Science.gov

Sample records for accelerator complex consists

  1. The Tandem-ALPI-PIAVE accelerator complex of LNL

    SciTech Connect

    Ur, C. A.

    2013-07-18

    Heavy ion beams are delivered at the Laboratori Nazionali di Legnaro by the accelerator complex Tandem-ALPI-PIAVE. The Tandem XTU is a Van de Graaff accelerator normally operated at terminal voltages of up to about 15 MV. The Tandem accelerator can be operated in stand-alone mode or as an injector for the linac booster ALPI. The linear accelerator ALPI is built of superconducting resonant cavities and consists of a low-beta branch, particularly important for the acceleration of the heavier mass ions, a medium-beta branch, and a high-beta branch. ALPI can be operated also with the PIAVE injector that consists of a superconducting linac and an ECR source. The PIAVE source was mainly used for the acceleration of intense noble gas beams but most recently also a first metallic beam was delivered to the users. The accelerator complex delivers beams of ions from protons to gold in three experimental areas on 11 different beam lines. A rich scientific activity is ongoing at the Tandem-ALPI-PIAVE accelerator complex, beam time being shared between nuclear physics research and applied and interdisciplinary physics research. An overview of the present status and perspectives of the Tandem-ALPI-PIAVE complex and its physics program is given in the present paper.

  2. VIEW OF COMPLEX OF BUILDINGS CONSISTING OF A THREESTORY REINFORCED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF COMPLEX OF BUILDINGS CONSISTING OF A THREE-STORY REINFORCED CONCRETE FACTORY WITH A SMALLER ONE-STORY LOADING DOCK AND ANOTHER ONE-STORY BRICK AND STEEL BUILDING ON THE EAST FACADE. THE THREE-STORY BUILDING HAS VERTICAL METAL PANELING ON THE UPPER STORY. THE ENTIRE COMPLEX IS PAINTED PINK WITH MUCH DAMAGE TO THE EXTERIOR OF THE BUILDING ON THE SOUTH SIDE - American Can Company, 1400 Trombly Avenue, Detroit, MI

  3. VIEW OF COMPLEX OF BUILDINGS CONSISTING OF A THREESTORY REINFORCED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF COMPLEX OF BUILDINGS CONSISTING OF A THREE-STORY REINFORCED CONCRETE FACTORY WITH A SMALLER ONE-STORY LOADING DOCK AND ANOTHER ONE-STORY BRICK AND STEEL BUILDING ON THE EAST FACADE. THE THREE-STORY BUILDING HAS VERTICAL METAL PANELING ON THE UPPER STORY. THE ENTIRE COMPLEX IS PAINTED PINK WITH MUCH DAMAGE TO THE EXTERIOR OF THE BUILDING ON THE SOUTH SIDE. (Duplicate color view of HAER MI-340-1) - American Can Company, 1400 Trombly Avenue, Detroit, MI

  4. Road Map for Studies to Produce Consistent and High Performance SRF Accelerator Structures

    SciTech Connect

    Ganapati Rao Myneni; John F. O’Hanlon

    2007-06-20

    Superconducting Radio Frequency (SRF) accelerator structures made from high purity niobium are becoming the technological choice for a large number of future accelerators and energy recovery LINAC’s (ERL). Most of the presently planned accelerators and ERL requirements will be met with some effort by the current SRF technology where accelerating gradients of about 20 MV/m can be produced on a routine basis with an acceptable yield. However, the XFEL at DESY and the planned ILC require acceleration gradients more than 28 MV/m and 35 MV/m respectively. At the recent ILC meeting at Snowmass (2005) concern was expressed regarding the wide spread in the achieved accelerator gradients and the relatively low yields. For obtaining accelerating gradients of 35 MV/m in SRF accelerator structures consistently, a deeper understanding of the causes for the spread has to be gained and advances have to be made in many scientific and high technology fields, including materials, surface and vacuum sciences, application of reliable processes and procedures, which provide contamination –free surfaces and avoid recontamination and cryogenics related technologies. In this contribution a road map for studies needed to produce consistent and high performance SRF accelerator structures from the needed materials development to clean and non-recontaminating processes and procedures will be presented.

  5. Synchronization in node of complex networks consist of complex chaotic system

    SciTech Connect

    Wei, Qiang; Xie, Cheng-jun; Liu, Hong-jun; Li, Yan-hui

    2014-07-15

    A new synchronization method is investigated for node of complex networks consists of complex chaotic system. When complex networks realize synchronization, different component of complex state variable synchronize up to different scaling complex function by a designed complex feedback controller. This paper change synchronization scaling function from real field to complex field for synchronization in node of complex networks with complex chaotic system. Synchronization in constant delay and time-varying coupling delay complex networks are investigated, respectively. Numerical simulations are provided to show the effectiveness of the proposed method.

  6. Wakes in complex plasmas: A self-consistent kinetic theory

    NASA Astrophysics Data System (ADS)

    Kompaneets, Roman; Morfill, Gregor E.; Ivlev, Alexei V.

    2016-06-01

    In ground-based experiments with complex (dusty) plasmas, charged microparticles are levitated against gravity by an electric field, which also drives ion flow in the parent gas. Existing analytical approaches to describe the electrostatic interaction between microparticles in such conditions generally ignore the field and ion-neutral collisions, assuming free ion flow with a certain approximation for the ion velocity distribution function (usually a shifted Maxwellian). We provide a comprehensive analysis of our previously proposed self-consistent kinetic theory including the field, ion-neutral collisions, and the corresponding ion velocity distribution. We focus on various limiting cases and demonstrate how the interplay of these factors results in different forms of the shielding potential.

  7. Wakes in complex plasmas: A self-consistent kinetic theory.

    PubMed

    Kompaneets, Roman; Morfill, Gregor E; Ivlev, Alexei V

    2016-06-01

    In ground-based experiments with complex (dusty) plasmas, charged microparticles are levitated against gravity by an electric field, which also drives ion flow in the parent gas. Existing analytical approaches to describe the electrostatic interaction between microparticles in such conditions generally ignore the field and ion-neutral collisions, assuming free ion flow with a certain approximation for the ion velocity distribution function (usually a shifted Maxwellian). We provide a comprehensive analysis of our previously proposed self-consistent kinetic theory including the field, ion-neutral collisions, and the corresponding ion velocity distribution. We focus on various limiting cases and demonstrate how the interplay of these factors results in different forms of the shielding potential. PMID:27415371

  8. A Self-Consistent Beam Loaded Travelling Wave Accelerator Model for use in TRACE-3D

    NASA Astrophysics Data System (ADS)

    Lampel, M. C.

    1997-05-01

    An optics model of a constant gradient traveling wave (CGTW) accelerator structure has been implemented for TRACE-3D. TRACE-3D is an envelope code including space charge that is used to model bunched beams in magnetic transport systems and radio frequency (rf) accelerators when the effects of beam current might be significant. The new matrix model has been developed to allow incorporation of particle beam loading (current) effects on the accelerator gradient and the accelerator structure's beam focusing properties in a self-consistent manner. The beam loaded electric field for a CGTW accelerator structure is constant for only a particular design current (e.g., 0 current), otherwise it can be written as a function of accelerator attenuation and axial position along the structure. The variation of the electric field through the structure has been taken into account in the new model. CGTW structures differ substantially in focusing properties and beam loading properties from standing wave structures. Examples will be presented using the new TW model, propagating electron beams with different currents through the Stanford Linear Accelerator Center's 3 m structure. The results will be compared to the zero current TW structure model in TRANSPORT and the Tank model (a standing wave structure model) in TRACE-3D. A computer demonstration of the code with the new element will also be presented.

  9. Modeling Extreme Solar Energetic Particle Acceleration with Self-Consistent Wave Generation

    NASA Astrophysics Data System (ADS)

    Arthur, A. D.; le Roux, J. A.

    2015-12-01

    Observations of extreme solar energetic particle (SEP) events associated with coronal mass ejection driven shocks have detected particle energies up to a few GeV at 1 AU within the first ~10 minutes to 1 hour of shock acceleration. Whether or not acceleration by a single shock is sufficient in these events or if some combination of multiple shocks or solar flares is required is currently not well understood. Furthermore, the observed onset times of the extreme SEP events place the shock in the corona when the particles escape upstream. We have updated our focused transport theory model that has successfully been applied to the termination shock and traveling interplanetary shocks in the past to investigate extreme SEP acceleration in the solar corona. This model solves the time-dependent Focused Transport Equation including particle preheating due to the cross shock electric field and the divergence, adiabatic compression, and acceleration of the solar wind flow. Diffusive shock acceleration of SEPs is included via the first-order Fermi mechanism for parallel shocks. To investigate the effects of the solar corona on the acceleration of SEPs, we have included an empirical model for the plasma number density, temperature, and velocity. The shock acceleration process becomes highly time-dependent due to the rapid variation of these coronal properties with heliocentric distance. Additionally, particle interaction with MHD wave turbulence is modeled in terms of gyroresonant interactions with parallel propagating Alfven waves. However, previous modeling efforts suggest that the background amplitude of the solar wind turbulence is not sufficient to accelerate SEPs to extreme energies over the short time scales observed. To account for this, we have included the transport and self-consistent amplification of MHD waves by the SEPs through wave-particle gyroresonance. We will present the results of this extended model for a single fast quasi-parallel CME driven shock in the

  10. Progress Towards Doubling the Beam Power at Fermilab's Accelerator Complex

    SciTech Connect

    Kourbanis, Ioanis

    2014-07-01

    After a 16 month shutdown to reconfigure the Fermilab Accelerators for high power operations, the Fermilab Accelerator Complex is again providing beams for numerous Physics Experiments. By using the Recycler to slip stack protons while the Main Injector is ramping, the beam power at 120 GeV can reach 700 KW, a factor of 2 increase. The progress towards doubling the Fermilab's Accelerator complex beam power will be presented.

  11. Particle acceleration in the dynamic magnetotail: Orbits in self-consistent three-dimensional MHD fields

    NASA Technical Reports Server (NTRS)

    Birn, Joachim; Hesse, Michael

    1994-01-01

    The acceleration of protons in a dynamically evolving magnetotail is investigated by tracing particles in the fields obtained from a three-dimensional resistive magnetohydrodynamic (MHD) simulation. The MHD simulation, representing plasmoid formation and ejection through a near-Earth reconnection process, leads to cross-tail electric fields of up to approximately 4 mV/m with integrated voltages across the tail of up to approximately 200 kV. Energization of particles takes place over a wide range along the tail, due to the large spatial extent of the increased electric field together with the finite cross-tail extent of the electric field region. Such accelerated particles appear earthward of the neutral line over a significant portion of the closed field line region inside of the separatrix, not just in the vicinity of the separatrix. Two different acceleration processes are identified: a 'quasi-potential' acceleration, due to particle motion in the direction of the cross-tail electric field, and a 'quasi-betatron' effect, which consists of multiple energy gains from repeated crossings of the acceleration region, mostly on Speiser-type orbits, in the spatially varying induced electric field. The major source region for accelerated particles in the hundreds of keV range is the central plasma sheet at the dawn flank outside the reconnection site. Since this source plasma is already hot and dense, its moderate energization by a factor of approximately 2 may be sufficient to explain the observed increases in the energetic particle fluxes. Particles from the tail are the source of beams at the plasma sheet/lobe boundary. The temporal increase in the energetic particle fluxes, estimated from the increase in energy gain, occurs on a fast timescale of a few minutes, coincident with a strong increase in B(sub z), despite the fact that the inner boundary ('injection boundary') of the distribution of energized particles is fairly smooth.

  12. Accelerating self-consistent field convergence with the augmented Roothaan–Hall energy function

    PubMed Central

    Hu, Xiangqian; Yang, Weitao

    2010-01-01

    Based on Pulay’s direct inversion iterative subspace (DIIS) approach, we present a method to accelerate self-consistent field (SCF) convergence. In this method, the quadratic augmented Roothaan–Hall (ARH) energy function, proposed recently by Høst and co-workers [J. Chem. Phys. 129, 124106 (2008)], is used as the object of minimization for obtaining the linear coefficients of Fock matrices within DIIS. This differs from the traditional DIIS of Pulay, which uses an object function derived from the commutator of the density and Fock matrices. Our results show that the present algorithm, abbreviated ADIIS, is more robust and efficient than the energy-DIIS (EDIIS) approach. In particular, several examples demonstrate that the combination of ADIIS and DIIS (“ADIIS+DIIS”) is highly reliable and efficient in accelerating SCF convergence. PMID:20136307

  13. A class of transient acceleration models consistent with Big Bang cosmology

    NASA Astrophysics Data System (ADS)

    Zu, Tian-Long; Chen, Jie-Wen; Zhang, Yang

    2014-02-01

    Is it possible that the current cosmic accelerating expansion will turn into a decelerating one? Can this transition be realized by some viable theoretical model that is consistent with the standard Big Bang cosmology? We study a class of phenomenological models with a transient acceleration, based on a dynamical dark energy with a very general form of equation of state pde = βρde - βρdem. It mimics the cosmological constant ρde → const for a small scale factor a, and behaves as a barotropic gas with ρde → a-3(α+1) with α >= 0 for large a. The cosmic evolution of four models in the class has been examined in detail, and all yield a smooth transient acceleration. Depending on the specific model, the future universe may be dominated by either dark energy or by matter. In two models, the dynamical dark energy can be explicitly realized by a scalar field with an analytical potential V(φ). Moreover, a statistical analysis shows that the models can be as robust as ΛCDM in confronting the observational data of Type Ia supernovae, cosmic microwave background (CMB) and baryon acoustic oscillation. As improvements over previous studies, our models overcome the problem of over-abundance of dark energy during early eras, and satisfy the constraints on dark energy from WMAP observations of CMB.

  14. High luminosity operation of the Fermilab accelerator complex

    SciTech Connect

    Shekhar Mishra

    2003-07-15

    Run-II at Fermilab is progressing steadily. In the Run-II scheme, 36 antiproton bunches collide with 36 proton bunches at the CDF and D0 interaction regions in the Tevatron at 980 GeV per beam. The current status and performance of the Fermilab Accelerator complex is reviewed. The plan for Run-II, accelerator upgrades and integration of the Recycler in the accelerator chain will be presented.

  15. A consistent approach for the treatment of Fermi acceleration in time-dependent billiards.

    PubMed

    Karlis, A K; Diakonos, F K; Constantoudis, V

    2012-06-01

    The standard description of Fermi acceleration, developing in a class of time-dependent billiards, is given in terms of a diffusion process taking place in momentum space. Within this framework, the evolution of the probability density function (PDF) of the magnitude of particle velocities as a function of the number of collisions n is determined by the Fokker-Planck equation (FPE). In the literature, the FPE is constructed by identifying the transport coefficients with the ensemble averages of the change of the magnitude of particle velocity and its square in the course of one collision. Although this treatment leads to the correct solution after a sufficiently large number of collisions have been reached, the transient part of the evolution of the PDF is not described. Moreover, in the case of the Fermi-Ulam model (FUM), if a standard simplification is employed, the solution of the FPE is even inconsistent with the values of the transport coefficients used for its derivation. The goal of our work is to provide a self-consistent methodology for the treatment of Fermi acceleration in time-dependent billiards. The proposed approach obviates any assumptions for the continuity of the random process and the existence of the limits formally defining the transport coefficients of the FPE. Specifically, we suggest, instead of the calculation of ensemble averages, the derivation of the one-step transition probability function and the use of the Chapman-Kolmogorov forward equation. This approach is generic and can be applied to any time-dependent billiard for the treatment of Fermi-acceleration. As a first step, we apply this methodology to the FUM, being the archetype of time-dependent billiards to exhibit Fermi acceleration. PMID:22757579

  16. A consistent approach for the treatment of Fermi acceleration in time-dependent billiards

    NASA Astrophysics Data System (ADS)

    Karlis, A. K.; Diakonos, F. K.; Constantoudis, V.

    2012-06-01

    The standard description of Fermi acceleration, developing in a class of time-dependent billiards, is given in terms of a diffusion process taking place in momentum space. Within this framework, the evolution of the probability density function (PDF) of the magnitude of particle velocities as a function of the number of collisions n is determined by the Fokker-Planck equation (FPE). In the literature, the FPE is constructed by identifying the transport coefficients with the ensemble averages of the change of the magnitude of particle velocity and its square in the course of one collision. Although this treatment leads to the correct solution after a sufficiently large number of collisions have been reached, the transient part of the evolution of the PDF is not described. Moreover, in the case of the Fermi-Ulam model (FUM), if a standard simplification is employed, the solution of the FPE is even inconsistent with the values of the transport coefficients used for its derivation. The goal of our work is to provide a self-consistent methodology for the treatment of Fermi acceleration in time-dependent billiards. The proposed approach obviates any assumptions for the continuity of the random process and the existence of the limits formally defining the transport coefficients of the FPE. Specifically, we suggest, instead of the calculation of ensemble averages, the derivation of the one-step transition probability function and the use of the Chapman-Kolmogorov forward equation. This approach is generic and can be applied to any time-dependent billiard for the treatment of Fermi-acceleration. As a first step, we apply this methodology to the FUM, being the archetype of time-dependent billiards to exhibit Fermi acceleration.

  17. Quench detector for superconducting elements of the NICA accelerator complex

    NASA Astrophysics Data System (ADS)

    Ivanov, E. V.; Svetov, L. A.; Smirnova, Z. I.

    2014-07-01

    A universal quench detector is designed for new superconducting accelerators of the NICA accelerator complex under construction at JINR. The presence of a two-channel digital input permits the detector to be used both for comparing voltage across two nearest magnets by a bridge scheme and for separating a resistive constituent of the voltage across a controlled element.

  18. IMPROVING CONSISTENCY OF PERFORMANCE ASSESSMENTS IN THE DOE COMPLEX

    SciTech Connect

    Seitz, R; Elmer Wilhite, E

    2009-01-20

    The low-level waste (LLW) performance assessment (PA) process has been traditionally focused on disposal facilities at a few United States Department of Energy (USDOE) sites and commercial disposal facilities. In recent years, there has been a dramatic increase in the scope of the use of PA-like modeling approaches, involving multiple activities, facilities, contractors and regulators. The scope now includes, for example: (1) National Environmental Policy Act (NEPA) assessments, (2) CERCLA disposal cells, (3) Waste Determinations and High-Level Waste (HLW) Closure activities, (4) Potential on-site disposal of Transuranic (TRU) waste, and (5) In-situ decommissioning (including potential use of existing facilities for disposal). The dramatic increase in the variety of activities requiring more detailed modeling has resulted in a similar increase in the potential for inconsistency in approaches both at a site and complexwide scale. This paper includes a summary of USDOE Environmental Management (EM) sponsored initiatives and activities for improved consistency. New initiatives entitled the Performance Assessment Community of Practice and Performance Assessment Assistance Team are also introduced.

  19. Overcoming complexities for consistent, continental-scale flood mapping

    NASA Astrophysics Data System (ADS)

    Smith, Helen; Zaidman, Maxine; Davison, Charlotte

    2013-04-01

    The EU Floods Directive requires all member states to produce flood hazard maps by 2013. Although flood mapping practices are well developed in Europe, there are huge variations in the scale and resolution of the maps between individual countries. Since extreme flood events are rarely confined to a single country, this is problematic, particularly for the re/insurance industry whose exposures often extend beyond country boundaries. Here, we discuss the challenges of large-scale hydrological and hydraulic modelling, using our experience of developing a 12-country model and set of maps, to illustrate how consistent, high-resolution river flood maps across Europe can be produced. The main challenges addressed include: data acquisition; manipulating the vast quantities of high-resolution data; and computational resources. Our starting point was to develop robust flood-frequency models that are suitable for estimating peak flows for a range of design flood return periods. We used the index flood approach, based on a statistical analysis of historic river flow data pooled on the basis of catchment characteristics. Historical flow data were therefore sourced for each country and collated into a large pan-European database. After a lengthy validation these data were collated into 21 separate analysis zones or regions, grouping smaller river basins according to their physical and climatic characteristics. The very large continental scale basins were each modelled separately on account of their size (e.g. Danube, Elbe, Drava and Rhine). Our methodology allows the design flood hydrograph to be predicted at any point on the river network for a range of return periods. Using JFlow+, JBA's proprietary 2D hydraulic hydrodynamic model, the calculated out-of-bank flows for all watercourses with an upstream drainage area exceeding 50km2 were routed across two different Digital Terrain Models in order to map the extent and depth of floodplain inundation. This generated modelling for

  20. Development of an artificial climatic complex accelerated corrosion tester and investigation of complex accelerated corrosion test methods

    SciTech Connect

    Li, J.; Li, M.; Sun, Z. )

    1999-05-01

    During recent decades, accelerated corrosion test equipment and methods simulating atmospheric corrosion have been developed to incorporate the many factors involved in complex accelerated corrosion. A new accelerated corrosion tester was developed to simulate various kinds of atmospheric corrosion environments. The equipment can be used to simulate various types of atmospheric corrosion environments with up to eight factors and can be used to carry out 18 kinds of standard corrosion and environmental tasks.

  1. Electron acceleration in combined intense laser fields and self-consistent quasistatic fields in plasma

    SciTech Connect

    Qiao Bin; He, X.T.; Zhu Shaoping; Zheng, C.Y.

    2005-08-15

    The acceleration of plasma electron in intense laser-plasma interaction is investigated analytically and numerically, where the conjunct effect of laser fields and self-consistent spontaneous fields (including quasistatic electric field E{sub s}{sup l}, azimuthal quasistatic magnetic field B{sub s{theta}} and the axial one B{sub sz}) is completely considered for the first time. An analytical relativistic electron fluid model using test-particle method has been developed to give an explicit analysis about the effects of each quasistatic fields. The ponderomotive accelerating and scattering effects on electrons are partly offset by E{sub s}{sup l}, furthermore, B{sub s{theta}} pinches and B{sub sz} collimates electrons along the laser axis. The dependences of energy gain and scattering angle of electron on its initial radial position, plasma density, and laser intensity are, respectively, studied. The qualities of the relativistic electron beam (REB), such as energy spread, beam divergence, and emitting (scattering) angle, generated by both circularly polarized (CP) and linearly polarized (LP) lasers are studied. Results show CP laser is of clear advantage comparing to LP laser for it can generate a better REB in collimation and stabilization.

  2. Software Accelerates Computing Time for Complex Math

    NASA Technical Reports Server (NTRS)

    2014-01-01

    Ames Research Center awarded Newark, Delaware-based EM Photonics Inc. SBIR funding to utilize graphic processing unit (GPU) technology- traditionally used for computer video games-to develop high-computing software called CULA. The software gives users the ability to run complex algorithms on personal computers with greater speed. As a result of the NASA collaboration, the number of employees at the company has increased 10 percent.

  3. Acceleration in Perpendicular Relativistic Shocks for Plasmas Consisting of Leptons and Hadrons

    NASA Astrophysics Data System (ADS)

    Stockem, A.; Fiúza, F.; Fonseca, R. A.; Silva, L. O.

    2012-08-01

    We investigate the acceleration of light particles in perpendicular shocks for plasmas consisting of a mixture of leptonic and hadronic particles. Starting from the full set of conservation equations for the mixed plasma constituents, we generalize the magnetohydrodynamical jump conditions for a multi-component plasma, including information about the specific adiabatic constants for the different species. The impact of deviations from the standard model of an ideal gas is compared in theory and particle-in-cell simulations, showing that the standard MHD model is a good approximation. The simulations of shocks in electron-positron-ion plasmas are for the first time multi-dimensional, transverse effects are small in this configuration, and one-dimensional (1D) simulations are a good representation if the initial magnetization is chosen high. 1D runs with a mass ratio of 1836 are performed, which identify the Larmor frequency ω ci as the dominant frequency that determines the shock physics in mixed component plasmas. The maximum energy in the non-thermal tail of the particle spectra evolves in time according to a power law vpropt α with α in the range 1/3 < α < 1, depending on the initial parameters. A connection is made with transport theoretical models by Drury and Gargaté & Spitkovsky, which predict an acceleration time vpropγ and the theory for small wavelength scattering by Kirk & Reville, which predicts a behavior rather as vpropγ2. Furthermore, we compare different magnetic field orientations with B 0 inside and out of the plane, observing qualitatively different particle spectra than in pure electron-ion shocks.

  4. ACCELERATION IN PERPENDICULAR RELATIVISTIC SHOCKS FOR PLASMAS CONSISTING OF LEPTONS AND HADRONS

    SciTech Connect

    Stockem, A.; Fiuza, F.; Fonseca, R. A.; Silva, L. O.

    2012-08-10

    We investigate the acceleration of light particles in perpendicular shocks for plasmas consisting of a mixture of leptonic and hadronic particles. Starting from the full set of conservation equations for the mixed plasma constituents, we generalize the magnetohydrodynamical jump conditions for a multi-component plasma, including information about the specific adiabatic constants for the different species. The impact of deviations from the standard model of an ideal gas is compared in theory and particle-in-cell simulations, showing that the standard MHD model is a good approximation. The simulations of shocks in electron-positron-ion plasmas are for the first time multi-dimensional, transverse effects are small in this configuration, and one-dimensional (1D) simulations are a good representation if the initial magnetization is chosen high. 1D runs with a mass ratio of 1836 are performed, which identify the Larmor frequency {omega}{sub ci} as the dominant frequency that determines the shock physics in mixed component plasmas. The maximum energy in the non-thermal tail of the particle spectra evolves in time according to a power law {proportional_to}t{sup {alpha}} with {alpha} in the range 1/3 < {alpha} < 1, depending on the initial parameters. A connection is made with transport theoretical models by Drury and Gargate and Spitkovsky, which predict an acceleration time {proportional_to}{gamma} and the theory for small wavelength scattering by Kirk and Reville, which predicts a behavior rather as {proportional_to}{gamma}{sup 2}. Furthermore, we compare different magnetic field orientations with B{sub 0} inside and out of the plane, observing qualitatively different particle spectra than in pure electron-ion shocks.

  5. Classification Consistency and Accuracy for Complex Assessments under the Compound Multinomial Model

    ERIC Educational Resources Information Center

    Lee, Won-Chan; Brennan, Robert L.; Wan, Lei

    2009-01-01

    For a test that consists of dichotomously scored items, several approaches have been reported in the literature for estimating classification consistency and accuracy indices based on a single administration of a test. Classification consistency and accuracy have not been studied much, however, for "complex" assessments--for example, those that…

  6. The BNL AGS accelerator complex status and future plans

    SciTech Connect

    Tanaka, Mitsuyoshi

    1997-05-01

    This paper describes the present performance and capability of the BNL AGS accelerator complex and possible future intensity upgrade plans. In 1995, the AGS reached its design upgrade goal of 6.0 x 10(exp 13) ppp with the Booster. The AGS with a new fast extracted beam (FEB) system is able to perform single bunch multiple extraction at 30 Hz per AGS cycle for the g-2 experiment and for RHIC injection.

  7. The BNL AGS accelerator complex status and future plans

    SciTech Connect

    Tanaka, Mitsuyoshi

    1997-05-20

    This paper describes the present performance and capability of the BNL AGS accelerator complex and possible future intensity upgrade plans. In 1995, the AGS reached its design upgrade goal of 6.0{center_dot}10{sup 13} ppp with the Booster. The AGS with a new fast extracted beam (FEB) system is able to perform single bunch multiple extraction at 30 Hz per AGS cycle for the g-2 experiment and for RHIC injection.

  8. The BNL AGS accelerator complex status and future plans

    SciTech Connect

    Tanaka, M.

    1997-05-01

    This paper describes the present performance and capability of the BNL AGS accelerator complex and possible future intensity upgrade plans. In 1995, the AGS reached its design upgrade goal of 6.0{center_dot}10{sup 13}ppp with the Booster. The AGS with a new fast extracted beam (FEB) system is able to perform single bunch multiple extraction at 30 Hz per AGS cycle for the g-2 experiment and for RHIC injection. {copyright} {ital 1997 American Institute of Physics.}

  9. Accelerating procelain formation by incorporating a complex additive

    SciTech Connect

    Maslennikova, G.N.; Dubovitskii, S.A.; Moroz, I.K.

    1986-05-01

    The authors studied the influence of a complex additive consisting of oxides of calcium, zinc, and magnesium on the formaton of porcelain. In order to achieve a more uniform distribution of the complex additive in the porcelain body it was incorporated in the form of water soluble salts-nitrates, which ensured comparability of results and excluded the effect of the different types of anions. The study of the main parameters of sintering (porosity, shrinkage, and mechanical strength) for the test bodies showed that they sinter at lower temperatures and attain zero porosity, maximum shrinkage, and mechanical strength. The most typical bodies indentified in this way were investigated by methods of complex differential thermal analysis and x-ray diffraction. Thus, the introduction of complex additives consisting of calcium, zinc, and magnesium oxides contributes to the earlier formation of porcelain. With the reduction of firing temperatures by 100/sup 0/C the authors observe an improvement in the basic properties of porcelain.

  10. International Scoping Study of a Future Accelerator NeutrinoComplex

    SciTech Connect

    Zisman, Michael S.

    2006-06-21

    The International Scoping Study (ISS), launched at NuFact05 to evaluate the physics case for a future neutrino facility, along with options for the accelerator complex and detectors, is laying the foundations for a subsequent conceptual-design study. It is hosted by Rutherford Appleton Laboratory (RAL) and organized by the international community, with participants from Europe, Japan, and the U.S. Here we cover the work of the Accelerator Working Group. For the 4-MW proton driver, linacs, synchrotrons, and Fixed-Field Alternating Gradient (FFAG) rings are considered. For targets, issues of both liquid-metal and solid materials are examined. For beam conditioning, (phase rotation, bunching, and ionization cooling), we evaluate schemes both with and without cooling, the latter based on scaling-FFAG rings. For acceleration, we examine scaling FFAGs and hybrid systems comprising linacs, dogbone RLAs, and non-scaling FFAGs. For the decay ring, we consider racetrack and triangular shapes, the latter capable of simultaneously illuminating two different detectors at different long baselines. Comparisons are made between various technical approaches to identify optimum design choices.

  11. Elliptic Preconditioner for Accelerating the Self-Consistent Field Iteration in Kohn--Sham Density Functional Theory

    SciTech Connect

    Lin, Lin; Yang, Chao

    2013-10-28

    We discuss techniques for accelerating the self consistent field (SCF) iteration for solving the Kohn-Sham equations. These techniques are all based on constructing approximations to the inverse of the Jacobian associated with a fixed point map satisfied by the total potential. They can be viewed as preconditioners for a fixed point iteration. We point out different requirements for constructing preconditioners for insulating and metallic systems respectively, and discuss how to construct preconditioners to keep the convergence rate of the fixed point iteration independent of the size of the atomistic system. We propose a new preconditioner that can treat insulating and metallic system in a unified way. The new preconditioner, which we call an elliptic preconditioner, is constructed by solving an elliptic partial differential equation. The elliptic preconditioner is shown to be more effective in accelerating the convergence of a fixed point iteration than the existing approaches for large inhomogeneous systems at low temperature.

  12. Classification Consistency and Accuracy for Complex Assessments Using Item Response Theory

    ERIC Educational Resources Information Center

    Lee, Won-Chan

    2010-01-01

    In this article, procedures are described for estimating single-administration classification consistency and accuracy indices for complex assessments using item response theory (IRT). This IRT approach was applied to real test data comprising dichotomous and polytomous items. Several different IRT model combinations were considered. Comparisons…

  13. Hydrogen pellet acceleration with a two-stage system consisting of a gas gun and a fuseless electromagnetic railgun

    SciTech Connect

    Honig, J.; Kim, K.; Wedge, S.W.

    1986-05-01

    Hydrogen pellets are successfully accelerated for the first time using a two-stage system consisting of a pneumatic gun and an electromagnetic railgun. The pneumatic gun preaccelerator forms cylindrical hydrogen ice pellets (1.6-mm diam x 2.15-mm long) and accelerates them with high-pressure helium gas to velocities in excess of 500 m/s. The booster accelerator, which is a fuseless, circular-bore electromagnetic railgun, derives its propulsive force from a plasma arc armature. The plasma arc armature is formed by electrically breaking down the propellant gas which follows the pellet from the gas gun into the railgun. The diagnostics are for the monitoring of the main capacitor bank and rail currents, for the pellet detection and velocity measurements at the breech and muzzle ends of the railgun, for the recording of the plasma-arc-armature movement inside the railgun bore, and for the photographing of the hydrogen pellet exiting the railgun. Using the system, which is a 60-cm long proof-of-principle machine for refueling magnetic fusion devices, hyrogen pellet velocities exceeding 1 km/s have been achieved for pellets exiting the gas gun at velocities of approx.500 m/s.

  14. Using complex networks to quantify consistency in the use of words

    NASA Astrophysics Data System (ADS)

    Amancio, D. R.; Oliveira, O. N., Jr.; Costa, L. da F.

    2012-01-01

    In this paper we have quantified the consistency of word usage in written texts represented by complex networks, where words were taken as nodes, by measuring the degree of preservation of the node neighborhood. Words were considered highly consistent if the authors used them with the same neighborhood. When ranked according to the consistency of use, the words obeyed a log-normal distribution, in contrast to Zipf's law that applies to the frequency of use. Consistency correlated positively with the familiarity and frequency of use, and negatively with ambiguity and age of acquisition. An inspection of some highly consistent words confirmed that they are used in very limited semantic contexts. A comparison of consistency indices for eight authors indicated that these indices may be employed for author recognition. Indeed, as expected, authors of novels could be distinguished from those who wrote scientific texts. Our analysis demonstrated the suitability of the consistency indices, which can now be applied in other tasks, such as emotion recognition.

  15. Regulation loops for the ring magnet power supplies in the SSC accelerator complex

    SciTech Connect

    Tacconi, E.; Christiansen, C.

    1993-05-01

    The SSC complex consists of five cascaded accelerators: The linear accelerator (linac) and four synchrotrons: The low energy booster (LEB), the medium energy booster (MEB), the high energy booster (HEB), and the collider. Twelve- or 24-pulse phase-controlled SCR power supplies are used to energize the ring magnets. Each power supply has a voltage loop designed to regulate the voltage applied to the magnets. The voltage regulation loops for these synchrotrons and the current regulation for the LEB are analyzed in this work. The digital voltage regulator is fiber-optic isolated from the power converter. It has a closed-loop bandwidth of 150 Hz with band rejections for 60-Hz and 120-Hz perturbations. The LEB has a very precise current regulation system composed of a feedforward compensator, a fast feedback regulator, and a slow synchronous regulator. The current regulation design is corroborated by computer simulations.

  16. Investigation of electron-atom/molecule scattering resonances: Two complex multiconfigurational self-consistent field approaches

    SciTech Connect

    Samanta, Kousik; Yeager, Danny L.

    2015-01-22

    Resonances are temporarily bound states which lie in the continuum part of the Hamiltonian. If the electronic coordinates of the Hamiltonian are scaled (“dilated”) by a complex parameter, η = αe{sup iθ} (α, θ real), then its complex eigenvalues represent the scattering states (resonant and non-resonant) while the eigenvalues corresponding to the bound states and the ionization and the excitation thresholds remain real and unmodified. These make the study of these transient species amenable to the bound state methods. We developed a quadratically convergent multiconfigurational self-consistent field method (MCSCF), a well-established bound-state technique, combined with a dilated Hamiltonian to investigate resonances. This is made possible by the adoption of a second quantization algebra suitable for a set of “complex conjugate biorthonormal” spin orbitals and a modified step-length constraining algorithm to control the walk on the complex energy hypersurface while searching for the stationary point using a multidimensional Newton-Raphson scheme. We present our computational results for the {sup 2}PBe{sup −} shape resonances using two different computationally efficient methods that utilize complex scaled MCSCF (i.e., CMCSCF). These two methods are to straightforwardly use CMCSCF energy differences and to obtain energy differences using an approximation to the complex multiconfigurational electron propagator. It is found that, differing from previous computational studies by others, there are actually two {sup 2}PBe{sup −} shape resonances very close in energy. In addition, N{sub 2} resonances are examined using one of these methods.

  17. Supramolecular Complex Antioxidant Consisting of Vitamins C, E and Hydrophilic-Hydrophobic Silica Nanoparticles

    NASA Astrophysics Data System (ADS)

    Laguta, I. V.; Kuzema, P. O.; Stavinskaya, O. N.; Kazakova, O. A.

    Samples with varied amount of surface trimethylsilyl groups were obtained via gas-phase chemical modification of silica nanoparticles. The biocompatibility tests conducted in erythrocyte suspension have shown that hydrophobization of silica decreases its damaging effect to the cells. Being wettable in aqueous media, partially silylated silicas have higher affinity to hydrophobic bioactive molecules in comparison with the initial silica. Novel antioxidant consisting of vitamins C and E and silica with 40% of surface trimethylsilyl groups was formulated. It was found that supramolecular complexes are formed on the silica surface due to the affinity of water- and fat-soluble antioxidants to hydrophilic silanol and hydrophobic trimethylsilyl groups, respectively. Test reactions (total phenolic index determination, DPPH test) and in vitro studies (spectral analysis of erythrocyte suspensions undergoing UV irradiation) revealed the correlation between antioxidant activity of the complex antioxidant and the vitamins’ content. The antioxidant remained active during long-term storage under standard conditions.

  18. Supramolecular Complex Antioxidant Consisting of Vitamins C, E and Hydrophilic-Hydrophobic Silica Nanoparticles

    NASA Astrophysics Data System (ADS)

    Laguta, I. V.; Kuzema, P. O.; Stavinskaya, O. N.; Kazakova, O. A.

    Samples with varied amount of surface trimethylsilyl groups were obtained via gas-phase chemical modification of silica nanoparticles. The biocompatibility tests conducted in erythrocyte suspension have shown that hydrophobization of silica decreases its damaging effect to the cells. Being wettable in aqueous media, partially silylated silicas have higher affinity to hydrophobic bioactive molecules in comparison with the initial silica. Novel antioxidant consisting of vitamins C and E and silica with 40% of surface trimethylsilyl groups was formulated. It was found that supramolecular complexes are formed on the silica surface due to the affinity of water- and fat-soluble antioxidants to hydrophilic silanol and hydrophobic trimethylsilyl groups, respectively. Test reactions (total phenolic index determination, DPPH test) and in vitro studies (spectral analysis of erythrocyte suspensions undergoing UV irradiation) revealed the correlation between antioxidant activity of the complex antioxidant and the vitamins' content. The antioxidant remained active during long-term storage under standard conditions.

  19. Consistent global structures of complex RNA states through multidimensional chemical mapping

    PubMed Central

    Cheng, Clarence Yu; Chou, Fang-Chieh; Kladwang, Wipapat; Tian, Siqi; Cordero, Pablo; Das, Rhiju

    2015-01-01

    Accelerating discoveries of non-coding RNA (ncRNA) in myriad biological processes pose major challenges to structural and functional analysis. Despite progress in secondary structure modeling, high-throughput methods have generally failed to determine ncRNA tertiary structures, even at the 1-nm resolution that enables visualization of how helices and functional motifs are positioned in three dimensions. We report that integrating a new method called MOHCA-seq (Multiplexed •OH Cleavage Analysis with paired-end sequencing) with mutate-and-map secondary structure inference guides Rosetta 3D modeling to consistent 1-nm accuracy for intricately folded ncRNAs with lengths up to 188 nucleotides, including a blind RNA-puzzle challenge, the lariat-capping ribozyme. This multidimensional chemical mapping (MCM) pipeline resolves unexpected tertiary proximities for cyclic-di-GMP, glycine, and adenosylcobalamin riboswitch aptamers without their ligands and a loose structure for the recently discovered human HoxA9D internal ribosome entry site regulon. MCM offers a sequencing-based route to uncovering ncRNA 3D structure, applicable to functionally important but potentially heterogeneous states. DOI: http://dx.doi.org/10.7554/eLife.07600.001 PMID:26035425

  20. A magnetohydrodynamic model of the M87 jet. II. Self-consistent quad-shock jet model for optical relativistic motions and particle acceleration

    SciTech Connect

    Nakamura, Masanori

    2014-04-20

    We describe a new paradigm for understanding both relativistic motions and particle acceleration in the M87 jet: a magnetically dominated relativistic flow that naturally produces four relativistic magnetohydrodynamic (MHD) shocks (forward/reverse fast and slow modes). We apply this model to a set of optical super- and subluminal motions discovered by Biretta and coworkers with the Hubble Space Telescope during 1994-1998. The model concept consists of ejection of a single relativistic Poynting jet, which possesses a coherent helical (poloidal + toroidal) magnetic component, at the remarkably flaring point HST-1. We are able to reproduce quantitatively proper motions of components seen in the optical observations of HST-1 with the same model we used previously to describe similar features in radio very long baseline interferometry observations in 2005-2006. This indicates that the quad relativistic MHD shock model can be applied generally to recurring pairs of super/subluminal knots ejected from the upstream edge of the HST-1 complex as observed from radio to optical wavelengths, with forward/reverse fast-mode MHD shocks then responsible for observed moving features. Moreover, we identify such intrinsic properties as the shock compression ratio, degree of magnetization, and magnetic obliquity and show that they are suitable to mediate diffusive shock acceleration of relativistic particles via the first-order Fermi process. We suggest that relativistic MHD shocks in Poynting-flux-dominated helical jets may play a role in explaining observed emission and proper motions in many active galactic nuclei.

  1. Dynamic Self-Consistent Field Theory of Inhomogeneous Complex Fluids Under Shear

    NASA Astrophysics Data System (ADS)

    Mihajlovic, Maja; Lo, Tak Shing; Shnidman, Yitzhak

    2003-03-01

    Understanding and predicting the interplay between morphology and rheology of sheared, inhomogeneous, complex fluids is of great importance. Yet modeling of such phenomena is in its infancy. We have developed a novel dynamic self-consistent field (DSCF) theory that makes possible detailed computational study of such phenomena. Our DSCF theory couples the time evolution of chain conformation statistics with probabilistic transport equations for volume fractions and momenta, based on local conservation laws formulated on a segmental scale. To generate chain conformation statistics, we are using a modification of the lattice random walk formalism of Scheutjens and Fleer. Their static SCF theory is limited to equilibrium systems, since probability distributions are obtained by free energy minimization, assuming isotropic Gaussian chain conformations. In contrast, our DSCF approach accounts for explicit time evolution of the segmental and (anisotropic) stepping probabilities used for generating chain conformations. We will present highlights of DSCF studies of a variety of inhomogenous fluids containing homopolymers, block copolymers and nanoparticles.

  2. Progress Towards Doubling the Beam Power at Fermilab's Accelerator Complex

    SciTech Connect

    Kourbanis, ioanis

    2014-06-01

    After a 14 month shutdown accelerator modifications and upgrades are in place to allow us doubling of the Main Injector beam power. We will discuss the past MI high power operation and the current progress towards doubling the power.

  3. Chick myotendinous antigen. II. A novel extracellular glycoprotein complex consisting of large disulfide-linked subunits.

    PubMed

    Chiquet, M; Fambrough, D M

    1984-06-01

    This report describes the biochemical characterization of a novel extracellular matrix component, " myotendinous antigen," which appears early in chick limb morphogenesis at sites connecting developing muscle fibers, tendons, and bone ( Chiquet , M., and D. Fambrough , 1984; J. Cell Biol., 98:1926-1936). This extracellular matrix antigen is a major component of the secretory proteins released into the medium by fibroblast and muscle cultures; the soluble form is characterized here. This form of myotendinous antigen is a large glycoprotein complex consisting of several disulfide linked subunits (Mr approximately 150,000-240,000). The differently sized antigen subunits are related, since they yielded very similar proteolytic cleavage patterns. M1 antibody can bind to the denatured subunits. The antigen subunits, as well as a Mr approximately 80,000 pepsin-resistant antigenic domain derived from them, are resistant to bacterial collagenase. Despite possessing subunits similar in size to fibronectin, myotendinous antigen appears to be both structurally and antigenically unrelated to fibronectin or to other known extracellular matrix components. About seven times more M1 antigen per cell nucleus was released into the medium in fibroblast as compared to muscle cultures. In muscle conditioned medium, myotendinous antigen is noncovalently complexed to very high molecular weight material that could be heavily labeled by [3H]glucosamine and [35S]sulfate. This material is sensitive to chondroitinase ABC and hence appears to contain sulfated glycosaminoglycans. We speculate that myotendinous antigen might interact with proteoglycans on the surface of muscle fibers, thereby acting as a link to tendons. PMID:6202699

  4. Self-consistent field theory of polymer-ionic molecule complexation.

    PubMed

    Nakamura, Issei; Shi, An-Chang

    2010-05-21

    A self-consistent field theory is developed for polymers that are capable of binding small ionic molecules (adsorbates). The polymer-ionic molecule association is described by Ising-like binding variables, C(i) ((a))(kDelta)(=0 or 1), whose average determines the number of adsorbed molecules, n(BI). Polymer gelation can occur through polymer-ionic molecule complexation in our model. For polymer-polymer cross-links through the ionic molecules, three types of solutions for n(BI) are obtained, depending on the equilibrium constant of single-ion binding. Spinodal lines calculated from the mean-field free energy exhibit closed-loop regions where the homogeneous phase becomes unstable. This phase instability is driven by the excluded-volume interaction due to the single occupancy of ion-binding sites on the polymers. Moreover, sol-gel transitions are examined using a critical degree of conversion. A gel phase is induced when the concentration of adsorbates is increased. At a higher concentration of the adsorbates, however, a re-entrance from a gel phase into a sol phase arises from the correlation between unoccupied and occupied ion-binding sites. The theory is applied to a model system, poly(vinyl alcohol) and borate ion in aqueous solution with sodium chloride. Good agreement between theory and experiment is obtained. PMID:20499947

  5. Accelerating the Computation of Detailed Chemical Reaction Kinetics for Simulating Combustion of Complex Fuels

    SciTech Connect

    Sankaran, R.; Grout, R.

    2012-01-01

    Combustion of hydrocarbon fuels has been a very challenging scientific and engineering problem due to the complexity of turbulent flows and hydrocarbon reaction kinetics. There is an urgent need to develop an efficient modeling capability to accurately predict the combustion of complex fuels. Detailed chemical kinetic models for the surrogates of fuels such as gasoline, diesel and JP-8 consist of thousands of chemical species and Arrhenius reaction steps. Oxygenated fuels such as bio-fuels and heavier hydrocarbons, such as from newer fossil fuel sources, are expected to have a much more complex chemistry requiring increasingly larger chemical kinetic models. Such models are beyond current computational capability, except for homogeneous or partially stirred reactor type calculations. The advent of highly parallel multi-core processors and graphical processing units (GPUs) promises a steep increase in computational performance in the coming years. This paper will present a software framework that translates the detailed chemical kinetic models to high-performance code targeted for GPU accelerators.

  6. Accelerating the Computation of Detailed Chemical Reaction Kinetics for Simulating Combustion of Complex Fuels

    SciTech Connect

    Grout, Ray W

    2012-01-01

    Combustion of hydrocarbon fuels has been a very challenging scientific and engineering problem due to the complexity of turbulent flows and hydrocarbon reaction kinetics. There is an urgent need to develop an efficient modeling capability to accurately predict the combustion of complex fuels. Detailed chemical kinetic models for the surrogates of fuels such as gasoline, diesel and JP-8 consist of thousands of chemical species and Arrhenius reaction steps. Oxygenated fuels such as bio-fuels and heavier hydrocarbons, such as from newer fossil fuel sources, are expected to have a much more complex chemistry requiring increasingly larger chemical kinetic models. Such models are beyond current computational capability, except for homogeneous or partially stirred reactor type calculations. The advent of highly parallel multi-core processors and graphical processing units (GPUs) promises a steep increase in computational performance in the coming years. This paper will present a software framework that translates the detailed chemical kinetic models to high- performance code targeted for GPU accelerators.

  7. Status of the SPI for the JINR Accelerator Complex

    NASA Astrophysics Data System (ADS)

    Fimushkin, V. V.; Kovalenko, A. D.; Kutuzova, L. V.; Prokofichev, Yu. V.; Belov, A. S.; Turbabin, A. V.; Zubets, V. N.

    2016-02-01

    The Source of Polarized Ions (SPI) of deuterons and protons with nearly resonant charge-exchange plasma ionizer is under construction at the LHEP, JINR. The ↑D+ ( ↑H+) current output of the source is expected to be at a level of 10mA. The polarization will be up to 90% of the maximal vector (±1) for ↑D+ ( ↑H+) and tensor (+1, ‑ 2) polarization for ↑D+. Realization of the project is carried out in close cooperation with INR of the RAS (Moscow). The equipment available from the CIPIOS ion source (IUCF, Bloomington, USA) is partially used for the Dubna setup. The new source at the JINR NUCLOTRON accelerator facility will make it possible to increase the polarized deuteron beam intensity up to the level of 1010 d/pulse.

  8. The operation of the LHC accelerator complex (1/2)

    ScienceCinema

    None

    2011-10-06

    These lectures will give an overview of what happens when the LHC is in running mode. They are aimed at students working on the LHC experiments, but all those who are curious about what happens behind the scenes of the LHC are welcomed. You will learn all you always wanted to know about the LHC, and never had the courage to ask! The only pre-requisite is a basic, college-level, knowledge of EM and of the principles that allow to steer charged beams. Topics covered will include, among others: - the description of the injector chain, from the generation of the protons, to the delivery of bunches to the LHC. - the discussion of the steps required to accelerate the beams in the LHC, to bring them into collision, and to control the luminosity at the interaction points. - the description of the monitoring tools available to the LHC operators, and an explanation of the various plots and panels that can be found on the LHC web pages. o Lecture 1: Wednesday April 7, 10-11am o Lecture 2: Friday April 9, 10-11am The lectures will be webcast, recorded and archived. Coffee will be served before the lectures, starting at 9:45

  9. The operation of the LHC accelerator complex (2/2)

    ScienceCinema

    None

    2011-10-06

    These lectures will give an overview of what happens when the LHC is in running mode. They are aimed at students working on the LHC experiments, but all those who are curious about what happens behind the scenes of the LHC are welcomed. You will learn all you always wanted to know about the LHC, and never had the courage to ask! The only pre-requisite is a basic, college-level, knowledge of EM and of the principles that allow to steer charged beams. Topics covered will include, among others: - the description of the injector chain, from the generation of the protons, to the delivery of bunches to the LHC. - the discussion of the steps required to accelerate the beams in the LHC, to bring them into collision, and to control the luminosity at the interaction points. - the description of the monitoring tools available to the LHC operators, and an explanation of the various plots and panels that can be found on the LHC web pages. o Lecture 1: Wednesday April 7, 10-11am o Lecture 2: Friday April 9, 10-11am The lectures will be webcast, recorded and archived. Coffee will be served before the lectures, starting at 9:45

  10. The operation of the LHC accelerator complex (1/2)

    SciTech Connect

    2010-04-07

    These lectures will give an overview of what happens when the LHC is in running mode. They are aimed at students working on the LHC experiments, but all those who are curious about what happens behind the scenes of the LHC are welcomed. You will learn all you always wanted to know about the LHC, and never had the courage to ask! The only pre-requisite is a basic, college-level, knowledge of EM and of the principles that allow to steer charged beams. Topics covered will include, among others: - the description of the injector chain, from the generation of the protons, to the delivery of bunches to the LHC. - the discussion of the steps required to accelerate the beams in the LHC, to bring them into collision, and to control the luminosity at the interaction points. - the description of the monitoring tools available to the LHC operators, and an explanation of the various plots and panels that can be found on the LHC web pages. o Lecture 1: Wednesday April 7, 10-11am o Lecture 2: Friday April 9, 10-11am The lectures will be webcast, recorded and archived. Coffee will be served before the lectures, starting at 9:45

  11. The operation of the LHC accelerator complex (2/2)

    SciTech Connect

    2010-04-09

    These lectures will give an overview of what happens when the LHC is in running mode. They are aimed at students working on the LHC experiments, but all those who are curious about what happens behind the scenes of the LHC are welcomed. You will learn all you always wanted to know about the LHC, and never had the courage to ask! The only pre-requisite is a basic, college-level, knowledge of EM and of the principles that allow to steer charged beams. Topics covered will include, among others: - the description of the injector chain, from the generation of the protons, to the delivery of bunches to the LHC. - the discussion of the steps required to accelerate the beams in the LHC, to bring them into collision, and to control the luminosity at the interaction points. - the description of the monitoring tools available to the LHC operators, and an explanation of the various plots and panels that can be found on the LHC web pages. o Lecture 1: Wednesday April 7, 10-11am o Lecture 2: Friday April 9, 10-11am The lectures will be webcast, recorded and archived. Coffee will be served before the lectures, starting at 9:45

  12. Studies of a colorimetric array consisted of metalloporphrins and Pt complexes

    NASA Astrophysics Data System (ADS)

    Luo, Jing; Ma, Tengshuang; Li, Lu; Pan, Pinghua; Xu, Jianhua; Jiang, Yadong; Yang, Yajie

    2010-10-01

    We have studied the absorption of volatile organic compounds (VOCs) and vapochromic characterization by a colorimetric array based on metalloporphyrins and Pt complexes: ZnTPP, CuTPP, and [Pt(Me2bizmpy)Cl]Cl (TPP=tetraphenylporphrins; Me2bzimpy=2,6-bis(N-methylbenzimidazol-2-yl)pyridine). The array was exposed to pyridine, tetrahydrofuran, ethyl acetate, methanol and acetonitrile. The experimental results demonstrate that the Pt complexes are sensitive to methanol and acetonitrile, while ZnTPP and CuTPP present an obvious response to pyridine, tetrahydrofuran and ethyl acetate. The response behaviors are reversible and rapid within seconds. The changes of Ultra Violet Visible (UV-visible) absorption spectrums of ZnTPP and CuTPP LB films before and after exposure upon the VOCs are also discussed. In addition, the differences of absorption spectrum of Pt complexes dissolved in several solvents are mentioned. The results show that [Pt(Me2bizmpy)Cl]Cl, CuTPP and ZnTPP exhibit reversible changes of action with VOCs, and they show promising future to be used in Smell-Seeing Electronic Nose to identify VOCs.

  13. A self-consistent three-wave coupling model with complex linear frequencies

    SciTech Connect

    Kim, J.-H.; Terry, P. W.

    2011-09-15

    A three-wave coupling model with complex linear frequencies is investigated for the nonlinear interaction in a triad that has linearly unstable and stable modes. Time scales associated with linear and nonlinear physics are identified and compared with features of the frequency spectrum. From appropriate time scales, the frequency spectra are well characterized even in the transition to the steady state. The nonlinear time scales that best match spectral features are the nonlinear frequency of the fixed point and a frequency that depends on the amplitude displacement from the fixed point through the large-amplitude Jacobian elliptic solution. Two limited efforts to model the effect of other triads suggest robustness in the single triad results.

  14. Size estimation of complexes consisting of hairpin DNAs bound to an assembler-strand. [Abstract only

    NASA Technical Reports Server (NTRS)

    Baumann, Ulrich

    1994-01-01

    In connection with a model of a primitive translation based entirely on nucleic acids the structural requirements and interactions of small nucleic acids were studied. As shown previously hairpins bind to a complementary single-strand by base pairs of their loop nucleotides if the loop contains at least five nucleotides (Baumann et al 1987). Here, the question is approached to which degree a single-strand, the assembler-strand, is occupied with hairpin molecules. A gapless occupation would allow the close proximity necessary for the assumed peptide bond formation by hairpins bearing an amino acid at their 3'-end. Oligo(dC)(sub n), n = 12, 15, 18, and the investigated hairpins form complexes which are detectable under nondenaturing electrophoretic conditions. The size range is estimated to be 3-4 hairpin molecules to one assembler molecule when oligo(dC)(sub n), n = 15, 18, is used. Due to the limitation of the method, dependence of the migration velocity on the shape which is unique and thus limits the use of marker nucleic acids, and due to the uncertainty if the ends of the assembler form base pairs, a gapless occupation of the assembler is conceivable but not proven.

  15. Complex step derivative approximation of consistent tangent operators for viscoelasticity based on fractional calculus

    NASA Astrophysics Data System (ADS)

    Hürkamp, André; Tanaka, Masato; Kaliske, Michael

    2015-12-01

    In this contribution, the convergence behaviour of simulations with nonlinear viscoelastic models for rubber-like materials using fractional derivatives is investigated. Based on the complex step derivative approximation, numerical approximation schemes for tangent operators on the local and global algorithmic level are analysed. Material models including fractional derivatives usually exhibit numerical difficulties, since the entire stress history of the material has to be considered for the current stress state. Non-classical methods can help to reduce the numerical effort, but the convergence behaviour is not perfect. In this paper, a classical and a non-classical fractional element based viscoelastic material formulation are analysed. The local and the global convergence rate using analytically and numerically derived tangents are investigated and compared to the convergence behaviour of a standard nonlinear viscoelastic model. Numerical examples on rubber materials are exploited, showing the performance of the proposed methods. It can be proven that the outlined numerical differentiation schemes improve the convergence rate, as well as reduce the computation time for the fractional element based material models.

  16. Future Development Of The Flerov Laboratory Accelerator Complex (Project DRIBs-III)

    NASA Astrophysics Data System (ADS)

    Gulbekian, G. G.; Dmitriev, S. N.; Itkis, M. G.; Oganessian, Yu. Ts.; Popeko, A. G.

