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Sample records for accumulation mode particle

  1. "DIAGNOSTIC" PULSE FOR SINGLE-PARTICLE-LIKE BEAM POSITION MEASUREMENTS DURING ACCUMULATION/PRODUCTION MODE IN THE LOS ALAMOS PROTON STORAGE RING

    SciTech Connect

    Kolski, Jeffrey S.; Baily, Scott A.; Bjorklund, Eric A.; Bolme, Gerald O.; Hall, Michael J.; Kwon, Sung I.; Martinez, Martin P.; Prokop, Mark S.; Shelley, Fred E. Jr.; Torrez, Phillip A.

    2012-05-14

    Beam position monitors (BPMs) are the primary diagnostic in the Los Alamos Proton Storage Ring (PSR). When injecting one turn, the transversemotion is approximated as a single particle with initial betatron position and angle {rvec x}{sub 0} and {rvec x}'{sub 0}. With single-turn injection, we fit the betatron tune, closed orbit (CO), and injection offset ({rvec x}{sub 0} and {rvec x}'{sub 0} at the injection point) to the turn-by-turn beam position. In production mode, we accumulate multiple turns, the transverse phase space fills after 5 injections (horizontal and vertical fractional betatron tunes {approx}0.2) resulting in no coherent betatron motion, and only the CO may be measured. The injection offset, which determines the accumulated beam size and is very sensitive to steering upstream of the ring, is not measurable in production mode. We describe our approach and ongoing efforts to measure the injection offset during production mode by injecting a 'diagnostic' pulse {approx}50 {micro}s after the accumulated beam is extracted. We also study the effects of increasing the linac RF gate length to accommodate the diagnostic pulse on the production beam position, transverse size, and loss.

  2. Indoor/outdoor relationships of quasi-ultrafine, accumulation and coarse mode particles in school environments in Barcelona: chemical composition and sources

    NASA Astrophysics Data System (ADS)

    Viana, M.; Rivas, I.; Querol, X.; Alastuey, A.; Sunyer, J.; Álvarez-Pedrerol, M.; Bouso, L.; Sioutas, C.

    2013-12-01

    The mass concentration, chemical composition and sources of quasi-ultrafine (quasi-UFP, PM0.25), accumulation (PM0.25-2.5) and coarse mode (PM2.5-10) particles were determined in indoor and outdoor air at 39 schools in Barcelona (Spain). Quasi-UFP mass concentrations measured (25.6 μg m-3 outdoors, 23.4 μg m-3 indoors) are significantly higher than those reported in other studies, and characterised by higher carbonaceous and mineral matter contents and a lower proportion of secondary inorganic ions. Results suggest that quasi-UFPs in Barcelona are affected by local sources in the schools, mainly human activity (e.g. organic material from textiles, etc.; contributing 23-46% to total quasi-UFP mass) and playgrounds (in the form of mineral matter, contributing about 9% to the quasi-UFP mass). The particle size distribution of toxicologically relevant metals and major aerosol components was characterised, displaying bimodal size distributions for most elements and components, and a unimodal distribution for inorganic salts (ammonium nitrate and sulphate) and elemental carbon (EC). Regarding metals, Ni and Cr were partitioned mainly in quasi-UFPs and could thus be of interest for epidemiological studies, given their high redox properties. Children exposure to quasi-UFP mass and chemical species was assessed by comparing the concentrations measured at urban background and traffic areas schools. Finally, three main indoor sources across all size fractions were identified by assessing indoor/outdoor ratios (I/O) of PM species used as their tracers: human activity (organic material), cleaning products, paints and plastics (Cl- source), and a metallic mixed source (comprising combinations of Cu, Zn, Co, Cd, Pb, As, V and Cr).

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

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Tripathi, S. N.; Aggarwal, S. G.; Arola, A.

    2010-12-01

    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 model shapes, the SSA was found to vary depending on hematite

  4. Energetic Particle-induced Geodesic Acoustic Mode

    SciTech Connect

    Fu, G.Y.

    2008-09-12

    A new energetic particle-induced Geodesic Acoustic Mode (EGAM) is shown to exist. The mode frequency, mode structure, and mode destabilization are determined non-perturbatively by energetic particle kinetic effects. In particular the EGAM frequency is found to be substantially lower than the standard GAM frequency. The radial mode width is determined by the energetic particle drift orbit width and can be fairly large for high energetic particle pressure and large safety factor. These results are consistent with the recent experimental observation of the beam- driven n=0 mode in DIII-D. The new mode is important since it can degrade energetic particle confinement as shown in the DIII-D experiments. The new mode may also affect the thermal plasma confinement via its interaction with plasma micro-turbulence.

  5. Flow field induced particle accumulation inside droplets in rectangular channels.

    PubMed

    Hein, Michael; Moskopp, Michael; Seemann, Ralf

    2015-07-01

    Particle concentration is a basic operation needed to perform washing steps or to improve subsequent analysis in many (bio)-chemical assays. In this article we present field free, hydrodynamic accumulation of particles and cells in droplets flowing within rectangular micro-channels. Depending on droplet velocity, particles either accumulate at the rear of the droplet or are dispersed over the entire droplet cross-section. We show that the observed particle accumulation behavior can be understood by a coupling of particle sedimentation to the internal flow field of the droplet. The changing accumulation patterns are explained by a qualitative change of the internal flow field. The topological change of the internal flow field, however, is explained by the evolution of the droplet shape with increasing droplet velocity altering the friction with the channel walls. In addition, we demonstrate that accumulated particles can be concentrated, removing excess dispersed phase by splitting the droplet at a simple channel junction. PMID:26032835

  6. Germanium accumulation-mode charge-injection-device process

    NASA Technical Reports Server (NTRS)

    Moore, T. G.

    1981-01-01

    Gallium doped germanium is suitable for applications in the detection of far infrared radiation. Measurements were made on experimental photoconductors (PCs), accumulation mode charge injection devices (AMCIDs), and the SSPC (a switched, sampled PC alternative to the AMCID). The results indicate that the SSPC, which had a responsivity near 1.5 amp/watt, is desirable for use in two dimensional detector arrays.

  7. Energetic particle effects on global MHD modes

    SciTech Connect

    Cheng, C.Z.

    1990-01-01

    The effects of energetic particles on MHD type modes are studied by analytical theories and the nonvariational kinetic-MHD stability code (NOVA-K). In particular we address the problems of (1) the stabilization of ideal MHD internal kink modes and the excitation of resonant fishbone'' internal modes and (2) the alpha particle destabilization of toroidicity-induced Alfven eigenmodes (TAE) via transit resonances. Analytical theories are presented to help explain the NOVA-K results. For energetic trapped particles generated by neutral-beam injection (NBI) or ion cyclotron resonant heating (ICRH), a stability window for the n=1 internal kink mode in the hot particle beat space exists even in the absence of core ion finite Larmor radius effect (finite {omega}{sub *i}). On the other hand, the trapped alpha particles are found to resonantly excite instability of the n=1 internal mode and can lower the critical beta threshold. The circulating alpha particles can strongly destabilize TAE modes via inverse Landau damping associated with the spatial gradient of the alpha particle pressure. 23 refs., 5 figs.

  8. Forest canopy interactions with nucleation mode particles

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Hornsby, K. E.; Novick, K. A.

    2014-07-01

    Forests play a key role in removal of particles from the atmosphere but may also significantly contribute to formation and growth of ultrafine particles. Ultrafine particle size distributions through a deciduous forest canopy indicate substantial capture of nucleation mode particles by the foliage. Concentrations decline with depth into the canopy, such that nucleation mode number concentrations at the bottom of the canopy are an average of 16% lower than those at the top. However, growth rates of nucleation mode particles (diameters 6-30 nm) are invariant with height within the canopy, which implies that the semi-volatile gases contributing to their growth are comparatively well-mixed through the canopy. Growth rates of nucleation mode particles during a meteorological drought year (2012) were substantially lower than during a meteorologically normal year with high soil water potential (2013). This may reflect suppression of actual BVOC emissions by drought and thus reduced production of condensable products (and thus particle growth) during the drought-affected vegetation season. This hypothesis is supported by evidence that growth rates during the normal year exhibit a positive correlation with emissions of biogenic volatile organic compounds (BVOC) modeled based on observed forest composition, leaf area index, temperature and PAR, but particle growth rates during the drought-affected vegetation season are not correlated with modeled BVOC emissions. These data thus provide direct evidence for the importance of canopy capture in atmospheric particle budgets and indirect evidence that drought-stress in forests may reduce BVOC emissions and limit growth of nucleation mode particles to climate-relevant sizes.

  9. Particle Distribution Modification by Low Amplitude Modes

    SciTech Connect

    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.

  10. Geodesic Acoustic Modes Induced by Energetic Particles

    NASA Astrophysics Data System (ADS)

    Zhou, Tianchun; Berk, Herbert

    2009-11-01

    A global geodesic acoustic mode driven by energetic particles (EGAM) has been observed in JET[1, 2] and DIII D[3, 4]. The mode is to be treated fully kinetically. The descriptions of the background electrons and ions are based on standard high and low bounce frequency expansion respectively with respect to the mode frequency. However, the energetic ions must be treated without any expansion of ratio between their bounce frequency and the mode frequency since they are comparable. Under electrostatic perturbation, we construct a quadratic form for the wave amplitude, from which an integro-differential equation is derived. In the limit where the drift orbit width is small comparison with the mode width, a differential equation for perturbed electrostatic field is obtained. Solution is obtained both analytically and numerically. We find that beam counterinjection enhances the instability of the mode. Landau damping due to thermal species is investigated.

  11. Geodesic Acoustic Modes Induced by Energetic Particles

    NASA Astrophysics Data System (ADS)

    Zhou, Tianchun; Berk, Herbert

    2009-05-01

    A global geodesic acoustic mode driven by energetic particles (EGAM) has been observed in JET[1, 2] and DIII D[3, 4]. The mode is to be treated fully kinetically. The descriptions of the background electrons and ions are based on standard high and low bounce frequency expansion respectively with respect to the mode frequency. However, the energetic ions must be treated without any expansion of ratio between their bounce frequency and the mode frequency since they are comparable. Under electrostatic perturbation, we construct a quadratic form for the wave amplitude, from which an integro-differential equation is derived. In the limit where the drift orbit width is small comparison with the mode width, a differential equation for perturbed electrostatic field is obtained. Solution is obtained both analytically and numerically. We find that beam counterinjection enhances the instability of the mode

  12. Forest canopy interactions with nucleation mode particles

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Hornsby, K. E.; Novick, K. A.

    2014-11-01

    Ultrafine particle size distributions through a deciduous forest canopy indicate that nucleation mode particle concentrations decline with depth into the canopy, such that number concentrations at the bottom of the canopy are an average of 16% lower than those at the top. However, growth rates of nucleation mode particles (diameters 6-30 nm) are invariant with height within the canopy, which implies that the semi-volatile gases contributing to their growth are comparatively well-mixed through the canopy. Growth rates of nucleation mode particles during a meteorological drought year (2012) were substantially lower than during a meteorologically normal year with high soil water potential (2013). This may reflect suppression of actual biogenic volatile organic compound (BVOC) emissions by drought and thus a reduction in the production of condensable products during the drought-affected vegetation season. This hypothesis is supported by evidence that growth rates during the normal year exhibit a positive correlation with emissions of BVOC modeled on observed forest composition, leaf area index, temperature and photosynthetically active radiation (PAR), but particle growth rates during the drought-affected vegetation season are not correlated with modeled BVOC emissions. These data thus provide indirect evidence that drought stress in forests may reduce BVOC emissions and limit growth of nucleation mode particles to climate-relevant sizes.

  13. The organic fraction of bubble-generated, accumulation mode Sea Spray Aerosol (SSA)

    NASA Astrophysics Data System (ADS)

    Modini, R. L.; Harris, B.; Ristovski, Z. D.

    2010-03-01

    Recent studies have detected a dominant accumulation mode (~100 nm) in the Sea Spray Aerosol (SSA) number distribution. There is evidence to suggest that particles in this mode are composed primarily of organics. To investigate this hypothesis we conducted experiments on NaCl, artificial SSA and natural SSA particles with a Volatility-Hygroscopicity-Tandem-Differential-Mobility-Analyser (VH-TDMA). NaCl particles were atomiser generated and a bubble generator was constructed to produce artificial and natural SSA particles. Natural seawater samples for use in the bubble generator were collected from biologically active, terrestrially-affected coastal water in Moreton Bay, Australia. Differences in the VH-TDMA-measured volatility curves of artificial and natural SSA particles were used to investigate and quantify the organic fraction of natural SSA particles. Hygroscopic Growth Factor (HGF) data, also obtained by the VH-TDMA, were used to confirm the conclusions drawn from the volatility data. Both datasets indicated that the organic fraction of our natural SSA particles evaporated in the VH-TDMA over the temperature range 170-200 °C. The organic volume fraction for 71-77 nm natural SSA particles was 8±6%. Organic volume fraction did not vary significantly with varying water residence time (40 s to 24 h) in the bubble generator or SSA particle diameter in the range 38-173 nm. At room temperature we measured shape- and Kelvin-corrected HGF at 90% RH of 2.46±0.02 for NaCl, 2.35±0.02 for artifical SSA and 2.26±0.02 for natural SSA particles. Overall, these results suggest that the natural accumulation mode SSA particles produced in these experiments contained only a minor organic fraction, which had little effect on hygroscopic growth. Our measurement of 8±6% is an order of magnitude below two previous measurements of the organic fraction in SSA particles of comparable sizes. We stress that our results were obtained using coastal seawater and they can't necessarily

  14. The organic fraction of bubble-generated, accumulation mode Sea Spray Aerosol (SSA)

    NASA Astrophysics Data System (ADS)

    Modini, R. L.; Harris, B.; Ristovski, Z. D.

    2009-10-01

    Recent studies have detected a dominant accumulation mode (~100 nm) in the Sea Spray Aerosol (SSA) number distribution. There is evidence to suggest that particles in this mode are composed primarily of organics. To investigate this hypothesis we conducted experiments on NaCl, artificial SSA and natural SSA particles with a Volatility-Hygroscopicity-Tandem-Differential-Mobility-Analyser (VH-TDMA). NaCl particles were atomiser generated and a bubble generator was constructed to produce artificial and natural SSA particles. Natural seawater samples for use in the bubble generator were collected from biologically active, terrestrially-affected coastal water in Moreton Bay, Australia. Differences in the VH-TDMA-measured volatility curves of artificial and natural SSA particles were used to investigate and quantify the organic fraction of natural SSA particles. Hygroscopic Growth Factor (HGF) data, also obtained by the VH-TDMA, were used to confirm the conclusions drawn from the volatility data. Both datasets indicated that the organic fraction of our natural SSA particles evaporated in the VH-TDMA over the temperature range 170-200°C. The organic volume fraction for 71-77 nm natural SSA particles was 8±6%. Organic volume fraction did not vary significantly with varying water residence time (40 s0 to 24 h) in the bubble generator or SSA particle diameter in the range 38-173 nm. At room temperature we measured shape- and Kelvin-corrected HGF at 90% RH of 2.46±0.02 for NaCl, 2.35±0.02 for artifical SSA and 2.26±0.02 for natural SSA particles. Overall, these results suggest that the natural accumulation mode SSA particles produced in these experiments contained only a minor organic fraction, which had little effect on hygroscopic growth. Our measurement of 8±6% is an order of magnitude below two previous measurements of the organic fraction in SSA particles of comparable sizes. Further studies with a variety of different seawaters are required to better quantify how

  15. Surface charge accumulation of particles containing radionuclides in open air

    DOE PAGESBeta

    Kim, Yong-ha; Yiacoumi, Sotira; Tsouris, Costas

    2015-05-01

    Radioactivity can induce charge accumulation on radioactive particles. But, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. Moreover, a charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify themore » particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. Our study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes.« less

  16. Surface charge accumulation of particles containing radionuclides in open air

    SciTech Connect

    Kim, Yong-ha; Yiacoumi, Sotira; Tsouris, Costas

    2015-05-01

    Radioactivity can induce charge accumulation on radioactive particles. But, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. Moreover, a charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify the particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. Our study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes.

  17. Evolution of the alpha particle driven toroidicity induced Alfven mode

    SciTech Connect

    Wu, Y.; White, R.B.; Cheng, C.Z.

    1994-04-01

    The interaction of alpha particles with a toroidicity induced Alfven eigenmode is investigated self-consistently by using a kinetic dispersion relation. All important poloidal harmonics and their radial mode profiles are included. A Hamiltonian guiding center code is used to simulate the alpha particle motion. The simulations include particle orbit width, nonlinear particle dynamics and the effects of the modes on the particles. Modification of the particle distribution leading to mode saturation is observed. There is no significant alpha particle loss.

  18. Particle accumulation on periodic orbits by repeated free surface collisions

    NASA Astrophysics Data System (ADS)

    Hofmann, Ernst; Kuhlmann, Hendrik C.

    2011-07-01

    The motion of small particles suspended in cylindrical thermocapillary liquid bridges is investigated numerically in order to explain the experimentally observed particle accumulation structures (PAS) in steady two- and time-dependent three-dimensional flows. Particles moving in this flow are modeled as perfect tracers in the bulk, which can undergo collisions with the free surface. By way of free-surface collisions the particles are transferred among different streamlines which represents the particle trajectories in the bulk. The inter-streamline transfer-process near the free surface together with the passive transport through the bulk is used to construct an iterative map that can describe the accumulation process as an attraction to a stable fixed point which represents PAS. The flow topology of the underlying azimuthally traveling hydrothermal wave turns out to be of key importance for the existence of PAS. In a frame of reference exactly rotating with the hydrothermal wave the three-dimensional flow is steady and exhibits co-existing regular and chaotic streamlines. We find that particles are attracted to accumulation structures if a closed regular streamline exists in the rotating frame of reference which closely approaches the free surface locally. Depending on the closed streamline and the particle radius PAS can arise as a specific trajectory which winds about the closed regular streamline or as the surface of a particular stream tube containing the closed streamline.

  19. Test Particles, Test Modes and Drift Turbulence

    SciTech Connect

    Vlad, Madalina; Spineanu, Florin

    2008-10-15

    Strong electrostatic turbulence in magnetically confined plasmas is characterized by trapping or eddying of test particle trajectories produced by the ExB stochastic drift. Trapping is shown to produce non-standard statistics of trajectories: non-Gaussian distribution, memory effects and quasi-coherence. Two types of effects produced by trapping are analyzed. The first type concerns particle and energy transport and consists in very strong nonlinear modification of the diffusion coefficients. Anomalous diffusion regimes are obtained when the other components of the motion (particle collisions, plasma rotation, the motion along the confining magnetic field) do not destroy trajectory eddying. The second type of effects are evidenced by studying test modes on turbulent plasma. We show that trappyng provides the physical mechanism for the inverse cascade observed in drift turbulence.

  20. Boat detection using vector accumulation of particle motion

    NASA Astrophysics Data System (ADS)

    Zhang, Xuguang; Li, Na; Li, Youyi; Li, Xiaoli

    2014-11-01

    Recently, target detection in sea environment such as boat detection has become a popular research topic which is significant for marine vessels monitoring system. Many target detection methods have been widely applied to practical applications such as frame difference, traditional optical flow and background subtraction method. However, the existing target detection methods are not suitable to deal with the complex conditions of sea surface, such as irregular movement of the waves and illumination changes. In this paper, we developed an approach based on vector accumulation of particle motion mainly aiming at eliminating the effects of irregular movement of waves. Our proposed method applies vector accumulation of particle motion to optical flow field to obtain more accurate detection results under complex conditions. Firstly, the traditional optical flow method is used to acquire motion vector of every particle. Furthermore, the vectors of each flow point are abstracted to represent the recording of a fluid element in the flow over a certain period, succeeding is the accumulation of particle vectors. Finally, we calculate the mean of the vector accumulation to eliminate the effects of irregular movement of waves based on the video. Experimental results show the proposed method can gain better performance than traditional optical flow method.

  1. Origin of particle accumulation structures in liquid bridges: Particle-boundary-interactions versus inertia

    NASA Astrophysics Data System (ADS)

    Muldoon, Frank H.; Kuhlmann, Hendrik C.

    2016-07-01

    The formation of particle-accumulation structures in the flow in a cylindrical liquid bridge driven by the thermocapillary effect is studied with the aim of determining the physical mechanism which forms the structures. The flow is modeled using the incompressible Navier-Stokes and energy equations with the assumption of constant fluid properties except for surface tension, which is assumed to depend linearly on temperature. Different models for the motion of small non-interacting spherical particles at low concentration are employed, taking into account particle inertia due to density differences between fluid and particles and the restricted particle motion near the boundaries of the flow domain. Attention is focused on differences in formation time between particle-accumulation structures arising as a result of inertial effects only, particle-boundary-interaction effects only, and a combination of the two.

  2. Transient Simulation of Accumulating Particle Deposition in Pipe Flow

    NASA Astrophysics Data System (ADS)

    Hewett, James; Sellier, Mathieu

    2015-11-01

    Colloidal particles that deposit in pipe systems can lead to fouling which is an expensive problem in both the geothermal and oil & gas industries. We investigate the gradual accumulation of deposited colloids in pipe flow using numerical simulations. An Euler-Lagrangian approach is employed for modelling the fluid and particle phases. Particle transport to the pipe wall is modelled with Brownian motion and turbulent diffusion. A two-way coupling exists between the fouled material and the pipe flow; the local mass flux of depositing particles is affected by the surrounding fluid in the near-wall region. This coupling is modelled by changing the cells from fluid to solid as the deposited particles exceed each local cell volume. A similar method has been used to model fouling in engine exhaust systems (Paz et al., Heat Transfer Eng., 34(8-9):674-682, 2013). We compare our deposition velocities and deposition profiles with an experiment on silica scaling in turbulent pipe flow (Kokhanenko et al., 19th AFMC, 2014).

  3. Trapped particle destabilization of the internal kink mode

    SciTech Connect

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  5. USE OF AN INERT RADIOACTIVE PARTICLE FOR MEASURING PARTICLE ACCUMULATION BY FILTER-FEEDING BIVALVE MOLLUSCS

    EPA Science Inventory

    The use of an inert, radioactively labeled microsphere as a measure of particle accumulation (filtration activity) by Mulinia lateralis (Say) and Mytilus edulis L. was evaluated. Bottom sediment plus temperature and salinity of the water were varied to induce changes in filtratio...

  6. Alpha particle effects on the internal kink modes

    SciTech Connect

    Wu, Yanlin; Cheng, C.Z.

    1994-08-01

    The {alpha}-particle effects on the internal kink mode stability are studied. Finite Grad-Shafranov Shift, plasma {beta}, and plasma shape can significantly enhance the trapped particle drift reversal domain in pitch angle space and reduce average magnetic drift frequency. The drift reversal effect on the ideal kink mode is small, but the {beta}{sub {alpha}} threshold for the fishbone mode can be much lower than previously predicted. In addition, the ion diamagnetic drift has a stronger destabilizing effect.

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

    PubMed

    Maimaiti, Aili; Truong, Viet Giang; Sergides, Marios; Gusachenko, Ivan; Nic Chormaic, Síle

    2015-01-01

    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 the 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. 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. Speed enhancement of polystyrene particle propulsion was observed for the higher order modes compared to the fundamental mode for particles ranging from 1 μm to 5 μm in diameter. The optical propelling velocity of a single, 3 μm polystyrene particle was found to be 8 times faster under the higher order mode than the fundamental mode field for a waist power of 25 mW. Experimental data are supported by theoretical calculations. This work can be extended to trapping and manipulation of laser-cooled atoms with potential for quantum networks. PMID:25766925

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

    PubMed Central

    Maimaiti, Aili; Truong, Viet Giang; Sergides, Marios; Gusachenko, Ivan; Nic Chormaic, Síle

    2015-01-01

    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 the 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. 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. Speed enhancement of polystyrene particle propulsion was observed for the higher order modes compared to the fundamental mode for particles ranging from 1 μm to 5 μm in diameter. The optical propelling velocity of a single, 3 μm polystyrene particle was found to be 8 times faster under the higher order mode than the fundamental mode field for a waist power of 25 mW. Experimental data are supported by theoretical calculations. This work can be extended to trapping and manipulation of laser-cooled atoms with potential for quantum networks. PMID:25766925

  9. Quasilinear Model for Energetic Particles Interacting with TAE Modes

    NASA Astrophysics Data System (ADS)

    Ghantous, Katy; Gorelenkov, Nikolai; Berk, Herbert

    2010-11-01

    TAE instabilities are thought to be a major source of Energetic Particle transport which could set limits on operational scenarios, especially for burning plasmas, and causes damage to the first wall. The quasilinear model proposed by Berk et al.ootnotetextH. L. Berk et al, Nucl. Fusion, 35:1661, 1995. relies on diffusion mechanisms for particle dynamics to captures the evolution of the energetic particle distribution function and the associated mode amplitude. Using the bump-on-tail as a paradigm, we analyze the dynamics near the resonances for accurate diffusion coefficient representation. We verify the model to get the predicted single mode saturation levels and benchmark the case of multimode overlap against particle codes. Using the TAE mode structures computed by the ideal MHD code NOVA, we generalize this method to relax energetic particles' profiles in the full 3D phase space.

  10. Global particle-in-cell simulations of Alfvenic modes

    SciTech Connect

    Mishchenko, A.; Koenies, A.; Hatzky, R.

    2008-11-01

    Global linear gyro-kinetic particle-in-cell (PIC) simulations of electromagnetic modes in pinch and tokamak geometries are reported. The Toroidal Alfven Eigenmode and the Kinetic Ballooning Mode have been simulated. All plasma species have been treated kinetically (i.e. no hybrid fluid-kinetic or reduced-kinetic model has been applied). The main intention of the paper is to demonstrate that the global Alfven modes can be treated with the gyro-kinetic PIC method.

  11. Alpha-particle effects on ballooning flute modes in tokamaks

    SciTech Connect

    Andrushchenko, Z.N.; Bijko, A.Y.; Cheremnykh, O.K. )

    1990-11-01

    In this paper a more accurate dispersion equation for ideal ballooning flute modes in a plasma with alpha particles is obtained. It is shown that circulating and trapped alpha particles generate the eigenbranches of the mode oscillations with frequencies {omega} {approx lt} {omega}{sub *i}, where {omega}{sub *i}, is the ion drift frequency. The relevant growth rates and frequencies are found. It is ascertained that in the frequency range {omega}{sub *i} {lt} {omega} {lt} {bar {omega}{sub Db}}, where {bar {omega}{sub Db}} is the magnetic drift frequency average over a bounce period, trapped alpha particles may generate forced oscillations that influence the ideal ballooning flute mode stability boundary. It is shown that the stability may be improved for certain plasma parameters and trapped alpha-particle pressures.

  12. Multi-peak accumulation and coarse modes observed from AERONET retrieved aerosol volume size distribution in Beijing

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Li, Zhengqiang; Zhang, Yuhuan; Chen, Yu; Cuesta, Juan; Ma, Yan

    2016-01-01

    We present characteristic peaks of atmospheric columnar aerosol volume size distribution retrieved from the AErosol RObotic NETwork (AERONET) ground-based Sun-sky radiometer observation, and their correlations with aerosol optical properties and meteorological conditions in Beijing over 2013. The results show that the aerosol volume particle size distribution (VPSD) can be decomposed into up to four characteristic peaks, located in accumulation and coarse modes, respectively. The mean center radii of extra peaks in accumulation and coarse modes locate around 0.28 (±0.09) to 0.38 (±0.11) and 1.25 (±0.56) to 1.47 (±0.30) μm, respectively. The multi-peak size distributions are found in different aerosol loading conditions, with the mean aerosol optical depth (440 nm) of 0.58, 0.49, 1.18 and 1.04 for 2-, 3-I/II and 4-peak VPSD types, while the correspondingly mean relative humidity values are 58, 54, 72 and 67 %, respectively. The results also show the significant increase (from 0.25 to 0.40 μm) of the mean extra peak median radius in the accumulation mode for the 3-peak-II cases, which agrees with aerosol hygroscopic growth related to relative humidity and/or cloud or fog processing.

  13. Multi-peak accumulation and coarse modes observed from AERONET retrieved aerosol volume size distribution in Beijing

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Li, Zhengqiang; Zhang, Yuhuan; Chen, Yu; Cuesta, Juan; Ma, Yan

    2016-08-01

    We present characteristic peaks of atmospheric columnar aerosol volume size distribution retrieved from the AErosol RObotic NETwork (AERONET) ground-based Sun-sky radiometer observation, and their correlations with aerosol optical properties and meteorological conditions in Beijing over 2013. The results show that the aerosol volume particle size distribution (VPSD) can be decomposed into up to four characteristic peaks, located in accumulation and coarse modes, respectively. The mean center radii of extra peaks in accumulation and coarse modes locate around 0.28 (±0.09) to 0.38 (±0.11) and 1.25 (±0.56) to 1.47 (±0.30) μm, respectively. The multi-peak size distributions are found in different aerosol loading conditions, with the mean aerosol optical depth (440 nm) of 0.58, 0.49, 1.18 and 1.04 for 2-, 3-I/II and 4-peak VPSD types, while the correspondingly mean relative humidity values are 58, 54, 72 and 67 %, respectively. The results also show the significant increase (from 0.25 to 0.40 μm) of the mean extra peak median radius in the accumulation mode for the 3-peak-II cases, which agrees with aerosol hygroscopic growth related to relative humidity and/or cloud or fog processing.

  14. High frequency single mode traveling wave structure for particle acceleration

    NASA Astrophysics Data System (ADS)

    Ivanyan, M. I.; Danielyan, V. A.; Grigoryan, B. A.; Grigoryan, A. H.; Tsakanian, A. V.; Tsakanov, V. M.; Vardanyan, A. S.; Zakaryan, S. V.

    2016-09-01

    The development of the new high frequency slow traveling wave structures is one of the promising directions in accomplishment of charged particles high acceleration gradient. The disc and dielectric loaded structures are the most known structures with slowly propagating modes. In this paper a large aperture high frequency metallic two-layer accelerating structure is studied. The electrodynamical properties of the slowly propagating TM01 mode in a metallic tube with internally coated low conductive thin layer are examined.

  15. Conduction Threshold in Accumulation-Mode InGaZnO Thin Film Transistors

    PubMed Central

    Lee, Sungsik; Nathan, Arokia

    2016-01-01

    The onset of inversion in the metal-oxide-semiconductor field-effect transistor (MOSFET) takes place when the surface potential is approximately twice the bulk potential. In contrast, the conduction threshold in accumulation mode transistors, such as the oxide thin film transistor (TFT), has remained ambiguous in view of the complex density of states distribution in the mobility gap. This paper quantitatively describes the conduction threshold of accumulation-mode InGaZnO TFTs as the transition of the Fermi level from deep to tail states, which can be defined as the juxtaposition of linear and exponential dependencies of the accumulated carrier density on energy. Indeed, this permits direct extraction and visualization of the threshold voltage in terms of the second derivative of the drain current with respect to gate voltage. PMID:26932790

  16. Conduction Threshold in Accumulation-Mode InGaZnO Thin Film Transistors.

    PubMed

    Lee, Sungsik; Nathan, Arokia

    2016-01-01

    The onset of inversion in the metal-oxide-semiconductor field-effect transistor (MOSFET) takes place when the surface potential is approximately twice the bulk potential. In contrast, the conduction threshold in accumulation mode transistors, such as the oxide thin film transistor (TFT), has remained ambiguous in view of the complex density of states distribution in the mobility gap. This paper quantitatively describes the conduction threshold of accumulation-mode InGaZnO TFTs as the transition of the Fermi level from deep to tail states, which can be defined as the juxtaposition of linear and exponential dependencies of the accumulated carrier density on energy. Indeed, this permits direct extraction and visualization of the threshold voltage in terms of the second derivative of the drain current with respect to gate voltage. PMID:26932790

  17. Conduction Threshold in Accumulation-Mode InGaZnO Thin Film Transistors

    NASA Astrophysics Data System (ADS)

    Lee, Sungsik; Nathan, Arokia

    2016-03-01

    The onset of inversion in the metal-oxide-semiconductor field-effect transistor (MOSFET) takes place when the surface potential is approximately twice the bulk potential. In contrast, the conduction threshold in accumulation mode transistors, such as the oxide thin film transistor (TFT), has remained ambiguous in view of the complex density of states distribution in the mobility gap. This paper quantitatively describes the conduction threshold of accumulation-mode InGaZnO TFTs as the transition of the Fermi level from deep to tail states, which can be defined as the juxtaposition of linear and exponential dependencies of the accumulated carrier density on energy. Indeed, this permits direct extraction and visualization of the threshold voltage in terms of the second derivative of the drain current with respect to gate voltage.

  18. Sausage mode of a pinched charged particle beam

    SciTech Connect

    Lee, E.P.

    1981-02-10

    The axisymmetric oscillations of a self-pinched charged particle beam are analyzed using a dispersion relation derived from a 3/2 dimensional model. This calculation includes the effects of rounded profiles, finite conductivity, a steady return current, and phase mix damping among particle orbits. However, only the lowest order radial mode of distortion is treated, and this is done in an approximate fashion.

  19. Particle Trajectories and Agglomeration/Accumulation in Branching Arteries subjected to Orbital Atherectomy

    PubMed Central

    Helgeson, Zach L; Jenkins, Jed S; Abraham, John P; Sparrow, Ephraim M

    2011-01-01

    Background: The transport of particles in surrogate and actual arterial geometries has been investigated synergistically by experimentation and numerical simulation. The motivating application for this work is orbital atherectomy which spawns a particle cloud in the process of debulking plaque from arterial walls. Methods: Paired simulations and experiments were performed to prove the capability of the simulation model to predict both fluid and particle motions in branched arterial geometries. The verified model was then employed to predict the pattern of fluid flow in an actual multi-branched arterial geometry, including the flowrates passing through each of the individual branches. These predictions are in very good agreement with experimental data. Focus was then shifted to the issues of particle agglomeration within the flowing fluid and particle accumulation on the vessel walls. Once again, a synergistic approach was used. Flow visualization was employed to track the particle motions and to identify possible particle agglomeration within the fluid. Results and Conclusions: Accumulation of particles on walls was identified by measuring size distributions of effluent and residue within the artery. Scanning Electron Microscopy (SEM) evaluation showed evidence of a size-based sorting as the particles passed through vessels. It was found that plaque-facsimile particles resisted particle-particle agglomeration. They also did not accumulate to the wall of the facsimile artery. In addition, simulations showed that if particle-wall accumulation were to occur, it would be limited to very small regions in the artery branches. PMID:21643425

  20. The one charged particle decay modes of the tau

    SciTech Connect

    Perl, M.L.

    1987-11-01

    Tables of measurements of the total branching fraction of tau lepton decays to modes with one charged particle are given along with the major individual branching fractions. The reason a combination of measurements and calculations is needed to display the discrepancy is described briefly. It is argued that uncertainties in measurements of the branching fractions for multiple photon decay modes prevent complete reliance on experiment. The multiple photon modes are discussed in more detail. Present research on experimental technique problems relative to the apparent discrepancy is summarized. (LEW)

  1. Accumulation of heavy particles around a helical vortex filament

    NASA Astrophysics Data System (ADS)

    IJzermans, Rutger H. A.; Hagmeijer, Rob; van Langen, Pieter J.

    2007-10-01

    The motion of small heavy particles near a helical vortex filament in incompressible flow is investigated. Both the configurations of a helical vortex filament in free space and a helical vortex filament in a concentric pipe are considered, and the corresponding helically symmetric velocity fields are expressed in terms of a stream function. Particle motion is assumed to be driven by Stokes drag, and the flow fields are assumed to be independent from the motion of particles. Numerical results show that heavy particles may be attracted to helical trajectories. The stability of these attraction trajectories is demonstrated by linear stability analysis. In addition, the correlation between the attraction trajectories and the streamline topologies is investigated.

  2. Characterization of accumulation-mode Si/SiGe triple quantum dots

    NASA Astrophysics Data System (ADS)

    Hazard, T. M.; Zajac, D. M.; Mi, X.; Zhang, S. S.; Petta, J. R.

    The transition from quantum dots fabricated from doped Si/SiGe quantum wells to undoped accumulation-mode structures has greatly improved the performance of few-electron quantum dots. Our accumulation-mode devices are reconfigurable and allow for operation as single, double, or triple quantum dots. In these devices, we measure typical charging energies Ec = 5 . 7 meV, orbital excited state energies as large as Eo = 2.9 meV, and valley splittings of up to Ev = 80 μeV. With the device configured as a triple quantum dot, we easily reach the (1,1,1) charge configuration. The gate architecture allows the interdot tunnel coupling to be tuned over a wide range, which is important for operation as an exchange-only spin qubit. Research sponsored by ARO Grant No. W911NF-15-1-0149.

  3. Compact solid-state neutral particle analyzer in current mode.

    PubMed

    Zhu, Y B; Bortolon, A; Heidbrink, W W; Celle, S L; Roquemore, A L

    2012-10-01

    Solid state neutral particle analyzer (ssNPA) arrays are operated in current mode on the DIII-D tokamak and the National Spherical Torus Experiment (NSTX). Compared with conventional pulse-counting NPAs, current-mode operation sacrifices energy resolution to obtain economical, high-bandwidth, pitch-angle resolved measurements. With the success from a new three-channel near-vertical-view current mode ssNPA on DIII-D, the apertures on an existing array on NSTX were expanded to increase the particle influx. The sightlines of both arrays intersect heating beams, enabling both active and passive charge exchange measurements. The spatial resolution at beam intersection is typically 5 cm on both devices. Directly deposited ultra-thin foils on the detector surface block stray photons below the energy of 1 keV and also set low energy threshold about 25 keV for deuterium particle detection. Oscillations in neutral flux produced by high frequency magnetohydrodynamics (MHD) instabilities are readily detected. PMID:23126831

  4. IMPACT OF PARTICLE AGGLOMERATION ON ACCUMULATION RATES IN THE GLASS DISCHARGE RISER OF HLW MELTER

    SciTech Connect

    Matyas, Josef; Jansik, Danielle P.; Owen, Antionette T.; Rodriguez, Carmen P.; Lang, Jesse B.; Kruger, Albert A.

    2013-08-05

    The major factor limiting waste loading in continuous high-level radioactive waste (HLW) melters is an accumulation of particles in the glass discharge riser during a frequent and periodic idling of more than 20 days. An excessive accumulation can produce robust layers a few centimeters thick, which may clog the riser, preventing molten glass from being poured into canisters. Since the accumulation rate is driven by the size of particles we investigated with X-ray microtomography, scanning electron microscopy, and image analysis the impact of spinel forming components, noble metals, and alumina on the size, concentration, and spatial distribution of particles, and on the accumulation rate. Increased concentrations of Fe and Ni in the baseline glass resulted in the formation of large agglomerates that grew over the time to an average size of ~185±155 µm, and produced >3 mm thick layer after 120 h at 850 °C. The noble metals decreased the particle size, and therefore significantly slowed down the accumulation rate. Addition of alumina resulted in the formation of a network of spinel dendrites which prevented accumulation of particles into compact layers.

  5. Impact Of Particle Agglomeration On Accumulation Rates In The Glass Discharge Riser Of HLW Melter

    SciTech Connect

    Kruger, A. A.; Rodriguez, C. A.; Matyas, J.; Owen, A. T.; Jansik, D. P.; Lang, J. B.

    2012-11-12

    The major factor limiting waste loading in continuous high-level radioactive waste (HLW) melters is an accumulation of particles in the glass discharge riser during a frequent and periodic idling of more than 20 days. An excessive accumulation can produce robust layers a few centimeters thick, which may clog the riser, preventing molten glass from being poured into canisters. Since the accumulation rate is driven by the size of particles we investigated with x-ray microtomography, scanning electron microscopy, and image analysis the impact of spinel forming components, noble metals, and alumina on the size, concentration, and spatial distribution of particles, and on the accumulation rate. Increased concentrations of Fe and Ni in the baseline glass resulted in the formation of large agglomerates that grew over the time to an average size of ~185+-155 {mu}m, and produced >3 mm thick layer after 120 h at 850 deg C. The noble metals decreased the particle size, and therefore significantly slowed down the accumulation rate. Addition of alumina resulted in the formation of a network of spinel dendrites which prevented accumulation of particles into compact layers.

  6. Sediment particle size and initial radiocesium accumulation in ponds following the Fukushima DNPP accident

    PubMed Central

    Yoshimura, Kazuya; Onda, Yuichi; Fukushima, Takehiko

    2014-01-01

    This study used particle size analysis to investigate the initial accumulation and trap efficiency of radiocesium (137Cs) in four irrigation ponds, ~4–5 months after the Fukushima Dai–ichi nuclear power plant (DNPP) accident. Trap efficiency, represented by the inventory of 137Cs in pond sediment to the inventory of radiocesium in soil surrounding the pond (i.e., total 137Cs inventory), was less than 100% for all but one pond. Trap efficiency decreased as sediment particle size increased, indicating that sediments with a smaller particle size accumulate more 137Cs. In ponds showing low trap efficiency, fine sediment containing high concentrations of 137Cs appeared to be removed from the system by hydraulic flushing, leaving behind mostly coarse sediment. The results of this study suggest that sediment particle size can be used to estimate the initial accumulation and trap efficiency of 137Cs in pond sediment, as well as the amount lost through hydraulic flushing. PMID:24682011

  7. Particle simulations of mode conversion between slow mode and fast mode in lower hybrid range of frequencies

    NASA Astrophysics Data System (ADS)

    Jia, Guozhang; Xiang, Nong; Wang, Xueyi; Huang, Yueheng; Lin, Yu

    2016-01-01

    The propagation and mode conversion of lower hybrid waves in an inhomogeneous plasma are investigated by using the nonlinear δf algorithm in a two-dimensional particle-in-cell simulation code based on the gyrokinetic electron and fully kinetic ion (GeFi) scheme [Lin et al., Plasma Phys. Controlled Fusion 47, 657 (2005)]. The characteristics of the simulated waves, such as wavelength, frequency, phase, and group velocities, agree well with the linear theoretical analysis. It is shown that a significant reflection component emerges in the conversion process between the slow mode and the fast mode when the scale length of the density variation is comparable to the local wavelength. The dependences of the reflection coefficient on the scale length of the density variation are compared with the results based on the linear full wave model for cold plasmas. It is indicated that the mode conversion for the waves with a frequency of 2.45 GHz (ω ˜ 3ωLH, where ωLH represents the lower hybrid resonance) and within Tokamak relevant amplitudes can be well described in the linear scheme. As the frequency decreases, the modification due to the nonlinear term becomes important. For the low-frequency waves (ω ˜ 1.3ωLH), the generations of the high harmonic modes and sidebands through nonlinear mode-mode coupling provide new power channels and thus could reduce the reflection significantly.

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

    SciTech Connect

    Huang, J.; Tang, C. J.; Chen, S. Y.; Wang, Z. H.

    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.

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

    NASA Astrophysics Data System (ADS)

    Huang, J.; Chen, S. Y.; Wang, Z. H.; Tang, C. J.

    2015-12-01

    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.

  10. Excitation of external kink mode by trapped energetic particles

    NASA Astrophysics Data System (ADS)

    Guo, S. C.; Xu, X. Y.; Liu, Y. Q.; Wang, Z. R.

    2016-05-01

    An unstable fishbone-like non-resonant external kink mode (FLEM) is numerically found to be driven by the precessional drift motion of trapped energetic particles (EPs) in both reversed-field pinch (RFP) and tokamak plasmas, even under the ideal wall boundary condition. In the presence of a sufficiently large fraction of trapped energetic ions in high beta plasmas, the FLEM instability may occur. The excitation condition is discussed in detail. The frequency of the FLEM is linked to the precessional drift frequency of EPs, and varies with the plasma flow speed. Therefore, it is usually much higher than that of the typical resistive wall mode (RWM). In general, the growth rate of FLEM does not depend on the wall resistivity. However, the wall position can significantly affect the mode’s property. The drift kinetic effects from thermal particles (mainly due to the transit resonance of passing particles) play a stabilizing role on FLEMs. In the presence of EPs, the FLEM and the RWM can co-exist or even couple to each other, depending on the plasma parameters. The FLEM instabilities in RFP and tokamaks have rather similar physics nature, although certain sub-dominant characters appear differently in the two configurations.

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

    SciTech Connect

    Parsa, Z.

    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.

  12. Fast excitation of geodesic acoustic mode by energetic particle beams

    SciTech Connect

    Cao, Jintao; Qiu, Zhiyong; Zonca, Fulvio

    2015-12-15

    A new mechanism for geodesic acoustic mode (GAM) excitation by a not fully slowed down energetic particle (EP) beam is analyzed to explain experimental observations in Large Helical Device. It is shown that the positive velocity space gradient near the lower-energy end of the EP distribution function can strongly drive the GAM unstable. The new features of this EP-induced GAM (EGAM) are: (1) no instability threshold in the pitch angle; (2) the EGAM frequency can be higher than the local GAM frequency; and (3) the instability growth rate is much larger than that driven by a fully slowed down EP beam.

  13. Density dependence of electron mobility in the accumulation mode for fully depleted SOI films

    SciTech Connect

    Naumova, O. V. Zaitseva, E. G.; Fomin, B. I.; Ilnitsky, M. A.; Popov, V. P.

    2015-10-15

    The electron mobility µ{sub eff} in the accumulation mode is investigated for undepleted and fully depleted double-gate n{sup +}–n–n{sup +} silicon-on-insulator (SOI) metal–oxide–semiconductor field-effect transistors (MOSFET). To determine the range of possible values of the mobility and the dominant scattering mechanisms in thin-film structures, it is proposed that the field dependence of the mobility µ{sub eff} be replaced with the dependence on the density N{sub e} of induced charge carriers. It is shown that the dependences µ{sub eff}(N{sub e}) can be approximated by the power functions µ{sub eff}(N{sub e}) ∝ N{sub e}{sup -n}, where the exponent n is determined by the chargecarrier scattering mechanism as in the mobility field dependence. The values of the exponent n in the dependences µ{sub eff}(N{sub e}) are determined when the SOI-film mode near one of its surfaces varies from inversion to accumulation. The obtained results are explained from the viewpoint of the electron-density redistribution over the SOI-film thickness and changes in the scattering mechanisms.

  14. Positron accumulation effect in particles embedded in a low-density matrix

    SciTech Connect

    Dryzek, Jerzy; Siemek, Krzysztof

    2015-02-07

    Systematic studies of the so-called positron accumulation effect for samples with particles embedded in a matrix are reported. This effect is related to energetic positrons which penetrate inhomogeneous medium. Due to differences in the linear absorption coefficient, different amounts of positrons are accumulated and annihilate in the identical volume of both materials. Positron lifetime spectroscopy and Doppler broadening of the annihilation line using Na-22 positrons were applied to the studies of the epoxy resin samples with embedded micro-sized particles of transition metals, i.e., Ni, Sn, Mo, W, and nonmetal particles, i.e., Si and NaF. The significant difference between the determined fraction of positrons annihilating in the particles and the particle volume fraction indicates the positron accumulation effect. The simple phenomenological model and Monte Carlo simulations are able to describe the main features of the obtained dependencies. The aluminum alloy with embedded Sn nanoparticles is also considered for demonstration differences between the accumulation and another related effect, i.e., the positron affinity.

  15. Rapid scene categorization: role of spatial frequency order, accumulation mode and luminance contrast.

    PubMed

    Kauffmann, Louise; Chauvin, Alan; Guyader, Nathalie; Peyrin, Carole

    2015-02-01

    Visual analysis follows a default, predominantly coarse-to-fine processing sequence. Low spatial frequencies (LSF) are processed more rapidly than high spatial frequencies (HSF), allowing an initial coarse parsing of visual input, prior to analysis of finer information. Our study investigated the influence of spatial frequency processing order, accumulation mode (i.e. how spatial frequency information is received as an input by the visual system, throughout processing), and differences in luminance contrast between spatial frequencies on rapid scene categorization. In Experiment 1, we used sequences composed of six filtered scenes, assembled from LSF to HSF (coarse-to-fine) or from HSF to LSF (fine-to-coarse) to test the effects of spatial frequency order. Spatial frequencies were either successive or additive within sequences to test the effects of spatial frequency accumulation mode. Results showed that participants categorized coarse-to-fine sequences more rapidly than fine-to-coarse sequences, irrespective of spatial frequency accumulation in the sequences. In Experiment 2, we investigated the extent to which differences in luminance contrast rather than in spatial frequency account for the advantage of coarse-to-fine over fine-to-coarse processing. Results showed that both spatial frequencies and luminance contrast account for a predominant coarse-to-fine processing, but that the coarse-to-fine advantage stems mainly from differences in spatial frequencies. Our study cautions against the use of contrast normalization in studies investigating spatial frequency processing. We argue that this type of experimental manipulation can impair the intrinsic properties of a visual stimulus. As the visual system relies on these to enable recognition, bias may be induced in strategies of visual analysis. PMID:25499838

  16. On the near-wall accumulation of injectable particles in the microcirculation: smaller is not better

    NASA Astrophysics Data System (ADS)

    Lee, Tae-Rin; Choi, Myunghwan; Kopacz, Adrian M.; Yun, Seok-Hyun; Liu, Wing Kam; Decuzzi, Paolo

    2013-06-01

    Although most nanofabrication techniques can control nano/micro particle (NMP) size over a wide range, the majority of NMPs for biomedical applications exhibits a diameter of ~100 nm. Here, the vascular distribution of spherical particles, from 10 to 1,000 nm in diameter, is studied using intravital microscopy and computational modeling. Small NMPs (<=100 nm) are observed to move with Red Blood Cells (RBCs), presenting an uniform radial distribution and limited near-wall accumulation. Larger NMPs tend to preferentially accumulate next to the vessel walls, in a size-dependent manner (~70% for 1,000 nm NMPs). RBC-NMP geometrical interference only is responsible for this behavior. In a capillary flow, the effective radial dispersion coefficient of 1,000 nm particles is ~3-fold larger than Brownian diffusion. This suggests that sub-micron particles could deposit within diseased vascular districts more efficiently than conventional nanoparticles.

  17. New modes of particle acceleration, techniques & sources symposium. Summary report

    SciTech Connect

    Parsa, Z.

    1996-12-31

    A Symposium on {open_quotes}New Modes of Particle Acceleration Technique and Sources{close_quotes} was held August 19-23, 1996 at the Institute for Theoretical Physics (ITP) in Santa Barbara. This was the first of the 3 symposia hosted by the ITP and supported by its sponsor the National Science Foundation, as part of our {open_quotes}New Ideas for Particle Accelerators{close_quotes} program. The symposia was organized and chaired by Dr. Zohreh Parsa of ITP/Brookhaven National Laboratory. This Symposium provided a perspective on the future direction of the Advanced Accelerator Research. The experimental study of elementary particles has become concentrated at a few large laboratories throughout the world because of the size and cost of the accelerator facilities needed for this work. For example, the Large Hadron Collider (LHC) at CERN, currently under construction, is 27 km in circumference and is being financed by the European membership of CERN plus contributions from non-member nations. An evolutionary approach to construction of ever higher energy colliders will only continue this trend towards high cost and large size.

  18. The patterning behaviour and accumulation of spherical particles in a vibrated non-isothermal liquid

    NASA Astrophysics Data System (ADS)

    Lappa, Marcello

    2014-09-01

    A completely new phenomenon of particle accumulation in vibrated non-isothermal monodisperse suspensions of solid spheres (in a liquid) is analyzed. For the first time evidence is provided for this case that even in situations in which particle-particle hydrodynamic interactions are negligible (dilute systems), intriguing nonlinear effects can lead to the irreversible formation of well-defined particulate structures over "long" temporal scales, i.e., times much larger than the period of the applied vibrations. The long-range translational ordering is produced by the delicate interplay between convective effects (of thermovibrational nature) and the (inertial) response of each isolated particle to the time-periodic acceleration. A new family of particle attractors in the physical space is identified with the topological dimension being essentially a function of the "symmetry properties" of the considered vibrated system and related geometrical constraints.

  19. Improving Calculation Accuracies of Accumulation-Mode Fractions Based on Spectral of Aerosol Optical Depths

    NASA Astrophysics Data System (ADS)

    Ying, Zhang; Zhengqiang, Li; Yan, Wang

    2014-03-01

    Anthropogenic aerosols are released into the atmosphere, which cause scattering and absorption of incoming solar radiation, thus exerting a direct radiative forcing on the climate system. Anthropogenic Aerosol Optical Depth (AOD) calculations are important in the research of climate changes. Accumulation-Mode Fractions (AMFs) as an anthropogenic aerosol parameter, which are the fractions of AODs between the particulates with diameters smaller than 1μm and total particulates, could be calculated by AOD spectral deconvolution algorithm, and then the anthropogenic AODs are obtained using AMFs. In this study, we present a parameterization method coupled with an AOD spectral deconvolution algorithm to calculate AMFs in Beijing over 2011. All of data are derived from AErosol RObotic NETwork (AERONET) website. The parameterization method is used to improve the accuracies of AMFs compared with constant truncation radius method. We find a good correlation using parameterization method with the square relation coefficient of 0.96, and mean deviation of AMFs is 0.028. The parameterization method could also effectively solve AMF underestimate in winter. It is suggested that the variations of Angstrom indexes in coarse mode have significant impacts on AMF inversions.

  20. Accumulation of lipids and oxidatively damaged DNA in hepatocytes exposed to particles

    SciTech Connect

    Vesterdal, Lise K.; Danielsen, Pernille H.; Folkmann, Janne K.; Jespersen, Line F.; Aguilar-Pelaez, Karin; Roursgaard, Martin; Loft, Steffen; Møller, Peter

    2014-01-15

    Exposure to particles has been suggested to generate hepatosteatosis by oxidative stress mechanisms. We investigated lipid accumulation in cultured human hepatocytes (HepG2) and rat liver after exposure to four different carbon-based particles. HepG2 cells were exposed to particles for 3 h and subsequently incubated for another 18 h to manifest lipid accumulation. In an animal model of metabolic syndrome we investigated the association between intake of carbon black (CB, 14 nm) particles and hepatic lipid accumulation, inflammation and gene expression of Srebp-1, Fasn and Scd-1 involved in lipid synthesis. There was a concentration-dependent increase in intracellular lipid content after exposure to CB in HepG2 cells, which was only observed after co-exposure to oleic/palmitic acid. Similar results were observed in HepG2 cells after exposure to diesel exhaust particles, fullerenes C{sub 60} or pristine single-walled carbon nanotubes. All four types of particles also generated oxidatively damaged DNA, assessed as formamidopyrimidine DNA glycosylase (FPG) sensitive sites, in HepG2 cells after 3 h exposure. The animal model of metabolic syndrome showed increased lipid load in the liver after one oral exposure to 6.4 mg/kg of CB in lean Zucker rats. This was not associated with increased iNOS staining in the liver, indicating that the oral CB exposure was associated with hepatic steatosis rather than steatohepatitis. The lipid accumulation did not seem to be related to increased lipogenesis because there were unaltered gene expression levels in both the HepG2 cells and rat livers. Collectively, exposure to particles is associated with oxidative stress and steatosis in hepatocytes. - Highlights: • Oral exposure to nanosized carbon black was associated with hepatosteatosis in rats. • In vitro studies included carbon black, C{sub 60}, diesel exhaust particles and SWCNTs. • Exposure to particles and free fatty acids increased lipid load in HepG2 cells. • Unaltered

  1. Modified Lipoprotein-Derived Lipid Particles Accumulate in Human Stenotic Aortic Valves

    PubMed Central

    Lehti, Satu; Käkelä, Reijo; Hörkkö, Sohvi; Kummu, Outi; Helske-Suihko, Satu; Kupari, Markku; Werkkala, Kalervo; Kovanen, Petri T.; Öörni, Katariina

    2013-01-01

    In aortic stenosis plasma lipoprotein-derived lipids accumulate in aortic valves. Here, we first compared the lipid compositions of stenotic aortic valves and atherosclerotic plaque cores. Both pathological tissues were found to be enriched in cholesteryl linoleate, a marker of extracellularly accumulated lipoproteins. In addition, a large proportion of the phospholipids were found to contain arachidonic acid, the common precursor of a number of proinflammatory lipid mediators. Next, we isolated and characterized extracellular lipid particles from human stenotic and non-stenotic control valves, and compared them to plasma lipoproteins from the same subjects. The extracellular valvular lipid particles were isolated from 15 stenotic and 14 non-stenotic aortic valves. Significantly more apoB-100-containing lipid particles were found in the stenotic than in the non-stenotic valves. The majority of the lipid particles isolated from the non-stenotic valves had sizes (23±6.2 nm in diameter) similar to those of plasma low density lipoprotein (LDL) (22±1.5 nm), while the lipid particles from stenotic valves were not of uniform size, their sizes ranging from 18 to more than 500 nm. The lipid particles showed signs of oxidative modifications, and when compared to isolated plasma LDL particles, the lipid particles isolated from the stenotic valves had a higher sphingomyelin/phosphatidylcholine –ratio, and also higher contents of lysophosphatidylcholine and unesterified cholesterol. The findings of the present study reveal, for the first time, that in stenotic human aortic valves, infiltrated plasma lipoproteins have undergone oxidative and lipolytic modifications, and become fused and aggregated. The generated large lipid particles may contribute to the pathogenesis of human aortic stenosis. PMID:23762432

  2. Effect of typhoon on atmospheric aerosol particle pollutants accumulation over Xiamen, China.

    PubMed

    Yan, Jinpei; Chen, Liqi; Lin, Qi; Zhao, Shuhui; Zhang, Miming

    2016-09-01

    Great influence of typhoon on air quality has been confirmed, however, rare data especially high time resolved aerosol particle data could be used to establish the behavior of typhoon on air pollution. A single particle aerosol spectrometer (SPAMS) was employed to characterize the particles with particle number count in high time resolution for two typhoons of Soulik (2013) and Soudelor (2015) with similar tracks. Three periods with five events were classified during the whole observation time, including pre - typhoon (event 1 and event 2), typhoon (event 3 and event 4) and post - typhoon (event 5) based on the meteorological parameters and particle pollutant properties. First pollutant group appeared during pre-typhoon (event 2) with high relative contributions of V - Ni rich particles. Pollution from the ship emissions and accumulated by local processes with stagnant meteorological atmosphere dominated the formation of the pollutant group before typhoon. The second pollutant group was present during typhoon (event 3), while typhoon began to change the local wind direction and increase wind speed. Particle number count reached up to the maximum value. High relative contributions of V - Ni rich and dust particles with low value of NO3(-)/SO4(2-) was observed during this period, indicating that the pollutant group was governed by the combined effect of local pollutant emissions and long-term transports. The analysis of this study sheds a deep insight into understand the relationship between the air pollution and typhoon. PMID:27295441

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

    NASA Astrophysics Data System (ADS)

    Park, Jaehong; Workman, Jared; Blackman, Eric; Ren, Chuang; Siller, Robert

    2012-10-01

    Low Mach number, high plasma beta, fast mode shocks likely occur in the outflows from reconnection sites associated with solar flares. These shocks are sites of particle energization with observable consequences, but there has been much less work on understanding the underlying physics compared to that of Mach number shocks. To make progress, we have simulated a low Mach number/high beta shock using 2D particle-in-cell simulations with a ``moving wall'' method and studied the shock structure and particle acceleration processes therein [Park et. al (2012), Phys. Plasmas, 19, 062904]. The moving wall method can control the shock speed in the simulation frame to allow smaller simulation boxes and longer simulation times. We found that the modified two-stream instability in the shock transition region is responsible for shock sustenance via turbulent dissipation and entropy creation throughout the downstream region long after the initial shock formation. Particle tracking and the particle energy distributions show that both electrons and ions participate in shock-drift-acceleration (SDA). The simulation combined with a theoretical analysis reveals a two-temperature Maxwellian distribution for the electron energy distribution via SDA.

  4. Accumulation of Cu and Zn in discarded antifouling paint particles by the marine gastropod, Littorina littorea

    NASA Astrophysics Data System (ADS)

    Gammon, Melanie; Turner, Andrew; Brown, Murray T.

    2009-10-01

    The short-term (5 day) accumulation of Cu and Zn in different tissues of the marine gastropod, Littorina littorea, has been studied in the presence of ˜10 mg l -1 of antifouling paint particles and pre- or simultaneously contaminated algal food ( Ulva lactuca). Accumulation of Cu was observed in the head-foot, digestive gland-gonad complex and gills to extents dependent on how and when food was contaminated and administered. However, retention of Zn was only observed in the gills and only when L. littorea and U. lactuca were simultaneously exposed to paint particles. Relative to the alga, faecal material was highly enriched in Zn, suggesting that the animal is able to rapidly eliminate this metal, most likely through the formation and egestion of insoluble phosphate granules. Thus, L. littorea is a useful biomonitor of marine contamination by antifouling applications in respect of Cu but not Zn.

  5. Synchronization of particle motion induced by mode coupling in a two-dimensional plasma crystal.

    PubMed

    Couëdel, L; Zhdanov, S; Nosenko, V; Ivlev, A V; Thomas, H M; Morfill, G E

    2014-05-01

    The kinematics of dust particles during the early stage of mode-coupling induced melting of a two-dimensional plasma crystal is explored. It is found that the formation of the hybrid mode causes the particle vibrations to partially synchronize at the hybrid frequency. Phase- and frequency-locked hybrid particle motion in both vertical and horizontal directions (hybrid mode) is observed. The system self-organizes in a rhythmic pattern of alternating in-phase and antiphase oscillating chains of particles. The spatial orientation of the synchronization pattern correlates well with the directions of the maximal increment of the shear-free hybrid mode. PMID:25353905

  6. Temporal assessment of nanoparticle accumulation after experimental brain injury: Effect of particle size

    PubMed Central

    Bharadwaj, Vimala N.; Lifshitz, Jonathan; Adelson, P. David; Kodibagkar, Vikram D.; Stabenfeldt, Sarah E.

    2016-01-01

    Nanoparticle (NP) based therapeutic and theranostic agents have been developed for various diseases, yet application to neural disease/injury is restricted by the blood-brain-barrier (BBB). Traumatic brain injury (TBI) results in a host of pathological alterations, including transient breakdown of the BBB, thus opening a window for NP delivery to the injured brain tissue. This study focused on investigating the spatiotemporal accumulation of different sized NPs after TBI. Specifically, animal cohorts sustaining a controlled cortical impact injury received an intravenous injection of PEGylated NP cocktail (20, 40, 100, and 500 nm, each with a unique fluorophore) immediately (0 h), 2 h, 5 h, 12 h, or 23 h after injury. NPs were allowed to circulate for 1 h before perfusion and brain harvest. Confocal microscopy demonstrated peak NP accumulation within the injury penumbra 1 h post-injury. An inverse relationship was found between NP size and their continued accumulation within the penumbra. NP accumulation preferentially occurred in the primary motor and somatosensory areas of the injury penumbra as compared to the parietal association and visual area. Thus, we characterized the accumulation of particles up to 500 nm at different times acutely after injury, indicating the potential of NP-based TBI theranostics in the acute period after injury. PMID:27444615

  7. Temporal assessment of nanoparticle accumulation after experimental brain injury: Effect of particle size.

    PubMed

    Bharadwaj, Vimala N; Lifshitz, Jonathan; Adelson, P David; Kodibagkar, Vikram D; Stabenfeldt, Sarah E

    2016-01-01

    Nanoparticle (NP) based therapeutic and theranostic agents have been developed for various diseases, yet application to neural disease/injury is restricted by the blood-brain-barrier (BBB). Traumatic brain injury (TBI) results in a host of pathological alterations, including transient breakdown of the BBB, thus opening a window for NP delivery to the injured brain tissue. This study focused on investigating the spatiotemporal accumulation of different sized NPs after TBI. Specifically, animal cohorts sustaining a controlled cortical impact injury received an intravenous injection of PEGylated NP cocktail (20, 40, 100, and 500 nm, each with a unique fluorophore) immediately (0 h), 2 h, 5 h, 12 h, or 23 h after injury. NPs were allowed to circulate for 1 h before perfusion and brain harvest. Confocal microscopy demonstrated peak NP accumulation within the injury penumbra 1 h post-injury. An inverse relationship was found between NP size and their continued accumulation within the penumbra. NP accumulation preferentially occurred in the primary motor and somatosensory areas of the injury penumbra as compared to the parietal association and visual area. Thus, we characterized the accumulation of particles up to 500 nm at different times acutely after injury, indicating the potential of NP-based TBI theranostics in the acute period after injury. PMID:27444615

  8. Dual Mode NOx Sensor: Measuring Both the Accumulated Amount and Instantaneous Level at Low Concentrations

    PubMed Central

    Groß, Andrea; Beulertz, Gregor; Marr, Isabella; Kubinski, David J.; Visser, Jaco H.; Moos, Ralf

    2012-01-01

    The accumulating-type (or integrating-type) NOx sensor principle offers two operation modes to measure low levels of NOx: The direct signal gives the total amount dosed over a time interval and its derivative the instantaneous concentration. With a linear sensor response, no baseline drift, and both response times and recovery times in the range of the gas exchange time of the test bench (5 to 7 s), the integrating sensor is well suited to reliably detect low levels of NOx. Experimental results are presented demonstrating the sensor’s integrating properties for the total amount detection and its sensitivity to both NO and to NO2. We also show the correlation between the derivative of the sensor signal and the known gas concentration. The long-term detection of NOx in the sub-ppm range (e.g., for air quality measurements) is discussed. Additionally, a self-adaption of the measurement range taking advantage of the temperature dependency of the sensitivity is addressed. PMID:22736980

  9. Hybrid architecture for shallow accumulation mode AlGaAs/GaAs heterostructures with epitaxial gates

    SciTech Connect

    MacLeod, S. J.; See, A. M.; Hamilton, A. R.; Farrer, I.; Ritchie, D. A.; Ritzmann, J.; Ludwig, A.; Wieck, A. D.

