WorldWideScience

Sample records for mode particles dominate

  1. Dominant modes via model error

    Science.gov (United States)

    Yousuff, A.; Breida, M.

    1992-01-01

    Obtaining a reduced model of a stable mechanical system with proportional damping is considered. Such systems can be conveniently represented in modal coordinates. Two popular schemes, the modal cost analysis and the balancing method, offer simple means of identifying dominant modes for retention in the reduced model. The dominance is measured via the modal costs in the case of modal cost analysis and via the singular values of the Gramian-product in the case of balancing. Though these measures do not exactly reflect the more appropriate model error, which is the H2 norm of the output-error between the full and the reduced models, they do lead to simple computations. Normally, the model error is computed after the reduced model is obtained, since it is believed that, in general, the model error cannot be easily computed a priori. The authors point out that the model error can also be calculated a priori, just as easily as the above measures. Hence, the model error itself can be used to determine the dominant modes. Moreover, the simplicity of the computations does not presume any special properties of the system, such as small damping, orthogonal symmetry, etc.

  2. Dominant Correlogram Based Particle Filter Tracking

    Institute of Scientific and Technical Information of China (English)

    MAO Yan-fen; SHI Peng-fei

    2005-01-01

    A novel dominant correlogram based particle filter was proposed for an object tracking in visual surveillance. Particle filter outperforms the Kalman filter in non-linear and non-Gaussian estimation problem. This paper proposed incorporating spatial information into visual feature, and yields a reliable likelihood description of the observation and prediction. A similarity-ratio is defined to evaluate the effectivity of different similarity measurements in weighing samples. The experimental results demonstrate the effective and robust performance compared with the histogram based tracking in traffic scenes.

  3. Apical-dominant particle swarm optimization

    Institute of Scientific and Technical Information of China (English)

    Zhihua Cui; Xingjuan Cai; Jianchao Zeng; Guoji Sun

    2008-01-01

    Particle swarm optimization (PSO) is a new stochastic population-based search methodology by simulating the animal social behaviors such as birds flocking and fish schooling.Many improvements have been proposed within the framework of this biological assumption.However,in this paper,the search pattern of PSO is used to model the branch growth process of natural plants.It provides a different poten-tial manner from artificial plant.To illustrate the effectiveness of this new model,apical dominance phenomenon is introduced to construct a novel variant by emphasizing the influence of the phototaxis.In this improvement,the population is divided into three different kinds of buds associated with their performances.Furthermore,a mutation strategy is applied to enhance the ability escaping from a local optimum.Sim-ulation results demonstrate good performance of the new method when solving high-dimensional multi-modal problems.

  4. Mode resolved density of atmospheric aerosol particles

    Directory of Open Access Journals (Sweden)

    P. Aalto

    2008-09-01

    Full Text Available In this study, we investigate the mode resolved density of ultrafine atmospheric particles measured in boreal forest environment. The method used here enables us to find the distinct density information for each mode in atmospheric fine particle population: the density values for nucleation, Aitken, and accumulation mode particles are presented. The experimental data was gained during 2 May 2005–19 May 2005 at the boreal forest measurement station "SMEAR II" in Hyytiälä, Southern Finland. The density values for accumulation mode varied from 1.1 to 2 g/cm3 (average 1.5 g/cm3 and for Aitken mode from 0.4 to 2 g/cm3 (average 0.97 g/cm3. As an overall trend during the two weeks campaign, the density value of Aitken mode was seen to gradually increase. With the present method, the time dependent behaviour of the particle density can be investigated in the time scale of 10 min. This allows us to follow the density evolution of the nucleation mode particles during the particle growth process following the nucleation burst. The density of nucleation mode particles decreased during the growth process. The density values for 15 nm particles were 1.2–1.5 g/cm3 and for grown 30 nm particles 0.5–1 g/cm3. These values are consistent with the present knowledge that the condensing species are semi-volatile organics, emitted from the boreal forest.

  5. Nonlinear saturation of trapped electron modes via perpendicular particle diffusion.

    Science.gov (United States)

    Merz, F; Jenko, F

    2008-01-25

    In magnetized fusion plasmas, trapped electron mode (TEM) turbulence constitutes, together with ion temperature gradient (ITG) turbulence, the dominant source of anomalous transport on ion scales. While ITG modes are known to saturate via nonlinear zonal flow generation, this mechanism is shown to be of little importance for TEM turbulence in the parameter regime explored here. Instead, a careful analysis of the statistical properties of the ExB nonlinearity in the context of gyrokinetic turbulence simulations reveals that perpendicular particle diffusion is the dominant saturation mechanism. These findings allow for the construction of a rather realistic quasilinear model of TEM induced transport.

  6. Dominant Mode Wave Impedance of Regular Polygonal Waveguides

    Directory of Open Access Journals (Sweden)

    Vyacheslav V. Komarov

    2014-01-01

    Full Text Available Polygonal metal waveguides are analyzed analytically and numerically. Classical equation for the wave impedance of arbitrary shaped waveguides is completed with approximate expression for the cutoff wavelength of the dominant mode. Proposed approach is tested with the help of 3D finite difference time domain models of microwave waveguides junctions. Obtained data are used for computer-aided design of microwave transition from coaxial line to cylindrical waveguide.

  7. Particle Distribution Modification by Low Amplitude Modes

    Energy Technology Data Exchange (ETDEWEB)

    White, R. B.; Gorelenkov, N.; Heidbrink, W. W.; Van Zeeland, M. A.

    2009-08-28

    Modification of a high energy particle distribution by a spectrum of low amplitude modes is investigated using a guiding center code. Only through resonance are modes effective in modifying the distribution. Diagnostics are used to illustrate the mode-particle interaction and to find which effects are relevant in producing significant resonance, including kinetic Poincare plots and plots showing those orbits with time averaged mode-particle energy transfer. Effects of pitch angle scattering and drag are studied, as well as plasma rotation and time dependence of the equilibrium and mode frequencies. A specific example of changes observed in a DIII-D deuterium beam distribution in the presence of low amplitude experimentally validated Toroidal Alfven (TAE) eigenmodes and Reversed Shear Alfven (RSAE) eigenmodes is examined in detail. Comparison with experimental data shows that multiple low amplitude modes can account for significant modification of high energy beam particle distributions. It is found that there is a stochastic threshold for beam profile modification, and that the experimental amplitudes are only slightly above this threshold.

  8. Partitioning of ice nucleating particles: Which modes matter?

    Science.gov (United States)

    Hande, Luke; Hoose, Corinna

    2017-04-01

    Ice particles in clouds have a large impact on cloud lifetime, precipitation amount, and cloud radiative properties through the indirect aerosol effect. Thus, correctly modelling ice formation processes is important for simulations preformed on all spatial and temporal scales. Ice forms on aerosol particles through several different mechanisms, namely deposition nucleation, immersion freezing, and contact freezing. However there is conflicting evidence as to which mode dominates, and the relative importance of the three heterogeneous ice nucleation mechanisms, as well as homogeneous nucleation, remains an open question. The environmental conditions, and hence the cloud type, have a large impact on determining which nucleation mode dominates. In order to understand this, simulations were performed with the COSMO-LES model, utilising state of the art parameterisations to describe the different nucleation mechanisms for several semi-idealised cloud types commonly occurring over central Europe. The cloud types investigated include a semi-idealised, and an idealised convective cloud, an orographic cloud, and a stratiform cloud. Results show that immersion and contact freezing dominate at warmer temperatures, and under most conditions, deposition nucleation plays only a minor role. In clouds where sufficiently high levels of water vapour are present at colder temperatures, deposition nucleation can play a role, however in general homogeneous nucleation dominates at colder temperatures. Since contact nucleation depends on the environmental relative humidity, enhancements in this nucleation mode can be seen in areas of dry air entrainment. The results indicate that ice microphysical processes are somewhat sensitve to the environmental conditions and therefore the cloud type.

  9. Magnetic normal modes in nano-particles

    Energy Technology Data Exchange (ETDEWEB)

    Grimsditch, M. [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States)]. E-mail: grimsditch@anl.gov; Giovannini, L. [Dipartimento di Fisica, Universita di Ferrara and Istituto Nazionale per la Fisica della Materia, Via del Paradiso 12, I-44100 Ferrara (Italy); Montoncello, F. [Dipartimento di Fisica, Universita di Ferrara and Istituto Nazionale per la Fisica della Materia, Via del Paradiso 12, I-44100 Ferrara (Italy); Nizzoli, F. [Dipartimento di Fisica, Universita di Ferrara and Istituto Nazionale per la Fisica della Materia, Via del Paradiso 12, I-44100 Ferrara (Italy); Leaf, G. [Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Kaper, H. [Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Karpeev, D. [Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2004-12-31

    We have recently developed two methods to calculate the magnetic normal modes of a magnetic nano-particle. One of the methods is based on a conventional micromagnetic approach in which the time evolution of the magnetization of each cell is monitored. After filtering in frequency domain, the magnetic normal modes can be reconstructed. The second method is based on solving the same micromagneitc system in a dynamical matrix formulation. The results of the two methods, applied to a rectangular parallelepiped of Fe, will be presented and compared.

  10. Perceptual Dominant Color Extraction by Multidimensional Particle Swarm Optimization

    Science.gov (United States)

    Kiranyaz, Serkan; Uhlmann (Eurasip Member), Stefan; Ince, Turker; Gabbouj, Moncef

    2010-12-01

    Color is the major source of information widely used in image analysis and content-based retrieval. Extracting dominant colors that are prominent in a visual scenery is of utmost importance since the human visual system primarily uses them for perception and similarity judgment. In this paper, we address dominant color extraction as a dynamic clustering problem and use techniques based on Particle Swarm Optimization (PSO) for finding optimal (number of) dominant colors in a given color space, distance metric and a proper validity index function. The first technique, so-called Multidimensional (MD) PSO can seek both positional and dimensional optima. Nevertheless, MD PSO is still susceptible to premature convergence due to lack of divergence. To address this problem we then apply Fractional Global Best Formation (FGBF) technique. In order to extract perceptually important colors and to further improve the discrimination factor for a better clustering performance, an efficient color distance metric, which uses a fuzzy model for computing color (dis-) similarities over HSV (or HSL) color space is proposed. The comparative evaluations against MPEG-7 dominant color descriptor show the superiority of the proposed technique.

  11. Perceptual Dominant Color Extraction by Multidimensional Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Moncef Gabbouj

    2009-01-01

    Full Text Available Color is the major source of information widely used in image analysis and content-based retrieval. Extracting dominant colors that are prominent in a visual scenery is of utmost importance since the human visual system primarily uses them for perception and similarity judgment. In this paper, we address dominant color extraction as a dynamic clustering problem and use techniques based on Particle Swarm Optimization (PSO for finding optimal (number of dominant colors in a given color space, distance metric and a proper validity index function. The first technique, so-called Multidimensional (MD PSO can seek both positional and dimensional optima. Nevertheless, MD PSO is still susceptible to premature convergence due to lack of divergence. To address this problem we then apply Fractional Global Best Formation (FGBF technique. In order to extract perceptually important colors and to further improve the discrimination factor for a better clustering performance, an efficient color distance metric, which uses a fuzzy model for computing color (dis- similarities over HSV (or HSL color space is proposed. The comparative evaluations against MPEG-7 dominant color descriptor show the superiority of the proposed technique.

  12. Tensor Modes Damping in Matter and Vacuum Dominated Era

    CERN Document Server

    Khodagholizadeh, Jafar; Asgari, Ali A

    2016-01-01

    The present paper has developed an integro-differential equation to propagate cosmological gravitation waves in matter-dominated era in accounting for the presence of free streaming neutrinos as a traceless transverse tensor part of the anisotropic stress tensor. Its focus is on short and long wavelengths of GWs that enter the horizon in matter-dominated era. Results show that the anisotropic stress reduces the squared amplitude by $ 0.03\\%$ for wavelengths, entering the horizon during matter-dominated phase. This reduction is less for those wavelengths that enter the horizon at $ \\Lambda $ dominated era in flat spacetime. All of the calculations have been done in closed spacetime and the results have been compared with the radiation-dominated case for both flat and closed spacetimes. Finally the paper investigates the effect of closed background on the amplitude of the gravitational waves.

  13. Investigation of dominant spin wave modes by domain walls collision

    Energy Technology Data Exchange (ETDEWEB)

    Ramu, M.; Purnama, I.; Goolaup, S.; Chandra Sekhar, M.; Lew, W. S., E-mail: wensiang@ntu.edu.sg [School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 (Singapore)

    2014-06-28

    Spin wave emission due to field-driven domain wall (DW) collision has been investigated numerically and analytically in permalloy nanowires. The spin wave modes generated are diagonally symmetric with respect to the collision point. The non-propagating mode has the highest amplitude along the middle of the width. The frequency of this mode is strongly correlated to the nanowire geometrical dimensions and is independent of the strength of applied field within the range of 0.1 mT to 1 mT. For nanowire with film thickness below 5 nm, a second spin wave harmonic mode is observed. The decay coefficient of the spin wave power suggests that the DWs in a memory device should be at least 300 nm apart for them to be free of interference from the spin waves.

  14. Trapped particle destabilization of the internal kink mode

    Energy Technology Data Exchange (ETDEWEB)

    White, R.B.; Chen, L.; Romanelli, F.; Hay, R.

    1984-06-01

    The internal kink mode is destabilized by trapped high energy particles, leading to a new branch of the internal kink dispersion relation with a real frequency near the average trapped particle precession frequency and a growth rate of the same magnitude. This trapped particle branch of the dispersion relation is investigated numerically for a variety of particle distributions. Mode growth rate and frequency are found as a function of plasma ..beta.., density, and trapped particle energy and distribution. The high energy trapped particle sources considered are neutral beam injection, ion cyclotron heating, and fusion alpha particles. Relevance for various plasma heating schemes is discussed.

  15. Particle compositions with a pre-selected cell internalization mode

    Science.gov (United States)

    Decuzzi, Paolo (Inventor); Ferrari, Mauro (Inventor)

    2012-01-01

    A method of formulating a particle composition having a pre-selected cell internalization mode involves selecting a target cell having surface receptors and obtaining particles that have i) surface moieties, that have an affinity for or are capable of binding to the surface receptors of the cell and ii) a preselected shape, where a surface distribution of the surface moieties on the particles and the shape of the particles are effective for the pre-selected cell internalization mode.

  16. Comparison between dominant NB and dominant IC heated ELMy H-mode discharges in JET

    NARCIS (Netherlands)

    Versloot, T. W.; Sartori, R.; Rimini, F.; de Vries, P. C.; Saibene, G.; Parail, V.; Beurskens, M. N. A.; Boboc, A.; Budny, R.; Crombe, K.; de la Luna, E.; Durodie, F.; Eich, T.; Giroud, C.; Kiptily, V.; Johnson, T.; Mantica, P.; Mayoral, M. L.; McDonald, D. C.; Monakhov, I.; Nave, M. F. F.; Voitsekhovitch, I.; Zastrow, K. D.

    2011-01-01

    The experiment described in this paper is aimed at characterization of ELMy H-mode discharges with varying momentum input, rotation, power deposition profiles and ion to electron heating ratio obtained by varying the proportion between ion cyclotron (IC) and neutral beam (NB) heating. The motivation

  17. Higher order microfibre modes for dielectric particle trapping and propulsion

    CERN Document Server

    Maimaiti, Aili; Sergides, Marios; Gusachenko, Ivan; Chormaic, Síle Nic

    2014-01-01

    Optical manipulation in the vicinity of optical micro- and nanofibres has shown potential across several fields in recent years, including microparticle control, and cold atom probing and trapping. To date, most work has focussed on propagation of the fundamental mode through the fibre. However, along the maximum mode intensity axis, higher order modes have a longer evanescent field extension and larger field amplitude at the fibre waist compared to the fundamental mode, opening up new possibilities for optical manipulation and particle trapping. In this work, we demonstrate a microfibre/optical tweezers compact system for trapping and propelling dielectric particles based on the excitation of the first group of higher order modes at the fibre waist. Single polystyrene particles were trapped and propelled in the evanescent fields of higher order and fundamental modes near the surface of microfibres. Speed enhancement of particle propulsion was observed for the higher order modes compared to the fundamental mo...

  18. From dressed particle to dressed mode in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Sanae-I. [Kyushu Univ., Research Inst. for Applied Mechanics, Kasuga, Fukuoka (Japan); Itoh, Kimitaka [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2002-05-01

    A theoretical method to analyze the strong turbulence in far-nonequilibrium plasma is discussed. In this approach, a test mode is treated being dressed with interactions with other modes. Nonlinear dispersion relation of the dressed mode and statistical treatment of turbulence is briefly explained. Analogue to the method of dressed particle, which has given Balescu-Lenard collision operator for inter-particle collisions, is mentioned. (author)

  19. G4beamline Particle Tracking in Matter Dominated Beam Lines

    Energy Technology Data Exchange (ETDEWEB)

    T.J. Roberts, K.B. Beard, S. Ahmed, D. Huang, D.M. Kaplan

    2011-03-01

    The G4beamline program is a useful and steadily improving tool to quickly and easily model beam lines and experimental equipment without user programming. It has both graphical and command-line user interfaces. Unlike most accelerator physics codes, it easily handles a wide range of materials and fields, being particularly well suited for the study of muon and neutrino facilities. As it is based on the Geant4 toolkit, G4beamline includes most of what is known about the interactions of particles with matter. We are continuing the development of G4beamline to facilitate its use by a larger set of beam line and accelerator developers. A major new feature is the calculation of space-charge effects. G4beamline is open source and freely available at http://g4beamline.muonsinc.com

  20. A quasi-stationary approach to particle concentration and distribution in gear oil for wear mode estimation

    DEFF Research Database (Denmark)

    Henneberg, Morten; Eriksen, René Lynge; Jørgensen, Bent

    2015-01-01

    Suspension of wear particles in gear oil with respect to the diversity of particle size combined with filter mechanisms has been analyzed. Coupling of wear modes from tribology is combined with particle size bins to show how a mathematical model can be expanded to include information gained from...... sensors that can segment particles into size bins. In order to establish boundary conditions for the model based on real data, a filtration test is included. Finally, the model is fitted to data from a gear in operation and differences between real data and the model are discussed. The findings show...... that particles less than 14 μm dominate the wear. Hence, it is concluded that abrasion dominate the wear, for the gear in operation, and it is concluded to be in quasi-stationary mode. The distribution of the particles is observed in conjunction with the particle quantity to determine a basis for normal...

  1. Investigation of dominant modes of monsoon ISO in the northwest and eastern Himalayan region

    Science.gov (United States)

    Mukherjee, Sandipan; Ballav, Srabanti; Soni, Sandeep; Kumar, Kireet; Kumar De, Utpal

    2016-08-01

    This study investigates the altitudinal variation of dominant modes of summer monsoon intra-seasonal oscillation (ISO) over the Northwest (NWH) and Eastern Himalayan (EH) region using (i) spatially scattered 133 number of station rainfall observations and (ii) latitudinal transect-wise (LT) rainfall variation, obtained from an observed interpolated gridded rainfall data for the period 1995-2004. The altitudinal variation of dominant modes of monsoon ISO were investigated by exploring the strong and weak phases of the principal components of 10-90 days bandpass rainfall data of June to September with respect to location specific station height. Investigation of frequency of days for light and moderate rainfall along with the occurrence of total seasonal rainy days has revealed existence of a rainfall maximum around 2100 m height for the NWH region. Similarly, the total seasonal rainy days of EH region was found to have maxima between 1100 and 1400 m height. Analyses of the spatially scattered station rainfall observation for the NWH region showed that the strong periods of ISO modes exist around 747.9 (±131.7) m and 2227.2 (±100.2) m heights. Over the EH region, the dominant modes of the monsoon ISO were found to be centred around 1200 m. Significant alterations of strong and weak phases of monsoon ISO as a response to altitudinal variation in the mountain surface were observed when latitudinal transect-wise variation of monsoon ISO modes were investigated.

  2. Particle production in reflection and transmission mode laser ablation: implications for laserspray ionization.

    Science.gov (United States)

    Musapelo, Thabiso; Murray, Kermit K

    2013-07-01

    Particles were ablated from laser desorption and inlet ionization matrix thin films with a UV laser in reflection and transmission geometries. Particle size distributions were measured with a combined scanning mobility particle sizer (SMPS) and aerodynamic particle sizer (APS) system that measured particles in the size range from 10 nm to 20 μm. The matrixes investigated were 2,5-dihydroxybenzoic acid (DHB), α-cyano-4-hydroxycinnamic acid (CHCA), sinapic acid (SA), 2,5-dihydroxy-acetophenone (DHAP), and 2-nitrophloroglucinol (NPG). Nanoparticles with average diameters between 20 and 120 nm were observed in both transmission and reflection geometry. The particle mass distribution was significantly different in reflection and transmission geometry. In reflection geometry, approximately equal mass was distributed between particles in the 20 to 450 nm range of diameters and particles in the 450 nm to 1.5 μm diameter range. In transmission mode, the particle mass distribution was dominated by large particles in the 2 to 20 μm diameter range. Ablation of inlet ionization matrices DHAP and NPG produced particles that were 3 to 4 times smaller compared with the other matrices. The results are consistent with ion formation by nanoparticle melting and breakup or melting and breakup of the large particles through contact with heated inlet surfaces. ᅟ

  3. Geiger-Mode Avalanche Photodiodes in Particle Detection

    OpenAIRE

    Vilella, E.; Alonso, O.; Trenado, J.; Vilà, A.; De Vos, M.; Garrido, L.; Diéguez, A.

    2012-01-01

    It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite sensitivity and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection remains still unexplored. In this contribution, we are going to expose the different steps that we have taken in order to prove the efficiency of Geiger mode avalanche photodiodes in the aforementioned field. In particula...

  4. Resuspension of Aerosol Particles from Evaporated Rain Drops to the Coarse Mode

    Science.gov (United States)

    Wang, H.; Easter, R. C.; Ganguly, D.; Singh, B.; Rasch, P. J.

    2015-12-01

    Precipitation scavenging (i.e., wet removal) has long been recognized as one of the major removal processes for tropospheric aerosol particles, and the dominant one for accumulation-mode size particles. When rain drops evaporate, the aerosol material contained in drops is resuspended, and this process has received much less attention. Unlike the resuspension from evaporated cloud droplets, the aerosol particles resuspended from evaporated rain drops have much larger sizes than most of the aerosol particles that acted as cloud condensation nuclei (CCN), became cloud borne, and then were collected by rain drops, because each rain drop generally collects thousands of cloud droplets. Here we present some aspects of this resuspension process obtained from modeling studies. First, we investigate some details of the process using a simple drop-size resolved model of raindrop evaporation in sub-saturated air below cloud base. Using these results, we then investigate different treatments of this process in a global aerosol and climate model that employs a modal aerosol representation. Compared to the model's original treatment of this process in which rain-borne aerosol is resuspended to the mode that it came from with its original size, the new treatment that resuspends to the coarse mode produces notable reductions in global CCN concentrations, as well as sulfate, black carbon, and organic aerosol mass, because the resuspended aerosol particles have much shorter lifetimes due to their larger sizes. Somewhat surprisingly, there are also notable reductions in coarse-mode sea salt and mineral dust burdens. These species are resuspended to the coarse mode in both the original and new treatments, but these resuspended particles are fewer in number and larger in size in the new treatment. This finding highlights some issues of the modal aerosol treatment for coarse mode particles.

  5. Conversion of the dominantly ideal perturbations into a tearing mode after a sawtooth crash

    Energy Technology Data Exchange (ETDEWEB)

    Igochine, V., E-mail: valentin.igochine@ipp.mpg.de; Gude, A.; Günter, S.; Lackner, K.; Yu, Q.; Barrera Orte, L.; McDermott, R. M. [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany); Bogomolov, A.; Classen, I. [FOM-Institute DIFFER, Dutch Institute for Fundamental Energy Research, 3430 BE Nieuwegein (Netherlands); Luhmann, N. C. [University of California at Davis, Davis, California 95616 (United States)

    2014-11-15

    Forced magnetic reconnection is a topic of common interest in astrophysics, space science, and magnetic fusion research. The tearing mode formation process after sawtooth crashes implies the existence of this type of magnetic reconnection and is investigated in great detail in the ASDEX Upgrade tokamak. The sawtooth crash provides a fast relaxation of the core plasma temperature and can trigger a tearing mode at a neighbouring resonant surface. It is demonstrated for the first time that the sawtooth crash leads to a dominantly ideal kink mode formation at the resonant surface immediately after the sawtooth crash. Local measurements show that this kink mode transforms into a tearing mode on a much longer timescale (10{sup −3}s−10{sup −2}s) than the sawtooth crash itself (10{sup −4}s). The ideal kink mode formed after the sawtooth crash provides the driving force for magnetic reconnection and its amplitude is one of the critical parameters for the length of the transition phase from a ideal into an resistive mode. Nonlinear two fluid MHD simulations confirm these observations.

  6. Enhancing dominant modes in nonstationary time series by means of the symbolic resonance analysis.

    Science.gov (United States)

    beim Graben, Peter; Drenhaus, Heiner; Brehm, Eva; Rhode, Bela; Saddy, Douglas; Frisch, Stefan

    2007-12-01

    We present the symbolic resonance analysis (SRA) as a viable method for addressing the problem of enhancing a weakly dominant mode in a mixture of impulse responses obtained from a nonlinear dynamical system. We demonstrate this using results from a numerical simulation with Duffing oscillators in different domains of their parameter space, and by analyzing event-related brain potentials (ERPs) from a language processing experiment in German as a representative application. In this paradigm, the averaged ERPs exhibit an N400 followed by a sentence final negativity. Contemporary sentence processing models predict a late positivity (P600) as well. We show that the SRA is able to unveil the P600 evoked by the critical stimuli as a weakly dominant mode from the covering sentence final negativity.

  7. Enhancing dominant modes in nonstationary time series by means of the symbolic resonance analysis

    Science.gov (United States)

    beim Graben, Peter; Drenhaus, Heiner; Brehm, Eva; Rhode, Bela; Saddy, Douglas; Frisch, Stefan

    2007-12-01

    We present the symbolic resonance analysis (SRA) as a viable method for addressing the problem of enhancing a weakly dominant mode in a mixture of impulse responses obtained from a nonlinear dynamical system. We demonstrate this using results from a numerical simulation with Duffing oscillators in different domains of their parameter space, and by analyzing event-related brain potentials (ERPs) from a language processing experiment in German as a representative application. In this paradigm, the averaged ERPs exhibit an N400 followed by a sentence final negativity. Contemporary sentence processing models predict a late positivity (P600) as well. We show that the SRA is able to unveil the P600 evoked by the critical stimuli as a weakly dominant mode from the covering sentence final negativity.

  8. Identification of dominant flow structures in rapidly rotating convection of liquid metals using Dynamic Mode Decomposition

    Science.gov (United States)

    Horn, S.; Schmid, P. J.; Aurnou, J. M.

    2016-12-01

    The Earth's metal core acts as a dynamo whose efficiency in generating and maintaining the magnetic field is essentially determined by the rotation rate and the convective motions occurring in its outer liquid part. For the description of the primary physics in the outer core the idealized system of rotating Rayleigh-Bénard convection is often invoked, with the majority of studies considering only working fluids with Prandtl numbers of Pr ≳ 1. However, liquid metals are characterized by distinctly smaller Prandtl numbers which in turn result in an inherently different type of convection. Here, we will present results from direct numerical simulations of rapidly rotating convection in a fluid with Pr ≈ 0.025 in cylindrical containers and Ekman numbers as low as 5 × 10-6. In this system, the Coriolis force is the source of two types of inertial modes, the so-called wall modes, that also exist at moderate Prandtl numbers, and cylinder-filling oscillatory modes, that are a unique feature of small Prandtl number convection. The obtained flow fields were analyzed using the Dynamic Mode Decomposition (DMD). This technique allows to extract and identify the structures that govern the dynamics of the system as well as their corresponding frequencies. We have investigated both the regime where the flow is purely oscillatory and the regime where wall modes and oscillatory modes co-exist. In the purely oscillatory regime, high and low frequency oscillatory modes characterize the flow. When both types of modes are present, the DMD reveals that the wall-attached modes dominate the flow dynamics. They precess with a relatively low frequency in retrograde direction. Nonetheless, also in this case, high frequency oscillations have a significant contribution.

  9. Geiger-Mode Avalanche Photodiodes in Particle Detection

    CERN Document Server

    Vilella, E; Trenado, J; Vila, A; Vos, M; Garrido, L; Dieguez, A

    2012-01-01

    It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite sensitivity and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection remains still unexplored. In this contribution, we are going to expose the different steps that we have taken in order to prove the efficiency of Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present an array of pixels of 1mmx1mm fabricated with a standard CMOS technology for characterization in a test beam.

  10. The Dominant Synoptic-Scale Modes of North American Monsoon Precipitation

    Science.gov (United States)

    Serra, Y. L.; Seastrand, S.; Castro, C. L.; Ritchie, E.

    2014-12-01

    In this study we explore the mechanisms of synoptic rainfall variability using observations from the Tropical Rainfall Measuring Mission satellite. While previously shown to have an important impact on North American monsoon rainfall, tropical cyclones are excluded from this analysis, in order to focus on more frequent synoptic disturbances within the region. A rotated empirical orthogonal function analysis of North American monsoon rainfall for June through September 2002-2009 suggests low-level tropical disturbances contribute to the leading two modes of precipitation variability within this region. The low-level disturbances result in gulf surges, or low-level surges of moisture up the Gulf of California, and provide a key low-level moisture source to facilitate development of organized convection. In the first mode the low-level trough brings precipitation to lower elevations along the western slopes of the Sierra Madre Occidental south of Hermosillo, Mexico and over the southern Baja Peninsula. In the second mode the low-level trough interacts with an upper-level inverted trough enhancing precipitation into the southwestern United States and northwest Mexico. In particular, the upper-level trough contributes to the easterly-northeasterly shear across the region, favoring mesoscale convective organization and enhanced deep convection over the Sierra Madre Occidental and higher elevations in southeast Arizona. The EOF methodology offers an objective approach for determining the dominant modes of precipitation for the monsoon region useful for identifying past and monitoring future low-frequency impacts on these modes.

  11. Quantum breathing mode of interacting particles in harmonic traps

    Science.gov (United States)

    Bauch, Sebastian; Hochstuhl, David; Balzer, Karsten; Bonitz, Michael

    2010-04-01

    The breathing mode - the uniform radial expansion and contraction of a system of interacting particles - is analyzed. Extending our previous work [Bauch et al 2009 Phys. Rev. B. 80 054515] we present a systematic analysis of the breathing mode for fermions with an inverse power law interaction potential w(r) ~ r-dwith d = 1,2,3 in the whole range of coupling parameters. The results thus cover the range from the ideal "gas" to the Wigner crystal-like state. In addition to exact results for two particles obtained from a solution of the time-dependent Schrödinger equation we present results for N = 4,6 from multiconfiguration time-dependent Hartree-Fock simulations.

  12. Rainfall mechanisms for the dominant rainfall mode over Zimbabwe relative to ENSO and/or IODZM.

    Science.gov (United States)

    Manatsa, Desmond; Mukwada, Geoffrey

    2012-01-01

    Zimbabwe's homogeneous precipitation regions are investigated by means of principal component analysis (PCA) with regard to the underlying processes related to ENSO and/or Indian Ocean Dipole zonal mode (IODZM). Station standardized precipitation index rather than direct rainfall values represent the data matrix used in the PCA. The results indicate that the country's rainfall is highly homogeneous and is dominantly described by the first principal mode (PC1). This leading PC can be used to represent the major rainfall patterns affecting the country, both spatially and temporarily. The current practice of subdividing the country into the two seasonal rainfall forecast zones becomes irrelevant. Partial correlation analysis shows that PC1 is linked more to the IODZM than to the traditional ENSO which predominantly demonstrates insignificant association with PC1. The pure IODZM composite is linked to the most intense rainfall suppression mechanisms, while the pure El Niño composite is linked to rainfall enhancing mechanisms.

  13. False Blister Beetles and the Expansion of Gymnosperm-Insect Pollination Modes before Angiosperm Dominance.

    Science.gov (United States)

    Peris, David; Pérez-de la Fuente, Ricardo; Peñalver, Enrique; Delclòs, Xavier; Barrón, Eduardo; Labandeira, Conrad C

    2017-02-26

    During the mid-Cretaceous, angiosperms diversified from several nondiverse lineages to their current global domination [1], replacing earlier gymnosperm lineages [2]. Several hypotheses explain this extensive radiation [3], one of which involves proliferation of insect pollinator associations in the transition from gymnosperm to angiosperm dominance. However, most evidence supports gymnosperm-insect pollinator associations, buttressed by direct evidence of pollen on insect bodies, currently established for four groups: Thysanoptera (thrips), Neuroptera (lacewings), Diptera (flies), and now Coleoptera (beetles). Each group represents a distinctive pollination mode linked to a unique mouthpart type and feeding guild [4-9]. Extensive indirect evidence, based on specialized head and mouthpart morphology, is present for one of these pollinator types, the long-proboscid pollination mode [10], representing minimally ten family-level lineages of Neuroptera, Mecoptera (scorpionflies), and Diptera [8, 10, 11]. A recurring feature uniting these pollinator modes is host associations with ginkgoalean, cycad, conifer, and bennettitalean gymnosperms. Pollinator lineages bearing these pollination modes were categorized into four evolutionary cohorts during the 35-million-year-long angiosperm radiation, each defined by its host-plant associations (gymnosperm or angiosperm) and evolutionary pattern (extinction, continuation, or origination) during this interval [12]. Here, we provide the first direct evidence for one cohort, exemplified by the beetle Darwinylus marcosi, family Oedemeridae (false blister beetles), that had an earlier gymnosperm (most likely cycad) host association, later transitioning onto angiosperms [13]. This association constitutes one of four patterns explaining the plateau of family-level plant lineages generally and pollinating insects specifically during the mid-Cretaceous angiosperm radiation [12].

  14. Nonlinear simulations of particle source effects on edge localized mode

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.; Tang, C. J. [College of Physical Science and Technology, Sichuan University, Chengdu 610065 (China); Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Chen, S. Y., E-mail: sychen531@163.com [College of Physical Science and Technology, Sichuan University, Chengdu 610065 (China); Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Southwestern Institute of Physics, Chengdu 610041 (China); Wang, Z. H. [Southwestern Institute of Physics, Chengdu 610041 (China)

    2015-12-15

    The effects of particle source (PS) with different intensities and located positions on Edge Localized Mode (ELM) are systematically studied with BOUT++ code. The results show the ELM size strongly decreases with increasing the PS intensity once the PS is located in the middle or bottom of the pedestal. The effects of PS on ELM depend on the located position of PS. When it is located at the top of the pedestal, peeling-ballooning (P-B) modes can extract more free energy from the pressure gradient and grow up to be a large filament at the initial crash phase and the broadening of mode spectrum can be suppressed by PS, which leads to more energy loss. When it is located in the middle or bottom of the pedestal, the extraction of free energy by P-B modes can be suppressed, and a small filament is generated. During the turbulence transport phase, the broader mode spectrum suppresses the turbulence transport when PS is located in the middle, while the zonal flow plays an important role in damping the turbulence transport when PS is located at the bottom.

  15. On the contribution of Aitken mode particles to cloud droplet populations at continental background areas – a parametric sensitivity study

    Directory of Open Access Journals (Sweden)

    V.-M. Kerminen

    2007-05-01

    Full Text Available Aitken mode particles are potentially an important source of cloud droplets in continental background areas. In order to find out which physico-chemical properties of Aitken mode particles are most important regarding their cloud-nucleating ability, we applied a global sensitivity method to an adiabatic air parcel model simulating the number of cloud droplets formed on Aitken mode particles, CD2. The technique propagates uncertainties in the parameters describing the properties of Aitken mode to CD2. The results show that if the Aitken mode particles do not contain molecules that are able to reduce the particle surface tension more than 30% and/or decrease the mass accommodation coefficient of water, α, below 10−2, the chemical composition and modal properties may have roughly an equal importance at low updraft velocities characterized by maximum supersaturations <0.1%. For larger updraft velocities, however, the particle size distribution is clearly more important than the chemical composition. In general, CD2 exhibits largest sensitivity to the particle number concentration, followed by the particle size. Also the shape of the particle mode, characterized by the geometric standard deviation (GSD, can be as important as the mode mean size at low updraft velocities. Finally, the performed sensitivity analysis revealed also that the chemistry may dominate the total sensitivity of CD2 to the considered parameters if: 1 the value of α varies at least one order of magnitude more than what is expected for pure water surfaces (10−2–1, or 2 the particle surface tension varies more than roughly 30% under conditions close to reaching supersaturation.

  16. Gyrokinetic δ particle simulation of trapped electron mode driven turbulence

    Science.gov (United States)

    Lang, Jianying

    2007-11-01

    Turbulent transport driven by collisionless trapped electron modes (CTEM) is systematically studied using gyrokinetic delta-f particle-in-cell simulation. Scaling with local plasma parameters, including density gradient, electron temperature gradient, magnetic shear, temperature ratio and aspect ratio, is investigated. Simulation results are compared with previous simulations and theoretical predictions. Nonlinearly the transport level increases with increasing magnetic shear. We explain the nonlinear magnetic shear scaling by differences in the radial correlation lengths caused by toroidal coupling. The turbulence is more radially elongated at higher magnetic shear compared with low magnetic shear. We show that the suppression effect of zonal flow on CTEM transport depends on both the electron temperature gradient and the electron to ion temperature ratio. This helps explain the previous contradictory conclusions on the importance of zonal flows in different parameter regimes.ootnotetextT. Dannert, F. Jenko, Phys. Plasmas 12, 072309 (2005); D. Ernst, et al., Phys. Plasmas 11, 2637 (2004). Zonal flow suppression is consistent with the rate of EXB shearing from the ambient turbulence as well as the radial broadening of the spectra. Strong geodesic acoustic modes (GAMs) are generated along with zonal flows and the frequency of the GAMs agrees well with kinetic theory.ootnotetextT. Watari, et al., Phys. Plasmas 13, 062504 (2006). We further explore the nonlinear saturation mechanism when the zonal flows are not important. We find that when only a single toroidal mode (and its conjugate) is kept, reasonable nonlinear saturation is obtained. Investigating a range of n, modes with larger mode number n saturate at a higher level relative to lower n modes, indicating a turbulent inverse cascade process.

  17. Kinetic freeze-out, particle spectra and harmonic flow coefficients from mode-by-mode hydrodynamics

    CERN Document Server

    Floerchinger, Stefan

    2014-01-01

    The kinetic freeze-out for the hydrodynamical description of relativistic heavy ion collisions is discussed using a background-fluctuation splitting of the hydrodynamical fields. For a single event, the particle spectrum, or its logarithm, can be written as the sum of background part that is symmetric with respect to azimuthal rotations and longitudinal boosts and a part containing the contribution of fluctuations or deviations from the background. Using a complete orthonormal basis to characterize the initial state allows one to write the double differential harmonic flow coefficients determined by the two-particle correlation method as matrix expressions involving the initial fluid correlations. We discuss the use of these expressions for a mode-by-mode analysis of fluctuating initial conditions in heavy ion collisions.

  18. ON THE DISTRIBUTION OF PARTICLE ACCELERATION SITES IN PLASMOID-DOMINATED RELATIVISTIC MAGNETIC RECONNECTION

    Energy Technology Data Exchange (ETDEWEB)

    Nalewajko, Krzysztof [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road M/S 29, Menlo Park, CA 94025 (United States); Uzdensky, Dmitri A.; Werner, Gregory R. [Center for Integrated Plasma Studies, Physics Department, University of Colorado, UCB 390, Boulder, CO 80309-0390 (United States); Cerutti, Benoit [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Begelman, Mitchell C., E-mail: knalew@stanford.edu [JILA, University of Colorado and National Institute of Standards and Technology, 440 UCB, Boulder, CO 80309 (United States)

    2015-12-20

    We investigate the distribution of particle acceleration sites, independently of the actual acceleration mechanism, during plasmoid-dominated, relativistic collisionless magnetic reconnection by analyzing the results of a particle-in-cell numerical simulation. The simulation is initiated with Harris-type current layers in pair plasma with no guide magnetic field, negligible radiative losses, no initial perturbation, and using periodic boundary conditions. We find that the plasmoids develop a robust internal structure, with colder dense cores and hotter outer shells, that is recovered after each plasmoid merger on a dynamical timescale. We use spacetime diagrams of the reconnection layers to probe the evolution of plasmoids, and in this context we investigate the individual particle histories for a representative sample of energetic electrons. We distinguish three classes of particle acceleration sites associated with (1) magnetic X-points, (2) regions between merging plasmoids, and (3) the trailing edges of accelerating plasmoids. We evaluate the contribution of each class of acceleration sites to the final energy distribution of energetic electrons: magnetic X-points dominate at moderate energies, and the regions between merging plasmoids dominate at higher energies. We also identify the dominant acceleration scenarios, in order of decreasing importance: (1) single acceleration between merging plasmoids, (2) single acceleration at a magnetic X-point, and (3) acceleration at a magnetic X-point followed by acceleration in a plasmoid. Particle acceleration is absent only in the vicinity of stationary plasmoids. The effect of magnetic mirrors due to plasmoid contraction does not appear to be significant in relativistic reconnection.

  19. Particle transport in density gradient driven TE mode turbulence

    CERN Document Server

    Skyman, Andreas; Strand, P I

    2011-01-01

    The turbulent transport of main ion and trace impurities in a tokamak device in the presence of steep electron density gradients has been studied. The parameters are chosen for trapped electron (TE) mode turbulence, driven primarily by steep electron density gradients relevant to H-mode physics, but with a transition to temperature gradient driven turbulence as the density gradient flattens. Results obtained through non-linear (NL) and quasilinear (QL) gyrokinetic simulations using the GENE code are compared with results obtained from a fluid model. Main ion and impurity transport is studied by examining the balance of convective and diffusive transport, as quantified by the density gradient corresponding to zero particle flux (peaking factor). Scalings are obtained for the impurity peaking with the background electron density gradient and the impurity charge number. It is shown that the impurity peaking factor is weakly dependent on impurity charge and significantly smaller than the driving electron density ...

  20. Multi-Objective Bidding Strategy for Genco Using Non-Dominated Sorting Particle Swarm Optimization

    Science.gov (United States)

    Saksinchai, Apinat; Boonchuay, Chanwit; Ongsakul, Weerakorn

    2010-06-01

    This paper proposes a multi-objective bidding strategy for a generation company (GenCo) in uniform price spot market using non-dominated sorting particle swarm optimization (NSPSO). Instead of using a tradeoff technique, NSPSO is introduced to solve the multi-objective strategic bidding problem considering expected profit maximization and risk (profit variation) minimization. Monte Carlo simulation is employed to simulate rivals' bidding behavior. Test results indicate that the proposed approach can provide the efficient non-dominated solution front effectively. In addition, it can be used as a decision making tool for a GenCo compromising between expected profit and price risk in spot market.

  1. New modes of particle accelerations techniques and sources. Formal report

    Energy Technology Data Exchange (ETDEWEB)

    Parsa, Z. [ed.

    1996-12-31

    This Report includes copies of transparencies and notes from the presentations made at the Symposium on New Modes of Particle Accelerations - Techniques and Sources, August 19-23, 1996 at the Institute for Theoretical Physics, University of California, Santa Barbara California, that was made available by the authors. Editing, reduction and changes to the authors contributions were made only to fulfill the printing and publication requirements. We would like to take this opportunity and thank the speakers for their informative presentations and for providing copies of their transparencies and notes for inclusion in this Report.

  2. Interaction of Charged Particles with Ultra Strong Electromagnetic Waves in the Radiation Dominant Regime

    Science.gov (United States)

    Bulanov, S. V.; Esirkepov, T. Zh.; Koga, J.; Tajima, T.

    2004-10-01

    The plasma particle interaction with a relativistically intense electromagnetic wave under the conditions when the radiation reaction effects are dominant is considered. We analyze the radiation damping effects on the electron motion inside the circularly polarized planar wave and inside a subcycle crossed-field electromagnetic pulse. We consider the ion acceleration due to the radiation pressure action on a thin plasma slab. The results of 2D and 3D PIC simulations are presented.

  3. Rainfall Mechanisms for the Dominant Rainfall Mode over Zimbabwe Relative to ENSO and/or IODZM

    Directory of Open Access Journals (Sweden)

    Desmond Manatsa

    2012-01-01

    Full Text Available Zimbabwe’s homogeneous precipitation regions are investigated by means of principal component analysis (PCA with regard to the underlying processes related to ENSO and/or Indian Ocean Dipole zonal mode (IODZM. Station standardized precipitation index rather than direct rainfall values represent the data matrix used in the PCA. The results indicate that the country’s rainfall is highly homogeneous and is dominantly described by the first principal mode (PC1. This leading PC can be used to represent the major rainfall patterns affecting the country, both spatially and temporarily. The current practice of subdividing the country into the two seasonal rainfall forecast zones becomes irrelevant. Partial correlation analysis shows that PC1 is linked more to the IODZM than to the traditional ENSO which predominantly demonstrates insignificant association with PC1. The pure IODZM composite is linked to the most intense rainfall suppression mechanisms, while the pure El Niño composite is linked to rainfall enhancing mechanisms.

  4. Particle and thermal transport due to drift resistive ballooning modes

    Science.gov (United States)

    Goldstein, T.; Rafiq, T.; Kritz, A. H.; Bateman, G.; Pankin, A. Y.

    2009-11-01

    The ion-temperature-gradient and trapped electron modes are primary candidates for producing the turbulence that drives anomalous transport in the core of magnetically confined plasmas. The situation at the edge is different. Since the edge plasma is influenced strongly by collisions, it is expected that resistive ballooning modes (RBMs) are an important driver of turbulence in the edge region. In this work, a new advanced RBM model [1] is tested as a function of plasma parameters. In this model, the eigenvalues and eigenvectors are used together with a quasi-linear mixing length estimate to determine fluxes and diffusivities. Particle and thermal transport coefficients are investigated in systematic scans over plasma density, density gradient, electron and ion temperature gradients, magnetic q, collisions, magnetic shear, finite Larmor radius effects, and pressure gradient. In the low temperature plasma region, it is found that RBM diffusivities increase with increasing density gradient, magnetic q, and collisionality.[4pt] [1] T. Rafiq, et al, poster at this APS meeting

  5. Particle Acceleration and Plasma Dynamics during Magnetic Reconnection in the Magnetically-dominated Regime

    CERN Document Server

    Guo, Fan; Daughton, William; Li, Hui

    2015-01-01

    Magnetic reconnection is thought to be the driver for many explosive phenomena in the universe. The energy release and particle acceleration during reconnection have been proposed as a mechanism for producing high-energy emissions and cosmic rays. We carry out two- and three-dimensional kinetic simulations to investigate relativistic magnetic reconnection and the associated particle acceleration. The simulations focus on electron-positron plasmas starting with a magnetically dominated, force-free current sheet ($\\sigma \\equiv B^2/(4\\pi n_e m_e c^2) \\gg 1$). For this limit, we demonstrate that relativistic reconnection is highly efficient at accelerating particles through a first-order Fermi process accomplished by the curvature drift of particles along the electric field induced by the relativistic flows. This mechanism gives rise to the formation of hard power-law spectra $f \\propto (\\gamma-1)^{-p}$ and approaches $p = 1$ for sufficiently large $\\sigma$ and system size. Eventually most of the available magne...

  6. Analytical expressions for chatter analysis in milling operations with one dominant mode

    Science.gov (United States)

    Iglesias, A.; Munoa, J.; Ciurana, J.; Dombovari, Z.; Stepan, G.

    2016-08-01

    In milling, an accurate prediction of chatter is still one of the most complex problems in the field. The presence of these self-excited vibrations can spoil the surface of the part and can also cause a large reduction in tool life. The stability diagrams provide a practical selection of the optimum cutting conditions determined either by time domain or frequency domain based methods. Applying these methods parametric or parameter traced representations of the linear stability limits can be achieved by solving the corresponding eigenvalue problems. In this work, new analytical formulae are proposed related to the parameter domains of both Hopf and period doubling type stability boundaries emerging in the regenerative mechanical model of time periodical milling processes. These formulae are useful to enrich and speed up the currently used numerical methods. Also, the destabilization mechanism of double period chatter is explained, creating an analogy with the chatter related to the Hopf bifurcation, considering one dominant mode and using concepts established by the Pioneers of chatter research.

  7. Modes of interaction between individuals dominate the topologies of real world networks.

    Directory of Open Access Journals (Sweden)

    Insuk Lee

    Full Text Available We find that the topologies of real world networks, such as those formed within human societies, by the Internet, or among cellular proteins, are dominated by the mode of the interactions considered among the individuals. Specifically, a major dichotomy in previously studied networks arises from modeling networks in terms of pairwise versus group tasks. The former often intrinsically give rise to scale-free, disassortative, hierarchical networks, whereas the latter often give rise to single- or broad-scale, assortative, nonhierarchical networks. These dependencies explain contrasting observations among previous topological analyses of real world complex systems. We also observe this trend in systems with natural hierarchies, in which alternate representations of the same networks, but which capture different levels of the hierarchy, manifest these signature topological differences. For example, in both the Internet and cellular proteomes, networks of lower-level system components (routers within domains or proteins within biological processes are assortative and nonhierarchical, whereas networks of upper-level system components (internet domains or biological processes are disassortative and hierarchical. Our results demonstrate that network topologies of complex systems must be interpreted in light of their hierarchical natures and interaction types.

  8. Modes of interaction between individuals dominate the topologies of real world networks.

    Science.gov (United States)

    Lee, Insuk; Kim, Eiru; Marcotte, Edward M

    2015-01-01

    We find that the topologies of real world networks, such as those formed within human societies, by the Internet, or among cellular proteins, are dominated by the mode of the interactions considered among the individuals. Specifically, a major dichotomy in previously studied networks arises from modeling networks in terms of pairwise versus group tasks. The former often intrinsically give rise to scale-free, disassortative, hierarchical networks, whereas the latter often give rise to single- or broad-scale, assortative, nonhierarchical networks. These dependencies explain contrasting observations among previous topological analyses of real world complex systems. We also observe this trend in systems with natural hierarchies, in which alternate representations of the same networks, but which capture different levels of the hierarchy, manifest these signature topological differences. For example, in both the Internet and cellular proteomes, networks of lower-level system components (routers within domains or proteins within biological processes) are assortative and nonhierarchical, whereas networks of upper-level system components (internet domains or biological processes) are disassortative and hierarchical. Our results demonstrate that network topologies of complex systems must be interpreted in light of their hierarchical natures and interaction types.

  9. Transport of super-thermal particles and their effect on the stability of global modes in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Schneller, Mirjam Simone

    2013-08-02

    In thermonuclear plasmas, a population of super-thermal particles generated by external heating methods or fusion reactions can lead to the excitation of global instabilities. The transport processes due to nonlinear wave-particle interactions and the consequential particle losses reduce the plasma heating and the efficiency of the fusion reaction rate. Furthermore, these energetic or fast particles may cause severe damages to the wall of the device. This thesis addresses the resonance mechanisms between these energetic particles and global MHD and kinetic MHD waves, employing the hybrid code HAGIS. A systematic investigation of energetic particles resonant with multiple modes (double-resonance) is presented for the first time. The double-resonant mode coupling is modeled for waves with different frequencies in various overlapping scenarios. It is found that, depending on the radial mode distance, double-resonance is able to significantly enhance, both the growth rates and the saturation amplitudes. Small radial mode distances, however can lead to strong nonlinear mode stabilization of a linear dominant mode. For the first time, simulations of experimental conditions in the ASDEX Upgrade fusion device are performed for different plasma equilibria (particularly for different q profiles). An understanding of fast particle behavior for non-monotonic q profiles is important for the development of advanced fusion scenarios. The numerical tool is the extended version of the HAGIS code, which computes the particle motion in the vacuum region between vessel wall in addition to the internal plasma volume. For this thesis, a consistent fast particle distribution function was implemented, to represent the fast particle population generated by the particular heating method (ICRH). Furthermore, HAGIS was extended to use more realistic eigenfunctions, calculated by the gyrokinetic eigenvalue solver LIGKA. One important aim of these simulations is to allow fast ion loss

  10. A method for detecting the presence of organic fraction in nucleation mode sized particles

    OpenAIRE

    Vaattovaara, P.; Räsänen, M.; Kühn, T.; Joutsensaari, J.; Laaksonen, A.

    2005-01-01

    International audience; New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d

  11. Inertially confined fusion plasmas dominated by alpha-particle self-heating

    Science.gov (United States)

    Hurricane, O. A.; Callahan, D. A.; Casey, D. T.; Dewald, E. L.; Dittrich, T. R.; Döppner, T.; Haan, S.; Hinkel, D. E.; Berzak Hopkins, L. F.; Jones, O.; Kritcher, A. L.; Le Pape, S.; Ma, T.; Macphee, A. G.; Milovich, J. L.; Moody, J.; Pak, A.; Park, H.-S.; Patel, P. K.; Ralph, J. E.; Robey, H. F.; Ross, J. S.; Salmonson, J. D.; Spears, B. K.; Springer, P. T.; Tommasini, R.; Albert, F.; Benedetti, L. R.; Bionta, R.; Bond, E.; Bradley, D. K.; Caggiano, J.; Celliers, P. M.; Cerjan, C.; Church, J. A.; Dylla-Spears, R.; Edgell, D.; Edwards, M. J.; Fittinghoff, D.; Barrios Garcia, M. A.; Hamza, A.; Hatarik, R.; Herrmann, H.; Hohenberger, M.; Hoover, D.; Kline, J. L.; Kyrala, G.; Kozioziemski, B.; Grim, G.; Field, J. E.; Frenje, J.; Izumi, N.; Gatu Johnson, M.; Khan, S. F.; Knauer, J.; Kohut, T.; Landen, O.; Merrill, F.; Michel, P.; Moore, A.; Nagel, S. R.; Nikroo, A.; Parham, T.; Rygg, R. R.; Sayre, D.; Schneider, M.; Shaughnessy, D.; Strozzi, D.; Town, R. P. J.; Turnbull, D.; Volegov, P.; Wan, A.; Widmann, K.; Wilde, C.; Yeamans, C.

    2016-08-01

    Alpha-particle self-heating, the process of deuterium-tritium fusion reaction products depositing their kinetic energy locally within a fusion reaction region and thus increasing the temperature in the reacting region, is essential for achieving ignition in a fusion system. Here, we report new inertial confinement fusion experiments where the alpha-particle heating of the plasma is dominant with the fusion yield produced exceeding the fusion yield from the work done on the fuel (pressure times volume change) by a factor of two or more. These experiments have achieved the highest yield (26 +/- 0.5 kJ) and stagnation pressures (≍220 +/- 40 Gbar) of any facility-based inertial confinement fusion experiments, although they are still short of the pressures required for ignition on the National Ignition Facility (~300-400 Gbar). These experiments put us in a new part of parameter space that has not been extensively studied so far because it lies between the no-alpha-particle-deposition regime and ignition.

  12. Fission modes in charged-particle induced fission

    Energy Technology Data Exchange (ETDEWEB)

    Matthies, A.; Kotte, R.; Seidel, W.; Stary, F.; Wohlfarth, D. (Zentralinstitut fuer Kernforschung, Rossendorf bei Dresden (German Democratic Republic))

    1990-12-01

    The population of the three fission modes predicted by Brosa's multi-channel fission model for the uranium region was studied in different fissioning systems. They were produced bombarding {sup 232}Th and {sup 238}U targets by light charged particles with energies slightly above the Coulomb barrier. Though the maximum excitation energy of the compound nucleus amounted to about 22 MeV, the influences of various spherical and deformed nuclear shells on the mass and total kinetic energy distributions of fission fragments are still pronounced. The larger variances of the total kinetic energy distributions compared to those of thermal neutron induced fission were explained by temperature dependent fluctuations of the amount and velocity of alteration of the scission point elongation of the fissioning system. From the ratio of these variances the portion of the potential energy dissipated among intrinsic degrees of freedom before scission was deduced for the different fission channels. It was found that the excitation remaining after pre-scission neutron emission is mainly transferred into intrinsic heat and less into pre-scission kinetic energy. (orig.).

  13. Interannual variations of the dominant modes of East Asian winter monsoon and possible links to Arctic sea ice

    Science.gov (United States)

    Sun, Chenghu; Yang, Song; Li, Weijing; Zhang, Ruonan; Wu, Renguang

    2016-07-01

    Two dominant modes of the winter temperature over East Asia, a northern mode and a southern mode, and their links with Arctic climate conditions are analyzed. The relationships of the two modes with Arctic sea ice are different. The northern mode is closely linked to variations in sea ice of the Arctic Barents-Laptev Sea in previous autumn and most of the Arctic in concurrent winter. The southern mode seems independent from the Arctic sea ice variations, but is associated with sea surface temperature (SST) anomalies in the equatorial central-eastern Pacific. Results suggest an effect of Arctic sea ice variation on the northern mode and an influence of tropical SST anomalies on the southern mode. Reduced sea ice over the Arctic increases 1000-500-hPa thickness over the high-latitudes of Eurasian continent, which reduces the meridional thickness gradient between the middle and high latitudes and thus weakens the extratropical upper-level zonal wind. The weakened zonal wind provides a favorable dynamic condition for the development of a high-latitude ridge around the Ural Mountain. Reduced Arctic sea ice also tends to enhance the Siberian high through both thermodynamic and dynamic processes. The above atmospheric circulation patterns provide a favorable condition for the intrusion of cold air to northern East Asia.

  14. On the dominant intra-seasonal modes over the East Asia-western North Pacific summer monsoon region

    Science.gov (United States)

    Ha, Kyung-Ja; Oh, Hyoeun

    2017-04-01

    Intra-seasonal monsoon prediction is the most imperative task due to high impact on 2/3 of world populations' daily life, but there remains an enduring challenge in climate science. The present study aims to provide a physical understanding of the sources for prediction of dominant intra-seasonal modes in the East Asian-western North Pacific summer monsoon (EA-WNPSM): preMeiyu&Baiu, Changma&Meiyu, WNPSM, and monsoon gyre modes classified by the self-organizing map analysis. The major modes tend to be dominated by the moisture convergence of the moisture budget equation along the rain-band. The preMeiyu-Baiu mode is strongly linked to both the anomalous low-level convergence and vertical wind shear through baroclinic instability, and the Changma&Meiyu mode has a strengthened tropic-subtropics connection along the western north Pacific subtropical high, which induces vertical destabilization and strong convective instability. The WNPSM and monsoon gyre modes are characterized by anomalous southeasterly flow of warm and moist air from western north Pacific monsoon, and low-level easterly flow, respectively. Prominent difference in response to the ENSO leads to different effects of the Indian Ocean and western Pacific thermal state, and consequently, the distinct moisture supply and instability variations for the EASM intra-seasonal modes. We discuss the major driving forces of sub-seasonal variability over EA-WNPSM regions. Lastly we attempted to determine the predictability sources for the four modes in the EA-WNPSM. The selected predictors are based on the persistent and tendency signals of the SST/2m air temperature and sea level pressure fields, which reflect the asymmetric response to the ENSO and the ocean and land surface anomalous conditions. For the preMeiyu&Baiu mode, the SST cooling tendency over the WNP, which persists into summer, is the distinguishing contributor that results in strong baroclinic instability. A major precursor for the Changma&Meiyu mode

  15. Directed transport of bacteria-based drug delivery vehicles: bacterial chemotaxis dominates particle shape.

    Science.gov (United States)

    Sahari, Ali; Traore, Mahama A; Scharf, Birgit E; Behkam, Bahareh

    2014-10-01

    Several attenuated and non-pathogenic bacterial species have been demonstrated to actively target diseased sites and successfully deliver plasmid DNA, proteins and other therapeutic agents into mammalian cells. These disease-targeting bacteria can be employed for targeted delivery of therapeutic and imaging cargos in the form of a bio-hybrid system. The bio-hybrid drug delivery system constructed here is comprised of motile Escherichia coli MG1655 bacteria and elliptical disk-shaped polymeric microparticles. The transport direction for these vehicles can be controlled through biased random walk of the attached bacteria in presence of chemoattractant gradients in a process known as chemotaxis. In this work, we utilize a diffusion-based microfluidic platform to establish steady linear concentration gradients of a chemoattractant and investigate the roles of chemotaxis and geometry in transport of bio-hybrid drug delivery vehicles. Our experimental results demonstrate for the first time that bacterial chemotactic response dominates the effect of body shape in extravascular transport; thus, the non-spherical system could be more favorable for drug delivery applications owing to the known benefits of using non-spherical particles for vascular transport (e.g. relatively long circulation time).

  16. Conversion of the dominantly ideal perturbations into a tearing mode after a sawtooth crash

    NARCIS (Netherlands)

    Igochine, V.; Gude, A.; S. Günter,; Lackner, K.; Yu, Q.; Orte, L. B.; Bogomolov, A.; Classen, I.; McDermott, R. M.; N C Luhmann Jr.,; ASDEX Upgrade team,

    2014-01-01

    Forced magnetic reconnection is a topic of common interest in astrophysics, space science, and magnetic fusion research. The tearing mode formation process after sawtooth crashes implies the existence of this type of magnetic reconnection and is investigated in great detail in the ASDEX Upgrade toka

  17. New Receiving Mode of Extinction for Determining Particle Size and Density without Convex Lens

    Institute of Scientific and Technical Information of China (English)

    WU Weiliang; CHEN Hanping; CAI Xiaoshu; WANG Naining

    2002-01-01

    In this article a new receiving mode for scattering light by particle is theoretically discussed. Using this receiving mode the convex lens can be omitted during determining the extinction of particle. Therefore the extinction coefficient of sphere particles is redefined by extrapolating the conventional one. In terms of the calculation results of light scattering the definition of near-field extinction coefficient of a swarm particle is depicted. Through the error analysis it is proved that the error coming from the new definition of extinction coefficient is acceptable for engineering application. In addition, a technique for determining the particle size and density is presented in this article and the advantage using this receiving mode is described.

  18. Microstructure of atmospheric particles revealed by TXM and a new mode of influenza virus transmission

    Energy Technology Data Exchange (ETDEWEB)

    Bao, L.M., E-mail: baoliangman@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhang, G.L., E-mail: zhangguilin@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Lei, Q.T.; Li, Y.; Li, X.L. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Hwu, Y.K. [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Yi, J.M. [Advanced Photon Source, Argonne National Laboratory, Argonne 60439 (United States)

    2015-09-15

    For control of influenza, firstly it is important to find the real virus transmission media. Atmospheric aerosol particles are presumably one of the media. In this study, three typical atmospheric inhaled particles in Shanghai were studied by the synchrotron based transmission X-ray microscopes (TXM). Three dimensional microstructure of the particles reveals that there are many pores contained in, particularly the coal combustion fly particles which may be possible virus carrier. The particles can transport over long distance and cause long-range infections due to its light weight. We suggest a mode which is droplet combining with aerosol mode. By this mode the transmission of global and pandemic influenzas and infection between inland avian far from population and poultry or human living in cities along coast may be explained.

  19. Microstructure of atmospheric particles revealed by TXM and a new mode of influenza virus transmission

    Science.gov (United States)

    Bao, L. M.; Zhang, G. L.; Lei, Q. T.; Li, Y.; Li, X. L.; Hwu, Y. K.; Yi, J. M.

    2015-09-01

    For control of influenza, firstly it is important to find the real virus transmission media. Atmospheric aerosol particles are presumably one of the media. In this study, three typical atmospheric inhaled particles in Shanghai were studied by the synchrotron based transmission X-ray microscopes (TXM). Three dimensional microstructure of the particles reveals that there are many pores contained in, particularly the coal combustion fly particles which may be possible virus carrier. The particles can transport over long distance and cause long-range infections due to its light weight. We suggest a mode which is droplet combining with aerosol mode. By this mode the transmission of global and pandemic influenzas and infection between inland avian far from population and poultry or human living in cities along coast may be explained.

  20. Effective identification of the three particle modes generated during pulverized coal combustion

    Institute of Scientific and Technical Information of China (English)

    YU DunXi; XU MingHou; YAO Hong; LIU XiaoWei; ZHOU Ke

    2008-01-01

    Based on the mass fraction size distribution of aluminum (AI), an improved method for effectively identifying the modes of particulate matter from pulverized coal combustion is proposed in this study. It is found that the particle size distributions of coal-derived particulate matter actually have three modes, rather than just mere two. The ultrafine mode is mainly generated through the vaporization and condensation processes. The coarse mode is primarily formed by the coalescence of molten minerals, while the newly-found central mode is attributed to the heterogeneous condensation or adsorption of vaporized species on fine residual ash particles. The detailed investigation of the mass fraction size distribution of sulfur (S) further demonstrates the rationality and effectiveness of the mass fraction size distribution of the AI in identifying three particle modes. The results show that not only can the number of particle modes be identified in the mass fraction size distributions of the AI but also can their size boundaries be more accurately defined. This method provides new insights in elucidating particle formation mechanisms and their physico-chemical characteristics.

  1. Should T2K run in dominant neutrino mode to detect CP violation ?

    CERN Document Server

    Ghosh, Monojit

    2016-01-01

    The main aim of the T2K experiment in Japan is to discover CP violation in the leptonic sector by measuring the Dirac phase $\\delta_{CP}$. For that purpose T2K has already started collecting data in both neutrino and antineutrino mode. But in this work we will show that, in T2K the main role of the antineutrinos is to resolve the octant degeneracy. If the octant is known then the pure neutrino run of T2K is capable to give the maximum CP sensitivity. On the other hand in the experiment like NO$\

  2. A method for detecting the presence of organic fraction in nucleation mode sized particles

    Directory of Open Access Journals (Sweden)

    P. Vaattovaara

    2005-01-01

    Full Text Available New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm and the lower end of Aitken mode particles (d≤50 nm is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer method to shed light on the presence of an organic fraction in the nucleation mode size class in different atmospheric environments. The basic principle of the organic fraction detection is based on our laboratory UFO-TDMA measurements with organic and inorganic compounds. Our laboratory measurements indicate that the usefulness of the UFO-TDMA in the field experiments would arise especially from the fact that atmospherically the most relevant inorganic compounds do not grow in subsaturated ethanol vapor, when particle size is 10 nm in diameter and saturation ratio is about 86% or below it. Furthermore, internally mixed particles composed of ammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various oxidized organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.

  3. A method for detecting the presence of organic fraction in nucleation mode sized particles

    Directory of Open Access Journals (Sweden)

    P. Vaattovaara

    2005-06-01

    Full Text Available New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm and the lower end of Aitken mode particles (d≤50 nm is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer method to shed light on the presence of organic fraction in the nucleation mode size class in different atmospheric environments. The basic principle of the organic fraction detection is based on our laboratory UFO-TDMA measurements with organic and inorganic compounds. Our laboratory measurements indicate that the usefulness of the UFO-TDMA in the field experiments would arise especially from the fact that atmospherically the most relevant inorganic compounds do not grow in subsaturated ethanol vapor, when particle size is 10nm in diameter and saturation ratio is about 86% or below it. Furthermore, internally mixed particles composed of ammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.

  4. Impact of Energetic-Particle-Driven Geodesic Acoustic Modes on Turbulence

    Science.gov (United States)

    Zarzoso, D.; Sarazin, Y.; Garbet, X.; Dumont, R.; Strugarek, A.; Abiteboul, J.; Cartier-Michaud, T.; Dif-Pradalier, G.; Ghendrih, Ph.; Grandgirard, V.; Latu, G.; Passeron, C.; Thomine, O.

    2013-03-01

    The impact on turbulent transport of geodesic acoustic modes excited by energetic particles is evidenced for the first time in flux-driven 5D gyrokinetic simulations using the Gysela code. Energetic geodesic acoustic modes (EGAMs) are excited in a regime with a transport barrier in the outer radial region. The interaction between EGAMs and turbulence is such that turbulent transport can be enhanced in the presence of EGAMs, with the subsequent destruction of the transport barrier. This scenario could be particularly critical in those plasmas, such as burning plasmas, exhibiting a rich population of suprathermal particles capable of exciting energetic modes.

  5. Pairwise mode entanglement in Schwinger production of particle-antiparticle pairs in an electric field

    Science.gov (United States)

    Li, Yujie; Dai, Yue; Shi, Yu

    2017-02-01

    Quantum entanglement is the characteristic quantum correlation. Here, we use this concept to analyze the quantum entanglement generated by Schwinger production of particle-antiparticle pairs in an electric field, as well as the change of entanglement as a consequence of the electric field effect on a pre-existing entangled pair of particles. The system is partitioned by using momentum modes. Various kinds of pairwise mode entanglement are calculated as functions of the electric field. Both constant and pulsed electric fields are considered. The use of entanglement exposes information beyond that in particle number distributions.

