonomous rover to explore the Martian surface. The Mars Pathfinder is scheduled for launch aboard a Delta II expendable launch vehicle on Dec. 2, the beginning of a 24-day launch period. JPL is managing the Mars Pathfinder project for NASA.

  4. PEGASUS: Designing a System for Supporting Group Activity

    ERIC Educational Resources Information Center

    Kyprianidou, Maria; Demetriadis, Stavros; Pombortsis, Andreas; Karatasios, George

    2009-01-01

    Purpose: The purpose of this paper is to present the design and first results of the integration of a web-based system person-centred group-activity support system (PEGASUS) in university instruction, as a means for advancing person-centred learning by supporting group activity. The PEGASUS is expected to help students and teachers in two distinct…

  5. Applying an Activity System to Online Collaborative Group Work Analysis

    ERIC Educational Resources Information Center

    Choi, Hyungshin; Kang, Myunghee

    2010-01-01

    This study determines whether an activity system provides a systematic framework to analyse collaborative group work. Using an activity system as a unit of analysis, the research examined learner behaviours, conflicting factors and facilitating factors while students engaged in collaborative work via asynchronous computer-mediated communication.…

  6. Quantum chromodynamics near the confinement limit

    SciTech Connect

    Quigg, C.

    1985-09-01

    These nine lectures deal at an elementary level with the strong interaction between quarks and its implications for the structure of hadrons. Quarkonium systems are studied as a means for measuring the interquark interaction. This is presumably (part of) the answer a solution to QCD must yield, if it is indeed the correct theory of the strong interactions. Some elements of QCD are reviewed, and metaphors for QCD as a confining theory are introduced. The 1/N expansion is summarized as a way of guessing the consequences of QCD for hadron physics. Lattice gauge theory is developed as a means for going beyond perturbation theory in the solution of QCD. The correspondence between statistical mechanics, quantum mechanics, and field theory is made, and simple spin systems are formulated on the lattice. The lattice analog of local gauge invariance is developed, and analytic methods for solving lattice gauge theory are considered. The strong-coupling expansion indicates the existence of a confining phase, and the renormalization group provides a means for recovering the consequences of continuum field theory. Finally, Monte Carlo simulations of lattice theories give evidence for the phase structure of gauge theories, yield an estimate for the string tension characterizing the interquark force, and provide an approximate description of the quarkonium potential in encouraging good agreement with what is known from experiment.

  7. Viscosity of confined inhomogeneous nonequilibrium fluids

    NASA Astrophysics Data System (ADS)

    Zhang, Junfang; Todd, B. D.; Travis, Karl P.

    2004-12-01

    We use the nonlocal linear hydrodynamic constitutive model, proposed by Evans and Morriss [Statistical Mechanics of Nonequilibrium Liquids (Academic, London, 1990)], for computing an effective spatially dependent shear viscosity of inhomogeneous nonequilibrium fluids. The model is applied to a simple atomic fluid undergoing planar Poiseuille flow in a confined channel of several atomic diameters width. We compare the spatially dependent viscosity with a local generalization of Newton's law of viscosity and the Navier-Stokes viscosity, both of which are known to suffer extreme inaccuracies for highly inhomogeneous systems. The nonlocal constitutive model calculates effective position dependent viscosities that are free from the notorious singularities experienced by applying the commonly used local constitutive model. It is simple, general, and has widespread applicability in nanofluidics where experimental measurement of position dependent transport coefficients is currently inaccessible. In principle the method can be used to predict approximate flow profiles of any arbitrary inhomogeneous system. We demonstrate this by predicting the flow profile for a simple fluid undergoing planar Couette flow in a confined channel of several atomic diameters width.

  8. Viscosity of confined inhomogeneous nonequilibrium fluids.

    PubMed

    Zhang, Junfang; Todd, B D; Travis, Karl P

    2004-12-01

    We use the nonlocal linear hydrodynamic constitutive model, proposed by Evans and Morriss [Statistical Mechanics of Nonequilibrium Liquids (Academic, London, 1990)], for computing an effective spatially dependent shear viscosity of inhomogeneous nonequilibrium fluids. The model is applied to a simple atomic fluid undergoing planar Poiseuille flow in a confined channel of several atomic diameters width. We compare the spatially dependent viscosity with a local generalization of Newton's law of viscosity and the Navier-Stokes viscosity, both of which are known to suffer extreme inaccuracies for highly inhomogeneous systems. The nonlocal constitutive model calculates effective position dependent viscosities that are free from the notorious singularities experienced by applying the commonly used local constitutive model. It is simple, general, and has widespread applicability in nanofluidics where experimental measurement of position dependent transport coefficients is currently inaccessible. In principle the method can be used to predict approximate flow profiles of any arbitrary inhomogeneous system. We demonstrate this by predicting the flow profile for a simple fluid undergoing planar Couette flow in a confined channel of several atomic diameters width. PMID:15549963