    2015-01-05

    Accumulation mode devices with epitaxially grown gates have excellent electrical stability due to the absence of dopant impurities and surface states. We overcome typical fabrication issues associated with epitaxially gated structures (e.g., gate leakage and high contact resistance) by using separate gates to control the electron densities in the Ohmic and Hall bar regions. This hybrid gate architecture opens up a way to make ultrastable nanoscale devices where the separation between the surface gates and the 2D electron gas is small. In this work, we demonstrate that the hybrid devices made from the same wafer have reproducible electrical characteristics, with identical mobility and density traces over a large range of 2D densities. In addition, thermal cycling does not influence the measured electrical characteristics. As a demonstration of concept, we have fabricated a hybrid single-electron transistor on a shallow (50 nm) AlGaAs/GaAs heterostructure that shows clear Coulomb blockade oscillations in the low temperature conductance.

  10. On the near-wall accumulation of injectable particles in the microcirculation: smaller is not better

    PubMed Central

    Lee, Tae-Rin; Choi, Myunghwan; Kopacz, Adrian M.; Yun, Seok-Hyun; Liu, Wing Kam; Decuzzi, Paolo

    2013-01-01

    Although most nanofabrication techniques can control nano/micro particle (NMP) size over a wide range, the majority of NMPs for biomedical applications exhibits a diameter of ~100 nm. Here, the vascular distribution of spherical particles, from 10 to 1,000 nm in diameter, is studied using intravital microscopy and computational modeling. Small NMPs (≤100 nm) are observed to move with Red Blood Cells (RBCs), presenting an uniform radial distribution and limited near-wall accumulation. Larger NMPs tend to preferentially accumulate next to the vessel walls, in a size-dependent manner (~70% for 1,000 nm NMPs). RBC-NMP geometrical interference only is responsible for this behavior. In a capillary flow, the effective radial dispersion coefficient of 1,000 nm particles is ~3-fold larger than Brownian diffusion. This suggests that sub-micron particles could deposit within diseased vascular districts more efficiently than conventional nanoparticles. PMID:23801070

  11. Indoor/outdoor relationships and mass closure of quasi-ultrafine, accumulation and coarse particles in Barcelona schools

    NASA Astrophysics Data System (ADS)

    Viana, M.; Rivas, I.; Querol, X.; Alastuey, A.; Sunyer, J.; Álvarez-Pedrerol, M.; Bouso, L.; Sioutas, C.

    2014-05-01

    The mass concentration, chemical composition and sources of quasi-ultrafine (quasi-UFP, PM0.25), accumulation (PM0.25-2.5) and coarse mode (PM2.5-10) particles were determined in indoor and outdoor air at 39 schools in Barcelona (Spain). Quasi-UFP mass concentrations measured (25.6 μg m-3 outdoors, 23.4 μg m-3 indoors) are significantly higher than those reported in other studies, and characterised by higher carbonaceous and mineral matter contents and a lower proportion of secondary inorganic ions. Results suggest that quasi-UFPs in Barcelona are affected by local sources in the schools, mainly human activity (e.g. organic material from textiles, etc., contributing 23-46% to total quasi-UFP mass) and playgrounds (in the form of mineral matter, contributing about 9% to the quasi-UFP mass). The particle size distribution patterns of toxicologically relevant metals and major aerosol components was characterised, displaying two modes for most elements and components, and one mode for inorganic salts (ammonium nitrate and sulfate) and elemental carbon (EC). Regarding metals, Ni and Cr were partitioned mainly in quasi-UFPs and could thus be of interest for epidemiological studies, given their high redox properties. Exposure of children to quasi-UFP mass and chemical species was assessed by comparing the concentrations measured at urban background and traffic areas schools. Finally, three main indoor sources across all size fractions were identified by assessing indoor / outdoor ratios (I / O) of PM species used as their tracers: human activity (organic material), cleaning products, paints and plastics (Cl- source), and a metallic mixed source (comprising combinations of Cu, Zn, Co, Cd, Pb, As, V and Cr). Our results support the need to enforce targeted legislation to determine a minimum "safe" distance between major roads and newly built schools to reduce exposure to traffic-derived metals in quasi-UFPs.

  12. Measurements of the evaporation and hygroscopic response of single fine-mode aerosol particles using a Bessel beam optical trap.

    PubMed

    Cotterell, Michael I; Mason, Bernard J; Carruthers, Antonia E; Walker, Jim S; Orr-Ewing, Andrew J; Reid, Jonathan P

    2014-02-01

    A single horizontally-propagating zeroth order Bessel laser beam with a counter-propagating gas flow was used to confine single fine-mode aerosol particles over extended periods of time, during which process measurements were performed. Particle sizes were measured by the analysis of the angular variation of light scattered at 532 nm by a particle in the Bessel beam, using either a probe beam at 405 nm or 633 nm. The vapour pressures of glycerol and 1,2,6-hexanetriol particles were determined to be 7.5 ± 2.6 mPa and 0.20 ± 0.02 mPa respectively. The lower volatility of hexanetriol allowed better definition of the trapping environment relative humidity profile over the measurement time period, thus higher precision measurements were obtained compared to those for glycerol. The size evolution of a hexanetriol particle, as well as its refractive index at wavelengths 532 nm and 405 nm, were determined by modelling its position along the Bessel beam propagation length while collecting phase functions with the 405 nm probe beam. Measurements of the hygroscopic growth of sodium chloride and ammonium sulfate have been performed on particles as small as 350 nm in radius, with growth curves well described by widely used equilibrium state models. These are the smallest particles for which single-particle hygroscopicity has been measured and represent the first measurements of hygroscopicity on fine mode and near-accumulation mode aerosols, the size regimes bearing the most atmospheric relevance in terms of loading, light extinction and scattering. Finally, the technique is contrasted with other single particle and ensemble methods, and limitations are assessed. PMID:24346588

  13. Silica uptake by Spartina—evidence of multiple modes of accumulation from salt marshes around the world

    PubMed Central

    Carey, Joanna C.; Fulweiler, Robinson W.

    2014-01-01

    Silicon (Si) plays a critical role in plant functional ecology, protecting plants from multiple environmental stressors. While all terrestrial plants contain some Si, wetland grasses are frequently found to have the highest concentrations, although the mechanisms driving Si accumulation in wetland grasses remain in large part uncertain. For example, active Si accumulation is often assumed to be responsible for elevated Si concentrations found in wetland grasses. However, life stage and differences in Si availability in the surrounding environment also appear to be important variables controlling the Si concentrations of wetland grasses. Here we used original data from five North American salt marshes, as well as all known published literature values, to examine the primary drivers of Si accumulation in Spartina, a genus of prolific salt marsh grasses found worldwide. We found evidence of multiple modes of Si accumulation in Spartina, with passive accumulation observed in non-degraded marshes where Spartina was native, while rejective accumulation was found in regions where Spartina was invasive. Evidence of active accumulation was found in only one marsh where Spartina was native, but was also subjected to nutrient over-enrichment. We developed a conceptual model which hypothesizes that the mode of Si uptake by Spartina is dependent on local environmental factors and genetic origin, supporting the idea that plant species should be placed along a spectrum of Si accumulation. We hypothesize that Spartina exhibits previously unrecognized phenotypic plasticity with regard to Si accumulation, allowing these plants to respond to changes in marsh condition. These results provide new insight regarding how salt marsh ecosystems regulate Si exchange at the land-sea interface. PMID:24904599

  14. Theory of energetic trapped particle-induced resistive interchange-ballooning modes

    SciTech Connect

    Biglari, H.; Chen, L.

    1986-02-01

    A theory describing the influence of energetic trapped particles on resistive interchange-ballooning modes in tokamaks is presented. It is shown that a population of hot particles trapped in the region of adverse curvature can resonantly interact with and destabilize the resistive interchange mode, which is stable in their absence because of favorable average curvature. The mode is different from the usual resistive interchange mode not only in its destabilization mechanism, but also in that it has a real component to its frequency comparable to the precessional drift frequency of the rapidly circulating energetic species. Corresponding growth rate and threshold conditions for this trapped-particle-driven instability are derived and finite banana width effects are shown to have a stabilizing effect on the mode. Finally, the ballooning/tearing dispersion relation is generalized to include hot particles, so that both the ideal and the resistive modes are derivable in the appropriate limits. 23 refs., 7 figs.

  15. Direct Estimation of Fine and Coarse Mode Particle Parameters from Multiwavelength Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Kolgotin, Alexei; Korenskiy, Mikhail; Veselovskii, Igor; Whiteman, David N.

    2016-06-01

    An approach for the direct estimation (DE) of particle parameters in the fine and coarse mode from multiwavelength lidar measurements is presented. Particle size distributions in both modes are approximated by rectangular functions, so the particle density is estimated directly without solving the inverse problem. The numerical simulation demonstrates that the particle volume in both modes can be estimated from 3β+2α lidar measurements with uncertainty of ~25% for a wide range of size distributions. The technique developed was applied to the observations of NASA GSFC Raman lidar. Comparison of the results obtained with DE and regularization approach applied to the same set of data demonstrates agreement between these two techniques.

  16. Theory of energetic/alpha particle effects on magnetohydrodynamic modes in tokamaks

    SciTech Connect

    Chen, L.; White, R.B.; Rewoldt, G.; Colestock, P.; Rutherford, P.H.; Chen, Y.P.; Ke, F.J.; Tsai, S.T.; Bussac, M.N.

    1989-01-01

    The presence of energetic particles is shown to qualitatively modify the stability properties of ideal as well as resistive magnetohydrodynamic (MHD) modes in tokamaks. Specifically, we demonstrate that, consistent with highpower ICRF heating experiments in JET, high energy trapped particles can effectively stabilize the sawtooth mode, providing a possible route to stable high current tokamak operation. An alternative stabilization scheme employing barely circulating energetic particles is also proposed. Finally, we present analytical and numerical studies on the excitations of high-n MHD modes via transit resonances with circulating alpha particles. 14 refs., 3 figs.

  17. Impact of particles on sediment accumulation in a drinking water distribution system.

    PubMed

    Vreeburg, J H G; Schippers, D; Verberk, J Q J C; van Dijk, J C

    2008-10-01

    Discolouration of drinking water is one of the main reasons customers complain to their water company. Though corrosion of cast iron is often seen as the main source for this problem, the particles originating from the treatment plant play an important and potentially dominant role in the generation of a discolouration risk in drinking water distribution systems. To investigate this thesis a study was performed in a drinking water distribution system. In two similar isolated network areas the effect of particles on discolouration risk was studied with particle counting, the Resuspension Potential Method (RPM) and assessment of the total accumulated sediment. In the 'Control Area', supplied with normal drinking water, the discolouration risk was regenerated within 1.5 year. In the 'Research Area', supplied with particle-free water, this will take 10-15 years. An obvious remedy for controlling the discolouration risk is to improve the treatment with respect to the short peaks that are caused by particle breakthrough. PMID:18789809

  18. COMPARISON OF SULFUR MEASUREMENTS FROM A REGIONAL FINE PARTICLE NETWORK WITH CONCURRENT ACID MODES NETWORK RESULTS

    EPA Science Inventory

    The Fine Particle Network (FPN), a system of fine particle (less than 2.5 um) samplers, was operated at 41 sites selected from the Environmental Protection Agency Acid MODES program during a two year period in 1988-90. he 24-hour sample results included fine particle mass and the...

  19. Accumulative Difference Image Protocol for Particle Tracking in Fluorescence Microscopy Tested in Mouse Lymphonodes

    PubMed Central

    Villa, Carlo E.; Caccia, Michele; Sironi, Laura; D'Alfonso, Laura; Collini, Maddalena; Rivolta, Ilaria; Miserocchi, Giuseppe; Gorletta, Tatiana; Zanoni, Ivan; Granucci, Francesca; Chirico, Giuseppe

    2010-01-01

    The basic research in cell biology and in medical sciences makes large use of imaging tools mainly based on confocal fluorescence and, more recently, on non-linear excitation microscopy. Substantially the aim is the recognition of selected targets in the image and their tracking in time. We have developed a particle tracking algorithm optimized for low signal/noise images with a minimum set of requirements on the target size and with no a priori knowledge of the type of motion. The image segmentation, based on a combination of size sensitive filters, does not rely on edge detection and is tailored for targets acquired at low resolution as in most of the in-vivo studies. The particle tracking is performed by building, from a stack of Accumulative Difference Images, a single 2D image in which the motion of the whole set of the particles is coded in time by a color level. This algorithm, tested here on solid-lipid nanoparticles diffusing within cells and on lymphocytes diffusing in lymphonodes, appears to be particularly useful for the cellular and the in-vivo microscopy image processing in which few a priori assumption on the type, the extent and the variability of particle motions, can be done. PMID:20808918

  20. Energy and frequency dependence of the alpha particle redistribution produced by internal kink modes

    SciTech Connect

    Farengo, R.; Ferrari, H. E.; Garcia-Martinez, P. L.; Firpo, M.-C.; Ettoumi, W.; Lifschitz, A. F.

    2014-08-15

    The redistribution of alpha particles due to internal kink modes is studied. The exact particle trajectories in the total fields, equilibrium plus perturbation, are calculated. The equilibrium has circular cross section and the plasma parameters are similar to those expected in ITER. The alpha particles are initially distributed according to a slowing down distribution function and have energies between 18 keV and 3.5 MeV. The (1, 1), (2, 2), and (2, 1) modes are included and the effect of changing their amplitude and frequency is studied. When only the (1, 1) mode is included, the spreading of high energy (E≳1 MeV) alpha particles increases slowly with the energy and mode frequency. At lower energies, the redistribution is more sensitive to the mode frequency and particle energy. When a (2, 1) mode is added, the spreading increases significantly and particles can reach the edge of the plasma. Trapped particles are the most affected and the redistribution parameter can have maxima above 1 MeV, depending on the mode frequency. These results can have important implications for ash removal.

  1. Onset condition of the subcritical geodesic acoustic mode instability in the presence of energetic-particle-driven geodesic acoustic mode

    NASA Astrophysics Data System (ADS)

    Itoh, K.; Itoh, S.-I.; Kosuga, Y.; Lesur, M.; Ido, T.

    2016-05-01

    An analytic model is developed for understanding the abrupt onset of geodesic acoustic mode (GAM) in the presence of chirping energetic-particle-driven GAM (EGAM). This abrupt excitation phenomenon has been observed on LHD plasma. Threshold conditions for the onset of abrupt growth of GAM are derived, and the period doubling phenomenon is explained. The phase relation between the mother mode (EGAM) and the daughter mode (GAM) is also discussed. This result contributes to the understanding of "trigger problems" of laboratory and nature plasmas.

  2. Suppression of 1/f Noise in Accumulation Mode FD-SOI MOSFETs on Si(100) and (110) Surfaces

    SciTech Connect

    Cheng, W.; Gaubert, P.; Teramoto, A.; Tye, C.; Sugawa, S.; Ohmi, T.

    2009-04-23

    In this paper, a new approach to reduce the 1/f noise levels in the MOSFETs on varied silicon orientations, such as Si(100) and (110) surfaces, has been carried out. We focus on the Accumulation-mode (AM) FD-SOI device structure and demonstrate that the 1/f noise levels in this AM FD-SOI MOSFETs are obviously reduced on both the Si(100) and (110) surfaces.

  3. Small-action Particles in a Tokamak in the Presence of an n = 1 Mode

    SciTech Connect

    R.B. White; V.V. Lutsenko; Ya. I. Kolesnichenko; Yu. V. Yakovenko

    1999-11-01

    It is found that an m = n = 1 mode with the amplitude exceeding a certain threshold can lead to stochastic motion of energetic ions in tokamaks, the large orbit width particles (potatoes) being most easily affected. An n = 1 mode can redistribute particles also in the absence of stochasticity but only when the perturbation is quickly switched on/off, e.g., due to sawtooth crash. In the latter case, the perturbation results in regular motion of particles around a certain helical orbit, at which a resonance driven by the mode but having no amplitude threshold takes place.

  4. Wave-vector dispersion versus angular-momentum dispersion of collective modes in small metal particles

    NASA Astrophysics Data System (ADS)

    Ekardt, W.

    1987-09-01

    The wave-vector dispersion of collective modes in small particles is investigated within the time-dependent local-density approximation as applied to a self-consistent jellium particle. It is shown that the dispersion of the volume plasmons can be understood from that in an infinite electron gas. For a given multipole an optimum wave vector exists for the quasiresonant excitation of the volume mode but not for the surface mode. It is pointed out that-for the volume modes-the hydrodynamic approximation gives a reasonable first guess for the relation between frequencies and size-quantized wave vectors.

  5. Global particle-in-cell simulations of plasma pressure effects on Alfvenic modes

    SciTech Connect

    Mishchenko, Alexey; Koenies, Axel; Hatzky, Roman

    2011-01-15

    Global linear gyrokinetic particle-in-cell simulations of electromagnetic modes in realistic tokamak geometry are reported. The effect of plasma pressure on Alfvenic modes is studied. It is shown that the fast-particle pressure can considerably affect the shear Alfven wave continuum structure and hence the toroidicity-induced gap in the continuum. It is also found that the energetic ions can substantially reduce the growth rate of the ballooning modes (and perhaps completely stabilize them in a certain parameter range). Ballooning modes are found to be the dominant instabilities if the bulk-plasma pressure gradient is large enough.

  6. Global Hybrid Simulations of Energetic Particle-driven Modes in Toroidal Plasmas

    SciTech Connect

    G.Y. Fu; J. Breslau; E. Fredrickson; W. Park; H.R. Strauss

    2004-12-14

    Global hybrid simulations of energetic particle-driven MHD modes have been carried out for tokamaks and spherical tokamaks using the hybrid code M3D. The numerical results for the National Spherical Tokamak Experiments (NSTX) show that Toroidal Alfven Eigenmodes are excited by beam ions with their frequencies consistent with the experimental observations. Nonlinear simulations indicate that the n=2 mode frequency chirps down as the mode moves out radially. For ITER, it is shown that the alpha-particle effects are strongly stabilizing for internal kink mode when central safety factor q(0) is sufficiently close to unity. However, the elongation of ITER plasma shape reduces the stabilization significantly.

  7. Gyrokinetic particle simulations of kinetic ballooning mode in tokamak pedestal

    NASA Astrophysics Data System (ADS)

    Holod, Ihor

    2014-10-01

    The pedestal height and width in tokamak H-mode operation are widely believed to be constrained by mesoscale peeling-ballooning modes and microscopic kinetic ballooning modes (KBM). However, direct evidences of the KBM turbulence in pedestal are very limited. The role of the drift-Alfvenic microturbulence during the pedestal recovery period is not clear. Here we use gyrokinetic toroidal code (GTC) to study the edge instability of a DIII-D discharge #131997 using realistic geometry and plasma profiles and focusing on the pedestal region with steep pressure gradient. First, electrostatic simulations find a reactive trapped electron mode with an unusual eigenmode structure, which peaks at the poloidal angle θ = +/- π /2. The electron collisions decrease the growth rate by about one-half. Next, the plasma pressure is scanned in GTC electromagnetic simulations to identify the boundary for the KBM onset. At the finite electron beta an electromagnetic instability is found with KBM characteristics. The linear growth rate increases with βe and the mode propagation is in the ion diamagnetic direction. Nonlinear simulations of the KBM turbulence will also be presented. Work supported by DOE Grant DE-SC0010416, and in collaborations with GTC team.

  8. Normal modes of prion proteins: from native to infectious particle.

    PubMed

    Samson, Abraham O; Levitt, Michael

    2011-03-29

    Prion proteins (PrP) are the infectious agent in transmissible spongiform encephalopathies (i.e., mad cow disease). To be infectious, prion proteins must undergo a conformational change involving a decrease in α-helical content along with an increase in β-strand content. This conformational change was evaluated by means of elastic normal modes. Elastic normal modes show a diminution of two α-helices by one and two residues, as well as an extension of two β-strands by three residues each, which could instigate the conformational change. The conformational change occurs in a region that is compatible with immunological studies, and it is observed more frequently in mutant prions that are prone to conversion than in wild-type prions because of differences in their starting structures, which are amplified through normal modes. These findings are valuable for our comprehension of the conversion mechanism associated with the conformational change in prion proteins. PMID:21338080

  9. Simulation study of high-frequency energetic particle driven geodesic acoustic mode

    SciTech Connect

    Wang, Hao Ido, Takeshi; Osakabe, Masaki; Todo, Yasushi

    2015-09-15

    High-frequency energetic particle driven geodesic acoustic modes (EGAM) observed in the large helical device plasmas are investigated using a hybrid simulation code for energetic particles and magnetohydrodynamics (MHD). Energetic particle inertia is incorporated in the MHD momentum equation for the simulation where the beam ion density is comparable to the bulk plasma density. Bump-on-tail type beam ion velocity distribution created by slowing down and charge exchange is considered. It is demonstrated that EGAMs have frequencies higher than the geodesic acoustic modes and the dependence on bulk plasma temperature is weak if (1) energetic particle density is comparable to the bulk plasma density and (2) charge exchange time (τ{sub cx}) is sufficiently shorter than the slowing down time (τ{sub s}) to create a bump-on-tail type distribution. The frequency of high-frequency EGAM rises as the energetic particle pressure increases under the condition of high energetic particle pressure. The frequency also increases as the energetic particle pitch angle distribution shifts to higher transit frequency. It is found that there are two kinds of particles resonant with EGAM: (1) trapped particles and (2) passing particles with transit frequency close to the mode frequency. The EGAMs investigated in this work are destabilized primarily by the passing particles whose transit frequencies are close to the EGAM frequency.

  10. Modeling of long range frequency sweeping for energetic particle modes

    SciTech Connect

    Nyqvist, R. M.; Breizman, B. N.

    2013-04-15

    Long range frequency sweeping events are simulated numerically within a one-dimensional, electrostatic bump-on-tail model with fast particle sources and collisions. The numerical solution accounts for fast particle trapping and detrapping in an evolving wave field with a fixed wavelength, and it includes three distinct collisions operators: Drag (dynamical friction on the background electrons), Krook-type collisions, and velocity space diffusion. The effects of particle trapping and diffusion on the evolution of holes and clumps are investigated, and the occurrence of non-monotonic (hooked) frequency sweeping and asymptotically steady holes is discussed. The presented solution constitutes a step towards predictive modeling of frequency sweeping events in more realistic geometries.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Atmospheric fate of nuclei-mode particles estimated from the number concentrations and chemical composition of particles measured at roadside and background sites

    NASA Astrophysics Data System (ADS)

    Fushimi, Akihiro; Hasegawa, Shuichi; Takahashi, Katsuyuki; Fujitani, Yuji; Tanabe, Kiyoshi; Kobayashi, Shinji

    Number concentrations and size-resolved chemical compositions of atmospheric particles at a roadside site in Kawasaki City, Japan, and a background site 200 m away were measured in winter to estimate the atmospheric fate of nuclei-mode particles emitted from vehicles. Measurements with a scanning mobility particle sizer showed a sharp peak in nuclei-mode particles with a modal diameter of around 0.020 μm at the roadside site; in contrast, no peak for nuclei-mode particles was observed at the background site. For chemical analysis, size-resolved particles were sampled by low-pressure impactors. Carbon analysis suggested that diesel exhaust particles contributed to both the roadside and background Stage 1 (S1; 0.030-0.060 μm) particles. The ratios of organic carbon (OC) to total carbon (TC) increased for smaller particles, and were 28% and 51% for the roadside and the background S1 particles, respectively. It is likely that the OC/TC ratio for nuclei-mode particles was larger than for the S1 particles, and that OC was one of the major constituents of the nuclei-mode particles at the roadside site. From this result and the greater Kelvin effect for smaller particles, it is likely that nuclei-mode particles in the roadside atmosphere are more volatile than the S1 particles. Organic analysis of the size-resolved particles suggested that lubricating oil from vehicles affected the organic composition of both the roadside and background S1 particles, and that C 33n-alkane and more volatile organic compounds in the S1 particles partially evaporated in the atmosphere following the emission of the particles from diesel vehicles. It is likely that evaporation of the constituents (or possibly coagulation with pre-existing particles after shrinking by partial evaporation) of the nuclei-mode particles in the atmosphere was responsible for the absence of nuclei-mode particles in the background atmosphere.

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

    NASA Astrophysics Data System (ADS)

    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, 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.

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

    NASA Astrophysics Data System (ADS)

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

    2005-06-01

    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, 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.

  15. EFFECTS OF INTRATRACHEALLY ADMINISTERED COARSE MODE PARTICLES ON RESPIRATORY TRACT INFECTION IN MICE

    EPA Science Inventory

    Because coarse mode particles are rarely studied in their existing size ranges (greatest mass about 5-7 micrometers, aerodynamic diameter), the authors investigated the effects of four such particles, quartz, ferric oxide, calcium carbonate, and sodium feldspar, on host defenses ...

  16. Fast Particle Effects on the Internal Kink, Fishbone and Alfven Modes

    SciTech Connect

    N.N. Gorelenkov; S. Bernabei; C.Z. Cheng; G.Y. Fu; K. Hill; S. Kaye; G.J. Kramer; Y. Kusama; K. Shinohara; R. Nazikian; T. Ozeki; W. Park

    2000-11-15

    The issues of linear stability of low frequency perturbative and nonperturbative modes in advanced tokamak regimes are addressed based on recent developments in theory, computational methods, and progress in experiments. Perturbative codes NOVA and ORBIT are used to calculate the effects of TAEs on fast particle population in spherical tokamak NSTX. Nonperturbative analysis of chirping frequency modes in experiments on TFTR and JT-60U is presented using the kinetic code HINST, which identified such modes as a separate branch of Alfven modes - resonance TAE (R-TAE). Internal kink mode stability in the presence of fast particles is studied using the NOVA code and hybrid kinetic-MHD nonlinear code M3D.

  17. In–out asymmetry of divertor particle flux in H-mode with edge localized modes on EAST

    NASA Astrophysics Data System (ADS)

    Liu, J. B.; Guo, H. Y.; Wang, L.; Xu, G. S.; Xia, T. Y.; Liu, S. C.; Xu, X. Q.; Li, Jie; Chen, L.; Yan, N.; Wang, H. Q.; Xu, J. C.; Feng, W.; Shao, L. M.; Deng, G. Z.; Liu, H.; EAST Probe Team

    2016-06-01

    The in–out divertor asymmetry in the Experimental Advanced Superconducting Tokamak (EAST), as manifested by particle fluxes measured by the divertor triple Langmuir probe arrays, is significantly enhanced during type-I edge localized modes (ELMs), favoring the inner divertor in lower single null (LSN) for the normal toroidal field (B t) direction, i.e. with the ion B  ×  \

  18. Finite element computations of resonant modes for small magnetic particles

    NASA Astrophysics Data System (ADS)

    Forestiere, C.; d'Aquino, M.; Miano, G.; Serpico, C.

    2009-04-01

    The oscillations of a chain of ferromagnetic nanoparticles around a saturated spatially uniform equilibrium are analyzed by solving the linearized Landau-Lifshitz-Gilbert (LLG) equation. The linearized LLG equation is recast in the form of a generalized eigenvalue problem for suitable self-adjoint operators connected to the micromagnetic effective field, which accounts for exchange, magnetostatic, anisotropy, and Zeeman interactions. The generalized eigenvalue problem is solved numerically by the finite element method, which allows one to treat accurately complex geometries and preserves the structural properties of the continuum problem. The natural frequencies and the spatial distribution of the mode amplitudes are computed for chains composed of several nanoparticles (sphere and ellipsoid). The effects of the interaction between the nanoparticles and the limit of validity of the point dipole approximation are discussed.

  19. Commuter exposure to inhalable, thoracic and alveolic particles in various transportation modes in Delhi.

    PubMed

    Kumar, Pramod; Gupta, N C

    2016-01-15

    A public health concern is to understand the linkages between specific pollution sources and adverse health impacts. Commuting can be viewed as one of the significant-exposure activity in high-vehicle density areas. This paper investigates the commuter exposure to inhalable, thoracic and alveolic particles in various transportation modes in Delhi, India. Air pollution levels are significantly contributed by automobile exhaust and also in-vehicle exposure can be higher sometime than ambient levels. Motorcycle, auto rickshaw, car and bus were selected to study particles concentration along two routes in Delhi between Kashmere Gate and Dwarka. The bus and auto rickshaw were running on compressed natural gas (CNG) while the car and motorcycle were operated on gasoline fuel. Aerosol spectrometer was employed to measure inhalable, thoracic and alveolic particles during morning and evening rush hours for five weekdays. From the study, we observed that the concentration levels of these particles were greatly influenced by transportation modes. Concentrations of inhalable particles were found higher during morning in auto rickshaw (332.81 ± 90.97 μg/m(3)) while the commuter of bus exhibited higher exposure of thoracic particles (292.23 ± 110.45 μg/m(3)) and car commuters were exposed to maximum concentrations of alveolic particles (222.37 ± 26.56 μg/m(3)). We observed that in evening car commuters experienced maximum concentrations of all sizes of particles among the four commuting modes. Interestingly, motorcycle commuters were exposed to lower levels of inhalable and thoracic particles during morning and evening hours as compared to other modes of transport. The mean values were found greater than the median values for all the modes of transport suggesting that positive skewed distributions are characteristics of naturally occurring phenomenon. PMID:26439646

  20. Modes of reproduction and the accumulation of deleterious mutations with multiplicative fitness effects.

    PubMed Central

    Haccou, Patsy; Schneider, Maria Victoria

    2004-01-01

    Mutational load depends not only on the number and nature of mutations but also on the reproductive mode. Traditionally, only a few specific reproductive modes are considered in the search of explanations for the maintenance of sex. There are, however, many alternatives. Including these may give radically different conclusions. The theory on deterministic deleterious mutations states that in large populations segregation and recombination may lead to a lower load of deleterious mutations, provided that there are synergistic interactions. Empirical research suggests that effects of deleterious mutations are often multiplicative. Such situations have largely been ignored in the literature, since recombination and segregation have no effect on mutation load in the absence of epistasis. However, this is true only when clonal reproduction and sexual reproduction with equal male and female ploidy are considered. We consider several alternative reproductive modes that are all known to occur in insects: arrhenotoky, paternal genome elimination, apomictic thelytoky, and automictic thelytoky with different cytological mechanisms to restore diploidy. We give a method that is based on probability-generating functions, which provides analytical and numerical results on the distributions of deleterious mutations. Using this, we show that segregation and recombination do make a difference. Furthermore, we prove that a modified form of Haldane's principle holds more generally for thelytokous reproduction. We discuss the implications of our results for evolutionary transitions between different reproductive modes in insects. Since the strength of Muller's ratchet is reduced considerably for several forms of automictic thelytoky, many of our results are expected to be also valid for initially small populations. PMID:15020489

  1. Eddy fluxes of nuclei mode particles to pine forest during BEARPEX'09

    NASA Astrophysics Data System (ADS)

    Vong, R. J.; Covert, D. S.

    2010-12-01

    BEARPEX'09 was conducted for seven weeks during June and July 2009 at a forested site located near Blodgett Forest, California. Simultaneous and continuous data were collected at 2 Hz by a particle counter (wCPC: TSI) that sensed the sum of all particles (0.010 ≤ Dp) and a sonic anemometer (ATI) for the determination of particle ‘eddy correlation’ fluxes. We also operated an electrical mobility (TSI DMA) instrument for determining the aerosol size spectra at 30 minute intervals. We anticipated that there would be issues associated with particle hygroscopic growth and particle counting but these factors were not important for wCPC eddy fluxes. The wCPC co-spectra were similar [|#11#|]to those for heat and vapor suggesting that [|#11#|]most of the nuclei mode particle flux was captured by this 2 Hz sampling rate. However, the wCPC would be sensitive to any ultrafine particles from gas-to-particle conversion of biogenic emissions and to any nuclei mode particles from a nearby generator. Northerly winds that occurred primarily at night sometimes brought generator emissions to the wCPC and resulted in short term concentration peaks. Since this type of advection and non-stationarity violate the assumptions for eddy correlation, we developed [|#11#|]screening criteria to identify these wCPC peaks by calculating variability on several scales (τ > 100 sec, < 100 sec, and scales < 10 sec). After such screening we still had 1246 total 30-minute wCPC eddy flux observations at varying times of day for analysis of nuclei mode particle deposition. These wCPC eddy flux results for BEARPEX 2009 are presented here in Figure 1 as deposition velocities (Vd). The observed wCPC fluxes were consistently downwards; Vd was typically 0.25 cm/sec during afternoon. The DMA size distributions showed primarily nuclei mode particles (0.030 ≤ Dp ≤ 0.100 µm); there were not many particles between 0.010 ≤ Dp ≤ 0.030 µm. From both the lack of particles smaller than 30 nm from the

  2. Ultrasonic trapping of small particles by sharp edges vibrating in a flexural mode

    NASA Astrophysics Data System (ADS)

    Hu, Junhui; Yang, Jianbo; Xu, Jun

    2004-12-01

    Ultrasonic trapping of small particles by sharp edges vibrating in a flexural mode is reported. Two rectangular metal plates with a sharp edge are mechanically excited to vibrate in a flexural mode by the piezoelectric rings which are pressed between them by a bolt structure. Small particles such as mint seeds and flying color seeds can be attracted to the sharp edges of the plates. Relationship between input power applied to the piezoelectric rings and the number of trapped particles is experimentally investigated for mint seeds and flying color seeds in water and air. The result shows that for a given type of particle, there exists an input power at which the number of trapped particles is a maximum. Mechanism analysis shows that nodes or antinodes of acoustic pressure of the sound field near the sharp edges are responsible for the trapping.

  3. Microbial community composition of polyhydroxyalkanoate-accumulating organisms in full-scale wastewater treatment plants operated in fully aerobic mode.

    PubMed

    Oshiki, Mamoru; Onuki, Motoharu; Satoh, Hiroyasu; Mino, Takashi

    2013-01-01

    The removal of biodegradable organic matter is one of the most important objectives in biological wastewater treatments. Polyhydroxyalkanoate (PHA)-accumulating organisms (PHAAOs) significantly contribute to the removal of biodegradable organic matter; however, their microbial community composition is mostly unknown. In the present study, the microbial community composition of PHAAOs was investigated at 8 full-scale wastewater treatment plants (WWTPs), operated in fully aerobic mode, by fluorescence in situ hybridization (FISH) analysis and post-FISH Nile blue A (NBA) staining techniques. Our results demonstrated that 1) PHAAOs were in the range of 11-18% in the total number of cells, and 2) the microbial community composition of PHAAOs was similar at the bacterial domain/phylum/class/order level among the 8 full-scale WWTPs, and dominant PHAAOs were members of the class Alphaproteobacteria and Betaproteobacteria. The microbial community composition of α- and β-proteobacterial PHAAOs was examined by 16S rRNA gene clone library analysis and further by applying a set of newly designed oligonucleotide probes targeting 16S rRNA gene sequences of α- or β-proteobacterial PHAAOs. The results demonstrated that the microbial community composition of PHAAOs differed in the class Alphaproteobacteria and Betaproteobacteria, which possibly resulted in a different PHA accumulation capacity among the WWTPs (8.5-38.2 mg-C g-VSS(-1) h(-1)). The present study extended the knowledge of the microbial diversity of PHAAOs in full-scale WWTPs operated in fully aerobic mode. PMID:23257912

  4. Radial Particle Flux in the SOL of DIII-D During ELMing H-Mode

    SciTech Connect

    Leonard, A W; Boedo, J A; Groth, M; Lipschultz, B L; Porter, G D; Rudakov, D L; Whyte, D G

    2006-06-01

    The radial particle flux in the scrape-off-layer (SOL) during ELMing H-mode is examined in DIII-D as a function of density. The global radial particle flux in the outboard far SOL is determined by a window frame technique. Between ELMs the outboard far SOL particle flux increases strongly with density but remains similar to the particle flux across the separatrix as estimated by the pedestal density and temperature gradients. At low density the steep density gradient of the pedestal extends up to 2 cm outside the separatrix. At high density the density gradient flattens just outside the separatrix making this region critical for assessment of the far SOL particle flux. During ELMs the far SOL particle flux becomes localized to the outboard midplane and the assumptions for the window frame analysis break down. Implications for scaling of main chamber wall particle flux and pedestal fueling are explored.

  5. Continuous Influenza Virus Production in Cell Culture Shows a Periodic Accumulation of Defective Interfering Particles

    PubMed Central

    Pflugmacher, Antje; Behrendt, Ilona; Jordan, Ingo; Flockerzi, Dietrich; Genzel, Yvonne; Reichl, Udo

    2013-01-01

    Influenza viruses are a major public health burden during seasonal epidemics and a continuous threat due to their potential to cause pandemics. Annual vaccination provides the best protection against the contagious respiratory illness caused by influenza viruses. However, the current production capacities for influenza vaccines are insufficient to meet the increasing demands. We explored the possibility to establish a continuous production process for influenza viruses using the duck-derived suspension cell line AGE1.CR. A two-stage bioreactor setup was designed in which cells were cultivated in a first stirred tank reactor where an almost constant cell concentration was maintained. Cells were then constantly fed to a second bioreactor where virus infection and replication took place. Using this two-stage reactor system, it was possible to continuously produce influenza viruses. Surprisingly, virus titers showed a periodic increase and decrease during the run-time of 17 days. These titer fluctuations were caused by the presence of defective interfering particles (DIPs), which we detected by PCR. Mathematical modeling confirmed this observation showing that constant virus titers can only emerge in the absence of DIPs. Even with very low amounts of DIPs in the seed virus and very low rates for de novo DIP generation, defective viruses rapidly accumulate and, therefore, represent a serious challenge for continuous vaccine production. Yet, the continuous replication of influenza virus using a two-stage bioreactor setup is a novel tool to study aspects of viral evolution and the impact of DIPs. PMID:24039749

  6. Effect of dynamical friction on nonlinear energetic particle modes

    SciTech Connect

    Lilley, M. K.; Breizman, B. N.; Sharapov, S. E.

    2010-09-15

    A fully nonlinear model is developed for the bump-on-tail instability including the effects of dynamical friction (drag) and velocity space diffusion on the energetic particles driving the wave. The results show that drag provides a destabilizing effect on the nonlinear evolution of waves. Specifically, in the early nonlinear phase of the instability, the drag facilitates the explosive scenario of the wave evolution, leading to the creation of phase space holes and clumps that move away from the original eigenfrequency. Later in time, the electric field associated with a hole is found to be enhanced by the drag, whereas for a clump it is reduced. This leads to an asymmetry of the frequency evolution between holes and clumps. The combined effect of drag and diffusion produces a diverse range of nonlinear behaviors including hooked frequency chirping, undulating, and steady state regimes. An analytical model is presented, which explains the aforementioned diversity. A continuous production of hole-clump pairs in the absence of collisions is also observed.

  7. Acute toxicity and accumulation of ZnO NPs in Ceriodaphnia dubia: Relative contributions of dissolved ions and particles.

    PubMed

    Bhuvaneshwari, M; Iswarya, V; Nagarajan, R; Chandrasekaran, N; Mukherjee, Amitava

    2016-08-01

    Although the ecotoxicological effects of various metal oxide nanoparticles on aquatic organisms are being actively studied, the contributions of particles and dissolved ions towards toxicity are still not well understood. The current study aims to assess the contribution of ZnO NP(particle) and ZnO NP(ion) to the overall toxicity and accumulation of ZnO NP(total) in Ceriodaphnia dubia. The aggregation and dissolution kinetics were studied for three different sizes (50nm, 100nm and bulk) of ZnO particles at 0.05, 0.12, 0.25 and 0.5mg/L concentrations in the sterile lake water medium at 6, 12, 24, and 48h intervals. The 48h LC50 of ZnO NP(total) was found to be 0.431, 0.605 and 0.701mg/L for 50, 100nm and bulk particles exposure. However, LC50 of Zn(ion) was found to be 1.048, 1.343 and 2.046mg/L for dissolved ions from different sizes (50nm, 100nm, and bulk) of ZnO particles. At LC50 concentration, the accumulation of 90-95% was noted for the NP(particles) across the sizes employed, while only about 4-5% contribution was from the NP(ion) to the overall accumulation NP(total). The relative contribution of ZnO NP(ion) to overall toxicity and accumulation was found to be lesser than that of ZnO NP(particles) across the sizes used in the study. PMID:27424101

  8. Vertical Modes and Discrete Instabilities in Two-Dimensional Dust Particle Clusters

    NASA Astrophysics Data System (ADS)

    Qiao, Ke; Carmona-Reyes, Jorge; Kong, Jie; Matthews, Lorin; Hyde, Truell

    2013-10-01

    The coupling observed between horizontal and vertical wave modes in large plasma crystals and their resulting instability formation are current topics of interest, both theoretically and experimentally. Similarly, horizontal and vertical normal modes in finite dust clusters have been examined theoretically but to date, only horizontal modes have been experimentally observed. In this research, dust clusters are formed within a modified GEC rf reference cell, using a glass box placed on the lower powered electrode to provide horizontal confinement. The resulting thermal motion of the dust particles is tracked and analyzed. Using the power spectra obtained, both horizontal and vertical normal modes are identified and discrete instabilities as predicted theoretically are shown to be induced due to the coupling between the horizontal and vertical modes.

  9. Experimental determination of the particle motions associated with the low order acoustic modes in enclosures

    NASA Technical Reports Server (NTRS)

    Byrne, K. P.; Marshall, S. E.

    1983-01-01

    A procedure for experimentally determining, in terms of the particle motions, the shapes of the low order acoustic modes in enclosures is described. The procedure is based on finding differentiable functions which approximate the shape functions of the low order acoustic modes when these modes are defined in terms of the acoustic pressure. The differentiable approximating functions are formed from polynomials which are fitted by a least squares procedure to experimentally determined values which define the shapes of the low order acoustic modes in terms of the acoustic pressure. These experimentally determined values are found by a conventional technique in which the transfer functions, which relate the acoustic pressures at an array of points in the enclosure to the volume velocity of a fixed point source, are measured. The gradient of the function which approximates the shape of a particular mode in terms of the acoustic pressure is evaluated to give the mode shape in terms of the particle motion. The procedure was tested by using it to experimentally determine the shapes of the low order acoustic modes in a small rectangular enclosure.

  10. Experimental aspects of effects of high-energy particles on Alfven modes

    SciTech Connect

    Heidbrink, W.W.

    1994-10-01

    Global Alfven modes are observed in a number of tokamaks, including DIII-D and TFTR. Instabilities occur during neutral-beam injection and during fast-wave ICRF heating, and may recently have been observed during alpha-particle heating. Identification of toroidicity-induced Alfven eigenmodes (TAE) is based primarily on the scaling of the real frequency of the mode. Other modes, including the beta-induced Alfven eigenmode (BAE), are also observed. The stability threshold of TAE modes agree (to within a factor of two) with theoretical predictions. Toroidal mode numbers of n = 2-6 are usually most unstable, as theoretically expected. Measurements of the poloidal and radial mode structure are consistent with theoretical predictions, but the uncertainties are large. Both TAE and BAE modes can cause large, concentrated losses of fast ions. Phenomenologically, beam-driven Alfven modes usually {open_quotes}saturate{close_quotes} through bursts that expel beam ions, while modes observed during ICPF heating approach a steady saturation amplitude.

  11. Exploring nutritional modes of cultivation for enhancing lipid accumulation in microalgae.

    PubMed

    Ratha, Sachitra Kumar; Babu, Santosh; Renuka, Nirmal; Prasanna, Radha; Prasad, Rachapudi Badari Narayana; Saxena, Anil Kumar

    2013-05-01

    The objective of this study was to identify the most promising nutritional mode of growth for enhanced biomass and lipid productivity in a set of twenty microalgal strains, grown under photoautotrophic and mixotrophic/heterotrophic conditions using 2% glucose as carbon source. These included four cyanobacterial strains (Cyanosarcina, Phormidium, Nostoc and Anabaena) and sixteen green algae belonging to six genera (five strains each of Chlorella and Chlorococcum, two of Scenedesmus and one each of Chlamydomonas, Kirchneria, Bracteacoccus and Ulothrix). Lipid productivity ranged from 2-13% under photoautotrophic conditions, 1.7-32% under mixotrophic conditions and 0.9-20% under heterotrophic conditions. MIC-G5 Chlorella sp. followed by MIC-G11 Chlorella sp. exhibited the highest cellular lipid content (355 and 271 μg/ml) and lipid productivity of 32% and 28% respectively in mixotrophic condition. In the glucose supplemented conditions (heterotrophic), a significant reduction in PUFA from 25.1 to 9.4, 29.2 to 12.4 and 44.7 to 10.2 was observed in MIC-G4, MIC-G5 and MIC-G11, respectively. A remarkable enhancement of 33-70% in SFA was recorded under mixotrophic conditions. As the quality of biodiesel is based on high SFA and low PUFA, our results illustrate the significance of glucose supplemented condition as a promising strategy for generating high value biodiesel from algae. PMID:22736510

  12. Ultrastructural Characterization of Turnip Mosaic Virus-Induced Cellular Rearrangements Reveals Membrane-Bound Viral Particles Accumulating in Vacuoles

    PubMed Central

    Wan, Juan; Basu, Kaustuv; Mui, Jeannie; Vali, Hojatollah; Zheng, Huanquan

    2015-01-01

    ABSTRACT Positive-strand RNA [(+) RNA] viruses remodel cellular membranes to facilitate virus replication and assembly. In the case of turnip mosaic virus (TuMV), the viral membrane protein 6K2 plays an essential role in endomembrane alterations. Although 6K2-induced membrane dynamics have been widely studied by confocal microscopy, the ultrastructure of this remodeling has not been extensively examined. In this study, we investigated the formation of TuMV-induced membrane changes by chemical fixation and high-pressure freezing/freeze substitution (HPF/FS) for transmission electron microscopy at different times of infection. We observed the formation of convoluted membranes connected to rough endoplasmic reticulum (rER) early in the infection process, followed by the production of single-membrane vesicle-like (SMVL) structures at the midstage of infection. Both SMVL and double-membrane vesicle-like structures with electron-dense cores, as well as electron-dense bodies, were found late in the infection process. Immunogold labeling results showed that the vesicle-like structures were 6K2 tagged and suggested that only the SMVL structures were viral RNA replication sites. Electron tomography (ET) was used to regenerate a three-dimensional model of these vesicle-like structures, which showed that they were, in fact, tubules. Late in infection, we observed filamentous particle bundles associated with electron-dense bodies, which suggests that these are sites for viral particle assembly. In addition, TuMV particles were observed to accumulate in the central vacuole as membrane-associated linear arrays. Our work thus unravels the sequential appearance of distinct TuMV-induced membrane structures for viral RNA replication, viral particle assembly, and accumulation. IMPORTANCE Positive-strand RNA viruses remodel cellular membranes for different stages of the infection process, such as protein translation and processing, viral RNA synthesis, particle assembly, and virus

  13. Influence of surface morphology on the immersion mode ice nucleation efficiency of hematite particles

    SciTech Connect

    Hiranuma, N.; Hoffmann, N.; Kiselev, A.; Dreyer, A.; Zhang, K.; Kulkarni, G.; Koop, T.; Möhler, O.

    2014-01-01

    In this paper, the effect of the morphological modification of aerosol particles with respect to heterogeneous ice nucleation is comprehensively investigated for laboratory-generated hematite particles as a model substrate for atmospheric dust particles. The surface-area-scaled ice nucleation efficiencies of monodisperse cubic hematite particles and milled hematite particles were measured with a series of expansion cooling experiments using the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) cloud simulation chamber. Complementary offline characterization of physico-chemical properties of both hematite subsets were also carried out with scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, dynamic light scattering (DLS), and an electro-kinetic particle charge detector to further constrain droplet-freezing measurements of hematite particles. Additionally, an empirical parameterization derived from our laboratory measurements was implemented in the single-column version of the Community Atmospheric Model version 5 (CAM5) to investigate the model sensitivity in simulated ice crystal number concentration on different ice nucleation efficiencies. From an experimental perspective, our results show that the immersion mode ice nucleation efficiency of milled hematite particles is almost an order of magnitude higher at -35.2 °C < T < -33.5 °C than that of the cubic hematite particles, indicating a substantial effect of morphological irregularities on immersion mode freezing. Our modeling results similarly show that the increased droplet-freezing rates of milled hematite particles lead to about one order magnitude higher ice crystal number in the upper troposphere than cubic hematite particles. Finally and overall, our results suggest that the surface irregularities and associated active sites lead to greater ice activation through droplet freezing.

  14. Exposure to ultrafine particles and PM 2.5 in four Sydney transport modes

    NASA Astrophysics Data System (ADS)

    Knibbs, Luke D.; de Dear, Richard J.

    2010-08-01

    Concentrations of ultrafine (<0.1 μm) particles (UFPs) and PM 2.5 (<2.5 μm) were measured whilst commuting along a similar route by train, bus, ferry and automobile in Sydney, Australia. One trip on each transport mode was undertaken during both morning and evening peak hours throughout a working week, for a total of 40 trips. Analyses comprised one-way ANOVA to compare overall (i.e. all trips combined) geometric mean concentrations of both particle fractions measured across transport modes, and assessment of both the correlation between wind speed and individual trip means of UFPs and PM 2.5, and the correlation between the two particle fractions. Overall geometric mean concentrations of UFPs and PM 2.5 ranged from 2.8 (train) to 8.4 (bus) × 10 4 particles cm -3 and 22.6 (automobile) to 29.6 (bus) μg m -3, respectively, and a statistically significant difference ( p < 0.001) between modes was found for both particle fractions. Individual trip geometric mean concentrations were between 9.7 × 10 3 (train) and 2.2 × 10 5 (bus) particles cm -3 and 9.5 (train) to 78.7 (train) μg m -3. Estimated commuter exposures were variable, and the highest return trip mean PM 2.5 exposure occurred in the ferry mode, whilst the highest UFP exposure occurred during bus trips. The correlation between fractions was generally poor, and in keeping with the duality of particle mass and number emissions in vehicle-dominated urban areas. Wind speed was negatively correlated with, and a generally poor determinant of, UFP and PM 2.5 concentrations, suggesting a more significant role for other factors in determining commuter exposure.

  15. Microbial Community Composition of Polyhydroxyalkanoate-Accumulating Organisms in Full-Scale Wastewater Treatment Plants Operated in Fully Aerobic Mode

    PubMed Central

    Oshiki, Mamoru; Onuki, Motoharu; Satoh, Hiroyasu; Mino, Takashi

    2013-01-01

    The removal of biodegradable organic matter is one of the most important objectives in biological wastewater treatments. Polyhydroxyalkanoate (PHA)-accumulating organisms (PHAAOs) significantly contribute to the removal of biodegradable organic matter; however, their microbial community composition is mostly unknown. In the present study, the microbial community composition of PHAAOs was investigated at 8 full-scale wastewater treatment plants (WWTPs), operated in fully aerobic mode, by fluorescence in situ hybridization (FISH) analysis and post-FISH Nile blue A (NBA) staining techniques. Our results demonstrated that 1) PHAAOs were in the range of 11–18% in the total number of cells, and 2) the microbial community composition of PHAAOs was similar at the bacterial domain/phylum/class/order level among the 8 full-scale WWTPs, and dominant PHAAOs were members of the class Alphaproteobacteria and Betaproteobacteria. The microbial community composition of α- and β-proteobacterial PHAAOs was examined by 16S rRNA gene clone library analysis and further by applying a set of newly designed oligonucleotide probes targeting 16S rRNA gene sequences of α- or β-proteobacterial PHAAOs. The results demonstrated that the microbial community composition of PHAAOs differed in the class Alphaproteobacteria and Betaproteobacteria, which possibly resulted in a different PHA accumulation capacity among the WWTPs (8.5–38.2 mg-C g-VSS−1 h−1). The present study extended the knowledge of the microbial diversity of PHAAOs in full-scale WWTPs operated in fully aerobic mode. PMID:23257912

  16. Synchronized growth and neutral lipid accumulation in Chlorella sorokiniana FC6 IITG under continuous mode of operation.

    PubMed

    Kumar, Vikram; Muthuraj, Muthusivaramapandian; Palabhanvi, Basavaraj; Das, Debasish

    2016-01-01

    Synchronized growth and neutral lipid accumulation with high lipid productivity under mixotrophic growth of the strain Chlorella sorokiniana FC6 IITG was achieved via manipulation of substrates feeding mode and supplementation of lipid elicitors in the growth medium. Screening and optimization of lipid elicitors resulted in lipid productivity of 110.59mgL(-1)day(-1) under the combined effect of lipid inducers sodium acetate and sodium chloride. Fed-batch cultivation of the strain in bioreactor with intermittent feeding of limiting nutrients and lipid inducer resulted in maximum biomass and lipid productivity of 2.08 and 0.97gL(-1)day(-1) respectively. Further, continuous production of biomass with concomitant lipid accumulation was demonstrated via continuous feeding of BG11 media supplemented with lipid inducers sodium acetate and sodium chloride. The improved biomass and lipid productivity in chemostat was found to be 2.81 and 1.27gL(-1)day(-1) respectively operated at a dilution rate of 0.54day(-1). PMID:26575619

  17. A uniform doping ultra-thin SOI LDMOS with accumulation-mode extended gate and back-side etching technology

    NASA Astrophysics Data System (ADS)

    Yan-Hui, Zhang; Jie, Wei; Chao, Yin; Qiao, Tan; Jian-Ping, Liu; Peng-Cheng, Li; Xiao-Rong, Luo

    2016-02-01

    A uniform doping ultra-thin silicon-on-insulator (SOI) lateral-double-diffused metal-oxide-semiconductor (LDMOS) with low specific on-resistance (Ron,sp) and high breakdown voltage (BV) is proposed and its mechanism is investigated. The proposed LDMOS features an accumulation-mode extended gate (AG) and back-side etching (BE). The extended gate consists of a P- region and two diodes in series. In the on-state with VGD > 0, an electron accumulation layer is formed along the drift region surface under the AG. It provides an ultra-low resistance current path along the whole drift region surface and thus the novel device obtains a low temperature distribution. The Ron,sp is nearly independent of the doping concentration of the drift region. In the off-state, the AG not only modulates the surface electric field distribution and improves the BV, but also brings in a charge compensation effect to further reduce the Ron,sp. Moreover, the BE avoids vertical premature breakdown to obtain high BV and allows a uniform doping in the drift region, which avoids the variable lateral doping (VLD) and the “hot-spot” caused by the VLD. Compared with the VLD SOI LDMOS, the proposed device simultaneously reduces the Ron,sp by 70.2% and increases the BV from 776 V to 818 V. Project supported by the National Natural Science Foundation of China (Grant Nos. 61176069 and 61376079).

  18. The effect of an anisotropic pressure of thermal particles on resistive wall mode stability

    SciTech Connect

    Berkery, J. W. Sabbagh, S. A.; Betti, R.; Guazzotto, L.; Manickam, J.

    2014-11-15

    The effect of an anisotropic pressure of thermal particles on resistive wall mode stability in tokamak fusion plasmas is derived through kinetic theory and assessed through calculation with the MISK code [B. Hu et al., Phys. Plasmas 12, 0 57301 (2005)]. The fluid anisotropy is treated as a small perturbation on the plasma equilibrium and modeled with a bi-Maxwellian distribution function. A complete stability treatment without an assumption of high frequency mode rotation leads to anisotropic kinetic terms in the dispersion relation in addition to anisotropy corrections to the fluid terms. With the density and the average pressure kept constant, when thermal particles have a higher temperature perpendicular to the magnetic field than parallel, the fluid pressure-driven ballooning destabilization term is reduced. Additionally, the stabilizing kinetic effects of the trapped thermal ions can be enhanced. Together these two effects can lead to a modest increase in resistive wall mode stability.

  19. Commuter exposure to ultrafine particles in different urban locations, transportation modes and routes

    NASA Astrophysics Data System (ADS)

    Ragettli, Martina S.; Corradi, Elisabetta; Braun-Fahrländer, Charlotte; Schindler, Christian; de Nazelle, Audrey; Jerrett, Michael; Ducret-Stich, Regina E.; Künzli, Nino; Phuleria, Harish C.

    2013-10-01

    A better understanding of ultrafine particle (UFP) exposure in different urban transport microenvironments is important for epidemiological exposure assessments and for policy making. Three sub-studies were performed to characterize personal exposure to UFP concentration and average particle size distribution diameters in frequently traveled commuter microenvironments in the city of Basel, Switzerland. First, the spatial variation of sidewalk UFP exposures within urban areas and transport-specific microenvironments was explored. Second, exposure to UFP concentration and average particle size were quantified for five modes of transportation (walking, bicycle, bus, tram, car) during different times of the day and week, along the same route. Finally, the contribution of bicycle commuting along two different routes (along main roads, away from main roads) to total daily exposures was assessed by 24-h personal measurements. In general, smaller average particle sizes and higher UFP levels were measured at places and for travel modes in close proximity to traffic. Average trip UFP concentrations were higher in car (31,784 particles cm-³) and on bicycle (22,660 particles cm-³) compared to walking (19,481 particles cm-³) and public transportation (14,055-18,818 particles cm-³). Concentrations were highest for all travel modes during weekday morning rush hours, compared to other time periods. UFP concentration was lowest in bus, regardless of time period. Bicycle travel along main streets between home and work place (24 min on average) contributed 21% and 5% to total daily UFP exposure in winter and summer, respectively. Contribution of bicycle commutes to total daily UFP exposure could be reduced by half if main roads are avoided. Our results show the importance of considering commuter behavior and route choice in exposure assessment studies.

  20. Cancellation of drift kinetic effects between thermal and energetic particles on the resistive wall mode stabilization

    NASA Astrophysics Data System (ADS)

    Guo, S. C.; Liu, Y. Q.; Xu, X. Y.; Wang, Z. R.

    2016-07-01

    Drift kinetic stabilization of the resistive wall mode (RWM) is computationally investigated using MHD-kinetic hybrid code MARS-K following the non-perturbative approach (Liu et al 2008 Phys. Plasmas 15 112503), for both reversed field pinch (RFP) and tokamak plasmas. Toroidal precessional drift resonance effects from trapped energetic ions (EIs) and various kinetic resonances between the mode and the guiding center drift motions of thermal particles are included into the self-consistent toroidal computations. The results show cancellation effects of the drift kinetic damping on the RWM between the thermal particles and EIs contributions, in both RFP and tokamak plasmas, even though each species alone can provide damping and stabilize RWM instability by respective kinetic resonances. The degree of cancellation generally depends on the EIs equilibrium distribution, the particle birth energy, as well as the toroidal flow speed of the plasma.

  1. Tailoring nanostructured, graded, and particle-reinforced Al laminates by accumulative roll bonding.

    PubMed

    Göken, Mathias; Höppel, Heinz Werner

    2011-06-17

    Accumulative roll bonding (ARB) is a very attractive process for processing large sheets to achieve ultrafine-grained microstructure and high strength. Commercial purity Al and many Al alloys from the 5xxx and the precipitation strengthened 6xxx alloy series have been successfully processed by the ARB process into an ultrafine-grained state and superior ductility have been achieved for some materials like technical purity Al. It has also been shown that the ARB process can be successfully used to produce multi-component materials with tailored properties by reinforcement or grading, respectively. This allows optimizing the properties based on two or more materials/alloys. For example, to achieve high corrosion resistance and good visual surface properties it is interesting to produce a composite of two different Al alloys, where for example a high strength alloy of the 5xxx series is used as the core material and a 6xxx series alloy as the clad material. It has been shown that such a composite achieves more or less the same strength as the core material although 50% of the composite consists of the significant softer clad alloy. Furthermore, it has been found, that the serrated yielding which typically appears in 5xxx series alloys and limits applications as outer skin materials completely disappears. Moreover, the ARB process allows many other attractive ways to design new composites and graded material structures with unique properties by the introduction of particles, fibres and sheets. Strengthening with nanoparticles for example is a very attractive way to improve the properties and accelerate the grain refining used in the severe plastic deformation process. With an addition of only 0.1 vol.-% Al2O3 nanoparticles a significantly accelerated grain refinement has been found which reduces the number of ARB passes necessary to achieve the maximum in strength. The paper provides a short review on recent developments in the field of ARB processing for producing

  2. Evaluation of existence region and formation time of particle accumulation structure (PAS) in half-zone liquid bridge

    NASA Astrophysics Data System (ADS)

    Gotoda, M.; Sano, T.; Kaneko, T.; Ueno, I.

    2015-03-01

    We focused on the particle accumulation structure (PAS) produced by the thermocapillary effect in a half-zone liquid bridge. Although models of the formation of the PAS have been previously proposed, they have not been experimentally verified. An assessment of the region in which the PAS exists is very subjective and often dependent on the observer, and this has necessitated the development of an objective and quantitative evaluation method. We therefore conducted a series of experiments to verify the physical model of the particle path lines in a rotating frame of reference using the fundamental frequency of the hydrothermal wave. We evaluated the intensity of the particle accumulation based on a modification of the "accumulation measure" proposed by Kuhlmann and Muldoon (Phys. Rev. E, 2012) to objectively and quantitatively determine the existence region of the SL-1 PAS. The results of the quantitative experiment revealed that the best aspect ratio (ratio of the height to radius) of the liquid bridge for the SL-1 PAS was about 0.64, and that the PAS formation time was nearly the same as the thermal diffusion time under the considered conditions (184 words, within 200 words).

  3. Convective particle transport arising from poloidal inhomogeneity in tokamak H mode

    SciTech Connect

    Kasuya, N.; Itoh, K.

    2005-09-15

    In tokamak high-confinement modes (H modes), a large poloidal flow exists within an edge transport barrier, and the electrostatic potential and density profiles can be steep both in the radial and poloidal directions. The two-dimensional structures of the electrostatic potential, density, and flow velocity near the edge of a tokamak plasma are investigated. The analysis is carried out with the momentum conservation law using the shock ordering. For the case with a strong radial electric field (H-mode case), a particle flux is induced from asymmetry of the poloidal electric field in the transport barrier. This convective transport is found to depend weakly on collisionality, and changes its direction in accordance with the direction of the radial electric field, the toroidal magnetic field, and the plasma current. The divergence of a particle flux is a source of temporal variation of the density, and there are negative divergence regions both in the inward and outward flux cases. Thus this convective particle flux is a new candidate for the cause of the rapid establishment of the density pedestal after the onset of low to high confinement mode (L/H) transition.

  4. Gyrokinetic simulation studies on the energetic-particle-induced geodesic acoustic mode

    NASA Astrophysics Data System (ADS)

    Miki, Kazuhiro; Idomura, Yasuhiro

    2014-10-01

    Understanding of the energetic particles physics is of great interest in the future burning plasmas. Particularly, particle loss in the presence of EGAM may be critical for ITER. We thus need to know how EGAM is excited and interacts with turbulence. We here introduce energetic particles in a full-f gyrokinetic code (GT5D). (i) We find linear dynamics of the EGAM driven by bump-on-tail particle distributions. We examine flat-q, homogeneous, axisymmetric, electrostatic gyrokinetic simulations. Above a certain level of the beam intensity, an oscillatory mode grows with about a half of the standard GAM. The observed frequencies are consistent with the eigenmode analyses derived from the perturbed gyrokinetic equations. The theoretical analyses also indicate a bifurcation of the excited modes depending on q-value. Estimation of the finite-orbit-width effects can provide a size dependency of the EGAM growth rate. (ii) We find linear and nonlinear dynamics of the EGAM driven by slowing-down distributions. We examine the axisymmetric gyrokinetic simulations with DIII-D-like parameters. The observed growth rates and frequencies are consistent with results of other hybrid code. Furthermore, we will focus on nonlinear phase space dynamics, namely chirping mode. This work is supported by HPCI Strategic Program Field No.4: Next-Generation Industrial Innovations, funded by the MEXT, Japan.

  5. Hybrid simulation of energetic particle effects on tearing modes in tokamak plasmas

    SciTech Connect

    Cai Huishan; Fu Guoyong

    2012-07-15

    The effects of energetic ions on stability of tearing mode are investigated by global kinetic/MHD hybrid simulations in a low beta tokamak plasma. The kinetic effects of counter circulating energetic ions from the non-adiabatic response are found to be strongly destabilizing while the effects from the adiabatic response are stabilizing. The net effect with both adiabatic and non-adiabatic contributions is destabilizing. On the other hand, the kinetic effects of co-circulating energetic ions from the non-adiabatic response are calculated to be weakly stabilizing while the corresponding adiabatic contribution is destabilizing for small energetic ion beta. The net effect is weakly stabilizing. The dependence of kinetic effects on energetic ion beta, gyroradius, and speed is studied systematically and the results agree in large part with the previous analytic results for the kinetic effects of circulating particles. For trapped energetic ions, their effects on tearing mode stability are dominated by the adiabatic response due to large banana orbit width and strong poloidal variation of particle pressure. The net effect of trapped energetic particles on tearing modes is much more destabilizing as compared to that of counter circulating particles at the same beta value.