  6. Acoustofluidic particle trapping, manipulation, and release using dynamic-mode cantilever sensors.

    Science.gov (United States)

    Johnson, Blake N; Mutharasan, Raj

    2016-12-19

    We show here that dynamic-mode cantilever sensors enable acoustofluidic fluid mixing and trapping of suspended particles as well as the rapid manipulation and release of trapped micro-particles via mode switching in liquid. Resonant modes of piezoelectric cantilever sensors over the 0 to 8 MHz frequency range are investigated. Sensor impedance response, flow visualization studies using dye and micro-particle tracers (100 μm diameter), and finite element simulations of cantilever modal mechanics and acoustic streaming show fluid mixing and particle trapping configurations depend on the resonant mode shape. We found trapped particles could be: (1) rapidly manipulated on millimeter length scales, and (2) released from the cantilever surface after trapping by switching between low- and high-order resonant modes (less than 250 kHz and greater than 1 MHz, respectively). Such results suggest a potentially promising future for dynamic-mode cantilevers in separations, pumping and mixing applications as well as acoustofluidic-enhanced sensing applications.

  7. Kinetic freeze-out, particle spectra, and harmonic-flow coefficients from mode-by-mode hydrodynamics

    Science.gov (United States)

    Floerchinger, Stefan; Wiedemann, Urs Achim

    2014-03-01

    The kinetic freeze-out for the hydrodynamical description of relativistic heavy-ion collisions is discussed using a background-fluctuation splitting of the hydrodynamical fields. For a single event, the particle spectrum, or its logarithm, can be written as the sum of the background part that is symmetric with respect to azimuthal rotations and longitudinal boosts and a part containing the contribution of fluctuations or deviations from the background. Using a complete orthonormal basis to characterize the initial state allows one to write the double differential harmonic-flow coefficients determined by the two-particle correlation method as matrix expressions involving the initial fluid correlations. We discuss the use of these expressions for a mode-by-mode analysis of fluctuating initial conditions in heavy-ion collisions.

  8. A method for detecting the presence of organic fraction in nucleation mode sized particles

    Science.gov (United States)

    Vaattovaara, P.; Räsänen, M.; Kühn, T.; Joutsensaari, J.; Laaksonen, A.

    2005-12-01

    New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, dammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various oxidized organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.

  9. Elucidating dominant pathways of the nano-particle self-assembly process.

    Science.gov (United States)

    Zeng, Xiangze; Li, Bin; Qiao, Qin; Zhu, Lizhe; Lu, Zhong-Yuan; Huang, Xuhui

    2016-09-14

    Self-assembly processes play a key role in the fabrication of functional nano-structures with widespread application in drug delivery and micro-reactors. In addition to the thermodynamics, the kinetics of the self-assembled nano-structures also play an important role in determining the formed structures. However, as the self-assembly process is often highly heterogeneous, systematic elucidation of the dominant kinetic pathways of self-assembly is challenging. Here, based on mass flow, we developed a new method for the construction of kinetic network models and applied it to identify the dominant kinetic pathways for the self-assembly of star-like block copolymers. We found that the dominant pathways are controlled by two competing kinetic parameters: the encounter time Te, characterizing the frequency of collision and the transition time Tt for the aggregate morphology change from rod to sphere. Interestingly, two distinct self-assembly mechanisms, diffusion of an individual copolymer into the aggregate core and membrane closure, both appear at different stages (with different values of Tt) of a single self-assembly process. In particular, the diffusion mechanism dominates the middle-sized semi-vesicle formation stage (with large Tt), while the membrane closure mechanism dominates the large-sized vesicle formation stage (with small Tt). Through the rational design of the hydrophibicity of the copolymer, we successfully tuned the transition time Tt and altered the dominant self-assembly pathways.

  10. Simulations of Damping of Trapped Particle Asymmetry Modes in Non-Neutral Plasma Columns

    Science.gov (United States)

    Mason, Grant W.; Spencer, Ross L.

    2002-11-01

    Kabantsev et al.(A. A. Kabantsev, C. F. Driscoll, T. J. Hilsabeck, T. M. O'Neil and J. H.Yu, in Non-Neutral Plasma Physics IV), AIP Conference Proceedings 606, 2001, pp. 277-286 have reported experimental observations and theory for trapped particle asymmetry modes on cylindrical electron columns. In particular, the m=1; k_z=odd mode exhibits strong damping from an unknown mechanism that is conjectured by Kabantsev et al. to be either diffusive mixing of trapped and untrapped populations of particles or spatial Landau damping. We have observed similar damping within a 3-dimensional particle-in-cell simulation. The simulation model does not include diffusive mixing. Spatial Landau damping is also ruled out because the mode frequencies in the simulation intersect the rotation frequency curve outside the plasma. We describe efforts to isolate the mechanism of the damping.

  11. Suppression of scattering for small dielectric particles: an anapole mode and invisibility

    CERN Document Server

    Luk`yanchuk, Boris; Kuznetsov, Arseniy I; Miroshnichenko, Andrey E; Kivshar, Yuri S

    2016-01-01

    We reveal that an isotropic homogeneous subwavelength particle with a high refractive index can produce ultra-weak total scattering due to vanishing contribution of the electric dipole moment. This effect can be explained with the help of the Fano resonance and scattering efficiency associated with the excitation of an anapole mode. The latter is a nonradiative mode emerging from destructive interference of electric and toroidal dipole moments, and it can be employed for a design of highly transparent optical materials.

  12. Suppression of scattering for small dielectric particles: anapole mode and invisibility.

    Science.gov (United States)

    Luk'yanchuk, Boris; Paniagua-Domínguez, Ramón; Kuznetsov, Arseniy I; Miroshnichenko, Andrey E; Kivshar, Yuri S

    2017-03-28

    We reveal that an isotropic, homogeneous, subwavelength particle with high refractive index can produce ultra-small total scattering. This effect, which follows from the inhibition of the electric dipole radiation, can be identified as a Fano resonance in the scattering efficiency and is associated with the excitation of an anapole mode in the particle. This anapole mode is non-radiative and emerges from the destructive interference of electric and toroidal dipoles. The invisibility effect could be useful for the design of highly transparent optical materials.This article is part of the themed issue 'New horizons for nanophotonics'. © 2017 The Author(s).

  13. Superdiffusion dominates intracellular particle motion in the supercrowded space of pathogenic Acanthamoeba castellanii

    CERN Document Server

    Reverey, J F; Bao, H; Leippe, M; Metzler, R; Selhuber-Unkel, C

    2015-01-01

    Acanthamoebae are free-living protists and human pathogens, whose cellular functions and pathogenicity strongly depend on the transport of intracellular vesicles and granules through the cytosol. Using high-speed live cell imaging in combination with single-particle tracking analysis, we show here that the motion of endogenous intracellular particles in the size range from a few hundred nanometers to several micrometers in Acanthamoeba castellanii is strongly superdiffusive and influenced by cell locomotion, cytoskeletal elements, and myosin II. We demonstrate that cell locomotion significantly contributes to intracellular particle motion, but is clearly not the only origin of superdiffusivity. By analyzing the contribution of microtubules, actin, and myosin II motors we show that myosin II is a major driving force of intracellular motion in A. castellanii. The cytoplasm of A. castellanii is supercrowded with intracellular vesicles and granules, such that significant intracellular motion can only be achieved ...

  14. Superdiffusion dominates intracellular particle motion in the supercrowded cytoplasm of pathogenic Acanthamoeba castellanii

    Science.gov (United States)

    Reverey, Julia F.; Jeon, Jae-Hyung; Bao, Han; Leippe, Matthias; Metzler, Ralf; Selhuber-Unkel, Christine

    2015-06-01

    Acanthamoebae are free-living protists and human pathogens, whose cellular functions and pathogenicity strongly depend on the transport of intracellular vesicles and granules through the cytosol. Using high-speed live cell imaging in combination with single-particle tracking analysis, we show here that the motion of endogenous intracellular particles in the size range from a few hundred nanometers to several micrometers in Acanthamoeba castellanii is strongly superdiffusive and influenced by cell locomotion, cytoskeletal elements, and myosin II. We demonstrate that cell locomotion significantly contributes to intracellular particle motion, but is clearly not the only origin of superdiffusivity. By analyzing the contribution of microtubules, actin, and myosin II motors we show that myosin II is a major driving force of intracellular motion in A. castellanii. The cytoplasm of A. castellanii is supercrowded with intracellular vesicles and granules, such that significant intracellular motion can only be achieved by actively driven motion, while purely thermally driven diffusion is negligible.

  15. Field measurements of hygroscopic properties and state of mixing of nucleation mode particles

    Directory of Open Access Journals (Sweden)

    M. Väkevä

    2001-12-01

    Full Text Available An Ultrafine Tandem Differential Mobility Analyser (UF-TDMA has been used in several field campaigns over the last few years. The investigations were focused on the origin and properties of nucleation event aerosols, which are observed frequently in various environments. This paper gives a summary of the results of 10 nm and 20 nm particle hygroscopic properties from different measurement sites: an urban site, an urban background site and a forest site in Finland and a coastal site in western Ireland. The data can be classified in four hygroscopic growth classes: hydrofobic, less-hygroscopic, more-hygroscopic and sea-salt. Similar classification has been earlier presented for Aitken and accumulation mode particles. In urban air, the summertime 10 nm particles showed varying less-hygroscopic growth behaviour, while winter time 10 nm and 20 nm particles were externally mixed with two different hygroscopic growth modes. The forest measurements revealed diurnal behaviour of hygroscopic growth, with high growth factors at day time and lower during night. The urban background particles had growth behaviour similar to the urban and forest measurement sites depending on the origin of the observed particles. The coastal measurements were strongly affected by air mass history. Both 10 nm and 20 nm particles were hygroscopic in marine background air. The 10 nm particles produced during clean nucleation burst periods were hydrofobic. Diurnal variation and higher growth factors of 10 nm particles were observed in air affected by other source regions. External mixing was occasionally observed at all the sites, but incidents with more than two growth modes were extremely rare.

  16. Analysis of Particle-Stimulated Nucleation (PSN)-Dominated Recrystallization for Hot-Rolled 7050 Aluminum Alloy

    Science.gov (United States)

    Adam, Khaled F.; Long, Zhengdong; Field, David P.

    2017-04-01

    In 7xxx series aluminum alloys, the constituent large and small second-phase particles present during deformation process. The fraction and spatial distribution of these second-phase particles significantly influence the recrystallized structure, kinetics, and texture in the subsequent treatment. In the present work, the Monte Carlo Potts model was used to model particle-stimulated nucleation (PSN)-dominated recrystallization and grain growth in high-strength aluminum alloy 7050. The driving force for recrystallization is deformation-induced stored energy, which is also strongly affected by the coarse particle distribution. The actual microstructure and particle distribution of hot-rolled plate were used as an initial point for modeling of recrystallization during the subsequent solution heat treatment. Measurements from bright-field TEM images were performed to enhance qualitative interpretations of the developed microstructure. The influence of texture inhomogeneity has been demonstrated from a theoretical point of view using pole figures. Additionally, in situ annealing measurements in SEM were performed to track the orientational and microstructural changes and to provide experimental support for the recrystallization mechanism of PSN in AA7050.

  17. Particle and power deposition on divertor targets in EAST H-mode plasmas

    DEFF Research Database (Denmark)

    Wang, L.; Xu, G.S.; Guo, H.Y.

    2012-01-01

    The effects of edge-localized modes (ELMs) on divertor particle and heat fluxes were investigated for the first time in the Experimental Advanced Superconducting Tokamak (EAST). The experiments were carried out with both double null and lower single null divertor configurations, and comparisons w...

  18. Chemical composition of nucleation and accumulation mode particles collected in Vienna, Austria

    Science.gov (United States)

    Puxbaum, Hans; Wopenka, Brigitte

    Atmospheric aerosol samples were collected by six-stage low pressure impactors in Vienna downtown. Aerosol particles were deposited on aluminum foils in five size fractions in the size range of 0.04-25 μm AD. The concentration of the components Cl -, Br -, NO 3-, SO 42-, Ca, Cu, Fe, Mg, Pb. Sr, Zn and total C was determined by multi-element analytical methods. A comparison of the relative composition of the size fractions containing nucleation mode and accumulation mode particles showed the components derived from traffic emissions (Pb, Br - and C) to be significantly enriched in the nucleation mode size fraction. On the other hand, each of the components Cl -, SO 42-,Ca, Cu, Fe, Mg and Sr has a similar relative concentration in the nucleation mode and in the accumulation mode size fraction. For all samples collected on days with prevailing westerly winds a strong negative correlation between wind speed and sulfate particle size as well as sulfate concentration was observed.

  19. Small-scale microwave-background anisotropies in a universe dominated by nonrelativistic particles

    Energy Technology Data Exchange (ETDEWEB)

    Doroshkevich, A.G.

    1985-10-01

    Instantaneous hydrogen recombination is the premise of the present predictions of the small scale anisotropies in background cosmic radiation temperature, for the case of an early universe model that is dominated by heavy neutrinos. On the basis of the relationship established between the temperature fluctuation parameters and the correlation radius r(0) of the galaxy distribution, an r(0) value of 4.5/(100 km/sec Mpc)/H(0)/Mpc implies a fluctuation amplitude below 0.00001; the minimum fluctuation amplitude value will depend on the amplitude of the primordial density fluctuations, the current horizon distance, and the Jeans scale at the recombination epoch. 18 references.

  20. Model for Quasinormal Mode Excitation by a Particle Plunging into a Black Hole

    Science.gov (United States)

    Mark, Zachary; Zimmerman, Aaron; Yang, Huan; Chen, Yanbei

    2016-03-01

    It is known that the late time gravitational waveform produced by a particle plunging into a Kerr black hole is well described by a sum of quasinormal modes. However it is not yet understood how the early part of the waveform gives way to the quasinormal mode description, which diverges at early times, nor how the inhomogenous part of the waveform contributes. Motivated by, we offer a model for quasinormal mode excitation by a particle plunging into a Schwarzschild black hole. To develop our model we study approximations to the Regge-Wheeler equation that allow for a closed-form expression for the frequency-domain Green's function, which we use to isolate the component of the waveform that should be identified with quasinormal ringing. Our description of quasinormal ringing does not diverge at early times and reveals that quasinormal ringing should be understood in analogy with a damped harmonic oscillator experiencing a transient driving source.

  1. Laboratory studies of immersion and deposition mode ice nucleation of ozone aged mineral dust particles

    Directory of Open Access Journals (Sweden)

    Z. A. Kanji

    2013-04-01

    Full Text Available Ice nucleation in the atmosphere is central to the understanding the microphysical properties of mixed-phase and cirrus clouds. Ambient conditions such as temperature (T and relative humidity (RH, as well as aerosol properties such as chemical composition and mixing state play an important role in predicting ice formation in the troposphere. Previous field studies have reported the absence of sulphate and organic compounds on mineral dust ice crystal residuals sampled at mountain top stations or aircraft based measurements despite the long range transport mineral dust is subjected to. We present laboratory studies of ice nucleation for immersion and deposition mode on ozone aged mineral dust particles for 233 T ns are reported and observed to increase as a function of temperature. We present first results that demonstrate enhancement of the ice nucleation ability of aged mineral dust particles in both the deposition and immersion mode due to ageing. Additionally, these are also the first results to show a suppression of heterogeneous ice nucleation without the condensation of a coating of (inorganic material. In immersion mode, low exposure Ka particles showed enhanced ice activity requiring a median freezing temperature of 1.5 K warmer than that of untreated Ka whereas high exposure ATD particles showed suppressed ice nucleation requiring a median freezing temperature of 3 K colder than that of untreated ATD. In deposition mode, low exposure Ka had ice active fractions of an order of magnitude higher than untreated Ka, where as high exposure ATD had ice active fractions up to a factor of 4 lower than untreated ATD. Based on our results, we present parameterizations in terms of ns(T that can represent ice nucleation of atmospherically aged and non-aged particles for both immersion and deposition mode. We find excellent agreement (to within less than a factor of 2 with field measurements when parameterizations derived from our results are used to

  2. Correlations between the fragmentation modes and light charged particles emission in heavy ion collisions

    CERN Document Server

    Zhang, Yingxun; Chen, Jixian; Wang, Ning; Zhao, Kai; Li, Zhuxia

    2015-01-01

    The correlations between the shape of rapidity distribution of the yield of light charged particles and the fragmentation modes in semi-peripheral collisions for $^{70}$Zn+$^{70}$Zn, $^{64}$Zn+$^{64}$Zn and $^{64}$Ni+$^{64}$Ni at the beam energy of 35MeV/nucleon are investigated based on ImQMD05 code. Our studies show there is an interplay between the binary, ternary and multi-fragmentation break-up modes. The binary and ternary break-up modes more prefer to emit light charged particles at middle rapidity and give larger values of $R_{yield}^{mid}$ compared with the multi-fragmentation break-up mode does. The reduced rapidity distribution for the normalized yields of p, d, t, $^3$He, $^4$He and $^6$He and the corresponding values of $R_{yield}^{mid}$ can be used to estimate the probability of multi-fragmentation break-up modes. By comparing to experimental data, our results illustrate that $\\ge$40\\% of the collisions events belong to the multi-fragmentation break-up mode for the reactions we studied.

  3. Correlation between the fragmentation modes and light charged particles emission in heavy ion collisions

    Institute of Scientific and Technical Information of China (English)

    ZHANG YingXun[1; ZHOU ChengShuang[1,2; CHEN JiXian[1,2; WANG Ning[2; ZHAO Kai[1; LI ZhuXia[1

    2015-01-01

    The correlation between the shape of rapidity distribution of the yield of light charged particles and the fragmentation modes in semi-peripheral collisions for 70Zn+70Zn, 64Zn+64Zn and 64Ni+64Ni at the beam energy of 35 MeV/nucleon is investigated based on ImQMD05 code. Our studies show there is an interplay between the binary, ternary and multi-fragmentation break-up modes. The binary and ternary break-up modes more prefer to emit light charged particles at middle rapidity and give larger values of Rmid compared with the multi-fragmentation break-up mode does. The reduced rapidity distribution for the normalized yields of yield p, d, t, 3He, 4He and 6He and the corresponding values ~ Rmid oI yield can be used to estimate the probability of multi-fragmentation break-up modes. By comparing to experimental data, our results illustrate that ~40% of the collisions events belong to the multi- fragmentation break-up mode for the reactions we studied.

  4. Export and losses of blue carbon-derived particulate and dissolved organic carbon (POC and DOC) in blackwater river-dominated and particle-dominated estuaries

    Science.gov (United States)

    Arellano, A. R.; Bianchi, T. S.; Osburn, C. L.; D'Sa, E. J.; Oviedo Vargas, D.; Ward, N. D.; Joshi, I.; Ko, D. S.

    2016-12-01

    Globally, coastal blue carbon environments (wetlands, seagrass beds and mangroves) sequester an estimated 67-215 Tg C yr-1. While most blue carbon research has focused on carbon burial/stocks and habitat fragmentation of these communities, few studies have examined the export and loss of blue carbon sources of particulate organic matter (POM) and dissolved organic matter (DOM) to adjacent coastal waters. These shifts in losses of DOM and POM are also partly due to large-scale changes in land-use and climate change. Due to the complexity of vascular plant inputs to estuarine systems (e.g. terrestrial vs. blue carbon), being able to separate blue carbon sources of POM and DOM are critical. Here, we investigate the temporal variability of the abundance, sources and breakdown of particulate and dissolved organic carbon (POC and DOC) in particle-dominated (Barataria Bay) and blackwater river-dominated (Apalachicola Bay) estuaries in the northern Gulf of Mexico, using bulk carbon, dissolved lignin phenols, δ13C and dissolved CO2. The range of DOC:POC ratios for Barataria and Apalachicola bays were 0.5-3.1 and 2.3-57.0, respectively. δ13C-POC values were more depleted in Apalachicola (x̅=-27.3‰) compared to those in Barataria (x̅=-24.8‰), and C:N ratios were higher in Apalachicola (x̅=10.8) than in Barataria (x̅=9.3). Although there was no significant temporal variability with δ13C-POC in both systems, Barataria Bay had the highest POC (0.08-0.23 mM) and C:N (7.0-13.4) values during spring, when enhanced southerly winds likely resulted in higher resuspension and marsh erosion rates. Additionally, in Apalachicola, the lowest C:N values (6.2-16.1) were observed during the dry season when fluvial DOM inputs were minimal. The highest dissolved lignin phenol and DOC (0.10-2.98 mM) concentrations in Apalachicola occurred during the wet season, reflecting the importance of riverine inputs to this system. In particular, the Carabelle River plume region had C:V and S

  5. Damping of high-lying single-particle modes in heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gales, S.; Stoyanov, C.; Vdovin, A.I.

    1988-08-01

    The recent experimental and theoretical results on the damping of high-lying single-particle modes in heavy nuclei are reviewed. In one-nucleon transfer reactions these states manifest themselves as broad 'resonance'-like structures superimposed on a large continuum. The advantages and the limitations of the transfer reaction approach will be presented using the results from neutron and proton pick-up and stripping reactions. The problem raised by the subtraction of the underlying background, the assumptions made to describe the reaction process and the method used to extract the strength distributions are presented. The existing empirical systematics is summarized for nuclei ranging from /sup 90/Zr to /sup 208/Pb. The theoretical approaches used to explain the damping of the high-lying single-particle modes are based on the coupling between collective and single-particle degrees of freedom. In a first step the bare single-particle mode is spread over several doorway collective states due to the interaction with surface vibrations. In a second step the doorway states spread their strengths over many other degrees of freedom. These two steps of the damping mechanism are discussed in detail within the framework of the quasiparticle-phonon nuclear model. A large-scale comparison between the measured and calculated average energies, spreading widths and spectroscopic strengths of the high-lying single-particle (hole) states in heavy nuclei is presented. The systematic features of the damping (energy, angular momentum and isotopic dependence) are discussed. Recent advances of the experimental approaches, such as the ..gamma..-decay of the high-lying states or the use of heavy-ion transfer reactions at intermediate energies, are outlined. The detailed study of the damping mechanism of high-lying single-particle modes reveals new features and leads us to a new field in nuclear structure: 'The spectroscopy of inner and outer subshells'.

  6. Efficiency of the deposition mode ice nucleation on mineral dust particles

    Directory of Open Access Journals (Sweden)

    O. Möhler

    2006-01-01

    Full Text Available The deposition mode ice nucleation efficiency of various dust aerosols was investigated at cirrus cloud temperatures between 196 and 223 K using the aerosol and cloud chamber facility AIDA (Aerosol Interaction and Dynamics in the Atmosphere. Arizona test dust (ATD as a reference material and two dust samples from the Takla Makan desert in Asia (AD1 and the Sahara (SD2 were used for the experiments at simulated cloud conditions. The dust particle sizes were almost lognormally distributed with mode diameters between 0.3 and 0.5 μm and geometric standard deviations between 1.6 and 1.9. Deposition ice nucleation was most efficient on ATD particles with ice-active particle fractions of about 0.6 and 0.8 at an ice saturation ratio SiSiSi. This indicates that deposition ice nucleation on mineral particles may not be treated in the same stochastic sense as homogeneous freezing. The suggested formulation of ice activation spectra may be used to calculate the formation rate of ice crystals in models, if the number concentration of dust particles is known. More experimental work is needed to quantify the variability of the ice activation spectra as function of the temperature and dust particle properties.

  7. Suppression of nucleation mode particles by biomass burning in an urban environment: a case study.

    Science.gov (United States)

    Agus, Emily L; Lingard, Justin J N; Tomlin, Alison S

    2008-08-01

    Measurements of concentrations and size distributions of particles 4.7 to 160 nm were taken using an SMPS during the bonfire and firework celebrations on Bonfire Night in Leeds, UK, 2006. These celebrations provided an opportunity to study size distributions in a unique atmospheric pollution situation during and following a significant emission event due to open biomass burning. A log-normal fitting program was used to determine the characteristics of the modal groups present within hourly averaged size distributions. Results from the modal fitting showed that on bonfire night the smallest nucleation mode, which was present before and after the bonfire event and on comparison weekends, was not detected within the size distribution. In addition, there was a significant shift in the modal diameters of the remaining modes during the peak of the pollution event. Using the concept of a coagulation sink, the atmospheric lifetimes of smaller particles were significantly reduced during the pollution event, and thus were used to explain the disappearance of the smallest nucleation mode as well as changes in particle count mean diameters. The significance for particle mixing state is discussed.

  8. Design of Miniaturized Dominant Mode Leaky-Wave Antenna with Backfire-to-Endfire Scanning Capability by using Metamaterials

    Directory of Open Access Journals (Sweden)

    Dileep K. Upadhyay

    2012-08-01

    Full Text Available A new miniaturized dominant mode leaky-wave antenna is proposed. This antenna is a transmission line structure with radiating wavenumber increasing from negative to positive values, providing backward to forward scanning capability as frequency is increased. The antenna profile is designed based on microstrip technology using balanced composite right left handed transmission lines (CRLH TL approach. The balanced CRLH TL is designed based on cascaded combination of inter digital capacitor (IDC in series and vias to the ground plane at the bended stub ends in shunt. Bended stubs are used in each section for the purpose of miniaturization. Dispersion characteristics of CRLH TL shows the left handed region, right handed region and balanced design of composite right left handed metamaterial. The radiation pattern of the proposed antenna confirms the full scanability i.e. backfire-to-endfire scanning capability of the antenna. The characteristics and performances of the antenna are demonstrated by full-wave electromagnetic simulator based on method of moments and all characteristics and performances are verified by another full-wave electromagnetic simulator based on integrated equations.

  9. Particle-in-cell simulations of particle energization from low Mach number fast mode shocks

    CERN Document Server

    Park, Jaehong; Blackman, Eric G; Ren, Chuang; Siller, Robert

    2012-01-01

    Astrophysical shocks are often studied in the high Mach number limit but weakly compressive fast shocks can occur in magnetic reconnection outflows and are considered to be a site of particle energization in solar flares. Here we study the microphysics of such perpendicular, low Mach number collisionless shocks using two-dimensional particle-in-cell (PIC) simulations with a reduced ion/electron mass ratio and employ a moving wall boundary method for initial generation of the shock. This moving wall method allows for more control of the shock speed, smaller simulation box sizes, and longer simulation times than the commonly used fixed wall, reflection method of shock formation. Our results, which are independent of the shock formation method, reveal the prevalence shock drift acceleration (SDA) of both electron and ions in a purely perpendicular shock with Alfv\\'en Mach number $M_A=6.8$ and ratio of thermal to magnetic pressure $\\beta=8$. We determine the respective minimum energies required for electrons and ...

  10. Experimental investigation of the radial structure of energetic particle driven modes

    CERN Document Server

    Horvath, L; Lauber, Ph; Por, G; Gude, A; Igochine, V; Geiger, B; Maraschek, M; Guimarais, L; Nikolaeva, V; Pokol, G I

    2016-01-01

    Alfv\\'en eigenmodes (AEs) and energetic particle modes (EPMs) are often excited by energetic particles (EPs) in tokamak plasmas. One of the main open questions concerning EP driven instabilities is the non-linear evolution of the mode structure. The aim of the present paper is to investigate the properties of beta-induced AEs (BAEs) and EP driven geodesic acoustic modes (EGAMs) observed in the ramp-up phase of off-axis NBI heated ASDEX Upgrade (AUG) discharges. This paper focuses on the changes in the mode structure of BAEs/EGAMs during the non-linear chirping phase. Our investigation has shown that in case of the observed down-chirping BAEs the changes in the radial structure are smaller than the uncertainty of our measurement. This behaviour is most probably the consequence of that BAEs are normal modes, thus their radial structure strongly depends on the background plasma parameters rather than on the EP distribution. In the case of rapidly upward chirping EGAMs the analysis consistently shows shrinkage of...

  11. Whimsicality of multi-mode Hasegawa space-charge waves in a complex plasma containing collision-dominated electrons and streaming ions

    Science.gov (United States)

    Lee, Myoung-Jae; Jung, Young-Dae

    2017-09-01

    The influence of collision-dominated electrons on multi-mode Hasegawa space-charge waves are investigated in a complex plasma containing streaming ions. The dispersion relation for the multi-mode Hasegawa space-charge wave propagating in a cylindrical waveguide filled with dusty plasma containing collision-dominated electrons and streaming ions is derived by using the fluid equations and Poisson’s equation which lead to a Bessel equation. By the boundary condition, the roots of the Bessel function would characterize the property of space-charge wave propagation. It is found that two solutions exist for wave frequency, which are affected by the radius of waveguide and the roots of the Bessel function. The damping and growing modes are found to be enhanced by an increase of the radius. However, an increase of electron collision frequency would suppress the damping and the growing modes of the propagating space-charge wave in a cylindrical waveguide plasma.

  12. Exposure to negatively charged-particle dominant air-conditions on human lymphocytes in vitro activates immunological responses.

    Science.gov (United States)

    Nishimura, Yasumitsu; Takahashi, Kazuaki; Mase, Akinori; Kotani, Muneo; Ami, Kazuhisa; Maeda, Megumi; Shirahama, Takashi; Lee, Suni; Matsuzaki, Hidenori; Kumagai-Takei, Naoko; Yoshitome, Kei; Otsuki, Takemi

    2015-12-01

    Indoor air-conditions may play an important role in human health. Investigation of house conditions that promote health revealed that negatively charged-particle dominant indoor air-conditions (NAC) induced immune stimulation. NAC was established using fine charcoal powder on walls and ceilings and utilizing forced negatively charged particles (approximate diameter: 20 nm) dominant in indoor air-conditions created by applying an electric voltage (72 V) between the backside of the walls and the ground. We reported previously that these conditions induced a slight and significant increase of interleukin-2 during 2.5 h stay, and an increase of natural killer (NK) cell cytotoxicity, when examining human subjects after a two-week night stay under these conditions. In the present study, we investigated whether exposure to NAC in vitro affects immune conditions. Although the concentrations of particles were different, an incubator for cell culture with NAC was set and cellular compositions and functions of various freshly isolated human lymphocytes derived from healthy donors were assayed in the NAC incubator and compared with those of cultures in a standard (STD) incubator. Results showed that NAC cultivation caused an increase of CD25 and PD-1 expressing cells in the CD4 positive fraction, enhancement of NK cell cytotoxicity, production of interferon-y (IFNγ), and slight enhancement of regulatory T cell function. In addition, the formula designated as the "immune-index" clearly differed between STD and NAC culture conditions. Thus, NAC conditions may promote human health through slight activation of the immune system against cancer cells and virus infection as shown by this in vitro study and our previously reported human studies.

  13. Optimal location and setting of SVC and TCSC devices using non-dominated sorting particle swarm optimization

    Energy Technology Data Exchange (ETDEWEB)

    Benabid, R. [Nuclear Research Center of Birine, B.P. 180, 17200 Ain oussera, Djelfa (Algeria); Boudour, M. [Department of Electrical Engineering University of Sciences and Technology Houari Boumediene (U.S.T.H.B), El Alia, BP 32, Bab Ezzouar, 16111 Algiers (Algeria); Abido, M.A. [Electrical Engineering Department, King Fahd University of Petroleum and Mineral, Box 1225, Dhahran 183 (Saudi Arabia)

    2009-12-15

    In this paper, a new method for optimal locating multi-type FACTS devices in order to optimize multi-objective voltage stability problem is presented. The proposed methodology is based on a new variant of particle swarm optimization (PSO) specialized in multi-objective optimization problem known as non-dominated sorting particle swarm optimization (NSPSO). The crowding distance technique is used to maintain the Pareto front size at the chosen limit, without destroying its characteristics. To aid the decision maker choosing the best compromise solution from the Pareto front, the fuzzy-based mechanism is employed for this task. NSPSO is used to find the optimal location and setting of two types of FACTS namely: Thyristor controlled series compensator (TCSC) and static var compensator (SVC) that maximize static voltage stability margin (SVSM), reduce real power losses (RPL), and load voltage deviation (LVD). The optimization is carried out on two and three objective functions for various FACTS combinations considering. For ensure the robustness of the proposed method and gives a practical sense of our study, N - 1 contingency analysis and the stress of power system is considered in the optimization process. The thermal limits of lines and voltage limits of load buses are considered as the security constraints. The proposed method is validated on IEEE 30-bus and realistic Algerian 114-bus power system. The simulation results are compared with those obtained by particle swarm optimization (PSO) and non-dominated sorting genetic algorithms (NSGA-II). The comparisons show the effectiveness of the proposed NSPSO to solve the multi-objective optimization problem and capture Pareto optimal solutions with satisfactory diversity characteristics. (author)

  14. Dominant particles and reactions in a two-temperature chemical kinetic model of a decaying SF6 arc

    Science.gov (United States)

    Wang, Xiaohua; Gao, Qingqing; Fu, Yuwei; Yang, Aijun; Rong, Mingzhe; Wu, Yi; Niu, Chunping; Murphy, Anthony B.

    2016-03-01

    This paper is devoted to the computation of the non-equilibrium composition of an SF6 plasma, and determination of the dominant particles and reactions, at conditions relevant to high-voltage circuit breakers after current zero (temperatures from 12 000 K to 1000 K and a pressure of 4 atm). The non-equilibrium composition is characterized by departures from both thermal and chemical equilibrium. In thermal non-equilibrium process, the electron temperature (T e) is not equal to the heavy-particle temperature (T h), while for chemical non-equilibrium, a chemical kinetic model is adopted. In order to evaluate the reasonableness and reliability of the non-equilibrium composition, calculation methods for equilibrium composition based on Gibbs free energy minimization and kinetic composition in a one-temperature kinetic model are first considered. Based on the one-temperature kinetic model, a two-temperature kinetic model with the ratio T e/T h varying as a function of the logarithm of electron density ratio (n e/n\\text{e}\\max ) was established. In this model, T* is introduced to allow a smooth transition between T h and T e and to determine the temperatures for the rate constants. The initial composition in the kinetic models is obtained from the asymptotic composition as infinite time is approached at 12 000 K. The molar fractions of neutral particles and ions in the two-temperature kinetic model are consistent with the equilibrium composition and the composition obtained from the one-temperature kinetic model above 10 000 K, while significant differences appear below 10 000 K. Based on the dependence of the particle distributions on temperature in the two-temperature kinetic model, three temperature ranges, and the dominant particles and reactions in the respective ranges, are determined. The full model is then simplified into three models and the accuracy of the simplified models is assessed. The simplified models reduce the number of species and

  15. Emission and deposition of accumulation and coarse mode particles in the Amazon basin

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2010-06-01

    Full Text Available Size-resolved vertical aerosol number fluxes of particles in the diameter range 0.25–2.5 μm were measured with the eddy covariance method from a 53 m high tower over the Amazon rain forest, 60 km NNW of Manaus, Brazil. This study focuses on data measured during the relatively clean wet season, but a shorter measurement period from the more polluted dry season is used as a comparison.

    Size-resolved net particle fluxes of the five lowest size bins, representing 0.25–0.45 μm in diameter, pointed downward in more or less all wind sectors in the wet season. This is an indication that the source of primary biogenic aerosol particles may be small in this particle size range. In the diameter range 0.5–2.5 μm, vertical particle fluxes were highly dependent on wind direction. In wind sectors where anthropogenic influence was low, net emission fluxes dominated. However, in wind sectors associated with higher anthropogenic influence, net deposition fluxes dominated. The net emission fluxes were interpreted as primary biogenic aerosol emission, but deposition of anthropogenic particles seems to have masked this emission in wind sectors with higher anthropogenic influence. The emission fluxes were at maximum in the afternoon when the mixed layer is well developed, and these emissions were best correlated with horizontal wind speed by the equation

    log10F=0.47·U+2.26

    where F is the emission number flux of 0.5–2.5 μm particles [m−2s−1] and U is the horizontal wind speed [ms−1] at the top of the tower.

  16. Laboratory studies of immersion and deposition mode ice nucleation of ozone aged mineral dust particles

    Science.gov (United States)

    Kanji, Z. A.; Welti, A.; Chou, C.; Stetzer, O.; Lohmann, U.

    2013-09-01

    Ice nucleation in the atmosphere is central to the understanding the microphysical properties of mixed-phase and cirrus clouds. Ambient conditions such as temperature (T) and relative humidity (RH), as well as aerosol properties such as chemical composition and mixing state play an important role in predicting ice formation in the troposphere. Previous field studies have reported the absence of sulfate and organic compounds on mineral dust ice crystal residuals sampled at mountain top stations or aircraft based measurements despite the long-range transport mineral dust is subjected to. We present laboratory studies of ice nucleation for immersion and deposition mode on ozone aged mineral dust particles for 233 < T < 263 K. Heterogeneous ice nucleation of untreated kaolinite (Ka) and Arizona Test Dust (ATD) particles is compared to corresponding aged particles that are subjected to ozone concentrations of 0.4-4.3 ppmv in a stainless steel aerosol tank. The portable ice nucleation counter (PINC) and immersion chamber combined with the Zurich ice nucleation chamber (IMCA-ZINC) are used to conduct deposition and immersion mode measurements, respectively. Ice active fractions as well as ice active surface site densities (ns) are reported and observed to increase as a function of decreasing temperature. We present first results that demonstrate enhancement of the ice nucleation ability of aged mineral dust particles in both the deposition and immersion mode due to ageing. We also present the first results to show a suppression of heterogeneous ice nucleation activity without the condensation of a coating of (in)organic material. In immersion mode, low ozone exposed Ka particles showed enhanced ice activity requiring a median freezing temperature of 1.5 K warmer than that of untreated Ka, whereas high ozone exposed ATD particles showed suppressed ice nucleation requiring a median freezing temperature of 3 K colder than that of untreated ATD. In deposition mode, low

  17. Laboratory studies of immersion and deposition mode ice nucleation of ozone aged mineral dust particles

    Directory of Open Access Journals (Sweden)

    Z. A. Kanji

    2013-09-01

    Full Text Available Ice nucleation in the atmosphere is central to the understanding the microphysical properties of mixed-phase and cirrus clouds. Ambient conditions such as temperature (T and relative humidity (RH, as well as aerosol properties such as chemical composition and mixing state play an important role in predicting ice formation in the troposphere. Previous field studies have reported the absence of sulfate and organic compounds on mineral dust ice crystal residuals sampled at mountain top stations or aircraft based measurements despite the long-range transport mineral dust is subjected to. We present laboratory studies of ice nucleation for immersion and deposition mode on ozone aged mineral dust particles for 233 T ns are reported and observed to increase as a function of decreasing temperature. We present first results that demonstrate enhancement of the ice nucleation ability of aged mineral dust particles in both the deposition and immersion mode due to ageing. We also present the first results to show a suppression of heterogeneous ice nucleation activity without the condensation of a coating of (inorganic material. In immersion mode, low ozone exposed Ka particles showed enhanced ice activity requiring a median freezing temperature of 1.5 K warmer than that of untreated Ka, whereas high ozone exposed ATD particles showed suppressed ice nucleation requiring a median freezing temperature of 3 K colder than that of untreated ATD. In deposition mode, low exposure Ka had ice active fractions of an order of magnitude higher than untreated Ka, whereas high ozone exposed ATD had ice active fractions up to a factor of 4 lower than untreated ATD. From our results, we derive and present parameterizations in terms of ns(T that can be used in models to predict ice nuclei concentrations based on available aerosol surface area.

  18. Model-Free Adaptive Fuzzy Sliding Mode Controller Optimized by Particle Swarm for Robot Manipulator

    Directory of Open Access Journals (Sweden)

    Amin Jalali

    2013-05-01

    Full Text Available The main purpose of this paper is to design a suitable control scheme that confronts the uncertainties in a robot. Sliding mode controller (SMC is one of the most important and powerful nonlinear robust controllers which has been applied to many non-linear systems. However, this controller has some intrinsic drawbacks, namely, the chattering phenomenon, equivalent dynamic formulation, and sensitivity to the noise. This paper focuses on applying artificial intelligence integrated with the sliding mode control theory. Proposed adaptive fuzzy sliding mode controller optimized by Particle swarm algorithm (AFSMC-PSO is a Mamdani’s error based fuzzy logic controller (FLS with 7 rules integrated with sliding mode framework to provide the adaptation in order to eliminate the high frequency oscillation (chattering and adjust the linear sliding surface slope in presence of many different disturbances and the best coefficients for the sliding surface were found by offline tuning Particle Swarm Optimization (PSO. Utilizing another fuzzy logic controller as an impressive manner to replace it with the equivalent dynamic part is the main goal to make the model free controller which compensate the unknown system dynamics parameters and obtain the desired control performance without exact information about the mathematical formulation of model.

  19. On Nonlinear Self-interaction of Geodesic Acoustic Mode Driven By Energetic Particles

    Energy Technology Data Exchange (ETDEWEB)

    G.Y. Fu

    2010-10-01

    It is shown that nonlinear self-interaction of energetic particle-driven Geodesic Acoustic Mode does not generate a second harmonic in radial electric field using the fluid model. However, kinetic effects of energetic particles can induce a second harmonic in the radial electric field. A formula for the second order plasma density perturbation is derived. It is shown that a second harmonic of plasma density perturbation is generated by the convective nonlinearity of both thermal plasma and energetic particles. Near the midplane of a tokamak, the second order plasma density perturbation (the sum of second harmonic and zero frequency sideband) is negative on the low field side with its size comparable to the main harmonic at low fluctuation level. These analytic predictions are consistent with the recent experimental observation in DIII-D.

  20. On Nonlinear Self-interaction of Geodesic Acoustic Mode Driven by Energetic Particles

    Energy Technology Data Exchange (ETDEWEB)

    G. Y. Fu

    2010-06-04

    It is shown that nonlinear self-interaction of energetic particle-driven Geodesic Acoustic Mode does not generate a second harmonic in radial electric field using the fluid model. However, kinetic effects of energetic particles can induce a second harmonic in the radial electric field. A formula for the second order plasma density perturbation is derived. It is shown that a second harmonic of plasma density perturbation is generated by the convective nonlinearity of both thermal plasma and energetic particles. Near the midplane of a tokamak, the second order plasma density perturbation (the sum of second harmonic and zero frequency sideband) is negative on the low field side with its size comparable to the main harmonic at low uctuation level. These analytic predictions are consistent with the recent experimental observation in DIII-D.

  1. Whispering gallery mode single nano-particle detection and sizing: the validity of the dipole approximation

    CERN Document Server

    Foreman, Matthew R; Treasurer, Eshan; Lopez, Jehovani; Arnold, Stephen

    2016-01-01

    Interactions between whispering gallery modes (WGMs) and small nanoparticles are commonly modelled by treating the particle as a point dipole scatterer. This approach is assumed to be accurate as long as the nanoparticle radius, $a$, is small compared to the WGM wavelength $\\lambda$. In this article, however, we show that the large field gradients associated with the evanescent decay of a WGM causes the dipole theory to significantly underestimate the interaction strength, and hence induced WGM resonance shift, even for particles as small as $a\\sim \\lambda/10$. To mitigate this issue we employ a renormalized Born approximation to more accurately determine nanoparticle induced resonance shifts and hence enable improved particle sizing. The domain of validity of this approximation is investigated and supporting experimental results are presented.

  2. Evidence of the dominance of higher-mode surface waves in the lake-bed zone of the Valley of Mexico

    Science.gov (United States)

    Shapiro, N. M.; Singh, S. K.; Almora, D.; Ayala, M.

    2001-12-01

    We compare ground motions recorded at the surface and in boreholes at five different locations of the lake-bed zone of the Valley of Mexico with theoretical dispersion curves and eigenfunctions calculated for the first two modes of Rayleigh and Love waves. We find that (1) the maximum in the horizontal-to-vertical displacement ratio, which occurs at the dominant frequency of the site (0.4Hz), corresponds to the higher mode rather than to the fundamental mode of the Rayleigh waves, (2) borehole records at depths from 0 to 100m show that the normalized vertical displacement does not decrease rapidly below the superficial clay layer, as should be the case for the fundamental mode, but remains ~ 0.8, and (3) the measured phase velocity at a period of about 2.5s (2.0+/-0.5kms-1 ) is too fast for the fundamental mode predicted for the known crustal velocity structure. These observations lead us to conclude that the wavefield in the lake-bed zone in Mexico City is dominated by higher-mode surface waves. This provides a plausible explanation for the long duration of the coda in the lake-bed zone. Although shear wave Q is very small (10-20) in the clay layer, the higher modes of surface waves do not propagate in the superficial clay layer but in the underlying structure where Q -values are likely to be relatively high. Thus, while the clay layer plays the passive role of amplifying the ground motion, its contribution in damping out the motion is insignificant. The results have two important practical implications. (1) The strain estimate from recorded ground velocity differs significantly for the fundamental mode as compared to the higher-mode surface waves. (2) If the ground motion is dominated by the fundamental mode, then knowledge of the superficial layer and the velocity contrast with the underlying structure is sufficient for understanding and modelling of the ground motion. If, however, the higher-mode surface waves dominate, then a detailed knowledge of the deeper

  3. Trapped fast particle destabilization of internal kink mode for the locally flattened q-profile with an inflection point

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xian-Qu [Institute of Fusion Science, School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhang, Rui-Bin; Meng, Guo [State Key Lab of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China)

    2016-07-15

    The destabilization of ideal internal kink modes by trapped fast particles in tokamak plasmas with a “shoulder”-like equilibrium current is investigated. It is found that energetic particle branch of the mode is unstable with the driving of fast-particle precession drifts and corresponds to a precessional fishbone. The mode with a low stability threshold is also more easily excited than the conventional precessional fishbone. This is different from earlier studies for the same equilibrium in which the magnetohydrodynamic (MHD) branch of the mode is stable. Furthermore, the stability and characteristic frequency of the mode are analyzed by solving the dispersion relation and comparing with the conventional fishbone. The results suggest that an equilibrium with a locally flattened q-profile, may be modified by localized current drive (or bootstrap current, etc.), is prone to the onset of the precessional fishbone branch of the mode.

  4. Emission and dry deposition of accumulation mode particles in the Amazon Basin

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2010-11-01

    Full Text Available Size-resolved vertical aerosol number fluxes of particles in the diameter range 0.25–2.5 μm were measured with the eddy covariance method from a 53 m high tower over the Amazon rain forest, 60 km NNW of Manaus, Brazil. This study focuses on data measured during the relatively clean wet season, but a shorter measurement period from the more polluted dry season is used as a comparison.

    Size-resolved net particle fluxes of the five lowest size bins, representing 0.25–0.45 μm in diameter, were in general dominated by deposition in more or less all wind sectors in the wet season. This is an indication that the source of primary biogenic aerosol particles may be small in this particle size range. Transfer velocities within this particle size range were observed to increase linearly with increasing friction velocity and increasing particle diameter.

    In the diameter range 0.5–2.5 μm, vertical particle fluxes were highly dependent on wind direction. In wind sectors where anthropogenic influence was low, net upward fluxes were observed. However, in wind sectors associated with higher anthropogenic influence, deposition fluxes dominated. The net upward fluxes were interpreted as a result of primary biogenic aerosol emission, but deposition of anthropogenic particles seems to have masked this emission in wind sectors with higher anthropogenic influence. The net emission fluxes were at maximum in the afternoon when the mixed layer is well developed, and were best correlated with horizontal wind speed according to the equation

    log10 F=0.48 · U+2.21

    where F is the net emission number flux of 0.5–2.5 μm particles [m−2 s−1] and U is the horizontal wind speed [ms−1] at the top of the tower.

  5. Fluid electron, gyrokinetic ion simulations of linear internal kink and energetic particle modes

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Michael, E-mail: michael.cole@ipp.mpg.de; Mishchenko, Alexey; Könies, Axel; Kleiber, Ralf; Borchardt, Matthias [Max-Planck-Institut für Plasmaphysik, D-17491 Greifswald (Germany)

    2014-07-15

    The internal kink mode is an important plasma instability responsible for a broad class of undesirable phenomena in tokamaks, including the sawtooth cycle and fishbones. To predict and discover ways to mitigate this behaviour in current and future devices, numerical simulations are necessary. The internal kink mode can be modelled by reduced magnetohydrodynamics (MHD). Fishbone modes are an inherently kinetic and non-linear phenomenon based on the n = 1 Energetic Particle Mode (EPM), and have been studied using hybrid codes that combine a reduced MHD bulk plasma model with a kinetic treatment of fast ions. In this work, linear simulations are presented using a hybrid model which couples a fluid treatment of electrons with a gyrokinetic treatment of both bulk and fast ions. Studies of the internal kink mode in geometry relevant to large tokamak experiments are presented and the effect of gyrokinetic ions is considered. Interaction of the kink with gyrokinetic fast ions is also considered, including the destabilisation of the linear n = 1 EPM underlying the fishbone.

  6. The effect of metal transfer modes and shielding gas composition on the emission of ultrafine particles in MAG steel welding

    OpenAIRE

    Gomes, J. F.; R. M. Miranda; Carvalho,P.A.; Quintino,M. L.

    2014-01-01

    The present study aims to characterize ultrafine particles emitted during gas metal arc welding of mild steel and stainless steel, using different shielding gas mixtures, and to evaluate the effect of metal transfer modes, controlled by both processing parameters and shielding gas composition, on the quantity and morphology of the ultrafine particles. It was found that the amount of emitted ultrafine particles (measured by particle number and alveolar deposited surface area) are clearly depen...

  7. Partitioning of Black Carbon between ultrafine and fine particle modes in an urban airport vs. urban background environment

    Science.gov (United States)

    Costabile, F.; Angelini, F.; Barnaba, F.; Gobbi, G. P.

    2015-02-01

    In this work, we characterize the Black Carbon (BC) aerosol in an urban airport vs. urban background environment with the objective to evaluate when and how the ultrafine BC dominates the bulk aerosol. Aerosol optical and microphysical properties were measured in a Mediterranean urban area (Rome) at sites impacted by BC sources including fossil fuels (FF), and biomass burning (BB). Experimental BC data were interpreted through measurement-constrained simulations of BC microphysics and optical properties. A "scheme" to separate the ultrafine BC was experimented on the basis of the relation found between changes in the BC partitioning between Aitken and accumulation mode particles, and relevant changes in particle size distribution and optical properties of the bulk aerosol. This separation scheme, applied to experimental data, proved useful to reveal the impact of airport and road traffic emissions. Findings may have important atmospheric implications. The experimented scheme can help separating different BC sources (FF, BB, "aged" BC) when BC size distributions may be very difficult to obtain (satellite, columnar observations, routine monitoring). Indeed, separating the ultrafine BC from the fine BC may provide significant benefits in addressing BC impact on air quality and climate.

  8. Relationship between the zonal displacement of the western Pacific subtropical high and the dominant modes of low-tropospheric circulation in summer

    Institute of Scientific and Technical Information of China (English)

    Riyu Lu; Ying Li; Chan-Su Ryu

    2008-01-01

    The zonal displacement of the western Pacific subtropical high remarkably influences the climate anomalies in China. In this paper, a new zonal index of the subtropical high is defined by modifying previous indices, and is used to investigate the relationship between the zonal displacement of the subtropical high and the dominant modes of 850-hPa circulations. It is found that the zonal displacement of the subtropical high is significantly correlated with the first two leading modes of circulations. In particular, the correlation coefficient between the index and the time series associated with the second mode is as high as 0.78 in 1958-2003 (46 years). Since the second mode is not associated with significant anomalies of sea surface temperatures, the above results imply the difficulty in seasonal forecasting of the zonal displacement of the subtropical high. In addition, the interannual variability in the zonal displacement of the subtropical high has been considerably enhanced since 1978, due to the effects of both dominant modes, especially the second mode. This is likely to account for the frequent occurrence of anomalous climate in China during the recent two decades.

  9. Temperature-dependent accumulation mode particle and cloud nuclei concentrations from biogenic sources during WACS 2010

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2012-10-01

    Full Text Available Submicron aerosol particles collected simultaneously at the mountain peak (2182 m a.s.l. and at a forested mid-mountain site (1300 m a.s.l. on Whistler Mountain, British Columbia, Canada, during June and July 2010 were analyzed by Fourier transform infrared (FTIR spectroscopy for quantification of organic functional groups. Positive matrix factorization (PMF was applied to the FTIR spectra. Three PMF factors associated with (1 combustion, (2 biogenics, and (3 vegetative detritus, were identified at both sites. The biogenic factor was correlated with both temperature and several volatile organic compounds (VOCs. The combustion factor dominated the submicron particle mass during the beginning of the campaign when the temperature was lower and advection was from the Vancouver area, but as the temperature started to rise in early July the biogenic factor came to dominate as a result of increased emissions of biogenic VOCs and thereby increased formation of secondary organic aerosol (SOA. On average, the biogenic factor represented 69% and 49% of the submicron organic particle mass at Whistler Peak and at the mid-mountain site, respectively. The lower fraction at the mid-mountain site was a result of more vegetative detritus there, and also higher influence from local combustion sources.

    The biogenic factor was strongly correlated (r ~ 0.9 to number concentration of particles with diameter (Dp> 100 nm, whereas the combustion factor was better correlated to number concentration of particles with Dp < 100 nm (r~ 0.4. The number concentration of cloud condensation nuclei (CCN was correlated (r ~ 0.7 to the biogenic factor for supersaturations (S of 0.2% or higher, which indicates that particle condensational growth from biogenic vapors was an important factor in controlling the CCN concentration for clouds where S≥0.2%. Both the number concentration of particles with

  10. Temperature-dependent accumulation mode particle and cloud nuclei concentrations from biogenic sources during WACS 2010

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2013-03-01

    Full Text Available Submicron aerosol particles collected simultaneously at the mountain peak (2182 m a.s.l. and at a forested mid-mountain site (1300 m a.s.l. on Whistler Mountain, British Columbia, Canada, during June and July 2010 were analyzed by Fourier transform infrared (FTIR spectroscopy for quantification of organic functional groups. Positive matrix factorization (PMF was applied to the FTIR spectra. Three PMF factors associated with (1 combustion, (2 biogenics, and (3 vegetative detritus were identified at both sites. The biogenic factor was correlated with both temperature and several volatile organic compounds (VOCs. The combustion factor dominated the submicron particle mass during the beginning of the campaign, when the temperature was lower and advection was from the Vancouver area, but as the temperature started to rise in early July, the biogenic factor came to dominate as a result of increased emissions of biogenic VOCs, and thereby increased formation of secondary organic aerosol (SOA. On average, the biogenic factor represented 69% and 49% of the submicron organic particle mass at Whistler Peak and at the mid-mountain site, respectively. The lower fraction at the mid-mountain site was a result of more vegetative detritus there, and also higher influence from local combustion sources. The biogenic factor was strongly correlated (r~0.9 to number concentration of particles with diameter (Dp> 100 nm, whereas the combustion factor was better correlated to number concentration of particles with Dpr~0.4. The number concentration of cloud condensation nuclei (CCN was correlated (r~0.7 to the biogenic factor for supersaturations (S of 0.2% or higher, which indicates that particle condensational growth from biogenic vapors was an important factor in controlling the CCN concentration for clouds where S≥0.2%. Both the number concentration of particles with Dp>100 nm and numbers of CCN for S≥0.2% were correlated to temperature. Considering the biogenic

  11. Structure of wave-particle resonances and Alfvén mode saturation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Lauber, Ph. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Briguglio, S.; Fusco, V. [C.R. ENEA Frascati - C.P. 65, 00044 Frascati (Italy); Zonca, F. [C.R. ENEA Frascati - C.P. 65, 00044 Frascati (Italy); Institute for Fusion Theory and Simulation and Department of Physics, Zhejiang University Hangzhou 310027 (China)

    2016-01-15

    The dynamics of beta-induced Alfvén eigenmodes driven by anisotropic co-passing or counter-passing fast ions, in a low-shear magnetic equilibrium, is investigated by self-consistent hybrid MHD-particle simulations with the XHMGC code. Though the modes exhibit similar structure and frequency in both cases and the linear growth rate is 10% larger for counter-passing ions than for co-passing ions, the nonlinear saturation amplitude is much larger in co-passing case. Moreover, different scalings for the saturation amplitude with increasing growth rates are observed in the two cases. It is shown that these differences are caused by the different radial dependence of resonance frequencies of co-passing and counter-passing fast ions: flat in the former case, steep in the latter case, so that the resonance width is, respectively, larger (in the former case) or smaller (in the latter case) than the mode width.

  12. Multi-mode Alfv\\'enic Fast Particle Transport and Losses: Numerical vs. Experimental Observation

    CERN Document Server

    Schneller, Mirjam; Bilato, Roberto; García-Muñoz, Manuel; Brüdgam, Michael; Günter, Sibylle

    2013-01-01

    In many discharges at ASDEX Upgrade fast particle losses can be observed due to Alfv\\'enic gap modes, Reversed Shear Alfv\\'en Eigenmodes or core-localized Beta Alfv\\'en Eigenmodes. For the first time, simulations of experimental conditions in the ASDEX Upgrade fusion device are performed for different plasma equilibria (particularly for different, also non-monotonic q profiles). The numerical tool is the extended version of the HAGIS code [Pinches'98, Br\\"udgam PhD Thesis, 2010], which also computes the particle motion in the vacuum region between vessel wall in addition to the internal plasma volume. For this work, a consistent fast particle distribution function was implemented to represent the strongly anisotropic fast particle population as generated by ICRH minority heating. Furthermore, HAGIS was extended to use more realistic eigenfunctions, calculated by the gyrokinetic eigenvalue solver LIGKA [Lauber'07]. The main aim of these simulations is to allow fast ion loss measurements to be interpreted with ...

  13. Mapping out spin and particle conductances of a single-mode channel with tunable interactions

    Science.gov (United States)

    Lebrat, Martin; Krinner, Sebastian; Grenier, Charles; Husmann, Dominik; Häusler, Samuel; Nakajima, Shuta; Brantut, Jean-Philippe; Esslinger, Tilman

    2016-05-01

    We study particle and spin transport in a single-mode quantum point contact, shaped by light potentials onto a charge neutral, quantum degenerate gas of 6 Li fermions with tunable interactions. The spin and particle conductances are measured as a function of chemical potential or confinement, covering weak attraction, where quantized conductance is observed, to the strongly interacting superfluid regime. Spin conductance exhibits a broad maximum when varying the chemical potential at moderate interactions, which signals the emergence of superfluidity. In contrast, the particle conductance is unexpectedly enhanced even before the gas is expected to turn into a superfluid: it shows conductance plateaus at non-universal values continuously increasing from 1/h to 4/h, as the interaction strength is increased from weak to intermediate. For strong interactions, the particle conductance plateaus disappear and the spin conductance gets suppressed, confirming the spin-insulating character of a superfluid. Our observations document the breakdown of universal conductance quantization as many-body correlations appear. This anomalous quantization is incompatible with a Fermi liquid description, shedding new light on the nature of the strongly attractive Fermi gas in the normal phase.

  14. Profiling of fine- and coarse-mode particles with LIRIC (LIdar/Radiometer Inversion Code

    Directory of Open Access Journals (Sweden)

    M. R. Perrone

    2014-08-01

    Full Text Available The paper investigates numerical procedures that allow determining the dependence on altitude of aerosol properties from multi wavelength elastic lidar signals. In particular, the potential of the LIdar/Radiometer Inversion Code (LIRIC to retrieve the vertical profiles of fine and coarse-mode particles by combining 3-wavelength lidar measurements and collocated AERONET (AErosol RObotic NETwork sun/sky photometer measurements is investigated. The used lidar signals are at 355, 532 and 1064 nm. Aerosol extinction coefficient (αL, lidar ratio (LRL, and Ångstrom exponent (ÅL profiles from LIRIC are compared with the corresponding profiles (α, LR, and Å retrieved from a Constrained Iterative Inversion (CII procedure to investigate the LIRIC retrieval ability. Then, an aerosol classification framework which relies on the use of a graphical framework and on the combined analysis of the Ångstrom exponent (at the 355 and 1064 nm wavelength pair, Å(355, 1064 and its spectral curvature (ΔÅ = Å(355, 532–Å(532, 1064 is used to investigate the ability of LIRIC to retrieve vertical profiles of fine and coarse-mode particles. The Å-ΔÅ aerosol classification framework allows estimating the dependence on altitude of the aerosol fine modal radius and of the fine mode contribution to the whole aerosol optical thickness, as discussed in Perrone et al. (2014. The application of LIRIC to three different aerosol scenarios dealing with aerosol properties dependent on altitude has revealed that the differences between αL and α vary with the altitude and on average increase with the decrease of the lidar signal wavelength. It has also been found that the differences between ÅL and corresponding Å values vary with the altitude and the wavelength pair. The sensitivity of Ångstrom exponents to the aerosol size distribution which vary with the wavelength pair was responsible for these last results. The aerosol classification framework has revealed that

  15. The Herschel view of the dominant mode of galaxy growth from z = 4 to the present day

    Science.gov (United States)

    Schreiber, C.; Pannella, M.; Elbaz, D.; Béthermin, M.; Inami, H.; Dickinson, M.; Magnelli, B.; Wang, T.; Aussel, H.; Daddi, E.; Juneau, S.; Shu, X.; Sargent, M. T.; Buat, V.; Faber, S. M.; Ferguson, H. C.; Giavalisco, M.; Koekemoer, A. M.; Magdis, G.; Morrison, G. E.; Papovich, C.; Santini, P.; Scott, D.

    2015-03-01

    our findings on the cosmic SFR history and on the origin of present-day stars: more than two-thirds of present-day stars must have formed in a regime dominated by the "main sequence" mode. As a consequence we conclude that, although omnipresent in the distant Universe, galaxy mergers had little impact in shaping the global star formation history over the last 12.5 billion years. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendices are available in electronic form at http://www.aanda.org

  16. An Extraction of the Dominant Rotor-Stator Interaction Modes by the Use of Proper Orthogonal Decomposition (POD)

    Institute of Scientific and Technical Information of China (English)

    I. TREBINJAC; N. ROCHUON; G. BILLONNET

    2006-01-01

    The Proper Orthogonal Decomposition method is applied to the instantaneous velocity field within the rotor-stator inter-row region of a high-speed high-pressure centrifugal compressor. The processed data come from experiments and numerical simulations. In comparison with a Fourier transform, the POD gives the best modal approximation for both initial fields, in terms of the energy expressed on any given number of modes to be taken into account: to reach 98% of the total energy of the velocity field, the required number of POD modes is around nine times smaller than the number of Fourier harmonics. The individual POD modes are given and show that the unsteady rotor-stator interaction is already present in the very first modes.

  17. Higher order mode excitation in eccentric active nano-particles for tailoring of the near-field radiation

    DEFF Research Database (Denmark)

    Thorsen, R. O.; Arslanagic, Samel

    2015-01-01

    We examine the excitation of resonant modes inside eccentrically layered cylindrical active nano-particles. The nano-particle is a three-layer structure comprised of a silica core, a free-space middle layer, and an outer shell of silver. It is shown that a concentric configuration, initially desi...

  18. Two dominant modes of winter temperature variations over China and their relationships with large-scale circulations in CMIP5 models

    Science.gov (United States)

    Guo, Yan; Zhao, Zongci; Dong, Wenjie

    2016-05-01

    In this paper, we analyze the two dominant modes of winter surface air temperature (SAT) variations over China and their relationships with large-scale circulation anomalies. We then examine the fidelities of 20 individual models participating in the Coupled Model Inter-comparison Project Phase 5 in reproducing these two perspectives. Results showed that the winter SAT variations over China are dominated by two modes, a homogeneous warming pattern and a tripole pattern with warm departure in Northwest and Northeast China and cold departure in central and southern China. Consistent with the previous studies which documented the variations of the two modes are associated with the Siberian high and Arctic Oscillation (AO) anomalies, respectively, it is newly found that the variation of Empirical Orthogonal Function 2 (EOF2) mode is associated with the Northwest Pacific south-north dipole sea surface temperature anomaly in addition to the AO anomaly. Through comparisons with the observations, we identified that eight models outperform the others in simulating the two dominant modes and their relationships with large-scale circulation anomalies. These high-performing models were then selected to project future winter SAT changes over China under the Representative Concentration Pathway 4.5 (RCP4.5) scenario. Based on the multi-model ensemble mean, a nationwide warming was projected relative to the present climatology (1970-1999), with the largest increase in the Tibetan Plateau of 1.45 ± 0.62 °C by the period 2010-2039 and 2.87 ± 0.82 °C by the period 2050-2079; followed by Northeast China, Northwest China, North China, East China, Southwest China, and, finally, Southeast China.

  19. Helical-mode magnetostatic resonances in small ferrite particles and singular metamaterials.

    Science.gov (United States)

    Kamenetskii, E O

    2010-12-08

    Small ferrite-disk particles with magnetostatic (magneto-dipole) oscillations are characterized by the topological-phase states-the vortex states. In a recently published paper (Kamenetskii et al 2010 Phys. Rev. A 81 053823), it was shown that such magnetic vortices act as traps, providing purely subwavelength confinement of electromagnetic fields. The symmetry properties of magnetostatic-vortex ferrite disks allow one to propose new-type subwavelength microwave structures. In this paper it is demonstrated that the unique topological properties of the fields in a ferrite disk are intimately related to the symmetry breaking effects of magnetostatic oscillations. This analysis is based on postulates about a physical meaning of the magnetostatic-potential function ψ(r, t) as a complex scalar wavefunction, which presumes a long-range phase coherence in magnetic dipole-dipole interactions. The proper solutions are found based on an analysis of magnetostatic-wave propagation in a helical coordinate system. It is shown that while a composition of two helical waves may acquire a geometrical phase over-running of 2π during a period, every separate helical wave has a dynamical phase over-running of π and so behaves as a double-valued function. This results in the appearance of helical-mode magnetostatic resonances in quasi-2D ferrite disks. The solutions give magnetostatic-wave power-flow-density vortices with cores at the disk center and azimuthally running waves of magnetization. The near fields of magnetostatic-vortex ferrite-disk particles are characterized by space-time symmetry violation. For incident electromagnetic waves, such particles, with sizes much less than the free-space electromagnetic wavelength, appear as local singular regions. From the properties of a composition of magnetostatic-vortex ferrite-disk particles, one may propose novel metamaterials-singular metamaterials.

  20. Characterization of satellite based proxies for estimating nucleation mode particles over South Africa

    Directory of Open Access Journals (Sweden)

    A.-M. Sundström

    2014-10-01

    Full Text Available In this work satellite observations from the NASA's A-Train constellation were used to derive the values of primary emission and regional nucleation proxies over South Africa to estimate the potential for new particle formation. As derived in Kulmala et al. (2011, the satellite based proxies consist of source terms (NO2, SO2 and UV-B radiation, and a sink term describing the pre-existing aerosols. The first goal of this work was to study in detail the use of satellite aerosol optical depth (AOD as a substitute to the in situ based condensation sink (CS. One of the major factors affecting the agreement of CS and AOD was the elevated aerosol layers that increased the value of column integrated AOD but not affected the in situ CS. However, when the AOD in the proxy sink was replaced by an estimate from linear bivariate fit between AOD and CS, the agreement with the actual nucleation mode number concentration improved somewhat. The second goal of the work was to estimate how well the satellite based proxies can predict the potential for new particle formation. For each proxy the highest potential for new particle formation were observed over the Highveld industrial area, where the emissions were high but the sink due to pre-existing aerosols was relatively low. Best agreement between the satellite and in situ based proxies were obtained for NO2/AOD and UV-B/AOD2, whereas proxies including SO2 in the source term had lower correlation. Even though the OMI SO2 boundary layer product showed reasonable spatial pattern and detected the major sources over the study area, some of the known minor point sources were not detected. When defining the satellite proxies only for days when new particle formation event was observed, it was seen that for all the satellite based proxies the event day medians were higher than the entire measurement period median.

  1. On the ordinary mode Weibel instability in space plasmas: A comparison of three-particle distributions

    Science.gov (United States)

    Rubab, Nazish; Chian, Abraham C.-L.; Jatenco-Pereira, Vera

    2016-03-01

    Electromagnetic wave fluctuations driven by temperature anisotropy in plasmas are of interest for solar flare, solar corona, and solar wind studies. We investigate the dispersion characteristics of electromagnetic wave propagating perpendicular to the uniform magnetic field which is derived by using multiple particle distribution functions: Maxwellian, bi-kappa, and product bi-kappa. The presence of temperature anisotropy in which the parallel plasma kinetic energy density exceeding by a sufficient amount can lead to Weibel-like electromagnetic instability. A general description is made to calculate the growth/damping rates of Weibel-like modes when the temperature anisotropy and nonthermal features are associated with these distributions. We demonstrate that for the zeroth cyclotron harmonic, our results for bi-Maxwellian and bi-kappa overlap with each other, while the product bi-kappa distribution shows some dependence on parallel kappa index. For higher harmonics, the growth rates vanish and the damping prevails.