    2010-04-01

    Future development of the FLNR accelerator complex (project DRIBs-III) includes modernization of existing cyclotrons, construction of a new experimental hall, creation of a new high current cyclotron and of next generation experimental set-ups. Realization of the project is planned for 2010-2016.

  17. Hydrologic consistency as a basis for assessing complexity of monthly water balance models for the continental United States

    NASA Astrophysics Data System (ADS)

    Martinez, Guillermo F.; Gupta, Hoshin V.

    2011-12-01

    Methods to select parsimonious and hydrologically consistent model structures are useful for evaluating dominance of hydrologic processes and representativeness of data. While information criteria (appropriately constrained to obey underlying statistical assumptions) can provide a basis for evaluating appropriate model complexity, it is not sufficient to rely upon the principle of maximum likelihood (ML) alone. We suggest that one must also call upon a "principle of hydrologic consistency," meaning that selected ML structures and parameter estimates must be constrained (as well as possible) to reproduce desired hydrological characteristics of the processes under investigation. This argument is demonstrated in the context of evaluating the suitability of candidate model structures for lumped water balance modeling across the continental United States, using data from 307 snow-free catchments. The models are constrained to satisfy several tests of hydrologic consistency, a flow space transformation is used to ensure better consistency with underlying statistical assumptions, and information criteria are used to evaluate model complexity relative to the data. The results clearly demonstrate that the principle of consistency provides a sensible basis for guiding selection of model structures and indicate strong spatial persistence of certain model structures across the continental United States. Further work to untangle reasons for model structure predominance can help to relate conceptual model structures to physical characteristics of the catchments, facilitating the task of prediction in ungaged basins.

  18. Self-consistent Monte Carlo simulations of proton acceleration in coronal shocks: Effect of anisotropic pitch-angle scattering of particles

    NASA Astrophysics Data System (ADS)

    Afanasiev, A.; Battarbee, M.; Vainio, R.

    2015-12-01

    Context. Solar energetic particles observed in association with coronal mass ejections (CMEs) are produced by the CME-driven shock waves. The acceleration of particles is considered to be due to diffusive shock acceleration (DSA). Aims: We aim at a better understanding of DSA in the case of quasi-parallel shocks, in which self-generated turbulence in the shock vicinity plays a key role. Methods: We have developed and applied a new Monte Carlo simulation code for acceleration of protons in parallel coronal shocks. The code performs a self-consistent calculation of resonant interactions of particles with Alfvén waves based on the quasi-linear theory. In contrast to the existing Monte Carlo codes of DSA, the new code features the full quasi-linear resonance condition of particle pitch-angle scattering. This allows us to take anisotropy of particle pitch-angle scattering into account, while the older codes implement an approximate resonance condition leading to isotropic scattering. We performed simulations with the new code and with an old code, applying the same initial and boundary conditions, and have compared the results provided by both codes with each other, and with the predictions of the steady-state theory. Results: We have found that anisotropic pitch-angle scattering leads to less efficient acceleration of particles than isotropic. However, extrapolations to particle injection rates higher than those we were able to use suggest the capability of DSA to produce relativistic particles. The particle and wave distributions in the foreshock as well as their time evolution, provided by our new simulation code, are significantly different from the previous results and from the steady-state theory. Specifically, the mean free path in the simulations with the new code is increasing with energy, in contrast to the theoretical result.

  19. A self-consistent view on plasma-neutral interaction near a wall: plasma acceleration by momentum removal and heating by cold walls

    NASA Astrophysics Data System (ADS)

    van Rooij, Gerard; den Harder, Niek; Minea, Teofil; Shumack, Amy; de Blank, H.; Plasma Physics Team

    2014-10-01

    In plasma physics, material walls are generally regarded as perfect sinks for charged particles and their energy. A special case arises when the wall efficiently reflects the neutralized plasma particles (with a significant portion of their kinetic energy) and at the same time the upstream plasma is of sufficiently high density to yield strong neutral-ion coupling (i.e. reflected energy and momentum will not escape from the plasma). Under these conditions, plasma-surface interaction will feedback to the upstream plasma and a self-consistent view on the coupling between plasma and neutrals is required for correct prediction of plasma conditions and plasma-surface interaction. Here, an analytical and numerical study of the fluid equations is combined with experiments (in hydrogen and argon) to construct such a self-consistent view. It shows how plasma momentum removal builds up upstream pressure and causes plasma acceleration towards the wall. It also shows how energy reflection causes plasma heating, which recycles part of the reflected power to the wall and induces additional flow acceleration due to local sound speed increase. The findings are relevant as generic textbook example and are at play in the boundary plasma of fusion devices.

  20. Energy transfer from the singlet levels of diketones and dyes to lanthanide ions in nanoparticles consisting of their diketonate complexes

    NASA Astrophysics Data System (ADS)

    Mironov, L. Yu.; Sveshnikova, E. B.; Ermolaev, V. L.

    2014-06-01

    The energy transfer from the S 1 levels of p-phenylbenzoyltrifluoroacetone (PhBTA) and dyes to different Ln3+ ions is studied in nanoparticles (NPs) composed of complexes of this diketone with Ln3+ and 1,10-phenanthroline (phen) and doped with dye molecules. The quenching rate constants in the NPs consisting from complexes of Pr3+, Nd3+, Sm3+, Eu3+, Ho3+, Er3+, and Tm3+ are determined from the data on the quenching of sensitized (cofluorescence) and ordinary fluorescence of coumarin 30 (C30) and rhodamine 6G (R6G). The quenching rate constants vary from ≤5 × 1011 to 1013 s-1 for the fluorescence quenching of PhBTA by different Ln3+ ions, while the quenching of dye fluorescence occurs at rates of the order of 109 s-1. In the case of complexes with the Pr3+ ions, the fluorescence quenching of PhBTA in NPs composed of its complexes is accompanied by sensitized luminescence of Pr3+. The quenching observed is due to a nonradiative energy transfer from the S 1 states of ligands and dyes to these ions. It is shown that in NPs composed of complexes with Eu3+, Yb3+, and Sm3+ the cofluorescence of C30 is quenched via the electron-transfer mechanism. The study of quenching of cofluorescence and fluorescence of dyes in NPs composed of mixed complexes of La3+ and Nd3+ (Ho3+) shows that the observed quenching of fluorescence and cofluorescence is governed mainly by the quenching of the S 1 state of dyes when the Nd3+ (Ho3+) content does not exceed 5-10% and by the quenching of the S 1 state of a ligand when the Nd3+ (Ho3+) content exceeds 50%. It is assumed that the high rate constant of energy transfer from the S 1 level of ligands to ions Pr3+, Nd3+, Ho3+, Er3+, and Tm3+ in NPs composed of beta-diketonate complexes is caused by exchange interactions.

  1. Generalized control and data access at the LANSCE Accelerator Complex -- Gateway, migrators, and other servers

    SciTech Connect

    Schaller, S.C.; Oothoudt, M.A.

    1995-12-01

    All large accelerator control systems eventually outlast the technologies with which they were built. This has happened several times during the lifetime of the accelerators at Los Alamos in the LAMPF/PSR beam delivery complex. Most recently, the EPICS control system has been integrated with the existing LAMPF and PSR control systems. In this paper, the authors discuss the provisions that were made to provide uniform, and nearly transparent sharing of data among the three control systems. The data sharing mechanisms have now been in use during a very successful beam production period. They comment on the successes and failures of the project and indicate the control system properties that make such sharing possible.

  2. A self-consistent and environment-dependent Hamiltonian for large-scale simulations of complex nanostructures

    NASA Astrophysics Data System (ADS)

    Yu, Ming; Wu, S. Y.; Jayanthi, C. S.

    2009-11-01

    This review is devoted to the development of a robust semi-empirical Hamiltonian for quantum-mechanics-based simulations. The Hamiltonian referred as self-consistent (SC) and environment-dependent (ED) Hamiltonian is developed in the framework of linear combination of atomic orbitals (LCAO) and includes multi-center electron-ion and electron-electron interactions. Furthermore, the framework allows for a self-consistent treatment of charge-redistributions. The parameterized Hamiltonian matrix elements and overlap functions are obtained by fitting them to accurate first-principles database of properties corresponding to clusters and bulk phases of materials. The total energy includes the band structure energy, the correction term from the double-counting of electrons, and ion-ion repulsions, where the band structure energy is obtained by solving a generalized eigenvalue equation. Linear scaling algorithms for large-scale simulations of materials have also been incorporated. The present approach goes beyond the traditional two-center tight-binding Hamiltonians in terms of its accuracy and transferability and allows the study of system sizes that are beyond the scope of ab-initio simulations. We have studied a wide-variety of complex materials and complex phenomena using the SCED-LCAO MD that include: (i) the structure and stability of bucky-diamond carbon clusters and their phase transformations upon annealing, (ii) the initial stage of growth of single-wall carbon nanotubes (SWCNTs), and (iii) structural and electronic properties of bucky-diamond SiC clusters and SiC nanowires (NWs). The successful outcome of these case studies is a testament to the transferability of the Hamiltonian to different types of atomic environments ( i.e., co-ordinations and bonding configurations).

  3. Evidence of symptom profiles consistent with posttraumatic stress disorder and complex posttraumatic stress disorder in different trauma samples

    PubMed Central

    Elklit, Ask; Hyland, Philip; Shevlin, Mark

    2014-01-01

    Background The International Classification of Diseases, 11th version (ICD-11), proposes two related stress and trauma-related disorders, posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD). A diagnosis of CPTSD requires that in addition to the PTSD symptoms, an individual must also endorse symptoms in three major domains: (1) affective dysregulation, (2) negative self-concepts, and (3) interpersonal problems. This study aimed to determine if the naturally occurring distribution of symptoms in three groups of traumatised individuals (bereavement, sexual victimisation, and physical assault) were consistent with the ICD-11, PTSD, and CPTSD specification. The study also investigated whether these groups differed on a range of other psychological problems. Methods and Results Participants completed self-report measures of each symptom group and latent class analyses consistently found that a three class solution was best. The classes were “PTSD only,” “CPTSD,” and “low PTSD/CPTSD.” These classes differed significantly on measures of depression, anxiety, dissociation, sleep disturbances, somatisation, interpersonal sensitivity, and aggression. The “CPTSD” class in the three samples scored highest on all the variables, with the “PTSD only” class scoring lower and the “low PTSD/CPTSD” class the lowest. Conclusion This study provides evidence to support the diagnostic structure of CPTSD and indicted that CPTSD is associated with a broad range of other psychological problems. PMID:24851144

  4. Frataxin Accelerates [2Fe-2S] Cluster Formation on the Human Fe–S Assembly Complex

    PubMed Central

    Fox, Nicholas G.; Das, Deepika; Chakrabarti, Mrinmoy; Lindahl, Paul A.; Barondeau, David P.

    2015-01-01

    Iron–sulfur (Fe–S) clusters function as protein cofactors for a wide variety of critical cellular reactions. In human mitochondria, a core Fe–S assembly complex [called SDUF and composed of NFS1, ISD11, ISCU2, and frataxin (FXN) proteins] synthesizes Fe–S clusters from iron, cysteine sulfur, and reducing equivalents and then transfers these intact clusters to target proteins. In vitro assays have relied on reducing the complexity of this complicated Fe–S assembly process by using surrogate electron donor molecules and monitoring simplified reactions. Recent studies have concluded that FXN promotes the synthesis of [4Fe-4S] clusters on the mammalian Fe–S assembly complex. Here the kinetics of Fe–S synthesis reactions were determined using different electron donation systems and by monitoring the products with circular dichroism and absorbance spectroscopies. We discovered that common surrogate electron donor molecules intercepted Fe–S cluster intermediates and formed high-molecular weight species (HMWS). The HMWS are associated with iron, sulfide, and thiol-containing proteins and have properties of a heterogeneous solubilized mineral with spectroscopic properties remarkably reminiscent of those of [4Fe-4S] clusters. In contrast, reactions using physiological reagents revealed that FXN accelerates the formation of [2Fe-2S] clusters rather than [4Fe-4S] clusters as previously reported. In the preceding paper [Fox, N. G., et al. (2015) Biochemistry 54, DOI: 10.1021/bi5014485], [2Fe-2S] intermediates on the SDUF complex were shown to readily transfer to uncomplexed ISCU2 or apo acceptor proteins, depending on the reaction conditions. Our results indicate that FXN accelerates a rate-limiting sulfur transfer step in the synthesis of [2Fe-2S] clusters on the human Fe–S assembly complex. PMID:26016518

  5. Ion pre-acceleration in fully self-consistent particle-in-cell simulations of supercritical perpendicular reforming shocks in multiple ion species plasmas

    SciTech Connect

    Rekaa, V. L.; Chapman, S. C.; Dendy, R. O.

    2014-08-10

    Supernova remnant and heliopause termination shock plasmas may contain significant populations of minority heavy ions, with relative number densities n{sub α}/n{sub i} up to 50%. Preliminary kinetic simulations of collisionless shocks in these environments showed that the reformation cycle and acceleration mechanisms at quasi-perpendicular shocks can depend on the value of n{sub α}/n{sub i} . Shock reformation unfolds on ion spatio-temporal scales, requiring fully kinetic simulations of particle dynamics, together with the self-consistent electric and magnetic fields. This paper presents the first set of particle-in-cell simulations for two ion species, protons (n{sub p} ) and α-particles (n{sub α}), with differing mass and charge-to-mass ratios, that spans the entire range of n{sub α}/n{sub i} from 0% to 100%. The interplay between the differing gyro length scales and timescales of the ion species is crucial to the time-evolving phenomenology of the shocks, the downstream turbulence, and the particle acceleration at different n{sub α}/n{sub i} . We show how the overall energization changes with n{sub α}/n{sub i} , and relate this to the processes individual ions undergo in the shock region and in the downstream turbulence, and to the power spectra of magnetic field fluctuations. The crossover between shocks dominated by the respective ion species happens when n{sub α}/n{sub i} = 25%, and minority ion energization is strongest in this regime. Energization of the majority ion species scales with injection energy. The power spectrum of the downstream turbulence includes peaks at sequential ion cyclotron harmonics, suggestive of ion ring-beam collective instability.

  6. Structure determination of chemisorbed chirality transfer complexes: Accelerated STM analysis and exchange-correlation functional sensitivity

    NASA Astrophysics Data System (ADS)

    Groves, M. N.; Goubert, G.; Rasmussen, A. M. H.; Dong, Y.; Lemay, J.-C.; Demers-Carpentier, V.; McBreen, P. H.; Hammer, B.

    2014-11-01

    Linking STM images to atomic positions determined by DFT calculations is an important step in characterizing the intermolecular interactions at play in many surface processes including asymmetric hydrogenation on heterogeneous catalysts. An accelerated data extraction method is used to collect STM information on the geometry of complexes formed between the two substrates, 2,2,2-trifluoroacetophenone (TFAP) and 3,3,3-methyltrifluoropyruvate (MTFP), and the chiral modifier (R)-(+)-1-(1-naphthyl)ethylamine ((R)-NEA) on Pt(111). We present new experimental data for complexes formed by MTFP and the (R)-NEA-1 conformer along with a new and enlarged set of reformulated STM data that extends what was reported in previously published studies of complexed MTFP and TFAP. Atomic geometries based on DFT calculations using PBE, M06-L, and optB88-vdW exchange-correlation functionals will also be presented. It will be shown that both substrates have well-defined complexation geometries when interacting with the modifier and that the relative complexation energies are not markedly sensitive to the functional employed.

  7. Multi-cavity complex controller with vector simulator for TESLA technology linear accelerator

    NASA Astrophysics Data System (ADS)

    Czarski, Tomasz; Pozniak, Krzysztof T.; Romaniuk, Ryszard S.; Szewinski, Jaroslaw

    2008-01-01

    A digital control, as the main part of the Low Level RF system, for superconducting cavities of a linear accelerator is presented. The FPGA based controller, supported by MATLAB system, was developed to investigate a novel firmware implementation. The complex control algorithm based on the non-linear system identification is the proposal verified by the preliminary experimental results. The general idea is implemented as the Multi-Cavity Complex Controller (MCC) and is still under development. The FPGA based controller executes procedure according to the prearranged control tables: Feed-Forward, Set-Point and Corrector unit, to fulfill the required cavity performance: driving in the resonance during filling and field stabilization for the flattop range. Adaptive control algorithm is applied for the feed-forward and feedback modes. The vector Simulator table has been introduced for an efficient verification of the FPGA controller structure. Experimental results of the internal simulation, are presented for a cavity representative condition.

  8. Optical and X-Ray Observations of GRB 060526: A Complex Afterglow Consistent with an Achromatic Jet Break

    NASA Technical Reports Server (NTRS)

    Dai, X.; Halpern, J. P.; Morgan, N. D.; Armstrong, E.; Mirabal, N.; Haislip. J. B.; Reichart, D. E.; Stanek, K. Z.

    2007-01-01

    We obtained 98 R-band and 18 B, r', i' images of the optical afterglow of GRB 060526 (z = 3.21) with the MDM 1.3 m, 2.4 m, and the PROMPT telescopes at CTIO over the five nights following the burst trigger. Combining these data with other optical observations reported in GCN and the Swift XRT observations, we compare the optical and X-ray afterglow light curves of GRB 060526. Both the optical and X-ray afterglow light curves show rich features, such as flares and breaks. The densely sampled optical observations provide very good coverage at T > 10(exp 4) s. We observed a break at 2.4 x 10(exp 5) sin the optical afterglow light curve. Compared with the X-ray afterglow light curve, the break is consistent with an achromatic break supporting the beaming models of GRBs. However, the prebreak and postbreak temporal decay slopes are difficult to explain in simple afterglow models. We estimated a jet angle of theta(sub j) approx. 7deg and a prompt emission size of R(sub prompt) approx. 2 x 10(exp 14) cm. In addition, we detected several optical flares with amplitudes of (Delta)m approx. 0.2,0.6, and 0.2 mag. The X-ray afterglows detected by Swift have shown complicated decay patterns. Recently, many well-sampled optical afterglows also show decays with flares and multiple breaks. GRB 060526 provides an additional case of such a complex, well-observed optical afterglow. The accumulated well-sampled afterglows indicate that most of the optical afterglows are complex.

  9. Scalar Transport and Dispersion in Complex Terrain within a High Resolution Mass-Consistent Wind Modeling Framework

    NASA Astrophysics Data System (ADS)

    Wagenbrenner, N. S.; Edburg, S. L.; Lamb, B.; Forthofer, J.

    2012-12-01

    In areas of complex terrain, fine-scale changes in topography or vegetation substantially alter the flow field, and in turn, the transport and dispersion of air pollutants, pheromones, or other scalars. Thus, accurate modeling of scalar transport in complex topography requires accurate prediction of the flow field at a high spatial resolution. Mesoscale weather models typically operate on horizontal grids of 4 km or larger and are not capable of handling the effects of sub-grid complex terrain, such as wind speed-up over ridges, flow channeling in valleys, flow separation around terrain obstacles, and enhanced surface roughness from vegetation. In this paper we describe a scalar transport algorithm (advection and turbulent diffusion) used with WindNinja, a high-resolution mass-consistent wind model. WindNinja operates on a terrain-following coordinate system with a hexahedral cell mesh that grows in vertical size with height above the ground. A variational calculus approach is used in WindNinja that results in fast run times on the order of one minute for a 50 km x 50 km domain and 100 m horizontal resolution. The advection-diffusion algorithm uses a first order closure scheme for turbulent diffusion, where diffusivities are parameterized based on mixing length theory and modified as a function of atmospheric stability. We initialize WindNinja simulations with output from mesoscale weather forecasts using the Weather Research and Forecasting (WRF) model to capture the large-scale atmospheric flows and stability conditions. Model performance is evaluated against field data collected under a range of conditions at different locations including a multi-day continuous tracer gas dispersion experiment in an orchard located on rolling terrain in eastern Washington and a post-wildfire PM10 monitoring campaign in SE Idaho. The combination of fast run times, low computational demands, and explicit treatment of terrain and vegetation at a high spatial resolution are expected

  10. Complex microstructures of ABC triblock copolymer thin films directed by polymer brushes based on self-consistent field theory.

    PubMed

    Jiang, Zhibin; Xu, Chang; Qiu, Yu Dong; Wang, Xiaoliang; Zhou, Dongshan; Xue, Gi

    2014-01-01

    The morphology and the phase diagram of ABC triblock copolymer thin film directed by polymer brushes are investigated by the self-consistent field theory in three dimensions. The polymer brushes coated on the substrate can be used as a good soft template to tailor the morphology of the block copolymer thin films compared with those on the hard substrates. The polymer brush is identical with the middle block B. By continuously changing the composition of the block copolymer, the phase diagrams are constructed for three cases with the fixed film thickness and the brush density: identical interaction parameters, frustrated and non-frustrated cases. Some ordered complex morphologies are observed: parallel lamellar phase with hexagonally packed pores at surfaces (LAM3 (ll) -HFs), perpendicular lamellar phase with cylinders at the interface (LAM(⊥)-CI), and perpendicular hexagonally packed cylinders phase with rings at the interface (C2 (⊥)-RI). A desired direction (perpendicular or parallel to the coated surfaces) of lamellar phases or cylindrical phases can be obtained by varying the composition and the interactions between different blocks. The phase diagram of ABC triblock copolymer thin film wetted between the polymer brush-coated surfaces is very useful in designing the directed pattern of ABC triblock copolymer thin film. PMID:25114650

  11. mRNA export through an additional cap-binding complex consisting of NCBP1 and NCBP3

    PubMed Central

    Gebhardt, Anna; Habjan, Matthias; Benda, Christian; Meiler, Arno; Haas, Darya A.; Hein, Marco Y.; Mann, Angelika; Mann, Matthias; Habermann, Bianca; Pichlmair, Andreas

    2015-01-01

    The flow of genetic information from DNA to protein requires polymerase-II-transcribed RNA characterized by the presence of a 5′-cap. The cap-binding complex (CBC), consisting of the nuclear cap-binding protein (NCBP) 2 and its adaptor NCBP1, is believed to bind all capped RNA and to be necessary for its processing and intracellular localization. Here we show that NCBP1, but not NCBP2, is required for cell viability and poly(A) RNA export. We identify C17orf85 (here named NCBP3) as a cap-binding protein that together with NCBP1 forms an alternative CBC in higher eukaryotes. NCBP3 binds mRNA, associates with components of the mRNA processing machinery and contributes to poly(A) RNA export. Loss of NCBP3 can be compensated by NCBP2 under steady-state conditions. However, NCBP3 becomes pivotal under stress conditions, such as virus infection. We propose the existence of an alternative CBC involving NCBP1 and NCBP3 that plays a key role in mRNA biogenesis. PMID:26382858

  12. Effect of cyclodextrin derivation and amorphous state of complex on accelerated degradation of ziprasidone.

    PubMed

    Hong, Jinyang; Shah, Jaymin C; Mcgonagle, Maura D

    2011-07-01

    Inclusion complexes of ziprasidone with several β-cyclodextrins [β-CDs; sulfobutylether-β-cyclodextrins (SBEβCD), hydroxypropyl-β-cyclodextrins (HPβCD), methyl-β-cyclodextrins (MβCD), and carboxyethyl-β-cyclodextrins (CEβCD)] were prepared and solution stability was evaluated at elevated temperature. Solid-state stability was assessed by subjecting various CD complexes of ziprasidone, spray-dried dispersion (SDD), partially crystalline ziprasidone-SBEβCD salts, and the physical mixture of ziprasidone-SBEβCD to γ-irradiation. Degradant I was formed by oxidation of ziprasidone, which upon aldol condensation with ziprasidone formed degradant II in both solution and solid states. In the solution state, CD complexes with electron-donating side chains, such as SBEβCD and CEβCD, produced the highest oxidative degradation followed by HPβCD with 6, 3, and 4 degrees of substitution. In the solid state, crystalline drug substance and physical mixture of crystalline drug-SBEβCD showed very little to no degradation. In contrast, amorphous βCD, MβCD, CEβCD, and SBEβCD complexes as well as the amorphous SDD exhibited greatest extent of oxidative degradation. Results suggest that electron-donating side chains of the derivatized CD interact with transition state of the oxidation reaction and catalyze drug degradation in solution, However, higher mobility in the amorphous state of CD-drug complexes promoted chemical instability of ziprasidone under accelerated conditions irrespective of the chemical nature of the side chain on CD. PMID:21283987

  13. Development of an H- ion source for Japan Proton Accelerator Research Complex upgradea)

    NASA Astrophysics Data System (ADS)

    Ohkoshi, K.; Namekawa, Y.; Ueno, A.; Oguri, H.; Ikegami, K.

    2010-02-01

    A cesium (Cs) free H- ion source driven with a lanthanum hexaboride (LaB6) filament was adopted as an ion source for the first stage of the Japan Proton Accelerator Research Complex (J-PARC). At present, the maximum H- ion current produced by the ion source is 38 mA, using which J-PARC can produce a proton beam power of 0.6 MW by accelerating it with the 181 MeV linac and the 3 GeV rapid cycling synchrotron. In order to satisfy the beam power of 1 MW required for the second stage of the J-PARC in the near future, we have to increase the ion current to more than 60 mA. Therefore, we have started to develop a Cs-seeded ion source by adding an external Cs-seeding system to a J-PARC test ion source that has a structure similar to that of the J-PARC ion source except for the fact that the plasma chamber is slightly larger. As a result, a H- ion current of more than 70 mA was obtained from the ion source using a tungsten filament instead of a LaB6 filament with a low arc discharge power of 15 kW (100 V, 150 A).

  14. Future directions in controlling the LAMPF-PSR Accelerator Complex at Los Alamos National Laboratory

    SciTech Connect

    Stuewe, R.; Schaller, S.; Bjorklund, E.; Burns, M.; Callaway, T.; Carr, G.; Cohen, S.; Kubicek, D.; Harrington, M.; Poore, R.; Schultz, D.

    1991-01-01

    Four interrelated projects are underway whose purpose is to migrate the LAMPF-PSR Accelerator Complex control systems to a system with a common set of hardware and software components. Project goals address problems in performance, maintenance and growth potential. Front-end hardware, operator interface hardware and software, computer systems, network systems and data system software are being simultaneously upgraded as part of these efforts. The efforts are being coordinated to provide for a smooth and timely migration to a client-sever model-based data acquisition and control system. An increased use of the distributed intelligence at both the front-end and operator interface is a key element of the projects. 2 refs., 2 figs.

  15. Accelerated acidification by inoculation with a microbial consortia in a complex open environment.

    PubMed

    Yu, Jiadong; Zhao, Ye; Liu, Bin; Zhao, Yubin; Wu, Jingwei; Yuan, Xufeng; Zhu, Wanbin; Cui, Zongjun

    2016-09-01

    Bioaugmentation using microbial consortia is helpful in some anaerobic digestion (AD) systems, but accelerated acidification to produce methane has not been performed effectively with corn stalks and cow dung. In this study, the thermophilic microbial consortia MC1 was inoculated into a complex open environment (unsterilized and sterilized systems) to evaluate the feasibility of bioaugmentation to improve acidification efficiency. The results indicated that MC1 itself degraded lignocellulose efficiently, and accumulated more organic acids within 3days. Similar trends were also observed in the unsterilized system, where the hemicellulose degradation rate and organic acid concentrations increased significantly by two-fold and 20.1% (P<0.05), respectively, and clearly reduced the loss of product. Microbial composition did not change obviously after inoculating MC1, but the abundance of members of MC1, such as Bacillus and Clostridium, increased clearly on day 3. Finally, the acidogenic fluid improved methane yield significantly (P<0.05) via bioaugmentation. PMID:27253477

  16. EFFICIENT COSMIC RAY ACCELERATION, HYDRODYNAMICS, AND SELF-CONSISTENT THERMAL X-RAY EMISSION APPLIED TO SUPERNOVA REMNANT RX J1713.7-3946

    SciTech Connect

    Ellison, Donald C.; Patnaude, Daniel J.; Slane, Patrick; Raymond, John

    2010-03-20

    We model the broadband emission from supernova remnant (SNR) RX J1713.7-3946 including, for the first time, a consistent calculation of thermal X-ray emission together with non-thermal emission in a nonlinear diffusive shock acceleration model. Our model tracks the evolution of the SNR including the plasma ionization state between the forward shock and the contact discontinuity. We use a plasma emissivity code to predict the thermal X-ray emission spectrum assuming the initially cold electrons are heated either by Coulomb collisions with the shock-heated protons (the slowest possible heating), or come into instant equilibration with the protons. For either electron heating model, electrons reach {approx}>10{sup 7} K rapidly and the X-ray line emission near 1 keV is more than 10 times as luminous as the underlying thermal bremsstrahlung continuum. Since recent Suzaku observations show no detectable line emission, this places strong constraints on the unshocked ambient medium density and on the relativistic electron-to-proton ratio. For the uniform circumstellar medium (CSM) models that we consider, the low densities and high relativistic electron-to-proton ratios required to match the Suzaku X-ray observations definitively rule out pion decay as the emission process producing GeV-TeV photons. We show that leptonic models, where inverse-Compton scattering against the cosmic background radiation dominates the GeV-TeV emission, produce better fits to the broadband thermal and non-thermal observations in a uniform CSM.

  17. Ternary complex consisting of DNA, polycation, and a natural polysaccharide of schizophyllan to induce cellular uptake by antigen presenting cells.

    PubMed

    Takeda, Yoichi; Shimada, Naohiko; Kaneko, Kenji; Shinkai, Seiji; Sakurai, Kazuo

    2007-04-01

    A natural polysaccharide called schizophyllan (SPG) can form a complex with polynucleotides, and the complex has been shown to deliver biofunctional short DNAs such as antisense DNAs and CpG-DNAs. Although it is a novel and efficient method, there is a drawback: attachment of homo-polynucleotide tails [for example, poly(dA) or poly(C)] to the end of DNA is necessary to stabilize the complex, because DNA heterosequences cannot bind to SPG. The aim of this paper is to present an alternative method in which SPG/DNA complexes can be made without using the tails. The basic strategy is as follows: since SPG can form hydrophobic domains in aqueous solutions, hydrophobic objects should be encapsulated by this domain. DNA alone is highly hydrophilic; however, once DNA/polycation complexes are made, they should be included by the SPG hydrophobic domain. The aim of this paper is to prove the formation of the polycation/DNA/SPG ternary complex. Gel electrophoresis showed that presence of SPG influenced the migration pattern of polycation+DNA mixtures. With increasing the SPG ratio, the zeta potential (zeta) of the polycation+DNA+SPG mixture decreased drastically to reach almost zeta = 0 and the particle size distributions were altered due to the ternary complex formation. Confocal laser scanning microscopy revealed that the polycation/DNA/SPG ternary complexes showed high uptake efficiency when the complexes were exposed to macrophage-like cells (J774.A1). IL-12 secretion was enhanced when CpG-DNA was added as the ternary complex. These features can be ascribed to the fact that J774.A1 has a SPG recognition site called Dectin-1 on the cellular surface and the ternary complex can be ingested by this pathway. PMID:17328571

  18. The Effects of Sex-Role Consistent and Inconsistent Information on the Social Perceptions of Complex, Noncomplex, Androgynous, and Sex-Typed Women.

    ERIC Educational Resources Information Center

    Capurso, Rose J.; Blocher, Donald H.

    1985-01-01

    Examined the effects of differences in cognitive complexity and sex-role orientation on the person perceptions formed by young college women (N=88) when presented with information varied in terms of consistency of sex-role appropriate behavior. Results indicated that complex subjects produced more differentiated final impressions than noncomplex…

  19. A consistent model for surface complexation on birnessite (-MnO2) and its application to a column experiment

    NASA Astrophysics Data System (ADS)

    Appelo, C. A. J.; Postma, D.

    1999-10-01

    Available surface complexation models for birnessite required the inclusion of bidentate bonds or the adsorption of cation-hydroxy complexes to account for experimentally observed H+/Mm+ exchange. These models contain inconsistencies and therefore the surface complexation on birnessite was re-examined. Structural data on birnessite indicate that sorption sites are located on three oxygens around a vacancy in the octahedral layer. The three oxygens together carry a charge of -2, i.e., constitute a doubly charged sorption site. Therefore a new surface complexation model was formulated using a doubly charged, diprotic, sorption site where divalent cations adsorbing via inner-sphere complexes bind to the three oxygens. Using the diprotic site concept we have remodeled the experimental data for sorption on birnessite by Murray (1975) using the surface complexation model of Dzombak and Morel (1990). Intrinsic constants for the surface complexation model were obtained with the non-linear optimization program PEST in combination with a modified version of PHREEQC (Parkhurst, 1995). The optimized model was subsequently tested against independent data sets for synthetic birnessite by Balistrieri and Murray (1982) and Wang et al. (1996). It was found to describe the experimental data well. Finally the model was tested against the results of column experiments where cations adsorbed on natural MnO2 coated sand. In this case as well, the diprotic surface complexation model gave an excellent description of the experimental results.

  20. Chitosan oligosaccharide-Ca complex accelerates the depuration of cadmium from Chlamys ferrari

    NASA Astrophysics Data System (ADS)

    Huang, Guoqing; Sun, Jipeng; Wang, Dongfeng; Xu, Ying; Xu, Wei

    2012-06-01

    This study investigated the effect of a chitosan oligosaccharide-Ca complex (COS-Ca) on the depuration of cadmium (Cd) from Chlamys ferrari. After exposure to 0.5 mg L-1 CdCl2 for 3 or 7 d, the scallops were treated by COS-Ca prior to determination of Cd, calcium (Ca) and zinc (Zn) contents, Cd distribution in organs, malondialdehyde (MDA) content and antioxidant variables. Results showed that COS-Ca reduced Cd content in the viscera of the scallops, with highest Cd depuration rate (47%) observed on day 3. The COS-Ca concentration substantially affected Cd depuration, and the exposure to 8.75 mg L-1 COS-Ca led to significantly higher Cd depuration rate compared with those of lower COS-Ca concentrations (1.75, 3.5, 5.25, and 7.00 mg L-1). Distribution analysis of Cd in scallop organs indicated that COS-Ca significantly reduced Cd content in the kidney throughout the 5-d experiment, as well as in the gill during the early stage of Cd depuration. In addition, COS-Ca treatment decreased glutathione peroxidase (GSH-Px) activity and MDA content while increasing superoxide dismutase (SOD) and catalase (CAT) activities on different days. Our work suggested COS-Ca complex treatment as an effective method for acceleration of Cd depuration from Cd-contaminated bivalves.

  1. A Complex of Htm1 and the Oxidoreductase Pdi1 Accelerates Degradation of Misfolded Glycoproteins.

    PubMed

    Pfeiffer, Anett; Stephanowitz, Heike; Krause, Eberhard; Volkwein, Corinna; Hirsch, Christian; Jarosch, Ernst; Sommer, Thomas

    2016-06-01

    A quality control system in the endoplasmic reticulum (ER) efficiently discriminates polypeptides that are in the process of productive folding from conformers that are trapped in an aberrant state. Only the latter are transported into the cytoplasm and degraded in a process termed ER-associated protein degradation (ERAD). In the ER, an enzymatic cascade generates a specific N-glycan structure of seven mannosyl and two N-acetylglucosamine residues (Man7GlcNAc2) on misfolded glycoproteins to facilitate their disposal. We show that a complex encompassing the yeast lectin-like protein Htm1 and the oxidoreductase Pdi1 converts Man8GlcNAc2 on glycoproteins into the Man7GlcNAc2 signal. In vitro the Htm1-Pdi1 complex processes both unfolded and native proteins albeit with a preference for the former. In vivo, elevated expression of HTM1 causes glycan trimming on misfolded and folded proteins, but only degradation of the non-native species is accelerated. Thus, modification with a Man7GlcNAc2 structure does not inevitably commit a protein for ER-associated protein degradation. The function of Htm1 in ERAD relies on its association with Pdi1, which appears to regulate the access to substrates. Our data support a model in which the balanced activities of Pdi1 and Htm1 are crucial determinants for the efficient removal of misfolded secretory glycoproteins. PMID:27053108

  2. Finite difference method accelerated with sparse solvers for structural analysis of the metal-organic complexes

    NASA Astrophysics Data System (ADS)

    Guda, A. A.; Guda, S. A.; Soldatov, M. A.; Lomachenko, K. A.; Bugaev, A. L.; Lamberti, C.; Gawelda, W.; Bressler, C.; Smolentsev, G.; Soldatov, A. V.; Joly, Y.

    2016-05-01

    Finite difference method (FDM) implemented in the FDMNES software [Phys. Rev. B, 2001, 63, 125120] was revised. Thorough analysis shows, that the calculated diagonal in the FDM matrix consists of about 96% zero elements. Thus a sparse solver would be more suitable for the problem instead of traditional Gaussian elimination for the diagonal neighbourhood. We have tried several iterative sparse solvers and the direct one MUMPS solver with METIS ordering turned out to be the best. Compared to the Gaussian solver present method is up to 40 times faster and allows XANES simulations for complex systems already on personal computers. We show applicability of the software for metal-organic [Fe(bpy)3]2+ complex both for low spin and high spin states populated after laser excitation.

  3. Uniform Plasma Etching of Complex Shaped Three Dimensional Niobium Structures for Particle Accelerators

    NASA Astrophysics Data System (ADS)

    Upadhyay, Janardan; Im, Do; Peshl, Jeremy; Popovic, Svetozar; Vuskovic, Lepsha; Phillips, Larry; Valente-Felliciano, Anne-Marie

    2014-10-01

    Complex shaped three dimensional niobium structures are used in particle accelerators as super conducting radio frequency (SRF) cavities. The inner surfaces of these structures have to be chemically etched for better performance, as SRF performance parameters are very sensitive to their properties. Plasma etching of inner surface of three dimensional niobium structures has not been reported even though plasma etching of niobium has been reported earlier for Josephson junction and other applications. We are proposing an RF capacitively coupled coaxial (ccp) plasma etching method for nano machining of niobium structures for SRF applications. We are using gas mixture of Argon and Chlorine. We report the effects of the pressure, RF power, gas concentration, shape and size of the inner electrode, temperature of the structure, DC bias voltage and residence time on the etch rate of the niobium. We also show the method to reduce the asymmetry effect in coaxial ccp by changing the shape of the inner electrode in cylindrical structure, as well as a method to overcome the severe loading effect in etching of 3D structures for uniform mass removal purpose. Supported by DOE under Grant No. DE-SC0007879. J.U. acknowledges support by JSA/DOE via DE-AC05-06OR23177.

  4. A new slip stacking RF system for a twofold power upgrade of Fermilab's Accelerator Complex

    SciTech Connect

    Madrak, Robyn

    2014-09-11

    Fermilab@?s Accelerator Complex has been recently upgraded, in order to increase the 120GeV proton beam power on target from about 400kW to over 700kW for NO@nA and other future intensity frontier experiments. One of the key ingredients of the upgrade is the offloading of some Main Injector synchrotron operations - beam injection and RF manipulation called ''slip stacking'' - to the 8GeV Recycler Ring, which had until recently been used only for low-intensity antiproton storage and cooling. This required construction of two new 53MHz RF systems for the slip-stacking manipulations. The cavities operate simultaneously at V_p_e_a_k@?150kV, but at slightly different frequencies (@Df=1260Hz). Their installation was completed in September 2013. This paper describes the novel solutions used in the design of the new cavities, their tuning system, and the associated high power RF system. First results showing effective operation of the RF system, beam capture and successful slip-stacking in the Recycler Ring are presented.

  5. Mitochondrial Complex I Deficiency Increases Protein Acetylation and Accelerates Heart Failure

    PubMed Central

    Karamanlidis, Georgios; Lee, Chi Fung; Garcia-Menendez, Lorena; Kolwicz, Stephen C.; Suthammarak, Wichit; Gong, Guohua; Sedensky, Margaret M.; Morgan, Philip G.; Wang, Wang; Tian, Rong

    2013-01-01

    Summary Mitochondrial respiratory dysfunction is linked to the pathogenesis of multiple diseases including heart failure but the specific mechanisms for this link remain largely elusive. We modeled the impairment of mitochondrial respiration by inactivation of the Ndufs4 gene, a protein critical for Complex I (C-I) assembly, in the mouse heart (cKO). While C-I supported respiration decreased by >40%, the cKO mice maintained normal cardiac function in vivo and high-energy phosphate content in isolated perfused hearts. However, the cKO mice developed accelerated heart failure after pressure overload or repeated pregnancy. Decreased NAD+/NADH ratio by C-I deficiency inhibited Sirt3 activity, leading to increase in protein acetylation, and sensitization of the permeability transition in mitochondria (mPTP). NAD+ precursor supplementation to cKO mice partially normalized the NAD+/NADH ratio, protein acetylation and mPTP sensitivity. These findings describe a mechanism connecting mitochondrial dysfunction to the susceptibility to diseases and propose a potential therapeutic target. PMID:23931755

  6. Multi-core CPU or GPU-accelerated Multiscale Modeling for Biomolecular Complexes

    PubMed Central

    Liao, Tao; Zhang, Yongjie; Kekenes-Huskey, Peter M.; Cheng, Yuhui; Michailova, Anushka; McCulloch, Andrew D.; Holst, Michael; McCammon, J. Andrew

    2013-01-01

    Multi-scale modeling plays an important role in understanding the structure and biological functionalities of large biomolecular complexes. In this paper, we present an efficient computational framework to construct multi-scale models from atomic resolution data in the Protein Data Bank (PDB), which is accelerated by multi-core CPU and programmable Graphics Processing Units (GPU). A multi-level summation of Gaus-sian kernel functions is employed to generate implicit models for biomolecules. The coefficients in the summation are designed as functions of the structure indices, which specify the structures at a certain level and enable a local resolution control on the biomolecular surface. A method called neighboring search is adopted to locate the grid points close to the expected biomolecular surface, and reduce the number of grids to be analyzed. For a specific grid point, a KD-tree or bounding volume hierarchy is applied to search for the atoms contributing to its density computation, and faraway atoms are ignored due to the decay of Gaussian kernel functions. In addition to density map construction, three modes are also employed and compared during mesh generation and quality improvement to generate high quality tetrahedral meshes: CPU sequential, multi-core CPU parallel and GPU parallel. We have applied our algorithm to several large proteins and obtained good results. PMID:24352481

  7. New Models of Solar Wind Acceleration and Stream Interactions in the Sun's Topologically Complex Magnetic Field

    NASA Astrophysics Data System (ADS)

    Cranmer, S. R.; Van Ballegooijen, A. A.; Woolsey, L. N.

    2012-12-01

    The last decade has seen significant progress toward identifying and characterizing the processes that heat the corona and accelerate the solar wind. It is believed that the low-speed solar wind comes from a wide range of source regions in the corona, including streamers, pseudostreamers, active regions, and small coronal holes. These source regions tend to be associated with the most topologically complex magnetic fields, and it is unclear how the coronal field lines connect to the large-scale open heliospheric field. To learn more about these connections, we present new models of turbulence-driven coronal heating and solar wind acceleration along empirically constrained field lines. To begin, we chose a time period during which the footpoints linked to the ecliptic plane were rooted in Quiet Sun (QS) regions away from both large coronal holes and strong-field active regions. The weak and mixed-polarity QS field was observed at high resolution by the VSM instrument of SOLIS, and we extrapolated this field into the corona using the potential field source surface method. Time-steady 1D models of individual flux tubes were created with the ZEPHYR code (Cranmer et al. 2007) that solves the one-fluid equations of mass, momentum, and energy conservation from the photosphere to 4 AU. Then, to take account of stream-stream interactions between the flux tubes, we solved a 2D time-steady set of MHD conservation equations to determine the corotating longitudinal structure in the ecliptic plane. We aim to understand the extent to which fine-scale inter-tube plasma structures in the corona survive to large distances. In other words, we want to know how much of the coronal flux tube "spaghetti" is either shredded by turbulence or smeared out by stream interactions. We also plan to evaluate the level of high-resolution detail that is needed in coronal flux tube modeling in order to accurately predict the space weather consequences of various kinds of corotating structures in the

  8. Interesting experimental results in Japan Proton Accelerator Research Complex H- ion-source development (invited).

    PubMed

    Ueno, A; Oguri, H; Ikegami, K; Namekawa, Y; Ohkoshi, K

    2010-02-01

    The following interesting experimental results observed in Japan Proton Accelerator Research Complex (J-PARC) H(-) ion-source developments are reviewed. It was proven that almost all of H(-) ions were produced with surface reactions in cesium (Cs)-free J-PARC H(-) ion-sources. The world's most intense class H(-) ion current of 38 mA in Cs-free ion sources for a high-energy linac was attained by an optimal shape and high temperature of the plasma electrode (PE), usage of a lanthanum hexaboride (LaB(6)) filament, and a newly devised high-power constant-current pulsed-arc power supply indispensable for it. It was also proven that the H(-) ion current could be increased to more than 40 mA by optimizing LaB(6)-filament shape. The surface elemental analysis of the PE after operation with a LaB(6)-filament showed that it was coated by boron (B) 95.5%, lanthanum (La) 2.5%, and oxygen (O) 1.9%. The H(-) ion current decreased by about 20% when a tungsten (W) filament was used instead of a LaB(6)-filament. The H(-) ion current could not be increased by seeding cesium (Cs) if the LaB(6)-filament was used. On the other hand, it was increased to more than 70 mA with much lower arc current of 150 A if Cs was seeded when a W-filament was used. PMID:20192389

  9. Sulphasalazine accelerates apoptosis in neutrophils exposed to immune complex: Role of caspase pathway.

    PubMed

    Bertolotto, M; Dallegri, F; Dapino, P; Quercioli, A; Pende, A; Ottonello, L; Montecucco, Fabrizio

    2009-11-01

    1. Neutrophils release several histotoxic molecules that cause tissue injury. Neutrophil apoptosis is a crucial process that governs the persistence of inflammatory disorders and tissue damage. Thus, in the present study, we investigated whether the anti-inflammatory drug sulphasalazine (SSZ) affects neutrophil apoptosis in the presence of insoluble immune complex (IC). 2. Neutrophils were obtained from healthy donors. Neutrophils were resuspended in incubation medium and incubated for 2-12 h with or without 10, 30 or 100 micromol/L SSZ and 25 microg/mL IC. In some experiments, cells were co-incubated with 20 micromol/L Z-IETD-fmk (a caspase 8 inhibitor) or 20 micromol/L Z-LEHD-fmk (a caspase 9 inhibitor). Apoptosis was evaluated morphologically on cytological preparations stained with May-Grünwald-Giemsa as well as by flow cytometry analysis of annexin V and propidium iodide staining. Caspase 3 activity was determined spectrophotometrically. 3. At 100 micromol/L, SSZ significantly accelerated IC-induced neutrophil apoptosis. Treatment of neutrophils with 20 micromol/L of the caspase 8 or 9 inhibitors Z-IETD-fmk or Z-LEHD-fmk, respectively, demonstrated that the SSZ-induced pro-apoptotic effect was mediated by a caspase 8- but not caspase 9-dependent pathway. The caspase 3 activity assay showed that treatment with 100 micromol/L SSZ increased caspase 3 activation. 4. In conclusion, the results of the present study indicate that it is possible that the molecular mechanism underlying SSZ protection against neutrophil-mediated tissue injury inflammatory disorders, such as rheumatoid arthritis and inflammatory bowel diseases, involves a caspase 8-dependent pathway. PMID:19473188

  10. Cytosolic phospholipase A2 shows burst kinetics consistent with the slow, reversible formation of a dead-end complex.

    PubMed

    Guenther, Matthew G; Witmer, Mark R; Burke, James R

    2002-02-01

    Cytosolic phospholipase A2 catalyzes the hydrolysis of the sn-2 ester of arachidonate-containing phospholipids. In the present research, a "burst" of arachidonate which precedes a somewhat slower, linear rate (upsilon) of product formation was observed and characterized using covesicles of 1,2-dimyristoyl-sn-glycero-3-phosphomethanol (DMPM) containing <10 mol% 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine as substrate. The magnitude of the burst (pi) was enzyme dependent, in both the presence and absence of glycerol. Upon subsequent addition of enzyme after the primary burst was complete, a second burst of arachidonate production was observed. This is consistent with the effect resulting from an enzyme effect and not from changes in the substrate. The use of 1,2-dioleoyl-sn-glycero-3-phosphomethanol as the carrier phospholipid instead of DMPM greatly reduced the rate of hydrolysis without a large effect on the pi/upsilon ratio, consistent with the burst not being the result of limitations in the lateral diffusion rate of phospholipids within the covesicles. When the assay is performed in the presence of glycerol, the burst phenomenon was also observed with the monoarachidonoyl glycerol transacylase product which shows that the effect occurs through a common mechanism. The burst and subsequent linear rate of hydrolysis are highly temperature dependent, with a pronounced increase in the pi/upsilon ratio as the temperature is increased from 35 to 45 degrees C. A mechanism in which a slow equilibrium between an active and less active (inactive) state of substrate-bound enzyme is proposed. This may provide a means by which the enzyme is switched off after a few hundred turnovers in order to prevent unabated phospholipid hydrolysis in cells which may be deleterious to membrane integrity. PMID:11811954

  11. The impact of job complexity and performance measurement on the temporal consistency, stability, and test-retest reliability of employee job performance ratings.

    PubMed

    Sturman, Michael C; Cheramie, Robin A; Cashen, Luke H

    2005-03-01

    Although research has shown that individual job performance changes over time, the extent of such changes is unknown. In this article, the authors define and distinguish between the concepts of temporal consistency, stability, and test-retest reliability when considering individual job performance ratings over time. Furthermore, the authors examine measurement type (i.e., subjective and objective measures) and job complexity in relation to temporal consistency, stability, and test-retest reliability. On the basis of meta-analytic results, the authors found that the test-retest reliability of these ratings ranged from .83 for subjective measures in low-complexity jobs to .50 for objective measures in high-complexity jobs. The stability of these ratings over a 1-year time lag ranged from .85 to .67. The analyses also reveal that correlations between performance measures decreased as the time interval between performance measurements increased, but the estimates approached values greater than zero. PMID:15769237

  12. A temporal analysis shows major histocompatibility complex loci in the Scandinavian wolf population are consistent with neutral evolution.

    PubMed

    Seddon, J M; Ellegren, H

    2004-11-01

    The major histocompatibility complex (MHC) has an integral role in the immune system, and hence diversity at its genes may be of particular importance for the health of populations. In large populations, balancing selection maintains diversity in MHC genes, but theoretical expectations indicate that this form of selection is absent or inefficient in small populations. We examine the level of diversity at three MHC class II loci in the wolf population of Scandinavia, a population naturally recolonized with a genetic contribution from as few as three founders, and in four neighbouring wolf populations. In the Scandinavian wolf population, two alleles were found for each locus and the distribution of alleles is compatible with their linkage into two haplotypes. Changes in the level of heterozygosity over time since recolonization demonstrate the effects of the proposed arrival of an immigrant wolf. The maintenance of diversity is shown to be compatible with a neutral, random allocation of alleles, in conjunction with crossing between packs. A total of 15 DRB1, seven DQA and 10 DQB1 alleles are found in four neighbouring wolf populations, with substantial sharing across populations. Even in these larger populations, bottlenecks and fragmentation with consequent genetic drift are likely to have resulted in few indicators for balancing selection and significant differentiation of populations. PMID:15539354

  13. STOCHASTIC ACCELERATION AND THE EVOLUTION OF SPECTRAL DISTRIBUTIONS IN SYNCHRO-SELF-COMPTON SOURCES: A SELF-CONSISTENT MODELING OF BLAZARS' FLARES

    SciTech Connect

    Tramacere, A.; Taylor, A. M.; Massaro, E.

    2011-10-01

    The broadband spectral distributions of non-thermal sources, such as those of several known blazars, are well described by a log-parabolic fit. The second-degree term in these fits measures the curvature in the spectrum. In this paper, we investigate whether the curvature parameter observed in the spectra of the synchrotron emission can be used as a fingerprint of stochastic acceleration. As a first approach, we use the multiplicative central limit theorem to show how fluctuations in the energy gain result in the broadening of the spectral shape, introducing a curvature into the energy distribution. Then, by means of a Monte Carlo description, we investigate how the curvature produced in the electron distribution is linked to the diffusion in momentum space. To get a more generic description of the problem we turn to the diffusion equation in momentum space. We first study some 'standard' scenarios, in order to understand the conditions that make the curvature in the spectra significant, and the relevance of cooling during the acceleration process. We try to quantify the correlation between the curvature and the diffusive process in the pre-equilibrium stage, and investigate how the transition between the Klein-Nishina and the Thomson regimes, in inverse Compton cooling, determine the curvature in the distribution at equilibrium. We apply these results to some observed trends, such as the anticorrelation between the peak energy and the curvature term observed in the spectra of Mrk 421, and a sample of BL Lac objects whose synchrotron emission peaks at X-ray energies.

  14. Prototype of a test bench for applied research on Extracted beams of the nuclotron accelerator complex

    NASA Astrophysics Data System (ADS)

    Baldin, A. A.; Berlev, A. I.; Bradnova, V.; Butenko, A. V.; Fedorov, A. N.; Kudashkin, I. V.

    2016-05-01

    The results of the development and testing of elements of a test bench for investigating the impact of accelerated particle beams on biological objects, electronics, and other targets are presented. The systems for beam monitoring and target positioning were tested on extracted argon beams in the framework of experiments on studying the radiation hardness of electronic components.

  15. Self-Consistent Simulation of Transport and Energy Deposition of Intense Laser-Accelerated Proton Beams in Solid-Density Matter

    NASA Astrophysics Data System (ADS)

    Kim, J.; Qiao, B.; McGuffey, C.; Wei, M. S.; Grabowski, P. E.; Beg, F. N.

    2015-07-01

    The first self-consistent hybrid particle-in-cell (PIC) simulation of intense proton beam transport and energy deposition in solid-density matter is presented. Both the individual proton slowing-down and the collective beam-plasma interaction effects are taken into account with a new dynamic proton stopping power module that has been added to a hybrid PIC code. In this module, the target local stopping power can be updated at each time step based on its thermodynamic state. For intense proton beams, the reduction of target stopping power from the cold condition due to continuous proton heating eventually leads to broadening of the particle range and energy deposition far beyond the Bragg peak. For tightly focused beams, large magnetic field growth in collective interactions results in self-focusing of the beam and much stronger localized heating of the target.

  16. Structural Basis of Rev1-mediated Assembly of a Quaternary Vertebrate Translesion Polymerase Complex Consisting of Rev1, Heterodimeric Polymerase (Pol) ζ, and Pol κ*

    PubMed Central

    Wojtaszek, Jessica; Lee, Chul-Jin; D'Souza, Sanjay; Minesinger, Brenda; Kim, Hyungjin; D'Andrea, Alan D.; Walker, Graham C.; Zhou, Pei

    2012-01-01

    DNA synthesis across lesions during genomic replication requires concerted actions of specialized DNA polymerases in a potentially mutagenic process known as translesion synthesis. Current models suggest that translesion synthesis in mammalian cells is achieved in two sequential steps, with a Y-family DNA polymerase (κ, η, ι, or Rev1) inserting a nucleotide opposite the lesion and with the heterodimeric B-family polymerase ζ, consisting of the catalytic Rev3 subunit and the accessory Rev7 subunit, replacing the insertion polymerase to carry out primer extension past the lesion. Effective translesion synthesis in vertebrates requires the scaffolding function of the C-terminal domain (CTD) of Rev1 that interacts with the Rev1-interacting region of polymerases κ, η, and ι and with the Rev7 subunit of polymerase ζ. We report the purification and structure determination of a quaternary translesion polymerase complex consisting of the Rev1 CTD, the heterodimeric Pol ζ complex, and the Pol κ Rev1-interacting region. Yeast two-hybrid assays were employed to identify important interface residues of the translesion polymerase complex. The structural elucidation of such a quaternary translesion polymerase complex encompassing both insertion and extension polymerases bridged by the Rev1 CTD provides the first molecular explanation of the essential scaffolding function of Rev1 and highlights the Rev1 CTD as a promising target for developing novel cancer therapeutics to suppress translesion synthesis. Our studies support the notion that vertebrate insertion and extension polymerases could structurally cooperate within a megatranslesion polymerase complex (translesionsome) nucleated by Rev1 to achieve efficient lesion bypass without incurring an additional switching mechanism. PMID:22859295

  17. Acceleration of thrombin-antithrombin complex formation in rat hindquarters via heparinlike molecules bound to the endothelium.

