WorldWideScience

Sample records for incident particle distribution

  1. Influence of the incident particle energy on the fission product mass distribution

    International Nuclear Information System (INIS)

    Gomes, I. C.

    1998-01-01

    For 238 U targets and the five elements considered here, the best yields of neutron-rich isotopes are obtained from neutrons in the 2-20 MeV range. High energy beams of neutrons, protons, and deuterons have comparable integral yields per element to neutrons below 20 MeV, but the distributions are peaked at lower neutron numbers. This is presumably due to a higher neutron multiplicity in the pre-equilibrium stage and/or the compound nucleus/fission stage. For 235 U targets there are high yields predicted especially for thermal neutrons, and also for the fast neutron spectrum. For the high energy neutrons, protons, and deuterons 235 U has no advantage over 238 U. A detailed comparison of the relative advantages of 235 U and 238 U for radioactive beam applications is beyond the scope of this study and will be addressed in the future. The present work is the first step of a more detailed analysis of various possible one- and two-step target geometry calculated with the LAHET code system. It is intended to serve as a guide in choosing geometry and beams for future studies. It is desirable to extend this study to higher beam energies, e.g. 200 to 1000 MeV, but at this time there is very little data against which to benchmark the analysis. Additional data would also permit comparisons of isotope yields beyond the tails of the distributions presented here, to even more neutron rich isotopes

  2. Pseudorapidity distributions of charged particles as a function of centrality in Pb-Pb collisions at 158 and 40 GeV per nucleon incident energy

    CERN Document Server

    Abreu, M C; Alexa, C; Arnaldi, R; Ataian, M R; Baglin, C; Baldit, A; Bedjidian, Marc; Beolè, S; Boldea, V; Bordalo, P; Borges, G; Bussière, A; Capelli, L; Castanier, C; Castor, J I; Chaurand, B; Chevrot, I; Cheynis, B; Chiavassa, E; Cicalò, C; Claudino, T; Comets, M P; Constans, N; Constantinescu, S; Cortese, P; De Falco, A; De Marco, N; Dellacasa, G; Devaux, A; Dita, S; Drapier, O; Ducroux, L; Espagnon, B; Fargeix, J; Force, P; Gallio, M; Gavrilov, Yu K; Gerschel, C; Giubellino, P; Golubeva, M B; Gonin, M; Grigorian, A A; Grigorian, S; Grossiord, J Y; Guber, F F; Guichard, A; Gulkanian, H R; Hakobyan, R S; Haroutunian, R; Idzik, M; Jouan, D; Karavitcheva, T L; Kluberg, L; Kurepin, A B; Le Bornec, Y; Lourenço, C; Macciotta, P; MacCormick, M; Marzari-Chiesa, A; Masera, M; Masoni, A; Monteno, M; Musso, A; Petiau, P; Piccotti, A; Pizzi, J R; Prado da Silva, W L; Prino, F; Puddu, G; Quintans, C; Ramello, L; Ramos, S; Rato-Mendes, P; Riccati, L; Romana, A; Santos, H; Saturnini, P; Scalas, E; Scomparin, E; Serci, S; Shahoyan, R; Sigaudo, F; Silva, S; Sitta, M; Sonderegger, P; Tarrago, X; Topilskaya, N S; Usai, G L; Vercellin, Ermanno; Villatte, L; Willis, N

    2002-01-01

    The charged particle distributions $dN_{ch}/d\\eta$ have been measured by the NA50 experiment in Pb--Pb collisions at the CERN SPS. Measurements have been done at incident energies of 158 and 40 GeV per nucleon over a broad impact parameter range. Results obtained with two independent centrality estimators, namely the neutral transverse energy $E_T$ and the forward energy $E_{ZDC}$, are reported.}

  3. A study of the angular distribution of the secondary particles of anti pAg/Br reactions at 1.4 GeV/c incident momentum observed in photographic emulsion

    International Nuclear Information System (INIS)

    Breivik, F.O.; Jacobsen, T.; Soerensen, S.O.

    1983-04-01

    Some features of anti pAg/Br reactions at 1.4 GeV/c incident momentum are studied by means of the emulsion technique. The distributions of the number of charged particles/event are presented. The angular distributions indicate som anisotropic process in the nuclear matter, possibly shock waves, and some back-to-back emission

  4. On the momentum distribution of particles participating in nuclear

    Indian Academy of Sciences (India)

    Various momentum constraints were imposed to get better insight into the stopping. The comparison of measured and calculated values of stopping for protons reveals the significance of these constraints. Maximum stopping is obtained for the particles lying in the lowest range of the momentum distribution at all incident ...

  5. Transverse momentum distributions of identified particles produced ...

    Indian Academy of Sciences (India)

    We assume that the transverse momentum distributions of identified particles measured in final state are contributed by a few energy sources which can be regarded as partons or quarks in the interacting system. The particle is contributed by each source with gluons which have transverse momentum distributions in an ...

  6. Preliminary proposals for extending the ENDF format to allow incident charged particles and energy-angle correlation for emitted particles

    International Nuclear Information System (INIS)

    MacFarlane, R.E.; Stewart, L.; Hale, G.M.; Dunford, C.L.

    1984-04-01

    This rewrite of Data Formats and Procedures for the Evaluated Nuclear Data File, ENDF pertains to the latest version, ENDF/B-VI. Earlier versions provided representations for neutron cross sections and distributions, photon production from neutron reactions, a limited amount of charged-particle production from neutron reactions, photo-atomic interaction data, thermal neutron scattering data, and radionuclide production and decay data (including fission products). This version allows higher incident energies, adds more complete descriptions of the distributions of emitted particles, and provides for incident charged particles and photo-nuclear data by partitioning the ENDF library into sublibraries. Decay data, fission product yield data, thermal scattering data, and photo-atomic data have also been formally placed in sublibraries. In addition, this rewrite represents an extensive update to the Version V manual

  7. Statistical distribution of quantum particles

    Indian Academy of Sciences (India)

    In this work, the statistical distribution functions for boson, fermions and their mixtures have been derived and it is found that distribution functions follow the symmetry features of β distribution. If occupation index is greater than unity, then it is easy in the present approach to visualise condensations in terms of intermediate ...

  8. Statistical distribution of quantum particles

    Science.gov (United States)

    Khasare, S. B.; Khasare, Shashank S.

    2018-03-01

    In this work, the statistical distribution functions for boson, fermions and their mixtures have been derived and it is found that distribution functions follow the symmetry features of β distribution. If occupation index is greater than unity, then it is easy in the present approach to visualise condensations in terms of intermediate values of mixing parameters. There are some applications of intermediate values of mixing parameters.

  9. Statistical distribution of quantum particles

    Indian Academy of Sciences (India)

    S B Khasare

    2018-02-08

    Feb 8, 2018 ... One of the motivation to study intermediate statistics is to construct fault tolerant quantum computer using an approach such as topological quantum computation [3] that relies on the existence of topological states of mat- ter whose quasiparticle excitations are neither bosons nor fermions but are particles ...

  10. Radial particle distributions in PARMILA simulation beams

    International Nuclear Information System (INIS)

    Boicourt, G.P.

    1984-03-01

    The estimation of beam spill in particle accelerators is becoming of greater importance as higher current designs are being funded. To the present, no numerical method for predicting beam-spill has been available. In this paper, we present an approach to the loss-estimation problem that uses probability distributions fitted to particle-simulation beams. The properties of the PARMILA code's radial particle distribution are discussed, and a broad class of probability distributions are examined to check their ability to fit it. The possibility that the PARMILA distribution is a mixture is discussed, and a fitting distribution consisting of a mixture of two generalized gamma distributions is found. An efficient algorithm to accomplish the fit is presented. Examples of the relative prediction of beam spill are given. 26 references, 18 figures, 1 table

  11. Suspended sediment concentration and particle size distribution ...

    Indian Academy of Sciences (India)

    , zinc and nickel) transported in ... Suspended sediment concentration; heavy metal concentration; regression model; particle size distribution;. Kojour watershed; Iran. ..... contaminants in a uranium mine pite–Lake; Water Res. 39 3055–3061.

  12. Chaotic distributions for relativistic particles

    OpenAIRE

    Mustafa, Dawan; Wennberg, Bernt

    2015-01-01

    We study a modified Kac model where the classical kinetic energy is replaced by an arbitrary energy function $\\phi(v)$, $v \\in \\mathbb{R}$. The aim of this paper is to show that the uniform density with respect to the microcanonical measure is $Ce^{-z_0\\phi(v)}$-chaotic, $C,z_0 \\in \\mathbb{R}_+$. The kinetic energy for relativistic particles is a special case. A generalization to the case $v\\in \\mathbb{R}^d$ which involves conservation momentum is also formally discussed.

  13. Statistical distribution of quantum particles

    Indian Academy of Sciences (India)

    S B Khasare

    2018-02-08

    Feb 8, 2018 ... The rest of the paper is organised as follows. In §2, we introduce the basic definition of thermodynamic prob- ability W. Section 3 gives the derivation and graphical plot for occupation index in terms of parameter μb using multivariate β distribution. The application of inter- mediate statistics is discussed in §4 ...

  14. Particle size distribution instrument. Topical report 13

    Energy Technology Data Exchange (ETDEWEB)

    Okhuysen, W.; Gassaway, J.D.

    1995-04-01

    The development of an instrument to measure the concentration of particles in gas is described in this report. An in situ instrument was designed and constructed which sizes individual particles and counts the number of occurrences for several size classes. Although this instrument was designed to detect the size distribution of slag and seed particles generated at an experimental coal-fired magnetohydrodynamic power facility, it can be used as a nonintrusive diagnostic tool for other hostile industrial processes involving the formation and growth of particulates. Two of the techniques developed are extensions of the widely used crossed beam velocimeter, providing simultaneous measurement of the size distribution and velocity of articles.

  15. 49 CFR 191.9 - Distribution system: Incident report.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Distribution system: Incident report. 191.9... CONDITION REPORTS § 191.9 Distribution system: Incident report. (a) Except as provided in paragraph (c) of... report required by this section need not be submitted with respect to master meter systems or LNG...

  16. SU-E-T-753: Three-Dimensional Dose Distributions of Incident Proton Particle in the Polymer Gel Dosimeter and the Radiochromic Gel Dosimeter: A Simulation Study with MCNP Code

    International Nuclear Information System (INIS)

    Park, M; Kim, G; Ji, Y; Kim, K; Park, S; Jung, H

    2015-01-01

    Purpose: The purpose of this study is to estimate the three-dimensional dose distributions in the polymer and the radiochromic gel dosimeter, and to identify the detectability of both gel dosimeters by comparing with the water phantom in case of irradiating the proton particles. Methods: The normoxic polymer gel and the LCV micelle radiochromic gel were used in this study. The densities of polymer and the radiochromic gel dosimeter were 1.024 and 1.005 g/cm 3 , respectively. The dose distributions of protons in the polymer and radiochromic gel were simulated using Monte Carlo radiation transport code (MCNPX, Los Alamos National Laboratory). The shape of phantom irradiated by proton particles was a hexahedron with the dimension of 12.4 × 12.4 × 15.0 cm 3 . The energies of proton beam were 50, 80, and 140 MeV energies were directed to top of the surface of phantom. The cross-sectional view of proton dose distribution in both gel dosimeters was estimated with the water phantom and evaluated by the gamma evaluation method. In addition, the absorbed dose(Gy) was also calculated for evaluating the proton detectability. Results: The evaluation results show that dose distributions in both gel dosimeters at intermediated section and Bragg-peak region are similar with that of the water phantom. At entrance section, however, inconsistencies of dose distribution are represented, compared with water. The relative absorbed doses in radiochromic and polymer gel dosimeter were represented to be 0.47 % and 2.26 % difference, respectively. These results show that the radiochromic gel dosimeter was better matched than the water phantom in the absorbed dose evaluation. Conclusion: The polymer and the radiochromic gel dosimeter show similar characteristics in dose distributions for the proton beams at intermediate section and Bragg-peak region. Moreover the calculated absorbed dose in both gel dosimeters represents similar tendency by comparing with that in water phantom

  17. Suspended sediment concentration and particle size distribution ...

    Indian Academy of Sciences (India)

    The relationship between SSC and particle size distribution (PSD) were correlated with HMC by using bivariate and multivariate regression models. Proposed models were then selected based on statistical criteria. The results showed high correlation between dissolved and particulate chromium content with efficiency ...

  18. Particle Distribution Modification by Low Amplitude Modes

    International Nuclear Information System (INIS)

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

    2009-01-01

    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.

  19. Transverse momentum distributions of identified particles produced ...

    Indian Academy of Sciences (India)

    ... sources which can be regarded as partons or quarks in the interacting system. The particle is contributed by each source with gluons which have transverse momentum distributions in an exponential form. The modelling results are compared and found to be in agreement with the experimental data at high energies.

  20. Continuous particle spectra and their angular distributions

    International Nuclear Information System (INIS)

    Sastry, Ch.V.; Jain, R.K.; Rama Rao, J.; Ernst, J.; Machner, H.

    1996-01-01

    The angular distribution of continuous particle spectra in pre-equilibrium reactions is still an unsolved problem, particularly so at forward angles. In the present work, the angular distributions of alpha particles emitted in (α, α',x) reactions in the target elements gold and rhodium have been studied in detail. Alpha particle beams of energy 60 MeV from the Variable Energy Cyclotron of Calcutta were used in these experiments. The theoretical calculations were done using an extended exciton model of Kalbach incorporated into the Computer Code PRECO-D2. The formalism used in the exciton model was modified to include division of pre equilibrium cross section into multi-step direct (MSD) and multi-step compound (MSC) components. These MSD and MSC cross sections were used to calculate the angular distributions in terms of Legendre polynomials whose coefficients are given by simple phenomenological relations. Even with a reasonable set of parameters, the agreement between theory and experiment was far from satisfactory at forward angles. Similar conclusion was also drawn in the case of continuous particle spectra of deuterons in (d, d'x) reactions at 25 MeV in various targets. (author). 10 refs., 2 figs

  1. Iterative reconstruction of volumetric particle distribution

    International Nuclear Information System (INIS)

    Wieneke, Bernhard

    2013-01-01

    For tracking the motion of illuminated particles in space and time several volumetric flow measurement techniques are available like 3D-particle tracking velocimetry (3D-PTV) recording images from typically three to four viewing directions. For higher seeding densities and the same experimental setup, tomographic PIV (Tomo-PIV) reconstructs voxel intensities using an iterative tomographic reconstruction algorithm (e.g. multiplicative algebraic reconstruction technique, MART) followed by cross-correlation of sub-volumes computing instantaneous 3D flow fields on a regular grid. A novel hybrid algorithm is proposed here that similar to MART iteratively reconstructs 3D-particle locations by comparing the recorded images with the projections calculated from the particle distribution in the volume. But like 3D-PTV, particles are represented by 3D-positions instead of voxel-based intensity blobs as in MART. Detailed knowledge of the optical transfer function and the particle image shape is mandatory, which may differ for different positions in the volume and for each camera. Using synthetic data it is shown that this method is capable of reconstructing densely seeded flows up to about 0.05 ppp with similar accuracy as Tomo-PIV. Finally the method is validated with experimental data. (paper)

  2. Ulcerative Keratitis: incidence, seasonal distribution and ...

    African Journals Online (AJOL)

    Commonest predisposing risk factor was non- surgical trauma 43(70.5%) followed by use of harmful Traditional Eye Medicine (TEM) 27(44.3%). The seasonal distribution of corneal ulcer was highest in month June 11(18.0%). Complications from the ulcers included central leucoma 19 (31.2%) and panophthalmitis 6 (9.9%).

  3. Particle size distribution control of Pt particles used for particle gun

    Science.gov (United States)

    Ichiji, M.; Akiba, H.; Nagao, H.; Hirasawa, I.

    2017-07-01

    The purpose of this study is particle size distribution (PSD) control of submicron sized Pt particles used for particle gun. In this report, simple reaction crystallization is conducted by mixing H2PtCl6 and ascorbic acid. Without the additive, obtained Pt particles have broad PSD and reproducibility of experiment is low. With seeding, Pt particles have narrow PSD and reproducibility improved. Additionally, mean particle diameter of 100-700 nm is controlled by changing seeding amount. Obtained particles are successfully characterized as Pt by XRD results. Moreover, XRD spectra indicate that obtained particles are polycrystals. These experimental results suggest that seeding consumed nucleation, as most nuclei attached on the seed surface. This mechanism virtually restricted nucleation to have narrow PSD can be obtained.

  4. Vibro-spring particle size distribution analyser

    International Nuclear Information System (INIS)

    Patel, Ketan Shantilal

    2002-01-01

    This thesis describes the design and development of an automated pre-production particle size distribution analyser for particles in the 20 - 2000 μm size range. This work is follow up to the vibro-spring particle sizer reported by Shaeri. In its most basic form, the instrument comprises a horizontally held closed coil helical spring that is partly filled with the test powder and sinusoidally vibrated in the transverse direction. Particle size distribution data are obtained by stretching the spring to known lengths and measuring the mass of the powder discharged from the spring's coils. The size of the particles on the other hand is determined from the spring 'intercoil' distance. The instrument developed by Shaeri had limited use due to its inability to measure sample mass directly. For the device reported here, modifications are made to the original configurations to establish means of direct sample mass measurement. The feasibility of techniques for measuring the mass of powder retained within the spring are investigated in detail. Initially, the measurement of mass is executed in-situ from the vibration characteristics based on the spring's first harmonic resonant frequency. This method is often erratic and unreliable due to the particle-particle-spring wall interactions and the spring bending. An much more successful alternative is found from a more complicated arrangement in which the spring forms part of a stiff cantilever system pivoted along its main axis. Here, the sample mass is determined in the 'static mode' by monitoring the cantilever beam's deflection following the wanton termination of vibration. The system performance has been optimised through the variations of the mechanical design of the key components and the operating procedure as well as taking into account the effect of changes in the ambient temperature on the system's response. The thesis also describes the design and development of the ancillary mechanisms. These include the pneumatic

  5. Incidence Rate and Distribution of Common Cancers among Iranian Children

    Directory of Open Access Journals (Sweden)

    Salman Khazaei

    2017-01-01

    Full Text Available Background: Geographic differences in the incidence of cancers may suggest unique genetic or environmental exposures that impact the risk of acquiring cancer. This research aims to determine the incidence rate and geographical distribution of common cancers among Iranian children. Methods: In this ecological study, we extracted data that pertained to the incidence rate of common cancers among children from reports by the National Registry of Cancer and Disease Control and Prevention in 2008. A map of the cancer incidence rates was designed by using geographic information system. Results:The most common cancer sites among children were the hematology system, brain and central nervous system, and lymph nodes. The central provinces had the lowest cancer incidences. Conclusion: The considerable variation in incidence of childhood cancers in Iran suggests a possible potential environmental risk factor or genetic background related to this increased risk among children.

  6. Remote Laser Diffraction Particle Size Distribution Analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Batcheller, Thomas Aquinas; Huestis, Gary Michael; Bolton, Steven Michael

    2001-03-01

    In support of a radioactive slurry sampling and physical characterization task, an “off-the-shelf” laser diffraction (classical light scattering) particle size analyzer was utilized for remote particle size distribution (PSD) analysis. Spent nuclear fuel was previously reprocessed at the Idaho Nuclear Technology and Engineering Center (INTEC—formerly recognized as the Idaho Chemical Processing Plant) which is on DOE’s INEEL site. The acidic, radioactive aqueous raffinate streams from these processes were transferred to 300,000 gallon stainless steel storage vessels located in the INTEC Tank Farm area. Due to the transfer piping configuration in these vessels, complete removal of the liquid can not be achieved. Consequently, a “heel” slurry remains at the bottom of an “emptied” vessel. Particle size distribution characterization of the settled solids in this remaining heel slurry, as well as suspended solids in the tank liquid, is the goal of this remote PSD analyzer task. A Horiba Instruments Inc. Model LA-300 PSD analyzer, which has a 0.1 to 600 micron measurement range, was modified for remote application in a “hot cell” (gamma radiation) environment. This technology provides rapid and simple PSD analysis, especially down in the fine and microscopic particle size regime. Particle size analysis of these radioactive slurries down in this smaller range was not previously achievable—making this technology far superior than the traditional methods used. Successful acquisition of this data, in conjunction with other characterization analyses, provides important information that can be used in the myriad of potential radioactive waste management alternatives.

  7. Spatial Distribution of Black Bear Incident Reports in Michigan.

    Directory of Open Access Journals (Sweden)

    Jamie E McFadden-Hiller

    Full Text Available Interactions between humans and carnivores have existed for centuries due to competition for food and space. American black bears are increasing in abundance and populations are expanding geographically in many portions of its range, including areas that are also increasing in human density, often resulting in associated increases in human-bear conflict (hereafter, bear incidents. We used public reports of bear incidents in Michigan, USA, from 2003-2011 to assess the relative contributions of ecological and anthropogenic variables in explaining the spatial distribution of bear incidents and estimated the potential risk of bear incidents. We used weighted Normalized Difference Vegetation Index mean as an index of primary productivity, region (i.e., Upper Peninsula or Lower Peninsula, primary and secondary road densities, and percentage land cover type within 6.5-km2 circular buffers around bear incidents and random points. We developed 22 a priori models and used generalized linear models and Akaike's Information Criterion (AIC to rank models. The global model was the best compromise between model complexity and model fit (w = 0.99, with a ΔAIC 8.99 units from the second best performing model. We found that as deciduous forest cover increased, the probability of bear incident occurrence increased. Among the measured anthropogenic variables, cultivated crops and primary roads were the most important in our AIC-best model and were both positively related to the probability of bear incident occurrence. The spatial distribution of relative bear incident risk varied markedly throughout Michigan. Forest cover fragmented with agriculture and other anthropogenic activities presents an environment that likely facilitates bear incidents. Our map can help wildlife managers identify areas of bear incident occurrence, which in turn can be used to help develop strategies aimed at reducing incidents. Researchers and wildlife managers can use similar mapping

  8. Spatial Distribution of Black Bear Incident Reports in Michigan.

    Science.gov (United States)

    McFadden-Hiller, Jamie E; Beyer, Dean E; Belant, Jerrold L

    2016-01-01

    Interactions between humans and carnivores have existed for centuries due to competition for food and space. American black bears are increasing in abundance and populations are expanding geographically in many portions of its range, including areas that are also increasing in human density, often resulting in associated increases in human-bear conflict (hereafter, bear incidents). We used public reports of bear incidents in Michigan, USA, from 2003-2011 to assess the relative contributions of ecological and anthropogenic variables in explaining the spatial distribution of bear incidents and estimated the potential risk of bear incidents. We used weighted Normalized Difference Vegetation Index mean as an index of primary productivity, region (i.e., Upper Peninsula or Lower Peninsula), primary and secondary road densities, and percentage land cover type within 6.5-km2 circular buffers around bear incidents and random points. We developed 22 a priori models and used generalized linear models and Akaike's Information Criterion (AIC) to rank models. The global model was the best compromise between model complexity and model fit (w = 0.99), with a ΔAIC 8.99 units from the second best performing model. We found that as deciduous forest cover increased, the probability of bear incident occurrence increased. Among the measured anthropogenic variables, cultivated crops and primary roads were the most important in our AIC-best model and were both positively related to the probability of bear incident occurrence. The spatial distribution of relative bear incident risk varied markedly throughout Michigan. Forest cover fragmented with agriculture and other anthropogenic activities presents an environment that likely facilitates bear incidents. Our map can help wildlife managers identify areas of bear incident occurrence, which in turn can be used to help develop strategies aimed at reducing incidents. Researchers and wildlife managers can use similar mapping techniques to

  9. Concentration and size distribution of particles in abstracted groundwater.

    Science.gov (United States)

    van Beek, C G E M; de Zwart, A H; Balemans, M; Kooiman, J W; van Rosmalen, C; Timmer, H; Vandersluys, J; Stuyfzand, P J

    2010-02-01

    Particle number concentrations have been counted and particle size distributions calculated in groundwater derived by abstraction wells. Both concentration and size distribution are governed by the discharge rate: the higher this rate the higher the concentration and the higher the proportion of larger particles. However, the particle concentration in groundwater derived from abstraction wells, with high groundwater flow velocities, is much lower than in groundwater from monitor wells, with minimal flow velocities. This inconsistency points to exhaustion of the particle supply in the aquifer around wells due to groundwater abstraction for many years. The particle size distribution can be described with the help of a power law or Pareto distribution. Comparing the measured particle size distribution with the Pareto distribution shows that particles with a diameter >7 microm are under-represented. As the particle size distribution is dependent on the flow velocity, so is the value of the "Pareto" slope beta. (c) 2009 Elsevier Ltd. All rights reserved.

  10. Measurements of double differential charged particle emission cross sections by incident D-T neutrons

    International Nuclear Information System (INIS)

    Kondoh, Takehiro; Takahashi, Akito; Nishizawa, Hiroshi.

    1995-01-01

    Double differential cross sections for nat Ni(n,xα) and nat Cu(n,xα) reactions with 14.1 MeV incident neutrons were measured based on the E-TOF two dimensional analysis. Measured data were compared with the other experimental data reported by N. Ito et al. and by S.M. Grimes et al, evaluated data of the ENDF/B-VI and SINCROS-II calculation. Concerning the nat Ni(n,xα) reaction, it was observed in this experiment that the angular distributions of α-particle emission showed a forward-peaked tendency except for the low energy region. (author)

  11. The distributional incidence of the gasoline tax in Chile

    International Nuclear Information System (INIS)

    Agostini, Claudio A.; Jiménez, Johanna

    2015-01-01

    This paper analyzes the distributional incidence of the excise tax on gasoline in Chile using Household Budget Surveys. The incidence is calculated with respect to both income and expenditure distributions in order to consider the potential differences between transitory and permanent income. The Suits Index is estimated as a measure of the degree of progressivity of the tax, and confidence intervals are calculated using a bootstrap methodology to statistically compare changes in the incidence given changes in the tax. The results show that the tax, contrary to the evidence for several developed countries, is slightly or moderately progressive, with a lower degree of progressivity observed in the calculations based on income than those based on expenditure. The simulation of the 25% reduction in the tax rate implemented in 2008 shows that, in terms of incidence, its effect is to reduce the progressivity of the gasoline tax, which is the opposite of what was sought by the government with this policy. -- Highlights: •Gasoline tax is an optimal tax and is a significant instrument of climate policy. •Despite its benefits, it faces political economy challenges in its implementation. •In the public discussion in developing countries the tax is considered regressive. •The estimation of the distributional incidence shows that it is slightly progressive. •Increases in gasoline taxes can reduce both negative externalities and inequality

  12. Nongyrotropic particle distributions in space plasmas

    Directory of Open Access Journals (Sweden)

    U. Motschmann

    Full Text Available In nonstationary, strong inhomogeneous or open plasmas particle orbits are rather complicated. If the nonstationary time scale is smaller than the gyration period, if the inhomogeneity scale is smaller than the gyration radius, i.e. at magnetic plasma boundaries, or if the plasma has sources and sinks in phase space, then nongyrotropic distribution functions occur. The stability of such plasma configurations is studied in the framework of linear dispersion theory. In an open plasma nongyrotropy drives unstable waves parallel and perpendicular to the background magnetic field, whereas in the gyrotropic limit the plasma is stable. In nonstationary plasmas nongyrotropy drives perpendicular unstable waves only. Temporal modulation couples a seed mode with its side lobes and thus it renders unstable wave growth more difficult. As an example of an inhomogeneous plasma a magnetic halfspace is discussed. In a layer with thickness of the thermal proton gyroradius a nongyrotropic distribution is formed which may excite unstable parallel and perpendicular propagating waves.

    Key words. Interplanetary physics (plasma waves and turbulence · Ionosphere (plasma waves and instabilities · Magnetospheric physics (plasma waves and instabilities

  13. Distribution of lead in single atmospheric particles

    Science.gov (United States)

    Murphy, D. M.; Hudson, P. K.; Cziczo, D. J.; Gallavardin, S.; Froyd, K. D.; Johnston, M. V.; Middlebrook, A. M.; Reinard, M. S.; Thomson, D. S.; Thornberry, T.; Wexler, A. S.

    2007-06-01

    Three independent single particle mass spectrometers measured Pb in individual aerosol particles. These data provide unprecedented sensitivity and statistical significance for the measurement of Pb in single particles. This paper explores the reasons for the frequency of Pb in fine particles now that most gasoline is unleaded. Trace amounts of Pb were found in 5 to 25% of 250 to 3000 nm diameter particles sampled by both aircraft and surface instruments in the eastern and western United States. Over 5% of particles at a mountain site in Switzerland contained Pb. Particles smaller than 100 nm with high Pb content were also observed by an instrument that was only operated in urban areas. Lead was found on all types of particles, including Pb present on biomass burning particles from remote fires. Less common particles with high Pb contents contributed a majority of the total amount of Pb. Single particles with high Pb content often also contained alkali metals, Zn, Cu, Sn, As, and Sb. The association of Pb with Zn and other metals is also found in IMPROVE network filter data from surface sites. Sources of airborne Pb in the United States are reviewed for consistency with these data. The frequent appearance of trace Pb is consistent with widespread emissions of fine Pb particles from combustion sources followed by coagulation with larger particles during long-range transport. Industrial sources that directly emit Pb-rich particles also contribute to the observations. Clean regions of the western United States show some transport of Pb from Asia but most Pb over the United States comes from North American sources. Resuspension of Pb from soil contaminated by the years of leaded gasoline was not directly apparent.

  14. Multiplicity distributions of shower particles and target fragments in ...

    Indian Academy of Sciences (India)

    Em (emul- sion) collisions at 3 A GeV/c are experimentally studied. In the framework of the multisource thermal model, the multicomponent Erlang distribution is used to describe the experimental mul- tiplicity distributions of shower particles, ...

  15. Multiplicity distributions of shower particles and target fragments in 7 ...

    Indian Academy of Sciences (India)

    emulsion) collisions at 3 A GeV/c are experimentally studied. In the framework of the multisource thermal model, the multicomponent Erlang distribution is used to describe the experimental multiplicity distributions of shower particles, grey fragments ...

  16. Concentration and size distribution of particles in abstracted groundwater

    NARCIS (Netherlands)

    Van Beek, C.G.E.M.; de Zwart, A.H.; Balemans, M.; Kooiman, J.W.; van Rosmalen, C.; Timmer, H.; Vandersluys, J.; Stuijfzand, P.J.

    2010-01-01

    Particle number concentrations have been counted and particle size distributions calculated in groundwater derived by abstraction wells. Both concentration and size distribution are governed by the discharge rate: the higher this rate the higher the concentration and the higher the proportion of

  17. Improved mathematical models for particle-size distribution data ...

    African Journals Online (AJOL)

    Prior studies have suggested that particle-size distribution data of soils is central and helpful in this regard. This study proposes two improved mathematical models to describe and represent the varied particle-size distribution (PSD) data for tropically weathered residual (TWR) soils. The theoretical analysis and the ...

  18. Dust particle charge distribution in a stratified glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Sukhinin, Gennady I [Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Lavrentyev Ave., 1, Novosibirsk 630090 (Russian Federation); Fedoseev, Alexander V [Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Lavrentyev Ave., 1, Novosibirsk 630090 (Russian Federation); Ramazanov, Tlekkabul S [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan); Dzhumagulova, Karlygash N [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan); Amangaliyeva, Rauan Zh [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan)

    2007-12-21

    The influence of a highly pronounced non-equilibrium characteristic of the electron energy distribution function in a stratified dc glow discharge on the process of dust particle charging in a complex plasma is taken into account for the first time. The calculated particle charge spatial distribution is essentially non-homogeneous and it can explain the vortex motion of particles at the periphery of a dusty cloud obtained in experiments.

  19. Dependence of extinction cross-section on incident polarization state and particle orientation

    International Nuclear Information System (INIS)

    Yang Ping; Wendisch, Manfred; Bi Lei; Kattawar, George; Mishchenko, Michael; Hu, Yongxiang

    2011-01-01

    This note reports on the effects of the polarization state of an incident quasi-monochromatic parallel beam of radiation and the orientation of a hexagonal ice particle with respect to the incident direction on the extinction process. When the incident beam is aligned with the six-fold rotational symmetry axis, the extinction is independent of the polarization state of the incident light. For other orientations, the extinction cross-section for linearly polarized light can be either larger or smaller than its counterpart for an unpolarized incident beam. Therefore, the attenuation of a quasi-monochromatic radiation beam by an ice cloud depends on the polarization state of the beam if ice crystals within the cloud are not randomly oriented. Furthermore, a case study of the extinction of light by a quartz particle is also presented to illustrate the dependence of the extinction cross-section on the polarization state of the incident light.

  20. Incidence and distribution of pediatric sport-related injuries.

    Science.gov (United States)

    Caine, Dennis; Caine, Caroline; Maffulli, Nicola

    2006-11-01

    To provide a critical review of the available literature on the descriptive epidemiology of pediatric sport-related injuries. MEDLINE (1966 to 2006) and SPORTDiscus (1975 to 2006) were searched to identify potentially relevant articles. A combination of medical subject headings and text words was used (epidemiology, children, adolescents, athletic injuries, sports, injury, and injuries). Additional references from the bibliographies of retrieved articles were also reviewed. Published research reports on the incidence and distribution of injury in children's and youth sports. Specific emphasis was placed on reviewing original studies, which report incidence rates (rate of injuries per unit athlete time). Forty-nine studies were selected for this review. Data summarized include incidence of injury relative to who is affected by injury (sport, participation level, gender, and player position), where injury occurs (anatomical and environmental location), when injury occurs (injury onset and chronometry), and injury outcome (injury type, time loss, clinical outcome, and economic cost). There is little epidemiological data on injuries for some pediatric sports. Many of the studies retrieved were characterized by methodological short-comings and study differences that limit interpretation and comparison of findings across studies. Notwithstanding, the studies reviewed are encouraging and injury patterns that should be studied further with more rigorous study designs to confirm original findings and to probe causes of injury and the effectiveness of preventive measures. Incidence and severity of injury are high in some child and youth sports. This review will assist in targeting the relevant groups and in designing future research on the epidemiology of pediatric sports injuries. Well-designed descriptive and analytical studies are needed to identify the public health impact of pediatric sport injury.

  1. Transverse momentum distributions and particle correlations from EMU05

    International Nuclear Information System (INIS)

    Takahashi, Y.; Chan, C.H.; Duthie, J.G.

    1988-01-01

    Transverse momentum distributions and multi-particle correlations of charged particles in 200 GeV/AMU heavy-ion collisions are studied with the Magnetic-Interferometric-Emulsion-Chamber (MAGIC) for central collision events in 16 O + Pb and 32 S + Pb interactions. The P/sub T/ distribution of negative-charged particles below 1 GeV/c fits a single exponential, while that of positive particles contains additional contributions of both high and low-P/sub T/ particles. The like-sign, two particle correlations indicate HBT interferences, while that of the unlike-sign pairs possibly suggests other components. The apparent, multi-particle, charge-sign clustering is studied with the run-test and with Monte Carlo simulations. Some of the data are consistent with chance coincidence and the HBT interference. 6 refs., 6 figs

  2. Dust Particle Size Distributions during Spring in Yinchuan, China

    Directory of Open Access Journals (Sweden)

    Jiangfeng Shao

    2016-01-01

    Full Text Available Dust particle size distributions in Yinchuan, China, were measured during March and April 2014, using APS-3321 sampler. The distributions were measured under different dust conditions (background, floating dust, blowing dust, and dust storm and statistical analyses were performed. The results showed that, under different dust conditions, the instantaneous number concentrations of dust particles differed widely. For example, during blowing sand and dust storm conditions, instantaneous dust particles concentrations varied substantially, while, under floating dust conditions, concentration differences were relatively small. The average dust particles size distributions were unimodal under all dust conditions, but the average surface area and mass size distributions were all bimodal. These distributions had peaks in different locations under different dust conditions. Under different dust conditions, wind speed and humidity were very important factors for particles size distributions. With increasing wind speed and decreasing humidity, fine particles were dominant in the atmosphere and the number and mass distributions of the coarse particles were indicative of long-range transport from surrounding deserts. Different dust conditions had different influences on PM1, PM2.5, and PM10 concentrations.

  3. Theoretical method for determining particle distribution functions of classical systems

    International Nuclear Information System (INIS)

    Johnson, E.

    1980-01-01

    An equation which involves the triplet distribution function and the three-particle direct correlation function is obtained. This equation was derived using an analogue of the Ornstein--Zernike equation. The new equation is used to develop a variational method for obtaining the triplet distribution function of uniform one-component atomic fluids from the pair distribution function. The variational method may be used with the first and second equations in the YBG hierarchy to obtain pair and triplet distribution functions. It should be easy to generalize the results to the n-particle distribution function

  4. Effects of Initial Particle Distribution on an Energetic Dispersal of Particles

    Science.gov (United States)

    Rollin, Bertrand; Ouellet, Frederick; Koneru, Rahul; Garno, Joshua; Durant, Bradford

    2017-11-01

    Accurate predictions of the late time solid particle cloud distribution ensuing an explosive dispersal of particles is an extremely challenging problem for compressible multiphase flow simulations. The source of this difficulty is twofold: (i) The complex sequence of events taking place. Indeed, as the blast wave crosses the surrounding layer of particles, compaction occurs shortly before particles disperse radially at high speed. Then, during the dispersion phase, complex multiphase interactions occurs between particles and detonation products. (ii) Precise characterization of the explosive and particle distribution is virtually impossible. In this numerical experiment, we focus on the sensitivity of late time particle cloud distributions relative to carefully designed initial distributions, assuming the explosive is well described. Using point particle simulations, we study the case of a bed of glass particles surrounding an explosive. Constraining our simulations to relatively low initial volume fractions to prevent reaching of the close packing limit, we seek to describe qualitatively and quantitatively the late time dependency of a solid particle cloud on its distribution before the energy release of an explosive. This work was supported by the U.S. DoE, NNSA, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, under Contract No. DE-NA0002378.

  5. Distributed SLAM Using Improved Particle Filter for Mobile Robot Localization

    Directory of Open Access Journals (Sweden)

    Fujun Pei

    2014-01-01

    Full Text Available The distributed SLAM system has a similar estimation performance and requires only one-fifth of the computation time compared with centralized particle filter. However, particle impoverishment is inevitably because of the random particles prediction and resampling applied in generic particle filter, especially in SLAM problem that involves a large number of dimensions. In this paper, particle filter use in distributed SLAM was improved in two aspects. First, we improved the important function of the local filters in particle filter. The adaptive values were used to replace a set of constants in the computational process of importance function, which improved the robustness of the particle filter. Second, an information fusion method was proposed by mixing the innovation method and the number of effective particles method, which combined the advantages of these two methods. And this paper extends the previously known convergence results for particle filter to prove that improved particle filter converges to the optimal filter in mean square as the number of particles goes to infinity. The experiment results show that the proposed algorithm improved the virtue of the DPF-SLAM system in isolate faults and enabled the system to have a better tolerance and robustness.

  6. Particle size and shape distributions of hammer milled pine

    Energy Technology Data Exchange (ETDEWEB)

    Westover, Tyler Lott [Idaho National Lab. (INL), Idaho Falls, ID (United States); Matthews, Austin Colter [Idaho National Lab. (INL), Idaho Falls, ID (United States); Williams, Christopher Luke [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ryan, John Chadron Benjamin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-04-01

    Particle size and shape distributions impact particle heating rates and diffusion of volatized gases out of particles during fast pyrolysis conversion, and consequently must be modeled accurately in order for computational pyrolysis models to produce reliable results for bulk solid materials. For this milestone, lodge pole pine chips were ground using a Thomas-Wiley #4 mill using two screen sizes in order to produce two representative materials that are suitable for fast pyrolysis. For the first material, a 6 mm screen was employed in the mill and for the second material, a 3 mm screen was employed in the mill. Both materials were subjected to RoTap sieve analysis, and the distributions of the particle sizes and shapes were determined using digital image analysis. The results of the physical analysis will be fed into computational pyrolysis simulations to create models of materials with realistic particle size and shape distributions. This milestone was met on schedule.

  7. Environmental DNA particle size distribution from Brook Trout (Salvelinus fontinalis)

    Science.gov (United States)

    Taylor M. Wilcox; Kevin S. McKelvey; Michael K. Young; Winsor H. Lowe; Michael K. Schwartz

    2015-01-01

    Environmental DNA (eDNA) sampling has become a widespread approach for detecting aquatic animals with high potential for improving conservation biology. However, little research has been done to determine the size of particles targeted by eDNA surveys. In this study, we conduct particle distribution analysis of eDNA from a captive Brook Trout (Salvelinus fontinalis) in...

  8. Particle Distribution in a Fixed Bed Down Draft Wood Gasifier

    DEFF Research Database (Denmark)

    Hindsgaul, Claus

    2005-01-01

    Char particle samples were collected from six distances above the grate in a fixed bed of a down draft biomass gasifier. Each sample was separated into twelve size fractions by screening through standard sieves in order to determine the local particle size distribution. The ash contents of each...

  9. Dust Particle Size Distributions during Spring in Yinchuan, China

    OpenAIRE

    Jiangfeng Shao; Jiandong Mao

    2016-01-01

    Dust particle size distributions in Yinchuan, China, were measured during March and April 2014, using APS-3321 sampler. The distributions were measured under different dust conditions (background, floating dust, blowing dust, and dust storm) and statistical analyses were performed. The results showed that, under different dust conditions, the instantaneous number concentrations of dust particles differed widely. For example, during blowing sand and dust storm conditions, instantaneous dust pa...

  10. The Particle Distribution in Liquid Metal with Ceramic Particles Mould Filling Process

    Science.gov (United States)

    Dong, Qi; Xing, Shu-ming

    2017-09-01

    Adding ceramic particles in the plate hammer is an effective method to increase the wear resistance of the hammer. The liquid phase method is based on the “with the flow of mixed liquid forging composite preparation of ZTA ceramic particle reinforced high chromium cast iron hammer. Preparation method for this system is using CFD simulation analysis the particles distribution of flow mixing and filling process. Taking the 30% volume fraction of ZTA ceramic composite of high chromium cast iron hammer as example, by changing the speed of liquid metal viscosity to control and make reasonable predictions of particles distribution before solidification.

  11. Inversion of particle size distribution by spectral extinction technique using the attractive and repulsive particle swarm optimization algorithm

    Directory of Open Access Journals (Sweden)

    Qi Hong

    2015-01-01

    Full Text Available The particle size distribution (PSD plays an important role in environmental pollution detection and human health protection, such as fog, haze and soot. In this study, the Attractive and Repulsive Particle Swarm Optimization (ARPSO algorithm and the basic PSO were applied to retrieve the PSD. The spectral extinction technique coupled with the Anomalous Diffraction Approximation (ADA and the Lambert-Beer Law were employed to investigate the retrieval of the PSD. Three commonly used monomodal PSDs, i.e. the Rosin-Rammer (R-R distribution, the normal (N-N distribution, the logarithmic normal (L-N distribution were studied in the dependent model. Then, an optimal wavelengths selection algorithm was proposed. To study the accuracy and robustness of the inverse results, some characteristic parameters were employed. The research revealed that the ARPSO showed more accurate and faster convergence rate than the basic PSO, even with random measurement error. Moreover, the investigation also demonstrated that the inverse results of four incident laser wavelengths showed more accurate and robust than those of two wavelengths. The research also found that if increasing the interval of the selected incident laser wavelengths, inverse results would show more accurate, even in the presence of random error.

  12. Higher order correlations in computed particle distributions

    International Nuclear Information System (INIS)

    Hanerfeld, H.; Herrmannsfeldt, W.; Miller, R.H.

    1989-03-01

    The rms emittances calculated for beam distributions using computer simulations are frequently dominated by higher order aberrations. Thus there are substantial open areas in the phase space plots. It has long been observed that the rms emittance is not an invariant to beam manipulations. The usual emittance calculation removes the correlation between transverse displacement and transverse momentum. In this paper, we explore the possibility of defining higher order correlations that can be removed from the distribution to result in a lower limit to the realizable emittance. The intent is that by inserting the correct combinations of linear lenses at the proper position, the beam may recombine in a way that cancels the effects of some higher order forces. An example might be the non-linear transverse space charge forces which cause a beam to spread. If the beam is then refocused so that the same non-linear forces reverse the inward velocities, the resulting phase space distribution may reasonably approximate the original distribution. The approach to finding the location and strength of the proper lens to optimize the transported beam is based on work by Bruce Carlsten of Los Alamos National Laboratory. 11 refs., 4 figs

  13. Validity of the negative binomial distribution in particle production

    International Nuclear Information System (INIS)

    Cugnon, J.; Harouna, O.

    1987-01-01

    Some aspects of the clan picture for particle production in nuclear and in high-energy processes are examined. In particular, it is shown that the requirement of having logarithmic distribution for the number of particles within a clan in order to generate a negative binomial should not be taken strictly. Large departures are allowed without distorting too much the negative binomial. The question of the undetected particles is also studied. It is shown that, under reasonable circumstances, the latter do not affect the negative binomial character of the multiplicity distribution

  14. Distribution Of Natural Radioactivity On Soil Size Particles

    International Nuclear Information System (INIS)

    Tran Van Luyen; Trinh Hoai Vinh; Thai Khac Dinh

    2008-01-01

    This report presents a distribution of natural radioactivity on different soil size particles, taken from one soil profile. On the results shows a range from 52% to 66% of natural radioisotopes such as 238 U, 232 Th, 226 Ra and 40 K concentrated on the soil particles below 40 micrometers in diameter size. The remained of natural radioisotopes were distributed on a soil particles with higher diameter size. The study is available for soil sample collected to natural radioactive analyze by gamma and alpha spectrometer methods. (author)

  15. Gaussian theory for spatially distributed self-propelled particles

    Science.gov (United States)

    Seyed-Allaei, Hamid; Schimansky-Geier, Lutz; Ejtehadi, Mohammad Reza

    2016-12-01

    Obtaining a reduced description with particle and momentum flux densities outgoing from the microscopic equations of motion of the particles requires approximations. The usual method, we refer to as truncation method, is to zero Fourier modes of the orientation distribution starting from a given number. Here we propose another method to derive continuum equations for interacting self-propelled particles. The derivation is based on a Gaussian approximation (GA) of the distribution of the direction of particles. First, by means of simulation of the microscopic model, we justify that the distribution of individual directions fits well to a wrapped Gaussian distribution. Second, we numerically integrate the continuum equations derived in the GA in order to compare with results of simulations. We obtain that the global polarization in the GA exhibits a hysteresis in dependence on the noise intensity. It shows qualitatively the same behavior as we find in particles simulations. Moreover, both global polarizations agree perfectly for low noise intensities. The spatiotemporal structures of the GA are also in agreement with simulations. We conclude that the GA shows qualitative agreement for a wide range of noise intensities. In particular, for low noise intensities the agreement with simulations is better as other approximations, making the GA to an acceptable candidates of describing spatially distributed self-propelled particles.

  16. Particle size distribution: A key factor in estimating powder dustiness.

    Science.gov (United States)

    López Lilao, Ana; Sanfélix Forner, Vicenta; Mallol Gasch, Gustavo; Monfort Gimeno, Eliseo

    2017-12-01

    A wide variety of raw materials, involving more than 20 samples of quartzes, feldspars, nephelines, carbonates, dolomites, sands, zircons, and alumina, were selected and characterised. Dustiness, i.e., a materials' tendency to generate dust on handling, was determined using the continuous drop method. These raw materials were selected to encompass a wide range of particle sizes (1.6-294 µm) and true densities (2650-4680 kg/m 3 ). The dustiness of the raw materials, i.e., their tendency to generate dust on handling, was determined using the continuous drop method. The influence of some key material parameters (particle size distribution, flowability, and specific surface area) on dustiness was assessed. In this regard, dustiness was found to be significantly affected by particle size distribution. Data analysis enabled development of a model for predicting the dustiness of the studied materials, assuming that dustiness depended on the particle fraction susceptible to emission and on the bulk material's susceptibility to release these particles. On the one hand, the developed model allows the dustiness mechanisms to be better understood. In this regard, it may be noted that relative emission increased with mean particle size. However, this did not necessarily imply that dustiness did, because dustiness also depended on the fraction of particles susceptible to be emitted. On the other hand, the developed model enables dustiness to be estimated using just the particle size distribution data. The quality of the fits was quite good and the fact that only particle size distribution data are needed facilitates industrial application, since these data are usually known by raw materials managers, thus making additional tests unnecessary. This model may therefore be deemed a key tool in drawing up efficient preventive and/or corrective measures to reduce dust emissions during bulk powder processing, both inside and outside industrial facilities. It is recommended, however

  17. Saharan Dust Particle Size And Concentration Distribution In Central Ghana

    Science.gov (United States)

    Sunnu, A. K.

    2010-12-01

    A.K. Sunnu*, G. M. Afeti* and F. Resch+ *Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology (KNUST) Kumasi, Ghana. E-mail: albertsunnu@yahoo.com +Laboratoire Lepi, ISITV-Université du Sud Toulon-Var, 83162 La Valette cedex, France E-mail: resch@univ-tln.fr Keywords: Atmospheric aerosol; Saharan dust; Particle size distributions; Particle concentrations. Abstract The Saharan dust that is transported and deposited over many countries in the West African atmospheric environment (5°N), every year, during the months of November to March, known locally as the Harmattan season, have been studied over a 13-year period, between 1996 and 2009, using a location at Kumasi in central Ghana (6° 40'N, 1° 34'W) as the reference geographical point. The suspended Saharan dust particles were sampled by an optical particle counter, and the particle size distributions and concentrations were analysed. The counter gives the total dust loads as number of particles per unit volume of air. The optical particle counter used did not discriminate the smoke fractions (due to spontaneous bush fires during the dry season) from the Saharan dust. Within the particle size range measured (0.5 μm-25 μm.), the average inter-annual mean particle diameter, number and mass concentrations during the northern winter months of January and February were determined. The average daily number concentrations ranged from 15 particles/cm3 to 63 particles/cm3 with an average of 31 particles/cm3. The average daily mass concentrations ranged from 122 μg/m3 to 1344 μg/m3 with an average of 532 μg/m3. The measured particle concentrations outside the winter period were consistently less than 10 cm-3. The overall dust mean particle diameter, analyzed from the peak representative Harmattan periods over the 13-year period, ranged from 0.89 μm to 2.43 μm with an average of 1.5 μm ± 0.5. The particle size distributions exhibited the typical distribution pattern for

  18. Contact angle distribution of particles at fluid interfaces.

    Science.gov (United States)

    Snoeyink, Craig; Barman, Sourav; Christopher, Gordon F

    2015-01-27

    Recent measurements have implied a distribution of interfacially adsorbed particles' contact angles; however, it has been impossible to measure statistically significant numbers for these contact angles noninvasively in situ. Using a new microscopy method that allows nanometer-scale resolution of particle's 3D positions on an interface, we have measured the contact angles for thousands of latex particles at an oil/water interface. Furthermore, these measurements are dynamic, allowing the observation of the particle contact angle with high temporal resolution, resulting in hundreds of thousands of individual contact angle measurements. The contact angle has been found to fit a normal distribution with a standard deviation of 19.3°, which is much larger than previously recorded. Furthermore, the technique used allows the effect of measurement error, constrained interfacial diffusion, and particle property variation on the contact angle distribution to be individually evaluated. Because of the ability to measure the contact angle noninvasively, the results provide previously unobtainable, unique data on the dynamics and distribution of the adsorbed particles' contact angle.

  19. Modification of Particle Distributions by MHD Instabilities II

    International Nuclear Information System (INIS)

    White, Roscoe B.

    2011-01-01

    The modification of particle distributions by low amplitude magnetohydrodynamic modes is an important topic for magnetically confined plasmas. Low amplitude modes are known to be capable of producing significant modification of injected neutral beam profiles, and the same can be expected in burning plasmas for the alpha particle distributions. Flattening of a distribution in an island due to phase mixing and portions of phase space becoming stochastic lead to modification of the particle distribution, a process extremely rapid in the time scale of an experiment but still very long compared to the time scale of guiding center simulations. Large amplitude modes can cause profile avalanche and particle loss. Thus it is very valuable to be able to predict the temporal evolution of a particle distribution produced by a given spectrum of magnetohydrodynamic modes. In this paper we further develop and investigate the use of a new method of determining domains of phase space in which good KAM surfaces do not exist and use this method to examine a well documented case of profile modification by instabilities.

  20. Modification of Particle Distributions by MHD Instabilities II

    Energy Technology Data Exchange (ETDEWEB)

    Roscoe B. White

    2011-03-02

    The modification of particle distributions by low amplitude magnetohydrodynamic modes is an important topic for magnetically confined plasmas. Low amplitude modes are known to be capable of producing significant modification of injected neutral beam profiles, and the same can be expected in burning plasmas for the alpha particle distributions. Flattening of a distribution in an island due to phase mixing and portions of phase space becoming stochastic lead to modification of the particle distribution, a process extremely rapid in the time scale of an experiment but still very long compared to the time scale of guiding center simulations. Large amplitude modes can cause profile avalanche and particle loss. Thus it is very valuable to be able to predict the temporal evolution of a particle distribution produced by a given spectrum of magnetohydrodynamic modes. In this paper we further develop and investigate the use of a new method of determining domains of phase space in which good KAM surfaces do not exist and use this method to examine a well documented case of profile modification by instabilities.

  1. Measurement of the electrostatic charge in airborne particles: II - particle charge distribution of different aerosols

    Directory of Open Access Journals (Sweden)

    M. V. Rodrigues

    2006-03-01

    Full Text Available This work gives sequence to the study on the measurement of the electrostatic charges in aerosols. The particle charge classifier developed for this purpose and presented in the previous paper (Marra and Coury, 2000 has been used here to measure the particle charge distribution of a number of different aerosols. The charges acquired by the particles were naturally derived from the aerosol generation procedure itself. Two types of aerosol generators were used: the vibrating orifice generator and turntable Venturi plate generator. In the vibrating orifice generator, mono-dispersed particles were generated by a solution of water/ethanol/methylene blue, while in the rotating plate generator, six different materials were utilized. The results showed no clear dependence between electric charge and particle diameter for the mono-dispersed aerosol. However, for the poly-dispersed aerosols, a linear dependence between particle size and charge could be noticed.

  2. Charged-particle inclusive distributions from hadronic Z0 decays

    International Nuclear Information System (INIS)

    O'Shaughnessy, K.

    1990-05-01

    We have measured inclusive distributions for charged particles in hadronic decays of the Z boson. The variables chosen for study were the mean charged-particle multiplicity (left-angle n ch right-angle), scaled momentum (x), and momenta transverse to the sphericity axes (p perpendicular in and p perpendicular out ). The distributions have been corrected for detector effects and are compared with data from e + e - annihilation at lower energies and with the predictions of several QCD-based models. The data are in reasonable agreement with expectations. 12 refs., 2 figs

  3. Distribution, incidence and severity of viral diseases of yam ...

    African Journals Online (AJOL)

    A survey was conducted in major yam cultivation zones in Côte d'Ivoire in 2009 to determine the incidence, severity of viral diseases, and viruses associated with the infected plants. Incidence and severity of the viral diseases were estimated based on symptoms. Enzyme-linked immunosorbent assay (ELISA) and ...

  4. Distribution, incidence and severity of yam (Dioscorea spp

    African Journals Online (AJOL)

    toualy

    2014-01-15

    Jan 15, 2014 ... incidence, severity of viral diseases, and viruses associated with the infected plants. Incidence and severity of the viral diseases were estimated based on symptoms. Enzyme-linked immunosorbent assay. (ELISA) and polymerase chain reaction (PCR)-based techniques were used for the detection of Yam.

  5. Digital PIV Measurements of Acoustic Particle Displacements in a Normal Incidence Impedance Tube

    Science.gov (United States)

    Humphreys, William M., Jr.; Bartram, Scott M.; Parrott, Tony L.; Jones, Michael G.

    1998-01-01

    Acoustic particle displacements and velocities inside a normal incidence impedance tube have been successfully measured for a variety of pure tone sound fields using Digital Particle Image Velocimetry (DPIV). The DPIV system utilized two 600-mj Nd:YAG lasers to generate a double-pulsed light sheet synchronized with the sound field and used to illuminate a portion of the oscillatory flow inside the tube. A high resolution (1320 x 1035 pixel), 8-bit camera was used to capture double-exposed images of 2.7-micron hollow silicon dioxide tracer particles inside the tube. Classical spatial autocorrelation analysis techniques were used to ascertain the acoustic particle displacements and associated velocities for various sound field intensities and frequencies. The results show that particle displacements spanning a range of 1-60 microns can be measured for incident sound pressure levels of 100-130 dB and for frequencies spanning 500-1000 Hz. The ability to resolve 1 micron particle displacements at sound pressure levels in the 100 dB range allows the use of DPIV systems for measurement of sound fields at much lower sound pressure levels than had been previously possible. Representative impedance tube data as well as an uncertainty analysis for the measurements are presented.

  6. Particle size distributions and the vertical distribution of suspended matter in the upwelling region off Oregon

    Science.gov (United States)

    Kitchen, J. C.

    1977-01-01

    Various methods of presenting and mathematically describing particle size distribution are explained and evaluated. The hyperbolic distribution is found to be the most practical but the more complex characteristic vector analysis is the most sensitive to changes in the shape of the particle size distributions. A method for determining onshore-offshore flow patterns from the distribution of particulates was presented. A numerical model of the vertical structure of two size classes of particles was developed. The results show a close similarity to the observed distributions but overestimate the particle concentration by forty percent. This was attributed to ignoring grazing by zooplankton. Sensivity analyses showed the size preference was most responsive to the maximum specific growth rates and nutrient half saturation constants. The verical structure was highly dependent on the eddy diffusivity followed closely by the growth terms.

  7. Modification of Particle Distributions By MHD Instabilities I

    International Nuclear Information System (INIS)

    White, R.B.

    2010-01-01

    The modification of particle distributions by low amplitude magnetohydrodynamic modes is an important topic for magnetically confined plasmas. Low amplitude modes are known to be capable of producing significant modification of injected neutral beam profiles, and the same can be expected in burning plasmas for the alpha particle distributions. Flattening of a distribution due to phase mixing in an island or due to portions of phase space becoming stochastic is a process extremely rapid on the time scale of an experiment but still very long compared to the time scale of guiding center simulations. Thus it is very valuable to be able to locate significant resonances and to predict the final particle distribution produced by a given spectrum of magnetohydrodynamic modes. In this paper we introduce a new method of determining domains of phase space in which good surfaces do not exist and use this method for quickly determining the final state of the particle distribution without carrying out the full time evolution leading to it.

  8. Change of particle size distribution during Brownian coagulation

    International Nuclear Information System (INIS)

    Lee, K.W.

    1984-01-01

    Change in particle size distribution due to Brownian coagulation in the continuum regime has been stuied analytically. A simple analytic solution for the size distribution of an initially lognormal distribution is obtained based on the assumption that the size distribution during the coagulation process attains or can, at least, be represented by a time dependent lognormal function. The results are found to be in a form that corrects Smoluchowski's solution for both polydispersity and size-dependent kernel. It is further shown that regardless of whether the initial distribution is narrow or broad, the spread of the distribution is characterized by approaching a fixed value of the geometric standard deviation. This result has been compared with the self-preserving distribution obtained by similarity theory. (Author)

  9. Stress distribution in conical sandpiles formed with ellipsoidal particles

    Directory of Open Access Journals (Sweden)

    Liu Sida

    2017-01-01

    Full Text Available The properties of a sandpile such as angle of repose and stress distribution are affected by many variables, among which particle shape is one of the most important ones. In this work, ellipsoids which can represent a large range of shapes varying from disk- to cylinder-type are used. The discrete element method (DEM is employed in order to conduct controlled numerical experiments. The results show that 3D conical sandpiles have similar properties as 2D ones reported in the literature. It demonstrates that particle shape affects the magnitude of the contact force network significantly, with spheres being the smallest. As expected, the pressure distribution underneath sandpiles is featured with a relatively small pressure in the centre, and ellipsoids have a more significant stress dip region than spherical particles.

  10. Preparation of leucite powders with controlled particle size distribution

    Czech Academy of Sciences Publication Activity Database

    Novotná, Martina; Kloužková, A.; Maixner, J.; Šatava, Vladimír

    2005-01-01

    Roč. 49, č. 4 (2005), s. 252-258 ISSN 0862-5468 R&D Projects: GA ČR GA104/03/0031 Institutional research plan: CEZ:AV0Z40320502 Keywords : leucite * preparation * particle size distribution Subject RIV: CA - Inorganic Chemistry Impact factor: 0.463, year: 2005

  11. On the momentum distribution of particles participating in nuclear ...

    Indian Academy of Sciences (India)

    On the momentum distribution of particles participating in nuclear stopping. Mandeep Kaur ... School of Physics and Materials Science, Thapar University, Patiala 147 004, India. Dates. Manuscript received: 23 October 2013; Manuscript revised: 22 March 2014; Accepted: 2 April 2014; Early published: 14 September 2014 ...

  12. Charged particle density distributions in Au+ Au collisions at ...

    Indian Academy of Sciences (India)

    Charged particle pseudorapidity distributions have been measured in Au + Au collisions using the BRAHMS detector at RHIC. The results are presented as a function of the collision centrality and the center of mass energy. They are compared to the predictions of different parton scattering models and the important role of ...

  13. Particle size distribution of selected electronic nicotine delivery system products.

    Science.gov (United States)

    Oldham, Michael J; Zhang, Jingjie; Rusyniak, Mark J; Kane, David B; Gardner, William P

    2018-03-01

    Dosimetry models can be used to predict the dose of inhaled material, but they require several parameters including particle size distribution. The reported particle size distributions for aerosols from electronic nicotine delivery system (ENDS) products vary widely and don't always identify a specific product. A low-flow cascade impactor was used to determine the particle size distribution [mass median aerodynamic diameter (MMAD); geometric standard deviation (GSD)] from 20 different cartridge based ENDS products. To assess losses and vapor phase amount, collection efficiency of the system was measured by comparing the collected mass in the impactor to the difference in ENDS product mass. The levels of nicotine, glycerin, propylene glycol, water, and menthol in the formulations of each product were also measured. Regardless of the ENDS product formulation, the MMAD of all tested products was similar and ranged from 0.9 to 1.2 μm with a GSD ranging from 1.7 to 2.2. There was no consistent pattern of change in the MMAD and GSD as a function of number of puffs (cartridge life). The collection efficiency indicated that 9%-26% of the generated mass was deposited in the collection system or was in the vapor phase. The particle size distribution data are suitable for use in aerosol dosimetry programs. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Multiplicity distributions of shower particles and target fragments in ...

    Indian Academy of Sciences (India)

    Figure 1. Multiplicity distributions of (a) shower particles, (b) grey fragments, (c) black fragments, and (d) heavily ionized fragments produced in 3Li–Em collisions at 3 A GeV/c. The histograms and curves are our experimental data and modelling results respectively. Table 1. Parameter values and the corresponding χ2/dof ...

  15. Estimation of particle size distribution of nanoparticles from electrical ...

    Indian Academy of Sciences (India)

    ... blockade (CB) phenomena of electrical conduction through atiny nanoparticle. Considering the ZnO nanocomposites to be spherical, Coulomb-blockade model of quantum dot isapplied here. The size distribution of particle is estimated from that model and compared with the results obtainedfrom AFM and XRD analyses.

  16. Effects of Particle Size Distribution on Bioremediation of Crude Oil ...

    African Journals Online (AJOL)

    Bioremediation has been proven to be the most effective method of cleaning up oil contaminated soils through the application of nutrients and microorganism. Hence, this research presents the effects of particle size distribution on bioremediation of crude oil polluted sandy soils. Six different soil samples were sieved using ...

  17. Size distribution of airborne particles in animal houses

    NARCIS (Netherlands)

    Lai, T.L.H.; Aarnink, A.J.A.; Cambra-Lopez, M.; Huynh, T.T.T.; Parmentier, H.K.; Groot Koerkamp, P.W.G.

    2011-01-01

    The objective of this study was to determine concentration and size distribution of airborne particles inside and outside animal houses for broilers, broiler breeder (with bedding); layers (floor or aviary housing system); turkeys (with bedding), pigs: fatteners (traditional house, low emission

  18. Charged particle density distributions in Au + Au collisions at ...

    Indian Academy of Sciences (India)

    Charged particle pseudorapidity distributions have been measured in Au + Au collisions using the BRAHMS detector at RHIC. The results are presented as a function of the collision centrality and the center of mass energy. They are compared to the predictions of different parton scattering models and the important role of ...

  19. Study of particle size distribution of environment certified reference material

    Directory of Open Access Journals (Sweden)

    I. E. Vasilyeva

    2015-01-01

    Full Text Available One of the most important stages of the developing certified reference materials (CRM of solid natural samples is to describe a particle size distribution of prepared powders. The particle size distribution affects the degree of material homogeneity and the value representative of the analytical sample mass. The collection of CRMs was being produced at the Vinogradov Institute of Geochemistry SB RAS through a long time span; therefore the grain-size compositions of the CRM powders were measured by different instrumental methods and assessed at different scales. The laser diffraction analyzer HELOS/BR was employed to accurately and rapidly measure the grain-size composition of CRM natural sample powders. New measurements confirm that the particle size distribution of CRMs of magmatic and metamorphic rocks and sediments of Lake Baikal developed 45 and 25 years ago, accordingly have not changed fundamentally. The multimodal distributions ofparticle sizes of investigated CRMs clearly reflect the differences in mineral and chemical compositions. Aggregating of the particles of different composition and origin during long-term storage of powders is not observed. The measurement results of particle size compositions of the CRM powders show a slight dependence on the weight put into the device, as well as its mineral composition. The homogeneity of the substance of studied standard samples was confirmed by low quantities of representative sub-samples (0.075-0.100 g for a wide range of elements determined by modern instrumental analytical methods. The use of laser diffraction analyzers type HELOS could help to certify the particle size composition of CRM powder as repeatable metrological characteristic.

  20. FIELD COMPARISONS OF DUAL SMPS-APS SYSTEMS TO MEASURE INDOOR-OUTDOOR PARTICLE SIZE DISTRIBUTIONS

    Science.gov (United States)

    Simultaneous measurements of particle size distributions across multiple locations can provide critical information to accurately assess human exposure to particles. These data are very useful to describe indoor-outdoor particle relationships, outdoor particle penetration thro...

  1. Initiator Systems Effect on Particle Coagulation and Particle Size Distribution in One-Step Emulsion Polymerization of Styrene

    Directory of Open Access Journals (Sweden)

    Baijun Liu

    2016-02-01

    Full Text Available Particle coagulation is a facile approach to produce large-scale polymer latex particles. This approach has been widely used in academic and industrial research owing to its higher polymerization rate and one-step polymerization process. Our work was motivated to control the extent (or time of particle coagulation. Depending on reaction parameters, particle coagulation is also able to produce narrowly dispersed latex particles. In this study, a series of experiments were performed to investigate the role of the initiator system in determining particle coagulation and particle size distribution. Under the optimal initiation conditions, such as cationic initiator systems or higher reaction temperature, the time of particle coagulation would be advanced to particle nucleation period, leading to the narrowly dispersed polymer latex particles. By using a combination of the Smoluchowski equation and the electrostatic stability theory, the relationship between the particle size distribution and particle coagulation was established: the earlier the particle coagulation, the narrower the particle size distribution, while the larger the extent of particle coagulation, the larger the average particle size. Combined with the results of previous studies, a systematic method controlling the particle size distribution in the presence of particle coagulation was developed.

  2. Luminescent Sensors for Tracking Spatial Particle Distribution in an Explosion

    Science.gov (United States)

    Eilers, Hergen; Gunawidjaja, Ray; Diez-Y-Riega, Helena; Svingala, Forrest; Daniels, Amber; Lightstone, James; Washington State University Collaboration; Nswc Iheodtd Collaboration

    2015-06-01

    We previously developed and tested thermally sensitive particles that, when seeded into an explosive event, flow with the expanding post-detonation fireball and provide ex-situ measurements of this thermal environment. This current work presents the development and testing of tracking particles that are used in concert with the thermally sensitive particles to encode the initial positions of materials recovered for ex-situ analysis. These tracking sensors consist of fully-crystallized (c) rare-earth-doped yttria particles such as c-Dy:Y2O3, c-Sm:Y2O3, and c-Er,Yb:Y2O3. The temperature sensors consist of mixtures of precursor (p) and fully crystallized materials such as p-Eu:Y2O3/c-Tb:Y2O3 orp-Eu:ZrO2/c-Tb:Y2O3. Three mixtures containing one of the tracking sensors and one of the temperature sensing mixtures are placed at different locations within the chamber. Post-detonation, the tracking particles in the debris are excited by 365 nm light, resulting in different color luminescence, and allowing for potential visual inspection of the particle distribution originating from the different locations. Meanwhile, the temperature is determined from spectral changes of the precursor sensor materials or by comparison of the precursor sensor materials with the Tb:Y2O3 intensity reference. Defense Threat Reduction Agency, HDTRA1-10-1-0005.

  3. Prediction of bulk powder flow performance using comprehensive particle size and particle shape distributions.

    Science.gov (United States)

    Yu, Weili; Muteki, Koji; Zhang, Lin; Kim, Gloria

    2011-01-01

    The purpose of this study is to establish a modeling approach that can be used to predict bulk powder flowability of pharmaceutical materials from their particle size and shape distributions. To build and validate the model, 23 commonly used pharmaceutical excipients and 38 binary blends were fully characterized for their particle size and shape distributions. The particle size and shape of each sample was characterized by multiple descriptors to fully reflect their morphological characteristics. The flow properties of these materials were analyzed using the Schulze Ring Shear Tester at a fixed humidity condition. A partial least squares (PLS) approach was used to build the mathematical model. Several different modeling approaches were attempted and the best method was identified as using a combination of formulation composition and particle size and shape distributions of single-component powder systems. The PLS model was shown to provide excellent predictions of powder flow function coefficient (FFC) of up to approximately 20. The results also revealed that both particle size and shape play an important role in determining the powder flow behavior. Copyright © 2010 Wiley-Liss, Inc. and the American Pharmacists Association

  4. Incidence and Distribution of Pulp Stones Found in Radiographic ...

    African Journals Online (AJOL)

    The overall incidence of pulp stones in the patients and their correlations between female and male patients and between the right‑side and left‑side occurrences were analyzed by computer program, SPSS 15. (SPSS Inc. Chicago, USA) with using the χ2 test. Differences were considered as significant when P < 0.05.

  5. Incidence and Distribution of Pulp Stones Found in Radiographic ...

    African Journals Online (AJOL)

    lower than the histologically observed incidence.[7] This was related to the fact that the ... Background: Pulp stones (PS) are discrete calcified masses found in the dental pulp, in the pulp tissue or become attached to or ... cavity or root canal, these stones often narrow or even obstruct the access to the apical point root canal.

  6. Distributed Particle Filter for Target Tracking: With Reduced Sensor Communications

    Directory of Open Access Journals (Sweden)

    Tadesse Ghirmai

    2016-09-01

    Full Text Available For efficient and accurate estimation of the location of objects, a network of sensors can be used to detect and track targets in a distributed manner. In nonlinear and/or non-Gaussian dynamic models, distributed particle filtering methods are commonly applied to develop target tracking algorithms. An important consideration in developing a distributed particle filtering algorithm in wireless sensor networks is reducing the size of data exchanged among the sensors because of power and bandwidth constraints. In this paper, we propose a distributed particle filtering algorithm with the objective of reducing the overhead data that is communicated among the sensors. In our algorithm, the sensors exchange information to collaboratively compute the global likelihood function that encompasses the contribution of the measurements towards building the global posterior density of the unknown location parameters. Each sensor, using its own measurement, computes its local likelihood function and approximates it using a Gaussian function. The sensors then propagate only the mean and the covariance of their approximated likelihood functions to other sensors, reducing the communication overhead. The global likelihood function is computed collaboratively from the parameters of the local likelihood functions using an average consensus filter or a forward-backward propagation information exchange strategy.

  7. Transverse energy distribution, charged particle multiplicities and spectra in 16O-nucleus collisions

    International Nuclear Information System (INIS)

    Sunier, J.W.