  2. Travel Mode Detection Based on Neural Networks and Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Guangnian Xiao

    2015-08-01

    Full Text Available The collection of massive Global Positioning System (GPS data from travel surveys has increased exponentially worldwide since the 1990s. A number of methods, which range from rule-based to advanced classification approaches, have been applied to detect travel modes from GPS positioning data collected in travel surveys based on GPS-enabled smartphones or dedicated GPS devices. Among these approaches, neural networks (NNs are widely adopted because they can extract subtle information from training data that cannot be directly obtained by human or other analysis techniques. However, traditional NNs, which are generally trained by back-propagation algorithms, are likely to be trapped in local optimum. Therefore, particle swarm optimization (PSO is introduced to train the NNs. The resulting PSO-NNs are employed to distinguish among four travel modes (walk, bike, bus, and car with GPS positioning data collected through a smartphone-based travel survey. As a result, 95.81% of samples are correctly flagged for the training set, while 94.44% are correctly identified for the test set. Results from this study indicate that smartphone-based travel surveys provide an opportunity to supplement traditional travel surveys.

  3. Particle and heat flux estimates in Proto-MPEX in Helicon Mode with IR imaging

    Science.gov (United States)

    Showers, M. A.; Biewer, T. M.; Caughman, J. B. O.; Donovan, D. C.; Goulding, R. H.; Rapp, J.

    2016-10-01

    The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) at Oak Ridge National Laboratory (ORNL) is a linear plasma device developing the plasma source concept for the Material Plasma Exposure eXperiment (MPEX), which will address plasma material interaction (PMI) science for future fusion reactors. To better understand how and where energy is being lost from the Proto-MPEX plasma during ``helicon mode'' operations, particle and heat fluxes are quantified at multiple locations along the machine length. Relevant diagnostics include infrared (IR) cameras, four double Langmuir probes (LPs), and in-vessel thermocouples (TCs). The IR cameras provide temperature measurements of Proto-MPEX's plasma-facing dump and target plates, located on either end of the machine. The change in surface temperature is measured over the duration of the plasma shot to determine the heat flux hitting the plates. The IR cameras additionally provide 2-D thermal load distribution images of these plates, highlighting Proto-MPEX plasma behaviors, such as hot spots. The LPs and TCs provide additional plasma measurements required to determine particle and heat fluxes. Quantifying axial variations in fluxes will help identify machine operating parameters that will improve Proto-MPEX's performance, increasing its PMI research capabilities. This work was supported by the U.S. D.O.E. contract DE-AC05-00OR22725.

  4. An alpha particle instrument with alpha, proton, and X-ray modes for planetary chemical analyses

    Science.gov (United States)

    Economou, T. E.; Turkevich, A. L.

    1976-01-01

    The interaction of alpha particles with matter is employed in a compact instrument that could provide rather complete in-situ chemical analyses of surfaces and thin atmospheres of extraterrestrial bodies. The instrument is a miniaturized and improved version of the Surveyor lunar instrument. The backscattering of alpha particles and (alpha, p) reactions provide analytical data on the light elements (carbon-iron). An X-ray mode that detects the photons produced by the alpha sources provides sensitivity and resolution for the chemical elements heavier than about silicon. The X-rays are detected by semiconductor detectors having a resolution between 150 and 250 eV at 5.9 keV. Such an instrument can identify and determine with good accuracy 99 percent of the atoms (except hydrogen) in rocks. For many trace elements, the detecting sensitivity is a few ppm. Auxiliary sources could be used to enhance the sensitivities for elements of special interest. The instrument could probably withstand the acceleration involved in semi-hard landings.

  5. Using graphene nano-particle embedded in photonic crystal fiber for evanescent wave mode-locking of fiber laser.

    Science.gov (United States)

    Lin, Yung-Hsiang; Yang, Chun-Yu; Liou, Jia-Hong; Yu, Chin-Ping; Lin, Gong-Ru

    2013-07-15

    A photonic crystal fiber (PCF) with high-quality graphene nano-particles uniformly dispersed in the hole cladding are demonstrated to passively mode-lock the erbium-doped fiber laser (EDFL) by evanescent-wave interaction. The few-layer graphene nano-particles are obtained by a stabilized electrochemical exfoliation at a threshold bias. These slowly and softly exfoliated graphene nano-particle exhibits an intense 2D band and an almost disappeared D band in the Raman scattering spectrum. The saturable phenomena of the extinction coefficient β in the cladding provides a loss modulation for the intracavity photon intensity by the evanescent-wave interaction. The evanescent-wave mode-locking scheme effectively enlarges the interaction length of saturable absorption with graphene nano-particle to provide an increasing transmittance ΔT of 5% and modulation depth of 13%. By comparing the core-wave and evanescent-wave mode-locking under the same linear transmittance, the transmittance of the graphene nano-particles on the end-face of SMF only enlarges from 0.54 to 0.578 with ΔT = 3.8% and the modulation depth of 10.8%. The evanescent wave interaction is found to be better than the traditional approach which confines the graphene nano-particles at the interface of two SMF patchcords. When enlarging the intra-cavity gain by simultaneously increasing the pumping current of 980-nm and 1480-nm pumping laser diodes (LDs) to 900 mA, the passively mode-locked EDFL shortens its pulsewidth to 650 fs and broadens its spectral linewidth to 3.92 nm. An extremely low carrier amplitude jitter (CAJ) of 1.2-1.6% is observed to confirm the stable EDFL pulse-train with the cladding graphene nano-particle based evanescent-wave mode-locking.

  6. Influence of Ba2+ and Pb2+ Ions on the Raman Dominating Active Vibronic Mode in Strontium Nitrate Crystals

    Institute of Scientific and Technical Information of China (English)

    李超荣; 吴立军; 陈万春

    2002-01-01

    The compositions of Sr(NO3)2 crystals grown from an aqueous solution doped with Ba2+ and Pb2+ were characterized by the electron probe microanalysis technique. It was found that Ba2+ is enriched in {100} sectors and Pb2+ in { 111} sectors. The Raman spectra of different parts of these crystals at room temperature in the ranges of 1038 - 1070cm-1 and 650 - 1150 cm-1 were investigated. The results indicated that barium and lead shift the Raman dominating peaks to the lower frequency and broaden the full width at half maximum. Furthermore,barium probably degrades the properties of the Sr(NOa)2 Raman shifter while lead is anticipated to improve it.

  7. Measurement of electron particle transport coefficients in different operational modes of DIII-D

    Science.gov (United States)

    Baker, D. R.; Wade, M. R.; Jackson, G. L.; Maingi, R.; Stockdale, R. E.; de Grassie, J. S.; Groebner, R. J.; Forest, C. B.; Porter, G. D.; DIII-D Team

    1998-04-01

    Electron transport coefficients have been obtained for different operational modes on the DIII-D tokamak. The operational modes are: double null diverted (DND) low confinement (L mode), DND high confinement (H mode) without edge localized modes (ELM-free), single null diverted (SND) ELM-free H mode and pumped SND ELMing H mode. Various values of plasma current and safety factor (q) profiles were investigated. For the L mode and ELMing H mode, the coefficients were obtained by a modulated puff of deuterium gas at the edge. For the ELM-free modes, the coefficients were obtained by analysing the temporal evolution of the electron density profile immediately after the L-H transition. The results show clearly that the radial profile of the electron diffusion coefficient depends on the operational mode of DIII-D. The difference in the radial dependences of the transport coefficients between the different tokamak operational modes is significant. In the L mode and the ELMing H mode, the diffusion coefficient increases with radius. In ELMing H mode, the diffusion coefficient increases with the edge value of q. The value at the edge for L mode is about twice that for ELMing H mode. In ELM-free H mode, the diffusion coefficient decreases rapidly outside a normalized radius of about 0.8. Within the (relatively large) error bars for ELM-free H mode, there is no measurable difference in diffusion coefficient between the DND and SND plasmas.

  8. An energy-conserving, particle dominated, time-dependent model of 3C58 and its observability at high-energies

    CERN Document Server

    Torres, Diego F; Rodriguez, Jonatan Martin

    2012-01-01

    We present a time-dependent spectral model of the nebula 3C58 and compare it with available data. The model is for a leptonic nebula, in which particles are subject to synchrotron, inverse Compton, self-synchrotron Compton, adiabatic, and bremsstrahlung processes. We find that 3C58 is compatible with being a particle dominated nebula, with a magnetic field of 35$\\mu$G. A broken power law injection fits well the multi-frequency data, with a break energy at about 40 GeV. We find that 3C58 is not expected to appear in VERITAS or MAGIC II, unless the local IR background is a factor of \\sim20 off Galactic models averages. For cases in which the CMB dominates the inverse Compton contribution, we find that 3C58 will not be visible either for the Cherenkov Telescope Array.

  9. AN ENERGY-CONSERVING, PARTICLE-DOMINATED, TIME-DEPENDENT MODEL OF 3C 58 AND ITS OBSERVABILITY AT HIGH ENERGIES

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Diego F.; Martin Rodriguez, Jonatan [Institute of Space Sciences (IEEC-CSIC), Campus UAB, Torre C5, 2a planta, E-08193 Barcelona (Spain); Cillis, Analia N. [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67-Suc. 28 (C1428ZAA), Buenos Aires (Argentina)

    2013-01-20

    We present a time-dependent spectral model of the nebula 3C 58 and compare it with available data. The model is for a leptonic nebula in which particles are subject to synchrotron, inverse Compton, self-synchrotron Compton, adiabatic, and bremsstrahlung processes. We find that 3C 58 is compatible with being a particle-dominated nebula, with a magnetic field of 35 {mu}G. A broken power-law injection fits well the multi-frequency data, with a break energy at about 40 GeV. We find that 3C 58 is not expected to appear in VERITAS or MAGIC II, unless the local IR background is a factor of {approx}20 off Galactic models' averages. For cases in which the cosmic microwave background dominates the inverse Compton contribution, we find that 3C 58 will not be visible either for the Cherenkov Telescope Array.

  10. Automation and heat transfer characterization of immersion mode spectroscopy for analysis of ice nucleating particles

    Science.gov (United States)

    Beall, Charlotte M.; Stokes, M. Dale; Hill, Thomas C.; DeMott, Paul J.; DeWald, Jesse T.; Prather, Kimberly A.

    2017-07-01

    Ice nucleating particles (INPs) influence cloud properties and can affect the overall precipitation efficiency. Developing a parameterization of INPs in global climate models has proven challenging. More INP measurements - including studies of their spatial distribution, sources and sinks, and fundamental freezing mechanisms - must be conducted in order to further improve INP parameterizations. In this paper, an immersion mode INP measurement technique is modified and automated using a software-controlled, real-time image stream designed to leverage optical changes of water droplets to detect freezing events. For the first time, heat transfer properties of the INP measurement technique are characterized using a finite-element-analysis-based heat transfer simulation to improve accuracy of INP freezing temperature measurement. The heat transfer simulation is proposed as a tool that could be used to explain the sources of bias in temperature measurements in INP measurement techniques and ultimately explain the observed discrepancies in measured INP freezing temperatures between different instruments. The simulation results show that a difference of +8.4 °C between the well base temperature and the headspace gas results in an up to 0.6 °C stratification of the aliquot, whereas a difference of +4.2 °C or less results in a thermally homogenous water volume within the error of the thermal probe, ±0.2 °C. The results also show that there is a strong temperature gradient in the immediate vicinity of the aliquot, such that without careful placement of temperature probes, or characterization of heat transfer properties of the water and cooling environment, INP measurements can be biased toward colder temperatures. Based on a modified immersion mode technique, the Automated Ice Spectrometer (AIS), measurements of the standard test dust illite NX are reported and compared against six other immersion mode droplet assay techniques featured in Hiranuma et al. (2015) that used

  11. How to reliably detect molecular clusters and nucleation mode particles with Neutral cluster and Air Ion Spectrometer (NAIS)

    Science.gov (United States)

    Manninen, Hanna E.; Mirme, Sander; Mirme, Aadu; Petäjä, Tuukka; Kulmala, Markku

    2016-08-01

    To understand the very first steps of atmospheric particle formation and growth processes, information on the size where the atmospheric nucleation and cluster activation occurs, is crucially needed. The current understanding of the concentrations and dynamics of charged and neutral clusters and particles is based on theoretical predictions and experimental observations. This paper gives a standard operation procedure (SOP) for Neutral cluster and Air Ion Spectrometer (NAIS) measurements and data processing. With the NAIS data, we have improved the scientific understanding by (1) direct detection of freshly formed atmospheric clusters and particles, (2) linking experimental observations and theoretical framework to understand the formation and growth mechanisms of aerosol particles, and (3) parameterizing formation and growth mechanisms for atmospheric models. The SOP provides tools to harmonize the world-wide measurements of small clusters and nucleation mode particles and to verify consistent results measured by the NAIS users. The work is based on discussions and interactions between the NAIS users and the NAIS manufacturer.

  12. Spatial-temporal variations of dominant drought/flood modes and the associated atmospheric circulation and ocean events in rainy season over the east of China

    Science.gov (United States)

    Huang, Shaoni; Huang, Fei

    2012-06-01

    By using Season-reliant Empirical Orthogonal Function (S-EOF) analysis, three dominant modes of the spatial-temporal evolution of the drought/flood patterns in the rainy season over the east of China are revealed for the period of 1960-2004. The first two leading modes occur during the turnabout phase of El Niño-Southern Oscillation (ENSO) decaying year, but the drought/flood patterns in the rainy season over the east of China are different due to the role of the Indian Ocean (IO). The first leading mode appears closely correlated with the ENSO events. In the decaying year of El Niño, the associated western North Pacific (WNP) anticyclone located over the Philippine Sea persists from the previous winter to the next early summer, transports warm and moist air toward the southern Yangtze River in China, and leads to wet conditions over this entire region. Therefore, the precipitation anomaly in summer exhibits a `Southern Flood and Northern Drought' pattern over East China. On the other hand, the basin-wide Indian Ocean sea surface temperature anomaly (SSTA) plays a crucial role in prolonging the impact of ENSO on the second mode during the ENSO decaying summer. The Indian Ocean basin mode (IOBM) warming persists through summer and unleashes its influence, which forces a Matsuno-Gill pattern in the upper troposphere. Over the subtropical western North Pacific, an anomalous anticyclone forms in the lower troposphere. The southerlies on the northwest flank of this anticyclone increase the moisture transport onto central China, leading to abundant rainfall over the middle and lower reaches of the Yangtze River and Huaihe River valleys. The anomalous anticyclone causes dry conditions over South China and the South China Sea (SCS). The precipitation anomaly in summer exhibits a `Northern Flood and Southern Drought' pattern over East China. Therefore, besides the ENSO event the IOBM is an important factor to influence the drought/flood patterns in the rainy season over

  13. The implicit contribution of slab modes to the perpendicular diffusion coefficient of particles interacting with two-component turbulence

    CERN Document Server

    Shalchi, Andreas

    2016-01-01

    We explore the transport of energetic particles in two-component turbulence in which the stochastic magnetic field is assumed to be a superposition of slab and two-dimensional modes. It is known that in magnetostatic slab turbulence, the motion of particles across the mean magnetic field is subdiffusive. If a two-dimensional component is added, diffusion is recovered. It was also shown before that in two-component turbulence, the slab modes do not explicitly contribute to the perpendicular diffusion coefficient. In the current paper the implicit contribution of slab modes is explored and it is shown that this contribution leads to a reduction of the perpendicular diffusion coefficient. This effect improves the agreement between simulations and analytical theory. Furthermore, the obtained results are relevant for investigations of diffusive shock acceleration.

  14. Thermomechanically coupled conduction mode laser welding simulations using smoothed particle hydrodynamics

    Science.gov (United States)

    Hu, Haoyue; Eberhard, Peter

    2016-10-01

    Process simulations of conduction mode laser welding are performed using the meshless Lagrangian smoothed particle hydrodynamics (SPH) method. The solid phase is modeled based on the governing equations in thermoelasticity. For the liquid phase, surface tension effects are taken into account to simulate the melt flow in the weld pool, including the Marangoni force caused by a temperature-dependent surface tension gradient. A non-isothermal solid-liquid phase transition with the release or absorption of additional energy known as the latent heat of fusion is considered. The major heat transfer through conduction is modeled, whereas heat convection and radiation are neglected. The energy input from the laser beam is modeled as a Gaussian heat source acting on the initial material surface. The developed model is implemented in Pasimodo. Numerical results obtained with the model are presented for laser spot welding and seam welding of aluminum and iron. The change of process parameters like welding speed and laser power, and their effects on weld dimensions are investigated. Furthermore, simulations may be useful to obtain the threshold for deep penetration welding and to assess the overall welding quality. A scalability and performance analysis of the implemented SPH algorithm in Pasimodo is run in a shared memory environment. The analysis reveals the potential of large welding simulations on multi-core machines.

  15. Energetic particle driven geodesic acoustic mode in a toroidally rotating tokamak plasma

    Science.gov (United States)

    Ren, Haijun

    2017-01-01

    Energetic particle (EP) driven geodesic acoustic modes (EGAMs) in toroidally rotating tokamak plasmas are analytically investigated using the hybrid kinetic-fluid model and gyrokinetic equations. By ignoring high-order terms and ion Landau damping, the kinetic dispersion relation is reduced to the hybrid one in the large safety factor limit. There is one high-frequency branch with a frequency larger than {ωt0} , the transit frequency of EPs with initial energy, which is always stable. Two low-frequency solutions with a frequency smaller than {ωt0} are complex conjugates in the hybrid limit. In the presence of ion Landau damping, the growth rate of the unstable branch is decreased and the damping rate of the damped branch is increased. The toroidal Mach number is shown to increase {{ Ω }\\text{r}} , the normalized real frequency of both branches. Although not affecting the instability critical condition, the Mach number decreases the growth rate when {{ Ω }\\text{r}} is larger than a critical value Ω \\text{r}\\text{cri} and enlarges the growth rate when {{ Ω }\\text{r}}Landau damping effect is negligible for large M. But the discrepancy between the kinetic dispersion relation and the hybrid one becomes ignorable only for q≳ 7 .

  16. Target particle and heat loads in low-triangularity L-mode plasmas in JET with carbon and beryllium/tungsten walls

    Energy Technology Data Exchange (ETDEWEB)

    Groth, M., E-mail: mathias.groth@aalto.fi [Aalto University, Association EURATOM-Tekes, Espoo (Finland); Brezinsek, S. [Institute for Energy and Climate Research, Association EURATOM-FZJ Jülich (Germany); Belo, P. [Institute of Plasmas and Nuclear Fusion, Association EURATOM-IST, Lisbon (Portugal); Corrigan, G. [Culham Centre of Fusion Energy, EURATOM-Association, Culham Science Centre, Abingdon (United Kingdom); Harting, D.; Wiesen, S. [Institute for Energy and Climate Research, Association EURATOM-FZJ Jülich (Germany); Beurskens, M.N.A.; Brix, M. [Culham Centre of Fusion Energy, EURATOM-Association, Culham Science Centre, Abingdon (United Kingdom); Clever, M.; Coenen, J.W. [Institute for Energy and Climate Research, Association EURATOM-FZJ Jülich (Germany); Eich, T. [Max-Planck Institute for Plasma Physics, EURATOM-Association, Garching (Germany); Flanagan, J.; Giroud, C. [Culham Centre of Fusion Energy, EURATOM-Association, Culham Science Centre, Abingdon (United Kingdom); Huber, A. [Institute for Energy and Climate Research, Association EURATOM-FZJ Jülich (Germany); Jachmich, S. [Association “EURATOM Belgium State”, Laboratory for Plasma Physics, Brussels (Belgium); Kruezi, U.; Lehnen, M. [Institute for Energy and Climate Research, Association EURATOM-FZJ Jülich (Germany); Lowry, C. [EFDA Close Support Unit, Culham Science Centre, Abingdon (United Kingdom); Maggi, C.F. [Max-Planck Institute for Plasma Physics, EURATOM-Association, Garching (Germany); Marsen, S. [Max-Planck-Institut for Plasma Physics, EURATOM-Association, Greifswald (Germany); and others

    2013-07-15

    Divertor radiation profiles, and power and particle fluxes to the target have been measured in attached JET L-mode plasmas with carbon and beryllium/tungsten wall materials. In the beryllium/tungsten configuration, factors of 2–3 higher power loads and peak temperatures at the low field side target were observed in high-recycling scrape-off layer conditions, whilst in close-to-sheath-limited conditions almost identical plasmas were obtained. The 30% reduction in total radiation with the beryllium/tungsten wall is consistent with a reduction of carbon as the dominant impurity radiator; however similar ion current to the plates, emission from recycling neutrals and neutral pressures in the pumping plenum were measured. Simulations with the EDGDE2/EIRENE code of these plasmas indicate a reduction of the total divertor radiation when carbon is omitted, but significantly higher power loads in high-recycling and detached conditions are predicted than measured.

  17. Exposure to ultrafine particles in different transport modes in the city of Rome.

    Science.gov (United States)

    Grana, Mario; Toschi, Nicola; Vicentini, Laura; Pietroiusti, Antonio; Magrini, Andrea

    2017-09-01

    There is evidence of adverse health impacts from human exposure to particulate air pollution, including increased rates of respiratory and cardiovascular illness, hospitalizations, and pre-mature mortality. Most recent hypotheses assign an important role to ultrafine particles (UFP) (exposure to harmful pollutants which occurs during urban travelling. In this context, the aim of this work was to examine the relative contribution of different transport modes to total daily exposure. We performed experimental measurements during both morning and evening traffic peak hours throughout the winter season (December 2013-March 2014), for a total of 98 trips. Our results suggest that the lowest UFP exposures are experienced by underground train commuters, with an average number concentration of 14 134 cm(-3), and are largely a reflection of the routes being at greater distance from vehicular traffic. Motorcyclists experienced significantly higher average concentrations (73 168 cm(-3)) than all other exposure classes, and this is most likely a result of the presence of high-concentration and short-duration peaks which do not occur when the same routes are traveled by car. UFP concentrations in subway train environments were found to be comparable to urban background levels. Still, in underground trains we found the highest values of PM10 mass concentration with a maximum value of 422 μg/m(3). PM10 concentration in trains was found to be four and two times higher than what was measured in car and motorbike trips, respectively. Transport mode contribution to total integrated UFP daily exposure was found to be 16.3%-20.9% while travelling by car, 28.7% for motorbike trips, and 8.7% for subway trips. Due to lower exposure times, commuting by car and motorbike is comparable to other daily activities in terms of exposure. Our data can provide relevant information for transport decision-making and increase environmental awareness in the hope that the information about inhaled

  18. Fano-like resonance emerging from magnetic and electric plasmon mode coupling in small arrays of gold particles

    Science.gov (United States)

    Bakhti, Saïd; Tishchenko, Alexandre V.; Zambrana-Puyalto, Xavier; Bonod, Nicolas; Dhuey, Scott D.; Schuck, P. James; Cabrini, Stefano; Alayoglu, Selim; Destouches, Nathalie

    2016-09-01

    In this work we theoretically and experimentally analyze the resonant behavior of individual 3 × 3 gold particle oligomers illuminated under normal and oblique incidence. While this structure hosts both dipolar and quadrupolar electric and magnetic delocalized modes, only dipolar electric and quadrupolar magnetic modes remain at normal incidence. These modes couple into a strongly asymmetric spectral response typical of a Fano-like resonance. In the basis of the coupled mode theory, an analytical representation of the optical extinction in terms of singular functions is used to identify the hybrid modes emerging from the electric and magnetic mode coupling and to interpret the asymmetric line profiles. Especially, we demonstrate that the characteristic Fano line shape results from the spectral interference of a broad hybrid mode with a sharp one. This structure presents a special feature in which the electric field intensity is confined on different lines of the oligomer depending on the illumination wavelength relative to the Fano dip. This Fano-type resonance is experimentally observed performing extinction cross section measurements on arrays of gold nano-disks. The vanishing of the Fano dip when increasing the incidence angle is also experimentally observed in accordance with numerical simulations.

  19. Quantitative fluorescent in-situ hybridization: a hypothesized competition mode between two dominant bacteria groups in hydrogen-producing anaerobic sludge processes.

    Science.gov (United States)

    Huang, C-L; Chen, C-C; Lin, C-Y; Liu, W-T

    2009-01-01

    Two hydrogen-producing continuous flow stirred tank reactors (CSTRs) fed respectively with glucose and sucrose were investigated by polymerase chain reaction-denatured gradient gel electrophoresis (PCR-DGGE) and fluorescent in-situ hybridization (FISH). The substrate was fed in a continuous mode decreased from hydraulic retention time (HRT) 10 hours to 6, 5, 4, 3, and 2 hours. Quantitative fluorescent in-situ hybridization (FISH) observations further demonstrated that two morphotypes of bacteria dominated both microbial communities. One was long rod bacteria which can be targeted either by Chis150 probe designed to hybridize the gram positive low G + C bacteria or the specific oligonucleotide probe Lg10-6. The probe Lg10-6, affiliated with Clostridium pasteurianum, was designed and then checked with other reference organisms. The other type, unknown group, which cannot be detected by Chis150 was curved rod bacteria. Notably, the population ratios of the two predominant groups reflected the different operational performance of the two reactors, such as hydrogen producing rates, substrate turnover rates and metabolites compositions. Therefore, a competition mode of the two dominant bacteria groups was hypothesized. In the study, 16S rRNA-based gene library of hydrogen-producing microbial communities was established. The efficiency of hydrogen yields was correlated with substrates (glucose or sucrose), HRT, metabolites compositions (acetate, propionate, butyrate and ethanol), thermal pre-treatment (seed biomass was heated at 100 degrees C for 45 minutes), and microbial communities in the bioreactor, not sludge sources (municipal sewage sludge, alcohol-processing sludge, or bean-processing sludge). The designed specific oligonucleotide probe Lg10-6 also provides us a useful and fast molecular tool to screen hydrogen-producing microbial communities in the future research.

  20. Forecasting outpatient visits using empirical mode decomposition coupled with back-propagation artificial neural networks optimized by particle swarm optimization.

    Science.gov (United States)

    Huang, Daizheng; Wu, Zhihui

    2017-01-01

    Accurately predicting the trend of outpatient visits by mathematical modeling can help policy makers manage hospitals effectively, reasonably organize schedules for human resources and finances, and appropriately distribute hospital material resources. In this study, a hybrid method based on empirical mode decomposition and back-propagation artificial neural networks optimized by particle swarm optimization is developed to forecast outpatient visits on the basis of monthly numbers. The data outpatient visits are retrieved from January 2005 to December 2013 and first obtained as the original time series. Second, the original time series is decomposed into a finite and often small number of intrinsic mode functions by the empirical mode decomposition technique. Third, a three-layer back-propagation artificial neural network is constructed to forecast each intrinsic mode functions. To improve network performance and avoid falling into a local minimum, particle swarm optimization is employed to optimize the weights and thresholds of back-propagation artificial neural networks. Finally, the superposition of forecasting results of the intrinsic mode functions is regarded as the ultimate forecasting value. Simulation indicates that the proposed method attains a better performance index than the other four methods.

  1. Forecasting outpatient visits using empirical mode decomposition coupled with back-propagation artificial neural networks optimized by particle swarm optimization

    Science.gov (United States)

    Huang, Daizheng; Wu, Zhihui

    2017-01-01

    Accurately predicting the trend of outpatient visits by mathematical modeling can help policy makers manage hospitals effectively, reasonably organize schedules for human resources and finances, and appropriately distribute hospital material resources. In this study, a hybrid method based on empirical mode decomposition and back-propagation artificial neural networks optimized by particle swarm optimization is developed to forecast outpatient visits on the basis of monthly numbers. The data outpatient visits are retrieved from January 2005 to December 2013 and first obtained as the original time series. Second, the original time series is decomposed into a finite and often small number of intrinsic mode functions by the empirical mode decomposition technique. Third, a three-layer back-propagation artificial neural network is constructed to forecast each intrinsic mode functions. To improve network performance and avoid falling into a local minimum, particle swarm optimization is employed to optimize the weights and thresholds of back-propagation artificial neural networks. Finally, the superposition of forecasting results of the intrinsic mode functions is regarded as the ultimate forecasting value. Simulation indicates that the proposed method attains a better performance index than the other four methods. PMID:28222194

  2. Fast-Particle-Driven Alfvenic Modes in a Reversed Field Pinch

    Energy Technology Data Exchange (ETDEWEB)

    Koliner, J. J. [University of Wisconsin, Madison; Forest, C. B. [University of Wisconsin, Madison; Sarff, J. S. [University of Wisconsin, Madison; Anderson, J. [University of Wisconsin, Madison; Liu, D [University of Wisconsin, Madison; Nomberg, M. D. [University of Wisconsin, Madison; Waksman, J. [University of Wisconsin, Madison; Lin, L. [University of California, Los Angeles; Brower, D. L. [University of California, Los Angeles; Ding, W. X. [University of California, Los Angeles; Spong, Donald A [ORNL

    2012-01-01

    Alfvenic modes are observed due to neutral beam injection for the first time in a reversed field pinch plasma. Modeling of the beam deposition and slowing down shows that the velocity and radial localization are high. This allows instability drive from inverse Landau damping of a bump-on-tail in the parallel distribution function or from free energy in the fast ion density gradient. Mode switching from a lower frequency toroidal mode number n = 5 mode that scales with beam injection velocity to a higher frequency n = 4 mode with Alfvenic scaling is observed.

  3. Dynamics of energetic particle driven modes and MHD modes in wall-stabilized high-β plasmas on JT-60U and DIII-D

    Science.gov (United States)

    Matsunaga, G.; Okabayashi, M.; Aiba, N.; Boedo, J. A.; Ferron, J. R.; Hanson, J. M.; Hao, G. Z.; Heidbrink, W. W.; Holcomb, C. T.; In, Y.; Jackson, G. L.; Liu, Y. Q.; Luce, T. C.; McKee, G. R.; Osborne, T. H.; Pace, D. C.; Shinohara, K.; Snyder, P. B.; Solomon, W. M.; Strait, E. J.; Turnbull, A. D.; Van Zeeland, M. A.; Watkins, J. G.; Zeng, L.; the DIII-D Team; the JT-60 Team

    2013-12-01

    In the wall-stabilized high-β plasmas in JT-60U and DIII-D, interactions between energetic particle (EP) driven modes (EPdMs) and edge localized modes (ELMs) have been observed. The interaction between the EPdM and ELM are reproducibly observed. Many EP diagnostics indicate a strong correlation between the distorted waveform of the EPdM and the EP transport to the edge. The waveform distortion is composed of higher harmonics (n ⩾ 2) and looks like a density snake near the plasma edge. According to statistical analyses, ELM triggering by the EPdMs requires a finite level of waveform distortion and pedestal recovery. ELM pacing by the EPdMs occurs when the repetition frequency of the EPdMs is higher than the natural ELM frequency. EPs transported by EPdMs are thought to contribute to change the edge stability.

  4. Excitation of ion Bernstein waves as the dominant parametric decay channel in direct X-B mode conversion for typical spherical torus

    Science.gov (United States)

    Abbasi, Mustafa; Sadeghi, Yahya; Sobhanian, Samad; Asgarian, Mohammad Ali

    2016-03-01

    The electron Bernstein wave (EBW) is typically the only wave in the electron cyclotron (EC) range that can be applied in spherical tokamaks for heating and current drive (H&CD). Spherical tokamaks (STs) operate generally in high- β regimes, in which the usual EC ordinary (O) and extraordinary (X) modes are cut off. As it was recently investigated the existence of EBWs at nonlinear regime thus the next step would be the probable nonlinear phenomena study which are predicted to be occurred within the high levels of injected power. In this regard, parametric instabilities are considered as the major channels for losses at the X-B conversion. Hence, we have to consider their effects at the UHR region which can reduce the X-B conversion efficiency. In the case of EBW heating (EBH) at high power density, the nonlinear effects can arise. Particularly at the UHR position, the group velocity is strongly reduced, which creates a high energy density and subsequently a high amplitude electric field. Therefore, a part of the input wave can decay into daughter waves via parametric instability (PI). Thus, via the present research, the excitations of ion Bernstein waves as the dominant decay channels are investigated and also an estimate for the threshold power in terms of experimental parameters related to the fundamental mode of instability is proposed.

  5. Correlation of Fracture Mode Transition of Ceramic Particle with Critical Velocity for Successful Deposition in Vacuum Kinetic Spraying Process

    Science.gov (United States)

    Park, Hyungkwon; Kim, Jinyoung; Lee, Sung Bo; Lee, Changhee

    2016-12-01

    Vacuum kinetic spraying (VKS) is a promising room-temperature process to fabricate dense ceramic films. However, unfortunately, the deposition mechanism is still not clearly understood. In this respect, the critical conditions for successful deposition were investigated. Based on simulation and microstructural analysis, it was found that as the particle velocity increased, fracture mode transition from tensile fracture to shear fracture occurred and particle did not bounce off anymore above a certain velocity. Simultaneously, particle underwent shock-induced plasticity and dynamic fragmentation. The plasticity assisted to prevent the fragments from rebounding by spending the excessive kinetic energy and fragmentation is essential for fragment bonding and film growth considering that the deposition rate increased as the fraction of fragmentation increased. Accordingly, plasticity and fragmentation take a crucial role for particle deposition. In this respect, the velocity that fracture mode transition occurs is newly defined as critical velocity. Consequently, for successful deposition, the particle should at least exceed the critical velocity and thus it is very crucial for film fabrication in VKS process at room temperature.

  6. Chemometric analysis of multi-sensor hyperspectral images of coarse mode aerosol particles for the image-based investigation on aerosol particles

    Science.gov (United States)

    Ofner, Johannes; Kamilli, Katharina A.; Eitenberger, Elisabeth; Friedbacher, Gernot; Lendl, Bernhard; Held, Andreas; Lohninger, Hans

    2015-04-01

    Multi-sensor hyperspectral imaging is a novel technique, which allows the determination of composition, chemical structure and pure components of laterally resolved samples by chemometric analysis of different hyperspectral datasets. These hyperspectral datasets are obtained by different imaging methods, analysing the same sample spot and superimposing the hyperspectral data to create a single multi-sensor dataset. Within this study, scanning electron microscopy (SEM), Raman and energy-dispersive X-ray spectroscopy (EDX) images were obtained from size-segregated aerosol particles, sampled above Western Australian salt lakes. The particles were collected on aluminum foils inside a 2350 L Teflon chamber using a Sioutas impactor, sampling aerosol particles of sizes between 250 nm and 10 µm. The complex composition of the coarse-mode particles can be linked to primary emissions of inorganic species as well as to oxidized volatile organic carbon (VOC) emissions. The oxidation products of VOC emissions are supposed to form an ultra-fine nucleation mode, which was observed during several field campaigns between 2006 and 2013. The aluminum foils were analysed using chemical imaging and electron microscopy. A Horiba LabRam 800HR Raman microscope was used for vibrational mapping of an area of about 100 µm x 100 µm of the foils at a resolution of about 1 µm. The same area was analysed using a Quanta FEI 200 electron microscope (about 250 nm resolution). In addition to the high-resolution image, the elemental composition could be investigated using energy-dispersive X-ray spectroscopy. The obtained hyperspectral images were combined into a multi-sensor dataset using the software package Imagelab (Epina Software Labs, www.imagelab.at). After pre-processing of the images, the multi-sensor hyperspectral dataset was analysed using several chemometric methods such as principal component analysis (PCA), hierarchical cluster analysis (HCA) and other multivariate methods. Vertex

  7. Linear benchmarks between the hybrid codes HYMAGYC and HMGC to study energetic particle driven Alfvénic modes

    Science.gov (United States)

    Fogaccia, G.; Vlad, G.; Briguglio, S.

    2016-11-01

    Resonant interaction between energetic particles (EPs), produced by fusion reactions and/or additional heating systems, and shear Alfvén modes can destabilize global Alfvénic modes enhancing the EP transport. In order to investigate the EP transport in present and next generation fusion devices, numerical simulations are recognized as a very important tool. Among the various numerical models, the hybrid MHD gyrokinetic one has shown to be a valid compromise between a sufficiently accurate wave-particle interaction description and affordable computational resource requirements. This paper presents a linear benchmark between the hybrid codes HYMAGYC and HMGC. The HYMAGYC code solves the full, linear MHD equations in general curvilinear geometry for the bulk plasma and describes the EP population by the nonlinear gyrokinetic Vlasov equation. On the other side, HMGC solves the nonlinear, reduced O≤ft(ε 03\\right) , pressureless MHD equations ({ε0} being the inverse aspect ratio) for the bulk plasma and the drift kinetic Vlasov equation for the EPs. The results of the HYMAGYC and HMGC codes have been compared both in the MHD limit and in a wide range of the EP parameter space for two test cases (one of which being the so-called TAE n  =  6 ITPA Energetic Particle Group test case), both characterized by {ε0}\\ll 1 . In the first test case (test case A), good qualitative agreement is found w.r.t. real frequencies, growth rates and spatial structures of the most unstable modes, with some quantitative differences for the growth rates. For the so-called ITPA test case (test case B), at the nominal energetic particle density value, the disagreement between the two codes is, on the contrary, also qualitative, as a different mode is found as the most unstable one.

  8. Variational Symplectic Particle-in-cell Simulation of Nonlinear Mode Conversion from Extraordinary waves to Bernstein Waves

    CERN Document Server

    Xiao, Jianyuan; Qin, Hong; Yu, Zhi; Xiang, Nong

    2015-01-01

    In this paper, the nonlinear mode conversion of extraordinary waves in nonuniform magnetized plasmas is studied using the variational symplectic particle-in-cell simulation. The accuracy of the nonlinear simulation is guaranteed by the long-term accuracy and conservativeness of the symplectic algorithm. The spectra of the electromagnetic wave, the evolution of the wave reflectivity, the energy deposition profile, and the parameter-dependent properties of radio-frequency waves during the nonlinear mode conversion are investigated. It is illustrated that nonlinear effects significantly modify the physics of the radio-frequency injection in magnetized plasmas. The evolutions of the radio-frequency wave reflectivity and the energy deposition are observed, as well as the self-interaction of the Bernstein waves and mode excitations. Even for waves with small magnitude, nonlinear effects can also become important after continuous wave injections, which are common in the realistic radio-frequency wave heating and cur...

  9. Time-resolved particle image velocimetry measurements of the 3D single-mode Richtmyer-Meshkov instability

    Science.gov (United States)

    Xu, Qian; Krivets, Vitaliy V.; Sewell, Everest G.; Jacobs, Jeffrey W.

    2016-11-01

    A vertical shock tube is used to perform experiments on the single-mode three-dimensional Richtmyer-Meshkov Instability (RMI). The light gas (Air) and the heavy gas (SF6) enter from the top and the bottom of the shock tube driven section to form the interface. The initial perturbation is then generated by oscillating the gases vertically. Both gases are seeded with particles generated through vaporizing propylene glycol. An incident shock wave (M 1.2) impacts the interface to create an impulsive acceleration. The seeded particles are illuminated by a dual cavity 75W, Nd: YLF laser. Three high-speed CMOS cameras record time sequences of image pairs at a rate of 2 kHz. The initial perturbation used is that of a single, square-mode perturbation with either a single spike or a single bubble positioned at the center of the shock tube. The full time dependent velocity field is obtained allowing the determination of the circulation versus time. In addition, the evolution of time dependent amplitude is also determined. The results are compared with PIV measurements from previous two-dimensional single mode experiments along with PLIF measurements from previous three-dimensional single mode experiments.

  10. Identification of fast particle triggered modes by means of correlation electron cyclotron emission on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Goniche, M.; Huysmans, G.T.A.; Turco, F.; Maget, P.; Segui, J.L.; Artaud, J.F.; Giruzzi, G.; Imbeaux, F.; Lotte, P.; Mazon, D.; Molina, D. [CEA Cadarache, Assoc EURATOM DRFC, SCCP, F-13108 St Paul Les Durance (France); Udintsev, V.S. [EPFL /SB/CRPP, Assoc EURATOM Confederat Suisse, CH-1015 Lausanne (Switzerland)

    2008-07-01

    Low-frequency (5- to 20-kHz) and high-frequency (40- to 200-kHz) modes are studied during radio-frequency heating experiments on the Tore Supra tokamak by means of correlation electron cyclotron emission. High-frequency modes are detected when the plasma is heated by ion cyclotron range of frequency waves in the minority D(H) heating scheme in combination with lower hybrid current drive (LHCD) producing a flat or slightly reversed q-profile. They are identified as Alfven cascade modes. When this mode is triggered, fast ion losses ({<=} 20%) are detected from the neutron emission rate, and an additional heat load on plasma-facing components can be measured by an infrared camera when the fast ion energy is sufficiently large. Low-frequency modes are commonly triggered during LHCD experiments performed at low loop voltage. This mode can be observed with moderate lower hybrid power when the q-profile is monotonic or at higher power when the q-profile is flat in the core (r/a {<=} 0.2) or reversed. It is identified, in most cases, as an electron fishbone-like mode. These modes can be stabilized by a slight modification of the q-profile provided by an increase of lower hybrid power or by a small addition of electron cyclotron current device. (authors)

  11. What is a particle-conserving Topological Superfluid? The fate of Majorana modes beyond mean-field theory

    Science.gov (United States)

    Ortiz, Gerardo; Cobanera, Emilio

    2016-09-01

    We investigate Majorana modes of number-conserving fermionic superfluids from both basic physics principles, and concrete models perspectives. After reviewing a criterion for establishing topological superfluidity in interacting systems, based on many-body fermionic parity switches, we reveal the emergence of zero-energy modes anticommuting with fermionic parity. Those many-body Majorana modes are constructed as coherent superpositions of states with different number of fermions. While realization of Majorana modes beyond mean field is plausible, we show that the challenge to quantum-control them is compounded by particle-conservation, and more realistic protocols will have to balance engineering needs with astringent constraints coming from superselection rules. Majorana modes in number-conserving systems are the result of a peculiar interplay between quantum statistics, fermionic parity, and an unusual form of spontaneous symmetry breaking. We test these ideas on the Richardson-Gaudin-Kitaev chain, a number-conserving model solvable by way of the algebraic Bethe ansatz, and equivalent in mean field to a long-range Kitaev chain.

  12. Energy transmission modes based on Tabu search and particle swarm hybrid optimization algorithm

    Institute of Scientific and Technical Information of China (English)

    LI xiang; CUI Ji-feng; QI Jian-xun; YANG Shang-dong

    2007-01-01

    In China, economic centers are far from energy storage bases, so it is significant to select a proper energy transferring mode to improve the efficiency of energy usage, To solve this problem, an optimal allocation model based on energy transfer mode was proposed after objective function for optimizing energy using efficiency Was established, and then, a new Tabu search and power transmission was gained.Based on the above discussion, some proposals were put forward for optimal allocation of energy transfer modes in China. By comparing other three traditional methodsthat are based on regional price differences. freight rates and annual cost witll the proposed method, the result indicates that the economic efficiency of the energy transfer Can be enhanced by 3.14%, 5.78% and 6.01%, respectively.

  13. Density-gradient-assisted centrifugal microfluidics: an approach to continuous-mode particle separation.

    Science.gov (United States)

    Ukita, Yoshiaki; Oguro, Takayuki; Takamura, Yuzuru

    2017-06-01

    Centrifugal microfluidics has been recognized as a promising pumping method in microfluidics because of its simplicity, easiness of automation, and parallel processing. However, the patterning of stripe flow in centrifugal microfluidics is challenging because a fluid is significantly affected by the Coriolis force, which produces an intrinsic secondary flow. This paper reports a technical and design strategy for centrifugal microfluidics called "density-gradient-assisted centrifugal microfluidics." The flow behavior is observed with the presence of a density gradient and without a density gradient in two concentrically traveling phase flows. As a result, clear stripe flow pattern is observed with a density difference of 0.05 g/cm(3) between water and a percoll solution at a flow rate of 11.8 μl/s (7 ml/10 min) and spinning speed of 3000 rpm. In contrast, without a density gradient, it is necessary to reduce the flow rate and spinning speed to 0.1 μl/s and 1000 rpm, respectively. This paper also presents the use of a density gradient to assist in focusing resin (polystyrene) particles on the boundary of a stripe flow pattern that consists of water and percoll with different densities. Moreover, the density-based separation and sorting of particles in a mixed particle suspension is demonstrated. Polystyrene is selectively focused on the boundary, but silica particles are separated from the focused trajectory due to a difference in density. The separated particles are continuously sorted into different reservoirs with polystyrene and silica separation efficiencies of 96.5% and 98.5%, respectively. The pumping, stripe flow pattern formation, particle concentration, and sorting are simultaneously realized by applying a density gradient and centrifugal force. Therefore, this principle can realize a very simple technique for label-free particle separation by just spinning a disk device and can be applied in other applications by the use of the density

  14. A test beam set-up for the characterization of the Geiger-mode avalanche photodiode technology for particle tracking

    CERN Document Server

    Vilella, A; Trenado, J; Vila, A; Casanova, R; Vos, M; Garrido, L; Dieguez, A

    2012-01-01

    It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite gain and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection still remains unexplored. In this contribution, we are going to expose different steps that we have taken in order to prove the efficiency of the Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present a setup for the characterization of these sensors in a test beam. The expected results of the test beam at DESY and CERN have been simulated with Geant4 and will also be exposed.

  15. Particle-number scaling of the phase sensitivity in realistic Bayesian twin-mode Heisenberg-limited interferometry

    CERN Document Server

    Pooser, R; Pfister, Olivier; Pooser, Raphael

    2003-01-01

    We investigate the scaling of the phase sensitivity of a nonideal Heisenberg-limited interferometer with the particle number N, in the case of the Bayesian detection procedure proposed by Holland and Burnett [p.r.l. 71, p. 1355 (1993)] for twin boson input modes. Using Monte Carlo simulations for up to 10,000 bosons, we show that the phase error of a nonideal interferometer scales with the Heisenberg limit if the losses are of the order of N^-1. Greater losses degrade the scaling which is then in N^-1/2, like the shot-noise limit, yet the sensitivity stays sub-shot-noise as long as photon correlations are present. These results give the actual limits of Bayesian detection for twin-mode interferometry and prove that it is an experimentally feasible scheme, contrary to what is implied by the coincidence-detection analysis of Kim et al. [p.r.a. 60, p. 708 (1999)].

  16. A test beam setup for the characterization of the Geiger-mode avalanche photodiode technology for particle tracking

    Science.gov (United States)

    Vilella, E.; Alonso, O.; Trenado, J.; Vilà, A.; Casanova, R.; Vos, M.; Garrido, L.; Diéguez, A.

    2012-12-01

    It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite gain and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection still remains unexplored. In this contribution, we are going to expose different steps that we have taken in order to prove the efficiency of the Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present a setup for the characterization of these sensors in a test beam. The expected results of the test beam at DESY and CERN have been simulated with Geant4 and will also be exposed.

  17. Nonlinear force dependence on optically bound arrays of micro-particles trapped in the evanescent fields of fundamental and higher order microfibre modes

    CERN Document Server

    Maimaiti, Aili; Truong, Viet Giang; Ritsch, Helmut; Chormaic, Sile Nic

    2016-01-01

    Particles trapped in the evanescent field of an ultrathin optical fibre interact over very long distances via multiple scattering of the fibre-guided fields. In ultrathin fibres that support higher order modes these interactions are stronger and exhibit qualitatively new behaviour due to the coupling of different fibre modes, which have different propagation wave vectors, by the particles. Here, we study one dimensional longitudinal optical binding interactions of chains of 3 {\\mu}m polystyrene spheres under the influence of the evanescent fields of a two-mode microfibre. The observation of long-range interactions, self-ordering and speed variation of particle chains reveals strong optical binding effects between the particles, which can be well modelled by a tritter scattering-matrix approach. The optical forces, optical binding interactions and the velocity of bounded particle chains are calculated using this method. Results show good agreement with finite element numerical simulations. Experimental data an...

  18. Spatiotemporal analysis of turbulent jets enabled by 100-kHz, 100-ms burst-mode particle image velocimetry

    Science.gov (United States)

    Miller, Joseph D.; Jiang, Naibo; Slipchenko, Mikhail N.; Mance, Jason G.; Meyer, Terrence R.; Roy, Sukesh; Gord, James R.

    2016-12-01

    100-kHz particle image velocimetry (PIV) is demonstrated using a double-pulsed, burst-mode laser with a burst duration up to 100 ms. This enables up to 10,000 time-sequential vector fields for capturing a temporal dynamic range spanning over three orders of magnitude in high-speed turbulent flows. Pulse doublets with inter-pulse spacing of 2 µs and repetition rate of 100 kHz are generated using a fiber-based oscillator and amplified through an all-diode-pumped, burst-mode amplifier. A physics-based model of pulse doublet amplification in the burst-mode amplifier is developed and used to accurately predict oscillator pulse width and pulse intensity inputs required to generate equal-energy pulse doublets at 532 nm for velocity measurements. The effect of PIV particle response and high-speed-detector limitations on the spatial and temporal resolution are estimated in subsonic turbulent jets. An effective spatial resolution of 266-275 µm and temporal resolution of 10 µs are estimated from the 8 × 8 pixel correlation window and inter-doublet time spacing, respectively. This spatiotemporal resolution is sufficient for quantitative assessment of integral time and length scales in highly turbulent jets with Reynolds numbers in the range 15,000-50,000. The temporal dynamic range of the burst-mode PIV measurement is 1200, limited by the 85-ms high-energy portion of the burst and 30-kHz high-frequency noise limit.

  19. VUV 157nm laser ablation of spherical particles and modelling of whispering gallery mode optical antenna structures

    Energy Technology Data Exchange (ETDEWEB)

    Walton, C. D.; Cockcroft, S.; Metheringham, W. J. [Department of Physics, University of Hull, HU6 7RX (United Kingdom)

    2012-07-30

    We report on VUV 157nm F{sub 2} laser irradiation of CR-39 polymer substrates that have been intentionally seeded with spherical glass particles. We discuss the importance of adhesive forces for realizing spherical cavity structures by laser ablation. Strong optical absorption at 157nm in CR-39 enables precise control of pedestal height by controlling the laser fluence and the number of laser pulses. Resonant modes for free-standing spherical cavities have been calculated and we discuss briefly the potential applications for use as optical sources on-board lab-on-chip devices.

  20. Full-f Neoclassical Simulations toward a Predictive Model for H-mode Pedestal Ion Energy, Particle and Momentum Transport

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, D. J. [PPPL; Boedo, J. A. [University of California San Diego; Burrell, K. H. [General Atomics; Chang, C. S. [PPPL; Canik, J. M. [ORNL; deGrassie, J. S. [General Atomics; Gerhardt, S. P. [PPPL; Grierson, B. A. [General Atomics; Groebner, R. J. [General Atomics; Maingi, Rajesh [PPPL; Smith, S. P. [General Atomics

    2014-09-01

    Energy and particle transport rates are decoupled in the H-mode edge since the ion thermal transport rate is primarily set by the neoclassical transport of the deuterium ions in the tail of the thermal energy distribution, while the net particle transport rate is set by anomalous transport of the colder bulk ions. Ion orbit loss drives the energy distributions away from Maxwellian, and describes the anisotropy, poloidal asymmetry and local minimum near the separatrix observed in the Ti profile. Non-Maxwellian distributions also drive large intrinsic edge flows, and the interaction of turbulence at the top of the pedestal with the intrinsic edge flow can generate an intrinsic core torque. The primary driver of the radial electric field (Er) in the pedestal and scrapeoff layer (SOL) are kinetic neoclassical effects, such as ion orbit loss of tail ions and parallel electron loss to the divertor. This paper describes the first multi-species kinetic neoclassical transport calculations for ELM-free H-mode pedestal and scrape-off layer on DIII-D using XGC0, a 5D full-f particle-in-cell drift-kinetic solver with self-consistent neutral recycling and sheath potentials. Quantitative agreement between the flux-driven simulation and the experimental electron density, impurity density and orthogonal measurements of impurity temperature and flow profiles is achieved by adding random-walk particle diffusion to the guiding-center drift motion. This interpretative technique quantifies the role of neoclassical, anomalous and neutral transport to the overall pedestal structure, and consequently illustrates the importance of including kinetic effects self-consistently in transport calculations around transport barriers.

  1. Particle-area dependence of mineral dust in the immersion mode: investigations with freely suspended drops in an acoustic levitator

    Directory of Open Access Journals (Sweden)

    K. Diehl

    2014-05-01

    Full Text Available The heterogeneous freezing temperatures of supercooled drops were measured by using an acoustic levitator. This technique allows to freely suspending single drops in air without electrical charges thereby avoiding any electrical influences which may affect the freezing process. Heterogeneous nucleation caused by several mineral dust particles (montmorillonite, two types of illite was investigated in the immersion mode. Drops of 1 \\unit{mm} in radius were monitored by a~video camera during cooling down to −28 °C to simulate the tropospheric temperature range. The surface temperature of the drops was remotely determined with an infra-red thermometer so that the onset of freezing was indicated. For comparisons, measurements with one particle type were additionally performed in the Mainz vertical wind tunnel with drops of 340 \\unit{{\\mu}m} radius freely suspended. The data were interpreted regarding the particle surfaces immersed in the drops. Immersion freezing was observed in a~temperature range between −13 and −26 °C in dependence of particle type and surface area per drop. The results were evaluated by applying two descriptions of heterogeneous freezing, the stochastic and the singular model.

  2. Mode-switching: a new technique for electronically varying the agglomeration position in an acoustic particle manipulator.

    Science.gov (United States)

    Glynne-Jones, Peter; Boltryk, Rosemary J; Harris, Nicholas R; Cranny, Andy W J; Hill, Martyn

    2010-01-01

    Acoustic radiation forces offer a means of manipulating particles within a fluid. Much interest in recent years has focussed on the use of radiation forces in microfluidic (or "lab on a chip") devices. Such devices are well matched to the use of ultrasonic standing waves in which the resonant dimensions of the chamber are smaller than the ultrasonic wavelength in use. However, such devices have typically been limited to moving particles to one or two predetermined planes, whose positions are determined by acoustic pressure nodes/anti-nodes set up in the ultrasonic standing wave. In most cases devices have been designed to move particles to either the centre or (more recently) the side of a flow channel using ultrasonic frequencies that produce a half or quarter wavelength over the channel, respectively. It is demonstrated here that by rapidly switching back and forth between half and quarter wavelength frequencies - mode-switching - a new agglomeration position is established that permits beads to be brought to any arbitrary point between the half and quarter-wave nodes. This new agglomeration position is effectively a position of stable equilibrium. This has many potential applications, particularly in cell sorting and manipulation. It should also enable precise control of agglomeration position to be maintained regardless of manufacturing tolerances, temperature variations, fluid medium characteristics and particle concentration.

  3. Nonlinear force dependence on optically bound micro-particle arrays in the evanescent fields of fundamental and higher order microfibre modes.

    Science.gov (United States)

    Maimaiti, Aili; Holzmann, Daniela; Truong, Viet Giang; Ritsch, Helmut; Nic Chormaic, Síle

    2016-07-25

    Particles trapped in the evanescent field of an ultrathin optical fibre interact over very long distances via multiple scattering of the fibre-guided fields. In ultrathin fibres that support higher order modes, these interactions are stronger and exhibit qualitatively new behaviour due to the coupling of different fibre modes, which have different propagation wave-vectors, by the particles. Here, we study one dimensional longitudinal optical binding interactions of chains of 3 μm polystyrene spheres under the influence of the evanescent fields of a two-mode microfibre. The observation of long-range interactions, self-ordering and speed variation of particle chains reveals strong optical binding effects between the particles that can be modelled well by a tritter scattering-matrix approach. The optical forces, optical binding interactions and the velocity of bounded particle chains are calculated using this method. Results show good agreement with finite element numerical simulations. Experimental data and theoretical analysis show that higher order modes in a microfibre offer a promising method to not only obtain stable, multiple particle trapping or faster particle propulsion speeds, but that they also allow for better control over each individual trapped object in particle ensembles near the microfibre surface.

  4. Nonlinear force dependence on optically bound micro-particle arrays in the evanescent fields of fundamental and higher order microfibre modes

    Science.gov (United States)

    Maimaiti, Aili; Holzmann, Daniela; Truong, Viet Giang; Ritsch, Helmut; Nic Chormaic, Síle

    2016-01-01

    Particles trapped in the evanescent field of an ultrathin optical fibre interact over very long distances via multiple scattering of the fibre-guided fields. In ultrathin fibres that support higher order modes, these interactions are stronger and exhibit qualitatively new behaviour due to the coupling of different fibre modes, which have different propagation wave-vectors, by the particles. Here, we study one dimensional longitudinal optical binding interactions of chains of 3 μm polystyrene spheres under the influence of the evanescent fields of a two-mode microfibre. The observation of long-range interactions, self-ordering and speed variation of particle chains reveals strong optical binding effects between the particles that can be modelled well by a tritter scattering-matrix approach. The optical forces, optical binding interactions and the velocity of bounded particle chains are calculated using this method. Results show good agreement with finite element numerical simulations. Experimental data and theoretical analysis show that higher order modes in a microfibre offer a promising method to not only obtain stable, multiple particle trapping or faster particle propulsion speeds, but that they also allow for better control over each individual trapped object in particle ensembles near the microfibre surface. PMID:27451935

  5. A test beam setup for the characterization of the Geiger-mode avalanche photodiode technology for particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Vilella, E., E-mail: evilella@el.ub.es [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Alonso, O. [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Trenado, J. [Department of Structure and Constituents of Matter, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Vila, A.; Casanova, R. [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Vos, M. [Instituto de Fisica Corpuscular (IFIC), C/Catedratico Jose Beltran 2, 46980 Paterna (Spain); Garrido, L. [Department of Structure and Constituents of Matter, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Dieguez, A. [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain)

    2012-12-01

    It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite gain and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection still remains unexplored. In this contribution, we are going to expose different steps that we have taken in order to prove the efficiency of the Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present a setup for the characterization of these sensors in a test beam. The expected results of the test beam at DESY and CERN have been simulated with Geant4 and will also be exposed. -- Highlights: Black-Right-Pointing-Pointer A Setup for characterization of the GAPD technology in a test beam is presented. Black-Right-Pointing-Pointer Two test beams at DESY (6 GeV) and CERN (120 GeV) are already planned at current time. Black-Right-Pointing-Pointer A GAPD array has been designed and fabricated to fit the test beam requirements. Black-Right-Pointing-Pointer We have prepared a test beam setup to minimize the particle multiscattering. Black-Right-Pointing-Pointer The Expected results at DESY and CERN have been simulated with Geant4.

  6. Mott physics and collective modes: An atomic approximation of the four-particle irreducible functional

    Science.gov (United States)

    Ayral, Thomas; Parcollet, Olivier

    2016-08-01

    We discuss a generalization of the dynamical mean field theory (DMFT) for strongly correlated systems close to a Mott transition based on a systematic approximation of the fully irreducible four-point vertex. It is an atomic-limit approximation of a functional of the one- and two-particle Green functions, built with the second Legendre transform of the free energy with respect to the two-particle Green function. This functional is represented diagrammatically by four-particle irreducible (4PI) diagrams. Like the dynamical vertex approximation (D Γ A ), the fully irreducible vertex is computed from a quantum impurity model whose bath is self-consistently determined by solving the parquet equations. However, in contrast with D Γ A and DMFT, the interaction term of the impurity model is also self-consistently determined. The method interpolates between the parquet approximation at weak coupling and the atomic limit, where it is exact. It is applicable to systems with short-range and long-range interactions.

  7. Resonance broadening due to particle scattering and mode-coupling in the quasi-linear relaxation of electron beams

    CERN Document Server

    Bian, Nicolas H; Ratcliffe, Heather

    2015-01-01

    Of particular interest for radio and hard X-ray diagnostics of accelerated electrons during solar flares is the understanding of the basic non-linear mechanisms regulating the relaxation of electron beams propagating in turbulent plasmas. In this work, it is shown that in addition to scattering of beam electrons, scattering of the beam-generated Langmuir waves via for instance mode-coupling, can also result in broadening of the wave-particle resonance. We obtain a resonance-broadened version of weak-turbulence theory with mode-coupling to ion-sound modes. Resonance broadening is presented here as a unified framework which can quantitatively account for the reduction and possible suppression of the beam instability due to background scattering of the beam electrons themselves or due to scattering of the beam-generated Langmuir waves in fluctuating plasmas. Resonance broadening being essentially equivalent to smoothing of the electron phase-space distribution, it is used to construct an intuitive physical pictu...

  8. Multiobjective Design of Turbo Injection Mode for Axial Flux Motor in Plastic Injection Molding Machine by Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Jian-Long Kuo

    2015-01-01

    Full Text Available This paper proposes a turbo injection mode (TIM for an axial flux motor to apply onto injection molding machine. Since the injection molding machine requires different speed and force parameters setting when finishing a complete injection process. The interleaved winding structure in the motor provides two different injection levels to provide enough injection forces. Two wye-wye windings are designed to switch two control modes conveniently. Wye-wye configuration is used to switch two force levels for the motor. When only one set of wye-winding is energized, field weakening function is achieved. Both of the torque and speed increase under field weakening operation. To achieve two control objectives for torque and speed of the motor, fuzzy based multiple performance characteristics index (MPCI with particle swarm optimization (PSO is used to find out the multiobjective optimal design solution. Both of the torque and speed are expected to be maximal at the same time. Three control factors are selected as studied factors: winding diameter, winding type, and air-gap. Experimental results show that both of the torque and speed increase under the optimal condition. This will provide enough large torque and speed to perform the turbo injection mode in injection process for the injection molding machine.

  9. Dominantly-inherited lop ears.

    Science.gov (United States)

    Leung, Alexander K C; Kong, Albert Y F; Robson, W Lane M; McLeod, D Ross

    2007-10-01

    We describe a four-generation Chinese family that included five members who had an isolated bilateral lop ear anomaly. The presentation suggested a dominant mode of inheritance. The absence of male-to-male transmission does not exclude an X-linked dominant mode of inheritance. Since the phenotypic anomaly of the male proband was no more severe than the affected female members, an autosomal dominant mode of inheritance is most likely. 2007 Wiley-Liss, Inc

  10. Wave-particle interaction and the nonlinear saturation of the electron temperature gradient mode

    Science.gov (United States)

    Vadlamani, Srinath; Parker, Scott E.; Chen, Yang; Howard, James E.

    2004-11-01

    It has been proposed that the electron temperature gradient (ETG) driven turbulence is responsible for experimentally relevant electron thermal transport in tokamak plasmas. Significant transport levels are possible by the creation of radially elongated vortices or ``streamers" [1,2], which are sustained by the nonlinear saturation of the instability and are not susceptible to shear flow destruction, as is the case with the ion temperature gradient (ITG) mode. We present a dynamical system to explore the dependence of saturation level due to E × B and E_\\| motion, as well as the effect of radial elongation. With this model, we can predict the nonlinear saturation level of the ETG streamers. We compare our theoretical predictions with a 2D shear-less slab gyrokinetic electron code that includes the E_\\| nonlinearity. [1]F. Jenko, W. Dorland, M Kotschenreuther, and B.N. Rogers, Phys. Plasmas 7, 1904 (2000). [2]C. Holland, and P.H. Diamond, Phys. Plasmas 9, 3857 (2002). [3]W. M. Manheimer, Phys. Fluids 14, 579 (1971). [4]R. A. Smith, John A. Krommes, and W. W. Lee, Phys. Fluids 28, 1069 (1985).

  11. Modelling of deposited black carbon with the Lagrangian particle dispersion model FLEXPART in backward mode

    Science.gov (United States)

    Eckhardt, Sabine; Cassiani, Massimo; Sollum, Espen; Evangeliou, Nikolaos; Stohl, Andreas

    2017-04-01

    Lagrangian particle dispersion models are popular tools to simulate the dispersion of trace gases, aerosols or radionuclides in the atmosphere. If they consider only linear processes, they are self-adjoint, i.e., they can be run forward and backward in time without changes to the source code. Backward simulations are very efficient if the number of receptors is smaller than the number of sources, and they are well suited to establish source-receptor (s-r) relationships for measurements of various trace substances in air. However, not only the air concentrations are of interest, but also the s-r relationships for deposition are important for interpreting measurement data. E.g., deposition of dust is measured regularly in ice cores, partly also as a proxy to understand changes in aridity in dust source regions. Contamination of snow by black carbon (BC) aerosols has recently become a hot topic because of the potential impact of BC on the snow albedo. To interpret such deposition measurements and study the sources of the deposited substance, it would be convenient to have a model that is capable of efficient s-r relationship calculations for such types of measurements. We present here the implementation of such an algorithm into the Lagrangian particle dispersion model FLEXPART, and test the new scheme by comparisons with results from forward simulations as well as comparisons with measurements. As an application, we analyse source regions for elemental carbon (EC) measured in snow over the years 2014-2016 in the Russian Arctic. Simulations using an annual constant black carbon inventory based on ECLIPSE V5 and GFED (Global Fire Emission Database), have been performed. The meteorological data used in the simulation are 3 hourly operational data from the European Centre of Medium Range Weather Forecast (ECMWF) on a 1 degree grid resolution and 138 vertical levels. The model is able to capture very well the measured concentrations. Gas flaring and residential

  12. Compressible Relativistic Magnetohydrodynamic Turbulence in Magnetically-Dominated Plasmas And Implications for A New Regime

    CERN Document Server

    Takamoto, Makoto

    2016-01-01

    In this Letter, we report compressible mode effects on relativistic magnetohydrodynamic (RMHD) turbulence in Poynting-dominated plasmas using 3-dimensional numerical simulations. We decomposed fluctuations in the turbulence into 3 MHD modes (fast, slow, and Alfv\\'en) following the procedure mode decomposition in (Cho & Lazarian 2002), and analyzed their energy spectra and structure functions separately. We also analyzed the ratio of compressible mode to Alfv\\'en mode energy with respect to its Mach number. We found the ratio of compressible mode increases not only with the Alfv\\'en Mach number but with the background magnetization, which indicates a strong coupling between the fast and Alfv\\'en modes and appearance of a new regime of RMHD turbulence in Poynting-dominated plasmas where the fast and Alfv\\'en modes strongly couples and cannot be distinguished, different from the non-relativistic MHD case. This finding will affect particle acceleration efficiency obtained by assuming Alfv\\'enic critical balan...

  13. The Communication of Culturally Dominant Modes of Attention from Parents to Children: A Comparison of Canadian and Japanese Parent-Child Conversations during a Joint Scene Description Task.

    Science.gov (United States)

    Senzaki, Sawa; Masuda, Takahiko; Takada, Akira; Okada, Hiroyuki

    2016-01-01

    Previous findings have indicated that, when presented with visual information, North American undergraduate students selectively attend to focal objects, whereas East Asian undergraduate students are more sensitive to background information. However, little is known about how these differences are driven by culture and socialization processes. In this study, two experiments investigated how young children and their parents used culturally unique modes of attention (selective vs. context sensitive attention). We expected that children would slowly learn culturally unique modes of attention, and the experience of communicating with their parents would aid the development of such modes of attention. Study 1 tested children's solitary performance by examining Canadian and Japanese children's (4-6 vs. 7-9 years old) modes of attention during a scene description task, whereby children watched short animations by themselves and then described their observations. The results confirmed that children did not demonstrate significant cross-cultural differences in attention during the scene description task while working independently, although results did show rudimentary signs of culturally unique modes of attention in this task scenario by age 9. Study 2 examined parent-child (4-6 and 7-9 years old) dyads using the same task. The results indicated that parents communicated to their children differently across cultures, replicating attentional differences among undergraduate students in previous cross-cultural studies. Study 2 also demonstrated that children's culturally unique description styles increased significantly with age. The descriptions made by the older group (7-9 years old) showed significant cross-cultural variances in attention, while descriptions among the younger group (4-6 years old) did not. The significance of parental roles in the development of culturally unique modes of attention is discussed in addition to other possible facilitators of this

  14. Target particle and heat loads in low-triangularity L-mode plasmas in JET with carbon and beryllium/tungsten walls

    NARCIS (Netherlands)

    Groth, M.; Brezinsek, S.; Belo, P.; Corrigan, G.; Harting, D.; Wiesen, S.; Beurskens, M. N. A.; Brix, M.; Clever, M.; Coenen, J. W.; Eich, T.; Flanagan, J.; Giroud, C.; Huber, A.; Jachmich, S.; Kruezi, U.; Lehnen, M.; Lowry, C.; Maggi, C. F.; Marsen, S.; Meigs, A. G.; Sergienko, G.; Sieglin, B.; Silva, C.; Sirinelli, A.; Stamp, M. F.; van Rooij, G. J.