    PubMed Central

    Marcum, J A; McKenney, J B; Rosenberg, R D

    1984-01-01

    We have examined the role of heparinlike molecules in the regulation of coagulation by perfusing rat hindquarters with purified human thrombin and with its plasma inhibitor, antithrombin. Our data indicate that contact of the hemostatic components with the endothelium enhances the rate of thrombin-antithrombin complex formation by as much as 19-fold over the uncatalyzed rate of enzyme-inhibitor interaction. Heparinlike molecules are responsible for the antithrombin accelerating activity. The amount of thrombin-antithrombin complex generated within the hindlimb preparation after pretreatment of the vasculature with purified Flavobacterium heparinase or with addition of platelet Factor IV to the hemostatic components, was equal to the uncatalyzed levels. These heparinlike molecules appear to be tightly bound to the luminal surface of the endothelium, since they could not be detected within the physiologic buffer that was perfused through the animal. The above mucopolysaccharides function in a manner similar to commercial heparin, since modification of antithrombin at a site critical for heparin-dependent acceleration of the protease inhibitor resulted in a level of interaction product identical to the uncatalyzed amount. Finally, addition of diisofluorophosphate-thrombin to the enzyme perfusion stream reduced the amount of thrombin-antithrombin complex formed in the animal by 30-40%, which suggested that thrombin bound to the endothelium as well as enzyme free in solution are accessible to antithrombin that has interacted with heparinlike molecules present on the endothelium. PMID:6746897

  18. Highly asymmetric bromocyclization of tryptophol: unexpected accelerating effect of DABCO-derived bromine complex.

    PubMed

    Liu, Huan; Jiang, Guangde; Pan, Xixian; Wan, Xiaolong; Lai, Yisheng; Ma, Dawei; Xie, Weiqing

    2014-04-01

    Highly asymmetric bromocyclization of tryptophol by using chiral anionic phase-transfer catalyst and DABCO-derived brominating reagent is described. Optimization of the reaction conditions revealed that the reaction rate was accelerated together with improvement of enantioselectivity by addition of catalytic DABCO-derived brominating reagent. From tryptophol, 3-bromofuroindoline could be directly obtained in excellent enantioselectivities by employing this novel methodology. PMID:24666363

  19. Proton transport pathways in an acid-base complex consisting of a phosphonic acid group and a 1,2,3-triazolyl group.

    PubMed

    Yue, Baohua; Yan, Liuming; Han, Shuaiyuan; Xie, Liqing

    2013-07-01

    The proton transport pathways in an acid-base complex consisting of a phosphonic acid group and a 1,2,3-triazolyl group were studied using density functional theory (DFT) calculations in terms of stable configurations and transition states of the molecular or ionic dimers and trimers and verified by proof-of-concept experiments including experimental measurements of overall conductivity and (1)H NMR and FTIR spectroscopy of the methylphosphonic acid (MPA) and 1,2,3-triazole (Tri) complex as well as overall proton conductivity of polymeric blend of poly(vinylphosphonic acid) (PVPA) and poly(4-vinyl-1H-1,2,3-triazole) (PVTri). From the DFT calculations of dimers and trimers composed of ethylphosphonic acid (EPA), Tri, and their deprotonated counterparts, it was concluded that the intermolecular hydrogen bonds of the transition states corresponding to proton transport are much shorter than those of stable configurations, but the O-H and N-H bonds are much longer than those of stable configurations. The tautomerization activation energy decreases from 0.927-1.176 eV in Tri-Tri dimers to 0.336-0.444 eV in the EPA-Tri dimers. From the proof-of-concept experiments, about a 50 fold increase in overall conductivity was observed in the MPA-Tri complex consisting of 10% (molar ratio) MPA compared to pure Tri, and the calculated activation energy is consistent with the experimental activation energy evaluated from temperature dependence of proton conductivity of pure Tri and the MPA-Tri complex. In addition, the fast proton exchange between MPA and Tri, consistent with the DFT calculations, was verified by (1)H NMR and FTIR spectroscopy. Finally, a polymeric blend of PVPA and PVTri was prepared, and its proton conductivity at about 2.1 mS·cm(-1) in anhydrous state at 100 °C was observed to be significantly higher than that of PVPA or of poly(VPA-co-1-vinyl-1,2,4-triazole). The proton conductivity of the polymeric PVPA and PVTri blend in humidity state is in the same range as

  20. Tsallis entropy and complexity theory in the understanding of physics of precursory accelerating seismicity.

    NASA Astrophysics Data System (ADS)

    Vallianatos, Filippos; Chatzopoulos, George

    2014-05-01

    Strong observational indications support the hypothesis that many large earthquakes are preceded by accelerating seismic release rates which described by a power law time to failure relation. In the present work, a unified theoretical framework is discussed based on the ideas of non-extensive statistical physics along with fundamental principles of physics such as the energy conservation in a faulted crustal volume undergoing stress loading. We derive the time-to-failure power-law of: a) cumulative number of earthquakes, b) cumulative Benioff strain and c) cumulative energy released in a fault system that obeys a hierarchical distribution law extracted from Tsallis entropy. Considering the analytic conditions near the time of failure, we derive from first principles the time-to-failure power-law and show that a common critical exponent m(q) exists, which is a function of the non-extensive entropic parameter q. We conclude that the cumulative precursory parameters are function of the energy supplied to the system and the size of the precursory volume. In addition the q-exponential distribution which describes the fault system is a crucial factor on the appearance of power-law acceleration in the seismicity. Our results based on Tsallis entropy and the energy conservation gives a new view on the empirical laws derived by other researchers. Examples and applications of this technique to observations of accelerating seismicity will also be presented and discussed. This work was implemented through the project IMPACT-ARC in the framework of action "ARCHIMEDES III-Support of Research Teams at TEI of Crete" (MIS380353) of the Operational Program "Education and Lifelong Learning" and is co-financed by the European Union (European Social Fund) and Greek national funds

  1. Accelerating the Association of the Most Stable Protein-Ligand Complex by More than Two Orders of Magnitude.

    PubMed

    Giese, Christoph; Eras, Jonathan; Kern, Anne; Schärer, Martin A; Capitani, Guido; Glockshuber, Rudi

    2016-08-01

    The complex between the bacterial type 1 pilus subunit FimG and the peptide corresponding to the N-terminal extension (termed donor strand, Ds) of the partner subunit FimF (DsF) shows the strongest reported noncovalent molecular interaction, with a dissociation constant (KD ) of 1.5×10(-20)  m. However, the complex only exhibits a slow association rate of 330 m(-1)  s(-1) that limits technical applications, such as its use in affinity purification. Herein, a structure-based approach was used to design pairs of FimGt (a FimG variant lacking its own N-terminal extension) and DsF variants with enhanced electrostatic surface complementarity. Association of the best mutant FimGt/DsF pairs was accelerated by more than two orders of magnitude, while the dissociation rates and 3D structures of the improved complexes remained essentially unperturbed. A KD  value of 8.8×10(-22)  m was obtained for the best mutant complex, which is the lowest value reported to date for a protein/ligand complex. PMID:27351462

  2. Self-Reported Responses to Player Profile Questions Show Consistency with the Use of Complex Attentional Strategies by Expert Horseshoe Pitchers

    PubMed Central

    Fairbrother, Jeffrey T.; Post, Phillip G.; Whalen, Sam J.

    2016-01-01

    The advantages on an external focus of attention have been demonstrated for a variety of sport tasks. The constrained action hypothesis (Wulf et al., 2001) argues that focusing externally on the movement effect results in the use of automated processes for movement control. In contrast, focusing internally in an attempt to control the movements of the body disrupts normally automated processes and degrades performance. Research on experts, however, suggests that they may adopt more complex attentional strategies. The present study provided a unique opportunity to examine expert horseshoe players’ attentional strategies as indicated by their self-reported responses to questions included in a National Horseshoe Pitchers Association (NHPA) player profile questionnaire. Responses submitted by 83 top NHPA players were examined to determine the frequency of references to the use of internal and external focus points and identify categories related to attentional strategies. Results indicated that the large majority of players reported using focus points that are consistent with an external focus of attention and that their thoughts corresponded to one or more categories related to technique, mental focus or concentration, general success, use of external focus cues, and emotional control. The findings are consistent with the view that experts may adopt complex attentional strategies that encompass both an external focus and thoughts about a variety of other performance related factors. PMID:27458419

  3. Transonic Navier-Stokes solutions about a complex high-speed accelerator configuration

    NASA Technical Reports Server (NTRS)

    Ghaffari, Farhad; Bates, Brent L.; Luckring, James M.; Thomas, James L.

    1990-01-01

    Three-dimensional transonic viscous flow computations are presented for a generic high-speed accelerator model which includes wing, body, fillets, and a no-flow through engine nacelle. Solutions are obtained from an algorithm for the compressible Navier-Stokes equations which incorporates an upwind-biased, flux-vector-splitting approach along with longitudinally-patched grids. Results are presented for fully turbulent flow assumptions and include correlations with wind tunnel data. A good quantitative agreement for the forebody surface pressure distribution is achieved between computations and the available wind-tunnel measurements at freestream Mach number equal to 0.9. Furthermore, it is demonstrated that the flow is stagnating around the boattail region due to separation from the aft-engine cowl lip.

  4. Using Narrative Intervention to Accelerate Canonical Story Grammar and Complex Language Growth in Culturally Diverse Preschoolers

    ERIC Educational Resources Information Center

    Petersen, Douglas B.; Spencer, Trina D.

    2016-01-01

    Oral narratives are a commonly used, meaningful means of communication that reflects academic language. New state curriculum standards include narrative-related language expectations for young school-age children, including story grammar and complex language. This article provides a review of preschool narrative-based language intervention…

  5. A workflow for transferring heterogeneous complex geological models to consistent finite element models and application to a deep geothermal reservoir operation

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Bauer, Sebastian

    2016-04-01

    Geological models are the prerequisite of exploring possible use of the subsurface and evaluating induced impacts. Subsurface geological models often show strong complexity in geometry and hydraulic connectivity because of their heterogeneous nature. In order to model that complexity, the corner point grid approach has been applied by geologists for decades. The corner point grid utilizes a set of hexahedral blocks to represent geological formations. Due to the appearance of eroded geological layers, some edges of those blocks may be collapsed and the blocks thus degenerate. This leads to the inconsistency and the impossibility of using the corner point grid directly with a finite element based simulator. Therefore, in this study, we introduce a workflow for transferring heterogeneous geological models to consistent finite element models. In the corner point grid, the hexahedral blocks without collapsed edges are converted to hexahedral elements directly. But if they degenerate, each block is divided into prism, pyramid and tetrahedral elements based on individual degenerated situation. This approach consistently converts any degenerated corner point grid to a consistent hybrid finite element mesh. Along with the above converting scheme, the corresponding heterogeneous geological data, e.g. permeability and porosity, can be transferred as well. Moreover, well trajectories designed in the corner point grid can be resampled to the nodes in the finite element mesh, which represents the location for source terms along the well path. As a proof of concept, we implement the workflow in the framework of transferring models from Petrel to the finite element OpenGeoSys simulator. As application scenario we choose a deep geothermal reservoir operation in the North German Basin. A well doublet is defined in a saline aquifer in the Rhaetian formation, which has a depth of roughly 4000 m. The geometric model shows all kinds of degenerated blocks due to eroded layers and the

  6. HDF5-FastQuery: Accelerating Complex Queries on HDF Datasets usingFast Bitmap Indices

    SciTech Connect

    Gosink, Luke; Shalf, John; Stockinger, Kurt; Wu, Kesheng; Bethel,Wes

    2006-03-30

    Large scale scientific data is often stored in scientific data formats such as FITS, netCDF and HDF. These storage formats are of particular interest to the scientific user community since they provide multi-dimensional storage and retrieval. However, one of the drawbacks of these storage formats is that they do not support semantic indexing which is important for interactive data analysis where scientists look for features of interests such as ''Find all supernova explosions where energy > 10{sup 5} and temperature > 10{sup 6}''. In this paper we present a novel approach called HDF5-FastQuery to accelerate the data access of large HDF5 files by introducing multi-dimensional semantic indexing. Our implementation leverages an efficient indexing technology called bitmap indexing that has been widely used in the database community. Bitmap indices are especially well suited for interactive exploration of large-scale read only data. Storing the bitmap indices into the HDF5 file has the following advantages: (a) Significant performance speedup of accessing subsets of multi-dimensional data and (b) portability of the indices across multiple computer platforms. We will present an API that simplifies the execution of queries on HDF5 files for general scientific applications and data analysis. The design is flexible enough to accommodate the use of arbitrary indexing technology for semantic range queries. We will also provide a detailed performance analysis of HDF5-FastQuery for both synthetic and scientific data. The results demonstrate that our proposed approach for multi-dimensional queries is up to a factor of 2 faster than HDF5.

  7. HDF5-FastQuery: Accelerating Complex Queries on HDF Datasets UsingFast Bitmap Indices

    SciTech Connect

    Gosink, Luke; Shalf, John; Stockinger, Kurt; Wu, Kesheng; Bethel,Wes

    2005-12-07

    Large scale scientific data is often stored in scientific data formats such as FITS, netCDF and HDF. These storage formats are of particular interest to the scientific user community since they provide multi-dimensional storage and retrieval. However, one of the drawbacks of these storage formats is that they do not support semantic indexing which is important for interactive data analysis where scientists look for features of interests such as ''Find all supernova explosions where energy >105 and temperature >106''. In this paper we present a novel approach called HDF5-FastQuery to accelerate the data access of large HDF5 files by introducing multi-dimensional semantic indexing. Our implementation leverages an efficient indexing technology called ''bitmapindexing'' that has been widely used in the database community. Bitmapindices are especially well suited for interactive exploration of large-scale read-only data. Storing the bitmap indices into the HDF5 file has the following advantages: (a) Significant performance speedup of accessing subsets of multi-dimensional data and (b) portability of the indices across multiple computer platforms. We will present an API that simplifies the execution of queries on HDF5 files for general scientific applications and data analysis. The design is flexible enough to accommodate the use of arbitrary indexing technology for semantic range queries. We will also provide a detailed performance analysis of HDF5-FastQuery for both synthetic and scientific data. The results demonstrate that our proposed approach for multi-dimensional queries is up to a factor of 2 faster than HDF5.

  8. Development of a cryogenic load frame for the neutron diffractometer at Takumi in Japan Proton Accelerator Research Complex

    SciTech Connect

    Jin, Xinzhe; Nakamoto, Tatsushi; Ogitsu, Toru; Yamamoto, Akira; Sugano, Michinaka; Harjo, Stefanus; Aizawa, Kazuya; Abe, Jun; Gong, Wu; Iwahashi, Takaaki; Hemmi, Tsutomu; Umeno, Takahiro

    2013-06-15

    To prepare for projects such as the Large Hadron Collider upgrade, International Thermonuclear Experimental Reactor and Demonstration reactor, it is important to form a clear understanding of stress-strain properties of the materials that make up superconducting magnets. Thus, we have been studying the mechanical properties of superconducting wires using neutron diffraction measurements. To simulate operational conditions such as temperature, stress, and strain, we developed a cryogenic load frame for stress-strain measurements of materials using a neutron diffractometer at Japan Proton Accelerator Research Complex (J-PARC) Takumi beam line. The maximum load that can be applied to a sample using an external driving machine is 50 kN. Using a Gifford-MacMahon cryocooler, samples can be measured down to temperatures below 10 K when loaded. In the present paper, we describe the details of the cryogenic load frame with its test results by using type-304 stainless steel wire.

  9. Development of a cryogenic load frame for the neutron diffractometer at Takumi in Japan Proton Accelerator Research Complex.

    PubMed

    Jin, Xinzhe; Nakamoto, Tatsushi; Harjo, Stefanus; Hemmi, Tsutomu; Umeno, Takahiro; Ogitsu, Toru; Yamamoto, Akira; Sugano, Michinaka; Aizawa, Kazuya; Abe, Jun; Gong, Wu; Iwahashi, Takaaki

    2013-06-01

    To prepare for projects such as the Large Hadron Collider upgrade, International Thermonuclear Experimental Reactor and Demonstration reactor, it is important to form a clear understanding of stress-strain properties of the materials that make up superconducting magnets. Thus, we have been studying the mechanical properties of superconducting wires using neutron diffraction measurements. To simulate operational conditions such as temperature, stress, and strain, we developed a cryogenic load frame for stress-strain measurements of materials using a neutron diffractometer at Japan Proton Accelerator Research Complex (J-PARC) Takumi beam line. The maximum load that can be applied to a sample using an external driving machine is 50 kN. Using a Gifford-MacMahon cryocooler, samples can be measured down to temperatures below 10 K when loaded. In the present paper, we describe the details of the cryogenic load frame with its test results by using type-304 stainless steel wire. PMID:23822332

  10. First high-power model of the annular-ring coupled structure for use in the Japan Proton Accelerator Research Complex linac

    NASA Astrophysics Data System (ADS)

    Ao, Hiroyuki; Yamazaki, Yoshishige

    2012-01-01

    A prototype cavity for the annular-ring coupled structure (ACS) for use in the Japan Proton Accelerator Research Complex (J-PARC) linac has been developed to confirm the feasibility of achieving the required performance. This prototype cavity is a buncher module, which includes ten accelerating cells in total. The ACS cavity is formed by the silver brazing of ACS half-cell pieces stacked in a vacuum furnace. The accelerating cell of the ACS is surrounded by a coupling cell. We, therefore, tuned the frequencies of the accelerating and coupling cells by an ultraprecision lathe before brazing, taking into account the frequency shift due to brazing. The prototype buncher module was successfully conditioned up to 600 kW, which corresponds to an accelerating field that is higher than the designed field of 4.1MV/m by 30%. We describe the frequency-tuning results for the prototype buncher module and its high-power conditioning.

  11. Surrogate accelerated sampling of reservoir models with complex structures using sparse polynomial chaos expansion

    NASA Astrophysics Data System (ADS)

    Bazargan, Hamid; Christie, Mike; Elsheikh, Ahmed H.; Ahmadi, Mohammad

    2015-12-01

    Markov Chain Monte Carlo (MCMC) methods are often used to probe the posterior probability distribution in inverse problems. This allows for computation of estimates of uncertain system responses conditioned on given observational data by means of approximate integration. However, MCMC methods suffer from the computational complexities in the case of expensive models as in the case of subsurface flow models. Hence, it is of great interest to develop alterative efficient methods utilizing emulators, that are cheap to evaluate, in order to replace the full physics simulator. In the current work, we develop a technique based on sparse response surfaces to represent the flow response within a subsurface reservoir and thus enable efficient exploration of the posterior probability density function and the conditional expectations given the data. Polynomial Chaos Expansion (PCE) is a powerful tool to quantify uncertainty in dynamical systems when there is probabilistic uncertainty in the system parameters. In the context of subsurface flow model, it has been shown to be more accurate and efficient compared with traditional experimental design (ED). PCEs have a significant advantage over other response surfaces as the convergence to the true probability distribution when the order of the PCE is increased can be proved for the random variables with finite variances. However, the major drawback of PCE is related to the curse of dimensionality as the number of terms to be estimated grows drastically with the number of the input random variables. This renders the computational cost of classical PCE schemes unaffordable for reservoir simulation purposes when the deterministic finite element model is expensive to evaluate. To address this issue, we propose the reduced-terms polynomial chaos representation which uses an impact factor to only retain the most relevant terms of the PCE decomposition. Accordingly, the reduced-terms polynomial chaos proxy can be used as the pseudo

  12. Lewis acid-base interactions between platinum(ii) diaryl complexes and bis(perfluorophenyl)zinc: strongly accelerated reductive elimination induced by a Z-type ligand.

    PubMed

    Liberman-Martin, Allegra L; Levine, Daniel S; Ziegler, Micah S; Bergman, Robert G; Tilley, T Don

    2016-05-19

    Z-type interactions between bis(perfluorophenyl)zinc and platinum(ii) diaryl complexes supported by 1,10-phenanthroline (phen), 2,2'-bipyridine (bpy), and bis(dimethylphosphino)ethane (dmpe) ligands are reported. In the solid state, the nature of the Pt-Zn interaction depends on the bidentate ligand; the phen-supported complex exhibits an unsupported Pt-Zn bond, while the dmpe derivative features additional bridging aryl interactions. A strongly accelerated rate of reductive elimination is observed for phen- and bpy-supported complexes, while aryl exchange between Pt and Zn is observed for the dmpe complex. PMID:27161155

  13. Self-consistent-field modeling of complex molecules with united atom detail in inhomogeneous systems. Cyclic and branched foreign molecules in dimyristoylphosphatidylcholine membranes

    NASA Astrophysics Data System (ADS)

    Meijer, L. A.; Leermakers, F. A. M.; Lyklema, J.

    1999-04-01

    We have developed a detailed self-consistent-field model for studying complex molecules in inhomogeneous systems, in which all the molecules are represented in a detailed united atom description. The theory is in the spirit of the approach developed by Scheutjens and co-workers for polymers at interfaces and self-assembly of surfactants and lipids into association colloids. It is applied to lipid membranes composed of dimyristoylphosphatidylcholine (DMPC). In particular, we looked at the incorporation of linear, branched, and cyclic molecules into the lipid bilayers being in the liquid phase. Detailed information on the properties of both the lipids and the additives is presented. For the classes of linear and branched alcohols and phenol derivatives we find good correspondence between calculated partition coefficients for DMPC membranes and experimental data on egg-yolk PC. The calculated partitioning of molecules of isomers, containing a benzene ring, two charged groups (one positive and one negative) and 16 hydrocarbon segments, into DMPC membranes showed variations of the partition coefficient by a factor of 10 depending on the molecular architecture. For zwitterionic additives we find that it is much more difficult to bring the positive charge into the membrane core than the negative one. This result can be rationalized from information on the electrostatic potential profile of the bare membrane, being positive in both the core and on the membrane surface but negative near the position of the phosphate groups. For several tetrahydroxy naftalenes we found that, although the partition coefficient is barely influenced, the average orientation and position of the molecule inside the membrane is strongly dependent on the distribution of the hydroxyl groups on the naphthalene rings. The orientation changes from one where the additive spans the membrane when the hydroxyls are positioned on (2,3,6,7) positions, to an orientation with the rings parallel to the membrane

  14. Analytical gradients of complete active space self-consistent field energies using Cholesky decomposition: Geometry optimization and spin-state energetics of a ruthenium nitrosyl complex

    SciTech Connect

    Delcey, Mickaël G.; Freitag, Leon; González, Leticia; Pedersen, Thomas Bondo; Aquilante, Francesco; Lindh, Roland

    2014-05-07

    We present a formulation of analytical energy gradients at the complete active space self-consistent field (CASSCF) level of theory employing density fitting (DF) techniques to enable efficient geometry optimizations of large systems. As an example, the ground and lowest triplet state geometries of a ruthenium nitrosyl complex are computed at the DF-CASSCF level of theory and compared with structures obtained from density functional theory (DFT) using the B3LYP, BP86, and M06L functionals. The average deviation of all bond lengths compared to the crystal structure is 0.042 Å at the DF-CASSCF level of theory, which is slightly larger but still comparable with the deviations obtained by the tested DFT functionals, e.g., 0.032 Å with M06L. Specifically, the root-mean-square deviation between the DF-CASSCF and best DFT coordinates, delivered by BP86, is only 0.08 Å for S{sub 0} and 0.11 Å for T{sub 1}, indicating that the geometries are very similar. While keeping the mean energy gradient errors below 0.25%, the DF technique results in a 13-fold speedup compared to the conventional CASSCF geometry optimization algorithm. Additionally, we assess the singlet-triplet energy vertical and adiabatic differences with multiconfigurational second-order perturbation theory (CASPT2) using the DF-CASSCF and DFT optimized geometries. It is found that the vertical CASPT2 energies are relatively similar regardless of the geometry employed whereas the adiabatic singlet-triplet gaps are more sensitive to the chosen triplet geometry.

  15. The endothelial cell binding site for advanced glycation end products consists of a complex: an integral membrane protein and a lactoferrin-like polypeptide.

    PubMed

    Schmidt, A M; Mora, R; Cao, R; Yan, S D; Brett, J; Ramakrishnan, R; Tsang, T C; Simionescu, M; Stern, D

    1994-04-01

    Advanced glycation end products (AGEs), formed as the result of the extended interaction of proteins with ketoses, modulate central properties of endothelial cells and mononuclear phagocytes by interacting with a cell surface binding site comprised of a novel integral membrane protein (receptor for AGE = RAGE) and a lactoferrin-like polypeptide (LF-L), the latter having sequence identity to lactoferrin (LF). To further understand this cellular binding site, the interaction of RAGE with LF-L and LF was characterized. By ligand blotting and a solid state competitive binding assay, 125I-LF-L and 125I-LF bound to RAGE immobilized on nitrocellulose membranes or polypropylene tubes in a time-dependent and reversible manner, demonstrating a high affinity component with Kd approximately 100 pM. The interaction of 125I-LF-L and 125I-LF with RAGE was independent of iron in LF and was competed by addition of an excess of unlabeled carboxyl-terminal portion of LF. Cross-linking studies with purified 125I-LF-L and RAGE, in the presence of disuccinimidyl suberate, showed a new, slowly migrating band, corresponding to a complex of RAGE and LF-L, and cross-linking on mouse aortic endothelial cells showed two new slowly migrating bands on immunoblotting visualized with both anti-RAGE IgG and anti-LF-L IgG. These data lead us to propose that the endothelial cell surface binding site for AGEs consists of LF-L bound noncovalently to RAGE anchored in the cell membrane. PMID:8144581

  16. Fc-based delivery system enhances immunogenicity of a tuberculosis subunit vaccine candidate consisting of the ESAT-6:CFP-10 complex.

    PubMed

    Farsiani, Hadi; Mosavat, Arman; Soleimanpour, Saman; Sadeghian, Hamid; Akbari Eydgahi, Mohammad Reza; Ghazvini, Kiarash; Sankian, Mojtaba; Aryan, Ehsan; Jamehdar, Saeid Amel; Rezaee, Seyed Abdolrahim

    2016-06-21

    Tuberculosis (TB) remains a major global health threat despite chemotherapy and Bacilli Calmette-Guérin (BCG) vaccination. Therefore, a safer and more effective vaccine against TB is urgently needed. This study evaluated the immunogenicity of a recombinant fusion protein consisting of early secreted antigenic target protein 6 kDa (ESAT-6), culture filtrate protein 10 kDa (CFP-10) and the Fc-domain of mouse IgG2a as a novel subunit vaccine. The recombinant expression vectors (pPICZαA-ESAT-6:CFP-10:Fcγ2a and pPICZαA-ESAT-6:CFP-10:His) were transferred into Pichia pastoris. After SDS-PAGE and immunoblotting, the immunogenicity of the recombinant proteins was evaluated in mice. When both recombinant proteins (ESAT-6:CFP-10:Fcγ2a and ESAT-6:CFP-10:His) were used for vaccination, Th1-type cellular responses were induced producing high levels of IFN-γ and IL-12. However, the Fc-tagged recombinant protein induced more effective Th1-type cellular responses with a small increase in IL-4 as compared to the BCG and ESAT-6:CFP-10:His groups. Moreover, mice primed with BCG and then supplemented with ESAT-6:CFP-10:Fcγ2a produced the highest levels of IFN-γ and IL-12 in immunized groups. The findings indicate that when Fcγ2a is fused to the ESAT-6:CFP-10 complex, as a delivery vehicle, there could be an increase in the immunogenicity of this type of subunit vaccine. Therefore, additional investigations are necessary for the development of appropriate Fc-based tuberculosis vaccines. PMID:27138226

  17. Analytical gradients of complete active space self-consistent field energies using Cholesky decomposition: geometry optimization and spin-state energetics of a ruthenium nitrosyl complex.

    PubMed

    Delcey, Mickaël G; Freitag, Leon; Pedersen, Thomas Bondo; Aquilante, Francesco; Lindh, Roland; González, Leticia

    2014-05-01

    We present a formulation of analytical energy gradients at the complete active space self-consistent field (CASSCF) level of theory employing density fitting (DF) techniques to enable efficient geometry optimizations of large systems. As an example, the ground and lowest triplet state geometries of a ruthenium nitrosyl complex are computed at the DF-CASSCF level of theory and compared with structures obtained from density functional theory (DFT) using the B3LYP, BP86, and M06L functionals. The average deviation of all bond lengths compared to the crystal structure is 0.042 Å at the DF-CASSCF level of theory, which is slightly larger but still comparable with the deviations obtained by the tested DFT functionals, e.g., 0.032 Å with M06L. Specifically, the root-mean-square deviation between the DF-CASSCF and best DFT coordinates, delivered by BP86, is only 0.08 Å for S0 and 0.11 Å for T1, indicating that the geometries are very similar. While keeping the mean energy gradient errors below 0.25%, the DF technique results in a 13-fold speedup compared to the conventional CASSCF geometry optimization algorithm. Additionally, we assess the singlet-triplet energy vertical and adiabatic differences with multiconfigurational second-order perturbation theory (CASPT2) using the DF-CASSCF and DFT optimized geometries. It is found that the vertical CASPT2 energies are relatively similar regardless of the geometry employed whereas the adiabatic singlet-triplet gaps are more sensitive to the chosen triplet geometry. PMID:24811621

  18. Analytical gradients of complete active space self-consistent field energies using Cholesky decomposition: Geometry optimization and spin-state energetics of a ruthenium nitrosyl complex

    NASA Astrophysics Data System (ADS)

    Delcey, Mickaël G.; Freitag, Leon; Pedersen, Thomas Bondo; Aquilante, Francesco; Lindh, Roland; González, Leticia

    2014-05-01

    We present a formulation of analytical energy gradients at the complete active space self-consistent field (CASSCF) level of theory employing density fitting (DF) techniques to enable efficient geometry optimizations of large systems. As an example, the ground and lowest triplet state geometries of a ruthenium nitrosyl complex are computed at the DF-CASSCF level of theory and compared with structures obtained from density functional theory (DFT) using the B3LYP, BP86, and M06L functionals. The average deviation of all bond lengths compared to the crystal structure is 0.042 Å at the DF-CASSCF level of theory, which is slightly larger but still comparable with the deviations obtained by the tested DFT functionals, e.g., 0.032 Å with M06L. Specifically, the root-mean-square deviation between the DF-CASSCF and best DFT coordinates, delivered by BP86, is only 0.08 Å for S0 and 0.11 Å for T1, indicating that the geometries are very similar. While keeping the mean energy gradient errors below 0.25%, the DF technique results in a 13-fold speedup compared to the conventional CASSCF geometry optimization algorithm. Additionally, we assess the singlet-triplet energy vertical and adiabatic differences with multiconfigurational second-order perturbation theory (CASPT2) using the DF-CASSCF and DFT optimized geometries. It is found that the vertical CASPT2 energies are relatively similar regardless of the geometry employed whereas the adiabatic singlet-triplet gaps are more sensitive to the chosen triplet geometry.

  19. Direct observation of the phase space footprint of a painting injection in the Rapid Cycling Synchrotron at the Japan Proton Accelerator Research Complex

    NASA Astrophysics Data System (ADS)

    Saha, P. K.; Shobuda, Y.; Hotchi, H.; Hayashi, N.; Takayanagi, T.; Harada, H.; Irie, Y.

    2009-04-01

    The 3 GeV Rapid Cycling Synchrotron (RCS) at Japan Proton Accelerator Research Complex is nearly at the operational stage with regard to the beam commissioning aspects. Recently, the design painting injection study has been commenced with the aim of high output beam power at the extraction. In order to observe the phase space footprint of the painting injection, a method was developed utilizing a beam position monitor (BPM) in the so-called single pass mode. The turn-by-turn phase space coordinates of the circulating beam directly measured using a pair of BPMs entirely positioned in drift space, and the calculated transfer matrices from the injection point to the pair of BPMs with several successive turns were used together in order to obtain the phase space footprint of the painting injection. There are two such pairs of BPMs placed in two different locations in the RCS, the results from which both agreed and were quite consistent with what was expected.

  20. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  1. Lazy arc consistency

    SciTech Connect

    Schiex, T.; Gaspin, C.; Regin, J.C.; Verfaillie, G.

    1996-12-31

    Arc consistency filtering is widely used in the framework of binary constraint satisfaction problems: with a low complexity, inconsistency may be detected and domains are filtered. In this paper, we show that when detecting inconsistency is the objective, a systematic domain filtering is useless and a lazy approach is more adequate. Whereas usual arc consistency algorithms produce the maximum arc consistent sub-domain, when it exists, we propose a method, called LAC{tau}, which only looks for any arc consistent sub-domain. The algorithm is then extended to provide the additional service of locating one variable with a minimum domain cardinality in the maximum arc consistent sub-domain, without necessarily computing all domain sizes. Finally, we compare traditional AC enforcing and lazy AC enforcing using several benchmark problems, both randomly generated CSP and real life problems.

  2. Highly Effective Non-Viral Antitumor Gene Therapy System Comprised of Biocompatible Small Plasmid Complex Particles Consisting of pDNA, Anionic Polysaccharide, and Fully Deprotected Linear Polyethylenimine

    PubMed Central

    Koyama, Yoshiyuki; Sugiura, Kikuya; Yoshihara, Chieko; Inaba, Toshio; Ito, Tomoko

    2015-01-01

    We have reported that ternary complexes of plasmid DNA with conventional linear polyethylenimine (l-PEI) and certain polyanions were very stably dispersed, and, with no cryoprotectant, they could be freeze-dried and re-hydrated without the loss of transfection ability. These properties enabled the preparation of a concentrated suspension of very small pDNA complex, by preparing the complexes at highly diluted conditions, followed by condensation via lyophilization-and-rehydration procedure. Recently, a high potency linear polyethylenimine having no residual protective groups, i.e., Polyethylenimine “Max” (PEI “Max”), is available, which has been reported to induce much higher gene expression than conventional l-PEI. We tried to prepare the small DNA/PEI “Max”/polyanion complexes by a similar freeze-drying method. Small complex particles could be obtained without apparent aggregation, but transfection activity of the rehydrated complexes was severely reduced. Complex-preparation conditions were investigated in details to achieve the freeze-dried DNA/PEI “Max”/polyanion small ternary complexes with high transfection efficiency. DNA/PEI “Max”/polyanion complexes containing cytokine-coding plasmids were then prepared, and their anti-tumor therapeutic efficacy was examined in tumor-bearing mice. PMID:26213961

  3. The Spallation Neutron Source accelerator system design

    NASA Astrophysics Data System (ADS)

    Henderson, S.; Abraham, W.; Aleksandrov, A.; Allen, C.; Alonso, J.; Anderson, D.; Arenius, D.; Arthur, T.; Assadi, S.; Ayers, J.; Bach, P.; Badea, V.; Battle, R.; Beebe-Wang, J.; Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E.; Blaskiewicz, M.; Blind, B.; Blokland, W.; Bookwalter, V.; Borovina, D.; Bowling, S.; Bradley, J.; Brantley, C.; Brennan, J.; Brodowski, J.; Brown, S.; Brown, R.; Bruce, D.; Bultman, N.; Cameron, P.; Campisi, I.; Casagrande, F.; Catalan-Lasheras, N.; Champion, M.; Champion, M.; Chen, Z.; Cheng, D.; Cho, Y.; Christensen, K.; Chu, C.; Cleaves, J.; Connolly, R.; Cote, T.; Cousineau, S.; Crandall, K.; Creel, J.; Crofford, M.; Cull, P.; Cutler, R.; Dabney, R.; Dalesio, L.; Daly, E.; Damm, R.; Danilov, V.; Davino, D.; Davis, K.; Dawson, C.; Day, L.; Deibele, C.; Delayen, J.; DeLong, J.; Demello, A.; DeVan, W.; Digennaro, R.; Dixon, K.; Dodson, G.; Doleans, M.; Doolittle, L.; Doss, J.; Drury, M.; Elliot, T.; Ellis, S.; Error, J.; Fazekas, J.; Fedotov, A.; Feng, P.; Fischer, J.; Fox, W.; Fuja, R.; Funk, W.; Galambos, J.; Ganni, V.; Garnett, R.; Geng, X.; Gentzlinger, R.; Giannella, M.; Gibson, P.; Gillis, R.; Gioia, J.; Gordon, J.; Gough, R.; Greer, J.; Gregory, W.; Gribble, R.; Grice, W.; Gurd, D.; Gurd, P.; Guthrie, A.; Hahn, H.; Hardek, T.; Hardekopf, R.; Harrison, J.; Hatfield, D.; He, P.; Hechler, M.; Heistermann, F.; Helus, S.; Hiatt, T.; Hicks, S.; Hill, J.; Hill, J.; Hoff, L.; Hoff, M.; Hogan, J.; Holding, M.; Holik, P.; Holmes, J.; Holtkamp, N.; Hovater, C.; Howell, M.; Hseuh, H.; Huhn, A.; Hunter, T.; Ilg, T.; Jackson, J.; Jain, A.; Jason, A.; Jeon, D.; Johnson, G.; Jones, A.; Joseph, S.; Justice, A.; Kang, Y.; Kasemir, K.; Keller, R.; Kersevan, R.; Kerstiens, D.; Kesselman, M.; Kim, S.; Kneisel, P.; Kravchuk, L.; Kuneli, T.; Kurennoy, S.; Kustom, R.; Kwon, S.; Ladd, P.; Lambiase, R.; Lee, Y. Y.; Leitner, M.; Leung, K.-N.; Lewis, S.; Liaw, C.; Lionberger, C.; Lo, C. C.; Long, C.; Ludewig, H.; Ludvig, J.; Luft, P.; Lynch, M.; Ma, H.; MacGill, R.; Macha, K.; Madre, B.; Mahler, G.; Mahoney, K.; Maines, J.; Mammosser, J.; Mann, T.; Marneris, I.; Marroquin, P.; Martineau, R.; Matsumoto, K.; McCarthy, M.; McChesney, C.; McGahern, W.; McGehee, P.; Meng, W.; Merz, B.; Meyer, R.; Meyer, R.; Miller, B.; Mitchell, R.; Mize, J.; Monroy, M.; Munro, J.; Murdoch, G.; Musson, J.; Nath, S.; Nelson, R.; Nelson, R.; O`Hara, J.; Olsen, D.; Oren, W.; Oshatz, D.; Owens, T.; Pai, C.; Papaphilippou, I.; Patterson, N.; Patterson, J.; Pearson, C.; Pelaia, T.; Pieck, M.; Piller, C.; Plawski, T.; Plum, M.; Pogge, J.; Power, J.; Powers, T.; Preble, J.; Prokop, M.; Pruyn, J.; Purcell, D.; Rank, J.; Raparia, D.; Ratti, A.; Reass, W.; Reece, K.; Rees, D.; Regan, A.; Regis, M.; Reijonen, J.; Rej, D.; Richards, D.; Richied, D.; Rode, C.; Rodriguez, W.; Rodriguez, M.; Rohlev, A.; Rose, C.; Roseberry, T.; Rowton, L.; Roybal, W.; Rust, K.; Salazer, G.; Sandberg, J.; Saunders, J.; Schenkel, T.; Schneider, W.; Schrage, D.; Schubert, J.; Severino, F.; Shafer, R.; Shea, T.; Shishlo, A.; Shoaee, H.; Sibley, C.; Sims, J.; Smee, S.; Smith, J.; Smith, K.; Spitz, R.; Staples, J.; Stein, P.; Stettler, M.; Stirbet, M.; Stockli, M.; Stone, W.; Stout, D.; Stovall, J.; Strelo, W.; Strong, H.; Sundelin, R.; Syversrud, D.; Szajbler, M.; Takeda, H.; Tallerico, P.; Tang, J.; Tanke, E.; Tepikian, S.; Thomae, R.; Thompson, D.; Thomson, D.; Thuot, M.; Treml, C.; Tsoupas, N.; Tuozzolo, J.; Tuzel, W.; Vassioutchenko, A.; Virostek, S.; Wallig, J.; Wanderer, P.; Wang, Y.; Wang, J. G.; Wangler, T.; Warren, D.; Wei, J.; Weiss, D.; Welton, R.; Weng, J.; Weng, W.-T.; Wezensky, M.; White, M.; Whitlatch, T.; Williams, D.; Williams, E.; Wilson, K.; Wiseman, M.; Wood, R.; Wright, P.; Wu, A.; Ybarrolaza, N.; Young, K.; Young, L.; Yourd, R.; Zachoszcz, A.; Zaltsman, A.; Zhang, S.; Zhang, W.; Zhang, Y.; Zhukov, A.

    2014-11-01

    The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ~100 high-power RF power systems, a 2 K cryogenic plant, ~400 DC and pulsed power supply systems, ~400 beam diagnostic devices and a distributed control system handling ~100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

  4. In vitro reconstitution of a heterotrimeric nucleoporin complex consisting of recombinant Nsp1p, Nup49p, and Nup57p.

    PubMed Central

    Schlaich, N L; Häner, M; Lustig, A; Aebi, U; Hurt, E C

    1997-01-01

    The yeast nucleoporins Nsp1p, Nup49p, and Nup57p form a complex at the nuclear pores which is involved in nucleocytoplasmic transport. To investigate the molecular basis underlying complex formation, recombinant full-length Nup49p and Nup57p and the carboxyl-terminal domain of Nsp1p, which lacks the FXFG repeat domain, were expressed in Escherichia coli. When the three purified proteins were mixed together, they spontaneously associated to form a 150-kDa complex of 1:1:1 stoichiometry. In this trimeric complex, Nup57p fulfills the role of an organizing center, to which Nup49p and Nsp1p individually bind. For this interaction to occur, only two heptad repeat regions of the Nsp1p carboxyl-terminal domain are required, each region being about 50 amino acids in length. Finally, the reconstituted complex has the capability to bind to full-length Nic96p but not to mutant forms which also do not interact in vivo. When added to permeabilized yeast cells, the complex associates with the nuclear envelope and the nuclear pores. We conclude that Nsp1p, Nup49p, and Nup57p can reconstitute a complex in vitro which is competent for further assembly with other components of nuclear pores. Images PMID:9017593

  5. Multidimensional earthquake frequency distributions consistent with self-organization of complex systems: The interdependence of magnitude, interevent time and interevent distance

    NASA Astrophysics Data System (ADS)

    Tzanis, A.; Vallianatos, F.

    2012-04-01

    It is well known that earthquake frequency is related to earthquake magnitude via a simple linear relationship of the form logN = a - bM, where N is the number of earthquakes in a specified time interval; this is the famous Gutenberg - Richter (G-R) law. The generally accepted interpretation of the G-R law is that it expresses the statistical behaviour of a fractal active tectonic grain (active faulting) - the relationship between the constant b and the fractal dimension of the tectonic grain has been demonstrated in various ways. The story told by the G-R law is, nevertheless, incomplete! It is now accepted that the active tectonic grain comprises a critical complex system, although it hasn't yet been established whether it is stationary (Self-Organized Critical), evolutionary (Self-Organizing Critical), or a time-varying blend of both. At any rate, critical systems are characterized by strong interactions between near and distant neighbours. This, in turn, implies that the self-organization of earthquake occurrence should be manifested by certain statistical behaviour of its temporal and spatial dependence. A measure of temporal dependence is the time lapsed between consecutive events above a magnitude threshold over a given area (interevent time). A measure of spatial dependence is the hypocentral distance between consecutive events above a magnitude threshold over a given area (interevent distance). The statistics of earthquake frequency - interevent times have been studied by several researchers, albeit frequently on the basis of different definition for the interevent time. The statistics of earthquake frequency - interevent distance is still terra incognita. Herein we present a multidimensional analysis of the statistical behaviour of frequency - magnitude - interevent time, frequency - magnitude - interevent distance and frequency - interevent time - interevent distance. We demonstrate that earthquake frequency is multiply related, not only to magnitude as

  6. Chiral SiO2 and Ag@SiO2 Materials Templated by Complexes Consisting of Comblike Polyethyleneimine and Tartaric Acid.

    PubMed

    Yao, Dong-Dong; Murata, Hiroki; Tsunega, Seiji; Jin, Ren-Hua

    2015-10-26

    A facile avenue to fabricate micrometer-sized chiral (L-, D-) and meso-like (dl-) SiO2 materials with unique structures by using crystalline complexes (cPEI/tart), composed of comblike polyethyleneimine (cPEI) and L-, D-, or dl-tartaric acid, respectively, as catalytic templates is reported. Interestingly, both chiral crystalline complexes appeared as regularly left- and right-twisted bundle structures about 10 μm in length and about 5 μm in diameter, whereas the dl-form occurred as circular structures with about 10 μm diameter. Subsequently, SiO2 @cPEI/tart hybrids with high silica content (>55.0 wt %) were prepared by stirring a mixture containing tetramethoxysilane (TMOS) and the aggregates of the crystalline complexes in water. The chiral SiO2 hybrids and calcined chiral SiO2 showed very strong CD signals and a nanofiber-based morphology on their surface, whereas dl-SiO2 showed no CD activity and a nanosheet-packed disklike shape. Furthermore, metallic silver nanoparticles (Ag NPs) were encapsulated in each silica hybrid to obtain chiral (D and L forms) and meso-like (dl form) Ag@SiO2 composites. Also, the reaction between L-cysteine (Lcys) and these Ag@SiO2 composites was preliminarily investigated. Only chiral L- and D-Ag@SiO2 composites promoted the reaction between Lcys and Ag NPs to produce a molecular [Ag-Lcys]n complex with remarkable exciton chirality, whereas the reaction hardly occurred in the case of meso-like (dl-) Ag@SiO2 composite. PMID:26350940

  7. Nature-Inspired, Highly Durable CO2 Reduction System Consisting of a Binuclear Ruthenium(II) Complex and an Organic Semiconductor Using Visible Light.

    PubMed

    Kuriki, Ryo; Matsunaga, Hironori; Nakashima, Takuya; Wada, Keisuke; Yamakata, Akira; Ishitani, Osamu; Maeda, Kazuhiko

    2016-04-20

    A metal-free organic semiconductor of mesoporous graphitic carbon nitride (C3N4) coupled with a Ru(II) binuclear complex (RuRu') containing photosensitizer and catalytic units selectively reduced CO2 into HCOOH under visible light (λ > 400 nm) in the presence of a suitable electron donor with high durability, even in aqueous solution. Modification of C3N4 with Ag nanoparticles resulted in a RuRu'/Ag/C3N4 photocatalyst that exhibited a very high turnover number (>33000 with respect to the amount of RuRu'), while maintaining high selectivity for HCOOH production (87-99%). This turnover number was 30 times greater than that reported previously using C3N4 modified with a mononuclear Ru(II) complex, and by far the highest among the metal-complex/semiconductor hybrid systems reported to date. The results of photocatalytic reactions, emission decay measurements, and time-resolved infrared spectroscopy indicated that Ag nanoparticles on C3N4 collected electrons having lifetimes of several milliseconds from the conduction band of C3N4, which were transferred to the excited state of RuRu', thereby promoting photocatalytic CO2 reduction driven by two-step photoexcitation of C3N4 and RuRu'. This study also revealed that the RuRu'/Ag/C3N4 hybrid photocatalyst worked efficiently in water containing a proper electron donor, despite the intrinsic hydrophobic nature of C3N4 and low solubility of CO2 in an aqueous environment. PMID:27027822

  8. A Sensory Complex Consisting of an ATP-binding Cassette Transporter and a Two-component Regulatory System Controls Bacitracin Resistance in Bacillus subtilis*

    PubMed Central

    Dintner, Sebastian; Heermann, Ralf; Fang, Chong; Jung, Kirsten; Gebhard, Susanne

    2014-01-01

    Resistance against antimicrobial peptides in many Firmicutes bacteria is mediated by detoxification systems that are composed of a two-component regulatory system (TCS) and an ATP-binding cassette (ABC) transporter. The histidine kinases of these systems depend entirely on the transporter for sensing of antimicrobial peptides, suggesting a novel mode of signal transduction where the transporter constitutes the actual sensor. The aim of this study was to investigate the molecular mechanisms of this unusual signaling pathway in more detail, using the bacitracin resistance system BceRS-BceAB of Bacillus subtilis as an example. To analyze the proposed communication between TCS and the ABC transporter, we characterized their interactions by bacterial two-hybrid analyses and could show that the permease BceB and the histidine kinase BceS interact directly. In vitro pulldown assays confirmed this interaction, which was found to be independent of bacitracin. Because it was unknown whether BceAB-type transporters could detect their substrate peptides directly or instead recognized the peptide-target complex in the cell envelope, we next analyzed substrate binding by the transport permease, BceB. Direct and specific binding of bacitracin by BceB was demonstrated by surface plasmon resonance spectroscopy. Finally, in vitro signal transduction assays indicated that complex formation with the transporter influenced the autophosphorylation activity of the histidine kinase. Taken together, our findings clearly show the existence of a sensory complex composed of TCS and ABC transporters and provide the first functional insights into the mechanisms of stimulus perception, signal transduction, and antimicrobial resistance employed by Bce-like detoxification systems. PMID:25118291

  9. Are there consistent grazing indicators in Drylands? Testing plant functional types of various complexity in South Africa's Grassland and Savanna Biomes.

    PubMed

    Linstädter, Anja; Schellberg, Jürgen; Brüser, Katharina; Moreno García, Cristian A; Oomen, Roelof J; du Preez, Chris C; Ruppert, Jan C; Ewert, Frank

    2014-01-01

    Despite our growing knowledge on plants' functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs) with a consistent response to grazing across two areas differing in climatic aridity, situated in South Africa's grassland and savanna biomes. We aggregated herbaceous species into PFTs, using hierarchical combinations of traits (from single- to three-trait PFTs). Traits relate to life history, growth form and leaf width. We first confirmed that soil and grazing gradients were largely independent from each other, and then searched in each biome for PFTs with a sensitive response to grazing, avoiding confounding with soil conditions. We found no response consistency, but biome-specific optimum aggregation levels. Three-trait PFTs (e.g. broad-leaved perennial grasses) and two-trait PFTs (e.g. perennial grasses) performed best as indicators of grazing effects in the semi-arid grassland and in the arid savanna biome, respectively. Some PFTs increased with grazing pressure in the grassland, but decreased in the savanna. We applied biome-specific grazing indicators to evaluate if differences in grazing management related to land tenure (communal versus freehold) had effects on vegetation. Tenure effects were small, which we mainly attributed to large variability in grazing pressure across farms. We conclude that the striking lack of generalizable PFT responses to grazing is due to a convergence of aridity and grazing effects, and unlikely to be overcome by more refined classification approaches. Hence, PFTs with an opposite response to grazing in the two biomes rather have a unimodal response along a gradient of additive forces of aridity and grazing. The study advocates for hierarchical trait combinations to identify localized indicator sets for grazing effects. Its methodological approach may also be useful

  10. Are There Consistent Grazing Indicators in Drylands? Testing Plant Functional Types of Various Complexity in South Africa’s Grassland and Savanna Biomes

    PubMed Central

    Linstädter, Anja; Schellberg, Jürgen; Brüser, Katharina; Moreno García, Cristian A.; Oomen, Roelof J.; du Preez, Chris C.; Ruppert, Jan C.; Ewert, Frank

    2014-01-01

    Despite our growing knowledge on plants’ functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs) with a consistent response to grazing across two areas differing in climatic aridity, situated in South Africa’s grassland and savanna biomes. We aggregated herbaceous species into PFTs, using hierarchical combinations of traits (from single- to three-trait PFTs). Traits relate to life history, growth form and leaf width. We first confirmed that soil and grazing gradients were largely independent from each other, and then searched in each biome for PFTs with a sensitive response to grazing, avoiding confounding with soil conditions. We found no response consistency, but biome-specific optimum aggregation levels. Three-trait PFTs (e.g. broad-leaved perennial grasses) and two-trait PFTs (e.g. perennial grasses) performed best as indicators of grazing effects in the semi-arid grassland and in the arid savanna biome, respectively. Some PFTs increased with grazing pressure in the grassland, but decreased in the savanna. We applied biome-specific grazing indicators to evaluate if differences in grazing management related to land tenure (communal versus freehold) had effects on vegetation. Tenure effects were small, which we mainly attributed to large variability in grazing pressure across farms. We conclude that the striking lack of generalizable PFT responses to grazing is due to a convergence of aridity and grazing effects, and unlikely to be overcome by more refined classification approaches. Hence, PFTs with an opposite response to grazing in the two biomes rather have a unimodal response along a gradient of additive forces of aridity and grazing. The study advocates for hierarchical trait combinations to identify localized indicator sets for grazing effects. Its methodological approach may also be

  11. The direction of acceleration

    NASA Astrophysics Data System (ADS)

    Wilhelm, Thomas; Burde, Jan-Philipp; Lück, Stephan

    2015-11-01

    Acceleration is a physical quantity that is difficult to understand and hence its complexity is often erroneously simplified. Many students think of acceleration as equivalent to velocity, a ˜ v. For others, acceleration is a scalar quantity, which describes the change in speed Δ|v| or Δ|v|/Δt (as opposed to the change in velocity). The main difficulty with the concept of acceleration therefore lies in developing a correct understanding of its direction. The free iOS app AccelVisu supports students in acquiring a correct conception of acceleration by showing acceleration arrows directly at moving objects.

  12. Acceleration of Monte Carlo simulation of photon migration in complex heterogeneous media using Intel many-integrated core architecture.

    PubMed

    Gorshkov, Anton V; Kirillin, Mikhail Yu

    2015-08-01

    Over two decades, the Monte Carlo technique has become a gold standard in simulation of light propagation in turbid media, including biotissues. Technological solutions provide further advances of this technique. The Intel Xeon Phi coprocessor is a new type of accelerator for highly parallel general purpose computing, which allows execution of a wide range of applications without substantial code modification. We present a technical approach of porting our previously developed Monte Carlo (MC) code for simulation of light transport in tissues to the Intel Xeon Phi coprocessor. We show that employing the accelerator allows reducing computational time of MC simulation and obtaining simulation speed-up comparable to GPU. We demonstrate the performance of the developed code for simulation of light transport in the human head and determination of the measurement volume in near-infrared spectroscopy brain sensing. PMID:26249663

  13. Strong-light photoinhibition treatment accelerates the changes of protein secondary structures in triton-treated photosystem I and photosystem II complexes.

    PubMed

    Ruan, X; Xu, Q; Mao, H B; Li, G F; Wei, J; Gong, Y D; Kuang, T Y; Zhao, N M

    2001-04-01

    Changes in the protein secondary structure and electron transport activity of the Triton X-100-treated photosystem I (PSI) and photosystem II (PSII) complexes after strong illumination treatment were studied using Fourier transform-infrared (FT-IR) spectroscopy and an oxygen electrode. Short periods of photoinhibitory treatment led to obvious decreases in the rates of PSI-mediated electron transport activity and PSII-mediated oxygen evolution in the native or Triton-treated PSI and PSII complexes. In the native PSI and PSII complexes, the protein secondary structures had little changes after the photoinhibitory treatment. However, in both Triton-treated PSI and PSII complexes, short photoinhibition times caused significant loss of alpha-helical content and increase of beta-sheet structure, similar to the conformational changes in samples of Triton-treated PSI and PSII complexes after long periods of dark incubation. Our results demonstrate that strong-light treatment to the Triton-treated PSI and PSII complexes accelerates destruction of the transmembrane structure of proteins in the two photosynthetic membranes. PMID:11565905

  14. Real-time dual-mode standard/complex Fourier-domain OCT system using graphics processing unit accelerated 4D signal processing and visualization

    NASA Astrophysics Data System (ADS)

    Zhang, Kang; Kang, Jin U.

    2011-03-01

    We realized a real-time dual-mode standard/complex Fourier-domain optical coherence tomography (FD-OCT) system using graphics processing unit (GPU) accelerated 4D (3D+time) signal processing and visualization. For both standard and complex FD-OCT modes, the signal processing tasks were implemented on a dual-GPUs architecture that included λ-to-k spectral re-sampling, fast Fourier transform (FFT), modified Hilbert transform, logarithmic-scaling, and volume rendering. The maximum A-scan processing speeds achieved are >3,000,000 line/s for the standard 1024-pixel-FD-OCT, and >500,000 line/s for the complex 1024-pixel-FD-OCT. Multiple volumerendering of the same 3D data set were preformed and displayed with different view angles. The GPU-acceleration technique is highly cost-effective and can be easily integrated into most ultrahigh speed FD-OCT systems to overcome the 3D data processing and visualization bottlenecks.

  15. Testing prototypes of high-temperature superconducting current leads of cryogenic stand for testing magnetic elements of the NICA accelerating complex

    NASA Astrophysics Data System (ADS)

    Kres, E. V.; Kadenko, I. N.; Bessheiko, O. A.; Belov, D. V.; Blinov, N. A.; Galimov, A. R.; Zorin, A. G.; Karpinsky, V. N.; Nikiforov, D. N.; Pivin, R. V.; Smirnov, A. V.; Shevchenko, E. V.; Smirnov, S. A.; Khodzhibagiyan, G. G.; Liu, Cheng Lian

    2014-09-01

    In the Laboratory of High Energies at the Joint Institute for Nuclear Research, as part of the NICA-MPD [1] project, tests of two prototypes of HTSC current leads prepared at ASIPP institute (Hefei, China) have been performed [2, 3] to measure electric and heat parameters and to search for structural and physical drawbacks. Based on the experimental results, necessary changes are made in the structure of HTSC current leads of the testing stand for the magnetic element testing of the NICA accelerating complex and its basic setups: the Nuclotron, Booster, and Collider.

  16. On the development of an ion-beam stochastic cooling system for the nuclotron superconducting accelerator complex

    NASA Astrophysics Data System (ADS)

    Kobets, A. G.; Sidorin, A. O.; Trubnikov, G. V.; Shurkhno, N. A.