  6. Physical Investigations of Small Particles: (I) Aerosol Particle Charging and Flux Enhancement and (II) Whispering Gallery Mode Sensing

    NASA Astrophysics Data System (ADS)

    Lopez-Yglesias, Xerxes

    of the molecule and the electromagnetic interaction between the molecule and particle, especially for the neutral particle case, are completely ignored, or, as is often the case for a permanent dipole vapor species, strongly underestimated. Comparing our model to these classical models we determine an "enhancement factor" to characterize how important the addition of these physical parameters and processes is to the understanding of particle nucleation and growth. Part II: Whispering gallery mode (WGM) optical biosensors are capable of extraordinarily sensitive specific and non-specific detection of species suspended in a gas or fluid. Recent experimental results suggest that these devices may attain single-molecule sensitivity to protein solutions in the form of stepwise shifts in their resonance wavelength, lambdaR, but present sensor models predict much smaller steps than were reported. This study examines the physical interaction between a WGM sensor and a molecule adsorbed to its surface, exploring assumptions made in previous efforts to model WGM sensor behavior, and describing computational schemes that model the experiments for which single protein sensitivity was reported. The resulting model is used to simulate sensor performance, within constraints imposed by the limited material property data. On this basis, we conclude that nonlinear optical effects would be needed to attain the reported sensitivity, and that, in the experiments for which extreme sensitivity was reported, a bound protein experiences optical energy fluxes too high for such effects to be ignored.

  7. Stability of particle propulsion by waveguide modes in the regimes where resonant states are formed

    NASA Astrophysics Data System (ADS)

    Maslov, A. V.

    2015-09-01

    Optical forces acting on dielectric particles inside waveguides are studied. The investigation is carried out within the framework of the two-dimensional model: a cylinder inside a parallel-plate waveguide with perfect metal walls. It is shown that although the appearance of resonant states can lead to a significant increase of backscattering and, therefore, the propelling force, the transverse force can either keep the particle in the location of the efficient propulsion or push it away. The propulsion and trapping regimes are related to the change of the resonant wavelength with particle location. Besides the geometrical and material parameters, the polarization of the incident mode is shown to significantly affect the particle dynamics. The relation of the resonant-state formation and Wood's anomalies in periodic gratings is also discussed.

  8. Global Hybrid Simulations of Energetic Particle Effects on the n=1 Mode in Tokamaks: Internal Kink and Fishbone Instability

    SciTech Connect

    G.Y. Fu; W. Park; H.R. Strauss; J. Breslau; J. Chen; S. Jardin; L.E. Sugiyama

    2005-08-09

    Global hybrid simulations of energetic particle effects on the n=1 internal kink mode have been carried out for tokamaks. For the International Thermonuclear Experimental Reactor (ITER) [ITER Physics Basis Editors et al., Nucl. Fusion 39:2137 (1999)], it is shown that alpha particle effects are stabilizing for the internal kink mode. However, the elongation of ITER reduces the stabilization effects significantly. Nonlinear simulations of the precessional drift fishbone instability for circular tokamak plasmas show that the mode saturates due to flattening of the particle distribution function near the resonance region. The mode frequency chirps down rapidly as the flattening region expands radially outward. Fluid nonlinearity reduces the saturation level.

  9. Meteoric Dust as Condensation Nuclei of Small-Mode Particles in the Upper Haze of Venus

    NASA Astrophysics Data System (ADS)

    Gao, P.; Zhang, X.; Crisp, D.; Bardeen, C.; Yung, Y. L.

    2012-12-01

    Observations by the SPICAV/SOIR instruments aboard Venus Express have revealed that the Upper Haze of Venus is populated by two particle modes, as reported by Wilquet et al. (J. Geophys. Res., 114, E00B42, 2009). In this work, we posit that the large mode is made up of cloud particles that have diffused upwards from the cloud deck below, while the smaller mode is generated by the in situ nucleation of meteoric dust. We test this hypothesis by using version 3.0 of the Community Aerosol and Radiation Model for Atmospheres, first developed by Turco et al. (J. Atmos. Sci., 36, 699-717, 1979) and upgraded to version 3.0 by Bardeen et al. (The CARMA 3.0 microphysics package in CESM, Whole Atmosphere Working Group Meeting, 2011). Using the meteoric dust production profile of Kalashnikova et al. (Geophys. Res. Lett., 27, 3293-3296, 2000), the sulfur/sulfate condensation nuclei production profile of Imamura and Hashimoto (J. Atmos. Sci., 58, 3597-3612, 2001), and sulfuric acid vapor production profile of Zhang et al. (Icarus, 217, 714-739, 2012), we numerically simulate a column of the Venus atmosphere from 40 to 100 km above the surface. Our aerosol number density results agree well with Pioneer Venus data from Knollenberg and Hunten (J. Geophys. Res., 85, 8039-8058, 1980), while our gas distribution results match that of Kolodner and Steffes below 55 km (Icarus, 132, 151-169, 1998). The resulting size distribution of cloud particles shows two distinct modes, qualitatively matching the observations of Pioneer Venus. We also observe a third mode in our results with a size of a few microns at 48 km altitude, which appears to support the existence of the controversial third mode in the Pioneer Venus data. This mode disappears if coagulation is not included in the simulation. The Upper Haze size distribution shows two lognormal-like distributions overlapping each other, possibly indicating the presence of the two distinct modes. We test our hypothesis by simulating the

  10. Localized accumulation and a shelf-basin gradient of particles in the Chukchi Sea and Canada Basin, western Arctic

    NASA Astrophysics Data System (ADS)

    Yamada, Yosuke; Fukuda, Hideki; Uchimiya, Mario; Motegi, Chiaki; Nishino, Shigeto; Kikuchi, Takashi; Nagata, Toshi

    2015-07-01

    Transparent exopolymer particles (TEP), particulate organic carbon (POC), and particles (size range: 5.2-119 μm) as determined by laser in situ scattering and transmissometry (LISST) were measured in the water column from the Chukchi Sea to the Canada Basin in the western Arctic Ocean, during the late summer of 2012. In general, the percentages of TEP-carbon to POC were high (the mean values for the shelf and slope-basin regions were 135.4 ± 58.0% (± standard deviation, n = 36) and 187.6 ± 73.3% (n = 58), respectively), relative to the corresponding values reported for other oceanic regions, suggesting that TEP play an important role in regulating particle dynamics. A hotspot (extremely high concentration) of particles, accompanied by high prokaryote abundance and production, was observed near the seafloor (depth 50 m) of the shelf region. Localized accumulation of particles was also found in the thin layer near the pycnocline (depth 10-30 m) and on the slope. Over a broader spatial scale, particle concentration gradients were identified from the shelf to the basin in the upper water column (<50 m). The particle-size distribution analysis indicated that relatively small particles were dominant in the shelf region compared to the slope-basin region. These results suggest that particles containing large amounts of TEP are produced in the shelf region and are potentially delivered to the slope-basin region along the pycnocline, which might support productivity and material cycles in the nutrient-depleted basin region of the western Arctic Ocean.

  11. ELM triggering by energetic particle driven mode in wall-stabilized high-β plasmas

    NASA Astrophysics Data System (ADS)

    Matsunaga, G.; Aiba, N.; Shinohara, K.; Asakura, N.; Isayama, A.; Oyama, N.; the JT-60 Team

    2013-07-01

    In the JT-60U high-β plasmas above the no-wall β limit, a triggering of an edge localized mode (ELM) by an energetic particle (EP)-driven mode has been observed. This EP-driven mode is thought to be driven by trapped EPs and it has been named EP-driven wall mode (EWM) on JT-60U (Matsunaga et al 2009 Phys. Rev. Lett. 103 045001). When the EWM appears in an ELMy H-mode phase, ELM crashes are reproducibly synchronized with the EWM bursts. The EWM-triggered ELM has a higher repetition frequency and less energy loss than those of the natural ELM. In order to trigger an ELM by the EP-driven mode, some conditions are thought to be needed, thus an EWM with large amplitude and growth rate, and marginal edge stability. In the scrape-off layer region, several measurements indicate an ion loss induced by the EWM. The ion transport is considered as the EP transport through the edge region. From these observations, the EP contributions to edge stability are discussed as one of the ELM triggering mechanisms.

  12. ACCUMULATION AND TISSUE DISPOSITION OF PARTICLE ASSOCIATED ELEMENTS IN THE RAT AFTER REPEATED INTRATRACHAEL ADMINISTRATION OF SOURCE PARTICLES

    EPA Science Inventory

    The goal of this study was to determine the fate of source particle tracer elements following repeated intratracheal instillation (IT) to rats. PM samples comprised Mt. St. Helens ash (MSH) with no water-soluble metals, and oil flyash emission PM (EPM) with water-leachable solubl...

  13. Influence of mileage accumulation on the particle mass and number emissions of two gasoline direct injection vehicles.

    PubMed

    Maricq, M Matti; Szente, Joseph J; Adams, Jack; Tennison, Paul; Rumpsa, Todd

    2013-10-15

    Gasoline direct injection (GDI) is a new engine technology intended to improve fuel economy and greenhouse gas emissions as required by recently enacted legislative and environmental regulations. The development of this technology must also ensure that these vehicles meet new LEV III and Tier 3 emissions standards as they phase in between 2017 and 2021. The aim of the present paper is to examine, at least for a small set, how the PM emissions from GDI vehicles change over their lifetime. The paper reports particle mass and number emissions of two GDI vehicles as a function of mileage up to 150K miles. These vehicles exhibit PM emissions that are near or below the upcoming 3 mg/mi FTP and 10 mg/mi US06 mass standards with little, if any, deterioration over 150K miles. Particle number emissions roughly follow the previously observed 2 × 10(12) particles/mg correlation between solid particle number and PM mass. They remained between the interim and final EU stage 6 solid particle count standard for gasoline vehicles throughout the mileage accumulation study. These examples demonstrate feasibility to meet near-term 3 mg/mi and interim EU solid particle number standards, but continued development is needed to ensure that this continues as further fuel economy improvements are made. PMID:24040936

  14. Rapid Frequency Chirps of TAE mode due to Finite Orbit Energetic Particles

    NASA Astrophysics Data System (ADS)

    Berk, Herb; Wang, Ge

    2013-10-01

    The tip model for the TAE mode in the large aspect ratio limit, conceived by Rosenbluth et al. in the frequency domain, together with an interaction term in the frequency domain based on a map model, has been extended into the time domain. We present the formal basis for the model, starting with the Lagrangian for the particle wave interaction. We shall discuss the formal nonlinear time domain problem and the procedure that needs to obtain solutions in the adiabatic limit.

  15. High variability of stress accumulation, seismic and aseismic release mode along the Peru-Ecuador subduction zone (Invited)

    NASA Astrophysics Data System (ADS)

    Nocquet, J.; Villegas, J. C.; Chlieh, M.; Mothes, P. A.; Rolandone, F.; Jarrín, P.; Cisneros, D.; Vallee, M.

    2013-12-01

    Most geodetic measurements of interseismic strain along subduction zones have led to the view of coupled asperities of variable size usually separated by narrower zones of low coupling. Along the western margin of South America, fast convergence of the oceanic Nazca plate has repeatedly produced M>8 earthquakes and three of the ten largest megathrust earthquakes since 1900. Contrasting with this behavior, the segment comprised between central Peru and central Ecuador has not experienced any great earthquake for at least five centuries. New GPS measurements in Peru and Ecuador first highlight that a along a ~1000km long segment, convergence is predominantly accommodated by aseismic creep along the plate interface, with possible coupling occurring at shallow depth, close to the trench. This area is bounded by highly locked segments, which produced M>8.5 earthquakes in central Peru and northern Ecuador. While the observed low interseismic coupling explains the lack of great earthquakes, this area has experienced two earthquakes that share the characteristics of tsunamigenic earthquakes, indicating a correlation between the mode of stress accumulation along the plate interface and its release. Finally, we have observed several episodes of slow slip, sometimes associated with intense, micro to moderate seismicity. These observations suggest a specific behavior for this segment, which contrasts with the behavior of the neighboring segments.

  16. Particle simulation on radio frequency stabilization of flute modes in a tandem mirror. I. Parallel antenna

    SciTech Connect

    Kadoya, Y.; Abe, H.

    1988-04-01

    A two- and one-half-dimensional electromagnetic particle code (PS2M) (H. Abe and S. Nakajima, J. Phys. Soc. Jpn. 53, xxx (1987)) is used to study how an electric field applied parallel to the magnetic field affects the radio frequency stabilization of flute modes in a tandem mirror plasma. The parallel electric field E/sub parallel/ perturbs the electron velocity v/sub parallel/ parallel to the magnetic field and also induces a perpendicular magnetic field perturbation B/sub perpendicular/. The unstable growth of the flute mode in the absence of such a radio frequency electric field is first studied as a basis for comparison. The ponderomotive force originating from the time-averaged product is then shown to stabilize the flute modes. The stabilizing wave power threshold, the frequency dependency, and the dependence on delchemically bondE/sub parallel/chemically bond all agree with the theoretical predictions.

  17. Observation of Energetic Particle Driven Modes Relevant to Advanced Tokamak Regimes

    SciTech Connect

    R. Nazikian; B. Alper; H.L. Berk; D. Borba; C. Boswell; R.V. Budny; K.H. Burrell; C.Z. Cheng; E.J. Doyle; E. Edlund; R.J. Fonck; A. Fukuyama; N.N. Gorelenkov; C.M. Greenfield; D.J. Gupta; M. Ishikawa; R.J. Jayakumar; G.J. Kramer; Y. Kusama; R.J. La Haye; G.R. McKee; W.A. Peebles; S.D. Pinches; M. Porkolab; J. Rapp; T.L. Rhodes; S.E. Sharapov; K. Shinohara; J.A. Snipes; W.M. Solomon; E.J. Strait; M. Takechi; M.A. Van Zeeland; W.P. West; K.L. Wong; S. Wukitch; L. Zeng

    2004-10-21

    Measurements of high-frequency oscillations in JET [Joint European Torus], JT-60U, Alcator C-Mod, DIII-D, and TFTR [Tokamak Fusion Test Reactor] plasmas are contributing to a new understanding of fast ion-driven instabilities relevant to Advanced Tokamak (AT) regimes. A model based on the transition from a cylindrical-like frequency-chirping mode to the Toroidal Alfven Eigenmode (TAE) has successfully encompassed many of the characteristics seen in experiments. In a surprising development, the use of internal density fluctuation diagnostics has revealed many more modes than has been detected on edge magnetic probes. A corollary discovery is the observation of modes excited by fast particles traveling well below the Alfven velocity. These observations open up new opportunities for investigating a ''sea of Alfven Eigenmodes'' in present-scale experiments, and highlight the need for core fluctuation and fast ion measurements in a future burning-plasma experiment.

  18. Single-particle imaging reveals intraflagellar transport–independent transport and accumulation of EB1 in Chlamydomonas flagella

    PubMed Central

    Harris, J. Aaron; Liu, Yi; Yang, Pinfen; Kner, Peter; Lechtreck, Karl F.

    2016-01-01

    The microtubule (MT) plus-end tracking protein EB1 is present at the tips of cilia and flagella; end-binding protein 1 (EB1) remains at the tip during flagellar shortening and in the absence of intraflagellar transport (IFT), the predominant protein transport system in flagella. To investigate how EB1 accumulates at the flagellar tip, we used in vivo imaging of fluorescent protein–tagged EB1 (EB1-FP) in Chlamydomonas reinhardtii. After photobleaching, the EB1 signal at the flagellar tip recovered within minutes, indicating an exchange with unbleached EB1 entering the flagella from the cell body. EB1 moved independent of IFT trains, and EB1-FP recovery did not require the IFT pathway. Single-particle imaging showed that EB1-FP is highly mobile along the flagellar shaft and displays a markedly reduced mobility near the flagellar tip. Individual EB1-FP particles dwelled for several seconds near the flagellar tip, suggesting the presence of stable EB1 binding sites. In simulations, the two distinct phases of EB1 mobility are sufficient to explain its accumulation at the tip. We propose that proteins uniformly distributed throughout the cytoplasm like EB1 accumulate locally by diffusion and capture; IFT, in contrast, might be required to transport proteins against cellular concentration gradients into or out of cilia. PMID:26631555

  19. Single-particle imaging reveals intraflagellar transport-independent transport and accumulation of EB1 in Chlamydomonas flagella.

    PubMed

    Harris, J Aaron; Liu, Yi; Yang, Pinfen; Kner, Peter; Lechtreck, Karl F

    2016-01-15

    The microtubule (MT) plus-end tracking protein EB1 is present at the tips of cilia and flagella; end-binding protein 1 (EB1) remains at the tip during flagellar shortening and in the absence of intraflagellar transport (IFT), the predominant protein transport system in flagella. To investigate how EB1 accumulates at the flagellar tip, we used in vivo imaging of fluorescent protein-tagged EB1 (EB1-FP) in Chlamydomonas reinhardtii. After photobleaching, the EB1 signal at the flagellar tip recovered within minutes, indicating an exchange with unbleached EB1 entering the flagella from the cell body. EB1 moved independent of IFT trains, and EB1-FP recovery did not require the IFT pathway. Single-particle imaging showed that EB1-FP is highly mobile along the flagellar shaft and displays a markedly reduced mobility near the flagellar tip. Individual EB1-FP particles dwelled for several seconds near the flagellar tip, suggesting the presence of stable EB1 binding sites. In simulations, the two distinct phases of EB1 mobility are sufficient to explain its accumulation at the tip. We propose that proteins uniformly distributed throughout the cytoplasm like EB1 accumulate locally by diffusion and capture; IFT, in contrast, might be required to transport proteins against cellular concentration gradients into or out of cilia. PMID:26631555

  20. Growth of nucleation mode particles in the summertime Arctic: a case study

    NASA Astrophysics Data System (ADS)

    Willis, Megan D.; Burkart, Julia; Thomas, Jennie L.; Köllner, Franziska; Schneider, Johannes; Bozem, Heiko; Hoor, Peter M.; Aliabadi, Amir A.; Schulz, Hannes; Herber, Andreas B.; Leaitch, W. Richard; Abbatt, Jonathan P. D.

    2016-06-01

    The summertime Arctic lower troposphere is a relatively pristine background aerosol environment dominated by nucleation and Aitken mode particles. Understanding the mechanisms that control the formation and growth of aerosol is crucial for our ability to predict cloud properties and therefore radiative balance and climate. We present an analysis of an aerosol growth event observed in the Canadian Arctic Archipelago during summer as part of the NETCARE project. Under stable and clean atmospheric conditions, with low inversion heights, carbon monoxide less than 80 ppbv, and black carbon less than 5 ng m-3, we observe growth of small particles, < 20 nm in diameter, into sizes above 50 nm. Aerosol growth was correlated with the presence of organic species, trimethylamine, and methanesulfonic acid (MSA) in particles ˜ 80 nm and larger, where the organics are similar to those previously observed in marine settings. MSA-to-sulfate ratios as high as 0.15 were observed during aerosol growth, suggesting an important marine influence. The organic-rich aerosol contributes significantly to particles active as cloud condensation nuclei (CCN, supersaturation = 0.6 %), which are elevated in concentration during aerosol growth above background levels of ˜ 100 to ˜ 220 cm-3. Results from this case study highlight the potential importance of secondary organic aerosol formation and its role in growing nucleation mode aerosol into CCN-active sizes in this remote marine environment.

  1. Comparison of sulfur measurements from a regional fine particle network with concurrent acid modes network results

    SciTech Connect

    Bennett, R.L.; Stockburger, L.; Barnes, H.M.

    1994-01-01

    The Fine Particle Network (FPN), a system of fine particle (less than 2.5 micrometers) samplers, was operated at 41 sites selected from the Enviromental Protection Agency Acid MODES program during the two year period in 1988-90. The 24-hour sample results included fine particle mass and the most predominant chemical element concentrations determined by wavelength dispersive x-ray fluorescence analysis. Statistical summaries of the fine mass and sulfur concentrations by site and season were prepared. The availability of simultaneous particulate sulfate measurements from independent collection and analytical procedures provided an opportunity to examine their agreement and provide a more reliable data base for evaluation of regional particulate models and estimation of contribution to urban aerosol concentration.

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

    SciTech Connect

    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.

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

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    Wang, Xian-Qu; Zhang, Rui-Bin; Meng, Guo

    2016-07-01

    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.

  5. Particle in cell simulations of tearing modes in reversed-field-pinch-like plasma

    SciTech Connect

    Svidzinski, Vladmir; Li, Hui; Albright, Brian

    2008-01-01

    Particle in cell (PIC) simulations of tearing modes in two-dimensional plane geometry in a force free reversed field pinch (RFP) like plasma equilibrium are performed to study possible kinetic effects on these modes in RFPs. Linear tearing modes are compared in the PIC and two fluid models. The results showed that the growth rates and the profiles of magnetic field components in the two models are very similar, indicating that the kinetic effects on the tearing modes are weak such that the two fluid approximation is rather accurate for modeling these instabilities in RFPs. During the nonlinear evolution of the tearing mode in this geometry small scale secondary instabilities located near the internal layer of the primary tearing instability are excited. These secondary instabilities appear to be driven by the nonlinearly induced local pressure gradient in the regions of unfavorable curvature of the nonlinearly evolved magnetic field. They could also appear in a realistic RFP geometry and play a role during sawtooth crashes in these machines.

  6. First observation of alpha particle loss induced by kinetic ballooning modes in TFTR deuterium-tritium experiments

    SciTech Connect

    Chang, Z.; Budny, R.V.; Chen, L.; Darrow, D.; Fredrickson, E.D.; Janos, A.; Mansfield, D.; Mazzucato, E.; McGuire, K.M.; Nazikian, R.; Rewoldt, G.; Strachan, J.D.; Tang, W.M.; Taylor, G.; White, R.B.; Zweben, S. |; TFTR group

    1996-02-01

    A correlation between the measured alpha particle loss and high frequency ({approximately}100{endash}200 kHz) magnetohydrodynamic (MHD) modes has been observed in some high {beta} (= plasma pressure/magnetic pressure) DT plasmas in TFTR. These modes are localized around the peak plasma pressure gradient and have ballooning characteristics. Particle simulation shows that the loss is due to wave-particle resonances. Linear instability analysis indicates that the plasma is unstable to the kinetic MHD ballooning modes driven by strong local pressure gradients. {copyright} {ital 1996 The American Physical Society.}

  7. Distribution of the concentration of heavy metals associated with the sediment particles accumulated on road surfaces.

    PubMed

    Zafra, C A; Temprano, J; Tejero, I

    2011-07-01

    The heavy metal pollution caused by road run-off water constitutes a problem in urban areas. The metallic load associated with road sediment must be determined in order to study its impact in drainage systems and receiving waters, and to perfect the design of prevention systems. This paper presents data regarding the sediment collected on road surfaces in the city of Torrelavega (northern Spain) during a period of 65 days (132 samples). Two sample types were collected: vacuum-dried samples and those swept up following vacuuming. The sediment loading (g m(-2)), particle size distribution (63-2800 microm) and heavy metal concentrations were determined. The data showed that the concentration of heavy metals tends to increase with the reduction in the particle diameter (exponential tendency). The concentrations ofPb, Zn, Cu, Cr, Ni, Cd, Fe, Mn and Co in the size fraction <63 microm were 350, 630, 124, 57, 56, 38, 3231, 374 and 51 mg kg(-1), respectively (average traffic density: 3800 vehicles day(-1)). By increasing the residence time of the sediment, the concentration increases, whereas the ratio of the concentration between the different size fractions decreases. The concentration across the road diminishes when the distance between the roadway and the sampling siteincreases; when the distance increases, the ratio between size fractions for heavy metal concentrations increases. Finally, the main sources of heavy metals are the particles detached by braking (brake pads) and tyre wear (rubber), and are associated with particle sizes <125 microm. PMID:21882553

  8. Particle velocity gradient based acoustic mode beamforming for short linear vector sensor arrays.

    PubMed

    Gur, Berke

    2014-06-01

    In this paper, a subtractive beamforming algorithm for short linear arrays of two-dimensional particle velocity sensors is described. The proposed method extracts the highly directional acoustic modes from the spatial gradients of the particle velocity field measured at closely spaced sensors along the array. The number of sensors in the array limits the highest order of modes that can be extracted. Theoretical analysis and numerical simulations indicate that the acoustic mode beamformer achieves directivity comparable to the maximum directivity that can be obtained with differential microphone arrays of equivalent aperture. When compared to conventional delay-and-sum beamformers for pressure sensor arrays, the proposed method achieves comparable directivity with 70%-85% shorter apertures. Moreover, the proposed method has additional capabilities such as high front-back (port-starboard) discrimination, frequency and steer direction independent response, and robustness to correlated ambient noise. Small inter-sensor spacing that results in very compact apertures makes the proposed beamformer suitable for space constrained applications such as hearing aids and short towed arrays for autonomous underwater platforms. PMID:24907810

  9. Collisionless microinstabilities in stellarators. I. Analytical theory of trapped-particle modes

    SciTech Connect

    Helander, P.; Proll, J. H. E.; Plunk, G. G.; Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald

    2013-12-15

    This is the first in a series of papers about collisionless, electrostatic micro-instabilities in stellarators, with an emphasis on trapped-particle modes. It is found that, in so-called maximum-J configurations, trapped-particle instabilities are absent in large regions of parameter space. Quasi-isodynamic stellarators have this property (approximately), and the theory predicts that trapped electrons are stabilizing to all eigenmodes with frequencies below the electron bounce frequency. The physical reason is that the bounce-averaged curvature is favorable for all orbits, and that trapped electrons precess in the direction opposite to that in which drift waves propagate, thus precluding wave-particle resonance. These considerations only depend on the electrostatic energy balance and are independent of all geometric properties of the magnetic field other than the maximum-J condition. However, if the aspect ratio is large and the instability phase velocity differs greatly from the electron and ion thermal speeds, it is possible to derive a variational form for the frequency showing that stability prevails in a yet larger part of parameter space than what follows from the energy argument. Collisionless trapped-electron modes should therefore be more stable in quasi-isodynamic stellarators than in tokamaks.

  10. Anaerobic granule-based biofilms formation reduces propionate accumulation under high H2 partial pressure using conductive carbon felt particles.

    PubMed

    Xu, Heng; Wang, Cuiping; Yan, Kun; Wu, Jing; Zuo, Jiane; Wang, Kaijun

    2016-09-01

    Syngas based co-digestion is not only more economically attractive than separate syngas methanation but also able to upgrade biogas and increase overall CH4 amount simultaneously. However, high H2 concentration in the syngas could inhibit syntrophic degradation of propionate, resulting in propionate accumulation and even failure of the co-digestion system. In an attempt to reduce propionate accumulation via enhancing both H2 interspecies transfer (HIT) and direct interspecies electron transfer (DIET) pathways, layered granule-based biofilms induced by conductive carbon felt particles (CCFP) was employed. The results showed that propionate accumulation was effectively reduced with influent COD load up to 7gL(-1)d(-1). Two types of granule-based biofilms, namely biofilm adhered to CCFP (B-CCFP) and granules formed by self-immobilization (B-SI) were formed in the reactor. Clostridium, Syntrophobacter, Methanospirillum were possibly involved in HIT and Clostridium, Geobacter, Anaerolineaceae, Methanosaeta in DIET, both of which might be responsible for the high-rate propionate degradation. PMID:27289059

  11. Particle optics of quadrupole doublet magnets in Spallation Neutron Source accumulator ring

    NASA Astrophysics Data System (ADS)

    Wang, J. G.

    2006-12-01

    The Spallation Neutron Source ring employs doublet quadrupoles and dipole correctors in its straight sections. The electromagnetic quadrupoles have a large aperture, small aspect ratio, and relatively short iron-to-iron distance. The corrector is even closer to one of the quads. There have been concerns on the magnetic fringe field and interference in the doublet magnets and their assemblies. We have performed 3D computing simulations to study magnetic field distributions in the doublet magnets. Further, we have analyzed the particle optics based on the z-dependent focusing functions of the quads. The effect of the magnetic fringe field and interference, including the third-order aberrations, on the particle motion are investigated. The lens parameters and the first-order hard edge models are derived and compared with the parameters used in the ring lattice calculations.

  12. Functionalization of small platinum nanoparticles with amines and phosphines: Ligand binding modes and particle stability.

    PubMed

    Wand, Patricia; Bartl, Johannes D; Heiz, Ueli; Tschurl, Martin; Cokoja, Mirza

    2016-09-15

    We report the binding mode of amines and phosphines on platinum nanoparticles. Protective ligands comprising different functional groups are systematically studied for the elucidation of ligand binding at different functionalization conditions. From the functionalization conditions it is concluded that the binding of amines to the nanoparticles occurs via the formation of a PtHN moiety or electrostatic interaction, which is supported by spectroscopic evidences. In particular from complex chemistry such a binding mode is surprising, as amines are expected to bind via their electron pair to the metal. Similar results from functionalization are observed for phosphine-protected nanoparticles, which suggest similar binding modes in these systems. In contrast to the strong covalent bond of the protection with thiols, considerable weakly binding systems result. The characteristics of the binding mode are reflected by the stability of the colloids and their catalytic properties. In the selective hydrogenation of 3-hexyne to 3-hexene thiolate-stabilized Pt particles are highly stable, but exhibit the lowest activity. On the other hand, amine- and phosphine-capped platinum nanoparticles show a significantly higher activity, but rapidly agglomerate. PMID:27288572

  13. Nonlinear evolution of two fast-particle-driven modes near the linear stability threshold

    NASA Astrophysics Data System (ADS)

    Zaleśny, Jarosław; Galant, Grzegorz; Lisak, Mietek; Marczyński, Sławomir; Berczyński, Paweł; Gałkowski, Andrzej; Berczyński, Stefan

    2011-06-01

    A system of two coupled integro-differential equations is derived and solved for the non-linear evolution of two waves excited by the resonant interaction with fast ions just above the linear instability threshold. The effects of a resonant particle source and classical relaxation processes represented by the Krook, diffusion, and dynamical friction collision operators are included in the model, which exhibits different nonlinear evolution regimes, mainly depending on the type of relaxation process that restores the unstable distribution function of fast ions. When the Krook collisions or diffusion dominate, the wave amplitude evolution is characterized by modulation and saturation. However, when the dynamical friction dominates, the wave amplitude is in the explosive regime. In addition, it is found that the finite separation in the phase velocities of the two modes weakens the interaction strength between the modes.

  14. Two-dimensional structure and particle pinch in tokamak H mode.

    PubMed

    Kasuya, Naohiro; Itoh, Kimitaka

    2005-05-20

    Two-dimensional structures of the electrostatic potential, density, and flow velocity near the edge of a tokamak plasma are investigated. The model includes the nonlinearity in bulk-ion viscosity and turbulence-driven shear viscosity. For the case with the strong radial electric field (H mode), a two-dimensional structure in a transport barrier is obtained, giving a poloidal shock with a solitary radial electric field profile. The inward particle pinch is induced from this poloidal asymmetric electric field, and increases as the radial electric field becomes stronger. The abrupt increase of this inward ion and electron flux at the onset of L- to H-mode transition explains the rapid establishment of the density pedestal, which is responsible for the observed spontaneous self-reorganization into an improved confinement regime. PMID:16090180

  15. Two-Dimensional Structure and Particle Pinch in Tokamak H Mode

    SciTech Connect

    Kasuya, Naohiro; Itoh, Kimitaka

    2005-05-20

    Two-dimensional structures of the electrostatic potential, density, and flow velocity near the edge of a tokamak plasma are investigated. The model includes the nonlinearity in bulk-ion viscosity and turbulence-driven shear viscosity. For the case with the strong radial electric field (H mode), a two-dimensional structure in a transport barrier is obtained, giving a poloidal shock with a solitary radial electric field profile. The inward particle pinch is induced from this poloidal asymmetric electric field, and increases as the radial electric field becomes stronger. The abrupt increase of this inward ion and electron flux at the onset of L- to H-mode transition explains the rapid establishment of the density pedestal, which is responsible for the observed spontaneous self-reorganization into an improved confinement regime.

  16. Particle-size dependent accumulation and trophic transfer of cerium oxide through a terrestrial food chain.

    PubMed

    Hawthorne, Joseph; De la Torre Roche, Roberto; Xing, Baoshan; Newman, Lee A; Ma, Xingmao; Majumdar, Sanghamitra; Gardea-Torresdey, Jorge; White, Jason C

    2014-11-18

    The accumulation and trophic transfer of nanoparticle (NP) or bulk CeO2 through a terrestrial food chain was evaluated. Zucchini (Cucurbita pepo L.) was planted in soil with 0 or 1228 μg/g bulk or NP CeO2. After 28 d, zucchini tissue Ce content was determined by ICP-MS. Leaf tissue from each treatment was used to feed crickets (Acheta domesticus). After 14 d, crickets were analyzed for Ce content or were fed to wolf spiders (family Lycosidae). NP CeO2 significantly suppressed flower mass relative to control and bulk treatments. The Ce content of zucchini was significantly greater when exposure was in the NP form. The flowers, leaves, stems, and roots of zucchini exposed to bulk CeO2 contained 93.3, 707, 331, and 119,000 ng/g, respectively; NP-exposed plants contained 153, 1510, 479, and 567 000 ng/g, respectively. Crickets fed NP CeO2-exposed zucchini leaves contained significantly more Ce (33.6 ng/g) than did control or bulk-exposed insects (15.0-15.2 ng/g). Feces from control, bulk, and NP-exposed crickets contained Ce at 248, 393, and 1010 ng/g, respectively. Spiders that consumed crickets from control or bulk treatments contained nonquantifiable Ce; NP-exposed spiders contained Ce at 5.49 ng/g. These findings show that NP CeO2 accumulates in zucchini at greater levels than equivalent bulk materials and that this greater NP intake results in trophic transfer and possible food chain contamination. PMID:25340623

  17. Mode confinement in photonic quasicrystal point-defect cavities for particle accelerators

    NASA Astrophysics Data System (ADS)

    Di Gennaro, E.; Savo, S.; Andreone, A.; Galdi, V.; Castaldi, G.; Pierro, V.; Masullo, M. Rosaria

    2008-10-01

    In this letter, we present a study of the confinement properties of point-defect resonators in finite-size photonic-bandgap structures composed of aperiodic arrangements of dielectric rods, with special emphasis on their use for the design of cavities for particle accelerators. Specifically, for representative geometries, we study the properties of the fundamental mode (as a function of the filling fraction, structure size, and losses) via two-dimensional and three-dimensional full-wave numerical simulations, as well as microwave measurements at room temperature. Results indicate that for reduced-size structures, aperiodic geometries exhibit superior confinement properties by comparison with periodic ones.

  18. Surface mode hybridization in the optical response of core-shell particles

    NASA Astrophysics Data System (ADS)

    Thiessen, E.; Heinisch, R. L.; Bronold, F. X.; Fehske, H.

    2016-03-01

    We present an exact rewriting of the Mie coefficients describing the scattering of light by a spherical core-shell particle which enables their interpretation in terms of a hybridization of the two surface modes arising, respectively, at the core-shell and the shell-medium interface. For this particular case, we thus obtain from the Mie theory—analytically for all multipole orders and hence for arbitrarily sized particles—the hybridization scenario, which so far has been employed primarily for small particles in the electrostatic approximation. To demonstrate the strength of the rewriting approach, we also extract the hybridization scenario for a stratified sphere directly from the expansion coefficients for the electromagnetic fields.

  19. Exploring conformational modes of macromolecular assemblies by multi-particle cryo-EM

    PubMed Central

    Spahn, Christian M.T.; Penczek, Pawel A.

    2009-01-01

    Summary Single particle cryo-electron microscopy (cryo-EM) is a technique aimed at structure determination of large macromolecular complexes in their unconstrained, physiological conditions. The power of the method has been demonstrated in selected studies where for highly symmetric molecules the resolution attained permitted backbone tracing. However, most molecular complexes appear to exhibit intrinsic conformational variability necessary to perform their functions. Therefore, it is now increasingly recognized that sample heterogeneity constitutes a major methodological challenge for cryo-EM. To overcome it dedicated experimental and particularly computational multi-particle approaches have been developed. Their applications point to the future of cryo-EM as an experimental method uniquely suited to visualize the conformational modes of large macromolecular complexes and machines. PMID:19767196

  20. Duality of diffusion dynamics in particle motion in soft-mode turbulence

    NASA Astrophysics Data System (ADS)

    Suzuki, Masaru; Sueto, Hiroshi; Hosokawa, Yusaku; Muramoto, Naoyuki; Narumi, Takayuki; Hidaka, Yoshiki; Kai, Shoichi

    2013-10-01

    Nonthermal Brownian motion is investigated experimentally by injecting a particle into soft-mode turbulence (SMT), in the electroconvection of a nematic liquid crystal. It is clarified that the particle motion can be classified into two phases: fast motion, where particles move with the local convective flow, and slow motion, where they are carried by global slow pattern dynamics. We propose a simplified model to clarify the mechanism of the short-time and asymptotic behavior of diffusion. In our model, the correlation time is estimated as a function of a control parameter ɛ. The scaling of the SMT pattern correlation time, τd˜ɛ-1, is estimated from the particle dynamics, which is consistent with a previous report observed from the Eulerian viewpoint. The origin of the non-Gaussian distribution of the displacement in the short-time regime is also discussed and an analytical curve is introduced that quantitatively agrees with the experimental data. Our results clearly illustrate the characteristics of diffusive motion in SMT, which are considerably different from the conventional Brownian motion.

  1. Interaction of high-energy trapped particles with ballooning modes in a tokamak with a high-. beta. plasma

    SciTech Connect

    Mikhailovskii, A. B.; Novakovaskii, S. V.; Smolyakov, A. I.

    1988-12-01

    A theory is derived for the interaction of high-energy trapped particleswith ballooning modes in a tokamak with a high-..beta.. plasma. A dispersionrelation is derived to describe the ballooning modes in the presence ofsuch particles; the effects of the high plasma ..beta.. are taken into account.The stability boundary for ballooning modes with zero and finite frequenciesis studied. The effects of finite bananas on the stability of ballooningmodes with zero frequencies are determined.

  2. Energetic Particle Effects Can Explain the Low Frequency of Alfvin Modes in the DIII-D Tokamak

    SciTech Connect

    Gorelenkov, N.N.; Heidbrink, W.W.

    2001-01-31

    During beam injection in the DIII-D tokamak, modes with lower frequencies than expected for toroidicity-induced Alfvin eigenmodes (TAE) are often observed. We present the analysis of one of these ''beta-induced Alfvin eigenmodes'' (BAE) with a high-n stability code HINST that includes the effect of the energetic ions on the mode frequency. It shows that the ''BAE'' could be the theoretically predicted resonant-TAE (RTAE), which is also called an energetic-particle mode (EPM).

  3. Comparison of resonant magnetic perturbation-induced particle transport changes in H-mode (DIII-D) and L-mode (MAST)

    NASA Astrophysics Data System (ADS)

    Mordijck, S.; Moyer, R. A.; Kirk, A.; Tamain, P.; Temple, D.; McKee, G. R.; Nardon, E.

    2011-12-01

    Recent experiments show the impact of resonant magnetic perturbations (RMPs) on the density (Schmitz et al 2008 Plasma Phys. Control. Fusion 50 124029, Evans et al 2008 Nucl. Fusion 48 024002, Kirk et al 2008 Nucl. Fusion 50 024002, Liang et al 2007 Phys. Rev. Lett. 98 265004), leading to a so-called density pump-out. Previous comparisons between DIII-D and TEXTOR have focused on the similarities of the deformation of the separatrix and the creation of striations at the intersection of the main chamber wall (Schmitz et al 2008 Plasma Phys. Control. Fusion 50 124029; Schmitz et al 2009 Phys. Rev. Lett. 103 165005). In this paper, we compare the difference in magnitude of the experimentally observed density pump-out in L-mode with H-mode in two diverted tokamaks: MAST and DIII-D. In order to address the differences in magnetic field from the coils, plasma shape and q95 between the two devices, we compute a weighted magnetic diffusion coefficient with a vacuum field line tracing code. This allows us to compare the changes in density pump-out with the weighted magnetic diffusion coefficient, using a simple particle diffusion model. We find that the density pump-out is vastly different in the two confinement regimes, suggesting different particle transport mechanisms. Since one main difference in transport characteristics between L- and H-mode is turbulence, we compare turbulent particle characteristics. We find that in L-mode (MAST) the fluctuations and E × B shear increase at the plasma edge, whereas in H-mode (DIII-D) the fluctuations decrease at the plasma edge. Deeper inside the core, the E × B shear remains similar in L-mode (MAST), whereas a large decrease that quickly saturates with RMP strength is observed in H-mode (DIII-D). These results suggest that the RMP-induced particle transport at the plasma edge in L-mode (MAST) is the result from increases in turbulent particle transport, whereas the results in H-mode (DIII-D) suggest a decrease in turbulent

  4. POWER RECYCLING OF BURST-MODE LASER PULSES FOR LASER PARTICLE INTERACTIONS

    SciTech Connect

    Liu, Yun

    2016-01-01

    A number of laser-particle interaction experiments such as the laser assisted hydrogen ion beam stripping or X-/ -ray generations via inverse-Compton scattering involve light sources operating in a burst mode to match the tem-poral structure of the particle beam. To mitigate the laser power challenge, it is important to make the interaction inside an optical cavity to recycle the laser power. In many cases, conventional cavity locking techniques will not work since the burst normally has a very small duty factor and low repetition rate and it is impossible to gen-erate an effective control signal. This work reports on the development of a doubly-resonant optical cavity scheme and its locking techniques that enables a simultaneous resonance of two laser beams with different spectra and/or temporal structures. We demonstrate that such a cavity can be used to recycle burst-mode ultra-violet laser pulses with arbitrary burst lengths and repetition rates.

  5. Energetic-particle-induced electromagnetic geodesic acoustic mode in tokamak plasmas

    SciTech Connect

    Wang, Lingfeng He, Zhixiong; He, Hongda; Shen, Y.; Dong, J. Q.

    2014-07-15

    Energetic-particle-induced kinetic electromagnetic geodesic acoustic modes (EKEGAMs) are numerically studied in low β (=plasma pressure/magnetic pressure) tokamak plasmas. The parallel component of the perturbed vector potential is considered along with the electrostatic potential perturbation. The effects of finite Larmor radius and finite orbit width of the bulk and energetic ions as well as electron parallel dynamics are all taken into account in the dispersion relation. Systematic harmonic and ordering analysis are performed for frequency and growth rate spectra of the EKEGAMs, assuming (kρ{sub i})∼q{sup −3}∼β≪1, where q, k, and ρ{sub i} are the safety factor, radial component of the EKEGAMs wave vector, and the Larmor radius of the ions, respectively. It is found that there exist critical β{sub h}/β{sub i} values, which depend, in particular, on pitch angle of energetic ions and safety factor, for the mode to be driven unstable. The EKEGAMs may also be unstable for pitch angle λ{sub 0}B<0.4 in certain parameter regions. Finite β effect of the bulk ions is shown to have damping effect on the EKEGAMs. Modes with higher radial wave vectors have higher growth rates. The damping from electron dynamics is found decreasing with decrease of the temperature ratio T{sub e}/T{sub i}. The modes are easily to be driven unstable in low safety factor q region and high temperature ratio T{sub h}/T{sub i} region. The harmonic features of the EKEGAMs are discussed as well.

  6. Burst mode with ps- and fs-pulses: Influence on the removal rate, surface quality, and heat accumulation

    NASA Astrophysics Data System (ADS)

    Neuenschwander, B.; Kramer, Th.; Lauer, B.; Jaeggi, B.

    2015-03-01

    The burst mode for ps and fs pulses for steel and copper is investigated. It is found that the reduction of the energy in a single pulse (in the burst) represents the main factor for the often reported gain in the removal rate using the burst mode e.g. for steel no investigated burst sequence lead to a higher removal rate compared to single pulses at higher repetition rate. But for copper a situation was found where the burst mode leads to a real increase of the removal rate in the range of 20%. Further the burst mode offers the possibility to generate slightly melted flat surfaces with good optical properties in the case of steel. Temperature simulations indicate that the surface state during the burst mode could be responsible for the melting effect or the formation of cavities in clusters which reduces the surface quality.

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

    PubMed

    Kamenetskii, E O

    2010-12-01

    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. PMID:21406763

  8. Collective scattering and oscillation modes of optically bound point particles trapped in a single mode waveguide field.

    PubMed

    Holzmann, Daniela; Ritsch, Helmut

    2015-12-14

    Collective coherent scattering of laser light induces strong light forces between polarizable point particles. These dipole forces are strongly enhanced in magnitude and distance within the field of an optical waveguide so that at low temperature the particles self-order in strongly bound regular patterns. The stationary configurations typically exhibit super-radiant scattering with strong particle and light confinement. Here we study collective excitations of such self-consistent crystalline particle-light structures as function of particle number and pump strength. Multiple scattering and absorption modify the collective particle-field eigenfrequencies and create eigenmodes of surprisingly complex nature. For larger arrays this often leads to dynamical instabilities and disintegration of the structures even if additional damping is present. PMID:26698971

  9. Measurements of Nucleation-Mode Particle Size Distributions in Aircraft Plumes during SULFUR 6

    NASA Technical Reports Server (NTRS)

    Brock, Charles A.; Bradford, Deborah G.

    1999-01-01

    This report summarizes the participation of the University of Denver in an airborne measurement program, SULFUR 6, which was undertaken in late September and early October of 1998 by the Deutsches Zentrum fur Luft und Raumfahrt (DLR). Scientific findings from two papers that have been published or accepted and from one manuscript that is in preparation are presented. The SULFUR 6 experiment was designed to investigate the emissions from subsonic aircraft to constrain calculations of possible atmospheric chemical and climatic effects. The University of Denver effort contributed toward the following SULFUR 6 goals: (1) To investigate the relationship between fuel sulfur content (FSC--mass of sulfur per mass of fuel) and particle number and mass emission index (El--quantity emitted per kg of fuel burned); (2) To provide upper and lower limits for the mass conversion efficiency (nu) of fuel sulfur to gaseous and particulate sulfuric acid; (3) To constrain models of volatile particle nucleation and growth by measuring the particle size distribution between 3 and 100 nm at aircraft plume ages ranging from 10(exp -1) to 10(exp 3) s; (4) To determine microphysical and optical properties and bulk chemical composition of soot particles in aircraft exhaust; and (5) To investigate the differences in particle properties between aircraft plumes in contrail and non-contrail situations. The experiment focused on emissions from the ATTAS research aircraft (a well characterized, but older technology turbojet) and from an in-service Boeing 737-300 aircraft provided by Lufthansa, with modem, high-bypass turbofan engines. Measurements were made from the DLR Dassault Falcon 900 aircraft, a modified business jet. The Atmospheric Effects of Aviation Program (AEAP) provided funding to operate an instrument, the nucleation-mode aerosol size spectrometer (N-MASS), during the SULFUR 6 campaign and to analyze the data. The N-MASS was developed at the University of Denver with the support of

  10. Global particle simulation of lower hybrid wave propagation and mode conversion in tokamaks

    NASA Astrophysics Data System (ADS)

    Bao, J.; Lin, Z.; Kuley, A.

    2015-12-01

    Particle-in-cell simulation of lower hybrid (LH) waves in core plasmas is presented with a realistic electron-to-ion mass ratio in toroidal geometry. Due to the fact that LH waves mainly interact with electrons to drive the current, ion dynamic is described by cold fluid equations for simplicity, while electron dynamic is described by drift kinetic equations. This model could be considered as a new method to study LH waves in tokamak plasmas, which has advantages in nonlinear simulations. The mode conversion between slow and fast waves is observed in the simulation when the accessibility condition is not satisfied, which is consistent with the theory. The poloidal spectrum upshift and broadening effects are observed during LH wave propagation in the toroidal geometry.

  11. Effect of high-energy particles on ballooning flute modes in a tokamak

    SciTech Connect

    Boiko, A.Y.; Cheremnykh, O.K.

    1988-08-01

    A dispersion relation for ideal ballooning flute modes is derived for a tokamak with a finite pressure (..beta../sub theta/approx. =1), a large aspect ratio, circular magnetic surfaces, and a group of high-energy particles assuming that the potential wells are shallow. In addition to waves which are already known, this dispersion relation describes two neutrally stable natural wave branches with frequencies ..omega..approx. <..omega../sub */, where ..omega../sub */ is the ion drift frequency. Either untrapped or trapped ions can excited one of these branches (with the higher frequency) and can damp the other (with the lower frequency). Analytic expressions are derived for the growth rate and the damping rate. The results found here can be used to explain the fishbone oscillations which have been observed experimentally.

  12. Global particle simulation of lower hybrid wave propagation and mode conversion in tokamaks

    SciTech Connect

    Bao, J.; Lin, Z.; Kuley, A.

    2015-12-10

    Particle-in-cell simulation of lower hybrid (LH) waves in core plasmas is presented with a realistic electron-to-ion mass ratio in toroidal geometry. Due to the fact that LH waves mainly interact with electrons to drive the current, ion dynamic is described by cold fluid equations for simplicity, while electron dynamic is described by drift kinetic equations. This model could be considered as a new method to study LH waves in tokamak plasmas, which has advantages in nonlinear simulations. The mode conversion between slow and fast waves is observed in the simulation when the accessibility condition is not satisfied, which is consistent with the theory. The poloidal spectrum upshift and broadening effects are observed during LH wave propagation in the toroidal geometry.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Multipolar resonant particle modes as elementary excitations in chain waveguides: Theory, dispersion relations and mathematical modeling

    NASA Astrophysics Data System (ADS)

    Serebrennikov, Aleksey M.

    2011-10-01

    In the framework of linear electrodynamics, the theory of the resonant interaction of multipolar modes in the many body system and associated numerical techniques are proposed in the present paper. The theory rests upon certain integral field equations derived on the basis of the Stratton-Chu integral transforms, the Atkinson-Wilcox and multipole expansions. For the case of spherical geometry of the bodies, the half part of these field equations is reduced to a set of closed form dispersion relations which describe the excitation of nonradiating modes in the particle cluster of arbitrary complexity. For clusters with developed translation symmetry, we propose the method for solving the field equations which is characterized by an effective numerical scaling. For perfectly periodic one dimensional systems (chains), this scaling has a linear character. On the basis of the proposed theory and numerical technique the method of synthesis of chain plasmonic waveguides with low radiation losses is considered. Different checks targeted on the verification of the approaches are fulfilled.

  15. Particle penetration into the automotive interior. I. Influence of vehicle speed and ventilatory mode.

    PubMed

    Muilenberg, M L; Skellenger, W S; Burge, H A; Solomon, W R

    1991-02-01

    Penetration of particulate aeroallergens into the interiors of two, new, similar Chrysler Corporation passenger vehicles (having no evidence of intrinsic microbial contamination) was studied on a large circular test track during periods of high pollen and spore prevalence. Impactor collections were obtained at front and rear seat points and at the track center during periods with (1) windows and vents closed and air conditioning on, (2) windows closed, vents open, and no air conditioning, and (3) air conditioner off, front windows open, and vents closed. These conditions were examined sequentially during travel at 40, 50, 60, and 80 kph. Particle recoveries within the two, new, similar Chrysler Corporation passenger vehicles did not vary with the speed of travel, either overall or with regard to each of the three ventilatory modalities. In addition, collections at front and rear seat sampling points were comparable. Highest interior aeroallergen levels were recorded with WO, and yet, these levels averaged only half the concurrent outside concentrations at track center. Recoveries within the cars were well below recoveries obtained outside when windows were closed (both VO and AC modes). These findings suggest window ventilation as an overriding factor determining particle ingress into moving vehicles. Efforts to delineate additional determinants of exposure by direct sampling are feasible and would appear essential in formulating realistic strategies of avoidance. PMID:1993816

  16. Velocity Measurement in a Dual-Mode Supersonic Combustor using Particle Image Velocimetry

    NASA Technical Reports Server (NTRS)

    Goyne, C. P.; McDaniel, J. C.; Krauss, R. H.; Day, S. W.; Reubush, D. E. (Technical Monitor); McClinton, C. R. (Technical Monitor); Reubush, D. E.

    2001-01-01

    Temporally and spatially-resolved, two-component measurements of velocity in a supersonic hydrogen-air combustor are reported. The combustor had a single unswept ramp fuel injector and operated with an inlet Mach number of 2 and a flow total temperature approaching 1200 K. The experiment simulated the mixing and combustion processes of a dual-mode scramjet operating at a flight Mach number near 5. The velocity measurements were obtained by seeding the fuel with alumina particles and performing Particle Image Velocimetry on the mixing and combustion wake of the ramp injector. To assess the effects of combustion on the fuel air-mixing process, the distribution of time-averaged velocity and relative turbulence intensity was determined for the cases of fuel-air mixing and fuel-air reacting. Relative to the mixing case, the near field core velocity of the reacting fuel jet had a slower streamwise decay. In the far field, downstream of 4 to 6 ramp heights from the ramp base, the heat release of combustion resulted in decreased flow velocity and increased turbulence levels. The reacting measurements were also compared with a computational fluid dynamics solution of the flow field. Numerically predicted velocity magnitudes were higher than that measured and the jet penetration was lower.

  17. Wave-particle dualism and complementarity unraveled by a different mode

    PubMed Central

    Menzel, Ralf; Puhlmann, Dirk; Heuer, Axel; Schleich, Wolfgang P.

    2012-01-01

    The precise knowledge of one of two complementary experimental outcomes prevents us from obtaining complete information about the other one. This formulation of Niels Bohr’s principle of complementarity when applied to the paradigm of wave-particle dualism—that is, to Young’s double-slit experiment—implies that the information about the slit through which a quantum particle has passed erases interference. In the present paper we report a double-slit experiment using two photons created by spontaneous parametric down-conversion where we observe interference in the signal photon despite the fact that we have located it in one of the slits due to its entanglement with the idler photon. This surprising aspect of complementarity comes to light by our special choice of the TEM01 pump mode. According to quantum field theory the signal photon is then in a coherent superposition of two distinct wave vectors giving rise to interference fringes analogous to two mechanical slits. PMID:22628561

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

    NASA Technical Reports Server (NTRS)

    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.

  19. Efficient polyhydroxyalkanoate (PHA) accumulation by a new continuous feeding mode in three-stage mixed microbial culture (MMC) PHA production process.

    PubMed

    Chen, Zhiqiang; Huang, Long; Wen, Qinxue; Guo, Zirui

    2015-09-10

    A new continuous feeding mode was developed to optimize the polyhydroxyalkanoates (PHAs) accumulation step in the three-stage PHAs production process by mixed microbial cultures (MMCs) using mixed volatile fatty acids (VFAs) as substrate. The continuous feeding assays under low biomass loading rate (BLR) (in the range of 3.5-5.5Cmol VFA/Cmol X/d) can be directly fed with feedstock with pH from 5.0 to 10.0 without any pH regulation. The maximum intracellular PHA content of 70.4% and system PHA yield (YPHA/S(sys)) of 0.81Cmol PHA/Cmol VFA were achieved under the continuous feeding mode at BLR of 3.86Cmol VFA/Cmol X/d when directly fed with substrate at pH 5. These values were higher than those under the pulse wise feeding mode with the same substrate and active biomass concentration. The results indicated that a self-balanced pH state was formed in the continuous feeding system. Further studies on the reaction pH and kinetics of the MMCs in the continuous feeding reactor were conducted to understand the pH variation mechanism and accumulation process. The optimal BLR to get high PHA content and YPHA/S(sys) was 3.5-5.5Cmol VFA/Cmol X/d. PMID:26073996

  20. Volatile properties of particles emitted by compressed natural gas and diesel buses during steady-state and transient driving modes.

    PubMed

    Jayaratne, E R; Meyer, N K; Ristovski, Z D; Morawska, L

    2012-01-01

    Volatile properties of particle emissions from four compressed natural gas (CNG) and four diesel buses were investigated under steady-state and transient driving modes on a chassis dynamometer. The exhaust was diluted utilizing a full-flow continuous volume sampling system and passed through a thermodenuder at controlled temperature. Particle number concentration and size distribution were measured with a condensation particle counter and a scanning mobility particle sizer, respectively. We show that while almost all the particles emitted by the CNG buses were in the nanoparticle size range, at least 85% and 98% were removed at 100 and 250 °C, respectively. Closer analysis of the volatility of particles emitted during transient cycles showed that volatilization began at around 40 °C, with the majority occurring by 80 °C. Particles produced during hard acceleration from rest exhibited lower volatility than those produced during other times of the cycle. On the basis of our results and the observation of ash deposits on the walls of the tailpipes, we suggest that these nonvolatile particles were composed mostly of ash from lubricating oil. Heating the diesel bus emissions to 100 °C removed ultrafine particle numbers by 69-82% when a nucleation mode was present and just 18% when it was not. PMID:22107263

  1. Effect of particle size on their accumulation in an inflammatory lesion in a dextran sulfate sodium (DSS)-induced colitis model.

    PubMed

    Watanabe, Ayaka; Tanaka, Hiroki; Sakurai, Yu; Tange, Kota; Nakai, Yuta; Ohkawara, Tatsuya; Takeda, Hiroshi; Harashima, Hideyoshi; Akita, Hidetaka

    2016-07-25

    Taking advantage of the enhanced permeation and retention (EPR) effect is a promising approach for delivering macromolecules or nanoparticles to tumors. Recent studies revealed that this strategy is also applicable for targeting other pathological lesions (i.e. inflammatory disease). In the present study, we report the optimal size of a nanoparticle for allowing the higher accumulation of a particle in an inflammatory lesion using a dextran sulfate sodium (DSS)-induced colitis model. As a nanoparticle platform, we utilized a SS-cleavable and pH-activated lipid-like material (ssPalm), that can be used to produce particles in a variety of sizes ranging from 50nm to 180nm while using the same lipid composition. In healthy mice, particle accumulation remained low regardless of size. In contrast, the accumulation in inflammatory colon tissue was enhanced depending on the progress of the inflammation. In this situation, the apparent uptake clearance accumulation of a mid-sized particle (113nm on average) was higher than that for smaller and larger (54nm and 183nm in average, respectively) ones. Therefore, controlling particle size is an important parameter for the extensive targeting of inflammatory lesion. PMID:27231121

  2. The Effect of Shape Mode Oscillations on the Particle Scavenging Efficiency of Water Droplets Using Acoustic Levitation

    NASA Astrophysics Data System (ADS)

    Kizzee, J.; Saylor, J. R.

    2010-11-01

    The effect of drop oscillations on the scavenging of solid particles is studied using an ultrasonic transducer to levitate a water droplet in an airflow of particles. Shape mode oscillations are induced in the drop by modulating the acoustic field used for levitation. The effect of oscillation frequency, the oscillation amplitude, and the drop diameter on the scavenging of particles is presented. The particle diameters are on the order of 1μm and the drop diameters are on the order of 1mm. Although single droplets are studied here, the application of interest is improved scavenging of particles by spray drops. Specifically, improving the elimination of coal dust particles from mines using waters sprays excited ultrasonically is of interest.

  3. THE DEVELOPMENT OF MODE-CHOICE SIMULATOR WITH THE LOG DATA ACCUMULATED IN ON-DEMAND BUS SERVER

    NASA Astrophysics Data System (ADS)

    Tsubouchi, Kota; Yamato, Hiroyuki; Hiekata, Kazuo

    The new simulator which can estimate the mode-choi ce in the area was developed and evaluated in the field test. The characteristic of the developed simulato r is to be able to estimate the number of demand and demand pattern in high-accuracy with the real operation log data of the On-demand Bus. The simulator is devided into micro-simulator whose passenger agents choose their transpor t mode by the sacrifice model. The developed simulator is evaluated in the real fi eld test in Sakai City, Osaka Prefecture. The new transportation like LRT (Light Rail Transit) and On-demand Bus is eval uated by the simulator and the result of simulation is confirmed to be reliable by the local government officers.

  4. The composition of nucleation and Aitken modes particles during coastal nucleation events: evidence for marine secondary organic contribution

    NASA Astrophysics Data System (ADS)

    Vaattovaara, P.; Huttunen, P. E.; Yoon, Y. J.; Joutsensaari, J.; Lehtinen, K. E. J.; O'Dowd, C. D.; Laaksonen, A.

    2006-04-01

    Newly-formed nanometer-sized particles have been observed at coastal and marine environments worldwide. Interestingly, organic species have so far not been detected in those newly-formed nucleation mode particles. In this study, we applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer) method to study the possible existence of an organic fraction in recently formed coastal nucleation mode particles (d<20 nm) at the Mace Head research station. Furthermore, effects of those nucleation events to potential CCN (cloud condensation nuclei) were studied. The coastal events were typical for the Mace Head region and they occurred at low tide conditions during efficient solar radiation and high biological activity (HBA, i.e. a high mass concentration of chlorophyll a of the ocean) in spring 2002. Additionally, a PHA-UCPC (pulse height analyzer ultrafine condensation particle counter) technique was used to study the composition of newly-formed particles formed in low tide conditions during a lower biological activity (LBA, i.e. a lower mass concentration of chlorophyll a of the ocean) in October 2002. The overall results of the UFO-TDMA and the PHA-UCPC measurements indicate that those coastally/marinely formed nucleation mode particles include a remarkable fraction of secondary organic products, beside iodine oxides, which are likely to be responsible for the nucleation. During clean marine air mass conditions, the origin of those secondary organic oxidation compounds can be related to marine/coastal biota and thus a major fraction of the organics may originate from biosynthetic production of alkenes such as isoprene and their oxidation by iodine, hydroxyl radical, and ozone. During modified marine conditions, also anthropogenic secondary organic compounds may contribute to the nucleation mode organic mass, in addition to biogenic secondary organic compounds. Thus, the UFO-TDMA results suggest that the secondary organic compounds may, in addition to

  5. Investigation of Particle Accumulation, Chemosensitivity and Thermosensitivity for Effective Solid Tumor Therapy Using Thermosensitive Liposomes and Hyperthermia

    PubMed Central

    Lokerse, Wouter J.M.; Bolkestein, Michiel; ten Hagen, Timo L.M.; de Jong, Marion; Eggermont, Alexander M.M.; Grüll, Holger; Koning, Gerben A.

    2016-01-01

    Doxorubicin (Dox) loaded thermosensitive liposomes (TSLs) have shown promising results for hyperthermia-induced local drug delivery to solid tumors. Typically, the tumor is heated to hyperthermic temperatures (41-42 °C), which induced intravascular drug release from TSLs within the tumor tissue leading to high local drug concentrations (1-step delivery protocol). Next to providing a trigger for drug release, hyperthermia (HT) has been shown to be cytotoxic to tumor tissue, to enhance chemosensitivity and to increase particle extravasation from the vasculature into the tumor interstitial space. The latter can be exploited for a 2-step delivery protocol, where HT is applied prior to i.v. TSL injection to enhance tumor uptake, and after 4 hours waiting time for a second time to induce drug release. In this study, we compare the 1- and 2-step delivery protocols and investigate which factors are of importance for a therapeutic response. In murine B16 melanoma and BFS-1 sarcoma cell lines, HT induced an enhanced Dox uptake in 2D and 3D models, resulting in enhanced chemosensitivity. In vivo, therapeutic efficacy studies were performed for both tumor models, showing a therapeutic response for only the 1-step delivery protocol. SPECT/CT imaging allowed quantification of the liposomal accumulation in both tumor models at physiological temperatures and after a HT treatment. A simple two compartment model was used to derive respective rates for liposomal uptake, washout and retention, showing that the B16 model has a twofold higher liposomal uptake compared to the BFS-1 tumor. HT increases uptake and retention of liposomes in both tumors models by the same factor of 1.66 maintaining the absolute differences between the two models. Histology showed that HT induced apoptosis, blood vessel integrity and interstitial structures are important factors for TSL accumulation in the investigated tumor types. However, modeling data indicated that the intraliposomal Dox fraction did not

  6. The triaxial particle plus rotor model and wobbling mode: A semiclassical view

    SciTech Connect

    Gupta, Rajiv; Malik, S. S.; Jain, A. K.; Jain, S. R.

    2010-11-24

    A systematic analysis of the triaxial particle rotor model with single-j shell configuration is carried out to explain the prominent features of observed wobbling excitations in odd A nuclei. The equations of motion for the angular momentum vectors I-vector and j-vector generate two types of equilibrium (i.e., (i) the axes aligned and (ii) the planar) states. The planar equilibrium states involve mainly the orientation degree of freedom {gamma} and their Jacobian matrix J gives purely imaginary eigenvalues in conjugate pairs. Also, our dynamical results show a substantial projection of angular momentum vectors on all the three principal axes, which implies that the resultant angular momentum lies outside the planes of three axes. Both these signatures confirm the spontaneous breakdown of time reversal (T) plus rotation by 180 deg. (R{sub {pi}}) i.e., R{sub {pi}T} symmetry and as a result nearly two identical bands consisting of even and odd spins emerge. We have tested our dynamical formalism for the wobbling mode observed in {sup 163}Lu.