    1987-01-01

    The HELIOS (High Energy Lepton and Ion Spectrometer) experiment, installed at the CERN Super Proton Synchrotron, proposes to examine in details the physical properties of a state of high energy created in nuclei by ultra-relativistic nucleus-nucleus collisions. It is generally believed that, at high densities or temperatures, a phase transition to a plasma of quark and gluons will occur. The dynamic of the expansion of such a plasma and its subsequent condensation into a hadron gas should markedly affect the composition and momentum distribution of the emerging particles and photons. The HELIOS experimental setup therefore combines 4π calorimetric coverage with measurements of inclusive particle spectra, two particle correlations, low and high mass lepton pairs and photons. The emphasis is placed on transverse energy flow (E/sub T/) measurements with good energy resolution, and the ability to trigger the acquisition of data in a variety of E/sub T/ ranges, thereby selecting the impact parameter or the violence of the collisions. This short note presents HELIOS results, for the most part still preliminary, on 16 O-nucleus collisions at the incident energies of 60 and 200 GeV per nucleon. The E/sub T/ distributions from Al, Ag and W targets are discussed and compared to the associated charged particle multiplicities from W. Charged particle and (converted) photon spectra measured with the external magnetic spectrometer are compared for 16 O + W and p + W collisions at 200 GeV per nucleon. 5 refs., 7 figs

  8. Influence of particle size distribution on nanopowder cold compaction processes

    Science.gov (United States)

    Boltachev, G.; Volkov, N.; Lukyashin, K.; Markov, V.; Chingina, E.

    2017-06-01

    Nanopowder uniform and uniaxial cold compaction processes are simulated by 2D granular dynamics method. The interaction of particles in addition to wide-known contact laws involves the dispersion forces of attraction and possibility of interparticle solid bridges formation, which have a large importance for nanopowders. Different model systems are investigated: monosized systems with particle diameter of 10, 20 and 30 nm; bidisperse systems with different content of small (diameter is 10 nm) and large (30 nm) particles; polydisperse systems corresponding to the log-normal size distribution law with different width. Non-monotone dependence of compact density on powder content is revealed in bidisperse systems. The deviations of compact density in polydisperse systems from the density of corresponding monosized system are found to be minor, less than 1 per cent.

  9. A Novel Distributed Quantum-Behaved Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Yangyang Li

    2017-01-01

    Full Text Available Quantum-behaved particle swarm optimization (QPSO is an improved version of particle swarm optimization (PSO and has shown superior performance on many optimization problems. But for now, it may not always satisfy the situations. Nowadays, problems become larger and more complex, and most serial optimization algorithms cannot deal with the problem or need plenty of computing cost. Fortunately, as an effective model in dealing with problems with big data which need huge computation, MapReduce has been widely used in many areas. In this paper, we implement QPSO on MapReduce model and propose MapReduce quantum-behaved particle swarm optimization (MRQPSO which achieves parallel and distributed QPSO. Comparisons are made between MRQPSO and QPSO on some test problems and nonlinear equation systems. The results show that MRQPSO could complete computing task with less time. Meanwhile, from the view of optimization performance, MRQPSO outperforms QPSO in many cases.

  10. Distribution of pesticides in dust particles in urban environments.

    Science.gov (United States)

    Richards, Jaben; Reif, Ruben; Luo, Yuzhuo; Gan, Jay

    2016-07-01

    In regions with a mild climate, pesticides are often used around homes for pest control. Recent monitoring studies have linked pesticide use in residential areas to aquatic toxicity in urban surface water ecosystems, and suggested dust particles on paved surfaces as an important source of pesticides. To test the hypothesis that dust on hard surfaces is a significant source of pesticides, we evaluated spatial and temporal patterns of current-use insecticides in Southern California, and further explored their distribution as a function of particle sizes. Pyrethroid insecticides were detected in dust from the driveway, curb gutter and street at 53.5-94.8%, with median concentrations of 1-46 ng g(-1). Pyrethroid residues were uniformly distributed in areas adjacent to a house, suggesting significant redistribution. The total levels of pyrethroids in dust significantly (p fine particles that have a higher mobility in runoff than coarse particles. Results from this study highlight the widespread occurrence of pesticides in outdoor dust around homes and the potential contribution to downstream surface water contamination via rain-induced runoff. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Dual-cure luting composites: Part I: Filler particle distribution.

    Science.gov (United States)

    Inokoshi, S; Willems, G; Van Meerbeek, B; Lambrechts, P; Braem, M; Vanherle, G

    1993-03-01

    Fourteen dual-cure luting composites were analyzed for their filler particle shape, predominant and maximum filler size, and filler weight in function of their clinical use. Polished surfaces were etched with an argon ion beam and studied by means of scanning electron microscopy. The type of filler particles, either inorganic or prepolymerized, could clearly be recognized. Their shapes were angular, rounded or spherical, depending on the product. The maximum filler size varied extremely from less than 1 micron to 250 microns. A particle-size distribution analyser disclosed a bell-shaped filler-size distribution. The predominant filler size for all the products was much smaller than the maximum filler size. The filler weight varied from 36 to 77%. After ion etching, some products showed small areas with a low degree of filler loading. A classification of the luting composites based on the maximum filler size is proposed. Since the particle size varies widely within the group of products analyzed, a standard specification for luting composites is urgently needed.

  12. A novel method for determination of particle size distribution in-process

    Science.gov (United States)

    Salaoru, Tiberiu A.; Li, Mingzhong; Wilkinson, Derek

    2009-07-01

    The pharmaceutical and fine chemicals industries are strongly concerned with the manufacture of high value-added speciality products, often in solid form. On-line measurement of solid particle size is vital for reliable control of product properties. The established techniques, such as laser diffraction or spectral extinction, require dilution of the process suspension when measuring from typical manufacturing streams because of their high concentration. Dilution to facilitate measurement can result in changes of both size and form of particles, especially during production processes such as crystallisation. In spectral extinction, the degree of light scattering and absorption by a suspension is measured. However, for concentrated suspensions the interpretation of light extinction measurements is difficult because of multiple scattering and inter-particle interaction effects and at higher concentrations extinction is essentially total so the technique can no longer be applied. At the same time, scattering by a dispersion also causes a change of phase which affects the real component of the suspension's effective refractive index which is a function of particle size and particle and dispersant refractive indices. In this work, a novel prototype instrument has been developed to measure particle size distribution in concentrated suspensions in-process by measuring suspension refractive index at incidence angles near the onset of total internal reflection. Using this technique, the light beam does not pass through the suspension being measured so suspension turbidity does not impair the measurement.

  13. Nonequilibrium Microscopic Distribution of Thermal Current in Particle Systems

    KAUST Repository

    Yukawa, Satoshi

    2009-02-15

    A nonequilibrium distribution function of microscopic thermal current is studied by a direct numerical simulation in a thermal conducting steady state of particle systems. Two characteristic temperatures of the thermal current are investigated on the basis of the distribution. It is confirmed that the temperature depends on the current direction; Parallel temperature to the heat-flux is higher than antiparallel one. The difference between the parallel temperature and the antiparallel one is proportional to a macroscopic temperature gradient. ©2009 The Physical Society of Japan.

  14. Planning of distributed generation in distribution network based on improved particle swarm optimization algorithm

    Science.gov (United States)

    Li, Jinze; Qu, Zhi; He, Xiaoyang; Jin, Xiaoming; Li, Tie; Wang, Mingkai; Han, Qiu; Gao, Ziji; Jiang, Feng

    2018-02-01

    Large-scale access of distributed power can improve the current environmental pressure, at the same time, increasing the complexity and uncertainty of overall distribution system. Rational planning of distributed power can effectively improve the system voltage level. To this point, the specific impact on distribution network power quality caused by the access of typical distributed power was analyzed and from the point of improving the learning factor and the inertia weight, an improved particle swarm optimization algorithm (IPSO) was proposed which could solve distributed generation planning for distribution network to improve the local and global search performance of the algorithm. Results show that the proposed method can well reduce the system network loss and improve the economic performance of system operation with distributed generation.

  15. Design of neutral particle incident heating apparatus for large scale helical apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Osamu; Oka, Yoshihide; Osakabe, Masaki; Takeiri, Yasuhiko; Tsumori, Katsuyoshi; Akiyama, Ryuichi; Asano, Eiji; Kawamoto, Toshikazu; Kuroda, Tsutomu [National Inst. for Fusion Science, Nagoya (Japan)

    1997-02-01

    In the Institute of Nuclear Fusion Science, construction of the large scale helical apparatus has been progressed favorably, and constructions of the heating apparatus as well as of electron resonance apparatus were begun in their orders under predetermined manner since 1994 fiscal year. And, on 1995 fiscal year, construction of neutral particle incident heating apparatus, leading heat apparatus, was begun under 3 years planning. The plasma heating study system adopted the study results developed in this institute through the large scale hydrogen negative ion source and also adopted thereafter development on nuclear fusion study by modifying the original specification set at the beginning of the research plan before 7 years. As a result, system design was changed from initial 125 KeV to 180 KeV in the beam energy and to execute 15 MW incidence using two sets beam lines, to begin its manufacturing. Here is described on its new design with reason of its modifications. (G.K.)

  16. Benefit incidence analysis of free insecticide treated nets distribution ...

    African Journals Online (AJOL)

    2013-09-05

    Sep 5, 2013 ... Development Goal (MDG) 4 and 5 distributes free ITNs to pregnant mothers and under-five children in the Roll Back. Malaria programme (RBM). Aim: This study compared the benefit .... was pregnant women and mother‑child pair receiving antenatal care or routine childhood immunization from the public ...

  17. Comparing Multicomponent Erlang Distribution and Lévy Distribution of Particle Transverse Momentums

    International Nuclear Information System (INIS)

    Wei, Hua-Rong; Chen, Ya-Hui; Gao, Li-Na; Liu, Fu-Hu

    2014-01-01

    The transverse momentum spectrums of final-state products produced in nucleus-nucleus and proton-proton collisions at different center-of-mass energies are analyzed by using a multicomponent Erlang distribution and the Lévy distribution. The results calculated by the two models are found in most cases to be in agreement with experimental data from the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). The multicomponent Erlang distribution that resulted from a multisource thermal model seems to give a better description as compared with the Lévy distribution. The temperature parameters of interacting system corresponding to different types of final-state products are obtained. Light particles correspond to a low temperature emission, and heavy particles correspond to a high temperature emission. Extracted temperature from central collisions is higher than that from peripheral collisions

  18. [Size distribution of particle and polycyclic aromatic hydrocarbons in particle emissions from simulated emission sources].

    Science.gov (United States)

    Fu, Hai-Huan; Tian, Na; Shang, Hui-Bin; Zhang, Bin; Ye, Su-Fen; Chen, Xiao-Qiu; Wu, Shui-Ping

    2014-01-01

    Particles from cooking lampblack, biomass and plastics burning smoke, gasoline vehicular exhausts and gasoline generator exhausts were prepared in a resuspension test chamber and collected using a cascade MOUDI impactor. A total of 18 polycyclic aromatic hydrocarbons (PAHs) associated with particles were analyzed by GC-MS. The results showed that there were two peaks in the range of 0.44-1.0 microm and 2.5-10 microm for cooking lampblack, and only one peak in the range of 0.44-1.0 microm for straw and wood burning smoke. But there were no clear peak for plastics burning smoke. The peak for gasoline vehicular exhausts was found in the range of 2.5-10 microm due to the influence of water vapor associated with particles, while the particles from gasoline generator exhausts were mainly in the range of < or = 2.5 microm (accounting for 93% of the total mass). The peak in 2.5-10 microm was clear for cooking lampblack and gasoline vehicular exhausts. The peak in the range of 0.44-1.0 microm became more and more apparent with the increase of PAHs molecular weight. The fraction of PAH on particles less than 1.0 microm to that on the total particles increased along with PAH's molecular weight. Phenanthrene was the dominant compound for cooking lampblack and combustion smoke, while gasoline vehicular exhausts and generator exhausts were characterized with significantly high levels of naphthalene and benzo[g, h, i] perylene, respectively. The distribution of source characteristic ratios indicated that PAHs from cooking lampblack and biomass burning were close and they were different from those of vehicular exhausts and generator exhausts.

  19. The effects of laser beam incident angle and intensity distribution on Fabry-Perot etalon spectrum

    Science.gov (United States)

    Shen, Fahua; Wang, Yingying; Shi, Wenjuan; Chen, Ying; Liu, Mengling; Guo, Wenxin

    2017-11-01

    Fabry-Perot(F-P) etalon has important applications in laser detection, lidar and laser communication systems. In practical applications, the spectrum of the F-P etalon is affected by various factors, such as incident angle, divergence angle, spectral width, intensity distribution of the incident beam, absorption loss, surface defects of the plate and so on. The effects of the incident angle and the beam intensity distribution on F-P etalon spectrum are mainly analyzed. For the first time, taking into account both the beam incident angle and divergence angle, the precise analytical expression of the F-P etalon transmission spectrum is derived. For the Gaussian light intensity distribution, the precise analytical expression of the F-P etalon transmission spectrum is derived. The simulation analysis is carried out and the results are as follows. When the beam divergence angle is not zero, the incident angle increases, on the one hand, the center of the etalon spectrum is moved to the high frequency, and the frequency shift is linear with the square of the incident angle. The slope decreases with the increase of the divergence angle. On the other hand, resulting in peak reduction, spectral line broadening, and with the divergence angle increases, the more obvious the phenomenon. Considering the distribution of Gaussian light intensity, the spectrum of the etalon will be improved with the increase concentration of beam energy. On the one hand, the peak value is increased, the spectral line is narrowed and with the incidence angle increases, the degree of improvement is more obvious. On the one hand, the center of the spectrum moves toward the low frequency, but the larger the incident angle, the smaller the movement amount. The error of frequency discrimination or frequency locking by using the F-P etalon spectrum increases rapidly with the increase of the beam incident angle and beam divergence angle, and the Gaussian light intensity distribution beam can effectively

  20. A theory of the cancer age-specific incidence data based on extreme value distributions

    Directory of Open Access Journals (Sweden)

    Luis Soto-Ortiz

    2012-03-01

    Full Text Available The incidence of cancers varies with age, if normalized this is called the age-specific incidence. A mathematical model that describes this variation should provide a better understanding of how cancers develop. We suggest that the age-specific incidence should follow an extreme value distribution, based on three widely accepted assumptions: (1 a tumor develops from a single cell, (2 many potential tumor progenitor cells exist in a tissue, and (3 cancer is diagnosed when the first of these many potential tumor cells develops into a tumor. We tested this by comparing the predicted distribution to the age-specific incidence data for colon and prostate carcinomas collected by the Surveillance, Epidemiology and End Results network of 17 cancer registries. We found that colon carcinoma age-specific incidence data is consistent with an extreme value distribution, while prostate carcinomas age-specific incidence data generally follows the distribution. This model indicates that both colon and prostate carcinomas only occur in a subset of the population (22% for prostate and 13.5% for colon. Because of their very general nature, extreme value distributions might be applicable to understanding other chronic human diseases.

  1. High Deformability, Particle Size Distribution and Hydration of Phytoglycogen Nanoparticles

    Science.gov (United States)

    Baylis, Benjamin; Dutcher, John

    We have used atomic force microscopy to resolve a large discrepancy between the size of monodisperse phytoglycogen nanoparticles measured using small angle neutron scattering (SANS) and dynamic light scattering (DLS), and to calculate the effect of hydration on the nanoparticle size. The AFM measurements are challenging because of the ``stickiness'' and deformability of the soft nanoparticles. By significantly reducing the interaction between the AFM tip and the ``sticky'' nanoparticles, we were able to obtain high quality images in both air and water. We found that the adsorbed particles are highly deformed, forming pancake-like objects on hydrophilic mica surfaces. By measuring the distribution of isolated particle volumes in air, we calculated the average effective spherical diameter of the particles. Comparing nanoparticle aggregates in both air and water allowed the determination of the hydration of an individual nanoparticle. Our results are in excellent agreement with the diameter determined using SANS, providing insight into the unusual diffusion dynamics that is measured in DLS. These measurements illustrate the distinct advantages of AFM over other imaging techniques for visualizing nanoscopic soft objects in a liquid environment.

  2. Particle size distributions from laboratory-scale biomass fires using fast response instruments

    Science.gov (United States)

    S Hosseini; L. Qi; D. Cocker; D. Weise; A. Miller; M. Shrivastava; J.W. Miller; S. Mahalingam; M. Princevac; H. Jung

    2010-01-01

    Particle size distribution from biomass combustion is an important parameter as it affects air quality, climate modelling and health effects. To date, particle size distributions reported from prior studies vary not only due to difference in fuels but also difference in experimental conditions. This study aims to report characteristics of particle size distributions in...

  3. Stability of stationary and time-varying nongyrotropic particle distributions

    Directory of Open Access Journals (Sweden)

    A. L. Brinca

    Full Text Available The ubiquity of nongyrotropic particle populations in space plasmas warrants the study of their characteristics, in particular their stability. The unperturbed nongyrotropic distribution functions in homogeneous media without sources and sinks (closed phase space must be rotating and time-varying (TNG, whereas consideration of open phase spaces allows for the occurrence of homogeneous and stationary distributions (SNG. The free energy brought about by the introduction of gyrophase organization in a particle population can destabilize otherwise thoroughly stable magnetoplasmas (or, a fortiori, enhance pre-existing gyrotropic instabilities and feed intense wave growth both in TNG and SNG environments: The nongyrotropic (electron or ion species can originate unstable coupling among the gyrotropic characteristic waves. The stability properties of these two types of homogeneous nongyrotropy shall be contrasted for parallel (with respect to the ambient magnetic field and perpendicular propagation, and their potential role as wave activity sources shall be illustrated resorting to solutions of the appropriate dispersion equations and numerical simulations.

    Key words. Space plasma physics (waves and instabilities · Magnetospheric physics (plasma waves and instabilities · Interplanetary physics (plasma waves and turbulence

  4. Building predictive models of soil particle-size distribution

    Directory of Open Access Journals (Sweden)

    Alessandro Samuel-Rosa

    2013-04-01

    Full Text Available Is it possible to build predictive models (PMs of soil particle-size distribution (psd in a region with complex geology and a young and unstable land-surface? The main objective of this study was to answer this question. A set of 339 soil samples from a small slope catchment in Southern Brazil was used to build PMs of psd in the surface soil layer. Multiple linear regression models were constructed using terrain attributes (elevation, slope, catchment area, convergence index, and topographic wetness index. The PMs explained more than half of the data variance. This performance is similar to (or even better than that of the conventional soil mapping approach. For some size fractions, the PM performance can reach 70 %. Largest uncertainties were observed in geologically more complex areas. Therefore, significant improvements in the predictions can only be achieved if accurate geological data is made available. Meanwhile, PMs built on terrain attributes are efficient in predicting the particle-size distribution (psd of soils in regions of complex geology.

  5. PWR power distribution flattening using Quantum Particle Swarm intelligence

    International Nuclear Information System (INIS)

    Jamalipour, M.; Gharib, M.; Sayareh, R.; Khoshahval, F.

    2013-01-01

    Highlights: ► Quantum Particle Swarm Optimization (QPSO) is applied to ICFMO. ► A differential mutation operator is added to enhance QPSO performance (QPSO-DM). ► PSO, QPSO and QPSO-DM are tested on Bushehr Nuclear Power Plant (BNPP). ► It is observed that QPSO-DM is comparable to PSO and QPSO on ICFMO. - Abstract: In-core fuel management optimization (ICFMO) is one of the most challenging concepts of nuclear engineering. Most of the strategies implemented for optimizing fuel loading pattern in nuclear power reactors are based on maximizing core multiplication factor in order to extract maximum energy and reducing power peaking factor from a predetermined value to maintain fuel integrity. In this investigation a new method using Quantum Particle Swarm Optimization (QPSO) algorithm has been developed in order to flatten power density distribution in WWER-1000 Bushehr Nuclear Power Plant (BNPP) and thereby provide a better safety margin. The result and convergence of this method show that QPSO performs very well and is comparable to PSO. Furthermore, an operator has been added to QPSO as a mutation operator. This algorithm, called QPSO-DM, shows a better performance on ICFMO than PSO and QPSO. MATLAB software was used to map PSO, QPSO and QPSO-DM for loading pattern optimization. Multi-group constants generated by WIMS for different fuel configurations were fed into CITATION to obtain the power density distribution

  6. Shape, size, and distribution of magnetic particles in Bjurbole chondrules

    Science.gov (United States)

    Nava, David F.

    1994-01-01

    Chondrules from the Bjurbole chondritic meteorite (L4) exhibit saturation remanence magnetization (SIRM) values which vary over three orders of magnitude. REM values (Natural Remanence Magnetization/SIRM) for Allende (C3V) and Chainpur (LL3) are less than 0.01 but in Bjurbole some chondrules were found to have REM values greater than 0.1 with several greater than 0.2. REM values greater than 0.1 are abnormal and cannot be acquired during weak field cooling. If exposure to a strong field (whatever the source) during the chondrules' history is responsible for the high REM values, was such history associated with a different processing which might have resulted in different shape, size, and distribution of metal particles compared to chondrules having REM values of less than 0.01? Furthermore, magnetic hysteresis results show a broad range of magnetic hardness and other intrinsic magnetic properties. These features must be related to (1) size and amount of metal; and (2) properties of, and amount of, tetrataenite in the chondrules (all chondrules thus far subjected to thermomagnetic analysis show the presence of tetrataenite). A scanning electron microscopy (SEM) study is underway to determine the relationship between the shape, size, and distribution of metal particles within individual chondrules and the magnetic properties of these chondrules. Results from the SEM study in conjunction with magnetic property data may also help to discern effects from possible lightning strikes in the nebula prior to incorporation of the chondrules into the parent body.

  7. A hybrid mathematical model for controlling particle size, particle size distribution, and color properties of toner particles

    Science.gov (United States)

    Ataeefard, Maryam; Shadman, Alireza; Saeb, Mohammad Reza; Mohammadi, Yousef

    2016-08-01

    A mathematical modeling approach was proposed combining the capabilities of response surface methodology (RSM) and desirability function (DF) and implemented successfully in production of printing toner particles. Toner powders were systematically synthesized through suspension copolymerization process. Applying RSM, a series of experiments were designed and toner particles were prepared and the effects of monomer ratio, colorant and surfactant content on the particle size (PS), particle size distribution (PSD), thermal and colorimetric properties (∆ E) of the resulting toner were monitored and discussed. The second-order models corresponding to each target characteristic, i.e., PS, PSD, and ∆ E of different types of toner powders, were obtained by individual optimization to express variation of each property in terms of polymerization parameters. Applying statistical calculations, the best reduced models were identified to be fed in the second step of optimization. Since toners with appropriate PS, PSD, and CP were needed, we applied multi-objective optimization based on DF approach. The results show that exact tuning of toner properties is closely possible with the aid of hybrid mathematical model developed in this work. Noticeably, desirabilities are very close to 100 %.

  8. An alternative method for determining particle-size distribution of forest road aggregate and soil with large-sized particles

    Science.gov (United States)

    Hakjun Rhee; Randy B. Foltz; James L. Fridley; Finn Krogstad; Deborah S. Page-Dumroese

    2014-01-01

    Measurement of particle-size distribution (PSD) of soil with large-sized particles (e.g., 25.4 mm diameter) requires a large sample and numerous particle-size analyses (PSAs). A new method is needed that would reduce time, effort, and cost for PSAs of the soil and aggregate material with large-sized particles. We evaluated a nested method for sampling and PSA by...

  9. Particle size distributions in waters from a karstic aquifer: from particles to colloids

    Science.gov (United States)

    Atteia, O.; Kozel, R.

    1997-12-01

    Waters from the surface hydrologic network and the spring of a karstic aquifer in Switzerland were sampled to analyse their colloidal content. The measurements were done weekly with a single particle counter and were verified by other techniques. The particle size distribution (PSD) was modelled in two portions, below and above 5 μm, using two types of equation: a power law (Pareto distribution) and an exponential law. The model results matched well with the entire PSD data set by varying the parameter values. The parameters obtained from fitting the measured PSD curves were then interpreted in relation to environmental factors. It appears that the two parts of the curves vary independently. The first part of the PSD curve, relating to the smallest particles, is dependent on the pH value of the spring or the temperature of the surface brook. In contrast, the second part of the curve depends mostly on the spring discharge volume. During high flow events, the major effect of the discharge on particle size occurs during the rising limb of the hydrograph, interpreted as clays deposited in the aquifer and resuspended due to high water velocity. The contrasted behaviour of the two parts of the PSD curves suggested that the break point in the curves represents the limit between colloidal and particulate behaviour. Knowing these dependencies, and the characteristics of the particulate matter, allowed the estimation of the role of the colloids in contaminant transport. Large fluxes of suspended matter, specific to karstic aquifers, demonstrate the critical role of colloids in contaminant transport, which is markedly different from what typically occurs in porous media.

  10. Size distribution of radon daughter particles in uranium mine atmospheres

    International Nuclear Information System (INIS)

    George, A.C.; Hinchliffe, L.; Sladowski, R.

    1977-07-01

    An investigation of the particle size distribution and other properties of radon daughters in uranium mines was reported earlier but only summaries of the data were presented. This report consists mainly of tables of detailed measurements that were omitted in the original article. The tabulated data include the size distributions, uncombined fractions and ratios of radon daughters as well as the working levels, radon concentrations, condensation nuclei concentrations, temperature, and relative humidity. The measurements were made in 27 locations in four large underground mines in New Mexico during typical mining operations. The size distributions of the radon daughters were log normal. The activity median diameters ranged from 0.09 μm to 0.3 μm with a mean of 0.17 μm. Geometric standard deviations were from 1.3 to 4 with a mean of 2.7. Uncombined fractions expressed in accordance with the ICRP definition ranged from 0.004 to 0.16 with a mean of 0.04

  11. Mass size distribution of particle-bound water

    Science.gov (United States)

    Canepari, S.; Simonetti, G.; Perrino, C.

    2017-09-01

    The thermal-ramp Karl-Fisher method (tr-KF) for the determination of PM-bound water has been applied to size-segregated PM samples collected in areas subjected to different environmental conditions (protracted atmospheric stability, desert dust intrusion, urban atmosphere). This method, based on the use of a thermal ramp for the desorption of water from PM samples and the subsequent analysis by the coulometric KF technique, had been previously shown to differentiate water contributes retained with different strength and associated to different chemical components in the atmospheric aerosol. The application of the method to size-segregated samples has revealed that water showed a typical mass size distribution in each one of the three environmental situations that were taken into consideration. A very similar size distribution was shown by the chemical PM components that prevailed during each event: ammonium nitrate in the case of atmospheric stability, crustal species in the case of desert dust, road-dust components in the case of urban sites. The shape of the tr-KF curve varied according to the size of the collected particles. Considering the size ranges that better characterize the event (fine fraction for atmospheric stability, coarse fraction for dust intrusion, bi-modal distribution for urban dust), this shape is coherent with the typical tr-KF shape shown by water bound to the chemical species that predominate in the same PM size range (ammonium nitrate, crustal species, secondary/combustion species - road dust components).

  12. Electronic enclosure design using distributed particle swarm optimization

    Science.gov (United States)

    Scriven, Ian; Lu, Junwei; Lewis, Andrew

    2013-02-01

    This article proposes a method for designing electromagnetic compatibility shielding enclosures using a peer-to-peer based distributed optimization system based on a modified particle swarm optimization algorithm. This optimization system is used to obtain optimal solutions to a shielding enclosure design problem efficiently with respect to both electromagnetic shielding efficiency and thermal performance. During the optimization procedure it becomes evident that optimization algorithms and computational models must be properly matched in order to achieve efficient operation. The proposed system is designed to be tolerant of faults and resource heterogeneity, and as such would find use in environments where large-scale computing resources are not available, such as smaller engineering companies, where it would allow computer-aided design by optimization using existing resources with little to no financial outlay.

  13. ESTIMATING SOIL PARTICLE-SIZE DISTRIBUTION FOR SICILIAN SOILS

    Directory of Open Access Journals (Sweden)

    Vincenzo Bagarello

    2009-09-01

    Full Text Available The soil particle-size distribution (PSD is commonly used for soil classification and for estimating soil behavior. An accurate mathematical representation of the PSD is required to estimate soil hydraulic properties and to compare texture measurements from different classification systems. The objective of this study was to evaluate the ability of the Haverkamp and Parlange (HP and Fredlund et al. (F PSD models to fit 243 measured PSDs from a wide range of 38 005_Bagarello(547_33 18-11-2009 11:55 Pagina 38 soil textures in Sicily and to test the effect of the number of measured particle diameters on the fitting of the theoretical PSD. For each soil textural class, the best fitting performance, established using three statistical indices (MXE, ME, RMSE, was obtained for the F model with three fitting parameters. In particular, this model performed better in the fine-textured soils than the coarse-textured ones but a good performance (i.e., RMSE < 0.03 was detected for the majority of the investigated soil textural classes, i.e. clay, silty-clay, silty-clay-loam, silt-loam, clay-loam, loamy-sand, and loam classes. Decreasing the number of measured data pairs from 14 to eight determined a worse fitting of the theoretical distribution to the measured one. It was concluded that the F model with three fitting parameters has a wide applicability for Sicilian soils and that the comparison of different PSD investigations can be affected by the number of measured data pairs.

  14. Event-based total suspended sediment particle size distribution model

    Science.gov (United States)

    Thompson, Jennifer; Sattar, Ahmed M. A.; Gharabaghi, Bahram; Warner, Richard C.

    2016-05-01

    One of the most challenging modelling tasks in hydrology is prediction of the total suspended sediment particle size distribution (TSS-PSD) in stormwater runoff generated from exposed soil surfaces at active construction sites and surface mining operations. The main objective of this study is to employ gene expression programming (GEP) and artificial neural networks (ANN) to develop a new model with the ability to more accurately predict the TSS-PSD by taking advantage of both event-specific and site-specific factors in the model. To compile the data for this study, laboratory scale experiments using rainfall simulators were conducted on fourteen different soils to obtain TSS-PSD. This data is supplemented with field data from three construction sites in Ontario over a period of two years to capture the effect of transport and deposition within the site. The combined data sets provide a wide range of key overlooked site-specific and storm event-specific factors. Both parent soil and TSS-PSD in runoff are quantified by fitting each to a lognormal distribution. Compared to existing regression models, the developed model more accurately predicted the TSS-PSD using a more comprehensive list of key model input parameters. Employment of the new model will increase the efficiency of deployment of required best management practices, designed based on TSS-PSD, to minimize potential adverse effects of construction site runoff on aquatic life in the receiving watercourses.

  15. A Hot Spots Ignition Probability Model for Low-Velocity Impacted Explosive Particles Based on the Particle Size and Distribution

    Directory of Open Access Journals (Sweden)

    Hong-fu Guo

    2017-01-01

    Full Text Available Particle size and distribution play an important role in ignition. The size and distribution of the cyclotetramethylene tetranitramine (HMX particles were investigated by Laser Particle Size Analyzer Malvern MS2000 before experiment and calculation. The mean size of particles is 161 μm. Minimum and maximum sizes are 80 μm and 263 μm, respectively. The distribution function is like a quadratic function. Based on the distribution of micron scale explosive particles, a microscopic model is established to describe the process of ignition of HMX particles under drop weight. Both temperature of contact zones and ignition probability of powder explosive can be predicted. The calculated results show that the temperature of the contact zones between the particles and the drop weight surface increases faster and higher than that of the contact zones between two neighboring particles. For HMX particles, with all other conditions being kept constant, if the drop height is less than 0.1 m, ignition probability will be close to 0. When the drop heights are 0.2 m and 0.3 m, the ignition probability is 0.27 and 0.64, respectively, whereas when the drop height is more than 0.4 m, ignition probability will be close to 0.82. In comparison with experimental results, the two curves are reasonably close to each other, which indicates our model has a certain degree of rationality.

  16. The effect of particle size distributions on the microstructural evolution during sintering

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Tikare, V.; Frandsen, Henrik Lund

    2013-01-01

    Microstructural evolution and sintering behavior of powder compacts composed of spherical particles with different particle size distributions (PSDs) were simulated using a kinetic Monte Carlo model of solid state sintering. Compacts of monosized particles, normal PSDs with fixed mean particle ra...

  17. Characterization of spherical core–shell particles by static light scattering. Estimation of the core- and particle-size distributions

    International Nuclear Information System (INIS)

    Clementi, Luis A.; Vega, Jorge R.; Gugliotta, Luis M.; Quirantes, Arturo

    2012-01-01

    A numerical method is proposed for the characterization of core–shell spherical particles from static light scattering (SLS) measurements. The method is able to estimate the core size distribution (CSD) and the particle size distribution (PSD), through the following two-step procedure: (i) the estimation of the bivariate core–particle size distribution (C–PSD), by solving a linear ill-conditioned inverse problem through a generalized Tikhonov regularization strategy, and (ii) the calculation of the CSD and the PSD from the estimated C–PSD. First, the method was evaluated on the basis of several simulated examples, with polystyrene–poly(methyl methacrylate) core–shell particles of different CSDs and PSDs. Then, two samples of hematite–Yttrium basic carbonate core–shell particles were successfully characterized. In all analyzed examples, acceptable estimates of the PSD and the average diameter of the CSD were obtained. Based on the single-scattering Mie theory, the proposed method is an effective tool for characterizing core–shell colloidal particles larger than their Rayleigh limits without requiring any a-priori assumption on the shapes of the size distributions. Under such conditions, the PSDs can always be adequately estimated, while acceptable CSD estimates are obtained when the core/shell particles exhibit either a high optical contrast, or a moderate optical contrast but with a high ‘average core diameter’/‘average particle diameter’ ratio. -- Highlights: ► Particles with core–shell morphology are characterized by static light scattering. ► Core size distribution and particle size distribution are successfully estimated. ► Simulated and experimental examples are used to validate the numerical method. ► The positive effect of a large core/shell optical contrast is investigated. ► No a-priori assumption on the shapes of the size distributions is required.

  18. Chemical characterization, nano-particle mineralogy and particle size distribution of basalt dust wastes

    Energy Technology Data Exchange (ETDEWEB)

    Dalmora, Adilson C. [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração. Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Institute for Environmental Assessment and Water Studies (IDÆA), Spanish National Research Council (CSIC), C/Jordi Girona 18-26, 08034 Barcelona (Spain); Ramos, Claudete G.; Oliveira, Marcos L.S. [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração. Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Teixeira, Elba C. [Fundação Estadual de Proteção Ambiental Henrique Luis Roessler, Porto Alegre, RS (Brazil); Kautzmann, Rubens M.; Taffarel, Silvio R. [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração. Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Brum, Irineu A.S. de [Universidade Federal do Rio Grande do Sul, Escola de Engenharia, Departamento de Metalurgia, Centro de Tecnologia, Av. Bento Gonçalves, 9500. Bairro Agronomia. CEP: 91501-970 Porto Alegre, RS (Brazil); and others

    2016-01-01

    Understanding the geochemistry of basalt alteration is central to the study of agriculture systems. Various nano-minerals play an important role in the mobilization of contaminants and their subsequent uptake by plants. We present a new analytical experimental approach in combination with an integrated analytical protocol designed to study basalt alteration processes. Recently, throughout the world, ultra-fine and nano-particles derived from basalt dust wastes (BDW) during “stonemeal” soil fertilizer application have been of great concern for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the Nova Prata mining district in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/Energy Dispersive Spectroscopy (EDS)/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM/EDS), and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO{sub 2}, Al{sub 2}O{sub 3}, and Fe{sub 2}O{sub 3,} with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition, we have identified a number of trace metals such as Cd, Cu, Cr, and Zn, that are preferentially concentrated into the finer, inhalable, dust fraction and, thus, could present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle

  19. Chemical characterization, nano-particle mineralogy and particle size distribution of basalt dust wastes

    International Nuclear Information System (INIS)

    Dalmora, Adilson C.; Ramos, Claudete G.; Oliveira, Marcos L.S.; Teixeira, Elba C.; Kautzmann, Rubens M.; Taffarel, Silvio R.; Brum, Irineu A.S. de

    2016-01-01

    Understanding the geochemistry of basalt alteration is central to the study of agriculture systems. Various nano-minerals play an important role in the mobilization of contaminants and their subsequent uptake by plants. We present a new analytical experimental approach in combination with an integrated analytical protocol designed to study basalt alteration processes. Recently, throughout the world, ultra-fine and nano-particles derived from basalt dust wastes (BDW) during “stonemeal” soil fertilizer application have been of great concern for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the Nova Prata mining district in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/Energy Dispersive Spectroscopy (EDS)/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM/EDS), and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO 2 , Al 2 O 3 , and Fe 2 O 3, with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition, we have identified a number of trace metals such as Cd, Cu, Cr, and Zn, that are preferentially concentrated into the finer, inhalable, dust fraction and, thus, could present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle mineralogy and chemical

  20. Measurement of particle arrival time distribution in the vicinity of the core

    International Nuclear Information System (INIS)

    Yoshida, Mamoru; Kawamoto, Masaru

    1984-01-01

    Lately, the measurement of the arrival time distribution of air shower particles has become active, and the examples in which there were delayed particles in air shower have been reported. There were some events on which simple explanation seemed difficult. Taking notice of those anomalous events, Kobe University group obtained 7549 sheets of film data from 6162 events of the air showers from 2 x 10 4 to 5 x 10 7 size during 3647 effective measuring hours from January to autumn in 1982. The measuring equipment basically consisted of scintillation counters and storage oscillographs. Shower front thickness, double peak pulses that appeared in a specific detector, and double peak pulses that simultaneously appeared in more than one detector, were considered whether these are explained as normal phenomena, assuming three cases: completely independent two air showers are succeedingly incident in a period shorter than 100 ns; delay due to the difference in passing distances; and delayed two hadrons. The possibility that these explanations are valid was decided to be very little. In conclusion, the double peak pulse phenomena that appeared only in a single detector can be consistently explained with delayed hadrons in air showers, and it seems that the double peak pulse phenomena that simultaneously appeared in more than one detector suggest the possibility of existence of unknown superheavy particles whose mass is about 1 TeV, and their life is about 1 μs. (Wakatsuki, Y.)

  1. Methods for determining particle size distribution and growth rates between 1 and 3 nm using the Particle Size Magnifier

    CERN Document Server

    Lehtipalo, Katrianne; Kontkanen, Jenni; Kangasluoma, Juha; Franchin, Alessandro; Wimmer, Daniela; Schobesberger, Siegfried; Junninen, Heikki; Petäjä, Tuukka; Sipilä, Mikko; Mikkilä, Jyri; Vanhanen, Joonas; Worsnop, Douglas R; Kulmala, Markku

    2014-01-01

    The most important parameters describing the atmospheric new particle formation process are the particle formation and growth rates. These together determine the amount of cloud condensation nuclei attributed to secondary particle formation. Due to difficulties in detecting small neutral particles, it has previously not been possible to derive these directly from measurements in the size range below about 3 nm. The Airmodus Particle Size Magnifier has been used at the SMEAR II station in Hyytiälä, southern Finland, and during nucleation experiments in the CLOUD chamber at CERN for measuring particles as small as about 1 nm in mobility diameter. We developed several methods to determine the particle size distribution and growth rates in the size range of 1–3 nm from these data sets. Here we introduce the appearance-time method for calculating initial growth rates. The validity of the method was tested by simulations with the Ion-UHMA aerosol dynamic model.

  2. Coincidence between geographical distribution of Leptotrombidium scutellare and scrub typhus incidence in South Korea.

    Directory of Open Access Journals (Sweden)

    Jong Yul Roh

    Full Text Available To clarify the geographical distribution of scrub typhus vectors in Korea, a survey of larval trombiculid mites was conducted from 2005 to 2007 by collecting wild small mammals twice a year (spring and autumn at 24 sites nationwide. A total of 67,325 mites representing 4 genera and 14 species were collected from 783 trapped rodents, corresponding to a chigger index (number of chigger mites per rodent of 86.0. The predominant mite species were Leptotrombidium pallidum (52.6%, Leptotrombiduim scutellare (27.1%, Leptotrombidium palpale (8.2%, Leptotrombidium orientale (5.6%, and Neotrombicula tamiyai (1.7%. However, the proportions of L. scutellare in southern areas, including endemic provinces such as Jeollabuk-Do (34.3%, Jeollanam-Do (49.0%, and Gyeongsangnam-Do (88%, were relatively higher than in central Korean regions where L. pallidum was predominant. In autumn, the ratio of L. scutellare increased to 42% while the ratio of L. pallidum decreased. The geographical distribution map of the L. scutellare chigger index was identical to the incidence pattern of scrub typhus, whereas those of overall mites and L. pallidum showed no relationship with case incidence patterns. Distribution mapping analysis shows an identical geographical distribution of L. scutellare and epidemic incidence of scrub typhus in South Korea. L. pallidum could be another vector at all other parts of the Korean peninsula, including the eastern and northern regions that have a low level of scrub typhus incidence.

  3. Chemical characterization, nano-particle mineralogy and particle size distribution of basalt dust wastes.

    Science.gov (United States)

    Dalmora, Adilson C; Ramos, Claudete G; Oliveira, Marcos L S; Teixeira, Elba C; Kautzmann, Rubens M; Taffarel, Silvio R; de Brum, Irineu A S; Silva, Luis F O

    2016-01-01

    Understanding the geochemistry of basalt alteration is central to the study of agriculture systems. Various nano-minerals play an important role in the mobilization of contaminants and their subsequent uptake by plants. We present a new analytical experimental approach in combination with an integrated analytical protocol designed to study basalt alteration processes. Recently, throughout the world, ultra-fine and nano-particles derived from basalt dust wastes (BDW) during "stonemeal" soil fertilizer application have been of great concern for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the Nova Prata mining district in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/Energy Dispersive Spectroscopy (EDS)/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM/EDS), and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO2, Al2O3, and Fe2O3, with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition, we have identified a number of trace metals such as Cd, Cu, Cr, and Zn, that are preferentially concentrated into the finer, inhalable, dust fraction and, thus, could present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle mineralogy and chemical composition in

  4. Incidence trends and age distribution of colorectal cancer by subsite in Guangzhou, 2000-2011.

    Science.gov (United States)

    Zhou, Qin; Li, Ke; Lin, Guo-Zhen; Shen, Ji-Chuan; Dong, Hang; Gu, Yu-Ting; Liu, Hua-Zhang

    2015-08-06

    Colorectal cancer (CRC) is the third most common cancer in China. The incidence of CRC has been increasing in recent years. The aim of this study was to explore the incidence trends and the age distribution of CRC by subsite in Guangzhou between 2000 and 2011. A total of 22,432 incident cases of CRC between 2000 and 2011 from Guangzhou Cancer Registry were identified. Crude incidence and age-standardized rates (ASRs), using the Segi's world standard population, were calculated for CRC and CRC subsites. The incidence trend was analyzed and the annual percentage change (APC) in incidence was calculated by using JoinPoint software. The crude incidence increased significantly from 23.4/10(5) in 2000 to 37.4/10(5) in 2011 for males and from 20.9/10(5) to 30.5/10(5) for females. The ASRs of CRC incidence stabilized during the period of 2000-2011 for both males and females. The ages at the onset of CRC for both males and females during 2010-2011 were significantly higher compared with those during 2000-2002 (males: t = 1.95, P = 0.05; females: t = 6.03, P 2000-2004 and by 1.68% annually (P = 0.03) during 2005-2011. For females aged 65 years and older, the CRC incidence increased by 5.77% annually (P = 0.03) during 2000-2004. There were no significant changes for the CRC incidences in males aged 49 and younger and 65 years and older and females aged 64 years and younger during 2000-2004, or for those in all females as well as males aged 49 years and younger and 65 years and older during 2005-2011. The percentage of colon cancer in all CRCs increased significantly for both males and females between the periods of 2000-2002 and 2010-2011. The ASRs of descending colon and sigmoid colon cancer incidences increased significantly for females during 2005-2011 (APC, 5.51% and 1.08%, respectively, both P 2000 and 2011 because of the aging, whereas the ASRs kept stable. The percentage of colon cancer in all CRCs increased significantly. Further surveillance

  5. Particles size distribution effect on 3D packing of nanoparticles in to a bounded region

    International Nuclear Information System (INIS)

    Farzalipour Tabriz, M.; Salehpoor, P.; Esmaielzadeh Kandjani, A.; Vaezi, M. R.; Sadrnezhaad, S. K.

    2007-01-01

    In this paper, the effects of two different Particle Size Distributions on packing behavior of ideal rigid spherical nanoparticles using a novel packing model based on parallel algorithms have been reported. A mersenne twister algorithm was used to generate pseudo random numbers for the particles initial coordinates. Also, for this purpose a nano sized tetragonal confined container with a square floor (300 * 300 nm) were used in this work. The Andreasen and the Lognormal Particle Size Distributions were chosen to investigate the packing behavior in a 3D bounded region. The effects of particle numbers on packing behavior of these two Particle Size Distributions have been investigated. Also the reproducibility and the distribution of packing factor of these Particle Size Distributions were compared

  6. Activation energy of etching for CR-39 as a function of linear energy transfer of the incident particles

    CERN Document Server

    Awad, E M

    1999-01-01

    In this work, we have studied the effect of the radiation damage caused by the incident particles on the activation energy of etching for CR-39 samples. The damage produced by the incident particle is expressed in terms of the linear energy transfer (LET). CR-39 samples from American Acrylic were irradiated to three different LET particles. These are N (LET sub 2 sub 0 sub 0 = 20 KeV/mu m) as a light particle, Fe (LET sub 2 sub 0 sub 0 = 110 KeV/mu m) as a medium particle and fission fragments (ff) from a sup 2 sup 5 sup 2 Cf source as heavy particles. In general the bulk etch rate was calculated using the weight difference method and the track etch rate was determined using the track geometry at various temperatures (50-90 deg. C) and concentrations (4-9 N) of the NaOH etchant. The average activation energy E sub b related to the bulk etch rate v sub b was calculated from 1n v sub b vs. 1/T. The average activation energy E sub t related to the track etch rate v sub t was estimated from 1n v sub t vs. 1/T. It...

  7. Restoring the azimuthal symmetry of lateral distributions of charged particles in the range of the KASCADE-Grande experiment

    International Nuclear Information System (INIS)

    Sima, O.; Rebel, H.; Haungs, A.; Toma, G.; Manailescu, C.; Morariu, C.; Arteaga, J.C.; Bekk, K.; Bertaina, M.; Bluemer, J.; Bozdog, H.; Brancus, I.M.; Chiavassa, A.; Cosavella, F.; Souza, V. de; Doll, P.; Engel, R.; Finger, M.; Glasstetter, R.; Grupen, C.

    2011-01-01

    The reconstruction of Extensive Air Showers (EAS) observed by particle detectors at the ground is based on the characteristics of observables like the lateral particle density and the arrival times. The lateral densities, inferred for different EAS components from detector data, are usually parameterised by applying various lateral distribution functions (LDFs). The LDFs are used in turn for evaluating quantities like the total number of particles or the density at particular radial distances. Typical expressions for LDFs anticipate azimuthal symmetry of the density around the shower axis. The deviations of the lateral particle density from this assumption arising from various reasons are smoothed out in the case of compact arrays like KASCADE, but not in the case of arrays like Grande, which only sample a smaller part of the azimuthal variation. KASCADE-Grande, an extension of the former KASCADE experiment, is a multi-component Extensive Air Shower (EAS) experiment located at the Karlsruhe Institute of Technology (Campus North), Germany. The lateral distributions of charged particles are deduced from the basic information provided by the Grande scintillators - the energy deposits - first in the observation plane, then in the intrinsic shower plane. In all steps azimuthal dependences should be taken into account. As the energy deposit in the scintillators is dependent on the angles of incidence of the particles, azimuthal dependences are already involved in the first step: the conversion from the energy deposits to the charged particle density. This is done by using the Lateral Energy Correction Function (LECF) that evaluates the mean energy deposited by a charged particle taking into account the contribution of other particles (e.g. photons) to the energy deposit. By using a very fast procedure for the evaluation of the energy deposited by various particles we prepared realistic LECFs depending on the angle of incidence of the shower and on the radial and

  8. [Spatial distribution of accidents, incidents and diseases related to work in Peru, 2012-2014].

    Science.gov (United States)

    Hernández-Vásquez, Akram; Díaz-Seijas, Deysi; Vilcarromero, Stalin; Santero, Marilina

    2016-03-01

    We analyzed geospatially accidents, incidents and diseases related to work of regional reports in Peru (2012-2014). The 52887 events were classified as work related accidents (93%), dangerous incidents (5.1%), occupational diseases (1%) and fatal accidents (0.9%). The highest rates of fatal accidents were reported in Pasco, Callao, Lima, Moquegua and Arequipa. Callao and Lima are the regions with the highest rates of occupational accidents. The highest rates of dangerous incidents were reported in Arequipa, Callao, Lima, Ica and Piura. Occupational diseases are distributed with high rates in Huancavelica, Ancash, Pasco, Callao and Cusco. The economic activities that reported most of the occupational diseases were mining and quarrying (49.2%); followed by manufacturing industry (23.4%); and construction (8%). It is concluded that there are high rates and common spatial patterns of laboral accidents in Peru that could be used by decision makers to focus interventions.

  9. Size distributions of particles and their generating mechanisms

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler

    Summary of a lecture presented at the IAHR Workshop on Particle Motion and Sediment Transport: Measurement Techniques and Experimental Results, Schweiz, 5-8 April 1981......Summary of a lecture presented at the IAHR Workshop on Particle Motion and Sediment Transport: Measurement Techniques and Experimental Results, Schweiz, 5-8 April 1981...

  10. CIRCUMSOLAR ENERGETIC PARTICLE DISTRIBUTION ON 2011 NOVEMBER 3

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Herrero, R.; Blanco, J.J.; Rodríguez-Pacheco, J. [SRG, Universidad de Alcalá, E-28871 Alcalá de Henares (Spain); Dresing, N.; Klassen, A.; Heber, B.; Banjac, S. [IEAP, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel (Germany); Lario, D. [The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States); Agueda, N. [Departament d' Astronomia i Meteorologia. Institut de Ciències del Cosmos. Universitat de Barcelona, E-08028 Barcelona (Spain); Malandraki, O. E., E-mail: raul.gomezh@uah.es [IAASARS, National Observatory of Athens, GR-15236 Penteli (Greece)

    2015-01-20

    Late on 2011 November 3, STEREO-A, STEREO-B, MESSENGER, and near-Earth spacecraft observed an energetic particle flux enhancement. Based on the analysis of in situ plasma and particle observations, their correlation with remote sensing observations, and an interplanetary transport model, we conclude that the particle increases observed at multiple locations had a common single-source active region and the energetic particles filled a very broad region around the Sun. The active region was located at the solar backside (as seen from Earth) and was the source of a large flare, a fast and wide coronal mass ejection, and an EIT wave, accompanied by type II and type III radio emission. In contrast to previous solar energetic particle events showing broad longitudinal spread, this event showed clear particle anisotropies at three widely separated observation points at 1 AU, suggesting direct particle injection close to the magnetic footpoint of each spacecraft, lasting for several hours. We discuss these observations and the possible scenarios explaining the extremely broad particle spread for this event.

  11. Estimation of particle size distribution of nanoparticles from electrical ...

    Indian Academy of Sciences (India)

    MS received 9 January 2016; accepted 13 August 2017; published online 2 February 2018. Abstract. .... Figure 2. XRD of sample A. Table 1. Particle size and corresponding peak positions as found from XRD analysis. Peak position. Particle size (nm). 17.87 ... relation in measuring the data is the highest at this voltage.

  12. Pseudorapidity distributions of charged particles in Pb-Pb collisions at super proton synchrotron energies from the NA50 experiment

    CERN Document Server

    Idzik, M; Alessandro, B; Alexa, C; Arnaldi, R; Atayan, M; Baglin, C; Baldit, A; Bedjidian, Marc; Beolè, S; Boldea, V; Bordalo, P; Borges, G; Bussière, A; Capelli, L; Castanier, C; Castor, J I; Chaurand, B; Chevrot, I; Cheynis, B; Chiavassa, E; Cicalò, C; Claudino, T; Comets, M P; Constans, N; Constantinescu, S; Cortese, P; De Falco, A; De Marco, N; Dellacasa, G; Devaux, A; Dita, S; Drapier, O; Ducroux, L; Espagnon, B; Fargeix, J; Force, P; Gallio, M; Gavrilov, Yu K; Gerschel, C; Giubellino, P; Golubeva, M B; Gonin, M; Grigorian, A A; Grigorian, S; Grossiord, J Y; Guber, F F; Guichard, A; Gulkanian, H R; Hakobyan, R S; Haroutunian, R; Jouan, D; Karavitcheva, T L; Kluberg, L; Kurepin, A B; Le Bornec, Y; Lourenço, C; MacCormick, M; Macciotta, P; Marzari-Chiesa, A; Masera, M; Masoni, A; Monteno, M; Musso, A; Petiau, P; Piccotti, A; Pizzi, J R; Prado da Silva, W L; Prino, F; Puddu, G; Quintans, C; Ramello, L; Ramos, S; Rato-Mendes, P; Riccati, L; Romana, A; Santos, H; Saturnini, P; Scalas, E; Scomparin, E; Serci, S; Shahoyan, R; Sigaudo, F; Silva, S; Sitta, M; Sonderegger, P; Tarrago, X; Topilskaya, N S; Usai, G L; Vercellin, Ermanno; Villatte, L; Willis, N

    2003-01-01

    We present the measurements of charged particle pseudorapidity distributions dN/sub ch//d eta performed by the NA50 experiment in Pb-Pb collisions at the CERN SPS. Measurements were done at incident energies of 40 GeV ( square root s = 8.77 GeV) and 158 GeV ( square root s = 17.3 GeV) per nucleon over a broad impact parameter range. The multiplicity distributions are studied as a function of centrality using the number of participating nucleons (N/sub part/), or the number of binary nucleon-nucleon collisions (N/sub coll/). Their values at midrapidity exhibit a linear scaling with N/sub part/ at both energies. Particle yield increases approximately by a factor of 2 between square root s = 8.77 GeV and square root s = 17.3 GeV. (5 refs).

  13. Collisionless distribution function of charged particles ensemble in a tokamak magnetic configuration with magnetic island

    Science.gov (United States)

    Podturova, O. I.

    2017-10-01

    The collisionless distribution function of charged particle ensemble in the magnetic field of tokamak with a magnetic island is calculated. The calculation is based on the solution of the kinetic equation with source together with three-dimensional numerical calculations of charged particle trajectories. It is shown that in case of an inhomogeneous source trajectory, motion of trapped particles leads to anisotropization of the initially isotropic distribution of particle ensemble. The absence of contribution from the passing particles decreases the efficiency of spontaneous generation of a non-induction current in the magnetic island in comparison with the bootstrap effect in the system of nested magnetic surfaces.

  14. The effect of particle shape and size distribution on the acoustical properties of mixtures of hemp particles.

    Science.gov (United States)

    Glé, Philippe; Gourdon, Emmanuel; Arnaud, Laurent; Horoshenkov, Kirill-V; Khan, Amir

    2013-12-01

    Hemp concrete is an attractive alternative to traditional materials used in building construction. It has a very low environmental impact, and it is characterized by high thermal insulation. Hemp aggregate particles are parallelepiped in shape and can be organized in a plurality of ways to create a considerable proportion of open pores with a complex connectivity pattern, the acoustical properties of which have never been examined systematically. Therefore this paper is focused on the fundamental understanding of the relations between the particle shape and size distribution, pore size distribution, and the acoustical properties of the resultant porous material mixture. The sound absorption and the transmission loss of various hemp aggregates is characterized using laboratory experiments and three theoretical models. These models are used to relate the particle size distribution to the pore size distribution. It is shown that the shape of particles and particle size control the pore size distribution and tortuosity in shiv. These properties in turn relate directly to the observed acoustical behavior.

  15. Arrival time and incidence angle distributions of extensive air showers (EAS) muons

    International Nuclear Information System (INIS)

    Brancus, I.M.; Duma, M.; Vulpescu, B.; Foeller, M.; Rebel, H.; Voelker, G.; Chilingarian, A.A.

    1995-01-01

    The arrival time distributions of the muons can be related to the longitudinal EAS development and may provide additional information about the nature of the primary. Based on EAS simulations using the Monte-Carlo code CORSIKA, the correlations between arrival time and incidence angle distributions have been investigated in a case of a set of ideal detectors (10 m x 10 m) placed at various distances from the shower core. Applying advanced statistical techniques based on Bayes decision rule and non-parametric multivariate analysing methods it turns out that the correlations of muon arrival time and incidence angle at various separating distances of about 50 m exhibit promising features for mass discrimination (author)

  16. Experimental investigation of particle size distribution influence on diffusion controlled coarsening

    International Nuclear Information System (INIS)

    Fang, Zhigang; Patterson, B.R.

    1993-01-01

    The influence of initial particle size distribution on coarsening during liquid phase sintering has been experimentally investigated using W-14Ni-6Fe alloy as a model system. It was found that initially wider size distribution particles coarsened more rapidly than those of an initially narrow distribution. The well known linear relationship between the cube of the average particle radius bar r -3 , and time was observed for most of the coarsening process, although the early stage coarsening rate constant changed with time, as expected with concomitant early changes in the tungsten particle size distribution. The instantaneous transient rate constant was shown to be related to the geometric standard deviation, 1nσ, of the instantaneous size distributions, with higher rate constants corresponding to larger 1nσ values. The form of the particle size distributions changed rapidly during early coarsening and reached a quasi-stable state, different from the theoretical asymptotic distribution, after some time. A linear relationship was found between the experimentally observed instantaneous rate constant and that computed from an earlier model incorporating the effect of particle size distribution. The above results compare favorably with those from prior theoretical modeling and computer simulation studies of the effect of particle size distribution on coarsening, based on the DeHoff communicating neighbor model

  17. Effect of particle size distribution on permeability in the randomly packed porous media

    Science.gov (United States)

    Markicevic, Bojan

    2017-11-01

    An answer of how porous medium heterogeneity influences the medium permeability is still inconclusive, where both increase and decrease in the permeability value are reported. A numerical procedure is used to generate a randomly packed porous material consisting of spherical particles. Six different particle size distributions are used including mono-, bi- and three-disperse particles, as well as uniform, normal and log-normal particle size distribution with the maximum to minimum particle size ratio ranging from three to eight for different distributions. In all six cases, the average particle size is kept the same. For all media generated, the stochastic homogeneity is checked from distribution of three coordinates of particle centers, where uniform distribution of x-, y- and z- positions is found. The medium surface area remains essentially constant except for bi-modal distribution in which medium area decreases, while no changes in the porosity are observed (around 0.36). The fluid flow is solved in such domain, and after checking for the pressure axial linearity, the permeability is calculated from the Darcy law. The permeability comparison reveals that the permeability of the mono-disperse medium is smallest, and the permeability of all poly-disperse samples is less than ten percent higher. For bi-modal particles, the permeability is for a quarter higher compared to the other media which can be explained by volumetric contribution of larger particles and larger passages for fluid flow to take place.

  18. Gastrointestinal illness linked to incidents in drinking water distribution networks in Sweden.

    Science.gov (United States)

    Säve-Söderbergh, Melle; Bylund, John; Malm, Annika; Simonsson, Magnus; Toljander, Jonas

    2017-10-01

    During recent years, knowledge gaps on drinking water-related gastrointestinal illness have been identified, especially for non-epidemic cases. Pathogen contamination of drinking water during distribution has been suggested to contribute to these cases, but the risk factors are not yet fully understood. During 2014-2015, we conducted an epidemiological study in five municipalities in Sweden, to assess whether incidents in the drinking water distribution system influence the risk of gastrointestinal illness. Telephone interviews were conducted in the affected areas and in reference areas 7-14 days after a reported incident. Symptoms of gastrointestinal illness occurring during the period were documented for each household member. The results showed a significantly elevated risk of vomiting and acute gastrointestinal illness (AGI) in the affected areas, compared to the reference areas (OR vom.  = 2.0, 95% CI: 1.2-3.3; OR AGI  = 1.9, 95% CI: 1.2-3.0). Certain conditions, or risk factors, during the incidents, such as sewage and drinking water pipelines at the same level in the trench, were associated with an elevated risk of AGI and vomiting. Safety measures taken during repair work, like flushing, were also associated with an elevated risk of AGI and vomiting. These results show that incidents in the drinking water distribution network contribute to endemic gastrointestinal illness, especially AGI and vomiting, and that external pathogen contamination of the drinking water is a likely cause of these cases of gastrointestinal illness. The results also indicate that safety measures used today may not be sufficient for eliminating the risk of gastrointestinal illness. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. The spatial heterogeneity between Japanese encephalitis incidence distribution and environmental variables in Nepal.

    Directory of Open Access Journals (Sweden)

    Daniel E Impoinvil

    Full Text Available To identify potential environmental drivers of Japanese Encephalitis virus (JE transmission in Nepal, we conducted an ecological study to determine the spatial association between 2005 Nepal JE incidence, and climate, agricultural, and land-cover variables at district level.District-level data on JE cases were examined using Local Indicators of Spatial Association (LISA analysis to identify spatial clusters from 2004 to 2008 and 2005 data was used to fit a spatial lag regression model with climate, agriculture and land-cover variables.Prior to 2006, there was a single large cluster of JE cases located in the Far-West and Mid-West terai regions of Nepal. After 2005, the distribution of JE cases in Nepal shifted with clusters found in the central hill areas. JE incidence during the 2005 epidemic had a stronger association with May mean monthly temperature and April mean monthly total precipitation compared to mean annual temperature and precipitation. A parsimonious spatial lag regression model revealed, 1 a significant negative relationship between JE incidence and April precipitation, 2 a significant positive relationship between JE incidence and percentage of irrigated land 3 a non-significant negative relationship between JE incidence and percentage of grassland cover, and 4 a unimodal non-significant relationship between JE Incidence and pig-to-human ratio.JE cases clustered in the terai prior to 2006 where it seemed to shift to the Kathmandu region in subsequent years. The spatial pattern of JE cases during the 2005 epidemic in Nepal was significantly associated with low precipitation and the percentage of irrigated land. Despite the availability of an effective vaccine, it is still important to understand environmental drivers of JEV transmission since the enzootic cycle of JEV transmission is not likely to be totally interrupted. Understanding the spatial dynamics of JE risk factors may be useful in providing important information to the

  20. Collisional effects on ion energy and angular distributions incident on RF-biased electrodes

    International Nuclear Information System (INIS)

    Qiu Huatan; Wang Younian; Ma Tengcai

    2002-01-01

    Taking into account elastic collisions and charge-exchange collisions between ions and neutral particles, the authors established a self-consistent model describing the dynamics of radio-frequency (RF) sheath driven by a sinusoidal current source, and also, using the Monte-Carlo Method, simulated energy and angle distributions of ions bombarding on RF-biased substrates. It has been shown from numerical results that as increasing the discharge pressure, bimodal-peaks distributions for the ion energy become gradually a single-peak distribution, and low-energy ions increase. The authors also found that the angle distribution of ions is narrow and almost do not change with increasing the discharge pressure

  1. Early-stage evolution of particle size distribution with Johnson's SB function due to Brownian coagulation

    International Nuclear Information System (INIS)

    Tang Hong; Lin Jianzhong

    2013-01-01

    The moment method can be used to determine the time evolution of particle size distribution due to Brownian coagulation based on the general dynamic equation (GDE). But the function form of the initial particle size distribution must be determined beforehand for the moment method. If the assumed function type of the initial particle size distribution has an obvious deviation from the true particle population, the evolution of particle size distribution may be different from the real evolution tendency. Thus, a simple and general method is proposed based on the moment method. In this method, the Johnson's S B function is chosen as a general distribution function to fit the initial distributions including the log normal (L-N), Rosin–Rammler (R-R), normal (N-N) and gamma distribution functions, respectively. Meanwhile, using the modified beta function to fit the L-N, R-R, N-N and gamma functions is also conducted as a comparison in order to present the advantage of the Johnson's S B function as the general distribution function. And then, the time evolution of particle size distributions using the Johnson's S B function as the initial distribution can be obtained by several lower order moment equations of the Johnson's S B function in conjunction with the GDE during the Brownian coagulation process. Simulation experiments indicate that fairly reasonable results of the time evolution of particle size distribution can be obtained with this proposed method in the free molecule regime, transition regime and continuum plus near continuum regime, respectively, at the early time stage of evolution. The Johnson's S B function has the ability of describing the early time evolution of different initial particle size distributions. (paper)

  2. Control over particle size distribution by autoclaving poloxamer-stabilized trimyristin nanodispersions

    DEFF Research Database (Denmark)

    Göke, Katrin; Roese, Elin; Arnold, Andreas

    2016-01-01

    into the bloodstream. Consequently, small particles with a narrow particle size distribution are desired. Hitherto, there are, however, only limited possibilities for the preparation of monodisperse, pharmaceutically relevant dispersions. In this work, the effect of autoclaving at 121 °C on the particle size...... distribution of lipid nanoemulsions and -suspensions consisting of the pharmaceutically relevant components trimyristin and poloxamer 188 was studied. Additionally, the amount of emulsifier needed to stabilize both untreated and autoclaved particles was assessed. In our study, four dispersions of mean particle...... sizes from 45 to 150 nm were prepared by high-pressure melt homogenization. The particle size distribution before and after autoclaving was characterized using static and dynamic light scattering, differential scanning calorimetry, and transmission electron microscopy. Asymmetrical flow field...

  3. Statistical mechanics of the distribution of charge on particles in complex plasmas

    International Nuclear Information System (INIS)

    Sodha, M S; Mishra, S K; Misra, Shikha

    2011-01-01

    This paper presents an analytical study of the distribution of charge on the particles in a complex plasma; the study is based on statistical mechanics and ensures that the charge on the particles is an integral multiple of the electronic charge. The formulation incorporates both the number and energy balance of electrons/ions. Three specific cases of charging of particles have been considered, namely (i) in a plasma in the absence of electron emission from the particles, (ii) in a complex plasma in thermal equilibrium and (iii) in a complex plasma irradiated by monochromatic radiation, causing photoelectric emission of electrons from the particles. The effect of various parameters on the charge distribution has also been investigated. This paper is in reasonably good agreement with the fluctuation theory for large values of Z (Ze is the charge on a particle). It is seen that under certain conditions, a significant number of oppositely charged particles occur in the complex plasma.

  4. Modeling and experiments of the adhesion force distribution between particles and a surface.

    Science.gov (United States)

    You, Siming; Wan, Man Pun

    2014-06-17

    Due to the existence of surface roughness in real surfaces, the adhesion force between particles and the surface where the particles are deposited exhibits certain statistical distributions. Despite the importance of adhesion force distribution in a variety of applications, the current understanding of modeling adhesion force distribution is still limited. In this work, an adhesion force distribution model based on integrating the root-mean-square (RMS) roughness distribution (i.e., the variation of RMS roughness on the surface in terms of location) into recently proposed mean adhesion force models was proposed. The integration was accomplished by statistical analysis and Monte Carlo simulation. A series of centrifuge experiments were conducted to measure the adhesion force distributions between polystyrene particles (146.1 ± 1.99 μm) and various substrates (stainless steel, aluminum and plastic, respectively). The proposed model was validated against the measured adhesion force distributions from this work and another previous study. Based on the proposed model, the effect of RMS roughness distribution on the adhesion force distribution of particles on a rough surface was explored, showing that both the median and standard deviation of adhesion force distribution could be affected by the RMS roughness distribution. The proposed model could predict both van der Waals force and capillary force distributions and consider the multiscale roughness feature, greatly extending the current capability of adhesion force distribution prediction.

  5. Evaluate an impact of incident alpha particle and gamma ray on human blood components: A comparison study

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Asaad H.; Yaba, Sardar P.; Ismail, Haider J. [Medical Physics Research Group, Physics Department, Education College, Salahaddin University-Erbil, Iraqi Kurdistan (Iraq)

    2015-07-01

    An impact of alpha and gamma irradiation on human blood components have been evaluated and compared for healthy blood samples (male and females). Irradiation dose and time of irradiation calibrated and considered as a main comparison factors. Density of blood components measured for each in vitro irradiation before and after irradiation for males and females. Survey radiation dosimeter (Inspector Exp) and nuclear track detectors type CR-39 used to evaluate exposure dose rate and incident density of alpha particles, respectively. Experiment results verified that the irradiation of blood makes ionizing of blood components, either alpha or gamma irradiation dose, and the impacts of ionizing radiation were relativity for WBC, RBC, and PLT. Limited irradiation doses of 1-5 μSv/hr considered as a low radiation dose of alpha and gamma radiation sources ({sup 226}Ra, and {sup 137}Cs). Density of alpha particles accumulated on the blood surface was 34 (alpha particle/cm{sup 2}) for selected dose of incident alpha particle. Optimum value of irradiation dose and time of irradiation were 5 μSv/hr and 4 second for males and females. On the other hands, the values of irradiation dose and time of irradiation were 2.1 μSv/hr and 2 second for males and females for gamma irradiation. Thus, present results demonstrated that densities of RBC and WBC cells are capable of inducing reproduction in vitro for both type of irradiation. (authors)

  6. A Review of Discrete Element Method (DEM) Particle Shapes and Size Distributions for Lunar Soil

    Science.gov (United States)

    Lane, John E.; Metzger, Philip T.; Wilkinson, R. Allen

    2010-01-01

    As part of ongoing efforts to develop models of lunar soil mechanics, this report reviews two topics that are important to discrete element method (DEM) modeling the behavior of soils (such as lunar soils): (1) methods of modeling particle shapes and (2) analytical representations of particle size distribution. The choice of particle shape complexity is driven primarily by opposing tradeoffs with total number of particles, computer memory, and total simulation computer processing time. The choice is also dependent on available DEM software capabilities. For example, PFC2D/PFC3D and EDEM support clustering of spheres; MIMES incorporates superquadric particle shapes; and BLOKS3D provides polyhedra shapes. Most commercial and custom DEM software supports some type of complex particle shape beyond the standard sphere. Convex polyhedra, clusters of spheres and single parametric particle shapes such as the ellipsoid, polyellipsoid, and superquadric, are all motivated by the desire to introduce asymmetry into the particle shape, as well as edges and corners, in order to better simulate actual granular particle shapes and behavior. An empirical particle size distribution (PSD) formula is shown to fit desert sand data from Bagnold. Particle size data of JSC-1a obtained from a fine particle analyzer at the NASA Kennedy Space Center is also fitted to a similar empirical PSD function.

  7. Gas-particle phase partitioning and particle size distribution of chlorinated and brominated polycyclic aromatic hydrocarbons in haze.

    Science.gov (United States)

    Jin, Rong; Zheng, Minghui; Yang, Hongbo; Yang, Lili; Wu, Xiaolin; Xu, Yang; Liu, Guorui

    2017-12-01

    Chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/Br-PAHs) are emerging semi-volatile organic pollutants in haze-associated particulate matter (PM). Their gas-particle phase partitioning and distribution among PM fractions have not been clarified. Clarification would increase understanding of atmospheric behavior and health risks of Cl/Br-PAHs. In this study, samples of the gas phase and 4 PM phases (aerodynamic diameters (d ae ) > 10 μm, 2.5-10 μm, 1.0-2.5 μm, and distribution indicated that the Cl/Br-PAHs tended to adhere to fine particles. Over 80% of the Cl-PAHs and 70% of the Br-PAHs were associated with fine PM (d ae  gas-particle phase partitioning and PM distribution of Cl/Br-PAHs when heating of buildings was required, which was associated with haze events, were obviously different from those when heating was not required. The relationship between the logarithmic geometric mean diameters of the Cl/Br-PAH congeners and reciprocal of the temperature (1/T) suggested that low air temperatures during the heating period could lead to high proportions of Cl/Br-PAHs in the fine particles. Increased coal burning during the heating period also contributed to high Cl/Br-PAH loads in the fine particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. On the momentum distribution of particles participating in nuclear ...

    Indian Academy of Sciences (India)

    28Ni+58. 28. Ni using stopping parameter VARXZ. Various momentum constraints were imposed to get better insight into the stopping. The comparison of measured and calculated values of stopping for protons reveals the significance of these constraints. Maximum stopping is obtained for the particles lying in the lowest.

  9. Fragment and particle size distribution of impacted ceramic tiles

    NARCIS (Netherlands)

    Carton, E.P.; Weerheijm, J.; Ditzhuijzen, C.; Tuinman, I.