    2012-07-01

    The Joint Institute for Nuclear Research (JINR) initiated the creation of a unique heavy-ion collider, the Nuclotron-based ion collider facility (NICA), which is planned to be put into commission in 2016. According to the calculation data, the collider luminosity, which should be kept at a record high level of 1027 cm-2 s-1, will gradually decrease, mainly due to intrabeam scattering. To maintain luminosity at a high level, it is necessary to include a cooling system in the base project of the accelerator. Among the two cooling methods (electron and stochastic) most frequently used for heavy ion beams, stochastic cooling seems more attractive. However, there has been a lack of experience in the development and commissioning of such systems in Russia. For this reason, an experiment on stochastic cooling on the Nuclotron accelerator is being prepared to explore the technology and possibilities of this method. In this work, the method of stochastic cooling, the technique for calculating the cooling dynamics, and the experimental setup under development are briefly described.

  17. Amps particle accelerator definition study

    NASA Technical Reports Server (NTRS)

    Sellen, J. M., Jr.

    1975-01-01

    The Particle Accelerator System of the AMPS (Atmospheric, Magnetospheric, and Plasmas in Space) payload is a series of charged particle accelerators to be flown with the Space Transportation System Shuttle on Spacelab missions. In the configuration presented, the total particle accelerator system consists of an energetic electron beam, an energetic ion accelerator, and both low voltage and high voltage plasma acceleration devices. The Orbiter is illustrated with such a particle accelerator system.

  18. Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Sidorin, Anatoly

    2010-01-01

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  19. Linear Accelerators

    SciTech Connect

    Sidorin, Anatoly

    2010-01-05

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  20. Complexation of the vulcanization accelerator tetramethylthiuram disulfide and related molecules with zinc compounds including zinc oxide clusters (Zn4O4).

    PubMed

    Steudel, Ralf; Steudel, Yana; Wong, Ming Wah

    2008-01-01

    Zinc chemicals are used as activators in the vulcanization of organic polymers with sulfur to produce elastic rubbers. In this work, the reactions of Zn(2+), ZnMe(2), Zn(OMe)(2), Zn(OOCMe)(2), and the heterocubane cluster Zn(4)O(4) with the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and with the related radicals and anions Me(2)NCS(2)(*), Me(2)NCS(3)(*), Me(2)NCS(2)(-), and Me(2)NCS(3)(-) have been studied by quantum chemical methods at the MP2/6-31+G(2df,p)//B3LYP/6-31+G* level of theory. More than 35 zinc complexes have been structurally characterized and the energies of formation from their components calculated for the first time. The binding energy of TMTD as a bidendate ligand increases in the order ZnMe(2)complexes with the radicals Me(2)NCS(2)(*) and Me(2)NCS(3)(*). Dissociation of the TMTD molecule at the S-S bond on reaction with the Zn(4)O(4) cluster is predicted to be strongly exothermic, in sharp contrast to the endothermic S-S bond dissociation of the free molecule. The same holds for tetramethylthiuram trisulfide (TMTT). Surprisingly, the resulting complexes contain Zn-S as well as S-O bonds. The Zn(4)O(4) nanocluster serves here as a model for bulk zinc oxide used as an activator in rubber vulcanization by sulfur. The further uptake of sulfur atoms by the various complexes from S(8) or TMTD with formation of species derived from the radical Me(2)NCS(3)(*) or the trithiocarbamate anion Me(2)NCS(3)(-) is endothermic for mono- and dinuclear zinc dithiocarbamate (dtc) complexes such as [Zn(dtc)(2)] and [Zn(2)(dtc)(4)], but exothermic in the case of polynuclear zinc oxide species containing bridging ligands as in [Zn(4)O(4)(mu-S(2)CNMe(2))] and [Zn(4)O(4)(mu-dtc)]. Therefore, zinc oxide as a polynuclear species is predicted to promote the formation of trisulfido complexes, which are generally assumed to serve as catalysts for the transfer of

  1. The problems associated with the monitoring of complex workplace radiation fields at European high-energy accelerators and thermonuclear fusion facilities.

    PubMed

    Bilski, P; Blomgren, J; d'Errico, F; Esposito, A; Fehrenbacher, G; Fernàndez, F; Fuchs, A; Golnik, N; Lacoste, V; Leuschner, A; Sandri, S; Silari, M; Spurny, F; Wiegel, B; Wright, P

    2007-01-01

    The European Commission is funding within its Sixth Framework Programme a three-year project (2005-2007) called CONRAD, COordinated Network for RAdiation Dosimetry. The organisational framework for this project is provided by the European Radiation Dosimetry Group EURADOS. One task within the CONRAD project, Work Package 6 (WP6), was to provide a report outlining research needs and research activities within Europe to develop new and improved methods and techniques for the characterisation of complex radiation fields at workplaces around high-energy accelerators, but also at the next generation of thermonuclear fusion facilities. The paper provides an overview of the report, which will be available as CERN Yellow Report. PMID:17496292

  2. Conceptual design project: Accelerator complex for nuclear physics studies and boron neutron capture therapy application at the Yerevan Physics Institute (YerPhI) Yerevan, Armenia

    NASA Astrophysics Data System (ADS)

    Avagyan, R. H.; Kerobyan, I. A.

    2015-07-01

    The final goal of the proposed project is the creation of a Complex of Accelerator Facilities at the Yerevan Physics Institute (CAF YerPhI) for nuclear physics basic researches, as well as for applied programs including boron neutron capture therapy (BNCT). The CAF will include the following facilities: Cyclotron C70, heavy material (uranium) target/ion source, mass-separator, LINAC1 (0.15-1.5 MeV/u) and LINAC2 (1.5-10 MeV/u). The delivered by C70 proton beams with energy 70 MeV will be used for investigations in the field of basic nuclear physics and with energy 30 MeV for use in applications.

  3. Longitudinal painting with large amplitude second harmonic rf voltages in the rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

    NASA Astrophysics Data System (ADS)

    Tamura, Fumihiko; Yamamoto, Masanobu; Yoshii, Masahito; Ohmori, Chihiro; Nomura, Masahiro; Schnase, Alexander; Toda, Makoto; Suzuki, Hiromitsu; Shimada, Taihei; Hara, Keigo; Hasegawa, Katsushi

    2009-04-01

    In the rapid cycling synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC), the longitudinal painting is important to alleviate the space-charge effects. It is known that the momentum offset injection and applying the second harmonic rf voltage improves the bunching factor, which is defined as the ratio of average and peak current. Our simulation studies show that the large-amplitude second harmonic, 80% to the fundamental, is optimum, and the second harmonic phase sweep improves the bunching factor at the beginning of the injection period. We performed the beam tests of longitudinal painting in the J-PARC RCS. We proved that the longitudinal painting with the 80% second harmonic, the momentum offset of -0.2%, and the second harmonic phase sweep improved bunching factors significantly.

  4. Radiation Safety Systems for Accelerator Facilities

    SciTech Connect

    Liu, James C

    2001-10-17

    The Radiation Safety System (RSS) of an accelerator facility is used to protect people from prompt radiation hazards associated with accelerator operation. The RSS is a fully interlocked, engineered system with a combination of passive and active elements that are reliable, redundant, and fail-safe. The RSS consists of the Access Control System (ACS) and the Radiation Containment System (RCS). The ACS is to keep people away from the dangerous radiation inside the shielding enclosure. The RCS limits and contains the beam/radiation conditions to protect people from the prompt radiation hazards outside the shielding enclosure in both normal and abnormal operations. The complexity of a RSS depends on the accelerator and its operation, as well as associated hazard conditions. The approaches of RSS among different facilities can be different. This report gives a review of the RSS for accelerator facilities.

  5. Radiation Safety Systems for Accelerator Facilities

    SciTech Connect

    James C. Liu; Jeffrey S. Bull; John Drozdoff; Robert May; Vaclav Vylet

    2001-10-01

    The Radiation Safety System (RSS) of an accelerator facility is used to protect people from prompt radiation hazards associated with accelerator operation. The RSS is a fully interlocked, engineered system with a combination of passive and active elements that are reliable, redundant, and fail-safe. The RSS consists of the Access Control System (ACS) and the Radiation Containment System (RCS). The ACS is to keep people away from the dangerous radiation inside the shielding enclosure. The RCS limits and contains the beam/radiation conditions to protect people from the prompt radiation hazards outside the shielding enclosure in both normal and abnormal operations. The complexity of a RSS depends on the accelerator and its operation, as well as associated hazard conditions. The approaches of RSS among different facilities can be different. This report gives a review of the RSS for accelerator facilities.

  6. High binding yet accelerated guest rotation within a cucurbit[7]uril complex. Toward paramagnetic gyroscopes and rolling nanomachines.

    PubMed

    Casano, G; Poulhès, F; Tran, T K; Ayhan, M M; Karoui, H; Siri, D; Gaudel-Siri, A; Rockenbauer, A; Jeschke, G; Bardelang, D; Tordo, P; Ouari, O

    2015-07-28

    The (15-oxo-3,7,11-triazadispiro[5.1.5.3]hexadec-7-yl)oxidanyl, a bis-spiropiperidinium nitroxide derived from TEMPONE, can be included in cucurbit[7]uril to form a strong (K(a)∼ 2 × 10(5) M(-1)) CB[7]@bPTO complex. EPR and MS spectra, DFT calculations, and unparalleled increased resistance (a factor of ∼10(3)) toward ascorbic acid reduction show evidence of deep inclusion of bPTO inside CB[7]. The unusual shape of the CB[7]@bPTO EPR spectrum can be explained by an anisotropic Brownian rotational diffusion, the global tumbling of the complex being slower than rotation of bPTO around its "long molecular axis" inside CB[7]. The CB[7] (stator) with the encapsulated bPTO (rotator) behaves as a supramolecular paramagnetic rotor with increased rotational speed of the rotator that has great potential for advanced nanoscale machines requiring wheels such as cucurbiturils with virtually no friction between the wheel and the axle for optimum wheel rotation (i.e. nanopulleys and nanocars). PMID:26123621

  7. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  8. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

    ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

  9. J-PARC Accelerator

    SciTech Connect

    Yamazaki, Yoshishige

    2008-02-21

    The Japan Proton Accelerator Research Complex (J-PARC) is under construction in Tokai site. The linac beam commissioning started last fall, while the beam commissioning of the 3-GeV Rapid-Cycling Synchrotron (RCS) will start this fall. The status of the J-PARC accelerator is reported with emphasis on the technical development accomplished for the J-PARC.

  10. 2,3,7,8-Tetrachlorodibenzo-p-dioxin increases the expression of genes in the human epidermal differentiation complex and accelerates epidermal barrier formation.

    PubMed

    Sutter, Carrie Hayes; Bodreddigari, Sridevi; Campion, Christina; Wible, Ryan S; Sutter, Thomas R

    2011-11-01

    Chloracne is commonly observed in people exposed to dioxins, yet the mechanism of toxicity is not well understood. The pathology of chloracne is characterized by hyperkeratinization of the interfollicular squamous epithelium, hyperproliferation and hyperkeratinization of hair follicle cells as well as a metaplastic response of the ductular sebum secreting sebaceous glands. In vitro studies using normal human epidermal keratinocytes to model interfollicular human epidermis demonstrate a 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-mediated acceleration of differentiation and increase in gene expression of several prodifferentiation genes, including filaggrin (FLG). Here, we demonstrated that the TCDD-activated aryl hydrocarbon receptor (AHR) bound a small fragment of DNA upstream of the transcriptional start sites of the FLG gene, containing one of two candidate xenobiotic response elements (XREs). Reporter assays using the promoter region of FLG containing the two putative XREs indicated that the increase in this messenger RNA (mRNA) was due to TCDD-mediated enhanced transcription, which was lost when both XREs were mutated. As FLG is part of the human epidermal differentiation complex (EDC) found on chromosome 1, we measured mRNAs from an additional 18 EDC genes for their regulation by TCDD. Of these genes, 14 were increased by TCDD. Immunoblot assays demonstrated that the proteins of FLG as well as that of another prodifferentiation gene, small proline rich protein 2, were increased by TCDD. In utero exposure to TCDD accelerated the formation of the epidermal barrier in the developing mouse fetus by approximately 1 day. These results indicate that the epidermal permeability barrier is a functional target of the TCDD-activated AHR. PMID:21835898

  11. Neighborhood inverse consistency preprocessing

    SciTech Connect

    Freuder, E.C.; Elfe, C.D.

    1996-12-31

    Constraint satisfaction consistency preprocessing methods are used to reduce search effort. Time and especially space costs limit the amount of preprocessing that will be cost effective. A new form of consistency preprocessing, neighborhood inverse consistency, can achieve more problem pruning than the usual arc consistency preprocessing in a cost effective manner. There are two basic ideas: (1) Common forms of consistency enforcement basically operate by identifying and remembering solutions to subproblems for which a consistent value cannot be found for some additional problem variable. The space required for this memory can quickly become prohibitive. Inverse consistency basically operates by removing values for variables that are not consistent with any solution to some subproblem involving additional variables. The space requirement is at worst linear. (2) Typically consistency preprocessing achieves some level of consistency uniformly throughout the problem. A subproblem solution will be tested against each additional variable that constrains any subproblem variable. Neighborhood consistency focuses attention on the subproblem formed by the variables that are all constrained by the value in question. By targeting highly relevant subproblems we hope to {open_quotes}skim the cream{close_quotes}, obtaining a high payoff for a limited cost.

  12. Auroral plasma acceleration processes at Mars

    NASA Astrophysics Data System (ADS)

    Lundin, R.; Barabash, S.; Winningham, D.

    2012-09-01

    Following the first Mars Express (MEX) findings of auroral plasma acceleration above Martian magnetic anomalies[1, 2], a more detailed analysis is carried out regarding the physical processes that leads to plasma acceleration, and how they connect to the dynamo-, and energy source regions. The ultimate energy source for Martian plasma acceleration is the solar wind. The question is, by what mechanisms is solar wind energy and momentum transferred into the magnetic flux tubes that connect to Martian magnetic anomalies? What are the key plasma acceleration processes that lead to aurora and the associated ionospheric plasma outflow from Mars? The experimental setup on MEX limits our capability to carry out "auroral physics" at Mars. However, with knowledge acquired from the Earth, we may draw some analogies with terrestrial auroral physics. Using the limited data set available, consisting of primarily ASPERA and MARSIS data, an interesting picture of aurora at Mars emerges. There are some strong similarities between accelerated/heated electrons and ions in the nightside high altitude region above Mars and the electron/ion acceleration above Terrestrial discrete aurora. Nearly monoenergetic downgoing electrons are observed in conjunction with nearly monoenergetic upgoing ions. Monoenergetic counterstreaming ions and electrons is the signature of plasma acceleration in quasi-static electric fields. However, compared to the Earth's aurora, with auroral process guided by a dipole field, aurora at Mars is expected to form complex patterns in the multipole environment governed by the Martian crustal magnetic field regions. Moreover, temporal/spatial scales are different at Mars. It is therefore of interest to mention another common characteristics that exist for Earth and Mars, plasma acceleration by waves. Low-frequency, Alfvén, waves is a very powerful means of plasma acceleration in the Earth's magnetosphere. Low-frequency waves associated with plasma acceleration

  13. A code for analysis of the fine structure in near-rigid weakly-bonded open-shell complexes that consist of a diatomic radical in a Σ3 state and a closed-shell molecule

    NASA Astrophysics Data System (ADS)

    Fawzy, Wafaa M.

    2010-10-01

    A FORTRAN code is developed for simulation and fitting the fine structure of a planar weakly-bonded open-shell complex that consists of a diatomic radical in a Σ3 electronic state and a diatomic or a polyatomic closed-shell molecule. The program sets up the proper total Hamiltonian matrix for a given J value and takes account of electron-spin-electron-spin, electron-spin rotation interactions, and the quartic and sextic centrifugal distortion terms within the complex. Also, R-dependence of electron-spin-electron-spin and electron-spin rotation couplings are considered. The code does not take account of effects of large-amplitude internal rotation of the diatomic radical within the complex. It is assumed that the complex has a well defined equilibrium geometry so that effects of large amplitude motion are negligible. Therefore, the computer code is suitable for a near-rigid rotor. Numerical diagonalization of the matrix provides the eigenvalues and the eigenfunctions that are necessary for calculating energy levels, frequencies, relative intensities of infrared or microwave transitions, and expectation values of the quantum numbers within the complex. Goodness of all the quantum numbers, with exception of J and parity, depends on relative sizes of the product of the rotational constants and quantum numbers (i.e. BJ, CJ, and AK), electron-spin-electron-spin, and electron-spin rotation couplings, as well as the geometry of the complex. Therefore, expectation values of the quantum numbers are calculated in the eigenfunctions basis of the complex. The computational time for the least squares fits has been significantly reduced by using the Hellman-Feynman theory for calculating the derivatives. The computer code is useful for analysis of high resolution infrared and microwave spectra of a planar near-rigid weakly-bonded open-shell complex that contains a diatomic fragment in a Σ3 electronic state and a closed-shell molecule. The computer program was successfully

  14. Consistent model driven architecture

    NASA Astrophysics Data System (ADS)

    Niepostyn, Stanisław J.

    2015-09-01

    The goal of the MDA is to produce software systems from abstract models in a way where human interaction is restricted to a minimum. These abstract models are based on the UML language. However, the semantics of UML models is defined in a natural language. Subsequently the verification of consistency of these diagrams is needed in order to identify errors in requirements at the early stage of the development process. The verification of consistency is difficult due to a semi-formal nature of UML diagrams. We propose automatic verification of consistency of the series of UML diagrams originating from abstract models implemented with our consistency rules. This Consistent Model Driven Architecture approach enables us to generate automatically complete workflow applications from consistent and complete models developed from abstract models (e.g. Business Context Diagram). Therefore, our method can be used to check practicability (feasibility) of software architecture models.

  15. Crystal structure of a dimerization domain of human Caprin-1: insights into the assembly of an evolutionarily conserved ribonucleoprotein complex consisting of Caprin-1, FMRP and G3BP1.

    PubMed

    Wu, Yuhong; Zhu, Jiang; Huang, Xiaolan; Du, Zhihua

    2016-06-01

    Caprin-1 plays roles in many important biological processes, including cellular proliferation, innate immune response, stress response and synaptic plasticity. Caprin-1 has been implicated in several human diseases, including osteosarcoma, breast cancer, viral infection, hearing loss and neurodegenerative disorders. The functions of Caprin-1 depend on its molecular-interaction network. Direct interactions have been established between Caprin-1 and the fragile X mental retardation protein (FMRP), Ras GAP-activating protein-binding protein 1 (G3BP1) and the Japanese encephalitis virus (JEV) core protein. Here, crystal structures of a fragment (residues 132-251) of Caprin-1, which adopts a novel all-α-helical fold and mediates homodimerization through a substantial interface, are reported. Homodimerization creates a large and highly negatively charged concave surface suggestive of a protein-binding groove. The FMRP-interacting sequence motif forms an integral α-helix in the dimeric Caprin-1 structure in such a way that the binding of FMRP would not disrupt the homodimerization of Caprin-1. Based on insights from the structures and existing biochemical data, the existence of an evolutionarily conserved ribonucleoprotein (RNP) complex consisting of Caprin-1, FMRP and G3BP1 is proposed. The JEV core protein may bind Caprin-1 at the negatively charged putative protein-binding groove and an adjacent E-rich sequence to hijack the RNP complex. PMID:27303792

  16. Radiation from Accelerated Particles in Shocks and Reconnections

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Choi, E. J.; Min, K. W.; Niemiec, J.; Fishman, G. J.; Zhang, B.; Hardee, P.; Mizuno, Y.; Medvedev, M.; Nordlund, A.; Frederiksen, J. T.; Sol, H.; Pohl, M.; Hartmann, D. H.

    2012-01-01

    We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic jets propagating into an unmagnetized plasmas. Strong magnetic fields generated in the trailing shock contribute to the electrons transverse deflection and acceleration. We have calculated, self-consistently, the radiation from electrons accelerated in the turbulent magnetic fields. We found that the synthetic spectra depend on the Lorentz factor of the jet, its thermal temperature and strength of the generated magnetic fields. The properties of the radiation may be important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets in general, and supernova remnants

  17. Indexing Consistency and Quality.

    ERIC Educational Resources Information Center

    Zunde, Pranas; Dexter, Margaret E.

    A measure of indexing consistency is developed based on the concept of 'fuzzy sets'. It assigns a higher consistency value if indexers agree on the more important terms than if they agree on less important terms. Measures of the quality of an indexer's work and exhaustivity of indexing are also proposed. Experimental data on indexing consistency…

  18. Accelerated life testing effects on CMOS microcircuit characteristics

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Accelerated life tests were performed on CMOS microcircuits to predict their long term reliability. The consistency of the CMOS microcircuit activation energy between the range of 125 C to 200 C and the range 200 C to 250 C was determined. Results indicate CMOS complexity and the amount of moisture detected inside the devices after testing influences time to failure of tested CMOS devices.

  19. Dinitrosyl iron complexes with glutathione incorporated into a collagen matrix as a base for the design of drugs accelerating skin wound healing.

    PubMed

    Shekhter, Anatoly B; Rudenko, Tatyana G; Istranov, Leonid P; Guller, Anna E; Borodulin, Rostislav R; Vanin, Anatoly F

    2015-10-12

    Composites of a collagen matrix and dinitrosyl iron complexes with glutathione (DNIC-GS) (in a dose of 4.0 μmoles per item) in the form of spongy sheets (DNIC-Col) were prepared and then topically applied in rat excisional full-thickness skin wound model. The effects of DNIC-Col were studied in comparison with spontaneously healing wounds (SpWH) and wounds treated with collagen sponges (Col) without DNIC-GS. The composites induced statistically and clinically significant acceleration of complete wound closure (21±1 day versus 23±1 day and 26±1 day for DNIC-Col, Col and SpWH, respectively). Histological examination of wound tissues on days 4, 14, 18 and 21 after surgery demonstrated that this improvement was supported by enhanced growth, maturation and fibrous transformation of granulation tissue and earlier epithelization of the injured area in rats treated with DNIC-Col composites benchmarked against Col and SpWH. It is suggested that the positive effect of the new pharmaceutical material on wound healing is based on the release of NO from decomposing DNIC. This effect is believed to be potentiated by the synergy of DNIC and collagen. PMID:26066410

  20. Low-complexity feed-forward carrier phase estimation for M-ary QAM based on phase search acceleration by quadratic approximation.

    PubMed

    Xiang, Meng; Fu, Songnian; Deng, Lei; Tang, Ming; Shum, Perry; Liu, Deming

    2015-07-27

    Blind phase search (BPS) algorithm for M-QAM has excellent tolerance to laser linewidth at the expense of rather high computation complexity (CC). Here, we first theoretically obtain the quadratic relationship between the test angle and corresponding distance matric during the BPS implementation. Afterwards, we propose a carrier phase estimation (CPE) based on a two-stage BPS with quadratic approximation (QA). Instead of searching the phase blindly with fixed step-size for the BPS algorithm, QA can significantly accelerate the speed of phase searching. As a result, a group factor of 2.96/3.05, 4.55/4.67 and 2.27/2.3 (in the form of multipliers/adders) reduction of CC is achieved for 16QAM, 64QAM and 256QAM, respectively, in comparison with the traditional BPS scheme. Meanwhile, a guideline for determining the summing filter block length is put forward during performance optimization. Under the condition of optimum filter block length, our proposed scheme shows similar performance as traditional BPS scheme. At 1 dB required E(S)/N(0) penalty @ BER = 10(-2), our proposed CPE scheme can tolerate a times symbol duration productΔf⋅T(S) of 1.7 × 10(-4), 6 × 10(-5) and 1.5 × 10(-5) for 16/64/256-QAM, respectively. PMID:26367577

  1. Plasma accelerators

    SciTech Connect

    Ruth, R.D.; Chen, P.

    1986-03-01

    In this paper we discuss plasma accelerators which might provide high gradient accelerating fields suitable for TeV linear colliders. In particular we discuss two types of plasma accelerators which have been proposed, the Plasma Beat Wave Accelerator and the Plasma Wake Field Accelerator. We show that the electric fields in the plasma for both schemes are very similar, and thus the dynamics of the driven beams are very similar. The differences appear in the parameters associated with the driving beams. In particular to obtain a given accelerating gradient, the Plasma Wake Field Accelerator has a higher efficiency and a lower total energy for the driving beam. Finally, we show for the Plasma Wake Field Accelerator that one can accelerate high quality low emittance beams and, in principle, obtain efficiencies and energy spreads comparable to those obtained with conventional techniques.

  2. Presentation on a Space Acceleration Measurement System (SAMS)

    NASA Technical Reports Server (NTRS)

    Chase, Theodore L.

    1990-01-01

    The primary objective of the Space Acceleration Measurement Systems (SAMS) project is to provide an acceleration measurement system capable of serving a wide variety of space experiments. The design of the system being developed under this project takes into consideration requirements for experiments located in the middeck, in the orbiter bay, and in Spacelab. In addition to measuring, conditioning, and recording accelerations, the system will be capable of performing complex calculations and interactive control. The main components consist of a remote triaxial optical storage device. In operation, the triaxial sensor head produces output signals in response to acceleration inputs. These signals are preamplified, filtered and converted into digital data which is then transferred to optical memory. The system design is modular, facilitating both software and hardware upgrading as technology advances. Two complete acceleration measurement flight systems will be build and tested under this project.

  3. Consistent interactions and involution

    NASA Astrophysics Data System (ADS)

    Kaparulin, D. S.; Lyakhovich, S. L.; Sharapov, A. A.

    2013-01-01

    Starting from the concept of involution of field equations, a universal method is proposed for constructing consistent interactions between the fields. The method equally well applies to the Lagrangian and non-Lagrangian equations and it is explicitly covariant. No auxiliary fields are introduced. The equations may have (or have no) gauge symmetry and/or second class constraints in Hamiltonian formalism, providing the theory admits a Hamiltonian description. In every case the method identifies all the consistent interactions.

  4. Centrifuge Study of Pilot Tolerance to Acceleration and the Effects of Acceleration on Pilot Performance

    NASA Technical Reports Server (NTRS)

    Creer, Brent Y.; Smedal, Harald A.; Wingrove, Rodney C.

    1960-01-01

    A research program the general objective of which was to measure the effects of various sustained accelerations on the control performance of pilots, was carried out on the Aviation Medical Acceleration Laboratory centrifuge, U.S. Naval Air Development Center, Johnsville, PA. The experimental setup consisted of a flight simulator with the centrifuge in the control loop. The pilot performed his control tasks while being subjected to acceleration fields such as might be encountered by a forward-facing pilot flying an atmosphere entry vehicle. The study was divided into three phases. In one phase of the program, the pilots were subjected to a variety of sustained linear acceleration forces while controlling vehicles with several different sets of longitudinal dynamics. Here, a randomly moving target was displayed to the pilot on a cathode-ray tube. For each combination of acceleration field and vehicle dynamics, pilot tracking accuracy was measured and pilot opinion of the stability and control characteristics was recorded. Thus, information was obtained on the combined effects of complexity of control task and magnitude and direction of acceleration forces on pilot performance. These tests showed that the pilot's tracking performance deteriorated markedly at accelerations greater than about 4g when controlling a lightly damped vehicle. The tentative conclusion was also reached that regardless of the airframe dynamics involved, the pilot feels that in order to have the same level of control over the vehicle, an increase in the vehicle dynamic stability was required with increases in the magnitudes of the acceleration impressed upon the pilot. In another phase, boundaries of human tolerance of acceleration were established for acceleration fields such as might be encountered by a pilot flying an orbital vehicle. A special pilot restraint system was developed to increase human tolerance to longitudinal decelerations. The results of the tests showed that human tolerance

  5. Network Consistent Data Association.

    PubMed

    Chakraborty, Anirban; Das, Abir; Roy-Chowdhury, Amit K

    2016-09-01

    Existing data association techniques mostly focus on matching pairs of data-point sets and then repeating this process along space-time to achieve long term correspondences. However, in many problems such as person re-identification, a set of data-points may be observed at multiple spatio-temporal locations and/or by multiple agents in a network and simply combining the local pairwise association results between sets of data-points often leads to inconsistencies over the global space-time horizons. In this paper, we propose a Novel Network Consistent Data Association (NCDA) framework formulated as an optimization problem that not only maintains consistency in association results across the network, but also improves the pairwise data association accuracies. The proposed NCDA can be solved as a binary integer program leading to a globally optimal solution and is capable of handling the challenging data-association scenario where the number of data-points varies across different sets of instances in the network. We also present an online implementation of NCDA method that can dynamically associate new observations to already observed data-points in an iterative fashion, while maintaining network consistency. We have tested both the batch and the online NCDA in two application areas-person re-identification and spatio-temporal cell tracking and observed consistent and highly accurate data association results in all the cases. PMID:26485472

  6. When is holography consistent?

    NASA Astrophysics Data System (ADS)

    McInnes, Brett; Ong, Yen Chin

    2015-09-01

    Holographic duality relates two radically different kinds of theory: one with gravity, one without. The very existence of such an equivalence imposes strong consistency conditions which are, in the nature of the case, hard to satisfy. Recently a particularly deep condition of this kind, relating the minimum of a probe brane action to a gravitational bulk action (in a Euclidean formulation), has been recognized; and the question arises as to the circumstances under which it, and its Lorentzian counterpart, is satisfied. We discuss the fact that there are physically interesting situations in which one or both versions might, in principle, not be satisfied. These arise in two distinct circumstances: first, when the bulk is not an Einstein manifold and, second, in the presence of angular momentum. Focusing on the application of holography to the quark-gluon plasma (of the various forms arising in the early Universe and in heavy-ion collisions), we find that these potential violations never actually occur. This suggests that the consistency condition is a "law of physics" expressing a particular aspect of holography.

  7. Consistent Quantum Theory

    NASA Astrophysics Data System (ADS)

    Griffiths, Robert B.

    2001-11-01

    Quantum mechanics is one of the most fundamental yet difficult subjects in physics. Nonrelativistic quantum theory is presented here in a clear and systematic fashion, integrating Born's probabilistic interpretation with Schrödinger dynamics. Basic quantum principles are illustrated with simple examples requiring no mathematics beyond linear algebra and elementary probability theory. The quantum measurement process is consistently analyzed using fundamental quantum principles without referring to measurement. These same principles are used to resolve several of the paradoxes that have long perplexed physicists, including the double slit and Schrödinger's cat. The consistent histories formalism used here was first introduced by the author, and extended by M. Gell-Mann, J. Hartle and R. Omnès. Essential for researchers yet accessible to advanced undergraduate students in physics, chemistry, mathematics, and computer science, this book is supplementary to standard textbooks. It will also be of interest to physicists and philosophers working on the foundations of quantum mechanics. Comprehensive account Written by one of the main figures in the field Paperback edition of successful work on philosophy of quantum mechanics

  8. Guidelines for Developing an Academic Acceleration Policy

    ERIC Educational Resources Information Center

    Colangelo, Nicholas; Assouline, Susan G.; Marron, Maureen A.; Castellano, Jaime A.; Clinkenbeard, Pamela R.; Rogers, Karen; Calvert, Eric; Malek, Rosanne; Smith, Donnajo

    2010-01-01

    As an educational intervention, acceleration is decidedly effective for high-ability students. The research support for acceleration that has accumulated over many decades is robust and consistent and allows us to confidently state that carefully planned acceleration decisions are successful. Both grade-based and content-based acceleration are…

  9. Consistent quantum measurements

    NASA Astrophysics Data System (ADS)

    Griffiths, Robert B.

    2015-11-01

    In response to recent criticisms by Okon and Sudarsky, various aspects of the consistent histories (CH) resolution of the quantum measurement problem(s) are discussed using a simple Stern-Gerlach device, and compared with the alternative approaches to the measurement problem provided by spontaneous localization (GRW), Bohmian mechanics, many worlds, and standard (textbook) quantum mechanics. Among these CH is unique in solving the second measurement problem: inferring from the measurement outcome a property of the measured system at a time before the measurement took place, as is done routinely by experimental physicists. The main respect in which CH differs from other quantum interpretations is in allowing multiple stochastic descriptions of a given measurement situation, from which one (or more) can be selected on the basis of its utility. This requires abandoning a principle (termed unicity), central to classical physics, that at any instant of time there is only a single correct description of the world.

  10. Accelerated Reader.

    ERIC Educational Resources Information Center

    Education Commission of the States, Denver, CO.

    This paper provides an overview of Accelerated Reader, a system of computerized testing and record-keeping that supplements the regular classroom reading program. Accelerated Reader's primary goal is to increase literature-based reading practice. The program offers a computer-aided reading comprehension and management program intended to motivate…

  11. HEAVY ION LINEAR ACCELERATOR

    DOEpatents

    Van Atta, C.M.; Beringer, R.; Smith, L.

    1959-01-01

    A linear accelerator of heavy ions is described. The basic contributions of the invention consist of a method and apparatus for obtaining high energy particles of an element with an increased charge-to-mass ratio. The method comprises the steps of ionizing the atoms of an element, accelerating the resultant ions to an energy substantially equal to one Mev per nucleon, stripping orbital electrons from the accelerated ions by passing the ions through a curtain of elemental vapor disposed transversely of the path of the ions to provide a second charge-to-mass ratio, and finally accelerating the resultant stripped ions to a final energy of at least ten Mev per nucleon.

  12. Dielectric assist accelerating structure

    NASA Astrophysics Data System (ADS)

    Satoh, D.; Yoshida, M.; Hayashizaki, N.

    2016-01-01

    A higher-order TM02 n mode accelerating structure is proposed based on a novel concept of dielectric loaded rf cavities. This accelerating structure consists of ultralow-loss dielectric cylinders and disks with irises which are periodically arranged in a metallic enclosure. Unlike conventional dielectric loaded accelerating structures, most of the rf power is stored in the vacuum space near the beam axis, leading to a significant reduction of the wall loss, much lower than that of conventional normal-conducting linac structures. This allows us to realize an extremely high quality factor and a very high shunt impedance at room temperature. A simulation of a 5 cell prototype design with an existing alumina ceramic indicates an unloaded quality factor of the accelerating mode over 120 000 and a shunt impedance exceeding 650 M Ω /m at room temperature.

  13. COMMISSIONING OF THE SPALLATION NEUTRON SOURCE ACCELERATOR SYSTEMS

    SciTech Connect

    Plum, Michael A

    2007-01-01

    The Spallation Neutron Source accelerator complex consists of a 2.5 MeV H- front-end injector system, a 186 MeV normal-conducting linear accelerator, a 1 GeV superconducting linear accelerator, an accumulator ring, and associated beam transport lines. The linac was commissioned in five discrete runs, starting in 2002 and completed in 2005. The accumulator ring and associated beam transport lines were commissioned in two runs from January to April 2006. With the completed commissioning of the SNS accelerator, the facility has begun initial low-power operations. In the course of beam commissioning, most beam performance parameters and beam intensity goals have been achieved at low duty factor. A number of beam dynamics measurements have been performed, including emittance evolution, transverse coupling in the ring, beam instability thresholds, and beam distributions on the target. The commissioning results, achieved beam performance and initial operating experience of the SNS will be discussed

  14. Self-consistent klystron simulations

    SciTech Connect

    Carlsten, B.E.; Tallerico, P.J.

    1985-01-01

    A numerical analysis of large-signal klystron behavior based on general wave-particle interaction theory is presented. The computer code presented is tailored for the minimum amount of complexity needed in klystron simulation. The code includes self-consistent electron motion, space-charge fields, and intermediate and output fields. It also includes use of time periodicity to simplify the problem, accurate representation of the space-charge fields, accurate representation of the cavity standing-wave fields, and a sophisticated particle-pushing routine. In the paper, examples are given that show the effects of cavity detunings, of varying the magnetic field profile, of electron beam asymmetries from the gun, and of variations in external load impedance. 4 refs., 7 figs.

  15. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  16. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  17. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  18. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  19. Muon Acceleration - RLA and FFAG

    SciTech Connect

    Bogacz, Alex

    2011-10-01

    Various acceleration schemes for muons are presented. The overall goal of the acceleration systems: large acceptance acceleration to 25 GeV and 'beam shaping' can be accomplished by various fixed field accelerators at different stages. They involve three superconducting linacs: a single pass linear Pre-accelerator followed by a pair of multi-pass Recirculating Linear Accelerators (RLA) and finally a non-scaling FFAG ring. The present baseline acceleration scenario has been optimized to take maximum advantage of appropriate acceleration scheme at a given stage. The solenoid based Pre-accelerator offers very large acceptance and facilitates correction of energy gain across the bunch and significant longitudinal compression trough induced synchrotron motion. However, far off-crest acceleration reduces the effective acceleration gradient and adds complexity through the requirement of individual RF phase control for each cavity. The RLAs offer very efficient usage of high gradient superconducting RF and ability to adjust path-length after each linac pass through individual return arcs with uniformly periodic FODO optics suitable for chromatic compensation of emittance dilution with sextupoles. However, they require spreaders/recombiners switchyards at both linac ends and significant total length of the arcs. The non-scaling Fixed Field Alternating Gradient (FFAG) ring combines compactness with very large chromatic acceptance (twice the injection energy) and it allows for large number of passes through the RF (at least eight, possibly as high as 15).

  20. Accelerating deactivation

    SciTech Connect

    FISHBACK, K.M.

    1999-02-01

    In recent years, the focus of the U.S. Department of Energy (DOE) complex has shifted from defense production to facility stabilization, decommissioning, and environmental restoration. This shift from production to cleanup requires a parallel shift from operations-focused management to project-focused management for an efficient facility deactivation. In the operation-focused management organization, activities are planned and executed based on production goals and are typically repetitive and cyclic. In the project-focused management environment, activities are based on a defined scope/end objective, start date, and completion date. Since the workforce used to perform production operations is also usually relied onto perform facility deactivation, it is important to shift from an operations management approach to a project management approach. It is best if the transition is accomplished quickly so the project can move forward and workers don't spend a lot of energy anticipating change. Therefore, it is essential that managers, planners, and other workers understand the key elements associated with planning a deactivation project. This paper describes a planning approach that has been used successfully to plan deactivation projects consistent with the requirements provided in DOE Order 430.1A Life Cycle Asset Management and the companion Deactivation Implementation Guide, G430. 1A-3, while exceeding schedule expectations and reducing costs. Although the planning of a deactivation project closely mirrors the classic project planning for construction projects, there are unique variations associated with facility deactivation. The key elements of planning a deactivation project are discussed relative to scope, schedule, and cost. Management tools such as project metrics and histograms are discussed as desired outputs from the planning process. In addition, lessons learned from planning deactivation projects across the DOE complex are discussed relative to making the

  1. Reduction of Acceleration to Effectively Microgravity Levels

    NASA Technical Reports Server (NTRS)

    Downey, James Patton

    2000-01-01

    Pressure gradients, i.e. pressure head, and buoyancy driven convection can be greatly decreased in experimental systems by acceleration of the laboratory reference frame at a rate consistent with the acceleration due to gravity. This may be done in a number of ways, the best known of which is the use of orbiting spacecraft. Other techniques include the use of aircraft following an appropriate parabolic trajectory or drop towers. The result is an experimental condition in which fluids experience virtually no outside forces relative to the laboratory reference frame. Such conditions are appropriate for the study of processes with diffusion dominated heat and/or mass Under, the study of phase transitions in the absence of pressure gradients, the study of solutal or thermal capillary convection, or containerless processes. Ways of achieving these conditions and complexities that arise in performing experiments in this environment are discussed.

  2. Microwave inverse Cerenkov accelerator

    SciTech Connect

    Zhang, T.B.; Marshall, T.C.; LaPointe, M.A.; Hirshfield, J.L.

    1997-03-01

    A Microwave Inverse Cerenkov Accelerator (MICA) is currently under construction at the Yale Beam Physics Laboratory. The accelerating structure in MICA consists of an axisymmetric dielectrically lined waveguide. For the injection of 6 MeV microbunches from a 2.856 GHz RF gun, and subsequent acceleration by the TM{sub 01} fields, particle simulation studies predict that an acceleration gradient of 6.3 MV/m can be achieved with a traveling-wave power of 15 MW applied to the structure. Synchronous injection into a narrow phase window is shown to allow trapping of all injected particles. The RF fields of the accelerating structure are shown to provide radial focusing, so that longitudinal and transverse emittance growth during acceleration is small, and that no external magnetic fields are required for focusing. For 0.16 nC, 5 psec microbunches, the normalized emittance of the accelerated beam is predicted to be less than 5{pi}mm-mrad. Experiments on sample alumina tubes have been conducted that verify the theoretical dispersion relation for the TM{sub 01} mode over a two-to-one range in frequency. No excitation of axisymmetric or non-axisymmetric competing waveguide modes was observed. High power tests showed that tangential electric fields at the inner surface of an uncoated sample of alumina pipe could be sustained up to at least 8.4 MV/m without breakdown. These considerations suggest that a MICA test accelerator can be built to examine these predictions using an available RF power source, 6 MeV RF gun and associated beam line. {copyright} {ital 1997 American Institute of Physics.}

  3. Accelerated molecular dynamics methods

    SciTech Connect

    Perez, Danny

    2011-01-04

    The molecular dynamics method, although extremely powerful for materials simulations, is limited to times scales of roughly one microsecond or less. On longer time scales, dynamical evolution typically consists of infrequent events, which are usually activated processes. This course is focused on understanding infrequent-event dynamics, on methods for characterizing infrequent-event mechanisms and rate constants, and on methods for simulating long time scales in infrequent-event systems, emphasizing the recently developed accelerated molecular dynamics methods (hyperdynamics, parallel replica dynamics, and temperature accelerated dynamics). Some familiarity with basic statistical mechanics and molecular dynamics methods will be assumed.

  4. High intensity hadron accelerators

    SciTech Connect

    Teng, L.C.

    1989-05-01

    This rapporteur report consists mainly of two parts. Part I is an abridged review of the status of all High Intensity Hadron Accelerator projects in the world in semi-tabulated form for quick reference and comparison. Part II is a brief discussion of the salient features of the different technologies involved. The discussion is based mainly on my personal experiences and opinions, tempered, I hope, by the discussions I participated in in the various parallel sessions of the workshop. In addition, appended at the end is my evaluation and expression of the merits of high intensity hadron accelerators as research facilities for nuclear and particle physics.

  5. Stochastic modeling of Lagrangian accelerations

    NASA Astrophysics Data System (ADS)

    Reynolds, Andy

    2002-11-01

    It is shown how Sawford's second-order Lagrangian stochastic model (Phys. Fluids A 3, 1577-1586, 1991) for fluid-particle accelerations can be combined with a model for the evolution of the dissipation rate (Pope and Chen, Phys. Fluids A 2, 1437-1449, 1990) to produce a Lagrangian stochastic model that is consistent with both the measured distribution of Lagrangian accelerations (La Porta et al., Nature 409, 1017-1019, 2001) and Kolmogorov's similarity theory. The later condition is found not to be satisfied when a constant dissipation rate is employed and consistency with prescribed acceleration statistics is enforced through fulfilment of a well-mixed condition.

  6. Acceleration Studies

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.

    1993-01-01

    Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

  7. The APT Accelerator.*

    NASA Astrophysics Data System (ADS)

    Lawrence, George P.

    1996-05-01

    The accelerator for the Accelerator Production of Tritium (APT) project is a high-power RF linac designed to produce a 100-mA CW proton beam at an energy of 1300 MeV. A heavy-metal target produces large quantities of spallation neutrons, which are slowed to thermal energies and captured in a feed material to make tritium. The baseline accelerator design consists of a 75-keV proton injector, a 7-MeV radio-frequency quadrupole (RFQ), a 100-MeV coupled-cavity drift-tube linac (CCDTL), and a 1300-MeV side-coupled linac (SCL). The RFQ operates at a frequency of 350 MHz, while the CCDTL and SCL operate at 700-MHz. A quadrupole-magnet transport system conveys the 1300-MeV beam to production target/blanket assemblies where beam expanders using non-linear magnetic elements transform the linac output distribution into large-area rectangular distributions having a nearly uniform density. All the linac accelerating structures use conventional water-cooled copper technology. The SCL section is based on the well-proven 800-MeV LANSCE high-duty-factor linac at Los Alamos. The CCDTL is a new hybrid accelerating structure that combines the best features of the conventional drift-tube linac and the coupled-cavity linac to provide efficient and stable acceleration in the intermediate velocity range. Approximately 263 1-MW CW klystrons are needed to drive the 130-MW proton beam. The total ac-power requirement for the APT plant is about 438 MW, most of which is needed for the accelerator. An advanced-technology option is being considered that would replace the conventional SCL with a superconducting RF linac composed of sequences of 4-cell elliptical-type cavities. This option would reduce the electric power consumption significantly and would provide increased operational flexibility. * Work supported by the US Department of Energy.

  8. Plasma accelerator

    DOEpatents

    Wang, Zhehui; Barnes, Cris W.

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  9. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  10. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  11. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  12. Dielectric laser accelerators

    NASA Astrophysics Data System (ADS)

    England, R. Joel; Noble, Robert J.; Bane, Karl; Dowell, David H.; Ng, Cho-Kuen; Spencer, James E.; Tantawi, Sami; Wu, Ziran; Byer, Robert L.; Peralta, Edgar; Soong, Ken; Chang, Chia-Ming; Montazeri, Behnam; Wolf, Stephen J.; Cowan, Benjamin; Dawson, Jay; Gai, Wei; Hommelhoff, Peter; Huang, Yen-Chieh; Jing, Chunguang; McGuinness, Christopher; Palmer, Robert B.; Naranjo, Brian; Rosenzweig, James; Travish, Gil; Mizrahi, Amit; Schachter, Levi; Sears, Christopher; Werner, Gregory R.; Yoder, Rodney B.

    2014-10-01

    The use of infrared lasers to power optical-scale lithographically fabricated particle accelerators is a developing area of research that has garnered increasing interest in recent years. The physics and technology of this approach is reviewed, which is referred to as dielectric laser acceleration (DLA). In the DLA scheme operating at typical laser pulse lengths of 0.1 to 1 ps, the laser damage fluences for robust dielectric materials correspond to peak surface electric fields in the GV /m regime. The corresponding accelerating field enhancement represents a potential reduction in active length of the accelerator between 1 and 2 orders of magnitude. Power sources for DLA-based accelerators (lasers) are less costly than microwave sources (klystrons) for equivalent average power levels due to wider availability and private sector investment. Because of the high laser-to-particle coupling efficiency, required pulse energies are consistent with tabletop microJoule class lasers. Combined with the very high (MHz) repetition rates these lasers can provide, the DLA approach appears promising for a variety of applications, including future high-energy physics colliders, compact light sources, and portable medical scanners and radiative therapy machines.

  13. Overview of Accelerator Applications in Energy

    NASA Astrophysics Data System (ADS)

    Garnett, Robert W.; Sheffield, Richard L.

    An overview of the application of accelerators and accelerator technology in energy is presented. Applications span a broad range of cost, size, and complexity and include large-scale systems requiring high-power or high-energy accelerators to drive subcritical reactors for energy production or waste transmutation, as well as small-scale industrial systems used to improve oil and gas exploration and production. The enabling accelerator technologies will also be reviewed and future directions discussed.

  14. Accelerator simulation using computers

    SciTech Connect

    Lee, M.; Zambre, Y.; Corbett, W.

    1992-01-01

    Every accelerator or storage ring system consists of a charged particle beam propagating through a beam line. Although a number of computer programs exits that simulate the propagation of a beam in a given beam line, only a few provide the capabilities for designing, commissioning and operating the beam line. This paper shows how a multi-track'' simulation and analysis code can be used for these applications.

  15. Accelerator simulation using computers

    SciTech Connect

    Lee, M.; Zambre, Y.; Corbett, W.

    1992-01-01

    Every accelerator or storage ring system consists of a charged particle beam propagating through a beam line. Although a number of computer programs exits that simulate the propagation of a beam in a given beam line, only a few provide the capabilities for designing, commissioning and operating the beam line. This paper shows how a ``multi-track`` simulation and analysis code can be used for these applications.

  16. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  17. Self-consistent flattened isochrones

    NASA Astrophysics Data System (ADS)

    Binney, James

    2014-05-01

    We present a family of self-consistent axisymmetric stellar systems that have analytic distribution functions (DFs) of the form f(J), so they depend on three integrals of motion and have triaxial velocity ellipsoids. The models, which are generalizations of Hénon's isochrone sphere, have four dimensionless parameters, two determining the part of the DF that is even in Lz and two determining the odd part of the DF (which determines the azimuthal velocity distribution). Outside their cores, the velocity ellipsoids of all models tend to point to the model's centre, and we argue that this behaviour is generic, so near the symmetry axis of a flattened model, the long axis of the velocity ellipsoid is naturally aligned with the symmetry axis and not perpendicular to it as in many published dynamical models of well-studied galaxies. By varying one of the DF parameters, the intensity of rotation can be increased from zero up to a maximum value set by the requirement that the DF be non-negative. Since angle-action coordinates are easily computed for these models, they are ideally suited for perturbative treatments and stability analysis. They can also be used to choose initial conditions for an N-body model that starts in perfect equilibrium, and to model observations of early-type galaxies. The modelling technique introduced here is readily extended to different radial density profiles, more complex kinematics and multicomponent systems. A number of important technical issues surrounding the determination of the models' observable properties are explained in two appendices.

  18. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  19. Miniature Swine for Preclinical Modeling of Complexities of Human Disease for Translational Scientific Discovery and Accelerated Development of Therapies and Medical Devices.

    PubMed

    Schomberg, Dominic T; Tellez, Armando; Meudt, Jennifer J; Brady, Dane A; Dillon, Krista N; Arowolo, Folagbayi K; Wicks, Joan; Rousselle, Serge D; Shanmuganayagam, Dhanansayan

    2016-04-01

    Noncommunicable diseases, including cardiovascular disease, diabetes, chronic respiratory disease, and cancer, are the leading cause of death in the world. The cost, both monetary and time, of developing therapies to prevent, treat, or manage these diseases has become unsustainable. A contributing factor is inefficient and ineffective preclinical research, in which the animal models utilized do not replicate the complex physiology that influences disease. An ideal preclinical animal model is one that responds similarly to intrinsic and extrinsic influences, providing high translatability and concordance of preclinical findings to humans. The overwhelming genetic, anatomical, physiological, and pathophysiological similarities to humans make miniature swine an ideal model for preclinical studies of human disease. Additionally, recent development of precision gene-editing tools for creation of novel genetic swine models allows the modeling of highly complex pathophysiology and comorbidities. As such, the utilization of swine models in early research allows for the evaluation of novel drug and technology efficacy while encouraging redesign and refinement before committing to clinical testing. This review highlights the appropriateness of the miniature swine for modeling complex physiologic systems, presenting it as a highly translational preclinical platform to validate efficacy and safety of therapies and devices. PMID:26839324

  20. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  1. Efficient particle acceleration in shocks

    NASA Astrophysics Data System (ADS)

    Heavens, A. F.

    1984-10-01

    A self-consistent non-linear theory of acceleration of particles by shock waves is developed, using an extension of the two-fluid hydrodynamical model by Drury and Völk. The transport of the accelerated particles is governed by a diffusion coefficient which is initially assumed to be independent of particle momentum, to obtain exact solutions for the spectrum. It is found that steady-state shock structures with high acceleration efficiency are only possible for shocks with Mach numbers less than about 12. A more realistic diffusion coefficient is then considered, and this maximum Mach number is reduced to about 6. The efficiency of the acceleration process determines the relative importance of the non-relativistic and relativistic particles in the distribution of accelerated particles, and this determines the effective specific heat ratio.

  2. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  3. Acceleration during magnetic reconnection

    SciTech Connect

    Beresnyak, Andrey; Li, Hui

    2015-07-16

    The presentation begins with colorful depictions of solar x-ray flares and references to pulsar phenomena. Plasma reconnection is complex, could be x-point dominated or turbulent, field lines could break due to either resistivity or non-ideal effects, such as electron pressure anisotropy. Electron acceleration is sometimes observed, and sometimes not. One way to study this complex problem is to have many examples of the process (reconnection) and compare them; the other way is to simplify and come to something robust. Ideal MHD (E=0) turbulence driven by magnetic energy is assumed, and the first-order acceleration is sought. It is found that dissipation in big (length >100 ion skin depths) current sheets is universal and independent on microscopic resistivity and the mean imposed field; particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. One example of such flow is spontaneous reconnection. This explains hot electrons with a power-law tail in solar flares, as well as ultrashort time variability in some astrophysical sources.

  4. Occupational exposure to complex mixtures of volatile organic compounds in ambient air: desorption from activated charcoal using accelerated solvent extraction can replace carbon disulfide?

    PubMed

    Fabrizi, Giovanni; Fioretti, Marzia; Rocca, Lucia Mainero

    2013-01-01

    A desorption study of 57 volatile organic compounds (VOCs) has been conducted by use of accelerated solvent extraction (ASE) and gas chromatography-mass spectrometry. Different solvents were tested to extract activated charcoal tubes with the objective of replacing carbon disulfide, used in official methods, because of its highly toxic health and environmental effects. Extraction conditions, for example temperature and number of cycles, were investigated and optimized. The definitive extraction procedure selected was use of acetone at 150 °C and two consecutive extraction cycles at a pressure of 1,500 psi. Considering a sample volume of 0.005 Nm(3), corresponding to a sampling time of 8 h at a flow rate of 0.01 L min(-1), the method was validated over the concentration range 65-26,300 μg Nm(-3). The lowest limit of quantification was 6 μg Nm(-3), and recovery for the 93 % of analytes ranged from 65 to 102 %. For most of the compounds, relative standard deviations were less than 15 % for inter and intra-day precision. Uncertainty of measurement was also determined: the relative expanded uncertainty was always below 29.6 %, except for dichlorodifluoromethane. This work shows that use of friendlier solvent, for example acetone, coupled with use of ASE, can replace use of CS(2) for chemical removal of VOCs from activated charcoal. ASE has several advantages over traditional solvent-extraction methods, including shorter extraction time, minimum sample manipulation, high reproducibility, and less extraction discrimination. No loss of sensitivity occurs and there is also a salutary effect on bench workers' health and on the smell of laboratory air. PMID:22968683

  5. Radiation from Shock-Accelerated Particles

    NASA Technical Reports Server (NTRS)

    Nishikawa, Ken-ichi; Choi, E. J.; Min, K. W.; Niemiec, J.; Zhang, B.; Hardee, P.; Mizuno, Y.; Medvedev, M.; Nordlund, A.; Frederiksen, J.; Sol, H.; Pohl, M.; Hartmann, D. H.; Fishman, G. J.

    2012-01-01

    Plasma instabilities excited in collisionless shocks are responsible for particle acceleration, generation of magnetic fields , and associated radiation. We have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic jet propagating into an unmagnetized plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. The shock structure depends on the composition of the jet and ambient plasma (electron-positron or electron-ions). Strong electromagnetic fields are generated in the reverse , jet shock and provide an emission site. These magnetic fields contribute to the electron's transverse deflection behind the shock. We have calculated, self-consistently, the radiation from electrons accelerated in the turbulent magnetic fields. We found that the synthetic spectra depend on the Lorentz factor of the jet, its thermal temperature and strength of the generated magnetic fields. The detailed properties of the radiation are important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jet shocks, and supernova remnants

  6. Rare Kaon Decays, KEK experiment E391 and E14 at the Japan Physics and Accelerator Research Complex (J-PARC)

    SciTech Connect

    Wah, Yau Wai

    2012-12-06

    The goal of the J-PARC neutral kaon experiment (E14/KOTO) is to discover and measure the rate of the kaon rare decay to pi-zero and two neutrinos. This flavor changing neutral current decay proceeds through second-order weak interactions. Other, as yet undiscovered particles, which can mediate the decay could provide an enhancement (or depletion) to the branching ratio which in the Standard Model is accurately predicted within a few percent to be 2.8x10-11. The experiment is designed to observe more than 100 events at the Standard Model branching. It is a follow-up of the KEK E391a experiment and has stage-2 approval by J-PARC PAC in 2007. E14/KOTO has collaborators from Japan (Kyoto, Osaka, Yamagata, Saga), US (Arizona State, Chicago, Michigan Ann Arbor), Taiwan (National Taiwan), Korea, and Russia (Dubna). The experiment exploits the 300kW 30-50 GeV proton delivery of the J-PARC accelerator with a hermetic high acceptance detector with a fine grained Cesium Iodide (CsI) crystal calorimeter, and state of the art electronic front end and data acquisition system. With the recovery of the tsunami disaster on March 11th 2011, E14 is scheduled to start collecting data in December 2012. During the detector construction phase, Chicago focuses on the front end electronics readout of the entire detector system, particularly the CsI calorimeter. The CsI crystals together with its photomultipliers were previously used at the Fermilab KTeV experiment (E832/E799), and were loaned to E14 via this Chicago DOE support. The new readout electronics includes an innovative 10-pole pulse-shaping technique coupled with high speed digitization (14-bit 125MHz and 12-bit 500MHz). This new instrument enables us to measure both energy and timing, particularly with timing resolution better than 100 psec. Besides the cost saving by elimination of the standard time to digital converters, it is now possible to measure the momenta of the final state photons for additional background suppression

  7. EM Structure Based and Vacuum Acceleration

    SciTech Connect

    Colby, E.R.; /SLAC

    2005-09-27

    The importance of particle acceleration may be judged from the number of applications which require some sort of accelerated beam. In addition to accelerator-based high energy physics research, non-academic applications include medical imaging and treatment, structural biology by x-ray diffraction, pulse radiography, cargo inspection, material processing, food and medical instrument sterilization, and so on. Many of these applications are already well served by existing technologies and will profit only marginally from developments in accelerator technology. Other applications are poorly served, such as structural biology, which is conducted at synchrotron radiation facilities, and medical treatment using proton accelerators, the machines for which are rare because they are complex and costly. Developments in very compact, high brightness and high gradient accelerators will change how accelerators are used for such applications, and potentially enable new ones. Physical and technical issues governing structure-based and vacuum acceleration of charged particles are reviewed, with emphasis on practical aspects.