    2013-01-01

    Divertor radiation profiles, and power and particle fluxes to the target have been measured in attached \\{JET\\} L-mode plasmas with carbon and beryllium/tungsten wall materials. In the beryllium/tungsten configuration, factors of 2–3 higher power loads and peak temperatures at the low field side tar

  15. Two- and three-particle states in a nonrelativistic four-fermion model in the fine-tuning renormalization scheme: Goldstone mode versus extension theory

    CERN Document Server

    Vall, A N; Leviant, V M; Naumov, D V; Sinitskaya, A V

    2001-01-01

    In a nonrelativistic contact four-fermion model we show that simple regularization prescriptions together with a definite fine-tuning of the cut-off parameter dependence of 'bare' quantities give the exact solutions for the two-particle sector and Goldstone modes. Their correspondence with the self-adjoint extension into Pontryagin space is established leading to self-adjoint semi-bounded Hamiltonians in three-particle sectors as well. Renormalized Faddeev equations for the bound states with Fredholm properties are obtained and analyzed. (author)

  16. Effects of particle shape, hematite content and semi-external mixing with carbonaceous components on the optical properties of accumulation mode mineral dust

    Directory of Open Access Journals (Sweden)

    S. K. Mishra

    2010-12-01

    Full Text Available The radiative forcing estimation of the polluted mineral dust is limited due to lack of morphological analysis, mixing state with the carbonaceous components and the hematite content in the pure dust. The accumulation mode mineral dust has been found to mix with anthropogenically produced black carbon, organic carbon and brown carbon during long range transport. The above features of the polluted dust are not well accounted in the optical models and lead the uncertainty in the numerical estimation of their radiative impact. The Semi-external mixing being a prominent mixing of dust and carbonaceous components has not been studied in details so for compared to core-shell, internal and external mixing studies. In present study, we consider the pure mineral dust composed of non-metallic components (such as Quartz, Feldspar, Mica and Calcite and metalic component like hematite (Fe2O3. The hematite percentage in the pure mineral dust governs its absorbance. Based on this hematite variation, the hematite fraction in pure mineral dust has been constrained between 0–8%. The morphological and mineralogical characterization of the polluted dust led to consider the three sphere, two sphere and two spheroid model shapes for polluted dust particle system. The pollution gives rise to various light absorbing aerosol components like black carbon, brown carbon and organic carbon (comprising of HUmic-Like Substances, HULIS in the atmosphere. The entire above discussed model shapes have been considered for the mineral dust getting polluted with (1 organic carbon (especially HULIS component (2 Brown carbon and (3 black carbon by making a semi-external mixture with pure mineral dust. The optical properties (like Single Scattering Albedo, SSA; Asymmetry parameter, g and Extinction efficiency, Qext of above model shapes for the polluted dust have been computed using Discrete Dipole Approximation, DDA code. For above

  17. Particules metadiscursives et autres modes langagieres: des cas de changement linguistique (Metadiscursive Particles and Other Language Modes: Cases of Linguistic Change).

    Science.gov (United States)

    Vincent, Diane; Martel, Guylaine

    2001-01-01

    This article focuses on the use of metadiscursive expressions and discourse particles that are produced in great numbers by two groups of Montreal French speakers in different time periods and that have generally been regarded as language ticks. Elements of the first group make explicit the conscious state of speakers with respect to their…

  18. Self-consistent long-time simulation of chirping energetic particle modes and abrupt large events in beam-driven JT-60U tokamak plasmas

    Science.gov (United States)

    Bierwage, A.; Shinohara, K.; Todo, Y.; Aiba, N.; Ishikawa, M.; Matsunaga, G.; Takechi, M.; Yagi, M.

    2016-10-01

    Recurring bursts of chirping Alfvén modes as well as so-called Abrupt Large Events (ALE) that were observed in JT-60U tokamak plasmas driven by negative-ion-based neutral beams (N-NB) are reproduced in first-principle simulations performed with an extended version of the hybrid code MEGA. This code simulates the interactions between gyrokinetic fast ions and magnetohydrodynamic (MHD) modes in the presence of a realistic fast ion source and collisions, so that it self-consistently captures dynamics across a wide range of time scales (0.01-100 ms). Detailed comparisons with experimental measurements are performed. On the long time scale (10-100 ms) the simulation reproduces ALEs with the associated avalanche-like transport of fast ions. ALEs are shown to occur when multiple modes with toroidal mode numbers n = 1 , 2 , 3 are excited to large amplitudes. On the meso time scale (1-10 ms), bursts of chirping modes are reproduced, which are shown to be n = 1 energetic particle modes (EPM). On the short time scale (0.01-0.1 ms), pulsations and phase jumps are reproduced, which we interpret as the result of beating between multiple resonant wave packets. JSPS Grant-in-Aid for Scientific Research (No. 25820443, 16K18341). NIFS Collaborative Research Program (NIFS12KNTT016).

  19. Single-particle and collective mode couplings associated with 1- and 2-directional electronic ordering in metallic RTe3 (R=Ho,Dy,Tb).

    Science.gov (United States)

    Yusupov, R V; Mertelj, T; Chu, J-H; Fisher, I R; Mihailovic, D

    2008-12-12

    The coupling of phonons with collective modes and single-particle gap excitations associated with one- (1d) and two-directional (2d) electronically driven charge-density wave (CDW) ordering in metallic RTe3 is investigated as a function of rare-earth ion chemical pressure (R=Tb,Dy,Ho) using femtosecond pump-probe spectroscopy. From the T dependence of the CDW gap DeltaCDW and the amplitude mode, we find that while the transition to a 1d-CDW ordered state at Tc1 initially proceeds in an exemplary mean-field-like fashion, below Tc1, DeltaCDW is depressed and departs from the mean-field behavior. The effect is apparently triggered by resonant mode mixing of the amplitude mode with a totally symmetric phonon at 1.75 THz. At low temperatures, when the state evolves into a 2d-CDW ordered state at Tc2 in the DyTe3 and HoTe3, additional much weaker mode mixing is evident but no soft mode is observed.

  20. Dominant viral pathologies in the extensive and semi-intensive animal breeding and their treatment mode in ethno veterinary medicine in Benin

    Directory of Open Access Journals (Sweden)

    T. M. Kpodékon

    2015-12-01

    Full Text Available Aim: This study aims to identify the dominant viral animal pathologies and to list the traditional recipes used by the breeders for their treatment. Materials and Methods: The method of data collection was based on a retrospective survey. Thus, 787 breeders and agro-breeders scattered in the eight agro-ecological areas of Benin were interviewed using semi-structured questionnaires. Results: In total, 5 pathologies were reported by breeders. Among those pathologies, foot and mouth disease was reported by all of the breeders of the southern part of Borgou compared with the other areas (p<0.05 and treated by 25 species of medicinal plants. African swine fever was the main pathology reported (22.92% (p<0.05 in the fishery areas which is controlled by 7 medicinal plants. Pseudorinderpest was more reported (33.78% (p<0.05 in the cotton area of central Benin and treated by 8 medicinal plants. There is also Newcastle disease that was mostly reported in the Western Atacora and treated by 32 medicinal plants as well as fowl pox which was a more reported in the lands of the bar area and the low-pressure area about 34.48% and 36.17% proportions, respectively, and treated by eight medicinal plants. Conclusion: The breeders in Benin possess rich ethno veterinary knowledge on medicinal plants and their uses in the treatment of livestock. A total of 57 medicinal plants have been inventoried to fight against five major viral diseases as African swine fever, pseudorinderpest and foot and mouth disease. The common plants used to treat viral disease in general were Euphorbia unispina, Euphorbia poissonii, Lannea acida, and Mangifera indica. The most harvested organs on the plants reported in this survey were the barks, the leaves, and the whole plants. To better develop our indigenous resources, it would be important to expand this ethno-pharmacological investigation to other diseases category.

  1. Verification of gyrokinetic particle simulation of current-driven instability in fusion plasmas. III. Collisionless tearing mode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dongjian [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Southwestern Institution of Physics, Chengdu 610041 (China); Bao, Jian [Fusion Simulation Center, Peking University, Beijing 100871 (China); Han, Tao; Wang, Jiaqi [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Lin, Zhihong, E-mail: zhihongl@uci.edu [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)

    2016-02-15

    A finite-mass electron fluid model for low frequency electromagnetic fluctuations, particularly the collisionless tearing mode, has been implemented in the gyrokinetic toroidal code. Using this fluid model, linear properties of the collisionless tearing mode have been verified. Simulations verify that the linear growth rate of the single collisionless tearing mode is proportional to D{sub e}{sup 2}, where D{sub e} is the electron skin depth. On the other hand, the growth rate of a double tearing mode is proportional to D{sub e} in the parameter regime of fusion plasmas.

  2. Access conditions, energy and particle confinement of the I-mode regime on Alcator C-Mod

    Science.gov (United States)

    Hubbard, Amanda

    2015-11-01

    Experiments on C-Mod have shown an extended operating range for I-mode at higher magnetic fields, offering options for high-performance, ELM-suppressed operation in future devices. Stationary regimes without significant ELMs are a requirement for ITER and other large burning devices. The I-mode regime offers one potential solution. It features a strong Te and Ti pedestal, up to 1 keV, without a density pedestal. I-mode has been demonstrated on the C-Mod, ASDEX Upgrade and DIII-D tokamaks, over increasingly wide parameter ranges. On C-Mod, global energy confinement is comparable to H-mode, with H98 between 0.7 and 1.2. Scaling of τE with Pheat-0 . 3 is more favorable than H-mode. This lack of saturation and the natural stability to ELMs can now be understood in terms of pedestal stability, with pressure and current gradients well away from stability limits. Impurity confinement τimp is similar in level and scaling to that in L-mode, 15-30 ms for both Ca and Mo, vs 0.1-1 s in H-mode. Key questions for extrapolation to other devices are the conditions for L-I transitions and for avoiding transitions to H-mode. An important new result is that the L-I threshold is independent of field, while the upper range of power for I-mode increases with BT leading to a wider operating space; at 5 T and above, many discharges remain in stationary I-mode with the full heating power of 5 MW. Scaling thresholds with size suggests that I-mode should be obtainable on ITER. Some I-modes have been observed up to 8 T. Another key question for any regime is compatibility with boundary solutions. In usual operation with Bxgrad drift away from the X-point, heat flux is predominantly to the inner divertor leg. Impurity seeding is used to reduce the flux, taking advantage of low τimp. I-modes have now been extended to near-balanced double null. Supported by DOE Award DEFC02- 99ER54512-CMOD.

  3. Verification of gyrokinetic particle simulation of current-driven instability in fusion plasmas. I. Internal kink mode

    Energy Technology Data Exchange (ETDEWEB)

    McClenaghan, J.; Lin, Z.; Holod, I.; Deng, W.; Wang, Z. [University of California, Irvine, California 92697 (United States)

    2014-12-15

    The gyrokinetic toroidal code (GTC) capability has been extended for simulating internal kink instability with kinetic effects in toroidal geometry. The global simulation domain covers the magnetic axis, which is necessary for simulating current-driven instabilities. GTC simulation in the fluid limit of the kink modes in cylindrical geometry is verified by benchmarking with a magnetohydrodynamic eigenvalue code. Gyrokinetic simulations of the kink modes in the toroidal geometry find that ion kinetic effects significantly reduce the growth rate even when the banana orbit width is much smaller than the radial width of the perturbed current layer at the mode rational surface.

  4. Additivity dominance

    Directory of Open Access Journals (Sweden)

    Paul Rozin

    2009-10-01

    Full Text Available Judgments of naturalness of foods tend to be more influenced by the process history of a food, rather than its actual constituents. Two types of processing of a ``natural'' food are to add something or to remove something. We report in this study, based on a large random sample of individuals from six countries (France, Germany, Italy, Switzerland, UK and USA that additives are considered defining features of what makes a food not natural, whereas ``subtractives'' are almost never mentioned. In support of this, skim milk (with major subtraction of fat is rated as more natural than whole milk with a small amount of natural vitamin D added. It is also noted that ``additives'' is a common word, with a synonym reported by a native speaker in 17 of 18 languages, whereas ``subtractive'' is lexicalized in only 1 of the 18 languages. We consider reasons for additivity dominance, relating it to omission bias, feature positive bias, and notions of purity.

  5. Interweaving of elementary modes of excitation in superfluid nuclei through particle-vibration coupling: Quantitative account of the variety of nuclear structure observables

    Science.gov (United States)

    Idini, A.; Potel, G.; Barranco, F.; Vigezzi, E.; Broglia, R. A.

    2015-09-01

    A complete characterization of the structure of nuclei can be obtained by combining information arising from inelastic scattering, Coulomb excitation, and γ -decay, together with one- and two-particle transfer reactions. In this way it is possible to probe both the single-particle and collective components of the nuclear many-body wave function resulting from the coupling of these modes and, as a result, diagonalizing the low-energy Hamiltonian. We address the question of how accurately such a description can account for experimental observations in the case of superfluid nuclei. Our treatment goes beyond the traditional approach, in which these properties are calculated separately, and most often for systems near closed shells, based on perturbative approximations (weak coupling). It is concluded that renormalizing empirically and on equal footing bare single-particle and collective motion of open-shell nuclei in terms of self-energy (mass) and vertex corrections (screening), as well as particle-hole and pairing interactions through particle-vibration coupling (PVC), leads to a detailed, quantitative account of the data, constraining the possible values of the k mass, of the 1S0 bare N N interaction, and of the PVC strengths within a rather narrow window.

  6. ITER Plasma at Ion Cyclotron Frequency Domain: The Fusion Alpha Particles Diagnostics Based on the Stimulated Raman Scattering of Fast Magnetosonic Wave off High Harmonic Ion Bernstein Modes

    Science.gov (United States)

    Stefan, V. Alexander

    2014-10-01

    A novel method for alpha particle diagnostics is proposed. The theory of stimulated Raman scattering, SRS, of the fast wave and ion Bernstein mode, IBM, turbulence in multi-ion species plasmas, (Stefan University Press, La Jolla, CA, 2008). is utilized for the diagnostics of fast ions, (4)He (+2), in ITER plasmas. Nonlinear Landau damping of the IBM on fast ions near the plasma edge leads to the space-time changes in the turbulence level, (inverse alpha particle channeling). The space-time monitoring of the IBM turbulence via the SRS techniques may prove efficient for the real time study of the fast ion velocity distribution function, spatial distribution, and transport. Supported by Nikola Tesla Labs., La Jolla, CA 92037.

  7. Simulations of flow mode distributions on rough fracture surfaces using a parallelized Smoothed Particle Hydrodynamics (SPH) model

    Science.gov (United States)

    Kordilla, J.; Shigorina, E.; Tartakovsky, A. M.; Pan, W.; Geyer, T.

    2015-12-01

    Under idealized conditions (smooth surfaces, linear relationship between Bond number and Capillary number of droplets) steady-state flow modes on fracture surfaces have been shown to develop from sliding droplets to rivulets and finally (wavy) film flow, depending on the specified flux. In a recent study we demonstrated the effect of surface roughness on droplet flow in unsaturated wide aperture fractures, however, its effect on other prevailing flow modes is still an open question. The objective of this work is to investigate the formation of complex flow modes on fracture surfaces employing an efficient three-dimensional parallelized SPH model. The model is able to simulate highly intermittent, gravity-driven free-surface flows under dynamic wetting conditions. The effect of surface tension is included via efficient pairwise interaction forces. We validate the model using various analytical and semi-analytical relationships for droplet and complex flow dynamics. To investigate the effect of surface roughness on flow dynamics we construct surfaces with a self-affine fractal geometry and roughness characterized by the Hurst exponent. We demonstrate the effect of surface roughness (on macroscopic scales this can be understood as a tortuosity) on the steady-state distribution of flow modes. Furthermore we show the influence of a wide range of natural wetting conditions (defined by static contact angles) on the final distribution of surface coverage, which is of high importance for matrix-fracture interaction processes.

  8. Reconciliation of coarse mode sea-salt aerosol particle size measurements and parameterizations at a subtropical ocean receptor site

    NARCIS (Netherlands)

    Reid, J.S.; Brooks, B.; Crahan, K.K.; Leeuw, G. de; Reid, E.A.; Anderson, F.D.; Hegg, D.A.; Eck, T.F.; O'Neill, N.

    2006-01-01

    In August/September of 2001, the R/P FLIP and CIRPAS Twin Otter research aircraft were deployed to the eastern coast of Oahu, Hawaii, as part of the Rough Evaporation Duct (RED) experiment. Goals included the study of the air/sea exchange, turbulence, and sea-salt aerosol particle characteristics at

  9. Final Technical Report on STTR Project DE-FG02-06ER86281 Particle Tracking in Matter-Dominated Beam Lines (G4beamline)

    Energy Technology Data Exchange (ETDEWEB)

    Muons, Inc.

    2011-05-19

    This project has been for software development of the G4beamline [1] program, which is a particle-tracking simulation program based on the Geant4 toolkit [2], optimized for beam lines. This program can perform more realistic simulations than most alternatives, while being significantly easier to use by physicists. This project has fostered the general acceptance of G4beamline within the muon community, and has assisted in expanding its role outside that community. During this project, the G4beamline user community has grown from about a half-dozen users to more than 200 users around the world. This project also validated our business decision to keep G4beamline an open-source program, judging that an STTR project would provide more development resources than would marketing and selling the program. G4beamline is freely available to the physics community, and has been well validated against experiments and other codes within its domain. Muons, Inc. continues to support and develop the program, and a major part of the company's continued success and growth is directly related to our expertise in applying this program to interesting applications.

  10. The influence of toroidal Alfvén modes on the confinement of fast particles in the Globus-M spherical tokamak

    Science.gov (United States)

    Petrov, Yu. V.; Bakharev, N. N.; Gusev, V. K.; Minaev, V. B.; Kornev, V. A.; Mel'nik, A. D.; Patrov, M. I.; Sakharov, N. V.; Tolstyakov, S. Yu.; Kurskiev, G. S.; Chernyshev, F. V.; Shchegolev, P. B.

    2014-12-01

    Neutral beam injection into the Globus-M spherical tokamak at the early stage of discharge leads to the development of instabilities in a frequency range of 50-200 kHz, which have been identified as toroidal Alfvén eigenmodes (TAEs) [1]. The influence of these modes on the confinement of fast particles has been studied with the aid of a neutral particle analyzer (NPA) and a neutron detector. The isotope effect was studied using hydrogen and deuterium both in the injected beam and in the target plasma. A correlation analysis of signals from magnetic probes showed that the observed modes in most cases contain a single harmonic with toroidal number n = 1. Upon the injection of deuterium into deuterium plasma, the development of TAEs led to a decrease in the neutron flux by 25%, whereas the fluxes of high-energy recharge atoms decreased by 75%. After the injection of hydrogen, a decrease in the flux measured by NPA did not exceed 25%.

  11. A particle-in-cell mode beam dynamics simulation of medium energy beam transport for the SSC-Linac

    Science.gov (United States)

    Xiao, Chen; He, Yuan; Yuan, You-Jin; Lu, Yuan-Rong; Liu, Yong; Wang, Zhi-Jun; Du, Xiao-Nan; Yao, Qing-Gao; Liu, Ge; Xu, Meng-Xin; He, Shou-Bo; Xia, Jia-Wen

    2012-01-01

    A new linear accelerator system, called the SSC-Linac injector, is being designed at HIRFL (the heavy ion research facility of Lanzhou). As part of the SSC-Linac, the medium energy beam transport (MEBT) consists of seven magnetic quadrupoles, a re-buncher and a diagnose box. The total length of this segment is about 1.75 m. The beam dynamics simulation in MEBT has been studied using the TRACK 3D particle-in-cell code, and the simulation result shows that the beam accelerated from the radio frequency quadrupole (RFQ) matches well with the acceptance of the following drift tube linac (DTL) in both the transverse and longitudinal phase spaces, and that most of the particles can be captured by the final sector focusing cyclotron for further acceleration. The longitudinal emittance of the RFQ and the longitudinal acceptance of the DTL was calculated in detail, and a multi-particle beam dynamics simulation from the ion source to the end of the DTL was done to verify the original design.

  12. Discrimination of domination mode and chaotic mode in species

    OpenAIRE

    Adachi, Shun

    2016-01-01

    The concepts of a population and a species play fundamental roles in biology. The existence and precise definition of higher-order hierarchies, such as division into species, is open to debate among biologists. Here we show a new metric, `small $s$', that distinguishes the population number and various data values that are beyond the range of neutral logarithmic populations and are specific to a given species with quantization, by the data from natural environments. We modify Price equation t...

  13. Domination, Eternal Domination, and Clique Covering

    Directory of Open Access Journals (Sweden)

    Klostermeyer William F.

    2015-05-01

    Full Text Available Eternal and m-eternal domination are concerned with using mobile guards to protect a graph against infinite sequences of attacks at vertices. Eternal domination allows one guard to move per attack, whereas more than one guard may move per attack in the m-eternal domination model. Inequality chains consisting of the domination, eternal domination, m-eternal domination, independence, and clique covering numbers of graph are explored in this paper.

  14. A particle-in-cell mode beam dynamics simulation of medium energy beam transport for the SSC-Linac

    Institute of Scientific and Technical Information of China (English)

    XIAO Chen; XU Meng-Xin; HE Shou-Bo; XIA Jia-Wen; HE Yuan; YUAN You-Jin; LU Yuan-Rong; LIU Yong; WANG Zhi-Jun; DU Xiao-Nan; YAO Qing-Gao; LIU Ge

    2012-01-01

    A new linear accelerator system,called the SSC-Linac injector,is being designed at HIRFL (the heavy ion research facility of Lanzhou).As part of the SSC-Linac,the medium energy beam transport (MEBT) consists of seven magnetic quadrupoles,a re-buncher and a diagnose box.The total length of this segment is about 1.75 m.The beam dynamics simulation in MEBT has been studied using the TRACK 3D particlein-cell code,and the simulation result shows that the beam accelerated from the radio frequency quadrupole (RFQ) matches well with the acceptance of the following drift tube linac (DTL) in both the transverse and longitudinal phase spaces,and that most of the particles can be captured by the final sector focusing cyclotronfor further acceleration.The longitudinal emittance of the RFQ and the longitudinal acceptance of the DTL was calculated in detail,and a multi-particle beam dynamics simulation from the ion source to the end of the DTL was done to verify the original design.

  15. 主导模式对供应链决策、稳定性和效率的影响分析%Analysis of Supply Chain Decision, Stability and Efficiency Based on Dominant Mode

    Institute of Scientific and Technical Information of China (English)

    公彦德; 李帮义

    2012-01-01

    企业与企业之间的竞争模式已被供应链与供应链之间的竞争模式所取代,而目前供应链模型的研究主要是针对某一特定供应链.基于此,依据制造商主导和第三方物流服务商主导的两类供应链模式,在物流费用由制造商和零售商共同承担的条件下,运用博弈论分析了非合作决策下两类供应链模式的定价和企业利润,得出TPLSP主导的供应链系统效率大于制造商主导的供应链系统效率.在不同的主导模式下,给出了两类供应链模式下制造商和零售商的外包策略,分析了零售商与外包型的制造商或自营型的制造商进行合作时的系统稳定性.最后通过比较合作决策和非合作决策下的利润及价格,给出了合作决策下的一种基于机会成本的供应链协调方法.%Although the competition mode between enterprises and enterprise has been replaced by the competition mode between supply chain and supply chain, supply chain model is still examined from the perspective of single supply chain. In recognition of the literature gap, this paper proposes inter-enterprise competition be studied from two supply chain modes: { 1 ) logistics cost is shared by manufacturer and retailer, and (2) pricing and supply chain profits are calculated with the game theory in a non-cooperative decision-making manner. . First, this paper proposes optimal forward logistics strategy and optimal reverse logistics strategy in these two dominant modes for a manufacturer. In the manufacturer-leading mode, if k2 > S / (1-S2) the optimal forward logistics strategy for a manufacturer is logistics outsourcing. On the contrary, the optimal forward logistics strategy for a manufacturer is self-support logistics. If l2 > T2/ (1 - 72), the optimal reverse logistics strategy for a manufacturer is logistics outsourcing. On the contrary, the optimal reverse logistics strategy for manufacturer is self-support logistics. In the TPLSP-leading mode

  16. Particle-in-cell mode beam dynamics simulation of the low energy beam transport for the SSC-linac injector

    Institute of Scientific and Technical Information of China (English)

    XIAO Chen; HE Yuan; YUAN You-Jin; YAO Qing-Gao; WANG Zhi-Jun; CHANG Wei; LIU Yong; XIA Jia-Wen

    2011-01-01

    A new SSC-linac system (injector into separated sector cyclotron) is being designed in the HIRFL (heavy ion research facility of Lanzhou). As part of SSC-Linac, the LEBT (low energy beam transport) consists of seven solenoids, four quadrupoles, a bending magnet and an extra multi-harmonic buncher. The total length of this segment is about 7 meters. The beam dynamics in this LEBT has been studied using three-dimensional PIC (particle-in-cell) code BEAMPATH. The simulation results show that the continuous beam from the ion source is first well analyzed by a charge-to-mass selection system, and the beam of the selected charge-to-mass ratio is then efficiently pre-bunched by a multi-harmonic buncher and optimally matched into the RFQ (radio frequency quadrupole) for further acceleration. The principles and effects of the solenoid collimation channel are discussed, and it could limit the beam emittance by changing the aperture size.

  17. Design and Study on Sliding Mode Extremum Seeking Control of the Chaos Embedded Particle Swarm Optimization for Maximum Power Point Tracking in Wind Power Systems

    Directory of Open Access Journals (Sweden)

    Jui-Ho Chen

    2014-03-01

    Full Text Available This paper proposes a sliding mode extremum seeking control (SMESC of chaos embedded particle swarm optimization (CEPSO Algorithm, applied to the design of maximum power point tracking in wind power systems. Its features are that the control parameters in SMESC are optimized by CEPSO, making it unnecessary to change the output power of different wind turbines, the designed in-repetition rate is reduced, and the system control efficiency is increased. The wind power system control is designed by simulation, in comparison with the traditional wind power control method, and the simulated dynamic response obtained by the SMESC algorithm proposed in this paper is better than the traditional hill-climbing search (HCS and extremum seeking control (ESC algorithms in the transient or steady states, validating the advantages and practicability of the method proposed in this paper.

  18. Dynamics of the electric current in an ideal electron gas: a sound mode inside the quasi-particles

    CERN Document Server

    Grozdanov, Sašo

    2015-01-01

    We study the equation of motion for the Noether current in an electron gas within the framework of the Schwinger-Keldysh Closed-Time-Path formalism. The equation is shown to be highly non-linear and irreversible even for a non-interacting, ideal gas of electrons at non-zero density. We truncate the linearised equation of motion, written as the Laurent series in Fourier space, so that the resulting expressions are local in time, both at zero and at small finite temperatures. Furthermore, we show that the one-loop Coulomb interactions only alter the physical picture quantitatively, while preserving the characteristics of the dynamics that the electric current exhibits in the absence of interactions. As a result of the composite nature of the Noether current, composite sound waves are found to be the dominant IR collective excitations at length scales between the inverse Fermi momentum and the mean free path that would exist in an interacting electron gas. We also discuss the difference and the transition betwee...

  19. Alfven mode stability and wave-particle interaction in the JET tokamak: prospects for scenario development and control schemes in burning plasma experiments

    Energy Technology Data Exchange (ETDEWEB)

    Testa, D [CRPP, Association EURATOM-Confederation Suisse, EPFL, Lausanne (Switzerland); Fasoli, A [CRPP, Association EURATOM-Confederation Suisse, EPFL, Lausanne (Switzerland); Borba, D [Associacao EURATOM/IST (Portugal); EDFA-CSU, Culham Science Centre (United Kingdom); Baar, M de [FOM-Instituut Voor Plasmafysica, Rijnhuizen (Netherlands); Bigi, M [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Brzozowski, J [NADA VR-Euratom Association, Royal Institute of Technology, Stockholm (Sweden); Vries, P de [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon (United Kingdom)

    2004-07-01

    We have investigated the effect of different ion cyclotron resonance frequency (ICRF) heating schemes, of error field modes, of the plasma shape and edge magnetic shear, and of the ion {nabla}B drift direction on the stability of Alfven eigenmodes (AEs). The use of multi-frequency or 2nd harmonic minority ICRF heating at high plasma density gives rise to a lower fast ion pressure gradient in the plasma core and to a reduced mode activity in the Alfven frequency range. Externally excited low-amplitude error fields lead to a much larger AE instability threshold, which we attribute to a moderate radial redistribution of the fast ions. The edge plasma shape has a clear stabilizing effect on high-n, radially localized AEs. The damping rate of n = 1 toroidal AEs is a factor 3 higher when the ion {nabla}B drift is directed towards the divertor. These results represent a useful step towards the extrapolation of current scenarios to the inclusion of fusion-born alpha particles in ITER, with possible application for feedback control schemes for the various ITER operating regimes.

  20. Separation of Silver Nanoparticles with Different Coatings by Capillary Electrophoresis Coupled to ICP-MS in Single Particle Mode.

    Science.gov (United States)

    Mozhayeva, Darya; Engelhard, Carsten

    2017-09-19

    The possibility of separating mixtures of Ag nanoparticles (NPs) with similar sizes but different surface coatings using capillary electrophoresis coupled to single particle inductively coupled mass-spectrometry (CE-SP-ICP-MS) was investigated. In two-component mixtures, it was possible to separate 40 nm sized polyvinylpirrolidone (PVP)- and citrate-coated NPs, 40 nm sized polyethylene glycol (PEG)- and citrate-coated NPs, and 60 nm sized PVP- and citrate-coated NPs. The separation of a more complex mixture containing NPs with the different coatings and sizes was successful, and each component, namely, 20, 40, and 60 nm sized citrate-coated and 40 and 60 nm sized PVP-coated NPs, could be distinguished. The theoretically expected migration order was confirmed by experimental results with selected Ag NPs. On the basis of the experimental observations, a separation mechanism that considers the effect of stable vs displaceable coatings during NP migration in CE is suggested. The ICP-MS was equipped with a prototype data acquisition system (μsDAQ) that provided 5 μs time resolution.

  1. Helicity-based particle-relabeling operator and normal mode expansion of the dissipationless incompressible Hall magnetohydrodynamics.

    Science.gov (United States)

    Araki, Keisuke

    2015-12-01

    The dynamics of an incompressible, dissipationless Hall magnetohydrodynamic medium are investigated from Lagrangian mechanical viewpoint. The hybrid and magnetic helicities are shown to emerge, respectively, from the application of the particle relabeling symmetry for ion and electron flows to Noether's first theorem, while the constant of motion associated with the theorem is generally given by their arbitrary linear combination. Furthermore, integral path variation associated with the invariant action is expressed by the operation of an integrodifferential operator on the reference path. The eigenfunctions of this operator are double Beltrami flows, i.e., force-free stationary solutions to the equation of motion and provide a family of orthogonal function bases that yields the spectral representation of the equation of motion with a remarkably simple form. Among the double Beltrami flows, considering the influence of a uniform background magnetic field and the Hall term effect vanishing limit, the generalized Elsässer variables are found to be the most suitable for avoiding problems with singularities in the standard magnetohydrodynamic limit.

  2. Sex-linked dominant

    Science.gov (United States)

    Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... can be either an autosomal chromosome or a sex chromosome. It also depends on whether the trait ...

  3. Dominant modal decomposition method

    Science.gov (United States)

    Dombovari, Zoltan

    2017-03-01

    The paper deals with the automatic decomposition of experimental frequency response functions (FRF's) of mechanical structures. The decomposition of FRF's is based on the Green function representation of free vibratory systems. After the determination of the impulse dynamic subspace, the system matrix is formulated and the poles are calculated directly. By means of the corresponding eigenvectors, the contribution of each element of the impulse dynamic subspace is determined and the sufficient decomposition of the corresponding FRF is carried out. With the presented dominant modal decomposition (DMD) method, the mode shapes, the modal participation vectors and the modal scaling factors are identified using the decomposed FRF's. Analytical example is presented along with experimental case studies taken from machine tool industry.

  4. Tuning of a Proportional-Integral-Derivative Controller using Multi-Objective Non Dominated Sorting Particle Swarm Optimization Applied to pH Control in Continuous Stirred Tank Reactor

    Directory of Open Access Journals (Sweden)

    C. A. Kumar

    2011-01-01

    Full Text Available Problem statement: Most of the control engineering problems are characterized by several, contradicting, conflicting objectives, which have to be satisfied simultaneously. Two widely used methods for finding the optimal solution to such problems are aggregating to a single criterion and using Pareto-optimal solutions. Approach: Non-Dominated Sorting Particle Swarm Optimization algorithm (NSPSO based approach is used in the design of multiobjective PID controller to find the constant proportional-integral-derivative gains for a chemical neutralization plant. The plant considered in this study is highly non-linear and with varying time delay, provides a challenging test bed for nonlinear control problems. Results: Experimental results confirm that a multi-objective, Paretobased GA search gives a better performance than a single objective GA. Conclusion: Finally, the results for single objective and multiobjective optimization using NSPSO for the neutralization plant are compared. Gain scheduled PID controllers are designed from Pareto front obtained with NSPSO which exhibit good disturbance rejection capability.

  5. A parametric study for the generation of ion Bernstein modes from a discrete spectrum to a continuous one in the inner magnetosphere. II. Particle-in-cell simulations

    Science.gov (United States)

    Sun, Jicheng; Gao, Xinliang; Lu, Quanming; Chen, Lunjin; Tao, Xin; Wang, Shui

    2016-02-01

    In this paper, we perform one-dimensional particle-in-cell simulations to investigate the properties of perpendicular magnetosonic waves in a plasma system consisting of three components: cool electrons, cool protons, and tenuous ring distribution protons, where the waves are excited by the tenuous proton ring distribution. Consistent with the linear theory, the spectra of excited magnetosonic waves can change from discrete to continuous due to the overlapping of adjacent unstable wave modes. The increase of the proton to electron mass ratio, the ratio of the light speed to the Alfven speed, or the concentration of protons with a ring distribution tends to result in a continuous spectrum of magnetosonic waves, while the increase of the ring velocity of the tenuous proton ring distribution leads to a broader one, but with a discrete structure. Moreover, the energization of both cool electrons and protons and the scattering of ring distribution protons due to the excited magnetosonic waves are also observed in our simulations, which cannot be predicted by the linear theory. Besides, a thermalized proton ring distribution may lead to the further excitation of several lower discrete harmonics with their frequencies about several proton gyrofrequencies.

  6. Study of the L-mode tokamak plasma "shortfall" with local and global nonlinear gyrokinetic δf particle-in-cell simulation

    Science.gov (United States)

    Chowdhury, J.; Wan, Weigang; Chen, Yang; Parker, Scott E.; Groebner, Richard J.; Holland, C.; Howard, N. T.

    2014-11-01

    The δ f particle-in-cell code GEM is used to study the transport "shortfall" problem of gyrokinetic simulations. In local simulations, the GEM results confirm the previously reported simulation results of DIII-D [Holland et al., Phys. Plasmas 16, 052301 (2009)] and Alcator C-Mod [Howard et al., Nucl. Fusion 53, 123011 (2013)] tokamaks with the continuum code GYRO. Namely, for DIII-D the simulations closely predict the ion heat flux at the core, while substantially underpredict transport towards the edge; while for Alcator C-Mod, the simulations show agreement with the experimental values of ion heat flux, at least within the range of experimental error. Global simulations are carried out for DIII-D L-mode plasmas to study the effect of edge turbulence on the outer core ion heat transport. The edge turbulence enhances the outer core ion heat transport through turbulence spreading. However, this edge turbulence spreading effect is not enough to explain the transport underprediction.

  7. Gyrokinetic simulation of internal kink modes

    Energy Technology Data Exchange (ETDEWEB)

    Naitou, Hiroshi; Tsuda, Kenji [Yamaguchi Univ., Ube (Japan). Dept. of Electrical and Electronical Engineering; Lee, W.W. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Sydora, R.D. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics

    1995-05-01

    Internal disruption in a tokamak has been simulated using a three-dimensional magneto-inductive gyrokinetic particle code. The code operates in both the standard gyrokinetic mode (total-f code) and the fully nonlinear characteristic mode ({delta}f code). The latter, a recent addition, is a quiet low noise algorithm. The computational model represents a straight tokamak with periodic boundary conditions in the toroidal direction. The plasma is initially uniformly distributed in a square cross section with perfectly conducting walls. The linear mode structure of an unstable m = 1 (poloidal) and n = 1 (toroidal) kinetic internal kink mode is clearly observed, especially in the {delta}f code. The width of the current layer around the x-point, where magnetic reconnection occurs, is found to be close to the collisionless electron skin depth. This is consistent with the theory in which electron inertia has a dominant role. The nonlinear behavior of the mode is found to be quite similar for both codes. Full reconnection in the Alfven time scale is observed along with the electrostatic potential structures created during the full reconnection phase. The E x B drift due to this electrostatic potential dominates the nonlinear phase of the development after the full reconnection.

  8. Topics on domination

    CERN Document Server

    Hedetniemi, ST

    1991-01-01

    The contributions in this volume are divided into three sections: theoretical, new models and algorithmic. The first section focuses on properties of the standard domination number &ggr;(G), the second section is concerned with new variations on the domination theme, and the third is primarily concerned with finding classes of graphs for which the domination number (and several other domination-related parameters) can be computed in polynomial time.

  9. Dominance in domestic dogs

    NARCIS (Netherlands)

    Borg, Van Der J.A.M.; Schilder, M.B.H.; Vinke, C.M.; Vries, De Han; Petit, Odile

    2015-01-01

    A dominance hierarchy is an important feature of the social organisation of group living animals. Although formal and/or agonistic dominance has been found in captive wolves and free-ranging dogs, applicability of the dominance concept in domestic dogs is highly debated, and quantitative data are

  10. Total well dominated trees

    DEFF Research Database (Denmark)

    Finbow, Arthur; Frendrup, Allan; Vestergaard, Preben D.

    cardinality then G is a total well dominated graph. In this paper we study composition and decomposition of total well dominated trees. By a reversible process we prove that any total well dominated tree can both be reduced to and constructed from a family of three small trees....

  11. Dominance in domestic dogs

    NARCIS (Netherlands)

    Borg, Van Der J.A.M.; Schilder, M.B.H.; Vinke, C.M.; Vries, De Han; Petit, Odile

    2015-01-01

    A dominance hierarchy is an important feature of the social organisation of group living animals. Although formal and/or agonistic dominance has been found in captive wolves and free-ranging dogs, applicability of the dominance concept in domestic dogs is highly debated, and quantitative data are

  12. Dominating Sets and Domination Polynomials of Paths

    Directory of Open Access Journals (Sweden)

    Saeid Alikhani

    2009-01-01

    Full Text Available Let G=(V,E be a simple graph. A set S⊆V is a dominating set of G, if every vertex in V\\S is adjacent to at least one vertex in S. Let 𝒫ni be the family of all dominating sets of a path Pn with cardinality i, and let d(Pn,j=|𝒫nj|. In this paper, we construct 𝒫ni, and obtain a recursive formula for d(Pn,i. Using this recursive formula, we consider the polynomial D(Pn,x=∑i=⌈n/3⌉nd(Pn,ixi, which we call domination polynomial of paths and obtain some properties of this polynomial.

  13. Single particle mass spectral signatures from vehicle exhaust particles and the source apportionment of on-line PM2.5 by single particle aerosol mass spectrometry.

    Science.gov (United States)

    Yang, Jian; Ma, Shexia; Gao, Bo; Li, Xiaoying; Zhang, Yanjun; Cai, Jing; Li, Mei; Yao, Ling'ai; Huang, Bo; Zheng, Mei

    2017-09-01

    In order to accurately apportion the many distinct types of individual particles observed, it is necessary to characterize fingerprints of individual particles emitted directly from known sources. In this study, single particle mass spectral signatures from vehicle exhaust particles in a tunnel were performed. These data were used to evaluate particle signatures in a real-world PM2.5 apportionment study. The dominant chemical type originating from average positive and negative mass spectra for vehicle exhaust particles are EC species. Four distinct particle types describe the majority of particles emitted by vehicle exhaust particles in this tunnel. Each particle class is labeled according to the most significant chemical features in both average positive and negative mass spectral signatures, including ECOC, NaK, Metal and PAHs species. A single particle aerosol mass spectrometry (SPAMS) was also employed during the winter of 2013 in Guangzhou to determine both the size and chemical composition of individual atmospheric particles, with vacuum aerodynamic diameter (dva) in the size range of 0.2-2μm. A total of 487,570 particles were chemically analyzed with positive and negative ion mass spectra and a large set of single particle mass spectra was collected and analyzed in order to identify the speciation. According to the typical tracer ions from different source types and classification by the ART-2a algorithm which uses source fingerprints for apportioning ambient particles, the major sources of single particles were simulated. Coal combustion, vehicle exhaust, and secondary ion were the most abundant particle sources, contributing 28.5%, 17.8%, and 18.2%, respectively. The fraction with vehicle exhaust species particles decreased slightly with particle size in the condensation mode particles. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Size distribution of particle-associated polybrominated diphenyl ethers (PBDEs) and their implications for health

    Science.gov (United States)

    Lyu, Yan; Xu, Tingting; Li, Xiang; Cheng, Tiantao; Yang, Xin; Sun, Xiaomin; Chen, Jianmin

    2016-03-01

    In order to better understand the size distribution of particle-associated PBDEs and their deposition pattern in the human respiratory tract, we carried out a 1-year campaign during 2012-2013 for the measurement of size-resolved particles at the urban site of Shanghai. The results showed that particulate PBDEs exhibited a bimodal distribution with a mode peak in the accumulation particle size range and the second mode peak in the coarse particle size ranges. As the number of bromine atoms in the molecule increases, accumulation-mode peak intensity increased while coarse-mode peak intensity decreased. This change was consistent with the variation of PBDEs' subcooled vapor pressure. Absorption and adsorption processes dominated the distribution of PBDEs among the different size particles. The evaluated deposition flux of Σ13 PBDEs was 26.8 pg h-1, in which coarse particles contributed most PBDEs in head and tracheobronchial regions, while fine-mode particles contributed major PBDEs in the alveoli region. In association with the fact that fine particles can penetrate deeper into the respiratory system, fine-particle-bound highly brominated PBDEs can be inhaled more deeply into human lungs and cause a greater risk to human health.

  15. Particle-size distribution of polybrominated diphenyl ethers (PBDEs) and its implications for health

    Science.gov (United States)

    Lyu, Y.; Xu, T.; Li, X.; Cheng, T.; Yang, X.; Sun, X.; Chen, J.

    2015-12-01

    In order better to understand the particle-size distribution of particulate PBDEs and their deposition pattern in human respiratory tract, we made an one year campaign 2012-2013 for the measurement of size-resolved aerosol particles at Shanghai urban site. The results showed that particulate PBDEs exhibited a bimodal distribution with a mode peak in the accumulation particle size range and the second mode peak in the coarse particle size ranges. As the number of bromine atoms in the molecule increased, accumulation mode peak intensity increased while coarse mode peak intensity decreased. This change was the consistent with the variation of PBDEs' sub-cooled vapor pressure. Absorption and adsorption process dominated the distribution of PBDEs among the different size particles. Evaluated deposition flux of Σ13PBDE was 26.8 pg h-1, in which coarse particles contributed most PBDEs in head and tracheobronchial regions, while fine mode particles contributed major PBDEs in the alveoli region. In associated with the fact that fine particles can penetrate deeper into the respiratory system, fine particle-bound highly brominated PBDEs can be inhaled more deeply into human lungs and cause a greater risk to human health.

  16. In-situ studies on volatile jet exhaust particle emissions - impacts of fuel sulfur content and environmental conditions on nuclei-mode aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, F.; Baumann, R.; Petzold, A.; Busen, R.; Schulte, P.; Fiebig, M. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Brock, C.A. [Denver Univ., CO (United States). Dept. of Engineering

    2000-02-01

    In-situ measurements of ultrafine aerosol particle emissions were performed at cruise altitudes behind the DLR ATTAS research jet (RR M45H M501 engines) and a B737-300 aircraft (CFM56-3B1 engines). Measurements were made 0.15-20 seconds after emission as the source aircraft burned fuel with sulfur contents (FSC) of 2.6, 56 or 118 mg kg{sup -1}. Particle size distributions of from 3 to 60 nm diameter were determined using CN-counters with varying lower size detection limits. Volatile particle concentrations in the aircraft plumes strongly increased as diameter decreased toward the sizes of large molecular clusters, illustrating that apparent particle emissions are extremely sensitive to the smallest particle size detectable by the instrument used. Environmental conditions and plume age alone could influence the number of detected ultrafine (volatile) aerosols within an order of magnitude, as well. The observed volatile particle emissions decreased nonlinearly as FSC decreased to 60 mg kg{sup -1}, reaching minimum values of about 2 x 10{sup 17} kg{sup -1} and 2 x 10{sup 16} kg{sup -1} for particles >3 nm and >5 nm, respectively. Volatile particle emissions did not change significantly as FSCs were further reduced below 60 mg kg{sup -1}. Volatile particle emissions did not differ significantly between the two studied engine types. In contrast, soot particle emissions from the modern CFM56-3B1 engines were 4-5 times less (4 x 10{sup 14} kg{sup -1}) than from the older RR M45H M501 engines (1.8 x 10{sup 15} kg{sup -1}). Contrail processing has been identified as an efficient sink/quenching parameter for ultrafine particles and reduces the remaining interstitial aerosol by factors 2-10 depending on particle size.

  17. Characteristics of particle number and mass emissions during heavy-duty diesel truck parked active DPF regeneration in an ambient air dilution tunnel

    Science.gov (United States)

    Yoon, Seungju; Quiros, David C.; Dwyer, Harry A.; Collins, John F.; Burnitzki, Mark; Chernich, Donald; Herner, Jorn D.

    2015-12-01

    Diesel particle number and mass emissions were measured during parked active regeneration of diesel particulate filters (DPF) in two heavy-duty diesel trucks: one equipped with a DPF and one equipped with a DPF + SCR (selective catalytic reduction), and compliant with the 2007 and 2010 emission standards, respectively. The emission measurements were conducted using an ambient air dilution tunnel. During parked active regeneration, particulate matter (PM) mass emissions measured from a 2007 technology truck were significantly higher than the emissions from a 2010 technology truck. Particle number emissions from both trucks were dominated by nucleation mode particles having a diameter less than 50 nm; nucleation mode particles were orders of magnitude higher than accumulation mode particles having a diameter greater than 50 nm. Accumulation mode particles contributed 77.8 %-95.8 % of the 2007 truck PM mass, but only 7.3 %-28.2 % of the 2010 truck PM mass.

  18. Phenomenology of break-up modes in contact free externally heated nanoparticle laden fuel droplets

    Science.gov (United States)

    Pathak, Binita; Basu, Saptarshi

    2016-12-01

    We study thermally induced atomization modes in contact free (acoustically levitated) nanoparticle laden fuel droplets. The initial droplet size, external heat supplied, and suspended particle concentration (wt. %) in droplets govern the stability criterion which ultimately determines the dominant mode of atomization. Pure fuel droplets exhibit two dominant modes of breakup namely primary and secondary. Primary modes are rather sporadic and normally do not involve shape oscillations. Secondary atomization however leads to severe shape deformations and catastrophic intense breakup of the droplets. The dominance of these modes has been quantified based on the external heat flux, dynamic variation of surface tension, acoustic pressure, and droplet size. Addition of particles alters the regimes of the primary and secondary atomization and introduces bubble induced boiling and bursting. We analyze this new mode of atomization and estimate the time scale of bubble growth up to the point of bursting using energy balance to determine the criterion suitable for parent droplet rupture. All the three different modes of breakup have been well identified in a regime map determined in terms of Weber number and the heat utilization rate which is defined as the energy utilized for transient heating, vaporization, and boiling in droplets.

  19. Quasilinear saturation of the aperiodic ordinary mode streaming instability

    Energy Technology Data Exchange (ETDEWEB)

    Stockem Novo, A., E-mail: anne@tp4.rub.de; Schlickeiser, R. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum-und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Yoon, P. H. [Institute for Physical Science & Technology, University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Lazar, M. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum-und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Centre for Mathematical Plasma Astrophysics, Celestijnenlaan 200B, 3001 Leuven (Belgium); Poedts, S. [Centre for Mathematical Plasma Astrophysics, Celestijnenlaan 200B, 3001 Leuven (Belgium); Seough, J. [Faculty of Human Development, University of Toyama, 3190, Gofuku, Toyama City, Toyama 930-8555 (Japan); International Research Fellow of the Japan Society for the Promotion of Science, Tokyo (Japan)

    2015-09-15

    In collisionless plasmas, only kinetic instabilities and fluctuations are effective in reducing the free energy and scatter plasma particles, preventing an increase of their anisotropy. Solar energetic outflows into the interplanetary plasma give rise to important thermal anisotropies and counterstreaming motions of plasma shells, and the resulting instabilities are expected to regulate the expansion of the solar wind. The present paper combines quasilinear theory and kinetic particle-in-cell simulations in order to study the weakly nonlinear saturation of the ordinary mode in hot counter-streaming plasmas with a temperature anisotropy as a follow-up of the paper by Seough et al. [Phys. Plasmas 22, 082122 (2015)]. This instability provides a plausible mechanism for the origin of dominating, two-dimensional spectrum of transverse magnetic fluctuations observed in the solar wind. Stimulated by the differential motion of electron counterstreams the O mode instability may convert their free large-scale energy by nonlinear collisionless dissipation on plasma particles.

  20. Autosomal dominant lamellar ichthyosis.

    Science.gov (United States)

    Toribio, J; Fernández Redondo, V; Peteiro, C; Zulaica, A; Fabeiro, J M

    1986-08-01

    Five members of two generations of one family were affected with lamellar ichthyosis, suggesting autosomal dominant transmission. The clinical and histopathological characteristics of the cases described here are similar to those reported by Traupe et al. (1984) as autosomal dominant lamellar ichthyosis and thus confirm the existence of this new form of ichthyosis.

  1. Particle-size distribution of polybrominated diphenyl ethers (PBDEs and its implications for health

    Directory of Open Access Journals (Sweden)

    Y. Lyu

    2015-12-01

    tract, we made an one year campaign 2012–2013 for the measurement of size-resolved aerosol particles at Shanghai urban site. The results showed that particulate PBDEs exhibited a bimodal distribution with a mode peak in the accumulation particle size range and the second mode peak in the coarse particle size ranges. As the number of bromine atoms in the molecule increased, accumulation mode peak intensity increased while coarse mode peak intensity decreased. This change was the consistent with the variation of PBDEs' sub-cooled vapor pressure. Absorption and adsorption process dominated the distribution of PBDEs among the different size particles. Evaluated deposition flux of Σ13PBDE was 26.8 pg h−1, in which coarse particles contributed most PBDEs in head and tracheobronchial regions, while fine mode particles contributed major PBDEs in the alveoli region. In associated with the fact that fine particles can penetrate deeper into the respiratory system, fine particle-bound highly brominated PBDEs can be inhaled more deeply into human lungs and cause a greater risk to human health.

  2. Aerosol size distribution and new particle formation events in the suburb of Xi'an, northwest China

    Science.gov (United States)

    Peng, Yan; Liu, Xiaodong; Dai, Jin; Wang, Zhao; Dong, Zipeng; Dong, Yan; Chen, Chuang; Li, Xingmin; Zhao, Na; Fan, Chao

    2017-03-01

    Particle number concentration and size distribution are important for better understanding the characteristics of aerosols. However, their measurements are scarce in western China. Based on the first measurement of particle number size distribution (10-487 nm) in the suburb of Xi'an, northwest China from November 2013 to December 2014, the seasonal, monthly and diurnal average particle number concentrations were investigated, and the characteristics of new particle formation (NPF) events and their dependencies on meteorological parameters also discussed. The results showed that the annual average particle number concentrations in the nucleation (NNUC), Aitken (NAIT), and Accumulation (NACC) size ranges were 960 cm-3, 4457 cm-3, 3548 cm-3, respectively. The mean total particle number concentration (NTOT) was 8965 cm-3 and largely dominated by particles in Aitken mode. The number concentration was dominated by particles around 67.3 nm in spring, summer and fall, while about 89.8 nm in winter. The percentage of the ultrafine size range (UFP, particles of diameter below 100 nm) to total particle number concentration was 63.2%, 69.6%, 62.2% and 58.1% in four seasons. The diurnal variation of the nucleation mode particles was mainly influenced by NPF events in summer, while by both traffic densities and NPF events in spring, fall and winter. The diurnal variation of the number concentration of Aitken mode particles correlated with the traffic emission in spring, fall and winter, while in summer it more correlated with contribution of the growth of the nucleation mode particles. The burst of nucleation mode particles typically started in the daytime (08:15-16:05, LST). The growth rates of nucleated particles ranged from 2.8 to 10.7 nm h-1 with an average of 5.0 ± 1.9 nm h-1. Among observed 66 NPF events from 347 effective measurement days, 85 percent of their air masses came from north or northwest China, resulting in a low concentration of pre-existing particles, and

  3. Downhill Domination in Graphs

    OpenAIRE

    Haynes Teresa W.; Hedetniemi Stephen T.; Jamieson Jessie D.; Jamieson William B.

    2014-01-01

    A path π = (v1, v2, . . . , vk+1) in a graph G = (V,E) is a downhill path if for every i, 1 ≤ i ≤ k, deg(vi) ≥ deg(vi+1), where deg(vi) denotes the degree of vertex vi ∈ V. The downhill domination number equals the minimum cardinality of a set S ⊆ V having the property that every vertex v ∈ V lies on a downhill path originating from some vertex in S. We investigate downhill domination numbers of graphs and give upper bounds. In particular, we show that the downhill domination number of a grap...

  4. Influential parameters on particle exposure of pedestrians in urban microenvironments

    Science.gov (United States)

    Buonanno, G.; Fuoco, F. C.; Stabile, L.

    2011-03-01

    Exposure to particle concentrations in urban areas was evaluated in several studies since airborne particles are considered to bring about adverse health effects. Transportation modes and urban microenvironments account for the highest contributions to the overall daily particle exposure concentration. In the present study an evaluation of the influential parameters affecting particle exposure of pedestrian in urban areas is reported. Street geometry, traffic mode, wind speed and direction effects were analyzed through an experimental campaign performed in different streets of an Italian town. To this purpose a high-resolution time measurement apparatus was used in order to capture the dynamic of the freshly emitted particles. Number, surface area and mass concentrations and distributions were measured continuously along both the sides of street canyons and avenue canyons during 10-minutes walking routes. The combined effect of street geometry and wind direction may contribute strongly to dilute the fresh particles emitted by vehicles. In particular, street canyons are characterized by lower ventilation phenomena which lead to similar concentration values on both the side of the street. Higher wind speed was found to decrease concentrations in the canyon. Traffic mode also seems to influence exposure concentrations. In particular, submicrometer particle mass concentration was higher as the traffic is more congested; otherwise, coarse fraction dominates mass exposure concentration along street characterized by a more fluent traffic, showing a typical resuspension modality.

  5. Downhill Domination in Graphs

    Directory of Open Access Journals (Sweden)

    Haynes Teresa W.

    2014-08-01

    Full Text Available A path π = (v1, v2, . . . , vk+1 in a graph G = (V,E is a downhill path if for every i, 1 ≤ i ≤ k, deg(vi ≥ deg(vi+1, where deg(vi denotes the degree of vertex vi ∈ V. The downhill domination number equals the minimum cardinality of a set S ⊆ V having the property that every vertex v ∈ V lies on a downhill path originating from some vertex in S. We investigate downhill domination numbers of graphs and give upper bounds. In particular, we show that the downhill domination number of a graph is at most half its order, and that the downhill domination number of a tree is at most one third its order. We characterize the graphs obtaining each of these bounds

  6. Dominantly Inherited Nemaline Myopathy

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2003-08-01

    Full Text Available A locus on chromosome 15q21-23 for a dominantly inherited nemaline myopathy with core-like lesions is reported in two unrelated families evaluated at University Medical Center, Nijmegen, The Netherlands.

  7. Observation of new particle formation in subtropical urban environment

    Directory of Open Access Journals (Sweden)

    H. C. Cheung

    2010-10-01

    Full Text Available The aim of this study was to characterise the new particle formation events in subtropical urban environment Southern Hemisphere. The study measured the number concentration of particles and its size distribution in Brisbane, Australia during 2009. The variation of particle number concentration and nucleation burst events were studied and the particle growth rate was characterised which was first reported in urban environment of Australia. The annual average NUFP, NAitken and Nnuc were 9.3×103, 3.7×103 and 5.6×103 cm−3, respectively. Weak seasonal variation in number concentration was observed. Local vehicle emission was major contributor of the pollution observed in the morning which was dominated by the Aitken mode particles, while particle formed by secondary formation process was contributed to the particle number concentration in the afternoon. 65 nucleation burst events were identified during the study period. Nucleation burst events were classified into two groups with and without particle growth after the burst of nucleation mode particles observed. Average particle growth rate of the nucleation events was 4.6 nm hr−1 (ranged from 1.79–7.78 nm hr−1. Case studies of the nucleation burst events were characterised including i the nucleation burst with particle growth which was associated with the particle precursor emitted from local vehicle emission, ii the nucleation burst without particle growth which was due to the transport of industrial emissions from the coast to Brisbane city, and iii interplay between the above two cases which demonstrated the impact of the vehicle and industrial emissions on the variation of particle number concentration and its size distribution during the same day.

  8. Shape matters: Near-field fluid mechanics dominate the collective motions of ellipsoidal squirmers.

    Science.gov (United States)

    Kyoya, K; Matsunaga, D; Imai, Y; Omori, T; Ishikawa, T

    2015-12-01

    Microswimmers show a variety of collective motions. Despite extensive study, questions remain regarding the role of near-field fluid mechanics in collective motion. In this paper, we describe precisely the Stokes flow around hydrodynamically interacting ellipsoidal squirmers in a monolayer suspension. The results showed that various collective motions, such as ordering, aggregation, and whirls, are dominated by the swimming mode and the aspect ratio. The collective motions are mainly induced by near-field fluid mechanics, despite Stokes flow propagation over a long range. These results emphasize the importance of particle shape in collective motion.

  9. Steady- and transient-state analysis of fully ceramic microencapsulated fuel with randomly dispersed tristructural isotropic particles via two-temperature homogenized model-I: Theory and method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yoon Hee; Cho, Bum Hee; Cho, Nam Zin [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2016-06-15

    As a type of accident-tolerant fuel, fully ceramic microencapsulated (FCM) fuel was proposed after the Fukushima accident in Japan. The FCM fuel consists of tristructural isotropic particles randomly dispersed in a silicon carbide (SiC) matrix. For a fuel element with such high heterogeneity, we have proposed a two-temperature homogenized model using the particle transport Monte Carlo method for the heat conduction problem. This model distinguishes between fuel-kernel and SiC matrix temperatures. Moreover, the obtained temperature profiles are more realistic than those of other models. In Part I of the paper, homogenized parameters for the FCM fuel in which tristructural isotropic particles are randomly dispersed in the fine lattice stochastic structure are obtained by (1) matching steady-state analytic solutions of the model with the results of particle transport Monte Carlo method for heat conduction problems, and (2) preserving total enthalpies in fuel kernels and SiC matrix. The homogenized parameters have two desirable properties: (1) they are insensitive to boundary conditions such as coolant bulk temperatures and thickness of cladding, and (2) they are independent of operating power density. By performing the Monte Carlo calculations with the temperature-dependent thermal properties of the constituent materials of the FCM fuel, temperature-dependent homogenized parameters are obtained.

  10. Metal-insulator-metal waveguides for particle trapping and separation.

    Science.gov (United States)

    Khan, Saara A; Chang, Chia-Ming; Zaidi, Zain; Shin, Wonseok; Shi, Yu; Ellerbee Bowden, Audrey K; Solgaard, Olav

    2016-06-21

    Optical particle trapping and separation are essential techniques in the fields of biology and chemistry. In many applications, it is important to identify passive separation techniques that only rely on intrinsic forces in a system with a fixed device geometry. We present a dual-waveguide sorter that utilizes the loss of metal-insulator-metal (MIM) waveguides for completely passive particle trapping and separation and is created using a unique angle sidewall deposition process. Our experiments show that an inner Au-Si3N4-Au waveguide is able to trap particles within the propagation distance of its dominant modes and release the particles into an outer Au-H2O-Au waveguide. The outer waveguide then propels the particles and separates them by size. The separation results are accurately modeled by a first-principles, analytical model.

  11. Comparative phototoxicity of nanoparticulate and bulk ZnO to a free-living nematode Caenorhabditis elegans: The importance of illumination mode and primary particle size

    Energy Technology Data Exchange (ETDEWEB)

    Ma, H., E-mail: mah77@uga.edu [Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA 30602 (United States); Kabengi, N.J.; Bertsch, P.M.; Unrine, J.M. [Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546 (United States); Glenn, T.C.; Williams, P.L. [Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA 30602 (United States)

    2011-06-15

    The present study evaluated phototoxicity of nanoparticulate ZnO and bulk-ZnO under natural sunlight (NSL) versus ambient artificial laboratory light (AALL) illumination to a free-living nematode Caenorhabditis elegans. Phototoxicity of nano-ZnO and bulk-ZnO was largely dependent on illumination method as 2-h exposure under NSL caused significantly greater mortality in C. elegans than under AALL. This phototoxicity was closely related to photocatalytic reactive oxygen species (ROS) generation by the ZnO particles as indicated by concomitant methylene blue photodegradation. Both materials caused mortality in C. elegans under AALL during 24-h exposure although neither degraded methylene blue, suggesting mechanisms of toxicity other than photocatalytic ROS generation were involved. Particle dissolution of ZnO did not appear to play an important role in the toxicity observed in this study. Nano-ZnO showed greater phototoxicity than bulk-ZnO despite their similar size of aggregates, suggesting primary particle size is more important than aggregate size in determining phototoxicity. - Highlights: > Phototoxicity of nano- or bulk-ZnO was enhanced by natural sunlight illumination. > This phototoxicity was well-correlated to photocatalytic ROS generation. > Toxicity of ZnO particles not related to photocatalytic ROS generation was also observed. > Nano-ZnO showed greater phototoxicity than bulk-ZnO due to its greater total surface area per unit mass. > Primary particle size appeared to be more important than aggregate size in determining phototoxicity. - Phototoxicity of nanoparticulate and bulk ZnO was greatly enhanced by natural sunlight illumination compared to artificial laboratory light illumination.

  12. Sensitivity of aerosol properties to new particle formation mechanism and to primary emissions in a continental-scale chemical transport model

    Energy Technology Data Exchange (ETDEWEB)

    Chang,L.S.; Schwartz, S.E.; McGraw, R.; Lewis, E.R.

    2009-04-02

    Four theoretical formulations of new particle formation (NPF) and one empirical formulation are used to examine the sensitivity of observable aerosol properties to NPF formulation and to properties of emitted particles in a continental-scale model for the United States over a 1-month simulation (July 2004). For each formulation the dominant source of Aitken mode particles is NPF with only a minor contribution from primary emissions, whereas for the accumulation mode both emissions and transfer of particles from the Aitken mode are important. The dominant sink of Aitken mode number is coagulation, whereas the dominant sink of accumulation mode number is wet deposition (including cloud processing), with a minor contribution from coagulation. The aerosol mass concentration, which is primarily in the accumulation mode, is relatively insensitive to NPF formulation despite order-of-magnitude differences in the Aitken mode number concentration among the different parameterizations. The dominant sensitivity of accumulation mode number concentration is to the number of emitted particles (for constant mass emission rate). Comparison of modeled aerosol properties with aircraft measurements shows, as expected, better agreement in aerosol mass concentration than in aerosol number concentration for all NPF formulations considered. These comparisons yield instances of rather accurate simulations in the planetary boundary layer, with poor model performance in the free troposphere attributed mainly to lack of representation of biomass burning and/or to long-range transport of particles from outside the model domain. Agreement between model results and measurements is improved by using smaller grid cells (12 km versus 60 km).

  13. Dominant Voice in Hamlet

    Institute of Scientific and Technical Information of China (English)

    李丹

    2015-01-01

    <正>The Tragedy of Hamlet dramatizes the revenge Prince Hamlet exacts on his uncle Claudius for murdering King Hamlet,Claudius’s brother and Prince Hamlet’s father,and then succeeding to the throne and taking as his wife Gertrude,the old king’s widow and Prince Hamlet’s mother.This paper will discuss something about dominant voice in the play.Dominant voice is the major voice in the country,the society,or the whole world.Those people who have the power or

  14. Identification of column-integrated dominant aerosols using the archive of AERONET data set

    Directory of Open Access Journals (Sweden)

    Y. Choi

    2013-10-01

    Full Text Available Dominant aerosols were distinguished from level 2 inversion products for the Anmyon Aerosol Robotic Network (AERONET site between 1999 and 2007. Secondary inorganic ions, black carbon (BC and organic carbon (OC were separated from fine mode aerosols, and mineral dust (MD, MD mixed with carbon, mixed coarse particles were separated from coarse mode aerosols. Four parameters (aerosol optical depth, single scattering albedo, absorption Angstrom exponent, and fine mode fraction were used for this classification. Monthly variation of the occurrence rate of each aerosol type reveals that MD and MD mixed with carbon are frequent in spring. Although the fraction among dominant aerosols and occurrence rates of BC and OC tend to be high in cold season for heating, their contributions are variable but consistent due to various combustion sources. Secondary inorganic ions are most prevalent from June to August; the effective radius of these fine mode aerosols increases with water vapor content because of hygroscopic growth. To evaluate the validity of aerosol types identified, dominant aerosols at worldwide AERONET sites (Beijing, Mexico City, Goddard Space Flight Center, Mongu, Alta Floresta, Cape Verde, which have distinct source characteristics, were classified into the same aerosol types. The occurrence rate and fraction of the aerosol types at the selected sites confirm that the classification in this study is reasonable. However, mean optical properties of the aerosol types are generally influenced by the aerosol types with large fractions. The present work shows that the identification of dominant aerosols is effective even at a single site, provided that the archive of the data set is properly available.

  15. Identification of column-integrated dominant aerosols using the archive of AERONET data set

    Science.gov (United States)

    Choi, Y.; Ghim, Y. S.; Holben, B. N.

    2013-10-01

    Dominant aerosols were distinguished from level 2 inversion products for the Anmyon Aerosol Robotic Network (AERONET) site between 1999 and 2007. Secondary inorganic ions, black carbon (BC) and organic carbon (OC) were separated from fine mode aerosols, and mineral dust (MD), MD mixed with carbon, mixed coarse particles were separated from coarse mode aerosols. Four parameters (aerosol optical depth, single scattering albedo, absorption Angstrom exponent, and fine mode fraction) were used for this classification. Monthly variation of the occurrence rate of each aerosol type reveals that MD and MD mixed with carbon are frequent in spring. Although the fraction among dominant aerosols and occurrence rates of BC and OC tend to be high in cold season for heating, their contributions are variable but consistent due to various combustion sources. Secondary inorganic ions are most prevalent from June to August; the effective radius of these fine mode aerosols increases with water vapor content because of hygroscopic growth. To evaluate the validity of aerosol types identified, dominant aerosols at worldwide AERONET sites (Beijing, Mexico City, Goddard Space Flight Center, Mongu, Alta Floresta, Cape Verde), which have distinct source characteristics, were classified into the same aerosol types. The occurrence rate and fraction of the aerosol types at the selected sites confirm that the classification in this study is reasonable. However, mean optical properties of the aerosol types are generally influenced by the aerosol types with large fractions. The present work shows that the identification of dominant aerosols is effective even at a single site, provided that the archive of the data set is properly available.

  16. Dominant cystoid macular dystrophy

    NARCIS (Netherlands)

    Saksens, N.T.M.; Huet, R.A.C. van; Lith-Verhoeven, J.J. van; Hollander, A.I. den; Hoyng, C.B.; Boon, C.J.

    2015-01-01

    OBJECTIVE: To describe the clinical characteristics and long-term follow-up in patients with autosomal dominant cystoid macular dystrophy (DCMD). DESIGN: Retrospective case series. PARTICIPANTS: Ninety-seven patients with DCMD. METHODS: Extensive ophthalmic examination, including visual acuity (VA),

  17. Iron dominated magnets

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, G.E.