  7. Fluid electrons with kinetic closure for long wavelength energetic particles driven modes

    SciTech Connect

    Chen Yang; Parker, Scott E.

    2011-05-15

    A kinetic electron closure scheme is presented for the fluid electron model that has been implemented in the GEM code [J. Lang, Y. Chen, S. E. Parker, and G.-Y. Fu, Phys. Plasmas 16, 102101 (2009)]. The most important element of the closure scheme is a complete Ohm's law for the parallel electric field E{sub ||}, derived by combining the quasineutrality condition, the Ampere's equation and the v{sub ||} moment of the gyrokinetic equations. A discretization method for the closure scheme is presented and studied in detail for a three-dimensional shearless slab plasma. It is found that for long wavelength shear Alfven waves the kinetic closure scheme is both more accurate and more robust than the previous GEM algorithm [Y. Chen and S. E. Parker, J. Comput. Phys. 189, 463 (2003)], whereas for the ion-gradient-driven instability the previous algorithm is more efficient. The fluid electron model with kinetic electron closure is useful for studying energetic particles driven modes with electron kinetic damping effects.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Particle simulation of radio frequency stabilization of the flute mode in a tandem mirror. II. Perpendicular antenna

    SciTech Connect

    Abe, H.; Kadoya, Y.

    1988-10-01

    A two-and-a-half-dimensional electromagnetic particle code PS2M (J. Phys. Soc. Jpn. 56, 3899 (1987)) is used to study how an electric field applied perpendicularly to the magnetic field affects the radio frequency stabilization of flute modes in a tandem mirror plasma. The electric field perpendicular to the magnetic field stabilizes or destabilizes the flute mode through the mechanism of the ponderomotive force acting on electrons and ions and through the mechanism of sideband coupling. In the simulations two typical examples have been shown: (i) when the sideband coupling effects (in which the electron terms are dominant) stabilize the flute modes and (ii) when the perpendicular ponderomotive force acting on the electrons destabilizes the flute modes.

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

    PubMed

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

    2016-01-01

    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. PMID:27580515

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

    PubMed Central

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

    2016-01-01

    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. PMID:27580515

  12. Fast-particle-driven Alfvénic modes in a reversed field pinch.

    PubMed

    Koliner, J J; Forest, C B; Sarff, J S; Anderson, J K; Liu, D; Nornberg, M D; Waksman, J; Lin, L; Brower, D L; Ding, W X; Spong, D A

    2012-09-14

    Alfvénic 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 Alfvénic scaling is observed. PMID:23005639

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Non-perturbative modelling of energetic particle effects on resistive wall mode: Anisotropy and finite orbit width

    SciTech Connect

    Liu, Yueqiang Chapman, I. T.; Hao, G. Z.; Wang, Z. R.; Menard, J. E.; Okabayashi, M.; Strait, E. J.; Turnbull, A.

    2014-05-15

    A non-perturbative magnetohydrodynamic-kinetic hybrid formulation is developed and implemented into the MARS-K code [Liu et al., Phys. Plasmas 15, 112503 (2008)] that takes into account the anisotropy and asymmetry [Graves et al., Nature Commun. 3, 624 (2012)] of the equilibrium distribution of energetic particles (EPs) in particle pitch angle space, as well as first order finite orbit width (FOW) corrections for both passing and trapped EPs. Anisotropic models, which affect both the adiabatic and non-adiabatic drift kinetic energy contributions, are implemented for both neutral beam injection and ion cyclotron resonant heating induced EPs. The first order FOW correction does not contribute to the precessional drift resonance of trapped particles, but generally remains finite for the bounce and transit resonance contributions, as well as for the adiabatic contributions from asymmetrically distributed passing particles. Numerical results for a 9MA steady state ITER plasma suggest that (i) both the anisotropy and FOW effects can be important for the resistive wall mode stability in ITER plasmas; and (ii) the non-perturbative approach predicts less kinetic stabilization of the mode, than the perturbative approach, in the presence of anisotropy and FOW effects for the EPs. The latter may partially be related to the modification of the eigenfunction of the mode by the drift kinetic effects.

  15. Recrystallization of bulk and plasma-coated tungsten with accumulated thermal energy relevant to Type-I ELM in ITER H-mode operation

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Su; Lim, Sun-Taek; Jin, Younggil; Lee, Jin Young; Song, Jae-Min; Kim, Gon-Ho

    2015-08-01

    The recrystallization of bulk tungsten is investigated under various thermal loads that are relevant to the accumulation energy during Type-I ELM in ITER H-mode operation. A thermal plasma torch is used to examine only the thermal load effect on the material; therefore, the charge and atomic effects are ignored. In this condition, recrystallization is observed in bulk W with a surface temperature above 1700 °C. The effect becomes severe with a finite recrystallization thickness near the surface, which introduces vertical cracking along grain boundaries with increasing thermal load. However, plasma-sprayed tungsten (PS-W) is not crystallized because neighboring lamellas merge, destroying their interlayer and producing no vertical cracks. This is attributed to an annealing effect in PS-W. Therefore, these results suggest that a multilayer W structure is advantageous in the fabrication of W, especially for long pulse operation in a future fusion reactor.

  16. Global Geodesic Acoustic Modes Driven by Energetic Particles in the DIII-D Tokamak

    NASA Astrophysics Data System (ADS)

    Nazikian, R.; Fu, G. Y.; Gorelenkov, N. N.; Kramer, G. J.; Austin, M. E.; Berk, H. L.; Heidbrink, W. W.; McKee, G. R.; Shafer, M. W.; Strait, E. J.; van Zeeland, M. A.

    2009-11-01

    Intense axisymmetric oscillations driven by suprathermal passing ions injected in the direction counter to the toroidal plasma current are observed in the DIII-D tokamak. Strong bursting and frequency chirping coincide with large (10-15%) drops in the neutron emission, suggesting that the mode is very effective in displacing beam ions from the plasma core. BES measurements of density fluctuations indicate an outward propagating mode of large radial extent. The large density to temperature ratio of the mode confirms a dominant compressional contribution to the pressure perturbation, indicative of the Geodesic Acoustic Mode (GAM).

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    Reid, Jeffrey S.; Brooks, Barbara; Crahan, Katie K.; Hegg, Dean A.; Eck, Thomas F.; O'Neill, Norm; de Leeuw, Gerrit; Reid, Elizabeth A.; Anderson, Kenneth D.

    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 the subtropical marine Pacific site. Here we examine coarse mode particle size distributions. Similar to what has been shown for airborne dust, optical particle counters such as the Forward Scattering Spectrometer Probe (FSSP), Classical Scattering Aerosol Spectrometer Probe (CSASP) and the Cloud Aerosol Spectrometer (CAS) within the Cloud Aerosol and Precipitation Spectrometer (CAPS) instrument systematically overestimate particle size, and consequently volume, for sea salt particles. Ground-based aerodynamic particle sizers (APS) and AERONET inversions yield much more reasonable results. A wing pod mounted APS gave mixed results and may not be appropriate for marine boundary layer studies. Relating our findings to previous studies does much to explain the bulk of the differences in the literature and leads us to conclude that the largest uncertainty facing flux and airborne cloud/aerosol interaction studies is likely due to the instrumentation itself. To our knowledge, there does not exist an in situ aircraft system that adequately measures the ambient volume distribution of coarse mode sea salt particles. Most empirically based sea salt flux parameterizations can trace their heritage to a clearly biased measurement technique. The current "state of the art" in this field prevents any true form of clear sky radiative "closure" for clean marine environments.

  19. Uptake and accumulation of bulk and nanosized cerium oxide particles and ionic cerium by radish (Raphanus sativus L.).

    PubMed

    Zhang, Weilan; Ebbs, Stephen D; Musante, Craig; White, Jason C; Gao, Cunmei; Ma, Xingmao

    2015-01-21

    The potential toxicity and accumulation of engineered nanomaterials (ENMs) in agricultural crops has become an area of great concern and intense investigation. Interestingly, although below-ground vegetables are most likely to accumulate the highest concentrations of ENMs, little work has been done investigating the potential uptake and accumulation of ENMs for this plant group. The overall objective of this study was to evaluate how different forms of cerium (bulk cerium oxide, cerium oxide nanoparticles, and the cerium ion) affected the growth of radish (Raphanus sativus L.) and accumulation of cerium in radish tissues. Ionic cerium (Ce(3+)) had a negative effect on radish growth at 10 mg CeCl3/L, whereas bulk cerium oxide (CeO2) enhanced plant biomass at the same concentration. Treatment with 10 mg/L cerium oxide nanoparticles (CeO2 NPs) had no significant effect on radish growth. Exposure to all forms of cerium resulted in the accumulation of this element in radish tissues, including the edible storage root. However, the accumulation patterns and their effect on plant growth and physiological processes varied with the characteristics of cerium. This study provides a critical frame of reference on the effects of CeO2 NPs versus their bulk and ionic counterparts on radish growth. PMID:25531028

  20. Variational symplectic particle-in-cell simulation of nonlinear mode conversion from extraordinary waves to Bernstein waves

    SciTech Connect

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

    2015-09-15

    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 current drive experiments.

  1. Global-mode Pc 5 pulsations: Ground distribution and correlation with energetic particles in the inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Yousif Suliman, M. E.; Yumoto, K.; Yoshikawa, A.; Uozumi, T.; Kawano, H.; Abe, S.; Cardinal, M. G.; Winkler, L. I.

    2012-12-01

    A sound history has been well known for decades concerning the studies of the correlations between high energetic electrons in the radiation belts and ULF magnetic pulsations, especially in the Pc 5 range in recent papers. Still, there remain open questions on which many researches are currently working. One of such questions is: Is there some kind of global-mode Pc 5 pulsations which enhances the density of high energetic particles in the inner magnetosphere? This question has motivated this study on the existence of such a global mode of Pc 5 pulsations at mid-latitudes. In this study we have identified global-mode Pc 5 geomagnetic pulsations as those simultaneously observed at three mid-latitude MAGDAS/CPMN ground stations separated by ~120deg in longitude from each other, and studied their features and their correlations with solar wind parameters and high energetic particles in the radiation belts. The specific selection criteria of the global-mode Pc 5 pulsation is as follows: Each Pc 5 event at each station must have large amplitudes (larger than 0.4nT at L<2, larger than 1.0nT at L>3) and long life periods (at least two hours). (Such criteria are relatively strict comparing with past studies but suitable for continuous monitoring of Pc 5 pulsations.) Furthermore, each event must be simultaneously observed at all the three ground stations. Detailed nature of thus identified global Pc 5 pulsations will be discussed in the presentation.

  2. Plasmonic nanoparticles sensors utilizing hybrid modes, electrical excitation, and anisotropic particles

    NASA Astrophysics Data System (ADS)

    Dathe, Andre; Kliuiev, Pavel; Jatschka, Jacqueline; Hübner, Uwe; Ziegler, Mario; Thiele, Matthias; Trautmann, Steffen; Wirth, Janina; Garwe, Frank; Csaki, Andrea; Stranik, Ondrej; Fritzsche, Wolfgang

    2015-08-01

    Surface Plasmon Resonance (SPR) in metallic nanostructures is an optical effect that can be exploited for the detection of small molecules. There is a broad range of metallic nanostructures supporting different SPR modes, and nanostructures can be even geometrically combined leading to the creation of new hybridised SPR modes. In our study, we investigated the properties of a hybridised SPR mode (gap modes GM) created by the placement of metallic nanoparticles onto metallic layers and its use as a sensitive sensor. A tunneling current passing through a metal-insulator-semiconductor structure can generate supported SPR modes that can be scattered through GM, which was experimentally confirmed. Moreover, we were able to experimentally follow the degradation of anisotropic (silver nanoprism) nanoparticles under ambient conditions in real time. Using atomic force microscopy and optical spectroscopy we observed an anisotropic corrosion that is starting from the tips of the nanoparticles.

  3. Turbulent particle transport as a function of toroidal rotation in DIII-D H-mode plasmas

    NASA Astrophysics Data System (ADS)

    Wang, X.; Mordijck, S.; Zeng, L.; Schmitz, L.; Rhodes, T. L.; Doyle, E. J.; Groebner, R.; Meneghini, O.; Staebler, G. M.; Smith, S. P.

    2016-04-01

    In this paper we show how changes in toroidal rotation, by controlling the injected torque, affect particle transport and confinement. The toroidal rotation is altered using the co- and counter neutral beam injection (NBI) in low collisionality H-mode plasmas on DIII-D (Luxon 2002 Nucl. Fusion 42 614) with dominant electron cyclotron heating (ECH). We find that there is no correlation between the toroidal rotation shear and the inverse density gradient, which is observed on AUG when {{T}\\text{e}}/{{T}\\text{i}} is varied using ECH (Angioni et al 2011 Phys. Rev. Lett. 107 215003). In DIII-D, we find that in a discharge with balanced torque injection, the E× B shear is smaller than the linear gyrokinetic growth rate for small {{k}θ}{ρs} for ρ =0.6 -0.85. This results in lower particle confinement. In the co- and counter- injected discharges the E× B shear is larger or close to the linear growth rate at the plasma edge and both configurations have higher particle confinement. In order to measure particle transport, we use a small periodic perturbative gas puff. This gas puff perturbs the density profiles and allows us to extract the perturbed diffusion and inward pinch coefficients. We observe a strong increase in the inward particle pinch in the counter-torque injected plasma. Finally, the calculated quasi-linear particle flux, nor the linear growth rates using TGLF (Staebler et al 2005 Phys. Plasmas 12 102508) agree with experimental observations.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Generation of Small-Mode Particles via Nucleation of Meteoric Dust in the Upper Haze of Venus

    NASA Astrophysics Data System (ADS)

    Yung, Yuk; Gao, P.; Zhang, X.; Crisp, D.; Bardeen, C. G.

    2012-10-01

    Observations by the SPICAV/SOIR instruments aboard Venus Express has revealed that the Upper Haze of Venus is populated by two particle modes, as reported by Wilquet et al. (J. Geophys. Res., 114, E00B42, 13pp, 2009). In this work we posit that the large mode is due to the upwelling of cloud particles, while the smaller mode is generated by the nucleation of meteoric dust. We test this hypothesis by using version 3.0 of the Community Aerosol and Radiation Model for Atmospheres, first developed by Turco et al. (J. Atmos. Sci., 36, 699-717, 1979) and upgraded by Bardeen et al. (The CARMA 3.0 microphysics package in CESM, Whole Atmosphere Working Group Meeting, 2011). Using the meteoric dust production profile of Kalashnikova et al. (Geophys. Res. Lett., 27, 3293-3296, 2000), the sulfur/sulfate condensation nuclei production profile of Imamura and Hashimoto (J. Atmos. Sci., 58, 3597-3612, 2001), and sulfuric acid vapour production profile of Zhang et al. (Icarus, 217, 714-739, 2012), we numerically simulate a column of the Venus atmosphere from 40 to 100 km above the surface. Our aerosol number density results agree well with Pioneer Venus data from Knollenberg and Hunten (J. Geophys. Res., 85, 8039-8058, 1980), while our gas distribution results match that of Kolodner and Steffes (Icarus, 132, 151-169, 1998). There is a mediocre agreement between our cloud deck size distribution and Pioneer Venus data. The Upper Haze size distribution shows two lognormal distributions overlapping each other, possibly indicating the presence of two modes, though more analysis is required at this time. Finally, we treat the simulated aerosol particles as Mie scatterers and compute their optical parameters. The results show a minimum in the optical depth at a wavelength of 300 nm, comparable to the results of Lacis (J. Atmos. Sci., 32, 1107-1124, 1975).

  6. Indirect evidence of the composition of nucleation mode atmospheric particles in the high Arctic

    NASA Astrophysics Data System (ADS)

    Giamarelou, Maria; Eleftheriadis, Konstantinos; Nyeki, Stephan; Tunved, Peter; Torseth, Kjetil; Biskos, George

    2016-01-01

    Previous long-term observations have shown that nanoparticle formation events are common in the summer-time high Arctic and linked to local photochemical activity. However, current knowledge is limited with respect to the chemical precursors of resulting nanoparticles and the compounds involved in their subsequent growth. Here we report case-study measurements during new particle formation (NPF) events of the particle size distribution (diameter > 7 nm) and for the first time the volatility of monodisperse particles having diameter ≤40 nm, providing indirect information about their composition. Volatility measurements provide indirect evidence that a predominant fraction of the 12 nm particle population is ammoniated sulfates in the summertime high Arctic. Our observations further suggest that the majority of the sub-40 nm particle population during NPF events does not exist in the form of sulfuric acid but rather as partly or fully neutralized ammoniated sulfates.

  7. Laser-based measurements of magnetic fluctuation-induced particle transport and nonlinear mode interactions in the Madison Symmetric Torus reversed-field pinch

    NASA Astrophysics Data System (ADS)

    Yates, Travis Fred

    Magnetic fluctuation-induced particle transport and density fluctuations have been investigated in the Madison Symmetric Torus (MST) reversed-filed pinch using a far infrared (FIR) laser based interferometer-polarimetry system. An extensive study focuses on the particle transport and density fluctuations during the sawtooth crash where the stochastic magnetic field is largest. Particle flux arising from the inieraction between density fluctuations and magnetic fluctuations has been measured to be significant at the reversal surface where modes with poloidal mode number m = 0 are resonant. The particle flux is comparable to that measured in the core where m = 1 modes dominate. The origin of density fluctuations has been studied experimentally. It is found that density fluctuations not only result from linear advection but also non-linear three-wave interactions. This is different from the previously reported results that indicated that the edge density fluctuations originate from linear advection. The results reported here reveal that m = 0 modes play an important role in density fluctuations and particle flux. An experiment where m = 0 modes are greatly reduced, by removing the reversal surface from the plasma, indicates that particle flux and density fluctuations are reduced significantly, which further confirms the importance of edge resonant modes in particle transport.

  8. Electromagnetic particle simulation of the effect of toroidicity on linear mode conversion and absorption of lower hybrid waves

    NASA Astrophysics Data System (ADS)

    Bao, J.; Lin, Z.; Kuley, A.; Wang, Z. X.

    2016-06-01

    Effects of toroidicity on linear mode conversion and absorption of lower hybrid (LH) waves in fusion plasmas have been studied using electromagnetic particle simulation. The simulation confirms that the toroidicity induces an upshift of parallel refractive index when LH waves propagate from the tokamak edge toward the core, which affects the radial position for the mode conversion between slow and fast LH waves. Furthermore, moving LH antenna launch position from low field side toward high field side leads to a larger upshift of the parallel refractive index, which helps the slow LH wave penetration into the tokamak core. The broadening of the poloidal spectrum of the wave-packet due to wave diffraction is also verified in the simulation. Both the upshift and broadening effects of the parallel spectrum of the wave-packet modify the parallel phase velocity and thus the linear absorption of LH waves by electron Landau resonance.

  9. Wave-Particle Interaction Analyzer for the Pitch Angle Scattering of Electrons by Whistler-mode Chorus Emissions

    NASA Astrophysics Data System (ADS)

    Kitahara, M.; Katoh, Y.

    2015-12-01

    Pitch angle scattering of electrons caused by chorus emissions is one of significant wave-particle interactions in the magnetosphere. A number of previous studies treat the pitch angle scattering as a diffusion of distribution function and calculate diffusion coefficients from observed wave spectra. However, in the diffusion model, we cannot evaluate the nonlinearity of the pitch angle scattering, while recent theoretical works and observation results have pointed out the importance of nonlinear effects. A concept of Wave-Particle Interaction Analysis (WPIA) is proposed by Fukuhara et al. (2009). In the frame of the WPIA, we can directly detect wave-particle interactions by calculating the energy exchange between waves and particles. In the present study, in addition to the method to detect the energy exchange, we propose a method to directly detect the pitch angle scattering of resonant particles by calculating G. The G is defined as the accumulation value of a pitch angular component of the Lorentz force acting on each particle. We apply the proposed method to results of the one-dimensional electron hybrid simulation (Katoh and Omura, 2007a, b). By using the wave and particle data obtained at fixed points assumed in the simulation system, we conduct the pseudo-observation in the simulation. In the result of the analysis, we obtain significant values of G for electrons in the kinetic energy and pitch angle ranges satisfying the cyclotron resonance condition. We compare the result of the analysis of G with the temporal variation of both the pitch angle distributions and the wave spectra. While the pitch angle distribution varies by a few percent through interactions, we obtain the statistically significant G. Furthermore, we compare the G with diffusion coefficient D. While the D showed the broadband diffusive scattering, the G values indicated the narrowband strong scattering. We note that in deriving Fokker-Planck equation and diffusion coefficient D, we use the

  10. Early Size Distributions of Chondrule Subgroups Overprinted by the Final Accumulation Process of Particle Components in Allende

    NASA Technical Reports Server (NTRS)

    McCain, K. A.; Simon, J. I.; Cuzzi, J. N

    2015-01-01

    Populations of compositionally distinct particles are fundamental components of undifferentiated chondritic meteorites. Many theories explain the formation of chondrites, one class of which includes mechanisms for sorting the component particles in the solar nebula prior to their accretion. Mechanisms include sorting by mass, turbulent concentration, X-winds, and photophoresis, which will produce characteristic distributions of observable properties such as particle size. Distinguishing processes that occur in specific astrophysical environments requires characterization of particle types, which include refractory Ca-Al-rich Inclusions (CAIs) and less-refractory chondrules. Previous investigations of modal abundances of CAIs and chondrules exist, but differences within and between these two groups, both of which are made up of diverse subgroups with different thermal histories and chemical compositions, remain mostly unstudied. The presence of rims, a significant event occurring after the formation of at least some chondrules, have also yet to be considered with respect to sorting. Here we present the sizes of CAIs and chondrules in Allende with attention to the smallest sizes, subgroups, and particle rims.

  11. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative channel coding scheme called 'Accumulate Repeat Accumulate codes' (ARA). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes, thus belief propagation can be used for iterative decoding of ARA codes on a graph. The structure of encoder for this class can be viewed as precoded Repeat Accumulate (RA) code or as precoded Irregular Repeat Accumulate (IRA) code, where simply an accumulator is chosen as a precoder. Thus ARA codes have simple, and very fast encoder structure when they representing LDPC codes. Based on density evolution for LDPC codes through some examples for ARA codes, we show that for maximum variable node degree 5 a minimum bit SNR as low as 0.08 dB from channel capacity for rate 1/2 can be achieved as the block size goes to infinity. Thus based on fixed low maximum variable node degree, its threshold outperforms not only the RA and IRA codes but also the best known LDPC codes with the dame maximum node degree. Furthermore by puncturing the accumulators any desired high rate codes close to code rate 1 can be obtained with thresholds that stay close to the channel capacity thresholds uniformly. Iterative decoding simulation results are provided. The ARA codes also have projected graph or protograph representation that allows for high speed decoder implementation.

  12. Excitation of gap modes in a metal particle-surface system for sub-30 nm plasmonic lithography.

    PubMed

    Murukeshan, Vadakke Matham; Sreekanth, Kandammathe Valiyaveedu

    2009-03-15

    In this Letter, a near-field optical excitation of gap modes in a metal particle-surface system for patterning periodic nanostructure is proposed and numerically demonstrated using the finite-difference time-domain method. It is observed that high-density sub-30 nm periodic structures were achievable by employing an aluminium nanosphere-silver surface system. A 2D resist profile cross section using the modified cellular automata model, which was obtained through this proposed configuration, is also presented. PMID:19282952

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

    SciTech Connect

    Walton, C. D.; Cockcroft, S.; Metheringham, W. J.

    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.

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

    SciTech Connect

    Battaglia, D. J.; Boedo, J. A.; Burrell, K. H.; Chang, C. S.; Canik, J. M.; deGrassie, J. S.; Gerhardt, S. P.; Grierson, B. A.; Groebner, R. J.; Maingi, Rajesh; Smith, S. P.

    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.

  15. Destabilization of the shear Alfven mode by alpha particles and other high energy ions

    NASA Astrophysics Data System (ADS)

    Belikov, V. S.; Kolesnichenko, Ya. I.; Silivra, O. A.

    1992-08-01

    Toroidal Alfven eigenmode (TAE) and elliptical Alfven eigenmode (EAE) instabilities in plasmas with high energy ions are considered in the context of local theory. The instability growth rate is found for cases when waves are excited by alpha particles or by ions produced as a result of neutral injection or RF heating. Electron and ion Landau damping due to the toroidal sideband wave-particle interaction is also calculated. The electron damping rate is shown to be much lower than the generally accepted value. The TAE instability observed in the experiment with neutral beam injection on TFTR is analysed and the principal experimental features of TAE instability are explained

  16. [Remote sensing inversion mode of suspended particles concentration in Hangzhou Bay based on in situ measurement spectrum].

    PubMed

    Wang, Fan; Zhou, Bin; Xu, Jian-Ming; Ling, Zai-Ying

    2008-11-01

    Suspended particles are one of major parameters of coastal water color remote sensing in China. The reflectances spectral of water were measured using an ASD field spectroscope, synchronously the suspended particles concentrations of surface water were acquired in Hangzhou Bay. Two remote sensing inversion models for suspended particles concentrations (SPC) were developed based on t hesimulated reflectance of MODIS & MERIS channels using artificial neural network (ANN) algorithm. Measurement results show that the total SPC of Hangzhou bay is comparatively high where the suspended sediments concentrations (SSC) are far more than chlorophyll concentrations, averagely 705 mg/L and 1.164 mg/m3, reseparately. The SPC in two measurement stations appears spatio-temporal variation, especially the short period change due to tidal cycle. There are two reflectance peaks in the measured spectral curves, one is between 650 nm to 750 nm, and the other is near 800 nm. The first order derivative curves of reflectance spectral indicate that the first reflectance peaks shift to long wavelength according to the increased SSC. The ANN models make full use of the spectral information in different channels which can simulate the pigment and non-pigment particles concentrations at same time. The fitting effects are preferable with R2 more than 0.95 for each model. The ANN mode can be used for satellite remote sensing inversion, especially MERIS data, because of its comparatively high spatial resolution. PMID:19186796

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

    NASA Astrophysics Data System (ADS)

    Diehl, K.; Debertshäuser, M.; Eppers, O.; Schmithüsen, H.; Mitra, S. K.; Borrmann, S.

    2014-05-01

    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{{μ}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.

  18. Interpretation of the I-Regime and transport associated with relevant heavy particle modes

    SciTech Connect

    Coppi, B.; Zhou, T.

    2012-01-15

    The excitation of a novel kind of heavy particle [B. Coppi et al., Phys. Rev. Lett. 17, 377 (1966); B. Coppi and T. Zhou, MIT(LNS) Report HEP 09/04, 2009, Cambridge, MA [Phys. Lett. A 375, 2916 (2011)

  19. Harmonically mode-locked femtosecond fiber laser using non-uniform, WS2-particle deposited side-polished fiber

    NASA Astrophysics Data System (ADS)

    Lee, Junsu; Park, June; Koo, Joonhoi; Jhon, Young Min; Lee, Ju Han

    2016-03-01

    We investigated the feasibility of using a WS2-deposited side-polished fiber as a harmonic mode-locker to produce a femtosecond fiber laser with a frequency of 1.51 GHz. Our work focuses on using a side-polished fiber platform with non-uniform WS2 particles prepared through liquid phase exfoliation method without centrifugation. Femtosecond optical pulses were generated from an all-fiberized erbium-doped fiber-based ring cavity by increasing the pump power to achieve a tunable pulse repetition rate from 14.57 MHz to 1.51 GHz (104th harmonic). The characteristics of the output pulse were systematically investigated to analyze the pulse repetition rate, harmonic order, average output power, pulse energy, and pulse width as a function of the pump power. The output performance of the laser was compared to that of a laser based on a microfiber-based WS2 film SA described in (Yan et al 2015 Opt. Mater. Express 5 479-89). This experimental demonstration reaffirms that a side-polished fiber is an effective platform to implement an ultrafast harmonic mode-locker, and non-uniform WS2 particles prepared via simple liquid phase exfoliation method without centrifugation provide a suitable saturable absorption response at 1.55 μm.

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

    PubMed Central

    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

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    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.

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

    PubMed

    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

  3. Three-dimensional particle trajectories and waste beam losses in injection dump beam line of SNS accumulator ring

    SciTech Connect

    Wang, Jian-Guang; Plum, Michael A

    2008-01-01

    The SNS ring injection dump beam line has been suffering high beam losses since its commissioning. In order to understand the mechanisms of the beam losses, we have performed 3D simulation studies of the beam line. The 3D models consist of three injection chicane dipoles and one injection dump septum magnet. 3D particle trajectories in the models are computed. We then extend particle optics calculations to the injection dump. Our studies have clearly shown some design and operation problems, that cause beam losses in the injection dump beam line. These include incorrect chicane dipole settings, incorrect position of a chicane dipole, too small aperture of injection dump septum, and inadequate focusing downstream. This paper reports our findings and the remedies to the injection beam loss problems.

  4. Low Frequency Fishbone Mode Induced by Circulating Particles in Spherical Tori

    SciTech Connect

    Kolesnichenko, Ya.I.; Marchenko, V.S.; White, R.B.

    2001-02-02

    It is found that high beta in low-aspect-ratio tori tends to stabilize the fishbone instability in a plasma with energetic circulating ions. The stabilization results from enhancement of the toroidal drift motion by large Shafranov shift, which makes it difficult to reconcile the condition of considerable energy exchange between the ions and the internal kink perturbation with the condition of the resonant wave-particle interaction.

  5. Gas accumulation in particle-rich suspensions and implications for bubble populations in crystal-rich magma

    NASA Astrophysics Data System (ADS)

    Belien, Isolde B.; Cashman, Katharine V.; Rempel, Alan W.

    2010-08-01

    Gas mobility plays an important role in driving volcanic eruptions and controlling eruption style. The explosivity of an eruption depends, among other factors, on how easily gas can escape from the magma. Many magmatic systems have high concentrations of suspended crystals that inhibit gas migration through the melt. We use suspensions of plastic beads in corn syrup to investigate interactions between rising bubbles and particles. We observe different interaction styles as the ratio ψ of bubble to particle size is varied. Large bubbles (ψ > 1) deform and sometimes break up as they move around particles. Small bubbles (ψ < 1) are frequently trapped within the suspension, increasing the concentration of gas held within the system. We compare our experiments to bubble populations in tephra from Stromboli volcano, Italy. We show that these samples typically have bubbles and crystals of similar sizes and suggest that crystals might play a role in controlling bubble size in this natural system as well as in our experiments. Because small bubbles (ψ < 1) get trapped within the suspension, and can be formed by breakup of larger bubbles, we expect that an increase in gas flux will result in an increase in the population of small bubbles. Changes in bubble number density and vesicularity in tephra erupted during periods of different eruptive intensity may thus provide a way of tracking changes in gas flux through the magma prior to eruption.

  6. Analysis of element accumulation in cell wall attached and intracellular particles of snow algae by EELS and ESI.

    PubMed

    Lütz-Meindl, Ursula; Lütz, Cornelius

    2006-01-01

    Snow algae frequently occur in alpine and polar permanent snow ecosystems and have developed adaptations to their harsh environment, where extreme temperature regimes high irradiation and low nutrient levels prevail. They live in a unique microhabitat, namely the liquid water between snow crystals. The predominant form appears as 'red snow' and in polar environment also 'green snow' frequently occurs. Light microscopy showed that most cells are densely covered by non-biotic particles of so far unknown composition. As snow normally contains very low amounts of nutrients, introduced mainly airborne like dust and precipitation, the inorganic particles at the surface of the snow algae may be important for their survival. By using electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI), we investigated element distribution in ultrathin sections of snow algae from different polar (Svalbard, 5 m a.s.l., 79 degrees N and maritime Antarctic, King George Island, 10 m a.s.l., 62 degrees S) and alpine habitats (2400-3100 m a.s.l. Tyrol) for the present study. It turned out that the main elements of the cell wall attached particles are Si, Al, Fe and O independently from the origin of the snow algae. Interestingly, the same elements were also found in vacuolar compartments inside the cells. These vacuoles contain electron dense granules or crystals and are frequently found to be connected to the cortical cytoplasm. This finding suggests an uptake mechanism of the respective elements by pinocytosis. Co-transport of toxic aluminium together with silicon may be unavoidable as the inorganic nutrient uptake of the snow algae is limited to the thin water layer between the ice crystals. However, formation of insoluble aluminium silicates may serve as detoxification mechanism. PMID:16376553

  7. Modeling the potential influence of particle deposition on the accumulation of organic contaminants by submerged aquatic vegetation.

    PubMed

    Armitage, James M; Franco, Amaya; Gomez, Sonia; Cousins, Ian T

    2008-06-01

    Submerged aquatic vegetation can act as both a mitigating factor(e.g., reducing downstream impacts of pesticides following runoff/spray drift) and mobilizing factor (e.g., remobilization of contaminants from sediments) influencing the fate and distribution of organic contaminants in the environment. Consequently, there has been wide scientific and regulatory interest in assessing the role of these plants in different contamination scenarios. Mechanistic models describing the environmental fate of contaminants in submerged aquatic vegetation are useful tools for interpreting laboratory and field measurements in addition to providing valuable information to risk assessors. In this study, we developed a fugacity-based model to investigate the influence of particle deposition to plant surfaces on the fate and distribution of two substances in small ponds. The main motivation for conducting this study was to address the fact that the potential contribution of this process is not typically considered by many types of models describing contaminant dynamics in submerged aquatic vegetation. For the hydrophobic substance included in this evaluation (lambda-cyhalothrin), model performance was greatly improved by including this process. The model was also applied in a generic context to compare the importance of particle deposition versus directwater uptake as a function of chemical properties (log Kow) and concentration of suspended solids in the water column. The generic application demonstrated that contaminant mass transfer is dominated by particle deposition for chemicals with log Kow greater than approximately 5.5--6 across a wide range of suspended solid concentrations and can be important even for low log Kow substances in some circumstances. Further empirical and modeling studies are recommended to explore this process more comprehensively. PMID:18589965

  8. Accumulation and transport of microbial-size particles in a pressure protected model burn unit: CFD simulations and experimental evidence

    PubMed Central

    2011-01-01

    Background Controlling airborne contamination is of major importance in burn units because of the high susceptibility of burned patients to infections and the unique environmental conditions that can accentuate the infection risk. In particular the required elevated temperatures in the patient room can create thermal convection flows which can transport airborne contaminates throughout the unit. In order to estimate this risk and optimize the design of an intensive care room intended to host severely burned patients, we have relied on a computational fluid dynamic methodology (CFD). Methods The study was carried out in 4 steps: i) patient room design, ii) CFD simulations of patient room design to model air flows throughout the patient room, adjacent anterooms and the corridor, iii) construction of a prototype room and subsequent experimental studies to characterize its performance iv) qualitative comparison of the tendencies between CFD prediction and experimental results. The Electricité De France (EDF) open-source software Code_Saturne® (http://www.code-saturne.org) was used and CFD simulations were conducted with an hexahedral mesh containing about 300 000 computational cells. The computational domain included the treatment room and two anterooms including equipment, staff and patient. Experiments with inert aerosol particles followed by time-resolved particle counting were conducted in the prototype room for comparison with the CFD observations. Results We found that thermal convection can create contaminated zones near the ceiling of the room, which can subsequently lead to contaminate transfer in adjacent rooms. Experimental confirmation of these phenomena agreed well with CFD predictions and showed that particles greater than one micron (i.e. bacterial or fungal spore sizes) can be influenced by these thermally induced flows. When the temperature difference between rooms was 7°C, a significant contamination transfer was observed to enter into the positive

  9. Modes of surface premelting in colloidal crystals composed of attractive particles

    NASA Astrophysics Data System (ADS)

    Li, Bo; Wang, Feng; Zhou, Di; Peng, Yi; Ni, Ran; Han, Yilong

    2016-03-01

    Crystal surfaces typically melt into a thin liquid layer at temperatures slightly below the melting point of the crystal. Such surface premelting is prevalent in all classes of solids and is important in a variety of metallurgical, geological and meteorological phenomena. Premelting has been studied using X-ray diffraction and differential scanning calorimetry, but the lack of single-particle resolution makes it hard to elucidate the underlying mechanisms. Colloids are good model systems for studying phase transitions because the thermal motions of individual micrometre-sized particles can be tracked directly using optical microscopy. Here we use colloidal spheres with tunable attractions to form equilibrium crystal–vapour interfaces, and study their surface premelting behaviour at the single-particle level. We find that monolayer colloidal crystals exhibit incomplete premelting at their perimeter, with a constant liquid-layer thickness. In contrast, two- and three-layer crystals exhibit conventional complete melting, with the thickness of the surface liquid diverging as the melting point is approached. The microstructures of the surface liquids differ in certain aspects from what would be predicted by conventional premelting theories. Incomplete premelting in the monolayer crystals is triggered by a bulk isostructural solid–solid transition and truncated by a mechanical instability that separately induces homogeneous melting within the bulk. This finding is in contrast to the conventional assumption that two-dimensional crystals melt heterogeneously from their free surfaces (that is, at the solid–vapour interface). The unexpected bulk melting that we observe for the monolayer crystals is accompanied by the formation of grain boundaries, which supports a previously proposed grain-boundary-mediated two-dimensional melting theory. The observed interplay between surface premelting, bulk melting and solid–solid transitions challenges existing theories of

  10. Particle-hole symmetry, many-body localization, and topological edge modes

    NASA Astrophysics Data System (ADS)

    Vasseur, Romain; Friedman, Aaron J.; Parameswaran, S. A.; Potter, Andrew C.

    We study the excited states of interacting fermions in one dimension with particle-hole symmetric disorder (equivalently, random-bond XXZ chains) using a combination of renormalization group methods and exact diagonalization. Absent interactions, the entire many-body spectrum exhibits infinite-randomness quantum critical behavior with highly degenerate excited states. We show that though interactions are an irrelevant perturbation in the ground state, they drastically affect the structure of excited states: even arbitrarily weak interactions split the degeneracies in favor of thermalization (weak disorder) or spontaneously broken particle-hole symmetry, driving the system into a many-body localized spin glass phase (strong disorder). In both cases, the quantum critical properties of the non-interacting model are destroyed, either by thermal decoherence or spontaneous symmetry breaking. This system then has the interesting and counterintuitive property that edges of the many-body spectrum are less localized than the center of the spectrum. We argue that our results rule out the existence of certain excited state symmetry-protected topological orders. Supported by the Gordon and Betty Moore Foundation's EPiQS Initiative (Grant GBMF4307 (ACP), the Quantum Materials Program at LBNL (RV), NSF Grant DMR-1455366 and UCOP Research Catalyst Award No. CA-15-327861 (SAP).

  11. Particle-hole symmetry, many-body localization, and topological edge modes

    NASA Astrophysics Data System (ADS)

    Vasseur, Romain; Friedman, Aaron J.; Parameswaran, S. A.; Potter, Andrew C.

    2016-04-01

    We study the excited states of interacting fermions in one dimension with particle-hole symmetric disorder (equivalently, random-bond XXZ chains) using a combination of renormalization group methods and exact diagonalization. Absent interactions, the entire many-body spectrum exhibits infinite-randomness quantum critical behavior with highly degenerate excited states. We show that though interactions are an irrelevant perturbation in the ground state, they drastically affect the structure of excited states: Even arbitrarily weak interactions split the degeneracies in favor of thermalization (weak disorder) or spontaneously broken particle-hole symmetry, driving the system into a many-body localized spin glass phase (strong disorder). In both cases, the quantum critical properties of the noninteracting model are destroyed, either by thermal decoherence or spontaneous symmetry breaking. This system then has the interesting and counterintuitive property that edges of the many-body spectrum are less localized than the center of the spectrum. We argue that our results rule out the existence of certain excited state symmetry-protected topological orders.

  12. Tests for parity and charge conjugation-parity symmetries of particles by sequential decay modes

    SciTech Connect

    Dell'Aquila, J.R.

    1987-01-01

    We first review the standard model, the symmetries P, C, T, and CP, and the history of parity/signature tests. We proceed to obtain the decay correlation function I({theta}{sub 1}, {theta}{sub 2}, {phi}) and its integrated distributions for sequential decays X {yields} V{sub 1}V{sub 2}, where each V is a vector boson, and at least one of these vector bosons decay to final state pairs containing fermions of spin 1/2, specifically, leptons and quarks. We make fundamental symmetry determinations of the P or CP eigen-values of X from the decay modes JJ, {Upsilon}{Upsilon}, Z{sup 0}Z{sup 0} and W{sup +}W{sup {minus}}, {Phi}J, J{Upsilon}, {Phi}Z{sup 0}JZ{sup 0}, gZ{sup 0}, and gg, where g = gluon jet. This includes tests to distinguish between a spin 0 technipion and an elementary Higgs boson. These symmetry determinations require an accurate measurement of the coefficient of cos2{phi} in the azimuthal distribution for decay modes {Phi}J, JJ, Y Y, {Phi}Z{sup 0}, JZ{sup 0}, Z{sup 0}Z{sup 0}, W{sup +}W{sup {minus}} where the vector bosons other than {Phi} decay into l{sub A}l{sub B} and/or q{sub Z}q{sub B}. Simple tests for CP or P violation by sequential decays are given next.

  13. Tree bark suber-included particles: A long-term accumulation site for elements of atmospheric origin

    NASA Astrophysics Data System (ADS)

    Catinon, Mickaël; Ayrault, Sophie; Spadini, Lorenzo; Boudouma, Omar; Asta, Juliette; Tissut, Michel; Ravanel, Patrick

    2011-02-01

    The deposition of atmospheric elements on and into the bark of 4-year-old Fraxinus excelsior L. was studied. The elemental composition of the suber tissue was established through ICP-MS analysis and the presence of solid mineral particles included in this suber was established and described through SEM-EDX. Fractionation of the suber elements mixture was obtained after ashing at 550 °C through successive water (C fraction) and HNO 3 2 M (D fraction) extraction, leading to an insoluble residue mainly composed of the solid mineral particles (E fraction). The triplicated % weight of C, D and E were respectively 34.4 ± 2.7, 64.8 ± 2.7 and 0.8 ± 0.1% of the suber ashes weight. The main component of C was K, of D was Ca. Noticeable amounts of Mg were also observed in D. The E fraction, composed of insoluble particles, was mostly constituted of geogenic products, with elements such as Si, Al, K, Mg, representing primary minerals. E also contained Ca 3(PO 4) 2 and concentrated the main part of Pb and Fe. Moreover, The SEM-EDX analysis evidenced that this fraction also concentrated several types of fly ashes of industrial origin. The study of the distribution between C, D and E was analysed through ICP-MS with respect to their origin. The origin of the elements found in such bark was either geogenic (clay, micas, quartz…), anthropogenic or biogenic (for instance large amounts of solid Ca organic salts having a storage role). As opposed to the E fraction, the C fraction, mainly composed of highly soluble K+ is characteristic of a biological pool of plant origin. In fraction D, the very high amount of Ca++ corresponds to two different origins: biological or acid soluble minerals such as calcite. Furthermore, the D fraction contains the most part of pollutants of anthropic origin such as Zn, Cu, Ni, Co, Cd. As a whole, the fractionation procedure of the suber samples allows to separate elements as a function of their origin but also gives valuable information on

  14. Bell's experiment with intra- and inter-pair entanglement: Single-particle mode entanglement as a case study

    SciTech Connect

    Ashhab, S.; Nori, Franco; Maruyama, Koji; Brukner, Caslav

    2009-12-15

    Theoretical considerations of Bell-inequality experiments usually assume identically prepared and independent pairs of particles. Here we consider pairs that exhibit both intrapair and interpair entanglement. The pairs are taken from a large many-body system where all the pairs are generally entangled with each other. Using an explicit example based on single mode entanglement and an ancillary Bose-Einstein condensate, we show that the Bell-inequality violation in such systems can display statistical properties that are remarkably different from those obtained using identically prepared independent pairs. In particular, one can have probabilistic violation of Bell's inequalities in which a finite fraction of all the runs result in violation even though there could be no violation when averaging over all the runs. Whether or not a particular run of results will end up being local realistically explainable is 'decided' by a sequence of quantum (random) outcomes.

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

    NASA Astrophysics Data System (ADS)

    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).

  16. [Characterization of ultrafine particle size distribution in the urban atmosphere of Hangzhou in spring].

    PubMed

    Xie, Xiao-Fang; Sun, Zai; Yang, Wen-Jun

    2014-02-01

    Continuous measurement and analysis of the atmospheric ultrafine particle number concentration were performed in Hangzhou from March to May, 2012 by using the fast mobility particle sizer (FMPS). The result showed that daily number concentration of nucleation mode (5.6-20 nm), Aitken mode (20-100 nm), and accumulation mode (100-560 nm) particles, and total particles were 0.84 x 10(4), 1.08 x 10(4), 0.47 x 10(4) and 2.38 x 10(4) cm(-3) respectively. The concentration of Aitken mode particles was higher than that of other mode particles in sunny day. The nucleation mode and Aitken mode particles usually started to increase around 10:00-11:00 and ended up after 3-4 h. This indicated the solar radiation promoted the formation of new particles. Human activities caused the concentration distribution of each mode particles having an obvious difference between workdays and weekends. Combined with the meteorological factors, analysis showed that the wind speed and wind direction also directly influenced particulate concentration. The analysis of particulate concentration and visibility showed that the concentration of accumulation mode particles had a negative relationship with the atmospheric visibility, while those of nucleation mode and Aitken mode particles had a slight influence on it. PMID:24812930

  17. Influence of the ambient humidity on the concentration of natural deposition-mode ice-nucleating particles

    NASA Astrophysics Data System (ADS)

    López, M. L.; Ávila, E. E.

    2016-01-01

    This study reports measurements of deposition-mode ice-nucleating particle (INP) concentrations at ground level during the period July-December 2014 in Córdoba, Argentina. Ambient air was sampled into a cloud chamber where the INP concentration was measured at a temperature of -25 °C and a 15 % supersaturation over ice. Measurements were performed on days with different thermodynamic conditions, including rainy days. The effect of the relative humidity at ground level (RHamb) on the INP concentration was analyzed. The number of INPs activated varied from 1 L-1 at RHamb of 25 % to 30 L-1 at RHamb of 90 %. In general, a linear trend between the INP concentration and the RHamb was found, suggesting that this variability must be related to the effectiveness of the aerosols acting as INPs. From the backward trajectories analysis, it was found that the link between INP concentration and RHamb is independent of the origin of the air masses. The role of biological INPs and nucleation occurring in pores and cavities was discussed as a possible mechanism to explain the increase of the INP concentration during high ambient relative humidity events. This work provides valuable measurements of deposition-mode INP concentrations from the Southern Hemisphere where INP data are sparse so far.

  18. Single particle ICP-MS method development for the determination of plant uptake and accumulation of CeO2 nanoparticles.

    PubMed

    Dan, Yongbo; Ma, Xingmao; Zhang, Weilan; Liu, Kun; Stephan, Chady; Shi, Honglan

    2016-07-01

    Cerium dioxide nanoparticles (CeO2NPs) are among the most broadly used engineered nanoparticles that will be increasingly released into the environment. Thus, understanding their uptake, transportation, and transformation in plants, especially food crops, is critical because it represents a potential pathway for human consumption. One of the primary challenges for the endeavor is the inadequacy of current analytical methodologies to characterize and quantify the nanomaterial in complex biological samples at environmentally relevant concentrations. Herein, a method was developed using single particle-inductively coupled plasma-mass spectrometry (SP-ICP-MS) technology to simultaneously detect the size and size distribution of particulate Ce, particle concentration, and dissolved cerium in the shoots of four plant species including cucumber, tomato, soybean, and pumpkin. An enzymatic digestion method with Macerozyme R-10 enzyme previously used for gold nanoparticle extraction from the tomato plant was adapted successfully for CeO2NP extraction from all four plant species. This study is the first to report and demonstrate the presence of dissolved cerium in plant seedling shoots exposed to CeO2NPs hydroponically. The extent of plant uptake and accumulation appears to be dependent on the plant species, requiring further systematic investigation of the mechanisms. PMID:27129977

  19. Profile distribution and accumulation characteristics of organic carbon in a karst hillslope based on particle-size fractionation and stable isotope analysis.

    PubMed

    Liu, Taoze; Zhao, Zhiqi; Lang, Yunchao; Ding, Hu

    2015-07-01

    Recent studies have highlighted tight coupling between soil aggregate fractions and soil organic carbon (SOC) turnover. However, large uncertainties remain and a mechanistic understanding of geomorphic and land use change effects on carbon storage in soil is still lacking. Taking typical slope of vegetation recovery in karst area as object, the present study analyzed organic carbon content and stable carbon isotope composition (δ13C value) of soil organic matter in bulk and particle size separates of soil on profiles at different topographic positions. The results showed that SOC content decreased gradually in downhill direction. Organic carbon content of sandy soil (50-2000 μm) accounted above 50% in the upper slope positions but in the middle and lower slope soil profiles, organic carbon was mainly stored in silts (2-50 μm) and clays (< 2 μm) which belonged to stable and highly humified SOC. The composition difference of δ13C values in soil profiles reflected the input of plant residues and accumulation characteristics. Organic matter was deposited in different soil particle sizes owing to different degrees of decomposition. Hence, δ13C value can help in identifying the storage and decomposition rates of soil organic matter. PMID:26387345

  20. Accumulate-Repeat-Accumulate-Accumulate-Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Thorpe, Jeremy

    2004-01-01

    Inspired by recently proposed Accumulate-Repeat-Accumulate (ARA) codes [15], in this paper we propose a channel coding scheme called Accumulate-Repeat-Accumulate-Accumulate (ARAA) codes. These codes can be seen as serial turbo-like codes or as a subclass of Low Density Parity Check (LDPC) codes, and they have a projected graph or protograph representation; this allows for a high-speed iterative decoder implementation using belief propagation. An ARAA code can be viewed as a precoded Repeat-and-Accumulate (RA) code with puncturing in concatenation with another accumulator, where simply an accumulator is chosen as the precoder; thus ARAA codes have a very fast encoder structure. Using density evolution on their associated protographs, we find examples of rate-lJ2 ARAA codes with maximum variable node degree 4 for which a minimum bit-SNR as low as 0.21 dB from the channel capacity limit can be achieved as the block size goes to infinity. Such a low threshold cannot be achieved by RA or Irregular RA (IRA) or unstructured irregular LDPC codes with the same constraint on the maximum variable node degree. Furthermore by puncturing the accumulators we can construct families of higher rate ARAA codes with thresholds that stay close to their respective channel capacity thresholds uniformly. Iterative decoding simulation results show comparable performance with the best-known LDPC codes but with very low error floor even at moderate block sizes.

  1. Flux and accumulation of sedimentary particles off the continental slope of Pakistan: a comparison of water column and seafloor estimates from the oxygen minimum zone, NE Arabian Sea

    NASA Astrophysics Data System (ADS)

    Schulz, H.; von Rad, U.

    2013-07-01

    Due to the lack of bioturbation, the laminated muds from the oxygen-minimum zone (OMZ) off Pakistan provide a unique opportunity to precisely determine the vertical and lateral sediment fluxes in the near shore part of the northeastern Arabian Sea, and to explore the effects of the margin topography and the low oxygen conditions on the accumulation of organic matter and other particles. West of Karachi, in the Hab river area of EPT and WPT (Eastern and Western PAKOMIN Traps), 16 short sediment profiles from water depths between 250 m and 1970 m on a depth transect crossing the OMZ (~ 120 to ~ 1200 m water depth) were investigated, and correlated on the basis of a thick, light-gray- to reddish-colored turbidite layer. Varve counting yielded a date for this layer of AD 1905 to 1888. We adopted the young age which agrees with 210Pb- dating, and used this isochronous stratigraphic marker bed to calculate sediment accumulation rates, that we could directly compare with the flux rates from the sediment traps installed within the water column above. All traps in the area show exceptionally high, pulsed winter fluxes of up to 5000 mg m-2 d-1 in this margin environment. The lithic flux at the sea floor is as high as 4000 mg m-2 d-1 , and agrees remarkably well with the bulk winter flux of material. This holds as well for the individual bulk components (organic carbon, calcium carbonate, opal, lithic fraction). However, the high winter flux events (HFE) by their extreme mass of remobilized matter terminated the recording in the shallow traps by clogging the funnels. Based on our comparisons, we argue that HFE for the past 5000 yr most likely occurred as regular events within the upper OMZ off Pakistan. Coarse fraction and foraminiferal accumulation rates from sediment surface samples along the Hab transect show distribution patterns that seem to be a function of water depth and distance from the shelf. Some of these sediment fractions show sudden shifts at the lower boundary

  2. Electrostatic transport in L-mode scrape-off layer plasmas in the Tore Supra tokamak. I. Particle balance

    SciTech Connect

    Fedorczak, N.; Gunn, J. P.; Pascal, J.-Y.; Ghendrih, Ph.; Monier-Garbet, P.; Marandet, Y.

    2012-07-15

    Particle balance is investigated using a Mach probe at the top of the scrape-off layer of circular ohmically heated L-mode plasmas in the Tore Supra tokamak [G. Giruzzi etal., Nucl. Fusion 49, 104010 (2009)]. Contributions from both poloidal EXB flows and ionization sources are found to be small. As a result the local parallel flow is a response of the radial flux distribution between the two strike points of open field lines, and the density profile is determined by the field-line-integrated radial flux. By scanning the poloidal position of the strike point on a secondary limiter situated at the outboard midplane, an indirect poloidal mapping of the radial flux distribution is obtained. The radial flux is centered at the outboard midplane and is relatively well described by a Gaussian distribution of half poloidal width of about 50 Degree-Sign at the last closed flux surface, decaying to about 30 Degree-Sign in the far scrape-off layer. The turbulent radial flux measured locally with a rake probe shows a reasonable agreement with the poloidal mapping obtained by the Mach probe. It is shown than the radial convective velocity decays along radius at the plasma top but should increase with radius at the outboard midplane.

  3. Accumulate-Repeat-Accumulate-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Samuel; Thorpe, Jeremy

    2007-01-01

    Accumulate-repeat-accumulate-accumulate (ARAA) codes have been proposed, inspired by the recently proposed accumulate-repeat-accumulate (ARA) codes. These are error-correcting codes suitable for use in a variety of wireless data-communication systems that include noisy channels. ARAA codes can be regarded as serial turbolike codes or as a subclass of low-density parity-check (LDPC) codes, and, like ARA codes they have projected graph or protograph representations; these characteristics make it possible to design high-speed iterative decoders that utilize belief-propagation algorithms. The objective in proposing ARAA codes as a subclass of ARA codes was to enhance the error-floor performance of ARA codes while maintaining simple encoding structures and low maximum variable node degree.

  4. The role of the equatorial ligands for the redox behavior, mode of cellular accumulation and cytotoxicity of platinum(IV) prodrugs.

    PubMed

    Göschl, Simone; Varbanov, Hristo P; Theiner, Sarah; Jakupec, Michael A; Galanski, Markus; Keppler, Bernhard K

    2016-07-01

    The current study aims to elucidate the possible reasons for the significantly different pharmacological behavior of platinum(IV) complexes with cisplatin-, carboplatin- or nedaplatin-like cores and how this difference can be related to their main physicochemical properties. Chlorido-containing complexes are reduced fast (within hours) by ascorbate and are able to unwind plasmid DNA in the presence of ascorbate, while their tri- and tetracarboxylato analogs are generally inert under the same conditions. Comparison of the lipophilicity, cellular accumulation and cytotoxicity of the investigated platinum compounds revealed the necessity to define new structure-property/activity relationships (SPRs and SARs). The higher activity and improved accumulation of platinum(IV) complexes bearing Cl(-) in equatorial position cannot only be attributed to passive diffusion facilitated by their lipophilicity. Therefore, further platinum accumulation experiments under conditions where active/facilitated transport mechanisms are suppressed were performed. Under hypothermic conditions (4°C), accumulation of dichloridoplatinum(IV) complexes is reduced down to 10% of the amount determined at 37°C. These findings suggest the involvement of active and/or facilitated transport in cellular uptake of platinum(IV) complexes with a cisplatin-like core. Studies with ATP depletion mediated by oligomycin and low glucose partially confirmed these observations, but their feasibility was severely limited in the adherent cell culture setting. PMID:27055943

  5. Detectors for alpha particles and X-rays operating in ambient air in pulse counting mode or/and with gas amplification

    NASA Astrophysics Data System (ADS)

    Charpak, G.; Benaben, P.; Breuil, P.; Peskov, V.

    2008-02-01

    Ionization chambers working in ambient air in current detection mode are attractive due to their simplicity and low cost and are widely used in several applications such as smoke detection, dosimetry, therapeutic beam monitoring and so on. The aim of this work was to investigate if gaseous detectors can operate in ambient air in pulse counting mode as well as with gas amplification which potentially offers the highest possible sensitivity in applications like alpha particle detection or high energy X-ray photon or electron detection. To investigate the feasibility of this method two types of open- end gaseous detectors were build and successfully tested. The first one was a single wire or multiwire cylindrical geometry detector operating in pulse mode at a gas gain of one (pulse ionization chamber). This detector was readout by a custom made wide -band charge sensitive amplifier able to deal with slow induced signals generated by slow motion of negative and positive ions. The multiwire detector was able to detect alpha particles with an efficiency close to 22%. The second type of an alpha detector was an innovative GEM-like detector with resistive electrodes operating in air in avalanche mode at high gas gains (up to 104). This detector can also operate in a cascaded mode or being combined with other detectors, for example with MICROMEGAS. This detector was readout by a conventional charge -sensitive amplifier and was able to detect alpha particles with 100% efficiency. This detector could also detect X-ray photons or fast electrons. A detailed comparison between these two detectors is given as well as a comparison with commercially available alpha detectors. The main advantages of gaseous detectors operating in air in a pulse detection mode are their simplicity, low cost and high sensitivity. One of the possible applications of these new detectors is alpha particle background monitors which, due to their low cost can find wide application not only in houses, but

  6. Optimization of the Mode of the Uranium-233 Accumulation for Application in Thorium Self-Sufficient Fuel Cycle of Candu Power Reactor

    SciTech Connect

    Bergelson, Boris; Gerasimov, Alexander; Tikhomirov, Georgy

    2006-07-01

    Results of calculation studies of the first stage of self-sufficient thorium cycle for CANDU reactor are presented in the paper. The first stage is preliminary accumulation of {sup 233}U in the CANDU reactor itself. Parameters of active core and scheme of fuel reloading were accepted the same as those for CANDU reactor. It was assumed for calculations, that enriched {sup 235}U or plutonium was used as additional fissile material to provide neutrons for {sup 233}U production. Parameters of 10 different variants of the elementary cell of active core were calculated for the lattice pitch, geometry of fuel channels, and fuel assembly of the CANDU reactor. The results presented in the paper allow to determine the time of accumulation of the required amount of {sup 233}U and corresponding number of targets going into processing for {sup 233}U extraction. Optimum ratio of the accumulation time to number of processed targets can be determined using the cost of electric power produced by the reactor and cost of targets along with their processing. (authors)

  7. Dynamic mode decomposition of separated flow over a finite blunt plate: time-resolved particle image velocimetry measurements

    NASA Astrophysics Data System (ADS)

    Liu, Yingzheng; Zhang, Qingshan

    2015-07-01

    Dynamic mode decomposition (DMD) analysis was performed on a large number of realizations of the separated flow around a finite blunt plate, which were determined by using planar time-resolved particle image velocimetry (TR-PIV). Three plates with different chord-to-thickness ratios corresponding to globally different flow patterns were particularly selected for comparison: L/D = 3.0, 6.0 and 9.0. The main attention was placed on dynamic variations in the dominant events and their interactive influences on the global fluid flow in terms of the DMD analysis. Toward this end, a real-time data transfer from the high-speed camera to the arrayed disks was built to enable continuous sampling of the spatiotemporally varying flows at the frequency of 250 Hz for a long run. The spectra of the wall-normal velocity fluctuation, the energy spectra of the DMD modes, and their spatial patterns convincingly determined the energetic unsteady events, i.e., St = 0.051 (Karman vortex street), 0.109 (harmonic event of Karman vortex street) and 0.197 (leading-edge vortex) in the shortest system L/D = 3.0, St = 0.159 (Karman vortex street) and 0.242 (leading-edge vortex) in the system L/D = 6.0, and St = 0.156 (Karman vortex street) and 0.241 (leading-edge vortex) in the longest system L/D = 9.0. In the shortest system L/D = 3.0, the first DMD mode pattern demonstrated intensified entrainment of the massive fluid above and below the whole plate by the Karman vortex street. The phase-dependent variation in the low-order flow field elucidated that this motion was sustained by the consecutive mechanisms of the convective leading-edge vortices near the upper and lower trailing edges, and the large-scale vortical structures occurring immediately behind the trailing edge, whereas the leading-edge vortices were entrained and decayed into the near wake. For the system L/D = 6.0, the closely approximated energy spectra at St = 0.159 and 0.242 indicated the balanced dominance of dual unsteady

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

    ERIC Educational Resources Information Center

    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…

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

    NASA Astrophysics Data System (ADS)

    Liu, Dongjian; Bao, Jian; Han, Tao; Wang, Jiaqi; Lin, Zhihong

    2016-02-01

    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 De2, where De is the electron skin depth. On the other hand, the growth rate of a double tearing mode is proportional to De in the parameter regime of fusion plasmas.

  10. Airborne Coarse Mode Aerosol Measurements with the CAS-DPOL Instrument: Effects of Particle Shape and Refractive Index and Implications for Radiative Transfer Estimate

    NASA Astrophysics Data System (ADS)

    Sauer, D. N.; Weinzierl, B.; Gasteiger, J.; Spanu, A.; Freudenthaler, V.; Gross, S.

    2015-12-01

    Each year huge amounts of mineral dust are mobilized in deserts and arid regions of the world and transported over large distances forming thick elevated aerosol layers with a substantial fraction of coarse mode particles. Optical properties of mineral dust, including the absorptive refractive index of some components, cause a significant effect on the atmospheric radiative energy balance from optical to infrared wavelengths. The aerosol characteristics, in particular its coarse mode size distribution, are modified during long-range transport by aging and deposition processes. This also affects the aerosol optical properties and therefore the effect on the atmospheric radiative energy budget. In-situ measurements of aerosol microphysical properties are essential to characterize those effects in order to be implemented in global climate models in parametrized form. However, in-situ measurements of airborne coarse mode aerosols such as mineral dust and volcanic ash are challenging and the measurements are usually affected by substantial uncertainties. In this work we use airborne measurements of mineral dust from our optical light-scattering spectrometer CAS-DPOL during SALTRACE 2013 to discuss the analysis of such data. We cover the effects of varying refractive index and particle shapes and develop recommendations for the configuration of the CAS-DPOL for aerosol studies. We also present an inversion method to derive coarse mode size distributions from light-scattering probes for mixtures of non-spherical, absorbing aerosols. The size distributions retrieved from the in-situ measurements are then validated using an independent analysis with a combination of sun-photometer and lidar data. We apply these methods to investigate the Saharan mineral dust particle size distributions measured on both sides of the Atlantic Ocean and discuss the influence of aerosol aging on the atmospheric radiative energy budget. With this example we also assess how the uncertainties

  11. Radial Transport Characteristics of Fast Ions Due to Energetic-Particle Modes inside the Last Closed-Flux Surface in the Compact Helical System

    SciTech Connect

    Nagaoka, Kenichi; Isobe, Mitsutaka; Toi, Kazuo; Shimizu, Akihiro; Fujisawa, Akihide; Ohshima, Shunsuke; Nakano, Haruhisa; Osakabe, Masaki; Todo, Yasushi; Akiyama, Tsuyoshi; Suzuki, Chihiro; Nishimura, Shin; Yoshimura, Yasuo; Matsuoka, Keisuke; Okamura, Shoichi; Nagashima, Yoshihiko

    2008-02-15

    The internal behavior of fast ions interacting with magnetohydrodynamic bursts excited by energetic ions has been experimentally investigated in the compact helical system. The resonant convective oscillation of fast ions was identified inside the last closed-flux surface during an energetic-particle mode (EPM) burst. The phase difference between the fast-ion oscillation and the EPM, indicating the coupling strength between them, remains a certain value during the EPM burst and drives an anomalous transport of fast ions.

  12. The magnetic particle in a box: Analytic and micromagnetic analysis of probe-localized spin wave modes

    SciTech Connect

    Adur, Rohan Du, Chunhui; Manuilov, Sergei A.; Wang, Hailong; Yang, Fengyuan; Pelekhov, Denis V.; Hammel, P. Chris

    2015-05-07

    The dipole field from a probe magnet can be used to localize a discrete spectrum of standing spin wave modes in a continuous ferromagnetic thin film without lithographic modification to the film. Obtaining the resonance field for a localized mode is not trivial due to the effect of the confined and inhomogeneous magnetization precession. We compare the results of micromagnetic and analytic methods to find the resonance field of localized modes in a ferromagnetic thin film, and investigate the accuracy of these methods by comparing with a numerical minimization technique that assumes Bessel function modes with pinned boundary conditions. We find that the micromagnetic technique, while computationally more intensive, reveals that the true magnetization profiles of localized modes are similar to Bessel functions with gradually decaying dynamic magnetization at the mode edges. We also find that an analytic solution, which is simple to implement and computationally much faster than other methods, accurately describes the resonance field of localized modes when exchange fields are negligible, and demonstrating the accessibility of localized mode analysis.