  8. Accelerator research studies

    SciTech Connect

    Not Available

    1992-01-01

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the first year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams, TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams; TASK C, Study of a Gyroklystron High-power Microwave Source for Linear Colliders. In this report we document the progress that has been made during the past year for each of the three tasks.

  9. Accelerator research studies

    SciTech Connect

    Not Available

    1993-01-01

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the second year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams,'' (P.I., M. Reiser); TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams,'' (Co-P.I.'s, W.W. Destler, M. Reiser, M.J. Rhee, and C.D. Striffler); TASK C, Study of a Gyroklystron High-Power Microwave Source for Linear Colliders,'' (Co-P.I.'s, V.L. Granatstein, W. Lawson, M. Reiser, and C.D. Striffler). In this report we document the progress that has been made during the past year for each of the three tasks.

  10. Hugoniot analysis of the ram accelerator

    NASA Astrophysics Data System (ADS)

    Knowlen, C.; Bruckner, A. P.

    The thermodynamic properties of a combustible propellant gas, after it has been processed by a ram accelerator propulsive mode, are related by a 'ram accelerator Hugoniot' expression. These end states are determined from the 1-D conservation equations in a manner similar to that used for detonation waves, but with the addition of a force term in the momentum equation. Establishment of a region of potentially accessible thermodynamic end states that are consistent with ram accelerator operation at and above the Chapman-Jouguet detonation speed indicates that there are no fundamental constraints on accelerating projectiles over a wide range of Mach numbers in a single propellant mixture. Interpreting experimental data in the context of a generalized ram accelerator process leads to relatively simple propulsive models which can predict the projectile acceleration of any propulsive mode. The projectile velocity and acceleration histories determined by the Hugoniot analysis for the thermally choked ram accelerator mode are in excellent agreement with experiments.

  11. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  12. Attention's Accelerator.

    PubMed

    Reinhart, Robert M G; McClenahan, Laura J; Woodman, Geoffrey F

    2016-06-01

    How do people get attention to operate at peak efficiency in high-pressure situations? We tested the hypothesis that the general mechanism that allows this is the maintenance of multiple target representations in working and long-term memory. We recorded subjects' event-related potentials (ERPs) indexing the working memory and long-term memory representations used to control attention while performing visual search. We found that subjects used both types of memories to control attention when they performed the visual search task with a large reward at stake, or when they were cued to respond as fast as possible. However, under normal circumstances, one type of target memory was sufficient for slower task performance. The use of multiple types of memory representations appears to provide converging top-down control of attention, allowing people to step on the attentional accelerator in a variety of high-pressure situations. PMID:27056975

  13. A role for the FtsQLB complex in cytokinetic ring activation revealed by an ftsL allele that accelerates division

    PubMed Central

    Tsang, Mary-Jane; Bernhardt, Thomas G.

    2015-01-01

    SUMMARY The cytokinetic apparatus of bacteria is initially formed by the polymerization of the tubulin-like FtsZ protein into a ring structure at midcell. This so-called Z-ring facilitates the recruitment of many additional proteins to the division site to form the mature divisome machine. Although the assembly pathway leading to divisome formation has been well characterized, the mechanisms that trigger cell constriction remain unclear. In this report, we study a “forgotten” allele of ftsL from Escherichia coli, which encodes a conserved division gene of unknown function. We discovered that this allele promotes the premature initiation of cell division. Further analysis also revealed that the mutant bypasses the requirement for the essential division proteins ZipA, FtsK, and FtsN and partially bypasses the need for FtsA. These findings suggest that rather than serving simply as a protein scaffold within the divisome, FtsL may play a more active role in the activation of the machine. Our results support a model in which FtsL, along with its partners FtsB and FtsQ, function as part of a sensing mechanism that promotes the onset of cell wall remodeling processes needed for the initiation of cell constriction once assembly of the divisome complex is deemed complete. PMID:25496050

  14. Radiation from Accelerated Particles in Shocks and Reconnections

    NASA Technical Reports Server (NTRS)

    Nishikawa, K. I.; Choi, E. J.; Min, K. W.; Niemiec, J.; Zhang, B.; Hardee, P.; Mizuno, Y.; Medvedev, M.; Nordlund, A.; Frederiksen, J.; Sol, H.; Pohl, M.; Hartmann, D. H.; Fishman, G. J.

    2012-01-01

    Plasma instabilities are responsible not only for the onset and mediation of collisionless shocks but also for the associated acceleration of particles. We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. These magnetic fields contribute to the electrons transverse deflection and, more generally, relativistic acceleration behind the shock. We have calculated, self-consistently, the radiation from electrons accelerated in the turbulent magnetic fields. We found that the synthetic spectra depend on the Lorentz factor of the jet, its thermal temperature and strength of the generated magnetic fields. Our initial results of a jet-ambient interaction with anti-parallelmagnetic fields show pile-up of magnetic fields at the colliding shock, which may lead to reconnection and associated particle acceleration. We will investigate the radiation in a transient stage as a possible generation mechanism of precursors of prompt emission. In our simulations we calculate the radiation from electrons in the shock region. The detailed properties of this radiation are important for understanding the complex time evolution and spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  15. Consistency check of photon beam physical data after recommissioning process

    NASA Astrophysics Data System (ADS)

    Kadman, B.; Chawapun, N.; Ua-apisitwong, S.; Asakit, T.; Chumpu, N.; Rueansri, J.

    2016-03-01

    In radiotherapy, medical linear accelerator (Linac) is the key system used for radiation treatments delivery. Although, recommissioning was recommended after major modification of the machine by AAPM TG53, but it might not be practical in radiotherapy center with heavy workloads. The main purpose of this study was to compare photon beam physical data between initial commissioning and recommissioning of 6 MV Elekta Precise linac. The parameters for comparing were the percentage depth dose (PDD) and beam profiles. The clinical commissioning test cases followed IAEA-TECDOC-1583 were planned on REF 91230 IMRT Dose Verification Phantom by Philips’ Pinnacle treatment planning system. The Delta4PT was used for dose distribution verification with 90% passing criteria of the gamma index (3%/3mm). Our results revealed that the PDDs and beam profiles agreed within a tolerance limit recommended by TRS430. Most of the point doses and dose distribution verification passed the acceptance criteria. This study showed the consistency of photon beam physical data after recommissioning process. There was a good agreement between initial commissioning and recommissioning within a tolerance limit, demonstrated that the full recommissioning process might not be required. However, in the complex treatment planning geometry, the initial data should be applied with great caution.

  16. Sinorhizobium meliloti CheA Complexed with CheS Exhibits Enhanced Binding to CheY1, Resulting in Accelerated CheY1 Dephosphorylation

    PubMed Central

    Dogra, Gaurav; Purschke, Frauke G.; Wagner, Verena; Haslbeck, Martin; Kriehuber, Thomas; Hughes, Jonathan G.; Van Tassell, Maxwell L.; Gilbert, Crystal; Niemeyer, Melanie; Ray, W. Keith; Helm, Richard F.

    2012-01-01

    Retrophosphorylation of the histidine kinase CheA in the chemosensory transduction chain is a widespread mechanism for efficient dephosphorylation of the activated response regulator. First discovered in Sinorhizobium meliloti, the main response regulator CheY2-P shuttles its phosphoryl group back to CheA, while a second response regulator, CheY1, serves as a sink for surplus phosphoryl groups from CheA-P. We have identified a new component in this phospho-relay system, a small 97-amino-acid protein named CheS. CheS has no counterpart in enteric bacteria but revealed distinct similarities to proteins of unknown function in other members of the α subgroup of proteobacteria. Deletion of cheS causes a phenotype similar to that of a cheY1 deletion strain. Fluorescence microscopy revealed that CheS is part of the polar chemosensory cluster and that its cellular localization is dependent on the presence of CheA. In vitro binding, as well as coexpression and copurification studies, gave evidence of CheA/CheS complex formation. Using limited proteolysis coupled with mass spectrometric analyses, we defined CheA163–256 to be the CheS binding domain, which overlaps with the N-terminal part of the CheY2 binding domain (CheA174–316). Phosphotransfer experiments using isolated CheA-P showed that dephosphorylation of CheY1-P but not CheY2-P is increased in the presence of CheS. As determined by surface plasmon resonance spectroscopy, CheY1 binds ∼100-fold more strongly to CheA/CheS than to CheA. We propose that CheS facilitates signal termination by enhancing the interaction of CheY1 and CheA, thereby promoting CheY1-P dephosphorylation, which results in a more efficient drainage of the phosphate sink. PMID:22194454

  17. Quantifying the Consistency of Scientific Databases

    PubMed Central

    Šubelj, Lovro; Bajec, Marko; Mileva Boshkoska, Biljana; Kastrin, Andrej; Levnajić, Zoran

    2015-01-01

    Science is a social process with far-reaching impact on our modern society. In recent years, for the first time we are able to scientifically study the science itself. This is enabled by massive amounts of data on scientific publications that is increasingly becoming available. The data is contained in several databases such as Web of Science or PubMed, maintained by various public and private entities. Unfortunately, these databases are not always consistent, which considerably hinders this study. Relying on the powerful framework of complex networks, we conduct a systematic analysis of the consistency among six major scientific databases. We found that identifying a single "best" database is far from easy. Nevertheless, our results indicate appreciable differences in mutual consistency of different databases, which we interpret as recipes for future bibliometric studies. PMID:25984946

  18. Bio-nano complexes of ZVFeNPs/Fe-s-M13 and Cd (II)/Cd-s-M13 accelerate Cd (II) reduction by FeNPs through dual dispersing and separate deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Shuai; Nakano, Kazuhiko; Yu, Huimin; Shen, Zhongyao

    2014-03-01

    Reduction of Cd (II) in liquor by solid zero valent Fe nanoparticles (ZVFeNPs) is a liquid-solid biphasic reaction in which the reduction efficiency was often lowered by either aggregation of ZVFeNPs or coating of the generated ZVCd. In light of the filamentous nanostructure of bacteriophage M13 with ˜2700 copies of pVIII protein in delicate distribution at the coat, a novel dual dispersing reduction route was designed by introducing two different kinds of M13 with Fe-binding specificity (Fe-s-M13) and Cd-binding specificity (Cd-s-M13) to disperse ZVFeNPs and Cd (II) ions, respectively. The Fe-s-M13 was used for synthesis of the ZVFeNPs/Fe-s-M13 complex, where ZVFeNPs were uniformly dispersed into small nanoparticles (5-10 nm) on Fe-s-M13. The engineered Cd-s-M13, constructed by genetic recombination of pVIII through inserting the gene of a biopanned 7-mer Cd-specific peptide (SCPICPG) into the N-terminus of pVIII gene, was used for Cd (II) dispersion before reduction. The dispersed complex of Cd(II)/Cd-s-M13 was rapidly reduced by complex of ZVFeNPs/Fe-s-M13. Kinetics results showed that the initial reduction rate and final reduction ratio of Cd (II) increased by 35.7% and 16.4%, respectively, through dispersion of ZVFeNPs by Fe-s-M13; they improved again by 53.6% and 37.0%, respectively, through further dispersion of Cd (II) by Cd-s-M13. TEM and EDS results revealed that the acceleration effect of the dual dispersing reduction was arising from uniform dispersion of the small ZVFeNPs and separate deposition of the reduced ZVCd on the two different M13 phages.

  19. Electrostatic Plasma Accelerator (EPA)

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Aston, Graeme

    1995-01-01

    The application of electric propulsion to communications satellites, however, has been limited to the use of hydrazine thrusters with electric heaters for thrust and specific impulse augmentation. These electrothermal thrusters operate at specific impulse levels of approximately 300 s with heater powers of about 500 W. Low power arcjets (1-3 kW) are currently being investigated as a way to increase specific impulse levels to approximately 500 s. Ion propulsion systems can easily produce specific impulses of 3000 s or greater, but have yet to be applied to communications satellites. The reasons most often given for not using ion propulsion systems are their high level of overall complexity, low thrust with long burn times, and the difficulty of integrating the propulsion system into existing commercial spacecraft busses. The Electrostatic Plasma Accelerator (EPA) is a thruster concept which promises specific impulse levels between low power arcjets and those of the ion engine while retaining the relative simplicity of the arcjet. The EPA thruster produces thrust through the electrostatic acceleration of a moderately dense plasma. No accelerating electrodes are used and the specific impulse is a direct function of the applied discharge voltage and the propellant atomic mass.

  20. Consistency, Markedness and Language Change: On the Notion 'Consistent Language.'

    ERIC Educational Resources Information Center

    Smith, N. V.

    1981-01-01

    Explores markedness of languages and language change in relation to their roles in the consistency of language. Concludes typology provides no explanations in itself, but rather through data which need explanations and form a testing ground for linguistic theories. (Author/BK)

  1. Acceleration modules in linear induction accelerators

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Heng; Deng, Jian-Jun

    2014-05-01

    The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

  2. Proton Acceleration at Oblique Shocks

    NASA Astrophysics Data System (ADS)

    Galinsky, V. L.; Shevchenko, V. I.

    2011-06-01

    Acceleration at the shock waves propagating oblique to the magnetic field is studied using a recently developed theoretical/numerical model. The model assumes that resonant hydromagnetic wave-particle interaction is the most important physical mechanism relevant to motion and acceleration of particles as well as to excitation and damping of waves. The treatment of plasma and waves is self-consistent and time dependent. The model uses conservation laws and resonance conditions to find where waves will be generated or damped, and hence particles will be pitch-angle-scattered. The total distribution is included in the model and neither introduction of separate population of seed particles nor some ad hoc escape rate of accelerated particles is needed. Results of the study show agreement with diffusive shock acceleration models in the prediction of power spectra for accelerated particles in the upstream region. However, they also reveal the presence of spectral break in the high-energy part of the spectra. The role of the second-order Fermi-like acceleration at the initial stage of the acceleration is discussed. The test case used in the paper is based on ISEE-3 data collected for the shock of 1978 November 12.

  3. PROTON ACCELERATION AT OBLIQUE SHOCKS

    SciTech Connect

    Galinsky, V. L.; Shevchenko, V. I.

    2011-06-20

    Acceleration at the shock waves propagating oblique to the magnetic field is studied using a recently developed theoretical/numerical model. The model assumes that resonant hydromagnetic wave-particle interaction is the most important physical mechanism relevant to motion and acceleration of particles as well as to excitation and damping of waves. The treatment of plasma and waves is self-consistent and time dependent. The model uses conservation laws and resonance conditions to find where waves will be generated or damped, and hence particles will be pitch-angle-scattered. The total distribution is included in the model and neither introduction of separate population of seed particles nor some ad hoc escape rate of accelerated particles is needed. Results of the study show agreement with diffusive shock acceleration models in the prediction of power spectra for accelerated particles in the upstream region. However, they also reveal the presence of spectral break in the high-energy part of the spectra. The role of the second-order Fermi-like acceleration at the initial stage of the acceleration is discussed. The test case used in the paper is based on ISEE-3 data collected for the shock of 1978 November 12.

  4. Berkeley Proton Linear Accelerator

    DOE R&D Accomplishments Database

    Alvarez, L. W.; Bradner, H.; Franck, J.; Gordon, H.; Gow, J. D.; Marshall, L. C.; Oppenheimer, F. F.; Panofsky, W. K. H.; Richman, C.; Woodyard, J. R.

    1953-10-13

    A linear accelerator, which increases the energy of protons from a 4 Mev Van de Graaff injector, to a final energy of 31.5 Mev, has been constructed. The accelerator consists of a cavity 40 feet long and 39 inches in diameter, excited at resonance in a longitudinal electric mode with a radio-frequency power of about 2.2 x 10{sup 6} watts peak at 202.5 mc. Acceleration is made possible by the introduction of 46 axial "drift tubes" into the cavity, which is designed such that the particles traverse the distance between the centers of successive tubes in one cycle of the r.f. power. The protons are longitudinally stable as in the synchrotron, and are stabilized transversely by the action of converging fields produced by focusing grids. The electrical cavity is constructed like an inverted airplane fuselage and is supported in a vacuum tank. Power is supplied by 9 high powered oscillators fed from a pulse generator of the artificial transmission line type.

  5. TRACKING ACCELERATOR SETTINGS.

    SciTech Connect

    D OTTAVIO,T.; FU, W.; OTTAVIO, D.P.

    2007-10-15

    Recording setting changes within an accelerator facility provides information that can be used to answer questions about when, why, and how changes were made to some accelerator system. This can be very useful during normal operations, but can also aid with security concerns and in detecting unusual software behavior. The Set History System (SHS) is a new client-server system developed at the Collider-Accelerator Department of Brookhaven National Laboratory to provide these capabilities. The SHS has been operational for over two years and currently stores about IOOK settings per day into a commercial database management system. The SHS system consists of a server written in Java, client tools written in both Java and C++, and a web interface for querying the database of setting changes. The design of the SHS focuses on performance, portability, and a minimal impact on database resources. In this paper, we present an overview of the system design along with benchmark results showing the performance and reliability of the SHS over the last year.

  6. Accelerators for Intensity Frontier Research

    SciTech Connect

    Derwent, Paul; /Fermilab

    2012-05-11

    In 2008, the Particle Physics Project Prioritization Panel identified three frontiers for research in high energy physics, the Energy Frontier, the Intensity Frontier, and the Cosmic Frontier. In this paper, I will describe how Fermilab is configuring and upgrading the accelerator complex, prior to the development of Project X, in support of the Intensity Frontier.

  7. Progress on plasma accelerators

    SciTech Connect

    Chen, P.

    1986-05-01

    Several plasma accelerator concepts are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA) and the Plasma Wake Field Accelerator (PWFA). Various accelerator physics issues regarding these schemes are discussed, and numerical examples on laboratory scale experiments are given. The efficiency of plasma accelerators is then revealed with suggestions on improvements. Sources that cause emittance growth are discussed briefly.

  8. Epipolar Consistency in Transmission Imaging.

    PubMed

    Aichert, André; Berger, Martin; Wang, Jian; Maass, Nicole; Doerfler, Arnd; Hornegger, Joachim; Maier, Andreas K

    2015-11-01

    This paper presents the derivation of the Epipolar Consistency Conditions (ECC) between two X-ray images from the Beer-Lambert law of X-ray attenuation and the Epipolar Geometry of two pinhole cameras, using Grangeat's theorem. We motivate the use of Oriented Projective Geometry to express redundant line integrals in projection images and define a consistency metric, which can be used, for instance, to estimate patient motion directly from a set of X-ray images. We describe in detail the mathematical tools to implement an algorithm to compute the Epipolar Consistency Metric and investigate its properties with detailed random studies on both artificial and real FD-CT data. A set of six reference projections of the CT scan of a fish were used to evaluate accuracy and precision of compensating for random disturbances of the ground truth projection matrix using an optimization of the consistency metric. In addition, we use three X-ray images of a pumpkin to prove applicability to real data. We conclude, that the metric might have potential in applications related to the estimation of projection geometry. By expression of redundancy between two arbitrary projection views, we in fact support any device or acquisition trajectory which uses a cone-beam geometry. We discuss certain geometric situations, where the ECC provide the ability to correct 3D motion, without the need for 3D reconstruction. PMID:25915956

  9. Averaging Internal Consistency Reliability Coefficients

    ERIC Educational Resources Information Center

    Feldt, Leonard S.; Charter, Richard A.

    2006-01-01

    Seven approaches to averaging reliability coefficients are presented. Each approach starts with a unique definition of the concept of "average," and no approach is more correct than the others. Six of the approaches are applicable to internal consistency coefficients. The seventh approach is specific to alternate-forms coefficients. Although the…

  10. Attitude Consistency Among American Youth.

    ERIC Educational Resources Information Center

    Mott, Frank L.; Mott, Susan H.

    Attitudes of youth (ages 14-21) toward fertility expectations and women's roles are examined for consistency (e.g., whether high career expectations are correlated with a desire for fewer children). Approximately 12,000 White, Black, and Hispanic youth rated their attitudes toward statements that a woman's place is in the home, employment of wives…

  11. Measurement of Coriolis Acceleration with a Smartphone

    ERIC Educational Resources Information Center

    Shaku, Asif; Kraft, Jakob

    2016-01-01

    Undergraduate physics laboratories seldom have experiments that measure the Coriolis acceleration. This has traditionally been the case owing to the inherent complexities of making such measurements. Articles on the experimental determination of the Coriolis acceleration are few and far between in the physics literature. However, because modern…

  12. Space Experiments with Particle Accelerators (SEPAC)

    NASA Technical Reports Server (NTRS)

    Roberts, W. T.

    1985-01-01

    The space experiments with particle accelerators (SEPAC) instruments consist of an electron accelerator, a plasma accelerator, a neutral gas (N2) release device, particle and field diagnostic instruments, and a low light level television system. These instruments are used to accomplish multiple experiments: to study beam particle interactions and other plasma processes; as probes to investigate magnetospheric processes; and as perturbation devices to study energy coupling mechanisms in the magnetosphere, ionosphere, and upper atmosphere.

  13. Consistent interpretations of quantum mechanics

    NASA Astrophysics Data System (ADS)

    Omnès, Roland

    1992-04-01

    Within the last decade, significant progress has been made towards a consistent and complete reformulation of the Copenhagen interpretation (an interpretation consisting in a formulation of the experimental aspects of physics in terms of the basic formalism; it is consistent if free from internal contradiction and complete if it provides precise predictions for all experiments). The main steps involved decoherence (the transition from linear superpositions of macroscopic states to a mixing), Griffiths histories describing the evolution of quantum properties, a convenient logical structure for dealing with histories, and also some progress in semiclassical physics, which was made possible by new methods. The main outcome is a theory of phenomena, viz., the classically meaningful properties of a macroscopic system. It shows in particular how and when determinism is valid. This theory can be used to give a deductive form to measurement theory, which now covers some cases that were initially devised as counterexamples against the Copenhagen interpretation. These theories are described, together with their applications to some key experiments and some of their consequences concerning epistemology.

  14. Beam loss caused by edge focusing of injection bump magnets and its mitigation in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

    NASA Astrophysics Data System (ADS)

    Hotchi, H.; Tani, N.; Watanabe, Y.; Harada, H.; Kato, S.; Okabe, K.; Saha, P. K.; Tamura, F.; Yoshimoto, M.

    2016-01-01

    In the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex, transverse injection painting is utilized not only to suppress space-charge induced beam loss in the low energy region but also to mitigate foil scattering beam loss during charge-exchange injection. The space-charge induced beam loss is well minimized by the combination of modest transverse painting and full longitudinal painting. But, for sufficiently mitigating the foil scattering part of beam loss, the transverse painting area has to be further expanded. However, such a wide-ranging transverse painting had not been realized until recently due to beta function beating caused by edge focusing of pulsed injection bump magnets during injection. This beta function beating additionally excites random betatron resonances through a distortion of the lattice superperiodicity, and its resultant deterioration of the betatron motion stability causes significant extra beam loss when expanding the transverse painting area. To solve this issue, we newly installed pulse-type quadrupole correctors to compensate the beta function beating. This paper presents recent experimental results on this correction scheme for suppressing the extra beam loss, while discussing the beam loss and its mitigation mechanisms with the corresponding numerical simulations.

  15. Three Stages of the NICA Accelerator Complex

    NASA Astrophysics Data System (ADS)

    Kekelidze, V. D.; Lednicky, R.; Matveev, V. A.; Meshkov, I. N.; Sorin, A. S.; Trubnikov, G. V.

    2016-01-01

    The Nuclotron-based Ion Collider fAcility (NICA) project is under development at JINR (Dubna). The general goals of the project are to provide colliding beams for experimental studies of both hot and dense strongly interacting baryonic matter and spin physics (in collisions of polarized protons and deuterons). The first program will require the running of heavy ion mode in the energy range of √sNN = 4÷11 GeV at an average luminosity of L = 1•1027 cm-2-s-1 for 197Au79 nuclei. This stage of the project will be preceded by fixed target experiments with the heavy ion beam to be extracted from the Nuclotron at kinetic energies up to 4.5 GeV/u. The polarized beam mode is proposed to be used in the energy range of √sNN = 12÷27 GeV (protons) at luminosities up to 1 • 1032 cm-2-s-1. This report contains a brief description of the facility scheme and characteristics in the heavy ion operation mode, the description of the MultiPurpose Detector (MPD), and characteristics of the reactions of the colliding ions, which will allow us to detect the mixed phase formation. The plans and status of the project development are presented.

  16. Three stages of the NICA accelerator complex

    NASA Astrophysics Data System (ADS)

    Kekelidze, V. D.; Lednicky, R.; Matveev, V. A.; Meshkov, I. N.; Sorin, A. S.; Trubnikov, G. V.

    2016-08-01

    The Nuclotron-based Ion Collider fAcility (NICA) project is under development at JINR (Dubna). The general goals of the project are to provide colliding beams for experimental studies of both hot and dense strongly interacting baryonic matter and spin physics (in collisions of polarized protons and deuterons). The first program will require the running of heavy-ion mode in the energy range of √{s_{NN}} = 4-11 GeV at luminosities up to L = 1\\cdot 10^{27} cm-2 s-1 for 197Au79 nuclei (see details in sect. 4). This stage of the project will be preceded by fixed target experiments with the heavy-ion beam to be extracted from the Nuclotron at kinetic energies up to 4.5 GeV/u. The polarized beam mode is proposed to be used in the energy range of √{s_{NN}} = 12-27 GeV (protons) at luminosities up to 1\\cdot 10^{32} cm-2 s-1. This report contains a brief description of the facility scheme and characteristics in the heavy-ion operation mode, the description of the MultiPurpose Detector (MPD), and characteristics of the reactions of the colliding ions, which will allow us to detect the mixed phase formation. The plans and status of the project development are presented.

  17. Human Pose Estimation Using Consistent Max Covering.

    PubMed

    Jiang, Hao

    2011-09-01

    A novel consistent max-covering method is proposed for human pose estimation. We focus on problems in which a rough foreground estimation is available. Pose estimation is formulated as a jigsaw puzzle problem in which the body part tiles maximally cover the foreground region, match local image features, and satisfy body plan and color constraints. This method explicitly imposes a global shape constraint on the body part assembly. It anchors multiple body parts simultaneously and introduces hyperedges in the part relation graph, which is essential for detecting complex poses. Using multiple cues in pose estimation, our method is resistant to cluttered foregrounds. We propose an efficient linear method to solve the consistent max-covering problem. A two-stage relaxation finds the solution in polynomial time. Our experiments on a variety of images and videos show that the proposed method is more robust than previous locally constrained methods. PMID:21576747

  18. Conceptual design of industrial free electron laser using superconducting accelerator

    SciTech Connect

    Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N.

    1995-12-31

    Paper presents conceptual design of free electron laser (FEL) complex for industrial applications. The FEL complex consists of three. FEL oscillators with the optical output spanning the infrared (IR) and ultraviolet (UV) wave-lengths ({lambda} = 0.3...20 {mu}m) and with the average output power 10 - 20 kW. The driving beam for the FELs is produced by a superconducting accelerator. The electron beam is transported to the FELs via three beam lines (125 MeV and 2 x 250 MeV). Peculiar feature of the proposed complex is a high efficiency of the. FEL oscillators, up to 20 %. This becomes possible due to the use of quasi-continuous electron beam and the use of the time-dependent undulator tapering.

  19. An MCNPX accelerator beam source

    SciTech Connect

    Durkee, Joe W.; Elson, Jay S.; Jason, Andrew; Johns, Russell C.; Waters, Laurie S.

    2009-06-04

    MCNPX is a powerful Monte Carlo code that can be used to conduct sophisticated radiation-transport simulations involving complex physics and geometry. Although MCNPX possesses a wide assortment of standardized modeling tools, there are instances in which a user's needs can eclipse existing code capabilities. Fortunately, although it may not be widely known, MCNPX can accommodate many customization needs. In this article, we demonstrate source-customization capability for a new SOURCE subroutine as part of our development to enable simulations involving accelerator beams for active-interrogation studies. Simulation results for a muon beam are presented to illustrate the new accelerator-source capability.

  20. Consistent integration of geo-information

    NASA Astrophysics Data System (ADS)

    Hansen, T. M.; Cordua, K. S.

    2014-12-01

    Probabilistically formulated inverse problems can be seen as an application of data integration. Two types of information are (almost) always available: 1) geophysical data, and 2) information about geology and geologically plausible structures. The inverse problem consists of integrating the information available from geophysical data and geological information. In recent years inversion algorithms have emerged that allow integration of such different information. However such methods only provides useful results if the geological and geophysical information provided are consistent. Using weakly informed prior models and/or sparse uncertain geophysical data typically no problems with consistency arise. However, as data coverage and quality increase and still more complex and detailed prior information can be quantified (using e.g multiple point based statistics) then the risk of problems with consistency increases. Inconsistency between two independent sources of information about the same subsurface model, means that either one or both sources of information must be wrong.We will demonstrate that using cross hole GPR tomographic data, that such consistency problems exist, and that they can dramatically affect inversion results. The problem is two folded: 1) One will typically underestimate the error associated with geophysical data, and 2) Multiple-point based prior models often provide such detailed a priori information that it will not be possible to find a priori acceptable models that lead to a data fit within measurement uncertainties. We demonstrate that if inversion is forced on inconsistent information, then the solution to the inverse problem may be earth models that neither fit the data within their uncertainty, nor represent realistic geologically features. In the worst case such models will show artefacts that appear well resolved, and that can have severe effect on subsequent flow modeling. We will demonstrate how such inconsistencies can be

  1. On the consistency of MPS

    NASA Astrophysics Data System (ADS)

    Souto-Iglesias, Antonio; Macià, Fabricio; González, Leo M.; Cercos-Pita, Jose L.

    2013-03-01

    The consistency of the Moving Particle Semi-implicit (MPS) method in reproducing the gradient, divergence and Laplacian differential operators is discussed in the present paper. Its relation to the Smoothed Particle Hydrodynamics (SPH) method is rigorously established. The application of the MPS method to solve the Navier-Stokes equations using a fractional step approach is treated, unveiling inconsistency problems when solving the Poisson equation for the pressure. A new corrected MPS method incorporating boundary terms is proposed. Applications to one dimensional boundary value Dirichlet and mixed Neumann-Dirichlet problems and to two-dimensional free-surface flows are presented.

  2. KEKB accelerator control system

    NASA Astrophysics Data System (ADS)

    Akasaka, Nobumasa; Akiyama, Atsuyoshi; Araki, Sakae; Furukawa, Kazuro; Katoh, Tadahiko; Kawamoto, Takashi; Komada, Ichitaka; Kudo, Kikuo; Naito, Takashi; Nakamura, Tatsuro; Odagiri, Jun-ichi; Ohnishi, Yukiyoshi; Sato, Masayuki; Suetake, Masaaki; Takeda, Shigeru; Takeuchi, Yasunori; Yamamoto, Noboru; Yoshioka, Masakazu; Kikutani, Eji

    2003-02-01

    The KEKB accelerator control system including a control computer system, a timing distribution system, and a safety control system are described. KEKB accelerators were installed in the same tunnel where the TRISTAN accelerator was. There were some constraints due to the reused equipment. The control system is based on Experimental Physics and Industrial Control System (EPICS). In order to reduce the cost and labor for constructing the KEKB control system, as many CAMAC modules as possible are used again. The guiding principles of the KEKB control computer system are as follows: use EPICS as the controls environment, provide a two-language system for developing application programs, use VMEbus as frontend computers as a consequence of EPICS, use standard buses, such as CAMAC, GPIB, VXIbus, ARCNET, RS-232 as field buses and use ergonomic equipment for operators and scientists. On the software side, interpretive Python and SAD languages are used for coding application programs. The purpose of the radiation safety system is to protect personnel from radiation hazards. It consists of an access control system and a beam interlock system. The access control system protects people from strong radiation inside the accelerator tunnel due to an intense beam, by controlling access to the beamline area. On the other hand, the beam interlock system prevents people from radiation exposure by interlocking the beam operation. For the convenience of accelerator operation and access control, the region covered by the safety system is divided into three major access control areas: the KEKB area, the PF-AR area, and the beam-transport (BT) area. The KEKB control system required a new timing system to match a low longitudinal acceptance due to a low-alpha machine. This timing system is based on a frequency divider/multiply technique and a digital delay technique. The RF frequency of the KEKB rings and that of the injector Linac are locked with a common divisor frequency. The common

  3. Tomography of injection and acceleration of monoenergetic electrons in a laser-wakefield accelerator.

    PubMed

    Hsieh, C-T; Huang, C-M; Chang, C-L; Ho, Y-C; Chen, Y-S; Lin, J-Y; Wang, J; Chen, S-Y

    2006-03-10

    A tomographic diagnosis method was developed to systematically resolve the injection and acceleration processes of a monoenergetic electron beam in a laser-wakefield accelerator. It was found that all the monoenergetic electrons are injected at the same location in the plasma column and accelerated from 5 to 55 MeV energy in 200 microm distance. This is a direct measurement of the real acceleration gradient in a laser-wakefield accelerator, and the experimental data are consistent with the model of transverse wave breaking and beam loading for monoenergetic electron injection. PMID:16606269

  4. Community Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

    SciTech Connect

    Spentzouris, P.; Cary, J.; McInnes, L.C.; Mori, W.; Ng, C.; Ng, E.; Ryne, R.; /LBL, Berkeley

    2011-11-14

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors. ComPASS is in the first year of executing its plan to develop the next-generation HPC accelerator modeling tools. ComPASS aims to develop an integrated simulation environment that will utilize existing and new accelerator physics modules with petascale capabilities, by employing modern computing and solver technologies. The ComPASS vision is to deliver to accelerator scientists a virtual accelerator and virtual prototyping modeling environment, with the necessary multiphysics, multiscale capabilities. The plan for this development includes delivering accelerator modeling applications appropriate for each stage of the ComPASS software evolution. Such applications are already being used to address challenging problems in accelerator design and optimization. The ComPASS organization

  5. APT accelerator. Topical report

    SciTech Connect

    Lawrence, G.; Rusthoi, D.

    1995-03-01

    The Accelerator Production of Tritium (APT) project, sponsored by Department of Energy Defense Programs (DOE/DP), involves the preconceptual design of an accelerator system to produce tritium for the nation`s stockpile of nuclear weapons. Tritium is an isotope of hydrogen used in nuclear weapons, and must be replenished because of radioactive decay (its half-life is approximately 12 years). Because the annual production requirements for tritium has greatly decreased since the end of the Cold War, an alternative approach to reactors for tritium production, based on a linear accelerator, is now being seriously considered. The annual tritium requirement at the time this study was undertaken (1992-1993) was 3/8 that of the 1988 goal, usually stated as 3/8-Goal. Continued reduction in the number of weapons in the stockpile has led to a revised (lower) production requirement today (March, 1995). The production requirement needed to maintain the reduced stockpile, as stated in the recent Nuclear Posture Review (summer 1994) is approximately 3/16-Goal, half the previous level. The Nuclear Posture Review also requires that the production plant be designed to accomodate a production increase (surge) to 3/8-Goal capability within five years, to allow recovery from a possible extended outage of the tritium plant. A multi-laboratory team, collaborating with several industrial partners, has developed a preconceptual APT design for the 3/8-Goal, operating at 75% capacity. The team has presented APT as a promising alternative to the reactor concepts proposed for Complex-21. Given the requirements of a reduced weapons stockpile, APT offers both significant safety, environmental, and production-fexibility advantages in comparison with reactor systems, and the prospect of successful development in time to meet the US defense requirements of the 21st Century.

  6. Reliable timing systems for computer controlled accelerators

    NASA Astrophysics Data System (ADS)

    Knott, Jürgen; Nettleton, Robert

    1986-06-01

    Over the past decade the use of computers has set new standards for control systems of accelerators with ever increasing complexity coupled with stringent reliability criteria. In fact, with very slow cycling machines or storage rings any erratic operation or timing pulse will cause the loss of precious particles and waste hours of time and effort of preparation. Thus, for the CERN linac and LEAR (Low Energy Antiproton Ring) timing system reliability becomes a crucial factor in the sense that all components must operate practically without fault for very long periods compared to the effective machine cycle. This has been achieved by careful selection of components and design well below thermal and electrical limits, using error detection and correction where possible, as well as developing "safe" decoding techniques for serial data trains. Further, consistent structuring had to be applied in order to obtain simple and flexible modular configurations with very few components on critical paths and to minimize the exchange of information to synchronize accelerators. In addition, this structuring allows the development of efficient strategies for on-line and off-line fault diagnostics. As a result, the timing system for Linac 2 has, so far, been operating without fault for three years, the one for LEAR more than one year since its final debugging.

  7. Maintaining consistency in distributed systems

    NASA Technical Reports Server (NTRS)

    Birman, Kenneth P.

    1991-01-01

    In systems designed as assemblies of independently developed components, concurrent access to data or data structures normally arises within individual programs, and is controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operation are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems - often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability.

  8. Thermodynamically consistent continuum dislocation dynamics

    NASA Astrophysics Data System (ADS)

    Hochrainer, Thomas

    2016-03-01

    Dislocation based modeling of plasticity is one of the central challenges at the crossover of materials science and continuum mechanics. Developing a continuum theory of dislocations requires the solution of two long standing problems: (i) to represent dislocation kinematics in terms of a reasonable number of variables and (ii) to derive averaged descriptions of the dislocation dynamics (i.e. material laws) in terms of these variables. The kinematic problem (i) was recently solved through the introduction of continuum dislocation dynamics (CDD), which provides kinematically consistent evolution equations of dislocation alignment tensors, presuming a given average dislocation velocity (Hochrainer, T., 2015, Multipole expansion of continuum dislocations dynamics in terms of alignment tensors. Philos. Mag. 95 (12), 1321-1367). In the current paper we demonstrate how a free energy formulation may be used to solve the dynamic closure problem (ii) in CDD. We do so exemplarily for the lowest order CDD variant for curved dislocations in a single slip situation. In this case, a thermodynamically consistent average dislocation velocity is found to comprise five mesoscopic shear stress contributions. For a postulated free energy expression we identify among these stress contributions a back-stress term and a line-tension term, both of which have already been postulated for CDD. A new stress contribution occurs which is missing in earlier CDD models including the statistical continuum theory of straight parallel edge dislocations (Groma, I., Csikor, F.F., Zaiser, M., 2003. Spatial correlations and higher-order gradient terms in a continuum description of dislocation dynamics. Acta Mater. 51, 1271-1281). Furthermore, two entirely new stress contributions arise from the curvature of dislocations.

  9. Accelerated life testing effects on CMOS microcircuit characteristics

    NASA Technical Reports Server (NTRS)

    1980-01-01

    This report covers the time period from May 1976 to December 1979 and encompasses the three phases of accelerated testing: Phase 1, the 250 C testing; Phase 2, the 200 C testing; and Phase 3, the 125 C testing. The duration of the test in Phase 1 and Phase 2 was sufficient to take the devices into the wear out region. The wear out distributions were used to estimate the activation energy between the 250 C and the 200 C test temperatures. The duration of the 125 C test, 20,000 hours, was not sufficient to bring the test devices into the wear out region; consequently the third data point at 125 C for determining the consistency of activation energy could not be obtained. It was estimated that, for the most complex of the three device types, the activation energy between 200 C and 125 C should be at least as high as that between 250 C and 200 C. The practicality of the use of high temperature for the accelerated life tests from the point of view of durability of equipment was assessed. Guidelines for the development of accelerated life test conditions were proposed. The use of the silicon nitride overcoat to improve the high temperature accelerated life test characteristics of CMOS microcircuits was explored in Phase 4 of this study and is attached as an appendix to this report.

  10. Radiation from Accelerated Particles in Shocks and Reconnections

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Zhang, B.; Niemiec, J.; Medvedev, M.; Hardee, P.; Mizuno, Y.; Nordlund, A.; Frederiksen, J. T.; Sol, H.; Pohl, M.; Hartmann, D. H.; Fishman, G. J.

    2011-01-01

    Plasma instabilities are responsible not only for the onset and mediation of collisionless shocks but also for the associated acceleration of particles. We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. These magnetic fields contribute to the electrons transverse deflection and, more generally, relativistic acceleration behind the shock. We have calculated, self-consistently, the radiation from electrons accelerated in the turbulent magnetic fields. We found that the synthetic spectra depend on the Lorentz factor of the jet, its thermal temperature and strength of the generated magnetic fields. We are currently investigating the specific case of a jet colliding with an anti-parallel magnetized ambient medium. The properties of the radiation may be important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets in general, and supernova remnants.

  11. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2006-04-18

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  12. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2005-06-14

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  13. Accelerator science in medical physics.

    PubMed

    Peach, K; Wilson, P; Jones, B

    2011-12-01

    The use of cyclotrons and synchrotrons to accelerate charged particles in hospital settings for the purpose of cancer therapy is increasing. Consequently, there is a growing demand from medical physicists, radiographers, physicians and oncologists for articles that explain the basic physical concepts of these technologies. There are unique advantages and disadvantages to all methods of acceleration. Several promising alternative methods of accelerating particles also have to be considered since they will become increasingly available with time; however, there are still many technical problems with these that require solving. This article serves as an introduction to this complex area of physics, and will be of benefit to those engaged in cancer therapy, or who intend to acquire such technologies in the future. PMID:22374548

  14. Accelerator science in medical physics

    PubMed Central

    Peach, K; Wilson, P; Jones, B

    2011-01-01

    The use of cyclotrons and synchrotrons to accelerate charged particles in hospital settings for the purpose of cancer therapy is increasing. Consequently, there is a growing demand from medical physicists, radiographers, physicians and oncologists for articles that explain the basic physical concepts of these technologies. There are unique advantages and disadvantages to all methods of acceleration. Several promising alternative methods of accelerating particles also have to be considered since they will become increasingly available with time; however, there are still many technical problems with these that require solving. This article serves as an introduction to this complex area of physics, and will be of benefit to those engaged in cancer therapy, or who intend to acquire such technologies in the future. PMID:22374548

  15. Accelerations in Flight

    NASA Technical Reports Server (NTRS)

    Norton, F H; Allen, E T

    1921-01-01

    This report deals with the accelerations obtained in flight on various airplanes at Langley Field for the purpose of obtaining the magnitude of the load factors in flight and to procure information on the behavior of an airplane in various maneuvers. The instrument used in these tests was a recording accelerometer of a new type designed by the technical staff of the National Advisory Committee for Aeronautics. The instrument consists of a flat steel spring supported rigidly at one end so that the free end may be deflected by its own weight from its neutral position by any acceleration acting at right angles to the plane of the spring. This deflection is measured by a very light tilting mirror caused to rotate by the deflection of the spring, which reflected the beam of light onto a moving film. The motion of the spring is damped by a thin aluminum vane which rotates with the spring between the poles of an electric magnet. Records were taken on landings and takeoffs, in loops, spins, spirals, and rolls.

  16. Optical Bragg accelerators.

    PubMed

    Mizrahi, Amit; Schächter, Levi

    2004-01-01

    It is demonstrated that a Bragg waveguide consisting of a series of dielectric layers may form an excellent optical acceleration structure. Confinement of the accelerating fields is achieved, for both planar and cylindrical configurations by adjusting the first dielectric layer width. A typical structure made of silica and zirconia may support gradients of the order of 1 GV/m with an interaction impedance of a few hundreds of ohms and with an energy velocity of less than 0.5c. An interaction impedance of about 1000 Omega may be obtained by replacing the Zirconia with a (fictitious) material of epsilon=25. Special attention is paid to the wake field developing in such a structure. In the case of a relatively small number of layers, it is shown that the total electromagnetic power emitted is proportional to the square of the number of electrons in the macrobunch and inversely proportional to the number of microbunches; this power is also inversely proportional to the square of the internal radius of the structure for a cylindrical structure, and to the width of the vacuum core in a planar structure. Quantitative results are given for a higher number of dielectric layers, showing that in comparison to a structure bounded by metallic walls, the emitted power is significantly smaller due to propagation bands allowing electromagnetic energy to escape. PMID:15324182

  17. Broadband accelerator control network

    SciTech Connect

    Skelly, J.; Clifford, T.; Frankel, R.

    1983-01-01

    A broadband data communications network has been implemented at BNL for control of the Alternating Gradient Synchrotron (AG) proton accelerator, using commercial CATV hardware, dual coaxial cables as the communications medium, and spanning 2.0 km. A 4 MHz bandwidth Digital Control channel using CSMA-CA protocol is provided for digital data transmission, with 8 access nodes available over the length of the RELWAY. Each node consists of an rf modem and a microprocessor-based store-and-forward message handler which interfaces the RELWAY to a branch line implemented in GPIB. A gateway to the RELWAY control channel for the (preexisting) AGS Computerized Accelerator Operating system has been constructed using an LSI-11/23 microprocessor as a device in a GPIB branch line. A multilayer communications protocol has been defined for the Digital Control Channel, based on the ISO Open Systems Interconnect layered model, and a RELWAY Device Language defined as the required universal language for device control on this channel.

  18. The Consistent Vehicle Routing Problem

    SciTech Connect

    Groer, Christopher S; Golden, Bruce; Edward, Wasil

    2009-01-01

    In the small package shipping industry (as in other industries), companies try to differentiate themselves by providing high levels of customer service. This can be accomplished in several ways, including online tracking of packages, ensuring on-time delivery, and offering residential pickups. Some companies want their drivers to develop relationships with customers on a route and have the same drivers visit the same customers at roughly the same time on each day that the customers need service. These service requirements, together with traditional constraints on vehicle capacity and route length, define a variant of the classical capacitated vehicle routing problem, which we call the consistent VRP (ConVRP). In this paper, we formulate the problem as a mixed-integer program and develop an algorithm to solve the ConVRP that is based on the record-to-record travel algorithm. We compare the performance of our algorithm to the optimal mixed-integer program solutions for a set of small problems and then apply our algorithm to five simulated data sets with 1,000 customers and a real-world data set with more than 3,700 customers. We provide a technique for generating ConVRP benchmark problems from vehicle routing problem instances given in the literature and provide our solutions to these instances. The solutions produced by our algorithm on all problems do a very good job of meeting customer service objectives with routes that have a low total travel time.

  19. Operational experience on the Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.; Babzien, M.; Ben-Zvi, I.

    1994-09-01

    Brookhaven National Laboratory Accelerator Test Facility is a laser-electron linear accelerator complex designed to provide high brightness beams for testing of advanced acceleration concepts and high power pulsed photon sources. Results of electron beam parameters attained during the commissioning of the nominally 45 MeV energy machine are presented.

  20. Pulsed Plasma Accelerator Modeling

    NASA Technical Reports Server (NTRS)

    Goodman, M.; Kazeminezhad, F.; Owens, T.

    2009-01-01

    This report presents the main results of the modeling task of the PPA project. The objective of this task is to make major progress towards developing a new computational tool with new capabilities for simulating cylindrically symmetric 2.5 dimensional (2.5 D) PPA's. This tool may be used for designing, optimizing, and understanding the operation of PPA s and other pulsed power devices. The foundation for this task is the 2-D, cylindrically symmetric, magnetohydrodynamic (MHD) code PCAPPS (Princeton Code for Advanced Plasma Propulsion Simulation). PCAPPS was originally developed by Sankaran (2001, 2005) to model Lithium Lorentz Force Accelerators (LLFA's), which are electrode based devices, and are typically operated in continuous magnetic field to the model, and implementing a first principles, self-consistent algorithm to couple the plasma and power circuit that drives the plasma dynamics.

  1. Dusty-Plasma Particle Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2005-01-01

    A dusty-plasma apparatus is being investigated as means of accelerating nanometer- and micrometer-sized particles. Applications for the dusty-plasma particle accelerators fall into two classes: Simulation of a variety of rapidly moving dust particles and micrometeoroids in outer-space environments that include micrometeoroid streams, comet tails, planetary rings, and nebulae and Deposition or implantation of nanoparticles on substrates for diverse industrial purposes that could include hardening, increasing thermal insulation, altering optical properties, and/or increasing permittivities of substrate materials. Relative to prior apparatuses used for similar applications, dusty-plasma particle accelerators offer such potential advantages as smaller size, lower cost, less complexity, and increased particle flux densities. A dusty-plasma particle accelerator exploits the fact that an isolated particle immersed in plasma acquires a net electric charge that depends on the relative mobilities of electrons and ions. Typically, a particle that is immersed in a low-temperature, partially ionized gas, wherein the average kinetic energy of electrons exceeds that of ions, causes the particle to become negatively charged. The particle can then be accelerated by applying an appropriate electric field. A dusty-plasma particle accelerator (see figure) includes a plasma source such as a radio-frequency induction discharge apparatus containing (1) a shallow cup with a biasable electrode to hold the particles to be accelerated and (2) a holder for the substrate on which the particles are to impinge. Depending on the specific design, a pair of electrostatic-acceleration grids between the substrate and discharge plasma can be used to both collimate and further accelerate particles exiting the particle holder. Once exposed to the discharge plasma, the particles in the cup quickly acquire a negative charge. Application of a negative voltage pulse to the biasable electrode results in the

  2. Electroerosive wear of the barrel of a coaxial hybrid magnetoplasma accelerator in the acceleration of solids

    NASA Astrophysics Data System (ADS)

    Gerasimov, D. Yu.; Sivkov, A. A.

    2012-01-01

    The main regularities of electroerosive wear of the barrel of a hybrid coaxial magnetoplasma accelerator in the acceleration of solids are studied. In order to significantly reduce the erosive wear of the barrel without changing the dynamics of solid projectiles, a system of discharge shunting in the acceleration channel was used. It is shown that the plasma structure of a high-current arc discharge is fountain-shaped and its bridge consists of numerous discrete conduction channels.

  3. Commnity Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

    SciTech Connect

    Spentzouris, Panagiotis; Cary, John; Mcinnes, Lois Curfman; Mori, Warren; Ng, Cho; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

    2008-07-01

    The design and performance optimization of particle accelerators is essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC1 Accelerator Science and Technology project, the SciDAC2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modeling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multi-physics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.

  4. Community petascale project for accelerator science and simulation : Advancing computational science for future accelerators and accelerator technologies.

    SciTech Connect

    Spentzouris, P.; Cary, J.; McInnes, L. C.; Mori, W.; Ng, C.; Ng, E.; Ryne, R.

    2008-01-01

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R & D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.

  5. Commnity Petascale Project for Accelerator Science And Simulation: Advancing Computational Science for Future Accelerators And Accelerator Technologies

    SciTech Connect

    Spentzouris, Panagiotis; Cary, John; Mcinnes, Lois Curfman; Mori, Warren; Ng, Cho; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

    2011-10-21

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.

  6. TURBULENT SHEAR ACCELERATION

    SciTech Connect

    Ohira, Yutaka

    2013-04-10

    We consider particle acceleration by large-scale incompressible turbulence with a length scale larger than the particle mean free path. We derive an ensemble-averaged transport equation of energetic charged particles from an extended transport equation that contains the shear acceleration. The ensemble-averaged transport equation describes particle acceleration by incompressible turbulence (turbulent shear acceleration). We find that for Kolmogorov turbulence, the turbulent shear acceleration becomes important on small scales. Moreover, using Monte Carlo simulations, we confirm that the ensemble-averaged transport equation describes the turbulent shear acceleration.

  7. Generalized arc consistency for global cardinality constraint

    SciTech Connect

    Regin, J.C.

    1996-12-31

    A global cardinality constraint (gcc) is specified in terms of a set of variables X = (x{sub 1},..., x{sub p}) which take their values in a subset of V = (v{sub 1},...,v{sub d}). It constrains the number of times a value v{sub i} {epsilon} V is assigned to a variable in X to be in an interval [l{sub i}, c{sub i}]. Cardinality constraints have proved very useful in many real-life problems, such as scheduling, timetabling, or resource allocation. A gcc is more general than a constraint of difference, which requires each interval to be. In this paper, we present an efficient way of implementing generalized arc consistency for a gcc. The algorithm we propose is based on a new theorem of flow theory. Its space complexity is O({vert_bar}X{vert_bar} {times} {vert_bar}V{vert_bar}) and its time complexity is O({vert_bar}X{vert_bar}{sup 2} {times} {vert_bar}V{vert_bar}). We also show how this algorithm can efficiently be combined with other filtering techniques.

  8. 3-D RPIC Simulations of Relativistic Jets: Particle Acceleration, Magnetic Field Generation, and Emission

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Mizuno, Y.; Hardee, P.; Hededal, C. B.; Fishman, G. J.

    2006-01-01

    Recent PIC simulations using injected relativistic electron-ion (electro-positron) jets into ambient plasmas show that acceleration occurs in relativistic shocks. The Weibel instability created in shocks is responsible for particle acceleration, and generation and amplification of highly inhomogeneous, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection in relativistic jets. The "jitter" radiation from deflected electrons has different properties than the synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understand the complex time evolution and spectral structure in relativistic jets and gamma-ray bursts. We will present recent PIC simulations which show particle acceleration and magnetic field generation. We will also calculate associated self-consistent emission from relativistic shocks.

  9. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  10. Improved plasma accelerator

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  11. Muon Collider Progress: Accelerators

    SciTech Connect

    Zisman, Michael S.

    2011-09-10

    A muon collider would be a powerful tool for exploring the energy-frontier with leptons, and would complement the studies now under way at the LHC. Such a device would offer several important benefits. Muons, like electrons, are point particles so the full center-of-mass energy is available for particle production. Moreover, on account of their higher mass, muons give rise to very little synchrotron radiation and produce very little beamstrahlung. The first feature permits the use of a circular collider that can make efficient use of the expensive rf system and whose footprint is compatible with an existing laboratory site. The second feature leads to a relatively narrow energy spread at the collision point. Designing an accelerator complex for a muon collider is a challenging task. Firstly, the muons are produced as a tertiary beam, so a high-power proton beam and a target that can withstand it are needed to provide the required luminosity of ~1 × 10{sup 34} cm{sup –2}s{sup –1}. Secondly, the beam is initially produced with a large 6D phase space, which necessitates a scheme for reducing the muon beam emittance (“cooling”). Finally, the muon has a short lifetime so all beam manipulations must be done very rapidly. The Muon Accelerator Program, led by Fermilab and including a number of U.S. national laboratories and universities, has undertaken design and R&D activities aimed toward the eventual construction of a muon collider. Design features of such a facility and the supporting R&D program are described.

  12. Acceleration gradient of a plasma wakefield accelerator

    SciTech Connect

    Uhm, Han S.

    2008-02-25

    The phase velocity of the wakefield waves is identical to the electron beam velocity. A theoretical analysis indicates that the acceleration gradient of the wakefield accelerator normalized by the wave breaking amplitude is K{sub 0}({xi})/K{sub 1}({xi}), where K{sub 0}({xi}) and K{sub 1}({xi}) are the modified Bessel functions of the second kind of order zero and one, respectively and {xi} is the beam parameter representing the beam intensity. It is also shown that the beam density must be considerably higher than the diffuse plasma density for the large radial velocity of plasma electrons that are required for a high acceleration gradient.

  13. Far field acceleration

    SciTech Connect

    Fernow, R.C.

    1995-07-01

    Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail.

  14. Angular Acceleration Without Torque?

    NASA Astrophysics Data System (ADS)

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.2

  15. Sustained linear acceleration

    NASA Technical Reports Server (NTRS)

    Fraser, T. M.

    1973-01-01

    The subjective effects of sustained acceleration are discussed, including positive, negative, forward, backward, and lateral acceleration effects. Physiological effects, such as retinal and visual response, unconsciousness and cerebral function, pulmonary response, and renal output, are studied. Human tolerance and performance under sustained acceleration are ascertained.

