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Sample records for invisible particle emission

  1. Spontaneous emission and the operation of invisibility cloaks: Can the invisibility cloaks render objects invisible in quantum mechanic domain?

    CERN Document Server

    Behbahani, Mina Morshed; Mahdifar, Ali

    2016-01-01

    As a probe to explore the ability of invisibility cloaks to conceal objects in the quantum mechanics domain, we study the spontaneous emission rate of an excited two-level atom in the vicinity of an ideal invisibility cloaking. On this base, first, a canonical quantization scheme is presented for the electromagnetic field interacting with atomic systems in an anisotropic, inhomogeneous and absorbing magnetodielectric medium which can suitably be used for studying the influence of arbitrary invisibility cloak on the atomic radiative properties. The time dependence of the atomic subsystem is obtained in the Schrodinger picture. By introducing a modified set of the spherical wave vector functions, the Green tensor of the system is calculated via the continuous and discrete methods. In this formalism, the decay rate and as well the emission pattern of the aforementioned atom are computed analytically for both weak and strong coupling interaction, and then numerically calculations are done to demonstrate the perfo...

  2. Probing resonance decays to two visible and multiple invisible particles

    CERN Document Server

    Cho, Won Sang; Matchev, Konstantin T.; Park, Myeonghun

    2014-01-01

    We consider the decay of a generic resonance to two visible particles and any number of invisible particles. We show that the shape of the invariant mass distribution of the two visible particles is sensitive to both the mass spectrum of the new particles, as well as the decay topology. We provide the analytical formulas describing the invariant mass shapes for the nine simplest topologies (with up to two invisible particles in the final state). Any such distribution can be simply categorized by its endpoint, peak location and curvature, which are typically sufficient to discriminate among the competing topologies. In each case, we list the effective mass parameters which can be measured by experiment. In certain cases, the invariant mass shape is sufficient to completely determine the new particle mass spectrum, including the overall mass scale.

  3. Spontaneous emission and the operation of invisibility cloaks

    Science.gov (United States)

    Morshed Behbahani, Mina; Amooghorban, Ehsan; Mahdifar, Ali

    2016-07-01

    As a probe to explore the ability of invisibility cloaks to conceal objects in the quantum mechanics domain, we study the spontaneous emission rate of an excited two-level atom in the vicinity of an ideal invisibility cloaking. On this base, first, a canonical quantization scheme is presented for the electromagnetic field interacting with atomic systems in an anisotropic, inhomogeneous, and absorbing magnetodielectric medium which can suitably be used for studying the influence of arbitrary invisibility cloak on the atomic radiative properties. The time dependence of the atomic subsystem is obtained in the Schrodinger picture. By introducing a modified set of the spherical wave-vector functions, the Green tensor of the system is calculated via exact and discrete methods. In this formalism, the decay rate and as well the emission pattern of the aforementioned atom are computed analytically for both weak and strong coupling interaction, and then numerically calculations are done to demonstrate the performances of cloaking in the quantum mechanics domain. Special attention is paid to different possible orientations and locations of the atomic system near the spherical invisibility cloaking. Results in the presence and the absence of the invisibility cloak are compared. We find that the cloak works very well far from its resonance frequency to conceal a macroscopic object, whereas at near the resonance frequency the object is more visible than the situation where the object is not covered by the cloak.

  4. Discovery Mondays - 'Particle tracks: Seeing the invisible'

    CERN Multimedia

    2007-01-01

    Simulation of particle tracks in the CMS detector. How can you 'see' something as infinitesimal and fleeting as an elementary particle that defeats even the most powerful microscope? Well, physicists have detectors to snoop on them. Unlike biologists looking at bacteria, physicists don't see the particles themselves. They study their impact on sensitive materials as they pass through them at ultra high speed, a bit like seeing plane vapour trails in a clear sky. At the next Discovery Monday you will be able to find out about the different methods used at CERN to detect particles. There will be demonstrations of the cloud chamber, where particles leave tell-tale evidence of their passage in tracks of droplets. You will also learn about past and current particle track detection techniques and how the tracks are reconstructed into magnificent composite images. Don't miss this opportunity to learn about the various ways of 'seeing' particles. The event will be conducted in French. Come along to the Microcosm ...

  5. Seeing an invisible axion in the supersymmetric particle spectrum.

    Science.gov (United States)

    Conlon, Joseph P

    2006-12-31

    I describe how under favorable circumstances, the existence of an invisible axion could correlate with a distinctive CERN Large Hadron Collider sparticle spectrum, in particular, through a gluino approximately ln(M(P)/m(3/2)) times heavier than other gauginos.

  6. Search for the production of Higgs boson in association with invisible particles, in the ATLAS detector

    CERN Document Server

    Hard, Andrew; The ATLAS collaboration

    2016-01-01

    Some theories predict the production of Higgs bosons in association with invisible particles. The signature of such events would be a Higgs boson associated to a large missing transverse energy. Such events are searched for in different decay modes of the Higgs boson, using about 10 fb-1 of p-p collisions at 13 TeV.

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

    Science.gov (United States)

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

    2017-03-28

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

  8. An Instrument to Measure Aircraft Sulfate Particle Emissions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aircraft particle emissions contribute a modest, but growing, portion of the overall particle emissions budget. Characterizing aircraft particle emissions is...