    2014-01-01

    The fragmentation of ceramic tiles under ballistic impact has been studied. Fragments and aerosol (respirable) particles were collected and analyzed to determine the total surface area generated by fracturing (macro-cracking and comminution) of armor grade ceramics. The larger fragments were

  10. On the momentum distribution of particles participating in nuclear ...

    Indian Academy of Sciences (India)

    literature as sensitive probes to study various aspects of nuclear matter at intermediate energies. One of the essential observables, which is necessary to understand the basic reaction dynamics, is the nuclear stopping: a prime source of information for analysing the energy spectra as well as the particle densities of the ...

  11. Evolution of the sedimentation technique for particle size distribution analysis

    International Nuclear Information System (INIS)

    Maley, R.

    1998-01-01

    After an introduction on the significance of particle size measurements, sedimentation methods are described, with emphasis on the evolution of the gravitational approach. The gravitational technique based on mass determination by X-ray adsorption allows fast analysis by automation and easy data handling, in addition to providing the accuracy required by quality control and research applications [it

  12. On Pair-Particle Distribution in Imperfect Bose Gas

    OpenAIRE

    Shanenko, A. A.

    1996-01-01

    A simple model of estimating the radial distribution function of an imperfect Bose gas in the ground state is presented. The model is based on integro-differential equations derived by considering the space boson distribution in an external field. With the approach proposed, the particular case of dilute Bose gas is investigated within the hard sphere approximation and beyond.

  13. Equilibrium distributions of free charged particles and molecules in systems with non-plane boundaries

    International Nuclear Information System (INIS)

    Usenko, A.S.

    1995-01-01

    The equilibrium space-inhomogeneous distributions of free and pair bound charged particles are calculated in the dipole approximation for the plasma-molecular cylinder and sphere. It is shown that the space and orientational distributions of charged particles and molecules in these systems are similar to those in the cases of plasma-molecular system restricted by one or two parallel planes. The influence of the parameters of outer medium and a plasma-molecular system on the space and orientational distributions of charged particles and molecules is studied in detail

  14. Physicochemical characterization of Capstone depleted uranium aerosols II: particle size distributions as a function of time.

    Science.gov (United States)

    Cheng, Yung Sung; Kenoyer, Judson L; Guilmette, Raymond A; Parkhurst, Mary Ann

    2009-03-01

    The Capstone Depleted Uranium (DU) Aerosol Study, which generated and characterized aerosols containing DU from perforation of armored vehicles with large-caliber DU penetrators, incorporated a sampling protocol to evaluate particle size distributions. Aerosol particle size distribution is an important parameter that influences aerosol transport and deposition processes as well as the dosimetry of the inhaled particles. These aerosols were collected on cascade impactor substrates using a pre-established time sequence following the firing event to analyze the uranium concentration and particle size of the aerosols as a function of time. The impactor substrates were analyzed using proportional counting, and the derived uranium content of each served as input to the evaluation of particle size distributions. Activity median aerodynamic diameters (AMADs) of the particle size distributions were evaluated using unimodal and bimodal models. The particle size data from the impactor measurements were quite variable. Most size distributions measured in the test based on activity had bimodal size distributions with a small particle size mode in the range of between 0.2 and 1.2 microm and a large size mode between 2 and 15 microm. In general, the evolution of particle size over time showed an overall decrease of average particle size from AMADs of 5 to 10 microm shortly after perforation to around 1 microm at the end of the 2-h sampling period. The AMADs generally decreased over time because of settling. Additionally, the median diameter of the larger size mode decreased with time. These results were used to estimate the dosimetry of inhaled DU particles.

  15. Angular distributions of sputtered particles from NiTi alloy

    International Nuclear Information System (INIS)

    Neshev, I.; Hamishkeev, V.; Chernysh, V.S.; Postnikov, S.; Mamaev, B.

    1993-01-01

    The angular distributions of sputtered Ni and Ti from a polycrystalline NiTi (50-50%) alloy are investigated by Auger electron spectroscopy and Rutherford backscattering spectroscopy. A difference in the angular distributions is observed with Ni being sputtered preferentially near the surface normal. A computer program for the calculation of the angular distributions of constituents sputtered from binary targets is created and used. The mechanisms responsible for the observed differences in the angular distributions are discussed. It is found that the collisional cascade theory is not directly applicable to the results of the constituents' angular distributions obtained in the presence of oxygen. The fitted coefficients of bombardment-induced segregation are found to be greater than the experimentally obtained ones. (author)

  16. A Correction of Random Incidence Absorption Coefficients for the Angular Distribution of Acoustic Energy under Measurement Conditions

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2009-01-01

    Most acoustic measurements are based on an assumption of ideal conditions. One such ideal condition is a diffuse and reverberant field. In practice, a perfectly diffuse sound field cannot be achieved in a reverberation chamber. Uneven incident energy density under measurement conditions can cause...... discrepancies between the measured value and the theoretical random incidence absorption coefficient. Therefore the angular distribution of the incident acoustic energy onto an absorber sample should be taken into account. The angular distribution of the incident energy density was simulated using the beam...... tracing method for various room shapes and source positions. The averaged angular distribution is found to be similar to a Gaussian distribution. As a result, an angle-weighted absorption coefficient was proposed by considering the angular energy distribution to improve the agreement between...

  17. The Orientation Distribution of Nonspherical Aerosol Particles within a Cloud.

    Science.gov (United States)

    1984-12-01

    a . a component of the fluid velocity). The use of the solution is based on the estimate that, even for the highest ( Kolmogoroff ) frequency...average of F, ( r(CJ) ,~ ,It ),for a space -time point is actually F (wx ,) for that point and that t’ ’ - D F V (3) The particles considered were...taken to be much smaller than the Kolmogoroff scale; so, the turbulent rotational diffusion coefficient itself, r was assumed in the second model to

  18. Particle size distribution and physico-chemical composition of clay.

    African Journals Online (AJOL)

    HP USER

    <300µm, <106µm, <63µm and <44µm respectively. There was no remarkable difference in silica (SiO2) as particle fractions reduced from <. 300µm - < 106µm - < 63µm but an observed. Table 1.0 Chemical composition of crude clay. Component wt (%). SiO2. 38.48. Al2O3. 12.46. Fe2O3. 6.18. TiO2. 1.85. MgO. 14.67. CaO.

  19. Influence of stirring speed on SiC particles distribution in A356 liquid

    Directory of Open Access Journals (Sweden)

    Yao Shasha

    2012-05-01

    Full Text Available A straight-blade mechanical stirrer was designed to stir A356-3.5vol%SiCp liquid in a cylindrical crucible with the capability of systematically investigating the influence of rotating speed of stirrer on the distribution of SiC particles in A356 liquid. The experimental results show that the vertical distribution of SiC particles in A356 liquid can be uniform when the rotating speed of stirrer is 200 rpm, but the radial distribution of SiC particles in A356 liquid is always nonhomogeneous regardless of the rotating speed of stirrer. The radial centrifugalization ratio of SiC particles in A356 liquid between the center and the periphery of crucible increases with the rotating speed of stirrer. The results were explained in the light of SiC particles motion subject to a combination of stirring and centrifugal effect.

  20. A comparative study of submicron particle sizing platforms: accuracy, precision and resolution analysis of polydisperse particle size distributions.

    Science.gov (United States)

    Anderson, Will; Kozak, Darby; Coleman, Victoria A; Jämting, Åsa K; Trau, Matt

    2013-09-01

    The particle size distribution (PSD) of a polydisperse or multimodal system can often be difficult to obtain due to the inherent limitations in established measurement techniques. For this reason, the resolution, accuracy and precision of three new and one established, commercially available and fundamentally different particle size analysis platforms were compared by measuring both individual and a mixed sample of monodisperse, sub-micron (220, 330, and 410 nm - nominal modal size) polystyrene particles. The platforms compared were the qNano Tunable Resistive Pulse Sensor, Nanosight LM10 Particle Tracking Analysis System, the CPS Instruments's UHR24000 Disc Centrifuge, and the routinely used Malvern Zetasizer Nano ZS Dynamic Light Scattering system. All measurements were subjected to a peak detection algorithm so that the detected particle populations could be compared to 'reference' Transmission Electron Microscope measurements of the individual particle samples. Only the Tunable Resistive Pulse Sensor and Disc Centrifuge platforms provided the resolution required to resolve all three particle populations present in the mixed 'multimodal' particle sample. In contrast, the light scattering based Particle Tracking Analysis and Dynamic Light Scattering platforms were only able to detect a single population of particles corresponding to either the largest (410 nm) or smallest (220 nm) particles in the multimodal sample, respectively. When the particle sets were measured separately (monomodal) each platform was able to resolve and accurately obtain a mean particle size within 10% of the Transmission Electron Microscope reference values. However, the broadness of the PSD measured in the monomodal samples deviated greatly, with coefficients of variation being ~2-6-fold larger than the TEM measurements across all four platforms. The large variation in the PSDs obtained from these four, fundamentally different platforms, indicates that great care must still be taken in

  1. Elemental particle size distributions. Measured and estimated dry deposition in Sfax region (Tunisia)

    Science.gov (United States)

    Masmoudi, M.; Belghith, I.; Chaabane, M.

    Mass size distribution of the crustal elements (Al, Ca, Fe, Mg, Si, Ti), anthropogenic elements (Zn, Mn, Cr, Cu, K, P, Pb) and sea elements (Na, Cl) were obtained from measurements carried out with an inertial cascade impactor in Sfax. A fitting procedure by data inversion was applied to those data. This procedure yields accurate size distributions of aerosols in the diameter range 0.1-25 μm in two different sites. In a coastal industrial site, the mass distribution of the aerosol showed a bimodal structure; and in urban area, the lower particle mode cannot be observed. The elemental dry deposition flux was calculated as a function of particle size. The element flux size distribution increased rapidly with particle size. The modelling results indicate that the majority of the crustal and anthropogenic elements flux (>90%) was due to particles larger than 3 μm in diameter.

  2. REGIONAL DEPOSITION OF COARSE PARTICLES AND VENTILATION DISTRIBUTION IN PATIENTS WITH CYSTIC FIBROSIS

    Science.gov (United States)

    The efficacy of inhaled pharmaceuticals depends, in part, on their site of respiratory deposition. Markedly nonuniform ventilation distribution may occur in persons with obstructive airways diseases and may affect particle deposition. We studied the relationship between regional ...

  3. On the Frequency Distribution of Neutral Particles from Low-Energy Strong Interactions

    Directory of Open Access Journals (Sweden)

    Federico Colecchia

    2017-01-01

    Full Text Available The rejection of the contamination, or background, from low-energy strong interactions at hadron collider experiments is a topic that has received significant attention in the field of particle physics. This article builds on a particle-level view of collision events, in line with recently proposed subtraction methods. While conventional techniques in the field usually concentrate on probability distributions, our study is, to our knowledge, the first attempt at estimating the frequency distribution of background particles across the kinematic space inside individual collision events. In fact, while the probability distribution can generally be estimated given a model of low-energy strong interactions, the corresponding frequency distribution inside a single event typically deviates from the average and cannot be predicted a priori. We present preliminary results in this direction and establish a connection between our technique and the particle weighting methods that have been the subject of recent investigation at the Large Hadron Collider.

  4. Modelling malaria incidence by an autoregressive distributed lag model with spatial component.

    Science.gov (United States)

    Laguna, Francisco; Grillet, María Eugenia; León, José R; Ludeña, Carenne

    2017-08-01

    The influence of climatic variables on the dynamics of human malaria has been widely highlighted. Also, it is known that this mosquito-borne infection varies in space and time. However, when the data is spatially incomplete most popular spatio-temporal methods of analysis cannot be applied directly. In this paper, we develop a two step methodology to model the spatio-temporal dependence of malaria incidence on local rainfall, temperature, and humidity as well as the regional sea surface temperatures (SST) in the northern coast of Venezuela. First, we fit an autoregressive distributed lag model (ARDL) to the weekly data, and then, we adjust a linear separable spacial vectorial autoregressive model (VAR) to the residuals of the ARDL. Finally, the model parameters are tuned using a Markov Chain Monte Carlo (MCMC) procedure derived from the Metropolis-Hastings algorithm. Our results show that the best model to account for the variations of malaria incidence from 2001 to 2008 in 10 endemic Municipalities in North-Eastern Venezuela is a logit model that included the accumulated local precipitation in combination with the local maximum temperature of the preceding month as positive regressors. Additionally, we show that although malaria dynamics is highly heterogeneous in space, a detailed analysis of the estimated spatial parameters in our model yield important insights regarding the joint behavior of the disease incidence across the different counties in our study. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Particle size distribution and gas-particle partitioning of polychlorinated biphenyls in the atmosphere in Beijing, China.

    Science.gov (United States)

    Zhu, Qingqing; Zheng, Minghui; Liu, Guorui; Zhang, Xian; Dong, Shujun; Gao, Lirong; Liang, Yong

    2017-01-01

    Size-fractionated samples of urban particulate matter (PM; ≤1.0, 1.0-2.5, 2.5-10, and >10 μm) and gaseous samples were simultaneously obtained to study the distribution of polychlorinated biphenyls (PCBs) in the atmosphere in Beijing, China. Most recent investigations focused on the analysis of gaseous PCBs, and much less attention has been paid to the occurrence of PCBs among different PM fractions. In the present study, the gas-particle partitioning and size-specific distribution of PCBs in atmosphere were investigated. The total concentrations (gas + particle phase fractions) of Σ 12 dioxin-like PCBs, Σ 7 indicator PCBs, and ΣPCBs were 1.68, 42.1, and 345 pg/m 3 , respectively. PCBs were predominantly in the gas phase (86.8-99.0 % of the total concentrations). The gas-particle partition coefficients (K p ) of PCBs were found to be a significant linear correlated with the subcooled liquid vapor pressures (P L 0 ) (R 2  = 0.83, P gas-particle partitioning of PCBs was affected both by the mechanisms of adsorption and absorption. In addition, the concentrations of PCBs increased as the particle size decreased (>10, 2.5-10, 1.0-2.5, and ≤1.0 μm), with most of the PCBs contained in the fraction of ≤1.0 μm (53.4 % of the total particulate concentrations). Tetra-CBs were the main homolog in the air samples in the gas phase and PM fractions, followed by tri-CBs. This work will contribute to the knowledge of PCBs among different PM fractions and fill the gap of the size distribution of particle-bound dioxin-like PCBs in the air.

  6. Permeability Evolution and Particle Size Distribution of Saturated Crushed Sandstone under Compression

    Directory of Open Access Journals (Sweden)

    Yanlong Chen

    2018-01-01

    Full Text Available In this research, the particle size distribution and permeability of saturated crushed sandstone under variable axial stresses (0, 2, 4, 8, 12, and 16 MPa were studied. X-ray Computed Tomography results revealed that particle crushing is likely to occur considerably as the axial stress is approaching 4 MPa, which results in the change of pore structure greatly. During compression, the particle size distribution satisfies the fractal condition well, and the fractal dimension of particle size distribution is an effective method for describing the particle crushing state of saturated crushed sandstone. When the axial stress increases from 0 MPa to 4 MPa, the fractal dimension of the particle size distribution increases rapidly by over 60% of the total increase (0–16 MPa, and the permeability decreases sharply by about 85% of the total decrease. These results indicate that 4 MPa is a key value in controlling the particle size distribution and the permeability of the saturated crushed sandstone under axial compression. The permeability is influenced by the initial gradation of the specimens, and a larger Talbot exponent corresponds to a larger permeability.

  7. Distribution of latex particles in lung and lymph node tissues of rats and dogs

    International Nuclear Information System (INIS)

    Mueller, H.L; Muggenburg, B.A.; Gillett, N.A.; Guilmette, R.A.

    1988-01-01

    The distribution of fluorescent poly sytrene microspheres in different lung compartments, with differing particle numbers within individual lung and lymph node cells was examined In methacrylate-embedded tissue slices. Rat tissues were analyzed at 1, 7 and 13 days after particle instillation, dog tissues at 7 and 13 days. A much higher fraction of particles was seen in the lung interstitium and in lung-associated lymph nodes in dogs than in rats. Particle concentrations in TBLN cells were generally very low in both species, but were high in free alveolar cells after high particle numbers were instilled, and increased from 1 to 13 days, suggesting that alveolar cells with few particles were cleared faster than those wth high ingested particle numbers. (author)

  8. Number size distribution of fine and ultrafine fume particles from various welding processes.

    Science.gov (United States)

    Brand, Peter; Lenz, Klaus; Reisgen, Uwe; Kraus, Thomas

    2013-04-01

    Studies in the field of environmental epidemiology indicate that for the adverse effect of inhaled particles not only particle mass is crucial but also particle size is. Ultrafine particles with diameters below 100 nm are of special interest since these particles have high surface area to mass ratio and have properties which differ from those of larger particles. In this paper, particle size distributions of various welding and joining techniques were measured close to the welding process using a fast mobility particle sizer (FMPS). It turned out that welding processes with high mass emission rates (manual metal arc welding, metal active gas welding, metal inert gas welding, metal inert gas soldering, and laser welding) show mainly agglomerated particles with diameters above 100 nm and only few particles in the size range below 50 nm (10 to 15%). Welding processes with low mass emission rates (tungsten inert gas welding and resistance spot welding) emit predominantly ultrafine particles with diameters well below 100 nm. This finding can be explained by considerably faster agglomeration processes in welding processes with high mass emission rates. Although mass emission is low for tungsten inert gas welding and resistance spot welding, due to the low particle size of the fume, these processes cannot be labeled as toxicologically irrelevant and should be further investigated.

  9. A new approach to fluid-structure interaction within graphics hardware accelerated smooth particle hydrodynamics considering heterogeneous particle size distribution

    Science.gov (United States)

    Eghtesad, Adnan; Knezevic, Marko

    2017-12-01

    A corrective smooth particle method (CSPM) within smooth particle hydrodynamics (SPH) is used to study the deformation of an aircraft structure under high-velocity water-ditching impact load. The CSPM-SPH method features a new approach for the prediction of two-way fluid-structure interaction coupling. Results indicate that the implementation is well suited for modeling the deformation of structures under high-velocity impact into water as evident from the predicted stress and strain localizations in the aircraft structure as well as the integrity of the impacted interfaces, which show no artificial particle penetrations. To reduce the simulation time, a heterogeneous particle size distribution over a complex three-dimensional geometry is used. The variable particle size is achieved from a finite element mesh with variable element size and, as a result, variable nodal (i.e., SPH particle) spacing. To further accelerate the simulations, the SPH code is ported to a graphics processing unit using the OpenACC standard. The implementation and simulation results are described and discussed in this paper.

  10. Incidence of spinal deformity in adults and its distribution according SRS-Schwab classification

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Amaral Barreto

    2015-06-01

    Full Text Available OBJECTIVE: To evaluate the incidence of spinal deformity in adults, as well as its distribution according the curve type and the occurrence of sagittal modifiers of the SRS-Schwab classification..METHODS: Radiographs in frontal and lateral views of the entire column were performed and radiographic parameters were used to diagnose the vertebral deformity for the classification according to the SRS-Schwab system.RESULTS: We included 302 patients in the study, 236 (78.1% women and 66 (21.9% men. Fifty-six of the participants were diagnosed with ASD, 50 women and 6 men. The incidence of ASD was 18.5% in the total population, ranging from 9.1% in males and 21.2% in females (p=0.04. As to age group, the incidence was 11.9% in patients between 18 and 39 years, 12% between 40 and 59 years and 28.8% in patients with 60 years of age or older, significantly higher in the oldest group (p=0.002. When analyzing the correlation between age and progression of sagittal modifiers, there was no significant difference in the PI-LL and PT modifiers, but there was significant difference of SVA modifier (p=0.008, with a higher age in individuals "++".CONCLUSION: This study presented demographic data on ASD in a Brazilian population sample. There was a higher incidence of ASD in females and individuals aged ≥ 60 years. As for the sagittal modifiers of SRS-Schwab classification, there was a correlation between increasing age and degree of progression of SVA.

  11. Anatomical distribution of peptic ulcer in high incidence gastric cancer area

    Directory of Open Access Journals (Sweden)

    Anuar Alonso Cedeño-Burbano

    2014-12-01

    Full Text Available Background: Peptic ulcer makes reference to the solution of continuity of gastric or duodenal wall beyond muscularis mucosae. Previously, duodenal location was more common than gastric, in a ratio ranging from 2:1 to 4:1. Despite this, after the discovery of the association between peptic ulcer and Helicobacter pylori, relationship between gastric and duodenal ulcer has spread to the equality. However, in areas with high incidence of gastric cancer, peptic ulcer seems to have a different behavior, existing predominance of gastric ulcer. Department of Cauca is have the highest incidence of gastric cancer in Colombia, with an annual rate of 42.5 /100,000 for males and 28.6 / 100,000 for women; however, it is unknown how peptic ulcer anatomically are distributed. Objective: To determine the anatomical distribution of peptic ulcer at endoscopy service of San José University Hospital of Popayán-Cauca, Colombia 2006-2012. Methods: A descriptive cross-sectional study was realized. Database of endoscopy service of San José University Hospital of Popayán was reviewed and reports with diagnosis of peptic ulcer were studied. Data were analyzed using SPSS-15. Results: Gastric ulcer was more common than duodenal ulcer. Gastric ulcer was more common in men (gastric and duodenal ulcer 1:1. In women duodenal ulcer is 1:1. Conclusion: At endoscopy service of San José University Hospital, gastric ulcer is more common than duodenal ulcer, with differences in gender, as in other areas with high incidence of gastric cancer. That fact are suggests in current literature could be related with the presence of stumps of Helicobacter pylori with combined virulence for cancer and ulcer at gastric level seems to be related to the presence in the medium of common virulence strains of Helicobacter pylori for stomach cancer and ulcer gastric, although the current literature is unclear about it, and still needs more validations.

  12. Seasonal cycle and modal structure of particle number size distribution at Dome C, Antarctica

    Directory of Open Access Journals (Sweden)

    E. Järvinen

    2013-08-01

    Full Text Available We studied new particle formation and modal behavior of ultrafine aerosol particles on the high East Antarctic plateau at the Concordia station, Dome C (75°06' S, 123°23' E. Aerosol particle number size distributions were measured in the size range 10–600 nm from 14 December 2007 to 7 November 2009. We used an automatic algorithm for fitting up to three modes to the size distribution data. The total particle number concentration was low with the median of 109 cm−3. There was a clear seasonal cycle in the total particle number and the volume concentrations. The concentrations were at their highest during the austral summer with the median values of 260 cm−3 and 0.086 μm3 cm−3, and at their lowest during the austral winter with corresponding values of 15 cm−3 and 0.009 μm3 cm−3. New particle formation events were determined from the size distribution data. During the measurement period, natural new particle formation was observed on 60 days and for 15 of these days the particle growth rates from 10 to 25 nm in size could be determined. The median particle growth rate during all these events was 2.5 nm h−1 and the median formation rate of 10 nm particles was 0.023 cm−3 s−1. Most of the events were similar to those observed at other continental locations, yet also some variability in event types was observed. Exceptional features in Dome C were the winter events that occurred during dark periods, as well as the events for which the growth could be followed during several consecutive days. We called these latter events slowly growing events. This paper is the first one to analyze long-term size distribution data from Dome C, and also the first paper to show that new particle formation events occur in central Antarctica.

  13. Improved Mathematical Models for Particle-Size Distribution Data

    African Journals Online (AJOL)

    BirukEdimon

    four existing curve fitting models common to geotechnical applications are reviewed and presented first. Definitions of Important Parameters and. Variables. A given soil will be made up of grains of many different sizes and described by the grain size distribution. The main variables are % Clay, %. Silt, % Sand, % of fine and ...

  14. Estimation of particle size distribution of nanoparticles from electrical ...

    Indian Academy of Sciences (India)

    2018-02-02

    Feb 2, 2018 ... Bull. Mater. Sci. (2018) 41:15. Figure 5. Electrically equivalent model circuit of quantum dot. randomly distributed NPs and the background material, Gum acacia [18–22]. The back ground capping media, Gum aca- cia is 97% ionic, 3% electronic conductor [7]. Acacia has a little effect in electronic conduction ...

  15. Distribution functions and thermodynamic functions of many particle systems

    International Nuclear Information System (INIS)

    Isihara, A.; Rosa Junior, S.G.

    1976-01-01

    A method is given of determining and upper bound of the entropy of a classical interacting system. A family of gaussian trial distribution functions is introduced for an electron gas. It was found that the ring diagram energy corresponds to the minimum free energy which the family produces. In contrast to the ring diagram method, the new approach is extremely simple and general [pt

  16. Characterization of road runoff with regard to seasonal variations, particle size distribution and the correlation of fine particles and pollutants.

    Science.gov (United States)

    Hilliges, R; Endres, M; Tiffert, A; Brenner, E; Marks, T

    2017-03-01

    Urban runoff is known to transport a significant pollutant load consisting of e.g. heavy metals, salts and hydrocarbons. Interactions between solid and dissolved compounds, proper understanding of particle size distribution, dissolved pollutant fractions and seasonal variations is crucial for the selection and development of appropriate road runoff treatment devices. Road runoff at an arterial road in Augsburg, Germany, has been studied for 3.5 years. A strong seasonal variation was observed, with increased heavy metal concentrations with doubled and tripled median concentrations for heavy metals during the cold season. Correlation analysis showed that de-icing salt is not the only factor responsible for increased pollutant concentrations in winter. During the cold period, the fraction of dissolved metals was lower compared to the warm season. In road dust, the highest metal concentrations were measured for fine particles. Metals in road runoff were found to show a significant correlation to fine particles SS63 (removal rates.

  17. Prediction of the filtrate particle size distribution from the pore size distribution in membrane filtration: Numerical correlations from computer simulations

    Science.gov (United States)

    Marrufo-Hernández, Norma Alejandra; Hernández-Guerrero, Maribel; Nápoles-Duarte, José Manuel; Palomares-Báez, Juan Pedro; Chávez-Rojo, Marco Antonio

    2018-03-01

    We present a computational model that describes the diffusion of a hard spheres colloidal fluid through a membrane. The membrane matrix is modeled as a series of flat parallel planes with circular pores of different sizes and random spatial distribution. This model was employed to determine how the size distribution of the colloidal filtrate depends on the size distributions of both, the particles in the feed and the pores of the membrane, as well as to describe the filtration kinetics. A Brownian dynamics simulation study considering normal distributions was developed in order to determine empirical correlations between the parameters that characterize these distributions. The model can also be extended to other distributions such as log-normal. This study could, therefore, facilitate the selection of membranes for industrial or scientific filtration processes once the size distribution of the feed is known and the expected characteristics in the filtrate have been defined.

  18. Advanced analysis of polymer emulsions: Particle size and particle size distribution by field-flow fractionation and dynamic light scattering.

    Science.gov (United States)

    Makan, Ashwell C; Spallek, Markus J; du Toit, Madeleine; Klein, Thorsten; Pasch, Harald

    2016-04-15

    Field flow fractionation (FFF) is an advanced fractionation technique for the analyses of very sensitive particles. In this study, different FFF techniques were used for the fractionation and analysis of polymer emulsions/latexes. As model systems, a pure acrylic emulsion and emulsions containing titanium dioxide were prepared and analyzed. An acrylic emulsion polymerization was conducted, continuously sampled from the reactor and subsequently analyzed to determine the particle size, radius of gyration in specific, of the latex particles throughout the polymerization reaction. Asymmetrical flow field-flow fractionation (AF4) and sedimentation field-flow fractionation (SdFFF), coupled to a multidetector system, multi-angle laser light scattering (MALLS), ultraviolet (UV) and refractive index (RI), respectively, were used to investigate the evolution of particle sizes and particle size distributions (PSDs) as the polymerization progressed. The obtained particle sizes were compared against batch-mode dynamic light scattering (DLS). Results indicated differences between AF4 and DLS results due to DLS taking hydration layers into account, whereas both AF4 and SdFFF were coupled to MALLS detection, hence not taking the hydration layer into account for size determination. SdFFF has additional separation capabilities with a much higher resolution compared to AF4. The calculated radii values were 5 nm larger for SdFFF measurements for each analyzed sample against the corresponding AF4 values. Additionally a low particle size shoulder was observed for SdFFF indicating bimodality in the reactor very early during the polymerization reaction. Furthermore, different emulsions were mixed with inorganic species used as additives in cosmetics and coatings such as TiO2. These complex mixtures of species were analyzed to investigate the retention and particle interaction behavior under different AF4 experimental conditions, such as the mobile phase. The AF4 system was coupled online

  19. [Size distributions of organic carbon (OC) and elemental carbon (EC) in Shanghai atmospheric particles].

    Science.gov (United States)

    Wang, Guang-Hua; Wei, Nan-Nan; Liu, Wei; Lin, Jun; Fan, Xue-Bo; Yao, Jian; Geng, Yan-Hong; Li, Yu-Lan; Li, Yan

    2010-09-01

    Size distributions of organic carbon (OC), elemental carbon (EC) and secondary organic carbon (SOC) in atmospheric particles with size range from 7.20 microm, collected in Jiading District, Shanghai were determined. For estimating size distribution of SOC in these atmospheric particles, a method of determining (OC/EC)(pri) in atmospheric particles with different sizes was discussed and developed, with which SOC was estimated. According to the correlation between OC and EC, main sources of the particles were also estimated roughly. The size distributions of OC and SOC showed a bi-modal with peaks in the particles with size of 3.0 microm, respectively. EC showed both of a bi-modal and tri-modal. Compared with OC, EC was preferably enriched in particles with size of 3.00 microm) accounted for 41.4% and 43.5% of corresponding OC. Size distributions of OC, EC and SOC showed time-dependence. The correlation between OC and EC showed that the main contribution to atmospheric particles in Jiading District derived from light petrol vehicles exhaust.

  20. Pre-equilibrium particles emission: impact parameter and incident energy influence

    International Nuclear Information System (INIS)

    Peter, J.; Cussol, D.; Bizard, G.; Brou, R.; Louvel, M.; Patry, J.P.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.; Motobayashi, T.; Cassagnou, Y.; Legrain, R.; Hagel, K.; Jin, G.M.; Motobayashi, T.

    1990-01-01

    Charged particles and fragments emitted in reactions between 40 Ar at 45 and 65 MeV/u and an 27 Al target have been detected in a geometry close to 4 π in the center of mass. A new global variable, the average parallel velocity, has been used to sort the events as a function of the impact parameter value. For particles with Z = 1 and 2, a pre-equilibrium component is present. Its multiplicity increases strongly when the impact parameter value decreases, and reaches 7 in head-on reactions [fr

  1. Development of laboratory and process sensors to monitor particle size distribution of industrial slurries

    Energy Technology Data Exchange (ETDEWEB)

    Pendse, H.P.

    1992-10-01

    In this paper we present a novel measurement technique for monitoring particle size distributions of industrial colloidal slurries based on ultrasonic spectroscopy and mathematical deconvolution. An on-line sensor prototype has been developed and tested extensively in laboratory and production settings using mineral pigment slurries. Evaluation to date shows that the sensor is capable of providing particle size distributions, without any assumptions regarding their functional form, over diameters ranging from 0.1 to 100 micrometers in slurries with particle concentrations of 10 to 50 volume percents. The newly developed on-line sensor allows one to obtain particle size distributions of commonly encountered inorganic pigment slurries under industrial processing conditions without dilution.

  2. Soot Particle Size Distribution Functions in a Turbulent Non-Premixed Ethylene-Nitrogen Flame

    KAUST Repository

    Boyette, Wesley

    2017-02-21

    A scanning mobility particle sizer with a nano differential mobility analyzer was used to measure nanoparticle size distribution functions in a turbulent non-premixed flame. The burner utilizes a premixed pilot flame which anchors a C2H4/N2 (35/65) central jet with ReD = 20,000. Nanoparticles in the flame were sampled through a N2-filled tube with a 500- μm orifice. Previous studies have shown that insufficient dilution of the nanoparticles can lead to coagulation in the sampling line and skewed particle size distribution functions. A system of mass flow controllers and valves were used to vary the dilution ratio. Single-stage and two-stage dilution systems were investigated. A parametric study on the effect of the dilution ratio on the observed particle size distribution function indicates that particle coagulation in the sampling line can be eliminated using a two-stage dilution process. Carbonaceous nanoparticle (soot) concentration particle size distribution functions along the flame centerline at multiple heights in the flame are presented. The resulting distributions reveal a pattern of increasing mean particle diameters as the distance from the nozzle along the centerline increases.

  3. Multimodal particle size distributions emitted from HFA-134a solution pressurized metered-dose inhalers.

    Science.gov (United States)

    Smyth, Hugh D C; Hickey, Anthony J

    2003-01-01

    The purpose of this research was to investigate the measurement and in vitro delivery implications of multimodal distributions, occurring near or in the respirable range, emitted from pressurized metered-dose inhalers (pMDIs). Particle size distributions of solution pMDIs containing hydrofluoroalkane-134a (HFA-134a) and ethanol were evaluated using 2 complementary particle-sizing methods: laser diffraction (LD) and cascade impaction (CI). Solution pMDIs were formulated from mixtures of HFA-134a (50%-97.5% wt/wt) and ethanol. A range of propellant concentrations was selected for a range of vapor pressures. The fluorescent probe, Rhodamine B, was included for chemical analysis. The complementary nature of LD and CI allowed identification of 2 dominant particle size modes at 1 and 10 micro m or greater. Increasing propellant concentrations resulted in increases in the proportion of the size distributions at the 1- micro m mode and also reduced the particle size of the larger droplet population. Despite significant spatial differences and time scales of measurement between the particle-sizing techniques, the fine particle fractions obtained from LD and CI were practically identical. This was consistent with LD experiments, which showed that particle sizes did not decrease with increasing measurement distance, and may be explained by the absence of significant evaporation/disintegration of larger droplets. The fine particle fractions (FPFs) emitted from HFA-134a/ethanol solution pMDI can be predicted on the basis of formulation parameters and is independent of measurement technique. These results highlight the importance of presenting particle size distribution data from complementary particle size techniques.

  4. Size distribution and hygroscopic properties of aerosol particles from dry-season biomass burning in Amazonia

    Directory of Open Access Journals (Sweden)

    J. Rissler

    2006-01-01

    Full Text Available Aerosol particle number size distributions and hygroscopic properties were measured at a pasture site in the southwestern Amazon region (Rondonia. The measurements were performed 11 September-14 November 2002 as part of LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia - SMOke aerosols, Clouds, rainfall and Climate, and cover the later part of the dry season (with heavy biomass burning, a transition period, and the onset of the wet period. Particle number size distributions were measured with a DMPS (Differential Mobility Particle Sizer, 3-850nm and an APS (Aerodynamic Particle Sizer, extending the distributions up to 3.3 µm in diameter. An H-TDMA (Hygroscopic Tandem Differential Mobility Analyzer measured the hygroscopic diameter growth factors (Gf at 90% relative humidity (RH, for particles with dry diameters (dp between 20-440 nm, and at several occasions RH scans (30-90% RH were performed for 165nm particles. These data provide the most extensive characterization of Amazonian biomass burning aerosol, with respect to particle number size distributions and hygroscopic properties, presented until now. The evolution of the convective boundary layer over the course of the day causes a distinct diel variation in the aerosol physical properties, which was used to get information about the properties of the aerosol at higher altitudes. The number size distributions averaged over the three defined time periods showed three modes; a nucleation mode with geometrical median diameters (GMD of ~12 nm, an Aitken mode (GMD=61-92 nm and an accumulation mode (GMD=128-190 nm. The two larger modes were shifted towards larger GMD with increasing influence from biomass burning. The hygroscopic growth at 90% RH revealed a somewhat external mixture with two groups of particles; here denoted nearly hydrophobic (Gf~1.09 for 100 nm particles and moderately hygroscopic (Gf~1.26. While the hygroscopic growth factors were surprisingly similar over the

  5. Effects of oil dispersants on settling of marine sediment particles and particle-facilitated distribution and transport of oil components.

    Science.gov (United States)

    Cai, Zhengqing; Fu, Jie; Liu, Wen; Fu, Kunming; O'Reilly, S E; Zhao, Dongye

    2017-01-15

    This work investigated effects of three model oil dispersants (Corexit EC9527A, Corexit EC9500A and SPC1000) on settling of fine sediment particles and particle-facilitated distribution and transport of oil components in sediment-seawater systems. All three dispersants enhanced settling of sediment particles. The nonionic surfactants (Tween 80 and Tween 85) play key roles in promoting particle aggregation. Yet, the effects varied with environmental factors (pH, salinity, DOM, and temperature). Strongest dispersant effect was observed at neutral or alkaline pH and in salinity range of 0-3.5wt%. The presence of water accommodated oil and dispersed oil accelerated settling of the particles. Total petroleum hydrocarbons in the sediment phase were increased from 6.9% to 90.1% in the presence of Corexit EC9527A, and from 11.4% to 86.7% for PAHs. The information is useful for understanding roles of oil dispersants in formation of oil-sediment aggregates and in sediment-facilitated transport of oil and PAHs in marine eco-systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Size distribution of mineral aerosol: using light-scattering models in laser particle sizing.

    NARCIS (Netherlands)

    Veihelmann, B.; Konert, M.; van der Zande, W.J.

    2006-01-01

    The size distribution of semitransparent irregularly shaped mineral dust aerosol samples is determined using a commonly used laser particle-sizing technique. The size distribution is derived from intensity measurements of singly scattered light at various scattering angles close to the

  7. Size distribution of mineral aerosol: using light-scattering models in laser particle sizing

    NARCIS (Netherlands)

    Veihelmann, B.; Konert, M.; Zande, W.J. van der

    2006-01-01

    The size distribution of semitransparent irregularly shaped mineral dust aerosol,samples is determined using a commonly used laser particle-sizing technique. The size distribution is derived from intensity measurements of singly scattered light at various scattering angles close to the

  8. Scaled momentum distributions of charged particles in dijet photoproduction at HERA

    NARCIS (Netherlands)

    Chekanov, S.; Derrick, M.; Magill, S.; Musgrave, B.; Nicholass, D.; Ropond, J.; Yoshida, R.; Mattingly, M. C. K.; Antonioli, P.; Bari, G.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cindolo, F.; Corradi, M.; Iacobucci, G.; Margotti, A.; Nania, R.; Polini, A.; Antonelli, S.; Basile, M.; Bindi, M.; Cifarelli, L.; Contin, A.; De Pasquale, S.; Sartorelli, G.; Zichichi, A.; Bartsch, D.; Brock, I.; Hartmann, H.; Hilger, E.; Jakob, H. -P.; Juengst, M.; Nuncio-Quiroz, A. E.; Samson, U.; Schoenberg, V.; Shehzadi, R.; Wlasenko, M.; Brook, N. H.; Heath, G. P.; Kaur, M.; Kaur, P.; Singh, I.; Capua, M.; Fazio, S.; Mastroberardino, A.; Schioppa, M.; Susinno, G.; Tassi, E.; Kim, J. Y.; Ibrahim, Z. A.; Idris, F. Mohamad; Kamaluddin, B.; Abdullah, W. A. T. Wan; Ning, Y.; Ren, Z.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Galas, A.; Olkiewicz, K.; Pawlik, B.; Stopa, P.; Zawiejski, L.; Adamczyk, L.; Bold, T.; Grabowska-Bold, I.; Kisielewska, D.; Lukasik, J.; Przybycien, M.; Suszycki, L.; Kotanski, A.; Slominski, W.; Behnke, O.; Behr, J.; Behrens, U.; Blohm, C.; Borras, K.; Ciesielski, R.; Coppola, N.; Geiser, A.; Goettlicher, P.; Grebenyuk, J.; Gregor, I.; Haas, T.; Hain, W.; Huettmann, A.; Januschek, F.; Kahle, B.; Katkov, I. I.; Klein, U.; Koetz, U.; Kowalski, H.; Lisovyi, M.; Lobodizinska, E.; Loehr, B.; Mankel, R.; Melzer-Pellmann, I. -A.; Miglioranzi, S.; Montanari, A.; Namsoo, T.; Notz, D.; Parenti, A.; Roloff, P.; Rubinsky, I.; Schneekloth, U.; Spiridonov, A.; Szuba, D.; Szuba, J.; Theedt, T.; Tomaszewska, J.; Wolf, G.; Wrona, K.; Yaguees-Molina, A. G.; Youngman, C.; Zeuner, W.; Drugakov, V.; Lohmann, W.; Schlenstedt, S.; Barbagli, G.; Gallo, E.; Pelfer, P. G.; Bamberger, A.; Dobur, D.; Karstens, F.; Vlasov, N. N.; Bussey, P. J.; Doyle, A. T.; Forrest, M.; Saxon, D. H.; Skillicorn, I. O.; Gialas, I.; Papageorgiu, K.; Holm, U.; Klanner, R.; Lohrmann, E.; Perrey, H.; Schleper, P.; Schoerner-Sadenius, T.; Sztuk, J.; Stadie, H.; Turcato, M.; Foudas, C.; Fry, C.; Long, K. R.; Tapper, A. D.; Matsumoto, T.; Nagano, K.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Barakbaev, A. N.; Boos, E. G.; Pokrovskiy, N. S.; Zhautykov, B. O.; Aushev, V.; Bachynska, O.; Borodin, M.; Kadenko, I.; Kuprash, O.; Libov, V.; Lontkovskyi, D.; Makarenko, I.; Sorokin, Iu.; Verbytskyi, A.; Volynets, O.; Zolko, M.; Son, D.; de Favereau, J.; Piotrzkowski, K.; Barreiro, F.; Glasman, C.; Jimenez, M.; del Peso, J.; Ron, E.; Terron, J.; Uribe-Estrada, C.; Corriveau, F.; Schwartz, J.; Tsurugai, T.; Antonov, A.; Dolgoshein, B. A.; Gladkov, D.; Sosnovtsev, V.; Stifutkin, A.; Suchkov, S.; Dementiev, R. K.; Ermolov, P. F.; Gladilin, L. K.; Golubkov, Yu. A.; Khein, L. A.; Korzhavina, I. A.; Kuzmin, V. A.; Levchenko, B. B.; Lukina, O. Yu.; Proskuryakov, A. S.; Shcheglova, L. M.; Zotkin, D. S.; Abt, I.; Caldwell, A.; Kollar, D.; Reisert, B.; Schmidke, W. B.; Grigorescu, G.; Keramidas, A.; Koffemann, E.; Kooijman, P.; Pellegrino, A.; Tiecke, H.; Vazquez, M.; Bruemmer, N.; Bylsma, B.; Durkin, L. S.; Lee, A.; Ling, T. Y.; Allfrey, P. D.; Bell, M. A.; Cooper-Sarkar, A. M.; Devenish, R. C. E.; Ferrando, J.; Foster, B.; Gwenlan, C.; Horton, K.; Oliver, K.; Robertson, A.; Walczak, R.; Bertolin, A.; Dal Corso, F.; Dusini, S.; Longhin, A.; Stanco, L.; Brugnera, R.; Carlin, R.; Garfagnini, A.; Limentani, S.; Oh, B. Y.; Raval, A.; Whitmore, J. J.; Iga, Y.; D'Agostini, G.; Marimi, G.; Nigro, A.; Cole, J. E.; Hart, J. C.; Abramowicz, H.; Ingbir, R.; Kananov, S.; Stern, A.; Kuze, M.; Maeda, J.; Hori, R.; Kagawa, S.; Okazaki, N.; Tawara, T.; Hamatsu, R.; Kaji, H.; Kitamura, S.; Ota, O.; Ri, Y. D.; Costa, M.; Ferrero, M. I.; Monaco, V.; Sacchi, R.; Sola, V.; Solano, A.; Arneodo, M.; Ruspa, M.; Fourletov, S.; Stewart, T. P.; Boutle, S. K.; Butterworth, J. M.; Jones, T. W.; Loizides, J. H.; Wing, M.; Brzozowska, B.; Ciborowski, J.; Grzelak, G.; Kulinski, P.; Luzniak, P.; Malka, J.; Nowak, R. J.; Pawlak, J. M.; Perlanski, W.; Zarnecki, A. F.; Adamus, M.; Plucinski, P.; Tymieniecka, T.; Eisenberg, Y.; Hochman, D.; Karshon, U.; Brownson, E.; Reeder, D. D.; Savin, A. A.; Smith, W. H.; Wolfe, H.; Bhadra, S.; Catterall, C. D.; Hartner, G.; Menary, S.; Noor, U.; Standage, J.; Whyte, J.

    The scaled momentum distributions of charged particles in jets have been measured for dijet photoproduction with the ZEUS detector at HERA using an integrated luminosity of 359 pl(-1). The distributions are compared to predictions based on pertubative QCD carried out in the framework of the modified

  9. Fuzzy Adaptive Particle Swarm Optimization for Power Loss Minimisation in Distribution Systems Using Optimal Load Response

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte

    2014-01-01

    power loss minimization in distribution systems. In this paper, a new method to achieve power loss minimization in distribution systems by using a price signal to guide the demand side management is proposed. A fuzzy adaptive particle swarm optimization (FAPSO) is used as a tool for the power loss...

  10. Variations in Tropospheric Submicron Particle Size Distributions Across the European Continent 2008–2009

    Czech Academy of Sciences Publication Activity Database

    Beddows, D.C.S.; Dall’Osto, M.; Harrison, R.M.; Kulmala, M.; Asmi, A.; Wiedensohler, A.; Laj, P.; Fjaeraa, A.M.; Sellegri, K.; Birmili, W.; Bukowiecki, N.; Weingartner, E.; Baltensperger, U.; Ždímal, Vladimír; Zíková, Naděžda; Putaud, J.-P.; Marinoni, A.; Tunved, P.; Hansson, H.-C.; Feibig, M.; Kivekäs, N.; Swietlicki, E.; Lihavainen, H.; Asmi, E.; Ulevicius, V.; Aalto, P.P.; Mihalopoulos, N.; Kalivitis, N.; Kalapov, I.; Kiss, G.; de Leeuw, G.; Henzing, B.; O'Dowd, C.; Jennings, S.G.; Flentje, H.; Meinhardt, F.; Ries, L.; Denier van der Gon19, H.A.C.; Visschedijk, A.J.H.; Swietlicki, E.

    2014-01-01

    Roč. 14, č. 8 (2014), s. 4327-4348 ISSN 1680-7316 EU Projects: European Commission(XE) 36833 - EUCAARI; European Commission(XE) 26140 - EUSAAR Institutional support: RVO:67985858 Keywords : particle size distribution * clusters * aerosol size distribution Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.053, year: 2014

  11. Seasonal differences of the atmospheric particle size distribution in a metropolitan area in Japan.

    Science.gov (United States)

    Fujitani, Yuji; Kumar, Prashant; Tamura, Kenji; Fushimi, Akihiro; Hasegawa, Shuich; Takahashi, Katsuyuki; Tanabe, Kiyoshi; Kobayashi, Shinji; Hirano, Seishiro

    2012-10-15

    We compared the effect of ambient temperature observed in two different seasons on the size distribution and particle number concentration (PNC) as a function of distance (up to ~250 m) from a major traffic road (25% of the vehicles are heavy-duty diesel vehicles). The modal particle diameter was found between 10 and 30 nm at the roadside in the winter. However, there was no peak for this size range in the summer, even at the roadside. Ambient temperature affects both the atmospheric dilution ratio (DR) and the evaporation rate of particles, thus it affects the decay rate of PNC. We corrected the DR effect in order to focus on the effect of particle evaporation on PNC decay. The decay rate of PNC with DR was found to depend on the season and particle diameter. During the winter, the decay rate for smaller particles (30 nm in diameter, the decay rate was nearly the same during both seasons. This distinction between particles less than or greater than 30 nm in diameter reflects differences in particle volatility properties. Mass-transfer theory was used to estimate evaporation rates of C20-C36 n-alkane particles, which are the major n-alkanes in diesel exhaust particles. The C20-C28 n-alkanes of 30-nm particles completely evaporate at 31.2 °C (summer), and their lifetime is shorter than the transport time of air masses in our region of interest. Absence of the peak at 10-30 nm and the low decay rate of PNC us to conclude that these particles show distinctly different spatial distributions depending on the season. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Mathematical modeling of pigment dispersion taking into account the full agglomerate particle size distribution

    DEFF Research Database (Denmark)

    Kiil, Søren

    2017-01-01

    . The only adjustable parameter used was an apparent rate constant for the linear agglomerate erosion rate. Model simulations, at selected values of time, for the full agglomerate particle size distribution were in good qualitative agreement with the measured values. A quantitative match of the experimental...... particle size distribution was simulated. Data from two previous experimental investigations were used for model validation. The first concerns two different yellow organic pigments dispersed in nitrocellulose/ethanol vehicles in a ball mill and the second a red organic pigment dispersed in a solvent...... particle size distributions could be obtained using time-dependent fragment distributions, but this resulted in a very slight improvement in the simulated transient mean diameter only. The model provides a mechanistic understanding of the agglomerate breakage process that can be used, e...

  13. Description of charged particle pseudorapidity distributions in Pb+Pb collisions with Tsallis thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Y. [Hangzhou Dianzi University, School of Information Engineering, Hangzhou (China); Zheng, H. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Zhu, L.L. [Sichuan University, College of Physical Science and Technology, Chengdu (China); Bonasera, A. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Texas A and M University, Cyclotron Institute, College Station, TX (United States)

    2017-10-15

    The centrality dependence of pseudorapidity distributions for charged particles produced in Au+Au collisions at √(s{sub NN}) = 130 GeV and 200 GeV at RHIC, and in Pb+Pb collisions at √(s{sub NN}) = 2.76 TeV at LHC are investigated in the fireball model, assuming that the rapidity axis is populated with fireballs following one distribution function. We assume that the particles in the fireball fulfill the Tsallis distribution. The theoretical results are compared with the experimental measurements and a good agreement is found. Using these results, the pseudorapidity distributions of charged particles produced in Pb+Pb central collisions at √(s{sub NN}) = 5.02 TeV and 10 TeV are predicted. (orig.)

  14. Particle simulation on a distributed memory highly parallel processor

    International Nuclear Information System (INIS)

    Sato, Hiroyuki; Ikesaka, Morio

    1990-01-01

    This paper describes parallel molecular dynamics simulation of atoms governed by local force interaction. The space in the model is divided into cubic subspaces and mapped to the processor array of the CAP-256, a distributed memory, highly parallel processor developed at Fujitsu Labs. We developed a new technique to avoid redundant calculation of forces between atoms in different processors. Experiments showed the communication overhead was less than 5%, and the idle time due to load imbalance was less than 11% for two model problems which contain 11,532 and 46,128 argon atoms. From the software simulation, the CAP-II which is under development is estimated to be about 45 times faster than CAP-256 and will be able to run the same problem about 40 times faster than Fujitsu's M-380 mainframe when 256 processors are used. (author)

  15. Modeling particle transport and discoloration risk in drinking water distribution networks

    Science.gov (United States)

    van Summeren, Joost; Blokker, Mirjam

    2017-10-01

    Discoloration of drinking water is a worldwide phenomenon caused by accumulation and subsequent remobilization of particulate matter in drinking water distribution systems (DWDSs). It contributes a substantial fraction of customer complaints to water utilities. Accurate discoloration risk predictions could improve system operation by allowing for more effective programs on cleaning and prevention actions and field measurements, but are challenged by incomplete understanding on the origins and properties of particles and a complex and not fully understood interplay of processes in distribution networks. In this paper, we assess and describe relevant hydraulic processes that govern particle transport in turbulent pipe flow, including gravitational settling, bed-load transport, and particle entrainment into suspension. We assess which transport mechanisms are dominant for a range of bulk flow velocities, particle diameters, and particle mass densities, which includes common conditions for DWDSs in the Netherlands, the UK, and Australia. Our analysis shows that the theoretically predicted particle settling velocity and threshold shear stresses for incipient particle motion are in the same range as, but more variable than, previous estimates from lab experiments, field measurements, and modeling. The presented material will be used in the future development of a numerical modeling tool to determine and predict the spatial distribution of particulate material and discoloration risk in DWDSs. Our approach is aimed at understanding specific causalities and processes, which can complement data-driven approaches.

  16. The influence of attrition and cyclone performance on the particle size distribution in a CFB system

    Energy Technology Data Exchange (ETDEWEB)

    Cornelis Klett; Ernst-Ulrich Hartge; Joachim Werther [Technical University Hamburg-Harburg, Hamburg (Germany)

    2005-07-01

    Based on previous investigations in the authors' group on attrition mechanisms in fluidized bed systems a model has been developed which allows the simulation of the influences of particle attrition and cyclone performance on the time-dependent development of the particle size distribution in a circulating fluidized bed system consisting of a riser, a cyclone and a solids return leg. In an extension of previous work it was now possible to include the effect of the residence time of the particles in the system. The model takes account of the fact that fresh particles have a higher attrition rate than particles which have stayed for some time already in the system. The model is able to describe the dynamic adjustment of the particle size distribution in a given system. The model was validated with coal combustion experiments in a pilot-scale CFB combustion unit. Ash samples were taken from the bottom part of the riser and compared with the theoretical predictions. The model was used in simulation runs to study the effects of changes in the operating conditions on the steady-state solids particle size distribution and solids mass fluxes. 9 refs., 9 figs., 2 tabs.

  17. Stationary distribution of a stochastic SIS epidemic model with double diseases and the Beddington-DeAngelis incidence

    Science.gov (United States)

    Liu, Qun; Jiang, Daqing

    2017-08-01

    In this paper, a stochastic Susceptible-Infected-Susceptible (SIS) epidemic model with double diseases and the Beddington-DeAngelis incidence is proposed and studied. Sufficient conditions for the existence of an ergodic stationary distribution of the positive solutions to the model are obtained via the Lyapunov function method. The existence of stationary distribution implies stochastic stability to some extent.

  18. Stationary distribution of a stochastic SIS epidemic model with double diseases and the Beddington-DeAngelis incidence.

    Science.gov (United States)

    Liu, Qun; Jiang, Daqing

    2017-08-01

    In this paper, a stochastic Susceptible-Infected-Susceptible (SIS) epidemic model with double diseases and the Beddington-DeAngelis incidence is proposed and studied. Sufficient conditions for the existence of an ergodic stationary distribution of the positive solutions to the model are obtained via the Lyapunov function method. The existence of stationary distribution implies stochastic stability to some extent.

  19. Effect of particle size distribution on the rheology of oil-coal slurries

    Energy Technology Data Exchange (ETDEWEB)

    Hao, L.; Wang, Y.; Xiong, C. [China University of Mining and Technology, Beijing (China)

    2007-02-15

    The rheological behaviour of Shenhua coal-oil slurry was studied as a function of solids concentration, particle size and size distribution. At a certain particle size distribution the apparent viscosity of coal slurry increases with the increase of solid concentration. Coal slurries were found to exhibit a wide spectrum of flow behaviour ranging from Newtonian at low concentrations to shear-thinning and pseudoplastic with a yield stress at higher concentrations. By adding a narrow-sized coarse coal fraction to the finer coal slurry, a flow characteristics optimum coarse-to-fine particle ratio of 40:60 exists at which the slurry is Newtonian. The significant improvement in the rheological behavior with changing the particle size distribution may be explained in terms of spatial rearrangement of the particles and apparent dilution effect. The results indicate that, with a careful control of the particle size distribution, it is possible to prepare an optimum oil-coal slurry which has a low viscosity but with high solids loadings. 10 refs., 4 figs., 3 tabs.

  20. The Incidence and Topographic Distribution of Sutures Including Wormian Bones in Human Skulls.

    Science.gov (United States)

    Cirpan, Sibel; Aksu, Funda; Mas, Nuket

    2015-07-01

    The Wormian Bones are accessory bones located within the cranial sutures and fontanelles. The present article examines the incidence of Wormian Bones and compares the number and topographic distribution between the sutures including Wormian Bones in skulls of West Anatolian Population. One hundred fifty crania were examined. The parameters evaluated in the present study were as follows: the rate of skulls including Wormian Bones; the topographic distribution and frequencies of the sutures including Wormian Bones; the number of these sutures for each skull; the name and number of sutures that were bilaterally and symmetrically located on the right and left side of skull (paired sutures) and which coincidentally had Wormian Bones for each skull; the differences of frequencies between the paired sutures including Wormian Bones. The rate of skulls including Wormian Bones was determined as 59.3%. The maximum and minimum numbers of sutures, including Wormian Bones, were 6 in 1 skull and 1 in each of 30 skulls, respectively. The maximum and minimum rates of sutures that had Wormian Bones were found in left lambdoid 40.7% and right occipitomastoid 1.3% sutures, respectively. There was only a significant difference between the rate of right and left squamous sutures (P = 0.04). Forty-five skulls were including 55 pairs of bilaterally and symmetrically located sutures that coincidentally had Wormian Bones in each pair. Each of 35 skulls had 1 pair of sutures including Wormian Bones and each of 10 skulls had 2 pairs. In the present study, the rate of Wormian Bones was determined as 59.3% in West Anatolian Population. This incidence rate is considerably lower than the other reports, and it may be as a result of racial variations. These divergent bones were more frequently found in left lambdoid sutures (40.7%) and less frequently in right occipitomastoid sutures (1.3%). This study may guide the investigators dealing with the neurosurgery, orthopedy, radiology, anatomy, and

  1. Influences of magnetic particle-particle interactions on orientational distributions and rheological properties for a colloidal dispersion composed of rod-like particle with a magnetic moment normal to the particle axis

    Science.gov (United States)

    Hayasaka, Ryo; Aoshima, Masayuki; Satoh, Akira

    We have investigated mainly the influences of magnetic particle-particle interactions on the orientational distribution and viscosity of a semi-dense dispersion, which is composed of rod-like particles with a magnetic moment magnetized normal to the particle axis. In addition, the influences of the magnetic field strength, shear rate, and random forces on the orientational distribution and rheological properties have been clarified. The mean field approximation has been applied to take into account magnetic interactions between rod-like particles. The basic equation of the orientational distribution function has been derived from the balance of torques and solved by the numerical analysis method. The results obtained here are summarized as follows. For a strong magnetic field, the rotational motion of the rod-like particle is restricted in a plane normal to the shearing plane since the magnetic moment of the particle is restricted in the magnetic field direction. Under circumstances of a very strong magnetic interaction between particles, the magnetic moment is strongly restricted in the magnetic field direction, so that the particle has a tendency to incline in the flow direction with the magnetic moment pointing to the magnetic field direction. For a strong shear flow, a directional characteristic of rod-like particles is enhanced, and this leads to a more significant one-peak-type distribution of the orientational distribution function. Magnetic interactions between particles do not contribute to the increase in the viscosity because the mean-field vector has only a component along the magnetic field direction.

  2. Analytical transform techniques to retrieve non-spherical particle size distribution

    International Nuclear Information System (INIS)

    Zhao, Jian-Qi; Li, Jiangnan

    2013-01-01

    The measurement of particle size distribution (PSD) from the extinction spectra is a challenging problem, especially for non-spherical particles. In this work, the analytical transform techniques are developed to retrieve PSD from the measured scattering data for a variety of shapes of non-spherical particle including spheroids, cuboids, triangular prisms, hexagonal prisms and elliptical cylinders. In the retrieve calculation, all particles have aligned orientations and their extinction cross sections can be adequately calculated by using the anomalous diffraction theory (ADT). It is shown that for each type of the considered non-spherical particles, there exists an ADT transform pair between the size distribution and the extinction spectrum. The inverse formula of PSD from the related ADT transform is therefore established. This result provides a new approach to the solution of the inversion problem and has the potential to be used in finding solutions for more complicated particle shapes. It is found that the solution of inverse scattering for absorbing particles can be simplified to a particular solution in which the character of absorption becomes no longer present. For spheroids, triangular prisms, and elliptical cylinders, the retrieved PSD and the corresponding true PSD always belong to one family of function, due to the scaling relation. Therefore an improper choice of inversion parameters does not significantly affect the type of mode of PSD in a retrieval process. -- Highlights: •Analytical schemes for inversion of non-spherical particle size distribution. •Intuitive inverse formulas and novel ADT transform fairs for non-spherical particles. •Useful scaling relations in retrievals for non-spherical particles

  3. Particle size distribution in ambient air of Delhi and its statistical analysis.

    Science.gov (United States)

    Chelani, A B; Gajghate, D G; Chalapatirao, C V; Devotta, S

    2010-07-01

    Particle size distribution in ambient air has been studied in an urban city, Delhi. Different activity sites namely; kerbside, industrial and residential were selected for the study. The statistical analysis was carried out to study the frequency distribution and sources of different particle size fractions. The dominance of coarse particles attributed to local activities was observed at all the sites. It was observed that at kerbside sites, up to 52% of the particles were lower respiratory tract and up to 47% of the particles were upper respiratory tract particles. At residential and industrial sites, up to 40% and 31% were lower and upper respiratory tract particles, respectively. Factor analysis results indicated auto-exhaust as the dominant source of particulate matter at two of the kerbside sites. Resuspended dust was dominant at remaining two kerbside and residential sites. It was inferred using geometric standard deviation of particle size fractions that these were from different sources at residential and industrial site and from similar sources at three of the kerbside sites.

  4. Radial transport processes as a precursor to particle deposition in drinking water distribution systems.

    Science.gov (United States)

    van Thienen, P; Vreeburg, J H G; Blokker, E J M

    2011-02-01

    Various particle transport mechanisms play a role in the build-up of discoloration potential in drinking water distribution networks. In order to enhance our understanding of and ability to predict this build-up, it is essential to recognize and understand their role. Gravitational settling with drag has primarily been considered in this context. However, since flow in water distribution pipes is nearly always in the turbulent regime, turbulent processes should be considered also. In addition to these, single particle effects and forces may affect radial particle transport. In this work, we present an application of a previously published turbulent particle deposition theory to conditions relevant for drinking water distribution systems. We predict quantitatively under which conditions turbophoresis, including the virtual mass effect, the Saffman lift force, and the Magnus force may contribute significantly to sediment transport in radial direction and compare these results to experimental observations. The contribution of turbophoresis is mostly limited to large particles (>50 μm) in transport mains, and not expected to play a major role in distribution mains. The Saffman lift force may enhance this process to some degree. The Magnus force is not expected to play any significant role in drinking water distribution systems. © 2010 Elsevier Ltd. All rights reserved.

  5. On the size distribution of collision fragments of NLC dust particles and their relevance to meteoric smoke particles

    Science.gov (United States)

    Havnes, O.; Gumbel, J.; Antonsen, T.; Hedin, J.; La Hoz, C.

    2014-10-01

    We present the results from a new dust probe MUDD on the PHOCUS payload which was launched in July 2011. In the interior of MUDD all the incoming NLC/PMSE icy dust particles will collide, at an impact angle ~70° to the surface normal, with a grid constructed such that no dust particles can directly hit the bottom plate of the probe. Only collision fragments will continue down towards the bottom plate. We determine an energy distribution of the charged fragments by applying a variable electric field between the impact grid and the bottom plate of MUDD. We find that ~30% of the charged fragments have kinetic energies less than 10 eV, ~20% have energies between 10 and 20 eV while ~50% have energies above 20 eV. The transformation of limits in kinetic energy for ice or meteoric smoke particles (MSP) to radius is dependent on many assumptions, the most crucial being fragment velocity. We find, however, that the sizes of the charged fragments most probably are in the range of 1 to 2 nm if meteoric smoke particles (MSP), and slightly higher if ice particles. The observed high charging fraction and the dominance of fragment sizes below a few nm makes it very unlikely that the fragments can consist mainly of ice but that they must be predominantly MSP as predicted by Havnes and Næsheim (2007) and recently observed by Hervig et al. (2012). The MUDD results indicate that MSP are embedded in NLC/PMSE ice particles with a minimum volume filling factor of ~.05% in the unlikely case that all embedded MSP are released and charged. A few % volume filling factor (Hervig et al., 2012) can easily be reached if ~10% of the MSP are released and that their charging probability is ~0.1.

  6. Particle size distributions by transmission electron microscopy: an interlaboratory comparison case study

    Science.gov (United States)

    Rice, Stephen B; Chan, Christopher; Brown, Scott C; Eschbach, Peter; Han, Li; Ensor, David S; Stefaniak, Aleksandr B; Bonevich, John; Vladár, András E; Hight Walker, Angela R; Zheng, Jiwen; Starnes, Catherine; Stromberg, Arnold; Ye, Jia; Grulke, Eric A

    2015-01-01

    This paper reports an interlaboratory comparison that evaluated a protocol for measuring and analysing the particle size distribution of discrete, metallic, spheroidal nanoparticles using transmission electron microscopy (TEM). The study was focused on automated image capture and automated particle analysis. NIST RM8012 gold nanoparticles (30 nm nominal diameter) were measured for area-equivalent diameter distributions by eight laboratories. Statistical analysis was used to (1) assess the data quality without using size distribution reference models, (2) determine reference model parameters for different size distribution reference models and non-linear regression fitting methods and (3) assess the measurement uncertainty of a size distribution parameter by using its coefficient of variation. The interlaboratory area-equivalent diameter mean, 27.6 nm ± 2.4 nm (computed based on a normal distribution), was quite similar to the area-equivalent diameter, 27.6 nm, assigned to NIST RM8012. The lognormal reference model was the preferred choice for these particle size distributions as, for all laboratories, its parameters had lower relative standard errors (RSEs) than the other size distribution reference models tested (normal, Weibull and Rosin–Rammler–Bennett). The RSEs for the fitted standard deviations were two orders of magnitude higher than those for the fitted means, suggesting that most of the parameter estimate errors were associated with estimating the breadth of the distributions. The coefficients of variation for the interlaboratory statistics also confirmed the lognormal reference model as the preferred choice. From quasi-linear plots, the typical range for good fits between the model and cumulative number-based distributions was 1.9 fitted standard deviations less than the mean to 2.3 fitted standard deviations above the mean. Automated image capture, automated particle analysis and statistical evaluation of the data and fitting coefficients provide a

  7. Abundance, size distribution and bacterial colonization of transparent exopolymeric particles (TEP) during spring in the Kattegat

    DEFF Research Database (Denmark)

    Mari, X.; Kiørboe, Thomas

    1996-01-01

    The abundance, size distribution and bacterial colonization of transparent exopolymeric particles (TEP) were monitored in the Kattegat (Denmark) at weekly intervals throughout the spring (February-May) encompassing the spring diatom bloom. These recently discovered particles are believed to be fo......The abundance, size distribution and bacterial colonization of transparent exopolymeric particles (TEP) were monitored in the Kattegat (Denmark) at weekly intervals throughout the spring (February-May) encompassing the spring diatom bloom. These recently discovered particles are believed...... of beta differed significantly from three, probably because TEP are fractal. All TEP were colonized by bacteria, and bacteria were both attached to the surface of and embedded in TEP. Yet the number of attached bacteria per TEP was related neither to the surface area nor the volume, but rather scaled...

  8. Effects of Particle Size Distribution on the Burn Ability of Limestone

    Directory of Open Access Journals (Sweden)

    Ismaila E. SULEIMAN

    2013-11-01

    Full Text Available The effect of particle size reduction on the burn ability of Limestone was investigated using the limestone obtained from Obajana Cement Mines. Limestone samples were grinded and were classified into following particles size distribution: 90µm, 200µm, 250µm and 500µm graduated in different sieve sizes. The decomposition rates of these samples were monitored under the same temperature condition in a pre-heated furnace of 1000°C and at constant time interval of 0-35 minutes. From the results of the investigation, the material with particle size distribution of 90µm has the fastest reaction rate of 0.1369g/min and highest lime conversion of 52.0 weight percent; loss on ignition being 48 weight percent. This reaction rate increases as the particle size decreases from 500µm to 90µm.

  9. Particle size distribution models of small angle neutron scattering pattern on ferro fluids

    International Nuclear Information System (INIS)

    Sistin Asri Ani; Darminto; Edy Giri Rachman Putra

    2009-01-01

    The Fe 3 O 4 ferro fluids samples were synthesized by a co-precipitation method. The investigation of ferro fluids microstructure is known to be one of the most important problems because the presence of aggregates and their internal structure influence greatly the properties of ferro fluids. The size and the size dispersion of particle in ferro fluids were determined assuming a log normal distribution of particle radius. The scattering pattern of the measurement by small angle neutron scattering were fitted by the theoretical scattering function of two limitation models are log normal sphere distribution and fractal aggregate. Two types of particle are detected, which are presumably primary particle of 30 Armstrong in radius and secondary fractal aggregate of 200 Armstrong with polydispersity of 0.47 up to 0.53. (author)

  10. Monte Carlo calculations of the depth-dose distribution in skin contaminated by hot particles

    Energy Technology Data Exchange (ETDEWEB)

    Patau, J.-P. (Toulouse-3 Univ., 31 (France))

    1991-01-01

    Accurate computer programs were developed in order to calculate the spatial distribution of absorbed radiation doses in the skin, near high activity particles (''hot particles''). With a view to ascertaining the reliability of the codes the transport of beta particles was simulated in a complex configuration used for dosimetric measurements: spherical {sup 60}Co sources of 10-1000 {mu}m fastened to an aluminium support with a tissue-equivalent adhesive overlaid with 10 {mu}m thick aluminium foil. Behind it an infinite polystyrene medium including an extrapolation chamber was assumed. The exact energy spectrum of beta emission was sampled. Production and transport of secondary knock-on electrons were also simulated. Energy depositions in polystyrene were calculated with a high spatial resolution. Finally, depth-dose distributions were calculated for hot particles placed on the skin. The calculations will be continued for other radionuclides and for a configuration suited to TLD measurements. (author).

  11. Spin-dependent observable effect for free particles using the arrival time distribution

    International Nuclear Information System (INIS)

    Ali, Md. Manirul; Majumdar, A.S.; Home, Dipankar; Sengupta, Shyamal

    2003-01-01

    The mean arrival time of free particles is computed using the quantum-mechanical probability current. This is uniquely determined in the nonrelativistic limit of Dirac equation, although the Schroedinger probability current has an inherent nonuniqueness. Since the Dirac probability current contains a spin-dependent term, an arrival time distribution based on the probability current shows an observable spin-dependent effect, even for free particles. This arises essentially from relativistic quantum dynamics, but persists even in the nonrelativistic regime

  12. A Topology Visualization Early Warning Distribution Algorithm for Large-Scale Network Security Incidents

    Directory of Open Access Journals (Sweden)

    Hui He

    2013-01-01

    Full Text Available It is of great significance to research the early warning system for large-scale network security incidents. It can improve the network system’s emergency response capabilities, alleviate the cyber attacks’ damage, and strengthen the system’s counterattack ability. A comprehensive early warning system is presented in this paper, which combines active measurement and anomaly detection. The key visualization algorithm and technology of the system are mainly discussed. The large-scale network system’s plane visualization is realized based on the divide and conquer thought. First, the topology of the large-scale network is divided into some small-scale networks by the MLkP/CR algorithm. Second, the sub graph plane visualization algorithm is applied to each small-scale network. Finally, the small-scale networks’ topologies are combined into a topology based on the automatic distribution algorithm of force analysis. As the algorithm transforms the large-scale network topology plane visualization problem into a series of small-scale network topology plane visualization and distribution problems, it has higher parallelism and is able to handle the display of ultra-large-scale network topology.

  13. Reconstruction of particle size distributions and anisometry in polydisperse systems by the small-angle scattering method

    International Nuclear Information System (INIS)

    Plavnik, G.M.

    1986-01-01

    A technique to obtain particle size distributions from small-angle scattering data is suggested. It is applicable to systems of particles of arbitrary but identical shape, roughly equiaxial particles of various shapes, and particles of unknown shape. The procedure involved in the determination of the micropore sizes in Pt+Al 2 O 3 catalysts is demonstrated. (author)

  14. Simulation study of effects of initial particle size distribution on dissolution

    International Nuclear Information System (INIS)

    Wang, G.; Xu, D.S.; Ma, N.; Zhou, N.; Payton, E.J.; Yang, R.; Mills, M.J.; Wang, Y.

    2009-01-01

    Dissolution kinetics of γ' particles in binary Ni-Al alloys with different initial particle size distributions (PSD) is studied using a three-dimensional (3D) quantitative phase field model. By linking model inputs directly to thermodynamic and atomic mobility databases, microstructural evolution during dissolution is simulated in real time and length scales. The model is first validated against analytical solution for dissolution of a single γ' particle in 1D and numerical solution in 3D before it is applied to investigate the effects of initial PSD on dissolution kinetics. Four different types of PSD, uniform, normal, log-normal and bimodal, are considered. The simulation results show that the volume fraction of γ' particles decreases exponentially with time, while the temporal evolution of average particle size depends strongly on the initial PSD

  15. Analysis of tecniques for measurement of the size distribution of solid particles

    Directory of Open Access Journals (Sweden)

    F. O. Arouca

    2005-03-01

    Full Text Available Determination of the size distribution of solid particles is fundamental for analysis of the performance several pieces of equipment used for solid-fluid separation. The main objective of this work is to compare the results obtained with two traditional methods for determination of the size grade distribution of powdery solids: the gamma-ray attenuation technique (GRAT and the LADEQ test tube technique. The effect of draining the suspension in the two techniques used was also analyzed. The GRAT can supply the particle size distribution of solids through the monitoring of solid concentration in experiments on batch settling of diluted suspensions. The results show that use of the peristaltic pump in the GRAT and the LADEQ methods produced a significant difference between the values obtained for the parameters of the particle size model.