  16. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  17. Acceleration: It's Elementary

    ERIC Educational Resources Information Center

    Willis, Mariam

    2012-01-01

    Acceleration is one tool for providing high-ability students the opportunity to learn something new every day. Some people talk about acceleration as taking a student out of step. In actuality, what one is doing is putting a student in step with the right curriculum. Whole-grade acceleration, also called grade-skipping, usually happens between…

  18. Improving Interprofessional Consistency in Electronic Fetal Heart Rate Interpretation.

    PubMed

    Govindappagari, Shravya; Zaghi, Sahar; Zannat, Ferdous; Reimers, Laura; Goffman, Dena; Kassel, Irene; Bernstein, Peter S

    2016-07-01

    Objective To determine if mandatory online training in electronic fetal monitoring (EFM) improved agreement in documentation between obstetric care providers and nurses on labor and delivery. Methods Health care professionals working in obstetrics at our institution were required to complete a course on EFM interpretation. We performed a retrospective chart review of 701 charts including patients delivered before and after the introduction of the course to evaluate agreement among providers in their documentation of their interpretations of the EFM tracings. Results Agreement between provider and nurse documentation at the time of admission improved for variability and accelerations (variability: 91.1 vs. 98.3%, p < 0.001; and accelerations: 75.2 vs. 87.7%, p < 0.001). Similarly, agreement improved at the time of the last note prior to delivery for documentation of variability and accelerations (variability: 82.1 vs. 90.6%, p = 0.001; and accelerations: 56.7 vs. 68.6%, p = 0.0012). Agreement in interpretation of decelerations both at the time of admission and at the time of delivery increased (86.3 vs. 90.6%, p = 0.0787, and 56.7 vs. 61.1%, p = 0.2314, respectively) but was not significant. Conclusion An online EFM course can significantly improve consistency in multidisciplinary documentation of fetal heart rate tracing interpretation. PMID:26906180

  19. Voltage limitations of electrostatic accelerators

    SciTech Connect

    Hyder, H. R. McK.

    1999-04-26

    The history of electrostatic accelerators has been punctuated by a series of projects in which innovative designs have failed to meet the expectations of their designers. From the early, air-insulated Van de Graaffs at Round Hill to certain of the large pressurized heavy ion accelerators of the 1970s and 1980s, increases in size or changes in design and materials have not always led to the maximum voltages expected or extrapolated. Since these failures have continued beyond childhood into a mature technology, it is reasonable to assume that the causes of voltage limitation are varied and complex. They have remained poorly understood for a number of reasons: resources for an extended program of research into breakdown and failure of electrostatic generators have always been meager, especially for large machines devoted to nuclear research; the inaccessibility of pressurized generators makes instrumentation difficult and testing slow; the calculation of transient and dynamic effects is laborious and the results difficult to verify; voltage test experiments on operating accelerators are inhibited by the significant risk of damage due to energy release on breakdown: and the total voltages (though not the local fields) achieved in many electrostatic accelerators exceed those produced in any other man-made environment. In this review, the behavior of several generators of different designs is examined in order to assess the importance of the various design features and operating conditions that control the maximum voltage achievable in a working machine.

  20. Voltage limitations of electrostatic accelerators

    SciTech Connect

    Hyder, H.R. )

    1999-04-01

    The history of electrostatic accelerators has been punctuated by a series of projects in which innovative designs have failed to meet the expectations of their designers. From the early, air-insulated Van de Graaffs at Round Hill to certain of the large pressurized heavy ion accelerators of the 1970s and 1980s, increases in size or changes in design and materials have not always led to the maximum voltages expected or extrapolated. Since these failures have continued beyond childhood into a mature technology, it is reasonable to assume that the causes of voltage limitation are varied and complex. They have remained poorly understood for a number of reasons: resources for an extended program of research into breakdown and failure of electrostatic generators have always been meager, especially for large machines devoted to nuclear research; the inaccessibility of pressurized generators makes instrumentation difficult and testing slow; the calculation of transient and dynamic effects is laborious and the results difficult to verify; voltage test experiments on operating accelerators are inhibited by the significant risk of damage due to energy release on breakdown: and the total voltages (though not the local fields) achieved in many electrostatic accelerators exceed those produced in any other man-made environment. In this review, the behavior of several generators of different designs is examined in order to assess the importance of the various design features and operating conditions that control the maximum voltage achievable in a working machine. [copyright] [ital 1999 American Institute of Physics.

  1. Accelerating video carving from unallocated space

    NASA Astrophysics Data System (ADS)

    Kalva, Hari; Parikh, Anish; Srinivasan, Avinash

    2013-03-01

    Video carving has become an essential tool in digital forensics. Video carving enables recovery of deleted video files from hard disks. Processing data to extract videos is a computationally intensive task. In this paper we present two methods to accelerate video carving: a method to accelerate fragment extraction, and a method to accelerate combining of these fragments into video segments. Simulation results show that complexity of video fragment extraction can be reduced by as much as 75% with minimal impact on the videos recovered.

  2. Compact Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2004-01-01

    A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness, this accelerator could be nearly ideal for primary or station-keeping propulsion for spacecraft having masses between 1 and 20 kg. Because this accelerator is designed to generate beams of ions having energies between 50 and 200 eV, it could also be used for surface modification or activation of thin films.

  3. Pulsed Inductive Plasma Acceleration: Performance Optimization Criteria

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.

    2014-01-01

    Optimization criteria for pulsed inductive plasma acceleration are developed using an acceleration model consisting of a set of coupled circuit equations describing the time-varying current in the thruster and a one-dimensional momentum equation. The model is nondimensionalized, resulting in the identification of several scaling parameters that are varied to optimize the performance of the thruster. The analysis reveals the benefits of underdamped current waveforms and leads to a performance optimization criterion that requires the matching of the natural period of the discharge and the acceleration timescale imposed by the inertia of the working gas. In addition, the performance increases when a greater fraction of the propellant is initially located nearer to the inductive acceleration coil. While the dimensionless model uses a constant temperature formulation in calculating performance, the scaling parameters that yield the optimum performance are shown to be relatively invariant if a self-consistent description of energy in the plasma is instead used.

  4. High brightness electron accelerator

    DOEpatents

    Sheffield, Richard L.; Carlsten, Bruce E.; Young, Lloyd M.

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

  5. Fiber Accelerating Structures

    SciTech Connect

    Hammond, Andrew P.; /Reed Coll. /SLAC

    2010-08-25

    One of the options for future particle accelerators are photonic band gap (PBG) fiber accelerators. PBG fibers are specially designed optical fibers that use lasers to excite an electric field that is used to accelerate electrons. To improve PBG accelerators, the basic parameters of the fiber were tested to maximize defect size and acceleration. Using the program CUDOS, several accelerating modes were found that maximized these parameters for several wavelengths. The design of multiple defects, similar to having closely bound fibers, was studied to find possible coupling or the change of modes. The amount of coupling was found to be dependent on distance separated. For certain distances accelerating coupled modes were found and examined. In addition, several non-periodic fiber structures were examined using CUDOS. The non-periodic fibers produced several interesting results and promised more modes given time to study them in more detail.

  6. SuperB Progress Report for Accelerator

    SciTech Connect

    Biagini, M.E.; Boni, R.; Boscolo, M.; Buonomo, B.; Demma, T.; Drago, A.; Esposito, M.; Guiducci, S.; Mazzitelli, G.; Pellegrino, L.; Preger, M.A.; Raimondi, P.; Ricci, R.; Rotundo, U.; Sanelli, C.; Serio, M.; Stella, A.; Tomassini, S.; Zobov, M.; Bertsche, K.; Brachman, A.; /SLAC /Novosibirsk, IYF /INFN, Pisa /Pisa U. /Orsay, LAL /Annecy, LAPP /LPSC, Grenoble /IRFU, SPP, Saclay /DESY /Cockroft Inst. Accel. Sci. Tech. /U. Liverpool /CERN

    2012-02-14

    This report details the progress made in by the SuperB Project in the area of the Collider since the publication of the SuperB Conceptual Design Report in 2007 and the Proceedings of SuperB Workshop VI in Valencia in 2008. With this document we propose a new electron positron colliding beam accelerator to be built in Italy to study flavor physics in the B-meson system at an energy of 10 GeV in the center-of-mass. This facility is called a high luminosity B-factory with a project name 'SuperB'. This project builds on a long history of successful e+e- colliders built around the world, as illustrated in Figure 1.1. The key advances in the design of this accelerator come from recent successes at the DAFNE collider at INFN in Frascati, Italy, at PEP-II at SLAC in California, USA, and at KEKB at KEK in Tsukuba Japan, and from new concepts in beam manipulation at the interaction region (IP) called 'crab waist'. This new collider comprises of two colliding beam rings, one at 4.2 GeV and one at 6.7 GeV, a common interaction region, a new injection system at full beam energies, and one of the two beams longitudinally polarized at the IP. Most of the new accelerator techniques needed for this collider have been achieved at other recently completed accelerators including the new PETRA-3 light source at DESY in Hamburg (Germany) and the upgraded DAFNE collider at the INFN laboratory at Frascati (Italy), or during design studies of CLIC or the International Linear Collider (ILC). The project is to be designed and constructed by a worldwide collaboration of accelerator and engineering staff along with ties to industry. To save significant construction costs, many components from the PEP-II collider at SLAC will be recycled and used in this new accelerator. The interaction region will be designed in collaboration with the particle physics detector to guarantee successful mutual use. The accelerator collaboration will consist of several groups at present universities and national

  7. Simulation of Relativistic Shocks and Associated Self-Consistent Radiation

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Niemiec, J.; Medvedev, M.; Zhang, B.; Hardee, P.; Mizuno, Y.; Nordlund, A.; Frederiksen, J.; Sol, H.; Pohl, M.; Hartmann, D. H.; Fishman, J. F.

    2010-01-01

    Plasma instabilities excited in collisionless shocks are responsible for particle acceleration. We have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. These magnetic fields contribute to the electrons transverse deflection behind the shock. We calculate the radiation from deflected electrons in the turbulent magnetic fields. The properties of this radiation may be important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets in general, and supernova remnants.

  8. Simulation of Relativistic Shocks and Associated Self-Consistent Radiation

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Niemiec, J.; Medvedev, M.; Zhang, B.; Hardee, P.; Mizuno, Y.; Nordlund, A.; Frederiksen, J.; Sol, H.; Pohl, M.; Hartmann, D. H.; Fishman, G. J.

    2010-01-01

    Recent PIC simulations of relativistic electron-positron (electron-ion) jets injected into a stationary medium show that particle acceleration occurs at shocked regions. Simulations show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields and particle acceleration. These magnetic fields contribute to the electron's transverse deflection behind the shock. The "jitter" radiation from deflected electrons in turbulent magnetic fields has different properties than synchrotron radiation, which is calculated in a uniform magnetic field. This jitter radiation may be important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets in general, and supernova remnants. We will present detailed spectra for conditions relevant of various astrophysical sites of shock formation via the Weibel instability. In particular we will discuss the application to GRBs and SNRs.

  9. POLARIZED PROTON ACCELERATION IN AGS AND RHIC.

    SciTech Connect

    ROSER,T.

    2007-09-10

    As the first hadron accelerator and collider consisting of two independent superconducting rings RHIC has operated with a wide range of beam energies and particle species including polarized proton beams. The acceleration of polarized beams in both the injector and the collider rings is complicated by numerous depolarizing spin resonances. Partial and full Siberian snakes have made it possible to overcome the depolarization and beam polarizations of up to 65% have been reached at 100 GeV in RHIC.

  10. Space experiments with particle accelerators: SEPAC

    NASA Technical Reports Server (NTRS)

    Roberts, B.

    1986-01-01

    The SEPAC instruments consist of an electron accelerator, a plasma accelerator, a neutral gas (N2) release device, particle and field diagnostic instruments, and a low light level television system. These instruments are used to accomplish multiple experiments: to study beam-particle interactions and other plasma processes; as probes to investigate magnetospheric processes; and as perturbation devices to study energy coupling mechanisms in the magnetosphere, ionosphere, and upper atmosphere.

  11. Acceleration in astrophysics

    SciTech Connect

    Colgate, S.A.

    1993-12-31

    The origin of cosmic rays and applicable laboratory experiments are discussed. Some of the problems of shock acceleration for the production of cosmic rays are discussed in the context of astrophysical conditions. These are: The presumed unique explanation of the power law spectrum is shown instead to be a universal property of all lossy accelerators; the extraordinary isotropy of cosmic rays and the limited diffusion distances implied by supernova induced shock acceleration requires a more frequent and space-filling source than supernovae; the near perfect adiabaticity of strong hydromagnetic turbulence necessary for reflecting the accelerated particles each doubling in energy roughly 10{sup 5} to {sup 6} scatterings with negligible energy loss seems most unlikely; the evidence for acceleration due to quasi-parallel heliosphere shocks is weak. There is small evidence for the expected strong hydromagnetic turbulence, and instead, only a small number of particles accelerate after only a few shock traversals; the acceleration of electrons in the same collisionless shock that accelerates ions is difficult to reconcile with the theoretical picture of strong hydromagnetic turbulence that reflects the ions. The hydromagnetic turbulence will appear adiabatic to the electrons at their much higher Larmor frequency and so the electrons should not be scattered incoherently as they must be for acceleration. Therefore the electrons must be accelerated by a different mechanism. This is unsatisfactory, because wherever electrons are accelerated these sites, observed in radio emission, may accelerate ions more favorably. The acceleration is coherent provided the reconnection is coherent, in which case the total flux, as for example of collimated radio sources, predicts single charge accelerated energies much greater than observed.

  12. Engineered and Administrative Safety Systems for the Control of Prompt Radiation Hazards at Accelerator Facilities

    SciTech Connect

    Liu, James C.; Vylet, Vashek; Walker, Lawrence S.; /SLAC

    2007-12-17

    The ANSI N43.1 Standard, currently in revision (ANSI 2007), sets forth the requirements for accelerator facilities to provide adequate protection for the workers, the public and the environment from the hazards of ionizing radiation produced during and from accelerator operations. The Standard also recommends good practices that, when followed, provide a level of radiation protection consistent with those established for the accelerator communities. The N43.1 Standard is suitable for all accelerator facilities (using electron, positron, proton, or ion particle beams) capable of producing radiation, subject to federal or state regulations. The requirements (see word 'shall') and recommended practices (see word 'should') are prescribed in a graded approach that are commensurate with the complexity and hazard levels of the accelerator facility. Chapters 4, 5 and 6 of the N43.1 Standard address specially the Radiation Safety System (RSS), both engineered and administrative systems, to mitigate and control the prompt radiation hazards from accelerator operations. The RSS includes the Access Control System (ACS) and Radiation Control System (RCS). The main requirements and recommendations of the N43.1 Standard regarding the management, technical and operational aspects of the RSS are described and condensed in this report. Clearly some aspects of the RSS policies and practices at different facilities may differ in order to meet the practical needs for field implementation. A previous report (Liu et al. 2001a), which reviews and summarizes the RSS at five North American high-energy accelerator facilities, as well as the RSS references for the 5 labs (Drozdoff 2001; Gallegos 1996; Ipe and Liu 1992; Liu 1999; Liu 2001b; Rokni 1996; TJNAF 1994; Yotam et al. 1991), can be consulted for the actual RSS implementation at various laboratories. A comprehensive report describing the RSS at the Stanford Linear Accelerator Center (SLAC 2006) can also serve as a reference.

  13. The US Muon Accelerator Program

    SciTech Connect

    Torun, Y.; Kirk, H.; Bross, A.; Geer, Steve; Shiltsev, Vladimir; Zisman, M.; /LBL, Berkeley

    2010-05-01

    An accelerator complex that can produce ultra-intense beams of muons presents many opportunities to explore new physics. A facility of this type is unique in that, in a relatively straightforward way, it can present a physics program that can be staged and thus move forward incrementally, addressing exciting new physics at each step. At the request of the US Department of Energy's Office of High Energy Physics, the Neutrino Factory and Muon Collider Collaboration (NFMCC) and the Fermilab Muon Collider Task Force (MCTF) have recently submitted a proposal to create a Muon Accelerator Program that will have, as a primary goal, to deliver a Design Feasibility Study for an energy-frontier Muon Collider by the end of a 7 year R&D program. This paper presents a description of a Muon Collider facility and gives an overview of the proposal.

  14. Dynamically Reconfigurable Systolic Array Accelerator

    NASA Technical Reports Server (NTRS)

    Dasu, Aravind; Barnes, Robert

    2012-01-01

    A polymorphic systolic array framework has been developed that works in conjunction with an embedded microprocessor on a field-programmable gate array (FPGA), which allows for dynamic and complimentary scaling of acceleration levels of two algorithms active concurrently on the FPGA. Use is made of systolic arrays and a hardware-software co-design to obtain an efficient multi-application acceleration system. The flexible and simple framework allows hosting of a broader range of algorithms, and is extendable to more complex applications in the area of aerospace embedded systems. FPGA chips can be responsive to realtime demands for changing applications needs, but only if the electronic fabric can respond fast enough. This systolic array framework allows for rapid partial and dynamic reconfiguration of the chip in response to the real-time needs of scalability, and adaptability of executables.

  15. Accelerated adaptive integration method.

    PubMed

    Kaus, Joseph W; Arrar, Mehrnoosh; McCammon, J Andrew

    2014-05-15

    Conformational changes that occur upon ligand binding may be too slow to observe on the time scales routinely accessible using molecular dynamics simulations. The adaptive integration method (AIM) leverages the notion that when a ligand is either fully coupled or decoupled, according to λ, barrier heights may change, making some conformational transitions more accessible at certain λ values. AIM adaptively changes the value of λ in a single simulation so that conformations sampled at one value of λ seed the conformational space sampled at another λ value. Adapting the value of λ throughout a simulation, however, does not resolve issues in sampling when barriers remain high regardless of the λ value. In this work, we introduce a new method, called Accelerated AIM (AcclAIM), in which the potential energy function is flattened at intermediate values of λ, promoting the exploration of conformational space as the ligand is decoupled from its receptor. We show, with both a simple model system (Bromocyclohexane) and the more complex biomolecule Thrombin, that AcclAIM is a promising approach to overcome high barriers in the calculation of free energies, without the need for any statistical reweighting or additional processors. PMID:24780083

  16. Accelerated Adaptive Integration Method

    PubMed Central

    2015-01-01

    Conformational changes that occur upon ligand binding may be too slow to observe on the time scales routinely accessible using molecular dynamics simulations. The adaptive integration method (AIM) leverages the notion that when a ligand is either fully coupled or decoupled, according to λ, barrier heights may change, making some conformational transitions more accessible at certain λ values. AIM adaptively changes the value of λ in a single simulation so that conformations sampled at one value of λ seed the conformational space sampled at another λ value. Adapting the value of λ throughout a simulation, however, does not resolve issues in sampling when barriers remain high regardless of the λ value. In this work, we introduce a new method, called Accelerated AIM (AcclAIM), in which the potential energy function is flattened at intermediate values of λ, promoting the exploration of conformational space as the ligand is decoupled from its receptor. We show, with both a simple model system (Bromocyclohexane) and the more complex biomolecule Thrombin, that AcclAIM is a promising approach to overcome high barriers in the calculation of free energies, without the need for any statistical reweighting or additional processors. PMID:24780083

  17. Plasma inverse transition acceleration

    SciTech Connect

    Xie, Ming

    2001-06-18

    It can be proved fundamentally from the reciprocity theorem with which the electromagnetism is endowed that corresponding to each spontaneous process of radiation by a charged particle there is an inverse process which defines a unique acceleration mechanism, from Cherenkov radiation to inverse Cherenkov acceleration (ICA) [1], from Smith-Purcell radiation to inverse Smith-Purcell acceleration (ISPA) [2], and from undulator radiation to inverse undulator acceleration (IUA) [3]. There is no exception. Yet, for nearly 30 years after each of the aforementioned inverse processes has been clarified for laser acceleration, inverse transition acceleration (ITA), despite speculation [4], has remained the least understood, and above all, no practical implementation of ITA has been found, until now. Unlike all its counterparts in which phase synchronism is established one way or the other such that a particle can continuously gain energy from an acceleration wave, the ITA to be discussed here, termed plasma inverse transition acceleration (PITA), operates under fundamentally different principle. As a result, the discovery of PITA has been delayed for decades, waiting for a conceptual breakthrough in accelerator physics: the principle of alternating gradient acceleration [5, 6, 7, 8, 9, 10]. In fact, PITA was invented [7, 8] as one of several realizations of the new principle.

  18. Solving radiation problems at particle accelerators

    SciTech Connect

    Nikolai V. Mokhov

    2001-12-11

    At high-intensity high-energy particle accelerators, consequences of a beam-induced radiation impact on machine and detector components, people, environment and complex performance can range from negligible to severe. The specifics, general approach and tools used at such machines for radiation analysis are described. In particular, the world leader Fermilab accelerator complex is considered, with its fixed target and collider experiments, as well as new challenging projects such as LHC, VLHC, muon collider and neutrino factory. The emphasis is on mitigation of deleterious beam-induced radiation effects and on the key role of effective computer simulations.

  19. Consistent lattice Boltzmann equations for phase transitions.

    PubMed

    Siebert, D N; Philippi, P C; Mattila, K K

    2014-11-01

    Unlike conventional computational fluid dynamics methods, the lattice Boltzmann method (LBM) describes the dynamic behavior of fluids in a mesoscopic scale based on discrete forms of kinetic equations. In this scale, complex macroscopic phenomena like the formation and collapse of interfaces can be naturally described as related to source terms incorporated into the kinetic equations. In this context, a novel athermal lattice Boltzmann scheme for the simulation of phase transition is proposed. The continuous kinetic model obtained from the Liouville equation using the mean-field interaction force approach is shown to be consistent with diffuse interface model using the Helmholtz free energy. Density profiles, interface thickness, and surface tension are analytically derived for a plane liquid-vapor interface. A discrete form of the kinetic equation is then obtained by applying the quadrature method based on prescribed abscissas together with a third-order scheme for the discretization of the streaming or advection term in the Boltzmann equation. Spatial derivatives in the source terms are approximated with high-order schemes. The numerical validation of the method is performed by measuring the speed of sound as well as by retrieving the coexistence curve and the interface density profiles. The appearance of spurious currents near the interface is investigated. The simulations are performed with the equations of state of Van der Waals, Redlich-Kwong, Redlich-Kwong-Soave, Peng-Robinson, and Carnahan-Starling. PMID:25493907

  20. The Dielectric Wall Accelerator

    SciTech Connect

    Caporaso, George J.; Chen, Yu-Jiuan; Sampayan, Stephen E.

    2009-01-01

    The Dielectric Wall Accelerator (DWA), a class of induction accelerators, employs a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge to mass ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.

  1. Particle Simulations of a Linear Dielectric Wall Proton Accelerator

    SciTech Connect

    Poole, B R; Blackfield, D T; Nelson, S D

    2007-06-12

    The dielectric wall accelerator (DWA) is a compact induction accelerator structure that incorporates the accelerating mechanism, pulse forming structure, and switch structure into an integrated module. The DWA consists of stacked stripline Blumlein assemblies, which can provide accelerating gradients in excess of 100 MeV/meter. Blumleins are switched sequentially according to a prescribed acceleration schedule to maintain synchronism with the proton bunch as it accelerates. A finite difference time domain code (FDTD) is used to determine the applied acceleration field to the proton bunch. Particle simulations are used to model the injector as well as the accelerator stack to determine the proton bunch energy distribution, both longitudinal and transverse dynamic focusing, and emittance growth associated with various DWA configurations.

  2. ACCELERATION RESPONSIVE SWITCH

    DOEpatents

    Chabrek, A.F.; Maxwell, R.L.

    1963-07-01

    An acceleration-responsive device with dual channel capabilities whereby a first circuit is actuated upon attainment of a predetermined maximum acceleration level and when the acceleration drops to a predetermined minimum acceleriltion level another circuit is actuated is described. A fluid-damped sensing mass slidably mounted in a relatively frictionless manner on a shaft through the intermediation of a ball bushing and biased by an adjustable compression spring provides inertially operated means for actuating the circuits. (AEC)

  3. Space Acceleration Measurement System

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This training video, presented by the Lewis Research Center's Space Experiments Division, gives a background and detailed instructions for preparing the space acceleration measurement system (SAMS) for use. The SAMS measures, conditions, and records forces of low gravity accelerations, and is used to determine the effect of these forces on various experiments performed in microgravity. Inertial sensors are used to measure positive and negative acceleration over a specified frequency range. The video documents the SAMS' uses in different configurations during shuttle missions.

  4. Wake field accelerators

    SciTech Connect

    Wilson, P.B.

    1986-02-01

    In a wake field accelerator a high current driving bunch injected into a structure or plasma produces intense induced fields, which are in turn used to accelerate a trailing charge or bunch. The basic concepts of wake field acceleration are described. Wake potentials for closed cavities and periodic structures are derived, as are wake potentials on a collinear path with a charge distribution. Cylindrically symmetric structures excited by a beam in the form of a ring are considered. (LEW)

  5. Accelerating into the future

    NASA Astrophysics Data System (ADS)

    Murray, Cherry

    2009-05-01

    Accelerator science has traditionally been associated with high-energy physics and nuclear physics. But the use of accelerators in other areas of science, as well as in medicine and industry, is steadily growing. Accelerators are now, for example, used to treat cancer using proton therapy, which can deposit radiation onto a tumour while causing much less damage to surrounding healthy tissue than with other treatment techniques.

  6. Optically pulsed electron accelerator

    DOEpatents

    Fraser, J.S.; Sheffield, R.L.

    1985-05-20

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  7. Optically pulsed electron accelerator

    DOEpatents

    Fraser, John S.; Sheffield, Richard L.

    1987-01-01

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  8. Miniaturization Techniques for Accelerators

    SciTech Connect

    Spencer, James E.

    2003-05-27

    The possibility of laser driven accelerators [1] suggests the need for new structures based on micromachining and integrated circuit technology because of the comparable scales. Thus, we are exploring fully integrated structures including sources, optics (for both light and particle) and acceleration in a common format--an accelerator-on-chip (AOC). Tests suggest a number of preferred materials and techniques but no technical or fundamental roadblocks at scales of order 1 {micro}m or larger.

  9. Particle acceleration in flares

    NASA Technical Reports Server (NTRS)

    Benz, Arnold O.; Kosugi, Takeo; Aschwanden, Markus J.; Benka, Steve G.; Chupp, Edward L.; Enome, Shinzo; Garcia, Howard; Holman, Gordon D.; Kurt, Victoria G.; Sakao, Taro

    1994-01-01

    Particle acceleration is intrinsic to the primary energy release in the impulsive phase of solar flares, and we cannot understand flares without understanding acceleration. New observations in soft and hard X-rays, gamma-rays and coherent radio emissions are presented, suggesting flare fragmentation in time and space. X-ray and radio measurements exhibit at least five different time scales in flares. In addition, some new observations of delayed acceleration signatures are also presented. The theory of acceleration by parallel electric fields is used to model the spectral shape and evolution of hard X-rays. The possibility of the appearance of double layers is further investigated.

  10. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-09-02

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  11. Accelerator-based BNCT.

    PubMed

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases. PMID:24365468

  12. Acceleration of polarized protons in circular accelerators

    SciTech Connect

    Courant, E.D.; Ruth, R.D.

    1980-09-12

    The theory of depolarization in circular accelerators is presented. The spin equation is first expressed in terms of the particle orbit and then converted to the equivalent spinor equation. The spinor equation is then solved for three different situations: (1) a beam on a flat top near a resonance, (2) uniform acceleration through an isolated resonance, and (3) a model of a fast resonance jump. Finally, the depolarization coefficient, epsilon, is calculated in terms of properties of the particle orbit and the results are applied to a calculation of depolarization in the AGS.

  13. Prospects and limitations of cyclotron resonance laser acceleration

    SciTech Connect

    Chen, C. )

    1992-07-01

    The cyclotron resonance laser (CRL) accelerator is a novel concept of accelerating continuous charged-particle beams to moderately or highly relativistic energies. This paper discusses prospects and limitations of this concept. In particular, a three-dimensional, self-consistent theory is used to analyze the nonlinear interaction of an electron beam with an intense traveling electromagnetic wave in such an accelerator. The parameter regimes of experimental interest are identified on the basis of scaling calculations. The results of simulation modeling of a multimegavolt electron CRL accelerator are presented. The possibility of building continuous-wave (cw) CRL accelerators is discussed.

  14. [Psychometric properties of a scale: internal consistency].

    PubMed

    Campo-Arias, Adalberto; Oviedo, Heidi C

    2008-01-01

    Internal consistency reliability is the degree of correlation between a scale's items. Internal consistency is calculated by Kuder-Richardson's formula 20 for dichotomous choices and Cronbach's alpha for polytomous items. 0.70 to 0.90 internal consistency is acceptable. 5-25 participants are needed for each item when computing the internal consistency of a twenty-item scale. Internal consistency varies according to population and then it is necessary to report it always that scale is used. PMID:19360231

  15. Particle Acceleration in Active Galactic Nuclei

    NASA Technical Reports Server (NTRS)

    Miller, James A.

    1996-01-01

    The investigation of stochastic particle acceleration through resonant interactions with plasma waves that populate the magnetosphere surrounding an accreting black hole is presented. Stochastic acceleration has been successfully applied to the problem of ion and electron energization in solar flares, and is capable of accounting for a wide range of both neutral and charged particle emissions. It is also a component in diffusive shock acceleration, since pitch-angle scattering (which is necessary for multiple shock crossings) is accompanied by diffusion in momentum space, which in turn yields a net systematic energy gain; however, stochastic energization will dominate the first-order shock process only in certain parameter regimes. Although stochastic acceleration has been applied to particle energization in the lobes of radio galaxies, its application to the central regions of AGNs (active galactic nuclei) has only recently been considered, but not in detail. We proposed to systematically investigate the plasma processes responsible for stochastic particle acceleration in black hole magnetospheres along with the energy-loss processes which impede particle energization. To this end, we calculated acceleration rates and escape time scales for protons and electrons resonating with Alfven waves, and for electrons resonating with whistlers. We also considered the "hot" topic of gamma-ray line emission from the Orion complex. We proposed that the observed gamma-ray lines are produced by energetic ions that are stochastically accelerated by cascading Alfven waves in the accretion plasma near a black hole. Related research papers that were published in journals are listed.

  16. Measurement of Coriolis Acceleration with a Smartphone

    NASA Astrophysics Data System (ADS)

    Shakur, Asif; Kraft, Jakob

    2016-05-01

    Undergraduate physics laboratories seldom have experiments that measure the Coriolis acceleration. This has traditionally been the case owing to the inherent complexities of making such measurements. Articles on the experimental determination of the Coriolis acceleration are few and far between in the physics literature. However, because modern smartphones come with a raft of built-in sensors, we have a unique opportunity to experimentally determine the Coriolis acceleration conveniently in a pedagogically enlightening environment at modest cost by using student-owned smartphones. Here we employ the gyroscope and accelerometer in a smartphone to verify the dependence of Coriolis acceleration on the angular velocity of a rotatingtrack and the speed of the sliding smartphone.

  17. Scaling FFAG accelerator for muon acceleration

    SciTech Connect

    Lagrange, JB.; Planche, T.; Mori, Y.

    2011-10-06

    Recent developments in scaling fixed field alternating gradient (FFAG) accelerators have opened new ways for lattice design, with straight sections, and insertions like dispersion suppressors. Such principles and matching issues are detailed in this paper. An application of these new concepts is presented to overcome problems in the PRISM project.

  18. Angular velocities, angular accelerations, and coriolis accelerations

    NASA Technical Reports Server (NTRS)

    Graybiel, A.

    1975-01-01

    Weightlessness, rotating environment, and mathematical analysis of Coriolis acceleration is described for man's biological effective force environments. Effects on the vestibular system are summarized, including the end organs, functional neurology, and input-output relations. Ground-based studies in preparation for space missions are examined, including functional tests, provocative tests, adaptive capacity tests, simulation studies, and antimotion sickness.

  19. Accelerator neutrino program at Fermilab

    SciTech Connect

    Parke, Stephen J.; /Fermilab

    2010-05-01

    The accelerator neutrino programme in the USA consists primarily of the Fermilab neutrino programme. Currently, Fermilab operates two neutrino beamlines, the Booster neutrino beamline and the NuMI neutrino beamline and is the planning stages for a third neutrino beam to send neutrinos to DUSEL. The experiments in the Booster neutrino beamline are miniBooNE, SciBooNE and in the future microBooNE, whereas in the NuMI beamline we have MINOS, ArgoNut, MINERVA and coming soon NOvA. The major experiment in the beamline to DUSEL will be LBNE.

  20. GPU-Accelerated Text Mining

    SciTech Connect

    Cui, Xiaohui; Mueller, Frank; Zhang, Yongpeng; Potok, Thomas E

    2009-01-01

    Accelerating hardware devices represent a novel promise for improving the performance for many problem domains but it is not clear for which domains what accelerators are suitable. While there is no room in general-purpose processor design to significantly increase the processor frequency, developers are instead resorting to multi-core chips duplicating conventional computing capabilities on a single die. Yet, accelerators offer more radical designs with a much higher level of parallelism and novel programming environments. This present work assesses the viability of text mining on CUDA. Text mining is one of the key concepts that has become prominent as an effective means to index the Internet, but its applications range beyond this scope and extend to providing document similarity metrics, the subject of this work. We have developed and optimized text search algorithms for GPUs to exploit their potential for massive data processing. We discuss the algorithmic challenges of parallelization for text search problems on GPUs and demonstrate the potential of these devices in experiments by reporting significant speedups. Our study may be one of the first to assess more complex text search problems for suitability for GPU devices, and it may also be one of the first to exploit and report on atomic instruction usage that have recently become available in NVIDIA devices.

  1. Accelerators (4/5)

    ScienceCinema

    None

    2011-10-06

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  2. Particle Acceleration in Jets

    NASA Technical Reports Server (NTRS)

    Nishikawa, Ken-Ichi

    2005-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma ray burst (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Fermi acceleration is the mechanism usually assumed for the acceleration of particles in astrophysical environments.

  3. Diagnostics for induction accelerators

    SciTech Connect

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960`s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore`s Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail.

  4. Accelerators Beyond The Tevatron?

    SciTech Connect

    Lach, Joseph

    2010-07-01

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?

  5. Microscale acceleration history discriminators

    DOEpatents

    Polosky, Marc A.; Plummer, David W.

    2002-01-01

    A new class of micromechanical acceleration history discriminators is claimed. These discriminators allow the precise differentiation of a wide range of acceleration-time histories, thereby allowing adaptive events to be triggered in response to the severity (or lack thereof) of an external environment. Such devices have applications in airbag activation, and other safety and surety applications.

  6. KEK digital accelerator

    NASA Astrophysics Data System (ADS)

    Iwashita, T.; Adachi, T.; Takayama, K.; Leo, K. W.; Arai, T.; Arakida, Y.; Hashimoto, M.; Kadokura, E.; Kawai, M.; Kawakubo, T.; Kubo, Tomio; Koyama, K.; Nakanishi, H.; Okazaki, K.; Okamura, K.; Someya, H.; Takagi, A.; Tokuchi, A.; Wake, M.

    2011-07-01

    The High Energy Accelerator Research Organization KEK digital accelerator (KEK-DA) is a renovation of the KEK 500 MeV booster proton synchrotron, which was shut down in 2006. The existing 40 MeV drift tube linac and rf cavities have been replaced by an electron cyclotron resonance (ECR) ion source embedded in a 200 kV high-voltage terminal and induction acceleration cells, respectively. A DA is, in principle, capable of accelerating any species of ion in all possible charge states. The KEK-DA is characterized by specific accelerator components such as a permanent magnet X-band ECR ion source, a low-energy transport line, an electrostatic injection kicker, an extraction septum magnet operated in air, combined-function main magnets, and an induction acceleration system. The induction acceleration method, integrating modern pulse power technology and state-of-art digital control, is crucial for the rapid-cycle KEK-DA. The key issues of beam dynamics associated with low-energy injection of heavy ions are beam loss caused by electron capture and stripping as results of the interaction with residual gas molecules and the closed orbit distortion resulting from relatively high remanent fields in the bending magnets. Attractive applications of this accelerator in materials and biological sciences are discussed.

  7. Accelerators (5/5)

    ScienceCinema

    None

    2011-10-06

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  8. Accelerating global forest mortality

    NASA Astrophysics Data System (ADS)

    McDowell, N. G.

    2014-12-01

    Forest mortality is apparently accelerating globally. The evidence supporting this contention is now substantial, as is the evidence suggesting the acceleration has just begun and will become progressively worse in upcoming decades. I will review the data and models used to make these contentions.

  9. Accelerators (3/5)

    ScienceCinema

    None

    2011-10-06

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  10. Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams

    SciTech Connect

    Siemann, R.H.; /SLAC

    2011-10-24

    Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.

  11. Centrifugal acceleration in the magnetotail lobes

    NASA Astrophysics Data System (ADS)

    Nilsson, H.; Engwall, E.; Eriksson, A.; Puhl-Quinn, P. A.; Arvelius, S.

    2010-02-01

    Combined Cluster EFW and EDI measurements have shown that cold ion outflow in the magnetospheric lobes dominates the hydrogen ion outflow from the Earth's atmosphere. The ions have too low kinetic energy to be measurable with particle instruments, at least for the typical spacecraft potential of a sunlit spacecraft in the tenuous lobe plasmas outside a few RE. The measurement technique yields both density and bulk velocity, which can be combined with magnetic field measurements to estimate the centrifugal acceleration experienced by these particles. We present a quantitative estimate of the centrifugal acceleration, and the velocity change with distance which we would expect due to centrifugal acceleration. It is found that the centrifugal acceleration is on average outward with an average value of about of 5 m s-2. This is small, but acting during long transport times and over long distances the cumulative effect is significant, while still consistent with the relatively low velocities estimated using the combination of EFW and EDI data. The centrifugal acceleration should accelerate any oxygen ions in the lobes to energies observable by particle spectrometers. The data set also put constraints on the effectiveness of any other acceleration mechanisms acting in the lobes, where the total velocity increase between 5 and 19 RE geocentric distance is less than 5 km s-1.

  12. Accelerated glass reaction under PCT conditions

    SciTech Connect

    Ebert, W.L.; Bates, J.K.; Buck, E.C.; Bradley, C.R.

    1992-01-01

    Static leach tests similar to PCT (Product Consistency Test) were performed for up to 2 years to assess long-term reaction behavior of high-level nuclear waste glasses similar to those at Defense Waste Processing Facility. These tests show the reaction rate to decrease with the reaction time from an initially high rate to a low rate, but then to accelerate to a higher rate after reaction times of about 1 year, depending on glass surface area/leachant volume ratio used. Solution concentrations of soluble glass components increase as the reaction is accelerated, while release of other glass components into solution is controlled by secondary phases. Net result is that transformation of glass to stable phases is accelerated while the solution becomes enriched in soluble components not effectively contained in secondary phases. Rate becomes linear in time after the acceleration and may be similar to the initial forward rate. A current model of glass reaction predicts that the glass reaction will be accelerated upon the formation of secondary phases which lower the silicic acid solution concentration. These tests show total Si concentration to increase upon reaction acceleration, however, which may be due to the slightly higher pH attained with the acceleration. The sudden change in the reaction rate is likely due to secondary phase formation. 17 refs, 2 tabs, 3 figs.

  13. Accelerated glass reaction under PCT conditions

    SciTech Connect

    Ebert, W.L.; Bates, J.K.; Buck, E.C.; Bradley, C.R.

    1992-12-31

    Static leach tests similar to PCT (Product Consistency Test) were performed for up to 2 years to assess long-term reaction behavior of high-level nuclear waste glasses similar to those at Defense Waste Processing Facility. These tests show the reaction rate to decrease with the reaction time from an initially high rate to a low rate, but then to accelerate to a higher rate after reaction times of about 1 year, depending on glass surface area/leachant volume ratio used. Solution concentrations of soluble glass components increase as the reaction is accelerated, while release of other glass components into solution is controlled by secondary phases. Net result is that transformation of glass to stable phases is accelerated while the solution becomes enriched in soluble components not effectively contained in secondary phases. Rate becomes linear in time after the acceleration and may be similar to the initial forward rate. A current model of glass reaction predicts that the glass reaction will be accelerated upon the formation of secondary phases which lower the silicic acid solution concentration. These tests show total Si concentration to increase upon reaction acceleration, however, which may be due to the slightly higher pH attained with the acceleration. The sudden change in the reaction rate is likely due to secondary phase formation. 17 refs, 2 tabs, 3 figs.

  14. Cascaded radiation pressure acceleration

    SciTech Connect

    Pei, Zhikun; Shen, Baifei E-mail: zhxm@siom.ac.cn; Zhang, Xiaomei E-mail: zhxm@siom.ac.cn; Wang, Wenpeng; Zhang, Lingang; Yi, Longqing; Shi, Yin; Xu, Zhizhan

    2015-07-15

    A cascaded radiation-pressure acceleration scheme is proposed. When an energetic proton beam is injected into an electrostatic field moving at light speed in a foil accelerated by light pressure, protons can be re-accelerated to much higher energy. An initial 3-GeV proton beam can be re-accelerated to 7 GeV while its energy spread is narrowed significantly, indicating a 4-GeV energy gain for one acceleration stage, as shown in one-dimensional simulations and analytical results. The validity of the method is further confirmed by two-dimensional simulations. This scheme provides a way to scale proton energy at the GeV level linearly with laser energy and is promising to obtain proton bunches at tens of gigaelectron-volts.

  15. Accelerated testing of space mechanisms

    NASA Technical Reports Server (NTRS)

    Murray, S. Frank; Heshmat, Hooshang

    1995-01-01

    This report contains a review of various existing life prediction techniques used for a wide range of space mechanisms. Life prediction techniques utilized in other non-space fields such as turbine engine design are also reviewed for applicability to many space mechanism issues. The development of new concepts on how various tribological processes are involved in the life of the complex mechanisms used for space applications are examined. A 'roadmap' for the complete implementation of a tribological prediction approach for complex mechanical systems including standard procedures for test planning, analytical models for life prediction and experimental verification of the life prediction and accelerated testing techniques are discussed. A plan is presented to demonstrate a method for predicting the life and/or performance of a selected space mechanism mechanical component.

  16. Acceleration of black hole universe

    NASA Astrophysics Data System (ADS)

    Zhang, T. X.; Frederick, C.

    2014-01-01

    Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.

  17. The BNL Accelerator Test Facility control system

    SciTech Connect

    Malone, R.; Bottke, I.; Fernow, R.; Ben-Zvi, I.

    1993-01-01

    Described is the VAX/CAMAC-based control system for Brookhaven National Laboratory's Accelerator Test Facility, a laser/linac research complex. Details of hardware and software configurations are presented along with experiences of using Vsystem, a commercial control system package.

  18. Relationship Dynamics and Consistency of Condom Use among Adolescents

    PubMed Central

    Manning, Wendy D.; Flanigan, Christine M.; Giordano, Peggy C.; Longmore, Monica A.

    2011-01-01

    Context Research on teen condom use often focuses on the influence of parents, peers, and environmental factors. Although most sexually active teens have sex within dating relationships, we know little about how the characteristics of dating relationships are associated with consistent condom use. Methods Data on 269 teens in Wave 1 of the Toledo Adolescent Relationship Study who had sex in their most recent relationships were analyzed to examine how qualities of their relationship are associated with condom use. We present odds ratios based on logistic regression models predicting consistent condom use. Results Drawing on the analytic sample of teens who had sex with their dating partner, relationship qualities were significantly related to consistent condom use. Both negative relationship dynamics (conflict, control, mistrust, jealousy, perceived partner inferiority) and positive qualities (love, enmeshment, salience, self-disclosure) were associated with consistent condom use (OR .65–.89). Similar to prior studies, demographic asymmetries (age, race, neighborhood) were not related to consistent condom use. Relationship duration was negatively associated with consistent condom use (OR .98–.99), but the effect of duration was explained by feelings of relationship importance. The role of relationship qualities was similar for males and females. Conclusions Although the relationship processes associated with consistent condom use are complex, such processes appeared to be more strongly associated with consistent condom use than were sociodemographic characteristics. The findings suggested programs should focus on relationship qualities and dynamics, recognizing that both negative and positive relationship features were associated with consistent condom use. PMID:19740237

  19. Compact RF ion source for industrial electrostatic ion accelerator.

    PubMed

    Kwon, Hyeok-Jung; Park, Sae-Hoon; Kim, Dae-Il; Cho, Yong-Sub

    2016-02-01

    Korea Multi-purpose Accelerator Complex is developing a single-ended electrostatic ion accelerator to irradiate gaseous ions, such as hydrogen and nitrogen, on materials for industrial applications. ELV type high voltage power supply has been selected. Because of the limited space, electrical power, and robust operation, a 200 MHz RF ion source has been developed. In this paper, the accelerator system, test stand of the ion source, and its test results are described. PMID:26932115

  20. Compact RF ion source for industrial electrostatic ion accelerator

    NASA Astrophysics Data System (ADS)

    Kwon, Hyeok-Jung; Park, Sae-Hoon; Kim, Dae-Il; Cho, Yong-Sub

    2016-02-01

    Korea Multi-purpose Accelerator Complex is developing a single-ended electrostatic ion accelerator to irradiate gaseous ions, such as hydrogen and nitrogen, on materials for industrial applications. ELV type high voltage power supply has been selected. Because of the limited space, electrical power, and robust operation, a 200 MHz RF ion source has been developed. In this paper, the accelerator system, test stand of the ion source, and its test results are described.

  1. A Procedure for Estimating Intrasubject Behavior Consistency

    ERIC Educational Resources Information Center

    Hernandez, Jose M.; Rubio, Victor J.; Revuelta, Javier; Santacreu, Jose

    2006-01-01

    Trait psychology implicitly assumes consistency of the personal traits. Mischel, however, argued against the idea of a general consistency of human beings. The present article aims to design a statistical procedure based on an adaptation of the pi* statistic to measure the degree of intraindividual consistency independently of the measure used.…

  2. 15 CFR 930.57 - Consistency certifications.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT FEDERAL CONSISTENCY WITH APPROVED COASTAL MANAGEMENT PROGRAMS Consistency for Activities Requiring... consistent with the management program. At the same time, the applicant shall furnish to the State agency...

  3. Operation of the accelerator

    SciTech Connect

    Pardo, R.C.; Batzka, B.; Billquist, P.J.

    1995-08-01

    Fiscal Year 1994 was the first year of seven-day operation since ATLAS became a national user facility in 1985. ATLAS made the most of the opportunity this year by providing 5200 hours of beam on-target to the research program. A record number of 60 experiments were completed and the {open_quotes}facility reliability{close_quotes} remained near the 90% level. Seven-day operation was made possible with the addition to the staff of two operator positions providing single-operator coverage during the weekend period. The normally scheduled coverage was augmented by an on-call list of system experts who respond to emergencies with phone-in advice and return to the Laboratory when necessary. This staffing approach continues but we rearranged our staffing patterns so that we now have one cryogenics engineer working a shift pattern which includes 8-hour daily coverage during the weekend. ATLAS provided a beam mix to users consisting of 26 different isotopic species, 23% of which were for A>100 in FY 1994. Approximately 60% of the beam time was provided by the Positive Ion Injector, slightly less than the usage rate of FY 1993. Experiments using uranium or lead beams accounted for 16.4% of the total beam time. The ECR ion source and high-voltage platform functioned well throughout the year. A new technique for solid material production in the source was developed which uses a sputtering process wherein the sample of material placed near the plasma chamber wall is biased negatively. Plasma ions are accelerated into the sample and material is sputtered from the surface into the plasma. This technique is now used routinely for many elements. Runs of calcium, germanium, nickel, lead, tellurium, and uranium were carried out with this technique.

  4. Analyzing radial acceleration with a smartphone acceleration sensor

    NASA Astrophysics Data System (ADS)

    Vogt, Patrik; Kuhn, Jochen

    2013-03-01

    This paper continues the sequence of experiments using the acceleration sensor of smartphones (for description of the function and the use of the acceleration sensor, see Ref. 1) within this column, in this case for analyzing the radial acceleration.

  5. Simulation of electron post-acceleration in a two-stage laser Wakefield accelerator

    SciTech Connect

    Reitsma, A.J.W.; Leemans, W.P.; Esarey, E.; Kamp, L.P.J.; Schep, T.J.

    2002-04-01

    Electron bunches produced in self-modulated laser wakefield experiments usually have a broad energy spectrum, with most electrons at low energy (1-3 MeV) and only a small fraction at high energy. We propose and investigate further acceleration of such bunches in a channel-guided resonant laser wakefield accelerator. Two-dimensional simulations with and without the effects of self-consistent beam loading are performed and compared. These results indicate that it is possible to trap about 40 percent of the injected bunch charge and accelerate this fraction to an average energy of about 50 MeV in a plasma channel of a few mn.

  6. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, Graeme (Inventor)

    1984-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids (16, 18) with multiple pairs of aligned holes positioned to direct a group of beamlets (20) along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam (14). An accelerator electrode device (22) downstream from the extraction grids, is at a much lower potential than the grids to accelerate the combined beam.

  7. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, G. (Inventor)

    1981-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids with multiple pairs of aligned holes positioned to direct a group of beamlets along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam. An accelerator electrode device downstream from the extraction grids is at a much lower potential than the grids to accelerate the combined beam. The application of the system to ion implantation is mentioned.

  8. The MESA accelerator

    SciTech Connect

    Aulenbacher, Kurt

    2013-11-07

    The MESA accelerator will operate for particle and nuclear physics experiments in two different modes. A first option is conventional c.w. acceleration yielding 150-200MeV spin-polarized external beam. Second, MESA will be operated as a superconducting multi-turn energy recovery linac (ERL), opening the opportunity to perform experiments with a windowless target with beam current of up to 10 mA. The perspectives for innovative experiments with such a machine are discussed together with a sketch of the accelerator physics issues that have to be solved.

  9. Confronting Twin Paradox Acceleration

    NASA Astrophysics Data System (ADS)

    Murphy, Thomas W.

    2016-05-01

    The resolution to the classic twin paradox in special relativity rests on the asymmetry of acceleration. Yet most students are not exposed to a satisfactory analysis of what exactly happens during the acceleration phase that results in the nonaccelerated observer's more rapid aging. The simple treatment presented here offers both graphical and quantitative solutions to the problem, leading to the correct result that the acceleration-induced age gap is 2Lβ years when the one-way distance L is expressed in light-years and velocity β ≡v/c .

  10. Accelerator Toolbox for MATLAB

    SciTech Connect

    Terebilo, Andrei

    2001-05-29

    This paper introduces Accelerator Toolbox (AT)--a collection of tools to model particle accelerators and beam transport lines in the MATLAB environment. At SSRL, it has become the modeling code of choice for the ongoing design and future operation of the SPEAR 3 synchrotron light source. AT was designed to take advantage of power and simplicity of MATLAB--commercially developed environment for technical computing and visualization. Many examples in this paper illustrate the advantages of the AT approach and contrast it with existing accelerator code frameworks.

  11. Twisted waveguide accelerating structure.

    SciTech Connect

    Kang, Y. W.

    2000-08-15

    A hollow waveguide with a uniform cross section may be used for accelerating charged particles if the phase velocity of an accelerating mode is equal to or less than the free space speed of light. Regular straight hollow waveguides have phase velocities of propagating electromagnetic waves greater than the free-space speed of light. if the waveguide is twisted, the phase velocities of the waveguide modes become slower. The twisted waveguide structure has been modeled and computer simulated in 3-D electromagnetic solvers to show the slow-wave properties for the accelerating mode.

  12. PARTS: (Plasma Accelerated Reusable Transport System)

    NASA Astrophysics Data System (ADS)

    Aherne, Michael; Davis, Phil; England, Matt; Gustavsson, Jake; Pankow, Steve; Sampaio, Chere; Savella, Phil

    2002-01-01

    The Plasma Accelerated Reusable Transport System (PARTS) is an unmanned cargo shuttle intended to ferry large payloads to and from Martian orbit using a highly efficient VAriable Specific Impulse Magnetoplasma Rocket (VASIMR). The design of PARTS focuses on balancing cost and minimizing transit time for a chosen payload consisting of vehicles, satellites, and other components provided by interested parties.

  13. Newton's Laws: A Very Persistent Consistency

    ERIC Educational Resources Information Center

    Viennot, Laurence

    2012-01-01

    This note is a response to a recent paper by McClelland (2011 "Phys. Educ." 46 469-471). The situation of a person who is walking horizontally along the ground is examined, and the statement "The person is accelerated by a net force from the Earth" is considered invalid. A key point in McClelland's analysis is his claim that: "The force…

  14. The temporal relationship between infant heart rate acceleration and crying in an aversive situation.

    PubMed

    Vaughn, B; Sroufe, L A

    1979-06-01

    The temporal relationship between heart rate (HR) acceleration and crying was examined in 16 8-16-month-old infants. Consistently, the HR acceleration began well before the onset of crying, suggesting that such acceleration is not merely a by-product of crying. The accelerations observed were above and beyond a return to baseline following orienting. The crying itself validates the association between these instances of HR acceleration and negative effect. PMID:487890

  15. Status and Future Developments in Large Accelerator Control Systems

    SciTech Connect

    Karen S. White

    2006-10-31

    Over the years, accelerator control systems have evolved from small hardwired systems to complex computer controlled systems with many types of graphical user interfaces and electronic data processing. Today's control systems often include multiple software layers, hundreds of distributed processors, and hundreds of thousands of lines of code. While it is clear that the next generation of accelerators will require much bigger control systems, they will also need better systems. Advances in technology will be needed to ensure the network bandwidth and CPU power can provide reasonable update rates and support the requisite timing systems. Beyond the scaling problem, next generation systems face additional challenges due to growing cyber security threats and the likelihood that some degree of remote development and operation will be required. With a large number of components, the need for high reliability increases and commercial solutions can play a key role towards this goal. Future control systems will operate more complex machines and need to present a well integrated, interoperable set of tools with a high degree of automation. Consistency of data presentation and exception handling will contribute to efficient operations. From the development perspective, engineers will need to provide integrated data management in the beginning of the project and build adaptive software components around a central data repository. This will make the system maintainable and ensure consistency throughout the inevitable changes during the machine lifetime. Additionally, such a large project will require professional project management and disciplined use of well-defined engineering processes. Distributed project teams will make the use of standards, formal requirements and design and configuration control vital. Success in building the control system of the future may hinge on how well we integrate commercial components and learn from best practices used in other industries.

  16. CLASHING BEAM PARTICLE ACCELERATOR

    DOEpatents

    Burleigh, R.J.

    1961-04-11

    A charged-particle accelerator of the proton synchrotron class having means for simultaneously accelerating two separate contra-rotating particle beams within a single annular magnet structure is reported. The magnet provides two concentric circular field regions of opposite magnetic polarity with one field region being of slightly less diameter than the other. The accelerator includes a deflector means straddling the two particle orbits and acting to collide the two particle beams after each has been accelerated to a desired energy. The deflector has the further property of returning particles which do not undergo collision to the regular orbits whereby the particles recirculate with the possibility of colliding upon subsequent passages through the deflector.

  17. Accelerator on a Chip

    SciTech Connect

    England, Joel

    2014-06-30

    SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

  18. Non-accelerator experiments

    SciTech Connect

    Goldhaber, M.

    1986-01-01

    This report discusses several topics which can be investigated without the use of accelerators. Topics covered are: (1) proton decay, (2) atmospheric neutrinos, (3) neutrino detection, (4) muons from Cygnus X-3, and (5) the double-beta decay.

  19. Principles of Induction Accelerators

    NASA Astrophysics Data System (ADS)

    Briggs*, Richard J.

    The basic concepts involved in induction accelerators are introduced in this chapter. The objective is to provide a foundation for the more detailed coverage of key technology elements and specific applications in the following chapters. A wide variety of induction accelerators are discussed in the following chapters, from the high current linear electron accelerator configurations that have been the main focus of the original developments, to circular configurations like the ion synchrotrons that are the subject of more recent research. The main focus in the present chapter is on the induction module containing the magnetic core that plays the role of a transformer in coupling the pulsed power from the modulator to the charged particle beam. This is the essential common element in all these induction accelerators, and an understanding of the basic processes involved in its operation is the main objective of this chapter. (See [1] for a useful and complementary presentation of the basic principles in induction linacs.)

  20. Accelerator on a Chip

    ScienceCinema

    England, Joel

    2014-07-16

    SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

  1. Rare Isotope Accelerators

    NASA Astrophysics Data System (ADS)

    Savard, Guy

    2002-04-01

    The next frontier for low-energy nuclear physics involves experimentation with accelerated beams of short-lived radioactive isotopes. A new facility, the Rare Isotope Accelerator (RIA), is proposed to produce large amount of these rare isotopes and post-accelerate them to energies relevant for studies in nuclear physics, astrophysics and the study of fundamental interactions at low energy. The basic science motivation for this facility will be introduced. The general facility layout, from the 400 kW heavy-ion superconducting linac used for production of the required isotopes to the novel production and extraction schemes and the highly efficient post-accelerator, will be presented. Special emphasis will be put on a number of technical breakthroughs and recent R&D results that enable this new facility.

  2. Vibration control in accelerators

    SciTech Connect

    Montag, C.

    2011-01-01

    In the vast majority of accelerator applications, ground vibration amplitudes are well below tolerable magnet jitter amplitudes. In these cases, it is necessary and sufficient to design a rigid magnet support structure that does not amplify ground vibration. Since accelerator beam lines are typically installed at an elevation of 1-2m above ground level, special care has to be taken in order to avoid designing a support structure that acts like an inverted pendulum with a low resonance frequency, resulting in untolerable lateral vibration amplitudes of the accelerator components when excited by either ambient ground motion or vibration sources within the accelerator itself, such as cooling water pumps or helium flow in superconducting magnets. In cases where ground motion amplitudes already exceed the required jiter tolerances, for instance in future linear colliders, passive vibration damping or active stabilization may be considered.