  9. Regimes of DNA confined in a nanochannel

    NASA Astrophysics Data System (ADS)

    Dai, Liang; Doyle, Patrick

    2014-03-01

    Scaling regimes for polymers confined to tubular channels are well established when the channel cross-sectional dimension is either very small (Odjik regime) or large (classic de Gennes regime) relative to the polymer Kuhn length. In the literature, there is no clear consensus regarding the intermediate region and if subregimes even exist to connect these two classic bounding regimes. The confluence of emerging single DNA mapping technologies and a resurged interest in the fundamental properties of confined polymers has led to extensive research in this area using DNA as a model system. Due to the DNA molecule's properties and limitations of nanofabrication, most experiments are performed in this intermediate regime with channel dimensions of a few Kuhn lengths. Here we use simulations and theory to reconcile conflicting theories and show that there are indeed extended de Gennes, partial alignment and hairpin regimes located between the two classic regimes. Simulations results for both chain extension and free energy support the existence of these regimes. This research was supported by the National Research Foundation Singapore through the Singapore MIT Alliance for Research and Technology's research program in BioSystems and Micromechanics, the National Science Foundation (CBET-1335938).

  10. Entry-Level Activities in System Consultation

    ERIC Educational Resources Information Center

    Hylander, Ingrid

    2014-01-01

    System-level consultation or organizational development in schools is an area in great need of theoretical models and definitions. The three articles in this special issue provide a unique learning opportunity not only for consultation across borders but also for consultation within the same nation. In my commentary, I limit my remarks to a few…

  11. Methodology for the systems engineering process. Volume 1: System functional activities

    NASA Technical Reports Server (NTRS)

    Nelson, J. H.

    1972-01-01

    Systems engineering is examined in terms of functional activities that are performed in the conduct of a system definition/design, and system development is described in a parametric analysis that combines functions, performance, and design variables. Emphasis is placed on identification of activities performed by design organizations, design specialty groups, as well as a central systems engineering organizational element. Identification of specific roles and responsibilities for doing functions, and monitoring and controlling activities within the system development operation are also emphasized.

  12. Thermodynamic instability of a confined gas.

    PubMed

    Posch, Harald A; Thirring, Walter

    2006-11-01

    The best possible cooling agent is a system with negative specific heat. If in thermal contact with a second system, any acquisition of energy due to a random fluctuation lowers its temperature, and the energy transfer in this direction is further enhanced. It continues until all the energy is extracted from the second system and their temperatures are at par. We exhibit these microcanonical features with a simple mechanical model of interacting classical gas particles in a specially confined domain and subjected to gravitation. As predicted, most of the gas particles are cooled and collect in the lowest part of the container, where the energy is carried away by a few remaining particles. PMID:17279873

  13. Dimensional reduction of duplex DNA under confinement to nanofluidic slits.

    PubMed

    Vargas-Lara, Fernando; Stavis, Samuel M; Strychalski, Elizabeth A; Nablo, Brian J; Geist, Jon; Starr, Francis W; Douglas, Jack F

    2015-11-14

    There has been much interest in the dimensional properties of double-stranded DNA (dsDNA) confined to nanoscale environments as a problem of fundamental importance in both biological and technological fields. This has led to a series of measurements by fluorescence microscopy of single dsDNA molecules under confinement to nanofluidic slits. Despite the efforts expended on such experiments and the corresponding theory and simulations of confined polymers, a consistent description of changes of the radius of gyration of dsDNA under strong confinement has not yet emerged. Here, we perform molecular dynamics (MD) simulations to identify relevant factors that might account for this inconsistency. Our simulations indicate a significant amplification of excluded volume interactions under confinement at the nanoscale due to the reduction of the effective dimensionality of the system. Thus, any factor influencing the excluded volume interaction of dsDNA, such as ionic strength, solution chemistry, and even fluorescent labels, can greatly influence the dsDNA size under strong confinement. These factors, which are normally less important in bulk solutions of dsDNA at moderate ionic strengths because of the relative weakness of the excluded volume interaction, must therefore be under tight control to achieve reproducible measurements of dsDNA under conditions of dimensional reduction. By simulating semi-flexible polymers over a range of parameter values relevant to the experimental systems and exploiting past theoretical treatments of the dimensional variation of swelling exponents and prefactors, we have developed a novel predictive relationship for the in-plane radius of gyration of long semi-flexible polymers under slit-like confinement. Importantly, these analytic expressions allow us to estimate the properties of dsDNA for the experimentally and biologically relevant range of contour lengths that is not currently accessible by state-of-the-art MD simulations. PMID