    1985-07-01

    These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of the subjects design and construction. The material is arranged in the categories: General Concepts and Cost Considerations, Profile Configuration and Harmonics, Magnetic Measurements, a few examples of ''special magnets'' and Materials and Practices. Extensive literature is provided.

  18. discourse of domination

    African Journals Online (AJOL)

    suffering justifies the position and work of The Bank and other social forces with similar ... include accounts of the growing and increasingly interwoven resistance in .... tural domination or as parasites able to feed off a social body weakened by the ... through objective analysis of poor people's descriptions of their realities'.

  19. Searching for world domination

    CERN Multimedia

    Quillen, E

    2004-01-01

    "Optimists might believe Microsoft suffered a setback last week that will impede its progress toward world domination, but I suspect the company has already found a way to prevail. At issue before the European Union was Microsoft's bundling of its Windows Media Player with its operating system" (1 page)

  20. Autosomal dominant osteopetrosis revisited

    DEFF Research Database (Denmark)

    Bollerslev, Jens; Henriksen, Kim; Nielsen, Morten Frost Munk

    2013-01-01

    Systematic studies of autosomal dominant osteopetrosis (ADO) were followed by the identification of underlying mutations giving unique possibilities to perform translational studies. What was previously designated ADO1 turned out to be a high bone mass phenotype caused by a missense mutation...

  1. Dominant optic atrophy

    DEFF Research Database (Denmark)

    Lenaers, Guy; Hamel, Christian; Delettre, Cécile

    2012-01-01

    DEFINITION OF THE DISEASE: Dominant Optic Atrophy (DOA) is a neuro-ophthalmic condition characterized by a bilateral degeneration of the optic nerves, causing insidious visual loss, typically starting during the first decade of life. The disease affects primary the retinal ganglion cells (RGC...

  2. Pulse-shape discrimination of scintillation from alpha and beta particles with liquid scintillator and Geiger-mode multipixel avalanche diodes

    CERN Document Server

    Kreslo, I; Delaquis, S; Ereditato, A; Janos, S; Messina, M; Moser, U; Rossi, B; Zeller, M

    2011-01-01

    A successfull application of Geiger-mode multipixel avalanche diodes (GMAPDs) for pulse-shape discrimination in alpha-beta spectrometry using organic liquid scintillator is described in this paper. Efficient discrimination of alpha and beta components in the emission of radioactive isotopes is achieved for alpha energies above 0.3 MeV. The ultra-compact design of the scintillating detector helps to efficiently suppress cosmic-ray and ambient radiation background. This approach allows construction of hand-held robust devices for monitoring of radioactive contamination in various environmental conditions.

  3. The effect of particle size, morphology and C-rates on 3D structured Co3O4 inverse opal conversion mode anode materials

    Science.gov (United States)

    McNulty, David; Geaney, Hugh; Carroll, Elaine; Garvey, Shane; Lonergan, Alex; O’Dwyer, Colm

    2017-02-01

    Engineering Co3O4 nanoparticles into highly ordered, 3D inverse opal (IO) structures is shown to significantly improve their performance as more efficient conversion mode Li-ion anode materials. By comparison with Co3O4 microparticles, the advantages of the porous anode architecture are clearly shown. The inverse opal material markedly enhances specific capacity and capacity retention. The impact of various C rates on the rate of the initial charge demonstrates that higher rate charging (10 C) was much less destructive to the inverse opal structure than charging at a slow rate (0.1 C). Slower C rates that affect the IO structure resulted in higher specific capacities (more Li2O) as well as improved capacity retention. The IO structures cycle as CoO, which improves Coulombic efficiency and limits volumetric changes, allowing rate changes more efficiently. This work demonstrates how 3D IOs improve conversion mode anode material performance in the absence of additive or binders, thus enhancing mass transport of Li2O charge–discharge product through the open structure. This effect mitigates clogging by structural changes at slow rates (high capacity) and is beneficial to the overall electrochemical performance.

  4. Particle Emissions from Biomass Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Szpila, Aneta; Bohgard, Mats [Lund Inst. of Technology (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Div. of Bioenergy Technology; Pagels, Joakim; Rissler, Jenny; Swietlicki, Erik; Gharibi, Arash [Lund Univ. (Sweden). Div. of Nuclear Physics

    2003-05-01

    particle number concentration increased slightly with increasing load, at the same time the fine mode particles became smaller. This was probably caused by different degree of particle coagulation as the residence time in the boiler was changed. The mean diameter during combustion of forest residue was around 100 nm compared to 70-80 nm for dry wood and pellets, while the total number was close to constant. This explains the differences in mass concentration found in the impactor measurements. The concentrations of CO and THC was highest for the dry wood fuel, the PAH concentration was highest for pellets combustion in boiler 4, however this boiler was poorly tuned at the time of measurement. The PAH concentration was 5 times higher during combustion of dry wood compared to forest residue. The concentration of CO, THC and PAH varied to a great extend. The high concentrations were measured in boilers running at a low load. The concentration of particle organic carbon was less than 15% of PMI for all fuels. However we used heated primary dilution, which inhibits the condensation of organic components into, the particle phase. A significant fraction of the emitted organic carbon may condense to the particle phase during dilution after the stack or after being oxidized in the atmosphere. We also measured elemental carbon in the particle phase. The contribution to PM1 was as high as 25-30% during pellets combustion at low load and 8% at low load during combustion of dry wood. In all other cases the EC-concentration was less than 3% of PMI. PIXE and lon-chromatography confirmed that alkali-salts were the dominant chemical species. PIXE analysis revealed that emitted amounts of heavy metals such as Zn, Cd and Pb are strongly dependent on the type of the fuel used. Forest residues gave high emissions of Zn, Cd and Pb, while pellets gave very high emissions of Cd and Zn. The fuel with the lowest emissions of heavy metals was dry wood. This again could be related to ash content in

  5. Impact of fine particle content on mode and scale of slope instability of debris flow%细粒含量对泥石流斜坡失稳模式与规模的影响

    Institute of Scientific and Technical Information of China (English)

    王志兵; 李凯; 汪稔; 胡明鉴

    2016-01-01

    In order to study the impact of fine particles ( d≤0. 075 mm) of the soil body of debris flow on the inoculation and startup mechanisms of debris flow during the rainfall infiltration and interstitial flow processes, an experiment on slope debris flow induced by artificial rainfall, using a self-made debris flow model tank and an indoor slope model made of three kinds of fine particle soil bodies, was carried out. The experiment studied the formation characteristics of slope runoff, soil erosion characteristics, and slope instability modes of the soil body of debris flow during the rainfall infiltration process. The experimental results show that fine particles of the slope will disperse, drain, and cause coarsening of the surface soil of the slope. The dispersed fine particles of a slope with high fine particle content will migrate to depth, block the holes, and decrease the permeability ( infiltration capacity) of the slope soil, inducing slope runoff and slope failure before the wetting front extends to the lower soil-rock interface, with the failure surface being close to the wetting front ( only a few centimeters away) . The failure mode can be described as sliding-flowing failure of the block at first, and then gully erosion. The scale of soil erosion is related to the rainfall intensity and fine particle content. The failure mode of slope soil with low fine particle content can be described as retrogressive slumping. However, in the experimental process, no massive soil loss occurs, the blockage in the holes of soil with low fine particle content caused by the dispersion and migration of fine particles is not significant, and relatively stable flow with fine particles forms at the soil-rock inter-surface. The fine particle content of the slope soil is important to the slope failure mode and formation of the slope runoff. The security coefficient obtained from the slope stability analysis model considering the impact of the slope runoff shows better

  6. Excursions through KK modes

    Science.gov (United States)

    Furuuchi, Kazuyuki

    2016-07-01

    In this article we study Kaluza-Klein (KK) dimensional reduction of massive Abelian gauge theories with charged matter fields on a circle. Since local gauge transformations change position dependence of the charged fields, the decomposition of the charged matter fields into KK modes is gauge dependent. While whole KK mass spectrum is independent of the gauge choice, the mode number depends on the gauge. The masses of the KK modes also depend on the field value of the zero-mode of the extra dimensional component of the gauge field. In particular, one of the KK modes in the KK tower of each massless 5D charged field becomes massless at particular values of the extra-dimensional component of the gauge field. When the extra-dimensional component of the gauge field is identified with the inflaton, this structure leads to recursive cosmological particle productions.

  7. An Hourglass Control Algorithm for Lagrangian Smooth Particle Hydrodynamics

    CERN Document Server

    Ganzenmüller, Georg C

    2014-01-01

    This paper presents a stabilization scheme which addresses the rank-deficiency problem in meshless collocation methods for solid mechanics. Specifically, Smooth-Particle Hydrodynamics (SPH) in the Total Lagrangian formalism is considered. This method is rank-deficient in the sense that the SPH approximation of the deformation gradient is not unique with respect to the positions of the integration points. The non-uniqueness can result in the formation of zero-energy modes. If undetected, these modes can grow and completely dominate the solution. Here, an algorithm is introduced, which effectively suppresses these modes in a fashion similar to hour-glass control mechanisms in Finite-Element methods. Simulations utilizing this control algorithm result exhibit much improved stability, accuracy, and error convergence properties. In contrast to an alternative method which eliminates zero-energy modes, namely the use of additional integration points, the here presented algorithm is easy to implement and computationa...

  8. Test beam results of micro channel plates in 'ionisation mode' for the detection of single charged particle and electromagnetic showers

    Energy Technology Data Exchange (ETDEWEB)

    Barnyakov, A.; Barnyakov, M. [Budker Institute of Nuclear Physics, pr. Akademika Lavrentieva, 11, Novosibirsk, (Russian Federation); Novosibirsk State University, str. Pirogova 2, Novosibirsk, (Russian Federation); Brianza, L.; Ghezzi, A.; Gotti, C.; Govoni, P.; Martelli, A.; Marzocchi, B.; Pigazzini, S.; Tabarelli de Fatis, T.; Trevisani, N. [Universita di Milano Bicocca and INFN, Sezione di Milano-Bicocca,, Piazza della Scienza 3, I-20126, Milano, (Italy); Cavallari, F.; Del Re, D.; Gelli, S.; Jorda Lope, C.; Meridiani, P.; Organtini, G.; Paramatti, R.; Pernie, L.; Rahatlou, S.; Rovelli, C.; Santanastasio, F. [Universita di Roma ' La Sapienza' and INFN, Sezione di Roma1, P.le A. Moro 1, I-00044 Rome, (Italy)

    2015-07-01

    IMCP is an R and D project aimed at the exploitation of secondary emission of electrons from the surface of microchannel plates (MCP) for fast timing of showers in high rate environments. The usage of MCPs in 'ionisation' mode has long been proposed and is used extensively in ion time-of-flight mass spectrometers. What has not been investigated in depth is their use to detect the ionizing component of showers. The fast time resolution of MCPs exceeds anything that has been previously used in calorimeters, and, if exploited effectively, could aid in the event reconstruction at high luminosities. Results from tests with electrons with energies up to 150 GeV of MCP devices with different characteristics will be presented, in particular detection efficiency and time resolution. (authors)

  9. Dominance of pollutant aerosols over an urban region and its impact on boundary layer temperature profile

    Science.gov (United States)

    Talukdar, Shamitaksha; Jana, Soumyajyoti; Maitra, Animesh

    2017-01-01

    Collocated measurements of aerosol optical depth (AOD) and black carbon at different wavelengths over Kolkata, an urban region in eastern India, have been used to calculate aerosol single-scattering albedo (SSA). The wavelength dependence of SSA and AOD has been presented to discriminate the aerosol types over this highly populated metropolitan area. The spectral pattern shows that SSA decreases with wavelength for most of the time in a year and corresponding Ångström coefficient is greater than unity. These optical properties indicate the dominance of fine-mode pollutant particles over the city. The temperature lapse rate profile within the surface boundary layer has been found to be significantly influenced by the heating effect of fine-mode pollutants, and consequently, the growth of the convective processes in the lower troposphere is notably affected. In addition, a back trajectory analysis has also been presented to indicate that transported air masses can have significant impact on spectral pattern of SSA.

  10. Dominating biological networks.

    Directory of Open Access Journals (Sweden)

    Tijana Milenković

    Full Text Available Proteins are essential macromolecules of life that carry out most cellular processes. Since proteins aggregate to perform function, and since protein-protein interaction (PPI networks model these aggregations, one would expect to uncover new biology from PPI network topology. Hence, using PPI networks to predict protein function and role of protein pathways in disease has received attention. A debate remains open about whether network properties of "biologically central (BC" genes (i.e., their protein products, such as those involved in aging, cancer, infectious diseases, or signaling and drug-targeted pathways, exhibit some topological centrality compared to the rest of the proteins in the human PPI network.To help resolve this debate, we design new network-based approaches and apply them to get new insight into biological function and disease. We hypothesize that BC genes have a topologically central (TC role in the human PPI network. We propose two different concepts of topological centrality. We design a new centrality measure to capture complex wirings of proteins in the network that identifies as TC those proteins that reside in dense extended network neighborhoods. Also, we use the notion of domination and find dominating sets (DSs in the PPI network, i.e., sets of proteins such that every protein is either in the DS or is a neighbor of the DS. Clearly, a DS has a TC role, as it enables efficient communication between different network parts. We find statistically significant enrichment in BC genes of TC nodes and outperform the existing methods indicating that genes involved in key biological processes occupy topologically complex and dense regions of the network and correspond to its "spine" that connects all other network parts and can thus pass cellular signals efficiently throughout the network. To our knowledge, this is the first study that explores domination in the context of PPI networks.

  11. Characterization of new particle and secondary aerosol formation during summertime in Beijing, China

    Science.gov (United States)

    Zhang, Y. M.; Zhang, X. Y.; Sun, J. Y.; Lin, W. L.; Gong, S. L.; Shen, X. J.; Yang, S.

    2011-07-01

    Size-resolved aerosol number and mass concentrations and the mixing ratios of O3 and various trace gases were continuously measured at an urban station before and during the Beijing Olympic and Paralympic Games (5 June to 22 September, 2008). 23 new particle formation (NPF) events were identified; these usually were associated with changes in wind direction and/or rising concentrations of gas-phase precursors or after precipitation events. Most of the NPF events started in the morning and continued to noon as particles in the nucleation mode grew into the Aitken mode. From noon to midnight, the aerosols grew into the accumulation mode through condensation and coagulation. Ozone showed a gradual rise starting around 10:00 local time, reached its peak around 15:00 and then declined as the organics increased. The dominant new particle species were organics (40-75% of PM1) and sulphate; nitrate and ammonium were more minor contributors.

  12. Characterization of new particle and secondary aerosol formation during summertime in Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y. M. (Key Laboratory for Atmospheric Chemistry, Centre for Atmosphere Watch and Services, Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing (China); Graduate Univ. of Chinese Academy of Sciences, Beijing (China)); Zhang, X. Y.; Sun, J. Y.; Lin, W. L.; Shen, X. J. (Key Laboratory for Atmospheric Chemistry, Centre for Atmosphere Watch and Services, Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing (China)), e-mail: xiaoye@cams.cma.gov.cn; Gong, S. L. (Air Quality Research Div., Science and Technology Branch, Environment Canada, Toronto (Canada)); Yang, S. (State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Inst. of Atmospheric Physics, CAS, Beijing (China))

    2011-07-15

    Size-resolved aerosol number and mass concentrations and the mixing ratios of O{sub 3} and various trace gases were continuously measured at an urban station before and during the Beijing Olympic and Paralympic Games (5 June to 22 September, 2008). 23 new particle formation (NPF) events were identified; these usually were associated with changes in wind direction and/or rising concentrations of gas-phase precursors or after precipitation events. Most of the NPF events started in the morning and continued to noon as particles in the nucleation mode grew into the Aitken mode. From noon to midnight, the aerosols grew into the accumulation mode through condensation and coagulation. Ozone showed a gradual rise starting around 10:00 local time, reached its peak around 15:00 and then declined as the organics increased. The dominant new particle species were organics (40-75% of PM{sub 1}) and sulphate; nitrate and ammonium were more minor contributors

  13. Challenging Credit Dominance

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ Europe's widening sovereign debt crisis has brought independent credit ratings to the forefront of the EU's agenda.To directly address the mat ter,the EU announced plans to set up a European creditrating authority for sovereign debt ratings on April 30.This marked a milestone in the international credit history,and the beginning of changes to U.S.-dominated international credit ratings and the pattern of international politics and economics,said Sun Zhe,Director of the Center for U.S.

  14. 演化过程主导的流体力学模型与Cu-Cu在BNL-RHIC能量碰撞中带电粒子的赝快度分布%Evolution-dominated Hydrodynamic Model and the Pseudorapidity Distributions of the Charged Particles Pro duced in Cu-Cu Collisions at BNL-RHIC Energies

    Institute of Scientific and Technical Information of China (English)

    姜志进; 王杰; 张海丽; 马可

    2014-01-01

    The charged particles resulting in high energy heavy ion collisions consist of two parts: One is from the hot and dense matter produced in collisions. The other is the leading particles. We suppose that the hot and dense matter expands and freezes out into the charged particles according to the evolution-dominated hydrodynamics, and the leading particles are from participants with approximately the same energy. On the basis of this assumption, we get the pseudorapidity distributions of the charged particles produced in high energy heavy ion collisions, and make a comparison with the experimental data presented by PHOBOS Collaboration at BNL-RHIC in Cu-Cu collisions at√sNN=62.4 and 200 GeV. The theoretical predictions are in good accordance with experimental measurements.%高能重离子碰撞产生的带电粒子由两部分组成:一部分来源于碰撞产生的高温高密度物质,另一部分是带头粒子。假设高温高密度物质按照由演化过程主导的流体力学的规律膨胀并冻析为带电粒子,带头粒子来源于参与者且具有大致相同的能量。基于该假设,得到了高能重离子碰撞带电粒子的赝快度分布,并与BNL-RHIC上的PHOBOS合作组在√sNN=62.4与200 GeV的Cu-Cu碰撞中给出的实验结果相比较,理论与实验测量符合得很好。

  15. On gas and particle radiation in pulverized fuel combustion furnaces

    DEFF Research Database (Denmark)

    Yin, Chungen

    2015-01-01

    Radiation is the principal mode of heat transfer in a combustor. This paper presents a refined weighted sum of gray gases model for computational fluid dynamics modelling of conventional air-fuel combustion, which has greater accuracy and completeness than the existing gaseous radiative property....... Although the refined gaseous radiative property model shows great advantages in gaseous fuel combustion modelling, its impacts are largely compromised in pulverized solid fuel combustion, in which particle-radiation interaction plays the dominant role in radiation heat transfer due to high particle loading....... Use of conversion-dependent particle emissivity and scattering factor will not only change the particle heating and reaction history, but also alter the radiation intensity and thus temperature profiles in the furnace. For radiation modelling in pulverized fuel combustion, the priority needs...

  16. Parametric Landau damping of space charge modes

    CERN Document Server

    Macridin, Alexandru; Stern, Eric; Amundson, James; Spentzouris, Panagiotis

    2016-01-01

    Landau damping is the mechanism of plasma and beam stabilization; it is caused by energy transfer from collective modes to incoherent motion of resonant particles. Normally this resonance requires the wave frequency in the particle frame to match the resonant particles frequency. Using the Synergia modeling package to study transverse coherent modes of bunched beams with space charge, we have identified a new kind of damping mechanism, parametric Landau damping, driven by the modulation of the wave-particle interaction.

  17. Sources and characteristics of fine particles over the Yellow Sea and Bohai Sea using online single particle aerosol mass spectrometer.

    Science.gov (United States)

    Fu, Huaiyu; Zheng, Mei; Yan, Caiqing; Li, Xiaoying; Gao, Huiwang; Yao, Xiaohong; Guo, Zhigang; Zhang, Yuanhang

    2015-03-01

    Marine aerosols over the East China Seas are heavily polluted by continental sources. During the Chinese Comprehensive Ocean Experiment in November 2012, size and mass spectra of individual atmospheric particles in the size range from 0.2 to 2.0 μm were measured on board by a single particle aerosol mass spectrometer (SPAMS). The average hourly particle number (PN) was around 4560±3240 in the South Yellow Sea (SYS), 2900±3970 in the North Yellow Sea (NYS), and 1700±2220 in the Bohai Sea (BS). PN in NYS and BS varied greatly over 3 orders of magnitude, while that in SYS varied slightly. The size distributions were fitted with two log-normal modes. Accumulation mode dominated in NYS and BS, especially during episodic periods. Coarse mode particles played an important role in SYS. Particles were classified using an adaptive resonance theory based neural network algorithm (ART-2a). Six particle types were identified with secondary-containing, aged sea-salt, soot-like, biomass burning, fresh sea-salt, and lead-containing particles accounting for 32%, 21%, 18%, 16%, 4%, and 3% of total PN, respectively. Aerosols in BS were relatively enriched in particles from anthropogenic sources compared to SYS, probably due to emissions from more developed upwind regions and indicating stronger influence of continental outflow on marine environment. Variation of source types depended mainly on origins of transported air masses. This study examined rapid changes in PN, size distribution and source types of fine particles in marine atmospheres. It also demonstrated the effectiveness of high-time-resolution source apportionment by ART-2a.

  18. Experimental and analytical characterization of the 3D motion of particles in acoustofluidic devices

    DEFF Research Database (Denmark)

    Rossi, M.; Barnkob, Rune; Augustsson, P.;

    2012-01-01

    and to examine the accuracy of analytical force predictions. Polystyrene spheres with diameter of 0.5µm and 5µm were displaced under controlled conditions in a long straight rectangular acoustofluidic microchannel, actuated in its 2-MHz resonance mode, a transverse half-wavelength standing acoustic wave......In this work we present an experimental and analytical study of the acoustophoretic motion of spherical polystyrene particles of different sizes. The primary aim is to understand the three-dimensional extension of the acoustic radiation force and the acoustic streaming-induced drag force....... Astigmatism Particle Tracking Velocimetry (APTV) was used to measure the three-dimensional trajectories, velocities and accelerations of the particles. The experiments show how the acoustic radiation force dominates for the large 5-µm particles, whereas the drag force from the acoustic streaming dominates...

  19. Experimental investigation of coarse particles-water mixture flow in horizontal and inclined pipes

    Directory of Open Access Journals (Sweden)

    Vlasák Pavel

    2014-09-01

    Full Text Available The effect of solid concentration and mixture velocity on the flow behaviour, pressure drops, and concentration distribution of coarse particle-water mixtures in horizontal, vertical, and inclined smooth stainless steel pipes of inner diameter D = 100 mm was experimentally investigated. Graded basalt pebbles were used as solid particles. The study revealed that the coarse-grained particle-water mixtures in the horizontal and inclined pipes were significantly stratified. The solid particles moved principally in a layer close to the pipe invert; however for higher and moderate flow velocities, particle saltation became the dominant mode of particle conveyance. Frictional pressure drops in the horizontal pipe were found to be markedly higher than in the vertical pipe, while the frictional pressure drops in the ascending pipe increased with inclination angle up to about 30°.

  20. Hygroscopic properties of newly formed ultrafine particles at an urban site surrounded by deciduous forest (Sapporo, northern Japan) during the summer of 2011

    Science.gov (United States)

    Jung, J.; Kawamura, K.

    2014-07-01

    To investigate the hygroscopic properties of ultrafine particles during new particle formation events, the hygroscopic growth factors of size-segregated atmospheric particles were measured at an urban site in Sapporo, northern Japan, during the summer of 2011. The hygroscopic growth factor at 85 % relative humidity [g(85%)] of freshly formed nucleation mode particles was 1.11 to 1.28 (average: 1.16 ± 0.06) at a dry particle diameter (Dp) centered on 20 nm, which is equivalent to 1.17 to 1.35 (1.23 ± 0.06) at a dry Dp centered on 100 nm after considering the Kelvin effect. These values are comparable with those of secondary organic aerosols, suggesting that low-volatility organic vapors are important to the burst of nucleation mode particles. The equivalent g(85%) at a dry Dp of 100 nm for nucleated particles that have grown to Aitken mode sizes (1.24 to 1.34; average: 1.30 ± 0.04) were slightly higher than those of newly formed nucleation mode particles, suggesting that the growth of freshly formed nucleation mode particles to the Aitken mode size can be subjected to condensation of not only low-volatility organic vapors, but also water-soluble inorganic species. Based on this result, and previous measurement of radiocarbon in aerosols, we suggest that the burst of nucleation mode particles and their subsequent growth were highly affected by biogenic organic emissions at this measurement site, which is surrounded by deciduous forest. Gradual increases in mode diameter after the burst of nucleation mode particles were observed under southerly wind conditions, with a dominant contribution of intermediately hygroscopic particles. However, sharp increases in mode diameter were observed when the wind direction shifted to northwesterly or northeasterly, with a sharp increase in the highly hygroscopic particle fraction of the Aitken mode particles, indicating that the hygroscopic growth factor of newly formed particles is perturbed by the local winds that deliver

  1. Rings dominate western Gulf

    Science.gov (United States)

    Vidal L., Francisco V.; Vidal L., Victor M. V.; Molero, José María Pérez

    Surface and deep circulation of the central and western Gulf of Mexico is controlled by interactions of rings of water pinched from the gulf's Loop Current. The discovery was made by Mexican oceanographers who are preparing a full-color, 8-volume oceanographic atlas of the gulf.Anticyclonic warm-core rings pinch off the Loop Current at a rate of about one to two per year, the scientists of the Grupo de Estudios Oceanográficos of the Instituto de Investigaciones Eléctricas (GEO-IIE) found. The rings migrate west until they collide with the continental shelf break of the western gulf, almost always between 22° and 23°N latitude. On their westward travel they transfer angular momentum and vorticity to the surrounding water, generating cyclonic circulations and vortex pairs that completely dominate the entire surface and deep circulation of the central and western gulf.

  2. Dynamic Mode Decomposition for Large and Streaming Datasets

    CERN Document Server

    Hemati, Maziar S; Rowley, Clarence W

    2014-01-01

    We formulate a low-storage method for performing dynamic mode decomposition that can be updated inexpensively as new data become available; this formulation allows dynamical information to be extracted from large datasets and data streams. We present two algorithms: the first is mathematically equivalent to a standard "batch-processed" formulation; the second introduces a compression step that maintains computational efficiency, while enhancing the ability to isolate pertinent dynamical information from noisy measurements. Both algorithms reliably capture dominant fluid dynamic behaviors, as demonstrated on cylinder wake data collected from both direct numerical simulations and particle image velocimetry experiments

  3. Distribution network service restoration using a multi-objective binary particle swarm optimization based on E-dominance%基于E占优的多目标二进制粒子群算法求解配电网故障恢复

    Institute of Scientific and Technical Information of China (English)

    姚玉海; 王增平; 郭昆亚; 金鹏

    2014-01-01

    针对基于Pareto占优机制和拥挤距离的经典多目标智能算法在迭代过程中没有考虑决策者的偏好知识,从而影响了算法收敛性的问题,提出了一种基于E占优的多目标二进制粒子群算法求解配电网故障恢复。通过采用改进原点距离的E占优机制,可以将决策者的偏好知识有效地融入到故障恢复方案的评价过程中。在算法迭代过程中,采用轮盘赌策略更新群体极值,采用方案的综合值对外部档案进行维护,使得决策者的偏好知识可以有效地指导下一代种群的产生。最后,通过算例验证了所提算法的可行性和有效性,并且该方法比基于Pareto占优机制和拥挤距离的多目标智能算法拥有更好的收敛性能,得到的最优前沿数量更少,质量更高。%The classic multi-objective evolutionary algorithm based on Pareto dominance criteria and crowding distance sorting method does not consider the preference of decision maker in the iterative process, which leads to the decline of convergence performance. For the problem, this paper proposes a multi-objective binary particle swarm optimization based on E-dominance to solve distribution network service restoration. By adopting E-dominance strategy of improving the origin distance, it can integrate the preference of decision makers into the evaluation process. This paper adopts roulette strategy to update the global best solution and integrated value to maintenance the external files, which can effectively guide the next generation of particle with preference of decision makers during iterative process. Finally, an example shows that the approach has better convergence performance, less quantity and better quality on solution than the classic multi-objective algorithm based on Pareto dominance criteria and crowding distance.

  4. Modes in the size distributions and neutralization extent of fog-processed ammonium salt aerosols observed at Canadian rural locations

    Directory of Open Access Journals (Sweden)

    X. H. Yao

    2012-02-01

    Full Text Available Among the 192 samples of size-segregated water-soluble inorganic ions collected using a Micro-Orifice Uniform Deposit Impactor (MOUDI at eight rural locations in Canada, ten samples were identified to have gone through fog processing. The supermicron particle modes of ammonium salt aerosols were found to be the fingerprint of fog processed aerosols. However, the patterns and the sizes of the supermicron modes varied with ambient temperature (T and particle acidity and also differed between inland and coastal locations. Under T > 0 °C condition, fog-processed ammonium salt aerosols were completely neutralized and had a dominant mode at 1–2 μm and a minor mode at 5–10 μm if particles were in neutral condition, and ammonium sulfate was incompletely neutralized and only had a 1–2 μm mode if particles were in acidic conditions. Under T < 0 °C at the coastal site, fog-processed aerosols exhibited a bi-modal size distribution with a dominant mode of incompletely-neutralized ammonium sulfate at about 3 μm and a minor mode of completely-neutralized ammonium sulfate at 8–9 μm. Under T < 0 °C condition at the inland sites, fog-processed ammonium salt aerosols were sometimes completely neutralized and sometimes incompletely neutralized, and the size of the supermicron mode was in the range from 1 to 5 μm. Overall, fog-processed ammonium salt aerosols under T < 0 °C condition were generally distributed at larger size (e.g., 2–5 μm than those under T > 0 °C condition (e.g., 1–2 μm.

  5. Asymmetric Dark Matter in the shear-dominated universe

    Science.gov (United States)

    Iminniyaz, Hoernisa

    2017-02-01

    We explore the relic abundance of asymmetric Dark Matter in shear-dominated universe in which it is assumed the universe is expanded anisotropically. The modified expansion rate leaves its imprint on the relic density of asymmetric Dark Matter particles if the asymmetric Dark Matter particles are decoupled in shear dominated era. We found the relic abundances for particle and anti-particle are increased. The particle and anti-particle abundances are almost in the same amount for the larger value of the shear factor xe which makes the indirect detection possible for asymmetric Dark Matter. We use the present day Dark Matter density from the observation to find the constraints on the parameter space in this model.

  6. Observations of urban airborne particle number concentrations during rush-hour conditions: analysis of the number based size distributions and modal parameters.

    Science.gov (United States)

    Lingard, Justin J N; Agus, Emily L; Young, David T; Andrews, Gordon E; Tomlin, Alison S

    2006-12-01

    A summertime study of the number concentration and the size distribution of combustion derived nanometre sized particles (termed nanoparticles) from diesel and spark-ignition (SI) engine emissions were made under rush-hour and free-flow traffic conditions at an urban roadside location in Leeds, UK in July 2003. The measured total particle number concentrations (N(TOTAL)) were of the order 1.8 x 10(4) to 3.4 x 10(4) cm(-3), and tended to follow the diurnal traffic flow patterns. The N(TOTAL) was dominated by particles particle number. By use of a log-normal fitting procedure, the modal parameters of the number based particle size distribution of urban airborne particulates were derived from the roadside measurements. Four component modes were identified. Two nucleation modes were found, with a smaller, more minor, mode composed principally of sub-11 nm particles, believed to be derived from particles formed from the nucleation of gaseous species in the atmosphere. A second mode, much larger in terms of number, was composed of particles within the size range of 10-20 nm. This second mode was believed to be principally derived from the condensation of the unburned fuel and lube oil (the solvent organic fraction or SOF) as it cooled on leaving the engine exhaust. Third and fourth modes were noted within the size ranges of 28-65 nm and 100-160 nm, respectively. The third mode was believed to be representative of internally mixed Aitken mode particles composed of a soot/ash core with an adsorbed layer of readily volatilisable material. The fourth mode was believed to be composed of chemically aged, secondary particles. The larger nucleation and Aitken modes accounted for between 80-90% of the measured N(TOTAL), and the particles in these modes were believed to be derived from SI and diesel engine emissions. The overall size distribution, particularly in modes II-IV, was observed to be strongly related to the number of primary particle emissions, with larger count median

  7. 面对形成中的支配性文化及其生产方式——“理论之后”的当代中国文化批评%Responding to the Formation of Dominant Culture and its Production Mode : Contemporary Chinese Cultural Criticism in the Era of After - Theory

    Institute of Scientific and Technical Information of China (English)

    曾军

    2012-01-01

    “理论之后”作为一种理论背景,并非中国文化批评走向困境的标志,而是真正走向“文化自觉”的象征。“理论之后”,西方文化理论并非毫无建树,而是正在发生转型;中国的文化批评实践需要重新确立本土性的研究对象、问题意识和研究方法,应在这林林总总的文化现象、思潮、冲突与激荡中形成对当代中国文化发展特征的某种认识,或者更准确地说,应致力于“形成中的支配性文化”的参与性研究,“主流大众文化”可以成为对之的一种命名;在这一以媒介技术、商品消费为取向的文化生产大潮中,处于支配性地位的便不再只是纯文学、高雅艺术和精英文化了,而是由权力、资本、技术以及相应的文化趣味相交织而形成的通俗文化、大众文化以及相应的文化产业形态。文化批评需要在文化产业领域进行强有力的批判性质疑和建设性参与,从而真正介入并影响支配性文化的形成。%In the era of what Terry Eagleton terms as "After - Theory," cultural criticism practice in China needs to re - problematize its research, redefine its object with a focus on the local culture and sharpen its research methodology in response to current theoretical transformations so as to delineate some traits in the development of contemporary cultural development out of various cultural phenomena, currents and conflicts. The paper claims that the cultural criticism should engage in participatory research of "the dominant culture in formation," and that this dominant euhure can be named as "mainstream mass culture. " The current dominant cultural production mode is increasingly oriented toward media technology and consumption, with the dominance of pure literature, high - brow arts and elite culture on the wane, and it is a state of cultural industry infused with power, capital, technology and the resultant cultural

  8. Onset dominance in lateralization.

    Science.gov (United States)

    Freyman, R L; Zurek, P M; Balakrishnan, U; Chiang, Y C

    1997-03-01

    Saberi and Perrott [Acustica 81, 272-275 (1995)] found that the in-head lateralization of a relatively long-duration pulse train could be controlled by the interaural delay of the single pulse pair that occurs at onset. The present study examined this further, using an acoustic pointer measure of lateralization, with stimulus manipulations designed to determine conditions under which lateralization was consistent with the interaural onset delay. The present stimuli were wideband pulse trains, noise-burst trains, and inharmonic complexes, 250 ms in duration, chosen for the ease with which interaural delays and correlations of select temporal segments of the stimulus could be manipulated. The stimulus factors studied were the periodicity of the ongoing part of the signal as well as the multiplicity and ambiguity of interaural delays. The results, in general, showed that the interaural onset delay controlled lateralization when the steady state binaural cues were relatively weak, either because the spectral components were only sparsely distributed across frequency or because the interaural time delays were ambiguous. Onset dominance can be disrupted by sudden stimulus changes within the train, and several examples of such changes are described. Individual subjects showed strong left-right asymmetries in onset effectiveness. The results have implications for understanding how onset and ongoing interaural delay cues contribute to the location estimates formed by the binaural auditory system.

  9. Particle Pollution

    Science.gov (United States)

    ... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...

  10. The dominance of norm

    Directory of Open Access Journals (Sweden)

    Edward L. Rubin

    2017-06-01

    Full Text Available Objective to revisit the debate about rational choice theory from the legal cultural and historical perspectives. Methods dialectic approach to the cognition of social phenomena allowing to analyze them in their historical development and functioning in the context of the integrity of subjective and objective factors this determines the choice of the research methods systemicstructural formallegal and comparative. Results The first part of this chapter will explain the way in which people in societies different from our own were subject to other motivations in situations where selfinterest would tend to dominate in our society. The reasoning is based on three examples one drawn from the history of Ancient Rome one from the High Middle Ages of the European society and one from a contemporary nonWestern culture. The second part of the chapter analyzes the reason why material selfinterest maximizing became a dominant motivation in the modern Western society. The works on historical sociology attribute this development to Calvinism but this hypothesis suffers from some serious defects. In the article we prove that the modern sensibility resulted from much longeracting trends specifically secularization urbanization and commercialization. The final section of the chapter explores the relationship between the Westrsquos prevailing norm of selfinterest maximization and the particular norms that have been discussed in microeconomic theory. It argues that some of these norms are internal to the prevailing one and are thus explicable in terms of material selfinterest but that others reflect additional norms in the general society that exist alongside and sometimes in competition with the prevailing norm of selfinterest maximization. The historicallybased view that selfinterest maximizing is a prevailing norm rather than a human universal allows these other norms to be acknowledged in a plausible and realistic manner rather than being explained away by a

  11. Organic particle types by single-particle measurements using a time-of-flight aerosol mass spectrometer coupled with a light scattering module

    Directory of Open Access Journals (Sweden)

    S. Liu

    2013-02-01

    Full Text Available Chemical and physical properties of individual ambient aerosol particles can vary greatly, so measuring the chemical composition at the single-particle level is essential for understanding atmospheric sources and transformations. Here we describe 46 days of single-particle measurements of atmospheric particles using a time-of-flight aerosol mass spectrometer coupled with a light scattering module (LS-ToF-AMS. The light scattering module optically detects particles larger than 180 nm vacuum aerodynamic diameter (130 nm geometric diameter before they arrive at the chemical mass spectrometer and then triggers the saving of single-particle mass spectra. 271 641 particles were detected and sampled during 237 h of sampling in single-particle mode. By comparing timing of the predicted chemical ion signals from the light scattering measurement with the measured chemical ion signals by the mass spectrometer for each particle, particle types were classified and their number fractions determined as follows: prompt vaporization (46%, delayed vaporization (6%, and null (48%, where null was operationally defined as less than 6 ions per particle. Prompt and delayed vaporization particles with sufficient chemical information (i.e., more than 40 ions per particle were clustered based on similarity of organic mass spectra (using k-means algorithm to result in three major clusters: highly oxidized particles (dominated by m/z 44, relatively less oxidized particles (dominated by m/z 43, and particles associated with fresh urban emissions. Each of the three organic clusters had limited chemical properties of other clusters, suggesting that all of the sampled organic particle types were internally mixed to some degree; however, the internal mixing was never uniform and distinct particle types existed throughout the study. Furthermore, the single-particle mass spectra and time series of these clusters agreed well with mass-based components

  12. On Dominator Colorings in Graphs

    Indian Academy of Sciences (India)

    S Arumugam; Jay Bagga; K Raja Chandrasekar

    2012-11-01

    A dominator coloring of a graph is a proper coloring of in which every vertex dominates every vertex of at least one color class. The minimum number of colors required for a dominator coloring of is called the dominator chromatic number of and is denoted by $ d(G)$. In this paper we present several results on graphs with $ d(G)=(G)$ and $ d(G)=(G)$ where $(G)$ and $(G)$ denote respectively the chromatic number and the domination number of a graph . We also prove that if $(G)$ is the Mycielskian of , then $ d(G)+1≤ d((G))≤ d(G)+2$.

  13. Constraining primordial vector mode from B-mode polarization

    Energy Technology Data Exchange (ETDEWEB)

    Saga, Shohei; Ichiki, Kiyotomo [Department of Physics and Astrophysics, Nagoya University, Aichi 464-8602 (Japan); Shiraishi, Maresuke, E-mail: saga.shohei@nagoya-u.jp, E-mail: maresuke.shiraishi@pd.infn.it, E-mail: ichiki@a.phys.nagoya-u.ac.jp [Dipartimento di Fisica e Astronomia ' ' G. Galilei' ' , Università degli Studi di Padova, via Marzolo 8, I-35131, Padova (Italy)

    2014-10-01

    The B-mode polarization spectrum of the Cosmic Microwave Background (CMB) may be the smoking gun of not only the primordial tensor mode but also of the primordial vector mode. If there exist nonzero vector-mode metric perturbations in the early Universe, they are known to be supported by anisotropic stress fluctuations of free-streaming particles such as neutrinos, and to create characteristic signatures on both the CMB temperature, E-mode, and B-mode polarization anisotropies. We place constraints on the properties of the primordial vector mode characterized by the vector-to-scalar ratio r{sub v} and the spectral index n{sub v} of the vector-shear power spectrum, from the Planck and BICEP2 B-mode data. We find that, for scale-invariant initial spectra, the ΛCDM model including the vector mode fits the data better than the model including the tensor mode. The difference in χ{sup 2} between the vector and tensor models is Δχ{sup 2} = 3.294, because, on large scales the vector mode generates smaller temperature fluctuations than the tensor mode, which is preferred for the data. In contrast, the tensor mode can fit the data set equally well if we allow a significantly blue-tilted spectrum. We find that the best-fitting tensor mode has a large blue tilt and leads to an indistinct reionization bump on larger angular scales. The slightly red-tilted vector mode supported by the current data set can also create O(10{sup -22})-Gauss magnetic fields at cosmological recombination. Our constraints should motivate research that considers models of the early Universe that involve the vector mode.

  14. Dominant optic atrophy

    Directory of Open Access Journals (Sweden)

    Lenaers Guy

    2012-07-01

    Full Text Available Abstract Definition of the disease Dominant Optic Atrophy (DOA is a neuro-ophthalmic condition characterized by a bilateral degeneration of the optic nerves, causing insidious visual loss, typically starting during the first decade of life. The disease affects primary the retinal ganglion cells (RGC and their axons forming the optic nerve, which transfer the visual information from the photoreceptors to the lateral geniculus in the brain. Epidemiology The prevalence of the disease varies from 1/10000 in Denmark due to a founder effect, to 1/30000 in the rest of the world. Clinical description DOA patients usually suffer of moderate visual loss, associated with central or paracentral visual field deficits and color vision defects. The severity of the disease is highly variable, the visual acuity ranging from normal to legal blindness. The ophthalmic examination discloses on fundoscopy isolated optic disc pallor or atrophy, related to the RGC death. About 20% of DOA patients harbour extraocular multi-systemic features, including neurosensory hearing loss, or less commonly chronic progressive external ophthalmoplegia, myopathy, peripheral neuropathy, multiple sclerosis-like illness, spastic paraplegia or cataracts. Aetiology Two genes (OPA1, OPA3 encoding inner mitochondrial membrane proteins and three loci (OPA4, OPA5, OPA8 are currently known for DOA. Additional loci and genes (OPA2, OPA6 and OPA7 are responsible for X-linked or recessive optic atrophy. All OPA genes yet identified encode mitochondrial proteins embedded in the inner membrane and ubiquitously expressed, as are the proteins mutated in the Leber Hereditary Optic Neuropathy. OPA1 mutations affect mitochondrial fusion, energy metabolism, control of apoptosis, calcium clearance and maintenance of mitochondrial genome integrity. OPA3 mutations only affect the energy metabolism and the control of apoptosis. Diagnosis Patients are usually diagnosed during their early childhood, because of

  15. Physics basis of Multi-Mode anomalous transport module

    Energy Technology Data Exchange (ETDEWEB)

    Rafiq, T.; Kritz, A. H.; Luo, L. [Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Weiland, J. [Departments of Applied Physics, Chalmers University of Technology and Euratom-VR Assoc., S41296 Gothenburg (Sweden); Pankin, A. Y. [Tech-X Corporation, Boulder, Colorado (United States)

    2013-03-15

    The derivation of Multi-Mode anomalous transport module version 8.1 (MMM8.1) is presented. The MMM8.1 module is advanced, relative to MMM7.1, by the inclusion of peeling modes, dependence of turbulence correlation length on flow shear, electromagnetic effects in the toroidal momentum diffusivity, and the option to compute poloidal momentum diffusivity. The MMM8.1 model includes a model for ion temperature gradient, trapped electron, kinetic ballooning, peeling, collisionless and collision dominated magnetohydrodynamics modes as well as model for electron temperature gradient modes, and a model for drift resistive inertial ballooning modes. In the derivation of the MMM8.1 module, effects of collisions, fast ion and impurity dilution, non-circular flux surfaces, finite beta, and Shafranov shift are included. The MMM8.1 is used to compute thermal, particle, toroidal, and poloidal angular momentum transports. The fluid approach which underlies the derivation of MMM8.1 is expected to reliably predict, on an energy transport time scale, the evolution of temperature, density, and momentum profiles in plasma discharges for a wide range of plasma conditions.

  16. Role of density gradient driven trapped electron mode turbulence in the H-mode inner core with electron heating

    Science.gov (United States)

    Ernst, D. R.; Burrell, K. H.; Guttenfelder, W.; Rhodes, T. L.; Dimits, A. M.; Bravenec, R.; Grierson, B. A.; Holland, C.; Lohr, J.; Marinoni, A.; McKee, G. R.; Petty, C. C.; Rost, J. C.; Schmitz, L.; Wang, G.; Zemedkun, S.; Zeng, L.

    2016-05-01

    A series of DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] low torque quiescent H-mode experiments show that density gradient driven trapped electron mode (DGTEM) turbulence dominates the inner core of H-mode plasmas during strong electron cyclotron heating (ECH). Adding 3.4 MW ECH doubles Te/Ti from 0.5 to 1.0, which halves the linear DGTEM critical density gradient, locally reducing density peaking, while transport in all channels displays extreme stiffness in the density gradient. This suggests that fusion α-heating may degrade inner core confinement in H-mode plasmas with moderate density peaking and low collisionality, with equal electron and ion temperatures, key conditions expected in burning plasmas. Gyrokinetic simulations using GYRO [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] (and GENE [Jenko et al., Phys. Plasmas 7, 1904 (2000)]) closely match not only particle, energy, and momentum fluxes but also density fluctuation spectra from Doppler backscattering (DBS), with and without ECH. Inner core DBS density fluctuations display discrete frequencies with adjacent toroidal mode numbers, which we identify as DGTEMs. GS2 [Dorland et al., Phys. Rev. Lett. 85, 5579 (2000)] predictions show the DGTEM can be suppressed, to avoid degradation with electron heating, by broadening the current density profile to attain q0>qmin>1 .

  17. Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2007-05-01

    Full Text Available Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS were carried out in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area – 2006 campaign (MCMA-2006 between 7–27 March, 2006. Biomass and organic carbon (OC particle types were found to dominate the accumulation mode both day and night. The concentrations of both organic carbon and biomass particles were roughly equal early in the morning, but biomass became the largest contributor to the accumulation mode mass from the late morning until early evening. The diurnal pattern can be attributed to aging and/or a change in meteorology. Fresh elemental carbon (EC particles were observed during rush hour. The majority of the EC particles were mixed with nitrate, sulfate, organic carbon and potassium. Submicron particles from industrial sources in the northeast were composed of an internal mixture of Pb, Zn, EC and Cl and peaked early in the morning. A unique nitrogen-containing organic (NOC particle type was observed, and is hypothesized to be from industrial emissions based on the temporal profile and back trajectory analysis. This study provides unique insights into the real-time changes in single particle mixing state as a function of size and time for aerosols in Mexico City. These new findings indicate that biomass burning and industrial operations make significant contributions to particles in Mexico City. These sources have received relatively little attention in previous intensive field campaigns.

  18. Effects of microstructure and crystallography on crack path and intrinsic resistance to shear-mode fatigue crack growth

    Directory of Open Access Journals (Sweden)

    J. Pokluda

    2015-10-01

    Full Text Available The paper focuses on the effective resistance and the near-threshold growth mechanisms in the ferritic-pearlitic and the pure pearlitic steel. The influence of microstructure on the shear-mode fatigue crack growth is divided here into two factors: the crystal lattice type and the presence of different phases. Experiments were done on ferritic-pearlitic steel and pearlitic steel using three different specimens, for which the effective mode II and mode III threshold values were measured and fracture surfaces were reconstructed in three dimensions using stereophotogrammetry in scanning electron microscope. The ferritic-pearlitic and pearlitic steels showed a much different behaviour of modes II and III cracks than that of the ARMCO iron. Both the deflection angle and the mode II threshold were much higher and comparable to the austenitic steel. Mechanism of shear-mode crack behaviour in the ARMCO iron, titanium and nickel were described by the model of emission of dislocations from the crack tip under a dominant mode II loading. In other tested materials the cracks propagated under a dominance of the local mode I. In the ferritic-pearlitic and pearlitic steels, the reason for such behaviour was the presence of the secondary-phase particles (cementite lamellas, unlike in the previously austenitic steel, where the fcc structure and the low stacking fault energy were the main factors. A criterion for mode I deflection from the mode II crack-tip loading, which uses values of the effective mode I and mode II thresholds, was in agreement with fractographical observations.

  19. Particle segregation during explosive dispersal of binary particle mixtures

    Science.gov (United States)

    Frost, David L.; Loiseau, Jason; Marr, Bradley J.; Goroshin, Samuel

    2017-01-01

    The explosive dispersal of a layer of solid particles surrounding a spherical high explosive charge generates a turbulent, multiphase flow. The shock-compacted particle layer typically fractures into discrete fragments which move radially outwards on ballistic trajectories. The fragments shed particles in their wakes forming jet-like structures. The tendency to form jets depends on the mass-ratio of the particles to explosive and the type of particles. Brittle or soft, ductile particles are more susceptible to forming jets during compaction and dispersal, whereas particles that are comprised of material with moderate hardness, high compressive strength and high toughness are much less prone to forming jets. Experiments have been carried out to determine the degree of particle segregation that occurs during the explosive dispersal of a uniform, binary mixture containing both "jetting" (silicon carbide) and "non-jetting" (steel) particles with various mass fractions of each particle type. During the dispersal of mixtures that contain predominantly non-jetting (steel) particles, the steel particles form a stable layer whereas the jetting (silicon carbide) particles rapidly segregate and form jets which are confined within the shell of steel particles. As the fraction of silicon carbide particles increases, the jet structures dominate the particle motion and the steel particles are entrained into the jet structures.

  20. Brain Dominance & Self-Actualization.

    Science.gov (United States)

    Bernhoft, Franklin O.

    Numerous areas associated with brain dominance have been researched since Bogen and Sperry's work with split-brain patients in the 1960s, but only slight attention has been given to the connection between brain dominance and personality. No study appears in the literature seeking to understand optimal mental health as defined by Maslow's…

  1. Distributional dominance with dirty data

    OpenAIRE

    2001-01-01

    Distributional dominance criteria are commonly applied to draw welfare in- ferences about comparisons, but conclusions drawn from empirical imple- mentations of dominance criteria may be inßuenced by data contamination. We examine a non-parametric approach to reÞning Lorenz-type comparisons and apply the technique to two important examples from the LIS data-base.

  2. Dominant Leadership Style in Schools

    Science.gov (United States)

    Rajbhandari, Mani Man Singh

    2006-01-01

    The dominant leadership style is defined by the situation and the kind of organizational environment and climate. This, however, does not sufficiently define the leadership qualities in school organizations. There are other factors which also determine the dominant leadership style, which are the traits and style, teachers commitments, pass out…

  3. Seasonal variation of atmospheric particle number concentrations, new particle formation and atmospheric oxidation capacity at the high Arctic site Villum Research Station, Station Nord

    Science.gov (United States)

    Nguyen, Quynh T.; Glasius, Marianne; Sørensen, Lise L.; Jensen, Bjarne; Skov, Henrik; Birmili, Wolfram; Wiedensohler, Alfred; Kristensson, Adam; Nøjgaard, Jacob K.; Massling, Andreas

    2016-09-01

    This work presents an analysis of the physical properties of sub-micrometer aerosol particles measured at the high Arctic site Villum Research Station, Station Nord (VRS), northeast Greenland, between July 2010 and February 2013. The study focuses on particle number concentrations, particle number size distributions and the occurrence of new particle formation (NPF) events and their seasonality in the high Arctic, where observations and characterization of such aerosol particle properties and corresponding events are rare and understanding of related processes is lacking.A clear accumulation mode was observed during the darker months from October until mid-May, which became considerably more pronounced during the prominent Arctic haze months from March to mid-May. In contrast, nucleation- and Aitken-mode particles were predominantly observed during the summer months. Analysis of wind direction and wind speed indicated possible contributions of marine sources from the easterly side of the station to the observed summertime particle number concentrations, while southwesterly to westerly winds dominated during the darker months. NPF events lasting from hours to days were mostly observed from June until August, with fewer events observed during the months with less sunlight, i.e., March, April, September and October. The results tend to indicate that ozone (O3) might be weakly anti-correlated with particle number concentrations of the nucleation-mode range (10-30 nm) in almost half of the NPF events, while no positive correlation was observed. Calculations of air mass back trajectories using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model for the NPF event days suggested that the onset or interruption of events could possibly be explained by changes in air mass origin. A map of event occurrence probability was computed, indicating that southerly air masses from over the Greenland Sea were more likely linked to those events.

  4. Eternal Domination: Criticality and Reachability

    Directory of Open Access Journals (Sweden)

    Klostermeyer William F.

    2017-02-01

    Full Text Available We show that for every minimum eternal dominating set, D, of a graph G and every vertex v ∈ D, there is a sequence of attacks at the vertices of G which can be defended in such a way that an eternal dominating set not containing v is reached. The study of the stronger assertion that such a set can be reached after a single attack is defended leads to the study of graphs which are critical in the sense that deleting any vertex reduces the eternal domination number. Examples of these graphs and tight bounds on connectivity, edge-connectivity and diameter are given. It is also shown that there exist graphs in which deletion of any edge increases the eternal domination number, and graphs in which addition of any edge decreases the eternal domination number.

  5. Concentrations of ultrafine particles at a highway toll collection booth and exposure implications for toll collectors.

    Science.gov (United States)

    Cheng, Yu-Hsiang; Huang, Cheng-Hsiung; Huang, Hsiao-Lin; Tsai, Chuen-Jinn

    2010-12-15

    Research regarding the magnitude of ultrafine particle levels at highway toll stations is limited. This study measured ambient concentrations of ultrafine particles at a highway toll station from October 30 to November 1 and November 5 to November 6, 2008. A scanning mobility particle sizer was used to measure ultrafine particle concentrations at a ticket/cash tollbooth. Levels of hourly average ultrafine particles at the tollbooth were about 3-6 times higher than those in urban backgrounds, indicating that a considerable amount of ultrafine particles are exhausted from passing vehicles. A bi-modal size distribution pattern with a dominant mode at about particle reactions in fresh fumes emitted directly from vehicles. The influences of traffic volume, wind speed, and relative humidity on ultrafine particle concentrations were also determined. High ambient concentrations of ultrafine particles existed under low wind speed, low relative humidity, and high traffic volume. Although different factors account for high ambient concentrations of ultrafine particles at the tollbooth, measurements indicate that toll collectors who work close to traffic emission sources have a high exposure risk.

  6. Mode-by-mode hydrodynamics: Ideas and concepts

    Energy Technology Data Exchange (ETDEWEB)

    Floerchinger, Stefan

    2014-06-15

    The main ideas, technical concepts and perspectives for a mode resolved description of the hydrodynamical regime of relativistic heavy ion collisions are discussed. A background-fluctuation splitting and a Bessel–Fourier expansion for the fluctuating part of the hydrodynamical fields allows for a complete characterization of initial conditions, the fluid dynamical propagation of single modes, the study of interaction effects between modes, the determination of the associated particle spectra and the generalization of the whole program to event-by-event correlations and probability distributions.

  7. The strange physics of low frequency mirror mode turbulence in the high temperature plasma of the magnetosheath

    Directory of Open Access Journals (Sweden)

    R. A. Treumann

    2004-01-01

    Full Text Available Mirror mode turbulence is the lowest frequency perpendicular magnetic excitation in magnetized plasma proposed already about half a century ago by Rudakov and Sagdeev (1958 and Chandrasekhar et al. (1958 from fluid theory. Its experimental verification required a relatively long time. It was early recognized that mirror modes for being excited require a transverse pressure (or temperature anisotropy. In principle mirror modes are some version of slow mode waves. Fluid theory, however, does not give a correct physical picture of the mirror mode. The linear infinitesimally small amplitude physics is described correctly only by including the full kinetic theory and is modified by existing spatial gradients of the plasma parameters which attribute a small finite frequency to the mode. In addition, the mode is propagating only very slowly in plasma such that convective transport is the main cause of flow in it. As the lowest frequency mode it can be expected that mirror modes serve as one of the dominant energy inputs into plasma. This is however true only when the mode grows to large amplitude leaving the linear stage. At such low frequencies, on the other hand, quasilinear theory does not apply as a valid saturation mechanism. Probably the dominant processes are related to the generation of gradients in the plasma which serve as the cause of drift modes thus transferring energy to shorter wavelength propagating waves of higher nonzero frequency. This kind of theory has not yet been developed as it has not yet been understood why mirror modes in spite of their slow growth rate usually are of very large amplitudes indeed of the order of |B/B0|2~O(1. It is thus highly reasonable to assume that mirror modes are instrumental for the development of stationary turbulence in high temperature plasma. Moreover, since the magnetic field in mirror turbulence forms extended though slightly oblique magnetic bottles, low parallel energy particles can be trapped

  8. New Edge Coherent Mode Providing Continuous Transport in Long-Pulse H-mode Plasmas

    Science.gov (United States)

    Wang, H. Q.; Xu, G. S.; Wan, B. N.; Ding, S. Y.; Guo, H. Y.; Shao, L. M.; Liu, S. C.; Xu, X. Q.; Wang, E.; Yan, N.; Naulin, V.; Nielsen, A. H.; Rasmussen, J. Juul; Candy, J.; Bravenec, R.; Sun, Y. W.; Shi, T. H.; Liang, Y. F.; Chen, R.; Zhang, W.; Wang, L.; Chen, L.; Zhao, N.; Li, Y. L.; Liu, Y. L.; Hu, G. H.; Gong, X. Z.

    2014-05-01

    An electrostatic coherent mode near the electron diamagnetic frequency (20-90 kHz) is observed in the steep-gradient pedestal region of long pulse H-mode plasmas in the Experimental Advanced Superconducting Tokamak, using a newly developed dual gas-puff-imaging system and diamond-coated reciprocating probes. The mode propagates in the electron diamagnetic direction in the plasma frame with poloidal wavelength of ˜8 cm. The mode drives a significant outflow of particles and heat as measured directly with the probes, thus greatly facilitating long pulse H-mode sustainment. This mode shows the nature of dissipative trapped electron mode, as evidenced by gyrokinetic turbulence simulations.

  9. Size-resolved particle number emission patterns under real-world driving conditions using positive matrix factorization.

    Science.gov (United States)

    Domínguez-Sáez, Aida; Viana, Mar; Barrios, Carmen C; Rubio, Jose R; Amato, Fulvio; Pujadas, Manuel; Querol, Xavier

    2012-10-16

    A novel on-board system was tested to characterize size-resolved particle number emission patterns under real-world driving conditions, running in a EURO4 diesel vehicle and in a typical urban circuit in Madrid (Spain). Emission profiles were determined as a function of driving conditions. Source apportionment by Positive Matrix Factorization (PMF) was carried out to interpret the real-world driving conditions. Three emission patterns were identified: (F1) cruise conditions, with medium-high speeds, contributing in this circuit with 60% of total particle number and a particle size distribution dominated by particles >52 nm and around 60 nm; (F2) transient conditions, stop-and-go conditions at medium-high speed, contributing with 25% of the particle number and mainly emitting particles in the nucleation mode; and (F3) creep-idle conditions, representing traffic congestion and frequent idling periods, contributing with 14% to the total particle number and with particles in the nucleation mode (conditions. Differences between real-world emission patterns and regulatory cycles (NEDC) are also presented, which evidence that detecting particle number emissions real-world driving conditions.

  10. Source appointment of fine particle number and volume concentration during severe haze pollution in Beijing in January 2013.

    Science.gov (United States)

    Liu, Zirui; Wang, Yuesi; Hu, Bo; Ji, Dongsheng; Zhang, Junke; Wu, Fangkun; Wan, Xin; Wang, Yonghong

    2016-04-01

    Extreme haze episodes repeatedly shrouded Beijing during the winter of 2012-2013, causing major environmental and health problems. To better understand these extreme events, particle number size distribution (PNSD) and particle chemical composition (PCC) data collected in an intensive winter campaign in an urban site of Beijing were used to investigate the sources of ambient fine particles. Positive matrix factorization (PMF) analysis resolved a total of eight factors: two traffic factors, combustion factors, secondary aerosol, two accumulation mode aerosol factors, road dust, and long-range transported (LRT) dust. Traffic emissions (54%) and combustion aerosol (27%) were found to be the most important sources for particle number concentration, whereas combustion aerosol (33%) and accumulation mode aerosol (37%) dominated particle volume concentrations. Chemical compositions and sources of fine particles changed dynamically in the haze episodes. An enhanced role of secondary inorganic species was observed in the formation of haze pollution. Regional transport played an important role for high particles, contribution of which was on average up to 24-49% during the haze episodes. Secondary aerosols from urban background presented the largest contributions (45%) for the rapid increase of fine particles in the severest haze episode. In addition, the invasion of LRT dust aerosols further elevated the fine particles during the extreme haze episode. Our results showed a clear impact of regional transport on the local air pollution, suggesting the importance of regional-scale emission control measures in the local air quality management of Beijing.

  11. The impact of heating the breakdown bubble on the global mode of a swirling jet: Experiments and linear stability analysis

    CERN Document Server

    Rukes, Lothar; Paschereit, Oliver; Oberleithner, Kilian

    2016-01-01

    This study investigates the dynamics of non-isothermal swirling jets undergoing vortex breakdown, with an emphasis on helical coherent structures. It is proposed that the dominant helical coherent structure can be suppressed by heating the recirculation bubble. This proposition is assessed with Stereo Particle Image Velocimetry (PIV) measurements of the breakdown region of isothermal and heated swirling jets. The coherent kinetic energy of the dominant helical structure was derived from PIV snapshots via Proper Orthogonal Decomposition. For one set of experimental parameters, mild heating is found to increase the energy content of the dominant helical mode. Strong heating leads to a reduction by 30\\% of the coherent structures energy. For a second set of experimental parameters, no alteration of the dominant coherent structure is detectable. Local linear stability analysis of the time-averaged velocity fields shows that the key difference between the two configurations is the density ratio at the respective w...

  12. Generalized connected domination in graphs

    Directory of Open Access Journals (Sweden)

    M. Kouider

    2006-01-01

    Full Text Available As a generalization of connected domination in a graph G we consider domination by sets having at most k components. The order γ c k (G of such a smallest set we relate to γ c (G, the order of a smallest connected dominating set. For a tree T we give bounds on γ c k (T in terms of minimum valency and diameter. For trees the inequality γ c k (T≤ n-k-1 is known to hold, we determine the class of trees, for which equality holds.

  13. Particle Size Distributions Measured in the Stratospheric Plumes of Three Rockets During the ACCENT Missions

    Science.gov (United States)

    Wiedinmyer, C.; Brock, C. A.; Reeves, J. M.; Ross, M. N.; Schmid, O.; Toohey, D.; Wilson, J. C.

    2001-12-01

    The global impact of particles emitted by rocket engines on stratospheric ozone is not well understood, mainly due to the lack of comprehensive in situ measurements of the size distributions of these emitted particles. During the Atmospheric Chemistry of Combustion Emissions Near the Tropopause (ACCENT) missions in 1999, the NASA WB-57F aircraft carried the University of Denver N-MASS and FCAS instruments into the stratospheric plumes from three rockets. Size distributions of particles with diameters from 4 to approximately 2000 nm were calculated from the instrument measurements using numerical inversion techniques. The data have been averaged over 30-second intervals. The particle size distributions observed in all of the rocket plumes included a dominant mode near 60 nm diameter, probably composed of alumina particles. A smaller mode at approximately 25 nm, possibly composed of soot particles, was seen in only the plumes of rockets that used liquid oxygen and kerosene as a propellant. Aircraft exhaust emitted by the WB-57F was also sampled; the size distributions within these plumes are consistent with prior measurements in aircraft plumes. The size distributions for all rocket intercepts have been fitted to bimodal, lognormal distributions to provide input for global models of the stratosphere. Our data suggest that previous estimates of the solid rocket motor alumina size distributions may underestimate the alumina surface area emission index, and so underestimate the particle surface area available for heterogeneous chlorine activation reactions in the global stratosphere.

  14. Aerosol particle size distributions in the lower Fraser Valley: evidence for particle nucleation and growth

    Directory of Open Access Journals (Sweden)

    M. Mozurkewich

    2004-01-01

    Full Text Available Particle size distributions from 9 to 640nm diameter were measured at Eagle Ridge in the lower Fraser Valley from 13 August to 1 September 2001 as part of the Pacific 2001 Air Quality Study. The site was on top of a ridge, about 300m above the valley floor, in a predominantly agricultural area about 70km ESE of Vancouver. To further characterize the particles, their hygroscopic properties (affinity for water were measured. The maximum of the number distributions was generally between 40 and 100nm diameter, but the number distribution was sometimes dominated by ultrafine particles with diameters below 40nm. These ultrafine particles, which appeared to some extent on all days, were frequently associated with elevated levels of CO and NOx, as expected for fresh vehicular emissions. The appearance of these fresh emissions was most pronounced when the growing mixed layer reached the altitude of the site. In contrast, pronounced nucleation events occurred on the five cleanest days; these resulted in particle number concentrations as high as 5x104 particles cm-3 and growth rates of 5 to 10nmhr-1. Nucleation appears to have been triggered when the UV flux reached about 25Wm-2. The growth of these newly formed particles was probably driven by the photochemical oxidation of biogenic organic compounds. Dramatic growth events were also observed on the afternoons of the more polluted days; these produced an extremely narrow mode σ<0.3 at a diameter of about 40nm. Rainy days showed low number concentrations with the size distributions shifted to small sizes. On one of these days there was evidence of nucleation not far from the site; this may have been occurring in the vicinity of the clouds.

  15. Superhorizon entanglement entropy from particle decay in inflation

    Energy Technology Data Exchange (ETDEWEB)

    Lello, L.; Boyanovsky, D. [Department of Physics and Astronomy, University of Pittsburgh,3941 O’Hara St, Pittsburgh, PA 15260 (United States); Holman, R. [Department of Physics, Carnegie Mellon University,5000 Forbes Ave., Pittsburgh, PA 15260 (United States)

    2014-04-08

    In inflationary cosmology all particle states decay as a consequence of the lack of kinematic thresholds. The decay of an initial single particle state yields an entangled quantum state of the product particles. We generalize and extend a manifestly unitary field theoretical method to obtain the time evolution of the quantum state. We consider the decay of a light scalar field with mass M≪H with a cubic coupling in de Sitter space-time. Radiative corrections feature an infrared enhancement manifest as poles in Δ=M{sup 2}/3H{sup 2} and we obtain the quantum state in an expansion in Δ. To leading order the pure state density matrix describing the decay of a particle with sub-horizon wavevector is dominated by the emission of superhorizon quanta, describing entanglement between superhorizon and subhorizon fluctuations and correlations across the horizon. Tracing over the superhorizon degrees of freedom yields a mixed state density matrix from which we obtain the entanglement entropy. Asymptotically this entropy grows with the physical volume as a consequence of more modes of the decay products crossing the Hubble radius. A generalization to localized wave packets is provided. The cascade decay of single particle states into many particle states is discussed. We conjecture on possible impact of these results on non-gaussianity and on the “low multipole anomalies” of the CMB.

  16. Cosmic Super-Strings and Kaluza-Klein Modes

    CERN Document Server

    Dufaux, Jean-Francois

    2012-01-01

    Cosmic super-strings interact generically with a tower of relatively light and/or strongly coupled Kaluza-Klein (KK) modes associated with the geometry of the internal space. In this paper, we study the production of spin-2 KK particles by cusps on loops of cosmic F- and D-strings. We consider cosmic super-strings localized either at the bottom of a warped throat or in a flat internal space with large volume. The total energy emitted by cusps in KK modes is comparable in both cases, although the number of produced KK modes may differ significantly. We then show that KK emission is constrained by the photo-dissociation of light elements and by observations of the diffuse gamma ray background. We study the resulting constraints on the parameter space of cosmic super-strings and highlight their complementarity with the regions that can be probed by current and upcoming gravitational wave experiments. KK modes are also expected to play an important role in the friction-dominated epoch of cosmic super-string evolu...