  16. Vertical distribution of aerosol particles and NO x close to a motorway

    Science.gov (United States)

    Imhof, D.; Weingartner, E.; Vogt, U.; Dreiseidler, A.; Rosenbohm, E.; Scheer, V.; Vogt, R.; Nielsen, O. J.; Kurtenbach, R.; Corsmeier, U.; Kohler, M.; Baltensperger, U.

    In May 2001, the large-scale field project BAB II was performed at the highly frequented motorway BAB (Bundesautobahn) A656 with two traffic lanes in each direction between the German cities Heidelberg and Mannheim. Extensive measurements of air pollutants were carried out on both sides of the motorway. In a distance of 60 m (north side) and 84 m (south side) to the traffic lanes, two 52-m-high towers were installed, at which electrically powered elevators were fixed. In these elevators, two NO x analysers, an Electrical Low Pressure Impactor (ELPI; measurement of the particle number size distribution in the diameter range D between 30 nm and 10 μm) and a Diffusion Charger (DC; measuring the particle surface area concentration), were operated to record continuous vertical profiles from 5 to 50 m above the earth's surface. On the upwind side, particle number and surface area concentration as well as NO x values were constant over the entire height profile. On the downwind side, increased concentrations appeared in the near-ground range: in the forenoon, a monotonous decrease in pollutant concentrations with increasing height was found, while around noon the concentration maximum of the particles was slightly shifted to 10 m above ground. This height dependence was found for two different size ranges, i.e., for particles with D1μm, abrasion and resuspension products). In the size range between 300 and 700 nm, no height dependence was found, corroborating the fact that motor traffic emits only few particles in this size range. On the downwind side of the motorway, only background concentrations were measured above 25 m. The results of the profile measurements were confirmed by stationary measurements of particle size distributions with Scanning Mobility Particle Sizers (SMPS) at various heights. A good correlation between particle surface area and NO x concentration was observed. Vehicle emission factors were determined for the particle surface area, number and

  17. Intermethod comparison of the particle size distributions of colloidal silica nanoparticles.

    Science.gov (United States)

    Tuoriniemi, Jani; Johnsson, Ann-Cathrin J H; Holmberg, Jenny Perez; Gustafsson, Stefan; Gallego-Urrea, Julián A; Olsson, Eva; Pettersson, Jan B C; Hassellöv, Martin

    2014-06-01

    There can be a large variation in the measured diameter of nanoparticles depending on which method is used. In this work, we have strived to accurately determine the mean particle diameter of 30-40 nm colloidal silica particles by using six different techniques. A quantitative agreement between the particle size distributions was obtained by scanning electron microscopy (SEM), and electrospray-scanning mobility particle sizer (ES-SMPS). However, transmission electron microscopy gave a distribution shifted to smaller sizes. After confirming that the magnification calibration was consistent, this was attributed to sample preparation artifacts. The hydrodynamic diameter, d h , was determined by dynamic light scattering (DLS) both in batch mode, and hyphenated with sedimentation field flow fractionation. Surprisingly the d h were smaller than the SEM, and ES-SMPS diameters. A plausible explanation for the smaller sizes found with DLS is that a permeable gel layer forms on the particle surface. Results from nanoparticle tracking analysis were strongly biased towards larger diameters, most likely because the silica particles provide low refractive index contrast. Calculations confirmed that the sensitivity is, depending on the shape of the laser beam, strongly size dependent for particles with diameters close to the visualization limit.

  18. The Inertia Weight Updating Strategies in Particle Swarm Optimisation Based on the Beta Distribution

    Directory of Open Access Journals (Sweden)

    Petr Maca

    2015-01-01

    Full Text Available The presented paper deals with the comparison of selected random updating strategies of inertia weight in particle swarm optimisation. Six versions of particle swarm optimization were analysed on 28 benchmark functions, prepared for the Special Session on Real-Parameter Single Objective Optimisation at CEC2013. The random components of tested inertia weight were generated from Beta distribution with different values of shape parameters. The best analysed PSO version is the multiswarm PSO, which combines two strategies of updating the inertia weight. The first is driven by the temporally varying shape parameters, while the second is based on random control of shape parameters of Beta distribution.

  19. Gas/particle partitioning and particle size distribution of PCDD/Fs and PCBs in urban ambient air.

    Science.gov (United States)

    Barbas, B; de la Torre, A; Sanz, P; Navarro, I; Artíñano, B; Martínez, M A

    2018-05-15

    Urban ambient air samples, including gas-phase (PUF), total suspended particulates (TSP), PM 10 , PM 2.5 and PM 1 airborne particle fractions were collected to evaluate gas-particle partitioning and size particle distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). Clausius-Clapeyron equation, regressions of logKp vs logP L and logK OA, and human respiratory risk assessment were used to evaluate local or long-distance transport sources, gas-particle partitioning sorption mechanisms, and implications for health. Total ambient air levels (gas phase+particulate phase) of TPCBs and TPCDD/Fs, were 437 and 0.07pgm -3 (median), respectively. Levels of PCDD/F in the gas phase (0.004-0.14pgm -3 , range) were significantly (pgas phase, and displayed maximum levels in warm seasons, probably due to an increase in evaporation rates, supported by significant and strong positive dependence on temperature observed for several congeners. No significant differences in PCDD/Fs and PCBs concentrations were detected between the different particle size fractions considered (TSP, PM 10 , PM 2.5 and PM 1 ), reflecting that these chemicals are mainly bounded to PM 1 . The toxic content of samples was also evaluated. Total toxicity (PUF+TSP) attributable to dl-PCBs (13.4fg-TEQ 05 m -3 , median) was higher than those reported for PCDD/Fs (6.26fg-TEQ 05 m -3 ). The inhalation risk assessment concluded that the inhalation of PCDD/Fs and dl-PCBs pose a low cancer risk in the studied area. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Civilian gunshot wounds to the genitourinary tract: incidence, anatomic distribution, associated injuries, and outcomes.

    Science.gov (United States)

    Najibi, Soheil; Tannast, Moritz; Latini, Jerilyn M

    2010-10-01

    Gunshot wounds (GSW) affecting the genitourinary (GU) system in civilians are uncommon. This study describes the incidence, anatomic distribution, demographics, associated injuries, management, and outcomes after civilian GU GSW. A Level 1 Trauma Center Registry was used to retrospectively identify all patients who sustained GU GSW (January 1997-December 2008). Patient information was abstracted from the Registry, medical, and autopsy records. Multivariate regression detected significant factors associated with mortality. Of 2941 civilian GSW patients, 309 (10.5%) sustained GU injury with/without associated injuries. Mean age was 30.4 ± 11.9 years (range 6.6-80.6 years); 289 patients (93.5%) were male. Mean Injury Severity Score (ISS) 22.2 ± 15.4 (1-75). Incidence of GU GSW increased during the study period. GSW affected the kidneys (55%), scrotum (21%), bladder (19%), testicle (12%), penis (8%), some patients having more than 1 GU organ injured. A total of 284 patients (92%) experienced at least 1 other organ injury. Most GU GSW were managed surgically (mean 2.2 ± 2.0; 0-13 surgeries/patient). There was a 27% (n = 84) overall mortality, with 16% (n = 50) dead on arrival. Mortality and ISS were correlated (P = 0.002; hazard ratio = 3.0; 95% confidence interval 3.0-3.0CI). Large vessel, head/neck, kidney, vascular, heart, lung, spine, and spinal cord injury were statistically significant risk factors for death. GU injury occurred in 10.5% of 2941 civilian GSW patients. Associated injuries were very common, with many cases involving multiple organs. Most injuries (90%) were managed surgically. Mortality is usually the result of associated nongenitourinary injuries. A high index of suspicion for injuries affecting other organs is necessary in managing GU GSW trauma patients. Copyright © 2010 Elsevier Inc. All rights reserved.

  1. Self-consistent particle distribution of a bunched beam in RF field

    CERN Document Server

    Batygin, Y K

    2002-01-01

    An analytical solution for the self-consistent particle equilibrium distribution in an RF field with transverse focusing is found. The solution is attained in the approximation of a high brightness beam. The distribution function in phase space is determined as a stationary function of the energy integral. Equipartitioning of the beam distribution between degrees of freedom follows directly from the choice of the stationary distribution function. Analytical expressions for r-z equilibrium beam profile and maximum beam current in RF field are obtained.

  2. Reduction of the ionization loss distribution width of several simultaneous relativistic particles traversing a scintillation counter

    CERN Document Server

    Aderholz, M; Matthewson, R

    1975-01-01

    A Poisson distribution of number of electrons at the input stages of a photomultiplier has been folded into a Landau-Symon distribution of ionization losses in a plastic scintillator and a distribution of the smallest value out of n detectors was derived analytically for m simultaneous particles. A group of four identical scintillation counters was constructed and the smallest of the four output pulses was used for selective triggering of the bubble chamber flash with the greater precision engendered by the considerably reduced distribution width. (22 refs).

  3. Measurements of the charged particle multiplicity distribution in restricted rapidity intervals

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Ariztizabal, F; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Gaitan, V; Garrido, L; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Engelhardt, A; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Knobloch, J; Lehraus, Ivan; Markou, C; Martin, E B; Mato, P; Meinhard, H; Minten, Adolf G; Miquel, R; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wiedenmann, W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Passalacqua, L; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Pepé-Altarelli, M; Dorris, S J; Halley, A W; ten Have, I; Knowles, I G; Lynch, J G; Morton, W T; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Smith, M G; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moneta, L; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kneringer, E; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Settles, Ronald; Seywerd, H C J; Stierlin, U; Saint-Denis, R; Wolf, G; Alemany, R; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Musolino, G; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Abbaneo, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Triggiani, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Mir, M; Perrodo, P; Strong, J A; Bertin, V; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Duarte, H; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Rosowsky, A; Roussarie, A; Schuller, J P; Schwindling, J; Si Mohand, D; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Cartwright, S L; Combley, F; Dawson, I; Köksal, A; Letho, M; Newton, W M; Rankin, C; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1995-01-01

    Charged particle multiplicity distributions have been measured with the ALEPH detector in restricted rapidity intervals |Y| \\leq 0.5,1.0, 1.5,2.0\\/ along the thrust axis and also without restriction on rapidity. The distribution for the full range can be parametrized by a log-normal distribution. For smaller windows one finds a more complicated structure, which is understood to arise from perturbative effects. The negative-binomial distribution fails to describe the data both with and without the restriction on rapidity. The JETSET model is found to describe all aspects of the data while the width predicted by HERWIG is in significant disagreement.

  4. Effect of sulfate and carbonate minerals on particle-size distributions in arid soils

    Science.gov (United States)

    Goossens, Dirk; Buck, Brenda J.; Teng, Yuazxin; Robins, Colin; Goldstein, Harland L.

    2014-01-01

    Arid soils pose unique problems during measurement and interpretation of particle-size distributions (PSDs) because they often contain high concentrations of water-soluble salts. This study investigates the effects of sulfate and carbonate minerals on grain-size analysis by comparing analyses in water, in which the minerals dissolve, and isopropanol (IPA), in which they do not. The presence of gypsum, in particular, substantially affects particle-size analysis once the concentration of gypsum in the sample exceeds the mineral’s solubility threshold. For smaller concentrations particle-size results are unaffected. This is because at concentrations above the solubility threshold fine particles cement together or bind to coarser particles or aggregates already present in the sample, or soluble mineral coatings enlarge grains. Formation of discrete crystallites exacerbates the problem. When soluble minerals are dissolved the original, insoluble grains will become partly or entirely liberated. Thus, removing soluble minerals will result in an increase in measured fine particles. Distortion of particle-size analysis is larger for sulfate minerals than for carbonate minerals because of the much higher solubility in water of the former. When possible, arid soils should be analyzed using a liquid in which the mineral grains do not dissolve, such as IPA, because the results will more accurately reflect the PSD under most arid soil field conditions. This is especially important when interpreting soil and environmental processes affected by particle size.

  5. Municipal distribution and trends in bladder cancer incidence in health area of León, Spain (1996-2010).

    Science.gov (United States)

    del Canto, M; García-Martínez, L; Fernández-Villa, T; Molina, A J; Campanario, F; García-Sanz, M; López-Abente, G; Honrado, E; Martín-Sánchez, V

    2015-01-01

    Spain is a country where bladder cancer incidence and mortality rates are some of the highest in the world. The aim of this study is to know the incidence, trends and geographical distribution of bladder cancer in the health area of León. the new cases of bladder cancer (CIE-188) in patients residing in the health area of León and registered in the Hospital Tumor Registry of the Centro Asistencial Universitario in León (Spain) between 1996-2010 were included in this study. Triennial crude incidence and adjusted incidence rates to the worldwide and European population were calculated. Population data of the municipalities of Leon (Spain) were obtained from National Institute of Statistic of Spain (INE, Instituto Nacional de Estadística). Data were disaggregated by sex-groups and five-year age groups. Spatial distribution of smoothed municipal relative risks (RR) of bladder cancer was carried out using a Besag, York and Mollié model. Bayesian model were used to calculate the posterior probability (PP) of RR greater than one. 1.573 cases were included. Incidence rates standardized to European population increased among men from 20,8/100.000 (1996-98) to 33,1/100.000 (2006-2008) and among women these rates increased from 1,9/100.000 to 5,9/100.000 for the same period of time. No relevant differences were found in the municipal distribution of the incidences. bladder cancer incidence rates are high in the European context. Rising trends in incidence in both sexs, particularly in women are observed. Copyright © 2014 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  6. Scaled momentum distributions of charged particles in dijet photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2009-04-15

    The scaled momentum distributions of charged particles in jets have been measured for dijet photoproduction with the ZEUS detector at HERA using an integrated luminosity of 359 pb{sup -1}. The distributions are compared to predictions based on perturbative QCD carried out in the framework of the modified leading-logarithmic approximation (MLLA) and assuming local parton-hadron duality (LPHD). The universal MLLA scale, {lambda}{sub eff}, and the LPHD parameter, {kappa}{sup ch}, are extracted. (orig.)

  7. Scaled momentum distributions of charged particles in dijet photoproduction at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-04-01

    The scaled momentum distributions of charged particles in jets have been measured for dijet photoproduction with the ZEUS detector at HERA using an integrated luminosity of 359 pb -1 . The distributions are compared to predictions based on perturbative QCD carried out in the framework of the modified leading-logarithmic approximation (MLLA) and assuming local parton-hadron duality (LPHD). The universal MLLA scale, Λ eff , and the LPHD parameter, κ ch , are extracted. (orig.)

  8. Statistical distribution for generalized ideal gas of fractional-statistics particles

    International Nuclear Information System (INIS)

    Wu, Y.

    1994-01-01

    We derive the occupation-number distribution in a generalized ideal gas of particles obeying fractional statistics, including mutual statistics, by adopting a state-counting definition. When there is no mutual statistics, the statistical distribution interpolates between bosons and fermions, and respects a fractional exclusion principle (except for bosons). Anyons in a strong magnetic field at low temperatures constitute such a physical system. Applications to the thermodynamic properties of quasiparticle excitations in the Laughlin quantum Hall fluid are discussed

  9. Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation.

    Science.gov (United States)

    Shiraiwa, Manabu; Yee, Lindsay D; Schilling, Katherine A; Loza, Christine L; Craven, Jill S; Zuend, Andreas; Ziemann, Paul J; Seinfeld, John H

    2013-07-16

    Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process.

  10. Determination of particle size distribution of salt crystals in aqueous slurries

    International Nuclear Information System (INIS)

    Miller, A.G.

    1977-10-01

    A method for determining particle size distribution of water-soluble crystals in aqueous slurries is described. The salt slurries, containing sodium salts of predominantly nitrate, but also nitrite, sulfate, phosphate, aluminates, carbonate, and hydroxide, occur in radioactive, concentrated chemical waste from the reprocessing of nuclear fuel elements. The method involves separating the crystals from the aqueous phase, drying them, and then dispersing the crystals in a nonaqueous medium based on nitroethane. Ultrasonic treatment is important in dispersing the sample into its fundamental crystals. The dispersed crystals are sieved into appropriate size ranges for counting with a HIAC brand particle counter. A preponderance of very fine particles in a slurry was found to increase the difficulty of effecting complete dispersion of the crystals because of the tendency to retain traces of aqueous mother liquor. Traces of moisture produce agglomerates of crystals, the extent of agglomeration being dependent on the amount of moisture present. The procedure is applicable to particles within the 2 to 600 μm size range of the HIAC particle counter. The procedure provides an effective means for measuring particle size distribution of crystals in aqueous salt slurries even when most crystals are less than 10 μm in size. 19 figures

  11. Particle and solution phase depth distributions of transuranics and 55Fe in the North Pacific

    International Nuclear Information System (INIS)

    Livingston, H.D.; Mann, D.R.; Casso, S.A.; Schneider, D.L.; Surprenant, L.D.; Bowen, V.T.

    1987-01-01

    In situ large volume filtration and chemisorption techniques were used to collect samples from the North Pacific for radiochemical analyses of fallout transuranics and 55 Fe in filterable and filtered phases. The data cover several locations for surface collections and a detailed depth profile north of Hawaii at 30 0 N. The observed partition of these nuclides between suspended particulate and filtered phases is directly linked to the rates at which they are moved downward through the water column in association with sinking particles. Particulate phases in open ocean surface waters contain higher Pu than subsurface particulates. 241 Am was found to exhibit much stronger particle association in accord with its known greater particle reactivity. In the high Pu deep water layer, particle associated Pu dropped to close to 1% of total Pu concentration. Together with a correlated increase in the proportion of oxidized Pu in this layer close to the sediment-water interface, this is clear evidence of remobilization of Pu from particles at, or near to, the interface. 55 Fe distributions on filtered particulates indicate a much deeper depth distribution relative to the transuranics. This may reflect both a higher particle association reactivity in respect to scavenging and a longer exposure history to scavenging. (author)

  12. Determination of the particle size distribution in a powder using radiotracers

    International Nuclear Information System (INIS)

    Revilla D, R.

    1974-01-01

    To determine experimentally the particle size distribution in a powder the meshed method is generally used. This method has the disadvantage that in the obtained distribution is not observed at detail the fine structure of such distribution. In this work, a method for obtaining the distribution of particle size using radiotracers is presented. In the obtained distribution by this method it is observed with more detail the fine structure of the distribution, comparing with the obtained results by the classical method of meshed. The radiotracer method has major resolution for the experimental determination mentioned. In the chapter 1, it is done a brief analysis about theoretical aspects related with the method. In the first part it is analysed the particle behavior (sedimenting) in a fluid. The second part treats the relating with the radioactivity of an activated material as well as its detection. In the chapter 2, a description of the method is done also the experimental problems to applying to the alumina crystals sample are discussed. In the chapter 3 the obtained results and the mistake calculations in such results are showed. Finally, in the chapter 4 the conclusions and recommendations are given which is possible to obtain better results and improve to those in this work were obtained. (Author)

  13. Development of the theory of momentum distribution of particles with regard to quantum phenomena

    Science.gov (United States)

    Starostin, A. N.; Gryaznov, V. K.; Petrushevich, Yu. V.

    2017-11-01

    A generalization of the theory of quantum asymptotics for the particle distribution function for large values of momentum is given that takes into account the energy exchange between a particle and an impurity. It is shown that, compared with the known power-law asymptotics, an additional exponential dependence on the kinetic energy arises with effective temperature higher than the temperature of the medium by a factor of the ratio of the impurity mass to the particle mass for a quantum correction to the Maxwell distribution function. New formulas are obtained for the rates of thermonuclear and threshold chemical reactions, that allow one to get rid of the inconsistencies of the previous theory when comparing with experiment.

  14. Particle size distribution and property of bacteria attached to carbon fines in drinking water treatment

    Directory of Open Access Journals (Sweden)

    Wang Leilei

    2008-06-01

    Full Text Available The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon (GAC filter in a drinking water treatment plant were investigated. The average total concentration of particles in the sand filter effluent during a filter cycle was 148 particles/mL, 27 of which were larger than 2 µm in size. The concentration in the GAC effluent (561 particles/mL was significantly greater than that in the sand filter effluent. The concentration of particles larger than 2 µm in the GAC filter effluent reached 201 particles/mL, with the amount of particles with sizes between 2 µm and 15 µm increasing. The most probable number (MPN of carbon fines reached 43 unit/L after six hours and fines between 0.45 µm and 8.0 µm accounted for more than 50%. The total concentration of outflowing bacteria in the GAC filter effluent, 350 CFU (colony-forming units/mL, was greater than that in the sand filter effluent, 210 CFU/mL. The desorbed bacteria concentration reached an average of 310 CFU/mg fines. The disinfection efficiency of desorbed bacteria was lower than 40% with 1.5 mg/L of chlorine. The disinfection effect showed that the inactivation rate with 2.0 mg/L of chloramine (90% was higher than that with chlorine (70%. Experimental results indicated that the high particle concentration in raw water and sedimentation effluent led to high levels of outflowing particles in the sand filter effluent. The activated carbon fines in the effluent accounted for a small proportion of the total particle amount, but the existing bacteria attached to carbon fines may influence the drinking water safety. The disinfection efficiency of desorbed bacteria was lower than that of free bacteria with chlorine, and the disinfection effect on bacteria attached to carbon fines with chloramine was better than that with only chlorine.

  15. The distribution and aggregatability of intramembrane particles in phenylhydrazine-treated human erythrocytes

    NARCIS (Netherlands)

    Lelkes, G. (Gábor); Fodor, I.; Lelkes, G. (György); Hollán, S.R.; Verkleij, A.J.

    1988-01-01

    Freeze-fracture analysis of phenylhydrazine-treated, unfixed human erythrocytes showed a random distribution of intramembrane particles both over membrane-bound Heinz-bodies and in the intervening areas when examined after fast freezing in liquid propane. The same results was obtained when unfixed,

  16. Distribution functions for systems of charged particles in spatially inhomogeneous medium

    Energy Technology Data Exchange (ETDEWEB)

    Petrina, D.Ya. (AN Ukrainskoj SSR, Kiev. Inst. Teoreticheskoj Fiziki)

    1984-04-01

    Equations for distribution functions of systems of charged particles in a medium with heterogeneities are investigated. In the self-consistent field approximation they are reduced to nonlinear Poisson-Boltzmann equations with boundary conditions on surfaces of the heterogeneities. An analogue of the subtraction procedure in quantun field theory is used in the proof of the existence of the solution.

  17. Alpha particle angular distribution of oriented 189,191,193Bi

    International Nuclear Information System (INIS)

    Berkes, I.; Bouvier, R.; De Jesus, M.; Hadjout, J.P.; Massaq, M.

    1998-01-01

    Angular distribution data for α particles emitted in the enhanced decay of on-line oriented neutron deficient isotopes 189,191,193 Bi near mid-shell (N=104) are presented. They give additional support for the recent finding that anisotropic α emission in enhanced decays from near-spherical nuclei is mainly determined by nuclear structure effects. (authors)

  18. Particle size-dependent organ distribution of gold nanoparticles after intravenous administration

    NARCIS (Netherlands)

    De Jong, Wim H.; Hagens, Werner I.; Krystek, Petra; Burger, Marina C.; Sips, Adriënne J A M; Geertsma, Robert E.

    2008-01-01

    A kinetic study was performed to determine the influence of particle size on the in vivo tissue distribution of spherical-shaped gold nanoparticles in the rat. Gold nanoparticles were chosen as model substances as they are used in several medical applications. In addition, the detection of the

  19. Work distribution for a particle moving in an optical trap and non ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. We propose a simple approach to derive an exact analytical expression of work distribution for a system consisting of a colloidal particle trapped in an optical harmonic potential well, which is being pulled at a constant velocity through a solution represented by a non-Markovian bath. The thermal environment is ...

  20. Charged particle density distributions in Au·Au collisions at ...

    Indian Academy of Sciences (India)

    Charged particle pseudorapidity distributions have been measured in Au·Au collisions using the BRAHMS ... Relativistic heavy-ion collisions; charged hadron production; pseudorapidity distribu- tions; centrality .... the predictions of two different theoretical models: (i) the high density gluon saturation model of Kharzeev and ...

  1. Momentum distribution of charged particles in jets in dijet events and ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 87; Issue 2. Momentum distribution of charged particles in jets in dijet events and comparison to perturbative QCD predictions. M E ZOMORRODIAN M HASHEMINIA S M ZABIHINPOUR A MIRJALILI. Research Article Volume 87 Issue 2 August 2016 Article ID 28 ...

  2. Time distribution of shower particle arrivals at various distances from the axis of extensive air shower

    International Nuclear Information System (INIS)

    Vedeneev, O.V.; Kulikov, G.V.; Matsenov, S.I.

    1986-01-01

    Experimental data on time structure of an extensive air shower (EAS) disk obtained at the Mosscow University EAS are presented. Particle distributions in the depth of a shower disk and radii of shower front curvature at distance interval from the axis of the shower 200-600 m, are obtained

  3. Daily micro particle distribution of an experimental recirculating aquaculture system – A case study

    DEFF Research Database (Denmark)

    Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

    2014-01-01

    The particle size distribution (PSD) in a recirculating aquaculture system (RAS) was investigated duringa 24-h cycle. PSD was analyzed in water sampled at several locations in a recirculation loop containing a60-m drum filter, a submerged fixed-bed biofilter and a trickling filter.In relation...

  4. Distribution of concentration of coarse particle-water mixture in horizontal smooth pipe

    Czech Academy of Sciences Publication Activity Database

    Vlasák, Pavel; Chára, Zdeněk; Konfršt, Jiří; Krupička, Jan

    2016-01-01

    Roč. 94, č. 6 (2016), s. 1040-1047 ISSN 0008-4034 R&D Projects: GA ČR GAP105/10/1574 Institutional support: RVO:67985874 Keywords : coarse particle-water mixture * gamma-ray radiometry * concentration distribution * horizontal conveying Subject RIV: BK - Fluid Dynamics Impact factor: 1.356, year: 2016

  5. Work distribution for a particle moving in an optical trap and non ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 121; Issue 5 ... We propose a simple approach to derive an exact analytical expression of work distribution for a system consisting of a colloidal particle trapped in an optical harmonic ... Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085 ...

  6. Effect of ECAP and extrusion on particle distribution in Al-nano ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. In this study equal channel angular pressing (ECAP) and conventional extrusion were used as two different techniques for consolidation of attritioned aluminium powder (45 μm) with varying concentrations of nanoalumina powders (35 nm). The evolution of the homogeneity of the particle distribution in the material.

  7. Computer simulation of structures and distributions of particles in MAGIC fluid

    International Nuclear Information System (INIS)

    Zhu Yongsheng; Umehara, Noritsugu; Ido, Yasushi; Sato, Atsushi

    2006-01-01

    MAGIC (MAG-netic Intelligent Compound) is a solidified magnetic ferrofluid (MF) containing both magnetic particles (MPs) and abrasive particles (APs, nonmagnetic) of micron size. The distribution of APs in MAGIC can be controlled by applying a magnetic field during cooling process of MAGIC fluid. In this paper, the influences of magnetic field, size and concentration of particles on the final structures of MPs and the distributions of APs in MAGIC fluid are preliminarily investigated using Stokesian dynamic (SD) simulation method. Simulation results show that MPs prefer to form strip-like structures in MAGIC fluid, the reason for this phenomenon is mainly attributed to the strong dipolar interactions between them. It is also found that MPs prefer to form big agglomerations in weak magnetic field while chains and strip-like structures in strong magnetic field; no long chains or strip-like structures of MPs are observed in low-concentration MAGIC fluid; and for big-size MPs, pure wall-like structures are formed. Evaluation on the distribution of APs with uniformity coefficient shows that strong magnetic field, high concentration and small-size particles can induce more uniform distribution of APs in MAGIC fluid, the uniformity of APs in MAGIC is about 10% higher than that in normal grinding tools

  8. A simple algorithm for measuring particle size distributions on an uneven background from TEM images

    DEFF Research Database (Denmark)

    Gontard, Lionel Cervera; Ozkaya, Dogan; Dunin-Borkowski, Rafal E.

    2011-01-01

    Nanoparticles have a wide range of applications in science and technology. Their sizes are often measured using transmission electron microscopy (TEM) or X-ray diffraction. Here, we describe a simple computer algorithm for measuring particle size distributions from TEM images in the presence...... application to images of heterogeneous catalysts is presented....

  9. Charged particle density distributions in Au·Au collisions at ...

    Indian Academy of Sciences (India)

    FOUAD RAMI, for the BRAHMS Collaboration. Institut de Recherches Subatomiques, IN2P3-CNRS, Université Louis Pasteur, Strasbourg, France. Abstract. Charged particle pseudorapidity distributions have been measured in Au·Au collisions using the BRAHMS detector at RHIC. The results are presented as a function of ...

  10. Momentum distribution of charged particles in jets in dijet events and ...

    Indian Academy of Sciences (India)

    Inclusive momentum distributions of charged particles are measured in dijet events. Events were produced at the AMY detector with a centre of mass energy of 60 G e V . Our results were compared, on the one hand to those obtained from other e + e − , e p as well as CDF data, and on the other hand to the perturbative QCD ...

  11. Momentum distribution of charged particles in jets in dijet events and ...

    Indian Academy of Sciences (India)

    2016-07-19

    Jul 19, 2016 ... Abstract. Inclusive momentum distributions of charged particles are measured in dijet events. Events were produced at the AMY detector with a centre of mass energy of 60 GeV. Our results were compared, on the one hand to those obtained from other e+ e−. , ep as well as CDF data, and on the other hand ...

  12. Ionic charge state distribution of helium, carbon, oxygen, and iron in an energetic storm particle enhancement

    Science.gov (United States)

    Hovestadt, D.; Klecker, B.; Hoefner, H.; Scholer, M.; Gloeckler, G.; Ipavich, F. M.

    1982-01-01

    An analysis is presented of the ionic charge state distribution of He, C, O and Fe in the energetic storm particle event of September 28-29, 1978. Data were obtained with the ULEZEQ electrostatic analyzer-proportional counter on board the ISEE 3 spacecraft. The He(+)/He(++) ratio between 0.4 and 1 MeV/n is shown to be significantly lower during the energetic storm particle event than during the preceding period of solar flare particle enhancement, with a temporal evolution similar to that of the Fe/He ratio as reported by Klecker et al. (1981). Increases in the mean charge state for oxygen by about 3% and for iron by about 16% are also noted. The temporal variations in charge states are accounted for in terms of first-order Fermi acceleration of the pre-existing solar flare particles by a propagating interplanetary shock wave.

  13. Modelling of Limestone Dissolution in Wet FGD Systems: The Importance of an Accurate Particle Size Distribution

    DEFF Research Database (Denmark)

    Kiil, Søren; Johnsson, Jan Erik; Dam-Johansen, Kim

    1999-01-01

    Danish limestone types with very different particle size distributions (PSDs). All limestones were of a high purity. Model predictions were found to be qualitatively in good agreement with experimental data without any use of adjustable parameters. Deviations between measurements and simulations were...... attributed primarily to the PSD measurements of the limestone particles, which were used as model inputs. The PSDs, measured using a laser diffrac-tion-based Malvern analyser, were probably not representative of the limestone samples because agglomeration phenomena took place when the particles were......In wet flue gas desulphurisation (FGD) plants, the most common sorbent is limestone. Over the past 25 years, many attempts to model the transient dissolution of limestone particles in aqueous solutions have been performed, due to the importance for the development of reliable FGD simu-lation tools...

  14. Childhood and Adolescent Cancer in the State of Pernambuco, Brazil: Incidence, Geographical Distribution, and Association With Environmental Health Indicators.

    Science.gov (United States)

    Bastos, Lídia N V; Silveira, José C; Luna, Carlos F; Lucena-Silva, Norma

    2018-01-01

    Cases of childhood and adolescent cancer diagnosed from 2009 to 2012 in the state of Pernambuco, Brazil, were analyzed considering the patients' sex and age, the type of cancer and the municipality of living to determine the incidence, geographical distribution, and association with environmental health indicators. The spatial distribution pattern of the cancer incidence was estimated using the Global Moran's index. The association between environmental health indicators and cancer incidence was evaluated by multiple regression. From 2009 to 2012, 1261 new cases of cancer were diagnosed in patients younger than 20 years old in the state of Pernambuco. Leukemia/lymphoma were the most common type of cancer contemplating 45.28% of the cases. The average age-adjusted incidence rate was 113 cases per million with no spatial distribution pattern. The municipalities were clustered according to their degree of inequality (P=0.017), human development index (P=0.001), population growth rate (P=0.008), urbanization level (P=0.001), number of agricultural crops per capita (P=0.001), and number of industries per capita (P=0.030). However, only urbanization level was positive correlated with incidence of pediatric cancer (P=0.009) likely because in more developed cities, people are more exposed to potential oncogenic factors, such as air and water pollution and processed and ultraprocessed food. The better access to specialized health services, which increases the chances of early diagnosis, may also contributes for a higher number of cases in more developed cities.

  15. Vertical distribution of radioactive particles in Ottawa River sediment near the Chalk River Laboratories

    International Nuclear Information System (INIS)

    Lee, D.R.; Hartwig, D.S.

    2011-01-01

    Previously, we described an area of above-background levels of radioactivity in the bed of the Ottawa River near the Chalk River Laboratories. The area was about 200 m wide by 400 m long and in water 8 to 30 m deep. The source of the radioactivity was associated with the location of cooling-water discharge. Particles of radioactive material were later recovered from the upper 10-15 cm of sediment and were determined to be sand-sized grains of nuclear fuel and corrosion products. This report provides an examination of the vertical distribution of radioactive particles in the riverbed. Twenty-three dredge samples (representing 1.2 m 2 of riverbed) were collected near the Process Outfall. Each dredge sample was dissected in horizontal intervals 1-cm-thick. Each interval provided a 524 cm 3 sample of sediment that was carefully examined for particulate radioactivity. Approximately 80% of the radioactivity appeared to be associated with discrete particles. Although the natural sediment in the general area is cohesive, silty clay and contains less than 10% sand, the sediment near the Outfall was found to be rich in natural sand, presumably from sources such as winter sanding of roads at the laboratories. The radioactive particles were almost entirely contained in the top-most 10 cm of the river bed. The majority of the particles were found several centimetres beneath the sediment surface and the numbers of particles and the radioactivity of the particles peaked 3 to 7 cm below the sediment surface. Based on the sediment profile, there appeared to have been a marked decrease in the deposition of particulate radioactivity in recent decades. The vertical distribution of radioactive particles indicated that sedimentation is resulting in burial and that the deposition of most of the particulate radioactivity coincided with the operation of Chalk River's NRX reactor from 1947 to 1992. (author)

  16. Effects of soil surface roughness on interrill erosion processes and sediment particle size distribution

    Science.gov (United States)

    Ding, Wenfeng; Huang, Chihua

    2017-10-01

    Soil surface roughness significantly impacts runoff and erosion under rainfall. Few previous studies on runoff generation focused on the effects of soil surface roughness on the sediment particle size distribution (PSD), which greatly affects interrill erosion and sedimentation processes. To address this issue, a rainfall-simulation experiment was conducted with treatments that included two different initial soil surface roughnesses and two rainfall intensities. Soil surface roughness was determined by using photogrammetric method. For each simulated event, runoff and sediment samples were collected at different experimental times. The effective (undispersed) PSD of each sediment sample and the ultimate (after dispersion) PSD were used to investigate the detachment and transport mechanisms involved in sediment movement. The results show that soil surface roughness significantly delayed runoff initiation, but had no significant effect on the steady runoff rate. However, a significant difference in the soil loss rate was observed between the smooth and rough soil surfaces. Sediments from smooth soil surfaces were more depleted in clay-size particles, but more enriched in sand-size particles than those from rough soil surfaces, suggesting that erosion was less selective on smooth than on rough soil surfaces. The ratio of different sizes of transported sediment to the soil matrix indicates that most of the clay was eroded in the form of aggregates, silt-size particles were transported mainly as primary particles, and sand-size particles were predominantly aggregates of finer particles. Soil surface roughness has a crucial effect on the sediment size distribution and erosion processes. Significant differences of the enrichment ratios for the effective PSD and the ultimate PSD were observed under the two soil surface roughness treatments. These findings demonstrate that we should consider each particle size separately rather than use only the total sediment discharge in

  17. Estimates of the Size Distribution of Meteoric Smoke Particles From Rocket-Borne Impact Probes

    Science.gov (United States)

    Antonsen, Tarjei; Havnes, Ove; Mann, Ingrid

    2017-11-01

    Ice particles populating noctilucent clouds and being responsible for polar mesospheric summer echoes exist around the mesopause in the altitude range from 80 to 90 km during polar summer. The particles are observed when temperatures around the mesopause reach a minimum, and it is presumed that they consist of water ice with inclusions of smaller mesospheric smoke particles (MSPs). This work provides estimates of the mean size distribution of MSPs through analysis of collision fragments of the ice particles populating the mesospheric dust layers. We have analyzed data from two triplets of mechanically identical rocket probes, MUltiple Dust Detector (MUDD), which are Faraday bucket detectors with impact grids that partly fragments incoming ice particles. The MUDD probes were launched from Andøya Space Center (69°17'N, 16°1'E) on two payloads during the MAXIDUSTY campaign on 30 June and 8 July 2016, respectively. Our analysis shows that it is unlikely that ice particles produce significant current to the detector, and that MSPs dominate the recorded current. The size distributions obtained from these currents, which reflect the MSP sizes, are described by inverse power laws with exponents of k˜ [3.3 ± 0.7, 3.7 ± 0.5] and k˜ [3.6 ± 0.8, 4.4 ± 0.3] for the respective flights. We derived two k values for each flight depending on whether the charging probability is proportional to area or volume of fragments. We also confirm that MSPs are probably abundant inside mesospheric ice particles larger than a few nanometers, and the volume filling factor can be a few percent for reasonable assumptions of particle properties.

  18. [Distribution of UHMWPE wear particles in periprosthetic tissues of total hip replacements].

    Science.gov (United States)

    Pokorný, D; Slouf, M; Veselý, F; Fulín, P; Jahoda, D; Sosna, A

    2010-04-01

    Information on the distribution of UHMWPE wear particles around joint replacements is essential for the understanding of aseptic loosening of implants. Samples of soft tissue from around total hip arthroplasty (THA), which had a typical appearance of polyethylene granuloma, were collected from the places corresponding to the radiological zones of Gruen and DeLee. The samples were taken from 45 patients (group N1). Since the samples varied in macroscopic appearance and/or the technique of processing, a sub-group of 15 more uniform samples (group N2) were collected by the first author in order to ensure the maxi- mum reliability. The samples were examined for the extent of tissue damage and the amount of particles in each zone. The comprehensive orthopaedic evaluation of tissue damage was carried out as follows: the first author studied the joint replacement revision protocol and pre-operative radiograph in each patient. He evaluated the degree of damage in each zone and wrote down the results in the form of an ordered series according to increasing damage (relational statement). This ordered series was called orthopaedist's statement (OS). The amount of particles in each zone around THA was assessed by the IRc method developed in the laboratory of the second author. IRc method yielded numbers that were proportional to the volume of biologically active particles with size 0.1-10 microm in given zones. The set of numbers from IRc method for each individual case of THA was ordered in a series (relational statement). This ordered series was called a measurement statement (MS) and could be directly compared with orthopaedist's statement (OS). The OS's and MS's for each patient were statistically evaluated, independently for each group (N1=45, N2=15), and two hypotheses were tested: a) distribution of particles in various zones around THA is uniform, b) there is an agreement between OS and MS. The number of UHMWPE wear particles in different periprosthetic zones within

  19. Particle size distribution of the radon progeny and ambient aerosols in the Underground Tourist Route "Liczyrzepa" Mine in Kowary Adit

    Science.gov (United States)

    Wołoszczuk, Katarzyna; Skubacz, Krystian

    2018-01-01

    Central Laboratory for Radiological Protection, in cooperation with Central Mining Institute performed measurements of radon concentration in air, potential alpha energy concentration (PAEC), particle size distribution of the radon progeny and ambient aerosols in the Underground Tourist-Educational Route "Liczyrzepa" Mine in Kowary Adit. A research study was developed to investigate the appropriate dose conversion factors for short-lived radon progeny. The particle size distribution of radon progeny was determined using Radon Progeny Particle Size Spectrometer (RPPSS). The device allows to receive the distribution of PAEC in the particle size range from 0.6 nm to 2494 nm, based on their activity measured on 8 stages composed of impaction plates or diffusion screens. The measurements of the ambient airborne particle size distribution were performed in the range from a few nanometres to about 20 micrometres using Aerodynamic Particle Sizer (APS) spectrometer and the Scanning Mobility Particle Sizer Spectrometer (SMPS).

  20. Determination of the particle size distribution of an aerosol using a diffusion battery

    International Nuclear Information System (INIS)

    Maigne, Jean-Pierre

    1974-02-01

    The principal methods for the treatment of concentration measurements both upstream and downstream of a diffusion battery are reviewed and discussed, the purpose of the measurements being the determination of the aerosol particle size distribution. It is then demonstrated that the resolution of the equations arising from the problem leads to the imposing of physical constraints on the distribution sought, these constraints being more and more restrictive with increasing experimental inaccuracies. An algorithm is proposed which provides an approximate solution to the system of equations, certain predetermined criteria, and the constraints imposed on the distribution being taken into account. (author)

  1. The distribution and incidence of white pine blister rust in central and southeastern Wyoming and northern Colorado

    Science.gov (United States)

    Holly S. J. Kearns; William R. Jacobi

    2007-01-01

    A survey of limber pine (Pinus flexilis James) to determine the geographic distribution, incidence, and severity of white pine blister rust (WPBR) throughout 13 study areas in central and southeastern Wyoming and northern Colorado was conducted from 2002 to 2004. The majority (81.1%) of the 18719 surveyed limber pines>1.37 m tall were classified...

  2. Change in anatomic distribution and incidence of colorectal carcinoma over a period of 15 years - Clinical considerations

    NARCIS (Netherlands)

    Mensink, PBF; Kolkman, JJ; van Baarlen, J; Kleibeuker, JH

    2002-01-01

    PURPOSE: Colorectal cancer is the second most common cancer in the Netherlands. Its incidence rates are among the highest in Europe. In the past decades, a right-sided shift of the subsite location of colorectal cancer has been reported. These changes in anatomic distribution might have clinical

  3. Coevolutionary particle swarm optimization using Gaussian distribution for solving constrained optimization problems.

    Science.gov (United States)

    Krohling, Renato A; Coelho, Leandro dos Santos

    2006-12-01

    In this correspondence, an approach based on coevolutionary particle swarm optimization to solve constrained optimization problems formulated as min-max problems is presented. In standard or canonical particle swarm optimization (PSO), a uniform probability distribution is used to generate random numbers for the accelerating coefficients of the local and global terms. We propose a Gaussian probability distribution to generate the accelerating coefficients of PSO. Two populations of PSO using Gaussian distribution are used on the optimization algorithm that is tested on a suite of well-known benchmark constrained optimization problems. Results have been compared with the canonical PSO (constriction factor) and with a coevolutionary genetic algorithm. Simulation results show the suitability of the proposed algorithm in terms of effectiveness and robustness.

  4. Sampling surface particle size distributions and stability analysis of deep channel in the Pearl River Estuary

    Science.gov (United States)

    Feng, Hao-chuan; Zhang, Wei; Zhu, Yu-liang; Lei, Zhi-yi; Ji, Xiao-mei

    2017-06-01

    Particle size distributions (PSDs) of bottom sediments in a coastal zone are generally multimodal due to the complexity of the dynamic environment. In this paper, bottom sediments along the deep channel of the Pearl River Estuary (PRE) are used to understand the multimodal PSDs' characteristics and the corresponding depositional environment. The results of curve-fitting analysis indicate that the near-bottom sediments in the deep channel generally have a bimodal distribution with a fine component and a relatively coarse component. The particle size distribution of bimodal sediment samples can be expressed as the sum of two lognormal functions and the parameters for each component can be determined. At each station of the PRE, the fine component makes up less volume of the sediments and is relatively poorly sorted. The relatively coarse component, which is the major component of the sediments, is even more poorly sorted. The interrelations between the dynamics and particle size of the bottom sediment in the deep channel of the PRE have also been investigated by the field measurement and simulated data. The critical shear velocity and the shear velocity are calculated to study the stability of the deep channel. The results indicate that the critical shear velocity has a similar distribution over large part of the deep channel due to the similar particle size distribution of sediments. Based on a comparison between the critical shear velocities derived from sedimentary parameters and the shear velocities obtained by tidal currents, it is likely that the depositional area is mainly distributed in the northern part of the channel, while the southern part of the deep channel has to face higher erosion risk.

  5. Hygroscopic growth of tropospheric particle number size distributions over the North China Plain

    Science.gov (United States)

    Achtert, P.; Birmili, W.; Nowak, A.; Wehner, B.; Wiedensohler, A.; Takegawa, N.; Kondo, Y.; Miyazaki, Y.; Hu, M.; Zhu, T.

    2009-01-01

    The hygroscopic growth of atmospheric submicrometer particle size distributions (diameter Dp ranging from 22 to 900 nm) was studied at a rural/suburban site in the North China Plain within the framework of the international Campaigns of Air Quality Research in Beijing and Surrounding Region 2006 (CAREBeijing-2006) research project. The goal was to characterize the regional aerosol in the polluted northeastern plain in China. Size descriptive hygroscopic growth factors (DHGFs) were determined as a function of relative humidity (RH) by relating the particle number size distribution at a dry condition ( 100 nm), the DHGF are substantially higher than in the Aitken particle mode (Dp liquid phase processes in convective clouds. Furthermore, all results concerning the DHGF show a significant dependency on meteorological air masses. The hygroscopic growth of accumulation mode particles correlates significantly with the PM1-mass fraction of sulfate ions determined by chemical analysis. Finally, this investigation provides a parameterization of the hygroscopic growth of 250-nm particles, which might be useful when predicting visibility and radiative forcing and performing atmospheric aerosol model validations.

  6. Shock Reactivity Study on Standard and Reduced Sensitivity Rdx of Different Particle Size Distributions

    Science.gov (United States)

    McGregor, N. M.; Lindfors, A. J.

    2007-12-01

    Embedded gauge experiments have been performed using a three inch high velocity powder gun to assess the effects of RDX particle size and crystal quality on shock induced reactivity in support of the Combat Safe Insensitive Munitions (CSIM) program. Four monomodal experimental compositions containing 73% solids loading by weight and 27% HTPB binder were tested. The compositions were made using either standard or reduced sensitivity grades of RDX in Class 5 or Class 1 150-300 micron sieve cut particle size classes. Results have shown marked changes in the mode of reaction between the two particle size classes. Both RDX grades at the Class 1 sieve cut particle size distribution showed significant reaction at the shock front as well as behind the front. The Class 5 RDX compositions however showed little reaction at the shock front with rapid growth behind the front. Reaction modes were similar but occurring at greater input pressures for the reduced sensitivity grade of RDX compared to the corresponding particle size distribution standard grade RDX counterpart.

  7. Effect of Particle Size Distribution on Wall Heat Flux in Pulverized-Coal Furnaces and Boilers

    Science.gov (United States)

    Lu, Jun

    A mathematical model of combustion and heat transfer within a cylindrical enclosure firing pulverized coal has been developed and tested against two sets of measured data (one is 1993 WSU/DECO Pilot test data, the other one is the International Flame Research Foundation 1964 Test (Beer, 1964)) and one independent code FURN3D from the Argonne National Laboratory (Ahluwalia and IM, 1992). The model called PILC assumes that the system is a sequence of many well-stirred reactors. A char burnout model combining diffusion to the particle surface, pore diffusion, and surface reaction is employed for predicting the char reaction, heat release, and evolution of char. The ash formation model included relates the ash particle size distribution to the particle size distribution of pulverized coal. The optical constants of char and ash particles are calculated from dispersion relations derived from reflectivity, transmissivity and extinction measurements. The Mie theory is applied to determine the extinction and scattering coefficients. The radiation heat transfer is modeled using the virtual zone method, which leads to a set of simultaneous nonlinear algebraic equations for the temperature field within the furnace and on its walls. This enables the heat fluxes to be evaluated. In comparisons with the experimental data and one independent code, the model is successful in predicting gas temperature, wall temperature, and wall radiative flux. When the coal with greater fineness is burnt, the particle size of pulverized coal has a consistent influence on combustion performance: the temperature peak was higher and nearer to burner, the radiation flux to combustor wall increased, and also the absorption and scattering coefficients of the combustion products increased. The effect of coal particle size distribution on absorption and scattering coefficients and wall heat flux is significant. But there is only a small effect on gas temperature and fuel fraction burned; it is speculated

  8. Optical image encryption based on phase retrieval combined with three-dimensional particle-like distribution

    International Nuclear Information System (INIS)

    Chen, Wen; Chen, Xudong; Sheppard, Colin J R

    2012-01-01

    We propose a new phase retrieval algorithm for optical image encryption in three-dimensional (3D) space. The two-dimensional (2D) plaintext is considered as a series of particles distributed in 3D space, and an iterative phase retrieval algorithm is developed to encrypt the series of particles into phase-only masks. The feasibility and effectiveness of the proposed method are demonstrated by a numerical experiment, and the advantages and security of the proposed optical cryptosystems are also analyzed and discussed. (paper)

  9. Log-Normal Distribution in a Growing System with Weighted and Multiplicatively Interacting Particles

    Science.gov (United States)

    Fujihara, Akihiro; Tanimoto, Satoshi; Yamamoto, Hiroshi; Ohtsuki, Toshiya

    2018-03-01

    A growing system with weighted and multiplicatively interacting particles is investigated. Each particle has a quantity that changes multiplicatively after a binary interaction, with its growth rate controlled by a weight parameter in a homogeneous symmetric kernel. We consider the system using moment inequalities and analytically derive the log-normal-type tail in the probability distribution function of quantities when the parameter is negative, which is different from the result for single-body multiplicative processes. We also find that the system approaches a winner-take-all state when the parameter is positive.

  10. Analysis of the dust particles distribution and ventilation as a way to improve indoor air quality

    Science.gov (United States)

    Kozlovtseva, E. Yu; Azarov, V. N.; Stefanenko, I. V.

    2017-10-01

    The indoor air pollution is analyzed in the article. The subject of the research is the presence and composition of the dust particles taken into “traps” in the working space of the public building (Volgograd State Technical University, Volgograd, the Russian Federation). The research has established the range of sizes of the particulate matter (fractional composition) for the dust in the air of the working space in the form of integral curves for the mass distribution of particles with to their diameters, it also provides the scheme of the air flows movement in the ventilation system of the room.

  11. Aerosol concentration and particle size distributions in underground excavations of a hard coal mine.

    Science.gov (United States)

    Skubacz, Krystian; Wojtecki, Łukasz; Urban, Paweł

    2017-09-01

    Deposition of aerosols in the respiratory system depends inter alia on their size and the respiratory tract deposition is appreciable for nanometer-sized particles. This article presents the results of measurements of size distributions of aerosols in the range of several nanometers up to about 20 μm in the underground mine excavations of an active hard coal mine. The study included practically all particles of a respirable fraction. The results showed that a high concentration of fine and ultrafine aerosols occurs in key underground workplaces especially during mining machine operations, although their contribution to total mass concentration is usually negligible.

  12. Particle transport in a wave spectrum with a thermal distribution of Larmor radii

    Science.gov (United States)

    Martinell, Julio; Kryukov, Nikolay; Del Castillo-Negrete, Diego

    2017-10-01

    Test particle E × B transport is studied due to an infinite spectrum of drift waves in two dimensions using a Hamiltonian approach, which can be reduced to a 2D mapping. Finite Larmor radius (FLR) effects are included taking a gyroaverage. When the wave amplitude is increased there is a gradual transition to chaos but the chaos level is reduced when FLR grows, implying that fast particles are better confined. The fraction of confined particles is found to be reduced as the wave amplitude rises. The statistical properties of transport are studied finding that, in the absence of a background flow, it is diffusive with a Gaussian PDF, when all particles have the same FLR. In contrast, for a thermal FLR distribution, the PDF is non-Gaussian but the transport remains diffusive. A theoretical explanation of this is given showing that a superposition of Gaussians produces a PDF with long tails. When a background flow is introduced that varies monotonically with radius, the transport becomes strongly super-diffusive due to the appearance of long Levy flights which dominate the particles. The PDF develops long tails as the flow strength is increased. The particle variance scales as σ t3 for chaotic regime but reduces to ballistic ( t2) for low chaos. Work funded by PAPIIT-UNAM project IN109115.

  13. [Size distributions of organic carbon and elemental carbon in Nanjing aerosol particles].

    Science.gov (United States)

    Wu, Meng-Long; Guo, Zhao-Bing; Liu, Feng-Ling; Liu, Jie; Lu, Xi; Jiang, Lin-Xian

    2014-02-01

    The concentrations and size distributions of organic carbon (OC) and elemental carbon (EC) in particles collected in Nanjing Normal University representing urban area and in Nanjing College of Chemical Technology standing for industrial area were analyzed using Model 2001A Thermal Optical Carbon Analyzer. The mass concentrations were the highest with the size below 0.43 microm in urban and industrial area. OC accounted for 20.9%, 21.9%, 29.6%, 27.9% respectively and those were 24.0%, 23.5%, 31.4%, 22.6% respectively for EC in the four seasons in urban area. In the industrial area, OC accounted for 18.6%, 45.8%, 26.6%, 25.9% respectively and the proportions of EC were 16.7%, 60.9%, 26.3%, 24.3% respectively. Overall, OC and EC were enriched in fine particles below 2.1 microm and they accounted for the highest proportion in summer in urban area while it did not show significant seasonal variation for industrial area. SOC in fine particles achieved high values in summer while the unobvious seasonal variation in coarse particles might be attributed to the contribution of different pollution sources and meteorological factors. Correlations and OC/EC ratio method implied that OC and EC mainly came from vehicles exhaust and coal combustion in fine particles while they were also related to biomass combustion and cooking in coarse particles.

  14. Effects of particle size distribution on some physical, chemical and functional properties of unripe banana flour.

    Science.gov (United States)

    Savlak, Nazlı; Türker, Burcu; Yeşilkanat, Nazlıcan

    2016-12-15

    The objective of this study was to examine the effect of particle size distribution on physical, chemical and functional properties of unripe banana flour for the first time. A pure triploid (AAA group) of Musa acuminata subgroup Cavendish (°Brix;0.2, pH;4.73, titratable acidity; 0.56g/100g malic acid, total solids; 27.42%) which was supplied from Gazipaşa, Antalya, Turkey from October 2014 to October 2015 was used. Size fractions of <212, 212-315, 316-500 and 501-700μm were characterized for their physical, functional and antioxidant properties. Particle size significantly effected color, water absorbtion index and wettability. L(∗) value decreased, a(∗) and b(∗) values decreased by increasing particle size (r(2)=-0.94, r(2)=0.72, r(2)=0.73 respectively). Particles under 212μm had the lowest rate of wettability (83.40s). A negative correlation between particle size and wettability (r(2)=-0.75) and positive correlation between particle size and water absorption index (r(2)=0.94) was observed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Particle number concentration, size distribution and chemical composition during haze and photochemical smog episodes in Shanghai.

    Science.gov (United States)

    Wang, Xuemei; Chen, Jianmin; Cheng, Tiantao; Zhang, Renyi; Wang, Xinming

    2014-09-01

    The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and photochemical smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibilitysmog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, photochemical smog and clean days were 102, 49, 15μm(3)/cm(3) and 949, 649, 206μm(2)/cm(3), respectively. As haze events got more severe, the number concentration of particles smaller than 50nm decreased, but the particles of 50-200nm and 0.5-1μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH4(+), SO4(2-) and NO3(-) increased greatly, followed by Na(+), K(+), Ca(2+) and Cl(-). These ions were very different in size-resolved particles during haze and photochemical smog episodes. Copyright © 2014. Published by Elsevier B.V.

  16. [Particle number size distribution near a major road with different traffic conditions].

    Science.gov (United States)

    Yang, Liu; Wu, Ye; Song, Shao-Jie; Hao, Ji-Ming

    2012-03-01

    The profiles of number concentration of ambient particles at a roadside site in Beijing were studied with different traffic conditions. A Scanning Mobility Particle Sizer (SMPS) was utilized to measure the number concentrations of fine and ultrafine (10-100 nm) particles in August 2008 and August 2009, which represented the normal and Olympic traffic conditions, respectively. Size distributions of particle number concentration were identified and their temporal variations were also discussed. Results indicated that with normal traffic pattern, the total number concentration of ultrafine and 10-478 nm particles were (1.15 +/- 0.49) x 10(4) cm(-3) and (1.61 +/- 0.57) x 10(4) cm(-3), respectively. While the concentrations were decreased to (0.55 +/- 0.14) x 10(4) cm(-3) and (1.21 +/- 0.24) x 10(4) cm(-3), respectively, with special traffic condition during the Beijing Olympic Games. Largest reduction of 52.2% was observed for ultrafine particles among all size ranges. With normal traffic condition, bimodal distribution was found with two peak values in number concentrations around 22.5 nm and 113.0 nm. During the Olympic period, nucleation mode particles were significantly reduced due to a series of temporal control measures on motor vehicles such as the removal of yellow-labeled vehicles from the roads and travel restrictions based on odd-even license plate numbers. As a result, the peak in particle number concentration at 22.5 nm disappeared. The temporal variation indicated that significantly higher ultrafine particle number concentrations occurred around 00 : 00-04 : 00, 11 : 00-13 : 00 and 17 : 00-20 : 00 with normal traffic situation, which primarily attributed to the contributions of diesel exhaust at night, secondary formation at noon and traffic jam in the evening, respectively. However during the Olympic period, the temporal variation pattern changed significantly. The gap in the number concentrations of ultrafine particle between these three time periods

  17. Measurement of resuspended aerosol in the Chernobyl area. Pt. 2. Size distribution of radioactive particles

    International Nuclear Information System (INIS)

    Garger, E.K.; Kashpur, V.; Paretzke, H.G.; Tschiersch, J.

    1998-01-01

    Size distribution measurements of particulate radionuclides were performed at two sites in the Chernobyl 30-km exclusion zone using several cascade impactors. The results obtained in the period September 1986 till June 1993 were discussed with regard to the general assumption of a log-normal activity size distribution in inhalation dose assessment. At Zapolie (a site 14 km from the Chernobyl reactor) a bimodal distribution was observed in 91% of all measured distributions. In most cases the medians were about 4 μm and in the range 20-30 μm. According to soil granulometric data this finding was explained by superimposing two processes: local resuspension and advective transport of radioactive aerosol from highly contaminated territories. The mean air concentration showed an increasing proportion of inhalable particles over the years since the accident. In 1993 the inhalable fraction was about 48% of the total concentration. At Pripyat, a site situated within a highly contaminated area, unimodal types of size distributions were predominant with the median diameters in the range 5-10 μm for 137 Cs. For the three nuclides 137 Cs, 144 Ce and 106 Ru, very similar types of distribution were observed. Apparently, the radioactive aerosol was of fuel origin. During a forest fire at a distance of 17 km, the majority of the radioactivity was associated with submicrometer particles with median diameters in the range 0.28-0.50 μm. (orig.)

  18. Spherical Harmonic Analysis of Particle Velocity Distribution Function: Comparison of Moments and Anisotropies using Cluster Data

    Science.gov (United States)

    Gurgiolo, Chris; Vinas, Adolfo F.

    2009-01-01

    This paper presents a spherical harmonic analysis of the plasma velocity distribution function using high-angular, energy, and time resolution Cluster data obtained from the PEACE spectrometer instrument to demonstrate how this analysis models the particle distribution function and its moments and anisotropies. The results show that spherical harmonic analysis produced a robust physical representation model of the velocity distribution function, resolving the main features of the measured distributions. From the spherical harmonic analysis, a minimum set of nine spectral coefficients was obtained from which the moment (up to the heat flux), anisotropy, and asymmetry calculations of the velocity distribution function were obtained. The spherical harmonic method provides a potentially effective "compression" technique that can be easily carried out onboard a spacecraft to determine the moments and anisotropies of the particle velocity distribution function for any species. These calculations were implemented using three different approaches, namely, the standard traditional integration, the spherical harmonic (SPH) spectral coefficients integration, and the singular value decomposition (SVD) on the spherical harmonic methods. A comparison among the various methods shows that both SPH and SVD approaches provide remarkable agreement with the standard moment integration method.

  19. Probing the particulate microstructure of the aerodynamic particle size distribution of dry powder inhaler combination products.

    Science.gov (United States)

    Jetzer, M W; Morrical, B D; Schneider, M; Edge, S; Imanidis, G

    2017-12-29

    The in-vitro aerosol performance of two combination dry powder inhaler (DPI) products, Foster ® NEXThaler ® and Seretide ® Diskus ® were investigated with single particle aerosol mass spectrometry (SPAMS). The in-vitro pharmaceutical performance is markedly different for both inhalers. Foster ® NEXThaler ® generates a higher fine particle fraction (FPF aerodynamic particle size distribution (APSD), it could be verified with SPAMS that overall Foster ® NEXThaler ® emits a significantly higher number of fine and extra fine particles with a median aerodynamic diameter (MAD) of 2.1 μm while Seretide ® Diskus ® had a larger MAD of 3.1 μm. Additionally, the interactions between the two active pharmaceutical ingredients (APIs) in both products are different. While Seretide ® Diskus ® emits a significant (37%) number of co-associated API particles, only a negligible number of co-associated API particles were found in Foster ® NEXThaler ® (<1%). A major difference with Foster ® NEXThaler ® is that it contains magnesium stearate (MgSt) as a second excipient besides lactose in a so-called 'dual excipient' platform. The data generated using SPAMS suggested that nearly all of the beclomethasone dipropionate particles in Foster ® NEXThaler ® also contain MgSt and must therefore be co-associated with this additional excipient. This may help explain why beclomethasone dipropionate in Foster ® NEXThaler ® forms less particle co-associations with the second API, formoterol fumarate, shows a lower cohesive strength in respect to beclomethasone itself and why both APIs exhibit superior detachment from the carrier as evidenced by the increased eFPF and smaller MAD. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Characterizations of particle size distribution of the droplets exhaled by sneeze.

    Science.gov (United States)

    Han, Z Y; Weng, W G; Huang, Q Y

    2013-11-06

    This work focuses on the size distribution of sneeze droplets exhaled immediately at mouth. Twenty healthy subjects participated in the experiment and 44 sneezes were measured by using a laser particle size analyser. Two types of distributions are observed: unimodal and bimodal. For each sneeze, the droplets exhaled at different time in the sneeze duration have the same distribution characteristics with good time stability. The volume-based size distributions of sneeze droplets can be represented by a lognormal distribution function, and the relationship between the distribution parameters and the physiological characteristics of the subjects are studied by using linear regression analysis. The geometric mean of the droplet size of all the subjects is 360.1 µm for unimodal distribution and 74.4 µm for bimodal distribution with geometric standard deviations of 1.5 and 1.7, respectively. For the two peaks of the bimodal distribution, the geometric mean (the geometric standard deviation) is 386.2 µm (1.8) for peak 1 and 72.0 µm (1.5) for peak 2. The influences of the measurement method, the limitations of the instrument, the evaporation effects of the droplets, the differences of biological dynamic mechanism and characteristics between sneeze and other respiratory activities are also discussed.

  1. The impact of mass transfer limitations on size distributions of particle associated SVOCs in outdoor and indoor environments

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Cong; Zhang, Yinping [Department of Building Science, Tsinghua University, Beijing (China); Weschler, Charles J., E-mail: weschlch@rwjms.rutgers.edu [Department of Building Science, Tsinghua University, Beijing (China); Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ (United States); International Center for Indoor Environment and Energy, Technical University of Denmark, Lyngby (Denmark)

    2014-11-01

    Semi-volatile organic compounds (SVOCs) partition between the gas phase and airborne particles. The size distribution of particle-associated SVOCs impacts their fate in outdoor and indoor environments, as well as human exposure to these compounds and subsequent health risks. Allen et al. (1996) previously proposed that the rate of mass transfer can impact polycyclic aromatic hydrocarbon (PAH) partitioning among different sized particles, especially for time scales relevant to urban aerosols. The present study quantitatively builds on this idea, presenting a model that incorporates dynamic SVOC/particle interaction and applying this model to typical outdoor and indoor scenarios. The model indicates that the impact of mass transfer limitations on the size distribution of a particle-associated SVOC can be evaluated by the ratio of the time to achieve gas–particle equilibrium relative to the residence time of particles. The higher this ratio, the greater the influence of mass transfer limitations on the size distribution of particle-associated SVOCs. The influence of such constraints is largest on the fraction of particle-associated SVOCs in the coarse mode (> 2 μm). Predictions from the model have been found to be in reasonable agreement with size distributions measured for PAHs at roadside and suburban locations in Japan. The model also quantitatively explains shifts in the size distributions of particle associated SVOCs compared to those for particle mass, and the manner in which these shifts vary with temperature and an SVOC's molecular weight. - Highlights: • Rate of mass transfer can impact SVOC partitioning among different sized particles. • Model was developed that incorporates dynamic SVOC/particle sorption. • Key parameters: mass-transfer coefficients, partition coefficient, residence time • Model explains observed SVOC size distribution shifts with temperature and MW. • Largest impact of mass transfer constraints: SVOC sorption to coarse

  2. High Deformability and Particle Size Distribution of Monodisperse Phytoglycogen Nanoparticles Revealed By Atomic Force Microscopy Imaging

    Science.gov (United States)

    Baylis, Benjamin; Dutcher, John

    We have used atomic force microscopy (AFM) imaging in water to determine the volume of hydrated monodisperse phytoglycogen nanoparticles adsorbed onto mica surfaces. By significantly reducing the interaction between the AFM tip and the ``sticky'' nanoparticles, we were able to obtain high quality images. We found that the adsorbed particles are highly deformed, forming pancake-like objects on the hydrophilic mica surface. By measuring the distribution of particle volumes, we calculated the average effective spherical radius of the hydrated particles, and compared this value with that measured in solution using small angle neutron scattering. These measurements illustrate the distinct advantages of AFM imaging over other imaging techniques, namely the ability to measure the height of objects in a liquid environment.

  3. On the spatial distribution and evolution of ultrafine particles in Barcelona

    Directory of Open Access Journals (Sweden)

    M. Dall'Osto

    2013-01-01

    Full Text Available Sources and evolution of ultrafine particles were investigated both horizontally and vertically in the large urban agglomerate of Barcelona, Spain. Within the SAPUSS project (Solving Aerosol Problems by Using Synergistic Strategies, a large number of instruments was deployed simultaneously at different monitoring sites (road, two urban background, regional background, urban tower 150 m a.s.l., urban background tower site 80 m a.s.l. during a 4 week period in September–October 2010. Particle number concentrations (N>5 nm are highly correlated with black carbon (BC at all sites only under strong vehicular traffic influences. By contrast, under cleaner atmospheric conditions (low condensation sink, CS such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. Size-resolved aerosol distributions (N10–500 as well as particle number concentrations (N>5 nm allow us to identify three types of nucleation and growth events: (1 a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding urban background area; (2 a regional type event impacting only the regional background area but not the urban agglomerate; (3 an urban type event which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the optimal combination between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated

  4. Variability of Particle Size Distributions in the Bohai Sea and the Yellow Sea

    Directory of Open Access Journals (Sweden)

    Zhongfeng Qiu

    2016-11-01

    Full Text Available Particle size distribution (PSD is an important parameter that is relevant to many aspects of marine ecosystems, such as phytoplankton functional types, optical absorption and scattering from particulates, sediment fluxes, and carbon export. However, only a handful of studies have documented the PSD variability in different regions. Here, we investigate the PSD properties and variability in two shallow and semi-enclosed seas (the Bohai Sea (BS and Yellow Sea (YS, using in situ laser diffraction measurements (LISST-100X Type C and other measurements at 79 stations in November 2013. The results show large variability in particle concentrations (in both volume and number concentrations, with volume concentrations varying by 57-fold. The median particle diameter (Dv50 from each of the water samples also covers a large range (22.4–307.0 μm and has an irregular statistical distribution, indicating complexity in the PSD. The PSD slopes (2.7–4.5, estimated from a power-law model, cover nearly the entire range reported previously for natural waters. Small mineral particles (with large PSD slopes are characteristic of near-shore waters prone to sediment resuspension by winds and tides, while large biological particles (with small PSD slopes dominate the total suspended particulates for waters away from the coast. For the BS and YS, this study provides the first report on the properties and spatial variability of the PSD, which may influence the optical properties of the ocean surface and remote sensing algorithms that are based on estimations of particle concentrations and sizes.

  5. Simulation and analysis of the soot particle size distribution in a turbulent nonpremixed flame

    KAUST Repository

    Lucchesi, Marco

    2017-02-05

    A modeling framework based on Direct Simulation Monte Carlo (DSMC) is employed to simulate the evolution of the soot particle size distribution in turbulent sooting flames. The stochastic reactor describes the evolution of soot in fluid parcels following Lagrangian trajectories in a turbulent flow field. The trajectories are sampled from a Direct Numerical Simulation (DNS) of a n-heptane turbulent nonpremixed flame. The DSMC method is validated against experimentally measured size distributions in laminar premixed flames and found to reproduce quantitatively the experimental results, including the appearance of the second mode at large aggregate sizes and the presence of a trough at mobility diameters in the range 3–8 nm. The model is then applied to the simulation of soot formation and growth in simplified configurations featuring a constant concentration of soot precursors and the evolution of the size distribution in time is found to depend on the intensity of the nucleation rate. Higher nucleation rates lead to a higher peak in number density and to the size distribution attaining its second mode sooner. The ensemble-averaged PSDF in the turbulent flame is computed from individual samples of the PSDF from large sets of Lagrangian trajectories. This statistical measure is equivalent to time-averaged, scanning mobility particle size (SMPS) measurements in turbulent flames. Although individual trajectories display strong bimodality as in laminar flames, the ensemble-average PSDF possesses only one mode and a long, broad tail, which implies significant polydispersity induced by turbulence. Our results agree very well with SMPS measurements available in the literature. Conditioning on key features of the trajectory, such as mixture fraction or radial locations does not reduce the scatter in the size distributions and the ensemble-averaged PSDF remains broad. The results highlight and explain the important role of turbulence in broadening the size distribution of

  6. A new multiple robot path planning algorithm: dynamic distributed particle swarm optimization.

    Science.gov (United States)

    Ayari, Asma; Bouamama, Sadok

    2017-01-01

    Multiple robot systems have become a major study concern in the field of robotic research. Their control becomes unreliable and even infeasible if the number of robots increases. In this paper, a new dynamic distributed particle swarm optimization (D 2 PSO) algorithm is proposed for trajectory path planning of multiple robots in order to find collision-free optimal path for each robot in the environment. The proposed approach consists in calculating two local optima detectors, LOD pBest and LOD gBest . Particles which are unable to improve their personal best and global best for predefined number of successive iterations would be replaced with restructured ones. Stagnation and local optima problems would be avoided by adding diversity to the population, without losing the fast convergence characteristic of PSO. Experiments with multiple robots are provided and proved effectiveness of such approach compared with the distributed PSO.

  7. Optical cryptography topology based on a three-dimensional particle-like distribution and diffractive imaging.

    Science.gov (United States)

    Chen, Wen; Chen, Xudong

    2011-05-09

    In recent years, coherent diffractive imaging has been considered as a promising alternative for information retrieval instead of conventional interference methods. Coherent diffractive imaging using the X-ray light source has opened up a new research perspective for the measurement of non-crystalline and biological specimens, and can achieve unprecedentedly high resolutions. In this paper, we show how a three-dimensional (3D) particle-like distribution and coherent diffractive imaging can be applied for a study of optical cryptography. An optical multiple-random-phase-mask encoding approach is used, and the plaintext is considered as a series of particles distributed in a 3D space. A topology concept is also introduced into the proposed optical cryptosystem. During image decryption, a retrieval algorithm is developed to extract the plaintext from the ciphertexts. In addition, security and advantages of the proposed optical cryptography topology are also analyzed. © 2011 Optical Society of America

  8. Stratospheric aerosol particle size distribution based on multi-color polarization measurements of the twilight sky

    Science.gov (United States)

    Ugolnikov, Oleg S.; Maslov, Igor A.