  14. Spherical microwave confinement and ball lightning

    NASA Astrophysics Data System (ADS)

    Robinson, William Richard

    This dissertation presents the results of research done on unconventional energy technologies from 1995 to 2009. The present civilization depends on an infrastructure that was constructed and is maintained almost entirely using concentrated fuels and ores, both of which will run out. Diffuse renewable energy sources rely on this same infrastructure, and hence face the same limitations. I first examined sonoluminescence directed toward fusion, but demonstrated theoretically that this is impossible. I next studied Low Energy Nuclear Reactions and developed methods for improving results, although these have not been implemented. In 2000, I began Spherical Microwave Confinement (SMC), which confines and heats plasma with microwaves in a spherical chamber. The reactor was designed and built to provide the data needed to investigate the possibility of achieving fusion conditions with microwave confinement. A second objective was to attempt to create ball lightning (BL). The reactor featured 20 magnetrons, which were driven by a capacitor bank and operated in a 0.2 s pulse mode at 2.45 GHz. These provided 20 kW to an icosahedral array of 20 antennas. Video of plasmas led to a redesign of the antennas to provide better coupling of the microwaves to the plasma. A second improvement was a grid at the base of the antennas, which provided corona electrons and an electric field to aid quick formation of plasmas. Although fusion conditions were never achieved and ball lightning not observed, experience gained from operating this basic, affordable system has been incorporated in a more sophisticated reactor design intended for future research. This would use magnets that were originally planned. The cusp geometry of the magnetic fields is suitable for electron cyclotron resonance in the same type of closed surface that in existing reactors has generated high-temperature plasmas. Should ball lightning be created, it could be a practical power source with nearly ideal

  15. A microscopic field theoretical approach for active systems

    NASA Astrophysics Data System (ADS)

    Alaimo, F.; Praetorius, S.; Voigt, A.

    2016-08-01

    We consider a microscopic modeling approach for active systems. The approach extends the phase field crystal (PFC) model and allows us to describe generic properties of active systems within a continuum model. The approach is validated by reproducing results obtained with corresponding agent-based and microscopic phase field models. We consider binary collisions, collective motion and vortex formation. For larger numbers of particles we analyze the coarsening process in active crystals and identify giant number fluctuation in a cluster formation process.

  16. Creating monodisperse polyacrylamide free-radically via thermal frontal polymerization in confined geometries

    NASA Astrophysics Data System (ADS)

    Datta, Preeta; Efimenko, Kirill; Genzer, Jan

    2014-03-01

    Bulk free radical polymerization reactions lead to highly polydisperse polymers (polydispersity index, PDI >> 1.5). In the past, researchers have shown that polymerization in porous microreactors can lower polydispersity (PDI ~1.5-1.7) by promoting gelation. We employ free-radical thermal frontal polymerization reaction of acrylamide (AAm) in DMSO in highly confined reactors (height <1mm) to produce high molecular weight (~300 kDa) PAAm of relatively low PDI (~1.2). In frontal polymerization systems, a localized reaction zone propagates in space along the direction of heat transfer, sustained by the interplay of heat diffusion and Arrhenius reaction kinetics. The directional heat transfer assists in maintaining the uniformity of the front temperature. While convection improves thermal transport, it causes inhomogeneity in the propagating front in horizontal reactors. In highly confined systems, convection is heavily suppressed, as manifested by the ``flattening'' of the reaction front and the absence of ``fingering''. Gelation lowers termination rate and increases the life time of the active reaction centers. Elimination of convection in confined geometries coupled with directional heat transfer and gelation results in polymers with high molecular weights and low PDIs.

  17. Plasma Confinement in the UCLA Electric Tokamak.

    NASA Astrophysics Data System (ADS)

    Taylor, Robert J.