  3. Charged particle accelerator grating

    DOEpatents

    Palmer, R.B.

    1985-09-09

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams onto the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  4. Accelerator vibration issues

    SciTech Connect

    Tennant, R.A.

    1985-01-01

    Vibrations induced in accelerator structures can cause particle-beam jitter and alignment difficulties. Sources of these vibrations may include pump oscillations, cooling-water turbulence, and vibrations transmitted through the floor to the accelerator structure. Drift tubes (DT) in a drift tube linac (DTL) are components likely to affect beam jitter and alignment because they normally have a heavy magnet structure on the end of a long and relatively small support stem. The natural vibrational frequencies of a drift tube have been compared with theoretical predictions. In principle, by knowing natural frequencies of accelerator components and system vibrational frequncies, an accelerator can be designed that does not have these frequencies coinciding. 2 refs., 2 figs., 2 tabs.

  5. Efficient self-consistent quantum transport simulator for quantum devices

    SciTech Connect

    Gao, X. Mamaluy, D.; Nielsen, E.; Young, R. W.; Lilly, M. P.; Bishop, N. C.; Carroll, M. S.; Muller, R. P.; Shirkhorshidian, A.

    2014-04-07

    We present a self-consistent one-dimensional (1D) quantum transport simulator based on the Contact Block Reduction (CBR) method, aiming for very fast and robust transport simulation of 1D quantum devices. Applying the general CBR approach to 1D open systems results in a set of very simple equations that are derived and given in detail for the first time. The charge self-consistency of the coupled CBR-Poisson equations is achieved by using the predictor-corrector iteration scheme with the optional Anderson acceleration. In addition, we introduce a new way to convert an equilibrium electrostatic barrier potential calculated from an external simulator to an effective doping profile, which is then used by the CBR-Poisson code for transport simulation of the barrier under non-zero biases. The code has been applied to simulate the quantum transport in a double barrier structure and across a tunnel barrier in a silicon double quantum dot. Extremely fast self-consistent 1D simulations of the differential conductance across a tunnel barrier in the quantum dot show better qualitative agreement with experiment than non-self-consistent simulations.

  6. Efficient self-consistent quantum transport simulator for quantum devices

    NASA Astrophysics Data System (ADS)

    Gao, X.; Mamaluy, D.; Nielsen, E.; Young, R. W.; Shirkhorshidian, A.; Lilly, M. P.; Bishop, N. C.; Carroll, M. S.; Muller, R. P.

    2014-04-01

    We present a self-consistent one-dimensional (1D) quantum transport simulator based on the Contact Block Reduction (CBR) method, aiming for very fast and robust transport simulation of 1D quantum devices. Applying the general CBR approach to 1D open systems results in a set of very simple equations that are derived and given in detail for the first time. The charge self-consistency of the coupled CBR-Poisson equations is achieved by using the predictor-corrector iteration scheme with the optional Anderson acceleration. In addition, we introduce a new way to convert an equilibrium electrostatic barrier potential calculated from an external simulator to an effective doping profile, which is then used by the CBR-Poisson code for transport simulation of the barrier under non-zero biases. The code has been applied to simulate the quantum transport in a double barrier structure and across a tunnel barrier in a silicon double quantum dot. Extremely fast self-consistent 1D simulations of the differential conductance across a tunnel barrier in the quantum dot show better qualitative agreement with experiment than non-self-consistent simulations.

  7. Breakthrough: Fermilab Accelerator Technology

    ScienceCinema

    None

    2014-08-12

    There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

  8. Rolamite acceleration sensor

    DOEpatents

    Abbin, Joseph P.; Briner, Clifton F.; Martin, Samuel B.

    1993-01-01

    A rolamite acceleration sensor which has a failsafe feature including a housing, a pair of rollers, a tension band wrapped in an S shaped fashion around the rollers, wherein the band has a force-generation cut out and a failsafe cut out or weak portion. The failsafe cut out or weak portion breaks when the sensor is subjected to an excessive acceleration so that the sensor fails in an open circuit (non-conducting) state permanently.

  9. Rolamite acceleration sensor

    DOEpatents

    Abbin, J.P.; Briner, C.F.; Martin, S.B.

    1993-12-21

    A rolamite acceleration sensor is described which has a failsafe feature including a housing, a pair of rollers, a tension band wrapped in an S shaped fashion around the rollers, wherein the band has a force-generation cut out and a failsafe cut out or weak portion. The failsafe cut out or weak portion breaks when the sensor is subjected to an excessive acceleration so that the sensor fails in an open circuit (non-conducting) state permanently. 6 figures.

  10. Microgravity Acceleration Measurement System

    NASA Technical Reports Server (NTRS)

    Foster, William

    2009-01-01

    Microgravity Acceleration Measurement System (MAMS) is an ongoing study of the small forces (vibrations and accelerations) on the ISS that result from the operation of hardware, crew activities, as well as dockings and maneuvering. Results will be used to generalize the types of vibrations affecting vibration-sensitive experiments. Investigators seek to better understand the vibration environment on the space station to enable future research.

  11. Breakthrough: Fermilab Accelerator Technology

    SciTech Connect

    2012-04-23

    There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

  12. Collective field accelerator

    DOEpatents

    Luce, John S.

    1978-01-01

    A collective field accelerator which operates with a vacuum diode and utilizes a grooved cathode and a dielectric anode that operates with a relativistic electron beam with a .nu./.gamma. of .about. 1, and a plurality of dielectric lenses having an axial magnetic field thereabout to focus the collectively accelerated electrons and ions which are ejected from the anode. The anode and lenses operate as unoptimized r-f cavities which modulate and focus the beam.

  13. CEBAF accelerator achievements

    SciTech Connect

    Y.C. Chao, M. Drury, C. Hovater, A. Hutton, G.A. Krafft, M. Poelker, C. Reece, M. Tiefenback

    2011-06-01

    In the past decade, nuclear physics users of Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) have benefited from accelerator physics advances and machine improvements. As of early 2011, CEBAF operates routinely at 6 GeV, with a 12 GeV upgrade underway. This article reports highlights of CEBAF's scientific and technological evolution in the areas of cryomodule refurbishment, RF control, polarized source development, beam transport for parity experiments, magnets and hysteresis handling, beam breakup, and helium refrigerator operational optimization.

  14. LHCb GPU acceleration project

    NASA Astrophysics Data System (ADS)

    Badalov, A.; Cámpora, D.; Neufeld, N.; Vilasís-Cardona, X.

    2016-01-01

    The LHCb detector is due to be upgraded for processing high-luminosity collisions, which will increase data bandwidth to the event filter farm from 100 GB/s to 4 TB/s, encouraging us to look for new ways of accelerating Online reconstruction. The Coprocessor Manager is a new framework for integrating LHCb's existing computation pipelines with massively parallel algorithms running on GPUs and other accelerators. This paper describes the system and analyzes its performance.

  15. Accelerated Molecular Dynamics Simulations of Reactive Hydrocarbon Systems

    SciTech Connect

    Stuart, Steven J.

    2014-02-25

    The research activities in this project consisted of four different sub-projects. Three different accelerated dynamics techniques (parallel replica dynamics, hyperdynamics, and temperature-accelerated dynamics) were applied to the modeling of pyrolysis of hydrocarbons. In addition, parallel replica dynamics was applied to modeling of polymerization.

  16. Multimegawatt cyclotron autoresonance accelerator

    SciTech Connect

    Hirshfield, J.L.; LaPointe, M.A.; Ganguly, A.K.; Yoder, R.B.; Wang, C.

    1996-05-01

    Means are discussed for generation of high-quality multimegawatt gyrating electron beams using rf gyroresonant acceleration. TE{sub 111}-mode cylindrical cavities in a uniform axial magnetic field have been employed for beam acceleration since 1968; such beams have more recently been employed for generation of radiation at harmonics of the gyration frequency. Use of a TE{sub 11}-mode waveguide for acceleration, rather than a cavity, is discussed. It is shown that the applied magnetic field and group velocity axial tapers allow resonance to be maintained along a waveguide, but that this is impractical in a cavity. In consequence, a waveguide cyclotron autoresonance accelerator (CARA) can operate with near-100{percent} efficiency in power transfer from rf source to beam, while cavity accelerators will, in practice, have efficiency values limited to about 40{percent}. CARA experiments are described in which an injected beam of up to 25 A, 95 kV has had up to 7.2 MW of rf power added, with efficiencies of up to 96{percent}. Such levels of efficiency are higher than observed previously in any fast-wave interaction, and are competitive with efficiency values in industrial linear accelerators. Scaling arguments suggest that good quality gyrating megavolt beams with peak and average powers of 100 MW and 100 kW can be produced using an advanced CARA, with applications in the generation of high-power microwaves and for possible remediation of flue gas pollutants. {copyright} {ital 1996 American Institute of Physics.}

  17. Laser Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Malka, Victor

    The continuing development of powerful laser systems has permitted to extend the interaction of laser beams with matter far into the relativistic domain, and to demonstrate new approaches for producing energetic particle beams. The extremely large electric fields, with amplitudes exceeding the TV/m level, that are produced in plasma medium are of relevance particle acceleration. Since the value of this longitudinal electric field, 10,000 times larger than those produced in conventional radio-frequency cavities, plasma accelerators appear to be very promising for the development of compact accelerators. The incredible progresses in the understanding of laser plasma interaction physic, allows an excellent control of electron injection and acceleration. Thanks to these recent achievements, laser plasma accelerators deliver today high quality beams of energetic radiation and particles. These beams have a number of interesting properties such as shortness, brightness and spatial quality, and could lend themselves to applications in many fields, including medicine, radio-biology, chemistry, physics and material science,security (material inspection), and of course in accelerator science.

  18. Biomedical accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Freeman, Stewart P. H. T.; Vogel, John S.

    1995-05-01

    Ultrasensitive SIMS with accelerator based spectrometers has recently begun to be applied to biomedical problems. Certain very long-lived radioisotopes of very low natural abundances can be used to trace metabolism at environmental dose levels ( [greater-or-equal, slanted] z mol in mg samples). 14C in particular can be employed to label a myriad of compounds. Competing technologies typically require super environmental doses that can perturb the system under investigation, followed by uncertain extrapolation to the low dose regime. 41Ca and 26Al are also used as elemental tracers. Given the sensitivity of the accelerator method, care must be taken to avoid contamination of the mass spectrometer and the apparatus employed in prior sample handling including chemical separation. This infant field comprises the efforts of a dozen accelerator laboratories. The Center for Accelerator Mass Spectrometry has been particularly active. In addition to collaborating with groups further afield, we are researching the kinematics and binding of genotoxins in-house, and we support innovative uses of our capability in the disciplines of chemistry, pharmacology, nutrition and physiology within the University of California. The field can be expected to grow further given the numerous potential applications and the efforts of several groups and companies to integrate more the accelerator technology into biomedical research programs; the development of miniaturized accelerator systems and ion sources capable of interfacing to conventional HPLC and GMC, etc. apparatus for complementary chemical analysis is anticipated for biomedical laboratories.

  19. Accelerators for America's Future

    NASA Astrophysics Data System (ADS)

    Bai, Mei

    2016-03-01

    Particle accelerator, a powerful tool to energize beams of charged particles to a desired speed and energy, has been the working horse for investigating the fundamental structure of matter and fundermental laws of nature. Most known examples are the 2-mile long Stanford Linear Accelerator at SLAC, the high energy proton and anti-proton collider Tevatron at FermiLab, and Large Hadron Collider that is currently under operation at CERN. During the less than a century development of accelerator science and technology that led to a dazzling list of discoveries, particle accelerators have also found various applications beyond particle and nuclear physics research, and become an indispensible part of the economy. Today, one can find a particle accelerator at almost every corner of our lives, ranging from the x-ray machine at the airport security to radiation diagnostic and therapy in hospitals. This presentation will give a brief introduction of the applications of this powerful tool in fundermental research as well as in industry. Challenges in accelerator science and technology will also be briefly presented

  20. Accelerator shielding design for PFNA applications

    SciTech Connect

    Shayer, Z.; Clayton, J.E.; Gozani, T. )

    1993-01-01

    The Pulsed Fast Neutron Analysis (PFNA) method utilizes the capability of high-energy neutrons to penetrate deeply and stimulate the emission of characteristic gamma rays that can be detected and used to identify and image the emitting chemical elements. The PFNA method interrogates the object using a directional beam consisting of short bursts of fast neutrons from a pulsed deuteron accelerator, with the neutrons generated in a deuteron gas target. In order to study the performance of the PFNA system, a National Electrostatics Corporation (NEC) Pelletron accelerator was acquired and installed at the Science Applications International Corporation (SAIC) facility in Santa Clara, California. The NEC Pelletron accelerator produces 6- or 12-MHz pulses of up to 6-MeV deuterons with a beam current that will reach up to 100 [mu]A. There are several identifiable radiation sources during operation of the PFNA system: (1) neutron production target and deuteron beam stop; (2) neutrons and gamma rays from the interrogation area; (3) X rays generated inside the accelerator because of free electrons between the accelerator tube segments, which are at different potentials; and (4) neutrons and gamma rays generated by deuteron striking limiting apertures within the acceleration column.

  1. Particle Acceleration in Superluminal Strong Waves

    NASA Astrophysics Data System (ADS)

    Teraki, Yuto; Ito, Hirotaka; Nagataki, Shigehiro

    2015-06-01

    We calculate the electron acceleration in random superluminal strong waves (SLSWs) and radiation from them using numerical methods in the context of the termination shocks of pulsar wind nebulae. We pursue the orbit of electrons by solving the equation of motion in the analytically expressed electromagnetic turbulences. These consist of a primary SLS and isotropically distributed secondary electromagnetic waves. Under the dominance of the secondary waves, all electrons gain nearly equal energy. On the other hand, when the primary wave is dominant, selective acceleration occurs. The phase of the primary wave for electrons moving nearly along the wavevector changes very slowly compared with the oscillation of the wave, which is “phase-locked,” and such electrons are continuously accelerated. This acceleration by SLSWs may play a crucial role in pre-shock acceleration. In general, the radiation from the phase-locked population is different from the synchro-Compton radiation. However, when the amplitude of the secondary waves is not extremely weaker than that of the primary wave, the typical frequency can be estimated from synchro-Compton theory using the secondary waves. The primary wave does not contribute to the radiation because the SLSW accelerates electrons almost linearly. This radiation can be observed as a radio knot at the upstream of the termination shocks of the pulsar wind nebulae without counterparts in higher frequency ranges.

  2. Fermilab accelerator control system: Analog monitoring facilities

    SciTech Connect

    Seino, K.; Anderson, L.; Smedinghoff, J.

    1987-10-01

    Thousands of analog signals are monitored in different areas of the Fermilab accelerator complex. For general purposes, analog signals are sent over coaxial or twinaxial cables with varying lengths, collected at fan-in boxes and digitized with 12 bit multiplexed ADCs. For higher resolution requirements, analog signals are digitized at sources and are serially sent to the control system. This paper surveys ADC subsystems that are used with the accelerator control systems and discusses practical problems and solutions, and it describes how analog data are presented on the console system.

  3. Diffusive Shock Acceleration and Reconnection Acceleration Processes

    NASA Astrophysics Data System (ADS)

    Zank, G. P.; Hunana, P.; Mostafavi, P.; Le Roux, J. A.; Li, Gang; Webb, G. M.; Khabarova, O.; Cummings, A.; Stone, E.; Decker, R.

    2015-12-01

    Shock waves, as shown by simulations and observations, can generate high levels of downstream vortical turbulence, including magnetic islands. We consider a combination of diffusive shock acceleration (DSA) and downstream magnetic-island-reconnection-related processes as an energization mechanism for charged particles. Observations of electron and ion distributions downstream of interplanetary shocks and the heliospheric termination shock (HTS) are frequently inconsistent with the predictions of classical DSA. We utilize a recently developed transport theory for charged particles propagating diffusively in a turbulent region filled with contracting and reconnecting plasmoids and small-scale current sheets. Particle energization associated with the anti-reconnection electric field, a consequence of magnetic island merging, and magnetic island contraction, are considered. For the former only, we find that (i) the spectrum is a hard power law in particle speed, and (ii) the downstream solution is constant. For downstream plasmoid contraction only, (i) the accelerated spectrum is a hard power law in particle speed; (ii) the particle intensity for a given energy peaks downstream of the shock, and the distance to the peak location increases with increasing particle energy, and (iii) the particle intensity amplification for a particular particle energy, f(x,c/{c}0)/f(0,c/{c}0), is not 1, as predicted by DSA, but increases with increasing particle energy. The general solution combines both the reconnection-induced electric field and plasmoid contraction. The observed energetic particle intensity profile observed by Voyager 2 downstream of the HTS appears to support a particle acceleration mechanism that combines both DSA and magnetic-island-reconnection-related processes.

  4. Student Effort, Consistency, and Online Performance

    ERIC Educational Resources Information Center

    Patron, Hilde; Lopez, Salvador

    2011-01-01

    This paper examines how student effort, consistency, motivation, and marginal learning, influence student grades in an online course. We use data from eleven Microeconomics courses taught online for a total of 212 students. Our findings show that consistency, or less time variation, is a statistically significant explanatory variable, whereas…

  5. 40 CFR 55.12 - Consistency updates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Consistency updates. 55.12 Section 55.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) OUTER CONTINENTAL SHELF AIR REGULATIONS § 55.12 Consistency updates. (a) The Administrator will...

  6. 40 CFR 55.12 - Consistency updates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Consistency updates. 55.12 Section 55.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) OUTER CONTINENTAL SHELF AIR REGULATIONS § 55.12 Consistency updates. (a) The Administrator will update this part as necessary to maintain...

  7. 15 CFR 930.96 - Consistency review.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Consistency review. 930.96 Section 930... and Local Governments § 930.96 Consistency review. (a)(1) If the State agency does not object to the proposed activity, the Federal agency may grant the federal assistance to the applicant...

  8. 15 CFR 930.96 - Consistency review.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Consistency review. 930.96 Section 930... and Local Governments § 930.96 Consistency review. (a)(1) If the State agency does not object to the proposed activity, the Federal agency may grant the federal assistance to the applicant...

  9. 15 CFR 930.96 - Consistency review.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Consistency review. 930.96 Section 930... and Local Governments § 930.96 Consistency review. (a)(1) If the State agency does not object to the proposed activity, the Federal agency may grant the federal assistance to the applicant...

  10. 15 CFR 930.96 - Consistency review.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Consistency review. 930.96 Section 930... and Local Governments § 930.96 Consistency review. (a)(1) If the State agency does not object to the proposed activity, the Federal agency may grant the federal assistance to the applicant...

  11. 15 CFR 930.96 - Consistency review.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Consistency review. 930.96 Section 930.96 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT FEDERAL CONSISTENCY WITH APPROVED...

  12. Consistency and Enhancement Processes in Understanding Emotions

    ERIC Educational Resources Information Center

    Stets, Jan E.; Asencio, Emily K.

    2008-01-01

    Many theories in the sociology of emotions assume that emotions emerge from the cognitive consistency principle. Congruence among cognitions produces good feelings whereas incongruence produces bad feelings. A work situation is simulated in which managers give feedback to workers that is consistent or inconsistent with what the workers expect to…

  13. Ion Acceleration in Solar Flares

    NASA Technical Reports Server (NTRS)

    Miller, James A.; Weir, Sue B.

    1996-01-01

    Solar flares are among the most energetic and interesting phenomena in the Solar system, releasing up to 1032 ergs of energy on timescales of several tens of seconds to several tens of minutes. Much of this energy is in the form of suprathermal electrons and ions, which remain trapped at the Sun and produce a wide variety of radiations, as well as escape into interplanetary space, where they can be directly observed. The radiation from trapped particles consists in general of (1) continuum emission; (2) narrow gamma-ray nuclear deexcitation lines; and (3) high-energy neutrons observed in space or by ground-based neutron monitors. The particles that escape into space consist of both electrons and ions, which often have compositions quite different than that of the ambient solar atmosphere. Flares thus present many diagnostics of the particle acceleration mechanism(s), the identification of which is the ultimate goal of flare research. Moreover, flares in fact offer the only opportunity in astrophysics to study the simultaneous energization of both electrons and ions. Hopefully, an understanding of flares with their wealth of diagnostic data will lead to a better understanding of particle acceleration at other sites in the Universe. It is now generally accepted that flares are roughly divided into two classes: impulsive and gradual. Gradual events are large, occur high in the corona, have long-duration soft and hard X-rays and gamma rays, are electron poor, are associated with Type II radio emission and coronal mass ejections (CMEs), and produce energetic ions with coronal abundance ratios. Impulsive events are more compact, occur lower in the corona, produce short-duration radiation, and exhibit dramatic abundance enhancements in the energetic ions. Their He-3/He-4 ratio is - 1, which is a huge increase over the coronal value of about 5 x 10(exp -4), and they also posses smaller but still significant enhancements of Ne, Mg, Si, and Fe relative to He-4, C, N, and O

  14. Microstructural characterization of bainitic steel submitted to torsion testing and interrupted accelerated cooling

    SciTech Connect

    Cota, A.B.; Santos, D.B.

    2000-03-01

    HSLA low-carbon bainitic steel containing B was submitted to torsion tests to simulate controlled rolling, followed by interrupted accelerated cooling. Microstructural characteristics and the mechanisms for the refinement of structure were evaluated using light microscopy, scanning electron microscopy, transmission electron microscopy, and Vickers hardness testing. The final microstructure was found to contain complex mixture of granular bainite, small islands of MA constituent, bainitic ferrite, and polygonal ferrite. Increasing the cooling rate of decreasing the finish cooling temperature resulted in a decrease in the volume fraction and average size of the MA islands and the polygonal ferrite. A finish cooing temperature of 400 C produced a microstructure consisting of fine laths of bainitic ferrite with an interlath MA constituent. A quantitative relationship between the accelerated cooling variables and the ferrite grain size was developed.

  15. Stochastic inverse consistency in medical image registration.

    PubMed

    Yeung, Sai Kit; Shi, Pengcheng

    2005-01-01

    An essential goal in medical image registration is, the forward and reverse mapping matrices should be inverse to each other, i.e., inverse consistency. Conventional approaches enforce consistency in deterministic fashions, through incorporation of sub-objective cost function to impose source-destination symmetric property during the registration process. Assuming that the initial forward and reverse matching matrices have been computed and used as the inputs to our system, this paper presents a stochastic framework which yields perfect inverse consistency with the simultaneous considerations of the errors underneath the registration matrices and the imperfectness of the consistent constraint. An iterative generalized total least square (GTLS) strategy has been developed such that the inverse consistency is optimally imposed. PMID:16685959

  16. Managing consistency in collaborative design environments

    NASA Astrophysics Data System (ADS)

    Miao, Chunyan; Yang, Zhonghua; Goh, Angela; Sun, Chengzheng; Sattar, Abdul

    1999-08-01

    In today's global economy, there is a significant paradigm shift to collaborative engineering design environments. One of key issues in the collaborative setting is the consistency model, which governs how to coordinate the activities of collaborators to ensure that they do not make inconsistent changes or updates to the shared objects. In this paper, we present a new consistency model which requires that all update operations will be executed in the casual order (causality) and all participants have the same view on the operations on the shared objects (view synchrony). A simple multicast-based protocol to implement the consistency model is presented. By employing vector time and token mechanisms, the protocol brings the shared objects from one consistent state to another, thus providing collaborators with a consistent view of the shared objects. A CORBA-based on-going prototyping implementation is outlined. Some of the related work are also discussed.

  17. High-performance speech recognition using consistency modeling

    NASA Astrophysics Data System (ADS)

    Digilakis, Vassilios; Monaco, Peter; Murveit, Hy; Weintraub, Mitchel

    1994-03-01

    The goal of this project conducted by SRI International (SRI) is to develop consistency modeling technology. Consistency modeling aims to reduce the number of improper independence assumptions used in traditional speech-recognition algorithms so that the resulting speech-recognition hypotheses are more self-consistent and, therefore, more accurate. Consistency is achieved by conditioning HMM output distributions on state and observations histories, P(x/s,H). The technical objective of the project is to find the proper form of the probability distribution, P; the proper history vector, H; the proper feature vector, x; and to develop the infrastructure (e.g. efficient estimation and search techniques) so that consistency modeling can be effectively used. During the first year of this effort, SRI focused on developing the appropriate base technologies for consistency modeling. We developed genonic hidden Markov model (HMM) technology, our choice for P above, and Progressive Search technology for HMM systems which allows us to develop and use complex HMM formulations in an efficient manner. Papers describing these two techniques are included in the appendix of this report and are briefly summarized below. This report also describes other accomplishments of Year 1 including the initial exploitation of discrete and continuous consistency modeling and the development of a scheme for efficiently computing Gaussian probabilities.

  18. Acceleration of positrons in supernova shocks

    NASA Technical Reports Server (NTRS)

    Ellison, Donald C.

    1992-01-01

    During this project we investigated the acceleration of leptons (electrons and positrons) in collisionless shock waves. In particular, we were interested in how leptons are accelerated in the blast waves existing in the remnants of supernova explosions. Supernova remnants (SNRs) have long been considered as the most likely source of galactic cosmic rays but no definite connection between SNRs and the cosmic rays seen at earth can be made. Only by understanding lepton acceleration in shocks can the rich SNR data base be properly used to understand cosmic ray origins. Our project was directed at the neglected aspects of lepton acceleration. We showed that the efficiency of lepton acceleration depended critically on the lepton injection energy. We showed that, even when infection effects are not important, that proton and lepton distribution functions produced by shocks are quite different in the critical energy range for producing the observed synchrotron emission. We also showed that transrelativistic effects produced proton spectra that were not in agreement with standard results from radio observations, but that the lepton spectra were, in fact, consistent with observations. We performed simulations of relativistic shocks (shocks where the flow speed is a sizable fraction of the speed of light) and discovered some interesting effects. We first demonstrated the power of the Monte Carlo technique by determining the shock jump conditions in relativistic shocks. We then proceeded to determine how relativistic shocks accelerate particles. We found that nonlinear relativistic shocks treat protons and leptons even more differently than nonrelativistic shocks. The transrelativistic effects on the shock structure from the heavy ion component reduces the lepton acceleration to a tiny fraction of the ion acceleration. This effect is dramatic even if high energy leptons (many times thermal energy) are injected, and was totally unexpected. Our results have important

  19. Arc-driven rail accelerator research

    NASA Technical Reports Server (NTRS)

    Ray, Pradosh K.

    1987-01-01

    Arc-driven rail accelerator research is analyzed by considering wall ablation and viscous drag in the plasma. Plasma characteristics are evaluated through a simple fluid-mechanical analysis considering only wall ablation. By equating the energy dissipated in the plasma with the radiation heat loss, the average properties of the plasma are determined as a function of time and rate of ablation. Locations of two simultaneously accelerating arcs were determined by optical and magnetic probes and fron streak camera photographs. All three measurements provide consistent results.

  20. Industrialization of Superconducting RF Accelerator Technology

    NASA Astrophysics Data System (ADS)

    Peiniger, Michael; Pekeler, Michael; Vogel, Hanspeter

    2012-01-01

    Superconducting RF (SRF) accelerator technology has basically existed for 50 years. It took about 20 years to conduct basic R&D and prototyping at universities and international institutes before the first superconducting accelerators were built, with industry supplying complete accelerator cavities. In parallel, the design of large scale accelerators using SRF was done worldwide. In order to build those accelerators, industry has been involved for 30 years in building the required cavities and/or accelerator modules in time and budget. To enable industry to supply these high tech components, technology transfer was made from the laboratories in the following three regions: the Americas, Asia and Europe. As will be shown, the manufacture of the SRF cavities is normally accomplished in industry whereas the cavity testing and module assembly are not performed in industry in most cases, yet. The story of industrialization is so far a story of customized projects. Therefore a real SRF accelerator product is not yet available in this market. License agreements and technology transfer between leading SRF laboratories and industry is a powerful tool for enabling industry to manufacture SRF components or turnkey superconducting accelerator modules for other laboratories and users with few or no capabilities in SRF technology. Despite all this, the SRF accelerator market today is still a small market. The manufacture and preparation of the components require a range of specialized knowledge, as well as complex and expensive manufacturing installations like for high precision machining, electron beam welding, chemical surface preparation and class ISO4 clean room assembly. Today, the involved industry in the US and Europe comprises medium-sized companies. In Japan, some big enterprises are involved. So far, roughly 2500 SRF cavities have been built by or ordered from industry worldwide. Another substantial step might come from the International Linear Collider (ILC) project

  1. Pulsed electron accelerator for radiation technologies in the enviromental applications

    NASA Astrophysics Data System (ADS)

    Korenev, Sergey

    1997-05-01

    The project of pulsed electron accelerator for radiation technologies in the environmental applications is considered. An accelerator consists of high voltage generator with vacuum insulation and vacuum diode with plasma cathode on the basis discharge on the surface of dielectric of large dimensions. The main parameters of electron accelerators are following: kinetic energy 0.2 - 2.0 MeV, electron beam current 1 - 30 kA and pulse duration 1- 5 microseconds. The main applications of accelerator for decomposition of wastewaters are considered.

  2. Simulation of particle acceleration in the PLASMONX project

    NASA Astrophysics Data System (ADS)

    Benedetti, Carlo

    2010-02-01

    In this paper I will present some numerical studies and parameter scans performed with the electromagnetic, rela-tivistic, fully-self consistent particle-in-cell (PIC) code ALaDyn (Acceleration by LAser and DYNamics of charged particles), concerning electron acceleration via plasma waves in the framework of the INFN-PLASMONX (PLASma acceleration and MONochromatic X-ray production) project. In particular I will focus on the modelling of the SITE (Self Injection Test Experiment) which will be a relevant part of the commissioning of the FLAME laser. Some issues related to the quality of the accelerated bunch will be discussed.

  3. Advanced accelerator theory development

    SciTech Connect

    Sampayan, S.E.; Houck, T.L.; Poole, B.; Tishchenko, N.; Vitello, P.A.; Wang, I.

    1998-02-09

    A new accelerator technology, the dielectric wall accelerator (DWA), is potentially an ultra compact accelerator/pulsed power driver. This new accelerator relies on three new components: the ultra-high gradient insulator, the asymmetric Blumlein and low jitter switches. In this report, we focused our attention on the first two components of the DWA system the insulators and the asymmetric Blumlein. First, we sought to develop the necessary design tools to model and scale the behavior of the high gradient insulator. To perform this task we concentrated on modeling the discharge processes (i.e., initiation and creation of the surface discharge). In addition, because these high gradient structures exhibit favorable microwave properties in certain accelerator configurations, we performed experiments and calculations to determine the relevant electromagnetic properties. Second, we performed circuit modeling to understand energy coupling to dynamic loads by the asymmetric Blumlein. Further, we have experimentally observed a non-linear coupling effect in certain asymmetric Blumlein configurations. That is, as these structures are stacked into a complete module, the output voltage does not sum linearly and a lower than expected output voltage results. Although we solved this effect experimentally, we performed calculations to understand this effect more fully to allow better optimization of this DWA pulse-forming line system.

  4. High energy plasma accelerators

    SciTech Connect

    Tajima, T.

    1985-05-01

    Colinear intense laser beams ..omega../sub 0/, kappa/sub 0/ and ..omega../sub 1/, kappa/sub 1/ shone on a plasma with frequency separation equal to the electron plasma frequency ..omega../sub pe/ are capable of creating a coherent large longitudinal electric field E/sub L/ = mc ..omega../sub pe//e of the order of 1GeV/cm for a plasma density of 10/sup 18/ cm/sup -3/ through the laser beat excitation of plasma oscillations. Accompanying favorable and deleterious physical effects using this process for a high energy beat-wave accelerator are discussed: the longitudinal dephasing, pump depletion, the transverse laser diffraction, plasma turbulence effects, self-steepening, self-focusing, etc. The basic equation, the driven nonlinear Schroedinger equation, is derived to describe this system. Advanced accelerator concepts to overcome some of these problems are proposed, including the plasma fiber accelerator of various variations. An advanced laser architecture suitable for the beat-wave accelerator is suggested. Accelerator physics issues such as the luminosity are discussed. Applications of the present process to the current drive in a plasma and to the excitation of collective oscillations within nuclei are also discussed.

  5. Acoustic particle acceleration sensors

    SciTech Connect

    Franklin, J.B.; Barry, P.J.

    1996-04-01

    A crossed dipole array provides a directional receiving capability in a relatively small sensor package and is therefore very attractive for many applications in acoustics. Particle velocity measurements on two axes perpendicular to each other are required to provide the dipole signals. These can be obtained directly using particle velocity sensors or via simple transfer functions using acceleration and displacement sensors. Also, the derivative of the acoustic pressure with respect to space provides a signal proportional to the particle acceleration and gives rise to the pressure gradient sensor. Each of these sensors has strengths and drawbacks depending on the frequency regime of interest, the noise background, and whether a point or a line configuration of dipole sensors is desired. In this paper, the performance of acceleration sensors is addressed using a sensor concept developed at DREA. These sensors exploit bending stresses in a cantilever beam of piezoelectric material to obtain wide bandwidth and high sensitivity. Models which predict the acceleration sensitivity, pressure sensitivity, and natural frequency for this type of sensor are described. Experimental results obtained using several different versions of these sensors are presented and compared with theory. The predicted performance of acceleration sensors are compared with that of pressure gradient arrays and particle velocity sensors. {copyright} {ital 1996 American Institute of Physics.}

  6. Electrostatic Plasma Accelerator (EPA)

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Aston, Graeme

    1989-01-01

    The Electrostatic Plasma Accelerator (EPA) is a thruster concept which promises specific impulse levels between low power arcjets and those of the ion engine while retaining the relative simplicity of the arcjet. The EPA thruster produces thrust through the electrostatic acceleration of a moderately dense plasma. No accelerating electrodes are used and the specific impulse is a direct function of the applied discharge voltage and the propellant atomic mass. The goal of the present program is to demonstrate feasibility of the EPA thruster concept through experimental and theoretical investigations of the EPA acceleration mechanism and discharge chamber performance. Experimental investigations will include operating the test bed ion (TBI) engine as an EPA thruster and parametrically varying the thruster geometry and operating conditions to quantify the electrostatic plasma acceleration effect. The theoretical investigations will include the development of a discharge chamber model which describes the relationships between the engine size, plasma properties, and overall performance. For the EPA thruster to be a viable propulsion concept, overall thruster efficiencies approaching 30% with specific impulses approaching 1000 s must be achieved.

  7. Radiation from accelerated particles in relativistic jets with shocks and shear-flow

    NASA Astrophysics Data System (ADS)

    Nishikawa, Ken-Ichi; Hardee, Phil; Dutan, Ioana; Niemiec, Jacek; Medvedev, Mikhail; Meli, Athina; Mizuno, Yosuke; Nordlund, Aake; Trier Frederiksen, Jacob; Sol, Helene; Zhang, Bing; Pohl, Martin; Hartmann, Dieter

    2014-08-01

    We investigated particle acceleration and shock structure associated with an unmagnetized relativistic jet propagating into an unmagnetized plasma. Strong magnetic fields generated in the trailing shock contribute to the electron’s transverse deflection and acceleration. Kinetic Kelvin-Helmholtz instability (KKHI) is also responsible to create strong DC and AC magnetic fields. The velocity shears in core-sheath jets create strong magnetic field perpendicular to the jet. We examine how the Lorentz factors of jets affect the growth rates of KKHI. We have calculated, self-consistently, the radiation from electrons accelerated in these turbulent magnetic fields in the shocks. We found that the synthetic spectra depend on the bulk Lorentz factor of the jet, its temperature and strength of the generated magnetic fields. We will investigate synthetic spectra from accelerated electrons in strong magnetic fields generated by KKHI. The calculated properties of the emerging radiation provide our understanding of the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets in general, and supernova remnants.

  8. Stochastic Particle Acceleration in Impulsive Solar Flares

    NASA Technical Reports Server (NTRS)

    Miller, James A.

    2001-01-01

    The acceleration of a huge number of electrons and ions to relativistic energies over timescales ranging from several seconds to several tens of seconds is the fundamental problem in high-energy solar physics. The cascading turbulence model we have developed has been shown previously (e.g., Miller 2000; Miller & Roberts 1995; Miner, LaRosa, & Moore 1996) to account for all the bulk features (such as acceleration timescales, fluxes, total number of energetic particles, and maximum energies) of electron and proton acceleration in impulsive solar flares. While the simulation of this acceleration process is involved, the essential idea of the model is quite simple, and consists of just a few parts: 1. During the primary flare energy release phase, we assume that low-amplitude MHD Alfven and fast mode waves are excited at long wavelengths, say comparable to the size of the event (although the results are actually insensitive to this initial wavelength). While an assumption, this appears reasonable in light of the likely highly turbulent nature of the flare. 2. These waves then cascade in a Kolmogorov-like fashion to smaller wavelengths (e.g., Verma et al. 1996), forming a power-law spectral density in wavenumber space through the inertial range. 3. When the mean wavenumber of the fast mode waves has increased sufficiently, the transit-time acceleration rate (Miller 1997) for superAlfvenic electrons can overcome Coulomb energy losses, and these electrons are accelerated out of the thermal distribution and to relativistic energies (Miller et al. 1996). As the Alfven waves cascade to higher wavenumbers, they can cyclotron resonate with progressively lower energy protons. Eventually, they will resonate with protons in the tail of the thermal distribution, which will then be accelerated to relativistic energies as well (Miller & Roberts 1995). Hence, both ions and electrons are stochastically accelerated, albeit by different mechanisms and different waves. 4. When the

  9. Plasma-based accelerator structures

    SciTech Connect

    Schroeder, Carl B.

    1999-12-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas.

  10. Generalized radially self-accelerating helicon beams.

    PubMed

    Vetter, Christian; Eichelkraut, Toni; Ornigotti, Marco; Szameit, Alexander

    2014-10-31

    We report, in theory and experiment, on a new class of optical beams that are radially self-accelerating and nondiffracting. These beams continuously evolve on spiraling trajectories while maintaining their amplitude and phase distribution in their rotating rest frame. We provide a detailed insight into the theoretical origin and characteristics of radial self-acceleration and prove our findings experimentally. As radially self-accelerating beams are nonparaxial and a solution to the full scalar Helmholtz equation, they can be implemented in many linear wave systems beyond optics, from acoustic and elastic waves to surface waves in fluids and soft matter. Our work generalized the study of classical helicon beams to a complete set of solutions for rotating complex fields. PMID:25396370

  11. On the initial state and consistency relations

    SciTech Connect

    Berezhiani, Lasha; Khoury, Justin E-mail: jkhoury@sas.upenn.edu

    2014-09-01

    We study the effect of the initial state on the consistency conditions for adiabatic perturbations. In order to be consistent with the constraints of General Relativity, the initial state must be diffeomorphism invariant. As a result, we show that initial wavefunctional/density matrix has to satisfy a Slavnov-Taylor identity similar to that of the action. We then investigate the precise ways in which modified initial states can lead to violations of the consistency relations. We find two independent sources of violations: i) the state can include initial non-Gaussianities; ii) even if the initial state is Gaussian, such as a Bogoliubov state, the modified 2-point function can modify the q-vector → 0 analyticity properties of the vertex functional and result in violations of the consistency relations.

  12. Ensuring the Consistency of Silicide Coatings

    NASA Technical Reports Server (NTRS)

    Ramani, V.; Lampson, F. K.

    1982-01-01

    Diagram specifies optimum fusing time for given thicknesses of refractory metal-silicide coatings on columbium C-103 substrates. Adherence to indicated fusion times ensures consistent coatings and avoids underdiffusion and overdiffusion. Accuracy of diagram has been confirmed by tests.

  13. Consistent stabilizability of switched Boolean networks.

    PubMed

    Li, Haitao; Wang, Yuzhen

    2013-10-01

    This paper investigates the consistent stabilizability of switched Boolean networks (SBNs) by using the semi-tensor product method, and presents a number of new results. First, an algebraic expression of SBNs is obtained by the semi-tensor product, based on which the consistent stabilizability is then studied for SBNs and some necessary and sufficient conditions are presented for the design of free-form and state-feedback switching signals, respectively. Finally, the consistent stabilizability of SBNs with state constraints is considered and some necessary and sufficient conditions are proposed. The study of illustrative examples shows that the new results obtained in this paper are very effective in designing switching signals for the consistent stabilizability of SBNs. PMID:23787170

  14. Consistency relations for non-Gaussianity

    NASA Astrophysics Data System (ADS)

    Li, Miao; Wang, Yi

    2008-09-01

    We investigate consistency relations for non-Gaussianity. We provide a model-independent dynamical proof for the consistency relation for three-point correlation functions from the Hamiltonian and field redefinition. This relation can be applied to single-field inflation, multi-field inflation and the curvaton scenario. This relation can also be generalized to n-point correlation functions up to arbitrary order in perturbation theory and with arbitrary number of loops.

  15. Issues regarding acceleration in crystals

    SciTech Connect

    Chen, P.; Cline, D.B.; Gabella, W.E.

    1992-12-01

    Both self-acceleration and laser-acoustic acceleration in crystals are considered. The conduction electrons in the crystal are treated as a plasma and are the medium through which the acceleration takes place. Self-acceleration is the possible acceleration of part of a bunch due to plasma oscillations driven by the leading part. Laser- acoustic acceleration uses a laser in quasi-resonance with an acoustic wave to pump up the plasma oscillation to accelerate a beam. Self-driven schemes though experimentally simple seem problematic because single bunch densities must be large.

  16. Laser acceleration with open waveguides

    SciTech Connect

    Xie, Ming

    1999-03-01

    A unified framework based on solid-state open waveguides is developed to overcome all three major limitations on acceleration distance and hence on the feasibility of two classes of laser acceleration. The three limitations are due to laser diffraction, acceleration phase slippage, and damage of waveguide structure by high power laser. The two classes of laser acceleration are direct-field acceleration and ponderomotive-driven acceleration. Thus the solutions provided here encompass all mainstream approaches for laser acceleration, either in vacuum, gases or plasmas.

  17. Uniform acceleration in general relativity

    NASA Astrophysics Data System (ADS)

    Friedman, Yaakov; Scarr, Tzvi

    2015-10-01

    We extend de la Fuente and Romero's (Gen Relativ Gravit 47:33, 2015) defining equation for uniform acceleration in a general curved spacetime from linear acceleration to the full Lorentz covariant uniform acceleration. In a flat spacetime background, we have explicit solutions. We use generalized Fermi-Walker transport to parallel transport the Frenet basis along the trajectory. In flat spacetime, we obtain velocity and acceleration transformations from a uniformly accelerated system to an inertial system. We obtain the time dilation between accelerated clocks. We apply our acceleration transformations to the motion of a charged particle in a constant electromagnetic field and recover the Lorentz-Abraham-Dirac equation.

  18. Accelerating the culture change!

    PubMed

    Klunk, S W; Panetta, J; Wooten, J

    1996-11-01

    Exide Electronics, a major supplier of uninterruptible power system equipment, embarked on a journey of changing a culture to improve quality, enhance customer responsiveness, and reduce costs. This case study examines the evolution of change over a period of seven years, with particular emphasis on the most recent years, 1992 through 1995. The article focuses on the Raleigh plant operations and describes how each succeeding year built on the successes and fixed the shortcomings of the prior years to accelerate the culture change, including corrective action and continuous improvement processes, organizational structures, expectations, goals, achievements, and pitfalls. The real challenge to changing the culture was structuring a dynamic approach to accelerate change! The presentation also examines how the evolutionary process itself can be created and accelerated through ongoing communication, regular feedback of progress and goals, constant evaluation and direction of the process, and measuring and paying for performance. PMID:10162360

  19. Acceleration radioisotope production simulations

    SciTech Connect

    Waters, L.S.; Wilson, W.B.

    1996-12-31

    We have identified 96 radionuclides now being used or under consideration for use in medical applications. Previously, we calculated the production of {sup 99}Mo from enriched and depleted uranium targets at the 800-MeV energy used in the LAMPF accelerator at Los Alamos. We now consider the production of isotopes using lower energy beams, which may become available as a result of new high-intensity spallation target accelerators now being planned. The production of four radionuclides ({sup 7}Be, {sup 67}Cu, {sup 99}Mo, and {sup 195m}Pt) in a simplified proton accelerator target design is being examined. The LAHET, MCNP, and CINDER90 codes were used to model the target, transport a beam of protons and secondary produced particles through the system, and compute the nuclide production from spallation and low-energy neutron interactions. Beam energies of 200 and 400 MeV were used, and several targets were considered for each nuclide.

  20. Cosmic Plasma Wakefield Acceleration

    NASA Astrophysics Data System (ADS)

    Chen, Pisin; Tajima, Toshiki; Takahashi, Yoshiyuki

    2002-10-01

    A cosmic acceleration mechanism is introduced which is based on the wakefields excited by the Alfven shocks in a relativistically flowing plasma. We show that there exists a threshold condition for transparency below which the accelerating particle is collision-free and suffers little energy loss in the plasma medium. The stochastic encounters of the random accelerating-decelerating phases results in a power-law energy spectrum: f([epsilon]) [is proportional to] 1/[epsilon]2. As an example, we discuss the possible production of super-GZK ultra high energy cosmic rays (UHECR) in the atmosphere of gamma ray bursts. The estimated event rate in our model agrees with that from UHECR observations. [copyright] 2002 American Institute of Physics

  1. Microelectromechanical acceleration-sensing apparatus

    DOEpatents

    Lee, Robb M.; Shul, Randy J.; Polosky, Marc A.; Hoke, Darren A.; Vernon, George E.

    2006-12-12

    An acceleration-sensing apparatus is disclosed which includes a moveable shuttle (i.e. a suspended mass) and a latch for capturing and holding the shuttle when an acceleration event is sensed above a predetermined threshold level. The acceleration-sensing apparatus provides a switch closure upon sensing the acceleration event and remains latched in place thereafter. Examples of the acceleration-sensing apparatus are provided which are responsive to an acceleration component in a single direction (i.e. a single-sided device) or to two oppositely-directed acceleration components (i.e. a dual-sided device). A two-stage acceleration-sensing apparatus is also disclosed which can sense two acceleration events separated in time. The acceleration-sensing apparatus of the present invention has applications, for example, in an automotive airbag deployment system.

  2. Studies of accelerated compact toruses

    SciTech Connect

    Hartman, C.W.; Eddleman, J.; Hammer, J.H.

    1983-01-04

    In an earlier publication we considered acceleration of plasma rings (Compact Torus). Several possible accelerator configurations were suggested and the possibility of focusing the accelerated rings was discussed. In this paper we consider one scheme, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focusing) during acceleration. Because the allowable acceleration force, F/sub a/ = kappaU/sub m//R where (kappa < 1), increases as R/sup -2/, the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case, however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency.

  3. A seismologically consistent expression for the total area and volume of earthquake-triggered landsliding

    NASA Astrophysics Data System (ADS)

    Marc, Odin; Hovius, Niels; Meunier, Patrick; Gorum, Tolga; Uchida, Taro

    2016-04-01

    We present a new, seismologically consistent expression for the total area and volume of populations of earthquake-triggered landslides. This model builds on a set of scaling relationships between key parameters, such as landslide spatial density, seismic ground acceleration, fault length, earthquake source depth, and seismic moment. To assess the model we have assembled and normalized a catalog of landslide inventories for 40 shallow, continental earthquakes. Low landscape steepness causes systematic overprediction of the total area and volume of landslides. When this effect is accounted for, the model predicts the total landslide volume of 63% of 40 cases to within a factor 2 of the volume estimated from observations (R2=0.76). The prediction of total landslide area is also sensitive to the landscape steepness, but less so than the total volume, and it appears to be sensitive to controls on the landslide size-frequency distribution, and possibly the shaking duration. Some outliers are likely associated with exceptionally strong rock mass in the epicentral area, while others may be related to seismic source complexities ignored by the model. However, the close match between prediction and estimate for about two thirds of cases in our database suggests that rock mass strength is similar in many cases and that our simple seismic model is often adequate, despite the variety of lithologies and tectonic settings covered. This makes our expression suitable for integration into landscape evolution models and application to the anticipation or rapid assessment of secondary hazards associated with earthquakes.

  4. Diffusive Shock Acceleration

    NASA Astrophysics Data System (ADS)

    Baring, Matthew

    2003-04-01

    The process of diffusive acceleration of charged particles in shocked plasmas is widely invoked in astrophysics to account for the ubiquitous presence of signatures of non-thermal relativistic electrons and ions in the universe. This statistical energization mechanism, manifested in turbulent media, was first posited by Enrico Fermi in 1949 to explain the observed cosmic ray population, which exhibits an almost power-law distribution in rigidity. The absence of a momentum scale is a key characteristic of diffusive shock acceleration, and astrophysical systems generally only impose scales at the injection (low energy) and loss (high energy) ends of the particle spectrum. The existence of structure in the cosmic ray spectrum (the "knee") at around 3000 TeV has promoted contentions that there are at least two origins for cosmic rays, a galactic one supplying those up to the knee, and perhaps an extragalactic one that can explain even the ultra-high energy cosmic rays (UHECRs) seen at 1-300 EeV. Accounting for the UHECRs with familiar astrophysical sites of acceleration has historically proven difficult due to the need to assume high magnetic fields in order to reduce the shortest diffusive acceleration timescale, the ion gyroperiod, to meaningful values. Yet active galaxies and gamma-ray bursts remain strong and interesting candidate sources for UHECRs, turning the theoretical focus to relativistic shocks. This review summarizes properties of diffusive shock acceleration that are salient to the issue of UHECR generation. These include spectral indices, anisotropies, acceleration efficencies and timescales, as functions of the shock speed and mean field orientation, and also the degree of field turbulence. Astrophysical sites for UHECR production are also critiqued.

  5. heavy ion acceleration at shocks

    NASA Astrophysics Data System (ADS)

    Shevchenko, V. I.; Galinsky, V.

    2009-12-01

    The theoretical study of alpha particle acceleration at a quasi-parallel shock due to interaction with Alfven waves self-consistently excited in both upstream and downstream regions was conducted using a scale-separation model [1]. The model uses conservation laws and resonance conditions to find where waves will be generated or dumped and hence particles will be pitch--angle scattered as well as the change of the wave energy due to instability or damping. It includes in consideration the total distribution function (the bulk plasma and high energy tail), so no any assumptions (e.g. seed populations, or some ad-hoc escape rate of accelerated particles) are required. In previous studies heavy ions were treated as perfect test particles, they only experienced the Alfven turbulence excited by protons and didn’t contribute to turbulence generation. In contrast to this approach, we consider the ion scattering on hydromagnetic turbulence generated by both protons and ions themselves. It is important for alpha particles with their relatively large mass-loading parameter that defines efficiency of the wave excitation by alpha particles. The energy spectra of alpha particles is found and compared with those obtained in test particle approximation. [1] Galinsky, V.L., and V.I. Shevchenko, Astrophys. J., 669, L109, 2007.

  6. Interfacing to accelerator instrumentation

    SciTech Connect

    Shea, T.J.

    1995-12-31

    As the sensory system for an accelerator, the beam instrumentation provides a tremendous amount of diagnostic information. Access to this information can vary from periodic spot checks by operators to high bandwidth data acquisition during studies. In this paper, example applications will illustrate the requirements on interfaces between the control system and the instrumentation hardware. A survey of the major accelerator facilities will identify the most popular interface standards. The impact of developments such as isochronous protocols and embedded digital signal processing will also be discussed.

  7. HIGH GRADIENT INDUCTION ACCELERATOR

    SciTech Connect

    Caporaso, G J; Sampayan, S; Chen, Y; Blackfield, D; Harris, J; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Nunnally, W; Paul, A; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

    2007-06-21

    A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is stimulated by the desire for compact flash x-ray radiography sources. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be described. Progress in applying this technology to several applications will be reviewed.

  8. Spallator - accelerator breeder

    SciTech Connect

    Steinberg, M.

    1985-01-01

    The concept involves the use of spallation neutrons produced by interaction of a high energy proton (1 to 2 GeV) from a linear accelerator (LINAC) with a heavy metal target (uranium). The principal spallator concept is based on generating fissile fuel for use in LWR nuclear power plants. The spallator functions in conjunction with a reprocessing plant to regenerate and produce the Pu-239 or U-233 for fabrication into fresh LWR reactor fuel elements. Advances in proton accelerator technology has provided a solid base for predicting performance and optimizing the design of a reliable, continuous wave, high-current LINAC required by a fissile fuel production machine.

  9. 'Light Sail' Acceleration Reexamined

    SciTech Connect

    Macchi, Andrea; Veghini, Silvia; Pegoraro, Francesco

    2009-08-21

    The dynamics of the acceleration of ultrathin foil targets by the radiation pressure of superintense, circularly polarized laser pulses is investigated by analytical modeling and particle-in-cell simulations. By addressing self-induced transparency and charge separation effects, it is shown that for 'optimal' values of the foil thickness only a thin layer at the rear side is accelerated by radiation pressure. The simple 'light sail' model gives a good estimate of the energy per nucleon, but overestimates the conversion efficiency of laser energy into monoenergetic ions.

  10. Quality and Consistency of the NASA Ocean Color Data Record

    NASA Technical Reports Server (NTRS)

    Franz, Bryan A.

    2012-01-01

    The NASA Ocean Biology Processing Group (OBPG) recently reprocessed the multimission ocean color time-series from SeaWiFS, MODIS-Aqua, and MODIS-Terra using common algorithms and improved instrument calibration knowledge. Here we present an analysis of the quality and consistency of the resulting ocean color retrievals, including spectral water-leaving reflectance, chlorophyll a concentration, and diffuse attenuation. Statistical analysis of satellite retrievals relative to in situ measurements will be presented for each sensor, as well as an assessment of consistency in the global time-series for the overlapping periods of the missions. Results will show that the satellite retrievals are in good agreement with in situ measurements, and that the sensor ocean color data records are highly consistent over the common mission lifespan for the global deep oceans, but with degraded agreement in higher productivity, higher complexity coastal regions.

  11. Survey of Electronic Safety Systems in Accelerator Applications

    NASA Astrophysics Data System (ADS)

    Mahoney, K.

    1997-05-01

    This paper presents the preliminary results and analysis of a comprehensive survey of the implementation of accelerator safety interlock systems at over 20 international labs. At the present time there is not a self consistent means to evaluate both the experience and level of protection provided by electronic safety interlock systems. This research is intended to analyze the strengths and weaknesses of several different types of interlock system implementation methodologies. Research, medical, and industrial accelerators are compared. The CEBAF accelerator at Thomas Jefferson National Accelerator Facility (Jefferson Lab) was one of the first large particle accelerators to implement a safety interlock system using programmable logic controllers. Since that time all of the major new U.S. accelerator construction projects plan to use some form of programmable electronics as part of a safety interlock system in some capacity. To the author's knowledge such a compilation has not been presented before.

  12. Gradient Optimization for SC CW Accelerators

    SciTech Connect

    Schneider, William; Kneisel, Peter; Rode, Claus

    2003-05-01

    The proposed rare isotope accelerator (RIA) design consists of a normally conducting radio frequency quadruple (RFQ) section, a superconducting (SC) drift tube cavity section, a SC elliptical multi-cell cavity section and two charge strippers with associated charge state selection and beam matching optics. The SC elliptical section uses two or three multi-cell beta cavity types installed into cryomodules to span the energy region of about 84.5 MeV/nucleon up to 400 MeV/nucleon. This paper focuses on the gradient optimization of these SC elliptical cavities that provide a significant portion of the total acceleration to the beam. The choice of gradient coupled with the cavity quality factor has a strong affect on the overall cost of the accelerator. The paper describes the optimization of the capital and operating cost associated with the RIA elliptical cavity cryomodules.

  13. Preliminary results on open accelerating structures

    SciTech Connect

    Palmer, R.B.; Giordano, S.

    1985-01-07

    In this paper we consider periodic structures consisting of rows of spherical conductors. In a plasma linac, these spherical conductors would be formed from liquid droplets on whose surfaces a plasma would be formed. For this paper, the field configurations have been investigated using copper spheres approximately 11 cm diameter and microwave radiation of approximately 30 cm wavelength. No suitable accelerating mode was found for relativistic particles using a single row of spheres, but with two parallel rows of spheres both accelerating and focusing modes were found. In Section II we re-examine the accelerating modes over a grating surface, including a grating of parallel conducting rods. In Section III we discuss the coupling of these structures to incoming radiation. 3 refs., 6 figs.

  14. Enhancing proton acceleration by using composite targets

    SciTech Connect

    Bulanov, S. S.; Esarey, E.; Schroeder, C. B.; Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Pegoraro, F.; Leemans, W. P.

    2015-07-10

    Efficient laser ion acceleration requires high laser intensities, which can only be obtained by tightly focusing laser radiation. In the radiation pressure acceleration regime, where the tightly focused laser driver leads to the appearance of the fundamental limit for the maximum attainable ion energy, this limit corresponds to the laser pulse group velocity as well as to another limit connected with the transverse expansion of the accelerated foil and consequent onset of the foil transparency. These limits can be relaxed by using composite targets, consisting of a thin foil followed by a near critical density slab. Such targets provide guiding of a laser pulse inside a self-generated channel and background electrons, being snowplowed by the pulse, compensate for the transverse expansion. The use of composite targets results in a significant increase in maximum ion energy, compared to a single foil target case.