  13. Simplified models for the nonlinear evolution of two fast-particle-driven modes near the linear stability threshold

    NASA Astrophysics Data System (ADS)

    Galant, Grzegorz; Zaleśny, Jarosław; Lisak, Mietek; Berczyński, Paweł; Berczyński, Stefan

    2011-05-01

    An analytical model that is based on purely differential equations of the nonlinear dynamics of two plasma modes driven resonantly by high-energy ions near the instability threshold is presented here. The well-known integro-differential model of Berk and Breizman (BB) extended to the case of two plasma modes is simplified here to a system of two coupled nonlinear differential equations of fifth order. The effects of the Krook, diffusion and dynamical friction (drag) relaxation processes are considered, whereas shifts in frequency and wavenumber between the modes are neglected. In spite of these simplifications the main features of the dynamics of the two plasma modes are retained. The numerical solutions to the model equations show competition between the two modes for survival, oscillations, chaotic regimes and 'blow-up' behavior, similar to the BB model.

  14. Observation of impurity accumulation and concurrent impurity influx in PBX

    SciTech Connect

    Sesnic, S.S.; Fonck, R.J.; Ida, K.; Bol, K.; Couture, P.; Gammel, G.; Kaita, R.; Kaye, S.; Kugel, H.; LeBlanc, B.

    1986-07-01

    Impurity studies in L- and H-mode discharges in PBX have shown that both types of discharges can evolve into either an impurity accumulative or nonaccumulative case. In a typical accumulative discharge, Zeff peaks in the center to values of about 5. The central metallic densities can be high, n/sub met//n/sub e/ approx. = 0.01, resulting in central radiated power densities in excess of 1 W/cm/sup 3/, consistent with bolometric estimates. The radial profiles of metals obtained independently from the line radiation in the soft x-ray and the VUV regions are very peaked. Concurrent with the peaking, an increase in the impurity influx coming from the edge of the plasma is observed. At the beginning of the accumulation phase the inward particle flux for titanium has values of 6 x 10/sup 10/ and 10 x 10/sup 10/ particles/cm/sup 2/s at minor radii of 6 and 17 cm. At the end of the accumulation phase, this particle flux is strongly increased to values of 3 x 10/sup 12/ and 1 x 10/sup 12/ particles/cm/sup 2/s. This increased flux is mainly due to influx from the edge of the plasma and to a lesser extent due to increased convective transport. Using the measured particle flux, an estimate of the diffusion coefficient D and the convective velocity v is obtained.

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

    NASA Astrophysics Data System (ADS)

    McClenaghan, J.; Lin, Z.; Holod, I.; Deng, W.; Wang, Z.

    2014-12-01

    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.

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

    SciTech Connect

    McClenaghan, J.; Lin, Z.; Holod, I.; Deng, W.; Wang, Z.

    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.

  17. Hygroscopic Fine Mode Particle Deposition on Electronic Circuitsand Resulting Degradation of Circuit Performance: An ExperimentalStudy

    SciTech Connect

    Litvak, Andres; Gadgil, A.; Fisk, W.J.

    1998-03-01

    A portion of electronic equipment failures is a consequenceof particle deposition on electronic circuits in normal indoorenvironments. Deposited hygroscopic particles reduce the electricalisolation (EI) between conductors. In laboratory experiments, weinvestigated the mechanisms, locations, and effects of particledeposition on electronic circuits with surface mounted chips (SMCs) andalso on small television sets. One set of electronics was exposed for 281h to an unusually high concentration of artificially-generated ammoniumsulfate particles while a second set (experimental controls) was exposedto normal indoor particles. The particle mass concentration in thehigh-exposure chamber was 500 times higher than normal. Televisionreliability was observed and the changes in EI between adjacent legs ofSMCs were measured. The experiments demonstrate the strong influence ofelectrostatic forces on the locations and rates of particle deposition.Although televisions did not fail after exposure to concentratedaerosols, the EI between adjacent legs of the SMCs was, in many cases,greatly diminished. Relative humidity had a very strong influence on themagnitude of EI. A qualitative explanation of the mechanisms of particledeposition and circuit degradation is proposed, including the role offibers. Finally, a potential method to reduce particle deposition onelectronic components is discussed.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Measurement of Bulk Velocity and Attenuation in Fluids and Particle Suspensions Using the Quasi-Scholte Mode

    NASA Astrophysics Data System (ADS)

    Cegla, F. B.; Cawley, P.; Lowe, M. J. S.

    2006-03-01

    An alternative method to conventional ultrasonic test cells for fluid bulk property measurements is presented in this paper. An interface wave, called the quasi-Scholte (QS) mode, is used to extract the necessary information. The sensitivity of the quasi-Scholte (QS) mode to the liquid parameters is demonstrated. Experimental measurements of small changes in velocity due to temperature changes and measurements of silica-suspension properties have been successfully carried out using this method. Rapid fluid property measurements in harsh environments are possible. The transducer is separated from the measurement area by the "dipstick", which is inexpensive and portable.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. 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

    NASA Astrophysics Data System (ADS)

    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.

  2. Accumulate Repeat Accumulate Coded Modulation

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative coded modulation scheme called 'Accumulate Repeat Accumulate Coded Modulation' (ARA coded modulation). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes that are combined with high level modulation. Thus at the decoder belief propagation can be used for iterative decoding of ARA coded modulation on a graph, provided a demapper transforms the received in-phase and quadrature samples to reliability of the bits.

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

    NASA Astrophysics Data System (ADS)

    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%.

  4. Airborne Measurements of Coarse Mode Aerosol Composition and Abundance

    NASA Astrophysics Data System (ADS)

    Froyd, K. D.; Murphy, D. M.; Brock, C. A.; Ziemba, L. D.; Anderson, B. E.; Wilson, J. C.

    2015-12-01

    Coarse aerosol particles impact the earth's radiative balance by direct scattering and absorption of light and by promoting cloud formation. Modeling studies suggest that coarse mode mineral dust and sea salt aerosol are the dominant contributors to aerosol optical depth throughout much of the globe. Lab and field studies indicate that larger aerosol particles tend to be more efficient ice nuclei, and recent airborne measurements confirm the dominant role of mineral dust on cirrus cloud formation. However, our ability to simulate coarse mode particle abundance in large scale models is limited by a lack of validating measurements above the earth's surface. We present airborne measurements of coarse mode aerosol abundance and composition over several mid-latitude, sub-tropical, and tropical regions from the boundary layer to the stratosphere. In the free troposphere the coarse mode constitutes 10-50% of the total particulate mass over a wide range of environments. Above North America mineral dust typically dominates the coarse mode, but biomass burning particles and sea salt also contribute. In remote environments coarse mode aerosol mainly consists of internally mixed sulfate-organic particles. Both continental and marine convection can enhance coarse aerosol mass through direct lofting of primary particles and by secondary accumulation of aerosol material through cloud processing.

  5. Ultrafine-Particle Emission Factors as a Function of Vehicle Mode of Operation for LDVs Based on Near-Roadway Monitoring.

    PubMed

    Zhai, Wenjuan; Wen, Dongqi; Xiang, Sheng; Hu, Zhice; Noll, Kenneth E

    2016-01-19

    This paper presents ultrafine-particle (UFP) emission factors (EFs) as a function of vehicle mode of operation (free flow and congestion) using (1) concurrent 5 min measurements of UFPs and carbon monoxide (CO) concentration, wind speed and direction, traffic volume and speed near a roadway that is restricted to light-duty vehicles (LDVs) and (2) inverse dispersion model calculations. Short-term measurements are required to characterize the highly variable and rapidly changing UFP concentration generated by vehicles. Under congestion conditions, the UFP vehicle EFs increased from 0.5 × 10(13) to 2 × 10(13) (particles km(-1) vehicle(-1)) when vehicle flow increased from 5500 to 7500 vehicles/h. For free-flow conditions, the EF is constant at 1.5 × 10(13) (particles km(-1) vehicle(-1)). The analysis is based on the assumption that air-quality models adequately describe the dilution process due to both traffic and atmospheric turbulence. The approach used to verify this assumption was to use an emission factor model to determine EFs for CO and then estimate dilution factors using measured CO concentrations. This procedure eliminates the need to rely only on air quality models to generate dilution factors. The EFs are suitable for fleet emissions under real-world traffic conditions. PMID:26674658

  6. Surface and bulk infrared modes of crystalline and amorphous silica particles: a study of the relation of surface structure to cytotoxicity of respirable silica.

    PubMed Central

    Pandurangi, R S; Seehra, M S; Razzaboni, B L; Bolsaitis, P

    1990-01-01

    Surface IR (infrared) modes of crystalline and fumed (amorphous) silica particles, calcined at temperatures up to 1095 degrees C, have been studied by Fourier transform infrared spectroscopy. The ability of these same particles to lyse cells has been measured by a hemolysis protocol. The untreated crystalline and amorphous materials differ by a factor of 40 in specific surface area, and the intensity per unit mass of the sharp surface silanol band near 3745 cm-1 in the amorphous material is an order of magnitude larger than in the crystalline material. A similar difference is observed in the lysing potential of the two materials. The intensity of the silanol band increases after calcination for both materials, reaching peak values near 500 degrees C, followed by a dramatic drop at higher calcination temperatures, and reaching negligible values for materials calcined near 1100 degrees C. The lysing potential data follow essentially the same pattern for both crystalline and fumed silica. These results are consistent with the hypothesis that the surface silanol groups are involved in cell lysis. Further experiments are suggested to evaluate the relationship between the surface structure of silica particles and their potential cytotoxicity. Images FIGURE 2. A FIGURE 2. B FIGURE 2. C FIGURE 2. D PMID:2169410

  7. Particle surface area dependence of mineral dust in immersion freezing mode: investigations with freely suspended drops in an acoustic levitator and a vertical wind tunnel

    NASA Astrophysics Data System (ADS)

    Diehl, K.; Debertshäuser, M.; Eppers, O.; Schmithüsen, H.; Mitra, S. K.; Borrmann, S.

    2014-11-01

    The heterogeneous freezing temperatures of supercooled drops were measured using an acoustic levitator. This technique allows one to freely suspend single drops in the air without any wall contact. Heterogeneous nucleation by two types of illite (illite IMt1 and illite NX) and a montmorillonite sample was investigated in the immersion mode. Drops of 1 mm in radius were monitored by a video camera while cooled down to -28 °C to simulate freezing within the tropospheric temperature range. The surface temperature of the drops was contact-free, determined with an infrared thermometer; the onset of freezing was indicated by a sudden increase of the drop surface temperature. For comparison, measurements with one particle type (illite NX) were additionally performed in the Mainz vertical wind tunnel with drops of 340 μm radius freely suspended. Immersion freezing was observed in a temperature range between -13 and -26 °C as a function of particle type and particle surface area immersed in the drops. Isothermal experiments in the wind tunnel indicated that after the cooling stage freezing still proceeds, at least during the investigated time period of 30 s. The results were evaluated by applying two descriptions of heterogeneous freezing, the stochastic and the singular model. Although the wind tunnel results do not support the time-independence of the freezing process both models are applicable for comparing the results from the two experimental techniques.

  8. Mode instabilities and dynamic patterns in a colony of self-propelled surfactant particles covering a thin liquid layer.

    PubMed

    Pototsky, Andrey; Thiele, Uwe; Stark, Holger

    2016-05-01

    We consider a colony of point-like self-propelled surfactant particles (swimmers) without direct interactions that cover a thin liquid layer on a solid support. The particles predominantly swim normal to the free film surface with only a small component parallel to the film surface. The coupled dynamics of the swimmer density and film height profile is captured in a long-wave model allowing for diffusive and convective transport of the swimmers (including rotational diffusion). The dynamics of the film height profile is determined by i) the upward pushing force of the swimmers onto the liquid-gas interface, ii) the solutal Marangoni force due to gradients in the swimmer concentration, and iii) the rotational diffusion of the swimmers together with the in-plane active motion. After reviewing and extending the analysis of the linear stability of the uniform state, we analyse the fully nonlinear dynamic equations and show that point-like swimmers, which only interact via long-wave deformations of the liquid film, self-organise in highly regular (standing, travelling, and modulated waves) and various irregular patterns. PMID:27145959

  9. Influence of breathing mode and activity level on the regional deposition of inhaled particles and implications for regulatory standards

    SciTech Connect

    Miller, F.J.; Martonen, T.B.; Menache, M.G.; Spektor, D.M.; Lippmann, M.

    1985-09-01

    Particulate size-selective sampling is an important consideration in determining ambient air quality standards and threshold limit values for workplace exposures. Hazard evaluations, as well as risk analyses, can benefit from an improved understanding of factors affecting regional respiratory tract deposition of particles in man. Here, thoracic deposition and its component parts are examined, as a function of particulate size, for ventilation rates ranging from normal respiration to heavy exercise in individuals who are habitual mouth breathers and in those who normally employ oronasal breathing when minute ventilations exceed approximately 35 1/Lmin. The logistic models yielded significantly improved fits of the experimental data compared to previously used linear regression models. The analyses demonstrate that the activity level of the exposed population should be taken into account to assess the potential health consequences from ambient or workplace exposures.

  10. Possibilities of new generation columns packed with 1.3μm core-shell particles in gradient elution mode.

    PubMed

    Fekete, Szabolcs; Guillarme, Davy

    2013-12-13

    The aim of this work was to evaluate the practical possibilities in gradient elution mode of a column packed with 1.3μm core-shell particles recently released on the market. For this purpose, two types of analytes possessing different diffusion coefficients were selected (small molecule and peptide). It appears that the new 1.3μm material was particularly well suited for fast separations, compared to other existing core-shell particle dimensions in gradient mode. The new material systematically outperforms the other existing ones for peak capacity up to 300 for small molecules and 700 (corresponding to t0=15min) for peptides. Based on these cut-off values, the advantage of column packed with 1.3μm was much more obvious for peptides vs. small molecules analysis. Further improvements in terms of column mechanical stability and system upper pressure capability could expand the limits of separation speed and efficiency to a different level. Again, because of the current pressure limitation and low permeability, a column length of more than 5-8cm is never desired for small molecules analysis in gradient elution. On the contrary, longer columns were useful for peptide analysis. As example, a column of 28cm packed with 1.3μm particles provides a peak capacity of 1000 in the case of peptides analysis. All the predicted values were experimentally confirmed using a standardized extract of Ginkgo biloba and a tryptic digest of a monoclonal antibody (Panitumumab). For the plant extract, the better performance was always achieved with a 5cm long column (P=267 and 268 for the 5 and 15cm, respectively, using a gradient time of 10 and 40min, respectively). Finally, in the case of peptide mapping, a 15cm long column packed with 1.3μm particles was the best choice (P=176 and 311 for the 5 and 15cm, respectively, using a gradient time of 10 and 40min, respectively). PMID:24210304

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Sub-micron particle number size distributions characteristics at an urban location, Kanpur, in the Indo-Gangetic Plain

    NASA Astrophysics Data System (ADS)

    Kanawade, V. P.; Tripathi, S. N.; Bhattu, Deepika; Shamjad, P. M.

    2014-10-01

    We present long-term measurements of sub-micron particle number size distributions (PNSDs) conducted at an urban location, Kanpur, in India, from September 2007 to July 2011. The mean Aitken mode (NAIT), accumulation mode (NACCU), the total particle (NTOT), and black carbon (BC) mass concentrations were 12.4 × 103 cm- 3, 18.9 × 103 cm- 3, 31.9 × 103 cm- 3, and 7.96 μg m- 3, respectively, within the observed range at other urban locations worldwide, but much higher than those reported at urban sites in the developed nations. The total particle volume concentration appears to be dominated mainly by the accumulation mode particles, except during the monsoon months, perhaps due to efficient wet deposition of accumulation mode particles by precipitation. At Kanpur, the diurnal variation of particle number concentrations was very distinct, with highest during morning and late evening hours, and lowest during the afternoon hours. This behavior could be attributed to the large primary emissions of aerosol particles and temporal evolution of the planetary boundary layer. A distinct seasonal variation in the total particle number and BC mass concentrations was observed, with the maximum in winter and minimum during the rainy season, however, the Aitken mode particles did not show a clear seasonal fluctuation. The ratio of Aitken to accumulation mode particles, NAIT/NACCU, was varied from 0.1 to 14.2, with maximum during April to September months, probably suggesting the importance of new particle formation processes and subsequent particle growth. This finding suggests that dedicated long-term measurements of PNSDs (from a few nanometer to one micron) are required to systematically characterize new particle formation over the Indian subcontinent that has been largely unstudied so far. Contrarily, the low NAIT/NACCU during post-monsoon and winter indicated the dominance of biomass/biofuel burning aerosol emissions at this site.

  13. Chronic exposure of tilapia (Oreochromis niloticus) to iron oxide nanoparticles: Effects of particle morphology on accumulation, elimination, hematology and immune responses.

    PubMed

    Ates, Mehmet; Demir, Veysel; Arslan, Zikri; Kaya, Hasan; Yılmaz, Sevdan; Camas, Mustafa

    2016-08-01

    Effects of chronic exposure to alpha and gamma iron oxide nanoparticles (α-Fe2O3 and γ-Fe2O3 NPs) were investigated through exposure of tilapia (Oreochromis niloticus) to 0.1, 0.5 and 1.0mg/L (9.2×10(-4), 4.6×10(-3) and 9.2×10(-3)mM) aqueous suspensions for 60days. Fish were then transferred to NP-free freshwater and allowed to eliminate ingested NPs for 30days. The organs, including gills, liver, kidney, intestine, brain, spleen, and muscle tissue of the fish were analyzed to determine the accumulation, physiological distribution and elimination of the Fe2O3 NPs. Largest accumulation occurred in spleen followed by intestine, kidney, liver, gills, brain and muscle tissue. Fish exposed to γ-Fe2O3 NPs possessed significantly higher Fe in all organs. Accumulation in spleen was fast and independent of NP concentration reaching to maximum levels by the end of the first sampling period (30th day). Dissolved Fe levels in water were very negligible ranging at 4-6μg/L for α-Fe2O3 and 17-21μg/L for γ-Fe2O3 NPs (for 1mg/L suspensions). Despite that, Fe levels in gills and brain reflect more dissolved Fe accumulation from metastable γ-Fe2O3 polymorph. Ingested NPs cleared from the organs completely within 30-day elimination period, except the liver and spleen. Liver contained about 31% of α- and 46% of γ-Fe2O3, while spleen retained about 62% of α- and 35% of the γ-polymorph. No significant disturbances were observed in hematological parameters, including hemoglobin, hematocrit, red blood cell and white blood cell counts (p>0.05). Serum glucose (GLU) levels decreased in treatments exposed to 1.0mg/L of γ-Fe2O3 NPs at day 30 (p<0.05). In contrast, GLU levels increased during the elimination period for 1.0mg/L α-Fe2O3 NPs treatments (p<0.05). Transient increases occurred in glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), and lactate dehydrogenase (LDH). Serum Fe levels did not change during exposure (p>0.05), but increased

  14. Surgical smoke and ultrafine particles

    PubMed Central

    Brüske-Hohlfeld, Irene; Preissler, Gerhard; Jauch, Karl-Walter; Pitz, Mike; Nowak, Dennis; Peters, Annette; Wichmann, H-Erich

    2008-01-01

    Background Electrocautery, laser tissue ablation, and ultrasonic scalpel tissue dissection all generate a 'surgical smoke' containing ultrafine (<100 nm) and accumulation mode particles (< 1 μm). Epidemiological and toxicological studies have shown that exposure to particulate air pollution is associated with adverse cardiovascular and respiratory health effects. Methods To measure the amount of generated particulates in 'surgical smoke' during different surgical procedures and to quantify the particle number concentration for operation room personnel a condensation particle counter (CPC, model 3007, TSI Inc.) was applied. Results Electro-cauterization and argon plasma tissue coagulation induced the production of very high number concentration (> 100000 cm-3) of particles in the diameter range of 10 nm to 1 μm. The peak concentration was confined to the immediate local surrounding of the production side. In the presence of a very efficient air conditioning system the increment and decrement of ultrafine particle occurrence was a matter of seconds, with accumulation of lower particle number concentrations in the operation room for only a few minutes. Conclusion Our investigation showed a short term very high exposure to ultrafine particles for surgeons and close assisting operating personnel – alternating with longer periods of low exposure. PMID:19055750

  15. Scaling behavior of quantum nanosystems: Emergence of quasi-particles, collective modes, and mixed exchange symmetry states

    SciTech Connect

    Shreif, Zeina; Ortoleva, Peter

    2011-03-14

    Examples of quantum nanosystems are graphene nanoribbons, molecular wires, and superconducting nanoparticles. The objective of the multiscale theory presented here is to provide a new perspective on the coupling of processes across scales in space and time underlying the dynamics of these systems. The long range objective for this multiscale approach is to serve as an efficient computational algorithm. Long space-time dynamics is derived using a perturbation expansion in the ratio {epsilon} of the nearest-neighbor distance to a nanometer-scale characteristic length and a theorem on the equivalence of long time-averages and expectation values. This dynamics is shown to satisfy a coarse-grained wave equation (CGWE) which takes a Schroedinger-like form with modified masses and interactions. The scaling of space and time is determined by the orders of magnitude of various contributions to the N-body potential. If the spatial scale of the coarse-graining is too large, the CGWE would imply an unbounded growth of gradients; if it is too short, the system's size would display uncontrolled growth inappropriate for the bound states of interest, i.e., collective motion or migration within a stable nanoassembly. The balance of these two extremes removes arbitrariness in the choice of the scaling of space-time. Since the long-scale dynamics of each Fermion involves its interaction with many others, we hypothesize that the solutions of the CGWE have mean-field character to good approximation, i.e., can be factorized into single-particle functions. This leads to a coarse-grained mean-field approximation that is distinct in character from traditional Hartree-Fock theory. A variational principle is used to derive equations for the single-particle functions. This theme is developed and used to derive an equation for low-lying disturbances from the ground state corresponding to long wavelength density disturbances or long-scale migration. An algorithm for the efficient simulation of

  16. Scaling behavior of quantum nanosystems: emergence of quasi-particles, collective modes, and mixed exchange symmetry states.

    PubMed

    Shreif, Zeina; Ortoleva, Peter

    2011-03-14

    Examples of quantum nanosystems are graphene nanoribbons, molecular wires, and superconducting nanoparticles. The objective of the multiscale theory presented here is to provide a new perspective on the coupling of processes across scales in space and time underlying the dynamics of these systems. The long range objective for this multiscale approach is to serve as an efficient computational algorithm. Long space-time dynamics is derived using a perturbation expansion in the ratio ɛ of the nearest-neighbor distance to a nanometer-scale characteristic length and a theorem on the equivalence of long time-averages and expectation values. This dynamics is shown to satisfy a coarse-grained wave equation (CGWE) which takes a Schrödinger-like form with modified masses and interactions. The scaling of space and time is determined by the orders of magnitude of various contributions to the N-body potential. If the spatial scale of the coarse-graining is too large, the CGWE would imply an unbounded growth of gradients; if it is too short, the system's size would display uncontrolled growth inappropriate for the bound states of interest, i.e., collective motion or migration within a stable nanoassembly. The balance of these two extremes removes arbitrariness in the choice of the scaling of space-time. Since the long-scale dynamics of each Fermion involves its interaction with many others, we hypothesize that the solutions of the CGWE have mean-field character to good approximation, i.e., can be factorized into single-particle functions. This leads to a coarse-grained mean-field approximation that is distinct in character from traditional Hartree-Fock theory. A variational principle is used to derive equations for the single-particle functions. This theme is developed and used to derive an equation for low-lying disturbances from the ground state corresponding to long wavelength density disturbances or long-scale migration. An algorithm for the efficient simulation of

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

    PubMed

    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. PMID:26764837

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Characteristics of divertor heat and particle deposition with intrinsic and applied 3-D fields in NSTX H-mode plasmas

    SciTech Connect

    Ahn, J.W.; Canik, John; Maingi, Rajesh; Gray, Travis K; Lore, Jeremy D; McLean, Adam G; Park, J.-K.; Roquemore, A. L.; Soukhanovskii, V. A.

    2011-01-01

    Divertor heat and particle flux profiles are modified by externally imposed non-axisymmetric magnetic perturbations in the National Spherical Torus Experiment. The applied 3-D field causes strike point splitting that is represented as local peaks and valleys in the divertor profiles. The plasma response in an ideal perturbed equilibrium approach was included in the field line tracing by taking account of the B-field generated by the plasma current up to a certain fraction of normalized flux inside the separatrix and being superposed to the vacuum field. The inclusion of this type of plasma response does not significantly affect the location and spacing of the split strike points at the divertor surface. A modest level of divertor profile modification is found to occur even without the application of 3-D fields in certain high triangularity (delta = 0.65-0.8) discharges, with the location of local peaks and valleys same before and after the application. The intrinsic error field from the non-circularity of PF5 coil is known to have primarily n = 3 component in NSTX and was modeled to be included in the vacuum field line tracing. The produced puncture plot of the field line along with the connection length profile shows that the radial location of local peaks agrees well with the measurement, identifying intrinsic error field as a possible source of intrinsic strike point splitting. The radial location of local peaks in the profiles during the triggered ELM by the applied n = 3 field is the same before and after the 3-D field application. This shows that the heat flux from the triggered ELMs appears to follow the imposed n = 3 field structure.

  20. Characteristics of Fine Particles in an Urban Atmosphere-Relationships with Meteorological Parameters and Trace Gases.

    PubMed

    Zhang, Tianhao; Zhu, Zhongmin; Gong, Wei; Xiang, Hao; Fang, Ruimin

    2016-01-01

    Atmospheric fine particles (diameter < 1 μm) attract a growing global health concern and have increased in urban areas that have a strong link to nucleation, traffic emissions, and industrial emissions. To reveal the characteristics of fine particles in an industrial city of a developing country, two-year measurements of particle number size distribution (15.1 nm-661 nm), meteorological parameters, and trace gases were made in the city of Wuhan located in central China from June 2012 to May 2014. The annual average particle number concentrations in the nucleation mode (15.1 nm-30 nm), Aitken mode (30 nm-100 nm), and accumulation mode (100 nm-661 nm) reached 4923 cm(-3), 12193 cm(-3) and 4801 cm(-3), respectively. Based on Pearson coefficients between particle number concentrations and meteorological parameters, precipitation and temperature both had significantly negative relationships with particle number concentrations, whereas atmospheric pressure was positively correlated with the particle number concentrations. The diurnal variation of number concentration in nucleation mode particles correlated closely with photochemical processes in all four seasons. At the same time, distinct growth of particles from nucleation mode to Aitken mode was only found in spring, summer, and autumn. The two peaks of Aitken mode and accumulation mode particles in morning and evening corresponded obviously to traffic exhaust emissions peaks. A phenomenon of "repeated, short-lived" nucleation events have been created to explain the durability of high particle concentrations, which was instigated by exogenous pollutants, during winter in a case analysis of Wuhan. Measurements of hourly trace gases and segmental meteorological factors were applied as proxies for complex chemical reactions and dense industrial activities. The results of this study offer reasonable estimations of particle impacts and provide references for emissions control strategies in industrial cities of developing

  1. Characteristics of Fine Particles in an Urban Atmosphere—Relationships with Meteorological Parameters and Trace Gases

    PubMed Central

    Zhang, Tianhao; Zhu, Zhongmin; Gong, Wei; Xiang, Hao; Fang, Ruimin

    2016-01-01

    Atmospheric fine particles (diameter < 1 μm) attract a growing global health concern and have increased in urban areas that have a strong link to nucleation, traffic emissions, and industrial emissions. To reveal the characteristics of fine particles in an industrial city of a developing country, two-year measurements of particle number size distribution (15.1 nm–661 nm), meteorological parameters, and trace gases were made in the city of Wuhan located in central China from June 2012 to May 2014. The annual average particle number concentrations in the nucleation mode (15.1 nm–30 nm), Aitken mode (30 nm–100 nm), and accumulation mode (100 nm–661 nm) reached 4923 cm−3, 12193 cm−3 and 4801 cm−3, respectively. Based on Pearson coefficients between particle number concentrations and meteorological parameters, precipitation and temperature both had significantly negative relationships with particle number concentrations, whereas atmospheric pressure was positively correlated with the particle number concentrations. The diurnal variation of number concentration in nucleation mode particles correlated closely with photochemical processes in all four seasons. At the same time, distinct growth of particles from nucleation mode to Aitken mode was only found in spring, summer, and autumn. The two peaks of Aitken mode and accumulation mode particles in morning and evening corresponded obviously to traffic exhaust emissions peaks. A phenomenon of “repeated, short-lived” nucleation events have been created to explain the durability of high particle concentrations, which was instigated by exogenous pollutants, during winter in a case analysis of Wuhan. Measurements of hourly trace gases and segmental meteorological factors were applied as proxies for complex chemical reactions and dense industrial activities. The results of this study offer reasonable estimations of particle impacts and provide references for emissions control strategies in industrial cities of

  2. Variation of particle number concentration and size distributions at the urban environment in Vilnius (Lithuania)

    NASA Astrophysics Data System (ADS)

    Ulevicius, Vidmantas; Byčenkienë, Steigvilë; Plauškaitë, Kristina; Dudoitis, Vadimas

    2013-05-01

    This study presents results of research on urban aerosol particles with a focus on the particle size distribution and the aerosol particle number concentration (PNC). The real time measurements of the aerosol PNC in the size range of 9-840 nm were performed at the urban background site using a Condensed Particle Counter and Scanning Mobility Particle Sizer (SMPS). Strong diurnal patterns in aerosol PNC were evident as a direct effect of three sources of the aerosol particles (nucleation, traffic, and residential heating appliances). The traffic exhaust emissions were a major contributor of the pollution observed at the roadside site that was dominated by the nucleation mode particles, while particles formed due to the residential heating appliances and secondary formation processes contributed to the accumulation mode particles and could impact the variation of PNC and its size distribution during the same day.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Gyrokinetic particle simulation of beta-induced Alfven eigenmode

    SciTech Connect

    Zhang, H. S.; Lin, Z.; Holod, I.; Xiao, Y.; Wang, X.; Zhang, W. L.

    2010-11-15

    The beta-induced Alfven eigenmode (BAE) in toroidal plasmas is studied using global gyrokinetic particle simulations. The BAE real frequency and damping rate measured in the initial perturbation simulation and in the antenna excitation simulation agree well with each other. The real frequency is slightly higher than the ideal magnetohydrodynamic (MHD) accumulation point frequency due to the kinetic effects of thermal ions. Simulations with energetic particle density gradient show exponential growth of BAE with a growth rate sensitive to the energetic particle temperature and density. The nonperturbative contributions by energetic particles modify the mode structure and reduce the frequency relative to the MHD theory. The finite Larmor radius effects of energetic particles reduce the BAE growth rate. Benchmarks between gyrokinetic particle simulation and hybrid MHD-gyrokinetic simulation show good agreement in BAE real frequency and mode structure.

  6. Effect of wood combustion conditions on the morphology of freshly emitted fine particles

    NASA Astrophysics Data System (ADS)

    Torvela, T.; Tissari, J.; Sippula, O.; Kaivosoja, T.; Leskinen, J.; Virén, A.; Lähde, A.; Jokiniemi, J.

    2014-04-01

    The physical and chemical properties of biomass combustion-originated particles produced under controlled conditions (efficient, intermediate, and smouldering combustion) were studied. Transmission electron microscopy with energy dispersive X-ray spectroscopy was used to study the morphology and chemical composition of the size-classified samples collected from the flue gas. In addition, online-measured particle number size distributions, chemical analyses of the PM samples, and thermodynamic equilibrium calculations were used to interpret the results. The particles were composed of inorganic species and carbonaceous matter. Zinc oxide particles with an average diameter of <13 nm acted as seeds for the condensation of inorganic vapours and organic material, forming ash particles with a nested structure. The outer layer was composed mainly of alkali salts. Soot and gaseous hydrocarbons were formed in high concentrations during the impaired combustion conditions. Two modes of particle size distribution were observed, with each exhibiting distinctive features. The main particle type found in the ultrafine particle size mode (<100 nm) was ash. Impairing the combustion conditions increased the release of soot and condensable organics into the PM, found mainly in the accumulation particle size mode (>100 nm). TEM observations of the size-classified samples revealed that condensed organic matter influenced the ash particle size and appearance. The soot morphology was also found to change, even after short periods of time, due to the presence of OM; changes in the primary particle diameter and the appearance of the agglomerates were observed. As external mixtures, the soot and ash particles were separated into two particle size modes, but both could be found as internally mixed from the accumulation mode. This result extends the current knowledge of particle formation in wood combustion, showing that the particle formation processes of ash and soot particles are largely

  7. Consumption of low doses of fat prevents the postprandial rise in chylomicron particle concentration and remnant accumulation in healthy normolipidaemic males

    PubMed Central

    James, Anthony P.; Mamo, John C.

    2012-01-01

    Chylomicron particles are continually synthesised and secreted from the intestine even in the absence of ingested fat. It is possible that following consumption of low doses of fat the basal level of chylomicron secretion and subsequent metabolism are sufficient to metabolise this fat without an increase in postprandial chylomicron concentrations. To test this hypothesis, healthy male subjects were randomised to receive, on three separate occasions, meals containing a range of doses of fat (average 8·1–19 g) and effects on postprandial lipaemia and chylomicron concentration were determined. Furthermore, to delineate the effect on lipid-rich v. lipid-poor (remnant) forms lipid levels were also determined in a density <1·006 g/ml fraction. Following consumption of the very low dose of fat the postprandial concentration of chylomicrons was unaltered, whereas following the medium dose postprandial chylomicron concentrations were significantly increased. Interestingly, this increase was only detected in the lipid-rich chylomicron fraction, with postprandial levels of chylomicron remnants remaining unchanged. In conclusion, it appears that consumption of what would be considered low to medium doses of fat are not associated with transient postprandial increases in chylomicron remnants in healthy male subjects. PMID:25191552

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

    SciTech Connect

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

    2014-11-15

    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.

  9. Solids Accumulation Scouting Studies

    SciTech Connect

    Duignan, M. R.; Steeper, T. J.; Steimke, J. L.

    2012-09-26

    The objective of Solids Accumulation activities was to perform scaled testing to understand the behavior of remaining solids in a Double Shell Tank (DST), specifically AW-105, at Hanford during multiple fill, mix, and transfer operations. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles containing plutonium could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste staging tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids: Gibbsite, Zirconia, Sand, and Stainless Steel, with stainless steel particles representing the heavier particles, e.g., plutonium, and supernatant were charged to the test tank and rotating liquid jets were used to mix most of the solids while the simulant was pumped out. Subsequently, the volume and shape of the mounds of residual solids and the spatial concentration profiles for the surrogate for heavier particles were measured. Several techniques were developed and equipment designed to accomplish the measurements needed and they included: 1. Magnetic particle separator to remove simulant stainless steel solids. A device was designed and built to capture these solids, which represent the heavier solids during a waste transfer from a staging tank. 2. Photographic equipment to determine the volume of the solids mounds. The mounds were photographed as they were exposed at different tank waste levels to develop a composite of topographical areas. 3. Laser rangefinders to determine the volume of

  10. Particle preconcentrator

    DOEpatents

    Linker, K.L.; Conrad, F.J.; Custer, C.A.; Rhykerd, C.L. Jr.

    1998-12-29

    An apparatus and method are disclosed for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents. 3 figs.

  11. Particle preconcentrator

    SciTech Connect

    Linker, K.L.; Conrad, F.J.; Custer, C.A.; Rhykerd, C.L. Jr

    2000-07-11

    An apparatus and method are disclosed for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a previous screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  12. Particle preconcentrator

    SciTech Connect

    Linker, Kevin L.; Conrad, Frank J.; Custer, Chad A.; Rhykerd, Jr., Charles L.

    1998-01-01

    An apparatus and method for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  13. Particle preconcentrator

    SciTech Connect

    Linker, Kevin L.; Conrad, Frank J.; Custer, Chad A.; Rhykerd, Jr., Charles L.

    2005-09-20

    An apparatus and method for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  14. Particle preconcentrator

    SciTech Connect

    Linker, Kevin L.; Conrad, Frank J.; Custer, Chad A.; Rhykerd, Jr., Charles L.

    2000-01-01

    An apparatus and method for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  15. Source apportionment of ambient fine particle from combined size distribution and chemical composition data during summertime in Beijing

    NASA Astrophysics Data System (ADS)

    Liu, Z. R.; Wang, Y. S.; Liu, Q.; Hu, B.; Sun, Y.

    2013-01-01

    Continuous particle number concentration and chemical composition data were collected over one month during summertime in Beijing to investigate the source apportionment of ambient fine particles. Particle size distributions from 15 nm to 2.5 μm in diameter and composition data, such as organic matter, sulfate, nitrate, ammonium, chlorine, and gaseous pollutants, were analyzed using positive matrix factorisation (PMF) which indentified eight factors: cooking, solid mode exhaust, nucleation mode exhaust, accumulation mode, secondary nitrate, secondary sulfate, coal-fired power plant and road dust. Nearly two-thirds of particle number concentrations were attributed to cooking (22.8%) and motor vehicle (37.5%), whereas road dust, coal-fired power plant and regional sources contributed 69.0% to particle volume concentrations. Local and remote sources were distinguished using size distributions associated with each factor. Local sources were generally characterised by unimodal or bimodal number distributions, consisting mostly of particles less 0.1 μm in diameter, and regional sources were defined by mostly accumulation mode particles. Nearly one third of secondary nitrate and secondary sulfate was transported from the surrounding areas of Beijing during study period. Overall the introduction of combination of particle number concentration and chemical composition in PMF model is successful at separating the components and quantifying relative contributions to the particle number and volume population in a complex urban atmosphere.

  16. [Distribution of atmospheric ultrafine particles during haze weather in Hangzhou].

    PubMed

    Chen, Qiu-Fang; Sun, Zai; Xie, Xiao-Fang

    2014-08-01

    Atmospheric ultrafine particles (UFPs) were monitored with fast mobility particle sizer (FMPS) in continuous haze weather and the haze fading process during December 6 to 11, 2013 in Hangzhou. Particle concentration and size distribution were studied associated with meteorological factors. The results showed that number concentrations were the highest at night and began to reduce in the morning. There was a small peak at 8 o'clock in the morning and 18 o'clock in the afternoon. It showed an obvious peak traffic source, which indicated that traffic emissions played a great role in the atmospheric pollution. During haze weather, the highest number concentration of UFPs reached 8 x 10(4) cm(-3). Particle size spectrum distribution was bimodal, the peak particle sizes were 15 nm and 100 nm respectively. Majority of UFPs were Aitken mode and Accumulation mode and the size of most particles concentrated near 100 nm. Average CMD(count medium diameter) was 85.89 nm. During haze fading process, number concentration and particles with size around 100 nm began to reduce and peak size shifted to small size. Nuclear modal particles increased and were more than accumulation mode. Average CMD was 58.64 nm. Meteorological factors such as the visibility and wind were negatively correlated with the particle number concentration. Correlation coefficient R were -0.225 and - 0.229. The humidity was correlated with number concentration. Correlation coefficient R was 0.271. The atmosphere was stable in winter and the level temperature had small correlation with number concentration. Therefore, study on distribution of atmospheric ultrafine particles during haze weather had the significance on the formation mechanism and control of haze weather. PMID:25338351

  17. In situ studies on volatile jet exhaust particle emissions: Impact of fuel sulfur content and environmental conditions on nuclei mode aerosols

    NASA Astrophysics Data System (ADS)

    Schröder, F.; Brock, C. A.; Baumann, R.; Petzold, A.; Busen, R.; Schulte, P.; Fiebig, M.

    2000-08-01

    In situ measurements of ultrafine aerosol particle emissions were performed at cruise altitudes behind the Deutsches Zentrum für Luft-und Raumfahrt ATTAS research jet (Rolls-Royce/Snecma M45H M501 engines) and a B737-300 aircraft (CFM International 56-3B1 engines). Measurements were made 0.15-20 s after emission as the source aircraft burned fuel with sulfur contents (FSC) of 2.6, 56, or 118mg kg-1. Particle size distributions of from 3- to 60-nm diameter were determined by using condensationnuclei-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 60mg kg-1, reaching minimum values of about 2×1017kg-1 and 2×1016kg-1 for particles >3nm and >5nm, respectively. Volatile particle emissions did not change significantly as FSCs were further reduced below 60mg kg-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 (4×1014kg-1) than from the older RR M45H M501 engines (1.8×1015kg-1). Contrail processing has been identified as an efficient sink/quenching parameter for ultrafine particles and reduces the remaining interstitial aerosol by factors of 2-10 depending on particle size. These and previously published data are consistent with volatile particle emissions of 2.4×1017kg-1 independent of environmental conditions, engine type and FSCs ranging between 2.6 and 2700mg kg-1. There are clear experimental indications that

  18. Characterization of ultrafine particle number concentration and new particle formation in an urban environment of Taipei, Taiwan

    NASA Astrophysics Data System (ADS)

    Cheung, H. C.; Chou, C. C.-K.; Huang, W.-R.; Tsai, C.-Y.

    2013-09-01

    An intensive aerosol characterization experiment was performed at the Taipei Aerosol and Radiation Observatory (TARO, 25.02° N, 121.53° E) in the urban area of Taipei, Taiwan, during July 2012. Number concentration and size distribution of aerosol particles were measured continuously, which were accompanied by concurrent measurements of mass concentration of submicron particles, PM1 (d ≤ 1 μm), and photolysis rate of ozone, J(O1D). The averaged number concentrations of total (Ntotal), accumulation mode (Nacu), Aitken mode (NAitken), and nucleation mode (Nnuc) particles were 13.9 × 103 cm-3, 1.2 × 103 cm-3, 6.1 × 103 cm-3, and 6.6 × 103 cm-3, respectively. Accordingly, the ultrafine particles (UFPs, d ≤ 100 nm) accounted for 91% of the total number concentration of particles measured in this study (10 ≤ d ≤ 429 nm), indicating the importance of UFPs to the air quality and radiation budget in Taipei and its surrounding areas. An averaged Nnuc / NOx ratio of 192.4 cm-3 ppbv-1 was derived from nighttime measurements, which was suggested to be the characteristic of vehicle emissions that contributed to the "urban background" of nucleation mode particles throughout a day. On the contrary, it was found that the number concentration of nucleation mode particles was independent of NOx and could be elevated up to 10 times of the "urban background" levels during daytime, suggesting a substantial amount of nucleation mode particles produced from photochemical processes. Averages (± 1σ) of the diameter growth rate (GR) and formation rate of nucleation mode particles, J10, were 11.9 ± 10.6 nm h-1 and 6.9 ± 3.0 cm-3 s-1, respectively. Consistency in the time series of the nucleation mode particle concentration and the proxy of H2SO4 production, UVB · SO2/CS, for new particle formation (NPF) events suggested that photooxidation of SO2 was likely one of the major mechanisms for the formation of new particles in our study area. Moreover, it was revealed that the

  19. Short- and long-lived radionuclide particle size measurements in a uranium mine

    SciTech Connect

    Tu, Keng-Wu; Fisenne, I.M.; Hutter, A.R.

    1997-04-01

    The radon-222 progeny and long-lived radionuclide measurements were done in a wet underground uranium mine in Saskatchewan, Canada, on Nov. 8-12, 1995. Radon-222 in the mine varied from 2 kBq/m{sup 3} at 90 m below surface to 12 kBq/m{sup 3} in the mining areas, 240 m below surface. Radon-222 progeny activity and potential alpha energy concentration appear affected by the airborne particle number concentration and size distribution. Particle number was up to 200x10{sup 3}/cm{sup 3}. Only an accumulation mode (30-1000 nm) and some bimodal size distributions in this accumulation size range were significant. Diesel particles and combustion particles from burning propane caused a major modal diameter shift to a smaller size range (50-85 nm) compared with previous values (100-200 nm). The high particle number reduced the unattached progeny (0.5-2 nm) to >5%. The nuclei mode (2-30 nm) in this test was nonexistent, and the coarse mode (>1000 nm), except from the drilling areas and on the stopes, was mostly not measurable. Airborne particle total mass and long- lived radionuclide alpha activity concentrations were very low (80- 100 {mu}g/m{sup 3} and 4-5 mBq/m{sup 3}) owing to high ventilation rates. Mass-weighted size distributions were trimodal, with the major mode at the accumulation size region, which accounts for 45-50% of the mass. The coarse model contains the the least mass, about 20%. The size spectra from gross alpha activities were bimodal with major mode in the coarse region (>1000 nm) and a minor accumulation mode in the 50-900 nm size range. These size spectra were different from the {sup 222}Rn progeny that showed a single accumulation mode in the 50- 85 nm size region. The accumulation mode in the long-lived radionuclide size spectrum was not found in previous studies in other uranium mines.

  20. Manipulation of gold colloidal nanoparticles with atomic force microscopy in dynamic mode: influence of particle-substrate chemistry and morphology, and of operating conditions.

    PubMed

    Darwich, Samer; Mougin, Karine; Rao, Akshata; Gnecco, Enrico; Jayaraman, Shrisudersan; Haidara, Hamidou

    2011-01-01

    One key component in the assembly of nanoparticles is their precise positioning to enable the creation of new complex nano-objects. Controlling the nanoscale interactions is crucial for the prediction and understanding of the behaviour of nanoparticles (NPs) during their assembly. In the present work, we have manipulated bare and functionalized gold nanoparticles on flat and patterned silicon and silicon coated substrates with dynamic atomic force microscopy (AFM). Under ambient conditions, the particles adhere to silicon until a critical drive amplitude is reached by oscillations of the probing tip. Beyond that threshold, the particles start to follow different directions, depending on their geometry, size and adhesion to the substrate. Higher and respectively, lower mobility was observed when the gold particles were coated with methyl (-CH(3)) and hydroxyl (-OH) terminated thiol groups. This major result suggests that the adhesion of the particles to the substrate is strongly reduced by the presence of hydrophobic interfaces. The influence of critical parameters on the manipulation was investigated and discussed viz. the shape, size and grafting of the NPs, as well as the surface chemistry and the patterning of the substrate, and finally the operating conditions (temperature, humidity and scan velocity). Whereas the operating conditions and substrate structure are shown to have a strong effect on the mobility of the particles, we did not find any differences when manipulating ordered vs random distributed particles. PMID:21977418

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

    SciTech Connect

    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).

  2. Number size distributions and seasonality of submicron particles in Europe 2008-2009

    NASA Astrophysics Data System (ADS)

    Asmi, A.; Wiedensohler, A.; Laj, P.; Fjaeraa, A.-M.; Sellegri, K.; Birmili, W.; Weingartner, E.; Baltensperger, U.; Zdimal, V.; Zikova, N.; Putaud, J.-P.; Marinoni, A.; Tunved, P.; Hansson, H.-C.; Fiebig, M.; Kivekäs, N.; Lihavainen, H.; Asmi, E.; Ulevicius, V.; Aalto, P. P.; Swietlicki, E.; Kristensson, A.; Mihalopoulos, N.; Kalivitis, N.; Kalapov, I.; Kiss, G.; de Leeuw, G.; Henzing, B.; Harrison, R. M.; Beddows, D.; O'Dowd, C.; Jennings, S. G.; Flentje, H.; Weinhold, K.; Meinhardt, F.; Ries, L.; Kulmala, M.

    2011-03-01

    Two years of harmonized aerosol number size distribution data from 24 European field monitoring sites have been analysed. The results give a comprehensive overview of the European near surface aerosol particle number concentrations and number size distributions between 30 and 500 nm of dry particle diameter. Spatial and temporal distribution of aerosols in the particle sizes most important for climate applications are presented. We also analyse the annual, weekly and diurnal cycles of the aerosol number concentrations, provide log-normal fitting parameters for median number size distributions, and give guidance notes for data users. Emphasis is placed on the usability of results within the aerosol modelling community. We also show that the aerosol number concentrations of Aitken and accumulation mode particles (with 100 nm dry diameter as a cut-off between modes) are related, although there is significant variation in the ratios of the modal number concentrations. Different aerosol and station types are distinguished from this data and this methodology has potential for further categorization of stations aerosol number size distribution types. The European submicron aerosol was divided into characteristic types: Central European aerosol, characterized by single mode median size distributions, unimodal number concentration histograms and low variability in CCN-sized aerosol number concentrations; Nordic aerosol with low number concentrations, although showing pronounced seasonal variation of especially Aitken mode particles; Mountain sites (altitude over 1000 m a.s.l.) with a strong seasonal cycle in aerosol number concentrations, high variability, and very low median number concentrations. Southern and Western European regions had fewer stations, which decreases the regional representativeness of these results. Aerosol number concentrations over the Britain and Ireland had very high variance and there are indications of mixed air masses from several source regions

  3. Number size distributions and seasonality of submicron particles in Europe 2008-2009

    NASA Astrophysics Data System (ADS)

    Asmi, A.; Wiedensohler, A.; Laj, P.; Fjaeraa, A.-M.; Sellegri, K.; Birmili, W.; Weingartner, E.; Baltensperger, U.; Zdimal, V.; Zikova, N.; Putaud, J.-P.; Marinoni, A.; Tunved, P.; Hansson, H.-C.; Fiebig, M.; Kivekäs, N.; Lihavainen, H.; Asmi, E.; Ulevicius, V.; Aalto, P. P.; Swietlicki, E.; Kristensson, A.; Mihalopoulos, N.; Kalivitis, N.; Kalapov, I.; Kiss, G.; de Leeuw, G.; Henzing, B.; Harrison, R. M.; Beddows, D.; O'Dowd, C.; Jennings, S. G.; Flentje, H.; Weinhold, K.; Meinhardt, F.; Ries, L.; Kulmala, M.

    2011-06-01

    Two years of harmonized aerosol number size distribution data from 24 European field monitoring sites have been analysed. The results give a comprehensive overview of the European near surface aerosol particle number concentrations and number size distributions between 30 and 500 nm of dry particle diameter. Spatial and temporal distribution of aerosols in the particle sizes most important for climate applications are presented. We also analyse the annual, weekly and diurnal cycles of the aerosol number concentrations, provide log-normal fitting parameters for median number size distributions, and give guidance notes for data users. Emphasis is placed on the usability of results within the aerosol modelling community. We also show that the aerosol number concentrations of Aitken and accumulation mode particles (with 100 nm dry diameter as a cut-off between modes) are related, although there is significant variation in the ratios of the modal number concentrations. Different aerosol and station types are distinguished from this data and this methodology has potential for further categorization of stations aerosol number size distribution types. The European submicron aerosol was divided into characteristic types: Central European aerosol, characterized by single mode median size distributions, unimodal number concentration histograms and low variability in CCN-sized aerosol number concentrations; Nordic aerosol with low number concentrations, although showing pronounced seasonal variation of especially Aitken mode particles; Mountain sites (altitude over 1000 m a.s.l.) with a strong seasonal cycle in aerosol number concentrations, high variability, and very low median number concentrations. Southern and Western European regions had fewer stations, which decreases the regional coverage of these results. Aerosol number concentrations over the Britain and Ireland had very high variance and there are indications of mixed air masses from several source regions; the

  4. The effects of an open and closed divertor on particle exhaust during edge-localized mode suppression by resonant magnetic perturbations in DIII-D

    SciTech Connect

    Unterberg, E. A.; Schmitz, O.; Evans, T.E.; Maingi, Rajesh; Brooks, N. H.; Fenstermacher, M. E.; Mordijck, S.; Moyer, R.A.; Orlov, D. M.

    2010-01-01

    This paper compares the effects of divertor geometry on particle exhaust characteristics during the suppression of ELM using resonant magnetic perturbations (RMPs) on DIII-D. The subject is timely, particularly for ITER, because the combination of techniques to control or mitigate ELMs and control particle exhaust can provide confidence in the ability of an external pumping system to fully remove the particle exhaust. The differences between an open and closed divertor magnetic topology show a strong coupling of the perturbed strikepoint to the pumping manifold in closed divertor configurations, which can increase the particle exhaust by a factor of four. There is also an observed dependence on q(95) in this configuration, which is a common feature of RMP ELM suppression. Neutral density in both the active and non-active divertors is seen to increase during the RMP in the ISS configuration, and edge plasma conditions (i.e. n(e,sep) and midplane profile of D(alpha)) are seen to increase in the closed divertor configuration. Finally, the pumping exhaust is also shown to have a strong dependence on local measurements of the recycling flux. These observations, when taken as a whole, point to a substantial change in the plasma edge conditions, i.e. near the LCFS, throughout the poloidal cross-section of the vacuum vessel. This is coincident with the application of the RMP affecting the pumping capability of the system.

  5. Excursions through KK modes

    NASA Astrophysics Data System (ADS)

    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.

  6. Accumulation of calcium and loss of potassium in the hippocampus following transient cerebral ischemia: a proton microprobe study

    SciTech Connect

    Martins, E.; Inamura, K.; Themner, K.; Malmqvist, K.G.; Siesjoe, B.K.

    1988-08-01

    This study explored (a) whether postischemic accumulation of calcium in hippocampal neurons precedes or occurs pari passu with light microscopical signs of delayed neuronal necrosis, and (b) whether calcium initially accumulates in dendritic domains, presumed to have a high density of agonist-operated calcium channels. Transient ischemia of 10-min duration was induced in rats, and the animals were studied after 1, 2, 3, and 4 days of recovery. We measured total calcium and potassium contents in the stratum oriens, pyramidale, radiatum, and moleculare of the CA1 and CA3 sectors, using particle induced x-ray emission (PIXE) in the proton microprobe mode. The results showed significant accumulation of calcium and loss of potassium after 3 and 4 days of recovery in the CA1 sector, which developed neuronal necrosis, but not in the CA3 sector, which showed only occasional damage. In a few animals, calcium accumulation (and loss of potassium) was observed with no or only mild visible damage, but in the majority of animals the accumulation of calcium correlated to signs of neuronal necrosis. Since calcium accumulation was similar in all strata examined, the results failed to reveal preferential accumulation in dendritic or somal regions. Based on our results and those of Dux et al., we emphasize the possibility that delayed neuronal death is, at least in part, caused by increased calcium cycling of plasma membranes and gradual calcium overload of mitochondria.

  7. Impact of the Pedestal on Global Performance and Confinement Scalings in I-mode

    NASA Astrophysics Data System (ADS)

    Walk, John; Hughes, Jerry; Hubbard, Amanda; Whyte, Dennis; White, Anne; Alcator C-Mod Team

    2015-11-01

    The I-mode is a novel high-confinement regime pioneered on Alcator C-Mod, notable for its strong temperature pedestal without the accompanying density pedestal found in conventional H-modes. This separation in transport channels gives the desired improved energy confinement while maintaining low particle confinement, avoiding excessive impurity accumulation. Moreover, I-mode operation is naturally free of deleterious Edge-Localized Modes (ELMs). Recent experiments on Alcator C-Mod have characterized the pedestal structure in I-mode. The impact of the pedestal response (particularly to fueling and heating power) and core profile stiffness on global performance and confinement have demonstrated confinement metrics competitive with H-mode operation on Alcator C-Mod, and consistent with concepts for I-mode access & operation on ITER. Following the practice of the ITER89 and ITER98 scaling laws for L- and H-mode energy confinement, an initial, illustrative attempt at an I-mode confinement scaling has also been developed. The initial characterization from C-Mod data is consistent with the observed pedestal properties in I-mode, particularly the weak degradation of energy confinement with heating power, and comparatively strong positive response to fueling and increased magnetic field. Supported by U.S. Department of Energy award DE-FC02-99ER54512, using Alcator C-Mod, a DOE Office of Science User Facility.

  8. Electrostatic particle collection in vacuum

    NASA Astrophysics Data System (ADS)

    Afshar-Mohajer, Nima; Damit, Brian; Wu, Chang-Yu; Sorloaica-Hickman, Nicoleta

    2011-09-01

    Lunar grains accumulate charges due to solar-based ionizing radiations, and the repelling action of like-charged particles causes the levitation of lunar dust. The lunar dust deposit on sensitive and costly surfaces of investigative equipment is a serious concern in lunar explorations. Inspired by electrostatic precipitators (ESPs), the Electrostatic Lunar Dust Collector (ELDC) was proposed for collecting already charged lunar dust particles to prevent the lunar dust threat. As the conditions for terrestrial counterparts are not valid in the lunar environment, equations developed for terrestrial devices yield incorrect predictions in lunar application. Hence, a mathematical model was developed for the ELDC operating in vacuum to determine its collection efficiency. The ratios of electrical energy over potential energy, kinetic energy over potential energy and the ratio of ELDC dimensions were identified to be the key dimensionless parameters. Sensitivity analyses of the relevant parameters showed that depending on ELDC orientation, smaller particles would be collected more easily at vertical orientation, whereas larger particles were easier to collect in a horizontal ELDC configuration. In the worst case scenario, the electrostatic field needed to be 10 times stronger in the vertical mode in order to adequately collect larger particles. The collection efficiency was very sensitive to surface potential of lunar dust and it reached the maximum when surface potential was between 30 and 120 V. Except for regions of the lunar day side with surface potential close to zero, providing 1 kV ( E = 20 kV m -1) with the ELDC was more than enough for collecting all the particles in the most critical orientation. The needed field strength was about 4000 times less than that for repelling 1-μm size particles already settled on the surfaces. The analysis shows that the ELDC offers a viable solution for lunar dust control due to its effectiveness, ease of cleaning and low voltage

  9. Fast carry accumulator design

    NASA Technical Reports Server (NTRS)

    Mastin, W. C.

    1971-01-01

    Simple iterative accumulator combined with gated-carry, carry-completion detection, and skip-carry circuits produces three accumulators with decreased carry propagation times. Devices are used in machine control, measurement equipment, and computer applications to increase speed of binary addition. NAND gates are used in combining network.

  10. Characterization of ultrafine particle number concentration and new particle formation in urban environment of Taipei, Taiwan

    NASA Astrophysics Data System (ADS)

    Cheung, H. C.; Chou, C. C.-K.; Huang, W.-R.; Tsai, C.-Y.

    2013-04-01

    An intensive aerosol characterization experiment was performed at the Taipei Aerosol and Radiation Observatory (TARO, 25.02° N, 121.53° E) in the urban area of Taipei, Taiwan during July 2012. Number concentration and size distribution of aerosol particles were measured continuously, which were accompanied by concurrent measurements of mass concentration of submicron particles, PM (d ≤ 1 μm), and photolysis rate of ozone, J(O1D). The averaged number concentrations of total (Ntotal), accumulation mode (Nacu), Aitken mode (Ntotal), and nucleation mode (Nnuc) particles were 7.6 × 103 cm-3, 1.2 × 103 cm-3, 4.4 × 103 cm-3, and 1.9 × 103 cm-3, respectively. Accordingly, the ultrafine particles (UFPs, d ≤ 100 nm) accounted for 83% of the total number concentration of particles measured in this study (10 ≤ d ≤ 429 nm), indicating the importance of UFPs to the air quality and radiation budget in Taipei and its surrounding areas. An averaged Nnuc/NOx ratio of ~60 cm-3 ppbv-1 was derived from nighttime measurements, which was suggested to be the characteristic of vehicle emissions that contributed to the "urban background" of nucleation mode particles throughout a day. On the contrary, it was found that the number concentration of nucleation mode particles was independent of NOx and could be elevated up to 10 times the "urban background" levels during daytime, suggesting a substantial amount of nucleation mode particles produced from photochemical processes. Consistency in the time series of the nucleation mode particle concentration and the proxy of H2SO4 production, UVB·SO2, for new particle formation (NPF) events showed that photo-oxidation of SO2 was responsible for the formation of new particles in our study area. Moreover, analysis upon the diameter growth rate, GR, and formation rate of nucleation mode particles, J10-25, found that the values of GR (8.5 ± 6.8 nm h-1) in Taipei were comparable to other urban areas, whereas the values of J10-25 (2.2 ± 1

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

    NASA Astrophysics Data System (ADS)

    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. Influence of breathing mode and activity level on the regional deposition of inhaled particles and implications for regulatory standards (March 1986)

    SciTech Connect

    Miller, F.J.; Martonen, T.B.; Menache, M.G.; Graham, R.C.; Spektor, D.M.

    1986-03-01

    Particulate-size-selective sampling is an important consideration in determining ambient air-quality standards and threshold limit values for workplace exposures. Hazard evaluations, as well as risk analyses, can benefit from an improved understanding of factors affecting regional respiratory tract deposition of particles in man. Here, thoracic deposition and its component parts are examined, as a function of particulate size, for ventilation rates ranging from normal respiration to heavy exercise in individuals who are habitual mouth breathers and in those who normally employ oronasal breathing when minute ventilations exceed approximately 35 Lmin-1. Nonlinear regression techniques were used to fit logistic models of the form Y = (1+e alpha+beta log X)-1 to data from tests measuring extrathoracic (ET) and tracheobronchial (TB) deposition.

  13. Aerosol number size distributions over a coastal semi urban location: Seasonal changes and ultrafine particle bursts.

    PubMed

    Babu, S Suresh; Kompalli, Sobhan Kumar; Moorthy, K Krishna

    2016-09-01

    Number-size distribution is one of the important microphysical properties of atmospheric aerosols that influence aerosol life cycle, aerosol-radiation interaction as well as aerosol-cloud interactions. Making use of one-yearlong measurements of aerosol particle number-size distributions (PNSD) over a broad size spectrum (~15-15,000nm) from a tropical coastal semi-urban location-Trivandrum (Thiruvananthapuram), the size characteristics, their seasonality and response to mesoscale and synoptic scale meteorology are examined. While the accumulation mode contributed mostly to the annual mean concentration, ultrafine particles (having diameter <100nm) contributed as much as 45% to the total concentration, and thus constitute a strong reservoir, that would add to the larger particles through size transformation. The size distributions were, in general, bimodal with well-defined modes in the accumulation and coarse regimes, with mode diameters lying in the range 141 to 167nm and 1150 to 1760nm respectively, in different seasons. Despite the contribution of the coarse sized particles to the total number concentration being meager, they contributed significantly to the surface area and volume, especially during transport of marine air mass highlighting the role of synoptic air mass changes. Significant diurnal variation occurred in the number concentrations, geometric mean diameters, which is mostly attributed to the dynamics of the local coastal atmospheric boundary layer and the effect of mesoscale land/sea breeze circulation. Bursts of ultrafine particles (UFP) occurred quite frequently, apparently during periods of land-sea breeze transitions, caused by the strong mixing of precursor-rich urban air mass with the cleaner marine air mass; the resulting turbulence along with boundary layer dynamics aiding the nucleation. These ex-situ particles were observed at the surface due to the transport associated with boundary layer dynamics. The particle growth rates from

  14. In-vehicle particle air pollution and its mitigation

    NASA Astrophysics Data System (ADS)

    Tartakovsky, L.; Baibikov, V.; Czerwinski, J.; Gutman, M.; Kasper, M.; Popescu, D.; Veinblat, M.; Zvirin, Y.

    2013-01-01

    This work presents results of particle mass, number and size measurements inside passenger cars (PCs), vans and urban buses. Effects of the in-cabin air purifier on particle concentrations and average size inside a vehicle are studied. Use of the air purifier leads to a dramatic reduction, by 95-99%, in the measured ultrafine particles number concentration inside a vehicle compared with outside readings. Extremely low particle concentrations may be reached without a danger of vehicle occupants' exposure to elevated CO2 levels. The lowest values of particle concentrations inside a PC without air purifier are registered under the recirculation ventilation mode, but the issue of CO2 accumulation limits the use of this mode to very short driving events. Lower PM concentrations are found inside newer cars, if this ventilation mode is used. Great differences by a factor of 2.5-3 in PM10 concentrations are found between the PCs and the buses. Smoking inside a car leads to a dramatic increase, by approximately 90 times, in PM2.5 concentrations.

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

    PubMed

    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. PMID:26667647

  16. Modeled deposition of fine particles in human airway in Beijing, China

    NASA Astrophysics Data System (ADS)

    Li, Xiaoying; Yan, Caiqing; Patterson, Regan F.; Zhu, Yujiao; Yao, Xiaohong; Zhu, Yifang; Ma, Shexia; Qiu, Xinghua; Zhu, Tong; Zheng, Mei

    2016-01-01

    This study aims to simulate depositions of size-segregated particles in human airway in Beijing, China during seasons when fine particulate matter concentrations are high (December 2011 and April 2012). Particle size distributions (5.6-560 nm, electrical mobility diameter) near a major road in Beijing were measured by the TSI Fast Mobility Particle Sizer (FMPS). The information of size distributions provided by FMPS was applied in the Multiple-Path Particle Dosimetry model (MPPD) to quantify number and mass depositions of particles in human airway including extrathoracic (ET), tracheobronchial (TB), and pulmonary (PUL) regions of exposed Chinese in Beijing. Our results show that under ambient conditions, particle number concentration (NC) deposition in PUL is the highest in the three major regions of human airway. The total particle NC deposition in human airway in winter is higher than that in spring, especially for ultrafine particles (1.8 times higher) while particle mass concentration (MC) deposition is higher in spring. Although particle MC in clean days are much lower than that in heavily polluted days, total particle NC deposition in human airway in clean days is comparable to that in heavily polluted days. NC deposition for nucleation mode particles (10-20 nm, aerodynamic diameter) in clean days is higher than that in heavily polluted days. MC deposition for accumulation mode particles (100-641 nm, aerodynamic diameter) in heavily polluted days is much higher than that in clean days, while that of nucleation mode is negligible. The temporal variation shows that the arithmetic mean and the median values of particle NC and MC depositions in the evening are both the highest, followed by morning and noon, and it is most likely due to increased contribution from traffic emissions.