    2001-10-01

    The main goal of the newly constructed large Electric Tokamak (R = 5 m, a = 1 m, BT < 0.25 T) is to access an omnigeneous, unity beta(S.C. Cowley, P.K. Kaw, R.S. Kelly, R.M. Kulsrud, Phys. fluids B 3 (1991) 2066.) plasma regime. The design goal was to achieve good confinement at low magnetic fields, consistent with the high beta goal. To keep the program cost down, we adopted the use of ICRF as the primary heating source. Consequently, antenna surfaces covering 1/2 of the surface of the tokamak has been prepared for heating and current drive. Very clean hydrogenic plasmas have been achieved with loop voltage below 0.7 volt and densities 3 times above the Murakami limit, n(0) > 8 x 10^12 cm-3 when there is no MHD activity. The electron temperature, derived from the plasma conductivity is > 250 eV with a central electron energy confinement time > 350 msec in ohmic conditions. The sawteeth period is 50 msec. Edge plasma rotation is induced by plasma biasing via electron injection in an analogous manner to that seen in CCT(R.J. Taylor, M.L. Brown, B.D. Fried, H. Grote, J.R. Liberati, G.J. Morales, P. Pribyl, D. Darrow, and M. Ono. Phys. Rev Lett. 63 2365 1989.) and the neoclassical bifurcation is close to that described by Shaing et al(K.C. Shaing and E.C. Crume, Phys. Rev. Lett. 63 2369 (1989).). In the ohmic phase the confinement tends to be MHD limited. The ICRF heating eliminates the MHD disturbances. Under second harmonic heating conditions, we observe an internal confinement peaking characterized by doubling of the core density and a corresponding increase in the central electron temperature. Charge exchange data, Doppler data in visible H-alpha light, and EC radiation all indicate that ICRF heating works much better than expected. The major effort is focused on increasing the power input and controlling the resulting equilibrium. This task appears to be easy since our current pulses are approaching the 3 second mark without RF heating or current drive. Our

  18. Motor Cortex Activity Organizes the Developing Rubrospinal System

    PubMed Central

    Williams, Preston T.J.A.

    2015-01-01

    The corticospinal and rubrospinal systems function in skilled movement control. A key question is how do these systems develop the capacity to coordinate their motor functions and, in turn, if the red nucleus/rubrospinal tract (RN/RST) compensates for developmental corticospinal injury? We used the cat to investigate whether the developing rubrospinal system is shaped by activity-dependent interactions with the developing corticospinal system. We unilaterally inactivated M1 by muscimol microinfusion between postnatal weeks 5 and 7 to examine activity-dependent interactions and whether the RN/RST compensates for corticospinal tract (CST) developmental motor impairments and CST misprojections after M1 inactivation. We examined the RN motor map and RST cervical projections at 7 weeks of age, while the corticospinal system was inactivated, and at 14 weeks, after activity returned. During M1 inactivation, the RN on the same side showed normal RST projections and reduced motor thresholds, suggestive of precocious development. By contrast, the RN on the untreated/active M1 side showed sparse RST projections and an immature motor map. After M1 activity returned later in adolescent cat development, RN on the active M1/CST side continued to show a substantial loss of spinal terminations and an impaired motor map. RN/RST on the inactivated side regressed to a smaller map and fewer axons. Our findings suggest that the developing rubrospinal system is under activity-dependent regulation by the corticospinal system for establishing mature RST connections and RN motor map. The lack of RS compensation on the non-inactivated side can be explained by development of ipsilateral misprojections from the active M1 that outcompete the RST. SIGNIFICANCE STATEMENT Skilled movements reflect the activity of multiple descending motor systems and their interactions with spinal motor circuits. Currently, there is little insight into whether motor systems interact during development to

  19. MARS PATHFINDER PYRO SYSTEMS SWITCHING ACTIVITY

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Mars Pathfinder lander is subjected to a electrical and functional tests of its pyrotechic petal deployer system by Jet Propulsion Laboratory (JPL) engineers and technicians in KSC's Spacecraft Assembly and Encapsulation Facility (SAEF-2). In the background is the Pathfinder cruise stage, which the lander will be mated to once its functional tests are complete. The lander will remain attached to this stage during its six-to-seven-month journey to Mars. When the lander touches down on the surface of Mars next year, the pyrotechnic system will deploy its three petals open like a flower and allow the Sojourner autonomous rover to explore the Martian surface. The Mars Pathfinder is scheduled for launch aboard a Delta II expendable launch vehicle on Dec. 2, the beginning of a 24-day launch period. JPL is managing the Mars Pathfinder project for NASA.

  20. MARS PATHFINDER PYRO SYSTEMS SWITCHING ACTIVITY

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Mars Pathfinder lander is subjected to a electrical test of its pyrotechnic system by Jet Propulsion Laboratory (JPL) engineers Lorraine Garcia (foreground) and Linda Robeck in KSC's Spacecraft Assembly and Encapsulation Facility (SAEF-2). A wheel of the Sojourner autonomous rover, which is attached to one of the lander's petals, can be seen behind the lander. When the lander touches down on the surface of Mars next year, the pyrotechnic system will deploy its three petals open like a flower and allow the rover to explore the Martian surface. The Mars Pathfinder is scheduled for launch aboard a Delta II expendable launch vehicle on Dec. 2, the beginning of a 24-day launch period. JPL is managing the Mars Pathfinder project for NASA.