  17. A modified relativistic magnetron with TEM output mode

    Science.gov (United States)

    Shi, Di-Fu; Qian, Bao-Liang; Wang, Hong-Gang; Li, Wei; Ju, Jin-Chuan; Du, Guang-Xing

    2017-01-01

    A modified relativistic magnetron (RM) with TEM output mode is proposed. By setting the coupling slots at the bottom of the resonant cavities in the transmission region rather than in the interaction region, besides possessing the original RM's advantages of high power conversion efficiency and radiating the lowest order mode, the modified RM not only improves the compactness and miniaturization of the magnetic field system, which is beneficial to realize the RMs packed by a permanent magnet, but also improves the robustness of operating frequency to structural perturbations of the coupling slots, which contributes to optimize the RM performance by adjusting the coupling slot dimensions with a relatively stable operating frequency. In the three-dimensional particle-in-cell (PIC) simulation, the modified RM with a reduction of 27.2% in the weight of the coils, 35.8% in the occupied space of the coils, and 18.6% in the operating current, can output a relatively pure TEM mode, which has been demonstrated as the dominant output mode by simulation, corresponding to an output power of 495.0 MW and a power conversion efficiency of 56.4%, at the resonant frequency of 4.30 GHz. In addition, an output power of above 2 GW can also be obtained from the RM in simulations.

  18. Causality and Primordial Tensor Modes

    CERN Document Server

    Baumann, Daniel

    2009-01-01

    We introduce the real space correlation function of $B$-mode polarization of the cosmic microwave background (CMB) as a probe of superhorizon tensor perturbations created by inflation. By causality, any non-inflationary mechanism for gravitational wave production after reheating, like global phase transitions or cosmic strings, must have vanishing correlations for angular separations greater than the angle subtended by the particle horizon at recombination, i.e. $\\theta \\gtrsim 2^\\circ$. Since ordinary $B$-modes are defined non-locally in terms of the Stokes parameters $Q$ and $U$ and therefore don't have to respect causality, special care is taken to define `causal $\\tilde B$-modes' for the analysis. We compute the real space $\\tilde B$-mode correlation function for inflation and discuss its detectability on superhorizon scales where it provides an unambiguous test of inflationary gravitational waves. The correct identification of inflationary tensor modes is crucial since it relates directly to the energy s...

  19. Dominant investors and strategic transparency

    NARCIS (Netherlands)

    E.C. Perotti; E.-L. von Thadden

    1999-01-01

    This paper studies product market competition under a strategic transparency decision. Dominant investors can influence information collection in the financial market, and thereby corporate transparency, by affecting market liquidity or the cost of information collection. More transparency on a firm

  20. Dominant investors and strategic transparency

    NARCIS (Netherlands)

    E.C. Perotti; E.-L. von Thadden

    1998-01-01

    This paper studies product market competition under a strategic transparency decision. Dominant investors can influence information collection in the financial market, and thereby corporate transparency, by affecting market liquidity or the cost of information collection. More transparency on a firm

  1. Modeling vapor dominated geothermal reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Marconcini, R.; McEdwards, D.; Neri, G.; Ruffilli, C.; Schroeder, R.; Weres, O.; Witherspoon, P.

    1977-09-12

    The unresolved questions with regard to vapor-dominated reservoir production and longevity are reviewed. The simulation of reservoir behavior and the LBL computer program are discussed. The geology of Serrazzano geothermal field and its reservoir simulation are described. (MHR)

  2. Failure Modes

    DEFF Research Database (Denmark)

    Jakobsen, K. P.; Burcharth, H. F.; Ibsen, Lars Bo;

    1999-01-01

    The present appendix contains the derivation of ten different limit state equations divided on three different failure modes. Five of the limit state equations can be used independently of the characteristics of the subsoil, whereas the remaining five can be used for either drained or undrained...

  3. Analysis of Alfven Eigenmodes destabilization by fast particles in Large Helical Device

    Science.gov (United States)

    Varela, Jacobo; Spong, Donald; Garcia, Luis

    2016-10-01

    Fast particle populations in nuclear fusion experiments can destabilize Alfven Eigenmodes through inverse Landau damping and couplings with gap modes in the shear Alfven continua. We use the reduced MHD equations to describe the linear evolution of the poloidal flux and the toroidal component of the vorticity in a full 3D system, coupled with equations of density and parallel velocity moments for the energetic particles. We add the Landau damping and resonant destabilization effects by a closure relation. We apply this model to study the Alfven modes stability in Large Helical Device (LHD) equilibria for inward configurations, performing a parametric analysis along a range of realistic values of fast particle β (βfp), ratios of thermal/Alfven velocities (Vth/Vao), magnetic Lundquist numbers (S) and dominant toroidal (n) modes families. The n = 1 and n =2 toroidal families show the largest growth rates for parameters closer to a real LHD scenario (S = 5E6, βfp = 0.02 and Vth/Vao = 0.5), particularly the modes n/m = 1/2 and 2/4 located the inner and middle plasma (ρ = 0.25 - 0.5 with ρ the normalized minor radius). The n = 3 and n = 4 toroidal families are weakly perturbed by fast particles.

  4. The physics mechanisms of the weakly coherent mode in the Alcator C-Mod Tokamak

    Science.gov (United States)

    Liu, Z. X.; Xu, X. Q.; Gao, X.; Hubbard, A. E.; Hughes, J. W.; Walk, J. R.; Theiler, C.; Xia, T. Y.; Baek, S. G.; Golfinopoulos, T.; Whyte, D.; Zhang, T.; Li, J. G.

    2016-12-01

    The weakly coherent mode (WCM) in I-mode has been studied by a six-field two-fluid model based on the Braginskii equations under the BOUT++ framework for the first time. The calculations indicate that a tokamak pedestal exhibiting a WCM is linearly unstable to drift Alfven wave (DAW) instabilities and the resistive ballooning mode. The nonlinear simulation shows promising agreement with the experimental measurements of the WCM. The shape of the density spectral and location of the spectral peak of the dominant toroidal number mode n = 20 agrees with the experimental data from reflectometry. The simulated mode propagates in electron diamagnetic direction is consistent with the results from the magnetic probes in the laboratory frame, a large ratio of particle to heat diffusivity is consistent with the distinctive experimental feature of I-mode, and the value of the simulated χe at the edge is in the range of experimental errors of χeff from the experiment. The prediction of the WCM shows that free energy is mainly provided by the electron pressure gradient, which gives guidance for pursuing future I-mode studies.

  5. Restrained roman domination in graphs

    Directory of Open Access Journals (Sweden)

    Roushini Leely Pushpam

    2015-03-01

    Full Text Available A Roman dominating function (RDF on a graph G = (V,E is defined to be a function satisfying the condition that every vertex u for which f(u = 0 is adjacent to at least one vertex v for which f(v = 2. A set S V is a Restrained dominating set if every vertex not in S is adjacent to a vertex in S and to a vertex in . We define a Restrained Roman dominating function on a graph G = (V,E to be a function satisfying the condition that every vertex u for which f(u = 0 is adjacent to at least one vertex v for which f(v = 2 and at least one vertex w for which f(w = 0. The weight of a Restrained Roman dominating function is the value . The minimum weight of a Restrained Roman dominating function on a graph G is called the Restrained Roman domination number of G and denoted by . In this paper, we initiate a study of this parameter.

  6. Number size distributions and seasonality of submicron particles in Europe 2008–2009

    Directory of Open Access Journals (Sweden)

    A. Asmi

    2011-06-01

    from several source regions; the Mediterranean aerosol exhibit high seasonality, and a strong accumulation mode in the summer. The greatest concentrations were observed at the Ispra station in Northern Italy with high accumulation mode number concentrations in the winter. The aerosol number concentrations at the Arctic station Zeppelin in Ny-AA lesund in Svalbard have also a strong seasonal cycle, with greater concentrations of accumulation mode particles in winter, and dominating summer Aitken mode indicating more recently formed particles. Observed particles did not show any statistically significant regional work-week or weekday related variation in number concentrations studied.

    Analysis products are made for open-access to the research community, available in a freely accessible internet site. The results give to the modelling community a reliable, easy-to-use and freely available comparison dataset of aerosol size distributions.

  7. Contributions to the 1999 particle accelerator conference

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, M. [Laboratoire de l' Accelerateur Lineaire, 91 - Orsay (France); Fartoukh, S.; Jablonka, M.; Joly, J.M.; Lalot, M.; Magne, C.; Napoly, O. [CEA/Saclay, 91 - Gif sur Yvette (France); Baboi, N.; Schreiber, S.; Simrock, S.; Weise, H. [DESY, Hamburg (Germany)

    2000-06-01

    This document puts together the 10 contributions of the laboratory to the 1999 particle accelerator conference. The titles of the papers are: 1) Evidence for a strongly coupled dipole mode with insufficient damping in the first accelerating module of the TESLA test facility (TTF); 2) An alternative scheme for stiffening superconducting RF cavities by plasma spraying; 3) A laser triggered electron source for pulsed radiolysis; 4) A cure for the energy spread increasing related bunch lengthening in electron storage rings; 5) Single bunch longitudinal instabilities in proton storage rings; 6) Analytical investigation on the halo formation in space charge dominated beams; 7) Analytical investigation on the dynamic apertures of circular accelerators; 8) The intrinsic upper limit to the beam energy of an electron-positron circular collider; 9) Coaxial disc windows for a high power superconducting cavity input coupler; and 10) RF pulsed tests on 3 GHz niobium cavities.

  8. On Gaugino Dominated Dark Matter

    CERN Document Server

    Ennadifi, S E; 10.4236/jmp.2010.16056

    2011-01-01

    Using the neutral gauginos of SU(2)L* U(1)Y and hybridization ideas below the GUT scale, we approach the Dark Matter particle within the Minimal Supersymmetric Standard Model. In the energy range MGUT-MZ where supergravity effects can be ignored, it is proposed that such DM particle could be interpreted in terms of a mixture of Bino and Wino states with a lower bound mass MDM sup or eq to 65GeV not far above the electroweak scale to account for the observed Dark Matter density. We establish the theoretical origin of this particle and study as well its compositeness and its mass bound.

  9. Generating Color from Polydisperse, Near Micron-Sized TiO2 Particles.

    Science.gov (United States)

    Alam, Al-Mahmnur; Baek, Kyungnae; Son, Jieun; Pei, Yi-Rong; Kim, Dong Ha; Choy, Jin-Ho; Hyun, Jerome K

    2017-07-19

    Single particle Mie calculations of near micron-sized TiO2 particles predict strong light scattering dominating the visible range that would give rise to a white appearance. We demonstrate that a polydisperse collection of these "white" particles can result in the generation of visible colors through ensemble scattering. The weighted averaging of the scattering over the particle size distribution modifies the sharp, multiple, high order scattering modes from individual particles into broad variations in the collective extinction. These extinction variations are apparent as visible colors for particles suspended in organic solvent at low concentration, or for a monolayer of particles supported on a transparent substrate viewed in front of a white light source. We further exploit the color variations on optical sensitivity to the surrounding environment to promote micron-sized TiO2 particles as stable and robust agents for detecting the optical index of homogeneous media with high contrast sensitivities. Such distribution-modulated scattering properties provide TiO2 particles an intriguing opportunity to impart color and optical sensitivity to their widespread electronic and chemical platforms such as antibacterial windows, catalysis, photocatalysis, optical sensors, and photovoltaics.

  10. Dynamic rotor mode in antiferromagnetic nanoparticles

    DEFF Research Database (Denmark)

    Lefmann, Kim; Jacobsen, H.; Garde, J.

    2015-01-01

    We present experimental, numerical, and theoretical evidence for an unusual mode of antiferromagnetic dynamics in nanoparticles. Elastic neutron scattering experiments on 8-nm particles of hematite display a loss of diffraction intensity with temperature, the intensity vanishing around 150 K...

  11. Toward integrated multi-scale pedestal simulations including edge-localized-mode dynamics, evolution of edge-localized-mode cycles, and continuous fluctuations

    Science.gov (United States)

    Xu, X. Q.; Xia, T. Y.; Yan, N.; Liu, Z. X.; Kong, D. F.; Diallo, A.; Groebner, R. J.; Hubbard, A. E.; Hughes, J. W.

    2016-05-01

    The high-fidelity BOUT++ two-fluid code suite has demonstrated significant recent progress toward integrated multi-scale simulations of tokamak pedestal, including Edge-Localized-Mode (ELM) dynamics, evolution of ELM cycles, and continuous fluctuations, as observed in experiments. Nonlinear ELM simulations show three stages of an ELM event: (1) a linear growing phase; (2) a fast crash phase; and (3) a slow inward turbulence spreading phase lasting until the core heating flux balances the ELM energy loss and the ELM is terminated. A new coupling/splitting model has been developed to perform simulations of multi-scale ELM dynamics. Simulation tracks five ELM cycles for 10 000 Alfvén times for small ELMs. The temporal evolution of the pedestal pressure is similar to that of experimental measurements for the pedestal pressure profile collapses and recovers to a steep gradient during ELM cycles. To validate BOUT++ simulations against experimental data and develop physics understanding of the fluctuation characteristics for different tokamak operation regimes, both quasi-coherent fluctuations (QCFs) in ELMy H-modes and Weakly Coherent Modes in I-modes have been simulated using three dimensional 6-field 2-fluid electromagnetic model. The H-mode simulation results show that (1) QCFs are localized in the pedestal region having a predominant frequency at f ≃300 -400 kHz and poloidal wavenumber at kθ≃0.7 cm-1 , and propagate in the electron diamagnetic direction in the laboratory frame. The overall signatures of simulation results for QCFs show good agreement with C-Mod and DIII-D measurements. (2) The pedestal profiles giving rise to QCFs are near the marginal instability threshold for ideal peeling-ballooning modes for both C-Mod and DIII-D, while the collisional electromagnetic drift-Alfvén wave appears to be dominant for DIII-D. (3) Particle diffusivity is either smaller than the heat diffusivity for DIII-D or similar to the heat diffusivity for C-Mod. Key I-mode

  12. Solar Energetic Particles

    Science.gov (United States)

    Király, Péter

    Energetic particles recorded in the Earth environment and in interplanetary space have a multitude of origins, i.e. acceleration and propagation histories. At early days practically all sufficiently energetic particles were considered to have come either from solar flares or from interstellar space. Later on, co-rotating interplanetary shocks, the termination shock of the supersonic solar wind, planetary bow shocks and magnetospheres, and also coronal mass ejections (CME) were recognized as energetic particle sources. It was also recognized that less energetic (suprathermal) particles of solar origin and pick-up ions have also a vital role in giving rise to energetic particles in interplanetary disturbances. The meaning of the term "solar energetic particles" (SEP) is now somewhat vague, but essentially it refers to particles produced in disturbances fairly directly related to solar processes. Variation of intensity fluctuations with energy and with the phase of the solar cycle will be discussed. Particular attention will be given to extremes of time variation, i.e. to very quiet periods and to large events. While quiet-time fluxes are expected to shed light on some basic coronal processes, large events dominate the fluctuation characteristics of cumulated fluence, and the change of that fluctuation with energy and with the phase of the solar cycle may also provide important clues. Mainly ISEE-3 and long-term IMP-8 data will be invoked. Energetic and suprathermal particles that may never escape into interplanetary space may play an important part in heating the corona of the sun.

  13. Modulation on flow field by solid particles in gas-solid two-phase turbulent free shear flows

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In order to understand the interaction between fluid and particles, a two-way coupled three-dimensional mixing layer laden with particles at a Stokes number of 5 with different mass loadings is numerically studied. The pseudospectral method is used for the flow fluid and the Lagrangian approach is used to trace particles. The concept of computational particles is introduced to vary the mass loading of particles. The momentum coupling effect introduced by a particle is approximated to the point force. The simulation results show that the coherent structures are still dominant in the mixing layer, but the flow field is modulated by particles. The addition of the particles enhances the energy of all the Fourier modes with non-zero spanwise wavenumber, and the enhancement increases with the augment of the mass loading. A higher mass loading results in a lower energy at fundamental wavenumber and streamwise subharmonic Fourier mode of the fluid in the phase of Kelvin-Helmholtz rolling up, but for large-scale vortex structures pairing, the energy of the fluid increases as the mass loading increases. Similar trends can also be found in the developments of the turbulent kinetic energy and the momentum thickness.

  14. The relationship between acoustic radiation modes and structural modes and its applications

    Institute of Scientific and Technical Information of China (English)

    LI Shuang; CHEN Ke'an

    2007-01-01

    Both acoustic radiation modes and structural modes play an important role in the field of structure-borne sound, however, little work has been done for inherent relations between these two kinds of modes. This paper is focused on the relationship between the radiation modes and structural modes and its physical mechanisms. First, a governing equation for relating the radiation mode and structural mode is given based on the characteristics of the modes. Then, using the symmetric or anti-symmetric properties of two kinds of modes, the corresponding relations are presented. And then, numerical examples are given to verify the theoretical investigations, and it has been shown that, for a simply supported rectangular panel vibrating at low frequencies, the first radiation mode is dominant corresponding to (odd, odd)structural modes; the following radiation modes are respectively dominant corresponding to (even, odd), (odd, even), and (even, even) structural modes. Finally, such relations are applied to active acoustic structural control and provide a direct help for the design of active control strategy and arrangement of the secondary forces.

  15. Velocity Fluctuations Driven by the Damped, Aperiodic Mode in the Intergalactic Medium

    Science.gov (United States)

    Kolberg, U.; Schlickeiser, R.; Yoon, P. H.

    2017-08-01

    On account of its finite temperature, the unmagnetized intergalactic medium (IGM) is subject to thermal fluctuations. Due to the fundamental coupling between particles and fields in a plasma, the field fluctuations generate current densities by means of the Lorentz force and thereby affect both the density and the velocity fluctuations of the particles. Recently, a new damped, aperiodic mode was discovered that dominates field fluctuations in the IGM. Apart from its impact on the transport properties of the IGM that determine the propagation of cosmic rays, previous research has shown that this mode provides turbulent magnetic seed fields of 6× {10}-18 {{G}} that are an essential ingredient in the generation of cosmic magnetic fields. The current investigation addresses the influence of the mode on the particle motion. In order to describe the corresponding state of the turbulence, both the spectrum and the integrated total value of the mode-driven proton velocity fluctuations are computed. It is found that the latter amounts to 1.16× {10}8{ T}47/2{n}-7-1/2 {cm} {{{s}}}-1 assuming a temperature of {T}e={T}p={10}4{T}4 {{K}} and a density of {n}e={n}p={10}-7{n}-7 {{cm}}-3. This value is two orders of magnitude larger than the thermal velocity. If the IGM neutrals adopt the same velocities as the protons by mutual charge exchange and elastic collisions (ambipolar diffusion), atomic lines propagating through the IGM are expected to display spectral broadening, enhanced by a factor of 90 beyond the thermal level in the case of hydrogen. This opens the window to a first direct observation of the damped aperiodic mode. Other observational techniques such as dispersion measure, rotation measure, and scintillation data are not applicable in this case because the mode is a transverse one, and, as such, it does not induce the required density fluctuations, as is shown here.

  16. Vector-meson dominance revisited

    Directory of Open Access Journals (Sweden)

    Terschlüsen Carla

    2012-12-01

    Full Text Available The interaction of mesons with electromagnetism is often well described by the concept of vector-meson dominance (VMD. However, there are also examples where VMD fails. A simple chiral Lagrangian for pions, rho and omega mesons is presented which can account for the respective agreement and disagreement between VMD and phenomenology in the sector of light mesons.

  17. Dominant resistance against plant viruses

    NARCIS (Netherlands)

    Ronde, de D.; Butterbach, P.B.E.; Kormelink, R.J.M.

    2014-01-01

    To establish a successful infection plant viruses have to overcome a defense system composed of several layers. This review will overview the various strategies plants employ to combat viral infections with main emphasis on the current status of single dominant resistance (R) genes identified agains

  18. Hand dominance in orthopaedic surgeons.

    LENUS (Irish Health Repository)

    Lui, Darren F

    2012-08-01

    Handedness is perhaps the most studied human asymmetry. Laterality is the preference shown for one side and it has been studied in many aspects of medicine. Studies have shown that some orthopaedic procedures had poorer outcomes and identified laterality as a contributing factor. We developed a questionnaire to assess laterality in orthopaedic surgery and compared this to an established scoring system. Sixty-two orthopaedic surgeons surveyed with the validated Waterloo Handedness Questionnaire (WHQ) were compared with the self developed Orthopaedic Handedness Questionnaire (OHQ). Fifty-eight were found to be right hand dominant (RHD) and 4 left hand dominant (LHD). In RHD surgeons, the average WHQ score was 44.9% and OHQ 15%. For LHD surgeons the WHQ score was 30.2% and OHQ 9.4%. This represents a significant amount of time using the non dominant hand but does not necessarily determine satisfactory or successful dexterity transferable to the operating room. Training may be required for the non dominant side.

  19. Dominance and Age in Bilingualism

    Science.gov (United States)

    Birdsong, David

    2014-01-01

    The present article examines the relationship between age and dominance in bilingual populations. Age in bilingualism is understood as the point in development at which second language (L2) acquisition begins and as the chronological age of users of two languages. Age of acquisition (AoA) is a factor in determining which of a bilingual's two…

  20. Ergodic averages via dominating processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Mengersen, Kerrie

    2006-01-01

    We show how the mean of a monotone function (defined on a state space equipped with a partial ordering) can be estimated, using ergodic averages calculated from upper and lower dominating processes of a stationary irreducible Markov chain. In particular, we do not need to simulate the stationary ...

  1. Genetics of the dominant ataxias

    NARCIS (Netherlands)

    Verbeek, Dineke S.; van de Warrenburg, Bart P. C.

    2011-01-01

    The relevant clinical, genetic, and cell biologic aspects of the dominantly inherited spinocerebellar ataxias (SCAs) are reviewed in this article. SCAs are diseases of the entire nervous system; in addition to cerebellar ataxia, the central (but not obligate) disease feature, many noncerebellar comp

  2. Are Quasar Jets Dominated by Poynting Flux?

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, M

    2005-02-02

    The formation of relativistic astrophysical jets is presumably mediated by magnetic fields threading accretion disks and central, rapidly rotating objects. As it is accelerated by magnetic stresses, the jet's kinetic energy flux grows at the expense of its Poynting flux. However, it is unclear how efficient is the conversion from magnetic to kinetic energy and whether there are any observational signatures of this process. We address this issue in the context of jets in quasars. Using data from all spatial scales, we demonstrate that in these objects the conversion from Poynting-flux-dominated to matter-dominated jets is very likely to take place closer to the black hole than the region where most of the Doppler boosted radiation observed in blazars is produced. We briefly discuss the possibility that blazar activity can be induced by global MHD instabilities, e.g., via the production of localized velocity gradients that lead to dissipative events such as shocks or magnetic reconnection, where acceleration of relativistic particles and production of non-thermal flares is taking place.

  3. Transport and micro-instability analysis of JET H-mode plasma during pellet fueling

    Science.gov (United States)

    Klaywittaphat, P.; Onjun, T.

    2017-02-01

    Transport and micro-instability analysis in a JET H-mode plasma discharge 53212 during the pellet fueling operation is carried out using the BALDUR integrated predictive modeling code with a combination of the NCLASS neoclassical transport model and an anomalous core transport model (either Mixed B/gB or MMM95 model). In this work, the evolution of plasma current, plasma density and temperature profiles is carried out and, consequently, the plasma’s behaviors during the pellet operation can be observed. The NGS pellet model with the Grad-B drift effect included is used to describe pellet ablation and its behaviors when a pellet is launched into hot plasma. The simulation shows that after each pellet enters the plasma, there is a strong perturbation on the plasma causing a sudden change of both thermal and particle profiles, as well as the thermal and particle transports. For the simulation using MMM95 transport model, the change of both thermal and particle transports during pellet injection are found to be dominated by the transport due to the resistive ballooning modes due to the increase of collisionality and resistivity near the plasma edge. For the simulation based on mixed B/gB transport model, it is found that the change of transport during the pellet injection is dominated by the Bohm term. Micro-instability analysis of the plasma during the time of pellet operation is also carried out for the simulations based on MMM95 transport model. It is found that the ion temperature gradient mode is destabilized due to an increase of temperature gradient in the pellet effective region, while the trapped electron mode is stabilized due to an increase of collisionality in that region.

  4. Predictive nonlinear studies of TAE-induced alpha-particle transport in the Q  =  10 ITER baseline scenario

    Science.gov (United States)

    Fitzgerald, M.; Sharapov, S. E.; Rodrigues, P.; Borba, D.

    2016-11-01

    We use the HAGIS code to compute the nonlinear stability of the Q  =  10 ITER baseline scenario to toroidal Alfvén eigenmodes (TAE) and the subsequent effects of these modes on fusion alpha-particle redistribution. Our calculations build upon an earlier linear stability survey (Rodrigues et al 2015 Nucl. Fusion 55 083003) which provides accurate values of bulk ion, impurity ion and electron thermal Landau damping for our HAGIS calculations. Nonlinear calculations of up to 129 coupled TAEs with toroidal mode numbers in the range n  =  1-35 have been performed. The effects of frequency sweeping were also included to examine possible phase space hole and clump convective transport. We find that even parity core localised modes are dominant (expected from linear theory), and that linearly stable global modes are destabilised nonlinearly. Landau damping is found to be important in reducing saturation amplitudes of coupled modes to below δ {{B}r}/{{B}0}˜ 3× {{10}-4} . For these amplitudes, stochastic transport of alpha-particles occurs in a narrow region where predominantly core localised modes are found, implying the formation of a transport barrier at r/a≈ 0.5 , beyond which, the weakly driven global modes are found. We find that for flat q profiles in this baseline scenario, alpha particle transport losses and redistribution by TAEs is minimal.

  5. Cluster observations of trapped ions interacting with magnetosheath mirror modes

    Directory of Open Access Journals (Sweden)

    J. Soucek

    2011-06-01

    Full Text Available Mirror modes are among the most intense low frequency plasma wave phenomena observed in the magnetosheaths of magnetized planets. They appear as large amplitude non-propagating fluctuations in the magnetic field magnitude and plasma density. These structures are widely accepted to represent a non-linear stage of the mirror instability, dominant in plasmas with large ion beta and a significant ion temperature anisotropy T/T>1. It has long been recognized that the mirror instability both in the linear and non-linear stage is a kinetic process and that the behavior of resonant particles at small parallel velocities is crucial for its development and saturation. While the dynamics of the instability and the effect of trapped particles have been studied extensively in theoretical models and numerical simulations, only spurious observations of the trapped ions were published to date. In this work we used data from the Cluster spacecraft to perform the first detailed experimental study of ion velocity distribution associated with mirror mode oscillations. We show a conclusive evidence for the predicted cooling of resonant ions at small parallel velocities and heating of trapped ions at intermediate pitch angles.

  6. Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2008-08-01

    Full Text Available Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS were made in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area-2006 campaign (MCMA-2006. Results are presented for the period of 15–27 March 2006. The submicron size mode contained both fresh and aged biomass burning, aged organic carbon (OC mixed with nitrate and sulfate, elemental carbon (EC, nitrogen-organic carbon, industrial metal, and inorganic NaK inorganic particles. Overall, biomass burning and aged OC particle types comprised 40% and 31%, respectively, of the submicron mode. In contrast, the supermicron mode was dominated by inorganic NaK particle types (42% which represented a mixture of dry lake bed dust and industrial NaK emissions mixed with soot. Additionally, aluminosilicate dust, transition metals, OC, and biomass burning contributed to the supermicron particles. Early morning periods (2–6 a.m. showed high fractions of inorganic particles from industrial sources in the northeast, composed of internal mixtures of Pb, Zn, EC and Cl, representing up to 73% of the particles in the 0.2–3μm size range. A unique nitrogen-containing organic carbon (NOC particle type, peaking in the early morning hours, was hypothesized to be amines from local industrial emissions based on the time series profile and back trajectory analysis. A strong dependence on wind speed and direction was observed in the single particle types that were present during different times of the day. The early morning (3:30–10 a.m. showed the greatest contributions from industrial emissions. During mid to late mornings (7–11 a.m., weak northerly winds were observed along with the most highly aged particles. Stronger winds from the south picked up in the late morning (after 11 a.m., resulting in a decrease in the concentrations of the major aged particle types and an increase in the number fraction of fresh

  7. Optically controllable dual-mode switching in single-mode Fabry-Pérot laser diode subject to one side-mode feedback and external single mode injection

    Science.gov (United States)

    Wu, Jian-Wei; Won, Yong Hyub

    2017-06-01

    In this paper, broadly tunable dual-mode lasing system is presented and demonstrated based on single-mode Fabry-Pérot laser diode subject to the feedback of one side mode amplified by an erbium-doped fiber amplifier in the external feedback cavity. The spacing between two resonance modes in output lasing spectrum is broadly tuned by introducing differently amplified side mode into the single-mode laser via the external cavity consisted of amplifier, filter, and polarization controller so that two difference frequencies of 1 THz and 0.6 THz are given to display the tunable behavior of dual-mode emission in this work. Therefore, under an external injection mode into the laser condition, the power dependent injection locking and optical bistability of generated dual-mode emission are discussed in detail. At different wavelength detunings, the emitted two resonance modes including the dominant and feedback modes are switched to on- or off-state by selecting proper high-low power level of the external injection mode. As a consequence, the maximum value of achieved dual-mode on-off ratio is as high as up to 45 dB.

  8. Dynamics of an unsteady stagnation vortical flow via dynamic mode decomposition analysis

    Science.gov (United States)

    Pan, Chong; Wang, Jianjie; Wang, Jinjun; Sun, Mao

    2017-03-01

    The dynamics of a large-scale stagnation vortex pair in an axisymmetric stagnation flow subject to a laminar wake disturbance is measured by time-resolved two-dimensional particle image velocimetry, and then quantitatively characterized by both the Eulerian velocity/vorticity fields and the Lagrangian finite-time Lyapunov exponents fields. This vortex pair is found to be the result of the forced response of the stagnation flow to the upstream shearing disturbances, and presents a dynamical evolution of quasi-periodic shedding due to short-wave elliptical instability. Dynamic mode decomposition analysis of both the Eulerian measure and the Lagrangian measure is taken for a quantitative description of this process. The sparsity-promoting scheme (Jovanović et al. Phys Fluids 26(2):024,103, 2014), which integrates the mode identification and truncation as a whole, is used to distinguish those modes with dynamical significance from irrelevant ones with transient behavior. The superiority of this scheme is evidenced by the facts that it avoids the eigenvalue contamination problem, and credits higher priority to the sub-dominant modes directly associated with the system dynamics. It is found that the energetic mode with a frequency of 0.177 Hz, or about 10% of the maximum shear rate of the upstream wake, determines the quasi-periodical vortex formation process. Its half-order harmonic represents the vortex shedding event along one fixed direction. High-order even-quarter harmonics jointly contribute to the circular pattern of the vortex tube. In addition, a set of low-frequency odd-quarter harmonics are highlighted as the elliptical instability and the following vortex deformation process. Based on this finding, a reduce-order representation with 8 Eulerian modes or 56 Lagrangian modes is proposed to characterize the dominant dynamics of this unsteady vortical stagnation flow. In addition, the Eulerian measure seems to be more efficient than the Lagrangian measure in

  9. From nature-dominated to human-dominated environmental changes

    Science.gov (United States)

    Messerli, Bruno; Grosjean, Martin; Hofer, Thomas; Núñez, Lautaro; Pfister, Christian

    2000-01-01

    To what extent is it realistic and useful to view human history as a sequence of changes from highly vulnerable societies of hunters and gatherers through periods with less vulnerable, well buffered and highly productive agrarian-urban societies to a world with regions of extreme overpopulation and overuse of life support systems, so that vulnerability to climatic-environmental changes and extreme events is again increasing? This question cannot be fully answered in our present state of knowledge, but at least we can try to illustrate, with three case studies from different continents, time periods and ecosystems, some fundamental changes in the relationship between natural processes and human activities that occur, as we pass from a nature-dominated to a human dominated environment. 1. Early-mid Holocene: Nature dominated environment — human adaptation, mitigation, and migration. In the central Andes, the Holocene climate changed from humid (10,800-8000 BP) to extreme arid (8000-3600 BP) conditions. Over the same period, prehistoric hunting communities adopted a more sedentary pattern of resource use by settling close to the few perennial water bodies, where they began the process of domesticating camelids around 5000 BP and irrigation from about 3100 BP. 2. Historical period: An agrarian society in transition from an "enduring" to an innovative human response. Detailed documentary evidence from Western Europe may be used to reconstruct quite precisely the impacts of climatic variations on agrarian societies. The period considered spans a major transition from an apparently passive response to the vagaries of the environment during the 16th century to an active and innovative attitude from the onset of the agrarian revolution in the late 18th century through to the present day. The associated changes in technology and in agricultural practices helped to create a society better able to survive the impact of climatic extremes. 3. The present day: A human dominated

  10. Head tracking based on the integration of two different particle filters

    Science.gov (United States)

    Zhang, Bo; Tian, Weifeng; Jin, Zhihua

    2006-11-01

    Existing methods of improving particle filters mainly focus on two aspects: designing a good proposal distribution before sampling and allocating particles to a high posterior area after sampling. An auxiliary particle filter (APF) is one such simple algorithm belonging to the former aspect, which generates particles from an importance distribution depending on a more recent observation. Its weakness is that it requires a large number of particles. On the other hand, a kernel-based particle filter (KPF), which belongs to the latter aspect, is able to greatly reduce the number of particles required and is still able to capture good characteristics of the posterior density. However, a KPF does not take the current observation into account. To utilize their respective strengths, a new algorithm is proposed in this paper with the combination of an APF and a KPF, the APF for designing good proposal density and the KPF for exploring the dominant mode of the posterior density. Experimental results in several real-tracking scenarios demonstrate that the integrated algorithm surpasses the standard particle filter (SPF) when encountering weak dynamic models. Moreover, the proposed algorithm is also able to achieve a comparable performance with KPF whilst reducing computational cost.

  11. Hardware Assisted ROP Detection Mode (HARD Mode)

    Science.gov (United States)

    2013-08-01

    Distribution A. Cleared for public release; unlimited distribution. USAFA-CN-2013-457 Hardware Assisted ROP Detection Mode (HARD Mode) NATHANIEL HART...457 This report, "Hardware Assisted ROP Detection Mode (HARD Mode)" is presented as a competent treatment of the subj ect, worthy of publication. The...Technical 20120810-20121215 Hardware Assisted ROP Detection Mode (HARD Mode) NATHANIEL HART MICHAEL WINSTEAD MARTIN CARLISLE RODNEY LYKINS MICHAEL

  12. Effects of Mode Shares on Mode Choice

    OpenAIRE

    Carlos Carrion; Nebiyou Tilahun; David Levinson

    2011-01-01

    This study considers the influence of the knowledge of existing mode shares on travelers mode choice. This contrasts with traditional mode choice models, where the main objective is to predict the overall mode shares as the aggregate of individual mode choices according to variables encompassing attributes of the modes, and characteristics of the travelers. In this study, a computer-administered adaptive stated preference survey is developed and applied to a sample of subjects selected from t...

  13. New Solutions for Synchronized Domineering

    Science.gov (United States)

    Bahri, Sahil; Kruskal, Clyde P.

    Cincotti and Iida invented the game of Synchronized Domineering, and analyzed a few special cases. We develop a more general technique of analysis, and obtain results for many more special cases. We obtain complete results for board sizes 3 ×n, 5 ×n, 7 ×n, and 9 ×n (for n large enough) and partial results for board sizes 2×n, 4 ×n, and 6 ×n.

  14. Dominant perceptions on the age

    OpenAIRE

    Komatina Slavica

    2003-01-01

    Contemporary developed society, despite the fact that it is constantly and intensively ageing, is characterized by deeply rooted numerous negative stereotypes on old people and old age as a life period. The study of dominant perceptions on the age of Belgrade population takes not only the universal character of negative connotation of old age into consideration, but also the concrete unfavorable social context. The delicate problematic of stereotypes on old age and old people has been analyze...

  15. Proton: the particle.

    Science.gov (United States)

    Suit, Herman

    2013-11-01

    The purpose of this article is to review briefly the nature of protons: creation at the Big Bang, abundance, physical characteristics, internal components, and life span. Several particle discoveries by proton as the experimental tool are considered. Protons play important roles in science, medicine, and industry. This article was prompted by my experience in the curative treatment of cancer patients by protons and my interest in the nature of protons as particles. The latter has been stimulated by many discussions with particle physicists and reading related books and journals. Protons in our universe number ≈10(80). Protons were created at 10(-6) -1 second after the Big Bang at ≈1.37 × 10(10) years beforethe present. Proton life span has been experimentally determined to be ≥10(34) years; that is, the age of the universe is 10(-24)th of the minimum life span of a proton. The abundance of the elements is hydrogen, ≈74%; helium, ≈24%; and heavier atoms, ≈2%. Accordingly, protons are the dominant baryonic subatomic particle in the universe because ≈87% are protons. They are in each atom in our universe and thus involved in virtually every activity of matter in the visible universe, including life on our planet. Protons were discovered in 1919. In 1968, they were determined to be composed of even smaller particles, principally quarks and gluons. Protons have been the experimental tool in the discoveries of quarks (charm, bottom, and top), bosons (W(+), W(-), Z(0), and Higgs), antiprotons, and antineutrons. Industrial applications of protons are numerous and important. Additionally, protons are well appreciated in medicine for their role in radiation oncology and in magnetic resonance imaging. Protons are the dominant baryonic subatomic particle in the visible universe, comprising ≈87% of the particle mass. They are present in each atom of our universe and thus a participant in every activity involving matter. Copyright © 2013 Elsevier Inc. All

  16. Resistive interchange modes and plasma flow structures

    Science.gov (United States)

    Paccagnella, Roberto

    2011-10-01

    Interchange modes are ubiquitous in magnetic confinement systems and are likely to determine or influence their transport properties. For example a good agreement between theory predictions for linear interchange modes and experimental results has been found recently in a Reverse Field Pinch device. In this work a set of magneto-hydro-dynamic (MHD) equations that describe the dynamical evolution for the pressure driven interchange modes in a magnetic confinement system are studied. Global and local solutions relevant for tokamaks and Reversed Field Pinches (RFPs) configurations are considered. The emphasis is especially in the characterization of the plasma flow structures associated with the dominant modes.

  17. Size-resolved chemical composition, effective density, and optical properties of biomass burning particles

    Science.gov (United States)

    Zhai, Jinghao; Lu, Xiaohui; Li, Ling; Zhang, Qi; Zhang, Ci; Chen, Hong; Yang, Xin; Chen, Jianmin

    2017-06-01

    Biomass burning aerosol has an important impact on the global radiative budget. A better understanding of the correlations between the mixing states of biomass burning particles and their optical properties is the goal of a number of current studies. In this work, the effective density, chemical composition, and optical properties of rice straw burning particles in the size range of 50-400 nm were measured using a suite of online methods. We found that the major components of particles produced by burning rice straw included black carbon (BC), organic carbon (OC), and potassium salts, but the mixing states of particles were strongly size dependent. Particles of 50 nm had the smallest effective density (1.16 g cm-3) due to a relatively large proportion of aggregate BC. The average effective densities of 100-400 nm particles ranged from 1.35 to 1.51 g cm-3 with OC and inorganic salts as dominant components. Both density distribution and single-particle mass spectrometry showed more complex mixing states in larger particles. Upon heating, the separation of the effective density distribution modes confirmed the external mixing state of less-volatile BC or soot and potassium salts. The size-resolved optical properties of biomass burning particles were investigated at two wavelengths (λ = 450 and 530 nm). The single-scattering albedo (SSA) showed the lowest value for 50 nm particles (0.741 ± 0.007 and 0.889 ± 0.006) because of the larger proportion of BC content. Brown carbon played an important role for the SSA of 100-400 nm particles. The Ångström absorption exponent (AAE) values for all particles were above 1.6, indicating the significant presence of brown carbon in all sizes. Concurrent measurements in our work provide a basis for discussing the physicochemical properties of biomass burning aerosol and its effects on the global climate and atmospheric environment.

  18. Interaction between electromagnetic waves and energetic particles by a realistic density model

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Using a realistic density model,we present a first study on the interactions between electromagnetic waves and energetic particles in the inner magnetosphere.Numerical calculations show that as the latitude λ increases,the number density ne increases,and resonant frequency range moves to lower pitch angles.During L-mode/electron and L-mode/proton interactions,the pitch angle diffusion dominates over the momentum diffusion.This indicates that L-mode waves are primarily responsible for pitch angle scattering.For R-mode/electron interaction,the momentum diffusion is found to be comparable to the pitch angle diffusion,implying that R-mode waves can play an important role in both pitch angle scattering and stochastic acceleration of electrons.For R-mode/proton interaction,diffusion coefficients locate primarily below pitch angle 60° and increase as kinetic energy increases,suggesting that R-mode waves have potential for pitch angle scattering of highly energetic (~1 MeV) protons but cannot efficiently accelerate protons.

  19. Inertial modes of slowly rotating isentropic stars

    CERN Document Server

    Yoshida, S; Yoshida, Shijun; Lee, Umin

    2000-01-01

    We investigate inertial mode oscillations of slowly and uniformly rotating, isentropic, Newtonian stars. Inertial mode oscillations are induced by the Coriolis force due to the star's rotation, and their characteristic frequencies are comparable with the rotation frequency $\\Omega$ of the star. So called r-mode oscillations form a sub-class of the inertial modes. In this paper, we use the term ``r-modes'' to denote the inertial modes for which the toroidal motion dominates the spheroidal motion, and the term ``inertial modes'' to denote the inertial modes for which the toroidal and spheroidal motions have comparable amplitude to each other. Using the slow rotation approximation consistent up to the order of $\\Omega^3$, we study the properties of the inertial modes and r-modes, by taking account of the effect of the rotational deformation of the equilibrium on the eigenfrequencies and eigenfunctions. The eigenfrequencies of the r-modes and inertial modes calculated in this paper are in excellent agreement with...

  20. Sequential pole dominance model and decay of new mesons

    CERN Document Server

    Chaichian, Masud

    1976-01-01

    The sequential pole dominance model recently proposed by Freund and Nambu (1975) allows predictions to be made about the decay processes which violate the Zweig-Iizuka rule. Detailed comparison of the model with recent experimental data on the decay modes of psi (3095) and psi '(3684) reveals some quantitative disagreement. A possible decay mechanism which can account for this discrepancy is discussed. (7 refs).

  1. Role of Density Gradient Driven Trapped Electron Modes in the H-Mode Inner Core with Electron Heating

    Science.gov (United States)

    Ernst, D.

    2015-11-01

    We present new experiments and nonlinear gyrokinetic simulations showing that density gradient driven TEM (DGTEM) turbulence dominates the inner core of H-Mode plasmas during strong electron heating. Thus α-heating may degrade inner core confinement in H-Mode plasmas with moderate density peaking. These DIII-D low torque quiescent H-mode experiments were designed to study DGTEM turbulence. Gyrokinetic simulations using GYRO (and GENE) closely match not only particle, energy, and momentum fluxes, but also density fluctuation spectra, with and without ECH. Adding 3.4 MW ECH doubles Te /Ti from 0.5 to 1.0, which halves the linear TEM critical density gradient, locally flattening the density profile. Density fluctuations from Doppler backscattering (DBS) intensify near ρ = 0.3 during ECH, displaying a band of coherent fluctuations with adjacent toroidal mode numbers. GYRO closely reproduces the DBS spectrum and its change in shape and intensity with ECH, identifying these as coherent TEMs. Prior to ECH, parallel flow shear lowers the effective nonlinear DGTEM critical density gradient 50%, but is negligible during ECH, when transport displays extreme stiffness in the density gradient. GS2 predictions show the DGTEM can be suppressed, to avoid degradation with electron heating, by broadening the current density profile to attain q0 >qmin > 1 . A related experiment in the same regime varied the electron temperature gradient in the outer half-radius (ρ ~ 0 . 65) using ECH, revealing spatially coherent 2D mode structures in the Te fluctuations measured by ECE imaging. Fourier analysis with modulated ECH finds a threshold in Te profile stiffness. Supported by the US DOE under DE-FC02-08ER54966 and DE-FC02-04ER54698.

  2. Dominant NNLO Corrections to Four-Fermion Production at the WW Threshold

    CERN Document Server

    Actis, Stefano

    2009-01-01

    The recent evaluation of the parametrically dominant next-to-next-to-leading order corrections to four-fermion production near the W-pair threshold in the framework of unstable-particle effective theory is briefly summarized.

  3. Learning, tracing, and risk dominance

    DEFF Research Database (Denmark)

    Hendon, Ebbe; Jacobsen, Hans Jørgen; Nielsen, Michael Teit;

    1994-01-01

    This paper presents a learning process which is a generalization of the method of fictitious play of Brown. If the learning process converges, the convergence point is a Nash equilibrium. We study 2 × 2 games. Here the process always converges. The relation between the initial prior, the weight...... assigned to this prior, and the equilibrium selected is examined. As the weight increases, the relation between the prior and the equilibrium selected becomes almost identical to that of the tracing procedure of Harsanyi. In this way the learning process supports the concept of risk dominance of Harsanyi...

  4. Causality and primordial tensor modes

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Daniel; Zaldarriaga, Matias, E-mail: dbaumann@physics.harvard.edu, E-mail: mzaldarriaga@cfa.harvard.edu [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138, U.S.A. and Center for Astrophysics, Harvard University, 60 Garden Street, Cambridge, MA 02138 (United States)

    2009-06-01

    We introduce the real space correlation function of B-mode polarization of the cosmic microwave background (CMB) as a probe of superhorizon tensor perturbations created by inflation. By causality, any non-inflationary mechanism for gravitational wave production after reheating, like global phase transitions or cosmic strings, must have vanishing correlations for angular separations greater than the angle subtended by the particle horizon at recombination, i.e. θ ∼> 2°. Since ordinary B-modes are defined non-locally in terms of the Stokes parameters Q and U and therefore don't have to respect causality, special care is taken to define 'causal B-tilde -modes' for the analysis. We compute the real space B-tilde -mode correlation function for inflation and discuss its detectability on superhorizon scales where it provides an unambiguous test of inflationary gravitational waves. The correct identification of inflationary tensor modes is crucial since it relates directly to the energy scale of inflation. Wrongly associating tensor modes from causal seeds with inflation would imply an incorrect inference of the energy scale of inflation. We find that the superhorizon B-tilde -mode signal is above cosmic variance for the angular range 2° < θ < 4° and is therefore in principle detectable. In practice, the signal will be challenging to measure since it requires accurately resolving the recombination peak of the B-mode power spectrum. However, a future CMB satellite (CMBPol), with noise level Δ{sub P} ≅ 1μK-arcmin and sufficient resolution to efficiently correct for lensing-induced B-modes, should be able to detect the signal at more than 3σ if the tensor-to-scalar ratio isn't smaller than r ≅ 0.01.

  5. Ultrafine particle air pollution inside diesel-propelled passenger trains.

    Science.gov (United States)

    Abramesko, Victoria; Tartakovsky, Leonid

    2017-04-05

    Locomotives with diesel engines are used worldwide and are an important source of air pollution. Pollutant emissions by locomotive engines affect the air quality inside passenger trains. This study is aimed at investigating ultrafine particle (UFP) air pollution inside passenger trains and providing a basis for assessing passenger exposure to this pollutant. The concentrations of UFPs inside the carriages of push-pull trains are dramatically higher when the train operates in pull mode. This clearly shows that locomotive engine emissions are a dominant factor in train passengers' exposure to UFPs. The highest levels of UFP air pollution are observed inside the carriages of pull trains close to the locomotive. In push mode, the UFP number concentrations were lower by factors of 2.6-43 (depending on the carriage type) compared to pull mode. The UFP concentrations are substantially lower in diesel multiple-unit trains than in trains operating in pull mode. A significant influence of the train movement regime on the UFP NC inside a carriage is observed.

  6. Chemical mass balance of refractory particles (T=300 °C) at the tropospheric research site Melpitz, Germany

    Science.gov (United States)

    Poulain, L.; Birmili, W.; Canonaco, F.; Crippa, M.; Wu, Z. J.; Nordmann, S.; Spindler, G.; Prévôt, A. S. H.; Wiedensohler, A.; Herrmann, H.

    2013-10-01

    In the fine particle mode (aerodynamic diameter MAAP), and an aerosol mass spectrometer (AMS). The data were collected during two atmospheric field experiments in May/June 2008 as well as February/March 2009. As a basic result, we detected average refractory particle volume fractions of 11±3% (2008) and 17±8% (2009). In both periods, BC was in close linear correlation with the refractory fraction, but not sufficient to quantitatively explain the refractory particle mass concentration. Based on the assumption that BC is not altered by the heating process, the refractory particle mass fraction could be explained by the sum of black carbon BC (47% in summer, 59% in winter) and a refractory organic contribution estimated as part of the Low-Volatility Oxygenated Organic Aerosol (LV-OOA) (53% in summer, 41% in winter); the latter was identified from AMS data by factor analysis. Our results suggest that organics were more volatile in summer (May-June 2008) than in winter (February/March 2009). Although carbonaceous compounds dominated the sub-μm refractory particle mass fraction most of the time, a cross-sensitivity to partially volatile aerosol particles of maritime origin could be seen. These marine particles could be distinguished, however, from the carbonaceous particles by a characteristic particle volume size distribution. The paper discusses the uncertainty of the volatility measurements and outlines the possible merits of volatility analysis as part of continuous atmospheric aerosol measurements.

  7. Effect of particle spatial distribution on particle deposition in ventilation rooms.

    Science.gov (United States)

    Zhao, Bin; Wu, Jun

    2009-10-15

    We used simulations and experimental tests to investigate indoor particle deposition during four commonly used ventilation modes, including ceiling supply, side-up supply, side-down supply and bottom supply. We used a condensation monodisperse aerosol generator to generate fine diethylhexyl sebacate (DEHS) particles of different sizes along with two optical particle counters that measured particle concentration at the exhaust opening and inside a three-dimensional ventilated test room. We then simulated particle deposition using the same ventilation modes with computational fluid dynamics (CFD) method. Our simulated results indicate that mean deposition velocity/rate for particles 0.5-10 microm (aerodynamic diameter) is not affected by different ventilation modes. However, both our experimental and simulated results indicate that the deposition loss factor, a parameter defined based on mass balance principle to reflect the influence of particle distribution on deposited particle quantity, differ significantly by ventilation mode. This indicates that ventilation plays an important role in determining particle deposition due to the apparent differences in the spatial distribution of particles. The particle loss factor during ventilation modes characterized by upward air flow in the room is smaller than that of mixing ventilation; however this trend was strongly influenced by the relative location of the inlets, outlets and aerosol source.

  8. Measurements of radon daughter particle size

    Energy Technology Data Exchange (ETDEWEB)

    Knutson, E.O.; George, A.C.; Knuth, R.H.; Koh, B.R. (Department of Energy, New York (USA). Environmental Measurements Lab.)

    1984-01-01

    Measurements using three types and sizes of diffusion batteries and two cascade impactors showed that the particle size distribution of the potential alpha energy concentration (PAEC) is usually bimodal. The major mode, comprising 85-100% of the PAEC, is well defined and centred at about 100 nm in diameter. The minor mode, comprising the balance of the PAEC, varies in location from below 5 nm to about 10 nm. The particle size of the minor mode appears to correlate to the 'age' of the /sup 218/Po. The impactor tests conducted showed that < 16% of the PAEC resides on particles > 0.6 ..mu..m in diameter.

  9. Idealization Second Quantization of Composite Particles

    Institute of Scientific and Technical Information of China (English)

    ZHOU Duan-Lu; YU Si-Xia; SUN Chang-Pu

    2001-01-01

    A practical method is developed to deal with the second quantization of the many-body system containing the composite particles.In our treatment,the modes associated with composite particles are regarded approximately as independent ones compared with those of unbound particles.The field operators of the composite particles thus arise naturally in the second quantization Hamiltonian.To be emphasized,the second quantization Hamiltonian has the regular structures which correspond clearly to different physical processes.``

  10. New Edge Coherent Mode Providing Continuous Transport in Long Pulse H-mode Plasmas

    DEFF Research Database (Denmark)

    Wang, H.Q.; Xu, G.S.; Wan, B.N.

    2014-01-01

    An electrostatic coherent mode near the electron diamagnetic frequency (20–90 kHz) is observed in the steep-gradient pedestal region of long pulse H-mode plasmas in the Experimental Advanced Super-conducting Tokamak, using a newly developed dual gas-puff-imaging system and diamond-coated reciproc......An electrostatic coherent mode near the electron diamagnetic frequency (20–90 kHz) is observed in the steep-gradient pedestal region of long pulse H-mode plasmas in the Experimental Advanced Super-conducting Tokamak, using a newly developed dual gas-puff-imaging system and diamond......-coated reciprocating probes. The mode propagates in the electron diamagnetic direction in the plasma frame with poloidal wavelength of ∼8 cm. The mode drives a significant outflow of particles and heat as measured directly with the probes, thus greatly facilitating long pulse H-mode sustainment. This mode shows...

  11. Ambient measurements of biological aerosol particles near Killarney, Ireland: a comparison between real-time fluorescence and microscopy techniques

    Science.gov (United States)

    Healy, D. A.; Huffman, J. A.; O'Connor, D. J.; Pöhlker, C.; Pöschl, U.; Sodeau, J. R.

    2014-08-01

    Primary biological aerosol particles (PBAPs) can contribute significantly to the coarse particle burden in many environments. PBAPs can thus influence climate and precipitation systems as cloud nuclei and can spread disease to humans, animals, and plants. Measurement data and techniques for PBAPs in natural environments at high time- and size resolution are, however, sparse, and so large uncertainties remain in the role that biological particles play in the Earth system. In this study two commercial real-time fluorescence particle sensors and a Sporewatch single-stage particle impactor were operated continuously from 2 August to 2 September 2010 at a rural sampling location in Killarney National Park in southwestern Ireland. A cascade impactor was operated periodically to collect size-resolved particles during exemplary periods. Here we report the first ambient comparison of a waveband integrated bioaerosol sensor (WIBS-4) with a ultraviolet aerodynamic particle sizer (UV-APS) and also compare these real-time fluorescence techniques with results of fluorescence and optical microscopy of impacted samples. Both real-time instruments showed qualitatively similar behavior, with increased fluorescent bioparticle concentrations at night, when relative humidity was highest and temperature was lowest. The fluorescent particle number from the FL3 channel of the WIBS-4 and from the UV-APS were strongly correlated and dominated by a 3 μm mode in the particle size distribution. The WIBS FL2 channel exhibited particle modes at approx. 1 and 3 μm, and each was correlated with the concentration of fungal spores commonly observed in air samples collected at the site (ascospores, basidiospores, Ganoderma spp.). The WIBS FL1 channel exhibited variable multimodal distributions turning into a broad featureless single mode after averaging, and exhibited poor correlation with fungal spore concentrations, which may be due to the detection of bacterial and non-biological fluorescent

  12. Ambient measurements of biological aerosol particles near Killarney, Ireland: a comparison between real-time fluorescence and microscopy techniques

    Directory of Open Access Journals (Sweden)

    D. A. Healy

    2014-02-01

    Full Text Available Primary biological aerosol particles (PBAP can contribute significantly to the coarse particle burden in many environments, may thus influence climate and precipitation systems as cloud nuclei, and can spread disease to humans, animals, and plants. Measurements of PBAP in natural environments taken at high time- and size- resolution are, however, sparse and so large uncertainties remain in the role that biological particles play in the Earth system. In this study two commercial real-time fluorescence particle sensors and a Sporewatch single-stage particle impactor were operated continuously from 2 August to 2 September 2010 at a rural sampling location in Killarney National Park in south western Ireland. A cascade impactor was operated periodically to collect size-resolved particles during exemplary periods. Here we report the first ambient comparison of the waveband integrated bioaerosol sensor (WIBS-4 with the ultraviolet aerodynamic particle sizer (UV-APS and also compare these real-time fluorescence techniques with results of fluorescence and optical microscopy of impacted samples. Both real-time instruments showed qualitatively similar behaviour, with increased fluorescent bioparticle concentrations at night when relative humidity was highest and temperature was lowest. The fluorescent particle number from the FL3 channel of the WIBS-4 and from the UV-APS were strongly correlated and dominated by a 3 μm mode in the particle size distribution. The WIBS FL2 channel exhibited particle modes at approx. 1 and 3 μm, and each were correlated with the concentration of fungal spores commonly observed in air samples collected at the site (ascospores, basidiospores, Ganoderma spp.. The WIBS FL1 channel exhibited variable multi-modal distributions turning into a broad featureless single mode after averaging and exhibited poor correlation with fungal spore concentrations, which may be due to the detection of bacterial and non-biological fluorescent

  13. 3-d resistive MHD simulations of magnetic reconnection and the tearing mode instability in current sheets

    CERN Document Server

    Murphy, G C; Pelletier, Guy

    2008-01-01

    Magnetic reconnection plays a critical role in many astrophysical processes where high energy emission is observed, e.g. particle acceleration, relativistic accretion powered outflows, pulsar winds and probably in dissipation of Poynting flux in GRBs. The magnetic field acts as a reservoir of energy and can dissipate its energy to thermal and kinetic energy via the tearing mode instability. We have performed 3d nonlinear MHD simulations of the tearing mode instability in a current sheet. Results from a temporal stability analysis in both the linear regime and weakly nonlinear (Rutherford) regime are compared to the numerical simulations. We observe magnetic island formation, island merging and oscillation once the instability has saturated. The growth in the linear regime is exponential in agreement with linear theory. In the second, Rutherford regime the island width grows linearly with time. We find that thermal energy produced in the current sheet strongly dominates the kinetic energy. Finally preliminary ...

  14. New particle dependant parameterizations of heterogeneous freezing processes.

    Science.gov (United States)

    Diehl, Karoline; Mitra, Subir K.

    2014-05-01

    as illite or montmorillonite. Coupled cases of deposition and contact freezing show that they are hardly in competition because of differences in the preferred particle sizes. In the contact mode, small particles are less efficient for collisions as well as less efficient as ice nuclei so that these are available for deposition freezing. On the other hand, immersion freezing is the dominant process when it is coupled with deposition freezing. As it is initiated earlier the formed ice particles consume water vapor for growing. The competition of combined contact and immersion freezing leads to lower ice water contents because more ice particles are formed via the immersion mode. In general, ice clouds and mixed-phase clouds with high ice water fractions are not directly the result of primary ice formation but of secondary ice formation and growth of ice particles at the expense of liquid drops.

  15. A New Method to Assess Eye Dominance

    Science.gov (United States)

    Valle-Inclan, Fernando; Blanco, Manuel J.; Soto, David; Leiros, Luz

    2008-01-01

    People usually show a stable preference for one of their eyes when monocular viewing is required ("sighting dominance") or under dichoptic stimulation conditions ("sensory eye-dominance"). Current procedures to assess this "eye dominance" are prone to error. Here we present a new method that provides a continuous measure of eye dominance and…

  16. Mode analysis of numerical geodynamo models

    CERN Document Server

    Schrinner, Martin; Hoyng, Peter

    2011-01-01

    It has been suggested in Hoyng (2009) that dynamo action can be analysed by expansion of the magnetic field into dynamo modes and statistical evaluation of the mode coefficients. We here validate this method by analysing a numerical geodynamo model and comparing the numerically derived mean mode coefficients with the theoretical predictions. The model belongs to the class of kinematically stable dynamos with a dominating axisymmetric, antisymmetric with respect to the equator and non-periodic fundamental dynamo mode. The analysis requires a number of steps: the computation of the so-called dynamo coefficients, the derivation of the temporally and azimuthally averaged dynamo eigenmodes and the decomposition of the magnetic field of the numerical geodynamo model into the eigenmodes. For the determination of the theoretical mode excitation levels the turbulent velocity field needs to be projected on the dynamo eigenmodes. We compare the theoretically and numerically derived mean mode coefficients and find reason...

  17. CMB Anisotropies from a Gradient Mode

    CERN Document Server

    Mirbabayi, Mehrdad

    2014-01-01

    A pure gradient mode must have no observable dynamical effect at linear level. We confirm this by showing that its contribution to the dipolar power asymmetry of CMB anisotropies vanishes, if Maldacena's consistency condition is satisfied. To this end, the existing second order Sachs-Wolfe formula in the squeezed limit is extended to include a gradient in the long mode and to account for the change in the location of the last scattering surface induced by this mode. At second order, a gradient mode generated in Single-field inflation is shown to induce a quadrupole moment. For instance in a matter-dominated model it is equal to 5/18 times the square of the linear gradient part. This quadrupole can be cancelled by superposing a quadratic perturbation. The result is shown to be a non-linear extension of Weinberg's adiabatic modes: a long-wavelength physical mode which looks locally like a coordinate transformation.

  18. Dominant perceptions on the age

    Directory of Open Access Journals (Sweden)

    Komatina Slavica

    2003-01-01

    Full Text Available Contemporary developed society, despite the fact that it is constantly and intensively ageing, is characterized by deeply rooted numerous negative stereotypes on old people and old age as a life period. The study of dominant perceptions on the age of Belgrade population takes not only the universal character of negative connotation of old age into consideration, but also the concrete unfavorable social context. The delicate problematic of stereotypes on old age and old people has been analyzed mostly indirectly, through questions on the beginning of old age, advantages and difficulties which we experience during ageing, the first subjective conscious encounter with one’s own ageing, the concept of ideal old age, changes in the persons traits and directly through questions on dominant negative perceptions which prevail on old people in our surrounding. Ageing in the Belgrade milieu is most commonly identified with illness and with the decline of physical potentials, and at the same time a number of other negative qualifications of old age as well. Research results indicate to a pronounced ambivalent standpoint towards ageing, to different observation of one’s own to old age of other people, to different consideration of old age among the sexes and to obvious aversion towards old people. This is expected, taking into consideration that living and ageing are developing nowadays under aggressive influence of contemporary mass culture which affirms youth, beauty, physical strength, health as dominant values, namely everything that is contrary to ageing and old age. On the other hand, our society is today confronted with, as well as in the near past, exceptional political, economic and cultural difficulties which cause specific problems with various age groups, as well as the lowering of the level of mutual endurance and tolerance. The atmosphere of straining the old people and emergence of new antagonisms causes the intensification of

  19. High Intensity Particle Physics at PW-class laser facilities

    Science.gov (United States)

    Bulanov, Stepan; Schroeder, Carl; Esarey, Eric; Esirkepov, Timur; Kando, Masaki; Rosanov, Nikolay; Korn, Georg; Bulanov, Sergey V.; Leemans, Wim P.

    2015-11-01

    The processes typical for high intensity particle physics, i.e., the interactions of charged particles with strong electromagnetic fields, have attracted considerable interest recently. Some of these processes, previously believed to be of theoretical interest only, are now becoming experimentally accessible. High intensity electromagnetic (EM) fields significantly modify the interactions of particles and EM fields, giving rise to the phenomena that are not encountered either in classical or perturbative quantum theory of these interactions. One of such phenomena is the radiation reaction, which radically influences the electron motion in an electromagnetic standing wave formed by two super-intense counter-propagating laser pulses. Depending on the laser intensity and wavelength, either classical or quantum mode of radiation reaction prevail, or both are strong. When radiation reaction dominates, electron motion evolves to limit cycles and strange attractors. This creates a new framework for high energy physics experiments on an interaction of energetic charged particle beams and colliding super-intense laser pulses. Work supported by U.S. DOE under Contract No. DE-AC02-05CH11231.

  20. Ultrafine particles

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Weschler, Charles J.; Wierzbicka, Aneta;

    2013-01-01

    Particle number (PN) concentrations (10-300 nm in size) were continuously measured over a period of ∼45 h in 56 residences of nonsmokers in Copenhagen, Denmark. The highest concentrations were measured when occupants were present and awake (geometric mean, GM: 22.3 × 103 cm-3), the lowest when...... the homes were vacant (GM: 6.1 × 103 cm-3) or the occupants were asleep (GM: 5.1 × 103 cm-3). Diary entries regarding occupancy and particle related activities were used to identify source events and apportion the daily integrated exposure among sources. Source events clearly resulted in increased PN...... concentrations and decreased average particle diameter. For a given event, elevated particle concentrations persisted for several hours after the emission of fresh particles ceased. The residential daily integrated PN exposure in the 56 homes ranged between 37 × 103 and 6.0 × 106 particles per cm3·h/day (GM: 3...

  1. Particle therapy

    Energy Technology Data Exchange (ETDEWEB)

    Raju, M.R.

    1993-09-01

    Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics.

  2. Entropically Dominant State of Proteins

    CERN Document Server

    Li, Wenzhao; Tian, Suyan; Tian, Pu

    2012-01-01

    Configurational entropy is an important factor in the free energy change of many macromolecular recognition and binding processes, and has been intensively studied. Despite great progresses that have been made, the global sampling remains to be a grand challenge in computational analysis of relevant processes. Here we propose and demonstrate an entropy estimation method that is based on physical partition of configurational space and can be readily combined with currently available methodologies. Tests with two globular proteins suggest that for flexible macromolecules with large and complex configurational space, accurate configurational entropy estimation may be achieved simply by considering the entropically most important subspace. This conclusion effectively converts an exhaustive sampling problem into a local sampling one, and defines entropically dominant state for proteins and other complex macromolecules. The conceptional breakthrough is likely to positively impact future theoretical analysis, comput...

  3. Simulation of inverter dominated minigrids

    Energy Technology Data Exchange (ETDEWEB)

    Engler, A.; Osika, O. [Inst. fuer Solare Energieversorgungstechnik (ISET) e.V., Kassel (Germany)

    2003-07-01

    In order to assess the load flow, the transient behaviour and the stability of inverter dominated minigrids, a model for inverters and a transmission system has been developed. The inverters are represented by a frequency and voltage controlled three phase voltage source and the transmission systems consists of switches, overhead lines ({pi}-equivalent), transformers and a load. The inverters operate in parallel via the MV-distribution system and supply an active load. The contribution of each inverter is determined by the setting of the applied droops (similar to conventional power plants). Furthermore an approach for stability assessment of such systems is introduced. This research work is related to the EC-funded project MicroGrids. (orig.)

  4. A Note on Almost Stochastic Dominance

    OpenAIRE

    Guo, Xu; Zhu, Xuehu; Wong, Wing-Keung; Zhu, Lixing

    2013-01-01

    To satisfy the property of expected-utility maximization, Tzeng et al. (2012) modify the almost second-degree stochastic dominance proposed by Leshno and Levy (2002) and define almost higher-degree stochastic dominance. In this note, we further investigate the relevant properties. We define an almost third-degree stochastic dominance in the same way that Leshno and Levy (2002) define second-degree stochastic dominance and show that Leshno and Levy's (2002) almost stochastic dominance has t...

  5. Triboluminescence dominated by crystallographic orientation

    Science.gov (United States)

    Wang, Kuifang; Ma, Liran; Xu, Xuefeng; Wen, Shizhu; Luo, Jianbin

    2016-05-01

    Triboluminescence (TL) is an optical phenomenon that has a long and varied history with broad applications, such as damage detection, X-ray source, and mass health monitoring sensor. So far, the properties and mechanisms of TL remain not completely understood. The TL properties emitted during the sliding contact between Al2O3 and SiO2 surfaces were studied along different crystallographic orientations. In this study, the TL intensity of Al2O3 was significantly enhanced as Al2O3 surface was along a particular crystallographic orientation, which is an unconventional phenomenon. TL enhancement of Al2O3 was not affected by air atmosphere and atomic stocking mode of Al2O3. The enhancement mechanism of Al2O3 may be influenced by the surface state of Al2O3. This work provides a new method to control the intensity of TL and novel ideas to elucidate the TL mechanism.

  6. In-cloud sulfate addition to single particles resolved with sulfur isotope analysis during HCCT-2010

    Directory of Open Access Journals (Sweden)

    E. Harris

    2014-01-01

    Full Text Available In-cloud production of sulfate modifies the aerosol size distribution, with important implications for the magnitude of indirect and direct aerosol cooling and the impact of SO2 emissions on the environment. We investigate which sulfate sources dominate the in-cloud addition of sulfate to different particle classes as an air parcel passes through an orographic cloud. Sulfate aerosol, SO2 and H2SO4 were collected upwind, in-cloud and downwind of an orographic cloud for three cloud measurement events during the Hill Cap Cloud Thuringia campaign in Autumn, 2010 (HCCT-2010. Combined SEM and NanoSIMS analysis of single particles allowed the δ34S of particulate sulfate to be resolved for particle size and type. The most important in-cloud SO2 oxidation pathway at HCCT-2010 was aqueous oxidation catalysed by transition metal ions (TMI catalysis, which was shown with single particle isotope analyses to occur primarily in cloud droplets nucleated on coarse mineral dust. In contrast, direct uptake of H2SO4(g and ultrafine particulate were the most important sources modifying fine mineral dust, increasing its hygroscopicity and facilitating activation. Sulfate addition to "mixed" particles (secondary organic and inorganic aerosol and coated soot was dominated by in-cloud aqueous SO2 oxidation by H2O2 and direct uptake of H2SO4(g and ultrafine particle sulfate, depending on particle size mode and time of day. These results provide new insight into in-cloud sulfate production mechanisms, and show the importance of single particle measurements and models to accurately assess the environmental effects of cloud processing.