  17. Chemical characteristics and source of size-fractionated atmospheric particle in haze episode in Beijing

    NASA Astrophysics Data System (ADS)

    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 (< 1 μm, Ge, Se, Ag, Sn, Sb, Cs, Hg, Ti, and Pb); (II) those mass (K, Cr, Mn, Cu, Zn, As, Mo, and Cd) was resided mainly within the accumulation mode, ranged from 1 to 2 μm; (III) Na, V, Co, Ni, and Ga were distributed among fine, intermediate, and coarse modes; and (IV) those which were mainly found within particles larger than 2.7 μm (Al, Mg, Si, Ca, Sc, Tl, Fe, Sr, Zr, and Ba). [H+]cor showed an accumulation mode at 600-700 nm and the role of Ca2 + should be fully considered in the estimation of acidity. The acidity in accumulation mode particles suggested that generally gaseous NH3 was not enough to neutralize sulfate completely. PMF method was applied for source apportionment of elements combined with 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

  18. Formation and Growth of New Organic Aerosol Particles over the Deepwater Horizon Oil Spill

    NASA Astrophysics Data System (ADS)

    Brock, C. A.; Murphy, D. M.; Bahreini, R.; Middlebrook, A. M.; De Gouw, J. A.

    2011-12-01

    Aerosol size distributions were measured in June 2010 downwind of the surface oil slick produced by the Deepwater Horizon oil spill in the Gulf of Mexico. Rapid condensation of partially oxidized hydrocarbons was responsible for formation of a plume of secondary organic aerosol downwind of the spill region. New particles were nucleated upwind of the freshest surface oil but downwind of oil that surfaced less than 100 hours previously. These new particles grew by condensation at rates of ~20 nm hr-1; preexisting accumulation mode particles grew by ~10 nm hr-1. The gas-phase concentration of a condensing species necessary to support the observed growth rate assuming irreversible adsorption with unit accommodation coefficient is estimated to be ~0.04-0.09 μg m-3 (~3-8 pptv). The ratio of growth rates for newly formed particles to accumulation mode particles was consistent within error limits with irreversible condensation. Because new particle formation did not occur in areas away from the <100 hr-old oil slick, these results indicate that the oxidation products of VOC species, probably C14-C16 compounds, were directly involved in the growth of the new particles. While a unique and extreme environment, the oil spill plume provides insight into similar processes that may occur in urban and industrial areas where petrochemical products are produced and consumed.

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

    PubMed

    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. PMID:25766014

  20. Contribution of nitrated polycyclic aromatic hydrocarbons to the mutagenicity of ultrafine particles in the roadside atmosphere

    NASA Astrophysics Data System (ADS)

    Kawanaka, Youhei; Matsumoto, Emiko; Wang, Ning; Yun, Sun-Ja; Sakamoto, Kazuhiko

    This is the first report of the quantification of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) in ultrafine particles in the roadside atmosphere and their contribution to the direct-acting mutagenicity of ultrafine particles. The detailed size distributions of six nitro-PAHs (2-nitrofluoranthene, 1-nitropyrene, 6-nitrobenzo[a]pyrene, 1,3-dinitropyrene, 1,6-dinitropyrene, and 1,8-dinitropyrene) were measured by highly sensitive gas chromatography-negative ion chemical ionization tandem mass spectrometry. Direct-acting mutagenicity of size-fractionated particulate matter (PM) was determined by the Ames test using Salmonella typhimurium strains TA98 and YG1024. The amounts of nitro-PAHs per unit mass of ultrafine particles (<0.12 μm) were significantly higher than those of accumulation mode particles (0.12-2.1 μm) and of coarse particles (>2.1 μm). Therefore, more than 20% of each nitro-PAH, with the exception of 2-nitrofluoranthene, was observed in the ultrafine particle fraction, although the contribution of ultrafine particles to the total PM mass in the roadside atmosphere was only 2.3%. Also, in both tester strains TA98 and YG1024, the mutagenicity per unit mass of ultrafine particles was significantly higher than those of accumulation mode particles or coarse particles. The contributions of 2-nitrofluoranthene, 1-nitropyrene, 1,3-dinitropyrene, 1,6-dinitropyrene, and 1,8-dinitropyrene to the direct-acting mutagenicity of ultrafine particles were 0.56, 1.5, 0.57, 2.2, and 9.2%, respectively, in the TA98 strain, and 0.54, 1.1, 0.71, 5.0, and 17%, respectively, in the YG1024 strain, while the contribution of 6-nitrobenzo[a]pyrene was less than 0.01% in both strains. 1,8-Dinitropyrene was the largest contributor to the mutagenicity not only of ultrafine particles but also of accumulation mode particles in both strains. Only five nitro-PAHs accounted for as much as 14 and 24% of the direct-acting mutagenicity of ultrafine particles in the roadside

  1. Hygroscopic properties of ultrafine particles at an urban site in northern Japan during the summer of 2011

    NASA Astrophysics Data System (ADS)

    Jung, Jinsang; Kawamura, Kimitaka

    2013-04-01

    To investigate the hygroscopic property of ultrafine particles, hygroscopic growth factors [g(RH)] of size-segregated atmospheric particles were measured at an urban site in Sapporo, northern Japan, during the summer of 2011. Hygroscopic growth factors at 85% RH [g(85%)] of freshly formed nucleation mode particles ranged from 1.11 to 1.28 with an average of 1.16 ± 0.06. These values are similar to those of secondary organic aerosols, suggesting that low volatile organic vapors are important to the growth of nucleated clusters into quasi-stable aerosol particles larger than 3 nm. Higher g(85%) values (range: 1.21-1.31, AVG: 1.27 ± 0.04) were obtained for grown Aitken mode nucleated particles. This result may indicate that the growth of freshly formed nucleation mode particles to the Aitken mode particles at the urban site can be attributed to condensation not only of low volatility organic vapors but also of highly water-soluble inorganic compounds like sulfuric acid. Diel variations in the number concentrations of less-hygroscopic particles [g(85%) <1.05] were similar to those in NO concentrations, suggesting that less-hygroscopic particles are mainly produced by local anthropogenic emissions such as traffic. Higher g(85%) values (1.27 ± 0.05) were obtained at a dry particle diameter of 120 nm when the air masses originated from downwind areas of the Asian continent, whereas lower g(85%) values (1.19 ± 0.06) were obtained when clean marine air masses arrived in the urban site. These results indicate that the hygroscopic property of large Aitken and small accumulation mode particles (80-165 nm) are highly influenced by the long-range transport of atmospheric particles.

  2. The sign of the radiative forcing from marine cloud brightening depends on both particle size and injection amount

    NASA Astrophysics Data System (ADS)

    AlterskjæR, K.; KristjáNsson, J. E.

    2013-01-01

    Marine cloud brightening (MCB) is a proposed technique to limit global warming through injections of sea spray into the marine boundary layer. Using the Norwegian Earth System Model, the sensitivity of MCB to sea salt amount and particle size was studied by running a set of simulations in which Aitken (re = 0.04 µm), accumulation (re = 0.22 µm), or coarse (re = 2.46 µm) mode sea salt emissions were increased uniformly by 10-11 to 10-8 kg m-2 s-1. As desired, accumulation mode particles had a negative radiative effect of down to -3.3 W m-2. Conversely, for Aitken mode particles, injections of 10-10 kg m-2 s-1 or greater led to a positive forcing of up to 8.4 W m-2, caused by a strong competition effect combined with the high critical supersaturation of Aitken mode sea salt. The coarse mode particles gave a positive forcing of up to 1.2 W m-2 because of a decrease in activation of background aerosols. Sensitivity experiments show that the competition effect dominated our results. MCB may have a cooling effect, but if the wrong size or injection amount is used, our simulations show a warming effect on the climate system.

  3. Hygroscopicity of aerosol particles and CCN activity of nearly hydrophobic particles in the urban atmosphere over Japan during summer

    NASA Astrophysics Data System (ADS)

    Ogawa, Shuhei; Setoguchi, Yoshitaka; Kawana, Kaori; Nakayama, Tomoki; Ikeda, Yuka; Sawada, Yuuki; Matsumi, Yutaka; Mochida, Michihiro

    2016-06-01

    We investigated the hygroscopicity of 150 nm particles and the number-size distributions and the cloud condensation nuclei (CCN) activity of nearly hydrophobic particles in aerosols over Nagoya, Japan, during summer. We analyzed the correlations between the number concentrations of particles in specific hygroscopic growth factor (g) ranges and the mass concentrations of chemical components. This analysis suggests the association of nearly hydrophobic particles with hydrocarbon-like organic aerosol, elemental carbon and semivolatile oxygenated organic aerosol (SV-OOA), that of less hygroscopic particles with SV-OOA and nitrate and that of more hygroscopic particles with low-volatile oxygenated organic aerosol (LV-OOA) and sulfate. The hygroscopicity parameter (κ) of organics was derived based on the g distributions and chemical composition of 150 nm particles. The κ of the organics correlated positively with the fraction of the total organic mass spectral signal at m/z 44 and the volume fraction of the LV-OOA to the organics, indicating that organics with highly oxygenated structures including carboxylic acid groups contribute to the water uptake. The number-size distributions of the nearly hydrophobic particles with g around 1.0 and 1.1 correlated with the mass concentrations of chemical components. The results show that the chemical composition of the particles with g around 1.0 was different between the Aitken mode and the accumulation mode size ranges. An analysis for a parameter Fmax of the curves fitted to the CCN efficiency spectra of the particles with g around 1.0 suggests that the coating by organics associated with SV-OOA elevated the CCN activity of these particles.

  4. Neurodegeneration with Brain Iron Accumulation

    MedlinePlus

    ... Diversity Find People About NINDS NINDS Neurodegeneration with Brain Iron Accumulation Information Page Synonym(s): Hallervorden-Spatz Disease, ... done? Clinical Trials Organizations What is Neurodegeneration with Brain Iron Accumulation? Neurodegeneration with brain iron accumulation (NBIA) ...

  5. Constraining primordial vector mode from B-mode polarization

    SciTech Connect

    Saga, Shohei; Ichiki, Kiyotomo; Shiraishi, Maresuke E-mail: maresuke.shiraishi@pd.infn.it

    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.

  6. Plastids and Carotenoid Accumulation.

    PubMed

    Li, Li; Yuan, Hui; Zeng, Yunliu; Xu, Qiang

    2016-01-01

    Plastids are ubiquitously present in plants and are the organelles for carotenoid biosynthesis and storage. Based on their morphology and function, plastids are classified into various types, i.e. proplastids, etioplasts, chloroplasts, amyloplasts, and chromoplasts. All plastids, except proplastids, can synthesize carotenoids. However, plastid types have a profound effect on carotenoid accumulation and stability. In this chapter, we discuss carotenoid biosynthesis and regulation in various plastids with a focus on carotenoids in chromoplasts. Plastid transition related to carotenoid biosynthesis and the different capacity of various plastids to sequester carotenoids and the associated effect on carotenoid stability are described in light of carotenoid accumulation in plants. PMID:27485226

  7. Variations of fine particle physiochemical properties during a heavy haze episode in the winter of Beijing.

    PubMed

    Niu, Hongya; Hu, Wei; Zhang, Daizhou; Wu, Zhijun; Guo, Song; Pian, Wei; Cheng, Wenjing; Hu, Min

    2016-11-15

    Chemical composition, morphology, size and mixture of fine particles were measured in a heavy haze and the post-haze air in Beijing in January 2012. With the occurrence of haze, the concentrations of gaseous and particulate pollutants including organics, sulfate, nitrate, and ammonium grew gradually. The hourly averaged PM2.5 concentration increased from 118μgm(-3) to 402μgm(-3) within 12h. In contrast, it was less than 10μgm(-3) in the post-haze air. Occupying approximately 46% in mass, organics were the major component of PM1 in both the haze and post-haze air. Analysis of individual particles in the size range of 0.2-1.1μm revealed that secondary-like particles and soot particles were always the majority, and most soot particles had a core-shell structure. The number ratio of secondary-like particles to soot particles in accumulation mode in the haze air was about 2:1, and that in the post-haze air was 8:1. These results indicate both secondary particle formation and primary emission contributed substantially to the haze. The mode size of the haze particles was about 0.7μm, and the mode size of the post-haze particles was 0.4μm, indicating the remarkable growth of particles in haze. However, the ratios of the core size to shell size of core-shell structure soot particles in the haze were similar to those in the post-haze air, suggesting a quick aging of soot particles in either the haze air or the post-haze air. PMID:27470669

  8. Chimpanzee accumulative stone throwing.

    PubMed

    Kühl, Hjalmar S; Kalan, Ammie K; Arandjelovic, Mimi; Aubert, Floris; D'Auvergne, Lucy; Goedmakers, Annemarie; Jones, Sorrel; Kehoe, Laura; Regnaut, Sebastien; Tickle, Alexander; Ton, Els; van Schijndel, Joost; Abwe, Ekwoge E; Angedakin, Samuel; Agbor, Anthony; Ayimisin, Emmanuel Ayuk; Bailey, Emma; Bessone, Mattia; Bonnet, Matthieu; Brazolla, Gregory; Buh, Valentine Ebua; Chancellor, Rebecca; Cipoletta, Chloe; Cohen, Heather; Corogenes, Katherine; Coupland, Charlotte; Curran, Bryan; Deschner, Tobias; Dierks, Karsten; Dieguez, Paula; Dilambaka, Emmanuel; Diotoh, Orume; Dowd, Dervla; Dunn, Andrew; Eshuis, Henk; Fernandez, Rumen; Ginath, Yisa; Hart, John; Hedwig, Daniela; Ter Heegde, Martijn; Hicks, Thurston Cleveland; Imong, Inaoyom; Jeffery, Kathryn J; Junker, Jessica; Kadam, Parag; Kambi, Mohamed; Kienast, Ivonne; Kujirakwinja, Deo; Langergraber, Kevin; Lapeyre, Vincent; Lapuente, Juan; Lee, Kevin; Leinert, Vera; Meier, Amelia; Maretti, Giovanna; Marrocoli, Sergio; Mbi, Tanyi Julius; Mihindou, Vianet; Moebius, Yasmin; Morgan, David; Morgan, Bethan; Mulindahabi, Felix; Murai, Mizuki; Niyigabae, Protais; Normand, Emma; Ntare, Nicolas; Ormsby, Lucy Jayne; Piel, Alex; Pruetz, Jill; Rundus, Aaron; Sanz, Crickette; Sommer, Volker; Stewart, Fiona; Tagg, Nikki; Vanleeuwe, Hilde; Vergnes, Virginie; Willie, Jacob; Wittig, Roman M; Zuberbuehler, Klaus; Boesch, Christophe

    2016-01-01

    The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites. PMID:26923684

  9. Chimpanzee accumulative stone throwing

    PubMed Central

    Kühl, Hjalmar S.; Kalan, Ammie K.; Arandjelovic, Mimi; Aubert, Floris; D’Auvergne, Lucy; Goedmakers, Annemarie; Jones, Sorrel; Kehoe, Laura; Regnaut, Sebastien; Tickle, Alexander; Ton, Els; van Schijndel, Joost; Abwe, Ekwoge E.; Angedakin, Samuel; Agbor, Anthony; Ayimisin, Emmanuel Ayuk; Bailey, Emma; Bessone, Mattia; Bonnet, Matthieu; Brazolla, Gregory; Buh, Valentine Ebua; Chancellor, Rebecca; Cipoletta, Chloe; Cohen, Heather; Corogenes, Katherine; Coupland, Charlotte; Curran, Bryan; Deschner, Tobias; Dierks, Karsten; Dieguez, Paula; Dilambaka, Emmanuel; Diotoh, Orume; Dowd, Dervla; Dunn, Andrew; Eshuis, Henk; Fernandez, Rumen; Ginath, Yisa; Hart, John; Hedwig, Daniela; Ter Heegde, Martijn; Hicks, Thurston Cleveland; Imong, Inaoyom; Jeffery, Kathryn J.; Junker, Jessica; Kadam, Parag; Kambi, Mohamed; Kienast, Ivonne; Kujirakwinja, Deo; Langergraber, Kevin; Lapeyre, Vincent; Lapuente, Juan; Lee, Kevin; Leinert, Vera; Meier, Amelia; Maretti, Giovanna; Marrocoli, Sergio; Mbi, Tanyi Julius; Mihindou, Vianet; Moebius, Yasmin; Morgan, David; Morgan, Bethan; Mulindahabi, Felix; Murai, Mizuki; Niyigabae, Protais; Normand, Emma; Ntare, Nicolas; Ormsby, Lucy Jayne; Piel, Alex; Pruetz, Jill; Rundus, Aaron; Sanz, Crickette; Sommer, Volker; Stewart, Fiona; Tagg, Nikki; Vanleeuwe, Hilde; Vergnes, Virginie; Willie, Jacob; Wittig, Roman M.; Zuberbuehler, Klaus; Boesch, Christophe

    2016-01-01

    The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites. PMID:26923684

  10. Accumulation of the planets

    NASA Technical Reports Server (NTRS)

    Wetherill, G. W.

    1987-01-01

    In modeling the accumulation of planetesimals into planets, it is appropriate to distinguish between two stages: an early stage, during which approximately 10 km diameter planetesimals accumulate locally to form bodies approximate 10 to the 25th g in mass; and a later stage in which the approximately 10 to the 25th g planetesimals accumulate into the final planets. In the terrestrial planet region, an initial planetesimal swarm corresponding to the critical mass of dust layer gravitational instabilities is considered. In order to better understand the accumulation history of Mercury-sized bodies, 19 Monte-Carlo simulations of terrestrial planet growth were calculated. A Monte Carlo technique was used to investigate the orbital evolution of asteroidal collision debris produced interior to 2.6 AU. It was found that there are two regions primarily responsible for production of Earth-crossing meteoritic material and Apollo objects. The same techniques were extended to include the origin of Earth-approaching asteroidal bodies. It is found that these same two resonant mechanisms predict a steady-state number of Apollo-Amor about 1/2 that estimated based on astronomical observations.

  11. Particle number size distribution in the eastern Mediterranean: Formation and growth rates of ultrafine airborne atmospheric particles

    NASA Astrophysics Data System (ADS)

    Kopanakis, I.; Chatoutsidou, S. E.; Torseth, K.; Glytsos, T.; Lazaridis, M.

    2013-10-01

    Particle number concentration was measured between June 2009 and June 2010 at Akrotiri research station in a rural/suburban region of western Crete (Greece). Overall, the available data covered 157 days during the aforementioned period of measurements. The objectives were to study the number size distribution characteristics of ambient aerosols and furthermore to identify new particle formation events and to evaluate particle formation rates and growth rates of the newborn particles. Aerosol particles with mobility diameters between 10 and 1100 nm were measured using a Scanning Mobility Particle Sizer (SMPS) system. Measurements were performed at ambient relative humidities. The median total particle number concentration was 525 #/cm3 whereas the number concentration ranged between 130 #/cm3 and 9597 #/cm3. The average percentage of particles with diameters between 10 nm and 100 nm (N10-100) to total particles was 53% during summer and spring, but reached 80% during winter. Maximum average contribution of nano-particles (10 nm < Dp < 50 nm) to total particles was recorded also in winter and was attributed partly to the effect of local heating. Furthermore, back trajectories (HYSPLIT model) showed that different air mass origins are linked to different levels of particle number concentrations, with higher values associated with air masses passing from polluted areas before reaching the Akrotiri station. Modal analysis of the measured size distribution data revealed a strong nucleation mode during winter (15-25 nm), which can be correlated with emissions from local sources (domestic heating). The nucleation mode was observed also during the spring campaigns and was partly linked to new particle formation events. On the contrary, an accumulation mode (80-120 nm) prevailed in the measurements during summer campaigns, when the station area was influenced by polluted air masses arriving mainly from Eastern Europe. In total, 13 new particle formation events were recorded

  12. Particle deposition to forests: An alternative to K-theory

    NASA Astrophysics Data System (ADS)

    Huang, Cheng-Wei; Launiainen, Samuli; Grönholm, Tiia; Katul, Gabriel G.

    2014-09-01

    It has been known for some time that flux-gradient closure schemes (or K-theory), widely used to model the aerosol sized particle turbulent diffusivity, are problematic within canopies. Reported momentum transport in a zero- or counter-mean velocity gradient flow within open trunk spaces of forests is prototypical of the failure of K-theory. To circumvent this problem, a multi-layered and size-resolved second-order closure model is developed using the mean particle turbulent flux budget as a primary closure for the particle turbulent flux instead of K-theory. The proposed model is evaluated against the multi-level size-resolved particle fluxes and particle concentration measurements conducted within and above a tall Scots pine forest situated in Hyytiälä, Southern Finland. Conditions promoting the failure of K-theory for different particle sizes and canopy layers and the characteristics of the particle transport processes within the canopy sub-layer (CSL) are discussed. Using the model, it is shown that K-theory may still be plausible for modeling the particle deposition velocity when the particle size range is smaller than 1 μm provided the local particle turbulent diffusivity is estimated from the characteristic turbulent relaxation time scale and the vertical velocity variance. Model calculations suggest that the partitioning of particle deposition onto foliage and forest floor appears insensitive to the friction velocity for particles smaller than 100 nm (ultrafine), but decreases with increasing friction velocity for particles larger than 100 nm (accumulation and coarse modes).

  13. Dynamics of ultrafine particles inside a roadway tunnel.

    PubMed

    Mishra, V K; Aggarwal, M L; Berghmans, P; Frijns, E; Int Panis, L; Chacko, K M

    2015-12-01

    Size-segregated ultrafine particles from motor vehicles were investigated in the Craeybeckx tunnel (E19 motorway, Antwerp, Belgium) at two measurement sites, at 100 and 300 m inside the tunnel, respectively, during March 2008. It was observed that out of the three size modes, nucleation, Aitken, and accumulation, Aitken mode was the most dominant size fraction inside the tunnel. The diurnal variation in ultrafine particle (UFP) levels closely follows the vehicular traffic inside the tunnel, which was maximum during office rush hours, both in the morning and evening and minimum during night-time around 3 am. The tunnel data showed very high growth rates in comparison with free atmosphere. The average condensation sink during the growth period was 14.1-17.3 × 10(-2) s(-1). The average growth rate (GR) of geometric mean diameter was found to be 18.6 ± 2.45 nm h(-1). It was observed that increase in Aitken mode was related to the numbers of heavy-duty vehicles (HDV), as they emit mainly in the Aitken mode. The higher Aitken mode during traffic jams correlated well with HDV numbers. At the end of the tunnel, sudden dilution leading to fast coagulation was responsible for the sudden drop in the UFP number concentration. PMID:26577216

  14. Optical scattering patterns from single urban aerosol particles at Adelphi, Maryland, USA: A classification relating to particle morphologies

    NASA Astrophysics Data System (ADS)

    Aptowicz, K. B.; Pinnick, R. G.; Hill, S. C.; Pan, Y. L.; Chang, R. K.

    2006-06-01

    Angularly resolved elastic light scattering patterns from individual atmospheric aerosol particles (diameter 0.5-12 micrometers) sampled during fall (October 2004) at an urban site in the Baltimore-Washington metroplex are reported. These two-dimensional angular optical scattering (TAOS) patterns were collected for polar scattering angles θ varying from approximately 75° to 135° and azimuthal angles ϕ varying from 0° to 360°. Approximately 6000 scattering patterns were sampled over a span of 18 hours from an inlet located above our laboratory roof at Adelphi, Maryland. Our instrument recorded light scattering patterns of higher resolution and accuracy than have previously been achievable. The patterns suggest that background aerosol particles have diverse morphologies ranging from single spheres to complex structures. The frequency of occurrence of particle morphologies inferred from the TAOS patterns is strongly dependent on size. For nominally 1-μm particles, 65% appear spherical (or perturbed sphere) and only about 9% have complex structure (as suggested by their complex scattering features); whereas for nominally 5-μm particles, only 5% appear spherical (or perturbed sphere) and 71% appear to have complex structure. The patterns are quantitatively characterized using a degree of symmetry (Dsym) factor, calculated by examining both mirror and rotational symmetries in each pattern. In our measurements, atmospheric particles have two distinct populations: mostly micron-sized particles with Dsym values close to that of spheres and a population of mostly supermicron particles having a low but broad range of Dsym values. These observations are consistent with the commonly accepted notion that most micron-sized particles (in the accumulation mode) appear to be nearly spherical and are probably formed in the atmosphere through gas-particle reactions; whereas most supermicron particles appear to be nonspherical and are likely directly injected into the

  15. Landscape Evolution and Carbon Accumulation: Uniformitarianism Revisited

    NASA Astrophysics Data System (ADS)

    Rosenbloom, N. A.; Harden, J. W.; Neff, J. C.; Schimel, D. S.

    2003-12-01

    What is the role of hillslope transport in long-term carbon accumulation in soils? How do parent material, climate, and landform interact to produce the landscapes we observe today and to what extent can we use present day conditions to infer the dominant processes of the past? We use the CREEP [Rosenbloom, N.A. et al., 2001] process-response model to ask these questions, exploring the time-evolution of landscape form, soil distribution, and carbon accumulation in an undisturbed prairie site in western Iowa [Harden, J.W. et al., 2002]. The CREEP model simulates differential transport of soil particles, blanket deposition of atmospheric 10Be with eolian dust, and passive advection of soil carbon and 10Be, enabling the preferential enrichment and burial of rapidly moving soil constituents. By comparing landscape-wide average accumulations of 10Be to borehole observations at three hillslope positions, we conclude that the distribution of clay-adsorbed 10Be cannot be explained by co-transport with clay particles alone. Rather, 10Be appears to behave as a more complex tracer than originally assumed, requiring an explicit, independent parameterization of wet deposition and transport. By comparison, model carbon accumulation strongly reflects patterns of clay redistribution indicating that in situ carbon turnover is faster than redistribution. Observed vertical distributions of soil properties, including 10Be, could only be explained by assuming variations in deposition and erosion rates, specifically periods of accumulation, followed by periods of transport. This effect might not be apparent if only landform shape, geometry, and soil depth were considered and vertical distributions of soil properties were not explicitly simulated. The current landscape reflects a history of strong shifts in erosion and accumulation rates that cannot be simulated using a uniform parameterization of long-term landscape-evolution processes.

  16. Particle fluxes and condensational uptake over sea ice during COBRA

    NASA Astrophysics Data System (ADS)

    Whitehead, J. D.; Dorsey, J. R.; Gallagher, M. W.; Flynn, M. J.; McFiggans, G.; Carpenter, L. J.

    2012-08-01

    Particle fluxes were measured over sea ice at Hudson Bay, Canada, during the COBRA experiment in February and March, 2008. Eddy covariance particle fluxes were measured using a condensation particle counter and an ultrasonic anemometer on a 2.5 m mast on the sea ice. After applying appropriate corrections and filtering, the mean net deposition velocity was 0.12 ± 0.11 mm s-1 for particles measured with a CPC 3776 (lower size threshold, Dp50 = 2.5 nm) and was at the detection limit of the measurement system. No evidence of nucleation events was seen. Two optical particle counters (at heights 0.2 and 1.35 m on the mast) allowed size segregated fluxes of particles in the accumulation and coarse mode diameter range 0.3-20 μm to be derived using the aerodynamic flux gradient method. Strong net emission fluxes were observed around midday, 3rd March, when winds increased to around 10 m s-1, suggesting ice particle resuspension. The fluxes during this period had a significant influence on the derived condensational loss rate to the available particle surfaces, kt. Number fluxes were greatest in the smallest size channels, while the largest sizes dominated the mass flux. Number fluxes also increased with wind speed, and this relationship was strongest for the smaller sizes. Particle mass size distributions showed an enhanced mode around 400 nm (dry size). Values of kt were well approximated by the molecular regime and were found to be much smaller and less variable than values derived for marine air.

  17. Multiple mode model of tokamak transport

    SciTech Connect

    Singer, C.E.; Ghanem, E.S.; Bateman, G.; Stotler, D.P.

    1989-07-01

    Theoretical models for radical transport of energy and particles in tokamaks due to drift waves, rippling modes, and resistive ballooning modes have been combined in a predictive transport code. The resulting unified model has been used to simulate low confinement mode (L-mode) energy confinement scalings. Dependence of global energy confinement on electron density for the resulting model is also described. 26 refs., 1 fig., 2 tabs.

  18. Chemical composition, microstructure, and hygroscopic properties of aerosol particles at the Zotino Tall Tower Observatory (ZOTTO), Siberia, during a summer campaign

    NASA Astrophysics Data System (ADS)

    Mikhailov, E. F.; Mironov, G. N.; Pöhlker, C.; Chi, X.; Krüger, M. L.; Shiraiwa, M.; Förster, J.-D.; Pöschl, U.; Vlasenko, S. S.; Ryshkevich, T. I.; Weigand, M.; Kilcoyne, A. L. D.; Andreae, M. O.

    2015-08-01

    In this study we describe the hygroscopic properties of accumulation- and coarse-mode aerosol particles sampled at the Zotino Tall Tower Observatory (ZOTTO) in central Siberia (61° N, 89° E) from 16 to 21 June 2013. The hygroscopic growth measurements were supplemented with chemical analyses of the samples, including inorganic ions and organic/elemental carbon. In addition, the microstructure and chemical compositions of aerosol particles were analyzed by x-ray micro-spectroscopy (STXM-NEXAFS) and transmission electron microscopy (TEM). A mass closure analysis indicates that organic carbon accounted for 61 and 38 % of particulate matter (PM) in the accumulation mode and coarse mode, respectively. The water-soluble fraction of organic matter was estimated to be 52 and 8 % of PM in these modes. Sulfate, predominantly in the form of ammoniated sulfate, was the dominant inorganic component in both size modes: ~ 34 % in the accumulation mode vs. ~ 47 % in the coarse mode. The hygroscopic growth measurements were conducted with a filter-based differential hygroscopicity analyzer (FDHA) over the range of 5-99.4 % RH in the hydration and dehydration operation modes. The FDHA study indicates that both accumulation and coarse modes exhibit pronounced water uptake approximately at the same relative humidity (RH), starting at ~ 70 %, while efflorescence occurred at different humidities, i.e., at ~ 35 % RH for submicron particles vs. ~ 50 % RH for supermicron particles. This ~ 15 % RH difference was attributed to higher content of organic material in the submicron particles, which suppresses water release in the dehydration experiments. The kappa mass interaction model (KIM) was applied to characterize and parameterize non-ideal solution behavior and concentration-dependent water uptake by atmospheric aerosol samples in the 5-99.4 % RH range. Based on KIM, the volume-based hygroscopicity parameter, κv, was calculated. The κv,ws value related to the water-soluble (ws

  19. Evaluation of the particle measurement programme (PMP) protocol to remove the vehicles' exhaust aerosol volatile phase.

    PubMed

    Giechaskiel, B; Chirico, R; Decarlo, P F; Clairotte, M; Adam, T; Martini, G; Heringa, M F; Richter, R; Prevot, A S H; Baltensperger, U; Astorga, C

    2010-10-01

    European regulation for Euro 5/6 light duty emissions introduced the measurement of non-volatile particles with diameter >23 nm. The volatile phase is removed by using a heated dilution stage (150 degrees C) and a heated tube (at 300-400 degrees C). We investigated experimentally the removal efficiency for volatile species of the specific protocol by conducting measurements with two Euro 3 diesel light duty vehicles, a Euro 2 moped, and a Euro III heavy duty vehicle with the system's heaters on and off. The particle number distributions were measured with a Scanning Mobility Particle Sizer (SMPS) and a Fast Mobility Particle Sizer (FMPS). An Aerosol Mass Spectrometer (AMS) was used to identify the non-refractory chemical composition of the particles. A Multi-Angle Absorption Photometer (MAAP) was used to measure the black carbon concentration. The results showed that the condensed material in the accumulation mode (defined here as particles in the diameter range of approximately 50-500 nm) was removed with an efficiency of 50-90%. The (volatile) nucleation mode was also completely evaporated or was decreased to sizes <23 nm; thus these particles wouldn't be counted from the particle counter, indicating the robustness of the protocol. PMID:20692024

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Accumulation of radionuclides by plants as a monitor system.

    PubMed Central

    Koranda, J J; Robison, W L

    1978-01-01

    The accumulation of radionuclides by plants acting as a monitoring system in the environment may occur by two modes; foliar absorption by the leaves and shoot of the plant, or by root uptake from the soil. Data on plant accumulation of radionuclides may be obtained from studies of fission product radionuclides deposited as worldwide fallout, and from tracer studies of plant physiology. The epidermal features of plant foliage may exert an effect upon particle retention by leaves, and subsequent uptake of radionuclides from the surface. The transport of radionuclides across the cuticle and epidermis of plant leaves is determined in part by the anatomy of the leaf, and by physiological factors. The foliar uptake of fallout radionuclides, 99Sr, 131I, and 137Cs, is described with examples from the scientific literature. The environmental half-life of 131I, for example, is considerably shorter than its physical half-life because of physical and biological factors which may produce a half-life as short as 0.23/day. 99Sr and 137Cs are readily taken up by the leaf, but 137Cs undergoes more translocation into fruit and seeds than 99Sr which tends to remain in the plant part in which it was initially absorbed. Soil-root uptake is conditioned primarily by soil chemical and physical factors which may selectively retain a radionuclide, such as 137Cs. The presence of organic matter, inorganic colloids (clay), and competing elements will strongly affect the uptake of 99Sr and 137Cs by plants from the soil. The role of plants as monitors of radionuclides is twofold: as monitors of recent atmospheric releases of radionuclides; and as indicators of the long-term behavior of aged deposits of radionuclides in the soil. PMID:367767

  2. Heat exchanger-accumulator

    DOEpatents

    Ecker, Amir L.

    1980-01-01

    What is disclosed is a heat exchanger-accumulator for vaporizing a refrigerant or the like, characterized by an upright pressure vessel having a top, bottom and side walls; an inlet conduit eccentrically and sealingly penetrating through the top; a tubular overflow chamber disposed within the vessel and sealingly connected with the bottom so as to define an annular outer volumetric chamber for receiving refrigerant; a heat transfer coil disposed in the outer volumetric chamber for vaporizing the liquid refrigerant that accumulates there; the heat transfer coil defining a passageway for circulating an externally supplied heat exchange fluid; transferring heat efficiently from the fluid; and freely allowing vaporized refrigerant to escape upwardly from the liquid refrigerant; and a refrigerant discharge conduit penetrating sealingly through the top and traversing substantially the length of the pressurized vessel downwardly and upwardly such that its inlet is near the top of the pressurized vessel so as to provide a means for transporting refrigerant vapor from the vessel. The refrigerant discharge conduit has metering orifices, or passageways, penetrating laterally through its walls near the bottom, communicating respectively interiorly and exteriorly of the overflow chamber for controllably carrying small amounts of liquid refrigerant and oil to the effluent stream of refrigerant gas.

  3. [Research on NEDC ultrafine particle emission characters of a port fuel injection gasoline car].

    PubMed

    Hu, Zhi-Yuan; Li, Jin; Tan, Pi-Qiang; Lou, Di-Ming

    2012-12-01

    A Santana gasoline car with multi-port fuel injection (PFI) system was used as the research prototype and an engine exhaust particle sizer (EEPS) was employed to investigate the exhaust ultrafine particle number and size distribution characters of the tested vehicle in new European driving cycle (NEDC). The tested results showed that the vehicle's nuclear particle number, accumulation particle number, as well as the total particle number emission increased when the car drove in accelerated passage, and the vehicle's particle number emission was high during the first 40 seconds after test started and when the speed was over 90 km x h(-1) in extra urban driving cycle (EUDC) in NEDC. The ultrafine particle distribution of the whole NEDC showed a single peak logarithmic distribution, with diameters of the peak particle number emission ranging from 10 nm to 30 nm, and the geometric mean diameter was 24 nm. The ultrafine particle distribution of the urban driving cycle named by the economic commission for Europe (ECE) e. g. ECE I, ECE II - IV, the extra urban driving cycle e. g. EUDC, and the idling, constant speed, acceleration, deceleration operation conditions of NEDC all showed a single peak logarithmic distribution, also with particle diameters of the peak particle number emission ranging from 10 nm to 30 nm, and the geometric mean diameters of different driving cycle and different driving mode were from 14 nm to 42 nm. Therefore, the ultrafine particle emissions of the tested PFI gasoline car were mainly consisted of nuclear mode particles with a diameter of less than 50 nm. PMID:23379140

  4. Dual-cavity mode converter for a fundamental mode output in an over-moded relativistic backward-wave oscillator

    SciTech Connect

    Li, Jiawei; Huang, Wenhua; Xiao, Renzhen; Bai, Xianchen; Zhang, Yuchuan; Zhang, Xiaowei; Shao, Hao; Chen, Changhua; Zhu, Qi

    2015-03-16

    A dual-cavity TM{sub 02}–TM{sub 01} mode converter is designed for a dual-mode operation over-moded relativistic backward-wave oscillator. With the converter, the fundamental mode output is achieved. Particle-in-cell simulation shows that the efficiency of beam-wave conversion was over 46% and a pureTM{sub 01} mode output was obtained. Effects of end reflection provided by the mode converter were studied. Adequate TM{sub 01} mode feedback provided by the converter enhances conversion efficiency. The distance between the mode converter and extraction cavity critically affect the generation of microwaves depending on the reflection phase of TM{sub 01} mode feedback.

  5. Chemical composition, microstructure, and hygroscopic properties of aerosol particles at the Zotino Tall Tower Observatory (ZOTTO), Siberia, during a summer campaign

    DOE PAGESBeta

    Mikhailov, E. F.; Mironov, G. N.; Pöhlker, C.; Chi, X.; Krüger, M. L.; Shiraiwa, M.; Förster, J. -D.; Pöschl, U.; Vlasenko, S. S.; Ryshkevich, T. I.; et al

    2015-03-16

    In this study we describe the hygroscopic properties of accumulation- and coarse-mode aerosol particles sampled at the Zotino Tall Tower Observatory (ZOTTO) in Central Siberia (61° N; 89° E) from 16 to 21 June 2013. The hygroscopic growth measurements were supplemented with chemical analyses of the samples, including inorganic ions and organic/elemental carbon. In addition, the microstructure and chemical composition of aerosol particles were analyzed by X-ray micro-spectroscopy (STXM-NEXAFS) and transmission electron microscopy (TEM). A mass closure analysis indicates that organic carbon accounted for 61 and 38% of PM in the accumulation mode and coarse mode, respectively. The water solublemore » fraction of organic matter was estimated to be 52 and 8% of PM in these modes. Sulfate, predominantly in the form of ammoniated sulfate, was the dominant inorganic component in both size modes: ~ 34% in the accumulation vs. ~ 47% in the coarse mode. The hygroscopic growth measurements were conducted with a filter-based differential hygroscopicity analyzer (FDHA) over the range of 5–99.4% RH in the hydration and dehydration operation modes. The FDHA study indicates that both accumulation and coarse modes exhibit pronounced water uptake approximately at the same RH, starting at ~ 70%, while efflorescence occurred at different humidities, i.e., at ~ 35% RH for submicron particles vs. ~ 50% RH for supermicron particles. This ~ 15% RH difference was attributed to higher content of organic material in the submicron particles, which suppresses water release in the dehydration experiments. The kappa mass interaction model (KIM) was applied to characterize and parameterize non-ideal solution behavior and concentration-dependent water uptake by atmospheric aerosol samples in the 5–99.4% RH range. Based on KIM, the volume-based hygroscopicity parameter, κv, was calculated. The κv, ws value related to the water soluble (ws) fraction was estimated to be ~ 0.15 for the

  6. Chemical composition, microstructure, and hygroscopic properties of aerosol particles at the Zotino Tall Tower Observatory (ZOTTO), Siberia, during a summer campaign

    NASA Astrophysics Data System (ADS)

    Mikhailov, E. F.; Mironov, G. N.; Pöhlker, C.; Chi, X.; Krüger, M. L.; Shiraiwa, M.; Förster, J.-D.; Pöschl, U.; Vlasenko, S. S.; Ryshkevich, T. I.; Weigand, M.; Kilcoyne, A. L. D.; Andreae, M. O.

    2015-03-01

    In this study we describe the hygroscopic properties of accumulation- and coarse-mode aerosol particles sampled at the Zotino Tall Tower Observatory (ZOTTO) in Central Siberia (61° N; 89° E) from 16 to 21 June 2013. The hygroscopic growth measurements were supplemented with chemical analyses of the samples, including inorganic ions and organic/elemental carbon. In addition, the microstructure and chemical composition of aerosol particles were analyzed by X-ray micro-spectroscopy (STXM-NEXAFS) and transmission electron microscopy (TEM). A mass closure analysis indicates that organic carbon accounted for 61 and 38% of PM in the accumulation mode and coarse mode, respectively. The water soluble fraction of organic matter was estimated to be 52 and 8% of PM in these modes. Sulfate, predominantly in the form of ammoniated sulfate, was the dominant inorganic component in both size modes: ∼34% in the accumulation vs. ∼47% in the coarse mode. The hygroscopic growth measurements were conducted with a filter-based differential hygroscopicity analyzer (FDHA) over the range of 5-99.4% RH in the hydration and dehydration operation modes. The FDHA study indicates that both accumulation and coarse modes exhibit pronounced water uptake approximately at the same RH, starting at ∼70%, while efflorescence occurred at different humidities, i.e., at ∼35% RH for submicron particles vs. ∼50% RH for supermicron particles. This ∼15% RH difference was attributed to higher content of organic material in the submicron particles, which suppresses water release in the dehydration experiments. The kappa mass interaction model (KIM) was applied to characterize and parameterize non-ideal solution behavior and concentration-dependent water uptake by atmospheric aerosol samples in the 5-99.4% RH range. Based on KIM, the volume-based hygroscopicity parameter, κv, was calculated. The κv, ws value related to the water soluble (ws) fraction was estimated to be ∼0.15 for

  7. Volume accumulator design analysis computer codes

    NASA Technical Reports Server (NTRS)

    Whitaker, W. D.; Shimazaki, T. T.

    1973-01-01

    The computer codes, VANEP and VANES, were written and used to aid in the design and performance calculation of the volume accumulator units (VAU) for the 5-kwe reactor thermoelectric system. VANEP computes the VAU design which meets the primary coolant loop VAU volume and pressure performance requirements. VANES computes the performance of the VAU design, determined from the VANEP code, at the conditions of the secondary coolant loop. The codes can also compute the performance characteristics of the VAU's under conditions of possible modes of failure which still permit continued system operation.

  8. Nonmodal instability of a stratified plane-channel suspension flow with fine particles.

    PubMed

    Boronin, Sergei A; Osiptsov, Alexander N

    2016-03-01

    We consider the nonmodal instability and transient growth of small disturbances in a plane-channel suspension flow with a nonuniform concentration profile of fine noncolloidal particles accumulated in two localized layers, symmetric about the channel axis. A single-velocity model of an effective Newtonian fluid with a finite particle volume fraction is employed. It is established that fine particles distributed nonuniformly in the main flow significantly modify the growth rate of the first mode in a wide range of governing parameters. The most pronounced destabilizing effect is produced by the particles localized in the vicinity of the walls. A parametric study of the so-called optimal disturbances showed that they are streaks elongated in the flow direction, similar to the optimal disturbances in the flow devoid of particles. The transverse wave number of the optimal disturbances depends strongly on the location of the particle layers. Even when the particle mass concentration (averaged over the channel cross section) is small (of the order of a percent) and the particles are localized in the middle between the walls and the channel axis, the energy of the optimal disturbances is by several orders of magnitude larger than in dusty-gas and pure-fluid flows. When the particle layers are located in the vicinity of the walls or the channel axis, the nonmodal instability mechanism is less pronounced, as compared to the flow devoid of particles. PMID:27078447

  9. Relating the hygroscopic properties of submicron aerosol to both gas- and particle-phase chemical composition in a boreal forest environment

    NASA Astrophysics Data System (ADS)

    Hong, J.; Kim, J.; Nieminen, T.; Duplissy, J.; Ehn, M.; Äijälä, M.; Hao, L.; Nie, W.; Sarnela, N.; Prisle, N. L.; Kulmala, M.; Virtanen, A.; Petäjä, T.; Kerminen, V.-M.

    2015-06-01

    Measurements of the hygroscopicity of 15-145 nm particles in a boreal forest environment were conducted using two Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA) systems during the Pan-European Gas-AeroSOIs-climate interaction Study (PEGASOS) campaign in spring 2013. Measurements of the chemical composition of non-size segregated particles were also performed using a High-Resolution Aerosol Mass Spectrometer (HR-AMS) in parallel with hygroscopicity measurements. On average, the hygroscopic growth factor (HGF) of particles was observed to increase from the morning until afternoon. In case of accumulation mode particles, the main reasons for this behavior were increases in the ratio of sulfate to organic matter and oxidation level (O : C ratio) of the organic matter in the particle phase. Using an O : C dependent hygroscopic growth factor of organic matter (HGForg), fitted using the inverse Zdanovskii-Stokes-Robinson (ZSR) mixing rule, clearly improved the agreement between measured HGF and that predicted based on HR-AMS composition data. Besides organic oxidation level, the influence of inorganic species was tested when using the ZSR mixing rule to estimate the hygroscopic growth factor of organics in the aerosols. While accumulation and Aitken mode particles were predicted fairly well by the bulk aerosol composition data, the hygroscopicity of nucleation mode particles showed little correlation. However, we observed them to be more sensitive to the gas phase concentration of condensable vapors: the more there was sulfuric acid in the gas phase, the more hygroscopic the nucleation mode particles were. No clear dependence was found between the extremely low-volatility organics (ELVOCs) concentration and the HGF of particles of any size.

  10. Relating the hygroscopic properties of submicron aerosol to both gas- and particle-phase chemical composition in a boreal forest environment

    NASA Astrophysics Data System (ADS)

    Hong, J.; Kim, J.; Nieminen, T.; Duplissy, J.; Ehn, M.; Äijälä, M.; Hao, L. Q.; Nie, W.; Sarnela, N.; Prisle, N. L.; Kulmala, M.; Virtanen, A.; Petäjä, T.; Kerminen, V.-M.

    2015-10-01

    Measurements of the hygroscopicity of 15-145 nm particles in a boreal forest environment were conducted using two Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA) systems during the Pan-European Gas-Aerosols-climate interaction Study (PEGASOS) campaign in spring 2013. Measurements of the chemical composition of non-size segregated particles were also performed using a high-resolution aerosol mass spectrometer (HR-AMS) in parallel with hygroscopicity measurements. On average, the hygroscopic growth factor (HGF) of particles was observed to increase from the morning until afternoon. In case of accumulation mode particles, the main reasons for this behavior were increases in the ratio of sulfate to organic matter and oxidation level (O : C ratio) of the organic matter in the particle phase. Using an O : C dependent hygroscopic growth factor of organic matter (HGForg), fitted using the inverse Zdanovskii-Stokes-Robinson (ZSR) mixing rule, clearly improved the agreement between measured HGF and that predicted based on HR-AMS composition data. Besides organic oxidation level, the influence of inorganic species was tested when using the ZSR mixing rule to estimate the hygroscopic growth factor of organics in the aerosols. While accumulation and Aitken mode particles were predicted fairly well by the bulk aerosol composition data, the hygroscopicity of nucleation mode particles showed little correlation. However, we observed them to be more sensitive to the gas phase concentration of condensable vapors: the more sulfuric acid in the gas phase, the more hygroscopic the nucleation mode particles were. No clear dependence was found between the extremely low-volatility organics concentration (ELVOC) and the HGF of particles of any size.

  11. Current Mode Logic Fan Out

    2011-05-07

    Current mode logic is used in high speed timing systems for particle accelerators due to the fast rise time of the electrical signal. This software provides the necessary documentation to produce multiple copies of a single input for distribution to multiple devices. This software supports the DOE mission by providing a method for producing high speed signals in accelerator timing systems.

  12. Comparison of various wall conditionings on the reduction of H content and particle recycling in EAST

    NASA Astrophysics Data System (ADS)

    Zuo, G. Z.; Hu, J. S.; Zhen, S.; Li, J. G.; Mansfield, D. K.; Cao, B.; Wu, J. H.; Zakharov, L. E.; EAST Team

    2012-01-01

    Reductions in H content and particle recycling are important for the improvement of ion cyclotron range of frequency (ICRF) minority heating efficiency and the enhancement of plasma performance of the EAST superconducting tokamak. During recent years several techniques of surface conditioning such as baking, glow discharge cleaning/ICRF discharge cleaning, surface coatings, such as boronization, siliconization and lithium coating, have all been attempted in order to reduce the H/(H+D) ratio and particle recycling in EAST. Even though boronization and siliconization were both reasonably effective methods to improve plasma performance, lithium coatings were observed to reduce the H content and particle recycling to levels low enough to allow the attainment of enhanced plasma parameters and operating modes on EAST. For example, by accomplishing lithium coating using either vacuum evaporation or the real-time injection of fine lithium powder, the H/(H+D) ratio could be routinely decreased to about 5%, which significantly improved ICRF minority heating efficiency during the autumn campaign of 2010. Due to the reduced H/(H+D) ratio and lower particle recycling, and a reduced H-mode power threshold, improved plasma confinement and the first EAST H-mode plasma were obtained. Furthermore, with increasing accumulation of deposited lithium, several new milestones of EAST performance, such as a 6.4 s-long H-mode, a 100 s-long plasma duration and a 1 MA plasma current, were achieved in the 2010 autumn campaign.

  13. Particle exposures and infections.

    PubMed

    Ghio, A J

    2014-06-01

    Particle exposures increase the risk for human infections. Particles can deposit in the nose, pharynx, larynx, trachea, bronchi, and distal lung and, accordingly, the respiratory tract is the system most frequently infected after such exposure; however, meningitis also occurs. Cigarette smoking, burning of biomass, dust storms, mining, agricultural work, environmental tobacco smoke (ETS), wood stoves, traffic-related emissions, gas stoves, and ambient air pollution are all particle-related exposures associated with an increased risk for respiratory infections. In addition, cigarette smoking, burning of biomass, dust storms, mining, and ETS can result in an elevated risk for tuberculosis, atypical mycobacterial infections, and meningitis. One of the mechanisms for particle-related infections includes an accumulation of iron by surface functional groups of particulate matter (PM). Since elevations in metal availability are common to every particle exposure, all PM potentially contributes to these infections. Therefore, exposures to wood stove emissions, diesel exhaust, and air pollution particles are predicted to increase the incidence and prevalence of tuberculosis, atypical mycobacterial infections, and meningitis, albeit these elevations are likely to be small and detectable only in large population studies. Since iron accumulation correlates with the presence of surface functional groups and dependent metal coordination by the PM, the risk for infection continues as long as the particle is retained. Subsequently, it is expected that the cessation of exposure will diminish, but not totally reverse, the elevated risk for infection. PMID:24488331

  14. Particle transport induced by electrostatic wave fluctuations

    NASA Astrophysics Data System (ADS)

    Rosalem, K. C.; Roberto, M.; Caldas, I. L.

    2015-10-01

    Particle transport driven by electrostatic waves at the plasma edge is numerically investigated, for large aspect ratio tokamaks, by considering a kinetic model derived from guiding-center equations of motion. Initially, the transport is estimated for trajectories obtained from differential equations for a wave spectrum generated by a dominant spatial mode and three time modes. Then, in case of infinite time modes, the differential equations of motion are used to introduce a symplectic map that allows to analyze the particle transport. The particle transport barriers are observed for spatial localized dominant perturbation and infinite modes. In presence of infinite spatial modes, periodic islands arise in between chaotic trajectories at the plasma edge.

  15. Viscoelastic effects on electrokinetic particle focusing in a constricted microchannel

    PubMed Central

    Lu, Xinyu; DuBose, John; Joo, Sang Woo; Qian, Shizhi

    2015-01-01

    Focusing suspended particles in a fluid into a single file is often necessary prior to continuous-flow detection, analysis, and separation. Electrokinetic particle focusing has been demonstrated in constricted microchannels by the use of the constriction-induced dielectrophoresis. However, previous studies on this subject have been limited to Newtonian fluids only. We report in this paper an experimental investigation of the viscoelastic effects on electrokinetic particle focusing in non-Newtonian polyethylene oxide solutions through a constricted microchannel. The width of the focused particle stream is found NOT to decrease with the increase in DC electric field, which is different from that in Newtonian fluids. Moreover, particle aggregations are observed at relatively high electric fields to first form inside the constriction. They can then either move forward and exit the constriction in an explosive mode or roll back to the constriction entrance for further accumulations. These unexpected phenomena are distinct from the findings in our earlier paper [Lu et al., Biomicrofluidics 8, 021802 (2014)], where particles are observed to oscillate inside the constriction and not to pass through until a chain of sufficient length is formed. They are speculated to be a consequence of the fluid viscoelasticity effects. PMID:25713690

  16. ITER helium ash accumulation

    SciTech Connect

    Hogan, J.T.; Hillis, D.L.; Galambos, J.; Uckan, N.A. ); Dippel, K.H.; Finken, K.H. . Inst. fuer Plasmaphysik); Hulse, R.A.; Budny, R.V. . Plasma Physics Lab.)

    1990-01-01

    Many studies have shown the importance of the ratio {upsilon}{sub He}/{upsilon}{sub E} in determining the level of He ash accumulation in future reactor systems. Results of the first tokamak He removal experiments have been analysed, and a first estimate of the ratio {upsilon}{sub He}/{upsilon}{sub E} to be expected for future reactor systems has been made. The experiments were carried out for neutral beam heated plasmas in the TEXTOR tokamak, at KFA/Julich. Helium was injected both as a short puff and continuously, and subsequently extracted with the Advanced Limiter Test-II pump limiter. The rate at which the He density decays has been determined with absolutely calibrated charge exchange spectroscopy, and compared with theoretical models, using the Multiple Impurity Species Transport (MIST) code. An analysis of energy confinement has been made with PPPL TRANSP code, to distinguish beam from thermal confinement, especially for low density cases. The ALT-II pump limiter system is found to exhaust the He with maximum exhaust efficiency (8 pumps) of {approximately}8%. We find 1<{upsilon}{sub He}/{upsilon}{sub E}<3.3 for the database of cases analysed to date. Analysis with the ITER TETRA systems code shows that these values would be adequate to achieve the required He concentration with the present ITER divertor He extraction system.

  17. Test Plan - Solids Accumulation Scouting Studies

    SciTech Connect

    Duignan, M. R.; Steeper, T. J.; Steimke, J. L.; Fowley, M. D.

    2012-05-10

    This plan documents the highlights of the Solids Accumulations Scouting Studies test; a project, from Washington River Protection Solutions (WRPS), that began on February 1, 2012. During the last 12 weeks considerable progress has been made to design and plan methods that will be used to estimate the concentration and distribution of heavy fissile solids in accumulated solids in the Hanford double-shell tank (DST) 241-AW-105 (AW-105), which is the primary goal of this task. This DST will be one of the several waste feed delivery staging tanks designated to feed the Pretreatment Facility (PTF) of the Waste Treatment and Immobilization Plant (WTP). Note that over the length of the waste feed delivery mission AW-105 is currently identified as having the most fill empty cycles of any DST feed tanks, which is the reason for modeling this particular tank. At SRNL an existing test facility, the Mixing Demonstration Tank, which will be modified for the present work, will use stainless steel particles in a simulant that represents Hanford waste to perform mock staging tanks transfers that will allow solids to accumulate in the tank heel. The concentration and location of the mock fissile particles will be measured in these scoping studies to produce information that will be used to better plan larger scaled tests. Included in these studies is a secondary goal of developing measurement methods to accomplish the primary goal. These methods will be evaluated for use in the larger scale experiments. Included in this plan are the several pretest activities that will validate the measurement techniques that are currently in various phases of construction. Aspects of each technique, e.g., particle separations, volume determinations, topographical mapping, and core sampling, have been tested in bench-top trials, as discussed herein, but the actual equipment to be employed during the full test will need evaluation after fabrication and integration into the test facility.

  18. Ultrafine particles, and PM 2.5 generated from cooking in homes

    NASA Astrophysics Data System (ADS)

    Wan, Man-Pun; Wu, Chi-Li; Sze To, Gin-Nam; Chan, Tsz-Chun; Chao, Christopher Y. H.

    2011-11-01

    Exposure to airborne particulate matters (PM) emitted during cooking can lead to adverse health effects. An understanding of the exposure to PM during cooking at home provides a foundation for the quantification of possible health risks. The concentrations of airborne particles covering the ultrafine (14.6-100 nm) and accumulation mode (100-661.2 nm) size ranges and PM 2.5 (airborne particulate matters smaller than 2.5 μm in diameter) during and after cooking activities were measured in 12 naturally ventilated, non-smoking homes in Hong Kong, covering a total of 33 cooking episodes. The monitored homes all practiced Chinese-style cooking. Cooking elevated the average number concentrations of ultrafine particles (UFPs) and accumulation mode particles (AMPs) by 10 fold from the background level in the living room and by 20-40 fold in the kitchen. PM 2.5 mass concentrations went up to the maximum average of about 160 μg m -3 in the kitchen and about 60 μg m -3 in the living room. Cooking emitted particles dispersed quickly from the kitchen to the living room indicating that the health impact is not limited to occupants in the kitchen. Particle number and mass concentrations remained elevated for 90 min in the kitchen and for 60 min in the living room after cooking. Particles in cooking emissions were mainly in the ultrafine size range in terms of the number count while AMPs contributed to at least 60% of the surface area concentrations in the kitchen and 73% in the living room. This suggests that AMPs could still be a major health concern since the particle surface area concentration is suggested to have a more direct relationship with inhalation toxicity than with number concentration. Particle number concentration (14.6-661.2 nm) in the living room was about 2.7 times that in the outdoor environment, suggesting that better ventilation could help reduce exposure.

  19. Natural Mode Entanglement as a Resource for Quantum Communication

    SciTech Connect

    Heaney, Libby; Vedral, Vlatko

    2009-11-13

    Natural particle-number entanglement resides between spatial modes in coherent ultracold atomic gases. However, operations on the modes are restricted by a superselection rule that forbids coherent superpositions of different particle numbers. This seemingly prevents mode entanglement being used as a resource for quantum communication. In this Letter, we demonstrate that mode entanglement of a single massive particle can be used for dense coding and quantum teleportation despite the superselection rule. In particular, we provide schemes where the dense coding linear photonic channel capacity is reached without a shared reservoir and where the full quantum channel capacity is achieved if both parties share a coherent particle reservoir.

  20. Guiding center equations for ideal magnetohydrodynamic modes

    SciTech Connect

    White, R. B.

    2013-04-15

    Guiding center simulations are routinely used for the discovery of mode-particle resonances in tokamaks, for both resistive and ideal instabilities and to find modifications of particle distributions caused by a given spectrum of modes, including large scale avalanches during events with a number of large amplitude modes. One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through {delta}B-vector={nabla} Multiplication-Sign ({xi}-vector Multiplication-Sign B-vector), however, perturbs the magnetic topology, introducing extraneous magnetic islands in the field. A proper treatment of an ideal perturbation involves a full Lagrangian displacement of the field due to the perturbation and conserves magnetic topology as it should. In order to examine the effect of ideal magnetohydrodynamic modes on particle trajectories, the guiding center equations should include a correct Lagrangian treatment. Guiding center equations for an ideal displacement {xi}-vector are derived which preserve the magnetic topology and are used to examine mode particle resonances in toroidal confinement devices. These simulations are compared to others which are identical in all respects except that they use the linear representation for the field. Unlike the case for the magnetic field, the use of the linear field perturbation in the guiding center equations does not result in extraneous mode particle resonances.

  1. Guiding Center Equations for Ideal Magnetohydrodynamic Modes

    SciTech Connect

    Roscoe B. White

    2013-02-21

    Guiding center simulations are routinely used for the discovery of mode-particle resonances in tokamaks, for both resistive and ideal instabilities and to find modifications of particle distributions caused by a given spectrum of modes, including large scale avalanches during events with a number of large amplitude modes. One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through δ~B = ∇ X (ξ X B) however perturbs the magnetic topology, introducing extraneous magnetic islands in the field. A proper treatment of an ideal perturbation involves a full Lagrangian displacement of the field due to the perturbation and conserves magnetic topology as it should. In order to examine the effect of ideal magnetohydrodynamic modes on particle trajectories the guiding center equations should include a correct Lagrangian treatment. Guiding center equations for an ideal displacement ξ are derived which perserve the magnetic topology and are used to examine mode particle resonances in toroidal confinement devices. These simulations are compared to others which are identical in all respects except that they use the linear representation for the field. Unlike the case for the magnetic field, the use of the linear field perturbation in the guiding center equations does not result in extraneous mode particle resonances.

  2. Particle jumps in structural glasses.

    PubMed

    Ciamarra, Massimo Pica; Pastore, Raffaele; Coniglio, Antonio

    2016-01-14

    Particles in structural glasses rattle around temporary equilibrium positions, that seldom change through a process which is much faster than the relaxation time, known as particle jump. Since the relaxation of the system is due to the accumulation of many such jumps, it could be possible to connect the single particle short time motion to the macroscopic relaxation by understanding the features of the jump dynamics. Here we review recent results in this research direction, clarifying the features of particle jumps that have been understood and those that are still under investigation, and examining the role of particle jumps in different theories of the glass transition. PMID:26481331

  3. Particle fracture in high-volume-fraction ceramic-reinforced metals: Governing parameters and implications for composite failure

    NASA Astrophysics Data System (ADS)

    Hauert, Aude; Rossoll, Andreas; Mortensen, Andreas

    2009-11-01

    Weibull parameters of angular alumina particles are determined from experimental tensile test data on high-ceramic-content metal matrix composites using a micromechanical model that accounts for internal damage in the form of particle cracking, the dominant damage mode in these composites. The fraction of broken particles is assessed from the drop of Young's modulus and particle fracture is assumed to be stress controlled. Two extreme load-sharing modes, namely a purely local and a global load-sharing mode, are considered to account for the load redistribution due to particle fracture. Consistent powder strength parameters can be thus "back-calculated" for particles that are embedded in different Al-Cu matrices. On the other hand, this calculation fails for pure Al matrix composites, which exhibit a much larger strain to failure than Al-Cu matrix composites. It is shown that for Al matrix composites, the role of plastic (composite) strain on particle fracture constitutes a second parameter governing particle damage. This finding is rationalized by particle-particle interactions in these tightly packed ceramic particle-reinforced composites, and by the increase of matrix stress heterogeneity that is brought with increasing plastic strain. Failure of the alloyed matrix composites is well described by the (lower bound) local load-sharing micromechanical model, which predicts a catastrophic failure due to an avalanche of damage. The same model predicts failure of pure aluminium matrix composites to occur at the onset of tensile instability, also in agreement with experimental results once the role of plastic strain on damage accumulation is accounted for.

  4. Influences of traffic volumes and wind speeds on ambient ultrafine particle levels—Observations at a highway electronic toll collection (ETC) lane

    NASA Astrophysics Data System (ADS)

    Cheng, Yu-Hsiang; Li, Yi-Sheng

    2011-01-01

    The levels of ultrafine particles (UFPs) and their size distributions on a highway electronic toll collection (ETC) lane were measured from October 30 to November 1 and November 5 to November 6, 2008. The hourly UFP levels measured at the highway ETC lane were 1.3 × 10 4-1.9 × 10 5 particles cm -3 (mean = 9.4 × 10 4 particles cm -3). Compared with urban UFP levels, average UFP levels at the highway ETC lane were about 5-10 times higher than those previously measured in urban areas, indicating that a considerable amount of UFPs were exhausted from vehicles. At the highway ETC lane, the average UFP number size distribution had a dominant mode at about 10 nm and a minor mode at about 33 nm. Measurement results indicate that nucleation mode particles remained at relatively high levels compared to Aitken mode and accumulation mode particles at the highway ETC lane. This study identifies the impacts of traffic volumes and wind speeds on ambient UFP levels. Measurement results show that the elevated UFP levels resulting from traffic volume decreased exponentially as wind speed increased on the highway when wind speed was <2.0 m s -1. However, the elevated UFP levels resulting from traffic volume increased slightly when wind speed was >2.0 m s -1 due to local turbulent mixing causes UFPs at high wind speeds. According to measurement results, high levels of UFP were observed at low wind speeds and under high traffic volumes.