  15. Probing gravitation, dark energy, and acceleration

    SciTech Connect

    Linder, Eric V.

    2004-02-20

    The acceleration of the expansion of the universe arises from unknown physical processes involving either new fields in high energy physics or modifications of gravitation theory. It is crucial for our understanding to characterize the properties of the dark energy or gravity through cosmological observations and compare and distinguish between them. In fact, close consistencies exist between a dark energy equation of state function w(z) and changes to the framework of the Friedmann cosmological equations as well as direct spacetime geometry quantities involving the acceleration, such as ''geometric dark energy'' from the Ricci scalar. We investigate these interrelationships, including for the case of super acceleration or phantom energy where the fate of the universe may be more gentle than the Big Rip.

  16. Consistency-based rectification of nonrigid registrations

    PubMed Central

    Gass, Tobias; Székely, Gábor; Goksel, Orcun

    2015-01-01

    Abstract. We present a technique to rectify nonrigid registrations by improving their group-wise consistency, which is a widely used unsupervised measure to assess pair-wise registration quality. While pair-wise registration methods cannot guarantee any group-wise consistency, group-wise approaches typically enforce perfect consistency by registering all images to a common reference. However, errors in individual registrations to the reference then propagate, distorting the mean and accumulating in the pair-wise registrations inferred via the reference. Furthermore, the assumption that perfect correspondences exist is not always true, e.g., for interpatient registration. The proposed consistency-based registration rectification (CBRR) method addresses these issues by minimizing the group-wise inconsistency of all pair-wise registrations using a regularized least-squares algorithm. The regularization controls the adherence to the original registration, which is additionally weighted by the local postregistration similarity. This allows CBRR to adaptively improve consistency while locally preserving accurate pair-wise registrations. We show that the resulting registrations are not only more consistent, but also have lower average transformation error when compared to known transformations in simulated data. On clinical data, we show improvements of up to 50% target registration error in breathing motion estimation from four-dimensional MRI and improvements in atlas-based segmentation quality of up to 65% in terms of mean surface distance in three-dimensional (3-D) CT. Such improvement was observed consistently using different registration algorithms, dimensionality (two-dimensional/3-D), and modalities (MRI/CT). PMID:26158083

  17. Advanced Test Accelerator (ATA) injector

    SciTech Connect

    Jackson, C.H.; Bubp, D.G.; Fessenden, T.J.; Hester, R.E.; Neil, V.K.; Paul, A.C.; Prono, D.S.

    1983-03-09

    The ATA injector, developed from experience gained from the Experimental Test Accelerator (ETA) linac, has recently been completed. The injector consists of ten 0.25 MV cells that are used to develop 2.5 MV across a single diode gap. The 10 kA beam is extracted from a 500 cm/sup 2/ plasma cathode at average rates of up to 5 Hz and burst rates to 1 kHz. Pulsed power from 20 water filled blumleins is divided and introduced symmetrically through four ports on each cell. All major insulators are fabricated from filled epoxy castings. With these improvements, the ATA injector is smaller than the ETA injector; has a faster pulse response; has lower voltage stress on insulators and higher ultimate performance. Injector characterization tests began in October 1982. These tests include beam current, energy, and emittance measurements.

  18. Is cosmic acceleration slowing down?

    SciTech Connect

    Shafieloo, Arman; Sahni, Varun; Starobinsky, Alexei A.

    2009-11-15

    We investigate the course of cosmic expansion in its recent past using the Constitution SN Ia sample, along with baryon acoustic oscillations (BAO) and cosmic microwave background (CMB) data. Allowing the equation of state of dark energy (DE) to vary, we find that a coasting model of the universe (q{sub 0}=0) fits the data about as well as Lambda cold dark matter. This effect, which is most clearly seen using the recently introduced Om diagnostic, corresponds to an increase of Om and q at redshifts z < or approx. 0.3. This suggests that cosmic acceleration may have already peaked and that we are currently witnessing its slowing down. The case for evolving DE strengthens if a subsample of the Constitution set consisting of SNLS+ESSENCE+CfA SN Ia data is analyzed in combination with BAO+CMB data. The effect we observe could correspond to DE decaying into dark matter (or something else)

  19. Plasma acceleration above martian magnetic anomalies.

    PubMed

    Lundin, R; Winningham, D; Barabash, S; Frahm, R; Holmström, M; Sauvaud, J-A; Fedorov, A; Asamura, K; Coates, A J; Soobiah, Y; Hsieh, K C; Grande, M; Koskinen, H; Kallio, E; Kozyra, J; Woch, J; Fraenz, M; Brain, D; Luhmann, J; McKenna-Lawler, S; Orsini, R S; Brandt, P; Wurz, P

    2006-02-17

    Auroras are caused by accelerated charged particles precipitating along magnetic field lines into a planetary atmosphere, the auroral brightness being roughly proportional to the precipitating particle energy flux. The Analyzer of Space Plasma and Energetic Atoms experiment on the Mars Express spacecraft has made a detailed study of acceleration processes on the nightside of Mars. We observed accelerated electrons and ions in the deep nightside high-altitude region of Mars that map geographically to interface/cleft regions associated with martian crustal magnetization regions. By integrating electron and ion acceleration energy down to the upper atmosphere, we saw energy fluxes in the range of 1 to 50 milliwatts per square meter per second. These conditions are similar to those producing bright discrete auroras above Earth. Discrete auroras at Mars are therefore expected to be associated with plasma acceleration in diverging magnetic flux tubes above crustal magnetization regions, the auroras being distributed geographically in a complex pattern by the many multipole magnetic field lines extending into space. PMID:16484488

  20. Integrating perspectives on vocal performance and consistency

    PubMed Central

    Sakata, Jon T.; Vehrencamp, Sandra L.

    2012-01-01

    SUMMARY Recent experiments in divergent fields of birdsong have revealed that vocal performance is important for reproductive success and under active control by distinct neural circuits. Vocal consistency, the degree to which the spectral properties (e.g. dominant or fundamental frequency) of song elements are produced consistently from rendition to rendition, has been highlighted as a biologically important aspect of vocal performance. Here, we synthesize functional, developmental and mechanistic (neurophysiological) perspectives to generate an integrated understanding of this facet of vocal performance. Behavioral studies in the field and laboratory have found that vocal consistency is affected by social context, season and development, and, moreover, positively correlated with reproductive success. Mechanistic investigations have revealed a contribution of forebrain and basal ganglia circuits and sex steroid hormones to the control of vocal consistency. Across behavioral, developmental and mechanistic studies, a convergent theme regarding the importance of vocal practice in juvenile and adult songbirds emerges, providing a basis for linking these levels of analysis. By understanding vocal consistency at these levels, we gain an appreciation for the various dimensions of song control and plasticity and argue that genes regulating the function of basal ganglia circuits and sex steroid hormones could be sculpted by sexual selection. PMID:22189763

  1. Report on accelerated corrosion studies.

    SciTech Connect

    Mowry, Curtis Dale; Glass, Sarah Jill; Sorensen, Neil Robert

    2011-03-01

    Sandia National Laboratories (SNL) conducted accelerated atmospheric corrosion testing for the U.S. Consumer Product Safety Commission (CPSC) to help further the understanding of the development of corrosion products on conductor materials in household electrical components exposed to environmental conditions representative of homes constructed with problem drywall. The conditions of the accelerated testing were chosen to produce corrosion product growth that would be consistent with long-term exposure to environments containing humidity and parts per billion (ppb) levels of hydrogen sulfide (H{sub 2}S) that are thought to have been the source of corrosion in electrical components from affected homes. This report documents the test set-up, monitoring of electrical performance of powered electrical components during the exposure, and the materials characterization conducted on wires, screws, and contact plates from selected electrical components. No degradation in electrical performance (measured via voltage drop) was measured during the course of the 8-week exposure, which was approximately equivalent to 40 years of exposure in a light industrial environment. Analyses show that corrosion products consisting of various phases of copper sulfide, copper sulfate, and copper oxide are found on exposed surfaces of the conductor materials including wires, screws, and contact plates. The morphology and the thickness of the corrosion products showed a range of character. In some of the copper wires that were observed, corrosion product had flaked or spalled off the surface, exposing fresh metal to the reaction with the contaminant gasses; however, there was no significant change in the wire cross-sectional area.

  2. Personalized recommendation based on unbiased consistence

    NASA Astrophysics Data System (ADS)

    Zhu, Xuzhen; Tian, Hui; Zhang, Ping; Hu, Zheng; Zhou, Tao

    2015-08-01

    Recently, in physical dynamics, mass-diffusion-based recommendation algorithms on bipartite network provide an efficient solution by automatically pushing possible relevant items to users according to their past preferences. However, traditional mass-diffusion-based algorithms just focus on unidirectional mass diffusion from objects having been collected to those which should be recommended, resulting in a biased causal similarity estimation and not-so-good performance. In this letter, we argue that in many cases, a user's interests are stable, and thus bidirectional mass diffusion abilities, no matter originated from objects having been collected or from those which should be recommended, should be consistently powerful, showing unbiased consistence. We further propose a consistence-based mass diffusion algorithm via bidirectional diffusion against biased causality, outperforming the state-of-the-art recommendation algorithms in disparate real data sets, including Netflix, MovieLens, Amazon and Rate Your Music.

  3. Consistency and derangements in brane tilings

    NASA Astrophysics Data System (ADS)

    Hanany, Amihay; Jejjala, Vishnu; Ramgoolam, Sanjaye; Seong, Rak-Kyeong

    2016-09-01

    Brane tilings describe Lagrangians (vector multiplets, chiral multiplets, and the superpotential) of four-dimensional { N }=1 supersymmetric gauge theories. These theories, written in terms of a bipartite graph on a torus, correspond to worldvolume theories on N D3-branes probing a toric Calabi–Yau threefold singularity. A pair of permutations compactly encapsulates the data necessary to specify a brane tiling. We show that geometric consistency for brane tilings, which ensures that the corresponding quantum field theories are well behaved, imposes constraints on the pair of permutations, restricting certain products constructed from the pair to have no one-cycles. Permutations without one-cycles are known as derangements. We illustrate this formulation of consistency with known brane tilings. Counting formulas for consistent brane tilings with an arbitrary number of chiral bifundamental fields are written down in terms of delta functions over symmetric groups.

  4. THE SPECIFIC ACCELERATION RATE IN LOOP-STRUCTURED SOLAR FLARES-IMPLICATIONS FOR ELECTRON ACCELERATION MODELS

    SciTech Connect

    Guo, Jingnan; Emslie, A. Gordon; Piana, Michele E-mail: piana@dima.unige.it

    2013-03-20

    We analyze electron flux maps based on RHESSI hard X-ray imaging spectroscopy data for a number of extended coronal-loop flare events. For each event, we determine the variation of the characteristic loop length L with electron energy E, and we fit this observed behavior with models that incorporate an extended acceleration region and an exterior 'propagation' region, and which may include collisional modification of the accelerated electron spectrum inside the acceleration region. The models are characterized by two parameters: the plasma density n in, and the longitudinal extent L{sub 0} of, the acceleration region. Determination of the best-fit values of these parameters permits inference of the volume that encompasses the acceleration region and of the total number of particles within it. It is then straightforward to compute values for the emission filling factor and for the specific acceleration rate (electrons s{sup -1} per ambient electron above a chosen reference energy). For the 24 events studied, the range of inferred filling factors is consistent with a value of unity. The inferred mean value of the specific acceleration rate above E{sub 0} = 20 keV is {approx}10{sup -2} s{sup -1}, with a 1{sigma} spread of about a half-order-of-magnitude above and below this value. We compare these values with the predictions of several models, including acceleration by large-scale, weak (sub-Dreicer) fields, by strong (super-Dreicer) electric fields in a reconnecting current sheet, and by stochastic acceleration processes.

  5. Many human accelerated regions are developmental enhancers

    PubMed Central

    Capra, John A.; Erwin, Genevieve D.; McKinsey, Gabriel; Rubenstein, John L. R.; Pollard, Katherine S.

    2013-01-01

    The genetic changes underlying the dramatic differences in form and function between humans and other primates are largely unknown, although it is clear that gene regulatory changes play an important role. To identify regulatory sequences with potentially human-specific functions, we and others used comparative genomics to find non-coding regions conserved across mammals that have acquired many sequence changes in humans since divergence from chimpanzees. These regions are good candidates for performing human-specific regulatory functions. Here, we analysed the DNA sequence, evolutionary history, histone modifications, chromatin state and transcription factor (TF) binding sites of a combined set of 2649 non-coding human accelerated regions (ncHARs) and predicted that at least 30% of them function as developmental enhancers. We prioritized the predicted ncHAR enhancers using analysis of TF binding site gain and loss, along with the functional annotations and expression patterns of nearby genes. We then tested both the human and chimpanzee sequence for 29 ncHARs in transgenic mice, and found 24 novel developmental enhancers active in both species, 17 of which had very consistent patterns of activity in specific embryonic tissues. Of these ncHAR enhancers, five drove expression patterns suggestive of different activity for the human and chimpanzee sequence at embryonic day 11.5. The changes to human non-coding DNA in these ncHAR enhancers may modify the complex patterns of gene expression necessary for proper development in a human-specific manner and are thus promising candidates for understanding the genetic basis of human-specific biology. PMID:24218637

  6. Prospects for Accelerator Technology

    NASA Astrophysics Data System (ADS)

    Todd, Alan

    2011-02-01

    Accelerator technology today is a greater than US$5 billion per annum business. Development of higher-performance technology with improved reliability that delivers reduced system size and life cycle cost is expected to significantly increase the total accelerator technology market and open up new application sales. Potential future directions are identified and pitfalls in new market penetration are considered. Both of the present big market segments, medical radiation therapy units and semiconductor ion implanters, are approaching the "maturity" phase of their product cycles, where incremental development rather than paradigm shifts is the norm, but they should continue to dominate commercial sales for some time. It is anticipated that large discovery-science accelerators will continue to provide a specialty market beset by the unpredictable cycles resulting from the scale of the projects themselves, coupled with external political and economic drivers. Although fraught with differing market entry difficulties, the security and environmental markets, together with new, as yet unrealized, industrial material processing applications, are expected to provide the bulk of future commercial accelerator technology growth.

  7. Radioisotope Dating with Accelerators.

    ERIC Educational Resources Information Center

    Muller, Richard A.

    1979-01-01

    Explains a new method of detecting radioactive isotopes by counting their accelerated ions rather than the atoms that decay during the counting period. This method increases the sensitivity by several orders of magnitude, and allows one to find the ages of much older and smaller samples. (GA)

  8. Two-beam accelerator

    SciTech Connect

    Selph, F.B.

    1984-09-01

    In the two-beam accelerator (TBA) concept, an electron linear accelerator structure is established in which two beams propagate. One is an intense low energy beam that is made to undergo free electron lasing to produce microwaves. These microwaves are then coupled to another part of the structure where they act to produce a high longitudinal electric gradient that is used to accelerate a second relatively low intensity electron beam to very high energies. The TBA was originally suggested by Sessler as a possible means for economically achieving linear collider energies of 100 GeV and above. Although still in a conceptual stage, the TBA is an inherently plausible concept that combines the free electron laser (FEL) with several well-known technologies - high current induction linacs, microwave waveguides, and traveling-wave linac structures - in a novel and interesting way. Two characteristics of the TBA that make it a particularly suitable candidate for achieving high energies are its ability to operate at higher frequencies than typical present-day linacs (say 30 GHz as compared with 3 GHz), and to be an efficient means for delivering power to a hitherto unattainable high-gradient structure (say 250 MV/m) that the higher frequency makes possible. These high accelerating gradients will permit much shorter linac structures for a given energy.

  9. FPGA Verification Accelerator (FVAX)

    NASA Technical Reports Server (NTRS)

    Oh, Jane; Burke, Gary

    2008-01-01

    Is Verification Acceleration Possible? - Increasing the visibility of the internal nodes of the FPGA results in much faster debug time - Forcing internal signals directly allows a problem condition to be setup very quickly center dot Is this all? - No, this is part of a comprehensive effort to improve the JPL FPGA design and V&V process.

  10. Pulsed electromagnetic gas acceleration

    NASA Technical Reports Server (NTRS)

    Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

    1974-01-01

    Detailed measurements of the axial velocity profile and electromagnetic structure of a high power, quasi-steady MPD discharge are used to formulate a gasdynamic model of the acceleration process. Conceptually dividing the accelerated plasma into an inner flow and an outer flow, it is found that more than two-thirds of the total power in the plasma is deposited in the inner flow, accelerating it to an exhaust velocity of 12.5 km/sec. The outer flow, which is accelerated to a velocity of only 6.2 km/sec, appears to provide a current conduction path between the inner flow and the anode. Related cathode studies have shown that the critical current for the onset of terminal voltage fluctuations, which was recently shown to be a function of the cathode area, appears to reach an asymptote for cathodes of very large surface area. Detailed floating potential measurements show that the fluctuations are confined to the vicinity of the cathode and hence reflect a cathode emission process rather than a fundamental limit on MPD performance.

  11. Anticholinergic substances: A single consistent conformation

    PubMed Central

    Pauling, Peter; Datta, Narayandas

    1980-01-01

    An interactive computer-graphics analysis of 24 antagonists of acetylcholine at peripheral autonomic post-ganglionic (muscarinic) nervous junctions and at similar junctions in the central nervous system, the crystal structures of which are known, has led to the determination of a single, consistent, energetically favorable conformation for all 24 substances, although their observed crystal structure conformations vary widely. The absolute configuration and the single, consistent (ideal) conformation of the chemical groups required for maximum anticholinergic activity are described quantitatively. Images PMID:16592775

  12. Consistent Data Distribution Over Optical Links

    NASA Technical Reports Server (NTRS)

    Palumbo, Daniel L.

    1988-01-01

    Fiber optics combined with IDE's provide consistent data communication between fault-tolerant computers. Data-transmission-checking system designed to provide consistent and reliable data communications for fault-tolerant and highly reliable computers. New technique performs variant of algorithm for fault-tolerant computers and uses fiber optics and independent decision elements (IDE's) to require fewer processors and fewer transmissions of messages. Enables fault-tolerant computers operating at different levels of redundancy to communicate with each other over triply redundant bus. Level of redundancy limited only by maximum number of wavelengths active on bus.

  13. Accuracy and consistency of modern elastomeric pumps.

    PubMed

    Weisman, Robyn S; Missair, Andres; Pham, Phung; Gutierrez, Juan F; Gebhard, Ralf E

    2014-01-01

    Continuous peripheral nerve blockade has become a popular method of achieving postoperative analgesia for many surgical procedures. The safety and reliability of infusion pumps are dependent on their flow rate accuracy and consistency. Knowledge of pump rate profiles can help physicians determine which infusion pump is best suited for their clinical applications and specific patient population. Several studies have investigated the accuracy of portable infusion pumps. Using methodology similar to that used by Ilfeld et al, we investigated the accuracy and consistency of several current elastomeric pumps. PMID:25140510

  14. Dynamically consistent Jacobian inverse for mobile manipulators

    NASA Astrophysics Data System (ADS)

    Ratajczak, Joanna; Tchoń, Krzysztof

    2016-06-01

    By analogy to the definition of the dynamically consistent Jacobian inverse for robotic manipulators, we have designed a dynamically consistent Jacobian inverse for mobile manipulators built of a non-holonomic mobile platform and a holonomic on-board manipulator. The endogenous configuration space approach has been exploited as a source of conceptual guidelines. The new inverse guarantees a decoupling of the motion in the operational space from the forces exerted in the endogenous configuration space and annihilated by the dual Jacobian inverse. A performance study of the new Jacobian inverse as a tool for motion planning is presented.

  15. Dualising consistent IIA/IIB truncations

    NASA Astrophysics Data System (ADS)

    Malek, Emanuel; Samtleben, Henning

    2015-12-01

    We use exceptional field theory to establish a duality between certain consistent 7-dimensional truncations with maximal SUSY from IIA to IIB. We use this technique to obtain new consistent truncations of IIB on S 3 and H p,q and work out the explicit reduction formulas in the internal sector. We also present uplifts for other gaugings of 7-d maximal SUGRA, including theories with a trombone gauging. Some of the latter can only be obtained by a non-geometric compactification.

  16. The FRC Acceleration Space Thruster (FAST) Experiment

    NASA Technical Reports Server (NTRS)

    Martin, Adam; Eskridge, Richard; Houts, Mike; Slough, John; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    The objective of the FRC (Field Reversed Configuration) Acceleration Space Thruster (FAST) Experiment is to investigate the use of a repetitive FRC source as a thruster, specifically for an NEP (nuclear electric propulsion) system. The Field Reversed Configuration is a plasmoid with a closed poloidal field line structure, and has been extensively studied as a fusion reactor core. An FRC thruster works by repetitively producing FRCs and accelerating them to high velocity. An FRC thruster should be capable of I(sub sp)'s in the range of 5,000 - 25,000 seconds and efficiencies in the range of 60 - 80 %. In addition, they can have thrust densities as high as 10(exp 6) N/m2, and as they are inductively formed, they do not suffer from electrode erosion. The jet-power should be scalable from the low to the high power regime. The FAST experiment consists of a theta-pinch formation chamber, followed by an acceleration stage. Initially, we will produce and accelerate single FRCs. The initial focus of the experiment will be on the ionization, formation and acceleration of a single plasmoid, so as to determine the likely efficiency and I(sub sp). Subsequently, we will modify the device for repetitive burst-mode operation (5-10 shots). A variety of diagnostics are or will be available for this work, including a HeNe interferometer, high-speed cameras, and a Thomson-scattering system. The status of the experiment will be described.

  17. Superconducting Cavities for the APT Accelerator

    NASA Astrophysics Data System (ADS)

    Krawczyk, Frank L.; Gentzlinger, Robert C.; Montoya, Debbie I.; Rusnak, Brian; Shapiro, Alan H.

    1997-05-01

    One type of design for an Accelerator Production of Tritium (APT) facility being investigated at LANL consists mainly of a linear accelerator using superconducting rf cavities for the acceleration of a high current cw proton beam. For electron accelerators with particles moving at almost the speed of light (β=1.0), resonators with a rounded shape, consisting of elliptical, circular and straight sections, are well established. They are referred to as ``elliptical'' cavities. For the APT-design, this shape has been adapted for much slower proton beams from a β of less than 0.64 to slightly above 0.82. This is a new energy range, in which resonators of an elliptical type have never been used before. Simulations with the well-proven electromagnetic modeling tools MAFIA and SUPERFISH were performed. The structures have been optimized for their rf properties as well as for beam dynamics requirements. Single cell test cavities are under construction and will be tested in our structures laboratory. Their performance in terms of obtainable gradients, Q and multipacting behavior, as well as a comparison of the major rf parameters with the results of the cavity simulations, will be reported.

  18. Transversely accelerated ions in the topside ionosphere

    NASA Technical Reports Server (NTRS)

    Retterer, John M.; Chang, Tom; Jasperse, J. R.

    1994-01-01

    Data from the rocket campaigns Mechanism in the Auroral Region for Ion Energization (MARIE) and TOpside Probe of the Auroral Zone (TOPAZ) III, within regions of low-altitude transversely accelerated ions, are interpreted to explain the acceleration of the ions. Using the Monte Carlo kinetic technique to evaluate the ion heating produced by the simultaneously observed lower hybrid waves, we find that their observed electric field amplitudes are sufficient to explain the observed ion energies in the MARIE event. Much of the uncertainty in evaluating the efficiency of a plasma wave induced particle heating process which is dependent on a velocity resonance comes from the lack of information on the phase velocities of the waves. In the case of the MARIE observations, our modeling efforts show that features in the ion velocity distribution are consistent with the wave phase velocities inferred from interferometer measurements of wavelengths. The lower hybrid waves with which low-altitude transversely accelerated ions are associated are frequently observed to be concentrated in small-scale wave packets called 'spikelets'. We demonstrate through the scaling of the size of these wave packets that they are consistent with the theory of lower hybrid collapse. Using the Monte Carlo technique, we find that if the lower hybrid field energy is concentrated in these wave packets, it is still adequate to accelerate the ionospheric ions to the observed energies.

  19. Menopause accelerates biological aging.

    PubMed

    Levine, Morgan E; Lu, Ake T; Chen, Brian H; Hernandez, Dena G; Singleton, Andrew B; Ferrucci, Luigi; Bandinelli, Stefania; Salfati, Elias; Manson, JoAnn E; Quach, Austin; Kusters, Cynthia D J; Kuh, Diana; Wong, Andrew; Teschendorff, Andrew E; Widschwendter, Martin; Ritz, Beate R; Absher, Devin; Assimes, Themistocles L; Horvath, Steve

    2016-08-16

    Although epigenetic processes have been linked to aging and disease in other systems, it is not yet known whether they relate to reproductive aging. Recently, we developed a highly accurate epigenetic biomarker of age (known as the "epigenetic clock"), which is based on DNA methylation levels. Here we carry out an epigenetic clock analysis of blood, saliva, and buccal epithelium using data from four large studies: the Women's Health Initiative (n = 1,864); Invecchiare nel Chianti (n = 200); Parkinson's disease, Environment, and Genes (n = 256); and the United Kingdom Medical Research Council National Survey of Health and Development (n = 790). We find that increased epigenetic age acceleration in blood is significantly associated with earlier menopause (P = 0.00091), bilateral oophorectomy (P = 0.0018), and a longer time since menopause (P = 0.017). Conversely, epigenetic age acceleration in buccal epithelium and saliva do not relate to age at menopause; however, a higher epigenetic age in saliva is exhibited in women who undergo bilateral oophorectomy (P = 0.0079), while a lower epigenetic age in buccal epithelium was found for women who underwent menopausal hormone therapy (P = 0.00078). Using genetic data, we find evidence of coheritability between age at menopause and epigenetic age acceleration in blood. Using Mendelian randomization analysis, we find that two SNPs that are highly associated with age at menopause exhibit a significant association with epigenetic age acceleration. Overall, our Mendelian randomization approach and other lines of evidence suggest that menopause accelerates epigenetic aging of blood, but mechanistic studies will be needed to dissect cause-and-effect relationships further. PMID:27457926

  20. Self-Consistent Non-Stationary Theory of Multipactor in DLA Structures

    SciTech Connect

    Sinitsyn, O. V.; Nusinovich, G. S.; Antonsen, T. M.; Kishek, R.

    2009-01-22

    In this paper a non-stationary self-consistent theoretical model of multipactor in dielectric loaded accelerator structures is proposed. In comparison with our previous work, the effects of the cylindricity are included. The corresponding numerical implementation of the model is described and some simulation results are shown.

  1. Self-Consistent Magnetosphere-Ionosphere Coupling

    NASA Technical Reports Server (NTRS)

    Six, N. Frank (Technical Monitor); Khazanov, G. V.; Newman, T. S.; Liemohn, M. W.; Fok, M. C.; Spiro, R. W.

    2002-01-01

    A self-consistent ring current (RC) model has been developed that couples electron and ion magnetospheric dynamics with the calculation of the electric field. Two new features were taken into account in order to close the self-consistent magnetosphere-ionosphere coupling loop. First, in addition to the RC ions, we have solved an electron kinetic equation in our model. Second, using the relation of Galand and Richmond, we have calculated the height integrated ionospheric conductances as a function of the precipitated high energy magnetospheric electrons and ions that are produced by our model. To validate the results of our model we simulate the magnetic storm of May 2, 1986, a storm that has been comprehensively studied by Fok et al., and have compared our results with different theoretical approaches. The self-consistent inclusion of the hot electrons and their effect on the conductance results in deeper penetration of the magnetospheric electric field. In addition, a slight westward rotation of the potential pattern (compared to previous self-consistent results) is evident in the inner magnetosphere. These effects change the hot plasma distribution, especially by allowing increased access of plasma sheet ions and electrons to low L shells.

  2. Developing consistent time series landsat data products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Landsat series satellite has provided earth observation data record continuously since early 1970s. There are increasing demands on having a consistent time series of Landsat data products. In this presentation, I will summarize the work supported by the USGS Landsat Science Team project from 20...

  3. 36 CFR 241.22 - Consistency determinations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... FISH AND WILDLIFE Conservation of Fish, Wildlife, and Their Habitat, Chugach National Forest, Alaska... conservation of fish, wildlife, and their habitat. A use or activity may be determined to be consistent if it will not materially interfere with or detract from the conservation of fish, wildlife and their...

  4. 36 CFR 241.22 - Consistency determinations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... FISH AND WILDLIFE Conservation of Fish, Wildlife, and Their Habitat, Chugach National Forest, Alaska... conservation of fish, wildlife, and their habitat. A use or activity may be determined to be consistent if it will not materially interfere with or detract from the conservation of fish, wildlife and their...

  5. 36 CFR 241.22 - Consistency determinations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... FISH AND WILDLIFE Conservation of Fish, Wildlife, and Their Habitat, Chugach National Forest, Alaska... conservation of fish, wildlife, and their habitat. A use or activity may be determined to be consistent if it will not materially interfere with or detract from the conservation of fish, wildlife and their...

  6. Effecting Consistency across Curriculum: A Case Study

    ERIC Educational Resources Information Center

    Devasagayam, P. Raj; Mahaffey, Thomas R.

    2008-01-01

    Continuous quality improvement is the clarion call across all business schools which is driving the emphasis on assessing the attainment of learning outcomes. An issue that deems special attention in assurance of learning outcomes is related to consistency across courses and, more specifically, across multiple sections of the same course taught by…

  7. Grading for Speed, Consistency, and Accuracy.

    ERIC Educational Resources Information Center

    Kryder, LeeAnne G.

    2003-01-01

    Explains the rubrics the author has developed to assure some degree of consistency in grading among instructors and teaching assistants in various sections of the same writing course. Finds these rubrics particularly useful for evaluating individual student performance in group projects. (SG)

  8. 24 CFR 91.510 - Consistency determinations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Consistency determinations. 91.510 Section 91.510 Housing and Urban Development Office of the Secretary, Department of Housing and Urban... HOPWA grant is a city that is the most populous unit of general local government in an EMSA, it...

  9. Energy confinement and profile consistency in TFTR

    SciTech Connect

    Goldston, R.J.; Arunasalan, V.; Bell, M.G.; Bitter, M.; Blanchard, W.R.; Bretz, N.L.; Budny, R.; bush, C.E.; Callen, J.D.; Cohen, S.A.

    1987-04-01

    A new regime of enhanced energy confinement has been observed on TFTR with neutral beam injection at low plasma current. It is characterized by extremely peaked electron density profiles and broad electron temperature profiles. The electron temperature profile shapes violate the concept of profile consistency in which T/sub e/(O)//sub v/ is assumed to be a tightly constrained function of q/sub a/, but they are in good agreement with a form of profile consistency based on examining the temperature profile shape outside the plasma core. The enhanced confinement regime is only obtained with a highly degassed limiter; in discharges with gas-filled limiters convective losses are calculated to dominate the edge electron power balance. Consistent with the constraint of profile consistency, global confinement is degraded in these cases. The best heating results in the enhanced confinement regime are obtained with nearly balanced co- and counter-injection. Much of the difference between balanced and co-only injection can be explained on the basis of classically predicted effects associated with plasma rotation.

  10. Consistency criteria for generalized Cuddeford systems

    NASA Astrophysics Data System (ADS)

    Ciotti, Luca; Morganti, Lucia

    2010-01-01

    General criteria to check the positivity of the distribution function (phase-space consistency) of stellar systems of assigned density and anisotropy profile are useful starting points in Jeans-based modelling. Here, we substantially extend previous results, and present the inversion formula and the analytical necessary and sufficient conditions for phase-space consistency of the family of multicomponent Cuddeford spherical systems: the distribution function of each density component of these systems is defined as the sum of an arbitrary number of Cuddeford distribution functions with arbitrary values of the anisotropy radius, but identical angular momentum exponent. The radial trend of anisotropy that can be realized by these models is therefore very general. As a surprising byproduct of our study, we found that the `central cusp-anisotropy theorem' (a necessary condition for consistency relating the values of the central density slope and of the anisotropy parameter) holds not only at the centre but also at all radii in consistent multicomponent generalized Cuddeford systems. This last result suggests that the so-called mass-anisotropy degeneracy could be less severe than what is sometimes feared.

  11. Consistency of Toddler Engagement across Two Settings

    ERIC Educational Resources Information Center

    Aguiar, Cecilia; McWilliam, R. A.

    2013-01-01

    This study documented the consistency of child engagement across two settings, toddler child care classrooms and mother-child dyadic play. One hundred twelve children, aged 14-36 months (M = 25.17, SD = 6.06), randomly selected from 30 toddler child care classrooms from the district of Porto, Portugal, participated. Levels of engagement were…

  12. Consistency of Students' Pace in Online Learning

    ERIC Educational Resources Information Center

    Hershkovitz, Arnon; Nachmias, Rafi

    2009-01-01

    The purpose of this study is to investigate the consistency of students' behavior regarding their pace of actions over sessions within an online course. Pace in a session is defined as the number of logged actions divided by session length (in minutes). Log files of 6,112 students were collected, and datasets were constructed for examining pace…

  13. Environmental Decision Support with Consistent Metrics

    EPA Science Inventory

    One of the most effective ways to pursue environmental progress is through the use of consistent metrics within a decision making framework. The US Environmental Protection Agency’s Sustainable Technology Division has developed TRACI, the Tool for the Reduction and Assessment of...

  14. Consistent Visual Analyses of Intrasubject Data

    ERIC Educational Resources Information Center

    Kahng, SungWoo; Chung, Kyong-Mee; Gutshall, Katharine; Pitts, Steven C.; Kao, Joyce; Girolami, Kelli

    2010-01-01

    Visual inspection of single-case data is the primary method of interpretation of the effects of an independent variable on a dependent variable in applied behavior analysis. The purpose of the current study was to replicate and extend the results of DeProspero and Cohen (1979) by reexamining the consistency of visual analysis across raters. We…

  15. Taking Another Look: Sensuous, Consistent Form.

    ERIC Educational Resources Information Center

    Townley, Mary Ross

    1983-01-01

    There is a natural progression from making single objects to creating sculpture. By modeling the forms of objects like funnels and light bulbs, students become aware of the quality of curves and the edges of angles. Sculptural form in architecture can be understood as consistency in the forms. (CS)

  16. Accelerated luminophore discovery through combinatorial synthesis.

    PubMed

    Lowry, Michael S; Hudson, William R; Pascal, Robert A; Bernhard, Stefan

    2004-11-01

    A method for accelerating the discovery of ionic luminophores using combinatorial techniques is reported. The photophysical properties of the resulting transition-metal-based chromophores were compared against a series of analogous, traditionally prepared species. The strong overlap between these two sets confirms the identity of the parallel synthesis products and supports the truthfulness of the combinatorial results. Further support for the combinatorial method comes from the adherence of these complexes to the energy gap law. The relationship between the structure of a complex and its photophysical properties was also considered, and static DFT calculations were used to assess whether it is feasible to predict the luminescent behavior of novel materials. PMID:15506778

  17. Stacked insulator induction accelerator gaps

    SciTech Connect

    Houck, T.I.; Westenskow, G.A.; Kim, J.S.; Eylon, S.; Henestroza, E.; Yu, S.S.; Vanecek, D.

    1997-05-01

    Stacked insulators, with alternating layers of insulating material and conducting film, have been shown to support high surface electrical field stresses. We have investigated the application of the stacked insulator technology to the design of induction accelerator modules for the Relativistic-Klystron Two-Beam Accelerator program. The rf properties of the accelerating gaps using stacked insulators, particularly the impedance at frequencies above the beam pipe cutoff frequency, are investigated. Low impedance is critical for Relativistic-Klystron Two-Beam Accelerator applications where a high current, bunched beam is trsnsported through many accelerating gaps. An induction accelerator module designs using a stacked insulator is presented.

  18. Double layers acting as particles accelerators

    SciTech Connect

    Sanduloviciu, M.; Lozneanu, E.

    1995-12-31

    It is shown that self-consistent stable and unstable double layers generated in plasma after a self-organisation process are able to accelerate charged particles. The implication of cosmic double layers (Dls) in the acceleration of electrical charged particles long been advocated by Alfven and his Stockholm school is today disputed by argument that static electric fields associated with Dls are conservative and consequently the line integral of the electric field outside the DL balances the line integral inside it. Related with this dispute we will evidence some, so far not considered, facts which are in our opinion arguments that aurora Dls are able to energize particles. For justifying this assertion we start from recent experimental results concerning the phenomenology of self-consistent Dls whose generation involve beside ionisations the neutrals excitations which are at tile origin of the light phenomena as those observed in auroras.

  19. Classical and Quantum Consistency of the DGP Model

    NASA Astrophysics Data System (ADS)

    Nicolis, Alberto; Rattazzi, Riccardo

    2004-06-01

    We study the Dvali-Gabadadze-Porrati model by the method of the boundary effective action. The truncation of this action to the bending mode pi consistently describes physics in a wide range of regimes both at the classical and at the quantum level. The Vainshtein effect, which restores agreement with precise tests of general relativity, follows straightforwardly. We give a simple and general proof of stability, i.e. absence of ghosts in the fluctuations, valid for most of the relevant cases, like for instance the spherical source in asymptotically flat space. However we confirm that around certain interesting self-accelerating cosmological solutions there is a ghost. We consider the issue of quantum corrections. Around flat space pi becomes strongly coupled below a macroscopic length of 1000 km, thus impairing the predictivity of the model. Indeed the tower of higher dimensional operators which is expected by a generic UV completion of the model limits predictivity at even larger length scales. We outline a non-generic but consistent choice of counterterms for which this disaster does not happen and for which the model remains calculable and successful in all the astrophysical situations of interest. By this choice, the extrinsic curvature Kmunu acts roughly like a dilaton field controlling the strength of the interaction and the cut-off scale at each space-time point. At the surface of Earth the cutoff is ~ 1 cm but it is unlikely that the associated quantum effects be observable in table top experiments.

  20. Self-Consistent Superthermal Electron Effects on Plasmaspheric Refilling

    NASA Technical Reports Server (NTRS)

    Liemohn, M. W.; Khazanov, G. V.; Moore, T. E.; Guiter, S. M.

    1997-01-01

    The effects of self-consistently including superthermal electrons in the definition of the ambipolar electric field are investigated for the case of plasmaspheric refilling after a geomagnetic storm. By using the total electron population in the hydrodynamic equations, a method for incorporating superthermal electron parameters in the electric field and electron temperature calculation is developed. Also, the ambipolar electric field is included in the kinetic equation for the superthermal electrons through a change of variables using the total energy and the first adiabatic invariant. Calculations based on these changes are performed by coupling time-dependent models of the thermal plasma and superthermal electrons. Results from this treatment of the electric field and the self-consistent development of the solution are discussed in detail. Specifically, there is a decreased thermal electron density in the plasmasphere during the first few minutes of refilling, a slightly accelerated proton shock front, and a decreased superthermal electron flux due to the deceleration by the electric field. The timescales of plasmaspheric refilling are discussed and determined to be somewhat shorter than previously calculated for the thermal plasma and superthermal electron population due to the effects of the field-aligned potential.

  1. Preliminary consideration of a double, 480 GeV, fast cycling proton accelerator for production of neutrino beams at Fermilab

    SciTech Connect

    Piekarz, Henryk; Hays, Steven; /Fermilab

    2007-03-01

    We propose to build the DSF-MR (Double Super-Ferric Main Ring), 480 GeV, fast-cycling (2 second repetition rate) two-beam proton accelerator in the Main Ring tunnel of Fermilab. This accelerator design is based on the super-ferric magnet technology developed for the VLHC, and extended recently to the proposed LER injector for the LHC and fast cycling SF-SPS at CERN. The DSF-MR accelerator system will constitute the final stage of the proton source enabling production of two neutrino beams separated by 2 second time period. These beams will be sent alternately to two detectors located at {approx} 3000 km and {approx} 7500 km away from Fermilab. It is expected that combination of the results from these experiments will offer more than 3 order of magnitudes increased sensitivity for detection and measurement of neutrino oscillations with respect to expectations in any current experiment, and thus may truly enable opening the window into the physics beyond the Standard Model. We examine potential sites for the long baseline neutrino detectors accepting beams from Fermilab. The current injection system consisting of 400 MeV Linac, 8 GeV Booster and the Main Injector can be used to accelerate protons to 45 GeV before transferring them to the DSF-MR. The implementation of the DSF-MR will allow for an 8-fold increase in beam power on the neutrino production target. In this note we outline the proposed new arrangement of the Fermilab accelerator complex. We also briefly describe the DSF-MR magnet design and its power supply, and discuss necessary upgrade of the Tevatron RF system for the use with the DSF-MR accelerator. Finally, we outline the required R&D, cost estimate and possible timeline for the implementation of the DSF-MR accelerator.

  2. The ideas behind self-consistent expansion

    NASA Astrophysics Data System (ADS)

    Schwartz, Moshe; Katzav, Eytan

    2008-04-01

    In recent years we have witnessed a growing interest in various non-equilibrium systems described in terms of stochastic nonlinear field theories. In some of those systems, like KPZ and related models, the interesting behavior is in the strong coupling regime, which is inaccessible by traditional perturbative treatments such as dynamical renormalization group (DRG). A useful tool in the study of such systems is the self-consistent expansion (SCE), which might be said to generate its own 'small parameter'. The self-consistent expansion (SCE) has the advantage that its structure is just that of a regular expansion, the only difference is that the simple system around which the expansion is performed is adjustable. The purpose of this paper is to present the method in a simple and understandable way that hopefully will make it accessible to a wider public working on non-equilibrium statistical physics.

  3. Consistent Numerical Expressions for Precession Formulae.

    NASA Astrophysics Data System (ADS)

    Soma, M.

    The precession formulae by Lieske et al. (1977) have been used since 1984 for calculating apparent positions and reducing astrometric observations of celestial objects. These formulae are based on the IAU (1976) Astronomical Constants, some of which deviate from their recently determined values. They are also derived using the secular variations of the ecliptic pole from Newcomb's theory, which is not consistent with the recent planetary theories. Accordingly Simon et al. (1994) developed new precession formulae using the recently determined astronomical constants and also being based on the new planetary theory VSOP87. There are two differing definitions of the ecliptic: ecliptic in the inertial sense and ecliptic in the rotating sense (Standish 1981). The ecliptic given by the VSOP87 theory is that in the inertial sense, but the value for obliquity Simon et al. used is the obliquity in the rotating sense. Therefore their precession formulae has inconsistency. This paper gives corrections for consistent precession formulae.

  4. Consistent Pauli reduction on group manifolds

    NASA Astrophysics Data System (ADS)

    Baguet, A.; Pope, C. N.; Samtleben, H.

    2016-01-01

    We prove an old conjecture by Duff, Nilsson, Pope and Warner asserting that the NSsbnd NS sector of supergravity (and more general the bosonic string) allows for a consistent Pauli reduction on any d-dimensional group manifold G, keeping the full set of gauge bosons of the G × G isometry group of the bi-invariant metric on G. The main tool of the construction is a particular generalised Scherk-Schwarz reduction ansatz in double field theory which we explicitly construct in terms of the group's Killing vectors. Examples include the consistent reduction from ten dimensions on S3 ×S3 and on similar product spaces. The construction is another example of globally geometric non-toroidal compactifications inducing non-geometric fluxes.

  5. Consistency relation for cosmic magnetic fields

    NASA Astrophysics Data System (ADS)

    Jain, Rajeev Kumar; Sloth, Martin S.

    2012-12-01

    If cosmic magnetic fields are indeed produced during inflation, they are likely to be correlated with the scalar metric perturbations that are responsible for the cosmic microwave background anisotropies and large scale structure. Within an archetypical model of inflationary magnetogenesis, we show that there exists a new simple consistency relation for the non-Gaussian cross correlation function of the scalar metric perturbation with two powers of the magnetic field in the squeezed limit where the momentum of the metric perturbation vanishes. We emphasize that such a consistency relation turns out to be extremely useful to test some recent calculations in the literature. Apart from primordial non-Gaussianity induced by the curvature perturbations, such a cross correlation might provide a new observational probe of inflation and can in principle reveal the primordial nature of cosmic magnetic fields.

  6. Self-Consistent Scattering and Transport Calculations

    NASA Astrophysics Data System (ADS)

    Hansen, S. B.; Grabowski, P. E.

    2015-11-01

    An average-atom model with ion correlations provides a compact and complete description of atomic-scale physics in dense, finite-temperature plasmas. The self-consistent ionic and electronic distributions from the model enable calculation of x-ray scattering signals and conductivities for material across a wide range of temperatures and densities. We propose a definition for the bound electronic states that ensures smooth behavior of these measurable properties under pressure ionization and compare the predictions of this model with those of less consistent models for Be, C, Al, and Fe. SNL is a multi-program laboratory managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corp, for the U.S. DoE NNSA under contract DE-AC04-94AL85000. This work was supported by DoE OFES Early Career grant FWP-14-017426.

  7. The effect of stochastic re-acceleration on the energy spectrum of shock-accelerated protons

    SciTech Connect

    Afanasiev, Alexandr; Vainio, Rami; Kocharov, Leon

    2014-07-20

    The energy spectra of particles in gradual solar energetic particle (SEP) events do not always have a power-law form attributed to the diffusive shock acceleration mechanism. In particular, the observed spectra in major SEP events can take the form of a broken (double) power law. In this paper, we study the effect of a process that can modify the power-law spectral form produced by the diffusive shock acceleration: the stochastic re-acceleration of energetic protons by enhanced Alfvénic turbulence in the downstream region of a shock wave. There are arguments suggesting that this process can be important when the shock propagates in the corona. We consider a coronal magnetic loop traversed by a shock and perform Monte Carlo simulations of interactions of shock-accelerated protons with Alfvén waves in the loop. The wave-particle interactions are treated self-consistently, so the finiteness of the available turbulent energy is taken into account. The initial energy spectrum of particles is taken to be a power law. The simulations reveal that the stochastic re-acceleration leads either to the formation of a spectrum that is described in a wide energy range by a power law (although the resulting power-law index is different from the initial one) or to a broken power-law spectrum. The resulting spectral form is determined by the ratio of the energy density of shock-accelerated protons to the wave energy density in the shock's downstream region.

  8. Self-Consistent Random Phase Approximation

    NASA Astrophysics Data System (ADS)

    Rohr, Daniel; Hellgren, Maria; Gross, E. K. U.

    2012-02-01

    We report self-consistent Random Phase Approximation (RPA) calculations within the Density Functional Theory. The calculations are performed by the direct minimization scheme for the optimized effective potential method developed by Yang et al. [1]. We show results for the dissociation curve of H2^+, H2 and LiH with the RPA, where the exchange correlation kernel has been set to zero. For H2^+ and H2 we also show results for RPAX, where the exact exchange kernel has been included. The RPA, in general, over-correlates. At intermediate distances a maximum is obtained that lies above the exact energy. This is known from non-self-consistent calculations and is still present in the self-consistent results. The RPAX energies are higher than the RPA energies. At equilibrium distance they accurately reproduce the exact total energy. In the dissociation limit they improve upon RPA, but are still too low. For H2^+ the RPAX correlation energy is zero. Consequently, RPAX gives the exact dissociation curve. We also present the local potentials. They indicate that a peak at the bond midpoint builds up with increasing bond distance. This is expected for the exact KS potential.[4pt] [1] W. Yang, and Q. Wu, Phys. Rev. Lett., 89, 143002 (2002)

  9. Towards a consistent modeling framework across scales

    NASA Astrophysics Data System (ADS)

    Jagers, B.

    2013-12-01

    The morphodynamic evolution of river-delta-coastal systems may be studied in detail to predict local, short-term changes or at a more aggregated level to indicate the net large scale, long-term effect. The whole spectrum of spatial and temporal scales needs to be considered for environmental impact studies. Usually this implies setting up a number of different models for different scales. Since the various models often use codes that have been independently developed by different researchers and include different formulations, it may be difficult to arrive at a consistent set of modeling results. This is one of the reasons why Deltares has taken on an effort to develop a consistent suite of model components that can be applied over a wide range of scales. The heart of this suite is formed by a flexible mesh flow component that supports mixed 1D-2D-3D domains, a equally flexible transport component with an expandable library of water quality and ecological processes, and a library of sediment transport and morphology routines that can be linked directly to the flow component or used as part of the process library. We will present the latest developments with a focus on the status of the sediment transport and morphology component for running consistent 1D, 2D and 3D models.

  10. NEW ACCELERATION METHODS

    SciTech Connect

    Sessler, A.M.

    1984-07-01

    But a glance at the Livingston chart, Fig. 1, of accelerator particle energy as a function of time shows that the energy has steadily, exponentially, increased. Equally significant is the fact that this increase is the envelope of diverse technologies. If one is to stay on, or even near, the Livingston curve in future years then new acceleration techniques need to be developed. What are the new acceleration methods? In these two lectures I would like to sketch some of these new ideas. I am well aware that they will probably not result in high energy accelerators within this or the next decade, but conversely, it is likely that these ideas will form the basis for the accelerators of the next century. Anyway, the ideas are stimulating and suffice to show that accelerator physicists are not just 'engineers', but genuine scientists deserving to be welcomed into the company of high energy physicists. I believe that outsiders will find this field surprisingly fertile and, certainly fun. To put it more personally, I very much enjoy working in this field and lecturing on it. There are a number of review articles which should be consulted for references to the original literature. In addition there are three books on the subject. Given this material, I feel free to not completely reference the material in the remainder of this article; consultation of the review articles and books will be adequate as an introduction to the literature for references abound (hundreds are given). At last, by way of introduction, I should like to quote from the end of Ref. 2 for I think the remarks made there are most germane. Remember that the talk was addressed to accelerator physicists: 'Finally, it is often said, I think by physicists who are not well-informed, that accelerator builders have used up their capital and now are bereft of ideas, and as a result, high energy physics will eventually--rather soon, in fact--come to a halt. After all, one can't build too many machines greater than

  11. SUPERDIFFUSIVE SHOCK ACCELERATION

    SciTech Connect

    Perri, S.; Zimbardo, G.

    2012-05-10

    The theory of diffusive shock acceleration is extended to the case of superdiffusive transport, i.e., when the mean square deviation grows proportionally to t{sup {alpha}}, with {alpha} > 1. Superdiffusion can be described by a statistical process called Levy random walk, in which the propagator is not a Gaussian but it exhibits power-law tails. By using the propagator appropriate for Levy random walk, it is found that the indices of energy spectra of particles are harder than those obtained where a normal diffusion is envisaged, with the spectral index decreasing with the increase of {alpha}. A new scaling for the acceleration time is also found, allowing substantially shorter times than in the case of normal diffusion. Within this framework we can explain a number of observations of flat spectra in various astrophysical and heliospheric contexts, for instance, for the Crab Nebula and the termination shock of the solar wind.

  12. Pulsed electromagnetic gas acceleration

    NASA Technical Reports Server (NTRS)

    Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

    1971-01-01

    Experimental data were combined with one-dimensional conservation relations to yield information on the energy deposition ratio in a parallel-plate accelerator, where the downstream flow was confined to a constant area channel. Approximately 70% of the total input power was detected in the exhaust flow, of which only about 20% appeared as directed kinetic energy, thus implying that a downstream expansion to convert chamber enthalpy into kinetic energy must be an important aspect of conventional high power MPD arcs. Spectroscopic experiments on a quasi-steady MPD argon accelerator verified the presence of A(III) and the absence of A(I), and indicated an azimuthal structure in the jet related to the mass injection locations. Measurements of pressure in the arc chamber and impact pressure in the exhaust jet using a piezocrystal backed by a Plexiglas rod were in good agreement with the electromagnetic thrust model.

  13. Review of ion accelerators

    SciTech Connect

    Alonso, J.

    1990-06-01

    The field of ion acceleration to higher energies has grown rapidly in the last years. Many new facilities as well as substantial upgrades of existing facilities have extended the mass and energy range of available beams. Perhaps more significant for the long-term development of the field has been the expansion in the applications of these beams, and the building of facilities dedicated to areas outside of nuclear physics. This review will cover many of these new developments. Emphasis will be placed on accelerators with final energies above 50 MeV/amu. Facilities such as superconducting cyclotrons and storage rings are adequately covered in other review papers, and so will not be covered here.

  14. Hypervelocity plate acceleration

    SciTech Connect

    Marsh, S.P.; Tan, T.H.

    1991-01-01

    Shock tubes have been used to accelerate 1.5-mm-thick stainless steel plates to high velocity while retaining their integrity. The fast shock tubes are 5.1-cm-diameter, 15.2-cm-long cylinders of PBX-9501 explosive containing a 1.1-cm-diameter cylindrical core of low-density polystyrene foam. The plates have been placed directly in contact with one face of the explosive system. Plane-wave detonation was initiated on the opposite face. A Mach disk was formed in the imploding styrofoam core, which provided the impulse required to accelerate the metal plate to high velocity. Parametric studies were made on this system to find the effect of varying plate metal, plate thickness, foam properties, and addition of a barrel. A maximum plate velocity of 9.0 km/s has been observed. 6 refs., 17 figs.

  15. Accelerators for Cancer Therapy

    DOE R&D Accomplishments Database

    Lennox, Arlene J.

    2000-05-30

    The vast majority of radiation treatments for cancerous tumors are given using electron linacs that provide both electrons and photons at several energies. Design and construction of these linacs are based on mature technology that is rapidly becoming more and more standardized and sophisticated. The use of hadrons such as neutrons, protons, alphas, or carbon, oxygen and neon ions is relatively new. Accelerators for hadron therapy are far from standardized, but the use of hadron therapy as an alternative to conventional radiation has led to significant improvements and refinements in conventional treatment techniques. This paper presents the rationale for radiation therapy, describes the accelerators used in conventional and hadron therapy, and outlines the issues that must still be resolved in the emerging field of hadron therapy.

  16. Commissioning the GTA accelerator

    SciTech Connect

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Brown, S.; Cole, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.; Johnson, K.F.; Kerstiens, D.; Little, C.; Lohsen, R.A.; Lloyd, S.; Lysenko, W.P.; Mottershead, C.T.; Neuschaefer, G.; Power, J.; Rusthoi, D.P.; Sandoval, D.P. Stevens, R.R. Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V. ); Connolly, R.; Weiss, R. (Gr

    1992-01-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth's magnetic field and travel in straight lines unless they enter the earth's atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H{sup -} beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor.

  17. Commissioning the GTA accelerator

    SciTech Connect

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Brown, S.; Cole, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.; Johnson, K.F.; Kerstiens, D.; Little, C.; Lohsen, R.A.; Lloyd, S.; Lysenko, W.P.; Mottershead, C.T.; Neuschaefer, G.; Power, J.; Rusthoi, D.P.; Sandoval, D.P. Stevens, R.R. Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V.; Connolly, R.; Weiss, R.; Saadatmand, K.

    1992-09-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth`s magnetic field and travel in straight lines unless they enter the earth`s atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H{sup -} beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor.

  18. Adaptive control for accelerators

    DOEpatents

    Eaton, Lawrie E.; Jachim, Stephen P.; Natter, Eckard F.

    1991-01-01

    An adaptive feedforward control loop is provided to stabilize accelerator beam loading of the radio frequency field in an accelerator cavity during successive pulses of the beam into the cavity. A digital signal processor enables an adaptive algorithm to generate a feedforward error correcting signal functionally determined by the feedback error obtained by a beam pulse loading the cavity after the previous correcting signal was applied to the cavity. Each cavity feedforward correcting signal is successively stored in the digital processor and modified by the feedback error resulting from its application to generate the next feedforward error correcting signal. A feedforward error correcting signal is generated by the digital processor in advance of the beam pulse to enable a composite correcting signal and the beam pulse to arrive concurrently at the cavity.

  19. Hardware Accelerated Simulated Radiography

    SciTech Connect

    Laney, D; Callahan, S; Max, N; Silva, C; Langer, S; Frank, R

    2005-04-12

    We present the application of hardware accelerated volume rendering algorithms to the simulation of radiographs as an aid to scientists designing experiments, validating simulation codes, and understanding experimental data. The techniques presented take advantage of 32 bit floating point texture capabilities to obtain validated solutions to the radiative transport equation for X-rays. An unsorted hexahedron projection algorithm is presented for curvilinear hexahedra that produces simulated radiographs in the absorption-only regime. A sorted tetrahedral projection algorithm is presented that simulates radiographs of emissive materials. We apply the tetrahedral projection algorithm to the simulation of experimental diagnostics for inertial confinement fusion experiments on a laser at the University of Rochester. We show that the hardware accelerated solution is faster than the current technique used by scientists.

  20. ATLAS accelerator laboratory report

    SciTech Connect

    Den Hartog, P.

    1986-01-01

    The operation of the ATLAS Accelerator is reported. Modifications are reported, including the installation of conductive tires for the Pelletron chain pulleys, installation of a new high frequency sweeper system at the entrance to the linac, and improvements to the rf drive ports of eight resonators to correct failures in the thermally conductive ceramic insulators. Progress is reported on the positive-ion injector upgrade for ATLAS. Also reported are building modifications and possible new uses for the tandem injector. (LEW)