  7. Particle Physics

    CERN Document Server

    Martin, B R

    2008-01-01

    An essential introduction to particle physics, with coverage ranging from the basics through to the very latest developments, in an accessible and carefully structured text. Particle Physics: Third Edition is a revision of a highly regarded introduction to particle physics. In its two previous editions this book has proved to be an accessible and balanced introduction to modern particle physics, suitable for those students needed a more comprehensive introduction to the subject than provided by the 'compendium' style physics books. In the Third Edition the standard mod

  8. Edge energy transport barrier and turbulence in the I-mode regime on Alcator C-Moda)

    Science.gov (United States)

    Hubbard, A. E.; Whyte, D. G.; Churchill, R. M.; Cziegler, I.; Dominguez, A.; Golfinopoulos, T.; Hughes, J. W.; Rice, J. E.; Bespamyatnov, I.; Greenwald, M. J.; Howard, N.; Lipschultz, B.; Marmar, E. S.; Reinke, M. L.; Rowan, W. L.; Terry, J. L.

    2011-05-01

    We report extended studies of the I-mode regime [Whyte et al., Nucl. Fusion 50, 105005 (2010)] obtained in the Alcator C-Mod tokamak [Marmar et al., Fusion Sci. Technol. 51(3), 3261 (2007)]. This regime, usually accessed with unfavorable ion B × ∇B drift, features an edge thermal transport barrier without a strong particle transport barrier. Steady I-modes have now been obtained with favorable B × ∇B drift, by using specific plasma shapes, as well as with unfavorable drift over a wider range of shapes and plasma parameters. With favorable drift, power thresholds are close to the standard scaling for L-H transitions, while with unfavorable drift they are ˜ 1.5-3 times higher, increasing with Ip. Global energy confinement in both drift configurations is comparable to H-mode scalings, while density profiles and impurity confinement are close to those in L-mode. Transport analysis of the edge region shows a decrease in edge χeff, by typically a factor of 3, between L- and I-mode. The decrease correlates with a drop in mid-frequency fluctuations (f ˜ 50-150 kHz) observed on both density and magnetics diagnostics. Edge fluctuations at higher frequencies often increase above L-mode levels, peaking at f ˜ 250 kHz. This weakly coherent mode is clearest and has narrowest width (Δf/f ˜ 0.45) at low q95 and high Tped, up to 1 keV. The Er well in I-mode is intermediate between L- and H-mode and is dominated by the diamagnetic contribution in the impurity radial force balance, without the Vpol shear typical of H-modes.

  9. Global mode analysis of ideal MHD modes in a heliotron/torsatron system. 1. Mercier-unstable equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.; Nakajima, N.; Okamoto, M.

    1998-12-01

    By means of a global mode analysis of ideal MHD modes for Mercier-unstable equilibria in a planar axis L=2/M=10 heliotron/torsatron system with an inherently large Shafranov shift, the conjecture from local mode analysis for Mercier-unstable equilibria given in [N. Nakajima, Phys. Plasmas 3, 4556 (1996)] has been confirmed and the properties of pressure-driven modes, namely, ballooning modes and interchange modes, inherent to such three-dimensional systems have been clarified. The change of the local magnetic shear due to the Shafranov shift, which is related to toroidicity, reduces the field line bending stabilizing effects on ballooning modes. According to the degree of the reduction of the local magnetic shear by the Shafranov shift, the Mercier-unstable equilibria are categorized into toroidicity-dominant (strong reduction) and helicity-dominant (weak reduction) Mercier-unstable equilibria. Since the local magnetic curvature due to helicity has the same period M in the toroidal direction as the toroidal field period of the equilibria, the characteristics of the pressure-driven modes in such Mercier-unstable equilibria dramatically change, both according to the reduction of the local magnetic shear by the Shafranov shift and also according to the relative magnitude of the typical toroidal mode number n of the perturbation compared with the toroidal field period of the equilibria M. In the toroidicity-dominant Mercier-unstable equilibria, the pressure-driven modes change from interchange modes for low toroidal mode numbers n < M, to tokamak-like poloidally localized ballooning modes with a weak toroidal mode coupling for moderate toroidal mode numbers n - M, and finally to both poloidally and toroidally localized ballooning modes purely inherent to three-dimensional systems for fairly high toroidal mode numbers n >> M. In the helicity-dominant Mercier-unstable equilibria, the pressure-driven modes change from interchange modes for n < M or n - M, directly to both

  10. Exhaust particle and NOx emission performance of an SCR heavy duty truck operating in real-world conditions

    Science.gov (United States)

    Saari, Sampo; Karjalainen, Panu; Ntziachristos, Leonidas; Pirjola, Liisa; Matilainen, Pekka; Keskinen, Jorma; Rönkkö, Topi

    2016-02-01

    Particle and NOx emissions of an SCR equipped HDD truck were studied in real-world driving conditions using the "Sniffer" mobile laboratory. Real-time CO2 measurement enables emission factor calculation for NOx and particles. In this study, we compared three different emission factor calculation methods and characterised their suitability for real-world chasing experiments. The particle number emission was bimodal and dominated by the nucleation mode particles (diameter below 23 nm) having emission factor up to 1 × 1015 #/kgfuel whereas emission factor for soot (diameter above 23 nm that is consistent with the PMP standard) was typically 1 × 1014 #/kgfuel. The effect of thermodenuder on the exhaust particles indicated that the nucleation particles consisted mainly of volatile compounds, but sometimes there also existed a non-volatile core. The nucleation mode particles are not controlled by current regulations in Europe. However, these particles consistently form under atmospheric dilution in the plume of the truck and constitute a health risk for the human population that is exposed to those. Average NOx emission was 3.55 g/kWh during the test, whereas the Euro IV emission limit over transient testing is 3.5 g NOx/kWh. The on-road emission performance of the vehicle was very close to the expected levels, confirming the successful operation of the SCR system of the tested vehicle. Heavy driving conditions such as uphill driving increased both the NOx and particle number emission factors whereas the emission factor for soot particle number remains rather constant.

  11. Influence of the operating modes of wood-fired stoves on particle emissions; Einfluss der Betriebsweise auf die Partikelemissionen von Holzoefen. Projektzusatz 1+2 zum Projekt Wirkung von Verbrennungspartikeln

    Energy Technology Data Exchange (ETDEWEB)

    Klippel, N.; Nussbaumer, T.

    2007-03-15

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) examines the influence of the operating characteristics of wood-fired stoves on their particle emissions. Four types of stove are compared: A metal stove with small combustion chamber and a low mass of ceramic lining, a stove with a large combustion chamber and heavier ceramic lining, a newly designed stove with two-stage combustion using gasification and gas oxidation in a separate combustion chamber using secondary air and a modern pellet-fired stove operated with wood and straw pellets. The report describes the measurement programme and presents the results obtained using gravimetric measurements. The spectrum of particle emissions measured for the four types of stove are presented and discussed. The correlation of carbon monoxide and fine-dust emissions is examined. The results of biological tests and the chemical analysis of the dust are discussed.

  12. FINE AND COARSE PARTICLES: CONCENTRATION RELATIONSHIPS RELEVANT TO EPIDEMIOLOGICAL STUDIES

    Science.gov (United States)

    Fine particles and coarse particles are defined in terms of the modal structure of particle size distributions typically observed in the atmosphere. Differences among the various modes are discussed. The fractions of fine and coarse particles collected in specific size ranges, ...

  13. Transition from avalanche dominated transport to drift-wave dominated transport in a basic laboratory experiment

    Science.gov (United States)

    van Compernolle, Bart; Morales, George; Maggs, James; Sydora, Richard

    2016-10-01

    Results of a basic heat transport experiment involving an off-axis heat source are presented. Experiments are performed in the Large Plasma Device (LAPD) at UCLA. A ring-shaped electron beam source injects low energy electrons (below ionization energy) along a strong magnetic field into a preexisting, large and cold plasma. The injected electrons are thermalized by Coulomb collisions within a short distance and provide an off-axis heat source that results in a long, hollow, cylindrical region of elevated plasma pressure embedded in a colder plasma, and far from the machine walls. The off-axis source is active for a period long compared to the density decay time, i.e. as time progresses the power per particle increases. Two distinct regimes are observed to take place, an initial regime dominated by avalanches, identified as sudden intermittent rearrangements of the pressure profile, and a second regime dominated by sustained drift-Alfvén wave activity. The transition between the two regimes is sudden, affects the full radial profile and is preceded by the growth of drift Alfvén waves. Langmuir probe data will be shown on the evolution of the density, temperature and flow profiles during the transition. The character of the sustained drift wave activity will also be presented. Work supported by NSF/DOE Grant 1619505, and performed at the Basic Plasma Science Facility, sponsored jointly by DOE and NSF.

  14. Voltage Mode-to-Current Mode Transformation

    Directory of Open Access Journals (Sweden)

    Tejmal S. Rathore

    2012-10-01

    Full Text Available This paper proposes a procedure for converting a class of Op Amp-, FTFN-, CC- and CFAbased voltage mode circuits to corresponding current mode circuits without requiring any additional circuit elements and finally from Op Amp-based voltage mode circuits to any of the FTFN, CC and CFA current mode circuits. The latter circuits perform better at high frequency than the former ones. The validity of the transformation has been checked on simulated circuits with PSPICE.

  15. Biological aerosol particle concentrations and size distributions measured in pristine tropical rainforest air during AMAZE-08

    Science.gov (United States)

    Huffman, J. A.; Sinha, B.; Garland, R. M.; Snee-Pollmann, A.; Gunthe, S. S.; Artaxo, P.; Martin, S. T.; Andreae, M. O.; Pöschl, U.

    2012-09-01

    As a part of the AMAZE-08 campaign during the wet season in the rainforest of Central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS) was operated for continuous measurements of fluorescent biological aerosol particles (FBAP). In the coarse particle size range (> 1 μm) the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m-3 (4.0-13.2 × 104 m-3) and 0.72 μg m-3 (0.42-1.19 μg mm-3), respectively, accounting for 24% (11-41%) of total particle number and 47% (25-65%) of total particle mass. During the five-week campaign in February-March 2008 the concentration of coarse-mode Saharan dust particles was highly variable. In contrast, FBAP concentrations remained fairly constant over the course of weeks and had a consistent daily pattern, peaking several hours before sunrise, suggesting observed FBAP was dominated by nocturnal spore emission. This conclusion was supported by the consistent FBAP number size distribution peaking at 2.3 μm, also attributed to fungal spores and mixed biological particles by scanning electron microscopy (SEM), light microscopy and biochemical staining. A second primary biological aerosol particle (PBAP) mode between 0.5 and 1.0 μm was also observed by SEM, but exhibited little fluorescence and no fungal staining. This mode consisted of single bacterial cells, brochosomes and various fragments of biological material. Particles liquid-coated with mixed organic-inorganic material constituted a large fraction of observations, and these coatings contained salts likely from primary biological origin. We provide key support for the suggestion that real-time laser-induce fluorescence (LIF) techniques provide size-resolved concentrations of FBAP as a lower limit for the atmospheric abundance of biological particles. We also show that primary biological particles, fungal spores in particular, are key fractions of supermicron aerosol in the Amazon and that, especially when coated by mixed inorganic

  16. Biological aerosol particle concentrations and size distributions measured in pristine tropical rainforest air during AMAZE-08

    Directory of Open Access Journals (Sweden)

    J. A. Huffman

    2012-09-01

    Full Text Available As a part of the AMAZE-08 campaign during the wet season in the rainforest of Central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS was operated for continuous measurements of fluorescent biological aerosol particles (FBAP. In the coarse particle size range (> 1 μm the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m−3 (4.0–13.2 × 104 m−3 and 0.72 μg m−3 (0.42–1.19 μg mm−3, respectively, accounting for 24% (11–41% of total particle number and 47% (25–65% of total particle mass. During the five-week campaign in February–March 2008 the concentration of coarse-mode Saharan dust particles was highly variable. In contrast, FBAP concentrations remained fairly constant over the course of weeks and had a consistent daily pattern, peaking several hours before sunrise, suggesting observed FBAP was dominated by nocturnal spore emission. This conclusion was supported by the consistent FBAP number size distribution peaking at 2.3 μm, also attributed to fungal spores and mixed biological particles by scanning electron microscopy (SEM, light microscopy and biochemical staining. A second primary biological aerosol particle (PBAP mode between 0.5 and 1.0 μm was also observed by SEM, but exhibited little fluorescence and no fungal staining. This mode consisted of single bacterial cells, brochosomes and various fragments of biological material. Particles liquid-coated with mixed organic-inorganic material constituted a large fraction of observations, and these coatings contained salts likely from primary biological origin. We provide key support for the suggestion that real-time laser-induce fluorescence (LIF techniques provide size-resolved concentrations of FBAP as a lower limit for the atmospheric abundance of biological particles. We also show that primary biological particles, fungal spores in particular, are key

  17. MODE I AND MODE II CRACK TIP ASYMPTOTIC FIELDS WITH STRAIN GRADIENT EFFECTS

    Institute of Scientific and Technical Information of China (English)

    陈少华; 王自强

    2001-01-01

    The strain gradient effect becomes significant when the size of fracture process zone around a crack tip is comparable to the intrinsic material length l,typically of the order of microns. Using the new strain gradient deformation theory given by Chen and Wang, the asymptotic fields near a crack tip in an elastic-plastic material with strain gradient effects are investigated. It is established that the dominant strain field is irrotational. For mode I plane stress crack tip asymptotic field,the stress asymptotic field and the couple stress asymptotic field can not exist simultaneously. In the stress dominated asymptotic field, the angular distributions of stresses are consistent with the classical plane stress HRR field; In the couple stress dominated asymptotic field, the angular distributions of couple stresses are consistent with that obtained by Huang et al. For mode II plane stress and plane strain crack tip asymptotic fields, only the stress-dominated asymptotic fields exist. The couple stress asymptotic field is less singular than the stress asymptotic fields. The stress asymptotic fields are the same as mode II plane stress and plane strain HRR fields,respectively. The increase in stresses is not observed in strain gradient plasticity for mode I and mode II, because the present theory is based only on the rotational gradient of deformation and the crack tip asymptotic fields are irrotational and dominated by the stretching gradient.

  18. CMB anisotropies from a gradient mode

    Science.gov (United States)

    Mirbabayi, Mehrdad; Zaldarriaga, Matias

    2015-03-01

    A linear gradient mode must have no observable dynamical effect on short distance physics. We confirm this by showing that if there was such a gradient mode extending across the whole observable Universe, it would not cause any hemispherical asymmetry in the power of CMB anisotropies, as long as Maldacena's consistency condition is satisfied. To study the effect of the long wavelength mode on short wavelength modes, we generalize the existing second order Sachs-Wolfe formula in the squeezed limit to include a gradient in the long mode and to account for the change in the location of the last scattering surface induced by this mode. Next, we consider effects that are of second order in the long mode. A gradient mode Φ = qṡx generated in Single-field inflation is shown to induce an observable quadrupole moment. For instance, in a matter-dominated model it is equal to Q = 5(qṡx)2/18. This quadrupole can be canceled by superposition of a quadratic perturbation. The result is shown to be a nonlinear extension of Weinberg's adiabatic modes: a long-wavelength physical mode which looks locally like a coordinate transformation.

  19. General N-th Degree Stochastic Dominance

    Institute of Scientific and Technical Information of China (English)

    张顺明

    2001-01-01

    This paper examines N-th degree stochastic dominance which isused to compare the risk factor of risky assets after summarizing the definitions of first degree stochastic dominance and second degree stochastic dominance. The paper defines general N-th degree stochastic dominance, presents a sufficient and necessary condition which is the equivalent theorem of general N-th degree stochastic dominance. The feasible utility form is constructed to explain the economic meaning of N-th degree stochastic dominance in the field of financial economics. The equivalent condition is described by the probability distribution functions of risky assets, which are not related to utility functions (preference relations).

  20. Electrooptical Detection of Charged Particles

    CERN Document Server

    Semertzidis, Y K; Kowalski, L A; Kraus, D E; Larsen, R; Lazarus, D M; Magurno, B; Nikas, D; Ozben, C; Srinivasan-Rao, T; Tsang, Thomas

    2000-01-01

    We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO3 crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds promise for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

  1. Effect of fluid motion on the impact erosion by a micro-particle on quartz crystals

    Science.gov (United States)

    Cai, D. H.; Qi, H.; Wen, D. H.; Zhang, L.; Yuan, Q. L.; Chen, Z. Z.

    2016-08-01

    Abrasive slurry jet (ASJ) is a promising technology to process a variety of materials with advantages of high flexibility, no heat affected zone and high cutting efficiency. In this paper, the impressions generated on a quartz crystal specimen by the impacts of micro-particles laden in a water flow and the associated impact erosion mechanisms are presented and discussed in order to effectively and efficiently control the machining quality. Both brittle and ductile mode erosions coexist in the machining process due to the influence of the fluid motion on the trajectories of particles near the target surface. Large-scale craters produced by brittle conchoidal fractures associated with crashed zone, radial and lateral cracks, dominate the erosion process at large jet impact angles while small-scale craters involving micro-ploughing and micro-cutting are produced by the ductile mode erosion at small jet impact angles. The relation between the process parameters and the overall average volume of craters has also been quantitatively analyzed. A combination of small jet impact angle and abrasive particles and low water pressure is preferred for improving the surface quality after the ASJ machining process caused by the more formation of ductile mode induced craters on the target material, but it is at the sacrifice of the material removal rate as well.

  2. Effect of fluid motion on the impact erosion by a micro-particle on quartz crystals

    Directory of Open Access Journals (Sweden)

    D. H. Cai

    2016-08-01

    Full Text Available Abrasive slurry jet (ASJ is a promising technology to process a variety of materials with advantages of high flexibility, no heat affected zone and high cutting efficiency. In this paper, the impressions generated on a quartz crystal specimen by the impacts of micro-particles laden in a water flow and the associated impact erosion mechanisms are presented and discussed in order to effectively and efficiently control the machining quality. Both brittle and ductile mode erosions coexist in the machining process due to the influence of the fluid motion on the trajectories of particles near the target surface. Large-scale craters produced by brittle conchoidal fractures associated with crashed zone, radial and lateral cracks, dominate the erosion process at large jet impact angles while small-scale craters involving micro-ploughing and micro-cutting are produced by the ductile mode erosion at small jet impact angles. The relation between the process parameters and the overall average volume of craters has also been quantitatively analyzed. A combination of small jet impact angle and abrasive particles and low water pressure is preferred for improving the surface quality after the ASJ machining process caused by the more formation of ductile mode induced craters on the target material, but it is at the sacrifice of the material removal rate as well.

  3. IMM Iterated Extended Particle Filter Algorithm

    OpenAIRE

    Yang Wan; Shouyong Wang; Xing Qin

    2013-01-01

    In order to solve the tracking problem of radar maneuvering target in nonlinear system model and non-Gaussian noise background, this paper puts forward one interacting multiple model (IMM) iterated extended particle filter algorithm (IMM-IEHPF). The algorithm makes use of multiple modes to model the target motion form to track any maneuvering target and each mode uses iterated extended particle filter (IEHPF) to deal with the state estimation problem of nonlinear non-Gaussian system. IEH...

  4. [Sighting dominance in patients with macular disease].

    Science.gov (United States)

    Akaza, Eriko; Fujita, Kyoko; Shimada, Hiroyuki; Yuzawa, Mitsuko

    2007-04-01

    To study sighting dominance by comparing macular disease patients undergoing surgical treatment with controls. We studied visual acuity and sighting dominance in 92 macular disease patients, 27 of whom were assessed for both outcomes. We also studied visual acuity and sighting dominance in 412 controls. Sighting dominance was evaluated using the hole-in-card test. Among the controls, 70% showed right sighting dominance, and 30%, left sighting dominance. On the other hand, in patients with macular disease, right sighting dominance was demonstrated in 51%, and left in 49%; that is, 24% showed sighting dominance of the affected eye and 76%, of the fellow eye. During follow-up, sighting dominance of three of the 27 macular disease patients shifted from the affected eye to the fellow eye, which showed improvement in visual acuity. This study raises the possibility of sighting dominance shifting in patients with macular disease. There were differences among cases in the timing of the shift in sighting dominance, indicating that visual acuity may not be the only factor influencing sighting dominance. Further study is needed to confirm the factors contributing to sighting dominance.

  5. Quantification of environmentally persistent free radicals and reactive oxygen species in atmospheric aerosol particles

    Science.gov (United States)

    Arangio, Andrea M.; Tong, Haijie; Socorro, Joanna; Pöschl, Ulrich; Shiraiwa, Manabu

    2016-10-01

    Fine particulate matter plays a central role in the adverse health effects of air pollution. Inhalation and deposition of aerosol particles in the respiratory tract can lead to the release of reactive oxygen species (ROS), which may cause oxidative stress. In this study, we have detected and quantified a wide range of particle-associated radicals using electron paramagnetic resonance (EPR) spectroscopy. Ambient particle samples were collected using a cascade impactor at a semi-urban site in central Europe, Mainz, Germany, in May-June 2015. Concentrations of environmentally persistent free radicals (EPFR), most likely semiquinone radicals, were found to be in the range of (1-7) × 1011 spins µg-1 for particles in the accumulation mode, whereas coarse particles with a diameter larger than 1 µm did not contain substantial amounts of EPFR. Using a spin trapping technique followed by deconvolution of EPR spectra, we have also characterized and quantified ROS, including OH, superoxide (O2-) and carbon- and oxygen-centered organic radicals, which were formed upon extraction of the particle samples in water. Total ROS amounts of (0.1-3) × 1011 spins µg-1 were released by submicron particle samples and the relative contributions of OH, O2-, C-centered and O-centered organic radicals were ˜ 11-31, ˜ 2-8, ˜ 41-72 and ˜ 0-25 %, respectively, depending on particle sizes. OH was the dominant species for coarse particles. Based on comparisons of the EPR spectra of ambient particulate matter with those of mixtures of organic hydroperoxides, quinones and iron ions followed by chemical analysis using liquid chromatography mass spectrometry (LC-MS), we suggest that the particle-associated ROS were formed by decomposition of organic hydroperoxides interacting with transition metal ions and quinones contained in atmospheric humic-like substances (HULIS).

  6. Influence of vibration mode on the screening process

    Institute of Scientific and Technical Information of China (English)

    Dong Hailin; Liu Chusheng; Zhao Yuemin; Zhao Lala

    2013-01-01

    The screening of particles with different vibration modes was simulated by means of a 3D discrete element method (3D-DEM).The motion and penetration of the particles on the screen deck were analyzed for linear,circular and elliptical vibration of the screen.The results show that the travel velocity of the particles is the fastest,but the screening efficiency is the lowest,for the linear vibration mode.The circular motion resulted in the highest screening efficiency,but the lowest particle travel velocity.In the steady state the screening efficiency for each mode is seen to increase gradually along the longitudinal direction of the deck.The screening efficiency increment of the circular mode is the largest while the linear mode shows the smallest increment.The volume fraction of near-mesh size particles at the underside is larger than that of small size particles all along the screen deck.Linear screening mode has more nearmesh and small size particles on the first three deck sections,and fewer on the last two sections,compared to the circular or elliptical modes.

  7. The impact of heating the breakdown bubble on the global mode of a swirling jet: Experiments and linear stability analysis

    Science.gov (United States)

    Rukes, Lothar; Sieber, Moritz; Paschereit, C. Oliver; Oberleithner, Kilian

    2016-10-01

    This study investigates the dynamics of non-isothermal swirling jets undergoing vortex breakdown, with an emphasis on helical coherent structures. It is proposed that the dominant helical coherent structure can be suppressed by heating the recirculation bubble. This proposition is assessed with stereo Particle Image Velocimetry (PIV) measurements of the breakdown region of isothermal and heated swirling jets. The coherent kinetic energy of the dominant helical structure was derived from PIV snapshots via proper orthogonal decomposition. For one set of experimental parameters, mild heating is found to increase the energy content of the dominant helical mode. Strong heating leads to a reduction by 30% of the coherent structures energy. For a second set of experimental parameters, no alteration of the dominant coherent structure is detectable. Local linear stability analysis of the time-averaged velocity fields shows that the key difference between the two configurations is the density ratio at the respective wavemaker location. A density ratio of approximately 0.8 is found to correlate to a suppression of the global mode in the experiments. A parametric study with model density and velocity profiles indicates the most important parameters that govern the local absolute growth rate: the density ratio and the relative position of the density profiles and the inner shear layer.

  8. Inertial modes and their transition to turbulence in a differentially rotating spherical gap flow

    Science.gov (United States)

    Hoff, Michael; Harlander, Uwe; Andrés Triana, Santiago; Egbers, Christoph

    2016-04-01

    We present a study of inertial modes in a spherical shell experiment. Inertial modes are Coriolis-restored linear wave modes, often arise in rapidly-rotating fluids (e.g. in the Earth's liquid outer core [1]). Recent experimental works showed that inertial modes exist in differentially rotating spherical shells. A set of particular inertial modes, characterized by (l,m,ˆω), where l, m is the polar and azimuthal wavenumber and ˆω = ω/Ωout the dimensionless frequency [2], has been found. It is known that they arise due to eruptions in the Ekman boundary layer of the outer shell. But it is an open issue why only a few modes develop and how they get enhanced. Kelley et al. 2010 [3] showed that some modes draw their energy from detached shear layers (e.g. Stewartson layers) via over-reflection. Additionally, Rieutord et al. (2012) [4] found critical layers within the shear layers below which most of the modes cannot exist. In contrast to other spherical shell experiments, we have a full optical access to the flow. Therefore, we present an experimental study of inertial modes, based on Particle-Image-Velocimetry (PIV) data, in a differentially rotating spherical gap flow where the inner sphere is subrotating or counter-rotating at Ωin with respect to the outer spherical shell at Ωout, characterized by the Rossby number Ro = (Ωin - Ωout)/Ωout. The radius ratio of η = 1/3, with rin = 40mm and rout = 120mm, is close to that of the Earth's core. Our apparatus is running at Ekman numbers (E ≈ 10-5, with E = ν/(Ωoutrout2), two orders of magnitude higher than most of the other experiments. Based on a frequency-Rossby number spectrogram, we can partly confirm previous considerations with respect to the onset of inertial modes. In contrast, the behavior of the modes in the counter-rotation regime is different. We found a triad interaction between three dominant inertial modes, where one is a slow axisymmetric Rossby mode [5]. We show that the amplitude of the most

  9. Neural network sliding mode control based on improved particle swarm optimization algorithm for discrete-time chaotic systems%基于改进粒子群优化算法的离散混沌系统神经滑模控制

    Institute of Scientific and Technical Information of China (English)

    吴建辉; 章兢; 刘朝华

    2013-01-01

      Aiming at discrete-time chaotic systems, the neural network sliding mode equivalent control method based on a hybrid algorithm which combines the particle swarm optimization algorithm and the Powell search method(Powell-PSO algorithm) is proposed. When taking the output of BP neural network as the coefficient of the switch part of sliding mode equivalent control, the method effectively overcomes the chattering phenomenon of conventional sliding mode equivalent control. The Powell-PSO algorithm is applied to globally optimize the parameters of neural network sliding mode controller and then to control discrete-time chaotic systems more effectively. Simulation results show that the method requires no knowledge about the precise mathematical model of discrete-time chaotic systems with fast response speed, high control precision and strong anti-interference ability.%  针对离散混沌系统,提出一种基于融合Powell法的粒子群优化策略(Powell-PSO算法)的神经滑模等效控制方法。该方法通过将BP神经网络的输出作为滑模等效控制的切换部分的系数,有效地克服了传统滑模等效控制的抖振现象;利用Powell-PSO算法对神经滑模控制器的参数进行全局优化,提高了离散混沌系统的控制品质。仿真实验结果表明,所提出的方法无需了解离散混沌系统精确模型,具有响应速度快、控制精度高以及抗干扰能力强的优点。

  10. Outer-2-independent domination in graphs

    Indian Academy of Sciences (India)

    Marcin Krzywkowski; Doost Ali Mojdeh; Maryem Raoofi

    2016-02-01

    We initiate the study of outer-2-independent domination in graphs. An outer-2-independent dominating set of a graph is a set of vertices of such that every vertex of ()\\ has a neighbor in and the maximum vertex degree of the subgraph induced by ()\\ is at most one. The outer-2-independent domination number of a graph is the minimum cardinality of an outer-2-independent dominating set of . We show that if a graph has minimum degree at least two, then its outer-2-independent domination number equals the number of vertices minus the 2-independence number. Then we investigate the outer-2-independent domination in graphs with minimum degree one. We also prove the Vizing-type conjecture for outer-2-independent domination and disprove the Vizing-type conjecture for outer-connected domination.

  11. A case study of columnar marine and dust particle ratios calculated with photometric and lidar measurements during the CHARADMEXP campaign

    Science.gov (United States)

    Panagiotis Raptis, Ioannis; Kokkalis, Panagiotis; Amiridis, Vassilis; Taylor, Michael; Kazadzis, Stelios

    2015-04-01

    The CHARADMEXP campaign took place at the Finokalia meteorological station on the island of Crete, Greece from the 20th of June to 10th July 2014 deploying various instruments to monitor aerosol mixtures of dust and marine origin (more info at http://charadmexp.gr). In this study we focus on data recorded on 1st July. This day gain our interest because we had two distinguished layer of particles at different heights, sea salt near the ground and dust at planetary boundary layer height. A raman/depolarization lidar (EMORAL) and a CIMEL photometer were simultaneously operating during the time of interest in the area. Multimodal analysis of retrieved AERONET volume size distributions on that day was used to distinguish between dominant aerosol types and to calculate the percentage contribution of each mode to the columnar volume concentration. Selection of the method was based on previous work which showed that in cases of mixtures that contain sea salt, bi-lognormals fail to recover key features of the average size distribution. Linear particle depolarization ratio profiles were used to discriminate spherical from non-spherical particles and to validate the columnar volume percentage contribution of different types provided by multimodal analysis. We found that the column was dominated mainly by coarse mode aerosol of marine and dust origin in equal volume proportion in the morning hours. As the day progressed, dust concentrations declined and marine particles became dominant . Lidar profiles confirmed dual layering of particles. The aerosol load was found to be low (AOD≈0.1-0.2) and allowed for a test of the sensitivity of the multimodal method at small concentrations.

  12. Echo particle image velocimetry.

    Science.gov (United States)

    DeMarchi, Nicholas; White, Christopher

    2012-12-27

    The transport of mass, momentum, and energy in fluid flows is ultimately determined by spatiotemporal distributions of the fluid velocity field.(1) Consequently, a prerequisite for understanding, predicting, and controlling fluid flows is the capability to measure the velocity field with adequate spatial and temporal resolution.(2) For velocity measurements in optically opaque fluids or through optically opaque geometries, echo particle image velocimetry (EPIV) is an attractive diagnostic technique to generate "instantaneous" two-dimensional fields of velocity.(3,4,5,6) In this paper, the operating protocol for an EPIV system built by integrating a commercial medical ultrasound machine(7) with a PC running commercial particle image velocimetry (PIV) software(8) is described, and validation measurements in Hagen-Poiseuille (i.e., laminar pipe) flow are reported. For the EPIV measurements, a phased array probe connected to the medical ultrasound machine is used to generate a two-dimensional ultrasound image by pulsing the piezoelectric probe elements at different times. Each probe element transmits an ultrasound pulse into the fluid, and tracer particles in the fluid (either naturally occurring or seeded) reflect ultrasound echoes back to the probe where they are recorded. The amplitude of the reflected ultrasound waves and their time delay relative to transmission are used to create what is known as B-mode (brightness mode) two-dimensional ultrasound images. Specifically, the time delay is used to determine the position of the scatterer in the fluid and the amplitude is used to assign intensity to the scatterer. The time required to obtain a single B-mode image, t, is determined by the time it take to pulse all the elements of the phased array probe. For acquiring multiple B-mode images, the frame rate of the system in frames per second (fps) = 1/δt. (See 9 for a review of ultrasound imaging.) For a typical EPIV experiment, the frame rate is between 20-60 fps

  13. Photovoltaic failure and degradation modes: PV failure and degradation modes

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Dirk C. [National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway Golden Colorado 80401 USA; Silverman, Timothy J. [National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway Golden Colorado 80401 USA; Wohlgemuth, John H. [National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway Golden Colorado 80401 USA; Kurtz, Sarah R. [National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway Golden Colorado 80401 USA; VanSant, Kaitlyn T. [Colorado School of Mines, 1500 Illinois Street Golden Colorado 8040 USA

    2017-01-30

    The extensive photovoltaic field reliability literature was analyzed and reviewed. Future work is prioritized based upon information assembled from recent installations, and inconsistencies in degradation mode identification are discussed to help guide future publication on this subject. Reported failure rates of photovoltaic modules fall mostly in the range of other consumer products; however, the long expected useful life of modules may not allow for direct comparison. In general, degradation percentages are reported to decrease appreciably in newer installations that are deployed after the year 2000. However, these trends may be convoluted with varying manufacturing and installation quality world-wide. Modules in hot and humid climates show considerably higher degradation modes than those in desert and moderate climates, which warrants further investigation. Delamination and diode/j-box issues are also more frequent in hot and humid climates than in other climates. The highest concerns of systems installed in the last 10 years appear to be hot spots followed by internal circuitry discoloration. Encapsulant discoloration was the most common degradation mode, particularly in older systems. In newer systems, encapsulant discoloration appears in hotter climates, but to a lesser degree. Thin-film degradation modes are dominated by glass breakage and absorber corrosion, although the breadth of information for thin-film modules is much smaller than for x-Si.

  14. Chamber bioaerosol study: human emissions of size-resolved fluorescent biological aerosol particles.

    Science.gov (United States)

    Bhangar, S; Adams, R I; Pasut, W; Huffman, J A; Arens, E A; Taylor, J W; Bruns, T D; Nazaroff, W W

    2016-04-01

    Humans are a prominent source of airborne biological particles in occupied indoor spaces, but few studies have quantified human bioaerosol emissions. The chamber investigation reported here employs a fluorescence-based technique to evaluate bioaerosols with high temporal and particle size resolution. In a 75-m(3) chamber, occupant emission rates of coarse (2.5-10 μm) fluorescent biological aerosol particles (FBAPs) under seated, simulated office-work conditions averaged 0.9 ± 0.3 million particles per person-h. Walking was associated with a 5-6× increase in the emission rate. During both walking and sitting, 60-70% or more of emissions originated from the floor. The increase in emissions during walking (vs. while sitting) was mainly attributable to release of particles from the floor; the associated increased vigor of upper body movements also contributed. Clothing, or its frictional interaction with human skin, was demonstrated to be a source of coarse particles, and especially of the highly fluorescent fraction. Emission rates of FBAPs previously reported for lecture classes were well bounded by the experimental results obtained in this chamber study. In both settings, the size distribution of occupant FBAP emissions had a dominant mode in the 3-5 μm diameter range.

  15. 5 CFR 532.305 - Dominant industry.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Dominant industry. 532.305 Section 532... SYSTEMS Determining Rates for Principal Types of Positions § 532.305 Dominant industry. (a)(1) A specialized industry is a “dominant industry” if the number of wage employees in the wage area who are subject...

  16. Extracting entanglement from identical particles.

    Science.gov (United States)

    Killoran, N; Cramer, M; Plenio, M B

    2014-04-18

    Identical particles and entanglement are both fundamental components of quantum mechanics. However, when identical particles are condensed in a single spatial mode, the standard notions of entanglement, based on clearly identifiable subsystems, break down. This has led many to conclude that such systems have limited value for quantum information tasks, compared to distinguishable particle systems. To the contrary, we show that any entanglement formally appearing amongst the identical particles, including entanglement due purely to symmetrization, can be extracted into an entangled state of independent modes, which can then be applied to any task. In fact, the entanglement of the mode system is in one-to-one correspondence with the entanglement between the inaccessible identical particles. This settles the long-standing debate about the resource capabilities of such states, in particular spin-squeezed states of Bose-Einstein condensates, while also revealing a new perspective on how and when entanglement is generated in passive optical networks. Our results thus reveal new fundamental connections between entanglement, squeezing, and indistinguishability.

  17. Chemical characteristics and source of size-fractionated atmospheric particle in haze episode in Beijing

    Science.gov (United States)

    Tan, Jihua; Duan, Jingchun; Zhen, Naijia; He, Kebin; Hao, Jiming

    2016-01-01

    The abundance, behavior, and source of chemical species in size-fractionated atmospheric particle were studied with a 13-stage low pressure impactor (ELPI) during high polluted winter episode in Beijing. Thirty three elements (Al, Ca, Fe, K, Mg, Na, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, and Pb) and eight water soluble ions (Cl-, NO3-, SO42 -, NH4+, Na+, K+, Ca2 +, and Mg2 +) were determined by ICP/MS and IC, respectively. The size distribution of TC (OC + EC) was reconstructed. Averagely, 51.5 ± 5.3% and 74.1 ± 3.7% of the total aerosol mass was distributed in the sub-micron (PM1) and fine particle (PM2.5), respectively. A significant shift to larger fractions during heavy pollution episode was observed for aerosol mass, NH4+, SO42 -, NO3-, K, Fe, Cu, Zn, Cd, and Pb. The mass size distributions of NH4+, SO42 -, NO3-, and K were dominated by accumulation mode. Size distributions of elements were classified into four main types: (I) elements were enriched within the accumulation mode (water soluble ions. Dust, vehicle, aged coal combustion, and sea salt were identified, and the size resolved source apportionments were discussed. Aged coal combustion was the important source of fine particles and dust contributed most to coarse particle.

  18. On the Origin of Whistler Mode Radiation in the Plasmasphere

    Science.gov (United States)

    Green, James L.; Boardsen, Scott; Garcia, Leonard; Taylor, W. W. L.; Fung, Shing F.; Reinisch, B. W.

    2004-01-01

    The origin of whistler mode radiation in the plasmasphere is examined from three years of plasma wave observations from the Dynamics Explorer and three years from the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft. These data are used to construct plasma wave intensity maps of whistler mode radiation in the plasmasphere. The highest average intensities of the radiation in the wave maps show source locations and/or sites of wave amplification. Each type of emission is classified based on its magnetic latitude and longitude rather than any spectral feature. Equatorial electromagnetic (EM) emissions (approx. 30-330 Hz), plasmaspheric hiss (approx. 330 Hz - 3.3 kHz), chorus (approx. 2 kHz - 6 kHz), and VLF transmitters (approx. 10-50 kHz) are the main types of waves that are clearly delineated in the plasma wave maps. Observations of the equatorial EM emissions show that the most intense region is on or near the magnetic equator in the afternoon sector and that during times of negative B(sub z) (interplanetary magnetic field),the maximum intensity moves from L values of 3 to less than 2. These observations are consistent with the origin of this emission being particle-wave interactions in or near the magnetic equator. Plasmaspheric hiss shows high intensity at high latitudes and low altitudes (L shells from 2 to 4) and in the magnetic equator over L values from 2 to 3 in the early afternoon sector. The longitudinal distribution of the hiss intensity (excluding the enhancement at the equator) is similar to the distribution of lightning: stronger over continents than over the ocean, stronger in the summer than winter, and stronger on the dayside than nightside. These observations strongly support lightning as the dominant source for plasmaspheric hiss, which through particle-wave interactions, maintains the slot region in the radiation belts. The enhancement of hiss at the magnetic equator is consistent with particle-wave interactions. The chorus

  19. Epigenetic dominance of prion conformers.

    Directory of Open Access Journals (Sweden)

    Eri Saijo

    2013-10-01

    Full Text Available Although they share certain biological properties with nucleic acid based infectious agents, prions, the causative agents of invariably fatal, transmissible neurodegenerative disorders such as bovine spongiform encephalopathy, sheep scrapie, and human Creutzfeldt Jakob disease, propagate by conformational templating of host encoded proteins. Once thought to be unique to these diseases, this mechanism is now recognized as a ubiquitous means of information transfer in biological systems, including other protein misfolding disorders such as those causing Alzheimer's and Parkinson's diseases. To address the poorly understood mechanism by which host prion protein (PrP primary structures interact with distinct prion conformations to influence pathogenesis, we produced transgenic (Tg mice expressing different sheep scrapie susceptibility alleles, varying only at a single amino acid at PrP residue 136. Tg mice expressing ovine PrP with alanine (A at (OvPrP-A136 infected with SSBP/1 scrapie prions propagated a relatively stable (S prion conformation, which accumulated as punctate aggregates in the brain, and produced prolonged incubation times. In contrast, Tg mice expressing OvPrP with valine (V at 136 (OvPrP-V136 infected with the same prions developed disease rapidly, and the converted prion was comprised of an unstable (U, diffusely distributed conformer. Infected Tg mice co-expressing both alleles manifested properties consistent with the U conformer, suggesting a dominant effect resulting from exclusive conversion of OvPrP-V136 but not OvPrP-A136. Surprisingly, however, studies with monoclonal antibody (mAb PRC5, which discriminates OvPrP-A136 from OvPrP-V136, revealed substantial conversion of OvPrP-A136. Moreover, the resulting OvPrP-A136 prion acquired the characteristics of the U conformer. These results, substantiated by in vitro analyses, indicated that co-expression of OvPrP-V136 altered the conversion potential of OvPrP-A136 from the S to

  20. Corrugated waveguide mode purifier for TEM output in a dual-mode operation overmoded coaxial millimeter-wave generator

    Science.gov (United States)

    Bai, Zhen; Zhang, Jun; Zhong, Huihuang; Zhang, Dian

    2017-01-01

    A coaxial corrugated waveguide mode purifier is designed for a dual-mode operation overmoded coaxial millimeter-wave generator. With the purifier, the mixed TEM and TM01 modes output are purified into a pure TEM mode. Particle-in-cell (PIC) simulation shows that the purifier would not decrease the total output power of the generator, and plays an independent role to the upstream structure. Effects of mode composition ratio and phase difference on the purification ability of the purifier are also researched by both electromagnetism and PIC simulations, which show that the purifier has a certain tolerance for both the mode composition ratio and phase difference.

  1. Effect of biodiesel on the particle size distribution in the exhaust of common-rail diesel engine and the mechanism of nanoparticle formation

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Effect of biodiesel blends on the particle size distribution (PSD) of exhaust aerosol and the mechanism of nanoparticle formation were investigated with a modern common rail light-duty diesel engine. The results showed that PSD of diesel included two modes:nucleation mode (NM) and accumulation mode (CM). The criterion diameter of the two modes is 50 nm. Only CM was observed for all fuels under the condition of 50 N.m,2000 r/min. When the engine torque was higher than 150 N.m,log-modal PSD of diesel shifted to bimodal. At higher loads,if the biodiesel blend ratio was below 60%,the PSD of biodiesel blends still included the two modes. However,no NM particles were found for pure biodiesel. At lower loads,only CM was found in PSD of all fuels. Significant reduction of CM particles was found for biodiesel blends compared with diesel. Discussion on the mechanism of nanoparticle formation indicated that for the light-duty diesel engine with oxidation catalysts,fuel consumption and exhaust temperature increased with increasing the engine loads,and SO2 was converted to SO3 by catalyst which,in its hydrated form,could act as the precursor for biodiesel NM formation. Therefore,sulfur level of biodiesel blends dominates the nanoparticle formation in light-duty diesel engine with oxidation catalysts.

  2. Effect of biodiesel on the particle size distribution in the exhaust of common-rail diesel engine and the mechanism of nanoparticle formation

    Institute of Scientific and Technical Information of China (English)

    ZHANG XuSheng; ZHAO Hui; HU ZongJie; WU ZhiJun; LI LiGuang

    2009-01-01

    Effect of biodiesel blends on the particle size distribution (PSD) of exhaust aerosol and the mechanism of nanoparticle formation were investigated with a modern common rail light-duty diesel engine. The results showed that PSD of diesel included two modes: nucleation mode (NM) and accumulation mode (CM). The criterion diameter of the two modes is 50 rim. Only CM was observed for all fuels under the condition of 50 N. M, 2000 r/min. When the engine torque was higher than 150 N. M, log-modal PSD of diesel shifted to bimodal. At higher loads, if the biodiesel blend ratio was below 60%, the PSD of bio-diesel blends still included the two modes. However, no NM particles were found for pure biodiesel. At lower loads, only CM was found in PSD of all fuels. Significant reduction of CM particles was found for biodiesel blends compared with diesel. Discussion on the mechanism of nanoparUcle formation indi-cated that for the light-duty diesel engine with oxidation catalysts, fuel consumption and exhaust temperature increased with increasing the engine loads, and Sol was converted to SO3 by catalyst which, in its hydrated form, could act as the precursor for biodiesei NM formation. Therefore, sulfur level of biodiesel blends dominates the nanoparticle formation in light-duty diesel engine with oxidation catalysts.

  3. New longitudinal mode and compression of pair ions in plasma

    CERN Document Server

    Ehsan, Zahida; Shah, H A; Trines, R M G M

    2016-01-01

    Positive and negative ions forming so-called pair plasma differing in sign of their charge but asymmetric in mass and temperature support a new acoustic mode where damping of heavier ion dominates. The condition for the excitation of ion sound wave through electron beam induced Cherenkov instability is also investigated. This beam can generate a perturbation in the pair ion plasmas in the presence of electrons when there is number density, temperature and mass difference in the two species of ions. Basic emphasis is on the focusing of ion sound waves and we show how, in the area of localization of wave energy, the density of pair particles increases while electrons are pushed away from that region. Further, this localization of wave is dependent on the shape of the pulse. Considering the example of pancake and bullet shaped pulses, we find that only the former leads to compression of pair ions in the supersonic regime of the focusing region. Here possible existence of regions where pure pair particles can exi...

  4. Particle-In-Cell Simulation of RFQ in SSC - Linac

    CERN Document Server

    Chen, Xiao; You-Jin, Yuan; Yong, Liu; Jia-Wen, Xia; Yuan-Rong, Lu; Batygin, Yuri

    2010-01-01

    A 52MHz Radio Frequency Quadrupole (RFQ) linear accelerator (linac) is designed to serve as an initial structure for the SSC-linac system (injector into Separated Sector Cyclotron). The designed injection and output energy are 3.5 keV/u and 143 keV/u, respectively. Beam dynamics study in RFQ was done using 3-dimensional particle-in-cell code BEAMPATH [1]. Simulation results show that this RFQ structure is characterized by stable value of beam transmission efficiency (at least 95%) for both zero-current mode and for space charge dominated regime. The beam accelerated in RFQ has good quality in both transversal and longitudinal directions, and could be easily accepted by Drift Tube Linac (DTL). Effects of vane errors and of the space charge on beam parameters are studied as well to define the engineering tolerance for RFQ vane machining and alignment.

  5. Microtearing modes in tokamak discharges

    Energy Technology Data Exchange (ETDEWEB)

    Rafiq, T.; Kritz, A. H. [Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Weiland, J. [Department of Applied Physics, Chalmers University, S41296 Gothenburg (Sweden); Luo, L. [IBM Research, Oak Ridge, Tennessee 37831 (United States); Pankin, A. Y. [Tech-X Corporation, Boulder, Colorado 80308 (United States)

    2016-06-15

    Microtearing modes (MTMs) have been identified as a source of significant electron thermal transport in tokamak discharges. In order to describe the evolution of these discharges, it is necessary to improve the prediction of electron thermal transport. This can be accomplished by utilizing a model for transport driven by MTMs in whole device predictive modeling codes. The objective of this paper is to develop the dispersion relation that governs the MTM driven transport. A unified fluid/kinetic approach is used in the development of a nonlinear dispersion relation for MTMs. The derivation includes the effects of electrostatic and magnetic fluctuations, arbitrary electron-ion collisionality, electron temperature and density gradients, magnetic curvature, and the effects associated with the parallel propagation vector. An iterative nonlinear approach is used to calculate the distribution function employed in obtaining the nonlinear parallel current and the nonlinear dispersion relation. The third order nonlinear effects in magnetic fluctuations are included, and the influence of third order effects on a multi-wave system is considered. An envelope equation for the nonlinear microtearing modes in the collision dominant limit is introduced in order to obtain the saturation level. In the limit that the mode amplitude does not vary along the field line, slab geometry, and strong collisionality, the fluid dispersion relation for nonlinear microtearing modes is found to agree with the kinetic dispersion relation.

  6. Quasiadiabatic modes from viscous inhomogeneities

    Science.gov (United States)

    Giovannini, Massimo

    2016-04-01

    The viscous inhomogeneities of a relativistic plasma determine a further class of entropic modes whose amplitude must be sufficiently small since curvature perturbations are observed to be predominantly adiabatic and Gaussian over large scales. When the viscous coefficients only depend on the energy density of the fluid the corresponding curvature fluctuations are shown to be almost adiabatic. After addressing the problem in a gauge-invariant perturbative expansion, the same analysis is repeated at a nonperturbative level by investigating the nonlinear curvature inhomogeneities induced by the spatial variation of the viscous coefficients. It is demonstrated that the quasiadiabatic modes are suppressed in comparison with a bona fide adiabatic solution. Because of its anomalously large tensor to scalar ratio the quasiadiabatic mode cannot be a substitute for the conventional adiabatic paradigm so that, ultimately, the present findings seems to exclude the possibility of a successful accelerated dynamics solely based on relativistic viscous fluids. If the dominant adiabatic mode is not affected by the viscosity of the background a sufficiently small fraction of entropic fluctuations of viscous origin cannot be a priori ruled out.

  7. Microtearing modes in tokamak discharges

    Science.gov (United States)

    Rafiq, T.; Weiland, J.; Kritz, A. H.; Luo, L.; Pankin, A. Y.

    2016-06-01

    Microtearing modes (MTMs) have been identified as a source of significant electron thermal transport in tokamak discharges. In order to describe the evolution of these discharges, it is necessary to improve the prediction of electron thermal transport. This can be accomplished by utilizing a model for transport driven by MTMs in whole device predictive modeling codes. The objective of this paper is to develop the dispersion relation that governs the MTM driven transport. A unified fluid/kinetic approach is used in the development of a nonlinear dispersion relation for MTMs. The derivation includes the effects of electrostatic and magnetic fluctuations, arbitrary electron-ion collisionality, electron temperature and density gradients, magnetic curvature, and the effects associated with the parallel propagation vector. An iterative nonlinear approach is used to calculate the distribution function employed in obtaining the nonlinear parallel current and the nonlinear dispersion relation. The third order nonlinear effects in magnetic fluctuations are included, and the influence of third order effects on a multi-wave system is considered. An envelope equation for the nonlinear microtearing modes in the collision dominant limit is introduced in order to obtain the saturation level. In the limit that the mode amplitude does not vary along the field line, slab geometry, and strong collisionality, the fluid dispersion relation for nonlinear microtearing modes is found to agree with the kinetic dispersion relation.

  8. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Directory of Open Access Journals (Sweden)

    R. M. Healy

    2012-02-01

    mass was apportioned to fossil fuel and biomass burning respectively using the ATOFMS data compared with 85% and 15% respectively for BC estimated from the aethalometer model. On average, the mass size distribution for EC particles is bimodal; the smaller mode is attributed to locally emitted, mostly externally mixed EC particles, while the larger mode is dominated by aged, internally mixed ECOCNOx particles associated with continental transport events. Periods of continental influence were identified using the Lagrangian Particle Dispersion Model (LPDM "FLEXPART". A consistent minimum between the two EC mass size modes was observed at approximately 400 nm for the measurement period. EC particles below this size are attributed to local emissions using chemical mixing state information and contribute 79% of the scaled ATOFMS EC particle mass, while particles above this size are attributed to continental transport events and contribute 21% of the EC particle mass. These results clearly demonstrate the potential benefit of monitoring size-resolved mass concentrations for the separation of local and continental EC emissions. Knowledge of the relative input of these emissions is essential for assessing the effectiveness of local abatement strategies.

  9. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Science.gov (United States)

    Healy, R. M.; Sciare, J.; Poulain, L.; Kamili, K.; Merkel, M.; Müller, T.; Wiedensohler, A.; Eckhardt, S.; Stohl, A.; Sarda-Estève, R.; McGillicuddy, E.; O'Connor, I. P.; Sodeau, J. R.; Wenger, J. C.

    2012-02-01

    compared with 85% and 15% respectively for BC estimated from the aethalometer model. On average, the mass size distribution for EC particles is bimodal; the smaller mode is attributed to locally emitted, mostly externally mixed EC particles, while the larger mode is dominated by aged, internally mixed ECOCNOx particles associated with continental transport events. Periods of continental influence were identified using the Lagrangian Particle Dispersion Model (LPDM) "FLEXPART". A consistent minimum between the two EC mass size modes was observed at approximately 400 nm for the measurement period. EC particles below this size are attributed to local emissions using chemical mixing state information and contribute 79% of the scaled ATOFMS EC particle mass, while particles above this size are attributed to continental transport events and contribute 21% of the EC particle mass. These results clearly demonstrate the potential benefit of monitoring size-resolved mass concentrations for the separation of local and continental EC emissions. Knowledge of the relative input of these emissions is essential for assessing the effectiveness of local abatement strategies.

  10. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Directory of Open Access Journals (Sweden)

    R. M. Healy

    2011-11-01

    particle mass was apportioned to fossil fuel and biomass burning respectively using the ATOFMS data compared with 85 % and 15 % respectively for BC estimated from the aethalometer model. On average, the mass size distribution for EC particles is bimodal; the smaller mode is attributed to locally emitted, mostly externally mixed EC particles, while the larger mode is dominated by aged, internally mixed ECOCNOx particles associated with continental transport events. Periods of continental influence were identified using the Lagrangian Particle Dispersion Model (LPDM "FLEXPART". A consistent minimum between the two EC mass size modes was observed at approximately 400 nm for the measurement period. EC particles below this size are attributed to local emissions using chemical mixing state information and contribute 79 % of the scaled ATOFMS EC particle mass, while particles above this size are attributed to continental transport events and contribute 21 % of the EC particle mass. These results clearly demonstrate the potential benefit of monitoring size-resolved mass concentrations for the separation of local and continental EC emissions. Knowledge of the relative input of these emissions is essential for assessing the effectiveness of local abatement strategies.

  11. Effect of advanced and delayed rotation on the dominant flow pattern and its temporal evolution

    Science.gov (United States)

    Uksul, Esra; Krishna, Swathi; Mulleners, Karen

    2015-11-01

    During a flapping cycle of an insect, complex time dependent flows are produced as the wing reciprocates, producing a maximum lift at the stroke reversals. By flipping the wing rapidly at the end of each stroke, the insect modulates the flow around the wing and hence the aerodynamic forces necessary to hover. The duration and starting point of the flip play an important role in determining the amount of lift produced. To understand and tailor the effect of wing kinematics on the aerodynamic performance we focussed on the vortex dynamics of the flow field. Phase-averaged data from particle image velocimetry was used to evaluate the flow features inherent to changes in rotation during a stroke of a flat plate, which is modelled based on hoverfly characteristics. The period of rotation is one-third of the total time period. A +10% phase shift is used for delayed rotation, a -10% phase shift for advanced rotation. Vortex detection methods like the λ2 and Γ2 criteria are used to determine the effect of a delay or early rotation on the trajectories, size, shape and location of the prominent vortical structures. Proper orthogonal decomposition is used to study the influence of the phase-shifts on the dominant mode structure and the related time-scales.

  12. Search for charmed particles

    Energy Technology Data Exchange (ETDEWEB)

    Ascoli, G.; Cooper, J.; Francis, W.; Holloway, L.; Kirk, T.; Koester, L.; Kruse, U.; Sard, R.; /Illinois U., Urbana; Loomis, A.; Sessoms, A.; Wilson, R.; /Harvard U.

    1975-10-01

    We propose to use the CCM spectrometer to carry out a sensitive search for charmed particles produced in strong interactions at a nominal beam energy of 150 GeV/c. We limit ourselves to production in the beam diffraction region for reasons of acceptance and reconstruction. We present results of a test run undertaken in April 1975 to demonstrate the feasibility of K{sub S}{sup 0} trigger, which we incorporate in the present proposal. Results of the test are combined with new insights which increase our sensitivity to charmed particle production by a large factor. We request a total of 2 x 10{sup 11} negative pions at a rate of 10{sup 6} per pulse. With this illumination we estimate that we can measure a large number of hadronic decay modes. We make estimates of enhancements in mass spectra from charmed particle production and decay and calculate expected backgrounds using data from existing experiments. With conservative assumptions about the charmed particle model, we calculate effects corresponding to ten or more standard deviations in our most favorable channels.

  13. On Minus Paired-Domination in Graphs

    Institute of Scientific and Technical Information of China (English)

    邢化明; 孙良

    2003-01-01

    The study of minus paired-domination of a graph G=(V,E) is initiated. Let SV be any paired-dominating set of G, a minus paired-dominating function is a function of the form f∶V→{-1,0,1} such that f(v)=1 for v∈S, f(v)≤0 for v∈V-S, and f(N[v])≥1 for all v∈V. The weight of a minus paired-dominating function f is w(f)=∑f(v), over all vertices v∈V. The minus paired-domination number of a graph G is γ-p(G)=min{w(f)|f is a minus paired-dominating function of G}. On the basis of the minus paired-domination number of a graph G defined, some of its properties are discussed.

  14. Influences of hot-isostatic-pressing temperature on microstructure, tensile properties and tensile fracture mode of Inconel 718 powder compact

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Litao [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China); University of Chinese Academy of Sciences, Beijing (China); Sun, Wenru; Cui, Yuyou [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China); Yang, Rui, E-mail: ryang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China)

    2014-04-01

    Inconel 718 powders have been hot-isostatic-pressed (HIPed) at representative temperatures to investigate the variations in microstructure, tensile properties and tensile fracture mode of the powder compact. Microstructure of the powder compacts were characterized by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and so on. The results showed that the interdendritic precipitates inherited from the powders were partially retained in the powder compacts when the powders were HIPed at or below 1210 °C but were eliminated when HIPed at and above 1260 °C. The grain size uniformity of the powder compacts first increases and then decreases with increasing HIPing temperature. Prior particle boundaries (PPBs) were observed in the powder compacts HIPed at and below 1260 °C but was eliminated when HIPed at 1275 °C. The PPBs were decorated with carbide particles, the amount of the carbide particles at the PPBs decreases with increasing HIPing temperature. Most of the PPBs were pinned by the carbide particles in the compacts HIPed at 1140 °C. When the HIPing temperature was increased to 1210 °C and 1260 °C, a large number of PPBs de-pinned and moved beyond the pinning carbide particles, leading to grain growth and leaving carbide particles at the site of the original PPBs within the new grains. With increasing HIPing temperature, the 0.2% yield strength of the powder compacts at 650 °C decreases, the tensile elongation increases, and the tensile fracture mode changed from inter-particle dominant fracture to fully dimple ductile fracture.

  15. Mode couplings and resonance instabilities in dust clusters.

    Science.gov (United States)

    Qiao, Ke; Kong, Jie; Oeveren, Eric Van; Matthews, Lorin S; Hyde, Truell W

    2013-10-01

    The normal modes for three to seven particle two-dimensional (2D) dust clusters in a complex plasma are investigated using an N-body simulation. The ion wakefield downstream of each particle is shown to induce coupling between horizontal and vertical modes. The rules of mode coupling are investigated by classifying the mode eigenvectors employing the Bessel and trigonometric functions indexed by order integers (m, n). It is shown that coupling only occurs between two modes with the same m and that horizontal modes having a higher shear contribution exhibit weaker coupling. Three types of resonances are shown to occur when two coupled modes have the same frequency. Discrete instabilities caused by both the first and third type of resonances are verified and instabilities caused by the third type of resonance are found to induce melting. The melting procedure is observed to go through a two-step process with the solid-liquid transition closely obeying the Lindemann criterion.

  16. Ocular Dominance and Handedness in Golf Putting.

    Science.gov (United States)

    Dalton, Kristine; Guillon, Michel; Naroo, Shehzad A

    2015-10-01

    In golf, the impact of eye-hand dominance on putting performance has long been debated. Eye-hand dominance is thought to impact how golfers judge the alignment of the ball with the target and the club with the ball, as well as how golfers visualize the line of the putt when making decisions about the force needed to hit the ball. Previous studies have all measured ocular dominance in primary gaze only, despite golfers spending a significant amount of their time in a putting stance (bent at the hips, head tilted down). Thus, the purpose of this study was to assess ocular dominance in both primary gaze (aligning the ball with the target) and putting gaze (addressing the ball and aligning the club). This study investigated measuring pointing ocular dominance in both primary and putting gaze positions on 31 golfers (14 amateur, 7 club professionals, and 10 top professionals). All players were right-handed golfers, although one reported having no hand dominance and one reported being strongly left hand dominant. The results showed that (1) primary and putting gaze ocular dominances are not equal, nor are they predictive of each other; (2) the magnitude of putting ocular dominance is significantly less than the magnitude of primary gaze ocular dominance; (3) ocular dominance is not correlated with handedness in either primary or putting gaze; and (4) eye-hand dominance is not associated with increased putting skill, although ocular dominance may be associated with increased putting success. It is important that coaches assess golfers' ocular dominance in both primary and putting gaze positions to ensure they have the most accurate information upon which to base their vision strategy decisions.

  17. Preparation of topological modes by Lyapunov control.

    Science.gov (United States)

    Shi, Z C; Zhao, X L; Yi, X X

    2015-09-08

    By Lyapunov control, we present a proposal to drive quasi-particles into a topological mode in quantum systems described by a quadratic Hamiltonian. The merit of this control is the individual manipulations on the boundary sites. We take the Kitaev's chain as an illustration for Fermi systems and show that an arbitrary excitation mode can be steered into the Majorana zero mode by manipulating the chemical potential of the boundary sites. For Bose systems, taking the noninteracting Su-Schrieffer-Heeger (SSH) model as an example, we illustrate how to drive the system into the edge mode. The sensitivity of the fidelity to perturbations and uncertainties in the control fields and initial modes is also examined. The experimental feasibility of the proposal and the possibility to replace the continuous control field with square wave pulses is finally discussed.

  18. Interferometric detection of mode splitting for whispering gallery mode biosensors

    CERN Document Server

    Knittel, Joachim; Lee, Kwan H; Bowen, Warwick P

    2010-01-01

    Sensors based on whispering gallery mode resonators can detect single nanoparticles and even single molecules. Particles attaching to the resonator induce a doublet in the transmission spectrum which provides a self-referenced detection signal. However, in practice this spectral feature is often obscured by the width of the resonance line which hides the doublet structure. This happens particularly in liquid environments that reduce the effective Q factor of the resonator. In this paper we demonstrate an interferometric set-up that allows the direct detection of the hidden doublet and thus provides a pathway for developing practical sensor applications.

  19. Intervention reducing particle exposure in Homes of 50+ year olds

    DEFF Research Database (Denmark)

    Gunnarsen, Lars Bo; Spilak, Michal; Frederiksen, Marie

    2016-01-01

    An intervention reducing particle exposure was conducted in 27 apartments of 50+ year olds in Denmark. Two recirculating particle filtration units were installed in each apartment. They operated for two weeks in active filtration mode and for two weeks in sham mode in a randomized cross-over desi...

  20. The drop in the cosmic star formation rate below redshift 2 is caused by a change in the mode of gas accretion and by AGN feedback

    CERN Document Server

    van de Voort, Freeke; Booth, C M; Vecchia, Claudio Dalla

    2011-01-01

    The cosmic star formation rate is observed to drop sharply after redshift z=2. We use a large, cosmological, smoothed particle hydrodynamics simulation to investigate how this decline is related to the evolution of gas accretion and to outflows driven by active galactic nuclei (AGN). We find that the drop in the star formation rate follows a corresponding decline in the global cold-mode accretion rate density onto haloes, but with a delay of order the gas consumption time scale in the interstellar medium. Here we define cold-mode (hot-mode) accretion as gas that is accreted and whose temperature has never exceeded (did exceed) 10^5.5 K. In contrast to cold-mode accretion, which peaks at z~3, the hot mode continues to increase to z~1 and remains roughly constant thereafter. By the present time, the hot mode strongly dominates the global accretion rate onto haloes. Star formation does not track hot-mode halo accretion because most of the hot halo gas never accretes onto galaxies. AGN feedback plays a crucial ro...

  1. Modelling Transportation of Efavirenz: Inference on possibility of mixed modes of transportation and kinetic solubility

    Directory of Open Access Journals (Sweden)

    Tafireyi eNemaura

    2015-06-01

    Full Text Available Understanding drug transportation mechanisms in the human body is of paramount importance in modelling Pharmacokinetic-Pharmacodynamic relationships. This work gives a novel general model of efavirenz transportation projections based on concentrations simulated from patients on a dose of 600mg. The work puts forward a proposition that transportation can wholly be modeled by concentration and time in a uniform volumetric space. Furthermore, movement entities are used to inform the state of kinetic solubility of a solution. There is use of Ricker’s model, and forms of the Hill’s equation in modelling transportation. Characterization on the movement rates of solution particle are suggested in relation to advection rate of solution particle. At turning points on the transportation rate of solution particle vs concentration curve, a suggestion of possibly change of dominance in the mode of transportation and saturation is made. There are four movement rates postulated at primary micro-level transportation, that are attributed to convection, diffusion (passive transportation ( EI and energy dependent system transportation ( ED in relation to advection. Furthermore, a new parameter is introduced which is defined as an advection rate constant of solution particle. It is postulated to be dependent on two rate constants of solution particle, that is a convection rate constant of solution particle and a saturable transportation rate constant of solution particle. At secondary micro-level transportation, the results show convection as sum of advection and saturable transportation. The kinetics of dissolution of efavirenz in the solution space is postulated. Relatively, a good level of kinetics of dissolution is projected in the concentration region 0−32.82μg/ml.

  2. Hand Dominance and Common Hand Conditions.

    Science.gov (United States)

    Lutsky, Kevin; Kim, Nayoung; Medina, Juana; Maltenfort, Mitchell; Beredjiklian, Pedro K

    2016-05-01

    The goals of this study were to (1) assess how frequently patients present for evaluation of common hand disorders in relation to hand dominance and (2) evaluate the effect of hand dominance on function in patients with these conditions. The authors hypothesized that (1) the majority of patients who seek evaluation would have a condition that affects the dominant hand, and (2) disability scores would be worse if the dominant hand is involved. They retrospectively reviewed the records of consecutive patients who presented for treatment to their institution with unilateral symptoms of 5 common disorders of the hand: carpal tunnel syndrome (CTS), de Quervain's tenosynovitis (DEQ), lateral epicondylitis (LE), hand osteoarthritis (OA), and trigger finger (TF). The authors assessed the effect of diagnosis and hand dominance on Disabilities of the Arm, Shoulder and Hand (DASH) scores. The study group comprised 1029 patients (379 men and 650 women) with a mean age of 59.5 years. Ninety percent were right-hand dominant. The dominant and nondominant hands were affected with relatively equal frequency for CTS, DEQ, OA, and TF (range, 45%-53%). Patients with LE had a significantly higher incidence of dominant hand involvement. Men had lower DASH scores than women by an average of 7.9 points, and DASH scores were significantly but slightly higher for the overall group (3.2 points) when the dominant side was affected. Men with LE and women with TF and OA had significantly higher DASH scores when their dominant extremity was affected. Common hand disorders such as CTS, DEQ, OA, and TF affect the dominant and nondominant hands in roughly equivalent proportions, whereas LE is more common on the dominant side. Dominant hand involvement results in significantly worse DASH scores, although the magnitude of this is relatively small. Women have significantly higher DASH scores than men for the conditions evaluated. [Orthopedics. 2016; 39(3):e444-e448.].

  3. Study of multiparticle production by gluon dominance model (Part II)

    CERN Document Server

    Ermolov, P F; Kuraev, E A; Kutov, A V; Nikitin, V A; Pankov, A A; Roufanov, I A; Zhidkov, N K

    2005-01-01

    The gluon dominance model presents a description of multiparticle production in proton-proton collisions and proton-antiproton annihilation. The collective behavior of secondary particles in $pp$-interactions at 70 GeV/c and higher is studied in the project {\\bf "Thermalization"}. The obtained neutral and charged multiplicity distribution parameters explain some RHIC-data. The gluon dominance model is modified by the inclusion of intermediate quark topology for the multiplicity distribution description in the pure $p\\bar p$-annihilation at few tens GeV/c and explains behavior of the second correlative moment. This article proposes a mechanism of the soft photon production as a sign of hadronization. Excess of soft photons allows one to estimate the emission region size.