    2018-03-01

    Polarization measurements of the twilight background with Wide-Angle Polarization Camera (WAPC) are used to detect the depolarization effect caused by stratospheric aerosol near the altitude of 20 km. Based on a number of observations in central Russia in spring and summer 2016, we found the parameters of lognormal size distribution of aerosol particles. This confirmed the previously published results of the colorimetric method as applied to the same twilights. The mean particle radius (about 0.1 micrometers) and size distribution are also in agreement with the recent data of in situ and space-based remote sensing of stratospheric aerosol. Methods considered here provide two independent techniques of the stratospheric aerosol study based on the twilight sky analysis.

  9. Localization of WSN using Distributed Particle Swarm Optimization algorithm with precise references

    Science.gov (United States)

    Janapati, Ravi Chander; Balaswamy, Ch.; Soundararajan, K.

    2016-08-01

    Localization is the key research area in Wireless Sensor Networks. Finding the exact position of the node is known as localization. Different algorithms have been proposed. Here we consider a cooperative localization algorithm with censoring schemes using Crammer Rao Bound (CRB). This censoring scheme can improve the positioning accuracy and reduces computation complexity, traffic and latency. Particle swarm optimization (PSO) is a population based search algorithm based on the swarm intelligence like social behavior of birds, bees or a school of fishes. To improve the algorithm efficiency and localization precision, this paper presents an objective function based on the normal distribution of ranging error and a method of obtaining the search space of particles. In this paper Distributed localization algorithm PSO with CRB is proposed. Proposed method shows better results in terms of position accuracy, latency and complexity.

  10. Single-Particle Momentum Distributions of Efimov States in Mixed-Species Systems

    DEFF Research Database (Denmark)

    T. Yamashita, M.; F. Bellotti, F.; Frederico, T.

    2013-01-01

    to derive formulas for the scaling factor of the Efimov spectrum for any mass ratio assuming either that two or three of the two-body subsystems have a bound state at zero energy. We consider the single-particle momentum distribution analytically and numerically and analyse the tail of the momentum......We solve the three-body bound state problem in three dimensions for mass imbalanced systems of two identical bosons and a third particle in the universal limit where the interactions are assumed to be of zero-range. The system displays the Efimov effect and we use the momentum-space wave equation...... distribution to obtain the three-body contact parameter. Our finding demonstrate that the functional form of the three-body contact term depends on the mass ratio and we obtain an analytic expression for this behavior. To exemplify our results, we consider mixtures of Lithium with either two Caesium or Rubium...

  11. Questionnaire-based survey on the distribution and incidence of canine babesiosis in countries of Western Europe

    Directory of Open Access Journals (Sweden)

    Halos Lénaïg

    2014-01-01

    Full Text Available The incidence of canine babesiosis may vary considerably from one country to another depending on the distribution of the causative parasite species and their specific vectors. The aim of the present study was to evaluate the clinical occurrence of canine babesiosis diagnosed in European veterinary clinics and propose an updated map of the disease distribution in Western Europe. Questionnaires were sent to companion animal veterinary clinics in Spain, France, Benelux, Germany and Austria. The annual number of babesiosis cases in 2010, the number of practitioners in the clinic and the location of the clinic were recorded. The total numbers of dogs and practitioners in each country were used for definition of the reference populations and the annual incidence of canine babesiosis was calculated by dividing the total number of reported babesiosis cases by the total number of dogs in the veterinary practices involved in the study. Data were georeferenced for distribution map construction. The overall annual incidence of clinical babesiosis amongst the investigated dog population was 0.7%, with significant variations amongst countries and regions. Three epidemiological situations were described: (i Spain, with co-existence of several species of piroplasms and patchy distribution of babesiosis, (ii France, with overall presence of babesiosis due to Babesia canis and local variations and (iii Benelux, Germany and Austria, with overall low prevalence of the disease associated with localised description related either to imported cases or to small autochthonous foci of B. canis infection.

  12. Nodular corrosion resistance of zircaloy-2 in relation to second-phase particle distribution

    International Nuclear Information System (INIS)

    Andersson, T.; Thorvaldsson, T.

    1987-01-01

    A large number of Zircaloy-2 standard tube lots and tube lots beta-quenched in intermediate size were corrosion tested in steam at 490 to 515 0 C. In addition, specimens heat treated in the temperature range 675 to 850 0 C were corrosion tested in steam at 500 0 C. To study the correlation between nodular corrosion susceptibility and type and size distribution of second phases, specimens from one beta-quenched and two standard tube lots, one with high resistance and one with low resistance to nodular corrosion, were examined by optical and electron microscopy. In addition, specimens from the heat treatment program were studied in order to investigate heat treatment effects. For quantitative analysis, a JEOL 200 CX scanning transmission electron microscope (STEM) equipped with a Link Systems energy dispersive X-ray spectrometer (EDX) was used. The STEM studies showed that two main types of second phases exist irrespective of heat treatment. These are hexagonal Zr(Cr,Fe) 2 and tetragonal Zr 2 (Ni,Fe). Of the different microstructural features studied, the size distribution of particles was found to be the main factor distinguishing the different materials. In the low susceptibility standard tube lot, the particles were smaller than in the high susceptibility lot. The smallest particles were found in the beta-quenched lot, where no particles coarser than about 0.2 μm could be seen

  13. The new PARIOTM device for determining continuous particle-size distributions of soils and sediments.

    Science.gov (United States)

    Miller, Alina; Pertassek, Thomas; Steins, Andreas; Durner, Wolfgang; Göttlein, Axel; Petrik, Wolfgang; von Unold, Georg

    2017-04-01

    The particle-size distribution (PSD) is a key property of soils. The reference method for determining the PSD is based on gravitational sedimentation of particles in an initially homogeneous suspension. Traditional methods measure manually (i) the uplift of a floating body in the suspension at different times (Hydrometer method) or (ii) the mass of solids in extracted suspension aliquots at predefined sampling depths and times (Pipette method). Both methods lead to a disturbance of the sedimentation process and provide only discrete data of the PSD. Durner et al. (2017) recently developed a new automated method to determine particle-size distributions of soils and sediments from gravitational sedimentation (Durner, W., S.C. Iden, and G. von Unold: The integral suspension pressure method (ISP) for precise particle-size analysis by gravitational sedimentation, Water Resources Research, doi:10.1002/2016WR019830, 2017). The so-called integral suspension method (ISP) method estimates continuous PSD's from sedimentation experiments by recording the temporal evolution of the suspension pressure at a certain measurement depth in a sedimentation cylinder. It requires no manual interaction after start and thus no specialized training of the lab personnel and avoids any disturbance of the sedimentation process. The required technology to perform these experiments was developed by the UMS company, Munich and is now available as an instrument called PARIO, traded by the METER Group. In this poster, the basic functioning of PARIO is shown and key components and parameters of the technology are explained.

  14. An inverse modeling procedure to determine particle growth and nucleation rates from measured aerosol size distributions

    Directory of Open Access Journals (Sweden)

    B. Verheggen

    2006-01-01

    Full Text Available Classical nucleation theory is unable to explain the ubiquity of nucleation events observed in the atmosphere. This shows a need for an empirical determination of the nucleation rate. Here we present a novel inverse modeling procedure to determine particle nucleation and growth rates based on consecutive measurements of the aerosol size distribution. The particle growth rate is determined by regression analysis of the measured change in the aerosol size distribution over time, taking into account the effects of processes such as coagulation, deposition and/or dilution. This allows the growth rate to be determined with a higher time-resolution than can be deduced from inspecting contour plots ('banana-plots''. Knowing the growth rate as a function of time enables the evaluation of the time of nucleation of measured particles of a certain size. The nucleation rate is then obtained by integrating the particle losses from time of measurement to time of nucleation. The regression analysis can also be used to determine or verify the optimum value of other parameters of interest, such as the wall loss or coagulation rate constants. As an example, the method is applied to smog chamber measurements. This program offers a powerful interpretive tool to study empirical aerosol population dynamics in general, and nucleation and growth in particular.

  15. Angular distribution of sputtered particles measured by quartz crystal microbalances and Auger electron spectroscopy

    International Nuclear Information System (INIS)

    Taglauer, E.; Onsgaard, J.

    1986-01-01

    A method for measuring angular distributions of sputtered particles in situ under ultrahigh vacuum conditions has been developed. It is based on a simultaneous collection of the ejected atoms on a number of quartz crystal microbalances (QCM's), arranged in a semicircular pattern. Furthermore, it is possible to monitor the chemical state of the surface of the QCM's and to register the amount of deposited material by means of Auger electron spectroscopy. By this method the time evolution of the angular distribution can be followed from quartz crystal coverages in the submonolayer regime to depositions corresponding to many monolayers

  16. Mie forward scattering - Improved semiempirical approximation with application to particle size distribution inversion

    Science.gov (United States)

    Fymat, A. L.; Mease, K. D.

    1981-01-01

    The approximation of Penndorf (1962) and Shifrin-Punina (1968) to the Mie solution at forward scattering angles are extended to small size parameters. The proposed semiempirical approximation accurately represents the Mie results down to x = 0.5-1 for refractive index m = 1.33, and to x = 2.0 for larger index values. The implications of the result for the inversion of particle size distribution from single scattering data in the forward direction are discussed.

  17. Effect of particle size distribution and concentration on flow behavior of dense slurries

    Czech Academy of Sciences Publication Activity Database

    Vlasák, Pavel; Chára, Zdeněk

    2011-01-01

    Roč. 29, č. 1 (2011), s. 53-65 ISSN 0272-6351 R&D Projects: GA ČR(CZ) GAP105/10/1574 Institutional research plan: CEZ:AV0Z20600510 Keywords : concentration effect * dense complex slurry * experimental investigation * flow behavior * particle size distribution effect * pressure drop Subject RIV: BK - Fluid Dynamics Impact factor: 0.545, year: 2011

  18. The frictional properties of a simulated gouge having a fractal particle distribution

    Science.gov (United States)

    Biegel, R.L.; Sammis, C.G.; Dieterich, J.H.

    1989-01-01

    The frictional properties of a layer of simulated Westerly granite fault gouge sandwiched between sliding blocks of Westerly granite have been measured in a high-speed servo-controlled double-direct shear apparatus. Most gouge layers were prepared to have a self-similar particle distribution with a fractal dimension of 2.6. The upper fractal limit was varied between 45 and 710 ??m. Some gouges were prepared with all particles in the range between 360 and 710 ??m. In each experiment the sliding velocity was cyclically alternated between 1 and 10 ??ms-1 and the coefficient of friction ??m and its transient parameters a, b and Dc were measured as functions of displacement. In addition to the particle size distribution, the following experimental variables were also investigated: the layer thickness (1 and 3 mm), the roughness of the sliding surfaces (Nos 60 and 600 grit) and the normal stress (10 and 25 MPa). Some of the sample assemblies were epoxy impregnated following a run so the gouge structure could be microscopically examined in thin section. We observed that gouges which were initially non-fractal evolved to a fractal distribution with dimension 2.6. Gouges which had an initial fractal distribution remained fractal. When the sliding blocks had smooth surfaces, the coefficient of friction was relatively low and was independent of the particle distribution. In these cases, strong velocity weakening was observed throughout the experiment and the transient parameters a, b and Dc, remained almost constant. When the sliding blocks had rough surfaces, the coefficient of friction was larger and more dependent on the particle distribution. Velocity strengthening was observed initially but evolved to velocity weakening with increased sliding displacement. All three transient parameters changed with increasing displacement. The a and b values were about three times as large for rough surfaces as for smooth. The characteristic displacement Dc was not sensitive to surface

  19. Pesticides in the atmosphere: a comparison of gas-particle partitioning and particle size distribution of legacy and current-use pesticides

    Science.gov (United States)

    Degrendele, C.; Okonski, K.; Melymuk, L.; Landlová, L.; Kukučka, P.; Audy, O.; Kohoutek, J.; Čupr, P.; Klánová, J.

    2016-02-01

    This study presents a comparison of seasonal variation, gas-particle partitioning, and particle-phase size distribution of organochlorine pesticides (OCPs) and current-use pesticides (CUPs) in air. Two years (2012/2013) of weekly air samples were collected at a background site in the Czech Republic using a high-volume air sampler. To study the particle-phase size distribution, air samples were also collected at an urban and rural site in the area of Brno, Czech Republic, using a cascade impactor separating atmospheric particulates according to six size fractions. Major differences were found in the atmospheric distribution of OCPs and CUPs. The atmospheric concentrations of CUPs were driven by agricultural activities while secondary sources such as volatilization from surfaces governed the atmospheric concentrations of OCPs. Moreover, clear differences were observed in gas-particle partitioning; CUP partitioning was influenced by adsorption onto mineral surfaces while OCPs were mainly partitioning to aerosols through absorption. A predictive method for estimating the gas-particle partitioning has been derived and is proposed for polar and non-polar pesticides. Finally, while OCPs and the majority of CUPs were largely found on fine particles, four CUPs (carbendazim, isoproturon, prochloraz, and terbuthylazine) had higher concentrations on coarse particles ( > 3.0 µm), which may be related to the pesticide application technique. This finding is particularly important and should be further investigated given that large particles result in lower risks from inhalation (regardless the toxicity of the pesticide) and lower potential for long-range atmospheric transport.

  20. Differentiating gold nanorod samples using particle size and shape distributions from transmission electron microscope images

    Science.gov (United States)

    Grulke, Eric A.; Wu, Xiaochun; Ji, Yinglu; Buhr, Egbert; Yamamoto, Kazuhiro; Song, Nam Woong; Stefaniak, Aleksandr B.; Schwegler-Berry, Diane; Burchett, Woodrow W.; Lambert, Joshua; Stromberg, Arnold J.

    2018-04-01

    Size and shape distributions of gold nanorod samples are critical to their physico-chemical properties, especially their longitudinal surface plasmon resonance. This interlaboratory comparison study developed methods for measuring and evaluating size and shape distributions for gold nanorod samples using transmission electron microscopy (TEM) images. The objective was to determine whether two different samples, which had different performance attributes in their application, were different with respect to their size and/or shape descriptor distributions. Touching particles in the captured images were identified using a ruggedness shape descriptor. Nanorods could be distinguished from nanocubes using an elongational shape descriptor. A non-parametric statistical test showed that cumulative distributions of an elongational shape descriptor, that is, the aspect ratio, were statistically different between the two samples for all laboratories. While the scale parameters of size and shape distributions were similar for both samples, the width parameters of size and shape distributions were statistically different. This protocol fulfills an important need for a standardized approach to measure gold nanorod size and shape distributions for applications in which quantitative measurements and comparisons are important. Furthermore, the validated protocol workflow can be automated, thus providing consistent and rapid measurements of nanorod size and shape distributions for researchers, regulatory agencies, and industry.

  1. Applying sequential Monte Carlo methods into a distributed hydrologic model: lagged particle filtering approach with regularization

    Directory of Open Access Journals (Sweden)

    S. J. Noh

    2011-10-01

    Full Text Available Data assimilation techniques have received growing attention due to their capability to improve prediction. Among various data assimilation techniques, sequential Monte Carlo (SMC methods, known as "particle filters", are a Bayesian learning process that has the capability to handle non-linear and non-Gaussian state-space models. In this paper, we propose an improved particle filtering approach to consider different response times of internal state variables in a hydrologic model. The proposed method adopts a lagged filtering approach to aggregate model response until the uncertainty of each hydrologic process is propagated. The regularization with an additional move step based on the Markov chain Monte Carlo (MCMC methods is also implemented to preserve sample diversity under the lagged filtering approach. A distributed hydrologic model, water and energy transfer processes (WEP, is implemented for the sequential data assimilation through the updating of state variables. The lagged regularized particle filter (LRPF and the sequential importance resampling (SIR particle filter are implemented for hindcasting of streamflow at the Katsura catchment, Japan. Control state variables for filtering are soil moisture content and overland flow. Streamflow measurements are used for data assimilation. LRPF shows consistent forecasts regardless of the process noise assumption, while SIR has different values of optimal process noise and shows sensitive variation of confidential intervals, depending on the process noise. Improvement of LRPF forecasts compared to SIR is particularly found for rapidly varied high flows due to preservation of sample diversity from the kernel, even if particle impoverishment takes place.

  2. Considerations on the determining factors of the angular distribution of emitted particles in laser ablation

    International Nuclear Information System (INIS)

    Konomi, I.; Motohiro, T.; Kobayashi, T.; Asaoka, T.

    2010-01-01

    Simulations of particles which are emitted in laser ablation have been performed by the method of Direct Simulation Monte Carlo to investigate the deposition profiles of the emitted particles. The influences of the temperature, pressure and stream velocity of the initial evaporated layer formed during laser ablation process on the profile of the deposited film have been examined. It is found that the temperature gives a minor influence on the deposition profile, whereas the stream velocity and the pressure of the initial evaporated layer have a greater impact on the deposition profile. The energy in the direction of surface normal (E perpendicular ) and that in the parallel direction of the surface (E || ) are shown to increase and decrease, respectively after the laser irradiation due to collisions between the emitted particles, and this trend is magnified as the pressure increases. As a consequence, the stream velocity in the direction of surface normal increases with the increase in the pressure. A mechanism of the phenomenon that a metal with a lower sublimation energy shows a broader angular distribution of emitted particles is presented. It is suggested that low density of evaporated layer of a metal with a low sublimation energy at its melting point decreases the number of collisions in the layer, leading to the low stream velocity in the direction of surface normal, which results in the broader deposition profile of the emitted particles.

  3. Particle size distribution of rice flour affecting the starch enzymatic hydrolysis and hydration properties.

    Science.gov (United States)

    de la Hera, Esther; Gomez, Manuel; Rosell, Cristina M

    2013-10-15

    Rice flour is becoming very attractive as raw material, but there is lack of information about the influence of particle size on its functional properties and starch digestibility. This study evaluates the degree of dependence of the rice flour functional properties, mainly derived from starch behavior, with the particle size distribution. Hydration properties of flours and gels and starch enzymatic hydrolysis of individual fractions were assessed. Particle size heterogeneity on rice flour significantly affected functional properties and starch features, at room temperature and also after gelatinization; and the extent of that effect was grain type dependent. Particle size heterogeneity on rice flour induces different pattern in starch enzymatic hydrolysis, with the long grain having slower hydrolysis as indicated the rate constant (k). No correlation between starch digestibility and hydration properties or the protein content was observed. It seems that in intact granules interactions with other grain components must be taken into account. Overall, particle size fractionation of rice flour might be advisable for selecting specific physico-chemical properties. Copyright © 2013. Published by Elsevier Ltd.

  4. Winter precipitation particle size distribution measurement by Multi-Angle Snowflake Camera

    Science.gov (United States)

    Huang, Gwo-Jong; Kleinkort, Cameron; Bringi, V. N.; Notaroš, Branislav M.

    2017-12-01

    From the radar meteorology viewpoint, the most important properties for quantitative precipitation estimation of winter events are 3D shape, size, and mass of precipitation particles, as well as the particle size distribution (PSD). In order to measure these properties precisely, optical instruments may be the best choice. The Multi-Angle Snowflake Camera (MASC) is a relatively new instrument equipped with three high-resolution cameras to capture the winter precipitation particle images from three non-parallel angles, in addition to measuring the particle fall speed using two pairs of infrared motion sensors. However, the results from the MASC so far are usually presented as monthly or seasonally, and particle sizes are given as histograms, no previous studies have used the MASC for a single storm study, and no researchers use MASC to measure the PSD. We propose the methodology for obtaining the winter precipitation PSD measured by the MASC, and present and discuss the development, implementation, and application of the new technique for PSD computation based on MASC images. Overall, this is the first study of the MASC-based PSD. We present PSD MASC experiments and results for segments of two snow events to demonstrate the performance of our PSD algorithm. The results show that the self-consistency of the MASC measured single-camera PSDs is good. To cross-validate PSD measurements, we compare MASC mean PSD (averaged over three cameras) with the collocated 2D Video Disdrometer, and observe good agreements of the two sets of results.

  5. Effect of Pressurized Metered Dose Inhaler Spray Characteristics and Particle Size Distribution on Drug Delivery Efficiency.

    Science.gov (United States)

    Yousefi, Morteza; Inthavong, Kiao; Tu, Jiyuan

    2017-10-01

    A key issue in pulmonary drug delivery is improvement of the delivery device for effective and targeted treatment. Pressurized metered dose inhalers (pMDIs) are the most popular aerosol therapy device for treating lung diseases. This article studies the effect of spray characteristics: injection velocity, spray cone angle, particle size distribution (PSD), and its mass median aerodynamic diameter (MMAD) on drug delivery. An idealized oral airway geometry, extending from mouth to the main bronchus, was connected to a pMDI device. Inhalation flow rates of 15, 30, and 60 L/min were used and drug particle tracking was a one-way coupled Lagrangian model. The results showed that most particles deposited in the pharynx, where the airway has a reduced cross-sectional area. Particle deposition generally decreased with initial spray velocity and with increased spray cone angle for 30 and 60 L/min flow rates. However, for 15 L/min flow rate, the deposition increased slightly with an increase in the spray velocity and cone angle. The effect of spray cone angle was more significant than the initial spray velocity on particle deposition. When the MMAD of a PSD was reduced, the deposition efficiency also reduces, suggesting greater rates of particle entry into the lung. The deposition rate showed negligible change when the MMAD was more than 8 μm. Spray injection angle and velocity change the drug delivery efficacy; however, the efficiency shows more sensitivity to the injection angle. The 30 L/min airflow rate delivers spray particles to the lung more efficiently than 15 and 60 L/min airflow rate, and reducing MMAD can help increase drug delivery to the lung.

  6. Influences of food hardness on the particle size distribution of food boluses.

    Science.gov (United States)

    Chen, Jianshe; Khandelwal, Niharika; Liu, Zhenyu; Funami, Takahiro

    2013-03-01

    Bolus swallowing or deglutition is a vital oral action which transports orally processed food from the oral cavity to the stomach for further digestion. Swallowing is routine to most health individuals, but it could be highly hazardous to many elderly and dysphagia patients. In order to provide proper food for safe consumption by these disadvantaged populations, a fundamental understanding of how bolus swallowing is triggered and is based on what criteria is urgently needed. Main objective of this work was to understand the physical properties of food boluses, in particular the bolus particle size distribution in relation to the hardness of the food. Food samples were chewed in free style by subjects and boluses were expectorated when subjects felt they were ready to be swallowed. Altogether seven different types of food were used and 10 health subjects participated in this study. Bolus particles were carefully washed and spread out on a flat surface. Images of bolus particles were taken using a digital camera and analysed using Image Pro Plus software for particle size quantification. Food hardness was measured using a Texture Analyser by a puncture test. It was observed that bolus particle size decreased with the increase of food hardness. The correlation between the two properties can be described by a power-law relationship. This relationship was also found applicable to literature results reported by Peyron et al. and Jalabert-Malbos et al. Food hardness has a direct influence on its bolus particle size. The harder the food, the smaller the bolus particle size. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  7. A Modelling Approach on Fine Particle Spatial Distribution for Street Canyons in Asian Residential Community

    Science.gov (United States)

    Ling, Hong; Lung, Shih-Chun Candice; Uhrner, Ulrich

    2016-04-01

    Rapidly increasing urban pollution poses severe health risks.Especially fine particles pollution is considered to be closely related to respiratory and cardiovascular disease. In this work, ambient fine particles are studied in street canyons of a typical Asian residential community using a computational fluid dynamics (CFD) dispersion modelling approach. The community is characterised by an artery road with a busy traffic flow of about 4000 light vehicles (mainly cars and motorcycles) per hour at rush hours, three streets with hundreds light vehicles per hour at rush hours and several small lanes with less traffic. The objective is to study the spatial distribution of the ambient fine particle concentrations within micro-environments, in order to assess fine particle exposure of the people living in the community. The GRAL modelling system is used to simulate and assess the emission and dispersion of the traffic-related fine particles within the community. Traffic emission factors and traffic situation is assigned using both field observation and local emissions inventory data. High resolution digital elevation data (DEM) and building height data are used to resolve the topographical features. Air quality monitoring and mobile monitoring within the community is used to validate the simulation results. By using this modelling approach, the dispersion of fine particles in street canyons is simulated; the impact of wind condition and street orientation are investigated; the contributions of car and motorcycle emissions are quantified respectively; the residents' exposure level of fine particles is assessed. The study is funded by "Taiwan Megacity Environmental Research (II)-chemistry and environmental impacts of boundary layer aerosols (Year 2-3) (103-2111-M-001-001-); Spatial variability and organic markers of aerosols (Year 3)(104-2111-M-001 -005 -)"

  8. Introducing a distributed unstructured mesh into gyrokinetic particle-in-cell code, XGC

    Science.gov (United States)

    Yoon, Eisung; Shephard, Mark; Seol, E. Seegyoung; Kalyanaraman, Kaushik

    2017-10-01

    XGC has shown good scalability for large leadership supercomputers. The current production version uses a copy of the entire unstructured finite element mesh on every MPI rank. Although an obvious scalability issue if the mesh sizes are to be dramatically increased, the current approach is also not optimal with respect to data locality of particles and mesh information. To address these issues we have initiated the development of a distributed mesh PIC method. This approach directly addresses the base scalability issue with respect to mesh size and, through the use of a mesh entity centric view of the particle mesh relationship, provides opportunities to address data locality needs of many core and GPU supported heterogeneous systems. The parallel mesh PIC capabilities are being built on the Parallel Unstructured Mesh Infrastructure (PUMI). The presentation will first overview the form of mesh distribution used and indicate the structures and functions used to support the mesh, the particles and their interaction. Attention will then focus on the node-level optimizations being carried out to ensure performant operation of all PIC operations on the distributed mesh. Partnership for Edge Physics Simulation (EPSI) Grant No. DE-SC0008449 and Center for Extended Magnetohydrodynamic Modeling (CEMM) Grant No. DE-SC0006618.

  9. Rapid detection of lactobacillus and yeast concentrations using a particle size distribution analyser.

    Science.gov (United States)

    Kim, H; Park, K; Oh, S; Chang, I S

    2009-11-01

    To see the possibility of particle size distribution analyser (PSDA) in detecting concentration of lactobacillus contaminants in yeast fermentation. A PSDA was used to rapidly determine the size and concentration of lactobacillus and Saccharomyces cerevisiae. Data showed that the aerodynamic diameters of Lactobacillus casei and S. cerevisiae cells were around 0.63 and 2.9 microm, respectively, with both cultures showing a linear relationship between cell density and particle count on a size distribution curve of PSDA. In addition, Lactobacillus fermentum showed high similarity in bacterial size distribution and particle count numbers with L. casei. The PSDA also rapidly detected (within 1 min) the cell concentrations of S. cerevisiae and L. casei in a mixed sample with different concentration ratios with 10(7)-10(9) cells ml(-1) of detection range. PSDA was demonstrated to be useful for the rapid detection of lactobacillus and S. cerevisiae concentrations. This is the first report concerning PSDA to detect the concentration of bacteria and yeast. This method can be useful in the actual field during ethanol fermentation because of relatively easy handling and rapid detection.

  10. The size distribution of marine atmospheric aerosol with regard to primary biological aerosol particles over the South Atlantic Ocean

    Science.gov (United States)

    Matthias-Maser, Sabine; Brinkmann, Jutta; Schneider, Wilhelm

    The marine atmosphere is characterized by particles which originate from the ocean and by those which reached the air by advection from the continent. The bubble-burst mechanism produces both sea salt as well as biological particles. The following article describes the determination of the size distribution of marine aerosol particles with special emphasis on the biological particles. Th data were obtained on three cruises with the German Research Vessel "METEOR" crossing the South Atlantic Ocean. The measurements showed that biological particles amount to 17% in number and 10% in volume concentration. Another type of particle became obvious in the marine atmosphere, the biologically contaminated particle, i.e. particles which consist partly (approximately up to one-third) of biological matter. Their concentration in the evaluated size class ( r>2 μm) is higher than the concentration of the pure biological particles. The concentrations vary over about one to two orders of magnitude during all cruises.

  11. Differences in particle size distributions collected by two wood dust samplers: preliminary findings

    International Nuclear Information System (INIS)

    Campopiano, A.; Olori, A.; Basili, F.; Ramires, D.; Zakrzewska, A.M.

    2008-01-01

    The International Agency for Research on Cancer (IARC) classification of wood dust as carcinogenic to humans, and the threshold limit value (TLV) of 5 mg/m 3 weighted over an 8-hour work day as defined by Italian legislation, have raised the issue of dust risk assessments in all woodworking environments. The aim is to characterize the particle size distribution for wood particles collected by two samplers used for collecting the inhalable fraction: the IOM sampler (Institute of Occupational Medicine, Edinburgh, Scotland) and the conical sampler also known in Italy as conetto. These two sampling heads were chosen mainly because the Italian conical sampler, used in the past for total dust sampling, is the most widely used by the Italian Prevention Services and analysis laboratories in general, whereas the IOM sampler was specifically designed to collect the inhalable fraction of airborne particles. The devices were placed side by side within the worker's breathing zone. In addition, another IOM sampler not connected to the personal sampling pump was placed on the same worker, thus functioning as a passive sampler capable of collecting projectile particles normally produced during processing. A Scanning Electron Microscope (SEM) coupled with energy dispersive X-ray spectrometry (EDAX) was used to count the number of particles collected on the sampling filters. The size of each particle identified by the SEM was determined by measuring its mean diameter. The SEM analysis revealed that the average size of the largest particles collected by the conetto sampler did not exceed 150 μm, whereas the size of particles collected by the IOM sampler was up to 350 μm. Indeed, the analysis of the filters of the passive IOM samplers showed that particles with mean diameters larger than 100 μm were collected, although the calculated percentage was very low (on average, approximately 1%). This does not mean that their gravimetric contribution is negligible; indeed, the weight of

  12. Mobility particle size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions

    Directory of Open Access Journals (Sweden)

    A. Wiedensohler

    2012-03-01

    Full Text Available Mobility particle size spectrometers often referred to as DMPS (Differential Mobility Particle Sizers or SMPS (Scanning Mobility Particle Sizers have found a wide range of applications in atmospheric aerosol research. However, comparability of measurements conducted world-wide is hampered by lack of generally accepted technical standards and guidelines with respect to the instrumental set-up, measurement mode, data evaluation as well as quality control. Technical standards were developed for a minimum requirement of mobility size spectrometry to perform long-term atmospheric aerosol measurements. Technical recommendations include continuous monitoring of flow rates, temperature, pressure, and relative humidity for the sheath and sample air in the differential mobility analyzer.

    We compared commercial and custom-made inversion routines to calculate the particle number size distributions from the measured electrical mobility distribution. All inversion routines are comparable within few per cent uncertainty for a given set of raw data.

    Furthermore, this work summarizes the results from several instrument intercomparison workshops conducted within the European infrastructure project EUSAAR (European Supersites for Atmospheric Aerosol Research and ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network to determine present uncertainties especially of custom-built mobility particle size spectrometers. Under controlled laboratory conditions, the particle number size distributions from 20 to 200 nm determined by mobility particle size spectrometers of different design are within an uncertainty range of around ±10% after correcting internal particle losses, while below and above this size range the discrepancies increased. For particles larger than 200 nm, the uncertainty range increased to 30%, which could not be explained. The network reference mobility spectrometers with identical design agreed within ±4% in the

  13. [Spatial Distribution of Stable Isotopes in Particle Organic Matters and Sediments from Baishi Reservoirs].

    Science.gov (United States)

    Guo, Kai; Zhao, Wen; Wang, Shan; Dai, Yu-xin; Zhang, Rong-kun; Li, Dong-ming

    2015-12-01

    Water quality and spatial distribution of stable isotopes in particle organic matters and sediments from Baishi reservoirs were produced in October, 2013. The results revealed that the average concentration of POC, TP and TN were (1.76 ± 0.98), (0.04 ± 0.03) and (1.80 ± 0.08) mg · L⁻¹, respectively. In different water depths, the concentrations of POC and TN in surface were higher than those in deep layer, but the concentration of TP was opposite. The concentrations of POC and TP were reduced gradually from upstream to downstream, but the concentration of TN had no obvious change in horizontal distribution. The δ¹³C and δ ¹⁵N values of small particle organic matters were (-24.6 ± 0.9) per thousand and (4.8 ± 0.4) per thousand, the δ¹³C and δ¹⁵N values of large particle organic matters were (-22.5 ± 0.9) per thousand and (6.7 ± 0.5) per thousand, both of which exhibited significant fluctuations. With the δ¹³C and δ¹⁵N values in small particle organic matters were different between each other of 4.6 per thousand and 2.7 per thousand, and those in large particle organic matters were different between each other of 3.3 per thousand and 1.8 per thousand. The δ¹³C and δ¹⁵N values of sediments were (-24.2 ± 1.2) per thousand and (4.1 ± 0.7) per thousand. The results of correlation analysis indicated that there were positively significantly correlated relationships between the stable isotopes values of large particle organic matters with those of small particle organic matters (P stable isotopes values of particle organic matters with those of sediments (P < 0.05). The δ¹⁵N values of particle organic matters in water surface were higher than those in deep layer. The results of correlation analysis indicated that the δ¹⁵N values of large particle organic matters were positive significantly correlated with the concentration of TN (P < 0.05), and the δ¹⁵N values of particle organic matters were positively significantly

  14. Nonlinear Wave-Particle Interaction: Implications for Newborn Planetary and Backstreaming Proton Velocity Distribution Functions

    Science.gov (United States)

    Romanelli, N.; Mazelle, C.; Meziane, K.

    2018-02-01

    Seen from the solar wind (SW) reference frame, the presence of newborn planetary protons upstream from the Martian and Venusian bow shocks and SW protons reflected from each of them constitutes two sources of nonthermal proton populations. In both cases, the resulting proton velocity distribution function is highly unstable and capable of giving rise to ultralow frequency quasi-monochromatic electromagnetic plasma waves. When these instabilities take place, the resulting nonlinear waves are convected by the SW and interact with nonthermal protons located downstream from the wave generation region (upstream from the bow shock), playing a predominant role in their dynamics. To improve our understanding of these phenomena, we study the interaction between a charged particle and a large-amplitude monochromatic circularly polarized electromagnetic wave propagating parallel to a background magnetic field, from first principles. We determine the number of fix points in velocity space, their stability, and their dependence on different wave-particle parameters. Particularly, we determine the temporal evolution of a charged particle in the pitch angle-gyrophase velocity plane under nominal conditions expected for backstreaming protons in planetary foreshocks and for newborn planetary protons in the upstream regions of Venus and Mars. In addition, the inclusion of wave ellipticity effects provides an explanation for pitch angle distributions of suprathermal protons observed at the Earth's foreshock, reported in previous studies. These analyses constitute a mean to evaluate if nonthermal proton velocity distribution functions observed at these plasma environments present signatures that can be understood in terms of nonlinear wave-particle processes.

  15. Incidence and distribution of coeliac disease in Campania (Italy): 2011-2013.

    Science.gov (United States)

    Zingone, Fabiana; West, Joe; Auricchio, Renata; Maria Bevilacqua, Rosa; Bile, Guido; Borgheresi, Patrizia; Erminia Bottiglieri, Maria; Caldore, Mariano; Capece, Giuseppe; Cristina Caria, Maria; Crudele, Antonio; Cuomo, Rosario; Lucia Garofano, Maria; Giardullo, Nicola; Gerarda Gravina, Antonietta; Greco, Luigi; Iannotta, Patrizia; Kosova, Paolo; Lamanda, Roberto; Malamisura, Basilio; Marmo, Riccardo; Napoli, Gianfranco; Nardone, Gerardo; Pacelli, Maria; Pascarella, Filomena; Riccio, Elisabetta; Riegler, Gabriele; Rispo, Antonio; Rocco, Alba; Romano, Marco; Saffiotti, Ottavio; Saviano, Paola; Sorrentini, Italo; Speranza, Pietro; Tolone, Carlo; Tortora, Raffaella; Troncone, Riccardo; Ciacci, Carolina

    2015-04-01

    There exists a wide variation in the reported incidence of coeliac disease in recent decades. We aimed to evaluate the incidence rate of coeliac diagnoses performed in an Italian region, Campania, between 2011 and 2013 and its variation therein. All coeliac diagnoses made from 2011 to 2013 and registered within the Campania coeliac disease register (CeliacDB) were identified. Incidence rates were analysed by sex, age and province of residence, with a Poisson model fitted to determine incidence rate ratios. We found 2049 coeliac disease diagnoses registered in the CeliacDB between 2011 and 2013; 1441 of these patients were female (70.4%) and 1059 were aged less than 19 years (51.7%). The overall incidence of coeliac disease in Campania was 11.8 per 100,000 person-years (95% CI 11.3-12.3) during the study period, with marked variation by age [27.4 per 100,000 person-years (95% CI 25.8-29.1) in children under 19 years of age and 7.3 per 100,000 (95% CI 6.8-7.8) in adults] and sex [16.1 per 100,000 person-years in females (95% CI 15.3-16.9) and 7.2 per 100,000 person-years in males (95% CI 6.6-7.8)]. Coeliac disease incidence was roughly similar in Naples, Salerno, Caserta and Avellino, but about half in Benevento. More than 80% of our study population was diagnosed by the combination of positive antitransglutaminase IgA and Marsh 3. More than half of the patients were symptomatic at the time of coeliac disease diagnosis (39.7% had a classical presentation and 21.1% a non-classical one according to the Oslo definition). Coeliac disease incidence was roughly similar among Campania provinces, except in Benevento where it was about half, probably due to less awareness of coeliac disease in this area. The incidence of coeliac disease in Campania appears to be lower than that reported by most of the previous literature, suggesting the necessity of new coeliac awareness programmes.

  16. Size distribution of particle-phase molecular markers during a severe winter pollution episode.

    Science.gov (United States)

    Kleeman, Michael J; Riddle, Sarah G; Jakober, Chris A

    2008-09-01

    Airborne particulate matter was collected using filter samplers and cascade impactors in six size fractions below 1.8 microm during a severe winter air pollution event at three sites in the Central Valley of California. The smallest size fraction analyzed was 0.056 0.8) for retene, benzo[ghi]flouranthene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, perylene, indeno[1,2,3-cd]pyrene, benzo[ghi]perylene, coronene, MW302 polycyclic aromatic hydrocarbon (PAHs), 17beta(H)-21alpha(H)-30-norhopane, 17alpha(H)-21beta(H)-hopane, alphabetabeta-20R-C29-ethylcholestane, levoglucosan, and cholesterol. Of these compounds, levoglucosan was present in the highest concentration (60-2080 ng m(-3)) followed by cholesterol (6-35 ng m(-3)), PAHs (2-38 ng m(-3)), and hopanes and steranes (0-2 ng m(-3)). Nighttime concentrations were higher than daytime concentrations in all cases. Organic compound size distributions were generally similar to the total carbon size distributions during the nighttime but showed greater variability during the daytime. This may reflect the dominance of fresh emission in the stagnant surface layer during the evening hours and the presence of aged organic aerosol at the surface during the daytime when the atmosphere is better mixed. All of the measured organic compound particle size distributions had a single mode that peaked somewhere between 0.18 and 0.56 microm, but the width of each distribution varied by compound. Cholesterol generally had the broadest particle size distribution, while benzo[ghi]perylene and 17alpha(H)-21beta(H)-29-norhopane generally had sharper peaks. The difference between the size distributions of the various particle-phase organic compounds reflects the fact that these compounds exist in particles emitted from different sources. The results of the current study will prove useful for size-resolved source apportionment exercises.

  17. Alpha spectrometric characterization of process-related particle size distributions from active particle sampling at the Los Alamos National Laboratory uranium foundry

    Energy Technology Data Exchange (ETDEWEB)

    Plionis, Alexander A [Los Alamos National Laboratory; Peterson, Dominic S [Los Alamos National Laboratory; Tandon, Lav [Los Alamos National Laboratory; Lamont, Stephen P [Los Alamos National Laboratory

    2009-01-01

    Uranium particles within the respirable size range pose a significant hazard to the health and safety of workers. Significant differences in the deposition and incorporation patterns of aerosols within the respirable range can be identified and integrated into sophisticated health physics models. Data characterizing the uranium particle size distribution resulting from specific foundry-related processes are needed. Using personal air sampling cascade impactors, particles collected from several foundry processes were sorted by activity median aerodynamic diameter onto various Marple substrates. After an initial gravimetric assessment of each impactor stage, the substrates were analyzed by alpha spectrometry to determine the uranium content of each stage. Alpha spectrometry provides rapid nondestructive isotopic data that can distinguish process uranium from natural sources and the degree of uranium contribution to the total accumulated particle load. In addition, the particle size bins utilized by the impactors provide adequate resolution to determine if a process particle size distribution is: lognormal, bimodal, or trimodal. Data on process uranium particle size values and distributions facilitate the development of more sophisticated and accurate models for internal dosimetry, resulting in an improved understanding of foundry worker health and safety.

  18. A visual basic program to generate sediment grain-size statistics and to extrapolate particle distributions

    Science.gov (United States)

    Poppe, L.J.; Eliason, A.H.; Hastings, M.E.

    2004-01-01

    Measures that describe and summarize sediment grain-size distributions are important to geologists because of the large amount of information contained in textural data sets. Statistical methods are usually employed to simplify the necessary comparisons among samples and quantify the observed differences. The two statistical methods most commonly used by sedimentologists to describe particle distributions are mathematical moments (Krumbein and Pettijohn, 1938) and inclusive graphics (Folk, 1974). The choice of which of these statistical measures to use is typically governed by the amount of data available (Royse, 1970). If the entire distribution is known, the method of moments may be used; if the next to last accumulated percent is greater than 95, inclusive graphics statistics can be generated. Unfortunately, earlier programs designed to describe sediment grain-size distributions statistically do not run in a Windows environment, do not allow extrapolation of the distribution's tails, or do not generate both moment and graphic statistics (Kane and Hubert, 1963; Collias et al., 1963; Schlee and Webster, 1967; Poppe et al., 2000)1.Owing to analytical limitations, electro-resistance multichannel particle-size analyzers, such as Coulter Counters, commonly truncate the tails of the fine-fraction part of grain-size distributions. These devices do not detect fine clay in the 0.6–0.1 μm range (part of the 11-phi and all of the 12-phi and 13-phi fractions). Although size analyses performed down to 0.6 μm microns are adequate for most freshwater and near shore marine sediments, samples from many deeper water marine environments (e.g. rise and abyssal plain) may contain significant material in the fine clay fraction, and these analyses benefit from extrapolation.The program (GSSTAT) described herein generates statistics to characterize sediment grain-size distributions and can extrapolate the fine-grained end of the particle distribution. It is written in Microsoft

  19. Plastic Bonded Explosive (PBX) Particle Size Distribution (PSD) Measurements Using an Image Analysis System

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Gregg K. [Univ. of Wyoming, Laramie, WY (United States)

    2003-06-01

    The slurry process for producing plastic bonded explosives (PBX) has been used for many years. However, until recently the mechanisms involved have not been studied quantitatively to determine the effects of the various control variables. Recently, the effects of operating variables on the final product have been studied; however, no attempt was made to measure particle growth during the slurry process. This study applies an image analysis tool to measure particle size distributions (PSDs) during the slurry process to produce PBX 9501, a specific formulation used in nuclear weapons. The observed PBX 9501 slurry behavior leads away from the typical population balance description of agglomeration, that is, a discrete particle-particle coalescence mechanism. The behavior observed in these experiments indicates that the initial state of the system contains a number of smaller particles clustered together. The cluster then coalesces into a large particle as solvent is removed and the slurry continuously mixed. Other small fragments are picked up and a relatively small amount of growth is observed. A mass transfer model adequately describes solvent removal, and an empirical model is developed to describe the growth behavior in terms of measured process variables. The image system is applied to dried molding powders. The PSD measurement results of the PBX 9501 library lots, historic samples set aside as PBX 9501 lots were accepted from the manufacturer, are also discussed and analyzed. A correlation analysis was conducted to find relationships between the measured PSD and other properties such as bulk density and pressed densities. While no significant correlation was found between the measured PSD and averaged bulk densities for the library lots, significant correlations are found between the measured PSD and pressed density. The final part of the study was to scale-up the PSD measurement capability. Since the large-scale processes are not yet operational, this work

  20. Suspended liquid particle disturbance on laser-induced blast wave and low density distribution

    Science.gov (United States)

    Ukai, Takahiro; Zare-Behtash, Hossein; Kontis, Konstantinos

    2017-12-01

    The impurity effect of suspended liquid particles on the laser-induced gas breakdown was experimentally investigated in quiescent gas. The focus of this study is the investigation of the influence of the impurities on the shock wave structure as well as the low density distribution. A 532 nm Nd:YAG laser beam with an 188 mJ/pulse was focused on the chamber filled with suspended liquid particles 0.9 ± 0.63 μm in diameter. Several shock waves are generated by multiple gas breakdowns along the beam path in the breakdown with particles. Four types of shock wave structures can be observed: (1) the dual blast waves with a similar shock radius, (2) the dual blast waves with a large shock radius at the lower breakdown, (3) the dual blast waves with a large shock radius at the upper breakdown, and (4) the triple blast waves. The independent blast waves interact with each other and enhance the shock strength behind the shock front in the lateral direction. The triple blast waves lead to the strongest shock wave in all cases. The shock wave front that propagates toward the opposite laser focal spot impinges on one another, and thereafter a transmitted shock wave (TSW) appears. The TSW interacts with the low density core called a kernel; the kernel then longitudinally expands quickly due to a Richtmyer-Meshkov-like instability. The laser-particle interaction causes an increase in the kernel volume which is approximately five times as large as that in the gas breakdown without particles. In addition, the laser-particle interaction can improve the laser energy efficiency.

  1. Heap Leaching of Caliche Ore. Modeling of a Multicomponent System with Particle Size Distribution

    Directory of Open Access Journals (Sweden)

    Javier I. Ordóñez

    2017-09-01

    Full Text Available Caliche is a mineral exploited in northern Chile, from which iodine and Nitrate salts (saltpeter are obtained. This ore is the most important source of iodine in the world and is processed mainly by heap leaching using water as a leaching agent. Heap leaching of caliche ore is carried out by the stacking of ROM (Run-Of-Mine material, where the particle size distribution covers a wide range, from a few millimeters up to several decimeters, even diameters about 1 m. During the leaching, the multiple soluble species of caliche, which can reach total fractions larger than 40%, are dissolved at different rates, mainly controlled by their solubilities. When it occurs and unlike most other leachable ores, the particle size diminishes. The leaching modeling of several soluble species of caliche has been recently addressed; however, one of the main assumptions is the idealization that the heap is composed of particles of the same size. The present work aims to complement the previously formulated phenomenological models for caliche ore leaching, through a model that considers the simultaneous dissolution of two species from caliche with three different particle sizes. These two water-soluble species have different solubilities and dissolution rates and the conceptual model considers that both species are dissolved at the particle surface. When the most soluble species is being depleted, the particle collapses, leaving a remaining fraction of the less soluble species together with insoluble material. The less soluble species is now being dissolved from the collapsed material. This article also includes the experimental verification of the conceptual model using data obtained from column leaching tests conducted for this purpose, focusing on the dissolution of two soluble species: Nitrate and Magnesium.

  2. Effects of target size on the comparison of photon and charged particle dose distributions

    International Nuclear Information System (INIS)

    Phillips, M.H.; Frankel, K.A.; Tjoa, T.; Lyman, J.T.; Fabrikant, J.I.; Levy, R.P.

    1989-12-01

    The work presented here is part of an ongoing project to quantify and evaluate the differences in the use of different radiation types and irradiation geometries in radiosurgery. We are examining dose distributions for photons using the ''Gamma Knife'' and the linear accelerator arc methods, as well as different species of charged particles from protons to neon ions. A number of different factors need to be studied to accurately compare the different modalities such as target size, shape and location, the irradiation geometry, and biological response. This presentation focuses on target size, which has a large effect on the dose distributions in normal tissue surrounding the lesion. This work concentrates on dose distributions found in radiosurgery, as opposed to those usually found in radiotherapy. 5 refs., 2 figs

  3. Effect of a generalized particle momentum distribution on plasma nuclear fusion rates

    International Nuclear Information System (INIS)

    Kim, Yeong E.; Zubarev, Alexander L.

    2006-01-01

    We investigate the effect of a generalized particle momentum distribution derived by Galitskii and Yakimets (GY) on nuclear reaction rates in plasma. We derive an approximate semi-analytical formula for nuclear fusion reaction rate between nuclei in a plasma (quantum plasma nuclear fusion; or QPNF). The QPNF formula is applied to calculate deuteron-deuteron fusion rate in a plasma, and the results are compared with the results calculated with the conventional Maxwell-Boltzmann velocity distribution. As an application, we investigate the deuteron-deuteron fusion rate for mobile deuterons in a deuterated metal/alloy. The calculated deuteron-deuteron fusion rates at low energies are enormously enhanced due to the modified tail of the GY's generalized momentum distribution. Our preliminary estimates indicate also that the deuteron-lithium (D+Li) fusion rate and the proton-lithium (p+Li) fusion rate in a metal/alloy at ambient temperatures are also substantially enhanced. (author)

  4. Particle size distribution of iron nanomaterials in biological medium by SR-SAXS method

    International Nuclear Information System (INIS)

    Jing Long; Feng Weiyue; Wang Bing; Wang Meng; Ouyang Hong; Zhao Yuliang; Chai Zhifang; Wang Yun; Wang Huajiang; Zhu Motao; Wu Zhonghua

    2009-01-01

    A better understanding of biological effects of nanomaterials in organisms requests knowledge of the physicochemical properties of nanomaterials in biological systems. Affected by high concentration salts and proteins in biological medium, nanoparticles are much easy to agglomerate,hence the difficulties in characterizing size distribution of the nanomaterials in biological medium.In this work, synchrotron radiation small angle X-ray scattering(SR-SAXS) was used to determine size distributions of Fe, Fe 2 O 3 and Fe 3 O 4 nanoparticles of various concentrations in PBS and DMEM culture medium. The results show that size distributions of the nanomaterials could perfectly analyzed by SR-SAXS. The SR-SAXS data were not affected by the particle content and types of the dispersion medium.It is concluded that SR-SAXS can be used for size measurement of nanomaterials in unstable dispersion systems. (authors)

  5. Displaced Path Integral Formulation for the Momentum Distribution of Quantum Particles

    Science.gov (United States)

    Lin, Lin; Morrone, Joseph A.; Car, Roberto; Parrinello, Michele

    2010-09-01

    The proton momentum distribution, accessible by deep inelastic neutron scattering, is a very sensitive probe of the potential of mean force experienced by the protons in hydrogen-bonded systems. In this work we introduce a novel estimator for the end-to-end distribution of the Feynman paths, i.e., the Fourier transform of the momentum distribution. In this formulation, free particle and environmental contributions factorize. Moreover, the environmental contribution has a natural analogy to a free energy surface in statistical mechanics, facilitating the interpretation of experiments. The new formulation is not only conceptually but also computationally advantageous. We illustrate the method with applications to an empirical water model, ab initio ice, and one dimensional model systems.

  6. Distribution and histologic effects of intravenously administered amorphous nanosilica particles in the testes of mice

    International Nuclear Information System (INIS)

    Morishita, Yuki; Yoshioka, Yasuo; Satoh, Hiroyoshi; Nojiri, Nao; Nagano, Kazuya; Abe, Yasuhiro; Kamada, Haruhiko; Tsunoda, Shin-ichi; Nabeshi, Hiromi; Yoshikawa, Tomoaki; Tsutsumi, Yasuo

    2012-01-01

    Highlights: ► There is rising concern regarding the potential health risks of nanomaterials. ► Few studies have investigated the effect of nanomaterials on the reproductive system. ► Here, we evaluated the intra-testicular distribution of nanosilica particles. ► We showed that nanosilica particles can penetrate the blood-testis barrier. ► These data provide basic information on ways to create safer nanomaterials. -- Abstract: Amorphous nanosilica particles (nSP) are being utilized in an increasing number of applications such as medicine, cosmetics, and foods. The reduction of the particle size to the nanoscale not only provides benefits to diverse scientific fields but also poses potential risks. Several reports have described the in vivo and in vitro toxicity of nSP, but few studies have examined their effects on the male reproductive system. The aim of this study was to evaluate the testicular distribution and histologic effects of systemically administered nSP. Mice were injected intravenously with nSP with diameters of 70 nm (nSP70) or conventional microsilica particles with diameters of 300 nm (nSP300) on two consecutive days. The intratesticular distribution of these particles 24 h after the second injection was analyzed by transmission electron microscopy. nSP70 were detected within sertoli cells and spermatocytes, including in the nuclei of spermatocytes. No nSP300 were observed in the testis. Next, mice were injected intravenously with 0.4 or 0.8 mg nSP70 every other day for a total of four administrations. Testes were harvested 48 h and 1 week after the last injection and stained with hematoxylin–eosin for histologic analysis. Histologic findings in the testes of nSP70-treated mice did not differ from those of control mice. Taken together, our results suggest that nSP70 can penetrate the blood-testis barrier and the nuclear membranes of spermatocytes without producing apparent testicular injury.

  7. Road versus roadside particle size distribution in a hot Mediterranean summer--estimation of fleet emission factors.

    Science.gov (United States)

    Baalbaki, Rima; Al-Assaad, Kassem; Mehanna, Carl-Joe; Saliba, Najat A; Katurji, Marwan; Roumié, Mohamad

    2013-03-01

    Particle size distribution at major on-road, roadside, and university-ground sites in Lebanon were studied in summer 2011. In a predominant old traffic fleet, it is shown that calculated PM2.5 mass emission factors (EFs) conform to those of heavy duty vehicles. When compared to roads in California, higher PM2.5 mass but similar particle number EFs are obtained for the average fleet of the on-road sites. This confirms the observed particle size distribution pattern, rich in particles in the accumulation range mainly between 0.425 and 0.675 microm with a prevalent peak at 0.475 microm. Corresponding total particle counts (TC) measured on the roadside are as high as 14,050 particles/cm3 and are up to 67% higher than particle counts measured at the university-ground site. In a hot, dry and humid summer weather with consistent temperature oscillations, particle dispersion is shown to be a function of meteorological factors, mainly the effect of the boundary-layer thickness, with particle counts measured during the morning being around 40% higher than particle counts measured during the afternoon. In a hot and humid Mediterranean summer, high emission factors are associated with an old car fleet. The observed diurnal variation in the particle count is attributed to the change in the thickness boundary layer in summer. In comparison to road sites, the particle size distribution shows the prevalence of larger size particles. Particle counts measured at the roadside sites are at least 20% higher than those of the road sites. The findings call for the reinforcement of local regulations on car age. Furthermore, the high number of particles can cause or aggravate a number of health and ecosystem problems.

  8. Spatial distribution and occurrence probability of regional new particle formation events in eastern China

    Science.gov (United States)

    Shen, Xiaojing; Sun, Junying; Kivekäs, Niku; Kristensson, Adam; Zhang, Xiaoye; Zhang, Yangmei; Zhang, Lu; Fan, Ruxia; Qi, Xuefei; Ma, Qianli; Zhou, Huaigang

    2018-01-01

    In this work, the spatial extent of new particle formation (NPF) events and the relative probability of observing particles originating from different spatial origins around three rural sites in eastern China were investigated using the NanoMap method, using particle number size distribution (PNSD) data and air mass back trajectories. The length of the datasets used were 7, 1.5, and 3 years at rural sites Shangdianzi (SDZ) in the North China Plain (NCP), Mt. Tai (TS) in central eastern China, and Lin'an (LAN) in the Yangtze River Delta region in eastern China, respectively. Regional NPF events were observed to occur with the horizontal extent larger than 500 km at SDZ and TS, favoured by the fast transport of northwesterly air masses. At LAN, however, the spatial footprint of NPF events was mostly observed around the site within 100-200 km. Difference in the horizontal spatial distribution of new particle source areas at different sites was connected to typical meteorological conditions at the sites. Consecutive large-scale regional NPF events were observed at SDZ and TS simultaneously and were associated with a high surface pressure system dominating over this area. Simultaneous NPF events at SDZ and LAN were seldom observed. At SDZ the polluted air masses arriving over the NCP were associated with higher particle growth rate (GR) and new particle formation rate (J) than air masses from Inner Mongolia (IM). At TS the same phenomenon was observed for J, but GR was somewhat lower in air masses arriving over the NCP compared to those arriving from IM. The capability of NanoMap to capture the NPF occurrence probability depends on the length of the dataset of PNSD measurement but also on topography around the measurement site and typical air mass advection speed during NPF events. Thus the long-term measurements of PNSD in the planetary boundary layer are necessary in the further study of spatial extent and the probability of NPF events. The spatial extent, relative

  9. Spatial distribution and occurrence probability of regional new particle formation events in eastern China

    Directory of Open Access Journals (Sweden)

    X. Shen

    2018-01-01

    Full Text Available In this work, the spatial extent of new particle formation (NPF events and the relative probability of observing particles originating from different spatial origins around three rural sites in eastern China were investigated using the NanoMap method, using particle number size distribution (PNSD data and air mass back trajectories. The length of the datasets used were 7, 1.5, and 3 years at rural sites Shangdianzi (SDZ in the North China Plain (NCP, Mt. Tai (TS in central eastern China, and Lin'an (LAN in the Yangtze River Delta region in eastern China, respectively. Regional NPF events were observed to occur with the horizontal extent larger than 500 km at SDZ and TS, favoured by the fast transport of northwesterly air masses. At LAN, however, the spatial footprint of NPF events was mostly observed around the site within 100–200 km. Difference in the horizontal spatial distribution of new particle source areas at different sites was connected to typical meteorological conditions at the sites. Consecutive large-scale regional NPF events were observed at SDZ and TS simultaneously and were associated with a high surface pressure system dominating over this area. Simultaneous NPF events at SDZ and LAN were seldom observed. At SDZ the polluted air masses arriving over the NCP were associated with higher particle growth rate (GR and new particle formation rate (J than air masses from Inner Mongolia (IM. At TS the same phenomenon was observed for J, but GR was somewhat lower in air masses arriving over the NCP compared to those arriving from IM. The capability of NanoMap to capture the NPF occurrence probability depends on the length of the dataset of PNSD measurement but also on topography around the measurement site and typical air mass advection speed during NPF events. Thus the long-term measurements of PNSD in the planetary boundary layer are necessary in the further study of spatial extent and the probability of NPF events. The spatial

  10. Measurement of charged-particle multiplicity distributions and their $H_q$ moments in hadronic Z decays at LEP

    CERN Document Server

    Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Buijs, A.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; van Dalen, J.A.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; van Dierendonck, D.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duinker, P.; Echenard, B.; Eline, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Ewers, A.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Hu, Y.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, Jasper; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Krenz, W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Lubelsmeyer, K.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mangeol, D.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Niessen, T.; Nisati, A.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Palomares, C.; Pandoulas, D.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofev, D.O.; Prokofiev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Roux, B.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Sanders, M.P.; Schafer, C.; Schegelsky, V.; Schmidt-Kaerst, S.; Schmitz, D.; Schopper, H.; Schotanus, D.J.; Schwering, G.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Siedenburg, T.; Son, D.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Veszpremi, V.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobyov, A.A.; Wadhwa, M.; Wallraff, W.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wienemann, P.; Wilkens, H.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zilizi, G.; Zimmermann, B.; Zoller, M.

    2003-01-01

    The charged-particle multiplicity distribution and the inclusive momentum distribution, in terms of the variable $\\xi$, are measured for all hadronic events as well as for light-quark and b-quark events in $\\mathrm{e}^{+}\\mathrm{e}^{-}$ collisions at the Z pole. Moments of the charged-particle multiplicity distributions are calculated, and the peak positions of the $\\xi$ distributions determined. The multiplicity distributions are studied in terms of their $H_q$ moments. Their quasi-oscillations when plotted versus the rank of the moment are compared with different theoretical approaches.

  11. [Municipal distribution of the incidence of the most common tumours in an area with high cancer mortality].

    Science.gov (United States)

    Viñas Casasola, Manuel Jesús; Fernández Navarro, Pablo; Fajardo Rivas, María Luisa; Gurucelain Raposo, José Luis; Alguacil Ojeda, Juan

    To describe the geographic distribution patterns of the municipal incidence of the most common tumours in the Huelva province (Spain) as compared to the estimated incidence for all of Spain. Relative risk (RR) was computed based on the conditional autoregressive model proposed by Besag, York and Mollié by applying the INLA tool to the cancer data for 2007-2011 for the following tumour locations: colon, rectum and anus (men and women); trachea, bronchia, and lungs, prostate and bladder in men; and breasts in women. The RR was presented in in choropleth and isopleth (with kriging interpolation) risk maps. RR for bladder cancer in men was greater than 1.0 in all municipalities, with confidence intervals over 1.0 in four municipalities; Madrid having a 1.56 RR (95%CI 1.30-1.67). For prostate cancer, a posteriori probabilities were below 0.1 in 68 of the 79 municipalities. For lung cancer, nine municipalities had confidence limits below 1.0, almost all of them in western Spain. For women, the RR for breast cancer was significantly higher in the capital of province area. The cancer incidence rates for the Huelva province were, in general, similar to those estimated for Spain, standing out bladder cancer in men (35% higher) and prostate cancer (30% lower). In the Huelva province, there is a geographical municipal distribution of cancer incidence with well-defined patterns for some specific tumour locations, with overall incidence rates very similar to those in the rest of Spain. Copyright © 2016 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. A Neural Network Approach for Identifying Particle Pitch Angle Distributions in Van Allen Probes Data

    Science.gov (United States)

    Souza, V. M.; Vieira, L. E. A.; Medeiros, C.; Da Silva, L. A.; Alves, L. R.; Koga, D.; Sibeck, D. G.; Walsh, B. M.; Kanekal, S. G.; Jauer, P. R.; hide

    2016-01-01

    Analysis of particle pitch angle distributions (PADs) has been used as a means to comprehend a multitude of different physical mechanisms that lead to flux variations in the Van Allen belts and also to particle precipitation into the upper atmosphere. In this work we developed a neural network-based data clustering methodology that automatically identifies distinct PAD types in an unsupervised way using particle flux data. One can promptly identify and locate three well-known PAD types in both time and radial distance, namely, 90deg peaked, butterfly, and flattop distributions. In order to illustrate the applicability of our methodology, we used relativistic electron flux data from the whole month of November 2014, acquired from the Relativistic Electron-Proton Telescope instrument on board the Van Allen Probes, but it is emphasized that our approach can also be used with multiplatform spacecraft data. Our PAD classification results are in reasonably good agreement with those obtained by standard statistical fitting algorithms. The proposed methodology has a potential use for Van Allen belt's monitoring.

  13. Particle size distribution and behavior of sulfate aerosols in a coastal region

    Energy Technology Data Exchange (ETDEWEB)

    Fujimura, M.; Hashimoto, Y.

    1979-01-01

    To obtain fundamental knowledge about sulfate aerosols, a field research was conducted in a coastal region distant from industrial pollution sources. The aerosol samples were analyzed for some elements, sulfate and ammonium ions. Sulfate was determined by the turbidimetry with 2-aminoperimidine, and ammonium was by the colorimetry of indophenol method. Trace elements with short-lived nuclides were analyzed by instrumental neutron activation analysis. The mass-size distribution curve of total aerosols was the general bimodal pattern, although the concentration level was very low. Most of sulfate and ammonium salts were distributed in the fine particle range less than 2 microns in aerodynamic diameter, but sulfate had another peak, thought to be of maritime origin, in the coarse particle range. Nevertheless, many fine sulfate particles that had been produced secondarily in the atmosphere were found in such a less polluted coastal region. The change of the sulfate concentrations obtained by the two-stage Andersen type sampler showed a correlation with the humidity. This may suggest that the formation of sulfate aerosols from sulfur dioxide could be related to a catalytic oxidation process in water drops.

  14. Fluids and their Effect on Measurements on Lunar Soil Particle size Distribution

    Science.gov (United States)

    Cooper, B. L.; McKay, D. S.; Wallace, W. T.; Gonzalex, C. P.

    2011-01-01

    From the late 1960s until now, lunar soil particle size distributions have typically been determined by sieving sometimes dry, and at other times with fluids such as water or Freon. Laser diffraction instruments allow rapid assessment of particle size distribution, and eventually may replace sieve measurements. However, when measuring lunar soils with laser diffraction instruments, care must be taken in choosing a carrier fluid that is compatible with lunar material. Distilled water is the fluid of choice for laser diffraction measurements of substances when there is no concern about adverse effects of water on the material being measured. When we began our analyses of lunar soils using laser diffraction, our first measurements were made with distilled water. Although the medians that we measured were comparable to earlier sieve data, the means tended to be significantly larger than expected. The effect of water vapor on lunar soil has been studied extensively. The particles interact strongly with water vapor, and subsequent adsorptions of nitrogen showed that the specific surface area increased as much as threefold after exposure to moisture. It was observed that significant porosity had been generated by this exposure to water vapor. The possibility of other physical changes in the surfaces of the grains was not studied.

  15. Inclusive charged particle distributions in deep inelastic scattering events at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-11-01

    A measurement of inclusive charged particle distributions in deep inelastic ep scattering for γ * p centre-of-mass energies 75 2 2 from the ZEUS detector at HERA is presented. The differential charged particle rates in the γ*p centre-of-mass system as a function of the scaled longitudinal momentum, x F , and of the transverse momentum, p* t and t 2 >, as a function of x F , W and Q 2 are given. Separate distributions are shown for events with (LRG) and without (NRG) a rapidity gap with respect to the proton direction. The data are compared with results from experiments at lower beam energies, with the naive quark parton model and with parton models including perturbative QCD corrections. The comparison shows the importance of the higher order QCD processes. Significant differences of the inclusive charged particle rates between NRG and LRG events at the same W are observed. The value of t 2 > for LRG events with a hadronic mass M X , which excludes the forward produced baryonic system, is similar to the t 2 > value observed in fixed target experiments at W∼M X . (orig.)

  16. Charge-to-Mass Dependence of the Longitudinal Distribution of Solar Energetic Particles

    Science.gov (United States)

    Cohen, C. M.; Mason, G. M.; Mewaldt, R. A.

    2015-12-01

    Studies combining observations from near-Earth spacecraft and the twin STEREO spacecraft have resulted in a number of surprising results regarding the spread of solar energetic particles (SEPs) in longitude. The 7 February 2010 3He-rich event was observed by spacecraft spread over 136 degrees, extending far beyond the expected longitudinal extent of such events whose origins are compact flaring regions on the Sun. Intensities of 25 MeV protons from the 3 November 2011 SEP event increased abruptly at all three spacecraft with onsets occurring within 30 minutes of each other even though the spacecraft were roughly equally distributed in longitude around the Sun. These types of observations challenge our understanding of the transport of SEPs. As many transport mechanisms are governed by a particle's rigidity, it is useful to examine the SEP longitude distribution as a function of particles' charge-to-mass ratios. We present the results of such a study using more than 30 large SEP events observed by two or three spacecraft in solar cycle 24.

  17. Quantitative image analysis for evaluating the coating thickness and pore distribution in coated small particles.

    Science.gov (United States)

    Laksmana, F L; Van Vliet, L J; Hartman Kok, P J A; Vromans, H; Frijlink, H W; Van der Voort Maarschalk, K

    2009-04-01

    This study aims to develop a characterization method for coating structure based on image analysis, which is particularly promising for the rational design of coated particles in the pharmaceutical industry. The method applies the MATLAB image processing toolbox to images of coated particles taken with Confocal Laser Scanning Microscopy (CSLM). The coating thicknesses have been determined along the particle perimeter, from which a statistical analysis could be performed to obtain relevant thickness properties, e.g. the minimum coating thickness and the span of the thickness distribution. The characterization of the pore structure involved a proper segmentation of pores from the coating and a granulometry operation. The presented method facilitates the quantification of porosity, thickness and pore size distribution of a coating. These parameters are considered the important coating properties, which are critical to coating functionality. Additionally, the effect of the coating process variations on coating quality can straight-forwardly be assessed. Enabling a good characterization of the coating qualities, the presented method can be used as a fast and effective tool to predict coating functionality. This approach also enables the influence of different process conditions on coating properties to be effectively monitored, which latterly leads to process tailoring.

  18. A differentiation method for separating a mixture of suspended particle size distributions

    Directory of Open Access Journals (Sweden)

    H. Q. Wang

    1999-01-01

    Full Text Available A simple method is proposed to partition a mixture of two populations in suspended particle size data. The method, termed here 'the differentiation method' is based on the function of the lognormal distribution. Suspended material in marine or estuarine situations often consists of difficult-to-interpret complex populations. The treatment of particle size data by the method described enables the confirmation of the lognormal law and also the demonstration of the occurrence of a combination of a number of populations which may not be distinguished by the classical Gaussian transformation or automatic methods. A simple combination of graphical and numerical techniques permits the decomposition and the easy determination of the various statistical parameters (median diameter, mean diameter, etc.... The method is applied to interpret observed size distributions of suspended particulate matter in the Seine estuary. The method enables the determination of the relative sizes of the constituent sub-populations that comprise the total suspended matter. In the example used to illustrate the method, particles are shown to be resuspended as a function of different hydrodynamic parameter.

  19. Log-cubic method for generation of soil particle size distribution curve.

    Science.gov (United States)

    Shang, Songhao

    2013-01-01

    Particle size distribution (PSD) is a fundamental physical property of soils. Traditionally, the PSD curve was generated by hand from limited data of particle size analysis, which is subjective and may lead to significant uncertainty in the freehand PSD curve and graphically estimated cumulative particle percentages. To overcome these problems, a log-cubic method was proposed for the generation of PSD curve based on a monotone piecewise cubic interpolation method. The log-cubic method and commonly used log-linear and log-spline methods were evaluated by the leave-one-out cross-validation method for 394 soil samples extracted from UNSODA database. Mean error and root mean square error of the cross-validation show that the log-cubic method outperforms two other methods. What is more important, PSD curve generated by the log-cubic method meets essential requirements of a PSD curve, that is, passing through all measured data and being both smooth and monotone. The proposed log-cubic method provides an objective and reliable way to generate a PSD curve from limited soil particle analysis data. This method and the generated PSD curve can be used in the conversion of different soil texture schemes, assessment of grading pattern, and estimation of soil hydraulic parameters and erodibility factor.

  20. Snow-borne nanosized particles: Abundance, distribution, composition, and significance in ice nucleation processes

    Science.gov (United States)

    Rangel-Alvarado, Rodrigo Benjamin; Nazarenko, Yevgen; Ariya, Parisa A.

    2015-11-01

    Physicochemical processes of nucleation constitute a major uncertainty in understanding aerosol-cloud interactions. To improve the knowledge of the ice nucleation process, we characterized physical, chemical, and biological properties of fresh snow using a suite of state-of-the-art techniques based on mass spectrometry, electron microscopy, chromatography, and optical particle sizing. Samples were collected at two North American Arctic sites, as part of international campaigns (2006 and 2009), and in the city of Montreal, Canada, over the last decade. Particle size distribution analyses, in the range of 3 nm to 10 µm, showed that nanosized particles are the most numerous (38-71%) in fresh snow, with a significant portion (11 to 19%) less than 100 nm in size. Particles with diameters less than 200 nm consistently exhibited relatively high ice-nucleating properties (on average ranged from -19.6 ± 2.4 to -8.1 ± 2.6°C). Chemical analysis of the nanosized fraction suggests that they contain bioorganic materials, such as amino acids, as well as inorganic compounds with similar characteristics to mineral dust. The implication of nanoparticle ubiquity and abundance in diverse snow ecosystems are discussed in the context of their importance in understanding atmospheric nucleation processes.

  1. Particle size distribution and PAH concentrations of incense smoke in a combustion chamber

    International Nuclear Information System (INIS)

    Yang, C.-R.; Lin, T.-C.; Chang, F.-H.