  5. Noise Reduction by Signal Accumulation

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2006-01-01

    The aim of this paper is to show how the noise reduction by signal accumulation can be accomplished with a data acquisition system. This topic can be used for student projects. In many cases, the noise reduction is an unavoidable part of experimentation. Several techniques are known for this purpose, and among them the signal accumulation is the…

  6. Breathing Mode in Complex Plasmas

    NASA Astrophysics Data System (ADS)

    Fujioka, K.; Henning, C.; Ludwig, P.; Bonitz, M.; Melzer, A.; Vitkalov, S.

    2007-11-01

    The breathing mode is a fundamental normal mode present in Coulomb systems, and may have utility in identifying particle charge and the Debye length of certain systems. The question remains whether this mode can be extended to strongly coupled Yukawa balls [1]. These systems are characterized by particles confined within a parabolic potential well and interacting through a shielded Coulomb potential [2,3]. The breathing modes for a variety of systems in 1, 2, and 3 dimensions are computed by solving the eigenvalue problem given by the dynamical (Hesse) matrix. These results are compared to theoretical investigations that assume a strict definition for a breathing mode within the system, and an analysis is made of the most fitting model to utilize in the study of particular systems of complex plasmas [1,4]. References [1] T.E. Sheridan, Phys. of Plasmas. 13, 022106 (2006)[2] C. Henning et al., Phys. Rev. E 74, 056403 (2006)[3] M. Bonitz et al., Phys. Rev. Lett. 96, 075001 (2006)[4] C. Henning et al., submitted for publication

  7. Number concentration and size of particles in urban air: effects on spirometric lung function in adult asthmatic subjects.

    PubMed Central

    Penttinen, P; Timonen, K L; Tiittanen, P; Mirme, A; Ruuskanen, J; Pekkanen, J

    2001-01-01

    Daily variations in ambient particulate air pollution are associated with variations in respiratory lung function. It has been suggested that the effects of particulate matter may be due to particles in the ultrafine (0.01-0.1 microm) size range. Because previous studies on ultrafine particles only used self-monitored peak expiratory flow rate (PEFR), we assessed the associations between particle mass and number concentrations in several size ranges measured at a central site and measured (biweekly) spirometric lung function among a group of 54 adult asthmatics (n = 495 measurements). We also compared results to daily morning, afternoon, and evening PEFR measurements done at home (n = 7,672-8,110 measurements). The median (maximum) 24 hr number concentrations were 14,500/cm(3) (46,500/cm(3)) ultrafine particles and 800/cm(3) (2,800/cm(3)) accumulation mode (0.1-1 microm) particles. The median (maximum) mass concentration of PM(2.5) (particulate matter < 2.5 microm) and PM(10) (particulate matter < 10 microm in aerodynamic diameter) were 8.4 microg/m(3) (38.3 microg/m(3)) and 13.5 microg/m(3) (73.7 microg/m(3)), respectively. The number of accumulation mode particles was consistently inversely associated with PEFR in spirometry. Inverse, but nonsignificant, associations were observed with ultrafine particles, and no associations were observed with large particles (PM(10)). Compared to the effect estimates for self-monitored PEFR, the effect estimates for spirometric PEFR tended to be larger. The standard errors were also larger, probably due to the lower number of spirometric measurements. The present results support the need to monitor the particle number and size distributions in urban air in addition to mass. PMID:11335178

  8. Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

    NASA Astrophysics Data System (ADS)

    Salma, I.; Borsós, T.; Weidinger, T.; Aalto, P.; Hussein, T.; Dal Maso, M.; Kulmala, M.

    2010-06-01

    Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6-1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8×103 to 29×103 cm-3 with a yearly median of 11.8×103 cm-3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79±6)%. Daily average number concentrations in various size fractions and contribution of ultrafine particles to the total particle number showed no seasonal dependency. Monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. Median diameters of the Aitken and accumulation modes were shifted to larger values before nucleation started and over the growth process, which can be related to the presence of aged aerosol under the conditions that favour nucleation and growth. Particle concentrations were usually increased substantially after nucleations. Overall mean and standard deviation of the nucleation mode number concentrations were (10.4±2.8)×103 cm-3. Mean ratio and standard deviation of the nucleation mode number concentration to the total particle number concentration that was averaged for two hours just before the formation was detected was 2.3±1.1. Nucleation unambiguously occurred on 83 days, which represent 27% of all relevant days. Its frequency showed a remarkable seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. Formation

  9. Control of helium accumulation by fishbones

    SciTech Connect

    Varadarajan, V.; Miley, G.H.

    1989-01-01

    It is well known that fishbone oscillations occur in the tokamak plasma at high {epsilon}{beta}p and in the presence of large hot trapped particle population. We adopt and extend the formalism of Chen et al. to analyze the trapped hot ion induced fishbones in the ITER-type plasma. Using the familiar assumptions like large assumptions like large aspect ratio and low beta, we considered the stability of the trapped-ion induced internal kink mode in the presence of alphas and one other species of hot ions.

  10. Accumulated damage process of thermal sprayed coating under rolling contact by acoustic emission technique

    NASA Astrophysics Data System (ADS)

    Xu, Jia; Zhou, Zhen-yu; Piao, Zhong-yu

    2016-07-01

    The accumulated damage process of rolling contact fatigue (RCF) of plasma-sprayed coatings was investigated. The influences of surface roughness, loading condition, and stress cycle frequency on the accumulated damage status of the coatings were discussed. A ball-ondisc machine was employed to conduct RCF experiments. Acoustic emission (AE) technique was introduced to monitor the RCF process of the coatings. AE signal characteristics were investigated to reveal the accumulated damage process. Result showed that the polished coating would resist the asperity contact and remit accumulated damage. The RCF lifetime would then extend. Heavy load would aggravate the accumulated damage status and induce surface fracture. Wear became the main failure mode that reduced the RCF lifetime. Frequent stress cycle would aggravate the accumulated damage status and induce interface fracture. Fatigue then became the main failure mode that also reduced the RCF lifetime.

  11. A new method for polyhydroxyalkanoate (PHA) accumulating bacteria selection under physical selective pressure.

    PubMed

    Chen, Zhiqiang; Guo, Zirui; Wen, Qinxue; Huang, Long; Bakke, Rune; Du, Maoan

    2015-01-01

    An aerobic dynamic discharge (ADD) process involving physical selective pressure to favor the accumulation of polyhydroxyalkanoates (PHAs) accumulating bacteria in microbial mixed cultures (MMCs) is proposed and evaluated in this study. Sequencing batch reactor PHA production in the ADD mode was compared to the conventional aerobic dynamic feeding (ADF) mode. Results showed that the cultures selected under the ADD mode showed a better PHA producing potential than ADF mode cultures in terms of both maximum PHA content and selection time, explained by altered physical selective pressure. The maximum PHA content of 74.16 (± 0.03)% and PHA yield of 0.72 (± 0.07) C mol PHA/C mol Ac were achieved after 30 days of the ADD operation, which were much higher than those obtained under the same organic loading rate in the ADF operation. The ADD mode is a promising method for quick selection of a strong-PHA accumulating culture. PMID:25450834

  12. Gypsum accumulation on carbonate stone

    USGS Publications Warehouse

    McGee, E.S.; Mossotti, V.G.

    1992-01-01

    The accumulation of gypsum on carbonate stone has been investigated through exposure of fresh samples of limestone and marble at monitored sites, through examination of alteration crusts from old buildings and through laboratory experiments. Several factors contribute to gypsum accumulation on carbonate stone. Marble or limestone that is sheltered from direct washing by rain in an urban environment with elevated pollution levels is likely to accumulate a gypsum crust. Crust development may be enhanced if the stone is porous or has an irregular surface area. Gypsum crusts are a surficial alteration feature; gypsum crystals form at the pore opening-air interface, where evaporation is greatest.

  13. Source apportionment of ambient fine particle size distribution using positive matrix factorization in Erfurt, Germany

    PubMed Central

    Yue, Wei; Stölzel, Matthias; Cyrys, Josef; Pitz, Mike; Heinrich, Joachim; Kreyling, Wolfgang G.; Wichmann, H.-Erich; Peters, Annette; Wang, Sheng; Hopke, Philip K.

    2008-01-01

    Particle size distribution data collected between September 1997 and August 2001 in Erfurt, Germany were used to investigate the sources of ambient particulate matter by positive matrix factorization (PMF). A total of 29,313 hourly averaged particle size distribution measurements covering the size range of 0.01 to 3.0 μm were included in the analysis. The particle number concentrations (cm−3) for the 9 channels in the ultrafine range, and mass concentrations (ng m−3) for the 41 size bins in the accumulation mode and particle up to 3 μm in aerodynamic diameter were used in the PMF. The analysis was performed separately for each season. Additional analyses were performed including calculations of the correlations of factor contributions with gaseous pollutants (O3, NO, NO2, CO and SO2) and particle composition data (sulfate, organic carbon and elemental carbon), estimating the contributions of each factor to the total number and mass concentration, identifying the directional locations of the sources using the conditional probability function, and examining the diurnal patterns of factor scores. These results were used to assist in the interpretation of the factors. Five factors representing particles from airborne soil, ultrafine particles from local traffic, secondary aerosols from local fuel combustion, particles from remote traffic sources, and secondary aerosols from multiple sources were identified in all seasons. PMID:18433834

  14. Dual-Mode Combustion

    NASA Technical Reports Server (NTRS)

    Goyne, Christopher P.; McDaniel, James C.

    2002-01-01

    The Department of Mechanical and Aerospace Engineering at the University of Virginia has conducted an investigation of the mixing and combustion processes in a hydrogen fueled dual-mode scramjet combustor. The experiment essentially consisted of the "direct connect" continuous operation of a Mach 2 rectangular combustor with a single unswept ramp fuel injector. The stagnation enthalpy of the test flow simulated a flight Mach number of 5. Measurements were obtained using conventional wall instrumentation and laser based diagnostics. These diagnostics included, pressure and wall temperature measurements, Fuel Plume Imaging (FPI) and Particle Image Velocimetry (PIV). A schematic of the combustor configuration and a summary of the measurements obtained are presented. The experimental work at UVa was parallel by Computational Fluid Dynamics (CFD) work at NASA Langley. The numerical and experiment results are compared in this document.

  15. Edge Mode Coupling within a Plasmonic Nanoparticle.

    PubMed

    Schmidt, Franz-Philipp; Ditlbacher, Harald; Hohenau, Andreas; Hohenester, Ulrich; Hofer, Ferdinand; Krenn, Joachim R

    2016-08-10

    The coupling of plasmonic nanoparticles can strongly modify their optical properties. Here, we show that the coupling of the edges within a single rectangular particle leads to mode splitting and the formation of bonding and antibonding edge modes. We are able to unambiguously designate the modes due to the high spatial resolution of electron microscopy-based electron energy loss spectroscopy and the comparison with numerical simulations. Our results provide simple guidelines for the interpretation and the design of plasmonic mode spectra. PMID:27427962

  16. 40 CFR Table F-3 to Subpart F of... - Critical Parameters of Idealized Ambient Particle Size Distributions

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Ambient Particle Size Distributions Idealized Distribution Fine Particle Mode MMD (µm) Geo. Std. Dev. Conc. (µg/m3) Coarse Particle Mode MMD (µm) Geo. Std. Dev. Conc. (µg/m3) PM 2.5/PM 10 Ratio FRM...

  17. 40 CFR Table F-3 to Subpart F of... - Critical Parameters of Idealized Ambient Particle Size Distributions

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Ambient Particle Size Distributions Idealized Distribution Fine Particle Mode MMD (µm) Geo. Std. Dev. Conc. (µg/m 3) Coarse Particle Mode MMD (µm) Geo. Std. Dev. Conc. (µg/m 3) PM 2.5/PM 10 Ratio FRM...

  18. Accumulation of radionuclides from radioactive substrata by some micromycetes.

    PubMed

    Zhdanova, N N; Redchits, T I; Zheltonozhsky, V A; Sadovnikov, L V; Gerzabek, M H; Olsson, S; Strebl, F; Mück, K

    2003-01-01

    Overgrowing (interaction) and dissolution of intact and milled hot particles by various micromycetes were studied under laboratory conditions. Hot particles used for the investigation originated from the Chernobyl accident release and atomic bomb testing sites. The micromycetes investigated were mitosporic fungi mainly isolated from the Chernobyl site and vicinity. Most of the fungal species and strains showed a tendency to grow towards the hot particle, overgrow it and dissolve it after prolonged contact. The accumulation (absorption and adsorption) of radionuclides from intact hot particles was generally more intensive for (152)Eu than for (137)Cs by a factor of about 2.6-134, while in experiments with milled samples the (152)Eu and (137)Cs accumulation was similar, except for some fungal species, which showed higher (152)Eu than (137)Cs sorption. It could be shown that the main factors influencing Cs and Eu accumulation in fungi are: fungal species and strains and the size and composition of the hot particle. PMID:12660044

  19. Manganese As a Metal Accumulator

    EPA Science Inventory

    Manganese deposits in water distribution systems accumulate metals, radionuclides and oxyanions by a combination of surface complexation, adsorption and solid substitution, as well as a combination of oxidation followed by manganese reduction and sorption of the oxidized constitu...

  20. Evidence accumulation for spatial reasoning

    NASA Technical Reports Server (NTRS)

    Matsuyama, T.; Hwang, V. S. S.; Davis, L. S.

    1984-01-01

    The evidence accumulation proces of an image understanding system is described enabling the system to perform top-down(goal-oriented) picture processing as well as bottom-up verification of consistent spatial relations among objects.

  1. SAMPEX Spin Stabilized Mode

    NASA Technical Reports Server (NTRS)

    Tsai, Dean C.; Markley, F. Landis; Watson, Todd P.

    2008-01-01

    The Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), the first of the Small Explorer series of spacecraft, was launched on July 3, 1992 into an 82' inclination orbit with an apogee of 670 km and a perigee of 520 km and a mission lifetime goal of 3 years. After more than 15 years of continuous operation, the reaction wheel began to fail on August 18,2007. With a set of three magnetic torquer bars being the only remaining attitude actuator, the SAMPEX recovery team decided to deviate from its original attitude control system design and put the spacecraft into a spin stabilized mode. The necessary operations had not been used for many years, which posed a challenge. However, on September 25, 2007, the spacecraft was successfully spun up to 1.0 rpm about its pitch axis, which points at the sun. This paper describes the diagnosis of the anomaly, the analysis of flight data, the simulation of the spacecraft dynamics, and the procedures used to recover the spacecraft to spin stabilized mode.

  2. Coherent Modes in the Edge of DIII--D H--modes

    NASA Astrophysics Data System (ADS)

    Moyer, R. A.; Lehmer, R.; Boedo, J. A.; Rhodes, T. L.; Rettig, C. L.; Doyle, E. J.; Watkins, J. G.; Groebner, R. J.; Burrell, K. H.

    1997-11-01

    Electrostatic fluctuations in the edge of DIII--D H--modes are often characterized by the presense of a large amplitude, coherent or quasi-coherent mode (f=50--60 kHz; δf=5--20 kHz). This mode is similar to coherent modes in the edge of ohmic discharges in TEXT(Tsui, et al., Phys. Rev. Lett. 70) (1993) 1565. and has also been seen in the edge of H--modes in PBX-M.(Tynan et al., Phys. Plasmas 1) (1994) 3301. The mode is localized to a narrow radial extent just inside the separatrix. In ohmic H--modes, the ``mode'' is a quasi-coherent, localized burst of turbulence. In beam heated discharges, the mode is coherent and dominates the power spectra for both density and potential fluctuations after onsetting 10--30 ms into the H--mode phase. In DIII--D, this mode directly drives particle and convective heat fluxes. Mode characteristics and plasma conditions at onset of the mode will be compared with theoretical predictions of such modes.

  3. Emissions of Trace Gases and Particles from Two Ships in the Southern Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Sinha, Parikhit; Hobbs, Peter V.; Yokelson, Robert J.; Christian, Ted J.; Kirchstetter, Thomas W.; Bruintjes, Roelof

    2003-01-01

    Measurements were made of the emissions of particles and gases from two diesel-powered ships in the southern Atlantic Ocean off the coast of Namibia. The measurements are used to derive emission factors from ships of three species not reported previously, namely, black carbon, accumulation-mode particles, and cloud condensation nuclei (CCN), as well as for carbon dioxide, carbon monoxide (CO), methane (CH4), non-methane hydrocarbons, sulfur dioxide (SO2), nitrogen oxides (NOx), and condensation nuclei. The effects of fuel grade and engine power on ship emissions are discussed. The emission factors are combined with fuel usage data to obtain estimates of global annual emissions of various particles and gases from ocean-going ships. Global emissions of black carbon, accumulation- mode particles, and CCN from ocean-going ships are estimated to be 19-26 Gg yr(sup -1), (4.4-6.1) x 10(exp 26) particles yr(sup -1), and (1.0-1.5) x l0(exp 26) particles yr(sup -1), respectively. Black carbon emissions from ocean-going ships are approximately 0.2% of total anthropogenic emissions. Emissions of NOx and SO2 from ocean-going ships are approximately 10-14% and approximately 3-4%, respectively, of the total emissions of these species from the burning of fossil fuels, and approximately 40% and approximately 70%, respectively, of the total emissions of these species from the burning of biomass. Global annual emissions of CO and CH4 from ocean-going ships are approximately 2% and approximately 2-5%, respectively, of natural oceanic emissions of these species.

  4. Seasonal and diurnal cycling of aerosol particles in and above the canopy in the Amazon rain forest

    NASA Astrophysics Data System (ADS)

    Ditas, Florian; Pöhlker, Christopher; Barbosa, Henrique; Brito, Joel; Chi, Xuguang; Krüger, Mira L.; Moran, Daniel; Saturno, Jorge; Su, Hang; Ocimar Manzi, Antonio; Artaxo, Paulo; Pöschl, Ulrich; Andreae, Meinrat O.

    2015-04-01

    The Amazonian rain forest is one of the few continental regions, providing the opportunity to study pristine aerosols approximating a pre-industrial atmosphere. During the wet season, the ambient aerosol is usually unaffected by anthropogenic emission and dominated by a biosphere-atmosphere exchange. In contrast, during the dry season, anthropogenic pollution events (e.g., biomass burning) of regional and/or global character are observed. We will present measurements carried out at a remote research facility in the Amazonian rain forest (ATTO site, S 2° 08' 45'' W 59° 00' 20") approximately 150 km northeast of Manaus. The ATTO site is equipped with a variety of instruments to characterize microphysical and optical particle properties (i.e., particle number size distribution, total particle number concentration, BC mass, scattering coefficients, and chemical composition), which can be operated at two different inlet lines to investigate particles below (5 m) and above canopy (60 m). Since June 2014 a continuous data set of simultaneous particle number size distribution measurements below and above canopy is being collected covering nucleation to coarse mode sizes. The observed particle number size distributions show a pronounced diurnal cycle throughout all size ranges. The number concentration of Aitken and accumulation mode particles exhibits distinct minima before sunrise and a 'growth-like' behavior during daytime, while coarse mode particles show a rather broad minimum and gradual increase during daytime with maximum concentration during nighttime. As already reported by earlier studies, textbook-like new particle formation and growth is not observed in the Amazonian rain forest. Nevertheless, short particle bursts in the nucleation mode size range are regularly observed and show highest abundance in the first half of the night as well as a minimum during daytime. Simultaneous measurements below and above canopy show generally similar results indicating well

  5. Upgraded cavities for the positron accumulator ring of the APS

    SciTech Connect

    Kang, Y.W.; Jiang, X.; Mangra, D.

    1997-08-01

    Upgraded versions of cavities for the APS positron accumulator ring (PAR) have been built and are being tested. Two cavities are in the PAR: a fundamental 9.8-MHz cavity and a twelfth harmonic 117.3-MHz cavity. Both cavities have been manufactured for higher voltage operation with improved Q-factors, reliability, and tuning capability. Both cavities employ current-controlled ferrite tuners for control of the resonant frequency. The harmonic cavity can be operated in either a pulsed mode or a CW mode. The rf properties of the cavities are presented.

  6. Hygroscopic growth of urban aerosol particles in Beijing (China) during wintertime: a comparison of three experimental methods

    NASA Astrophysics Data System (ADS)

    Meier, J.; Wehner, B.; Massling, A.; Birmili, W.; Nowak, A.; Gnauk, T.; Brüggemann, E.; Herrmann, H.; Min, H.; Wiedensohler, A.

    2009-09-01

    The hygroscopic properties of atmospheric aerosols are highly relevant for the quantification of radiative effects in the atmosphere, but also of interest for the assessment of particle health effects upon inhalation. This article reports measurements of aerosol particle hygroscopicity in the highly polluted urban atmosphere of Beijing, China in January 2005. The meteorological conditions corresponded to a relatively cold and dry atmosphere. Three different methods were used: 1) A combination of Humidifying Differential Mobility Particle Sizer (H-DMPS) and Twin Differential Mobility Particle Sizer (TDMPS) measurements, 2) A Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA), and 3) A simplistic solubility model fed by chemical particle composition determined from Micro Orifice Uniform Deposit Impactor (MOUDI) samples. From the H-DMPS and TDMPS particle number size distributions, a size-resolved descriptive hygroscopic growth factor (DHGF) was determined for the relative humidities (RH) 55%, 77% and 90%, and particle diameters between 30 and 400 nm. In Beijing, the highest DHGFs were observed for accumulation mode particles, 1.40 (±0.03) at 90% RH. DHGF decreased significantly with particle size, reaching 1.04 (±0.15) at 30 nm. H-TDMA data also suggest a decrease in growth factor towards the biggest particles investigated (350 nm), associated with an increasing fraction of nearly hydrophobic particles. The agreement between the H-DMPS/TDMPS and H-TDMA methods was satisfactory in the accumulation mode size range (100-400 nm). In the Aitken mode range (<100 nm), the H-DMPS/TDMPS method yielded growth factors lower by up to 0.1 at 90% RH. The application of the solubility model based on measured chemical composition clearly reproduced the size-dependent trend in hygroscopic particle growth observed by the other methods. In the case of aerosol dominated by inorganic ions, the composition-derived growth factors tended to agree (± 0.05) or underestimate (up to

  7. Possible evidence of new particle formation and its impact on cloud microphysics from airborne measurements over Bay of Bengal

    NASA Astrophysics Data System (ADS)

    Deshpande, C. G.; Bhalwankar, Rohini; Padmakumari, B.; Maheskumar, R. S.; Axisa, Duncan; Kulkarni, J. R.

    2014-04-01

    Airborne measurements conducted under a special mission over Bay of Bengal (BoB) during the CAIPEEX (Cloud Aerosol Interaction and Precipitation Enhancement EXperiment) in 2011 were analyzed in the present study. Research flights were carried out on 19 and 20 October, 2011 (referred as RF1 and RF2), in the region over BoB, which was influenced by a depression to evaluate the aerosol-cloud interactions over marine environment. The increased concentration of aitken/accumulation mode particles was observed at 500 m above sea surface level over the ocean after the passage of the depression. The source of these particles and their subsequent growth during RF1 at about 200 km from coastline has been attributed to (i) increased production of aerosols due to oxidation of dimethyl sulfide (DMS) because of upwelling of the deep ocean water during the depression and (ii) anthropogenic aerosols transported from inland. Moreover, measurements of accumulation and coarse mode particles with diameter ranging from 0.1 to 3 μm and cloud droplets in the range 3 to 47 μm show systematic growth associated with cloud microphysical/rain formation process. On the other hand, no such evidence of increasing particle concentration and growth has been observed at about 60 km from coastline towards southeast during RF2. Evidently, the rain event observed during the night hours of 19 October caused the washout and scavenging of aerosols which contributed towards the decreased aerosol concentration observed near the coast.

  8. Characteristics of new particle formation events in Nanjing, China: Effect of water-soluble ions

    NASA Astrophysics Data System (ADS)

    An, Junlin; Wang, Honglei; Shen, Lijuan; Zhu, Bin; Zou, Jianan; Gao, Jinhui; Kang, Hanqing

    2015-05-01

    New particle formation (NPF) events and water-soluble ions were studied at the meteorological building on the campus of the Nanjing University of Information Science and Technology (NUIST), which is located in the western part of the Yangtze River Delta (YRD). A wide-range particle spectrometer (WPS) provided particle number size distributions between 10 nm and 10 μm, whereas water-soluble ions for particles with diameters between 10 nm and 18 μm were measured using a 13-stage Nano-MOUDI aerosol sampler and 850 professional Ion Chromatography (IC). Additionally, meteorological data, trace gas concentrations and mass concentration were recorded. Ten NPF days were captured during the measurement period from 08 July to 02 August 2012. The mean aerosol number concentration, which was primarily composed of Aitken-mode particles, i.e., with diameters of 20-100 nm, was 13,664 cm-3, which was 1.9 times larger than that on non-NPF days. The results suggest that the NPF events were only slightly affected by O3, SO2, and NO2; the primary factors affecting NPF events were meteorological factors and air mass directions. NPF events were found to be favorable during the summer in the presence of high temperatures, strong radiation, low humidity, strong winds and clean air masses originating from the southeastern coast. The mean growth rate (GR), formation rate (J10), condensational sink (CS), condensing vapor rate (Q), and condensation vapor (C) were determined to be 7.6 nm h-1, 3.7 cm-3 s-1, 2.8 × 10-2 s-1, 2.9 × 106 cm-3 s-1, and 10.5 × 107 cm-3, respectively, on NPF days. The largest effects of the studied NPF events were on the mass and water-soluble ion concentrations of Aitken-mode particles, followed by nuclei-mode particles; few contributions to accumulation- and coarse-mode particles were observed. Different water-soluble ions were observed to have distinct interactions with the NPF events. The proportions of NH4+, SO42-, NO3-, K+ and Mg2+ in nuclei- and Aitken-mode

  9. Berreman mode and epsilon near zero mode.

    PubMed

    Vassant, Simon; Hugonin, Jean-Paul; Marquier, Francois; Greffet, Jean-Jacques

    2012-10-01

    In this paper, we discuss the existence of an electromagnetic mode propagating in a thin dielectric film deposited on a metallic film at the particular frequency such that the dielectric permittivity vanishes. We discuss the remarkable properties of this mode in terms of extreme subwavelength mode confinment and its potential applications. We also discuss the link between this mode, the IR absorption peak on a thin dielectric film known as Berreman effect and the surface phonon polariton mode at the air/dielectric interface. Finally, we establish a connection with the polarization shift occuring in quantum wells. PMID:23188363

  10. Edge-localized mode avoidance and pedestal structure in I-mode plasmasa)

    NASA Astrophysics Data System (ADS)

    Walk, J. R.; 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.; Snyder, P. B.; Osborne, T.; Dominguez, A.; Cziegler, I.

    2014-05-01

    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 Pnet/n ¯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 Pnet/n ¯e. This is consistent with targets for increased performance in I-mode, elevating pedestal βp 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, consistent with the observed suppression of

  11. Kinetic calculation of the resistive wall mode and fishbone-like mode instability in tokamak

    NASA Astrophysics Data System (ADS)

    Hao, G. Z.; Yang, S. X.; Liu, Y. Q.; Wang, Z. X.; Wang, A. K.; He, H. D.

    2016-06-01

    Kinetic effects of both trapped thermal and energetic particles on the resistive wall mode (RWM) and on the fishbone-like mode (FLM) are investigated in theory. Here, the trapped thermal particles include both ions and electrons. The FLM is driven by trapped energetic particles. The results demonstrate that thermal particle collisions can either stabilize or destabilize the RWM, depending on the energetic particle pressure βh . Furthermore, the critical value of βh for triggering the FLM is increased when the thermal particle contribution is taken into account. The critical value sensitively depends on the plasma collision frequency. In addition, the plasma inertia is found to have a negligible influence on the FLM.

  12. Studies of EDA H-mode and Its Relation to the Micro-stability of the Pedestal

    NASA Astrophysics Data System (ADS)

    Greenwald, M.; Boivin, R. L.; Granetz, R.; Hubbard, A.; Labombard, B.; Lin, Y.; Mazurenko, A.; Mossessian, D.; Yuh, H.; Dorland, W.; Rogers, B.

    2000-10-01

    The advantages of EDA H-modes include good energy confinement and no impurity accumulation or large ELMs. In EDA, the edge pressure gradients can be at or above the ideal ballooning limit but are not relaxed by type I ELMs; instead a continuous process, which drives particle transport in the barrier region, appears to be at work. This particle transport, which is above the levels seen in ELMfree H-modes, is caused at least in part by quasi-coherent fluctuations which are observed with reflectometry, PCI and electrostatic probes. Recent work has focussed on identifying the plasma instability which is manifested in this mode. In deuterium, the EDA is obtained most readily at q >= 3.5 and δ <= 0.3. Recent experiments in hydrogen found EDA H-modes with q as low as 2.5. The q and mi dependences are consistent with the stability criteria for resistive ballooning which is believed to be an important component of the edge turbulence. Comparisons with the linear gyrokinetic code, gs2, will also be shown.

  13. Maximum likelihood decoding analysis of Accumulate-Repeat-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    Repeat-Accumulate (RA) codes are the simplest turbo-like codes that achieve good performance. However, they cannot compete with Turbo codes or low-density parity check codes (LDPC) as far as performance is concerned. The Accumulate Repeat Accumulate (ARA) codes, as a subclass of LDPC codes, are obtained by adding a pre-coder in front of RA codes with puncturing where an accumulator is chosen as a precoder. These codes not only are very simple, but also achieve excellent performance with iterative decoding. In this paper, the performance of these codes with (ML) decoding are analyzed and compared to random codes by very tight bounds. The weight distribution of some simple ARA codes is obtained, and through existing tightest bounds we have shown the ML SNR threshold of ARA codes approaches very closely to the performance of random codes. We have shown that the use of precoder improves the SNR threshold but interleaving gain remains unchanged with respect to RA code with puncturing.

  14. Particle separation

    DOEpatents

    Moosmuller, Hans; Chakrabarty, Rajan K.; Arnott, W. Patrick

    2011-04-26

    Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

  15. Particle separation

    NASA Technical Reports Server (NTRS)

    Moosmuller, Hans (Inventor); Chakrabarty, Rajan K. (Inventor); Arnott, W. Patrick (Inventor)

    2011-01-01

    Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

  16. Strong Destabilization of Stable Modes with a Half-Frequency Associated with Chirping Geodesic Acoustic Modes in the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Ido, T.; Itoh, K.; Osakabe, M.; Lesur, M.; Shimizu, A.; Ogawa, K.; Toi, K.; Nishiura, M.; Kato, S.; Sasaki, M.; Ida, K.; Inagaki, S.; Itoh, S.-I.

    2016-01-01

    Abrupt and strong excitation of a mode has been observed when the frequency of a chirping energetic-particle driven geodesic acoustic mode (EGAM) reaches twice the geodesic acoustic mode (GAM) frequency. The frequency of the secondary mode is the GAM frequency, which is a half-frequency of the primary EGAM. Based on the analysis of spatial structures, the secondary mode is identified as a GAM. The phase relation between the secondary mode and the primary EGAM is locked, and the evolution of the growth rate of the secondary mode indicates nonlinear excitation. The results suggest that the primary mode (EGAM) contributes to nonlinear destabilization of a subcritical mode.

  17. Contrasting the Evaporation and Condensation of Water from Glassy and Amorphous Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Reid, J. P.; Bones, D. L.; Power, R.; Lienhard, D.; Krieger, U. K.

    2012-04-01

    The partitioning of water between the condensed and gas phases in atmospheric aerosol is usually assumed to occur instantaneously and to be regulated by solution thermodynamics. However, the persistence of high viscosity, glassy and amorphous aerosol to low relative humidity without crystallisation occurring is now widely recognised, suggesting that the timescale for water transport to or from the particle during condensation or evaporation may be significant. A kinetic limitation on water transport could have important implications for understanding hygroscopic growth measurements made on ambient particles, the ability of particles to act as ice nuclei or cloud condensation nuclei, the kinetics of chemical aging/heterogeneous chemistry, and the rate or condensation/evaporation of semi-volatile organic components. In this study we will report on measurements of the timescale of water transport to and from glassy aerosol and ultra-high viscosity solution droplets using aerosol optical tweezers to investigate the time-response of single particles to changes in relative humidity. As a benchmark system, mixed component aerosol particles containing sucrose and sodium chloride have been used; varying the mole fractions of the two solutes allows a wide range of solution viscosities to be studied. We will show that coarse particles can take many thousands of seconds to equilibrate in size and that the timescale correlates with the estimated bulk viscosity of the particle. We will also confirm that significant inhomogeneities in particle composition can be established during evaporation or condensation. Using the experimental data to benchmark a model for equilibration time, predictions can be made of the timescale for the equilibration of accumulation mode particles during water condensation or evaporation and these predictions will be described and their significance explored. Finally, the coalescence dynamics of highly viscous aerosol particles will be reported

  18. Dynamic radioactive particle source

    DOEpatents

    Moore, Murray E.; Gauss, Adam Benjamin; Justus, Alan Lawrence

    2012-06-26

    A method and apparatus for providing a timed, synchronized dynamic alpha or beta particle source for testing the response of continuous air monitors (CAMs) for airborne alpha or beta emitters is provided. The method includes providing a radioactive source; placing the radioactive source inside the detection volume of a CAM; and introducing an alpha or beta-emitting isotope while the CAM is in a normal functioning mode.

  19. Ecology: accumulating threats to life

    SciTech Connect

    Peterson, R.W.

    1980-04-01

    The accumulating impacts of toxic materials like polychloridnated bephenyls (PCBs), acid rain, deforestation in the Amazon River Basin, and nuclear energy are examined as life-threatening actions that the public must recognize. Immediate action is needed to abandon destructive human activities and search out those life-supporting choices which will replace immediate gratification with long-range benefits. (DCK)

  20. Pensions and Household Wealth Accumulation

    ERIC Educational Resources Information Center

    Engelhardt, Gary V.; Kumar, Anil

    2011-01-01

    Economists have long suggested that higher private pension benefits "crowd out" other sources of household wealth accumulation. We exploit detailed information on pensions and lifetime earnings for older workers in the 1992 wave of the Health and Retirement Study and employ an instrumental-variable (IV) identification strategy to estimate…

  1. List mode multichannel analyzer

    DOEpatents

    Archer, Daniel E.; Luke, S. John; Mauger, G. Joseph; Riot, Vincent J.; Knapp, David A.

    2007-08-07

    A digital list mode multichannel analyzer (MCA) built around a programmable FPGA device for onboard data analysis and on-the-fly modification of system detection/operating parameters, and capable of collecting and processing data in very small time bins (<1 millisecond) when used in histogramming mode, or in list mode as a list mode MCA.

  2. Stabilization of Ballooning Modes by Nonparaxial Cells

    SciTech Connect

    Arsenin, V.V.; Zvonkov, A.V.; Skovoroda, A.A.

    2005-01-15

    An analysis is made of the effect of high-curvature stabilizing nonparaxial elements (cells) on the MHD plasma stability in open confinement systems and in confinement systems with closed magnetic field lines. It is shown that the population of particles trapped in such cells has a stabilizing effect not only on convective (flute) modes but also on ballooning modes, which govern the maximum possible {beta} value. In the kinetic approach, which distinguishes between the effects of trapped and passing particles, the maximum possible {beta} values consistent with stability can be much higher than those predicted by the MHD model.

  3. Method for direct detection of pitch angle scattering of energetic electrons caused by whistler mode chorus emissions

    NASA Astrophysics Data System (ADS)

    Kitahara, M.; Katoh, Y.

    2016-06-01

    The Wave-Particle Interaction Analyzer (WPIA), a new instrument proposed by Fukuhara et al. (2009), measures the relative phase angle between the wave magnetic field vector and the velocity vector of each particle and calculates the energy exchange from waves to particles. In this study, we expand its applicability by proposing a method of using the WPIA to directly detect pitch angle scattering of resonant particles by plasma waves by calculating the g values. The g value is defined as the accumulation value of the Lorentz force acting on each particle and indicates the lost momentum of waves. We apply the proposed method to the results of a one-dimensional electron hybrid simulation reproducing the generation of whistler mode chorus emissions around the magnetic equator. Using the wave and particle data obtained at fixed observation points assumed in the simulation system, we conduct a pseudo-observation of the simulation result using the WPIA and analyze the g values. Our analysis yielded significant values indicating the strong pitch angle scattering for electrons in the kinetic energy and pitch angle ranges satisfying the cyclotron resonance condition with the reproduced chorus emissions. The results of this study demonstrate that the proposed method enables us to directly and quantitatively identify the location at which pitch angle scattering occurs in the simulation system and that the method can be applied to the results of space-based observations by the forthcoming Exploration of energization and Radiation in Geospace (ERG) satellite.

  4. Alpha Particle

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Term that is sometimes used to describe a helium nucleus, a positively charged particle that consists of two protons and two neutrons, bound together. Alpha particles, which were discovered by Ernest Rutherford (1871-1937) in 1898, are emitted by atomic nuclei that are undergoing alpha radioactivity. During this process, an unstable heavy nucleus spontaneously emits an alpha particle and transmut...

  5. Particle generator

    DOEpatents

    Hess, Wayne P.; Joly, Alan G.; Gerrity, Daniel P.; Beck, Kenneth M.; Sushko, Peter V.; Shlyuger, Alexander L.

    2005-06-28

    Energy tunable solid state sources of neutral particles are described. In a disclosed embodiment, a halogen particle source includes a solid halide sample, a photon source positioned to deliver photons to a surface of the halide, and a collimating means positioned to accept a spatially defined plume of hyperthermal halogen particles emitted from the sample surface.

  6. Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

    NASA Astrophysics Data System (ADS)

    Salma, I.; Borsós, T.; Weidinger, T.; Aalto, P.; Hussein, T.; Dal Maso, M.; Kulmala, M.

    2011-02-01

    Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6-1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8 × 103 to 29 ×103 cm-3 with a yearly median of 11.8 × 103 cm-3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79 ± 6)%. Typical diurnal variation of the particle number concentration was related to the major emission patterns in cities, new particle formation, sinks of particles and meteorology. Shapes of the monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. New particle formation and growth unambiguously occurred on 83 days, which represent 27% of all relevant days. Hence, new particle formation and growth are not rare phenomena in Budapest. Their frequency showed an apparent seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. New particle formation events were linked to increased gas-phase H2SO4 concentrations. In the studied area, new particle formation is mainly affected by condensation sink and solar radiation. The formation process seems to be not sensitive to SO2, which was present in a yearly median concentration of 6.7 μg m-3. This suggests that the precursor gas was always available in excess. Formation rate of particles with a diameter of 6 nm varied between 1.65 and 12.5 cm-3 s-1 with a mean and standard deviation of (4.2

  7. Drug accumulation by means of noninvasive magnetic drug delivery system

    NASA Astrophysics Data System (ADS)

    Chuzawa, M.; Mishima, F.; Akiyama, Y.; Nishijima, S.

    2011-11-01

    The medication is one of the most general treatment methods, but drugs diffuse in the normal tissues other than the target part by the blood circulation. Therefore, side effect in the medication, particularly for a drug with strong effect such as anti-cancer drug, are a serious issue. Drug Delivery System (DDS) which accumulates the drug locally in the human body is one of the techniques to solve the side-effects. Magnetic Drug Delivery System (MDDS) is one of the active DDSs, which uses the magnetic force. The objective of this study is to accumulate the ferromagnetic drugs noninvasively in the deep part of the body by using MDDS. It is necessary to generate high magnetic field and magnetic gradient at the target part to reduce the side-effects to the tissues with no diseases. The biomimetic model was composed, which consists of multiple model organs connected with diverged blood vessel model. The arrangement of magnetic field was examined to accumulate ferromagnetic drug particles in the target model organ by using a superconducting bulk magnet which can generate high magnetic fields. The arrangement of magnet was designed to generate high and stable magnetic field at the target model organ. The accumulation experiment of ferromagnetic particles has been conducted. In this study, rotating HTS bulk magnet around the axis of blood vessels by centering on the target part was suggested, and the model experiment for magnet rotation was conducted. As a result, the accumulation of the ferromagnetic particles to the target model organ in the deep part was confirmed.

  8. 46 CFR 58.30-25 - Accumulators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... RELATED SYSTEMS Fluid Power and Control Systems § 58.30-25 Accumulators. (a) An accumulator is an unfired... fluid. Accumulators must meet the applicable requirements in § 54.01-5 (c)(3), (c)(4), and (d) of this chapter or the remaining requirements in part 54. (b) If the accumulator is of the gas and fluid...

  9. 46 CFR 58.30-25 - Accumulators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... RELATED SYSTEMS Fluid Power and Control Systems § 58.30-25 Accumulators. (a) An accumulator is an unfired... fluid. Accumulators must meet the applicable requirements in § 54.01-5 (c)(3), (c)(4), and (d) of this chapter or the remaining requirements in part 54. (b) If the accumulator is of the gas and fluid...

  10. 46 CFR 58.30-25 - Accumulators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... RELATED SYSTEMS Fluid Power and Control Systems § 58.30-25 Accumulators. (a) An accumulator is an unfired... fluid. Accumulators must meet the applicable requirements in § 54.01-5 (c)(3), (c)(4), and (d) of this chapter or the remaining requirements in part 54. (b) If the accumulator is of the gas and fluid...

  11. 46 CFR 58.30-25 - Accumulators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... RELATED SYSTEMS Fluid Power and Control Systems § 58.30-25 Accumulators. (a) An accumulator is an unfired... fluid. Accumulators must meet the applicable requirements in § 54.01-5 (c)(3), (c)(4), and (d) of this chapter or the remaining requirements in part 54. (b) If the accumulator is of the gas and fluid...

  12. Preparation of topological modes by Lyapunov control

    PubMed Central

    Shi, Z. C.; Zhao, X. L.; Yi, X. X.

    2015-01-01

    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. PMID:26346317

  13. Preparation of topological modes by Lyapunov control

    NASA Astrophysics Data System (ADS)

    Shi, Z. C.; Zhao, X. L.; Yi, X. X.

    2015-09-01

    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.

  14. Preparation of topological modes by Lyapunov control.

    PubMed

    Shi, Z C; Zhao, X L; Yi, X X

    2015-01-01

    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. PMID:26346317

  15. Particle Detectors

    NASA Astrophysics Data System (ADS)

    Grupen, Claus; Shwartz, Boris

    2011-09-01

    Preface to the first edition; Preface to the second edition; Introduction; 1. Interactions of particles and radiation with matter; 2. Characteristic properties of detectors; 3. Units of radiation measurements and radiation sources; 4. Accelerators; 5. Main physical phenomena used for particle detection and basic counter types; 6. Historical track detectors; 7. Track detectors; 8. Calorimetry; 9. Particle identification; 10. Neutrino detectors; 11. Momentum measurement and muon detection; 12. Ageing and radiation effects; 13. Example of a general-purpose detector: Belle; 14. Electronics; 15. Data analysis; 16. Applications of particle detectors outside particle physics; 17. Glossary; 18. Solutions; 19. Resumé; Appendixes; Index.

  16. Mutagenicity of airborne particles.

    PubMed

    Chrisp, C E; Fisher, G L

    1980-09-01

    The physical and chemical properties of airborne particles are important for the interpretation of their potential biologic significance as genotoxic hazards. For polydisperse particle size distributions, the smallest, most respirable particles are generally the most mutagenic. Particulate collection for testing purposes should be designed to reduce artifact formation and allow condensation of mutagenic compounds. Other critical factors such as UV irradiation, wind direction, chemical reactivity, humidity, sample storage, and temperature of combustion are important. Application of chemical extraction methods and subsequent class fractionation techniques influence the observed mutagenic activity. Particles from urban air, coal fly ash, automobile and diesel exhaust, agricultural burning and welding fumes contain primarily direct-acting mutagens. Cigarette smoke condensate, smoke from charred meat and protein pyrolysates, kerosene soot and cigarette smoke condensates contain primarily mutagens which require metabolic activation. Fractionation coupled with mutagenicity testing indicates that the most potent mutagens are found in the acidic fractions of urban air, coal fly ash, and automobile diesel exhaust, whereas mutagens in rice straw smoke and cigarette smoke condensate are found primarily in the basic fractions. The interaction of the many chemical compounds in complex mixtures from airborne particles is likely to be important in determining mutagenic or comutagenic potentials. Because the mode of exposure is generally frequent and prolonged, the presence of tumor-promoting agents in complex mixtures may be a major factor in evaluation of the carcinogenic potential of airborne particles. PMID:7005667

  17. Assessing the Capacity of Plant Species to Accumulate Particulate Matter in Beijing, China

    PubMed Central

    Mo, Li; Ma, Zeyu; Xu, Yansen; Sun, Fengbin; Lun, Xiaoxiu; Liu, Xuhui; Chen, Jungang; Yu, Xinxiao

    2015-01-01

    Air pollution causes serious problems in spring in northern China; therefore, studying the ability of different plants to accumulate particulate matter (PM) at the beginning of the growing season may benefit urban planners in their attempts to control air pollution. This study evaluated deposits of PM on the leaves and in the wax layer of 35 species (11 shrubs, 24 trees) in Beijing, China. Differences in the accumulation of PM were observed between species. Cephalotaxus sinensis, Euonymus japonicus, Broussonetia papyriferar, Koelreuteria paniculata and Quercus variabilis were all efficient in capturing small particles. The plants exhibiting high amounts of total PM accumulation (on leaf surfaces and/or in the wax layer), also showed comparatively high levels of PM accumulation across all particle sizes. A comparison of shrubs and trees did not reveal obvious differences in their ability to accumulate particles based on growth form; a combination of plantings with different growth forms can efficiently reduce airborne PM concentrations near the ground. To test the relationships between leaf traits and PM accumulation, leaf samples of selected species were observed using a scanning electron microscope. Growth forms with greater amounts of pubescence and increased roughness supported PM accumulation; the adaxial leaf surfaces collected more particles than the abaxial surfaces. The results of this study may inform the selection of species for urban green areas where the goal is to capture air pollutants and mitigate the adverse effects of air pollution on human health. PMID:26506104

  18. Collisionless Trapped Electron Mode Turbulence

    NASA Astrophysics Data System (ADS)

    Lang, Jianying; Chen, Yang; Parker, Scott

    2006-10-01

    Collisionless Trapped Electron Mode (CTEM) turbulence is a likely canidate for explaining anomolous transport in tokamak discharges that have a strong density gradient relative to the ion temperature gradient. Here, CTEM turbulence is investigated using the Gyrokinetic δf GEM code. GEM is electromagnetic, includes full drift-kinetic electrons, generaly axisymmetric equilbria, collisions and minority species. Here, the flux-tube limit is taken and β is so small that the simulations are essentially electrostatic. Linear theory predicts that the instability occurs at √2ɛRLn>1, which agrees very well with the simulation results. With increasing density gradient, it is observed that the most unstable mode transitions from a CTEM to drift wave mode and the short-wavelength modes are most unstable ( 2 > kρi> 1). Nonlinear simulations are underway to address the parametric dependence of particle and energy transport. The importance of zonal flows for CTEM turbulence, is still not well understood and is under investigation. D. R. Ernst et. al., Phys. Plasma 11 (2004) 2637 T. Dannert and F. Jenko, Phys. Plasma 12 (2005) 072309 R. Gatto et. al., Phys. Plasma 13 (2006) 022306 Y. Chen and S. E. Parker, J. Comput. Phys. 189 (2003) 463 Y. Chen ad S.E. Parker, accepted, to appear in J. Comput. Phys. (2006) J. Wesson (1997) Tokamaks, Oxford Science

  19. Spherical harmonic modes of 5.5 post-Newtonian gravitational wave polarizations and associated factorized resummed waveforms for a particle in circular orbit around a Schwarzschild black hole

    SciTech Connect

    Fujita, Ryuichi; Iyer, Bala R.

    2010-08-15

    Recent breakthroughs in numerical relativity enable one to examine the validity of the post-Newtonian expansion in the late stages of inspiral. For the comparison between post-Newtonian (PN) expansion and numerical simulations, the waveforms in terms of the spin-weighted spherical harmonics are more useful than the plus and cross polarizations, which are used for data analysis of gravitational waves. Factorized resummed waveforms achieve better agreement with numerical results than the conventional Taylor expanded post-Newtonian waveforms. In this paper, we revisit the post-Newtonian expansion of gravitational waves for a test particle of mass {mu} in circular orbit of radius r{sub 0} around a Schwarzschild black hole of mass M and derive the spherical harmonic components associated with the gravitational wave polarizations up to order v{sup 11} beyond Newtonian. Using the more accurate h{sub lm}'s computed in this work, we provide the more complete set of associated {rho}{sub lm}'s and {delta}{sub lm}'s that form important bricks in the factorized resummation of waveforms with potential applications for the construction of further improved waveforms for prototypical compact binary sources in the future. We also provide ready-to-use expressions of the 5.5PN gravitational waves polarizations h{sub +} and h{sub x} in the test-particle limit for gravitational waves data analysis applications. Additionally, we provide closed analytical expressions for 2.5PN h{sub lm}, 2PN {rho}{sub lm}, and 3PN {delta}{sub lm}, for general multipolar orders l and m in the test-particle limit. Finally, we also examine the implications of the present analysis for compact binary sources in Laser Interferometer Space Antenna.

  20. Estuarine fine-particle budget determined from radionuclide tracers

    SciTech Connect

    Olsen, C.R.; Cutshall, N.H.; Larsen, I.L.; Simpson, H.J.; Trier, R.M.; Bopp, R.F.

    1985-01-01

    The sedimentary distributions of radiocesium and plutonium have been used to determine patterns of fine-particle accumulation, estimate net sediment fluxes from different sources, and develop a fine-particle budget for the Hudson-Raritan estuary. It is proposed that the rates and patterns of fine-particle accumulation reflect a sediment surface in dynamic equilibrium with the wave and current regimes. Rates of accumulation in most estuarine areas appear to equal the rate of sea-level rise or land subsidence. Localized areas, which have not yet attained or are presently out of equilibrium, serve as fine particle traps. 13 references, 1 table.

  1. Metal accumulating plants: Medium's role

    NASA Astrophysics Data System (ADS)

    Rabier, J.; Prudent, P.; Szymanska, B.; Mevy, J.-P.

    2003-05-01

    To evaluate phytoremediation potentialities by metal accumulation in tolerant plants, trials are carried out using in vitro cultures. Organie compounds influence on metal accumulation is studied with metals supplemented media. The tested compounds on zinc and lead absorption by Brassica juncea, are chelating agents (EDTA, citric acid) and soluble organic fractions of compost. EDTA seems to enhance the transfer of lead in plant but it is the opposite in the case of zinc. Citric acid stimulates root absorption for both zinc and lead. For the aqueous extracts of compost, variable effects are obtained according to the origin of compost (green wastes and food wastes). In'all tested conditions of cultures, zinc is mainly exported towards shoot while lead is stored in root.

  2. Special purpose modes in photonic band gap fibers

    SciTech Connect

    Spencer, James; Noble, Robert; Campbell, Sara

    2013-04-02

    Photonic band gap fibers are described having one or more defects suitable for the acceleration of electrons or other charged particles. Methods and devices are described for exciting special purpose modes in the defects including laser coupling schemes as well as various fiber designs and components for facilitating excitation of desired modes. Results are also presented showing effects on modes due to modes in other defects within the fiber and due to the proximity of defects to the fiber edge. Techniques and devices are described for controlling electrons within the defect(s). Various applications for electrons or other energetic charged particles produced by such photonic band gap fibers are also described.

  3. Accumulation of cadmium from the dissolved and particulate phases by the freshwater mussel, Elliptio complanata

    SciTech Connect

    Yankovich, T.

    1995-12-31

    The primary objective of the current study was to quantify cadmium accumulation by Elliptio complanata from suspended particulates relative to the dissolved phase. Results obtained from this study suggest that particle physico-chemical properties and their associated cadmium concentrations may play a role in cadmium bioaccumulation by E. complanata. This accumulation of cadmium is due to direct uptake from the particulate phase and/or accumulation of dissolved cadmium which has leached off particles. The importance of the particulate phase in cadmium uptake is related to the type of particle to which mussels are exposed. No significant cadmium bioaccumulation was observed when mussels consumed Cd-contaminated kaolinite or illite clay particles. Significant uptake was observed by mussels exposed to Cd-contaminated montmorillonite clay particles at high bound cadmium levels; however, the dissolved phase accounted for all observed Cd accumulation, suggesting that equilibrium partitioning into the aqueous phase represented the key route of cadmium uptake from clay particles. Cadmium uptake did not occur when mussels were exposed to natural sediment particles containing low organic carbon concentrations, but significant bioaccumulation was observed when mussels consumed Cd-contaminated sediments with relatively high organic carbon contents. Dissolved cadmium concentrations present in sediment suspensions with low and high organic carbon contents were similar, suggesting that the particulate phase was the source of cadmium uptake. These results indicate that particle processing and selective feeding behaviors by filter-feeding bivalves may play a key role in determining the relative importance of dissolved and particulate phases in cadmium bioaccumulation.

  4. An optical particle size spectrometer for aircraft-borne measurements in IAGOS-CARIBIC

    NASA Astrophysics Data System (ADS)

    Hermann, M.; Weigelt, A.; Assmann, D.; Pfeifer, S.; Müller, T.; Conrath, T.; Voigtländer, J.; Heintzenberg, J.; Wiedensohler, A.; Martinsson, B. G.; Deshler, T.; Brenninkmeijer, C. A. M.; Zahn, A.

    2015-11-01

    The particle number size distribution is an important parameter to characterize the atmospheric aerosol and its influence on the Earth's climate. Here we describe a new Optical Particle Size Spectrometer (OPSS) for measurements of the accumulation mode particle number size distribution in the tropopause region onboard a passenger aircraft (IAGOS-CARIBIC observatory (In-service Aircraft for a Global Observing System - Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container)). A modified "KS93 particle sensor" from RION Co., Ltd. together with a new airflow system and a dedicated data acquisition system are the key components of the CARIBIC OPSS. The instrument records individual particle pulses in the particle size range 130-1110 nm diameter (for a particle refractive index of 1.47-i0.006 for an upper tropospheric (UT) aerosol particle) and thus allows the post-flight choice of the time resolution and the size distribution bin width. The CARIBIC OPSS has a 50 % particle detection diameter of 152 nm and a maximum asymptotic counting efficiency of 98 %. The instruments measurement performance shows no pressure dependency and no coincidence for free tropospheric conditions. The size response function of the CARIBIC OPSS was obtained by a polystyrene latex calibration in combination with model calculations. Particle number size distributions measured with the new OPSS in the lowermost stratosphere agreed within a factor of two in concentration with balloon-borne measurements over western North America. Since June 2010 the CARIBIC OPSS is deployed once per month in the IAGOS-CARIBIC observatory.

  5. An optical particle size spectrometer for aircraft-borne measurements in IAGOS-CARIBIC

    NASA Astrophysics Data System (ADS)

    Hermann, Markus; Weigelt, Andreas; Assmann, Denise; Pfeifer, Sascha; Muller, Thomas; Conrath, Thomas; Voigtlander, Jens; Heintzenberg, Jost; Wiedensohler, Alfred; Martinsson, Bengt G.; Deshler, Terry; Brenninkmeijer, Carl A. M.; Zahn, Andreas

    2016-05-01

    The particle number size distribution is an important parameter to characterize the atmospheric aerosol and its influence on the Earth's climate. Here we describe a new optical particle size spectrometer (OPSS) for measurements of the accumulation mode particle number size distribution in the tropopause region on board a passenger aircraft (IAGOS-CARIBIC observatory: In-service Aircraft for a Global Observing System - Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container). A modified KS93 particle sensor from RION Co., Ltd., together with a new airflow system and a dedicated data acquisition system, is the key component of the CARIBIC OPSS. The instrument records individual particle pulse signal curves in the particle size range 130-1110 nm diameter (for a particle refractive index of 1.47-i0.006) together with a time stamp and thus allows the post-flight choice of the time resolution and the size distribution bin width. The CARIBIC OPSS has a 50 % particle detection diameter of 152 nm and a maximum asymptotic counting efficiency of 98 %. The instrument's measurement performance shows no pressure dependency and no particle coincidence for free tropospheric conditions. The size response function of the CARIBIC OPSS was obtained by a polystyrene latex calibration in combination with model calculations. Particle number size distributions measured with the new OPSS in the lowermost stratosphere agreed within a factor of 2 in concentration with balloon-borne measurements over western North America. Since June 2010 the CARIBIC OPSS is deployed once per month in the IAGOS-CARIBIC observatory.

  6. Mechanisms of intrahepatic triglyceride accumulation

    PubMed Central

    Ress, Claudia; Kaser, Susanne

    2016-01-01

    Hepatic steatosis defined as lipid accumulation in hepatocytes is very frequently found in adults and obese adolescents in the Western World. Etiologically, obesity and associated insulin resistance or excess alcohol intake are the most frequent causes of hepatic steatosis. However, steatosis also often occurs with chronic hepatitis C virus (HCV) infection and is also found in rare but potentially life-threatening liver diseases of pregnancy. Clinical significance and outcome of hepatic triglyceride accumulation are highly dependent on etiology and histological pattern of steatosis. This review summarizes current concepts of pathophysiology of common causes of hepatic steatosis, including non-alcoholic fatty liver disease (NAFLD), alcoholic fatty liver disease, chronic HCV infections, drug-induced forms of hepatic steatosis, and acute fatty liver of pregnancy. Regarding the pathophysiology of NAFLD, this work focuses on the close correlation between insulin resistance and hepatic triglyceride accumulation, highlighting the potential harmful effects of systemic insulin resistance on hepatic metabolism of fatty acids on the one side and the role of lipid intermediates on insulin signalling on the other side. Current studies on lipid droplet morphogenesis have identified novel candidate proteins and enzymes in NAFLD. PMID:26819531

  7. Microspectroscopic Analysis of Anthropogenic- and Biogenic-Influenced Aerosol Particles during the SOAS Field Campaign

    NASA Astrophysics Data System (ADS)

    Ault, A. P.; Bondy, A. L.; Nhliziyo, M. V.; Bertman, S. B.; Pratt, K.; Shepson, P. B.

    2013-12-01

    During the summer, the southeastern United States experiences a cooling haze due to the interaction of anthropogenic and biogenic aerosol sources. An objective of the summer 2013 Southern Oxidant and Aerosol Study (SOAS) was to improve our understanding of how trace gases and aerosols are contributing to this relative cooling through light scattering and absorption. To improve understanding of biogenic-anthropogenic interactions through secondary organic aerosol (SOA) formation on primary aerosol cores requires detailed physicochemical characterization of the particles after uptake and processing. Our measurements focus on single particle analysis of aerosols in the accumulation mode (300-1000 nm) collected using a multi orifice uniform deposition impactor (MOUDI) at the Centreville, Alabama SEARCH site. Particles were characterized using an array of microscopic and spectroscopic techniques, including: scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), and Raman microspectroscopy. These analyses provide detailed information on particle size, morphology, elemental composition, and functional groups. This information is combined with mapping capabilities to explore individual particle spatial patterns and how that impacts structural characteristics. The improved understanding will be used to explore how sources and processing (such as SOA coating of soot) change particle structure (i.e. core shell) and how the altered optical properties impact air quality/climate effects on a regional scale.

  8. Normal modes and continuous spectra

    SciTech Connect

    Balmforth, N.J.; Morrison, P.J.

    1994-12-01

    The authors consider stability problems arising in fluids, plasmas and stellar systems that contain singularities resulting from wave-mean flow or wave-particle resonances. Such resonances lead to singularities in the differential equations determining the normal modes at the so-called critical points or layers. The locations of the singularities are determined by the eigenvalue of the problem, and as a result, the spectrum of eigenvalues forms a continuum. They outline a method to construct the singular eigenfunctions comprising the continuum for a variety of problems.

  9. Morphology and Optical Properties of Mixed Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Fard, Mehrnoush M.; Krieger, Ulrich; Rudich, Yinon; Marcolli, Claudia; Peter, Thomas

    2015-04-01

    Experiments and modeling studies have shown that deliquesced aerosols can be present not only as one-phase system containing organics, inorganic salts and water, but often as two-phase systems consisting of a predominantly organic and a predominantly inorganic aqueous phase 1,2. Recent laboratory studies conducted with model mixtures representing tropospheric aerosols1,2,3, secondary organic aerosol (SOA) from smog chamber experiments4, and field measurements5 suggest that liquid- liquid phase separations (LLPS) is indeed a common phenomenon in mixed organic/ ammonium sulfate (AS) particles. During LLPS, particles may adopt different morphologies mainly core- shell and partially engulfed. A core- shell configuration will have consequences for heterogeneous chemistry and hygroscopicity and as a result will alter the optical properties of the particles since the aqueous inorganic-rich phase will be totally enclosed by a probably highly viscous organic coating with low diffusivity for reactants and water. The primary objective of this project is to establish a method for investigating the morphology of mixed inorganic and absorbing organic compounds of atmospheric relevance and study their radiative properties before, during, and after phase transitions mainly during LLPS. This will be the first study looking into the radiative effect of LLPS in detail. In this first experiment, the behavior of single droplets of carminic acid (CA)/ AS/ H2O mixture was monitored during relative humidity (RH) cycles using optical microscopy. The same mixture particle was levitated in an electrodynamic balance (EDB) and the change in its absorption properties was measured at varying RH. We also intend to determine the occurrence of LLPS in accumulation- sized particles and the change in their absorption using a cavity ring down aerosol spectrometer. If LLPS alters the absorptive properties of the suggested model aerosols significantly, absorption measurements of accumulation mode

  10. Quantum limited particle sensing in optical tweezers

    SciTech Connect

    Tay, J.W.; Hsu, Magnus T. L.; Bowen, Warwick P.

    2009-12-15

    Particle sensing in optical tweezers systems provides information on the position, velocity, and force of the specimen particles. The conventional quadrant detection scheme is applied ubiquitously in optical tweezers experiments to quantify these parameters. In this paper, we show that quadrant detection is nonoptimal for particle sensing in optical tweezers and propose an alternative optimal particle sensing scheme based on spatial homodyne detection. A formalism for particle sensing in terms of transverse spatial modes is developed and numerical simulations of the efficacies of both quadrant and spatial homodyne detection are shown. We demonstrate that 1 order of magnitude improvement in particle sensing sensitivity can be achieved using spatial homodyne over quadrant detection.

  11. Particle astrophysics

    NASA Astrophysics Data System (ADS)

    Sadoulet, Bernard; Cronin, James; Aprile, Elena; Barish, Barry C.; Beier, Eugene W.; Brandenberger, Robert; Cabrera, Blas; Caldwell, David; Cassiday, George; Cline, David B.

    The following scientific areas are reviewed: (1) cosmology and particle physics (particle physics and the early universe, dark matter, and other relics); (2) stellar physics and particles (solar neutrinos, supernovae, and unconventional particle physics); (3) high energy gamma ray and neutrino astronomy; (4) cosmic rays (space and ground observations). Highest scientific priorities for the next decade include implementation of the current program, new initiatives, and longer-term programs. Essential technological developments, such as cryogenic detectors of particles, new solar neutrino techniques, and new extensive air shower detectors, are discussed. Also a certain number of institutional issues (the funding of particle astrophysics, recommended funding mechanisms, recommended facilities, international collaborations, and education and technology) which will become critical in the coming decade are presented.

  12. Particle therapy

    SciTech Connect

    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.

  13. Particle astrophysics

    NASA Technical Reports Server (NTRS)

    Sadoulet, Bernard; Cronin, James; Aprile, Elena; Barish, Barry C.; Beier, Eugene W.; Brandenberger, Robert; Cabrera, Blas; Caldwell, David; Cassiday, George; Cline, David B.

    1991-01-01

    The following scientific areas are reviewed: (1) cosmology and particle physics (particle physics and the early universe, dark matter, and other relics); (2) stellar physics and particles (solar neutrinos, supernovae, and unconventional particle physics); (3) high energy gamma ray and neutrino astronomy; (4) cosmic rays (space and ground observations). Highest scientific priorities for the next decade include implementation of the current program, new initiatives, and longer-term programs. Essential technological developments, such as cryogenic detectors of particles, new solar neutrino techniques, and new extensive air shower detectors, are discussed. Also a certain number of institutional issues (the funding of particle astrophysics, recommended funding mechanisms, recommended facilities, international collaborations, and education and technology) which will become critical in the coming decade are presented.