  4. ELECTROSTATIC MODE ASSOCIATED WITH PINCH VELOCITY IN RFPS

    Energy Technology Data Exchange (ETDEWEB)

    DELZANNO, GIAN LUCA [Los Alamos National Laboratory; FINN, JOHN M. [Los Alamos National Laboratory; CHACON, LUIS [Los Alamos National Laboratory

    2007-02-08

    The existence of a new electrostatic instability is shown for RFP (reversed field pinch) equilibria. This mode arises due to the non-zero equilibrium radial flow (pinch flow). In RFP simulations with no-stress boundary conditions on the tangential velocity at the radial wall, this electrostatic mode is unstable and dominates the nonlinear dynamics, even in the presence of the MHD modes typically responsible for the reversal of the axial magnetic field at edge. Nonlinearly, this mode leads to two beams moving azimuthally towards each other, which eventually collide. The electrostatic mode can be controlled by using Dirichlet (no-slip) boundary conditions on the azimuthal velocity at the radial wall.

  5. Visualizing a Dusty Plasma Shock Wave via Interacting Multiple-Model Mode Probabilities

    OpenAIRE

    Oxtoby, Neil P.; Ralph, Jason F.; Durniak, Céline; Samsonov, Dmitry

    2011-01-01

    Particles in a dusty plasma crystal disturbed by a shock wave are tracked using a three-mode interacting multiple model approach. Color-coded mode probabilities are used to visualize the shock wave propagation through the crystal.

  6. Carbon particles

    Science.gov (United States)

    Hunt, Arlon J.

    1984-01-01

    A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

  7. Plate-mode waves in phononic crystal thin slabs: mode conversion.

    Science.gov (United States)

    Chen, Jiu-Jiu; Bonello, Bernard; Hou, Zhi-Lin

    2008-09-01

    We have computed the dispersion curves of plate-mode waves propagating in periodic composite structures composed of isotropic aluminum cylinders embedded in an isotropic nickel background. The phononic crystal has a square symmetry and the calculation is based on the plane-wave expansion method. Along GammaX or GammaM directions, shear-horizontal modes do not couple to the Lamb wave modes which are polarized in the sagittal plane. Whatever the direction of propagation in between GammaX and GammaM, shear-horizontal modes convert to Lamb waves and couple with the flexural and dilatational modes. This phenomenon is demonstrated both through the mode splitting in the lower-order symmetric band structure and through the calculation of all three components of the particle displacements. The phononic case is different from the pure isotropic plate case where shear-horizontal waves decouple from Lamb waves whatever the direction of propagation.

  8. Particle Formation in Moving Grate Boilers Fired with Wood Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Bioenergy Technology; Pagels, Joalum; Szpila, Aneta; Bohgard, Mats [Lund Univ. (Sweden). Div. of Ergonomics and Aerosol Technology; Swietlicki, Erik [Lund Univ. (Sweden). Div. of Nuclear Physics

    2005-07-01

    In this work the size resolved elemental particle concentration from five district heating moving grate boilers operating on different woody biofuels have been analysed in order to investigate the general formation mechanism in this kind of boiler. Aerosol particles were characterised in the five boilers operating on forest residues, pellets, or saw dust. The aerosol particles were sampled downstream of the multicyclone using a dilution system in order to decrease temperature and humidity. The proposed mechanism for formation of the fine mode is homogenous chemical reactions to form potassium sulphate, which nucleates to form the fine particle mode at high temperatures. The concentration profile of zinc indicates that zinc-containing species in some cases may form particles by gas-to particle conversion prior to the nucleation of potassium sulphate. As the flue gas temperature decrease below 650 C potassium chloride will condense on the surfaces of the previously formed particles. The proposed mechanism for inception of the coarse particle mode was fragmentation/dispersion of refractory material from the burning char or from the residual ash in the bed. The ratios of the potentially volatile elements potassium, sulphur and chlorine, were similar in the fine and the coarse mode, indicating the material had the same origin in both modes. The presence of the volatile components may be explained by non-complete vaporisation, chemical surface reactions, re-entrainment of deposited particles, and coagulation with the fine particle mode.

  9. Chemical mass balance of refractory particles (T=300 °C at the tropospheric research site Melpitz, Germany

    Directory of Open Access Journals (Sweden)

    L. Poulain

    2013-10-01

    Full Text Available In the fine particle mode (aerodynamic diameter <1 μm refractory material has been associated with black carbon (BC and low-volatile organics and, to a lesser extent, with sea salt and mineral dust. This work analyses refractory particles at the tropospheric research station Melpitz (Germany, combining experimental methods such as a mobility particle size spectrometer (3–800 nm, a thermodenuder operating at 300 °C, a multi-angle absorption photometer (MAAP, and an aerosol mass spectrometer (AMS. The data were collected during two atmospheric field experiments in May/June 2008 as well as February/March 2009. As a basic result, we detected average refractory particle volume fractions of 11±3% (2008 and 17±8% (2009. In both periods, BC was in close linear correlation with the refractory fraction, but not sufficient to quantitatively explain the refractory particle mass concentration. Based on the assumption that BC is not altered by the heating process, the refractory particle mass fraction could be explained by the sum of black carbon BC (47% in summer, 59% in winter and a refractory organic contribution estimated as part of the Low-Volatility Oxygenated Organic Aerosol (LV-OOA (53% in summer, 41% in winter; the latter was identified from AMS data by factor analysis. Our results suggest that organics were more volatile in summer (May–June 2008 than in winter (February/March 2009. Although carbonaceous compounds dominated the sub-μm refractory particle mass fraction most of the time, a cross-sensitivity to partially volatile aerosol particles of maritime origin could be seen. These marine particles could be distinguished, however, from the carbonaceous particles by a characteristic particle volume size distribution. The paper discusses the uncertainty of the volatility measurements and outlines the possible merits of volatility analysis as part of continuous atmospheric aerosol measurements.

  10. Particle physics

    CERN Document Server

    Martin, Brian R

    2017-01-01

    An accessible and carefully structured introduction to Particle Physics, including important coverage of the Higgs Boson and recent progress in neutrino physics. Fourth edition of this successful title in the Manchester Physics series. Includes information on recent key discoveries including : An account of the discovery of exotic hadrons, beyond the simple quark model; Expanded treatments of neutrino physics and CP violation in B-decays; An updated account of ‘physics beyond the standard model’, including the interaction of particle physics with cosmology; Additional problems in all chapters, with solutions to selected problems available on the book’s website; Advanced material appears in optional starred sections.

  11. Variable geometry two mode levitation trap

    Science.gov (United States)

    Babič, D.; Čadež, A.

    1999-11-01

    Construction and operation of the electrodynamic levitation trap which can be operated in a passive and an active mode is described. This combination together with variable electrode geometry simplifies the trap's design and simultaneously gives more flexibility with respect to different kinds of measurements. Sample measurements of mechanocaloric effect caused by nonuniform heating of a single levitated particle are presented and discussed.

  12. Developing parameters for multi-mode ambient air models including the nanometer mode

    Science.gov (United States)

    Tronville, Paolo; Rivers, Richard

    2017-06-01

    The particle count, surface and mass in an occupied space can be modeled when the HVAC system airflows are known, along with the particle-size distribution for outdoor air, internal generation rates as a function of particle size, and the efficiency as a function of particle size for filters present. Outdoor air particle-size distribution is rarely available, but measures of particle mass concentration, PM2.5 and PM10, are often available for building locations. Outdoor air aerosol size distributions are well modeled by sums of two or three log-normal distributions, with essentially all mass in two larger modes. Studies have also shown that some mode parameters are, in general, related by simple functions. This paper shows how these relationships can be combined with known characteristics of PM2.5 and PM10 samplers to create reasonable inclusive models of outdoor air aerosol-size distributions. This information plus knowledge of indoor particle generation allows calculation of aerosol mass in occupied spaces. Estimation of parameters of aerosol modes with sizes below100 nm and measurement of filter efficiencies in that range are described.

  13. Electron-Dominated Spontaneous Bifurcation of Harris Equilibrium

    CERN Document Server

    Lee, Kuang-Wu

    2012-01-01

    In this letter the spontaneous bifurcation of Harris equilibrium current sheet is reported. The collisionless current bifurcation is simulated by a 2D particle-in-cell approach. Explicit particle advancing method is used to resolve the transient electron dynamics. Unlike previous implicit investigations no initial perturbations is applied to trigger current bifurcation. Instead, an electron-dominated spontaneously bifurcation is observed. Electromagnetic fluctuations grow from thermal noise initially. Soon the noise triggers the eigenmodes and eventually causes current sheet bifurcation. The relative entropy of the bifurcated state exceeds the value of initial Harris equilibrium. It is also found that the Helmholtz free energy decreases in the bifurcation process. Hence it is concluded that Harris equilibrium evolves toward a more stable (smaller free energy) bifurcated state.

  14. On trees with total domination number equal to edge-vertex domination number plus one

    Indian Academy of Sciences (India)

    B Krishnakumari; Y B Venkatakrishnan; Marcin Krzywkowski

    2016-05-01

    An edge $e \\in E(G)$ dominates a vertex $v \\in V(G)$ if $e$ is incident with $v$ or $e$ is incident with a vertex adjacent to $v$. An edge-vertex dominating set of a graph $G$ is a set $D$ of edges of $G$ such that every vertex of $G$ is edge-vertex dominated by an edge of $D$. The edge-vertex domination number of a graph $G$ is the minimum cardinality of an edge-vertex dominating set of $G$. A subset $D \\subseteq V(G)$ is a total dominating set of $G$ if every vertex of $G$ has a neighbor in $D$. The total domination number of $G$ is the minimum cardinality of a total dominating set of $G$. We characterize all trees with total domination number equal to edge-vertex domination number plus one.

  15. Electroconvulsive therapy and determination of cerebral dominance

    OpenAIRE

    Dragovic, Milan; Allet, Lindsay; Janca, Aleksandar

    2004-01-01

    Electroconvulsive therapy (ECT) often results in a number of short- and long-time side effects including memory impairment for past and current events, which can last for several months after ECT treatment. It has been suggested that unilateral ECT (uECT) with electrodes placed over the non-dominant (typically right) hemisphere significantly reduces side effects, especially memory disturbances. It is important to note that cerebral dominance equates to speech dominance and avoiding this area ...

  16. Minimum Dominating Tree Problem for Graphs

    Institute of Scientific and Technical Information of China (English)

    LIN Hao; LIN Lan

    2014-01-01

    A dominating tree T of a graph G is a subtree of G which contains at least one neighbor of each vertex of G. The minimum dominating tree problem is to find a dominating tree of G with minimum number of vertices, which is an NP-hard problem. This paper studies some polynomially solvable cases, including interval graphs, Halin graphs, special outer-planar graphs and others.

  17. Harmonic Oscillators and Elementary Particles

    CERN Document Server

    Sobouti, Y

    2016-01-01

    Two dynamical systems with same symmetry should have features in common, and as far as their shared symmetry is concerned, one may represent the other. The three light quark constituents of the hadrons, a) have an approximate flavor SU(3) symmetry, b) have an exact color SU(3) symmetry, and c) as spin 1/2 particles, have a Lorentz SO(3,1) symmetry. So does a 3D harmonic oscillator. a) Its Hamiltonian has the SU(3) symmetry, breakable if the 3 fundamental modes of oscillation are not identical. b) The 3 directions of oscillation have the permutation symmetry. This enables one to create three copies of unbreakable SU(3) symmetry for each mode of the oscillation, and mimic the color of the elementary particles. And c) The Lagrangian of the 3D oscillator has the SO(3,1) symmetry. This can be employed to accommodate the spin of the particles. In this paper we draw up a one-to-one correspondence between the eigen modes of the Poisson bracket operator of the 3D oscillator and the flavor multiplets of the particles, ...

  18. Semi-strong split domination in graphs

    Directory of Open Access Journals (Sweden)

    Anwar Alwardi

    2014-06-01

    Full Text Available Given a graph $G = (V,E$, a dominating set $D subseteq V$ is called a semi-strong split dominating set of $G$ if $|V setminus D| geq 1$ and the maximum degree of the subgraph induced by $V setminus D$ is 1. The minimum cardinality of a semi-strong split dominating set (SSSDS of G is the semi-strong split domination number of G, denoted $gamma_{sss}(G$. In this work, we introduce the concept and prove several results regarding it.

  19. Neighborhood connected perfect domination in graphs

    Directory of Open Access Journals (Sweden)

    Kulandai Vel M.P.

    2012-12-01

    Full Text Available Let $G = (V, E$ be a connected graph. A set $S$ of vertices in $G$ is a perfect dominating set if every vertex $v$ in $V-S$ is adjacent to exactly one vertex in $S$. A perfect dominating set $S$ is said to be a neighborhood connected perfect dominating set (ncpd-set if the induced subgraph $$ is connected. The minimum cardinality of a ncpd-set of $G$ is called the neighborhood connected perfect domination number of $G$ and is denoted by $\\gamma_{ncp}(G$. In this paper we initiate a study of this parameter.

  20. Autosomal dominant adult neuronal ceroid lipofuscinosis

    NARCIS (Netherlands)

    Nijssen, Peter C.G.

    2011-01-01

    this thesis investigates a family with autosomal dominant neuronal ceroid lipofuscinosis, with chapters on clinical neurology, neuropathology, neurogenetics, neurophysiology, auditory and visual aspects.

  1. Cycles are determined by their domination polynomials

    CERN Document Server

    Akbari, Saieed

    2009-01-01

    Let $G$ be a simple graph of order $n$. A dominating set of $G$ is a set $S$ of vertices of $G$ so that every vertex of $G$ is either in $S$ or adjacent to a vertex in $S$. The domination polynomial of $G$ is the polynomial $D(G,x)=\\sum_{i=1}^{n} d(G,i) x^{i}$, where $d(G,i)$ is the number of dominating sets of $G$ of size $i$. In this paper we show that cycles are determined by their domination polynomials.

  2. Consumers, health insurance and dominated choices.

    Science.gov (United States)

    Sinaiko, Anna D; Hirth, Richard A

    2011-03-01

    We analyze employee health plan choices when the choice set offered by their employer includes a dominated plan. During our study period, one-third of workers were enrolled in the dominated plan. Some may have selected the plan before it was dominated and then failed to switch out of it. However, a substantial number actively chose the dominated plan when they had an unambiguously better choice. These results suggest limitations in the ability of health reform based solely on consumer choice to achieve efficient outcomes and that implementation of health reform should anticipate, monitor and account for this consumer behavior.

  3. Mode spectrum and temporal soliton formation in optical microresonators

    CERN Document Server

    Herr, T; Jost, J D; Mirgorodskiy, I; Lihachev, G; Gorodetsky, M L; Kippenberg, T J

    2013-01-01

    The formation of temporal dissipative solitons in optical microresonators enables compact, high repetition rate sources of ultra-short pulses as well as low noise, broadband optical frequency combs with smooth spectral envelopes. Here we study the influence of the resonator mode spectrum on temporal soliton formation. Using frequency comb assisted diode laser spectroscopy, the measured mode structure of crystalline MgF2 resonators are correlated with temporal soliton formation. While an overal general anomalous dispersion is required, it is found that higher order dispersion can be tolerated as long as it does not dominate the resonator's mode structure. Mode coupling induced avoided crossings in the resonator mode spectrum are found to prevent soliton formation, when affecting resonator modes close to the pump laser. The experimental observations are in excellent agreement with numerical simulations based on the nonlinear coupled mode equations, which reveal the rich interplay of mode crossings and soliton f...

  4. Contrasting organic aerosol particles from boreal and tropical forests during HUMPPA-COPEC-2010 and AMAZE-08 using coherent vibrational spectroscopy

    Directory of Open Access Journals (Sweden)

    C. J. Ebben

    2011-10-01

    Full Text Available We present the vibrational sum frequency generation spectra of organic particles collected in a boreal forest in Finland and a tropical forest in Brazil. These spectra are compared to those of secondary organic material produced in the Harvard Environmental Chamber. By comparing coherent vibrational spectra of a variety of terpene and olefin reference compounds, along with the secondary organic material synthesized in the environmental chamber, we show that submicron aerosol particles sampled in Southern Finland during HUMPPA-COPEC-2010 are composed to a large degree of material similar in chemical composition to synthetic α-pinene-derived material. For material collected in Brazil as part of AMAZE-08, the organic component is found to be chemically complex in the coarse mode but highly uniform in the fine mode. When combined with histogram analyses of the isoprene and monoterpene abundance recorded during the HUMPPA-COPEC-2010 and AMAZE-08 campaigns, the findings presented here indicate that if air is rich in monoterpenes, submicron-sized secondary aerosol particles that form under normal OH and O3 concentration levels can be described in terms of their hydrocarbon content as being similar to α-pinene-derived model secondary organic aerosol particles. If the isoprene concentration dominates the chemical composition of organic compounds in forest air, then the hydrocarbon component of secondary organic material in the submicron size range is not simply well-represented by that of isoprene-derived model secondary organic aerosol particles but is more complex. Throughout the climate-relevant size range of the fine mode, however, we find that the chemical composition of the secondary organic particle material from such air is invariant with size, suggesting that the particle growth does not change the chemical composition of the hydrocarbon component of the particles in a significant way.

  5. Contrasting organic aerosol particles from boreal and tropical forests during HUMPPA-COPEC-2010 and AMAZE-08 using coherent vibrational spectroscopy

    Directory of Open Access Journals (Sweden)

    C. J. Ebben

    2011-06-01

    Full Text Available We present the vibrational sum frequency generation spectra of organic particles collected in a boreal forest in Finland and a tropical forest in Brazil. These spectra are compared to those of secondary organic material produced in the Harvard Environmental Chamber. By comparing coherent vibrational spectra of a variety of terpene and olefin reference compounds, along with the secondary organic material synthesized in the environmental chamber, we show that submicron aerosol particles sampled in Southern Finland during HUMPPA-COPEC-2010 are composed to a large degree of material similar in chemical composition to synthetic α-pinene-derived material. For material collected in Brazil as part of AMAZE-08, the organic component is found to be chemically complex in the coarse mode but highly uniform in the fine mode. When combined with histogram analyses of the isoprene and monoterpene abundance recorded during the HUMPPA-COPEC-2010 and AMAZE-08 campaigns, the findings presented here indicate that if air is rich in monoterpenes, submicron-sized secondary aerosol particles that form under normal OH and O3 concentration levels can be described in terms of their hydrocarbon content as being similar to α-pinene-derived model secondary organic aerosol particles. If the isoprene concentration dominates the chemical composition of organic compounds in forest air, then the hydrocarbon component of secondary organic material in the submicron size range is not simply well-represented by that of isoprene-derived model secondary organic aerosol particles but is more complex. Throughout the climate-relevant size range of the fine mode, however, we find that the chemical composition of the secondary organic particle material from such air is invariant with size, suggesting that the particle growth does not change the chemical composition of the hydrocarbon component of the particles in a significant way.

  6. Light Absorption of Biogenic Aerosol Particles in Amazonia

    Science.gov (United States)

    Holanda, B. A.; Artaxo, P.; Ferreira De Brito, J.; Barbosa, H. M.; Andreae, M. O.; Saturno, J.; Pöhlker, C.; Holben, B. N.; Schafer, J.

    2014-12-01

    Aerosol absorption is a key issue in proper calculation of aerosol radiative forcing. Especially in the tropics with the dominance of natural biogenic aerosol and brown carbon, the so called anomalous absorption is of particular interest. A special experiment was designed to study the wavelength dependence of aerosol absorption for PM2.5 as well as for PM10 particles in the wet season in Central Amazonia. Aerosol analysis occurred from May to August 2014, in the ZF2 ecological reservation, situated at about 55 km North of Manaus in very pristine conditions Two 7 wavelengths AE33 Aethalometers were deployed measuring in parallel, but with a PM2.5 and PM10 inlets. Two MAAP (Multiangle Aerosol Absorption Photometer) were operated in parallel with the AE33 exactly at the same PM2.5 and PM10 inlets. Organic and elemental carbon was analyzed using collection with quartz filters and analysis using a Sunset OC/EC analyzer. Aerosol light scattering for 3 wavelengths was measured using Air Photon and TSI Nephelometers. Aerosol size distribution was measured with one TSI SMPS and a GRIMM OPC to have the size range from 10 nm to 10 micrometers. Particles were measured under dry conditions using diffusion dryers. Aerosol optical depth and absorption was also measured with an AERONET sunphotometer operated close to the site. As the experiment was run in the wet season, very low equivalent black carbon (EBC) were measured, with average concentrations around 50 ng/m³ during May, increasing to 130 ng/m³ in June and July. The measurements adjusted for similar wavelengths shows excellent agreement between the MAAP and AE33 for both inlets (PM2.5 and PM10). It was not possible statistically infer absorption from the coarse mode biogenic particles, since the absorption was completely dominated by fine mode particles. AERONET measurements shows very low values of AOD, at 0.17 at 500 nm and 0.13 at 870 nm, with very low absorption AOD values at 0.00086 at 676 nm and 0.0068 at 872 nm

  7. Biomass burning emissions of trace gases and particles in marine air at Cape Grim, Tasmania

    Science.gov (United States)

    Lawson, S. J.; Keywood, M. D.; Galbally, I. E.; Gras, J. L.; Cainey, J. M.; Cope, M. E.; Krummel, P. B.; Fraser, P. J.; Steele, L. P.; Bentley, S. T.; Meyer, C. P.; Ristovski, Z.; Goldstein, A. H.

    2015-12-01

    Biomass burning (BB) plumes were measured at the Cape Grim Baseline Air Pollution Station during the 2006 Precursors to Particles campaign, when emissions from a fire on nearby Robbins Island impacted the station. Measurements made included non-methane organic compounds (NMOCs) (PTR-MS), particle number size distribution, condensation nuclei (CN) > 3 nm, black carbon (BC) concentration, cloud condensation nuclei (CCN) number, ozone (O3), methane (CH4), carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), nitrous oxide (N2O), halocarbons and meteorology. During the first plume strike event (BB1), a 4 h enhancement of CO (max ~ 2100 ppb), BC (~ 1400 ng m-3) and particles > 3 nm (~ 13 000 cm-3) with dominant particle mode of 120 nm were observed overnight. A wind direction change lead to a dramatic reduction in BB tracers and a drop in the dominant particle mode to 50 nm. The dominant mode increased in size to 80 nm over 5 h in calm sunny conditions, accompanied by an increase in ozone. Due to an enhancement in BC but not CO during particle growth, the presence of BB emissions during this period could not be confirmed. The ability of particles > 80 nm (CN80) to act as CCN at 0.5 % supersaturation was investigated. The ΔCCN / ΔCN80 ratio was lowest during the fresh BB plume (56 ± 8 %), higher during the particle growth period (77 ± 4 %) and higher still (104 ± 3 %) in background marine air. Particle size distributions indicate that changes to particle chemical composition, rather than particle size, are driving these changes. Hourly average CCN during both BB events were between 2000 and 5000 CCN cm-3, which were enhanced above typical background levels by a factor of 6-34, highlighting the dramatic impact BB plumes can have on CCN number in clean marine regions. During the 29 h of the second plume strike event (BB2) CO, BC and a range of NMOCs including acetonitrile and hydrogen cyanide (HCN) were clearly enhanced and some enhancements in O3 were observed

  8. STANDING SHOCK INSTABILITY IN ADVECTION-DOMINATED ACCRETION FLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Le, Truong [Department of Physics, Astronomy and Geology, Berry College, Mount Berry, GA 30149 (United States); Wood, Kent S.; Wolff, Michael T. [High Energy Space Environment Branch, Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Becker, Peter A. [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States); Putney, Joy, E-mail: tle@berry.edu [Department of Physics and Engineering, Washington and Lee University, Lexington, VA 24450 (United States)

    2016-03-10

    Depending on the values of the energy and angular momentum per unit mass in the gas supplied at large radii, inviscid advection-dominated accretion flows can display velocity profiles with either preshock deceleration or preshock acceleration. Nakayama has shown that these two types of flow configurations are expected to have different stability properties. By employing the Chevalier and Imamura linearization method and the Nakayama instability boundary conditions, we discover that there are regions of parameter space where disks/shocks with outflows can be stable or unstable. In regions of instability, we find that preshock deceleration is always unstable to the zeroth mode with zero frequency of oscillation, but is always stable to the fundamental mode and overtones. Furthermore, we also find that preshock acceleration is always unstable to the zeroth mode and that the fundamental mode and overtones become increasingly less stable as the shock location moves away from the horizon when the disk half-height expands above ∼12 gravitational radii at the shock radius. In regions of stability, we demonstrate the zeroth mode to be stable for the velocity profiles that exhibit preshock acceleration and deceleration. Moreover, for models that are linearly unstable, our model suggests the possible existence of quasi-periodic oscillations (QPOs) with ratios 2:3 and 3:5. These ratios are believed to occur in stellar and supermassive black hole candidates, for example, in GRS 1915+105 and Sgr A*, respectively. We expect that similar QPO ratios also exist in regions of stable shocks.

  9. Deformation behavior of SiC particle reinforced Al matrix composites based on EMA model

    Institute of Scientific and Technical Information of China (English)

    CHENG Nan-pu; ZENG Su-min; YU Wen-bin; LIU Zhi-yi; CHEN Zhi-qian

    2007-01-01

    Effects of the matrix properties, particle size distribution and interfacial matrix failure on the elastoplastic deformation behavior in Al matrix composites reinforced by SiC particles with an average size of 5 μm and volume fraction of 12% were quantitatively calculated by using the expanded effective assumption(EMA) model. The particle size distribution naturally brings about the variation of matrix properties and the interfacial matrix failure due to the presence of SiC particles. The theoretical results coincide well with those of the experiment. The current research indicates that the load transfer between matrix and reinforcements, grain refinement in matrix, and enhanced dislocation density originated from the thermal mismatch between SiC particles and Al matrix increase the flow stress of the composites, but the interfacial matrix failure is opposite. It also proves that the load transfer, grain refinement and dislocation strengthening are the main strengthening mechanisms, and the interfacial matrix failure and ductile fracture of matrix are the dominating fracture modes in the composites. The mechanical properties of the composites strongly depend on the metal matrix.

  10. Octreotide acetate in dominant cystoid macular dystrophy.

    NARCIS (Netherlands)

    Hogewind, B.F.T.; Pieters, G.; Hoyng, C.B.

    2008-01-01

    PURPOSE: Dominant cystoid macular degeneration (DCMD) is an autosomal dominant trait of cystoid macular edema with poor visual prognosis. Until now, no efficient treatments for DCMD have been reported. The authors evaluated a somatostatin-analogue (octreotide acetate) as treatment for DCMD. METHODS:

  11. A note on generalized nonlinear diagonal dominance

    Science.gov (United States)

    Gan, Tai-Bin; Huang, Ting-Zhu; Gao, Jian

    2006-01-01

    In this paper, an open problem, proposed by A. Frommer, about nonlinear generalized diagonal dominance, is solved on some weak restriction, a counterexample is presented if such a restriction is omitted, and some new properties of nonlinear generalized diagonally dominant functions are investigated.

  12. Local surface orientation dominates haptic curvature discrimination

    NARCIS (Netherlands)

    Wijntjes, M.W.A.; Sato, A.; Hayward, V.; Kappers, A.M.L.

    2009-01-01

    Prior studies have shown that local surface orientation is a dominant source of information for haptic curvature perception in static conditions. We show that this dominance holds for dynamic touch, just as was shown earlier for static touch. Using an apparatus specifically developed for this purpos

  13. Pareto-adaptive epsilon-dominance.

    Science.gov (United States)

    Hernández-Díaz, Alfredo G; Santana-Quintero, Luis V; Coello Coello, Carlos A; Molina, Julián

    2007-01-01

    Efficiency has become one of the main concerns in evolutionary multiobjective optimization during recent years. One of the possible alternatives to achieve a faster convergence is to use a relaxed form of Pareto dominance that allows us to regulate the granularity of the approximation of the Pareto front that we wish to achieve. One such relaxed forms of Pareto dominance that has become popular in the last few years is epsilon-dominance, which has been mainly used as an archiving strategy in some multiobjective evolutionary algorithms. Despite its advantages, epsilon-dominance has some limitations. In this paper, we propose a mechanism that can be seen as a variant of epsilon-dominance, which we call Pareto-adaptive epsilon-dominance (paepsilon-dominance). Our proposed approach tries to overcome the main limitation of epsilon-dominance: the loss of several nondominated solutions from the hypergrid adopted in the archive because of the way in which solutions are selected within each box.

  14. English, Language Dominance, and Ecolinguistic Diversity Maintenance

    DEFF Research Database (Denmark)

    Phillipson, Robert; Skutnabb-Kangas, Tove

    2013-01-01

    The chapter analyses how English became dominant and the implications of the expansion of dominant languages for the linguistic and cultural ecology and biodiversity. English has expanded through the imperialist and linguicist policies of the UK, the USA and the World Bank. Key structural and ide...

  15. English, Language Dominance, and Ecolinguistic Diversity Maintenance

    DEFF Research Database (Denmark)

    Phillipson, Robert; Skutnabb-Kangas, Tove

    2017-01-01

    The chapter analyses how English became dominant and the implications of the expansion of dominant languages for the linguistic and cultural ecology and biodiversity. English has expanded through the imperialist and linguicist policies of the UK, the USA and the World Bank. Key structural and ide...

  16. Vision research: losing sight of eye dominance.

    Science.gov (United States)

    Carey, D P

    2001-10-16

    Most people prefer to use their right eye for viewing. New evidence reveals that this dominance is much more plastic than that for one hand or foot: it changes from one eye to the other depending on angle of gaze. Remarkably, sighting dominance depends on the hand being directed towards the visual target.

  17. Continental anthropogenic primary particle number emissions

    Science.gov (United States)

    Paasonen, Pauli; Kupiainen, Kaarle; Klimont, Zbigniew; Visschedijk, Antoon; Denier van der Gon, Hugo A. C.; Amann, Markus

    2016-06-01

    Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas-Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol-cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening

  18. The ion–aerosol interactions from the ion mobility and aerosol particle size distribution measurements on January 17 and February 18, 2005 at Maitri, Antarctica – A case study

    Indian Academy of Sciences (India)

    Devendraa Siingh; Vimlesh Pant; A K Kamra

    2011-08-01

    airmass over ocean. In contrast, though the ion size distributions were not much different, the aerosol size distributions did not show a dominant peak for the formation and growth of nucleation mode particles on January 17. More measurements are needed before the conclusion of this case study is generalized.

  19. Particle deposition in ventilation ducts

    Energy Technology Data Exchange (ETDEWEB)

    Sippola, Mark Raymond [Univ. of California, Berkeley, CA (United States)

    2002-09-01

    Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance and lead to secondary pollutant release within buildings. This dissertation advances the understanding of particle behavior in HVAC systems and the fates of indoor particles by means of experiments and modeling. Laboratory experiments were conducted to quantify particle deposition rates in horizontal ventilation ducts using real HVAC materials. Particle deposition experiments were conducted in steel and internally insulated ducts at air speeds typically found in ventilation ducts, 2-9 m/s. Behaviors of monodisperse particles with diameters in the size range 1-16 μm were investigated. Deposition rates were measured in straight ducts with a fully developed turbulent flow profile, straight ducts with a developing turbulent flow profile, in duct bends and at S-connector pieces located at duct junctions. In straight ducts with fully developed turbulence, experiments showed deposition rates to be highest at duct floors, intermediate at duct walls, and lowest at duct ceilings. Deposition rates to a given surface increased with an increase in particle size or air speed. Deposition was much higher in internally insulated ducts than in uninsulated steel ducts. In most cases, deposition in straight ducts with developing turbulence, in duct bends and at S-connectors at duct junctions was higher than in straight ducts with fully developed turbulence. Measured deposition rates were generally higher than predicted by published models. A model incorporating empirical equations based on the

  20. Particle deposition in ventilation ducts

    Energy Technology Data Exchange (ETDEWEB)

    Sippola, Mark R.

    2002-09-01

    Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance and lead to secondary pollutant release within buildings. This dissertation advances the understanding of particle behavior in HVAC systems and the fates of indoor particles by means of experiments and modeling. Laboratory experiments were conducted to quantify particle deposition rates in horizontal ventilation ducts using real HVAC materials. Particle deposition experiments were conducted in steel and internally insulated ducts at air speeds typically found in ventilation ducts, 2-9 m/s. Behaviors of monodisperse particles with diameters in the size range 1-16 {micro}m were investigated. Deposition rates were measured in straight ducts with a fully developed turbulent flow profile, straight ducts with a developing turbulent flow profile, in duct bends and at S-connector pieces located at duct junctions. In straight ducts with fully developed turbulence, experiments showed deposition rates to be highest at duct floors, intermediate at duct walls, and lowest at duct ceilings. Deposition rates to a given surface increased with an increase in particle size or air speed. Deposition was much higher in internally insulated ducts than in uninsulated steel ducts. In most cases, deposition in straight ducts with developing turbulence, in duct bends and at S-connectors at duct junctions was higher than in straight ducts with fully developed turbulence. Measured deposition rates were generally higher than predicted by published models. A model incorporating empirical equations based on

  1. Modelling dominance in a flexible intercross analysis

    Directory of Open Access Journals (Sweden)

    Besnier Francois

    2009-06-01

    Full Text Available Abstract Background The aim of this paper is to develop a flexible model for analysis of quantitative trait loci (QTL in outbred line crosses, which includes both additive and dominance effects. Our flexible intercross analysis (FIA model accounts for QTL that are not fixed within founder lines and is based on the variance component framework. Genome scans with FIA are performed using a score statistic, which does not require variance component estimation. Results Simulations of a pedigree with 800 F2 individuals showed that the power of FIA including both additive and dominance effects was almost 50% for a QTL with equal allele frequencies in both lines with complete dominance and a moderate effect, whereas the power of a traditional regression model was equal to the chosen significance value of 5%. The power of FIA without dominance effects included in the model was close to those obtained for FIA with dominance for all simulated cases except for QTL with overdominant effects. A genome-wide linkage analysis of experimental data from an F2 intercross between Red Jungle Fowl and White Leghorn was performed with both additive and dominance effects included in FIA. The score values for chicken body weight at 200 days of age were similar to those obtained in FIA analysis without dominance. Conclusion We have extended FIA to include QTL dominance effects. The power of FIA was superior, or similar, to standard regression methods for QTL effects with dominance. The difference in power for FIA with or without dominance is expected to be small as long as the QTL effects are not overdominant. We suggest that FIA with only additive effects should be the standard model to be used, especially since it is more computationally efficient.

  2. Particle physics

    CERN Document Server

    Kennedy, Eugene

    2012-01-01

    Stimulated by the Large Hadron Collider and the search for the elusive Higgs Boson, interest in particle physics continues at a high level among scientists and the general public. This book includes theoretical aspects, with chapters outlining the generation model and a charged Higgs boson model as alternative scenarios to the Standard Model. An introduction is provided to postulated axion photon interactions and associated photon dispersion in magnetized media. The complexity of particle physics research requiring the synergistic combination of theory, hardware and computation is described in terms of the e-science paradigm. The book concludes with a chapter tackling potential radiation hazards associated with extremely weakly interacting neutrinos if produced in copious amounts with future high-energy muon-collider facilities.

  3. Active particles

    CERN Document Server

    Degond, Pierre; Tadmor, Eitan

    2017-01-01

    This volume collects ten surveys on the modeling, simulation, and applications of active particles using methods ranging from mathematical kinetic theory to nonequilibrium statistical mechanics. The contributing authors are leading experts working in this challenging field, and each of their chapters provides a review of the most recent results in their areas and looks ahead to future research directions. The approaches to studying active matter are presented here from many different perspectives, such as individual-based models, evolutionary games, Brownian motion, and continuum theories, as well as various combinations of these. Applications covered include biological network formation and network theory; opinion formation and social systems; control theory of sparse systems; theory and applications of mean field games; population learning; dynamics of flocking systems; vehicular traffic flow; and stochastic particles and mean field approximation. Mathematicians and other members of the scientific commu...

  4. Particle astrophysics

    CERN Document Server

    Krauss, Lawrence M

    1997-01-01

    Astrophysics and cosmology provide fundamental testing grounds for many ideas in elementary particle physics, and include potential probes which are well beyond the range of current or even planned accelerators. In this series of 3 lectures, I will give and overview of existing constraints, and a discussion of the potential for the future. I will attempt whenever possible to demonstrate the connection between accelerator-based physics and astrophysicas/cosmology. The format of the kectures will be to examine observables from astrophysics, and explore how these can be used to constrain particle physics. Tentatively, lecture 1 will focus on the age and mass density of the universe and galaxy. Lecture 2 will focus on stars, stellar evolution, and the abundance of light elements. Lecture 3 will focus on various cosmic diffuse backgrounds, including possibly matter, photons, neutrinos and gravitational waves.

  5. Observing thermomagnetic stability of nonideal magnetite particles

    DEFF Research Database (Denmark)

    Almeida, Trevor P.; Kasama, Takeshi; Muxworthy, Adrian R.

    2014-01-01

    The thermomagnetic behavior of remanence-induced magnetite (Fe3O4) particles in the pseudo-single-domain (PSD) size range (similar to 0.1-10 mu m), which dominate the magnetic signature of many rock lithologies, is investigated using off-axis electron holography. Construction of magnetic induction...... of the Fe3O4 grain, in this instance, remains thermally stable close to its unblocking temperature and exhibits a similar in-plane remanent state upon cooling; i.e., the particle is effectively behaving like a uniaxial single-domain particle to temperatures near T-C. Such particles are thought to be robust...

  6. Few-mode fibers for mode division multiplexing transmission

    Science.gov (United States)

    Kubota, Hirokazu; Morioka, Toshio

    2012-01-01

    A study is presented of the fiber properties needed to achieve 10-mode multiplexing transmission. A combination of MIMO processing with optical LP mode separation is proposed to prevent the need for massive MIMO computation. The impact of mode crosstalk, differential mode delay, and the mode dependent loss of the few-mode fibers on mode multiplexing are discussed.

  7. Particle encapsulation

    OpenAIRE

    Sun, Xiaobin

    2000-01-01

    Several engineering processes are powder based, ranging from food processing to engineering ceramic and composite production. In most of these processes, powders of different composition are mixed together in order to produce the final product, and this combining of powders of different density, shape, and surface properties is often very difficult. Mixtures may be quite inhomogeneous. This research focuses on a method of avoiding such problems, by coating individual particles of one material...

  8. Martian Particle

    Science.gov (United States)

    2008-01-01

    This image of Martian soil was taken by the Phoenix Lander's atomic force microscope on Sol 74 of the mission, which began on May 25, 2008. This image of a flat, smooth-surfaced particle is consistent with the appearance of soil from Earth containing the mineral phyllosilicate. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

  9. Helium, Iron and Electron Particle Transport and Energy Transport Studies on the TFTR Tokamak

    Science.gov (United States)

    Synakowski, E. J.; Efthimion, P. C.; Rewoldt, G.; Stratton, B. C.; Tang, W. M.; Grek, B.; Hill, K. W.; Hulse, R. A.; Johnson, D .W.; Mansfield, D. K.; McCune, D.; Mikkelsen, D. R.; Park, H. K.; Ramsey, A. T.; Redi, M. H.; Scott, S. D.; Taylor, G.; Timberlake, J.; Zarnstorff, M. C. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Kissick, M. W. (Wisconsin Univ., Madison, WI (United States))

    1993-03-01

    Results from helium, iron, and electron transport on TFTR in L-mode and Supershot deuterium plasmas with the same toroidal field, plasma current, and neutral beam heating power are presented. They are compared to results from thermal transport analysis based on power balance. Particle diffusivities and thermal conductivities are radially hollow and larger than neoclassical values, except possibly near the magnetic axis. The ion channel dominates over the electron channel in both particle and thermal diffusion. A peaked helium profile, supported by inward convection that is stronger than predicted by neoclassical theory, is measured in the Supershot The helium profile shape is consistent with predictions from quasilinear electrostatic drift-wave theory. While the perturbative particle diffusion coefficients of all three species are similar in the Supershot, differences are found in the L-Mode. Quasilinear theory calculations of the ratios of impurity diffusivities are in good accord with measurements. Theory estimates indicate that the ion heat flux should be larger than the electron heat flux, consistent with power balance analysis. However, theoretical values of the ratio of the ion to electron heat flux can be more than a factor of three larger than experimental values. A correlation between helium diffusion and ion thermal transport is observed and has favorable implications for sustained ignition of a tokamak fusion reactor.

  10. Helium, iron and electron particle transport and energy transport studies on the TFTR tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Synakowski, E.J.; Efthimion, P.C.; Rewoldt, G.; Stratton, B.C.; Tang, W.M.; Grek, B.; Hill, K.W.; Hulse, R.A.; Johnson, D.W.; Mansfield, D.K.; McCune, D.; Mikkelsen, D.R.; Park, H.K.; Ramsey, A.T.; Redi, M.H.; Scott, S.D.; Taylor, G.; Timberlake, J.; Zarnstorff, M.C. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Kissick, M.W. [Wisconsin Univ., Madison, WI (United States)

    1993-03-01

    Results from helium, iron, and electron transport on TFTR in L-mode and Supershot deuterium plasmas with the same toroidal field, plasma current, and neutral beam heating power are presented. They are compared to results from thermal transport analysis based on power balance. Particle diffusivities and thermal conductivities are radially hollow and larger than neoclassical values, except possibly near the magnetic axis. The ion channel dominates over the electron channel in both particle and thermal diffusion. A peaked helium profile, supported by inward convection that is stronger than predicted by neoclassical theory, is measured in the Supershot The helium profile shape is consistent with predictions from quasilinear electrostatic drift-wave theory. While the perturbative particle diffusion coefficients of all three species are similar in the Supershot, differences are found in the L-Mode. Quasilinear theory calculations of the ratios of impurity diffusivities are in good accord with measurements. Theory estimates indicate that the ion heat flux should be larger than the electron heat flux, consistent with power balance analysis. However, theoretical values of the ratio of the ion to electron heat flux can be more than a factor of three larger than experimental values. A correlation between helium diffusion and ion thermal transport is observed and has favorable implications for sustained ignition of a tokamak fusion reactor.

  11. Physical and chemical properties of pollution aerosol particles transported from North America to Greenland as measured during the POLARCAT summer campaign

    Directory of Open Access Journals (Sweden)

    B. Quennehen

    2011-04-01

    Full Text Available Within the framework of the POLARCAT-France campaign, aerosol physical, chemical and optical properties over Greenland were measured onboard the French ATR-42 research aircraft. The Lagrangian particle dispersion model FLEXPART was used to determine air mass origins. The study focuses particularly on the characterization of air masses transported from the North American continent. Air masses that picked up emissions from Canadian and Alaskan boreal forest fires as well as from the cities on the American east coast were identified and selected for a detailed study. Measurements of CO concentrations, aerosol chemical composition, aerosol size distributions, aerosol volatile fractions and aerosol light absorption (mainly from black carbon are used in order to study the relationship between CO enhancement, ageing of the air masses, aerosol particle concentrations and size distributions. Aerosol size distributions are in good agreement with previous studies, even though, wet scavenging potentially occurred along the pathway between the emission sources and Greenland leading to lower concentrations in the aerosol accumulation mode. The measured aerosol size distributions show a significant enhancement of Aitken mode particles. It is demonstrated that the Aitken mode is largely composed of black carbon, while the accumulation mode is more dominated by organics, as deduced from aerosol mass spectrometric AMS and aerosol volatility measurements. Overall, during the campaign rather small amounts of black carbon from the North American continent were transported towards Greenland. An important finding given the potential climate impacts of black carbon in the Arctic.

  12. FEM solutions for plane stress mode-I and mode-II cracks in strain gradient plasticity

    Institute of Scientific and Technical Information of China (English)

    邱信明; 郭田福; 黄克智

    2000-01-01

    The strain gradient plasticity theory is used to investigate the crack-tip field in a power law hardening material. Numerical solutions are presented for plane-stress mode I and mode II cracks under small scale yielding conditions. A comparison is made with the existing asymptotic fields. It is found that the size of the dominance zone for the near-tip asymptotic field, recently obtained by Chen et al., is on the order 5% of the intrinsic material length I. Remote from the dominance zone, the computed stress field tends to be the classical HRR field. Within the plastic zone only force-stress dominated solution is found for either mode I or mode II crack.

  13. Nonlinear dynamics of electrons interacting with oblique whistler mode chorus in the magnetosphere

    Science.gov (United States)

    Hsieh, Yi-Kai; Omura, Yoshiharu

    2017-01-01

    We perform test particle simulations for relativistic electrons interacting with a whistler mode chorus packet propagating at oblique angles. By confirming that the energy transport of oblique lower band chorus is nearly along the ambient magnetic field, we apply the gyroaveraging method in calculating equations of motion of electrons. We trace evolution of a delta function of relativistic electrons in a phase space of kinetic energy and equatorial pitch angle and obtain numerical Green's functions of the chorus wave-particle interactions. Examining the Green's functions in a wide range of kinetic energies, we find that Landau resonance can accelerate MeV electrons efficiently and that higher nth resonances such as n =- 1 and n = 2 also contribute to acceleration of electrons at high equatorial pitch angles (˜70°) and high energies (˜2 MeV). We investigate the rate of energy gain of the cyclotron resonance acceleration and the Landau resonance acceleration and find that the perpendicular component of wave electric field dominates both accelerations for MeV electrons. Furthermore, the proximity between the parallel components of Vp and Vg of oblique whistler mode waves and the nonlinear trapping condition make the interaction time of Landau resonance much longer than that of n = 1 cyclotron resonance, resulting in efficient acceleration of MeV electrons.

  14. Micromagnetic simulation of a ferromagnetic particle

    Directory of Open Access Journals (Sweden)

    Ntallis N.

    2014-01-01

    Full Text Available In this work, the magnetic behaviour of a ferromagnetic particle has been investigated by means of micromagnetic modelling, using the Finite Element Method. The simulations were performed on an ellipsoidal particle with uniaxial magnetocrystalline anisotropy by varying the anisotropy constant, the shape and dimensions of the particle. The results indicate the critical particle size for different reversal modes. Above a critical size the formation and motion of domain walls is clearly observed. The associated nucleation and coercive fields are estimated from the demagnetization curves.

  15. VH mode accessibility and global H-mode properties in previous and present JET configurations

    Energy Technology Data Exchange (ETDEWEB)

    Jones, T.T.C.; Ali-Arshad, S.; Bures, M.; Christiansen, J.P.; Esch, H.P.L. de; Fishpool, G.; Jarvis, O.N.; Koenig, R.; Lawson, K.D.; Lomas, P.J.; Marcus, F.B.; Sartori, R.; Schunke, B.; Smeulders, P.; Stork, D.; Taroni, A.; Thomas, P.R.; Thomsen, K. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-07-01

    In JET VH modes, there is a distinct confinement transition following the cessation of ELMs, observed in a wide variety of tokamak operating conditions, using both NBI and ICRF heating methods. Important factors which influence VH mode accessibility such as magnetic configuration and vessel conditions have been identified. The new JET pumped divertor configuration has much improved plasma shaping control and power and particle exhaust capability and should permit exploitation of plasmas with VH confinement properties over an even wider range of operating regimes, particularly at high plasma current; first H-modes have been obtained in the 1994 JET operating period and initial results are reported. (authors). 7 refs., 6 figs.

  16. Electroconvulsive therapy and determination of cerebral dominance.

    Science.gov (United States)

    Dragovic, Milan; Allet, Lindsay; Janca, Aleksandar

    2004-08-12

    Electroconvulsive therapy (ECT) often results in a number of short- and long-time side effects including memory impairment for past and current events, which can last for several months after ECT treatment. It has been suggested that unilateral ECT (uECT) with electrodes placed over the non-dominant (typically right) hemisphere significantly reduces side effects, especially memory disturbances. It is important to note that cerebral dominance equates to speech dominance and avoiding this area of the brain also reduces speech dysfunction after ECT. Traditionally, the routine clinical determination of cerebral dominance has been through the assessment of hand, foot and eye dominance, which is an easy and inexpensive approach that, however, does not ensure accuracy. This review of literature on different methods and techniques for determination of cerebral dominance and provides evidence that functional transcranial Doppler sonography (fTCD) represents a valid and safe alternative to invasive techniques for identifying speech lateralisation. It can be concluded that fTCD, notwithstanding its costs, could be used as a standard procedure prior to uECT treatment to determine cerebral dominance, thereby further reducing cognitive side-effects of ECT and possibly making it more acceptable to both patients and clinicians.

  17. Self-amplitude and self-phase modulation of the charcoal mode-locked erbium-doped fiber lasers.

    Science.gov (United States)

    Lin, Yung-Hsiang; Lo, Jui-Yung; Tseng, Wei-Hsuan; Wu, Chih-I; Lin, Gong-Ru

    2013-10-21

    With the intra-cavity nano-scale charcoal powder based saturable absorber, the 455-fs passive mode-locking of an L-band erbium-doped fiber laser (EDFL) is demonstrated. The size reduction of charcoal nano-particle is implemented with a simple imprinting-exfoliation-wiping method, which assists to increase the transmittance up to 0.91 with corresponding modulation depth of 26%. By detuning the power gain from 17 to 21 dB and cavity dispersion from -0.004 to -0.156 ps² of the EDFL, the shortening of mode-locked pulsewidth from picosecond to sub-picosecond by the transformation of the pulse forming mechanism from self-amplitude modulation (SAM) to the combining effect of self-phase modulation (SPM) and group delay dispersion (GDD) is observed. A narrower spectrum with 3-dB linewidth of 1.83-nm is in the SAM case, whereas the spectral linewidth broadens to 5.86 nm with significant Kelly sideband pair can be observed if the EDFL enters into the SPM regime. The mode-locking mechanism transferred from SAM to SPM/GDD dominates the pulse shortening procedure in the EDFL, whereas the intrinsic defects in charcoal nano-particle only affect the pulse formation at initial stage. The minor role of the saturable absorber played in the EDFL cavity with strongest SPM is observed.

  18. Exposure to fine particulate, black carbon, and particle number concentration in transportation microenvironments

    Science.gov (United States)

    Morales Betancourt, R.; Galvis, B.; Balachandran, S.; Ramos-Bonilla, J. P.; Sarmiento, O. L.; Gallo-Murcia, S. M.; Contreras, Y.

    2017-05-01

    This research determined intake dose of fine particulate matter (PM2.5), equivalent black carbon (eBC), and number of sub-micron particles (Np) for commuters in Bogotá, Colombia. Doses were estimated through measurements of exposure concentration, a surrogate of physical activity, as well as travel times and speeds. Impacts of travel mode, traffic load, and street configuration on dose and exposure were explored. Three road segments were selected because of their different traffic loads and composition, and dissimilar street configuration. The transport modes considered include active modes (walking and cycling) and motorized modes (bus, car, taxi, and motorcycle). Measurements were performed simultaneously in the available modes at each road segment. High average eBC concentrations were observed throughout the campaign, ranging from 20 to 120 μgm-3 . Commuters in motorized modes experienced significantly higher exposure concentrations than pedestrians and bicyclists. The highest average concentrations of PM2.5, eBC , and Np were measured inside the city's Bus Rapid Transit (BRT) system vehicles. Pedestrians and bicycle users in an open street configuration were exposed to the lowest average concentrations of PM2.5 and eBC , six times lower than those experienced by commuters using the BRT in the same street segment. Pedestrians experienced the highest particulate matter intake dose in the road segments studied, despite being exposed to lower concentrations than commuters in motorized modes. Average potential dose of PM2.5 and eBC per unit length traveled were nearly three times higher for pedestrians in a street canyon configuration compared to commuters in public transport. Slower travel speed and elevated inhalation rates dominate PM dose for pedestrians. The presence of dedicated bike lanes on sidewalks has a significant impact on reducing the exposure concentration for bicyclists compared to those riding in mixed traffic lanes. This study proposes a simple

  19. Mode Transitions in Magnetically Shielded Hall Effect Thrusters

    Science.gov (United States)

    Sekerak, Michael J.; Longmier, Benjamin W.; Gallimore, Alec D.; Huang, Wensheng; Kamhawi, Hani; Hofer, Richard R.; Jorns, Benjamin A.; Polk, James E.

    2014-01-01

    A mode transition study is conducted in magnetically shielded thrusters where the magnetic field magnitude is varied to induce mode transitions. Three different oscillatory modes are identified with the 20-kW NASA-300MS-2 and the 6-kW H6MS: Mode 1) global mode similar to unshielded thrusters at low magnetic fields, Mode 2) cathode oscillations at nominal magnetic fields, and Mode 3) combined spoke, cathode and breathing mode oscillations at high magnetic fields. Mode 1 exhibits large amplitude, low frequency (1-10 kHz), breathing mode type oscillations where discharge current mean value and oscillation amplitude peak. The mean discharge current is minimized while thrust-to-power and anode efficiency are maximized in Mode 2, where higher frequency (50-90 kHz), low amplitude, cathode oscillations dominate. Thrust is maximized in Mode 3 and decreases by 5-6% with decreasing magnetic field strength. The presence or absence of spokes and strong cathode oscillations do not affect each other or discharge current. Similar to unshielded thrusters, mode transitions and plasma oscillations affect magnetically shielded thruster performance and should be characterized during system development.

  20. Radiation in Particle Simulations

    Energy Technology Data Exchange (ETDEWEB)

    More, R; Graziani, F; Glosli, J; Surh, M

    2010-11-19

    Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of megabars to thousands of gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present four methods that attempt a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The first method applies the Lienard-Weichert solution of Maxwell's equations for a classical particle whose motion is assumed to be known. The second method expands the electromagnetic field in normal modes (planewaves in a box with periodic boundary-conditions) and solves the equation for wave amplitudes coupled to the particle motion. The third method is a hybrid molecular dynamics/Monte Carlo (MD/MC) method which calculates radiation emitted or absorbed by electron-ion pairs during close collisions. The fourth method is a generalization of the third method to include small clusters of particles emitting radiation during close encounters: one electron simultaneously hitting two ions, two electrons simultaneously hitting one ion, etc. This approach is inspired by the virial expansion method of equilibrium statistical mechanics. Using a combination of these methods we believe it is possible to do atomic-scale particle

  1. The roles of sulfuric acid in new particle formation and growth in the mega-city of Beijing

    Directory of Open Access Journals (Sweden)

    D. L. Yue

    2010-05-01

    Full Text Available Simultaneous measurements of gaseous sulfuric acid and particle number size distributions were performed to investigate aerosol nucleation and growth during CAREBeijing-2008. The analysis of the measured aerosols and sulfuric acid with an aerosol dynamic model shows the dominant role of sulfuric acid in new particle formation (NPF process but also in the subsequent growth in Beijing. Based on the data of twelve NPF events, the average formation rates (2–13 cm−3 s−1 show a linear correlation with the sulfuric acid concentrations (R2=0.85. Coagulation seems to play a significant role in reducing the number concentration of nucleation mode particles with the ratio of the coagulation loss to formation rate being 0.41±0.16. The apparent growth rates vary from 3 to 11 nm h−1. Condensation of sulfuric acid and its subsequent neutralization by ammonia and coagulation contribute to the apparent particle growth on average 45±18% and 34±17%, respectively. The 30% higher concentration of sulfate than organic compounds in particles during the seven sulfur-rich NPF events but 20% lower concentration of sulfate during the five sulfur-poor type suggest that organic compounds are an important contributor to the growth of the freshly nucleated particles, especially during the sulfur-poor cases.

  2. Predictors of dominance in male Betta splendens.

    Science.gov (United States)

    Bronstein, P M

    1985-03-01

    The formation of dominance/subordinancy relations in pairs of male Siamese fighting fish was examined in six experiments. Dominant animals typically were those fish that built the largest nests and that attacked an image of a live, displaying male most intensely prior to combat. However, pretest performance on an operant task and reaction to an animal's own mirror image were not useful predictors of subsequent dominance. These findings are consistent with the suggestion that domesticated Bettas have a territorial social strategy that includes both nest-building and fighting behaviors.

  3. Height Estimates for Equidimensional Dominant Rational Maps

    CERN Document Server

    Silverman, Joseph H

    2009-01-01

    Let F : W --> V be a dominant rational map between quasi-projective varieties of the same dimension. We give two proofs that h_V(F(P)) >> h_W(P) for all points P in a nonempty Zariski open subset of W. For dominant rational maps F : P^n --> P^n, we give a uniform estimate in which the implied constant depends only on n and the degree of F. As an application, we prove a specialization theorem for equidimensional dominant rational maps to semiabelian varieties, providing a complement to Habegger's recent theorem on unlikely intersections.

  4. Excessive prices as abuse of dominance?

    DEFF Research Database (Denmark)

    la Cour, Lisbeth; Møllgaard, Peter

    2007-01-01

    In previous research, we found that the sole Danish producer of cement holds a dominant position in the Danish market for (grey) cement. We are able to identify an inelastic long-run demand relation that would seem to permit the exercise of market power. We aim to establish whether the dominant...... firm abused its position by charging excessive prices. We also test whether tightening of the Danish competition act has altered the pricing behaviour on the market. We discuss our results in the light of a Danish competition case against the dominant cement producer that was abandoned by the authority...

  5. Total dominator chromatic number of a graph

    Directory of Open Access Journals (Sweden)

    Adel P. Kazemi

    2015-06-01

    Full Text Available Given a graph $G$, the total dominator coloring problem seeks a proper coloring of $G$ with the additional property that every vertex in the graph is adjacent to all vertices of a color class. We seek to minimize the number of color classes. We initiate to study this problem on several classes of graphs, as well as finding general bounds and characterizations. We also compare the total dominator chromatic number of a graph with the chromatic number and the total domination number of it.

  6. Streaming tearing mode

    Science.gov (United States)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  7. Mode selection laser

    DEFF Research Database (Denmark)

    2014-01-01

    The invention relates to a semiconductor mode selection laser, particularly to a VCSEL laser (200) having mode selection properties. The mode selection capability of the laser is achieved by configuring one of the reflectors (15,51) in the resonance cavity so that a reflectivity of the reflector...... (15) varies spatially in one dimension or two dimensions. Accordingly, the reflector (15) with spatially varying reflectivity is part both of the resonance cavity and the mode selection functionality of the laser. A plurality of the lasers configured with different mode selectors, i.e. different...... spatial reflector variations, may be combined to generate a laser beam containing a plurality of orthogonal modes. The laser beam may be injected into a few- mode optical fiber, e.g. for the purpose of optical communication. The VCSEL may have intra-cavity contacts (31,37) and a Tunnel junction (33...

  8. Streaming tearing mode

    Science.gov (United States)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  9. Sub-micron atmospheric aerosols in the surroundings of Marseille and Athens: physical characterization and new particle formation

    Science.gov (United States)

    Petäjä, T.; Kerminen, V.-M.; Dal Maso, M.; Junninen, H.; Koponen, I. K.; Hussein, T.; Aalto, P. P.; Andronopoulos, S.; Robin, D.; Hämeri, K.; Bartzis, J. G.; Kulmala, M.

    2007-05-01

    The properties of atmospheric aerosol particles in Marseille and Athens were investigated. The studies were performed in Marseille, France, during July 2002 and in Athens, Greece, during June 2003. The aerosol size distribution and the formation and growth rates of newly formed particles were characterized using Differential Mobility Particle Sizers. Hygroscopic properties were observed using a Hygroscopic Tandem Differential Mobility Analyzer setup. During both campaigns, the observations were performed at suburban, almost rural sites, and the sites can be considered to show general regional background behavior depending on the wind direction. At both sites there were clear pattern for both aerosol number concentration and hygroscopic properties. Nucleation mode number concentration increased during the morning hours indicating new particle formation, which was observed during more than 30% of the days. The observed formation rate was typically more than 1 cm-3 s-1, and the growth rate was between 1.2-9.9 nm h-1. Based on hygroscopicity measurements in Athens, the nucleation mode size increase was due to condensation of both water insoluble and water soluble material. However, during a period of less anthropogenic influence, the growth was to a larger extent due to water insoluble components. When urban pollution was more pronounced, growth due to condensation of water soluble material dominated.

  10. The Sound of Dominance: Vocal Precursors of Perceived Dominance during Interpersonal Influence.

    Science.gov (United States)

    Tusing, Kyle James; Dillard, James Price

    2000-01-01

    Determines the effects of vocal cues on judgments of dominance in an interpersonal influence context. Indicates that mean amplitude and amplitude standard deviation were positively associated with dominance judgments, whereas speech rate was negatively associated with dominance judgments. Finds that mean fundamental frequency was positively…

  11. Initial value problem of the toroidal ion temperature gradient mode

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, T.; Sugama, H.; Kanno, R.; Okamoto, M. [National Inst. for Fusion Science, Toki, Gifu (Japan); Horton, W.

    1998-06-01

    The initial value problem of the toroidal ion temperature gradient mode is studied based on the Laplace transform of the ion gyrokinetic equation and the electron Boltzmann relation with the charge neutrality condition. Due to the toroidal magnetic drift, the Laplace-transformed density and potential perturbations have a branch cut as well as poles on the complex-frequency plane. The inverse Laplace transform shows that the temporal evolution of the density and potential perturbations consists of the normal modes and the continuum mode, which correspond to contributions from the poles and the branch cut, respectively. The normal modes have exponential time dependence with the eigenfrequencies determined by the dispersion relation while the continuum mode shows power-law decay oscillation. For the stable case, the long-time asymptotic behavior of the potential and density perturbations is dominated by the continuum mode which decays slower than the normal modes. (author)

  12. Strong and tunable mode coupling in carbon nanotube resonators

    Science.gov (United States)

    Castellanos-Gomez, Andres; Meerwaldt, Harold B.; Venstra, Warner J.; van der Zant, Herre S. J.; Steele, Gary A.

    2012-07-01

    The nonlinear interaction between two mechanical resonances of the same freely suspended carbon nanotube resonator is studied. We find that, in the Coulomb-blockade regime, the nonlinear modal interaction is dominated by single-electron-tunneling processes and that the mode-coupling parameter can be tuned with the gate voltage, allowing both mode-softening and mode-stiffening behaviors. This is in striking contrast to tension-induced mode coupling in strings where the coupling parameter is positive and gives rise to a stiffening of the mode. The strength of the mode coupling in carbon nanotubes in the Coulomb-blockade regime is observed to be 6 orders of magnitude larger than the mechanical-mode coupling in micromechanical resonators.

  13. Modeling radiation in particle clouds: On the importance of inter-particle radiation for pulverized solid fuel combustion

    CERN Document Server

    Haugen, Nils Erland L

    2014-01-01

    The importance of inter-particle radiation for clusters of gray and diffuse particles is investigated. The radiative cooling of each individual particle is found to vary strongly with its position in the cluster, and a mean radiative particle cooling term is proposed for single particle simulations of particle clusters or for high detail simulation, like Direct Numerical Simulations of small sub-volumes of large clusters of particles. Radiative cooling is shown to be important both for furnaces for coal gasification and coal combustion. Broadening the particle size distribution is found to have just a minor effect on the radiative particle cooling. This is particularly the case for large and dense particle clusters where there is essentially no effect of size distribution broadening at all. For smaller and more dilute particle clusters, the effect of distribution broadening is clear but still not dominant.

  14. Long-lived and unstable modes of Brownian suspensions in microchannels

    CERN Document Server

    Khoshnood, Atefeh

    2012-01-01

    We investigate the stability of the pressure-driven, low-Reynolds flow of Brownian suspensions with spherical particles in microchannels. We find two general families of stable/unstable modes: (i) degenerate modes with symmetric and anti-symmetric patterns; (ii) single modes that are either symmetric or anti-symmetric. The concentration profiles of degenerate modes have strong peaks near the channel walls, while single modes diminish there. Once excited, both families would be detectable through high-speed imaging. We find that unstable modes occur in concentrated suspensions whose velocity profiles are sufficiently flattened near the channel centreline. The patterns of growing unstable modes suggest that they are triggered due to Brownian migration of particles between the central bulk that moves with an almost constant velocity, and highly-sheared low-velocity region near the wall. Modes are amplified because shear-induced diffusion cannot efficiently disperse particles from the cavities of the perturbed ve...

  15. Particle Mechanics

    CERN Document Server

    Collinson, Chris

    1995-01-01

    * Assumes no prior knowledge* Adopts a modelling approach* Numerous tutorial problems, worked examples and exercises included* Elementary topics augmented by planetary motion and rotating framesThis text provides an invaluable introduction to mechanicsm confining attention to the motion of a particle. It begins with a full discussion of the foundations of the subject within the context of mathematical modelling before covering more advanced topics including the theory of planetary orbits and the use of rotating frames of reference. Truly introductory , the style adoped is perfect for those u

  16. Edge-localized mode avoidance and pedestal structure in I-mode plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Walk, J. R., E-mail: jrwalk@psfc.mit.edu; Hughes, J. W.; Hubbard, A. E.; Terry, J. L.; Whyte, D. G.; White, A. E.; Baek, S. G.; Reinke, M. L.; Theiler, C.; Churchill, R. M.; Rice, J. E. [MIT Plasma Science and Fusion Center, Cambridge, MA 02139-4307 (United States); Snyder, P. B.; Osborne, T. [General Atomics, San Diego, CA 92186-5608 (United States); Dominguez, A [Princeton Plasma Physics Laboratory, Princeton, NJ 08543-0451 (United States); Cziegler, I. [UCSD Center for Momentum Transport and Flow Organization, La Jolla, CA 92093-0417 (United States)

    2014-05-15

    I-mode is a high-performance tokamak regime characterized by the formation of a temperature pedestal and enhanced energy confinement, without an accompanying density pedestal or drop in particle and impurity transport. I-mode operation appears to have naturally occurring suppression of large Edge-Localized Modes (ELMs) in addition to its highly favorable scalings of pedestal structure and overall performance. Extensive study of the ELMy H-mode has led to the development of the EPED model, which utilizes calculations of coupled peeling-ballooning MHD modes and kinetic-ballooning mode (KBM) stability limits to predict the pedestal structure preceding an ELM crash. We apply similar tools to the structure and ELM stability of I-mode pedestals. Analysis of I-mode discharges prepared with high-resolution pedestal data from the most recent C-Mod campaign reveals favorable pedestal scalings for extrapolation to large machines—pedestal temperature scales strongly with power per particle P{sub net}/n{sup ¯}{sub e}, and likewise pedestal pressure scales as the net heating power (consistent with weak degradation of confinement with heating power). Matched discharges in current, field, and shaping demonstrate the decoupling of energy and particle transport in I-mode, increasing fueling to span nearly a factor of two in density while maintaining matched temperature pedestals with consistent levels of P{sub net}/n{sup ¯}{sub e}. This is consistent with targets for increased performance in I-mode, elevating pedestal β{sub p} and global performance with matched increases in density and heating power. MHD calculations using the ELITE code indicate that I-mode pedestals are strongly stable to edge peeling-ballooning instabilities. Likewise, numerical modeling of the KBM turbulence onset, as well as scalings of the pedestal width with poloidal beta, indicates that I-mode pedestals are not limited by KBM turbulence—both features identified with the trigger for large ELMs

  17. Outside finance, dominant investors and strategic transparency

    NARCIS (Netherlands)

    E.C. Perotti; E.-L. von Thadden

    2000-01-01

    This paper studies optimal financial contracts and product market competition under a strategic transparency decision. When firms seeking outside finance resort to actively monitored debt in order to commit against opportunistic behaviour, the dominant lender can influence corporate transparency. Mo

  18. A dynamic domination problem in trees

    Directory of Open Access Journals (Sweden)

    William Klostermeyer

    2015-12-01

    Full Text Available We consider a dynamic domination problem for graphs in which an infinite sequence of attacks occur at vertices with guards and the guard at the attacked vertex is required to vacate the vertex by moving to a neighboring vertex with no guard. Other guards are allowed to move at the same time, and before and after each attack and the resulting guard movements, the vertices containing guards form a dominating set of the graph. The minimum number of guards that can successfully defend the graph against such an arbitrary sequence of attacks is the m-eviction number. This parameter lies between the domination and independence numbers of the graph. We characterize the classes of trees for which the m-eviction number equals the domination number and the independence number, respectively.

  19. States on sharply dominating effect algebras

    Institute of Scientific and Technical Information of China (English)

    Zdenka RIE(C)ANOV(A); WU JunDe

    2008-01-01

    We prove that sharply dominating Archimedean atomic lattice effect algebras can be characterized by the property called basic decomposition of elements. As an application we prove the state smearing theorem for these effect algebras.

  20. States on sharply dominating effect algebras

    Institute of Scientific and Technical Information of China (English)

    Zdenka; RIE■ANOV

    2008-01-01

    We prove that sharply dominating Archimedean atomic lattice effect algebras can be characterized by the property called basic decomposition of elements.As an application we prove the state smearing theorem for these effect algebras.