    2007-01-01

    The particle size distribution and the concentrations of polycyclic aromatic hydrocarbons (PAHs) in incense smoke were studied using a custom-designed combustion chamber. Among the nine types of incense investigated, the particle and the total PAH emission factors varied significantly. The average mass median aerodynamic diameter (MMAD) of the smoke aerosol was 262 ± 49 nm, which positively correlated to particle emission factor (mg/stick, p < 0.05). Coagulation was a major mechanism that dictates the MMAD of the smoke. The total toxic equivalency (the sum of the benzo[a]pyrene equivalent concentration) of the solid-phase PAHs (S-PAHs) was over 40 times higher than that of the corresponding gas-phase PAHs, indicating that the S-PAHs in incense smoke may pose potential health risk. Experiments show that each lowered percentage of total carbon content in the raw incense helped decrease the particle emission factor by 2.6 mg/g-incense, and the reduction of S-PAH emission factor ranged from 8.7 to 26% when the carbon content was lowered from 45 to 40%. - Emission profiles of PAHs from the nine types of studied incense appeared to share a common pattern

  2. Diabetes mellitus in a population of 180,000 insured dogs: incidence, survival, and breed distribution.

    Science.gov (United States)

    Fall, Tove; Hamlin, Helene Hansson; Hedhammar, Ake; Kämpe, Olle; Egenvall, Agneta

    2007-01-01

    Canine diabetes mellitus (DM) is a common endocrinopathy with an unclear etiology. For a better understanding of the underlying mechanisms, there is a need for comprehensive epidemiologic studies. Earlier studies have shown that the risk of disease is higher in certain dog breeds. Incidence, age of onset, survival and sex proportion of DM vary by breed. Data from a cohort of 182,087 insured dogs aged 5-12 years accounting for 652,898 dog-years at risk were studied retrospectively. Incidence rates by sex, breed, and geography were calculated with exact denominators. Age-specific incidence and survival after 1st DM claim were computed with Cox's regression and Kaplan-Meier survival function. Multivariable survival analysis was performed for the outcome diagnosis of DM with age, sex, and geography tested as fixed effects, previous endocrine or pancreatic diseases tested as time-dependent covariates, and breed tested as a random effect. The mean age at 1st insurance claim for the 860 DM dogs (72% females) was 8.6 years. The incidence of DM was 13 cases per 10,000 dog-years at risk. Australian Terriers, Samoyeds, Swedish Elkhounds, and Swedish Lapphunds were found to have the highest incidence. The proportion of females with DM varied significantly among breeds. Swedish Elkhounds, Beagles, Norwegian Elkhounds, and Border Collies that developed DM were almost exclusively females. The multivariable model showed that breed, previous hyperadrenocorticism, and female sex were risk factors for developing DM. Median survival time was 57 days after 1st claim. Excluding the 223 dogs that died within 1 day, the median survival time was 2 years after 1st claim of DM. The significant breed-specific sex and age differences shown in this study indicate that genetic variation could make breeds more or less susceptible to different types of DM.

  3. Angular Distribution of Damping Coefficient of Ablated Particle in Pure He, Ne, and Ar Gases

    Directory of Open Access Journals (Sweden)

    Yinglong Wang

    2011-01-01

    Full Text Available To investigate the angular distribution of damping coefficient of ablated particle under various ambient gases, nanocrystalline silicon films are systemically deposited on a circular substrate by pulse laser ablation in pure He, Ne, and Ar gases, respectively. Scanning electron microscopy images and Raman and X-ray diffraction spectra indicate that the average size of Si nanoparticles decreases with the increase of the departure angle between the film and the plume, and Ne gas induces the smallest and most uniform Si nanoparticles in size among all the three gases. Further theoretical simulation demonstrates the bigger the departure angle, the smaller the damping coefficient of ablated particle, and the damping coefficient in Ne gas is largest for the same angle, implying the most effective energy transfer between Si and ambient atoms.

  4. Energy distribution of the particles obtained after irradiation of carbon nanotubes with carbon projectiles

    Energy Technology Data Exchange (ETDEWEB)

    Denton, Cristian D. [Departament de Física Aplicada, Universitat d’Alacant, Apartat 99, E-03690 Alacant (Spain); Moreno-Marín, Juan Carlos; Heredia-Avalos, Santiago [Departament de Física, Enginyeria de Sistemes i Teoria de la Senyal, Universitat d’Alacant, Apartat 99, E-03690 Alacant (Spain)

    2015-06-01

    The idea of using carbon nanotubes (CNTs) as masks against irradiation has recently emerged, because of the region of a given material covered by a CNT can be protected from the effects of irradiation, creating nanowires. In this case, it is interesting to know in detail the number of generated recoils and their energy. In order to obtain these data, we simulate the irradiation of CNTs with carbon ions using a molecular dynamics code. To describe the interaction between carbon ions we use the Brenner potential joined smoothly to the Universal ZBL potential at short distances. We have analyzed the energy distributions of the carbon atoms emerging from the CNT for single projectile irradiation with incident energies from 30 eV to 5 keV. Our results show that the number and the energy of the recoil carbon atoms emerging from the CNT increases with the projectile incident energy. In average, each projectile with incident energy of 1 keV produces ∼3.6 recoils, which have a mean energy of 150 eV, while projectiles with 5 keV produce ∼7 recoils with a mean energy of 400 eV.

  5. Particle size distributions of currently used pesticides in ambient air of an agricultural Mediterranean area

    Science.gov (United States)

    Coscollà, Clara; Muñoz, Amalia; Borrás, Esther; Vera, Teresa; Ródenas, Milagros; Yusà, Vicent

    2014-10-01

    This work presents first data on the particle size distribution of 16 pesticides currently used in Mediterranean agriculture in the atmosphere. Particulate matter air samples were collected using a cascade impactor distributed into four size fractions in a rural site of Valencia Region, during July to September in 2012 and from May to July in 2013. A total of 16 pesticides were detected, including six fungicides, seven insecticides and three herbicides. The total concentrations in the particulate phase (TSP: Total Suspended Particulate) ranged from 3.5 to 383.1 pg m-3. Most of the pesticides (such as carbendazim, tebuconazole, chlorpyrifos-ethyl and chlorpyrifos-methyl) were accumulated in the ultrafine-fine (<1 μm) and coarse (2.5-10 μm) particle size fractions. Others like omethoate, dimethoate and malathion were presented only in the ultrafine-fine size fraction (<1 μm). Finally, diuron, diphenylamine and terbuthylazine-desethyl-2-OH also show a bimodal distribution but mainly in the coarse size fractions.

  6. Statistical analysis of secondary particle distributions in relativistic nucleus-nucleus collisions

    Science.gov (United States)

    Mcguire, Stephen C.

    1987-01-01

    The use is described of several statistical techniques to characterize structure in the angular distributions of secondary particles from nucleus-nucleus collisions in the energy range 24 to 61 GeV/nucleon. The objective of this work was to determine whether there are correlations between emitted particle intensity and angle that may be used to support the existence of the quark gluon plasma. The techniques include chi-square null hypothesis tests, the method of discrete Fourier transform analysis, and fluctuation analysis. We have also used the method of composite unit vectors to test for azimuthal asymmetry in a data set of 63 JACEE-3 events. Each method is presented in a manner that provides the reader with some practical detail regarding its application. Of those events with relatively high statistics, Fe approaches 0 at 55 GeV/nucleon was found to possess an azimuthal distribution with a highly non-random structure. No evidence of non-statistical fluctuations was found in the pseudo-rapidity distributions of the events studied. It is seen that the most effective application of these methods relies upon the availability of many events or single events that possess very high multiplicities.

  7. Probability distributions of bed load particle velocities, accelerations, hop distances, and travel times informed by Jaynes's principle of maximum entropy

    Science.gov (United States)

    Furbish, David; Schmeeckle, Mark; Schumer, Rina; Fathel, Siobhan

    2016-01-01

    We describe the most likely forms of the probability distributions of bed load particle velocities, accelerations, hop distances, and travel times, in a manner that formally appeals to inferential statistics while honoring mechanical and kinematic constraints imposed by equilibrium transport conditions. The analysis is based on E. Jaynes's elaboration of the implications of the similarity between the Gibbs entropy in statistical mechanics and the Shannon entropy in information theory. By maximizing the information entropy of a distribution subject to known constraints on its moments, our choice of the form of the distribution is unbiased. The analysis suggests that particle velocities and travel times are exponentially distributed and that particle accelerations follow a Laplace distribution with zero mean. Particle hop distances, viewed alone, ought to be distributed exponentially. However, the covariance between hop distances and travel times precludes this result. Instead, the covariance structure suggests that hop distances follow a Weibull distribution. These distributions are consistent with high-resolution measurements obtained from high-speed imaging of bed load particle motions. The analysis brings us closer to choosing distributions based on our mechanical insight.

  8. Red cell distribution width in relation to incidence of stroke and carotid atherosclerosis: a population-based cohort study.

    Directory of Open Access Journals (Sweden)

    Martin Söderholm

    Full Text Available Increased red cell distribution width (RDW has been related to poor prognosis in patients with cardiovascular disease, and is a predictor of cardiovascular mortality in the general population. The purpose of the present study was to investigate if RDW is associated with increased incidence of stroke and its subtypes in individuals from the general population.Red cell distribution width was measured in 26,879 participants (16,561 women and 10,318 men aged 45-73 years without history of coronary events or stroke, from the population-based Malmö Diet and Cancer Study. Incidences of total stroke and stroke subtypes over a mean follow-up of 15.2 years were calculated in relation to sex-specific quartiles of RDW. The presence of carotid plaque and intima-media thickness, as assessed by ultrasound, was studied in relation to RDW in a randomly selected subcohort (n = 5,309.Incidences of total stroke (n = 1,869 and cerebral infarction (n = 1,544 were both increased in individuals with high RDW. Hazard ratios (HRs in the highest compared to the lowest quartile were 1.31 for total stroke (95% confidence interval [CI]: 1.11-1.54, p for trend = 0.004 and 1.32 for cerebral infarction (95% CI: 1.10-1.58, p for trend = 0.004 after adjustment for stroke risk factors and hematological parameters. The adjusted HR for intracerebral hemorrhage (n = 230 was 1.44 (95% CI: 0.90-2.30 and the HR for subarachnoid hemorrhage (n = 75 was 0.94 (95% CI: 0.43-2.07, in the highest compared to the lowest quartile of RDW. Red cell distribution width was positively associated with intima-media thickness of the common carotid artery (p for trend = 0.011.Red cell distribution width in the highest quartile was associated with increased incidence of total stroke and cerebral infarction. There was no significant association between RDW and incidence of intracerebral or subarachnoid hemorrhage.

  9. The impact of mass transfer limitations on size distributions of particle associated SVOCs in outdoor and indoor environments

    DEFF Research Database (Denmark)

    Liu, Cong; Zhang, Yinping; Weschler, Charles J.

    2014-01-01

    Semi-volatile organic compounds (SVOCs) partition between the gas phase and airborne particles. The size distribution of particle-associated SVOCs impacts their fate in outdoor and indoor environments, as well as human exposure to these compounds and subsequent health risks. Allen et al. (1996......) previously proposed that the rate of mass transfer can impact polycyclic aromatic hydrocarbon (PAH) partitioning among different sized particles, especially for time scales relevant to urban aerosols. The present study quantitatively builds on this idea, presenting a model that incorporates dynamic SVOC....../particle interaction and applying this model to typical outdoor and indoor scenarios. The model indicates that the impact of mass transfer limitations on the size distribution of a particle-associated SVOC can be evaluated by the ratio of the time to achieve gas-particle equilibrium relative to the residence time...

  10. Particle Size Distribution Controls the Threshold Between Net Sediment Erosion and Deposition in Suspended Load Dominated Flows

    Science.gov (United States)

    Dorrell, R. M.; Amy, L. A.; Peakall, J.; McCaffrey, W. D.

    2018-02-01

    The central problem of describing most environmental and industrial flows is predicting when material is entrained into, or deposited from, suspension. The threshold between erosional and depositional flow has previously been modeled in terms of the volumetric amount of material transported in suspension. Here a new model of the threshold is proposed, which incorporates (i) volumetric and particle size limits on a flow's ability to transport material in suspension, (ii) particle size distribution effects, and (iii) a new particle entrainment function, where erosion is defined in terms of the power used to lift mass from the bed. While current suspended load transport models commonly use a single characteristic particle size, the model developed herein demonstrates that particle size distribution is a critical control on the threshold between erosional and depositional flow. The new model offers an order of magnitude, or better, improvement in predicting the erosional-depositional threshold and significantly outperforms existing particle-laden flow models.

  11. Particle size-shape distributions: the general spheroid problem. I. Mathematical model.

    Science.gov (United States)

    Orive, L M

    1976-08-01

    The development of stereological methods for the study of dilute phases of particles, voids or organelles embedded in a matrix, from measurements made on plane or linear intercepts through the aggregate, has deserved a great deal of effort. With almost no exception, the problem of describing the particulate phase is reduced to that of identifying the statistical distribution--histogram in practice--of a relevant size parameter, with the previous assumption that the particles are modelled by geometrical objects of a constant shape (e.g. spheres). Therefore, particles exhibiting a random variation about a given type of shape as well as a random variation in size, escape previous analyses. Such is the case of unequiaxed particles modelled by triaxial ellipsoids of variable size and eccentricity parameters. It has been conjectured (Moran, 1972) that this problem is indetermined in its generally (i.e. the elliptical sections do not furnish a sufficient information which permits a complete description of the ellipsoids). A proof of this conjecture is given in the Appendix. When the ellipsoids are biaxial (spheroids) and of the same type (prolate or oblate), the problem is identifiable. Previous attempts to solve it assume statistical independence between size and shape. A complete, theoretical solution of the spheroids problem--with the independence condition relaxed--is presented. A number of exact relationships--some of them of a striking simplicity--linking particle properties (e.g. mean-mean caliper length, mean axial ratio, correlation coefficient between principal diameters, etc.) on the one hand, with the major and minor dimensions of the ellipses of section on the other, emerge, and natural, consistent estimators of the mentioned properties are made easily accessible for practical computation. Finally, the scope and limitations of the mathematical model are discussed.

  12. Cluster and single-particle distributions in nucleus-nucleus interactions

    International Nuclear Information System (INIS)

    Kulakov, B.A.; Karachuk, Yu.

    1997-01-01

    Relativistic nuclear reactions, π- - C (p beam = 40 GeV/c), Mg - Mg (p beam = 4.5 A GeV/c), and C - C (p beam = 4.2 A GeV/c), are compared by using Lorentz-invariant variables b ik . These variables are used to compare and classify nuclear reactions of various types in a wide range of energies. Different algorithms of clusters separation in the four-velocity space are compared. Experimental distributions are analyzed by means of invariant variables in the space to understand the difference of behaviour of particles and clusters for these reactions. Universal properties of hadron clusters are presented

  13. Description of charged particle multiplicity distribution in high energy strong interaction

    International Nuclear Information System (INIS)

    Qin Keyu

    1994-01-01

    With the assumption that the probability for n-charged particles production in hadron-hadron collision is Pn and proper choice of 1 , 2 , k and x in Pn, the true multiplicity distribution in full phase space can be described successfully at the centre of mass energy √S GeV. Using the experimental data of non singe-diffractive collisions between proton and antiproton at centre of mass energies of 200 and 900 GeV, the supposition has been examined and confirmed: it is very good to describe the facts. The theoretical bases of supposition were discussed

  14. Linking particle and pore-size distribution parameters to soil gas transport properties

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Møldrup, Per; Schjønning, Per

    2012-01-01

    Accurate estimation of soil gas diffusivity (Dp/Do, the ratio of gas diffusion coefficients in soil and free air) and air permeability (ka) from basic texture and pore characteristics will be highly valuable for modeling soil gas transport and emission and their field-scale variations. From......, respectively) and the Campbell water retention parameter b were used to characterize particle and pore size distributions, respectively. Campbell b yielded a wide interval (4.6–26.2) and was highly correlated with α, β, and volumetric clay content. Both Dp/Do and ka followed simple power-law functions (PLFs...

  15. Integral particle reflection coefficient for oblique incidence of photons as universal function in the domain of initial energies up to 300 keV

    Directory of Open Access Journals (Sweden)

    Ljubenov Vladan L.

    2014-01-01

    Full Text Available In this paper we present the results of calculations and analyses of the integral particle reflection coefficient of photons for oblique photon incidence on planar targets, in the domain of initial photon energies from 100 keV to 300 keV. The results are based on the Monte Carlo simulations of the photon reflection from water, concrete, aluminum, iron, and copper materials, performed by the MCNP code. It has been observed that the integral particle reflection coefficient as a function of the ratio of total cross-section of photons and effective atomic number of target material shows universal behavior for all the analyzed shielding materials in the selected energy domain. Analytical formulas for different angles of photon incidence have been proposed, which describe the reflection of photons for all the materials and energies analyzed.

  16. Estimating Soil Water Retention Curve Using The Particle Size Distribution Based on Fractal Approach

    Directory of Open Access Journals (Sweden)

    M.M. Chari

    2016-02-01

    Full Text Available Introduction: Water and soil retention curve is one of the most important properties of porous media to obtain in a laboratory retention curve and time associated with errors. For this reason, researchers have proposed techniques that help them to more easily acquired characteristic curve. One of these methods is the use of fractal geometry. Determining the relationship between particle size distribution fractal dimension (DPSD and fractal dimension retention curve (DSWRC can be useful. However, the full information of many soil data is not available from the grading curve and only three components (clay, silt and sand are measured.In recent decades, the use of fractal geometry as a useful tool and a bridge between the physical concept models and experimental parameters have been used.Due to the fact that both the solid phase of soil and soil pore space themselves are relatively similar, each of them can express different fractal characteristics of the soil . Materials and Methods: This study aims to determine DPSD using data soon found in the soil and creates a relationship between DPSD and DSWRC .To do this selection, 54 samples from Northern Iran and the six classes loam, clay loam, clay loam, sandy clay, silty loam and sandy loam were classified. To get the fractal dimension (DSWRC Tyler and Wheatcraft (27 retention curve equation was used.Alsothe fractal dimension particle size distribution (DPSD using equation Tyler and Wheatcraft (28 is obtained.To determine the grading curve in the range of 1 to 1000 micron particle radius of the percentage amounts of clay, silt and sand soil, the method by Skaggs et al (24 using the following equation was used. DPSD developed using gradation curves (Dm1 and three points (sand, silt and clay (Dm2, respectively. After determining the fractal dimension and fractal dimension retention curve gradation curve, regression relationship between fractal dimension is created. Results and Discussion: The results

  17. Method development and validation for measuring the particle size distribution of pentaerythritol tetranitrate (PETN) powders.

    Energy Technology Data Exchange (ETDEWEB)

    Young, Sharissa Gay

    2005-09-01

    Currently, the critical particle properties of pentaerythritol tetranitrate (PETN) that influence deflagration-to-detonation time in exploding bridge wire detonators (EBW) are not known in sufficient detail to allow development of a predictive failure model. The specific surface area (SSA) of many PETN powders has been measured using both permeametry and gas absorption methods and has been found to have a critical effect on EBW detonator performance. The permeametry measure of SSA is a function of particle shape, packed bed pore geometry, and particle size distribution (PSD). Yet there is a general lack of agreement in PSD measurements between laboratories, raising concerns regarding collaboration and complicating efforts to understand changes in EBW performance related to powder properties. Benchmarking of data between laboratories that routinely perform detailed PSD characterization of powder samples and the determination of the most appropriate method to measure each PETN powder are necessary to discern correlations between performance and powder properties and to collaborate with partnering laboratories. To this end, a comparison was made of the PSD measured by three laboratories using their own standard procedures for light scattering instruments. Three PETN powder samples with different surface areas and particle morphologies were characterized. Differences in bulk PSD data generated by each laboratory were found to result from variations in sonication of the samples during preparation. The effect of this sonication was found to depend on particle morphology of the PETN samples, being deleterious to some PETN samples and advantageous for others in moderation. Discrepancies in the submicron-sized particle characterization data were related to an instrument-specific artifact particular to one laboratory. The type of carrier fluid used by each laboratory to suspend the PETN particles for the light scattering measurement had no consistent effect on the resulting

  18. Comparison of Particle-Associated Bacteria from a Drinking Water Treatment Plant and Distribution Reservoirs with Different Water Sources

    NARCIS (Netherlands)

    Liu, G.; Ling, F.Q.; Van der Mark, E.J.; Zhang, X.D.; Knezev, A.; Verberk, J.Q.J.C.; Van der Meer, W.G.J.; Medema, G.J.; Liu, W.T.; Van Dijk, J.C.

    2016-01-01

    This study assessed the characteristics of and changes in the suspended particles and the associated bacteria in an unchlorinated drinking water distribution system and its reservoirs with different water sources. The results show that particle-associated bacteria (PAB) were present at a level of

  19. Cross-Sectional Information on Pore Structure and Element Distribution of Sediment Particles by SEM and EDS

    Directory of Open Access Journals (Sweden)

    Minghong Chen

    2017-01-01

    Full Text Available The interaction between pollutants and sediment particles often occurs on the particle surface, so surface properties directly affect surface reaction. The physical and chemical processes occurring on sediment particle surfaces are microscopic processes and as such need to be studied from a microscopic perspective. In this study, field emission scanning electron microscopy (SEM and energy dispersive X-ray spectrometer (EDS were adopted to observe and analyze the pore structure and element distribution of sediment particles. In particular, a special method of sample preparation was used to achieve the corresponding cross-sectional information of sediment particles. Clear images of a particle profile and pore microstructure were obtained by high-resolution SEM, while element distribution maps of sediment particles were obtained by EDS. The results provide an intuitive understanding of the internal microenvironment and external behavior of sediment particles, in addition to revealing a significant role of pore microstructure in the adsorption and desorption of pollutants. Thus, a combination of different experimental instruments and observation methods can provide real images and information on microscopic pore structure and element distribution of sediment particles. These results should help to improve our understanding of sediment dynamics and its environmental effects.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    Suspension of wear particles in gear oil with respect to the diversity of particle size combined with filter mechanisms has been analyzed. Coupling of wear modes from tribology is combined with particle size bins to show how a mathematical model can be expanded to include information gained from...... that particles less than 14 μm dominate the wear. Hence, it is concluded that abrasion dominate the wear, for the gear in operation, and it is concluded to be in quasi-stationary mode. The distribution of the particles is observed in conjunction with the particle quantity to determine a basis for normal...... operation. Limitations to the model in lack of fitting to large and frequent signal spikes are suggested to be caused by measurement equipment and/or model constraints. Predicting the transition from quasi-stationary (normal) mode to break-down mode is made possible by particle quantity detection as well...

  1. Emulsion Polymerization of Etyl Acrylate: The Effect of Surfactant, Initiator Concentration and PolymerizationTechnique on Particle Size Distribution

    OpenAIRE

    Nitri Arinda; Emil Budianto; Helmiyati

    2009-01-01

    Emulsion polymerization was conducted using ethyl acrylate monomer. Theeffect of sodium lauryl sulfate concentration, ammonium persulfate concentration, the various of polymerizationtechniques and feeding time to the conversion, particle size and its distribution were observed. The purpose of thisresearch is to obtain the optimum condition of ethyl acrylate homopolymer with particle size around 100 nm, to get theparticle size distribution monodisperse and to get solid content value of the exp...

  2. Fractal analysis of the effect of particle aggregation distribution on thermal conductivity of nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Wei, E-mail: weiw2015@gmail.com [Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074 (China); Cai, Jianchao, E-mail: caijc@cug.edu.cn [Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074 (China); Hu, Xiangyun, E-mail: xyhu@cug.edu.cn [Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074 (China); Han, Qi, E-mail: hanqi426@gmail.com [Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074 (China); Liu, Shuang, E-mail: lius@cug.edu.cn [Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074 (China); Zhou, Yingfang, E-mail: yingfang.zhou@abdn.ac.uk [School of Engineering, University of Aberdeen, FN 264, King' s College, Aberdeen, AB24 3UE (United Kingdom)

    2016-08-26

    A theoretical effective thermal conductivity model for nanofluids is derived based on fractal distribution characteristics of nanoparticle aggregation. Considering two different mechanisms of heat conduction including particle aggregation and convention, the model is expressed as a function of the fractal dimension and concentration. In the model, the change of fractal dimension is related to the variation of aggregation shape. The theoretical computations of the developed model provide a good agreement with the experimental results, which may serve as an effective approach for quantitatively estimating the effective thermal conductivity of nanofluids. - Highlights: • A thermal conductivity model is derived based on fractal aggregation distribution. • The relationship between aggregation shape and fractal dimension is analyzed. • Predictions of the proposed model show good agreement with experimental data.

  3. Single particle momentum and angular distributions in hadron-hadron collisions at ultrahigh energies

    Science.gov (United States)

    Chou, T. T.; Chen, N. Y.

    1985-01-01

    The forward-backward charged multiplicity distribution (P n sub F, n sub B) of events in the 540 GeV antiproton-proton collider has been extensively studied by the UA5 Collaboration. It was pointed out that the distribution with respect to n = n sub F + n sub B satisfies approximate KNO scaling and that with respect to Z = n sub F - n sub B is binomial. The geometrical model of hadron-hadron collision interprets the large multiplicity fluctuation as due to the widely different nature of collisions at different impact parameters b. For a single impact parameter b, the collision in the geometrical model should exhibit stochastic behavior. This separation of the stochastic and nonstochastic (KNO) aspects of multiparticle production processes gives conceptually a lucid and attractive picture of such collisions, leading to the concept of partition temperature T sub p and the single particle momentum spectrum to be discussed in detail.

  4. Design of shared unit-dose drug distribution network using multi-level particle swarm optimization.

    Science.gov (United States)

    Chen, Linjie; Monteiro, Thibaud; Wang, Tao; Marcon, Eric

    2018-03-01

    Unit-dose drug distribution systems provide optimal choices in terms of medication security and efficiency for organizing the drug-use process in large hospitals. As small hospitals have to share such automatic systems for economic reasons, the structure of their logistic organization becomes a very sensitive issue. In the research reported here, we develop a generalized multi-level optimization method - multi-level particle swarm optimization (MLPSO) - to design a shared unit-dose drug distribution network. Structurally, the problem studied can be considered as a type of capacitated location-routing problem (CLRP) with new constraints related to specific production planning. This kind of problem implies that a multi-level optimization should be performed in order to minimize logistic operating costs. Our results show that with the proposed algorithm, a more suitable modeling framework, as well as computational time savings and better optimization performance are obtained than that reported in the literature on this subject.

  5. Theory of localized bipolar wave-structures and nonthermal particle distributions in the auroral ionosphere

    Directory of Open Access Journals (Sweden)

    M. V. Goldman

    1999-01-01

    Full Text Available Bipolar wave structures and nonthermal particle distributions measured by the FAST satellite in regions of downward current are interpreted in terms of the nonlinear evolution of a two-stream instability. The instability results in holes, both in the electron distribution in phase space and in the electron density in real space. The wave potential energy, which traps the electrons, has a single minimum, and the associated electric field is bipolar. The early bipolar structures are coherent over hundreds of Debye lengths in the direction perpendicular to the magnetic field. After thousands of plasma periods the perpendicular coherence is lost, the structures break up, and electrostatic whistlers begin to dominate. Simulations and preliminary analysis of this breakup and emission process are presented.

  6. A Year-round Observation of Size Distribution of Aerosol Particles at the Cape Ochiishi, Japan

    Science.gov (United States)

    Miura, K.; Mukai, H.; Hashimoto, S.; Uematsu, M.

    2010-12-01

    New particle formation by nucleation of gas-phase compounds emitted from marine biogenic sources is very important for climate change. To clarify the mechanism of the formation, size distributions of submicron aerosols have been measured at the Cape Ochiishi, facing the North Western Pacific Ocean where primary productivity is high. A test observation was done from 22nd May to 18th June 2008 and a year-round observation has been performed from 16th October 2009 to 7th September 2010. The size distribution from 10 nm to 487 nm in diameter was measured with a scanning mobility particle sizer (SMPS, TSI 3034). Sample air was dried to lower than 40%. Transport of sulfate, organic carbon (OC), and black carbon (BC) was estimated with Chemical weather FORecasting System (CFORS), developed by Prof. Uno, Kyushu University, Japan. Existence of inversion layer was estimated with temperature profile measured at surface, 10m, 30m, and 50m in altitude. The burst of the particles smaller than 20nm in diameter continuing longer than 3 hrs was observed ten times until 3rd November 2009. Two were observed in early summer and the other was in autumn. Banana shape was faintly observed five times. Transport of sulfate, OC, and BC was observed 3, 8, 9 times, respectively. Source of air mass was estimated with these elements, weather map, and wind direction. Five air masses were estimated to continental. Clearly nucleation related to marine sources was not observed. The size distribution of burst evens of maritime and continental air mass showed the shift of mode to larger diameter. Strong inversion of temperature was observed once. The value of size distribution did not show high. Minimum value of size distribution was observed in the strong rain on 27th October. Acknowledgments This study was partly supported by the Grant-in-Aids for Scientific Research on Priority Areas from the Ministry of Education, Culture, Sports, Science and Technology, Japan (18067005). The observation was

  7. The stability of the ecological distribution of the incidence of treated mental disorders in the city of Mannheim.

    Science.gov (United States)

    Weyerer, S; Häfner, H

    1989-03-01

    In 1965, Häfner et al. (1969) conducted an ecological study of the incidence of treated mental disorders in the industrial city of Mannheim. They found large variations in incidence rates in 20 urban areas: excess morbidity in the socially disorganized areas located mainly in the city center, and low rates in areas on the outskirts. This study incorporates additional data from the Cumulative Psychiatric Case Register established in Mannheim in 1973. It focuses on the short- and long-term stability of the spatial distribution of mental disorders comparing the year 1965 with the period 1974-80, and analysing the individual years from 1974-80. Despite marked changes between 1965 and the seventies (the increase in the number of guest workers; the development of extensive building and urban renewal programs; the establishment of the Central Institute of Mental Health and several community psychiatric services after 1975), the ecological correlation remained relatively high (r = 0.79). Prior to the establishment of the Central Institute of Mental Health, the spatial distribution of mental disorders in the year 1974 was also very similar to that in 1965 (r = 0.73). In general, the study revealed a highly stable ecological distribution of treated mental disorders not only on a long-term basis, but also for the individual years from 1974 to 1980.

  8. Pesticides in the atmosphere: a comparison of gas-particle partitioning and particle size distribution of legacy and current-use pesticides

    Directory of Open Access Journals (Sweden)

    C. Degrendele

    2016-02-01

    Full Text Available This study presents a comparison of seasonal variation, gas-particle partitioning, and particle-phase size distribution of organochlorine pesticides (OCPs and current-use pesticides (CUPs in air. Two years (2012/2013 of weekly air samples were collected at a background site in the Czech Republic using a high-volume air sampler. To study the particle-phase size distribution, air samples were also collected at an urban and rural site in the area of Brno, Czech Republic, using a cascade impactor separating atmospheric particulates according to six size fractions. Major differences were found in the atmospheric distribution of OCPs and CUPs. The atmospheric concentrations of CUPs were driven by agricultural activities while secondary sources such as volatilization from surfaces governed the atmospheric concentrations of OCPs. Moreover, clear differences were observed in gas-particle partitioning; CUP partitioning was influenced by adsorption onto mineral surfaces while OCPs were mainly partitioning to aerosols through absorption. A predictive method for estimating the gas-particle partitioning has been derived and is proposed for polar and non-polar pesticides. Finally, while OCPs and the majority of CUPs were largely found on fine particles, four CUPs (carbendazim, isoproturon, prochloraz, and terbuthylazine had higher concentrations on coarse particles ( >  3.0 µm, which may be related to the pesticide application technique. This finding is particularly important and should be further investigated given that large particles result in lower risks from inhalation (regardless the toxicity of the pesticide and lower potential for long-range atmospheric transport.

  9. Modeling the Fate and Distribution of Floating Litter Particles in the Aegean Sea (E. Mediterranean

    Directory of Open Access Journals (Sweden)

    Dimitrios V. Politikos

    2017-06-01

    Full Text Available A circulation model is coupled to a Lagrangian particle-tracking model to simulate the transport floating litter particles in the Aegean Sea, Greece (Eastern Mediterranean. Considering different source regions and release dates, simulations were carried out to explore the fate and distribution of floating litter over 1990–2009, taking into account the seasonal and interannual variability of surface circulation. Model results depicted recurrently high concentrations of floating litter particles in the North Aegean plateau, the Saronikos Gulf, and along Evia and Crete islands. Modeled transport pathways of floating litter demonstrated that source regions are interconnected, with Saronikos Gulf being a main receptor of litter from other sources. Notably higher percent of litter exit (~35% than enter the model domain (~7% signified that Aegean Sea seems to act as a source rather than receptor of floating litter pollution in the Eastern Mediterranean Sea. Beached litter was found around 10%, mostly located in the western part of the Aegean Sea. This is the first modeling study to explore the transport of floating marine litter in Greek waters.

  10. Geodesic acoustic mode driven by energetic particles with bump-on-tail distribution

    Science.gov (United States)

    Ren, Haijun; Wang, Hao

    2018-04-01

    Energetic-particle-driven geodesic acoustic mode (EGAM) is analytically investigated by adopting the bump-on-tail distribution for energetic particles (EPs), which is created by the fact that the charge exchange time (τcx ) is sufficiently shorter than the slowing down time (τsl ). The dispersion relation is derived in the use of gyro-kinetic equations. Due to the finite ratio of the critical energy and the initial energy of EPs, defined as τc , the dispersion relation is numerically evaluated and the effect of finite τc is examined. Following relative simulation and experimental work, we specifically considered two cases: τsl/τcx = 3.4 and τsl/τcx = 20.4 . The pitch angle is shown to significantly enhance the growth rate and meanwhile, the real frequency is dramatically decreased with increasing pitch angle. The excitation of high-frequency EGAM is found, and this is consistent with both the experiment and the simulation. The number density effect of energetic particles, represented by \

  11. Transverse-momentum distribution of produced particles in ultrarelativistic nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    Ban-Hao, S.; Wong, C.

    1985-01-01

    In order to discern coherent or collective processes from incoherent processes in nucleus-nucleus reactions at high energies, we study the transverse-momentum distribution of the produced particles with an incoherent-multiple-collision model. In this model, the projectile nucleon makes successive inelastic collisions with nucleons in the target nucleus, the probability of such collisions being given by the thickness function and the nucleon-nucleon inelastic cross section. It is assumed that each baryon-baryon collision produces particles and degrades momenta just as a baryon-baryon collision in free space, and that there are no secondary collisions between the produced particles and the nucleons. We found that the average transverse momentum and the charged-multiplicity data at Fermilab and CERN ISR energies can be well explained by such a model. However, the average transverse momentum for some events observed by the Japanese-American cooperative emulsion experiment (JACEE) associated with large energy density in the central rapidity region differ markedly from the model results. Such a deviation indicates the presence of coherent or collective effects for these collisions and may indicate the possibility of a formation of quark-gluon plasma

  12. Variability of sub-micrometer particle number size distributions and concentrations in the Western Mediterranean regional background

    Directory of Open Access Journals (Sweden)

    Michael Cusack

    2013-02-01

    Full Text Available This study focuses on the daily and seasonal variability of particle number size distributions and concentrations, performed at the Montseny (MSY regional background station in the western Mediterranean from October 2010 to June 2011. Particle number concentrations at MSY were shown to be within range of various other sites across Europe reported in literature, but the seasonality of the particle number size distributions revealed significant differences. The Aitken mode is the dominant particle mode at MSY, with arithmetic mean concentrations of 1698 cm3, followed by the accumulation mode (877 cm−3 and the nucleation mode (246 cm−3. Concentrations showed a strong seasonal variability with large increases in particle number concentrations observed from the colder to warmer months. The modality of median size distributions was typically bimodal, except under polluted conditions when the size distribution was unimodal. During the colder months, the daily variation of particle number size distributions are strongly influenced by a diurnal breeze system, whereby the Aitken and accumulation modes vary similarly to PM1 and BC mass concentrations, with nocturnal minima and sharp day-time increases owing to the development of a diurnal mountain breeze. Under clean air conditions, high levels of nucleation and lower Aitken mode concentrations were measured, highlighting the importance of new particle formation as a source of particles in the absence of a significant condensation sink. During the warmer months, nucleation mode concentrations were observed to be relatively elevated both under polluted and clean conditions due to increased photochemical reactions, with enhanced subsequent growth owing to elevated concentrations of condensable organic vapours produced from biogenic volatile organic compounds, indicating that nucleation at MSY does not exclusively occur under clean air conditions. Finally, mixing of air masses between polluted and non

  13. Spatial Distribution of New Particle Formation over the Seoul Metropolitan Area during KORUS-AQ

    Science.gov (United States)

    Park, J.; Choi, Y.; Ghim, Y. S.; Seo, Y. K.; Choi, J. Y.; Lee, Y.; Kim, D. B.; Kang, K.; Chung, H.; Jung, J.

    2017-12-01

    Aerosol number size distributions were measured using a scanning mobility particle sizer (SMPS) at four selected sites in and around the Seoul Metropolitan Area (SMA) during the Korea-US Air Quality Study (KORUS-AQ) campaign from May to June 2016. Three sites are located within the SMA: Olympic Park (OP), Global Campus of the Hankuk University of Foreign Studies (HUFS), and Mt. Taehwa (MT), which are located about 14 km east-southeast, 35 km southeast, and 42 km southeast of the Seoul City Hall, respectively. The OP site is within a park ( 1.45 km2) surrounded by main roads. The HUFS site is in a valley sloping up to the east, and to the west, rural in character, with small-sized buildings, farmlands, and open spaces. The MT site is in the middle of forests, but an expressway runs in the southeast-northwest direction, about 2.6 km to the northeast. The Baengnyeong Island (BI) site, located about 210 km west-northwest of the Seoul City Hall. BI is considered a background and an upwind site of SMA, in contrast to HUFS and MT downwind of SMA, under prevailing northwesterlies. We investigated the spatial distribution of observed new particle formation (NPF) events to distinguish whether an event was local or regional. The evolutions of the episodes were accounted for in terms of precursor concentrations and meteorological variables, in association with the effects of long-range transport whenever it occurred.

  14. The distribution of cotransformed transgenes in particle bombardment-mediated transformed wheat.

    Science.gov (United States)

    Han, Yonghua; Blechl, Ann; Wang, Daowen

    2015-12-01

    Although particle bombardment is the predominant method of foreign DNA direct transfer, whether transgene is integrated randomly into the genome has not been determined. In this study, we identified the distribution of transgene loci in 45 transgenic wheat (Triticum aestivum L.) lines containing co-transformed high molecular weight glutenin subunit genes and the selectable marker bar using fluorescence in situ hybridization. Transgene loci were shown to distribute unevenly throughout the genome and incorporate into different locations along individual chromosomes. There was only a slight tendency towards the localization of transgenes in distal chromosome regions. High proportions of transgenes in separate plasmids integrated at the same site and only 7 lines had 2 or 3 loci. Such loci may not segregate frequently in subsequent generations so it is difficult to remove selectable markers from transgenic lines after regeneration. We also found that three transgene lines were associated with rearranged chromosomes, suggesting a the close relationship between particle bombardment-mediated transgene integration and chromosomal rearrangements.

  15. Particle Size Distributions Measured in the B757 Engine Plume During EXCAVATE

    Science.gov (United States)

    Sanders, Terry; Penko, Paul; Rivera, Monica; Culler, Steve

    2005-01-01

    The Experiment to Characterize Aircraft Volatile Aerosols and Trace Species Emissions (EXCAVATE) took place at NASA Langley Research Center during January 2002. This ground based study was conducted to examine the role of fuel sulfur content on particulate emissions. Size distributions as a function of engine operating conditions were measured in the exhaust plume of a B-757 at four downstream axial locations (1 m, 10 m, 25 m and 35 m). The engine was run on JP-5 with three different sulfur concentrations, 810 ppm, 1050 ppm, 1820 ppm; and was operated over a range of power settings from idle to near-full power. Zalabsky differential-mobility analyzers DMAS), Met One condensation-nuclei counters (CNCs), and a TSI 3022 condensation-particle counter (CPC) were used to measure the size distributions. The total number-count (particle concentration), number-based Emissions Index (EInumber) and mass-based Emissions Index (E1-J increased with fuel sulfur-content and engine pressure ratio (EPR). Count Mean Diameter (Ch4D) also increased with EPR yet remained fairly constant with fuel sulfur-content for a fixed location in the exhaust plume. Also the mode and CMD both increased with distance in the plume.

  16. Application of Dynamic Mutated Particle Swarm Optimization Algorithm to Design Water Distribution Networks

    Directory of Open Access Journals (Sweden)

    Kazem Mohammadi- Aghdam

    2015-10-01

    Full Text Available This paper proposes the application of a new version of the heuristic particle swarm optimization (PSO method for designing water distribution networks (WDNs. The optimization problem of looped water distribution networks is recognized as an NP-hard combinatorial problem which cannot be easily solved using traditional mathematical optimization techniques. In this paper, the concept of dynamic swarm size is considered in an attempt to increase the convergence speed of the original PSO algorithm. In this strategy, the size of the swarm is dynamically changed according to the iteration number of the algorithm. Furthermore, a novel mutation approach is introduced to increase the diversification property of the PSO and to help the algorithm to avoid trapping in local optima. The new version of the PSO algorithm is called dynamic mutated particle swarm optimization (DMPSO. The proposed DMPSO is then applied to solve WDN design problems. Finally, two illustrative examples are used for comparison to verify the efficiency of the proposed DMPSO as compared to other intelligent algorithms.

  17. Statistical theory on the analytical form of cloud particle size distributions

    Science.gov (United States)

    Wu, Wei; McFarquhar, Greg

    2017-11-01

    Several analytical forms of cloud particle size distributions (PSDs) have been used in numerical modeling and remote sensing retrieval studies of clouds and precipitation, including exponential, gamma, lognormal, and Weibull distributions. However, there is no satisfying physical explanation as to why certain distribution forms preferentially occur instead of others. Theoretically, the analytical form of a PSD can be derived by directly solving the general dynamic equation, but no analytical solutions have been found yet. Instead of using a process level approach, the use of the principle of maximum entropy (MaxEnt) for determining the analytical form of PSDs from the perspective of system is examined here. Here, the issue of variability under coordinate transformations that arises using the Gibbs/Shannon definition of entropy is identified, and the use of the concept of relative entropy to avoid these problems is discussed. Focusing on cloud physics, the four-parameter generalized gamma distribution is proposed as the analytical form of a PSD using the principle of maximum (relative) entropy with assumptions on power law relations between state variables, scale invariance and a further constraint on the expectation of one state variable (e.g. bulk water mass). DOE ASR.

  18. Parameter Estimation in Rainfall-Runoff Modelling Using Distributed Versions of Particle Swarm Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Michala Jakubcová

    2015-01-01

    Full Text Available The presented paper provides the analysis of selected versions of the particle swarm optimization (PSO algorithm. The tested versions of the PSO were combined with the shuffling mechanism, which splits the model population into complexes and performs distributed PSO optimization. One of them is a new proposed PSO modification, APartW, which enhances the global exploration and local exploitation in the parametric space during the optimization process through the new updating mechanism applied on the PSO inertia weight. The performances of four selected PSO methods were tested on 11 benchmark optimization problems, which were prepared for the special session on single-objective real-parameter optimization CEC 2005. The results confirm that the tested new APartW PSO variant is comparable with other existing distributed PSO versions, AdaptW and LinTimeVarW. The distributed PSO versions were developed for finding the solution of inverse problems related to the estimation of parameters of hydrological model Bilan. The results of the case study, made on the selected set of 30 catchments obtained from MOPEX database, show that tested distributed PSO versions provide suitable estimates of Bilan model parameters and thus can be used for solving related inverse problems during the calibration process of studied water balance hydrological model.

  19. Coagulation-agglomeration of fractal-like particles: structure and self-preserving size distribution.

    Science.gov (United States)

    Goudeli, Eirini; Eggersdorfer, Maximilian L; Pratsinis, Sotiris E

    2015-02-03

    Agglomeration occurs in environmental and industrial processes, especially at low temperatures where particle sintering or coalescence is rather slow. Here, the growth and structure of particles undergoing agglomeration (coagulation in the absence of coalescence, condensation, or surface growth) are investigated from the free molecular to the continuum regime by discrete element modeling (DEM). Particles coagulating in the free molecular regime follow ballistic trajectories described by an event-driven method, whereas in the near-continuum (gas-slip) and continuum regimes, Langevin dynamics describe their diffusive motion. Agglomerates containing about 10-30 primary particles, on the average, attain their asymptotic fractal dimension, D(f), of 1.91 or 1.78 by ballistic or diffusion-limited cluster-cluster agglomeration, corresponding to coagulation in the free molecular or continuum regimes, respectively. A correlation is proposed for the asymptotic evolution of agglomerate D(f) as a function of the average number of constituent primary particles, n̅(p). Agglomerates exhibit considerably broader self-preserving size distribution (SPSD) by coagulation than spherical particles: the number-based geometric standard deviations of the SPSD agglomerate radius of gyration in the free molecular and continuum regimes are 2.27 and 1.95, respectively, compared to ∼1.45 for spheres. In the transition regime, agglomerates exhibit a quasi-SPSD whose geometric standard deviation passes through a minimum at Knudsen number Kn ≈ 0.2. In contrast, the asymptotic D(f) shifts linearly from 1.91 in the free molecular regime to 1.78 in the continuum regime. Population balance models using the radius of gyration as collision radius underestimate (up to about 80%) the small tail of the SPSD and slightly overpredict the overall agglomerate coagulation rate, as they do not account for cluster interpenetration during coagulation. In the continuum regime, when a recently developed

  20. High-Resolution UV Relay Lens for Particle Size Distribution Measurements Using Holography

    International Nuclear Information System (INIS)

    Robert M. Malone, Brent C. Frogget, Morris I. Kaufman, Aric Tibbits, Gene A. Capelle, Mike Grover, Gerald D. Stevens, William D. Turley

    2008-01-01

    Shock waves passing through a metal sample can produce ejecta particulates at a metal-vacuum interface. Holography records particle size distributions by using a highpower, short-pulse laser to freeze particle motion. The sizes of the ejecta particles are recorded using an in-line Fraunhofer holography technique. Because the holographic plate would be destroyed in this energetic environment, a high-resolution lens has been designed to relay the interference fringes to a safe environment. Particle sizes within a 12-mm-diameter, 5-mm-thick volume are recorded on holographic film. To achieve resolution down to 0.5 microns, ultraviolet (UV) light (in this case supplied by a tripled Nd:YAG laser) is needed. The design and assembly of a nine-element lens that achieves >2000 lp/mm resolution and operates at f/0.85 will be described. To set up this lens system, a doublet lens is temporarily attached that enables operation with 532-nm (green) light and 1100 lp/mm resolution. Thus, the setup and alignment is performed with green light, but the dynamic recording is done with UV light. During setup, the 532-nm beam provides enough focus shift to accommodate the placement of a resolution pattern outside the ejecta volume; this resolution pattern does not interfere with the calibrated wires and pegs surrounding the ejecta volume. A television microscope archives images of resolution patterns that prove that the calibration wires, interference filter, holographic plate, and relay lenses are in their correct positions. Part of this lens is under vacuum, at the point where the laser illumination passes through a focus. Alignment and tolerancing of this high-resolution lens will be presented, and resolution variation through the 5-mm depth of field will be discussed

  1. Effect of indirect non-thermal plasma on particle size distribution and composition of diesel engine particles

    Science.gov (United States)

    Linbo, GU; Yixi, CAI; Yunxi, SHI; Jing, WANG; Xiaoyu, PU; Jing, TIAN; Runlin, FAN

    2017-11-01

    To explore the effect of the gas source flow rate on the actual diesel exhaust particulate matter (PM), a test bench for diesel engine exhaust purification was constructed, using indirect non-thermal plasma technology. The effects of different gas source flow rates on the quantity concentration, composition, and apparent activation energy of PM were investigated, using an engine exhaust particle sizer and a thermo-gravimetric analyzer. The results show that when the gas source flow rate was large, not only the maximum peak quantity concentrations of particles had a large drop, but also the peak quantity concentrations shifted to smaller particle sizes from 100 nm to 80 nm. When the gas source flow rate was 10 L min-1, the total quantity concentration greatly decreased where the removal rate of particles was 79.2%, and the variation of the different mode particle proportion was obvious. Non-thermal plasma (NTP) improved the oxidation ability of volatile matter as well as that of solid carbon. However, the NTP gas source rate had little effects on oxidation activity of volatile matter, while it strongly influenced the oxidation activity of solid carbon. Considering the quantity concentration and oxidation activity of particles, a gas source flow rate of 10 L min-1 was more appropriate for the purification of particles.

  2. Particle size distribution of main-channel-bed sediments along the upper Mississippi River, USA

    Science.gov (United States)

    Remo, Jonathan; Heine, Ruben A.; Ickes, Brian

    2016-01-01

    In this study, we compared pre-lock-and-dam (ca. 1925) with a modern longitudinal survey of main-channel-bed sediments along a 740-km segment of the upper Mississippi River (UMR) between Davenport, IA, and Cairo, IL. This comparison was undertaken to gain a better understanding of how bed sediments are distributed longitudinally and to assess change since the completion of the UMR lock and dam navigation system and Missouri River dams (i.e., mid-twentieth century). The comparison of the historic and modern longitudinal bed sediment surveys showed similar bed sediment sizes and distributions along the study segment with the majority (> 90%) of bed sediment samples having a median diameter (D50) of fine to coarse sand. The fine tail (≤ D10) of the sediment size distributions was very fine to medium sand, and the coarse tail (≥ D90) of sediment-size distribution was coarse sand to gravel. Coarsest sediments in both surveys were found within or immediately downstream of bedrock-floored reaches. Statistical analysis revealed that the particle-size distributions between the survey samples were statistically identical, suggesting no overall difference in main-channel-bed sediment-size distribution between 1925 and present. This was a surprising result given the magnitude of river engineering undertaken along the study segment over the past ~ 90 years. The absence of substantial differences in main-channel-bed-sediment size suggests that flow competencies within the highly engineered navigation channel today are similar to conditions within the less-engineered historic channel.

  3. Size distribution of interstellar particles. III. Peculiar extinctions and normal infrared extinction

    International Nuclear Information System (INIS)

    Mathis, J.S.; Wallenhorst, S.G.

    1981-01-01

    The effect of changing the upper and lower size limits of a distribution of bare graphite and silicate particles with n(a)αa/sup -q/ is investigated. Mathis, Rumpl, and Nordsieck showed that the normal extinction is matched very well by having the small-size cutoff, a/sub -/, roughly-equal0.005 or 0.01 μm, and the large size a/sub +/, about 0.25 μm, and q = 3.5 for both substances. We consider the progressively peculiar extinctions exhibited by the well-observed stars, sigma Sco, rho Oph, and theta 1 Ori C, with values of R/sub v/[equivalentA/sub v//E(B--V)] of 3.4, 4.4, and 5.5 compared to the normal 3.1. Two (sigma Sco, rho Oph) are in a neutral dense cloud; theta 1 Ori C is in the Orion Nebula. We find that sigma Sco has a normal graphite distribution but has had its small silicate particles removed, so that a/sub -/(sil)roughly-equal0.04 μm if q = 3.5, or q(sil) = 2.6 if the size limits are fixed. However, the upper size limit on silicates remains normal. In rho Oph, the graphite is still normal, but both a/sub -/(sil) and a/sub +/(sil) are increased, to about 0.04 μm and 0.4 or 0.5 μm, respectively, if q = 3.5, or q(sil)roughly-equal1.3 if the size limits are fixed. In theta 1 Ori, the small limit on graphite has increased to about 0.04 μm, or q(gra)roughly-equal3, while the silicates are about like those in rho Oph. The calculated lambda2175 bump is broader than the observed, but normal foreground extinction probably contributes appreciably to the observed bump. The absolute amount of extinction per H atom for rho Oph is not explained. The column density of H is so large that systematic effects might be present. Very large graphite particles (a>3 μm) are required to ''hide'' the graphite without overly affecting the visual extinction, but a normal (small) graphite size distribution is required by the lambda2175 bump. We feel that it is unlikely that such a bimodal distribution exists

  4. Effect of particle size frequency distribution of the substratum on the burrowing ability of Chiridota rigida (semper) (Echinodermata: holothuroidea)

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, J.M.; Murdoch, J.

    1977-01-01

    Chiridota rigida (Semper) burrows easily into well-sorted substrata, moving between particles in coarse substrata and pushing aside particles in fine substrata. Chiridota rigida does not burrow easily into poorly sorted substrata because spaces which can be penetrated are not available and because the particles cannot be moved as a result of increased stability of the substratum. In poorly sorted substrata, burrowing ability increases with increases in the proportion of fine particles. It would appear that the distribution and abundance of chiridota rigida and other chiridotids would be affected by the effect of the substratum on their ability to burrow.

  5. Improving the particle distribution and mechanical properties of friction-stir-welded composites by using a smooth pin tool

    Science.gov (United States)

    Liu, Huijie; Hu, Yanying; Zhao, Yunqiang; Fujii, Hidetoshi

    2017-09-01

    Friction stir welding (FSW) is a very promising technique for joining particle-reinforced aluminum-matrix composites (PRAMCs), but with increase in the volume fraction of reinforcing particles, their distribution in welds becomes inhomogeneous. This leads to an inconsistent deformation of welds and their destruction at low stresses. In order to improve the weld microstructure, a smooth pin tool was used for the friction stir welding of AC4A + 30 vol.% SiC particle-reinforced aluminum-matrix composites. The present work describes the effect of welding parameters on the characteristics of particle distribution and the mechanical properties of welds. The ultimate strength of weld reached, 309 MPa, was almost 190% of that of the basic material. The mechanism of SiC particle conglomeration is clearly illustrated by means of schematic illustrations.

  6. Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater — Using humic acid and iron nano-sized colloids as test particles

    DEFF Research Database (Denmark)

    Nielsen, Katrine; Kalmykova, Yuliya; Strömvall, Ann-Margret

    2015-01-01

    The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution...... to a higher extent in the Filtrated fractions. The highest concentrations of PAHs were present in the stormwater with the highest total suspended solids (TSS); the relative amount of the HMWPAHs was highest in the Particulate fractions (particles N 0.7 μm). The highest concentration of PAHs in the Colloidal...... fraction was found in the sample with occurrence of small nano-sized particles (b10 nm). The results show the importance of developing technologies that both can manage particulate matter and effectively remove PAHs present in the Colloidal and Dissolved fractions in stormwater. © 2015 Elsevier B.V. All...

  7. Abdominal Adiposity Distribution Quantified by Ultrasound Imaging and Incident Hypertension in a General Population

    DEFF Research Database (Denmark)

    Seven, Ekim; Thuesen, Betina H; Linneberg, Allan

    2016-01-01

    Abdominal obesity is a major risk factor for hypertension. However, different distributions of abdominal adipose tissue may affect hypertension risk differently. The main purpose of this study was to explore the association of subcutaneous abdominal adipose tissue (SAT) and visceral adipose tissue...

  8. incidence and distribution of insect pests in rain-fed wheat in eastern ...

    African Journals Online (AJOL)

    ACSS

    Insect pests are some of the major constraints limiting yield of wheat (Triticum aestivum L.) in East Africa. The objective of this study was to determine the species composition and distribution of insect pests, and their natural enemies associated with wheat in Eastern Africa. A survey was conducted in farmers' fields in ...

  9. Modeling optical properties of human skin using Mie theory for particles with different size distributions and refractive indices.

    Science.gov (United States)

    Bhandari, A; Hamre, B; Frette, Ø; Stamnes, K; Stamnes, J J

    2011-07-18

    We used size distributions of volume equivalent spherical particles with complex refractive index to model the inherent optical properties (IOPs) in four different layers of human skin at ten different wavelengths in the visible and near-infrared spectral bands. For each layer, we first computed the size-averaged absorption coefficient, scattering coefficient, and asymmetry factor for the collection of particles in a host medium using Mie theory and compared these IOPs in each layer with those obtained from a bio-optical model (BOM). This procedure was repeated, using an optimization scheme, until satisfactory agreement was obtained between the IOPs obtained from the particle size distribution and those given by the BOM. The size distribution as well as the complex refractive index of the particles, obtained from this modeling exercise, can be used to compute the phase matrix, which is an essential input to model polarized light transport in human skin tissue.

  10. Size distribution of aerosol particles produced during mining and processing uranium ore.

    Science.gov (United States)

    Mala, Helena; Tomasek, Ladislav; Rulik, Petr; Beckova, Vera; Hulka, Jiri

    2016-06-01

    The aerosol particle size distributions of uranium and its daughter products were studied and determined in the area of the Rožná mine, which is the last active uranium mine in the Czech Republic. A total of 13 samples were collected using cascade impactors from three sites that had the highest expected levels of dust, namely, the forefield, the end of the ore chute and an area close to workers at the crushing plant. The characteristics of most size distributions were very similar; they were moderately bimodal, with a boundary approximately 0.5 μm between the modes. The activity median aerodynamic diameter (AMAD) and geometric standard deviation (GSD) were obtained from the distributions beyond 0.39 μm, whereas the sizes of particles below 0.39 μm were not differentiated. Most AMAD and GSD values in the samples ranged between 3.5 and 10.5 μm and between 2.8 and 5.0, respectively. The geometric means of the AMADs and GSDs from all of the underground sampling sites were 4.2 μm and 4.4, respectively, and the geometric means of the AMADs and GSDs for the crushing plant samplings were 9.8 μm and 3.3, respectively. The weighted arithmetic mean of the AMADs was 4.9 μm, with a standard error of 0.7 μm, according to the numbers of workers at the workplaces. The activity proportion of the radon progeny to (226)Ra in the aerosol was 0.61. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Retrieval of spheroid particle size distribution from spectral extinction data in the independent mode using PCA approach

    International Nuclear Information System (INIS)

    Tang, Hong; Lin, Jian-Zhong

    2013-01-01

    An improved anomalous diffraction approximation (ADA) method is presented for calculating the extinction efficiency of spheroids firstly. In this approach, the extinction efficiency of spheroid particles can be calculated with good accuracy and high efficiency in a wider size range by combining the Latimer method and the ADA theory, and this method can present a more general expression for calculating the extinction efficiency of spheroid particles with various complex refractive indices and aspect ratios. Meanwhile, the visible spectral extinction with varied spheroid particle size distributions and complex refractive indices is surveyed. Furthermore, a selection principle about the spectral extinction data is developed based on PCA (principle component analysis) of first derivative spectral extinction. By calculating the contribution rate of first derivative spectral extinction, the spectral extinction with more significant features can be selected as the input data, and those with less features is removed from the inversion data. In addition, we propose an improved Tikhonov iteration method to retrieve the spheroid particle size distributions in the independent mode. Simulation experiments indicate that the spheroid particle size distributions obtained with the proposed method coincide fairly well with the given distributions, and this inversion method provides a simple, reliable and efficient method to retrieve the spheroid particle size distributions from the spectral extinction data. -- Highlights: ► Improved ADA is presented for calculating the extinction efficiency of spheroids. ► Selection principle about spectral extinction data is developed based on PCA. ► Improved Tikhonov iteration method is proposed to retrieve the spheroid PSD.

  12. SILICON CARBIDE GRAIN BOUNDARY DISTRIBUTIONS, IRRADIATION CONDITIONS, AND SILVER RETENTION IN IRRADIATED AGR-1 TRISO FUEL PARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    Lillo, T. M.; Rooyen, I. J.; Aguiar, J. A.

    2016-11-01

    Precession electron diffraction in the transmission electron microscope was used to map grain orientation and ultimately determine grain boundary misorientation angle distributions, relative fractions of grain boundary types (random high angle, low angle or coincident site lattice (CSL)-related boundaries) and the distributions of CSL-related grain boundaries in the SiC layer of irradiated TRISO-coated fuel particles. Two particles from the AGR-1 experiment exhibiting high Ag-110m retention (>80%) were compared to a particle exhibiting low Ag-110m retention (<19%). Irradiated particles with high Ag-110m retention exhibited a lower fraction of random, high angle grain boundaries compared to the low Ag-110m retention particle. An inverse relationship between the random, high angle grain boundary fraction and Ag-110m retention is found and is consistent with grain boundary percolation theory. Also, comparison of the grain boundary distributions with previously reported unirradiated grain boundary distributions, based on SEM-based EBSD for similarly fabricated particles, showed only small differences, i.e. a greater low angle grain boundary fraction in unirradiated SiC. It was, thus, concluded that SiC layers with grain boundary distributions susceptible to Ag-110m release were present prior to irradiation. Finally, irradiation parameters were found to have little effect on the association of fission product precipitates with specific grain boundary types.

  13. 3D Nondestructive Visualization and Evaluation of TRISO Particles Distribution in HTGR Fuel Pebbles Using Cone-Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Gongyi Yu

    2017-01-01

    Full Text Available A nonuniform distribution of tristructural isotropic (TRISO particles within a high-temperature gas-cooled reactor (HTGR pebble may lead to excessive thermal gradients and nonuniform thermal expansion during operation. If the particles are closely clustered, local hotspots may form, leading to excessive stresses on particle layers and an increased probability of particle failure. Although X-ray digital radiography (DR is currently used to evaluate the TRISO distributions in pebbles, X-ray DR projection images are two-dimensional in nature, which would potentially miss some details for 3D evaluation. This paper proposes a method of 3D visualization and evaluation of the TRISO distribution in HTGR pebbles using cone-beam computed tomography (CBCT: first, a pebble is scanned on our high-resolution CBCT, and 2D cross-sectional images are reconstructed; secondly, all cross-sectional images are restructured to form the 3D model of the pebble; then, volume rendering is applied to segment and display the TRISO particles in 3D for visualization and distribution evaluation. For method validation, several pebbles were scanned and the 3D distributions of the TRISO particles within the pebbles were produced. Experiment results show that the proposed method provides more 3D than DR, which will facilitate pebble fabrication research and production quality control.

  14. Gas-solute dispersivity ratio in granular porous media as related to particle size distribution and particle shape

    DEFF Research Database (Denmark)

    Pugliese, Lorenzo; Poulsen, Tjalfe; Straface, Salvatore

    2013-01-01

    Measurements of solute dispersion in porous media is generally much more time consuming than gas dispersion measurements performed under equivalent conditions. Significant time savings may therefore, be achieved if solute dispersion coefficients can be estimated based on measured gas dispersion...... data. This paper evaluates the possibility for estimating solute dispersion based on gas dispersion measurements. Breakthrough measurements were carried out at different fluid velocities (covering the same range in Reynolds number), using O2 and NaCl as gas and solute tracers, respectively. Three...... different, granular porous materials were used: (1) crushed granite (very angular particles), (2) gravel (particles of intermediate roundness) and (3) Leca® (almost spherical particles). For each material, 21 different particle size fractions were used. Gas and solute dispersion coefficients were determined...

  15. Saturated Particle Transport in Porous Media: An Investigation into the Influence of Flow Direction and Particle Size Distribution

    Science.gov (United States)

    2015-06-28

    Excitation of particles was made using a 300W/120V halogen light bulb coupled with an excitation filter corresponding to the particles...Number: Jianqing Du 1 NAME Total Number: ...... ...... Sub Contractors (DD882) Names of other research staff Inventions (DD882) Scientific Progress See...points. Due to light scattering the fluorescent light intensity at one location is not only determined by its concentration but also by its

  16. Concentrations, size distributions and temporal variations of fluorescent biological aerosol particles in southern tropical India

    Science.gov (United States)

    Valsan, Aswathy; Krishna R, Ravi; CV, Biju; Huffman, Alex; Poschl, Ulrich; Gunthe, Sachin

    2015-04-01

    Biological aerosols constitute a wide range of dead and alive biological materials and structures that are suspended in the atmosphere. They play an important role in the atmospheric physical, chemical and biological processes and health of living being by spread of diseases among humans, plants, and, animals. The atmospheric abundance, sources, physical properties of PBAPs as compared to non-biological aerosols, however, is poorly characterized. The Indian tropical region, where large fraction of the world's total population is residing, experiences a distinctive meteorological phenomenon by means of Indian Summer Monsoon (IMS). Thus, the properties and characteristics of biological aerosols are also expected to be very diverse over the Indian subcontinent depending upon the seasons. Here we characterize the number concentration and size distribution of Fluorescent Biological Aerosol Particles (FBAP) at a high altitude continental site, Munnar (10.09 N, 77.06 E; 1605 m asl) in South India during the South-West monsoon, which constitute around 80 percent of the annual rainfall in Munnar. Continuous three months measurements (from 01 June 2014 to 21 Aug 2104) FBAPs were carried out at Munnar using Ultra Violet Aerodynamic Particle Sizer (UVAPS) during IMS. The mean number and mass concentration of coarse FBAP averaged over the entire campaign was 1.7 x 10-2 cm-3 and 0.24 µg m-3 respectively, which corresponds to 2 percent and 6 percent of total aerosol particle number and mass concentration. In agreement to other previous measurements the number size distribution of FBAP also peaks at 3.2 micron indicating the strong presence of fungal spores. This was also supported by the Scanning Electron Microscopic analysis of bioaerosols on filter paper. They also displayed a strong diurnal cycle with maximum concentration occurring at early morning hours. During periods of heavy and continuous rain where the wind is consistently blowing from South-West direction it was

  17. Pair distribution functions of colloidal particles on a quartz collector in a parallel plate and stagnation point flow chamber

    NARCIS (Netherlands)

    Yang, JL; Busscher, HJ; Bos, R.R.M.

    2000-01-01

    Pair distribution functions of polystyrene particles adhering on a quartz collector surface are compared for a parallel plate (PP) and stagnation point (SP) flow chamber at a common Peclet number and identical surface coverage. Radial pair distribution functions of deposition patterns around the

  18. Is the Field of Numbers a Real Physical Field? On the Frequent Distribution and Masses of the Elementary Particles

    Directory of Open Access Journals (Sweden)

    Belyakov A. V.

    2010-04-01

    Full Text Available Frequent distributions of the databases of the numerical values obtained by resolving algorithms, which describe physical and other processes, give a possibility for bonding the probability of that results the algorithms get. In the frequent distribution of the fractions of integers (rational numbers, local maxima which meet the ratios of masses of the elementary particles have been found.

  19. New Measurements of the Particle Size Distribution of Apollo 11 Lunar Soil 10084

    Science.gov (United States)

    McKay, D.S.; Cooper, B.L.; Riofrio, L.M.

    2009-01-01

    We have initiated a major new program to determine the grain size distribution of nearly all lunar soils collected in the Apollo program. Following the return of Apollo soil and core samples, a number of investigators including our own group performed grain size distribution studies and published the results [1-11]. Nearly all of these studies were done by sieving the samples, usually with a working fluid such as Freon(TradeMark) or water. We have measured the particle size distribution of lunar soil 10084,2005 in water, using a Microtrac(TradeMark) laser diffraction instrument. Details of our own sieving technique and protocol (also used in [11]). are given in [4]. While sieving usually produces accurate and reproducible results, it has disadvantages. It is very labor intensive and requires hours to days to perform properly. Even using automated sieve shaking devices, four or five days may be needed to sieve each sample, although multiple sieve stacks increases productivity. Second, sieving is subject to loss of grains through handling and weighing operations, and these losses are concentrated in the finest grain sizes. Loss from handling becomes a more acute problem when smaller amounts of material are used. While we were able to quantitatively sieve into 6 or 8 size fractions using starting soil masses as low as 50mg, attrition and handling problems limit the practicality of sieving smaller amounts. Third, sieving below 10 or 20microns is not practical because of the problems of grain loss, and smaller grains sticking to coarser grains. Sieving is completely impractical below about 5- 10microns. Consequently, sieving gives no information on the size distribution below approx.10 microns which includes the important submicrometer and nanoparticle size ranges. Finally, sieving creates a limited number of size bins and may therefore miss fine structure of the distribution which would be revealed by other methods that produce many smaller size bins.

  20. Experimental Study on Characteristics of Oil Particle Distribution in Water-Gelled Crude Oil Two-Phase Flow System

    Directory of Open Access Journals (Sweden)

    Liu Xiaoyan

    2014-06-01

    Full Text Available The conventional gathering and transportation mode of heating the produced fluid of oil wells with hot water or steam may result in excessive energy consumption. In order to perform the unheated transportation, the idea of hydraulic suspension transport of the gelled crude oil is proposed based on the actual production of Daqing Oilfield, and the experimental system is established to test characteristics of oil particle distribution which have an important effect on the hydraulic suspension transportation. In the experiment, the image of gelled crude oil particle distribution was obtained in a horizontal pipe with inner diameter of 0.053 m, and then the law of particle distribution was investigated by the theoretical model. The results showed that the gelled crude oil hydraulic suspension transport could be achieved without any chemical reagent when the gelled crude oil was transformed into particles and dispersedly suspended in water. The results also showed that the gelled oil particles of 0–4 mm in size accounted for 92% or more of all particles, and the percentage of gelled crude oil particles of a size of 4 mm gradually increased with the increasing mixed flow rate.

  1. A systematics of optical model compound nucleus formation cross sections for neutrons, proton, deuteron, 3He and alpha particle incidents

    International Nuclear Information System (INIS)

    Murata, Toru

    2000-01-01

    Simple formulae to reproduce the optical model compound nucleus formation cross sections for neutron, proton, deuteron, triton, 3 He and alpha particles are presented for target nuclei of light to medium weight mass region. (author)

  2. Size distribution of airborne particle-bound polybrominated diphenyl ethers and its implications for dry and wet deposition.

    Science.gov (United States)

    Luo, Pei; Ni, Hong-Gang; Bao, Lian-Jun; Li, Shao-Meng; Zeng, Eddy Y

    2014-12-02

    Size distribution of particles in part dictates the environmental behavior of particle-bound organic pollutants in the atmosphere. The present study was conducted to examine the potential mechanisms responsible for the distribution of organic pollutants in size fractionated particles and their environmental implications, using an e-waste recycling zone in South China as a case study. Size-fractionated atmospheric particles were collected at the heights of 1.5, 5, and 20 m near two residential apartments and analyzed for polybrominated diphenyl ethers (PBDEs). The concentrations of particle-bound ΣPBDE (sum of 18 PBDE congeners) were significantly greater at 5 and 20 m than those at 1.5 m. The size-fractionated distributions of airborne ΣPBDE displayed trimodal peaks in 0.10–0.18, 1.8–3.2, and 10–18 μm at 1.5 m but only an unimodal peak in 1.0–1.8 μm at 20 m height. Emission sources, resuspension of dust and soil, and volatility of PBDEs were important factors influencing the size distribution of particle-bound PBDEs. The dry deposition fluxes of particle-bound PBDE estimated from the measured data in the present study were approximately twice the estimated wet deposition fluxes, with a total deposition flux of 3000 ng m(–2) d(–1). The relative contributions of particles to dry and wet deposition fluxes were also size-dependent, e.g., coarse (aerodynamic diameters (Dp) > 1.8 μm) and fine (Dp < 1.8 μm) particles dominated the dry and wet deposition fluxes of PBDEs, respectively.

  3. Hysteresis in suspended sediment to turbidity relations due to changing particle size distributions

    Science.gov (United States)

    Landers, Mark N.; Sturm, Terry W.

    2013-01-01

    Turbidity (T) is the most ubiquitous of surrogate technologies used to estimate suspended-sediment concentration (SSC). The effects of sediment size on turbidity are well documented; however, effects from changes in particle size distributions (PSD) are rarely evaluated. Hysteresis in relations of SSC-to-turbidity (SSC~T) for single stormflow events was observed and quantified for a data set of 195 concurrent measurements of SSC, turbidity, discharge, velocity, and volumetric PSD collected during five stormflows in 2009–2010 on Yellow River at Gees Mill Road in metropolitan Atlanta, Georgia. Regressions of SSC-normalized turbidity (T/SSC) on concurrently measured PSD percentiles show an inverse, exponential influence of particle size on turbidity that is not constant across the size range of the PSD. The majority of the influence of PSD on T/SSC is from particles of fine-silt and smaller sizes (finer than 16 microns). This study shows that small changes in the often assumed stability of the PSD are significant to SSC~T relations. Changes of only 5 microns in the fine silt and smaller size fractions of suspended sediment PSD can produce hysteresis in the SSC~T rating that can increase error and produce bias. Observed SSC~T hysteresis may be an indicator of changes in sediment properties during stormflows and of potential changes in sediment sources. Trends in the PSD time series indicate that sediment transport is capacity-limited for sand-sized sediment in the channel and supply-limited for fine silt and smaller sediment from the hillslope.