  14. Size evolution of ultrafine particles: Differential signatures of normal and episodic events.

    PubMed

    Joshi, Manish; Khan, Arshad; Anand, S; Sapra, B K

    2016-01-01

    The effect of fireworks on the aerosol number characteristics of atmosphere was studied for an urban mega city. Measurements were made at 50 m height to assess the local changes around the festival days. Apart from the increase in total number concentration and characteristic accumulation mode, short-term increase of ultrafine particle concentration was noted. Total number concentration varies an order of magnitude during the measurement period in which peak occurs at a frequency of approximately one per day. On integral scale, it seems not possible to distinguish an episodic (e.g. firework bursting induced aerosol emission) and a normal (ambient atmospheric changes) event. However these events could be differentiated on the basis of size evolution analysis around number concentration peaks. The results are discussed relative to past studies and inferences are drawn towards aerosol signatures of firework bursting. The short-term burst in ultrafine particle concentration can pose an inhalation hazard. PMID:26552523

  15. Morphology and Optical Properties of Mixed Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Fard, Mehrnoush M.; Krieger, Ulrich; Rudich, Yinon; Marcolli, Claudia; Peter, Thomas

    2016-04-01

    LLPS in accumulation-sized particles and the change in their absorption using a cavity ring down aerosol spectrometer. If LLPS alters the absorptive properties of the suggested model aerosols significantly, absorption measurements of accumulation mode particles of the same composition would allow proving that LLPS indeed occurs in particles of accumulation mode size. Up to now LLPS has not been studied for particles in this size range. References: 1. Bertram, et al. Atmos. Chem & Phys, 11(21), 10995-11006, 2011.
 2. Krieger, et al. Chemical Society Reviews, 41(19), 6631-6662, 2012 
3. Song, M. et al. Geophys Res Lett, 39(19), 2012b 4. Smith et al. Atmos Chem & Phys, 12(20), 9613- 9628, 2012.
 5. You, Y. et al. Proceedings of the National Academy of Sciences, 109(33), 13188-13193, 2012.

  16. Aerosol size distribution and new particle formation in the western Yangtze River Delta of China: 2 years of measurements at the SORPES station

    NASA Astrophysics Data System (ADS)

    Qi, X. M.; Ding, A. J.; Nie, W.; Petäjä, T.; Kerminen, V.-M.; Herrmann, E.; Xie, Y. N.; Zheng, L. F.; Manninen, H.; Aalto, P.; Sun, J. N.; Xu, Z. N.; Chi, X. G.; Huang, X.; Boy, M.; Virkkula, A.; Yang, X.-Q.; Fu, C. B.; Kulmala, M.

    2015-11-01

    Aerosol particles play important roles in regional air quality and global climate change. In this study, we analyzed 2 years (2011-2013) of measurements of submicron particles (6-800 nm) at a suburban site in the western Yangtze River Delta (YRD) of eastern China. The number concentrations (NCs) of particles in the nucleation, Aitken and accumulation modes were 5300 ± 5500, 8000 ± 4400, 5800 ± 3200 cm-3, respectively. The NCs of total particles are comparable to those at urban/suburban sites in other Chinese megacities, such as Beijing, but about 10 times higher than in the remote western China. Long-range and regional transport largely influenced number concentrations and size distributions of submicron particles. The highest and lowest accumulation-mode particle number concentrations were observed in air masses from the YRD and coastal regions, respectively. Continental air masses from inland brought the highest concentrations of nucleation-mode particles. New particle formation (NPF) events, apparent in 44 % of the effective measurement days, occurred frequently in all the seasons except winter. The frequency of NPF in spring, summer and autumn is much higher than other measurement sites in China. Sulfuric acid was found to be the main driver of NPF events. The particle formation rate was the highest in spring (3.6 ± 2.4 cm-3 s-1), whereas the particle growth rate had the highest values in summer (12.8 ± 4.4 nm h-1). The formation rate was typically high in relatively clean air masses, whereas the growth rate tended to be high in the polluted YRD air masses. The frequency of NPF events and the particle growth rates showed a strong year-to-year difference. In the summer of 2013, associated with a multi-week heat wave and strong photochemical processes, NPF events occurred with larger frequency and higher growth rates compared with the same period in 2012. The difference in the location and strength of the subtropical high pressure system, which influences

  17. A New Dynamic Accumulator for Batch Updates

    NASA Astrophysics Data System (ADS)

    Wang, Peishun; Wang, Huaxiong; Pieprzyk, Josef

    A dynamic accumulator is an algorithm, which gathers together a large set of elements into a constant-size value such that for a given element accumulated, there is a witness confirming that the element was indeed included into the value, with a property that accumulated elements can be dynamically added and deleted into/from the original set such that the cost of an addition or deletion operation is independent of the number of accumulated elements. Although the first accumulator was presented ten years ago, there is still no standard formal definition of accumulators. In this paper, we generalize formal definitions for accumulators, formulate a security game for dynamic accumulators so-called Chosen Element Attack (CEA), and propose a new dynamic accumulator for batch updates based on the Paillier cryptosystem. Our construction makes a batch of update operations at unit cost. We prove its security under the extended strong RSA (es-RSA) assumption.

  18. Large mode radius resonators

    NASA Technical Reports Server (NTRS)

    Harris, Michael R.

    1987-01-01

    Resonator configurations permitting operation with large mode radius while maintaining good transverse mode discrimination are considered. Stable resonators incorporating an intracavity telescope and unstable resonator geometries utilizing an output coupler with a Gaussian reflectivity profile are shown to enable large radius single mode laser operation. Results of heterodyne studies of pulsed CO2 lasers with large (11mm e sup-2 radius) fundamental mode sizes are presented demonstrating minimal frequency sweeping in accordance with the theory of laser-induced medium perturbations.

  19. Patterned flattened modes.

    PubMed

    Messerly, Michael J; Pax, Paul H; Dawson, Jay W

    2013-09-01

    We show that field-flattened strands may be added to and arbitrarily positioned within a field-flattened shell to create patterned, flattened modes. Patterning does not alter the effective index or flatness of the flattened mode but does alter the characteristics of other modes; we show that it can improve a flattened mode's bend performance significantly. Patterning provides a new and potentially valuable waveguide design tool that may lead to higher-power transport and laser fibers. PMID:23988948

  20. Magnetic particles

    NASA Technical Reports Server (NTRS)

    Chang, Manchium (Inventor); Colvin, Michael S. (Inventor)

    1989-01-01

    Magnetic polymer particles are formed by swelling porous, polymer particles and impregnating the particles with an aqueous solution of precursor magnetic metal salt such as an equimolar mixture of ferrous chloride and ferric chloride. On addition of a basic reagent such as dilute sodium hydroxide, the metal salts are converted to crystals of magnetite which are uniformly contained througout the pores of the polymer particle. The magnetite content can be increased and neutral buoyancy achieved by repetition of the impregnaton and neutralization steps to adjust the magnetite content to a desired level.

  1. Integrated mode converter for mode division multiplexing

    NASA Astrophysics Data System (ADS)

    Perez-Galacho, Diego; Alonso-Ramos, Carlos Alberto; Marris-Morini, Delphine; Vakarin, Vladyslav; Le Roux, Xavier; Ortega-Moñux, Alejandro; Wangüemert-Perez, Juan Gonzalo; Vivien, Laurent

    2016-05-01

    The ever growing demands of bandwidth in optical communication systems are making traditional Wavelength Division Multiplexing (WDM) based systems to reach its limit. In order to cope with future bandwidth demand is necessary to use new levels of orthogonality, such as the waveguide mode or the polarization state. Mode Division Multiplexing (MDM) has recently attracted attention as a possible solution to increase aggregate bandwidth. In this work we discuss the proposition a of mode converter that can cover the whole C-Band of optical communications. The Mode Converter is based on two Multimode Interference (MMI) couplers and a phase shifter. Insertion loss (IL) below 0.2 dB and Extinction ratio (ER) higher than 20 dB in a broad bandwidth range of 1.5 μm to 1.6 μm have been estimated. The total length of the device is less than 30 μm.

  2. Edge-localized-modes in tokamaks

    SciTech Connect

    Leonard, A. W.

    2014-09-15

    Edge-localized-modes (ELMs) are a ubiquitous feature of H-mode in tokamaks. When gradients in the H-mode transport barrier grow to exceed the MHD stability limit the ELM instability grows explosively, rapidly transporting energy and particles onto open field lines and material surfaces. Though ELMs provide additional particle and impurity transport through the H-mode transport barrier, enabling steady operation, the resulting heat flux transients to plasma facing surfaces project to large amplitude in future low collisionality burning plasma tokamaks. Measurements of the ELM heat flux deposition onto material surfaces in the divertor and main chamber indicate significant broadening compared to inter-ELM heat flux, with a timescale for energy deposition that is consistent with sonic ion flow and numerical simulation. Comprehensive ELM simulation is highlighting the important physics processes of ELM transport including parallel transport due to magnetic reconnection and turbulence resulting from collapse of the H-mode transport barrier. Encouraging prospects for ELM control and/or suppression in future tokamaks include intrinsic modes of ELM free operation, ELM triggering with frequent small pellet injection and the application of 3D magnetic fields.

  3. Accumulation and Inactivation of Avian Influenza Virus by the Filter-Feeding Invertebrate Daphnia magna

    PubMed Central

    Borchardt, Mark A.; Spencer, Susan K.

    2013-01-01

    The principal mode of avian influenza A virus (AIV) transmission among wild birds is thought to occur via an indirect fecal-oral route, whereby individuals are exposed to virus from the environment through contact with virus-contaminated water. AIV can remain viable for an extended time in water; however, little is known regarding the influence of the biotic community (i.e., aquatic invertebrates) on virus persistence and infectivity in aquatic environments. We conducted laboratory experiments to investigate the ability of an aquatic filter-feeding invertebrate, Daphnia magna, to accumulate virus from AIV-dosed water under the hypothesis that they represent a potential vector of AIV to waterfowl hosts. We placed live daphnids in test tubes dosed with low-pathogenicity AIV (H3N8 subtype isolated from a wild duck) and sampled Daphnia tissue and the surrounding water using reverse transcription-quantitative PCR (RT-qPCR) at 3- to 120-min intervals for up to 960 min following dosing. Concentrations of viral RNA averaged 3 times higher in Daphnia tissue than the surrounding water shortly after viral exposure, but concentrations decreased exponentially through time for both. Extracts from Daphnia tissue were negative for AIV by cell culture, whereas AIV remained viable in water without Daphnia present. Our results suggest daphnids can accumulate AIV RNA and effectively remove virus particles from water. Although concentrations of viral RNA were consistently higher in Daphnia tissue than the water, additional research is needed on the time scale of AIV inactivation after Daphnia ingestion to fully elucidate Daphnia's role as a potential vector of AIV infection to aquatic birds. PMID:24038705

  4. The Nature of Accelerating Modes in PBG Fibers

    SciTech Connect

    Noble, TRobert J.; /SLAC

    2011-05-19

    Transverse magnetic (TM) modes with phase velocities at or just below the speed of light, c, are intended to accelerate relativistic particles in hollow-core, photonic band gap (PBG) fibers. These are so-called 'surface defect modes', being lattice modes perturbed by the defect to have their frequencies shifted into the band gap, and they can have any phase velocity. PBG fibers also support so-called 'core defect modes' which are characterized as having phase velocities always greater than c and never cross the light line. In this paper we explore the nature of these two classes of accelerating modes and compare their properties.

  5. Measurement of intravenously administered γ-Fe2O3 particle amount in mice tissues using vibrating sample magnetometer.

    PubMed

    Kishimoto, Mikio; Miyamoto, Ryoichi; Oda, Tatsuya; Ohara, Yusuke; Yanagihara, Hideto; Ohkohchi, Nobuhiro; Kita, Eiji

    2014-12-01

    Dispersions of platelet γ-Fe2O3 particles 30-50nm in size were intravenously administered to mice and the amount of particles accumulated in each tissue was obtained by magnetization measurement using a vibrating sample magnetometer. Background noise was greatly reduced by measuring dried tissues under a magnetic field of 500 Oe so that the effect of diamagnetism was slight. Remarkable particle accumulation was observed in the liver and spleen. Considerable particle accumulation was observed in the lung when a large quantity of γ-Fe2 O3 particles was administered. There was no significant particle accumulation in the kidney and heart. PMID:25122839

  6. Polycyclic aromatic hydrocarbons in urban atmosphere of Guangzhou, China: Size distribution characteristics and size-resolved gas-particle partitioning

    NASA Astrophysics Data System (ADS)

    Yu, Huan; Yu, Jian Zhen

    2012-07-01

    Size distributions of thirteen polycyclic aromatic hydrocarbons (PAHs), elemental carbon (EC), and organic carbon (OC) in the range of 0.01-18 μm were measured using a nano Micro-Orifice Uniform Deposit Impactor (nano-MOUDI) in an urban location in Guangzhou, China in July 2006. PAH size distributions were fit with five modes and the respective mass median aerodynamic diameters (MMAD) are: Aitken mode (MMAD: ˜0.05 μm), three accumulation modes AMI, AMII, AMIII (MMAD: 0.13-0.17 μm, 0.4-0.45 μm, and 0.9-1.2 μm, respectively), and coarse mode (MMAD: 4-6 μm). Seven-ring PAH was mainly in AMII and AMIII. Five- and six-ring PAHs were found to be abundant in all the three AM. Three- and four-ring PAHs had a significant presence in the coarse mode in addition to the three AM. Size-resolved gas-particle partition coefficients of PAHs (Kp) were estimated using measured EC and OC data. The Kp values of a given PAH could differ by a factor of up to ˜7 on particles in different size modes, with the highest Kp associated with the AMI particles and the lowest Kp associated with the coarse mode particles. Comparison of calculated overall Kp with measured Kp values in Guangzhou by Yang et al. (2010) shows that adsorption on EC appeared to be the dominant mechanism driving the gas-particle partitioning of three- and four-ring PAHs while absorption in OM played a dominant role for five- and six-ring PAHs. The calculated equilibrium timescales of repartitioning indicate that five- to seven-ring PAHs could not achieve equilibrium partitioning within their typical residence time in urban atmospheres, while three- and four-ring PAHs could readily reach new equilibrium states in particles of all sizes. A partitioning flux is therefore proposed to replace the equilibrium assumption in modeling PAH transport and fate.

  7. Racial Differences in Patterns of Wealth Accumulation

    ERIC Educational Resources Information Center

    Gittleman, Maury; Wolff, Edward N.

    2004-01-01

    The race differences in patterns of asset accumulations were examined using PSD data for 1984, 1989 and 1994. The results indicate that inheritances led to wealth accumulations among whites as compared to the African Americans.

  8. Neurodegeneration with brain iron accumulation (NBIA)

    MedlinePlus

    ... gov/ency/article/001225.htm Neurodegeneration with brain iron accumulation (NBIA) To use the sharing features on this page, please enable JavaScript. Neurodegeneration with brain iron accumulation (formerly known as Hallervorden-Spatz disease) is ...

  9. Echo particle image velocimetry.

    PubMed

    DeMarchi, Nicholas; White, Christopher

    2012-01-01

    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

  10. Aerosol size distribution and new particle formation in western Yangtze River Delta of China: two-year measurement at the SORPES station

    NASA Astrophysics Data System (ADS)

    Qi, X. M.; Ding, A. J.; Nie, W.; Petäjä, T.; Kerminen, V.-M.; Herrmann, E.; Xie, Y. N.; Zheng, L. F.; Manninen, H.; Aalto, P.; Sun, J. N.; Xu, Z. N.; Chi, X. G.; Huang, X.; Boy, M.; Virkkula, A.; Yang, X.-Q.; Fu, C. B.; Kulmala, M.

    2015-04-01

    Aerosol particles play important roles in regional air quality and global climate change. In this study, we analyzed two-year (2011-2013) of measurements of submicron particles (6-800 nm) at a suburban site in western Yangtze River delta (YRD) of East China. The number concentrations (NCs) of particles in the nucleation, Aitken and accumulation modes were 5300 ± 5500, 8000 ± 4400, 5800 ± 3200 cm-3, respectively. Number concentrations and size distributions of submicron particles were also influenced by long-range and regional transport of air masses. The highest and lowest accumulation mode particle number concentrations were observed in air masses from YRD and coastal region, respectively. Continental air masses from inland had the highest concentrations of nucleation mode particles. New particle formation (NPF) events, apparent in 44% of the effective measurement days, occurred frequently in all the seasons except winter. Radiation and pre-existing particles were found to be the main factors influencing the occurrence of NPF events. The particle formation rate was the highest in spring (3.6 ± 2.4 cm-3 s-1), whereas the particle growth rate had the highest values in summer (12.8 ± 4.4 nm h-1). The formation rate was typically high in relatively clean air masses, whereas the growth rate tended to be high in the polluted YRD air masses. The frequency of NPF events and the growth rate showed a strong year-to-year difference. In the summer of 2013, associated with a multi-week heat wave and photochemical pollution, NPF events occurred more frequently and the growth rate was much higher than in the same period of 2012. The difference in the location and strength of sub-tropical High, which influences the air mass transport pathways and solar radiation, seems to be the driving cause for year-to-year differences. This study reported the longest continuous measurement records of submicron particles in the East China and gained a comprehensive understanding of the

  11. Quantum teleportation with identical particles

    NASA Astrophysics Data System (ADS)

    Marzolino, Ugo; Buchleitner, Andreas

    2015-03-01

    We study teleportation with identical massive particles. Indistinguishability imposes that the relevant degrees of freedom to be teleported are not particles, but rather addressable orthogonal modes. We discuss the performances of teleportation under the constraint of conservation of the total number of particles. The latter inevitably decreases the teleportation fidelity. Moreover, even though a phase reference, given by the coupling to a reservoir, circumvents the constraint, it does not restore perfect deterministic teleportation. The latter is only achievable with some special resource entangled states and when the number of particles tends to infinity. Interestingly, some of such states are the many-particle atomic coherent states and the ground state of cold atoms loaded into a double well potential, which are routinely prepared in experiments.

  12. Microphysical processing of aerosol particles in orographic clouds

    NASA Astrophysics Data System (ADS)

    Pousse-Nottelmann, S.; Zubler, E. M.; Lohmann, U.

    2015-08-01

    An explicit and detailed treatment of cloud-borne particles allowing for the consideration of aerosol cycling in clouds has been implemented into COSMO-Model, the regional weather forecast and climate model of the Consortium for Small-scale Modeling (COSMO). The effects of aerosol scavenging, cloud microphysical processing and regeneration upon cloud evaporation on the aerosol population and on subsequent cloud formation are investigated. For this, two-dimensional idealized simulations of moist flow over two bell-shaped mountains were carried out varying the treatment of aerosol scavenging and regeneration processes for a warm-phase and a mixed-phase orographic cloud. The results allowed us to identify different aerosol cycling mechanisms. In the simulated non-precipitating warm-phase cloud, aerosol mass is incorporated into cloud droplets by activation scavenging and released back to the atmosphere upon cloud droplet evaporation. In the mixed-phase cloud, a first cycle comprises cloud droplet activation and evaporation via the Wegener-Bergeron-Findeisen (WBF) process. A second cycle includes below-cloud scavenging by precipitating snow particles and snow sublimation and is connected to the first cycle via the riming process which transfers aerosol mass from cloud droplets to snowflakes. In the simulated mixed-phase cloud, only a negligible part of the total aerosol mass is incorporated into ice crystals. Sedimenting snowflakes reaching the surface remove aerosol mass from the atmosphere. The results show that aerosol processing and regeneration lead to a vertical redistribution of aerosol mass and number. Thereby, the processes impact the total aerosol number and mass and additionally alter the shape of the aerosol size distributions by enhancing the internally mixed/soluble Aitken and accumulation mode and generating coarse-mode particles. Concerning subsequent cloud formation at the second mountain, accounting for aerosol processing and regeneration increases

  13. 47 CFR 32.3100 - Accumulated depreciation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Accumulated depreciation. 32.3100 Section 32... Accumulated depreciation. (a) This account shall include the accumulated depreciation associated with the... with depreciation amounts concurrently charged to Account 6561, Depreciation...

  14. 46 CFR 58.30-25 - Accumulators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Accumulators. 58.30-25 Section 58.30-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Fluid Power and Control Systems § 58.30-25 Accumulators. (a) An accumulator is an unfired pressure vessel in which energy is...

  15. Cloud condensation nuclei characteristics of Asian dust particles over the western and central North Pacific

    NASA Astrophysics Data System (ADS)

    Uematsu, M.; Furutani, H.; Kawata, R.; Nakayama, H.

    2015-12-01

    Marine aerosols, such as sea salt particles, and sulfate and organic particles originated from marine biotas, exist in the marine atmosphere. Additionally, continental aerosols, such as dust and anthropogenic substances are transported over the open oceans. Variation of number concentration of cloud condensation nuclei (CCN) depends on the number-size distribution and chemical compositions of aerosols, and affects the lifetime and the reflectivity of clouds over the open oceans. During the R/V Hakuho Maru KH-12-1 cruise from Callao to Tokyo via Honolulu in the Pacific Ocean (23 January - 7 March 2012), aerosol number-size distribution and CCN number concentration were continuously measured, and the marine aerosols for chemical analysis were collected on shipboard. In the marine atmosphere over the Pacific, averaged aerosol total number concentration (TN) was 280 cm-3. Bimodal number-size distributions were observed frequently with peaks at 40-60 nm (Aitken mode) and 160-230 nm (accumulation mode). CCN concentrations were categorized by assuming three types of particles by chemical compositions (i.e., NaCl; a major component of sea salt particles, (NH4)2SO4; a sulfur oxide originated from the marine biotas, and Oxalic acid; a major component among organic carbon (OC) originated from the marine biotas). Activation Rate (AR), which is defined as the ratio of the number concentrations of CCN against TN, varied mainly because of the number-size distribution. Chemical composition was the factor that determined AR values. However, the AR variations caused by changes of the chemical composition were much smaller than those caused changes of the particle size distribution even when Asian dust were observed over the region on 27-29 February. During the long range transport, rapid coagulation among mineral dust, organics and sea salt particles may accelerate the gravitational setting of marine aerosols and supplies the terrestrial substances to the ocean environment.

  16. Accumulation and fragmentation of plastic debris in global environments

    PubMed Central

    Barnes, David K. A.; Galgani, Francois; Thompson, Richard C.; Barlaz, Morton

    2009-01-01

    One of the most ubiquitous and long-lasting recent changes to the surface of our planet is the accumulation and fragmentation of plastics. Within just a few decades since mass production of plastic products commenced in the 1950s, plastic debris has accumulated in terrestrial environments, in the open ocean, on shorelines of even the most remote islands and in the deep sea. Annual clean-up operations, costing millions of pounds sterling, are now organized in many countries and on every continent. Here we document global plastics production and the accumulation of plastic waste. While plastics typically constitute approximately 10 per cent of discarded waste, they represent a much greater proportion of the debris accumulating on shorelines. Mega- and macro-plastics have accumulated in the highest densities in the Northern Hemisphere, adjacent to urban centres, in enclosed seas and at water convergences (fronts). We report lower densities on remote island shores, on the continental shelf seabed and the lowest densities (but still a documented presence) in the deep sea and Southern Ocean. The longevity of plastic is estimated to be hundreds to thousands of years, but is likely to be far longer in deep sea and non-surface polar environments. Plastic debris poses considerable threat by choking and starving wildlife, distributing non-native and potentially harmful organisms, absorbing toxic chemicals and degrading to micro-plastics that may subsequently be ingested. Well-established annual surveys on coasts and at sea have shown that trends in mega- and macro-plastic accumulation rates are no longer uniformly increasing: rather stable, increasing and decreasing trends have all been reported. The average size of plastic particles in the environment seems to be decreasing, and the abundance and global distribution of micro-plastic fragments have increased over the last few decades. However, the environmental consequences of such microscopic debris are still poorly

  17. Visual accumulation tube for size analysis of sands

    USGS Publications Warehouse

    Colby, B.C.; Christensen, R.P.

    1956-01-01

    The visual-accumulation-tube method was developed primarily for making size analyses of the sand fractions of suspended-sediment and bed-material samples. Because the fundamental property governing the motion of a sediment particle in a fluid is believed to be its fall velocity. the analysis is designed to determine the fall-velocity-frequency distribution of the individual particles of the sample. The analysis is based on a stratified sedimentation system in which the sample is introduced at the top of a transparent settling tube containing distilled water. The procedure involves the direct visual tracing of the height of sediment accumulation in a contracted section at the bottom of the tube. A pen records the height on a moving chart. The method is simple and fast, provides a continuous and permanent record, gives highly reproducible results, and accurately determines the fall-velocity characteristics of the sample. The apparatus, procedure, results, and accuracy of the visual-accumulation-tube method for determining the sedimentation-size distribution of sands are presented in this paper.

  18. Chip integrated fuel cell accumulator

    NASA Astrophysics Data System (ADS)

    Frank, M.; Erdler, G.; Frerichs, H.-P.; Müller, C.; Reinecke, H.

    A unique new design of a chip integrated fuel cell accumulator is presented. The system combines an electrolyser and a self-breathing polymer electrolyte membrane (PEM) fuel cell with integrated palladium hydrogen storage on a silicon substrate. Outstanding advantages of this assembly are the fuel cell with integrated hydrogen storage, the possibility of refuelling it by electrolysis and the opportunity of simply refilling the electrolyte by adding water. By applying an electrical current, wiring the palladium hydrogen storage as cathode and the counter-electrode as anode, the electrolyser produces hydrogen at the palladium surface and oxygen at the electrolyser cell anode. The generated hydrogen is absorbed by the palladium electrode and the hydrogen storage is refilled consequently enabling the fuel cell to function.

  19. Potential source regions of dust accumulated in northern Africa

    NASA Astrophysics Data System (ADS)

    Wasowska, S.; Woronko, B.

    2012-04-01

    Sahara is the largest source of the dust in the world. The material sampled from dust storms in Tunisia (Nefta Oasis, El Kantoui Harbor), north Egypt (Alexandria) and Morocco (Mhamid Oasis) (March 2001, March and April 2009) was taken to identify the potential sources of dust accumulation and transport paths in North Africa. The samples were analyzed on grain size, micromorphology of silt grain surfaces in Scanning Electron Microscope (SEM), elemental composition of grains and their surface crusts, loss on ignition, mineralogical composition of samples and carbonate content. Additionally the meteorological situation was analyzed during the dust storm occurrences and preceding periods. The results of grain size analyses show that all studied sediments belong to the small dust type, and dust accumulated in Mhamid is the clay mineral agglomerated (CMA) dust. The source of the CMA are the old dry lake beds. Dust particles are mobilized as aggregates of clay minerals, what is controlled by structure (particle packing) of the original lake sediment, and accumulation is dry and wet as well. The results of the analysis of the quartz grain surface micromorphology, the elemental composition and loss on ignition indicate that dust accumulated in Morocco originated from a relatively homogenous sediment source and, on the other hand, dust found in Alexandria comes from a diversified source. Dust sampled in Tunisia is characterized by the highest content of carbonates and organic matter which suggests the intensive dispelling acting on the weathered material from carbonate rocks and local Mediterranean soil covers rich in CaCO3. The analyses of meteorological conditions during the dust storms and the analyses of the textural characteristics of deposits show that it is highly probable that analysed aeolian dust was transported both for shorter and longer distances. Hypothetic source areas of dust accumulated in Mhamid could be the old ergs, some located 300-500 km away like

  20. Particle beam and crabbing and deflecting structure

    DOEpatents

    Delayen, Jean

    2011-02-08

    A new type of structure for the deflection and crabbing of particle bunches in particle accelerators comprising a number of parallel transverse electromagnetic (TEM)-resonant) lines operating in opposite phase from each other. Such a structure is significantly more compact than conventional crabbing cavities operating the transverse magnetic TM mode, thus allowing low frequency designs.

  1. Model for the incorporation of plant detritus within clastic accumulating interdistributary bays

    SciTech Connect

    Gastaldo, R.A.; McCarroll, S.M.; Douglass, D.P.

    1985-01-01

    Plant-bearing clastic lithologies interpreted as interdistributary bay deposits are reported from rocks Devonian to Holocene in age. Often, these strata preserve accumulations of discrete, laterally continuous leaf beds or coaly horizons. Investigations within two modern inter-distributary bays in the lower delta plain of the Mobile Delta, Alabama have provided insight into the phytotaphonomic processes responsible for the generation of carbonaceous lithologies, coaly horizons and laterally continuous leaf beds. Delvan and Chacalooche Bays lie adjacent to the Tensaw River distributary channel and differ in the mode of clastic and plant detrital accumulation. Delvan Bay, lying west of the distributary channel, is accumulating detritus solely by overbank deposition. Chacaloochee Bay, lying east of the channel, presently is accumulating detritus by active crevasse-splay activity. Plant detritus is accumulating as transported assemblages in both bays, but the mode of preservation differs. In Delvan Bay, the organic component is highly degraded and incorporated within the clastic component resulting in a carbonaceous silt. Little identifiable plant detritus can be recovered. On the other hand, the organic component in Chacaloochee Bay is accumulating in locally restricted allochthonous peat deposits up to 2 m in thickness, and discrete leaf beds generated by flooding events. In addition, autochthonous plant accumulations occur on subaerially and aerially exposed portions of the crevasse. The resultant distribution of plant remains is a complicated array of transported and non-transported organics.

  2. Metabolomic analysis reveals mechanism of antioxidant butylated hydroxyanisole on lipid accumulation in Crypthecodinium cohnii.

    PubMed

    Sui, Xiao; Niu, Xiangfeng; Shi, Mengliang; Pei, Guangsheng; Li, Jinghan; Chen, Lei; Wang, Jiangxin; Zhang, Weiwen

    2014-12-24

    The heterotrophic dinoflagellate alga Crypthecodinium cohnii is known to accumulate lipids with a high fraction of docosahexaenoic acid (DHA). In this study, we first evaluated two antioxidant compounds, butylated hydroxyanisole (BHA) and propyl gallate (PG), for their effects on lipid accumulation in C. cohnii. The results showed that antioxidant BHA could increase lipid accumulation in C. cohnii by 8.80% at a final concentration of 30 μM, while PG had no obvious effect on lipid accumulation at the tested concentrations. To decipher the molecular mechanism responsible for the increased lipid accumulation by BHA, we employed an integrated GC-MS and LC-MS metabolomic approach to determine the time-series metabolic profiles with or without BHA, and then subjected the metabolomic data to a principal component analysis (PCA) and a weighted gene coexpression network analysis (WGCNA) network analyses to identify the key metabolic modules and metabolites possibly relevant to the increased lipid accumulation. LC-MS analysis showed that several metabolites, including NADPH, could be important for the stimulation role of BHA on lipid accumulation. Meanwhile GC-MS and network analyses allowed identification of eight metabolic modules and nine hub metabolites possibly relevant to the stimulation role of BHA in C. cohnii. The study provided a metabolomics view of the BHA mode of action on lipid accumulation in C. cohnii, and the information could be valuable for a better understanding of antioxidant effects on lipid accumulation in other microalgae as well. PMID:25436856

  3. In Situ Solid Particle Generator

    NASA Technical Reports Server (NTRS)

    Agui, Juan H.; Vijayakumar, R.

    2013-01-01

    Particle seeding is a key diagnostic component of filter testing and flow imaging techniques. Typical particle generators rely on pressurized air or gas sources to propel the particles into the flow field. Other techniques involve liquid droplet atomizers. These conventional techniques have drawbacks that include challenging access to the flow field, flow and pressure disturbances to the investigated flow, and they are prohibitive in high-temperature, non-standard, extreme, and closed-system flow conditions and environments. In this concept, the particles are supplied directly within a flow environment. A particle sample cartridge containing the particles is positioned somewhere inside the flow field. The particles are ejected into the flow by mechanical brush/wiper feeding and sieving that takes place within the cartridge chamber. Some aspects of this concept are based on established material handling techniques, but they have not been used previously in the current configuration, in combination with flow seeding concepts, and in the current operational mode. Unlike other particle generation methods, this concept has control over the particle size range ejected, breaks up agglomerates, and is gravity-independent. This makes this device useful for testing in microgravity environments.

  4. Redistribution of particle and antiparticle entanglement in noninertial frames

    SciTech Connect

    Martin-Martinez, Eduardo; Fuentes, Ivette

    2011-05-15

    We analyze the entanglement tradeoff between particle and antiparticle modes of a Dirac field from the perspective of inertial and uniformly accelerated observers. Our results show that a redistribution of entanglement between particle and antiparticle modes plays a key role in the survival of femionic field entanglement in the infinite-acceleration limit.

  5. Guidelines for Waste Accumulation Areas (WAAs)

    SciTech Connect

    Not Available

    1991-07-01

    The purpose of this document is to set conditions for establishing and maintaining areas for the accumulation of hazardous waste at LBL. Areas designed for accumulation of these wastes in quantities greater than 100 kg (220 lb) per month of solid waste or 55 gallons per month of liquid waste are called Waste Accumulation Areas (WAAs). Areas designed for accumulation of wastes in smaller amounts are called Satellite Accumulation Areas (SAAs). This document provides guidelines for employee and organizational responsibilities for WAAs; constructing a WAA; storing waste in a WAA; operating and maintaining a WAA, and responding to spills in a WAA. 4 figs.

  6. Energetic Ion Interactions with Tearing Mode Stability

    NASA Astrophysics Data System (ADS)

    Halfmoon, Michael; Brennan, Dylan

    2015-11-01

    This study focuses on the interactions between energetic ions and pressure-driven, slow growing tearing modes in high beta tokamaks. Previous studies have shown that energetic ions interact with and affect the tearing mode stability, in a mechanism similar to those of ideal MHD instabilities and resistive wall modes. The 2/1 tearing mode is found to be damped or stabilized in the presence of energetic ions, with the most significant effects on the slow-growing resistive mode. To gain an understanding of the underlying physics of these effects, we have investigated a combination of reduced analytics and numerical simulations. In the reduced model, a high aspect ratio, step function equilibrium is investigated, where the dynamics of high-energy ions interacting with the tearing mode is implemented through integration over the pressure step. In the simulations, a series of experimentally relevant D-shaped equilibria with fixed monotonic safety factor and varying peaked pressure profiles is analyzed using the δf hybrid kinetic-mhd code in NIMROD. Results show a damping effect from the ions that is consistent between the reduced model and the simulations. The stabilizing effect is mainly due to trapped particle resonance, causing the tearing mode to have a finite frequency. US DOE Grant DE- SC0004125.

  7. B-modes from cosmic strings

    SciTech Connect

    Pogosian, Levon; Wyman, Mark

    2008-04-15

    Detecting the parity-odd, or B-mode, polarization pattern in the cosmic microwave background radiation due to primordial gravity waves is considered to be the final observational key to confirming the inflationary paradigm. The search for viable models of inflation from particle physics and string theory has (re)discovered another source for B-modes: cosmic strings. Strings naturally generate as much vector-mode perturbation as they do scalar, producing B-mode polarization with a spectrum distinct from that expected from inflation itself. In a large set of models, B-modes arising from cosmic strings are more prominent than those expected from primordial gravity waves. In light of this, we study the physical underpinnings of string-sourced B-modes and the model dependence of the amplitude and shape of the C{sub l}{sup BB} power spectrum. Observational detection of a string-sourced B-mode spectrum would be a direct probe of post-inflationary physics near the grand unified theory (GUT) scale. Conversely, nondetection would put an upper limit on a possible cosmic string tension of G{mu} < or approx. 10{sup -7} within the next three years.

  8. Some Candidates for Solar Gravity Modes

    NASA Astrophysics Data System (ADS)

    Thomson, David J.

    2015-04-01

    Since the accidental discovery of solar modes in space (Thomson,Maclennan, and Lanzerotti, Nature, 1995) work has continued and there are now a few candidates for identified solar gravity modes using charged particles and interplanetary magnetic field data. Contrary to initial expectations, there is a preference for higher-l modes, typically l = 2 to 5.Second, different frequencies are expected at ACE (at L1) and Ulysses, in an almost sidereal solar-polar orbit. Given a candidate detection at ACE where signal-to-noise ratios are higher, one can then shift frequencies by ±32m nHz and test for agreement at Ulysses.Third, the 7.5 degree inclination of the ecliptic on the solar equator splits odd-parity modes at ACE by32 nHz. The two sub-singlets have a defined phase relation that can be used as a further check on parity. Two such modes are G2,-1 at 296.195 uHz and G3,-2 at 296.887 uHz. Both have all 2l+1 singlets detected on both ACE and Ulysses.The 11 singlets of the G5,-1 mode are also all detected above the 99% level. The mode has a center frequency of 383.812 uHz with a1 ≈ 918 nHz.

  9. [Particle emission characteristics of diesel bus fueled with bio-diesel].

    PubMed

    Lou, Di-Ming; Chen, Feng; Hu, Zhi-Yuan; Tan, Pi-Qiang; Hu, Wei

    2013-10-01

    With the use of the Engine Exhaust Particle Sizer (EEPS), a study on the characteristics of particle emissions was carried out on a China-IV diesel bus fueled with blends of 5% , 10% , 20% , 50% bio-diesel transformed from restaurant waste oil and China-IV diesel (marked separately by BD5, BD10, BD20, BD50), pure bio-diesel (BD100) and pure diesel (BD0). The results indicated that particulate number (PN) and mass (PM) emissions of bio-diesel blends increased with the increase in bus speed and acceleration; with increasing bio-diesel content, particulate emissions displayed a relevant declining trend. In different speed ranges, the size distribution of particulate number emissions (PNSD) was bimodal; in different acceleration ranges, PNSD showed a gradual transition from bimodal shape to unimodal when bus operation was switched from decelerating to accelerating status. Bio-diesel blends with higher mixture ratios showed significant reduction in PN emissions for accumulated modes, and the particulate number emission peaks moved towards smaller sizes; but little change was obtained in PN emissions for nuclei modes; reduction also occurred in particle geometric diameter (Dg). PMID:24364288

  10. Sludge accumulation pattern inside oxidation ditch case study.

    PubMed

    Fouad, Moharram; El-Morsy, Ahmed

    2014-01-01

    The sludge accumulation pattern of an oxidation ditch (OD) plant treating municipal wastewater was observed under dry and wet weather conditions, during 3 years of operation. The accumulation patterns along the ditches and their rates were revealed. In addition, the composition of the accumulation was investigated. Finally, the ratio of sand and volatile particles, mixed liquor suspended solids (MLSS), and mixed liquor volatile suspended solids, as well as the removal efficiency were also observed against the accumulated sludge. Further, a laboratory-scale channel was used to investigate the settleability of grit after mixing with variable values of MLSS. The observed results indicated that the economical design and operation of ODs using a velocity value between 0.3-0.35 m/s is not recommended, to avoid the settling of all solids. High values of MLSS and sludge age need high horizontal velocity (more than 0.35 m/s) and more power to avoid settling problems and system failure. The influence of flow velocity on the sludge settleability was studied, enabling better planning of future ditch design and operation. PMID:24960009

  11. Accumulation of silver nanoparticles by cultured primary brain astrocytes

    NASA Astrophysics Data System (ADS)

    Luther, Eva M.; Koehler, Yvonne; Diendorf, Joerg; Epple, Matthias; Dringen, Ralf

    2011-09-01

    Silver nanoparticles (AgNP) are components of various food industry products and are frequently used for medical equipment and materials. Although such particles enter the vertebrate brain, little is known on their biocompatibility for brain cells. To study the consequences of an AgNP exposure of brain cells we have treated astrocyte-rich primary cultures with polyvinylpyrrolidone (PVP)-coated AgNP. The incubation of cultured astrocytes with micromolar concentrations of AgNP for up to 24 h resulted in a time- and concentration-dependent accumulation of silver, but did not compromise the cell viability nor lower the cellular glutathione content. In contrast, the incubation of astrocytes for 4 h with identical amounts of silver as AgNO3 already severely compromised the cell viability and completely deprived the cells of glutathione. The accumulation of AgNP by astrocytes was proportional to the concentration of AgNP applied and significantly lowered by about 30% in the presence of the endocytosis inhibitors chloroquine or amiloride. Incubation at 4 °C reduced the accumulation of AgNP by 80% compared to the values obtained for cells that had been exposed to AgNP at 37 °C. These data demonstrate that viable cultured brain astrocytes efficiently accumulate PVP-coated AgNP in a temperature-dependent process that most likely involves endocytotic pathways.

  12. Magnetic particles

    NASA Technical Reports Server (NTRS)

    Chang, Manchium (Inventor); Colvin, Michael S. (Inventor); Rembaum, Alan (Inventor); Richards, Gil F. (Inventor)

    1987-01-01

    Metal oxide containing polymers and particularly styrene, acrylic or protein polymers containing fine, magnetic iron oxide particles are formed by combining a NO.sub.2 -substituted polymer with an acid such as hydrochloric acid in the presence of metal, particularly iron particles. The iron is oxidized to fine, black Fe.sub.3 O.sub.4 particles which deposit selectively on the polymer particles. Nitrated polymers are formed by reacting functionally substituted, nitrated organic compounds such as trinitrobenzene sulfonate or dinitrofluoro benzene with a functionally coreactive polymer such as an amine modified acrylic polymer or a protein. Other transition metals such as cobalt can also be incorporated into polymers using this method.

  13. Elementary Particles

    ERIC Educational Resources Information Center

    Parham, R.

    1974-01-01

    Presents the text of a speech given to a conference of physics teachers in which the full spectrum of elementary particles is given, along with their classification. Also includes some teaching materials available on this topic. (PEB)

  14. Elementary particles

    NASA Astrophysics Data System (ADS)

    Fritzsch, Harald; Heusch, Karin

    Introduction -- Electrons and atomic nuclei -- Quantum properties of atoms and particles -- The knives of Democritus -- Quarks inside atomic nuclei -- Quantum electrodynamics -- Quantum chromodynamics -- Mesons, baryons, and quarks -- Electroweak interactions -- Grand unification -- Conclusion.

  15. Edge-localized mode avoidance and pedestal structure in I-mode plasmas

    SciTech Connect

    Walk, J. R. 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.; Snyder, P. B.; Osborne, T.; Dominguez, A; Cziegler, I.

    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

  16. Nutrient-contaminant (Pu) plant accumulation model

    SciTech Connect

    Cowan, C.E.; Jenne, E.A.; Simpson, J.C.; Cataldo, D.A.

    1981-12-01

    A model was developed which simulates the movement and daily accumulation of nutrients and contaminants in crop plants resulting from known physiological processes in the plant. In the model, the daily contaminant accumulation is governed by daily increase in plant biomass derived from photosynthesis and by the specified thermodynamic activity of the bioavailable contaminant species in soil or hydroponic solutin. Total accumulation and resulting concentration in the plant's root, stem and branch, leaf, and reproductive compartments can be simulated any time during the growing season. Parameters were estimated from data on plutonium accumulation in soybeans and the model was calibrated against this same data set. The plutonium distribution in the plant was found to be most sensitive to parameters related to leaf accumulation. Contamination at different times during the growing season resulted in a large change in predicted leaf accumulation but very little change in predicted accumulation in other plant parts except when contamination occurred very late in the growing season.

  17. Dual-Mode Combustor

    NASA Technical Reports Server (NTRS)

    Trefny, Charles J (Inventor); Dippold, Vance F (Inventor)

    2013-01-01

    A new dual-mode ramjet combustor used for operation over a wide flight Mach number range is described. Subsonic combustion mode is usable to lower flight Mach numbers than current dual-mode scramjets. High speed mode is characterized by supersonic combustion in a free-jet that traverses the subsonic combustion chamber to a variable nozzle throat. Although a variable combustor exit aperture is required, the need for fuel staging to accommodate the combustion process is eliminated. Local heating from shock-boundary-layer interactions on combustor walls is also eliminated.

  18. Auroral particles

    NASA Technical Reports Server (NTRS)

    Evans, David S.

    1987-01-01

    The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries.

  19. Composition of 15-85 nm particles in marine air

    NASA Astrophysics Data System (ADS)

    Lawler, M. J.; Whitehead, J.; O'Dowd, C.; Monahan, C.; McFiggans, G.; Smith, J. N.

    2014-11-01

    The chemical composition of 15-85 nm diameter particles was measured at Mace Head, Ireland, during May 2011 using the TDCIMS (thermal desorption chemical ionization mass spectrometer). Measurable levels of chloride, sodium, and sulfate were present in essentially all collected samples of these particles at this coastal Atlantic site. Acetaldehyde and benzoic acid were also frequently detected. Concomitant particle hygroscopicity observations usually showed a sea-salt mode and a lower hygroscopicity mode with growth factors near to that of ammonium sulfate. There were many periods lasting from hours to about 2 days during which the 10-60 nm particle number increased dramatically in polar oceanic air. These periods were correlated with the presence of benzoic acid in the particles and an increase in the number of lower hygroscopicity mode particles. Very small (< 10 nm) particles were also present, suggesting that new particle formation contributed to these nanoparticle enhancement events.

  20. [Size distributions of aerosol particles and the impact on visibility in winter of Nanjing].

    PubMed

    Shang, Qian; Li, Zi-Hua; Yang, Jun; Pu, Mei-Juan

    2011-09-01

    increased in comparison with sunny day. Scavenging action of rain and fog to particles of different sizes from high to low was that coarse particles > nuclei mode particles > accumulation mode particles. In haze day, the peak of number concentration distribution moved toward a higher value. Compared to sunny day, the number concentration of aerosol particles ranging from 0.03 to 0.1 microm decreased, and aerosol particles between 0.1 and 2.7 microm increased in haze day. Based on Mie theory, the correlation between visibility and surface area concentration with different particle sizes indicated that particles between 0.1 and 2 microm in diameter shows a good correlation with visibility, which was the major contributor to visibility degradation in Nanjing. PMID:22165248

  1. Particle concentrations and number size distributions in the planetary boundary layer derived from airship based measurements

    NASA Astrophysics Data System (ADS)

    Tillmann, Ralf; Zhao, Defeng; Ehn, Mikael; Hofzumahaus, Andreas; Holland, Frank; Rohrer, Franz; Kiendler-Scharr, Astrid; Wahner, Andreas

    2014-05-01

    Atmospheric particles play a key role for regional and global climate due to their direct and indirect radiative forcing effects. The concentration and size of the particles are important variables to these effects. Within the continental planetary boundary layer (PBL) the particle number size distribution is influenced by meteorological parameters, local sinks and sources resulting in variable spatial distributions. However, measurements of particle number size distributions over a broad vertical range of the PBL are rare. The airship ZEPPELIN NT is an ideal platform to measure atmospheric aerosols on a regional scale within an altitude range up to 1000 m. For campaigns in the Netherlands, Northern Italy and South Finland in 2012 and 2013 the airship was deployed with a wide range of instruments, including measurements of different trace gases, short lived radicals, solar radiation, aerosols and meteorological parameters. Flights were carried out at different times of the day to investigate the influence of the diurnal evolution of the PBL on atmospheric trace gases and aerosols. During night and early morning hours the concentration and size distribution of atmospheric particles were found to be strongly influenced by the layered structure of the PBL, i.e. the nocturnal boundary layer and the residual layer. Within the residual layer particle concentrations stay relatively constant as this layer is decoupled from ground sources. The particles persist in the accumulation mode as expected for an aged aerosol. In the nocturnal boundary layer particle concentrations and size are more dynamic with higher concentrations than in the residual layer. A few hours after sunrise, the layered structure of the PBL intermixes. During daytime the PBL is well mixed and a negative concentration gradient with increasing height is observed. Several height profiles at different times of the day and at different locations in Europe were measured. The aerosol measurements will be

  2. Hygroscopic growth of urban aerosol particles in Beijing (China) during wintertime: a comparison of three experimental methods

    NASA Astrophysics Data System (ADS)

    Meier, J.; Wehner, B.; Massling, A.; Birmili, W.; Nowak, A.; Gnauk, T.; Brüggemann, E.; Herrmann, H.; Min, H.; Wiedensohler, A.

    2009-03-01

    This paper presents hygroscopicity measurements of aerosol particles in the urban atmosphere of Beijing carried out in January 2005. Therefore, three different methods were used: 1) Combining Humidifying Differential Mobility Particle Sizer (H-DMPS) and Twin Differential Mobility Particle Sizer (TDMPS) measurements; 2) Hygroscopicity Tandem Differential Mobility Analyzer (H-TDMA) technique; 3) Calculating hygroscopic growth factors on the basis of a solubility model quantified by Micro Orifice Uniform Deposit Impactor (MOUDI) samples. Particle number size distributions from H-DMPS and TDMPS were evaluated to derive size-resolved descriptive hygroscopic growth factors (DHGF) of 30-400 nm particles at relative humidities (RH) of 55%, 77% and 90%. The atmospheric particles in Beijing were rather hydrophobic, with a maximum growth factor in the accumulation mode around 1.40 (±0.03) at 90% RH. The descriptive hygroscopic growth factors decreased significantly towards the lower measurement limit (1.04 (±0.15) at Dp=30 nm). A good agreement was found between the DHGFs and the H-TDMA-derived hygroscopic growth factors in the accumulation mode (100-400 nm), the DHGFs underestimated the values from the H-TDMA in the Aitken mode (<100 nm) by up to 0.1 at 90% RH. The calculation of hygroscopic growth factors based on the measured chemical composition showed that different modes of combining the inorganic ions caused a variation in growth factor of 0.1 at 90% RH. The solubility model was able to reproduce the size-dependent trend in the growth factor found by the other methods. In two cases of ion-dominated aerosol, the composition-derived growth factors tended to agree (±0.05) or underestimate (up to 0.1) the values measured by the other two methods. In the case of the organic-dominated aerosol, the reverse was true, with an overestimation of up to 0.2. The results shed light on the real experimental and methodological uncertainties that are still connected with the

  3. Neutral particle lithography

    NASA Astrophysics Data System (ADS)

    Craver, Barry Paul

    Neutral particle lithography (NPL) is a high resolution, proximity exposure technique where a broad beam of energetic neutral particles floods a stencil mask and transmitted beamlets transfer the mask pattern to resist on a substrate, such that each feature is printed in parallel, rather than in the serial manner of electron beam lithography. It preserves the advantages of ion beam lithography (IBL), including extremely large depth-of-field, sub-5 nm resist scattering, and the near absence of diffraction, yet is intrinsically immune to charge-related artifacts including line-edge roughness and pattern placement errors due to charge accumulation on the mask and substrate. In our experiments, a neutral particle beam is formed by passing an ion beam (e.g., 30 keV He+) through a high pressure helium gas cell (e.g., 100 mTorr) to convert the ions to energetic neutrals through charge transfer scattering. The resolution of NPL is generally superior to that of IBL for applications involving insulating substrates, large proximity gaps, and ultra-small features. High accuracy stepped exposures with energetic neutral particles, where magnetic or electrostatic deflection is impossible, have been obtained by clamping the mask to the wafer, setting the proximity gap with a suitable spacer, and mechanically inclining the mask/wafer stack relative to the beam. This approach is remarkably insensitive to vibration and thermal drift; nanometer scale image offsets have been obtained with +/-2 nm placement accuracy for experiments lasting over one hour. Using this nanostepping technique, linewidth versus dose curves were obtained, from which the NPL lithographic blur was determined as 4.4+/-1.4 nm (1sigma), which is 2-3 times smaller than the blur of electron beam lithography. Neutral particle lithography has the potential to form high density, periodic patterns with sub-10 nm resolution.

  4. Coupled Dust-Lattice Modes in Magnetized Complex Plasmas

    SciTech Connect

    Farokhi, B.; Shahmansouri, M.

    2008-09-07

    Dust lattice wave modes in a one dimensional plasma crystal (formed by paramagnetic dust particles) suspended in the plasma sheath are studied. The ion flow in the sheath introduces 'ion wakes' below the crystal particles. The wave dispersion relations are found under the influence of inhomogeneous magnetic field, wake charge effect and equilibrium charge gradient. The expression for the wave dispersion relations clearly show that three branches exist as a result of the coupling of longitudinal and transverse modes due to the Lorenz forces, charge gradient and wake charge effect. We observe a new coupling between the dust lattice modes, which have not reported so far.

  5. Kinetic effect of toroidal rotation on the geodesic acoustic mode

    SciTech Connect

    Guo, W. Ye, L.; Zhou, D.; Xiao, X.; Wang, S.

    2015-01-15

    Kinetic effects of the toroidal rotation on the geodesic acoustic mode are theoretically investigated. It is found that when the toroidal rotation increases, the damping rate increases in the weak rotation regime due to the rotation enhancement of wave-particle interaction, and it decreases in the strong rotation regime due to the reduction of the number of resonant particles. Theoretical results are consistent with the behaviors of the geodesic acoustic mode recently observed in DIII-D and ASDEX-Upgrade. The kinetic damping effect of the rotation on the geodesic acoustic mode may shed light on the regulation of turbulence through the controlling the toroidal rotation.

  6. Diffraction of entangled particles by light gratings

    NASA Astrophysics Data System (ADS)

    Sancho, Pedro

    2015-04-01

    We analyze the diffraction regime of the Kapitza-Dirac effect for particles entangled in momentum. The detection patterns show two-particle interferences. In the single-mode case we identify a discontinuity in the set of joint detection probabilities, associated with the disconnected character of the space of non-separable states. For Gaussian multi-mode states we derive the diffraction patterns, providing an example of the dependence of the light-matter interaction on entanglement. When the particles are identical, we can explore the relation between exchange and entanglement effects. We find a complementary behavior between overlapping and Schmidt's number. In particular, symmetric entanglement can cancel the exchange effects.

  7. Beam Distribution Modification By Alfven Modes

    SciTech Connect

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

    2010-01-25

    Modification of a deuterium beam distribution in the presence of low amplitude Toroidal Alfven (TAE) eigenmodes and Reversed Shear Alfven (RSAE) eigenmodes in a toroidal magnetic confinement device is examined. 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 transport, and that the experimental amplitudes are only slightly above this threshold. The modes produce a substantial central flattening of the beam distribution.

  8. Beam Distribution Modification by Alfven Modes

    SciTech Connect

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

    2010-04-03

    Modification of a deuterium beam distribution in the presence of low amplitude Toroidal Alfven (TAE) eigenmodes and Reversed Shear Alfven (RSAE) eigenmodes in a toroidal magnetic confinement device is examined. 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 transport, and that the experimental amplitudes are only slightly above this threshold. The modes produce a substantial central flattening of the beam distribution.

  9. Drift Mode Calculations in Nonaxisymmetric Geometry

    SciTech Connect

    G. Rewoldt; L.-P. Ku; W.A. Cooper; W.M. Tang

    1999-07-01

    A fully kinetic assessment of the stability properties of toroidal drift modes has been obtained for nonaxisymmetric (stellarator) geometry, in the electrostatic limit. This calculation is a comprehensive solution of the linearized gyrokinetic equation, using the lowest-order ''ballooning representation'' for high toroidal mode number instabilities, with a model collision operator. Results for toroidal drift waves destabilized by temperature gradients and/or trapped particle dynamics are presented, using three-dimensional magnetohydrodynamic equilibria generated as part of a design effort for a quasiaxisymmetric stellarator. Comparisons of these results with those obtained for typical tokamak cases indicate that the basic trends are similar.

  10. Organic Nitrate Contribution to New Particle Formation and Growth in Secondary Organic Aerosols from α-Pinene Ozonolysis.

    PubMed

    Berkemeier, Thomas; Ammann, Markus; Mentel, Thomas F; Pöschl, Ulrich; Shiraiwa, Manabu

    2016-06-21

    The chemical kinetics of organic nitrate production during new particle formation and growth of secondary organic aerosols (SOA) were investigated using the short-lived radioactive tracer (13)N in flow-reactor studies of α-pinene oxidation with ozone. Direct and quantitative measurements of the nitrogen content indicate that organic nitrates accounted for ∼40% of SOA mass during initial particle formation, decreasing to ∼15% upon particle growth to the accumulation-mode size range (>100 nm). Experiments with OH scavengers and kinetic model results suggest that organic peroxy radicals formed by α-pinene reacting with secondary OH from ozonolysis are key intermediates in the organic nitrate formation process. The direct reaction of α-pinene with NO3 was found to be less important for particle-phase organic nitrate formation. The nitrogen content of SOA particles decreased slightly upon increase of relative humidity up to 80%. The experiments show a tight correlation between organic nitrate content and SOA particle-number concentrations, implying that the condensing organic nitrates are among the extremely low volatility organic compounds (ELVOC) that may play an important role in the nucleation and growth of atmospheric nanoparticles. PMID:27219077

  11. Ballooning mode spectrum in general toroidal systems

    SciTech Connect

    Dewar, R.L.; Glasser, A.H.

    1982-04-01

    A WKB formalism for constructing normal modes of short-wavelength ideal hydromagnetic, pressure-driven instabilities (ballooning modes) in general toroidal magnetic containment devices with sheared magnetic fields is developed. No incompressibility approximation is made. A dispersion relation is obtained from the eigenvalues of a fourth order system of ordinary differential equations to be solved by integrating along a line of force. Higher order calculations are performed to find the amplitude equation and the phase change at a caustic. These conform to typical WKB results. In axisymmetric systems, the ray equations are integrable, and semiclassical quantization leads to a growth rate spectrum consisting of an infinity of discrete eigenvalues, bounded above by an accumulation point. However, each eigenvalue is infinitely degenerate. In the nonaxisymmetric case, the rays are unbounded in a four dimensional phase space, and semiclassical quantization breaks down, leading to broadening of the discrete eigenvalues and accumulation point of the axisymmetric case into continuum bands. Analysis of a model problem indicates that the broadening of the discrete eigenvalues is numerically very small, the dominant effect being broadening of the accumulation point.

  12. Natural radionuclide accumulation by raindrops

    NASA Astrophysics Data System (ADS)

    Gusev, Anatoly; Martin, Inacio; Shkevov, Rumen; Alves, Mauro

    2016-07-01

    The laboratory of environmental radiation of ITA (São José dos Campos, 23°11'11″S, 45°52'43″W, 650 MAMSL) performs simultaneous monitoring of a natural radiation background and meteorological parameters. A time resolution of up to 1 minute allows a detailed comparison of changes in meteorological parameters with those of a concentration of ambient radon progenies in the atmosphere. Results of a study of variation of a fallout of radon progenies ^{214}Pb and ^{214}Bi concomitanting rainfalls are present. The radionuclide fallout rate is reconstructed from the observed gamma rate through a simulation of the first kind Volterra integral equation with difference kernel, determined by ratio of precipitating rates of 214Pb and 214Bi and their decay half times. An original straightforward step-by-step procedure was used for the numerical solution of the equation. The radionuclide concentration in the rainwater is calculated as a ratio of the reconstructed fallout to the measured rainfall. It was observed that the radionuclide fallout rate increases as the rainfall one in approximately power 0.6, i.e. the same as the mean raindrop volume. The concentration thereafter decreases as the rainfall rate in power 0.4. A numerical simulation of the process of accumulation of the radionuclides during diffusion and coalescence drop growth and aerosol scavenging during a passage from a cloud to the ground was performed. The results of the simulations agree with the experimental data.

  13. Environmental applications of the particle analysis system

    SciTech Connect

    Moritz, E.J.; Hoffman, C.R.

    1993-09-28

    This study demonstrates the applicability of particle counting technology for analysis of various water treatment systems at the Rocky Flats Plant. The Particle Analysis System described in this study determined the water quality of samples from environmental remediation, stormwater treatment, and drinking water treatment operations. Samples were measured in either discrete or on-line mode. This data showed filtration efficiencies, particle counts, particle size distributions, and real-time treatment system performance. Particle counting proved more sensitive than the turbidimetric measurement technique commonly used by the water treatment industry. Particle counting is a two-dimensional measurement of counts and sizes, whereas turbidity is a one-dimensional measurement of water clarity. Samples showing identical turbidities could be distinguished easily with the Particle Analysis System. The Particle Analysis System proved to be an efficient and reliable water quality measurement tool, and it is applicable to a variety of water treatment systems at the Rocky Flats Plant.

  14. Tearing Modes in Tokamaks

    NASA Astrophysics Data System (ADS)

    White, R. B.

    2008-05-01

    This lecture gives a basic introduction to magnetic £elds, magnetic surface destruction, toroidal equilibrium and tearing modes in a tokamak, including the linear and nonlinear development of these modes and their modi£cation by current drive and bootstrap current, and sawtooth oscillations and disruptions.

  15. Whispering Gallery Mode Spectroscopy as a Diagnostic for Dusty Plasmas

    SciTech Connect

    Thieme, G.; Basner, R.; Ehlbeck, J.; Roepcke, J.; Maurer, H.; Kersten, H.; Davies, P. B.

    2008-09-07

    Whispering-gallery-mode spectroscopy is being assessed as a diagnostic method for the characterisation of size and chemical composition of spherical particles levitated in a plasma. With a pulsed laser whispering gallery modes (cavity resonances) are excited in individual microspheres leading to enhanced Raman scattering or fluorescence at characteristic wavelengths. This method can be used to gain specific information from the particle surface and is thus of great interest for the characterisation of layers deposited on microparticles, e.g. in molecular plasmas. We present investigations of different microparticles in air and results from fluorescent particles levitated in an Argon rf plasma.

  16. Mode decomposition evolution equations

    PubMed Central

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2011-01-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  17. Relation between energetic and standard geodesic acoustic modes

    SciTech Connect

    Girardo, Jean-Baptiste; Dumont, Rémi; Garbet, Xavier; Sarazin, Yanick; Zarzoso, David; Sharapov, Sergei

    2014-09-15

    Geodesic Acoustic Modes (GAMs) are electrostatic, axisymmetric modes which are non-linearly excited by turbulence. They can also be excited linearly by fast-particles; they are then called Energetic-particle-driven GAMs (EGAMs). Do GAMs and EGAMs belong to the same mode branch? Through a linear, analytical model, in which the fast particles are represented by a Maxwellian bump-on-tail distribution function, we find that the answer depends on several parameters. For low values of the safety factor q and for high values of the fast ion energy, the EGAM originates from the GAM. On the contrary, for high values of q and for low values of the fast ion energy, the GAM is not the mode which becomes unstable when fast particles are added: the EGAM then originates from a distinct mode, which is strongly damped in the absence of fast particles. The impact of other parameters is further explored: ratio of the ion temperature to the electron temperature, width of the fast particle distribution, mass and charge of the fast ions. The ratio between the EGAM and the GAM frequencies was found in experiments (DIII-D) and in non-linear numerical simulations (code GYSELA) to be close to 1/2: the present analytical study allows one to recover this ratio.

  18. Zero-mode waveguides

    DOEpatents

    Levene, Michael J.; Korlach, Jonas; Turner, Stephen W.; Craighead, Harold G.; Webb, Watt W.

    2007-02-20

    The present invention is directed to a method and an apparatus for analysis of an analyte. The method involves providing a zero-mode waveguide which includes a cladding surrounding a core where the cladding is configured to preclude propagation of electromagnetic energy of a frequency less than a cutoff frequency longitudinally through the core of the zero-mode waveguide. The analyte is positioned in the core of the zero-mode waveguide and is then subjected, in the core of the zero-mode waveguide, to activating electromagnetic radiation of a frequency less than the cut-off frequency under conditions effective to permit analysis of the analyte in an effective observation volume which is more compact than if the analysis were carried out in the absence of the zero-mode waveguide.

  19. Characterisation of sub-micron particle number concentrations and formation events in the western Bushveld Igneous Complex, South Africa

    NASA Astrophysics Data System (ADS)

    Hirsikko, A.; Vakkari, V.; Tiitta, P.; Manninen, H. E.; Gagné, S.; Laakso, H.; Kulmala, M.; Mirme, A.; Mirme, S.; Mabaso, D.; Beukes, J. P.; Laakso, L.

    2012-05-01

    South Africa holds significant mineral resources, with a substantial fraction of these reserves occurring and being processed in a large geological structure termed the Bushveld Igneous Complex (BIC). The area is also highly populated by informal, semi-formal and formal residential developments. However, knowledge of air quality and research related to the atmosphere is still very limited in the area. In order to investigate the characteristics and processes affecting sub-micron particle number concentrations and formation events, air ion and aerosol particle size distributions and number concentrations, together with meteorological parameters, trace gases and particulate matter (PM) were measured for over two years at Marikana in the heart of the western BIC. The observations showed that trace gas (i.e. SO2, NOx, CO) and black carbon concentrations were relatively high, but in general within the limits of local air quality standards. The area was characterised by very high condensation sink due to background aerosol particles, PM10 and O3 concentration. The results indicated that high amounts of Aitken and accumulation mode particles originated from domestic burning for heating and cooking in the morning and evening, while during daytime SO2-based nucleation followed by the growth by condensation of vapours from industrial, residential and natural sources was the most probable source for large number concentrations of nucleation and Aitken mode particles. Nucleation event day frequency was extremely high, i.e. 86% of the analysed days, which to the knowledge of the authors is the highest frequency ever reported. The air mass back trajectory and wind direction analyses showed that the secondary particle formation was influenced both by local and regional pollution and vapour sources. Therefore, our observation of the annual cycle and magnitude of the particle formation and growth rates during nucleation events were similar to results previously published for a semi

  20. A PEMS study of the emissions of gaseous pollutants and ultrafine particles from gasoline- and diesel-fueled vehicles

    NASA Astrophysics Data System (ADS)

    Huang, Cheng; Lou, Diming; Hu, Zhiyuan; Feng, Qian; Chen, Yiran; Chen, Changhong; Tan, Piqiang; Yao, Di

    2013-10-01

    On-road emission measurements of gasoline- and diesel-fueled vehicles were conducted by a portable emission measurement system (PEMS) in Shanghai, China. Horiba OBS 2200 and TSI EEPS 3090 were employed to detect gaseous and ultrafine particle emissions during the tests. The driving-based emission factors of gaseous pollutants and particle mass and number were obtained on various road types. The average NOx emission factors of the diesel bus, diesel car, and gasoline car were 8.86, 0.68, and 0.17 g km-1, all of which were in excess of their emission limits. The particle number emi