  4. Impact of roadside noise barriers on particle size distributions and pollutants concentrations near freeways

    Science.gov (United States)

    Ning, Zhi; Hudda, Neelakshi; Daher, Nancy; Kam, Winnie; Herner, Jorn; Kozawa, Kathleen; Mara, Steven; Sioutas, Constantinos

    2010-08-01

    Increasing epidemiological evidence has established an association between a host of adverse health effects and exposure to ambient particulate matter (PM) and co-pollutants, especially those emitted from motor vehicles. Although PM and their co-pollutants dispersion profiles near the open freeway have been extensively characterized by means of both experimental measurements and numerical simulations in recent years, such investigations near freeways with roadside barriers have not been well documented in the literature. A few previous studies suggested that the presence of roadside structures, such as noise barriers and vegetation, may impact the decay of pollutant concentrations downwind of the freeway by limiting the initial dispersion of traffic emissions and increasing their vertical mixing due to the upward deflection of airflow. Since the noise barriers are now common roadside features of the freeways, particularly those running through populated urban areas, it is pertinent to investigate the impact of their presence on the particles and co-pollutants concentrations in areas adjacent to busy roadways. This study investigated two highly trafficked freeways (I-710 and I-5) in Southern California, with two sampling sites for each freeway, one with and the other without the roadside noise barriers. Particle size distributions and co-pollutants concentrations were measured in the immediate proximity of freeways and at different distances downwind of the freeways. The results showed the formation of a "concentration deficit" zone in the immediate vicinity of the freeway with the presence of roadside noise barrier, followed by a surge of pollutant concentrations further downwind at 80-100 m away from freeway. The particle and co-pollutants concentrations reach background levels at farther distances of 250-400 m compared to 150-200 m at the sites without roadside noise barriers.

  5. Laser Diffraction Techniques Replace Sieving for Lunar Soil Particle Size Distribution Data

    Science.gov (United States)

    Cooper, Bonnie L.; Gonzalez, C. P.; McKay, D. S.; Fruland, R. L.

    2012-01-01

    Sieving was used extensively until 1999 to determine the particle size distribution of lunar samples. This method is time-consuming, and requires more than a gram of material in order to obtain a result in which one may have confidence. This is demonstrated by the difference in geometric mean and median for samples measured by [1], in which a 14-gram sample produced a geometric mean of approx.52 micrometers, whereas two other samples of 1.5 grams resulted in gave means of approx.63 and approx.69 micrometers. Sample allocations for sieving are typically much smaller than a gram, and many of the sample allocations received by our lab are 0.5 to 0.25 grams in mass. Basu [2] has described how the finest fraction of the soil is easily lost in the sieving process, and this effect is compounded when sample sizes are small.

  6. Auto-radiographical study of activity distribution of high-dispersity hot particles from NPP

    International Nuclear Information System (INIS)

    Bonchev, Ts.; Andreev, Ts.; Todorov, N.; Andreev, P.; Kasabov, I.

    1995-01-01

    Autoradiograms of hot particles (HP) detected at Kozloduy NPP have been obtained with ordinary photographic film using direct contact. HP diameter and activity have been calculated by computer processing of the image.The distribution of HP weight and the precipitation time on surfaces has been estimated. Results on 37 HP found at the Kozloduy NPP units 1-4 and 9 HP found in special rooms containing waste are reported. The emitters are identified as 60 Co, 54 Mn and α emitters with specific activities 2.10 8 Bq/g, 2.10 7 Bq/g and 3.10 4 Bq/g respectively. 5 refs., 6 figs., 3 tabs

  7. Particle size distribution of brominated flame retardants in house dust from Japan

    Directory of Open Access Journals (Sweden)

    Natsuko Kajiwara

    2016-06-01

    Full Text Available The present study was conducted to examine the concentrations, profiles, and mass distributions of polybrominated diphenyl ethers (PBDEs, hexabromocyclododecanes (HBCDs, and polybrominated dibenzo-p-dioxins/furans (PBDD/Fs based on the particle sizes of house dust samples from five homes in Japan. After removal of impurities from house dust from vacuum cleaner bags, selected indoor dust samples were size fractionated (>2 mm, 1–2 mm, 0.5–1 mm, 250–500 μm, 106–250 μm, 53–106 μm, and 250 μm in size and fluffy dust were included. The conclusion is that particulate dust <250 μm in size without fluffy dust should be used to analyze dust for brominated flame retardants.

  8. Experimental study of the density distribution of the particles of the material in screw installation

    Directory of Open Access Journals (Sweden)

    Demidov S. F.

    2017-02-01

    Full Text Available the experimental studies of density distribution of the particles of a mixture of wheat, oats, rye to feed pigs by infrared heating at the time of stay and temperature at the exit of the installation. The purpose of the work is to study the quality of treatment of the product with the settings with the screw and the screw with installed round jumper on the pen of the screw. Screw installations with infrared emitters of selected wavelength give the opportunity for intense and continuous heat treatment process. The authors used the optimal parameters of the process with the screw and the screw with installed round jumper on the pen of the screw. The parameters of screw installation during the study were the following: the number of revolutions of the screw was 10 rpm, density of heat flux was 12 kW/m2, output capacity – 250 kg/h.

  9. Inclusive transverse momentum distributions of charged particles in diffractive and non-diffractive photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-03-01

    Inclusive transverse momentum spectra of charged particles in photoproduction events in the laboratory pseudorapidity range -1.2 T =8 GeV using the ZEUS detector. Diffractive and non-diffractive reactions have been selected with an average γp centre of mass (c.m.) energy of =180 GeV. For diffractive reactions, the p T spectra of the photon dissociation events have been measured in two intervals of the dissociated photon mass with mean values X >=5 GeV and 10 GeV. The inclusive transverse momentum spectra fall exponentially in the low p T region. The non-diffractive data show a pronounced high p T tail departing from the exponential shape. The p T distributions are compared to lower energy photoproduction data and to hadron-hadron collisions at a similar c.m. energy. The data are also compared to the results of a next-to-leading order QCD calculation. (orig.)

  10. A multi-objective particle swarm optimization for production-distribution planning in supply chain network

    Directory of Open Access Journals (Sweden)

    Alireza Pourrousta

    2012-04-01

    Full Text Available Integrated supply chain includes different components of order, production and distribution and it plays an important role on reducing the cost of manufacturing system. In this paper, an integrated supply chain in a form of multi-objective decision-making problem is presented. The proposed model of this paper considers different parameters with uncertainty using trapezoid numbers. We first implement a ranking method to covert the fuzzy model into a crisp one and using multi-objective particle swarm optimization, we solve the resulted model. The results are compared with the performance of NSGA-II for some randomly generated problems and the preliminary results indicate that the proposed model of the paper performs better than the alternative method.

  11. Preparation of Parium Titanates With Different Particle Size Distribution Using Modified Pechini Method

    Directory of Open Access Journals (Sweden)

    Ahmed Jaafer Abed AL-Jabar

    2017-03-01

    Full Text Available Barium titanates is one of the most important ceramics that are widely used in the electronic industry because of its high dielectric constant, its ferroelectricity, and its piezoelectric properties. In the current study, five different batches of barium titanate powders were prepared by modifiedpechini method using the barium chloride and the titanium chloride as a starting materials in order to obtain different particle size distributions.SEM, TGA, DTA, XRD, FTIR, and other techniques have been used to characterize the prepared samples.XRD results suggested that the synthesized BaTiO3has a tetragonal phase.SEM images of the prepared samples reveala polyhedron shapes, on average, also it show that there are markedinfluence of the reactant concentration on the average size of the grains,where the samples prepared from higher solution concentration tend to possess larger grain size compared to that prepared from low concentration.

  12. Vacuum Simulations in High Energy Accelerators and Distribution Properties of Continuous and Discrete Particle Motions

    CERN Document Server

    Aichinger, Ida; Kersevan, Roberto

    The underlying thesis on mathematical simulation methods in application and theory is structured into three parts. The first part sets up a mathematical model capable of predicting the performance and operation of an accelerator’s vacuum system based on analytical methods. A coupled species-balance equation system describes the distribution of the gas dynamics in an ultra-high vacuum system considering impacts of conductance limitations, beam induced effects (ion-, electron-, and photon-induced de- sorption), thermal outgassing and sticking probabilities of the chamber materials. A new solving algorithm based on sparse matrix representations, is introduced and presents a closed form solution of the equation system. The model is implemented in a Python environment, named PyVasco, and is supported by a graphical user interface to make it easy available for everyone. A sensitivity analysis, a cross-check with the Test-Particle Monte Carlo simulation program Molflow+ and a comparison of the simulation results t...

  13. Mathematical modeling of pigment dispersion taking into account the full agglomerate particle size distribution

    DEFF Research Database (Denmark)

    Kiil, Søren

    2017-01-01

    The purpose of this work is to develop a mathematical model that can quantify the dispersion of pigments, with a focus on the mechanical breakage of pigment agglomerates. The underlying physical mechanism was assumed to be surface erosion of spherical pigment agglomerates. The full agglomerate......-based acrylic vehicle in a three-roll mill. When the linear rate of agglomerate surface erosion was taken to be proportional to the external agglomerate surface area, simulations of the volume-moment mean diameter over time were in good quantitative agreement with experimental data for all three pigments....... The only adjustable parameter used was an apparent rate constant for the linear agglomerate erosion rate. Model simulations, at selected values of time, for the full agglomerate particle size distribution were in good qualitative agreement with the measured values. A quantitative match of the experimental...

  14. Methods for obtaining true particle size distributions from cross section measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lord, Kristina Alyse [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    Sectioning methods are frequently used to measure grain sizes in materials. These methods do not provide accurate grain sizes for two reasons. First, the sizes of features observed on random sections are always smaller than the true sizes of solid spherical shaped objects, as noted by Wicksell [1]. This is the case because the section very rarely passes through the center of solid spherical shaped objects randomly dispersed throughout a material. The sizes of features observed on random sections are inversely related to the distance of the center of the solid object from the section [1]. Second, on a plane section through the solid material, larger sized features are more frequently observed than smaller ones due to the larger probability for a section to come into contact with the larger sized portion of the spheres than the smaller sized portion. As a result, it is necessary to find a method that takes into account these reasons for inaccurate particle size measurements, while providing a correction factor for accurately determining true particle size measurements. I present a method for deducing true grain size distributions from those determined from specimen cross sections, either by measurement of equivalent grain diameters or linear intercepts.

  15. The influence of the fractal particle size distribution on the mobility of dry granular materials

    Directory of Open Access Journals (Sweden)

    Vallejo Luis E.

    2017-01-01

    Full Text Available This study presents an experimental analysis on the influence of the particle size distribution (psd on the mobility of dry granular materials. The psd obeys a power law of the form: N(L>d=kd-Df, where N is the number of particles with diameter L greater than a given diameter d, k is a proportionality constant, and Df is the fractal dimension of the psd. No laboratory or numerical study has been conducted to date analysing how a fractal psd influences the mobility of granular flows as in the case of rock avalanches. In this study, the flow characteristics of poly-dispersed granular materials that have a fractal psd were investigated in the laboratory. Granular mixtures having different fractal psd values were placed in a hollow cylinder. The cylinder was lifted and the distance of flow of the mixture was measured with respect to the original position of the cylinder. It was determined that the distance of flow of the mixtures was directly related to their fractal psd values. That is, the larger the distance of flow of the mixture, the larger is the fractal psd of the granular mixture tested. Thus, the fractal psd in dry granular mixtures seems to have a large influence on the easiness by which dry granular mixtures move in the field.

  16. Hybrid particle swarm optimization with Cauchy distribution for solving reentrant flexible flow shop with blocking constraint

    Directory of Open Access Journals (Sweden)

    Chatnugrob Sangsawang

    2016-06-01

    Full Text Available This paper addresses a problem of the two-stage flexible flow shop with reentrant and blocking constraints in Hard Disk Drive Manufacturing. This problem can be formulated as a deterministic FFS|stage=2,rcrc, block|Cmax problem. In this study, adaptive Hybrid Particle Swarm Optimization with Cauchy distribution (HPSO was developed to solve the problem. The objective of this research is to find the sequences in order to minimize the makespan. To show their performances, computational experiments were performed on a number of test problems and the results are reported. Experimental results show that the proposed algorithms give better solutions than the classical Particle Swarm Optimization (PSO for all test problems. Additionally, the relative improvement (RI of the makespan solutions obtained by the proposed algorithms with respect to those of the current practice is performed in order to measure the quality of the makespan solutions generated by the proposed algorithms. The RI results show that the HPSO algorithm can improve the makespan solution by averages of 14.78%.

  17. Particle size distribution of dust collected from Alcator C-MOD

    International Nuclear Information System (INIS)

    Gorman, S.V.; Carmack, W.J.; Hembree, P.B.

    1998-01-01

    There are important safety issues associated with tokamak dust, accumulated primarily from sputtering and disruptions. The dust may contain tritium, it may be activated, chemically toxic, and chemically reactive. The purpose of this paper is to present results from analyses of particulate collected from the Alcator C-MOD tokamak located at Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts. The sample obtained from C-MOD was not originally intended for examination outside of MIT. The sample was collected with the intent of performing only a composition analysis. However, MIT provided the INEEL with this sample for particle analysis. The sample was collected by vacuuming a section of the machine (covering approximately 1/3 of the machine surface) with a coarse fiber filter as the collection surface. The sample was then analyzed using an optical microscope, SEM microscope, Microtrac FRA particle size analyzer. The data fit a log-normal distribution. The count median diameter (CMD) of the samples ranged from 0.3 microm to 1.1 microm with geometric standard deviations (GSD) ranging from 2.8 to 5.2 and a mass median diameter (MMD) ranging from 7.22 to 176 microm

  18. Computational modeling of particle transport and distribution emitted from a Laserjet printer in a ventilated room with different ventilation configurations

    International Nuclear Information System (INIS)

    Ansaripour, Mehrzad; Abdolzadeh, Morteza; Sargazizadeh, Saleh

    2016-01-01

    Highlights: • The distribution of emitted particles form a laserjet printer was studied in the breathing zone. • Effects of different ventilation configurations on the breathing zone concentration were investigated. • Mixing ventilation system has a low mean particle concentration in the breathing zone. - Abstract: In the present research, computational modeling of particle transport and distribution emitted from a Laserjet printer was carried out in a ventilated room. A seated manikin was integrated into the study room and the manikin was evaluated in two cases: heated and unheated. Effects of different ventilation configurations of the room on the particle distribution were studied, including three displacement ventilation systems and a mixing ventilation system. The printer was located on different sides of the manikin and the particle concentrations in the breathing zone of the manikin due to the printer’s particles were evaluated in all the ventilation configurations. The averaged particle concentration in the breathing zone of the manikin was calculated and validated with the experimental and numerical data available in the literature. The results of the present study showed that in case of the heated manikin, the particle concentration due to the printer pollutants is significant in the breathing zone of the manikin. The results also showed that when the printer is located on the front side of the manikin, the particle concentration in the breathing zone is quite high in most of the used ventilation configurations. Furthermore, it was found that the mixing ventilation system has a lower mean particle concentration in the breathing zone compared to the most displacement ventilation systems.

  19. Incidence and distribution of leek yellow stripe virus in allium crops in Serbia

    Directory of Open Access Journals (Sweden)

    Vučurović Ivan

    2017-01-01

    Full Text Available Leek yellow stripe virus (LYSV is one of the most frequent and important viruses in leek and garlic crops worldwide. In Serbia this virus is found both in leek and garlic, and often at high percentages. During two consecutive years, 2012 and 2013, a total 92 samples were collected from 11 inspected leek-, garlic- and onion-growing locations and they were analyzed for the presence of LYSV using DAS-ELISA. LYSV was detected in 31.5% of the tested samples. In 2012, the presence of LYSV was only detected in leek plants, and in 55.6% of the tested samples. During 2013, LYSV was detected in 85% of leek and 58.3% of garlic samples. In total, LYSV was detected in 56.4% of leek samples and 17.1% garlic samples. LYSV incidence was confirmed using RT-PCR with LYSV specific primers amplifying 1020 bp fragment representing coat protein and part of nuclear inclusion B genes. Molecular identification was confirmed by sequencing of two selected isolates, 181-13 (MG242625 from garlic and 298-13 (MG242624 from leek, and comparing them to the GenBank sequences of LYSV. Phylogenetic analysis of 55 sequences of LYSV from all over the world showed some correlation between host plant and geographical origin of the isolates, forming five separate clades. Two Serbian LYSV isolates fell into distant clades. The Serbian leek isolate 298-13 of LYSV belongs to clade B, while isolate 181-13 originating from garlic belongs in clade E.

  20. Siting and sizing of distributed generators based on improved simulated annealing particle swarm optimization.

    Science.gov (United States)

    Su, Hongsheng

    2017-12-18

    Distributed power grids generally contain multiple diverse types of distributed generators (DGs). Traditional particle swarm optimization (PSO) and simulated annealing PSO (SA-PSO) algorithms have some deficiencies in site selection and capacity determination of DGs, such as slow convergence speed and easily falling into local trap. In this paper, an improved SA-PSO (ISA-PSO) algorithm is proposed by introducing crossover and mutation operators of genetic algorithm (GA) into SA-PSO, so that the capabilities of the algorithm are well embodied in global searching and local exploration. In addition, diverse types of DGs are made equivalent to four types of nodes in flow calculation by the backward or forward sweep method, and reactive power sharing principles and allocation theory are applied to determine initial reactive power value and execute subsequent correction, thus providing the algorithm a better start to speed up the convergence. Finally, a mathematical model of the minimum economic cost is established for the siting and sizing of DGs under the location and capacity uncertainties of each single DG. Its objective function considers investment and operation cost of DGs, grid loss cost, annual purchase electricity cost, and environmental pollution cost, and the constraints include power flow, bus voltage, conductor current, and DG capacity. Through applications in an IEEE33-node distributed system, it is found that the proposed method can achieve desirable economic efficiency and safer voltage level relative to traditional PSO and SA-PSO algorithms, and is a more effective planning method for the siting and sizing of DGs in distributed power grids.

  1. Rumen Contents and Ruminal Digesta Particle Size Distribution in Buffalo Steers Fed Three Different Size of Alfalfa

    Directory of Open Access Journals (Sweden)

    A. Teimouri Yansari

    2010-02-01

    Full Text Available This study was conducted to investigate the effects of three sizes of alfalfa and time post-feeding on rumen contents and on particle size distribution of ruminal digesta. Three ruminally fistulated buffalo steers received a diet consisting just alfalfa that was harvested at 15% of flowering and chopped in three sizes. Individual small rectangular bales were chopped with a forage field harvester for theoretical cut length 19 and 10 mm for preparation of long and medium particle size, also the fine particles were prepared by milling. The geometric means and its standard deviation were 8.5, 5.5 and 2.5 mm; and 1.24, 1.16 and 1.06 mm, in coarse, medium and fine, respectively. The experimental design was a repeated 3×3 Latin squares with 21 day periods. The diets were offered twice daily at 09:00 and 21:00 h at ad libitum level. The rumens were evacuated manually at 3, 7.5 and 12h post-feeding and total ruminal contents separated into mat and bailable liquids. Dry matter weight distribution of total recovered particles was determined by a wet-sieving procedure and used to partition ruminal mat and bailable liquids among percentages of large (≥4.0 mm, medium (<4.0mm and ≥1.18 mm, and fine (<1.18 mm and ≥0.05 mm particles. Intake did not influence markedly the distribution of different particle fractions, whereas particle size and time post-feeding had a pronounced effect. With increasing time after feeding, percentage of large and medium particles significantly decreased, whereas the percentage of fine particles significantly increased. The ruminal digesta particle distributions illustrated intensive particle breakdown in the reticulo-rumen for coarse particle more than others. Dry matter contents and the proportion of particulate dry matter in the rumen increased as intake increased, i.e. ruminal mat increased at the expense of bailable liquids. It can be concluded that reduction of forage particle size for buffaloes at maintenance level

  2. Study on the Particle Size Distribution Nano-Particles of Mining Minerals on Whiteness of Triaxial Body

    Science.gov (United States)

    Mathur, Ravi; Soni, Aditi

    White wares produced worldwide represent the foundation of much of the ceramic industry; Porcelain bodies fabricated from triaxial mixtures of clay, quartz and feldspar with different size and amounts of nano particles were investigated. Although the purity of raw materials has a strong effect on the colour of the fired bodies, the particle size of raw materials also effect the whiteness The raw material mining minerals china Clay, Feldspar, quarts were prepared of various sized nano particles contains 10.60 -20.22%, 56.84- 70.80 % and 34.87-50.76 % of 100nm respectively. The fired bodies of raw mining minerals and triaxial bodies were subjected to colour measurement. The differences in whiteness were compared and discussed. The studies so far carried out is upto 400 mesh size while the present study has included up to 100nm particle size. A statistical correlation between whiteness of feldspar and triaxial body was also carried out. The correlation between china clay and triaxial body are 0.53, 0.57 and 0.66 for china clay similarly correlation for feldspar is 0.49, 0.73 and 0.83 for triaxial body it are 0.97, 0.84 and 0.75 for A1, A2 and A3 samples. Correlation between china clay and feldspar with triaxial body are 0.79 and 0.92 respectively.

  3. Intercomparison of 15 Aerodynamic Particle Size Spectrometers (APS 3321): Uncertainties in Particle Sizing and Number Size Distribution.

    Czech Academy of Sciences Publication Activity Database

    Pfeifer, S.; Müller, T.; Weinhold, K.; Zíková, Naděžda; dos Santos, S.M.; Marinoni, A.; Bischof, O.F.; Kykal, C.; Ries, L.; Meinhardt, F.; Aalto, P.; Mihalopoulos, N.; Wiedensohler, A.

    2016-01-01

    Roč. 9, č. 4 (2016), s. 1545-1551 ISSN 1867-1381 EU Projects: European Commission(XE) 262254 - ACTRIS Institutional support: RVO:67985858 Keywords : counting efficiency * aerodynamic particle size spectrometers * laboratory study Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.089, year: 2016

  4. The effect of sawtooth oscillations on the alpha particle distribution and energy balance in the ITER plasma

    Science.gov (United States)

    Zaitsev, F. S.; Gorelenkov, N. N.; Petrov, M. P.; Afanasyev, V. I.; Mironov, M. I.

    2017-11-01

    The mixing of toroidal plasma under the conditions of sawtooth oscillations is considered using the Kadomtsev model. A new mixing formula for the averaged distribution function of fast transit and trapped particles is proposed in the methodology of a kinetic equation averaged over drift trajectories. The proposed formula generalizes the known results for the case of non-circular magnetic surfaces, an arbitrary aspect ratio, and charged particle drift trajectories significantly deviating from the magnetic surfaces. The formula is applicable for a sufficiently wide class of instabilities. The 3D kinetic equation is numerically solved using the FPP- 3D computation code for parameters close to the ITER inductive scenario. The alpha particle distribution function and the power introduced by alpha particles in plasma when sawtooth oscillations occur are calculated. It is shown that such oscillations may change the energy input of a thermonuclear reaction in certain areas by several times.

  5. Impact of screw configuration on the particle size distribution of granules produced by twin screw granulation.

    Science.gov (United States)

    Vercruysse, J; Burggraeve, A; Fonteyne, M; Cappuyns, P; Delaet, U; Van Assche, I; De Beer, T; Remon, J P; Vervaet, C

    2015-02-01

    Twin screw granulation (TSG) has been reported by different research groups as an attractive technology for continuous wet granulation. However, in contrast to fluidized bed granulation, granules produced via this technique typically have a wide and multimodal particle size distribution (PSD), resulting in suboptimal flow properties. The aim of the current study was to evaluate the impact of granulator screw configuration on the PSD of granules produced by TSG. Experiments were performed using a 25 mm co-rotating twin screw granulator, being part of the ConsiGma™-25 system (a fully continuous from-powder-to-tablet manufacturing line from GEA Pharma Systems). Besides the screw elements conventionally used for TSG (conveying and kneading elements), alternative designs of screw elements (tooth-mixing-elements (TME), screw mixing elements (SME) and cutters) were investigated using an α-lactose monohydrate formulation granulated with distilled water. Granulation with only conveying elements resulted in wide and multimodal PSD. Using kneading elements, the width of the PSD could be partially narrowed and the liquid distribution was more homogeneous. However, still a significant fraction of oversized agglomerates was obtained. Implementing additional kneading elements or cutters in the final section of the screw configuration was not beneficial. Furthermore, granulation with only TME or SME had limited impact on the width of the PSD. Promising results were obtained by combining kneading elements with SME, as for these configurations the PSD was narrower and shifted to the size fractions suitable for tableting. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Modeling blowing snow accumulation downwind of an obstruction: The Ohara Eulerian particle distribution equation

    Science.gov (United States)

    Kinar, N. J.

    2017-05-01

    An equation was proposed to model the height of blowing snow accumulation downwind of an obstacle such as vegetation, a snow fence, a building, or a topographic feature. The equation does not require aerodynamic flow condition parameters such as wind speed, allowing for the spatial distribution of snow to be determined at locations where meteorological data is not available. However, snow particle diffusion, drift, and erosion coefficients must be estimated for application of the equation. These coefficients can be used to provide insight into the relative magnitude of blowing snow processes at a field location. Further research is required to determine efficient methods for coefficient estimation. The equation could be used with other models of wind-transported snow to predict snow accumulation downwind of an obstacle without the need for wind speed adjustments or correction equations. Applications for this equation include the design of snow fences, and the use of this equation with other hydrological models to predict snow distribution, climate change, drought, flooding, and avalanches.

  7. Influence of the Sieving Amplitude on the Particle Size Distribution of Corn Flour for Direct Expanded Extrudates Manufacturing

    OpenAIRE

    Valentina Obradović; Mladen Brnčić; Damir Ježek

    2009-01-01

    The object of the sieving process is to separate a mixture of a granulated material into fractions. Each fraction contains particles of similar dimensions. The primary object of this research was to determine how the change of sieving amplitude affects the particle size distribution and definition of optimal fraction for processing of direct expanded extrudates based on corn fl our. Sieving analysis was done by”Analisette 3“shaker, model Pro sieve opening sizes were 355, 315, 250, 200, 160, 1...

  8. Aerosol particle mixing state, refractory particle number size distributions and emission factors in a polluted urban environment: Case study of Metro Manila, Philippines

    Science.gov (United States)

    Kecorius, Simonas; Madueño, Leizel; Vallar, Edgar; Alas, Honey; Betito, Grace; Birmili, Wolfram; Cambaliza, Maria Obiminda; Catipay, Grethyl; Gonzaga-Cayetano, Mylene; Galvez, Maria Cecilia; Lorenzo, Genie; Müller, Thomas; Simpas, James B.; Tamayo, Everlyn Gayle; Wiedensohler, Alfred

    2017-12-01

    Ultrafine soot particles (black carbon, BC) in urban environments are related to adverse respiratory and cardiovascular effects, increased cases of asthma and premature deaths. These problems are especially pronounced in developing megacities in South-East Asia, Latin America, and Africa, where unsustainable urbanization ant outdated environmental protection legislation resulted in severe degradation of urban air quality in terms of black carbon emission. Since ultrafine soot particles do often not lead to enhanced PM10 and PM2.5 mass concentration, the risks related to ultrafine particle pollution may therefore be significantly underestimated compared to the contribution of secondary aerosol constituents. To increase the awareness of the potential toxicological relevant problems of ultrafine black carbon particles, we conducted a case study in Metro Manila, the capital of the Philippines. Here, we present a part of the results from a detailed field campaign, called Manila Aerosol Characterization Experiment (MACE, 2015). Measurements took place from May to June 2015 with the focus on the state of mixing of aerosol particles. The results were alarming, showing the abundance of externally mixed refractory particles (soot proxy) at street site with a maximum daily number concentration of approximately 15000 #/cm3. That is up to 10 times higher than in cities of Western countries. We also found that the soot particle mass contributed from 55 to 75% of total street site PM2.5. The retrieved refractory particle number size distribution appeared to be a superposition of 2 ultrafine modes at 20 and 80 nm with a corresponding contribution to the total refractory particle number of 45 and 55%, respectively. The particles in the 20 nm mode were most likely ash from metallic additives in lubricating oil, tiny carbonaceous particles and/or nucleated and oxidized organic polymers, while bigger ones (80 nm) were soot agglomerates. To the best of the authors' knowledge, no other

  9. Understanding the uneven distribution of the incidence of homicide in Latin America.

    Science.gov (United States)

    Briceño-León, Roberto; Villaveces, Andrés; Concha-Eastman, Alberto

    2008-08-01

    Throughout the final years of the twentieth century and into the beginning of the twenty-first, violence has been one of the main public health issues in Latin America, a region which has some of the highest mortality rates due to violence in the world. However, there seems to be an uneven geographical distribution of such instances. We reviewed epidemiological data on violence globally and in Latin America, and here, we discuss differences between the Latin American countries in the context of a sociological framework as well as from a public health perspective. Our results indicate marked differences by country in terms of rates of violence. Countries such as Argentina, Chile, Costa Rica, and Uruguay, have low violence mortality rates; Peru, Nicaragua, Ecuador, Dominican Republic, Panama, and Paraguay have moderate rates, and Brazil, Mexico, Colombia, El Salvador, Honduras and Venezuela have high to extremely high mortality rates. Factors related to violence include social inequalities, lack of employment opportunities, urban segregation, a culture of masculinity, local drug markets, and the availability of firearms and widespread use of alcohol. The observed homicide variability between Latin American countries can be explained largely by differences in the countries' social contexts and political models. In those countries where homicide rates are extremely high, governments should review their current policies and take preventive actions. Fortunately increasingly nowadays there are promising advancements in that direction.

  10. Inspection of 56Fe γ-Ray angular distributions as a function of incident neutron energy using optical model approaches

    Directory of Open Access Journals (Sweden)

    Vanhoy J.R.

    2017-01-01

    Full Text Available Neutron inelastic scattering cross sections measured directly through (n,n or deduced from γ-ray production cross sections following inelastic neutron scattering (n,n′γ are a focus of basic and applied research at the University of Kentucky Accelerator Laboratory (www.pa.uky.edu/accelerator. For nuclear data applications, angle-integrated cross sections are desired over a wide range of fast neutron energies. Several days of experimental beam time are required for a data set at each incident neutron energy, which limits the number of angular distributions that can be measured in a reasonable amount of time. Approximations can be employed to generate cross sections with a higher energy resolution, since at 125o, the a2P2 term of the Legendre expansion is identically zero and the a4P4 is assumed to be very small. Provided this assumption is true, a single measurement at 125o would produce the γ-ray production cross section. This project tests these assumptions and energy dependences using the codes CINDY/SCAT and TALYS/ECIS06/SCAT. It is found that care must be taken when interpreting γ-ray excitation functions as cross sections when the incident neutron energy is < 1000 keV above threshold or before the onset of feeding.

  11. Inspection of 56Fe γ-Ray angular distributions as a function of incident neutron energy using optical model approaches

    Science.gov (United States)

    Vanhoy, J. R.; Ramirez, A. P.; Alcorn-Dominguez, D. K.; Hicks, S. F.; Peters, E. E.; McEllistrem, M. T.; Mukhopadhyay, S.; Yates, S. W.

    2017-09-01

    Neutron inelastic scattering cross sections measured directly through (n,n) or deduced from γ-ray production cross sections following inelastic neutron scattering (n,n'γ) are a focus of basic and applied research at the University of Kentucky Accelerator Laboratory (www.pa.uky.edu/accelerator). For nuclear data applications, angle-integrated cross sections are desired over a wide range of fast neutron energies. Several days of experimental beam time are required for a data set at each incident neutron energy, which limits the number of angular distributions that can be measured in a reasonable amount of time. Approximations can be employed to generate cross sections with a higher energy resolution, since at 125o, the a2P2 term of the Legendre expansion is identically zero and the a4P4 is assumed to be very small. Provided this assumption is true, a single measurement at 125o would produce the γ-ray production cross section. This project tests these assumptions and energy dependences using the codes CINDY/SCAT and TALYS/ECIS06/SCAT. It is found that care must be taken when interpreting γ-ray excitation functions as cross sections when the incident neutron energy is < 1000 keV above threshold or before the onset of feeding.

  12. Particle-size dependence on metal(loid) distributions in mine wastes: Implications for water contamination and human exposure

    Science.gov (United States)

    Kim, C.S.; Wilson, K.M.; Rytuba, J.J.

    2011-01-01

    The mining and processing of metal-bearing ores has resulted in contamination issues where waste materials from abandoned mines remain in piles of untreated and unconsolidated material, posing the potential for waterborne and airborne transport of toxic elements. This study presents a systematic method of particle size separation, mass distribution, and bulk chemical analysis for mine tailings and adjacent background soil samples from the Rand historic mining district, California, in order to assess particle size distribution and related trends in metal(loid) concentration as a function of particle size. Mine tailings produced through stamp milling and leaching processes were found to have both a narrower and finer particle size distribution than background samples, with significant fractions of particles available in a size range (???250 ??m) that could be incidentally ingested. In both tailings and background samples, the majority of trace metal(loid)s display an inverse relationship between concentration and particle size, resulting in higher proportions of As, Cr, Cu, Pb and Zn in finer-sized fractions which are more susceptible to both water- and wind-borne transport as well as ingestion and/or inhalation. Established regulatory screening levels for such elements may, therefore, significantly underestimate potential exposure risk if relying solely on bulk sample concentrations to guide remediation decisions. Correlations in elemental concentration trends (such as between As and Fe) indicate relationships between elements that may be relevant to their chemical speciation. ?? 2011 Elsevier Ltd.

  13. Aerosol and NOx emission factors and submicron particle number size distributions in two road tunnels with different traffic regimes

    Directory of Open Access Journals (Sweden)

    D. Imhof

    2006-01-01

    Full Text Available Measurements of aerosol particle number size distributions (18–700 nm, mass concentrations (PM2.5 and PM10 and NOx were performed in the Plabutsch tunnel, Austria, and in the Kingsway tunnel, United Kingdom. These two tunnels show different characteristics regarding the roadway gradient, the composition of the vehicle fleet and the traffic frequency. The submicron particle size distributions contained a soot mode in the diameter range D=80–100 nm and a nucleation mode in the range of D=20–40 nm. In the Kingsway tunnel with a significantly lower particle number and volume concentration level than in the Plabutsch tunnel, a clear diurnal variation of nucleation and soot mode particles correlated to the traffic density was observed. In the Plabutsch tunnel, soot mode particles also revealed a diurnal variation, whereas no substantial variation was found for the nucleation mode particles. During the night a higher number concentration of nucleation mode particles were measured than soot mode particles and vice versa during the day. In this tunnel with very high soot emissions during daytime due to the heavy-duty vehicle (HDV share of 18% and another 40% of diesel driven light-duty vehicles (LDV semivolatile species condense on the pre-existing soot surface area rather than forming new particles by homogeneous nucleation. With the low concentration of soot mode particles in the Kingsway tunnel, also the nucleation mode particles exhibit a diurnal variation. From the measured parameters real-world traffic emission factors were estimated for the whole vehicle fleet as well as differentiated into the two categories LDV and HDV. In the particle size range D=18–700 nm, each vehicle of the mixed fleet emits (1.50±0.08×1014 particles km-1 (Plabutsch and (1.26±0.10×1014 particles km-1 (Kingsway, while particle volume emission factors of 0.209±0.008 cm3 km-1 and 0.036±0.004 cm3 km-1, respectively, were obtained. PM1 emission factors of 104±4 mg

  14. Spatial distribution and potential sources of trace metals in insoluble particles of snow from Urumqi, China.

    Science.gov (United States)

    Li, Xiaolan; Jiang, Fengqing; Wang, Shaoping; Turdi, Muyesser; Zhang, Zhaoyong

    2015-01-01

    The purpose of this work is to characterize trace elements in snow in urban-suburb gradient over Urumqi city, China. The spatial distribution patterns of 11 trace metals in insoluble particulate matters of snow were revealed by using 102 snow samples collected in and around urban areas of Urumqi, a city suffering from severe wintertime air pollution in China. Similar spatial distribution for Mn, Cu, Zn, Ni, and Pb was found and their two significant high-value areas located in the west and east, respectively, and a high-value area in the south, which were correlated with factory emissions, traffic activities, and construction fugitive dust. The high-value areas of Cr, Ni, and V occurred in the northeast corner and along main traffic paths, which were linked to oil refinery and vehicular emissions. High value of Be presented in the west of the city. The high-value area of Co in the northeast could be related to local soil. Cd and U displayed relatively even spatial patterns in the urban area. In view of distance from the urban center, e.g., from the first circular belt to the fourth circular belt, except Be, V, Cd, and U, the contents of other metals generally decreased from the first circular belt to the forth circular belt, implying the effect of human activity clearly. Additionally, prevailing northwesterly winds and occasionally southeasterly winds in winter were associated with decreased, generally, concentrations of trace metal in snow from the urban center to the southern suburb along a northwest and southeast transect. The information on concentrations and spatial distributions of these metals in insoluble particles of snow in winter will be valuable for further environmental protection and planning.

  15. Comparison of particle-size distributions determined by optical scanning and by sieving in the assessment of masticatory performance.

    Science.gov (United States)

    Eberhard, L; Schindler, H J; Hellmann, D; Schmitter, M; Rammelsberg, P; Giannakopoulos, N N

    2012-05-01

    Aim of this study was to introduce a feasible and valid technique for the assessment of masticatory performance that is comparable to the standard sieving method. Twenty-one chewing samples (Optosil) comminuted by healthy dentate adults were analysed with a sieving and scanning method. Scanning was performed using a conventional flatbed scanner (1200dpi). All scanned images underwent image analysis (ImageJ), which yielded descriptive parameters such as area, best-fitting ellipse for each particle. Of the 2D-image, a volume was estimated for each particle, which was converted into a weight. To receive a discrete distribution of particle sizes comparable to sieving, five chewing samples were used to calculate a size-dependent area-volume-conversion factor. The sieving procedure was carried out with a stack of 10 sieves, and the retained particles per sieve were weighed. The cumulated weights yielded by either method were curve-fitted with the Rosin-Rammler distribution to determine the median particle size x(50) . The Rosin-Rammler distributions for sieving and scanning resemble each other. The distributions show a high correlation (0·919-1·0, n= 21, Psieving. On average, scanning overestimates the x(50) values by 2·4%. A modified Bland-Altman plot reveals that 95% of the x(50) values fall within 10% of the average x(50) . The scanning method is a valid, simple and feasible method to determine masticatory performance. © 2012 Blackwell Publishing Ltd.

  16. Risks of nuclear waste disposal in space. III - Long-term orbital evolution of small particle distribution

    Science.gov (United States)

    Friedlander, A. L.; Wells, W. C.

    1980-01-01

    A study of long term risks is presented that treats an additional pathway that could result in earth reentry, namely, small radioactive particles released in solar orbit due to payload fragmentation by accidental explosion or meteoroid impact. A characterization of such an event and of the initial mass size distribution of particles is given for two extremes of waste form strength. Attention is given to numerical results showing the mass-time distribution of material and the fraction of initial mass intercepted by earth. It is concluded that it appears that program planners need not be to concerned about the risks of this particular failure mechanism and return pathway.

  17. The Asymptotic Behavior of Particle Size Distribution Undergoing Brownian Coagulation Based on the Spline-Based Method and TEMOM Model

    Directory of Open Access Journals (Sweden)

    Qing He

    2018-01-01

    Full Text Available In this paper, the particle size distribution is reconstructed using finite moments based on a converted spline-based method, in which the number of linear system of equations to be solved reduced from 4m × 4m to (m + 3 × (m + 3 for (m + 1 nodes by using cubic spline compared to the original method. The results are verified by comparing with the reference firstly. Then coupling with the Taylor-series expansion moment method, the evolution of particle size distribution undergoing Brownian coagulation and its asymptotic behavior are investigated.

  18. Generation of initial kinetic distributions for simulation of long-pulse charged particle beams with high space-charge intensity

    Directory of Open Access Journals (Sweden)

    Steven M. Lund

    2009-11-01

    Full Text Available Self-consistent Vlasov-Poisson simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel—both in terms of low-order rms (envelope properties as well as the higher-order phase-space structure. Here, we first review broad classes of kinetic distributions commonly in use as initial Vlasov distributions in simulations of unbunched or weakly bunched beams with intense space-charge fields including the following: the Kapchinskij-Vladimirskij (KV equilibrium, continuous-focusing equilibria with specific detailed examples, and various nonequilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of standard accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial kinetic distributions are constructed using transformations that preserve linear focusing, single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for noncontinuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulations that more precisely probe intrinsic stability properties and machine performance.

  19. Generation of Initial Kinetic Distributions for Simulation of Long-Pulse Charged Particle Beams with High Space-Charge intensity

    Energy Technology Data Exchange (ETDEWEB)

    Lund, Steven M.; Kikuchi, Takashi; Davidson, Ronald C.

    2007-04-03

    Self-consistent Vlasov-Poisson simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel--both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of kinetic distributions commonly in use as initial Vlasov distributions in simulations of unbunched or weakly bunched beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial kinetic distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

  20. Generation of initial Vlasov distributions for simulation of charged particle beams with high space-charge intensity

    Energy Technology Data Exchange (ETDEWEB)

    Lund, S M; Kikuchi, T; Davidson, R C

    2007-04-12

    Self-consistent Vlasov simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel, both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of distributions commonly in use as initial Vlasov distributions in simulations of beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

  1. Modeling the Hydrological Cycle in the Atmosphere of Mars: Influence of a Bimodal Size Distribution of Aerosol Nucleation Particles

    Science.gov (United States)

    Shaposhnikov, Dmitry S.; Rodin, Alexander V.; Medvedev, Alexander S.; Fedorova, Anna A.; Kuroda, Takeshi; Hartogh, Paul

    2018-02-01

    We present a new implementation of the hydrological cycle scheme into a general circulation model of the Martian atmosphere. The model includes a semi-Lagrangian transport scheme for water vapor and ice and accounts for microphysics of phase transitions between them. The hydrological scheme includes processes of saturation, nucleation, particle growth, sublimation, and sedimentation under the assumption of a variable size distribution. The scheme has been implemented into the Max Planck Institute Martian general circulation model and tested assuming monomodal and bimodal lognormal distributions of ice condensation nuclei. We present a comparison of the simulated annual variations, horizontal and vertical distributions of water vapor, and ice clouds with the available observations from instruments on board Mars orbiters. The accounting for bimodality of aerosol particle distribution improves the simulations of the annual hydrological cycle, including predicted ice clouds mass, opacity, number density, and particle radii. The increased number density and lower nucleation rates bring the simulated cloud opacities closer to observations. Simulations show a weak effect of the excess of small aerosol particles on the simulated water vapor distributions.

  2. Estimation of aerosol particle number distributions with Kalman Filtering – Part 1: Theory, general aspects and statistical validity

    Directory of Open Access Journals (Sweden)

    T. Viskari

    2012-12-01

    Full Text Available Aerosol characteristics can be measured with different instruments providing observations that are not trivially inter-comparable. Extended Kalman Filter (EKF is introduced here as a method to estimate aerosol particle number size distributions from multiple simultaneous observations. The focus here in Part 1 of the work was on general aspects of EKF in the context of Differential Mobility Particle Sizer (DMPS measurements. Additional instruments and their implementations are discussed in Part 2 of the work. University of Helsinki Multi-component Aerosol model (UHMA is used to propagate the size distribution in time. At each observation time (10 min apart, the time evolved state is updated with the raw particle mobility distributions, measured with two DMPS systems. EKF approach was validated by calculating the bias and the standard deviation for the estimated size distributions with respect to the raw measurements. These were compared to corresponding bias and standard deviation values for particle number size distributions obtained from raw measurements by a inversion of the instrument kernel matrix method. Despite the assumptions made in the EKF implementation, EKF was found to be more accurate than the inversion of the instrument kernel matrix in terms of bias, and compatible in terms of standard deviation. Potential further improvements of the EKF implementation are discussed.

  3. Green method for producing hierarchically assembled pristine porous ZnO nanoparticles with narrow particle size distribution

    International Nuclear Information System (INIS)

    Escobedo-Morales, A.; Téllez-Flores, D.; Ruiz Peralta, Ma. de Lourdes; Garcia-Serrano, J.; Herrera-González, Ana M.; Rubio-Rosas, E.; Sánchez-Mora, E.; Olivares Xometl, O.

    2015-01-01

    A green method for producing pristine porous ZnO nanoparticles with narrow particle size distribution is reported. This method consists in synthesizing ZnO 2 nanopowders via a hydrothermal route using cheap and non-toxic reagents, and its subsequent thermal decomposition at low temperature under a non-protective atmosphere (air). The morphology, structural and optical properties of the obtained porous ZnO nanoparticles were studied by means of powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and nitrogen adsorption–desorption measurements. It was found that after thermal decomposition of the ZnO 2 powders, pristine ZnO nanoparticles are obtained. These particles are round-shaped with narrow size distribution. A further analysis of the obtained ZnO nanoparticles reveals that they are hierarchical self-assemblies of primary ZnO particles. The agglomeration of these primary particles at the very early stage of the thermal decomposition of ZnO 2 powders provides to the resulting ZnO nanoparticles a porous nature. The possibility of using the synthesized porous ZnO nanoparticles as photocatalysts has been evaluated on the degradation of rhodamine B dye. - Highlights: • A green synthesis method for obtaining porous ZnO nanoparticles is reported. • The obtained ZnO nanoparticles have narrow particle size distribution. • This method allows obtaining pristine ZnO nanoparticles avoiding unintentional doping. • A growth mechanism for the obtained porous ZnO nanoparticles is proposed

  4. Correlating capacity and Li content in layered material for Li-ion battery using XRD and particle size distribution measurements

    Science.gov (United States)

    Al-Tabbakh, A. A. A.; Al-Zubaidi, A. B.; Kamarulzaman, N.

    2016-03-01

    A lithiated transition-metal oxide material was successfully synthesized by a combustion method for Li-ion battery. The material was characterized using thermogravimetric and particle size analyzers, scanning electron microscope and X-ray diffractometer. The calcined powders of the material exhibited a finite size distribution and a single phase of pure layered structure of space group Roverline{3} m . An innovative method was developed to calculate the material electrochemical capacity based on considerations of the crystal structure and contributions of Li ions from specified unit cells at the surfaces and in the interiors of the material particles. Results suggested that most of the Li ions contributing to the electrochemical current originated from the surface region of the material particles. It was possible to estimate the thickness of the most delithiated region near the particle surfaces at any delithiation depth accurately. Furthermore, results suggested that the core region of the particles remained electrochemically inaccessible in the conventional applied voltages. This result was justified by direct quantitative comparison of specific capacity values calculated from the particle size distribution with those measured experimentally. The present analysis is believed to be of some value for estimation of the failure mechanism in cathode compounds, thus assisting the development of Li-ion batteries.

  5. Screen-Space Normal Distribution Function Caching for Consistent Multi-Resolution Rendering of Large Particle Data

    KAUST Repository

    Ibrahim, Mohamed

    2017-08-28

    Molecular dynamics (MD) simulations are crucial to investigating important processes in physics and thermodynamics. The simulated atoms are usually visualized as hard spheres with Phong shading, where individual particles and their local density can be perceived well in close-up views. However, for large-scale simulations with 10 million particles or more, the visualization of large fields-of-view usually suffers from strong aliasing artifacts, because the mismatch between data size and output resolution leads to severe under-sampling of the geometry. Excessive super-sampling can alleviate this problem, but is prohibitively expensive. This paper presents a novel visualization method for large-scale particle data that addresses aliasing while enabling interactive high-quality rendering. We introduce the novel concept of screen-space normal distribution functions (S-NDFs) for particle data. S-NDFs represent the distribution of surface normals that map to a given pixel in screen space, which enables high-quality re-lighting without re-rendering particles. In order to facilitate interactive zooming, we cache S-NDFs in a screen-space mipmap (S-MIP). Together, these two concepts enable interactive, scale-consistent re-lighting and shading changes, as well as zooming, without having to re-sample the particle data. We show how our method facilitates the interactive exploration of real-world large-scale MD simulation data in different scenarios.

  6. Wideband converter of a charge of particle beam incident on a Faraday cylinder into a number of pulses

    International Nuclear Information System (INIS)

    Shchagin, A.V.; Lysenko, V.F.

    1985-01-01

    An electric circuit of a beam positive charge-pulse converter during beam incidence on a Faraday cylinder (conversion of Faraday cylinder current into F frequency, where F=10 10 J, where J - is the Faraday cylinder current) is described. Conversion ratio is 10 10 pulses/KP (10 10 Hz/A). Input current change limits are 10 -10 -10 -4 A. Conversion error is |ΔF| -3 F +0.1 Hz). ''Dead'' time is absent. Input resistance of the converter is close to zero

  7. Distribution of Trauma Care Facilities in Oman in Relation to High-Incidence Road Traffic Injury Sites: Pilot study

    Directory of Open Access Journals (Sweden)

    Sara M. Al-Kindi

    2018-01-01

    Full Text Available Objectives: Road traffic injuries (RTIs are considered a major public health problem worldwide. In Oman, high numbers of RTIs and RTI-related deaths are frequently registered. This study aimed to evaluate the distribution of trauma care facilities in Oman with regards to their proximity to RTI-prevalent areas. Methods: This descriptive pilot study analysed RTI data recorded in the national Royal Oman Police registry from January to December 2014. The distribution of trauma care facilities was analysed by calculating distances between areas of peak RTI incidence and the closest trauma centre using Google Earth and Google Maps software (Google Inc., Googleplex, Mountain View, California, USA. Results: A total of 32 trauma care facilities were identified. Four facilities (12.5% were categorised as class V trauma centres. Of the facilities in Muscat, 42.9% were ranked as class IV or V. There were no class IV or V facilities in Musandam, Al-Wusta or Al-Buraimi. General surgery, orthopaedic surgery and neurosurgery services were available in 68.8%, 59.3% and 12.5% of the centres, respectively. Emergency services were available in 75.0% of the facilities. Intensive care units were available in 11 facilities, with four located in Muscat. The mean distance between a RTI hotspot and the nearest trauma care facility was 34.7 km; however, the mean distance to the nearest class IV or V facility was 83.3 km. Conclusion: The distribution and quality of trauma care facilities in Oman needs modification. It is recommended that certain centres upgrade their levels of trauma care in order to reduce RTI-associated morbidity and mortality in Oman.

  8. Theory of nonlinear interaction of particles and waves in an inverse plasma maser. Part 2; Stationary solution and evolution of initial distributions

    Energy Technology Data Exchange (ETDEWEB)

    Krivitsky, V.S.; Vladimirov, S.V. (Academy of Sciences of the USSR, Moscow (USSR). General Physics Institute. Theoretical Dept.)

    1991-10-01

    The evolution of the distribution function due to the simultaneous nonlinear interaction of plasma particles with resonant and non-resonant waves is studied. A stationary particle distribution resulting from a balance of the quasi-linear interaction and the nonlinear one is found. The temporal evolution of an initial {delta}-function-shaped distribution (like a 'beam') is examined in the one-dimensional case. General formulae are obtained for stochastic particle acceleration. (author).

  9. PCE and BNS admixture adsorption in sands with different composition and particle size distribution

    Directory of Open Access Journals (Sweden)

    M. M. Alonso

    2017-02-01

    Full Text Available The choice of a superplasticiser (SP for concrete is of great complexity, as it is well known that properties of the end product are related to admixture and its compatibility with concrete components. Very few studies have been conducted on the compatibility between SPs and the sand of mortars and concretes, however. Practical experience has shown that sand fineness and mineralogical composition affect water demand and admixture consumption. Clay-containing sand has been found also to adsorb SPs, reducing the amount available in solution for adsorption by the cement. This study analysed the isotherms for PCE and BNS superplasticiser adsorption on four sands with different fineness and compositions commonly used to prepare mortars and concretes. BNS-based SP did not adsorb on sands, while PCE-based admixtures exhibited variable adsorption depending on different factors. The adsorption curves obtained revealed that the higher the sand fineness, the finer the particle size distribution and the higher the clay material, the greater was PCE admixture adsorption/ consumption.

  10. Fractal Scaling of Particle Size Distribution and Relationships with Topsoil Properties Affected by Biological Soil Crusts

    Science.gov (United States)

    Gao, Guang-Lei; Ding, Guo-Dong; Wu, Bin; Zhang, Yu-Qing; Qin, Shu-Gao; Zhao, Yuan-Yuan; Bao, Yan-Feng; Liu, Yun-Dong; Wan, Li; Deng, Ji-Feng

    2014-01-01

    Background Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions. Methodology/Principal Findings To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of successional biological soil crusts (algae, lichens, and mosses crust), as well as the referenced sandland in the Mu Us Desert, Northern China. Relationships between fractal dimensions of soil particle size distribution and selected soil properties were discussed as well. The results indicated that biological soil crusts had significant positive effects on soil physical structure (Psoil organic carbon and nutrients showed an upward trend across the successional stages of biological soil crusts. Fractal dimensions ranged from 2.1477 to 2.3032, and significantly linear correlated with selected soil properties (R2 = 0.494∼0.955, Psoil crusts cause an important increase in soil fertility, and are beneficial to sand fixation, although the process is rather slow. Fractal dimension proves to be a sensitive and useful index for quantifying changes in soil properties that additionally implies desertification. This study will be essential to provide a firm basis for future policy-making on optimal solutions regarding desertification control and assessment, as well as degraded ecosystem restoration in arid and semiarid regions. PMID:24516668

  11. PCE and BNS admixture adsorption in sands with different composition and particle size distribution

    International Nuclear Information System (INIS)

    Alonso, M.M.; Martínez-Gaitero, R.; Gismera-Diez, S.; Puertas, F.

    2017-01-01

    The choice of a superplasticiser (SP) for concrete is of great complexity, as it is well known that properties of the end product are related to admixture and its compatibility with concrete components. Very few studies have been conducted on the compatibility between SPs and the sand of mortars and concretes, however. Practical experience has shown that sand fineness and mineralogical composition affect water demand and admixture consumption. Clay-containing sand has been found also to adsorb SPs, reducing the amount available in solution for adsorption by the cement. This study analysed the isotherms for PCE and BNS superplasticiser adsorption on four sands with different fineness and compositions commonly used to prepare mortars and concretes. BNS-based SP did not adsorb on sands, while PCE-based admixtures exhibited variable adsorption depending on different factors. The adsorption curves obtained revealed that the higher the sand fineness, the finer the particle size distribution and the higher the clay material, the greater was PCE admixture adsorption/ consumption. [es

  12. The effect of particle size distribution on the design of urban stormwater control measures

    Science.gov (United States)

    Selbig, William R.; Fienen, Michael N.; Horwatich, Judy A.; Bannerman, Roger T.

    2016-01-01

    An urban pollutant loading model was used to demonstrate how incorrect assumptions on the particle size distribution (PSD) in urban runoff can alter the design characteristics of stormwater control measures (SCMs) used to remove solids in stormwater. Field-measured PSD, although highly variable, is generally coarser than the widely-accepted PSD characterized by the Nationwide Urban Runoff Program (NURP). PSDs can be predicted based on environmental surrogate data. There were no appreciable differences in predicted PSD when grouped by season. Model simulations of a wet detention pond and catch basin showed a much smaller surface area is needed to achieve the same level of solids removal using the median value of field-measured PSD as compared to NURP PSD. Therefore, SCMs that used the NURP PSD in the design process could be unnecessarily oversized. The median of measured PSDs, although more site-specific than NURP PSDs, could still misrepresent the efficiency of an SCM because it may not adequately capture the variability of individual runoff events. Future pollutant loading models may account for this variability through regression with environmental surrogates, but until then, without proper site characterization, the adoption of a single PSD to represent all runoff conditions may result in SCMs that are under- or over-sized, rendering them ineffective or unnecessarily costly.

  13. Fractal scaling of particle size distribution and relationships with topsoil properties affected by biological soil crusts.

    Directory of Open Access Journals (Sweden)

    Guang-Lei Gao

    Full Text Available BACKGROUND: Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions. METHODOLOGY/PRINCIPAL FINDINGS: To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of successional biological soil crusts (algae, lichens, and mosses crust, as well as the referenced sandland in the Mu Us Desert, Northern China. Relationships between fractal dimensions of soil particle size distribution and selected soil properties were discussed as well. The results indicated that biological soil crusts had significant positive effects on soil physical structure (P<0.05; and soil organic carbon and nutrients showed an upward trend across the successional stages of biological soil crusts. Fractal dimensions ranged from 2.1477 to 2.3032, and significantly linear correlated with selected soil properties (R(2 = 0.494∼0.955, P<0.01. CONCLUSIONS/SIGNIFICANCE: Biological soil crusts cause an important increase in soil fertility, and are beneficial to sand fixation, although the process is rather slow. Fractal dimension proves to be a sensitive and useful index for quantifying changes in soil properties that additionally implies desertification. This study will be essential to provide a firm basis for future policy-making on optimal solutions regarding desertification control and assessment, as well as degraded ecosystem restoration in arid and semiarid regions.

  14. Global distribution of particle phase state in atmospheric secondary organic aerosols.

    Science.gov (United States)

    Shiraiwa, Manabu; Li, Ying; Tsimpidi, Alexandra P; Karydis, Vlassis A; Berkemeier, Thomas; Pandis, Spyros N; Lelieveld, Jos; Koop, Thomas; Pöschl, Ulrich

    2017-04-21

    Secondary organic aerosols (SOA) are a large source of uncertainty in our current understanding of climate change and air pollution. The phase state of SOA is important for quantifying their effects on climate and air quality, but its global distribution is poorly characterized. We developed a method to estimate glass transition temperatures based on the molar mass and molecular O:C ratio of SOA components, and we used the global chemistry climate model EMAC with the organic aerosol module ORACLE to predict the phase state of atmospheric SOA. For the planetary boundary layer, global simulations indicate that SOA are mostly liquid in tropical and polar air with high relative humidity, semi-solid in the mid-latitudes and solid over dry lands. We find that in the middle and upper troposphere SOA should be mostly in a glassy solid phase state. Thus, slow diffusion of water, oxidants and organic molecules could kinetically limit gas-particle interactions of SOA in the free and upper troposphere, promote ice nucleation and facilitate long-range transport of reactive and toxic organic pollutants embedded in SOA.

  15. Relationship between Particle Size Distribution of Low-Rank Pulverized Coal and Power Plant Performance

    Directory of Open Access Journals (Sweden)

    Rajive Ganguli

    2012-01-01

    Full Text Available The impact of particle size distribution (PSD of pulverized, low rank high volatile content Alaska coal on combustion related power plant performance was studied in a series of field scale tests. Performance was gauged through efficiency (ratio of megawatt generated to energy consumed as coal, emissions (SO2, NOx, CO, and carbon content of ash (fly ash and bottom ash. The study revealed that the tested coal could be burned at a grind as coarse as 50% passing 76 microns, with no deleterious impact on power generation and emissions. The PSD’s tested in this study were in the range of 41 to 81 percent passing 76 microns. There was negligible correlation between PSD and the followings factors: efficiency, SO2, NOx, and CO. Additionally, two tests where stack mercury (Hg data was collected, did not demonstrate any real difference in Hg emissions with PSD. The results from the field tests positively impacts pulverized coal power plants that burn low rank high volatile content coals (such as Powder River Basin coal. These plants can potentially reduce in-plant load by grinding the coal less (without impacting plant performance on emissions and efficiency and thereby, increasing their marketability.

  16. Effect of truncation of electron velocity distribution on release of dust particle from plasma-facing wall

    International Nuclear Information System (INIS)

    Tomita, Y.; Smirnov, R.; Nakamura, H.; Zhu, S.; Takizuka, T.; Tskhakaya, D.

    2007-01-01

    In modeling of release of a dust particle from a plasma-facing wall it is usually assumed that electron velocity distribution is Maxwellian. However, the absorption of fast electrons by the conducting wall can lead to truncation of fast component of reflecting electrons from the wall. In this work we study the effect of truncation of electron velocity distribution on the release condition of a conducting spherical dust particle from the plasma-facing wall. The truncation increases the electric field at the wall surface compared to that calculated in absence of the truncation. The stronger electric field makes the dust particle hard released when the gravitational force is directed from the wall and applied wall potential is shallower than the floating one

  17. Particle size distribution and column efficiency. An ongoing debate revived with 1.9μm Titan-C18 particles.

    Science.gov (United States)

    Gritti, Fabrice; Bell, David S; Guiochon, Georges

    2014-08-15

    The mass transfer mechanism in four prototype columns (2.1 and 3.0×50mm, 2.1 and 3.0×100mm) packed with 1.9μm fully porous Titan-C18 particles was investigated by using two previously reported home-made protocols. The first one was used to measure the eddy dispersion HETP of these new columns, the second one to estimate their intrinsic (corrected for HPLC system contribution) HETPs. Titan particles are fully porous particles with a narrow particle size distribution (RSD of 9.2%). The mean Sauter diameter (dSauter=2.04μm) was determined from Coulter counter measurements on the raw silica material (before C18 derivatization) and in the absence of a dispersant agent (Triton X-100) in a 2% NaCl electrolyte solution. The results show that these RPLC Titan columns have intrinsic minimum reduced HETPs ranging from 1.7 to 1.9 and generate up to 290,000 plates per meter. The 3.0mm i.d. columns are more efficient than the 2.1mm i.d. ones and short columns are preferred to minimize efficiency losses due to frictional heating at high speeds. This work also revealed that (1) the lowest h values of the Titan columns are observed at low reduced velocities (νopt=5); (2) this is due to the unusually small diffusivity of analytes across the porous Titan-C18 particles; and (3) the Titan columns are not packed more uniformly than conventional columns packed with fully porous particles. Earlier and recent findings showing that the PSD has no direct physical impact on eddy dispersion and column efficiency are confirmed by these results. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Incidence and distribution of Botrytis convoluta in a collection of Iris × barbata irises and options of control

    Directory of Open Access Journals (Sweden)

    Ivana Šafránková

    2009-01-01

    Full Text Available In the years 2005–2007 in a collection of Iris × barbata irises in the Botanical Garden and Arboretum of MZLU in Brno a disease spread appearing in symptoms of poor budding and growth of the irises, or rotting and dying off of the rhizomes. As the causal agent we identified the fungus Botrytis convoluta. In the present study we describe the isolated pathogen. The disease appears in a number of species of the genus Iris and has been reported in the USA, Europe, Israel and Japan. Over a period of three years we evaluated the frequency of incidence of the pathogen in 527 iris cultivars and its distribution on five plots. While in the first year the incidence of the pathogen appeared in 4.4–28.7 % plants, in the last year of our investigations the pathogen spread to 17.7–66.6 % plants. In the course of three years seven cultivars out of the 527 planted out died as a result of B. convoluta attack (i.e. 1.33 %. The results were processed statistically. Spacing of the plants and gradient of the plot influenced the spreading of the pathogen. The weather in the winter played an important role, particularly mild and humid winters with temperatures above 0 °C. Even though B. convoluta was and remains to be a factor limiting the overwintering of irises, there are very few data on fungicide control of irises. Even fewer data are available about the control of irises against latently infected rhizomes. At the present time no fungicides protecting irises against this pathogen have been registered in the Czech Republic.

  19. Comparison of Particle-Associated Bacteria from a Drinking Water Treatment Plant and Distribution Reservoirs with Different Water Sources

    Science.gov (United States)

    Liu, G.; Ling, F. Q.; van der Mark, E. J.; Zhang, X. D.; Knezev, A.; Verberk, J. Q. J. C.; van der Meer, W. G. J.; Medema, G. J.; Liu, W. T.; van Dijk, J. C.

    2016-01-01

    This study assessed the characteristics of and changes in the suspended particles and the associated bacteria in an unchlorinated drinking water distribution system and its reservoirs with different water sources. The results show that particle-associated bacteria (PAB) were present at a level of 0.8–4.5 × 103 cells ml−1 with a biological activity of 0.01–0.04 ng l−1 ATP. Different PAB communities in the waters produced from different sources were revealed by a 16S rRNA-based pyrosequencing analysis. The quantified biomass underestimation due to the multiple cells attached per particle was ≥ 85%. The distribution of the biologically stable water increased the number of cells per particle (from 48 to 90) but had minor effects on the PAB community. Significant changes were observed at the mixing reservoir. Our results show the characteristics of and changes in suspended PAB during distribution, and highlight the significance of suspended PAB in the distribution system, because suspended PAB can lead to a considerable underestimation of biomass, and because they exist as biofilm, which has a greater mobility than pipe-wall biofilm and therefore presents a greater risk, given the higher probability that it will reach the customers’ taps and be ingested. PMID:26832989

  20. Fractal Features of Soil Particle Size Distribution Under Different Plant Communities in the Forested Region of Mountain Yimeng, China

    Science.gov (United States)

    In order to explore the effect of changes in plant communities and land use on soil properties, as a result of anthropogenic disturbances, we apply the theory of fractals and soil physics as a means to better quantify changes in particle-size distribution (PSD) and soil porosity. Fractal dimension a...

  1. Influence of Cement Particle-Size Distribution on Early Age Autogenous Strains and Stresses in Cement-Based Materials

    DEFF Research Database (Denmark)

    Bentz, Dale P.; Jensen, Ole Mejlhede; Hansen, Kurt Kielsgaard

    2001-01-01

    The influence of cement particle-size distribution on autogenous strains and stresses in cement pastes of identical water-to-cement ratios is examined for cement powders of four different finenesses. Experimental measurements include chemical shrinkage, to quantify degree of hydration; internal r...

  2. Comparison of Particle-Associated Bacteria from a Drinking Water Treatment Plant and Distribution Reservoirs with Different Water Sources.

    Science.gov (United States)

    Liu, G; Ling, F Q; van der Mark, E J; Zhang, X D; Knezev, A; Verberk, J Q J C; van der Meer, W G J; Medema, G J; Liu, W T; van Dijk, J C

    2016-02-02

    This study assessed the characteristics of and changes in the suspended particles and the associated bacteria in an unchlorinated drinking water distribution system and its reservoirs with different water sources. The results show that particle-associated bacteria (PAB) were present at a level of 0.8-4.5 × 10(3) cells ml(-1) with a biological activity of 0.01-0.04 ng l(-1) ATP. Different PAB communities in the waters produced from different sources were revealed by a 16S rRNA-based pyrosequencing analysis. The quantified biomass underestimation due to the multiple cells attached per particle was ≥ 85%. The distribution of the biologically stable water increased the number of cells per particle (from 48 to 90) but had minor effects on the PAB community. Significant changes were observed at the mixing reservoir. Our results show the characteristics of and changes in suspended PAB during distribution, and highlight the significance of suspended PAB in the distribution system, because suspended PAB can lead to a considerable underestimation of biomass, and because they exist as biofilm, which has a greater mobility than pipe-wall biofilm and therefore presents a greater risk, given the higher probability that it will reach the customers' taps and be ingested.

  3. Neutron and alpha particle energy spectrum and angular distribution effects from beam--plasma D-T fusion

    International Nuclear Information System (INIS)

    Lessor, D.L.

    1975-04-01

    The following five topics are discussed: (1) origin of energy spread in fusion neutrons, (2) magnitude of neutron energy spread from beam--plasma fusions, (3) techniques for calculation of fusion product particle spectra, (4) neutron spectra from fusion in isotropic plasmas, and (5) calculation of fusion neutron energy and angle distributions. (U.S.)

  4. Effects of diet composition and ultrasound treatment on particle size distribution and carbon bioavailability in feces of rainbow trout

    NARCIS (Netherlands)

    Meriac, A.; Tilburg, van T.; Eding, E.H.; Kamstra, A.; Schrama, J.W.; Verreth, J.A.J.

    2015-01-01

    The effect of a high and low non-starch polysaccharide diet (HNSP and LNSP diet) and ultrasound treatment on particle size distribution and carbon bioavailability in fecal waste of rainbow trout (Oncorynchus mykiss) was studied. Feces were collected from four flow-through fish tanks, two tanks fed

  5. Particle size distribution and perchlorate levels in settled dust from urban roads, parks, and roofs in Chengdu, China.

    Science.gov (United States)

    Li, Yiwen; Shen, Yang; Pi, Lu; Hu, Wenli; Chen, Mengqin; Luo, Yan; Li, Zhi; Su, Shijun; Ding, Sanglan; Gan, Zhiwei

    2016-01-01

    A total of 27 settled dust samples were collected from urban roads, parks, and roofs in Chengdu, China to investigate particle size distribution and perchlorate levels in different size fractions. Briefly, fine particle size fractions (dust samples, with mean percentages of 80.2%, 69.5%, and 77.2% for the urban roads, roofs, and the parks, respectively. Perchlorate was detected in all of the size-fractionated dust samples, with concentrations ranging from 73.0 to 6160 ng g(-1), and the median perchlorate levels increased with decreasing particle size. The perchlorate level in the finest fraction (dust intake is safe to both children and adults in Chengdu, China. However, due to perchlorate mainly existing in fine particles, there is a potential for perchlorate to transfer into surface water and the atmosphere by runoff and wind erosion or traffic emission, and this could act as an important perchlorate pollution source for the indoor environment, and merits further study.

  6. Forward-backward correlations and charged-particle azimuthal distributions in $pp$ interactions using the ATLAS detector

    CERN Document Server

    Aad, Georges; Abdallah, Jalal; Abdelalim, Ahmed Ali; Abdesselam, Abdelouahab; Abdinov, Ovsat; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Acerbi, Emilio; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Aderholz, Michael; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Akiyama, Kunihiro; Alam, Mohammad; Alam, Muhammad Aftab; Albert, Justin; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Aliyev, Magsud; Allbrooke, Benedict; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amaral, Pedro; Amelung, Christoph; Ammosov, Vladimir; Amorim, Antonio; Amorós, Gabriel; Amram, Nir; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Andrieux, Marie-Laure; Anduaga, Xabier; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Asfandiyarov, Ruslan; Ask, Stefan; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Astvatsatourov, Anatoli; Aubert, Bernard; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Ay, Cano; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barashkou, Andrei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beale, Steven; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Begel, Michael; Behar Harpaz, Silvia; Behera, Prafulla; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellina, Francesco; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Ben Ami, Sagi; Benary, Odette; Benchekroun, Driss; Benchouk, Chafik; Bendel, Markus; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertinelli, Francesco; Bertolucci, Federico; Besana, Maria Ilaria; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Biscarat, Catherine; Bitenc, Urban; Black, Kevin; Blair, Robert; Blanchard, Jean-Baptiste; Blanchot, Georges; Blazek, Tomas; Blocker, Craig; Blocki, Jacek; Blondel, Alain; Blum, Walter; Blumenschein, Ulrike; Bobbink, Gerjan; Bobrovnikov, Victor; Bocchetta, Simona Serena; Bocci, Andrea; Boddy, Christopher Richard; Boehler, Michael; Boek, Jennifer; Boelaert, Nele; Bogaerts, Joannes Andreas; Bogdanchikov, Alexander; Bogouch, Andrei; Bohm, Christian; Boisvert, Veronique; Bold, Tomasz; Boldea, Venera; Bolnet, Nayanka Myriam; Bona, Marcella; Bondarenko, Valery; Bondioli, Mario; Boonekamp, Maarten; Booth, Chris; Bordoni, Stefania; Borer, Claudia; Borisov, Anatoly; Borissov, Guennadi; Borjanovic, Iris; Borri, Marcello; Borroni, Sara; Bortolotto, Valerio; Bos, Kors; Boscherini, Davide; Bosman, Martine; Boterenbrood, Hendrik; Botterill, David; Bouchami, Jihene; Boudreau, Joseph; Bouhova-Thacker, Evelina Vassileva; Boumediene, Djamel Eddine; Bourdarios, Claire; Bousson, Nicolas; Boveia, Antonio; Boyd, James; Boyko, Igor; Bozhko, Nikolay; Bozovic-Jelisavcic, Ivanka; Bracinik, Juraj; Braem, André; Branchini, Paolo; Brandenburg, George; Brandt, Andrew; Brandt, Gerhard; Brandt, Oleg; Bratzler, Uwe; Brau, Benjamin; Brau, James; Braun, Helmut; Brelier, Bertrand; Bremer, Johan; Brenner, Richard; Bressler, Shikma; Britton, Dave; Brochu, Frederic; Brock, Ian; Brock, Raymond; Brodbeck, Timothy; Brodet, Eyal; Broggi, Francesco; Bromberg, Carl; Bronner, Johanna; Brooijmans, Gustaaf; Brooks, William; Brown, Gareth; Brown, Heather; Bruckman de Renstrom, Pawel; Bruncko, Dusan; Bruneliere, Renaud; Brunet, Sylvie; Bruni, Alessia; Bruni, Graziano; Bruschi, Marco; Buanes, Trygve; Buat, Quentin; Bucci, Francesca; Buchanan, James; Buchanan, Norman; Buchholz, Peter; Buckingham, Ryan; Buckley, Andrew; Buda, Stelian Ioan; Budagov, Ioulian; Budick, Burton; Büscher, Volker; Bugge, Lars; Bulekov, Oleg; Bunse, Moritz; Buran, Torleiv; Burckhart, Helfried; Burdin, Sergey; Burgess, Thomas; Burke, Stephen; Busato, Emmanuel; Bussey, Peter; Buszello, Claus-Peter; Butin, François; Butler, Bart; Butler, John; Buttar, Craig; Butterworth, Jonathan; Buttinger, William; Cabrera Urbán, Susana; Caforio, Davide; Cakir, Orhan; Calafiura, Paolo; Calderini, Giovanni; Calfayan, Philippe; Calkins, Robert; Caloba, Luiz; Caloi, Rita; Calvet, David; Calvet, Samuel; Camacho Toro, Reina; Camarri, Paolo; Cambiaghi, Mario; Cameron, David; Caminada, Lea Michaela; Campana, Simone; Campanelli, Mario; Canale, Vincenzo; Canelli, Florencia; Canepa, Anadi; Cantero, Josu; Capasso, Luciano; Capeans Garrido, Maria Del Mar; Caprini, Irinel; Caprini, Mihai; Capriotti, Daniele; Capua, Marcella; Caputo, Regina; Caramarcu, Costin; Cardarelli, Roberto; Carli, Tancredi; Carlino, Gianpaolo; Carminati, Leonardo; Caron, Bryan; Caron, Sascha; Carrillo Montoya, German D; Carter, Antony; Carter, Janet; Carvalho, João; Casadei, Diego; Casado, Maria Pilar; Cascella, Michele; Caso, Carlo; Castaneda Hernandez, Alfredo Martin; Castaneda-Miranda, Elizabeth; Castillo Gimenez, Victoria; Castro, Nuno Filipe; Cataldi, Gabriella; Cataneo, Fernando; Catinaccio, Andrea; Catmore, James; Cattai, Ariella; Cattani, Giordano; Caughron, Seth; Cauz, Diego; Cavalleri, Pietro; Cavalli, Donatella; Cavalli-Sforza, Matteo; Cavasinni, Vincenzo; Ceradini, Filippo; Santiago Cerqueira, Augusto; Cerri, Alessandro; Cerrito, Lucio; Cerutti, Fabio; Cetin, Serkant Ali; Cevenini, Francesco; Chafaq, Aziz; Chakraborty, Dhiman; Chan, Kevin; Chapleau, Bertrand; Chapman, John Derek; Chapman, John Wehrley; Chareyre, Eve; Charlton, Dave; Chavda, Vikash; Chavez Barajas, Carlos Alberto; Cheatham, Susan; Chekanov, Sergei; Chekulaev, Sergey; Chelkov, Gueorgui; Chelstowska, Magda Anna; Chen, Chunhui; Chen, Hucheng; Chen, Shenjian; Chen, Tingyang; Chen, Xin; Cheng, Shaochen; Cheplakov, Alexander; Chepurnov, Vladimir; Cherkaoui El Moursli, Rajaa; Chernyatin, Valeriy; Cheu, Elliott; Cheung, Sing-Leung; Chevalier, Laurent; Chiefari, Giovanni; Chikovani, Leila; Childers, John Taylor; Chilingarov, Alexandre; Chiodini, Gabriele; Chisholm, Andrew; Chizhov, Mihail; Choudalakis, Georgios; Chouridou, Sofia; Christidi, Illectra-Athanasia; Christov, Asen; Chromek-Burckhart, Doris; Chu, Ming-Lee; Chudoba, Jiri; Ciapetti, Guido; Ciba, Krzysztof; Ciftci, Abbas Kenan; Ciftci, Rena; Cinca, Diane; Cindro, Vladimir; Ciobotaru, Matei Dan; Ciocca, Claudia; Ciocio, Alessandra; Cirilli, Manuela; Citterio, Mauro; Ciubancan, Mihai; Clark, Allan G; Clark, Philip James; Cleland, Bill; Clemens, Jean-Claude; Clement, Benoit; Clement, Christophe; Clifft, Roger; Coadou, Yann; Cobal, Marina; Coccaro, Andrea; Cochran, James H; Coe, Paul; Cogan, Joshua Godfrey; Coggeshall, James; Cogneras, Eric; Colas, Jacques; Colijn, Auke-Pieter; Collins, Neil; Collins-Tooth, Christopher; Collot, Johann; Colon, German; Conde Muiño, Patricia; Coniavitis, Elias; Conidi, Maria Chiara; Consonni, Michele; Consorti, Valerio; Constantinescu, Serban; Conta, Claudio; Conventi, Francesco; Cook, James; Cooke, Mark; Cooper, Ben; Cooper-Sarkar, Amanda; Copic, Katherine; Cornelissen, Thijs; Corradi, Massimo; Corriveau, Francois; Cortes-Gonzalez, Arely; Cortiana, Giorgio; Costa, Giuseppe; Costa, María José; Costanzo, Davide; Costin, Tudor; Côté, David; Coura Torres, Rodrigo; Courneyea, Lorraine; Cowan, Glen; Cowden, Christopher; Cox, Brian; Cranmer, Kyle; Crescioli, Francesco; Cristinziani, Markus; Crosetti, Giovanni; Crupi, Roberto; Crépé-Renaudin, Sabine; Cuciuc, Constantin-Mihai; Cuenca Almenar, Cristóbal; Cuhadar Donszelmann, Tulay; Curatolo, Maria; Curtis, Chris; Cuthbert, Cameron; Cwetanski, Peter; Czirr, Hendrik; Czodrowski, Patrick; Czyczula, Zofia; D'Auria, Saverio; D'Onofrio, Monica; D'Orazio, Alessia; Da Silva, Paulo Vitor; Da Via, Cinzia; Dabrowski, Wladyslaw; Dai, Tiesheng; Dallapiccola, Carlo; Dam, Mogens; Dameri, Mauro; Damiani, Daniel; Danielsson, Hans Olof; Dannheim, Dominik; Dao, Valerio; Darbo, Giovanni; Darlea, Georgiana Lavinia; Davey, Will; Davidek, Tomas; Davidson, Nadia; Davidson, Ruth; Davies, Eleanor; Davies, Merlin; Davison, Adam; Davygora, Yuriy; Dawe, Edmund; Dawson, Ian; Dawson, John; Daya-Ishmukhametova, Rozmin; De, Kaushik; de Asmundis, Riccardo; De Castro, Stefano; De Castro Faria Salgado, Pedro; De Cecco, Sandro; de Graat, Julien; De Groot, Nicolo; de Jong, Paul; De La Taille, Christophe; De la Torre, Hector; De Lotto, Barbara; de Mora, Lee; De Nooij, Lucie; De Pedis, Daniele; De Salvo, Alessandro; De Sanctis, Umberto; De Santo, Antonella; De Vivie De Regie, Jean-Baptiste; Dean, Simon; Dearnaley, William James; Debbe, Ramiro; Debenedetti, Chiara; Dedovich, Dmitri; Degenhardt, James; Dehchar, Mohamed; Del Papa, Carlo; Del Peso, Jose; Del Prete, Tarcisio; Delemontex, Thomas; Deliyergiyev, Maksym; Dell'Acqua, Andrea; Dell'Asta, Lidia; Della Pietra, Massimo; della Volpe, Domenico; Delmastro, Marco; Delruelle, Nicolas; Delsart, Pierre-Antoine; Deluca, Carolina; Demers, Sarah; Demichev, Mikhail; Demirkoz, Bilge; Deng, Jianrong; Denisov, Sergey; Derendarz, Dominik; Derkaoui, Jamal Eddine; Derue, Frederic; Dervan, Paul; Desch, Klaus Kurt; Devetak, Erik; Deviveiros, Pier-Olivier; Dewhurst, Alastair; DeWilde, Burton; Dhaliwal, Saminder; Dhullipudi, Ramasudhakar; Di Ciaccio, Anna; Di Ciaccio, Lucia; Di Girolamo, Alessandro; Di Girolamo, Beniamino; Di Luise, Silvestro; Di Mattia, Alessandro; Di Micco, Biagio; Di Nardo, Roberto; Di Simone, Andrea; Di Sipio, Riccardo; Diaz, Marco Aurelio; Diblen, Faruk; Diehl, Edward; Dietrich, Janet; Dietzsch, Thorsten; Diglio, Sara; Dindar Yagci, Kamile; Dingfelder, Jochen; Dionisi, Carlo; Dita, Petre; Dita, Sanda; Dittus, Fridolin; Djama, Fares; Djobava, Tamar; Barros do Vale, Maria Aline; Do Valle Wemans, André; Doan, Thi Kieu Oanh; Dobbs, Matt; Dobinson, Robert; Dobos, Daniel; Dobson, Ellie; Dodd, Jeremy; Doglioni, Caterina; Doherty, Tom; Doi, Yoshikuni; Dolejsi, Jiri; Dolenc, Irena; Dolezal, Zdenek; Dolgoshein, Boris; Dohmae, Takeshi; Donadelli, Marisilvia; Donega, Mauro; Donini, Julien; Dopke, Jens; Doria, Alessandra; Dos Anjos, Andre; Dosil, Mireia; Dotti, Andrea; Dova, Maria-Teresa; Dowell, John; Doxiadis, Alexander; Doyle, Tony; Drasal, Zbynek; Drees, Jürgen; Dressnandt, Nandor; Drevermann, Hans; Driouichi, Chafik; Dris, Manolis; Dubbert, Jörg; Dube, Sourabh; Duchovni, Ehud; Duckeck, Guenter; Dudarev, Alexey; Dudziak, Fanny; Dührssen, Michael; Duerdoth, Ian; Duflot, Laurent; Dufour, Marc-Andre; Dunford, Monica; Duran Yildiz, Hatice; Duxfield, Robert; Dwuznik, Michal; Dydak, Friedrich; Düren, Michael; Ebenstein, William; Ebke, Johannes; Eckweiler, Sebastian; Edmonds, Keith; Edwards, Clive; Edwards, Nicholas Charles; Ehrenfeld, Wolfgang; Ehrich, Thies; Eifert, Till; Eigen, Gerald; Einsweiler, Kevin; Eisenhandler, Eric; Ekelof, Tord; El Kacimi, Mohamed; Ellert, Mattias; Elles, Sabine; Ellinghaus, Frank; Ellis, Katherine; Ellis, Nicolas; Elmsheuser, Johannes; Elsing, Markus; Emeliyanov, Dmitry; Engelmann, Roderich; Engl, Albert; Epp, Brigitte; Eppig, Andrew; Erdmann, Johannes; Ereditato, Antonio; Eriksson, Daniel; Ernst, Jesse; Ernst, Michael; Ernwein, Jean; Errede, Deborah; Errede, Steven; Ertel, Eugen; Escalier, Marc; Escobar, Carlos; Espinal Curull, Xavier; Esposito, Bellisario; Etienne, Francois; Etienvre, Anne-Isabelle; Etzion, Erez; Evangelakou, Despoina; Evans, Hal; Fabbri, Laura; Fabre, Caroline; Fakhrutdinov, Rinat; Falciano, Speranza; Fang, Yaquan; Fanti, Marcello; Farbin, Amir; Farilla, Addolorata; Farley, Jason; Farooque, Trisha; Farrington, Sinead; Farthouat, Philippe; Fassnacht, Patrick; Fassouliotis, Dimitrios; Fatholahzadeh, Baharak; Favareto, Andrea; Fayard, Louis; Fazio, Salvatore; Febbraro, Renato; Federic, Pavol; Fedin, Oleg; Fedorko, Woiciech; Fehling-Kaschek, Mirjam; Feligioni, Lorenzo; Fellmann, Denis; Feng, Cunfeng; Feng, Eric; Fenyuk, Alexander; Ferencei, Jozef; Ferland, Jonathan; Fernando, Waruna; Ferrag, Samir; Ferrando, James; Ferrara, Valentina; Ferrari, Arnaud; Ferrari, Pamela; Ferrari, Roberto; Ferreira de Lima, Danilo Enoque; Ferrer, Antonio; Ferrer, Maria Lorenza; Ferrere, Didier; Ferretti, Claudio; Ferretto Parodi, Andrea; Fiascaris, Maria; Fiedler, Frank; Filipčič, Andrej; Filippas, Anastasios; Filthaut, Frank; Fincke-Keeler, Margret; Fiolhais, Miguel; Fiorini, Luca; Firan, Ana; Fischer, Gordon; Fischer, Peter; Fisher, Matthew; Flechl, Martin; Fleck, Ivor; Fleckner, Johanna; Fleischmann, Philipp; Fleischmann, Sebastian; Flick, Tobias; Floderus, Anders; Flores Castillo, Luis; Flowerdew, Michael; Fokitis, Manolis; Fonseca Martin, Teresa; Forbush, David Alan; Formica, Andrea; Forti, Alessandra; Fortin, Dominique; Foster, Joe; Fournier, Daniel; Foussat, Arnaud; Fowler, Andrew; Fowler, Ken; Fox, Harald; Francavilla, Paolo; Franchino, Silvia; Francis, David; Frank, Tal; Franklin, Melissa; Franz, Sebastien; Fraternali, Marco; Fratina, Sasa; French, Sky; Friedrich, Felix; Froeschl, Robert; Froidevaux, Daniel; Frost, James; Fukunaga, Chikara; Fullana Torregrosa, Esteban; Fuster, Juan; Gabaldon, Carolina; Gabizon, Ofir; Gadfort, Thomas; Gadomski, Szymon; Gagliardi, Guido; Gagnon, Pauline; Galea, Cristina; Gallas, Elizabeth; Gallo, Valentina Santina; Gallop, Bruce; Gallus, Petr; Gan, KK; Gao, Yongsheng; Gapienko, Vladimir; Gaponenko, Andrei; Garberson, Ford; Garcia-Sciveres, Maurice; García, Carmen; García Navarro, José Enrique; Gardner, Robert; Garelli, Nicoletta; Garitaonandia, Hegoi; Garonne, Vincent; Garvey, John; Gatti, Claudio; Gaudio, Gabriella; Gaur, Bakul; Gauthier, Lea; Gavrilenko, Igor; Gay, Colin; Gaycken, Goetz; Gayde, Jean-Christophe; Gazis, Evangelos; Ge, Peng; Gee, Norman; Geerts, Daniël Alphonsus Adrianus; Geich-Gimbel, Christoph; Gellerstedt, Karl; Gemme, Claudia; Gemmell, Alistair; Genest, Marie-Hélène; Gentile, Simonetta; George, Matthias; George, Simon; Gerlach, Peter; Gershon, Avi; Geweniger, Christoph; Ghazlane, Hamid; Ghodbane, Nabil; Giacobbe, Benedetto; Giagu, Stefano; Giakoumopoulou, Victoria; Giangiobbe, Vincent; Gianotti, Fabiola; Gibbard, Bruce; Gibson, Adam; Gibson, Stephen; Gilbert, Laura; Gilewsky, Valentin; Gillberg, Dag; Gillman, Tony; Gingrich, Douglas; Ginzburg, Jonatan; Giokaris, Nikos; Giordani, MarioPaolo; Giordano, Raffaele; Giorgi, Francesco Michelangelo; Giovannini, Paola; Giraud, Pierre-Francois; Giugni, Danilo; Giunta, Michele; Giusti, Paolo; Gjelsten, Børge Kile; Gladilin, Leonid; Glasman, Claudia; Glatzer, Julian; Glazov, Alexandre; Glitza, Karl-Walter; Glonti, George; Goddard, Jack Robert; Godfrey, Jennifer; Godlewski, Jan; Goebel, Martin; Göpfert, Thomas; Goeringer, Christian; Gössling, Claus; Göttfert, Tobias; Goldfarb, Steven; Golling, Tobias; Gomes, Agostinho; Gomez Fajardo, Luz Stella; Gonçalo, Ricardo; Goncalves Pinto Firmino Da Costa, Joao; Gonella, Laura; Gonidec, Allain; Gonzalez, Saul; González de la Hoz, Santiago; Gonzalez Parra, Garoe; Gonzalez Silva, Laura; Gonzalez-Sevilla, Sergio; Goodson, Jeremiah Jet; Goossens, Luc; Gorbounov, Petr Andreevich; Gordon, Howard; Gorelov, Igor; Gorfine, Grant; Gorini, Benedetto; Gorini, Edoardo; Gorišek, Andrej; Gornicki, Edward; Gorokhov, Serguei; Goryachev, Vladimir; Gosdzik, Bjoern; Gosselink, Martijn; Gostkin, Mikhail Ivanovitch; Gough Eschrich, Ivo; Gouighri, Mohamed; Goujdami, Driss; Goulette, Marc Phillippe; Goussiou, Anna; Goy, Corinne; Gozpinar, Serdar; Grabowska-Bold, Iwona; Grafström, Per; Grahn, Karl-Johan; Grancagnolo, Francesco; Grancagnolo, Sergio; Grassi, Valerio; Gratchev, Vadim; Grau, Nathan; Gray, Heather; Gray, Julia Ann; Graziani, Enrico; Grebenyuk, Oleg; Greenshaw, Timothy; Greenwood, Zeno Dixon; Gregersen, Kristian; Gregor, Ingrid-Maria; Grenier, Philippe; Griffiths, Justin; Grigalashvili, Nugzar; Grillo, Alexander; Grinstein, Sebastian; Grishkevich, Yaroslav; Grivaz, Jean-Francois; Groh, Manfred; Gross, Eilam; Grosse-Knetter, Joern; Groth-Jensen, Jacob; Grybel, Kai; Guarino, Victor; Guest, Daniel; Guicheney, Christophe; Guida, Angelo; Guindon, Stefan; Guler, Hulya; Gunther, Jaroslav; Guo, Bin; Guo, Jun; Gupta, Ambreesh; Gusakov, Yury; Gushchin, Vladimir; Gutierrez, Phillip; Guttman, Nir; Gutzwiller, Olivier; Guyot, Claude; Gwenlan, Claire; Gwilliam, Carl; Haas, Andy; Haas, Stefan; Haber, Carl; Hadavand, Haleh Khani; Hadley, David; Haefner, Petra; Hahn, Ferdinand; Haider, Stefan; Hajduk, Zbigniew; Hakobyan, Hrachya; Hall, David; Haller, Johannes; Hamacher, Klaus; Hamal, Petr; Hamer, Matthias; Hamilton, Andrew; Hamilton, Samuel; Han, Hongguang; Han, Liang; Hanagaki, Kazunori; Hanawa, Keita; Hance, Michael; Handel, Carsten; Hanke, Paul; Hansen, John Renner; Hansen, Jørgen Beck; Hansen, Jorn Dines; Hansen, Peter Henrik; Hansson, Per; Hara, Kazuhiko; Hare, Gabriel; Harenberg, Torsten; Harkusha, Siarhei; Harper, Devin; Harrington, Robert; Harris, Orin; Harrison, Karl; Hartert, Jochen; Hartjes, Fred; Haruyama, Tomiyoshi; Harvey, Alex; Hasegawa, Satoshi; Hasegawa, Yoji; Hassani, Samira; Hatch, Mark; Hauff, Dieter; Haug, Sigve; Hauschild, Michael; Hauser, Reiner; Havranek, Miroslav; Hawes, Brian; Hawkes, Christopher; Hawkings, Richard John; Hawkins, Anthony David; Hawkins, Donovan; Hayakawa, Takashi; Hayashi, Takayasu; Hayden, Daniel; Hayward, Helen; Haywood, Stephen; Hazen, Eric; He, Mao; Head, Simon; Hedberg, Vincent; Heelan, Louise; Heim, Sarah; Heinemann, Beate; Heisterkamp, Simon; Helary, Louis; Heller, Claudio; Heller, Matthieu; Hellman, Sten; Hellmich, Dennis; Helsens, Clement; Henderson, Robert; Henke, Michael; Henrichs, Anna; Henriques Correia, Ana Maria; Henrot-Versille, Sophie; Henry-Couannier, Frédéric; Hensel, Carsten; Henß, Tobias; Medina Hernandez, Carlos; Hernández Jiménez, Yesenia; Herrberg, Ruth; Hershenhorn, Alon David; Herten, Gregor; Hertenberger, Ralf; Hervas, Luis; Hesketh, Gavin Grant; Hessey, Nigel; Higón-Rodriguez, Emilio; Hill, Daniel; Hill, John; Hill, Norman; Hiller, Karl Heinz; Hillert, Sonja; Hillier, Stephen; Hinchliffe, Ian; Hines, Elizabeth; Hirose, Minoru; Hirsch, Florian; Hirschbuehl, Dominic; Hobbs, John; Hod, Noam; Hodgkinson, Mark; Hodgson, Paul; Hoecker, Andreas; Hoeferkamp, Martin; Hoffman, Julia; Hoffmann, Dirk; Hohlfeld, Marc; Holder, Martin; Holmgren, Sven-Olof; Holy, Tomas; Holzbauer, Jenny; Homma, Yasuhiro; Hong, Tae Min; Hooft van Huysduynen, Loek; Horazdovsky, Tomas; Horn, Claus; Horner, Stephan; Hostachy, Jean-Yves; Hou, Suen; Houlden, Michael; Hoummada, Abdeslam; Howarth, James; Howell, David; Hristova, Ivana; Hrivnac, Julius; Hruska, Ivan; Hryn'ova, Tetiana; Hsu, Pai-hsien Jennifer; Hsu, Shih-Chieh; Huang, Guang Shun; Hubacek, Zdenek; Hubaut, Fabrice; Huegging, Fabian; Huettmann, Antje; Huffman, Todd Brian; Hughes, Emlyn; Hughes, Gareth; Hughes-Jones, Richard; Huhtinen, Mika; Hurst, Peter; Hurwitz, Martina; Husemann, Ulrich; Huseynov, Nazim; Huston, Joey; Huth, John; Iacobucci, Giuseppe; Iakovidis, Georgios; Ibbotson, Michael; Ibragimov, Iskander; Ichimiya, Ryo; Iconomidou-Fayard, Lydia; Idarraga, John; Iengo, Paolo; Igonkina, Olga; Ikegami, Yoichi; Ikeno, Masahiro; Ilchenko, Yuri; Iliadis, Dimitrios; Ilic, Nikolina; Imori, Masatoshi; Ince, Tayfun; Inigo-Golfin, Joaquin; Ioannou, Pavlos; Iodice, Mauro; Ippolito, Valerio; Irles Quiles, Adrian; Isaksson, Charlie; Ishikawa, Akimasa; Ishino, Masaya; Ishmukhametov, Renat; Issever, Cigdem; Istin, Serhat; Ivashin, Anton; Iwanski, Wieslaw; Iwasaki, Hiroyuki; Izen, Joseph; Izzo, Vincenzo; Jackson, Brett; Jackson, John; Jackson, Paul; Jaekel, Martin; Jain, Vivek; Jakobs, Karl; Jakobsen, Sune; Jakubek, Jan; Jana, Dilip; Jankowski, Ernest; Jansen, Eric; Jansen, Hendrik; Jantsch, Andreas; Janus, Michel; Jarlskog, Göran; Jeanty, Laura; Jelen, Kazimierz; Jen-La Plante, Imai; Jenni, Peter; Jeremie, Andrea; Jež, Pavel; Jézéquel, Stéphane; Jha, Manoj Kumar; Ji, Haoshuang; Ji, Weina; Jia, Jiangyong; Jiang, Yi; Jimenez Belenguer, Marcos; Jin, Ge; Jin, Shan; Jinnouchi, Osamu; Joergensen, Morten Dam; Joffe, David; Johansen, Lars; Johansen, Marianne; Johansson, Erik; Johansson, Per; Johnert, Sebastian; Johns, Kenneth; Jon-And, Kerstin; Jones, Graham; Jones, Roger; Jones, Tegid; Jones, Tim; Jonsson, Ove; Joram, Christian; Jorge, Pedro; Joseph, John; Jovicevic, Jelena; Jovin, Tatjana; Ju, Xiangyang; Jung, Christian; Jungst, Ralph Markus; Juranek, Vojtech; Jussel, Patrick; Juste Rozas, Aurelio; Kabachenko, Vasily; Kabana, Sonja; Kaci, Mohammed; Kaczmarska, Anna; Kadlecik, Peter; Kado, Marumi; Kagan, Harris; Kagan, Michael; Kaiser, Steffen; Kajomovitz, Enrique; Kalinin, Sergey; Kalinovskaya, Lidia; Kama, Sami; Kanaya, Naoko; Kaneda, Michiru; Kaneti, Steven; Kanno, Takayuki; Kantserov, Vadim; Kanzaki, Junichi; Kaplan, Benjamin; Kapliy, Anton; Kaplon, Jan; Kar, Deepak; Karagounis, Michael; Karagoz, Muge; Karnevskiy, Mikhail; Karr, Kristo; Kartvelishvili, Vakhtang; Karyukhin, Andrey; Kashif, Lashkar; Kasieczka, Gregor; Kass, Richard; Kastanas, Alex; Kataoka, Mayuko; Kataoka, Yousuke; Katsoufis, Elias; Katzy, Judith; Kaushik, Venkatesh; Kawagoe, Kiyotomo; Kawamoto, Tatsuo; Kawamura, Gen; Kayl, Manuel; Kazanin, Vassili; Kazarinov, Makhail; Keeler, Richard; Kehoe, Robert; Keil, Markus; Kekelidze, George; Kennedy, John; Kenney, Christopher John; Kenyon, Mike; Kepka, Oldrich; Kerschen, Nicolas; Kerševan, Borut Paul; Kersten, Susanne; Kessoku, Kohei; Keung, Justin; Khalil-zada, Farkhad; Khandanyan, Hovhannes; Khanov, Alexander; Kharchenko, Dmitri; Khodinov, Alexander; Kholodenko, Anatoli; Khomich, Andrei; Khoo, Teng Jian; Khoriauli, Gia; Khoroshilov, Andrey; Khovanskiy, Nikolai; Khovanskiy, Valery; Khramov, Evgeniy; Khubua, Jemal; Kim, Hyeon Jin; Kim, Min Suk; Kim, Shinhong; Kimura, Naoki; Kind, Oliver; King, Barry; King, Matthew; King, Robert Steven Beaufoy; Kirk, Julie; Kirsch, Lawrence; Kiryunin, Andrey; Kishimoto, Tomoe; Kisielewska, Danuta; Kittelmann, Thomas; Kiver, Andrey; Kladiva, Eduard; Klaiber-Lodewigs, Jonas; Klein, Max; Klein, Uta; Kleinknecht, Konrad; Klemetti, Miika; Klier, Amit; Klimek, Pawel; Klimentov, Alexei; Klingenberg, Reiner; Klinger, Joel Alexander; Klinkby, Esben; Klioutchnikova, Tatiana; Klok, Peter; Klous, Sander; Kluge, Eike-Erik; Kluge, Thomas; Kluit, Peter; Kluth, Stefan; Knecht, Neil; Kneringer, Emmerich; Knobloch, Juergen; Knoops, Edith; Knue, Andrea; Ko, Byeong Rok; Kobayashi, Tomio; Kobel, Michael; Kocian, Martin; Kodys, Peter; Köneke, Karsten; König, Adriaan; Koenig, Sebastian; Köpke, Lutz; Koetsveld, Folkert; Koevesarki, Peter; Koffas, Thomas; Koffeman, Els; Kogan, Lucy Anne; Kohn, Fabian; Kohout, Zdenek; Kohriki, Takashi; Koi, Tatsumi; Kokott, Thomas; Kolachev, Guennady; Kolanoski, Hermann; Kolesnikov, Vladimir; Koletsou, Iro; Koll, James; Kollefrath, Michael; Kolya, Scott; Komar, Aston; Komori, Yuto; Kondo, Takahiko; Kono, Takanori; Kononov, Anatoly; Konoplich, Rostislav; Konstantinidis, Nikolaos; Kootz, Andreas; Koperny, Stefan; Korcyl, Krzysztof; Kordas, Kostantinos; Koreshev, Victor; Korn, Andreas; Korol, Aleksandr; Korolkov, Ilya; Korolkova, Elena; Korotkov, Vladislav; Kortner, Oliver; Kortner, Sandra; Kostyukhin, Vadim; Kotamäki, Miikka Juhani; Kotov, Sergey; Kotov, Vladislav; Kotwal, Ashutosh; Kourkoumelis, Christine; Kouskoura, Vasiliki; Koutsman, Alex; Kowalewski, Robert Victor; Kowalski, Tadeusz; Kozanecki, Witold; Kozhin, Anatoly; Kral, Vlastimil; Kramarenko, Viktor; Kramberger, Gregor; Krasny, Mieczyslaw Witold; Krasznahorkay, Attila; Kraus, James; Kraus, Jana; Kreisel, Arik; Krejci, Frantisek; Kretzschmar, Jan; Krieger, Nina; Krieger, Peter; Kroeninger, Kevin; Kroha, Hubert; Kroll, Joe; Kroseberg, Juergen; Krstic, Jelena; Kruchonak, Uladzimir; Krüger, Hans; Kruker, Tobias; Krumnack, Nils; Krumshteyn, Zinovii; Kruth, Andre; Kubota, Takashi; Kuday, Sinan; Kuehn, Susanne; Kugel, Andreas; Kuhl, Thorsten; Kuhn, Dietmar; Kukhtin, Victor; Kulchitsky, Yuri; Kuleshov, Sergey; Kummer, Christian; Kuna, Marine; Kundu, Nikhil; Kunkle, Joshua; Kupco, Alexander; Kurashige, Hisaya; Kurata, Masakazu; Kurochkin, Yurii; Kus, Vlastimil; Kuwertz, Emma Sian; Kuze, Masahiro; Kvita, Jiri; Kwee, Regina; La Rosa, Alessandro; La Rotonda, Laura; Labarga, Luis; Labbe, Julien; Lablak, Said; Lacasta, Carlos; Lacava, Francesco; Lacker, Heiko; Lacour, Didier; Lacuesta, Vicente Ramón; Ladygin, Evgueni; Lafaye, Remi; Laforge, Bertrand; Lagouri, Theodota; Lai, Stanley; Laisne, Emmanuel; Lamanna, Massimo; Lampen, Caleb; Lampl, Walter; Lancon, Eric; Landgraf, Ulrich; Landon, Murrough; Lane, Jenna; Lange, Clemens; Lankford, Andrew; Lanni, Francesco; Lantzsch, Kerstin; Laplace, Sandrine; Lapoire, Cecile; Laporte, Jean-Francois; Lari, Tommaso; Larionov, Anatoly; Larner, Aimee; Lasseur, Christian; Lassnig, Mario; Laurelli, Paolo; Lavorini, Vincenzo; Lavrijsen, Wim; Laycock, Paul; Lazarev, Alexandre; Le Dortz, Olivier; Le Guirriec, Emmanuel; Le Maner, Christophe; Le Menedeu, Eve; Lebel, Céline; LeCompte, Thomas; Ledroit-Guillon, Fabienne Agnes Marie; Lee, Hurng-Chun; Lee, Jason; Lee, Shih-Chang; Lee, Lawrence; Lefebvre, Michel; Legendre, Marie; Leger, Annie; LeGeyt, Benjamin; Legger, Federica; Leggett, Charles; Lehmacher, Marc; Lehmann Miotto, Giovanna; Lei, Xiaowen; Leite, Marco Aurelio Lisboa; Leitner, Rupert; Lellouch, Daniel; Leltchouk, Mikhail; Lemmer, Boris; Lendermann, Victor; Leney, Katharine; Lenz, Tatiana; Lenzen, Georg; Lenzi, Bruno; Leonhardt, Kathrin; Leontsinis, Stefanos; Leroy, Claude; Lessard, Jean-Raphael; Lesser, Jonas; Lester, Christopher; Leung Fook Cheong, Annabelle; Levêque, Jessica; Levin, Daniel; Levinson, Lorne; Levitski, Mikhail; Lewis, Adrian; Lewis, George; Leyko, Agnieszka; Leyton, Michael; Li, Bo; Li, Haifeng; Li, Shu; Li, Xuefei; Liang, Zhijun; Liao, Hongbo; Liberti, Barbara; Lichard, Peter; Lichtnecker, Markus; Lie, Ki; Liebig, Wolfgang; Lifshitz, Ronen; Limbach, Christian; Limosani, Antonio; Limper, Maaike; Lin, Simon; Linde, Frank; Linnemann, James; Lipeles, Elliot; Lipinsky, Lukas; Lipniacka, Anna; Liss, Tony; Lissauer, David; Lister, Alison; Litke, Alan; Liu, Chuanlei; Liu, Dong; Liu, Hao; Liu, Jianbei; Liu, Minghui; Liu, Yanwen; Livan, Michele; Livermore, Sarah; Lleres, Annick; Llorente Merino, Javier; Lloyd, Stephen; Lobodzinska, Ewelina; Loch, Peter; Lockman, William; Loddenkoetter, Thomas; Loebinger, Fred; Loginov, Andrey; Loh, Chang Wei; Lohse, Thomas; Lohwasser, Kristin; Lokajicek, Milos; Loken, James; Lombardo, Vincenzo Paolo; Long, Robin Eamonn; Lopes, Lourenco; Lopez Mateos, David; Lorenz, Jeanette; Lorenzo Martinez, Narei; Losada, Marta; Loscutoff, Peter; Lo Sterzo, Francesco; Losty, Michael; Lou, Xinchou; Lounis, Abdenour; Loureiro, Karina; Love, Jeremy; Love, Peter; Lowe, Andrew; Lu, Feng; Lubatti, Henry; Luci, Claudio; Lucotte, Arnaud; Ludwig, Andreas; Ludwig, Dörthe; Ludwig, Inga; Ludwig, Jens; Luehring, Frederick; Luijckx, Guy; Lumb, Debra; Luminari, Lamberto; Lund, Esben; Lund-Jensen, Bengt; Lundberg, Björn; Lundberg, Johan; Lundquist, Johan; Lungwitz, Matthias; Lutz, Gerhard; Lynn, David; Lys, Jeremy; Lytken, Else; Ma, Hong; Ma, Lian Liang; Macana Goia, Jorge Andres; Maccarrone, Giovanni; Macchiolo, Anna; Maček, Boštjan; Machado Miguens, Joana; Mackeprang, Rasmus; Madaras, Ronald; Mader, Wolfgang; Maenner, Reinhard; Maeno, Tadashi; Mättig, Peter; Mättig, Stefan; Magnoni, Luca; Magradze, Erekle; Mahalalel, Yair; Mahboubi, Kambiz; Mahout, Gilles; Maiani, Camilla; Maidantchik, Carmen; Maio, Amélia; Majewski, Stephanie; Makida, Yasuhiro; Makovec, Nikola; Mal, Prolay; Malaescu, Bogdan; Malecki, Pawel; Malecki, Piotr; Maleev, Victor; Malek, Fairouz; Mallik, Usha; Malon, David; Malone, Caitlin; Maltezos, Stavros; Malyshev, Vladimir; Malyukov, Sergei; Mameghani, Raphael; Mamuzic, Judita; Manabe, Atsushi; Mandelli, Luciano; Mandić, Igor; Mandrysch, Rocco; Maneira, José; Mangeard, Pierre-Simon; Manhaes de Andrade Filho, Luciano; Manjavidze, Ioseb; Mann, Alexander; Manning, Peter; Manousakis-Katsikakis, Arkadios; Mansoulie, Bruno; Manz, Andreas; Mapelli, Alessandro; Mapelli, Livio; March, Luis; Marchand, Jean-Francois; Marchese, Fabrizio; Marchiori, Giovanni; Marcisovsky, Michal; Marino, Christopher; Marroquim, Fernando; Marshall, Robin; Marshall, Zach; Martens, Kalen; Marti-Garcia, Salvador; Martin, Andrew; Martin, Brian; Martin, Brian Thomas; Martin, Franck Francois; Martin, Jean-Pierre; Martin, Philippe; Martin, Tim; Martin, Victoria Jane; Martin dit Latour, Bertrand; Martin-Haugh, Stewart; Martinez, Mario; Martinez Outschoorn, Verena; Martyniuk, Alex; Marx, Marilyn; Marzano, Francesco; Marzin, Antoine; Masetti, Lucia; Mashimo, Tetsuro; Mashinistov, Ruslan; Masik, Jiri; Maslennikov, Alexey; Massa, Ignazio; Massaro, Graziano; Massol, Nicolas; Mastrandrea, Paolo; Mastroberardino, Anna; Masubuchi, Tatsuya; Matricon, Pierre; Matsumoto, Hiroshi; Matsunaga, Hiroyuki; Matsushita, Takashi; Mattravers, Carly; Maugain, Jean-Marie; Maurer, Julien; Maxfield, Stephen; Maximov, Dmitriy; May, Edward; Mayne, Anna; Mazini, Rachid; Mazur, Michael; Mazzanti, Marcello; Mc Kee, Shawn Patrick; McCarn, Allison; McCarthy, Robert; McCarthy, Tom; McCubbin, Norman; McFarlane, Kenneth; Mcfayden, Josh; McGlone, Helen; Mchedlidze, Gvantsa; McLaren, Robert Andrew; Mclaughlan, Tom; McMahon, Steve; McPherson, Robert; Meade, Andrew; Mechnich, Joerg; Mechtel, Markus; Medinnis, Mike; Meera-Lebbai, Razzak; Meguro, Tatsuma; Mehdiyev, Rashid; Mehlhase, Sascha; Mehta, Andrew; Meier, Karlheinz; Meirose, Bernhard; Melachrinos, Constantinos; Mellado Garcia, Bruce Rafael; Mendoza Navas, Luis; Meng, Zhaoxia; Mengarelli, Alberto; Menke, Sven; Menot, Claude; Meoni, Evelin; Mercurio, Kevin Michael; Mermod, Philippe; Merola, Leonardo; Meroni, Chiara; Merritt, Frank; Merritt, Hayes; Messina, Andrea; Metcalfe, Jessica; Mete, Alaettin Serhan; Meyer, Carsten; Meyer, Christopher; Meyer, Jean-Pierre; Meyer, Jochen; Meyer, Joerg; Meyer, Thomas Christian; Meyer, W Thomas; Miao, Jiayuan; Michal, Sebastien; Micu, Liliana; Middleton, Robin; Migas, Sylwia; Mijović, Liza; Mikenberg, Giora; Mikestikova, Marcela; Mikuž, Marko; Miller, David; Miller, Robert; Mills, Bill; Mills, Corrinne; Milov, Alexander; Milstead, David; Milstein, Dmitry; Minaenko, Andrey; Miñano Moya, Mercedes; Minashvili, Irakli; Mincer, Allen; Mindur, Bartosz; Mineev, Mikhail; Ming, Yao; Mir, Lluisa-Maria; Mirabelli, Giovanni; Miralles Verge, Lluis; Misiejuk, Andrzej; Mitrevski, Jovan; Mitrofanov, Gennady; Mitsou, Vasiliki A; Mitsui, Shingo; Miyagawa, Paul; Miyazaki, Kazuki; Mjörnmark, Jan-Ulf; Moa, Torbjoern; Mockett, Paul; Moed, Shulamit; Moeller, Victoria; Mönig, Klaus; Möser, Nicolas; Mohapatra, Soumya; Mohr, Wolfgang; Mohrdieck-Möck, Susanne; Moisseev, Artemy; Moles-Valls, Regina; Molina-Perez, Jorge; Monk, James; Monnier, Emmanuel; Montesano, Simone; Monticelli, Fernando; Monzani, Simone; Moore, Roger; Moorhead, Gareth; Mora Herrera, Clemencia; Moraes, Arthur; Morange, Nicolas; Morel, Julien; Morello, Gianfranco; Moreno, Deywis; Moreno Llácer, María; Morettini, Paolo; Morgenstern, Marcus; Morii, Masahiro; Morin, Jerome; Morley, Anthony Keith; Mornacchi, Giuseppe; Morozov, Sergey; Morris, John; Morvaj, Ljiljana; Moser, Hans-Guenther; Mosidze, Maia; Moss, Josh; Mount, Richard; Mountricha, Eleni; Mouraviev, Sergei; Moyse, Edward; Mudrinic, Mihajlo; Mueller, Felix; Mueller, James; Mueller, Klemens; Müller, Thomas; Mueller, Timo; Muenstermann, Daniel; Muir, Alex; Munwes, Yonathan; Murray, Bill; Mussche, Ido; Musto, Elisa; Myagkov, Alexey; Myska, Miroslav; Nadal, Jordi; Nagai, Koichi; Nagano, Kunihiro; Nagarkar, Advait; Nagasaka, Yasushi; Nagel, Martin; Nairz, Armin Michael; Nakahama, Yu; Nakamura, Koji; Nakamura, Tomoaki; Nakano, Itsuo; Nanava, Gizo; Napier, Austin; Narayan, Rohin; Nash, Michael; Nation, Nigel; Nattermann, Till; Naumann, Thomas; Navarro, Gabriela; Neal, Homer; Nebot, Eduardo; Nechaeva, Polina; Neep, Thomas James; Negri, Andrea; Negri, Guido; Nektarijevic, Snezana; Nelson, Andrew; Nelson, Silke; Nelson, Timothy Knight; Nemecek, Stanislav; Nemethy, Peter; Nepomuceno, Andre Asevedo; Nessi, Marzio; Neubauer, Mark; Neusiedl, Andrea; Neves, Ricardo; Nevski, Pavel; Newman, Paul; Nguyen Thi Hong, Van; Nickerson, Richard; Nicolaidou, Rosy; Nicolas, Ludovic; Nicquevert, Bertrand; Niedercorn, Francois; Nielsen, Jason; Niinikoski, Tapio; Nikiforou, Nikiforos; Nikiforov, Andriy; Nikolaenko, Vladimir; Nikolaev, Kirill; Nikolic-Audit, Irena; Nikolics, Katalin; Nikolopoulos, Konstantinos; Nilsen, Henrik; Nilsson, Paul; Ninomiya, Yoichi; Nisati, Aleandro; Nishiyama, Tomonori; Nisius, Richard; Nodulman, Lawrence; Nomachi, Masaharu; Nomidis, Ioannis; Nordberg, Markus; Nordkvist, Bjoern; Norton, Peter; Novakova, Jana; Nozaki, Mitsuaki; Nozka, Libor; Nugent, Ian Michael; Nuncio-Quiroz, Adriana-Elizabeth; Nunes Hanninger, Guilherme; Nunnemann, Thomas; Nurse, Emily; O'Brien, Brendan Joseph; O'Neale, Steve; O'Neil, Dugan; O'Shea, Val; Oakes, Louise Beth; Oakham, Gerald; Oberlack, Horst; Ocariz, Jose; Ochi, Atsuhiko; Oda, Susumu; Odaka, Shigeru; Odier, Jerome; Ogren, Harold; Oh, Alexander; Oh, Seog; Ohm, Christian; Ohshima, Takayoshi; Ohshita, Hidetoshi; Ohsugi, Takashi; Okada, Shogo; Okawa, Hideki; Okumura, Yasuyuki; Okuyama, Toyonobu; Olariu, Albert; Olcese, Marco; Olchevski, Alexander; Olivares Pino, Sebastian Andres; Oliveira, Miguel Alfonso; Oliveira Damazio, Denis; Oliver Garcia, Elena; Olivito, Dominick; Olszewski, Andrzej; Olszowska, Jolanta; Omachi, Chihiro; Onofre, António; Onyisi, Peter; Oram, Christopher; Oreglia, Mark; Oren, Yona; Orestano, Domizia; Orlov, Iliya; Oropeza Barrera, Cristina; Orr, Robert; Osculati, Bianca; Ospanov, Rustem; Osuna, Carlos; Otero y Garzon, Gustavo; Ottersbach, John; Ouchrif, Mohamed; Ouellette, Eric; Ould-Saada, Farid; Ouraou, Ahmimed; Ouyang, Qun; Ovcharova, Ana; Owen, Mark; Owen, Simon; Ozcan, Veysi Erkcan; Ozturk, Nurcan; Pacheco Pages, Andres; Padilla Aranda, Cristobal; Pagan Griso, Simone; Paganis, Efstathios; Paige, Frank; Pais, Preema; Pajchel, Katarina; Palacino, Gabriel; Paleari, Chiara; Palestini, Sandro; Pallin, Dominique; Palma, Alberto; Palmer, Jody; Pan, Yibin; Panagiotopoulou, Evgenia; Panes, Boris; Panikashvili, Natalia; Panitkin, Sergey; Pantea, Dan; Panuskova, Monika; Paolone, Vittorio; Papadelis, Aras; Papadopoulou, Theodora; Paramonov, Alexander; Paredes Hernandez, Daniela; Park, Woochun; Parker, Andy; Parodi, Fabrizio; Parsons, John; Parzefall, Ulrich; Pasqualucci, Enrico; Passaggio, Stefano; Passeri, Antonio; Pastore, Fernanda; Pastore, Francesca; Pásztor, Gabriella; Pataraia, Sophio; Patel, Nikhul; Pater, Joleen; Patricelli, Sergio; Pauly, Thilo; Pecsy, Martin; Pedraza Morales, Maria Isabel; Peleganchuk, Sergey; Peng, Haiping; Pengo, Ruggero; Penning, Bjoern; Penson, Alexander; Penwell, John; Perantoni, Marcelo; Perez, Kerstin; Perez Cavalcanti, Tiago; Perez Codina, Estel; Pérez García-Estañ, María Teresa; Perez Reale, Valeria; Perini, Laura; Pernegger, Heinz; Perrino, Roberto; Perrodo, Pascal; Persembe, Seda; Perus, Antoine; Peshekhonov, Vladimir; Peters, Krisztian; Petersen, Brian; Petersen, Jorgen; Petersen, Troels; Petit, Elisabeth; Petridis, Andreas; Petridou, Chariclia; Petrolo, Emilio; Petrucci, Fabrizio; Petschull, Dennis; Petteni, Michele; Pezoa, Raquel; Phan, Anna; Phillips, Peter William; Piacquadio, Giacinto; Picazio, Attilio; Piccaro, Elisa; Piccinini, Maurizio; Piec, Sebastian Marcin; Piegaia, Ricardo; Pignotti, David; Pilcher, James; Pilkington, Andrew; Pina, João Antonio; Pinamonti, Michele; Pinder, Alex; Pinfold, James; Ping, Jialun; Pinto, Belmiro; Pirotte, Olivier; Pizio, Caterina; Plamondon, Mathieu; Pleier, Marc-Andre; Pleskach, Anatoly; Poblaguev, Andrei; Poddar, Sahill; Podlyski, Fabrice; Poggioli, Luc; Poghosyan, Tatevik; Pohl, Martin; Polci, Francesco; Polesello, Giacomo; Policicchio, Antonio; Polini, Alessandro; Poll, James; Polychronakos, Venetios; Pomarede, Daniel Marc; Pomeroy, Daniel; Pommès, Kathy; Pontecorvo, Ludovico; Pope, Bernard; Popeneciu, Gabriel Alexandru; Popovic, Dragan; Poppleton, Alan; Portell Bueso, Xavier; Posch, Christoph; Pospelov, Guennady; Pospisil, Stanislav; Potrap, Igor; Potter, Christina; Potter, Christopher; Poulard, Gilbert; Poveda, Joaquin; Pozdnyakov, Valery; Prabhu, Robindra; Pralavorio, Pascal; Pranko, Aliaksandr; Prasad, Srivas; Pravahan, Rishiraj; Prell, Soeren; Pretzl, Klaus Peter; Pribyl, Lukas; Price, Darren; Price, Joe; Price, Lawrence; Price, Michael John; Prieur, Damien; Primavera, Margherita; Prokofiev, Kirill; Prokoshin, Fedor; Protopopescu, Serban; Proudfoot, James; Prudent, Xavier; Przybycien, Mariusz; Przysiezniak, Helenka; Psoroulas, Serena; Ptacek, Elizabeth; Pueschel, Elisa; Purdham, John; Purohit, Milind; Puzo, Patrick; Pylypchenko, Yuriy; Qian, Jianming; Qian, Zuxuan; Qin, Zhonghua; Quadt, Arnulf; Quarrie, David; Quayle, William; Quinonez, Fernando; Raas, Marcel; Radescu, Voica; Radics, Balint; Radloff, Peter; Rador, Tonguc; Ragusa, Francesco; Rahal, Ghita; Rahimi, Amir; Rahm, David; Rajagopalan, Srinivasan; Rammensee, Michael; Rammes, Marcus; Randle-Conde, Aidan Sean; Randrianarivony, Koloina; Ratoff, Peter; Rauscher, Felix; Rave, Tobias Christian; Raymond, Michel; Read, Alexander Lincoln; Rebuzzi, Daniela; Redelbach, Andreas; Redlinger, George; Reece, Ryan; Reeves, Kendall; Reichold, Armin; Reinherz-Aronis, Erez; Reinsch, Andreas; Reisinger, Ingo; Rembser, Christoph; Ren, Zhongliang; Renaud, Adrien; Rescigno, Marco; Resconi, Silvia; Resende, Bernardo; Reznicek, Pavel; Rezvani, Reyhaneh; Richards, Alexander; Richter, Robert; Richter-Was, Elzbieta; Ridel, Melissa; Rijpstra, Manouk; Rijssenbeek, Michael; Rimoldi, Adele; Rinaldi, Lorenzo; Rios, Ryan Randy; Riu, Imma; Rivoltella, Giancesare; Rizatdinova, Flera; Rizvi, Eram; Robertson, Steven; Robichaud-Veronneau, Andree; Robinson, Dave; Robinson, James; Robson, Aidan; Rocha de Lima, Jose Guilherme; Roda, Chiara; Roda Dos Santos, Denis; Rodriguez, Diego; Roe, Adam; Roe, Shaun; Røhne, Ole; Rojo, Victoria; Rolli, Simona; Romaniouk, Anatoli; Romano, Marino; Romanov, Victor; Romeo, Gaston; Romero Adam, Elena; Roos, Lydia; Ros, Eduardo; Rosati, Stefano; Rosbach, Kilian; Rose, Anthony; Rose, Matthew; Rosenbaum, Gabriel; Rosenberg, Eli; Rosendahl, Peter Lundgaard; Rosenthal, Oliver; Rosselet, Laurent; Rossetti, Valerio; Rossi, Elvira; Rossi, Leonardo Paolo; Rotaru, Marina; Roth, Itamar; Rothberg, Joseph; Rousseau, David; Royon, Christophe; Rozanov, Alexander; Rozen, Yoram; Ruan, Xifeng; Rubinskiy, Igor; Ruckert, Benjamin; Ruckstuhl, Nicole; Rud, Viacheslav; Rudolph, Christian; Rudolph, Gerald; Rühr, Frederik; Ruggieri, Federico; Ruiz-Martinez, Aranzazu; Rumiantsev, Viktor; Rumyantsev, Leonid; Runge, Kay; Rurikova, Zuzana; Rusakovich, Nikolai; Rutherfoord, John; Ruwiedel, Christoph; Ruzicka, Pavel; Ryabov, Yury; Ryadovikov, Vasily; Ryan, Patrick; Rybar, Martin; Rybkin, Grigori; Ryder, Nick; Rzaeva, Sevda; Saavedra, Aldo; Sadeh, Iftach; Sadrozinski, Hartmut; Sadykov, Renat; Safai Tehrani, Francesco; Sakamoto, Hiroshi; Salamanna, Giuseppe; Salamon, Andrea; Saleem, Muhammad; Salihagic, Denis; Salnikov, Andrei; Salt, José; Salvachua Ferrando, Belén; Salvatore, Daniela; Salvatore, Pasquale Fabrizio; Salvucci, Antonio; Salzburger, Andreas; Sampsonidis, Dimitrios; Samset, Björn Hallvard; Sanchez, Arturo; Sanchez Martinez, Victoria; Sandaker, Heidi; Sander, Heinz Georg; Sanders, Michiel; Sandhoff, Marisa; Sandoval, Tanya; Sandoval, Carlos; Sandstroem, Rikard; Sandvoss, Stephan; Sankey, Dave; Sansoni, Andrea; Santamarina Rios, Cibran; Santoni, Claudio; Santonico, Rinaldo; Santos, Helena; Saraiva, João; Sarangi, Tapas; Sarkisyan-Grinbaum, Edward; Sarri, Francesca; Sartisohn, Georg; Sasaki, Osamu; Sasao, Noboru; Satsounkevitch, Igor; Sauvage, Gilles; Sauvan, Emmanuel; Sauvan, Jean-Baptiste; Savard, Pierre; Savinov, Vladimir; Savu, Dan Octavian; Sawyer, Lee; Saxon, David; Says, Louis-Pierre; Sbarra, Carla; Sbrizzi, Antonio; Scallon, Olivia; Scannicchio, Diana; Scarcella, Mark; Schaarschmidt, Jana; Schacht, Peter; Schäfer, Uli; Schaepe, Steffen; Schaetzel, Sebastian; Schaffer, Arthur; Schaile, Dorothee; Schamberger, R. Dean; Schamov, Andrey; Scharf, Veit; Schegelsky, Valery; Scheirich, Daniel; Schernau, Michael; Scherzer, Max; Schiavi, Carlo; Schieck, Jochen; Schioppa, Marco; Schlenker, Stefan; Schlereth, James; Schmidt, Evelyn; Schmieden, Kristof; Schmitt, Christian; Schmitt, Sebastian; Schmitz, Martin; Schöning, André; Schott, Matthias; Schouten, Doug; Schovancova, Jaroslava; Schram, Malachi; Schroeder, Christian; Schroer, Nicolai; Schuler, Georges; Schultens, Martin Johannes; Schultes, Joachim; Schultz-Coulon, Hans-Christian; Schulz, Holger; Schumacher, Jan; Schumacher, Markus; Schumm, Bruce; Schune, Philippe; Schwanenberger, Christian; Schwartzman, Ariel; Schwemling, Philippe; Schwienhorst, Reinhard; Schwierz, Rainer; Schwindling, Jerome; Schwindt, Thomas; Schwoerer, Maud; Scott, Bill; Searcy, Jacob; Sedov, George; Sedykh, Evgeny; Segura, Ester; Seidel, Sally; Seiden, Abraham; Seifert, Frank; Seixas, José; Sekhniaidze, Givi; Selbach, Karoline Elfriede; Seliverstov, Dmitry; Sellden, Bjoern; Sellers, Graham; Seman, Michal; Semprini-Cesari, Nicola; Serfon, Cedric; Serin, Laurent; Serkin, Leonid; Seuster, Rolf; Severini, Horst; Sevior, Martin; Sfyrla, Anna; Shabalina, Elizaveta; Shamim, Mansoora; Shan, Lianyou; Shank, James; Shao, Qi Tao; Shapiro, Marjorie; Shatalov, Pavel; Shaver, Leif; Shaw, Kate; Sherman, Daniel; Sherwood, Peter; Shibata, Akira; Shichi, Hideharu; Shimizu, Shima; Shimojima, Makoto; Shin, Taeksu; Shiyakova, Maria; Shmeleva, Alevtina; Shochet, Mel; Short, Daniel; Shrestha, Suyog; Shulga, Evgeny; Shupe, Michael; Sicho, Petr; Sidoti, Antonio; Siegert, Frank; Sijacki, Djordje; Silbert, Ohad; Silva, José; Silver, Yiftah; Silverstein, Daniel; Silverstein, Samuel; Simak, Vladislav; Simard, Olivier; Simic, Ljiljana; Simion, Stefan; Simmons, Brinick; Simonyan, Margar; Sinervo, Pekka; Sinev, Nikolai; Sipica, Valentin; Siragusa, Giovanni; Sircar, Anirvan; Sisakyan, Alexei; Sivoklokov, Serguei; Sjölin, Jörgen; Sjursen, Therese; Skinnari, Louise Anastasia; Skottowe, Hugh Philip; Skovpen, Kirill; Skubic, Patrick; Skvorodnev, Nikolai; Slater, Mark; Slavicek, Tomas; Sliwa, Krzysztof; Sloper, John erik; Smakhtin, Vladimir; Smart, Ben; Smirnov, Sergei; Smirnov, Yury; Smirnova, Lidia; Smirnova, Oxana; Smith, Ben Campbell; Smith, Douglas; Smith, Kenway; Smizanska, Maria; Smolek, Karel; Snesarev, Andrei; Snow, Steve; Snow, Joel; Snuverink, Jochem; Snyder, Scott; Soares, Mara; Sobie, Randall; Sodomka, Jaromir; Soffer, Abner; Solans, Carlos; Solar, Michael; Solc, Jaroslav; Soldatov, Evgeny; Soldevila, Urmila; Solfaroli Camillocci, Elena; Solodkov, Alexander; Solovyanov, Oleg; Soni, Nitesh; Sopko, Vit; Sopko, Bruno; Sosebee, Mark; Soualah, Rachik; Soukharev, Andrey; Spagnolo, Stefania; Spanò, Francesco; Spighi, Roberto; Spigo, Giancarlo; Spila, Federico; Spiwoks, Ralf; Spousta, Martin; Spreitzer, Teresa; Spurlock, Barry; St Denis, Richard Dante; Stahlman, Jonathan; Stamen, Rainer; Stanecka, Ewa; Stanek, Robert; Stanescu, Cristian; Stapnes, Steinar; Starchenko, Evgeny; Stark, Jan; Staroba, Pavel; Starovoitov, Pavel; Staude, Arnold; Stavina, Pavel; Steele, Genevieve; Steinbach, Peter; Steinberg, Peter; Stekl, Ivan; Stelzer, Bernd; Stelzer, Harald Joerg; Stelzer-Chilton, Oliver; Stenzel, Hasko; Stern, Sebastian; Stevenson, Kyle; Stewart, Graeme; Stillings, Jan Andre; Stockton, Mark; Stoerig, Kathrin; Stoicea, Gabriel; Stonjek, Stefan; Strachota, Pavel; Stradling, Alden; Straessner, Arno; Strandberg, Jonas; Strandberg, Sara; Strandlie, Are; Strang, Michael; Strauss, Emanuel; Strauss, Michael; Strizenec, Pavol; Ströhmer, Raimund; Strom, David; Strong, John; Stroynowski, Ryszard; Strube, Jan; Stugu, Bjarne; Stumer, Iuliu; Stupak, John; Sturm, Philipp; Styles, Nicholas Adam; Soh, Dart-yin; Su, Dong; Subramania, Halasya Siva; Succurro, Antonella; Sugaya, Yorihito; Sugimoto, Takuya; Suhr, Chad; Suita, Koichi; Suk, Michal; Sulin, Vladimir; Sultansoy, Saleh; Sumida, Toshi; Sun, Xiaohu; Sundermann, Jan Erik; Suruliz, Kerim; Sushkov, Serge; Susinno, Giancarlo; Sutton, Mark; Suzuki, Yu; Suzuki, Yuta; Svatos, Michal; Sviridov, Yuri; Swedish, Stephen; Sykora, Ivan; Sykora, Tomas; Szeless, Balazs; Sánchez, Javier; Ta, Duc; Tackmann, Kerstin; Taffard, Anyes; Tafirout, Reda; Taiblum, Nimrod; Takahashi, Yuta; Takai, Helio; Takashima, Ryuichi; Takeda, Hiroshi; Takeshita, Tohru; Takubo, Yosuke; Talby, Mossadek; Talyshev, Alexey; Tamsett, Matthew; Tanaka, Junichi; Tanaka, Reisaburo; Tanaka, Satoshi; Tanaka, Shuji; Tanaka, Yoshito; Tanasijczuk, Andres Jorge; Tani, Kazutoshi; Tannoury, Nancy; Tappern, Geoffrey; Tapprogge, Stefan; Tardif, Dominique; Tarem, Shlomit; Tarrade, Fabien; Tartarelli, Giuseppe Francesco; Tas, Petr; Tasevsky, Marek; Tassi, Enrico; Tatarkhanov, Mous; Tayalati, Yahya; Taylor, Christopher; Taylor, Frank; Taylor, Geoffrey; Taylor, Wendy; Teinturier, Marthe; Teixeira Dias Castanheira, Matilde; Teixeira-Dias, Pedro; Temming, Kim Katrin; Ten Kate, Herman; Teng, Ping-Kun; Terada, Susumu; Terashi, Koji; Terron, Juan; Testa, Marianna; Teuscher, Richard; Thadome, Jocelyn; Therhaag, Jan; Theveneaux-Pelzer, Timothée; Thioye, Moustapha; Thoma, Sascha; Thomas, Juergen; Thompson, Emily; Thompson, Paul; Thompson, Peter; Thompson, Stan; Thomsen, Lotte Ansgaard; Thomson, Evelyn; Thomson, Mark; Thun, Rudolf; Tian, Feng; Tibbetts, Mark James; Tic, Tomáš; Tikhomirov, Vladimir; Tikhonov, Yury; Timoshenko, Sergey; Tipton, Paul; Tique Aires Viegas, Florbela De Jes; Tisserant, Sylvain; Toczek, Barbara; Todorov, Theodore; Todorova-Nova, Sharka; Toggerson, Brokk; Tojo, Junji; Tokár, Stanislav; Tokunaga, Kaoru; Tokushuku, Katsuo; Tollefson, Kirsten; Tomoto, Makoto; Tompkins, Lauren; Toms, Konstantin; Tong, Guoliang; Tonoyan, Arshak; Topfel, Cyril; Topilin, Nikolai; Torchiani, Ingo; Torrence, Eric; Torres, Heberth; Torró Pastor, Emma; Toth, Jozsef; Touchard, Francois; Tovey, Daniel; Trefzger, Thomas; Tremblet, Louis; Tricoli, Alesandro; Trigger, Isabel Marian; Trincaz-Duvoid, Sophie; Trinh, Thi Nguyet; Tripiana, Martin; Trischuk, William; Trivedi, Arjun; Trocmé, Benjamin; Troncon, Clara; 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van der Graaf, Harry; van der Kraaij, Erik; Van Der Leeuw, Robin; van der Poel, Egge; van der Ster, Daniel; van Eldik, Niels; van Gemmeren, Peter; van Kesteren, Zdenko; van Vulpen, Ivo; Vanadia, Marco; Vandelli, Wainer; Vandoni, Giovanna; Vaniachine, Alexandre; Vankov, Peter; Vannucci, Francois; Varela Rodriguez, Fernando; Vari, Riccardo; Varnes, Erich; Varouchas, Dimitris; Vartapetian, Armen; Varvell, Kevin; Vassilakopoulos, Vassilios; Vazeille, Francois; Vazquez Schroeder, Tamara; Vegni, Guido; Veillet, Jean-Jacques; Vellidis, Constantine; Veloso, Filipe; Veness, Raymond; Veneziano, Stefano; Ventura, Andrea; Ventura, Daniel; Venturi, Manuela; Venturi, Nicola; Vercesi, Valerio; Verducci, Monica; Verkerke, Wouter; Vermeulen, Jos; Vest, Anja; Vetterli, Michel; Vichou, Irene; Vickey, Trevor; Vickey Boeriu, Oana Elena; Viehhauser, Georg; Viel, Simon; Villa, Mauro; Villaplana Perez, Miguel; Vilucchi, Elisabetta; Vincter, Manuella; Vinek, Elisabeth; Vinogradov, Vladimir; Virchaux, Marc; Virzi, Joseph; Vitells, Ofer; Viti, Michele; Vivarelli, Iacopo; Vives Vaque, Francesc; Vlachos, Sotirios; Vladoiu, Dan; Vlasak, Michal; Vlasov, Nikolai; Vogel, Adrian; Vokac, Petr; Volpi, Guido; Volpi, Matteo; Volpini, Giovanni; von der Schmitt, Hans; von Loeben, Joerg; von Radziewski, Holger; von Toerne, Eckhard; Vorobel, Vit; Vorobiev, Alexander; Vorwerk, Volker; Vos, Marcel; Voss, Rudiger; Voss, Thorsten Tobias; Vossebeld, Joost; Vranjes, Nenad; Vranjes Milosavljevic, Marija; Vrba, Vaclav; Vreeswijk, Marcel; Vu Anh, Tuan; Vuillermet, Raphael; Vukotic, Ilija; Wagner, Wolfgang; Wagner, Peter; Wahlen, Helmut; Wakabayashi, Jun; Walbersloh, Jorg; Walch, Shannon; Walder, James; Walker, Rodney; Walkowiak, Wolfgang; Wall, Richard; Waller, Peter; Wang, Chiho; Wang, Haichen; Wang, Hulin; Wang, Jike; Wang, Jin; Wang, Joshua C; Wang, Rui; Wang, Song-Ming; Warburton, Andreas; Ward, Patricia; Warsinsky, Markus; Watkins, Peter; Watson, Alan; Watson, Ian; Watson, Miriam; Watts, Gordon; Watts, Stephen; Waugh, Anthony; Waugh, Ben; Weber, Marc; Weber, Michele; Weber, Pavel; Weidberg, Anthony; Weigell, Philipp; Weingarten, Jens; Weiser, Christian; Wellenstein, Hermann; Wells, Phillippa; Wenaus, Torre; Wendland, Dennis; Wendler, Shanti; Weng, Zhili; Wengler, Thorsten; Wenig, Siegfried; Wermes, Norbert; Werner, Matthias; Werner, Per; Werth, Michael; Wessels, Martin; Weydert, Carole; Whalen, Kathleen; Wheeler-Ellis, Sarah Jane; Whitaker, Scott; White, Andrew; White, Martin; Whitehead, Samuel Robert; Whiteson, Daniel; Whittington, Denver; Wicek, Francois; Wicke, Daniel; Wickens, Fred; Wiedenmann, Werner; Wielers, Monika; Wienemann, Peter; Wiglesworth, Craig; Wiik-Fuchs, Liv Antje Mari; Wijeratne, Peter Alexander; Wildauer, Andreas; Wildt, Martin Andre; Wilhelm, Ivan; Wilkens, Henric George; Will, Jonas Zacharias; Williams, Eric; Williams, Hugh; Willis, William; Willocq, Stephane; Wilson, John; Wilson, Michael Galante; Wilson, Alan; Wingerter-Seez, Isabelle; Winkelmann, Stefan; Winklmeier, Frank; Wittgen, Matthias; Wolter, Marcin Wladyslaw; Wolters, Helmut; Wong, Wei-Cheng; Wooden, Gemma; Wosiek, Barbara; Wotschack, Jorg; Woudstra, Martin; Wozniak, Krzysztof; Wraight, Kenneth; Wright, Catherine; Wright, Michael; Wrona, Bozydar; Wu, Sau Lan; Wu, Xin; Wu, Yusheng; Wulf, Evan; Wunstorf, Renate; Wynne, Benjamin; Xella, Stefania; Xiao, Meng; Xie, Song; Xie, Yigang; Xu, Chao; Xu, Da; Xu, Guofa; Yabsley, Bruce; Yacoob, Sahal; Yamada, Miho; Yamaguchi, Hiroshi; Yamamoto, Akira; Yamamoto, Kyoko; Yamamoto, Shimpei; Yamamura, Taiki; Yamanaka, Takashi; Yamaoka, Jared; Yamazaki, Takayuki; Yamazaki, Yuji; Yan, Zhen; Yang, Haijun; Yang, Un-Ki; Yang, Yi; Yang, Yi; Yang, Zhaoyu; Yanush, Serguei; Yao, Yushu; Yasu, Yoshiji; Ybeles Smit, Gabriel Valentijn; Ye, Jingbo; Ye, Shuwei; Yilmaz, Metin; Yoosoofmiya, Reza; Yorita, Kohei; Yoshida, Riktura; Young, Charles; Youssef, Saul; Yu, Dantong; Yu, Jaehoon; Yu, Jie; Yuan, Li; Yurkewicz, Adam; Zabinski, Bartlomiej; Zaets, Vassilli; Zaidan, Remi; Zaitsev, Alexander; Zajacova, Zuzana; Zanello, Lucia; Zaytsev, Alexander; Zeitnitz, Christian; Zeller, Michael; Zeman, Martin; Zemla, Andrzej; Zendler, Carolin; Zenin, Oleg; Ženiš, Tibor; Zinonos, Zinonas; Zenz, Seth; Zerwas, Dirk; Zevi della Porta, Giovanni; Zhan, Zhichao; Zhang, Dongliang; Zhang, Huaqiao; Zhang, Jinlong; Zhang, Xueyao; Zhang, Zhiqing; Zhao, Long; Zhao, Tianchi; Zhao, Zhengguo; Zhemchugov, Alexey; Zheng, Shuchen; Zhong, Jiahang; Zhou, Bing; Zhou, Ning; Zhou, Yue; Zhu, Cheng Guang; Zhu, Hongbo; Zhu, Junjie; Zhu, Yingchun; Zhuang, Xuai; Zhuravlov, Vadym; Zieminska, Daria; Zimmermann, Robert; Zimmermann, Simone; Zimmermann, Stephanie; Ziolkowski, Michael; Zitoun, Robert; Živković, Lidija; Zmouchko, Viatcheslav; Zobernig, Georg; Zoccoli, Antonio; Zolnierowski, Yves; Zsenei, Andras; zur Nedden, Martin; Zutshi, Vishnu; Zwalinski, Lukasz

    2012-01-01

    Using inelastic proton-proton interactions at $\\sqrt{s}$ = 900 GeV and 7 TeV, recorded by the ATLAS detector at the LHC, measurements have been made of the correlations between forward and backward charged-particle multiplicities and, for the first time, between forward and backward charged-particle summed transverse momentum. In addition, jet-like structure in the events is studied by means of azimuthal distributions of charged particles relative to the charged particle with highest transverse momentum in a selected kinematic region of the event. The results are compared with predictions from tunes of the PYTHIA and HERWIG++ Monte Carlo generators, which in most cases are found to provide a reasonable description of the data.

  7. Particle size distribution, chemical composition and meteorological factor analysis: A case study during wintertime snow cover in Zhengzhou, China

    Science.gov (United States)

    Yu, Fei; Wang, Qun; Yan, Qishe; Jiang, Nan; Wei, Junhua; Wei, Zhiyuan; Yin, Shasha

    2018-04-01

    There was a significant snowfall event in North China from November 23 to 25 in 2015. Considering that most of the bare surface and road dust were covered by snow, the effect of dust and soil could be ignored. Atmospheric particle samples were collected in Zhengzhou, China during a haze event from November 28 to December 4, 2015. To better understand the formation and evolution of this hazy event, the size distribution, particle number, composition of particles and meteorological parameters were measured and analyzed. Results show that the meteorological conditions played an important role in the occurrence and elimination of this event. The hourly fine particle matter (PM2.5) concentration was positively correlated with relative humidity (r = 0.84, p pollutant control measures for primary emission (dust) and secondary aerosol gaseous precursor (NH3, NO2 and SO2).

  8. RETRACTED: The influence of sand diameter and wind velocity on sand particle lift-off and incident angles in the windblown sand flux

    Science.gov (United States)

    Bo, Tian-Li; Zheng, Xiao-Jing; Duan, Shao-Zhen; Liang, Yi-Rui

    2013-05-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal. This article has been retracted at the request of the Editors-in-Chief. This article also contains significant similarity with parts of text, written by the same author(s), that have appeared in Tian-Li Bo, Xiao-Jing Zheng, Shao-Zhen Duan, Yi-Rui Liang, The influence of wind velocity and sand grain diameter on the falling velocities of sand particles, Powder Technology, Volume 241, June 2013, Pages 158-165. Tian-Li Bo, Xiao-Jing Zheng, Shao-Zhen Duan, Yi-Rui Liang, Analysis of sand particles' lift-off and incident velocities in wind-blown sand flux, Acta Mechanica Sinica, April 2013, Volume 29, Issue 2, pp 158-165. Tian-Li Bo, Xiao-Jing Zheng, Shao-Zhen Duan, Yi-Rui Liang, Influence of sand grain diameter and wind velocity on lift-off velocities of sand particles, The European Physical Journal E, May 2013, 36:50. Tian-Li Bo, Shao-Zhen Duan, Xiao-Jing Zheng, Yi-Rui Liang, The influence of sand bed temperature on lift-off and falling parameters in windblown sand flux, Geomorphology, Volume 204, 1 January 2014, Pages 477-484. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

  9. Impact of spherical inclusion mean chord length and radius distribution on three-dimensional binary stochastic medium particle transport

    International Nuclear Information Syste