  9. Particle Emissions from Biomass Combustion

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-05-01

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

  10. Invisible matter.

    Science.gov (United States)

    Dolgov, A. D.

    These lectures have been given to particle physicists, mostly experimentalists and very briefly and at a pedestrian level review the problems of dark matter. The content of the lectures is the following: 1. Introduction. 2. Cosmological background. 3. Luminous matter. 4. Primordial nucleosynthesis and the total amount of baryons. 5. Gravitating invisible matter. 6. Baryonic crisis. 7. Inflationary omega. 8. Intermediate summary. 9. Possible forms of dark matter. 10. Structure formation: basic assumptions. 11. Structure formations: basics of the theory. 12. Evolution of perturbations with different forms of dark matter. 13. Conclusion. The presentation and conclusion reflect personal view of the author that a considerable amount of invisible energy in the universe is in the form of vacuum energy (cosmological constant) and possibly in the form of a classical field which adjusts vacuum energy to the value permitted and requested by astronomical data.

  11. Mass limits of invisibly decaying Higgs particles from the LEP data

    CERN Document Server

    Brahmachari, B; Rindani, S D; Roy, D P; Sridhar, K; Brahmachari, Biswajoy; Joshipura, Anjan S.; Rindani, Saurabh D.; K, Sridhar

    1993-01-01

    In the Majoron models the $SU(2)$ doublet Higgs can decay invisibly into a Majoron pair via its mixing with a singlet. An analysis of the LEP data shows the invisible decay mode to be more visible than the SM decay. For these models, the dominantly doublet Higgs $H$ is shown to have a mass limit within $\\pm 6$ GeV of the SM limit irrespective of the model parameters. But the dominantly singlet one $S$ can be arbitrarily light for sufficiently small mixing angle.

  12. Continental anthropogenic primary particle number emissions

    Science.gov (United States)

    Paasonen, Pauli; Kupiainen, Kaarle; Klimont, Zbigniew; Visschedijk, Antoon; Denier van der Gon, Hugo A. C.; Amann, Markus

    2016-06-01

    Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas-Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol-cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening

  13. Sharpening m{sub T2} cusps. The mass determination of semi-invisibly decaying particles from a resonance

    Energy Technology Data Exchange (ETDEWEB)

    Harland-Lang, Lucian A. [Durham Univ. (United Kingdom). Dept. of Physics; Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Kom, Chun-Hay [Liverpool Univ. (United Kingdom). Dept. of Mathematical Sciences; Sakurai, Kazuki [King' s College London (United Kingdom). Theoretical Particle Physics and Cosmology Group; Tonini, Marco [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-12-15

    We revisit mass determination techniques for the minimum symmetric event topology, namely X pair production followed by X{yields}lN, where X and N are unknown particles with the masses to be measured, and N is an invisible particle. We consider separate scenarios, with different initial constraints on the invisible particle momenta, and present a systematic method to identify the kinematically allowed mass regions in the (m{sub N},m{sub X}) plane. These allowed regions exhibit a cusp structure at the true mass point, which is equivalent to the one observed in the m{sub T2} endpoints in certain cases. By considering the boundary of the allowed mass region we systematically define kinematical variables which can be used in measuring the unknown masses, and find a new expression for the m{sub T2} variable as well as its inverse. We explicitly apply our method to the case that X is pair produced from a resonance, and as a case study, we consider the process pp {yields} A {yields} {chi}{sup +}{sub 1}{chi}{sup -}{sub 1}, followed by {chi}{sup {+-}}{sub 1} {yields} l{nu}, in the minimal supersymmetric standard model and show that our method provides a precise measurement of the chargino and sneutrino masses, m{sub X} and m{sub N}, at 14 TeV LHC with 300 fb{sup -1} luminosity.

  14. Particle Emissions from Domestic Gas Cookers

    DEFF Research Database (Denmark)

    Glarborg, Peter; Livbjerg, Hans; Wagner, Ayten Yilmaz

    2010-01-01

    The authors experimentally studied the formation of submicron particles from a domestic gas cooker in a compartment free from external particle sources. The effects of fuel (methane, natural gas, odorant-free natural gas), primary aeration, flow rate, and fuel sulphur content on particle emissions...... were investigated. The experiments confirmed reports from literature that blue burning flames of domestic gas cookers emit submicron particles. The particle number concentrations varied in the range 103-106 particles/cm3, depending on the fuel, flow rate, and primary air addition. The diameters...

  15. Fine particle emissions from residential wood combustion

    Energy Technology Data Exchange (ETDEWEB)

    Tissari, J.

    2008-07-01

    Residential wood combustion (RWC) appliances have the high probability of incomplete combustion, producing e.g. fine particles and hazardous organic compounds. In this thesis, the fine particle number and mass emissions, particle composition and morphology, and gas emissions were investigated from the modern (MMH) and conventional masonry heaters (CMH), sauna stoves (SS) and pellet burner. The investigation was based on laboratory and field experiments applying extensive and unique particle sampling methods. The appliance type, fuel and operational practices were found to affect clearly the fine particle emissions. In good combustion conditions (e.g. in pellet combustion), the fine particle mass (PM{sub 1}) emission factors were low, typically below 0.3 g kg-1, and over 90% of the PM{sub 1} consisted of inorganic compounds (i.e fine ash). From the CMH the typical PM{sub 1} values were 1.6-1.8 g kg-1, and from the SS 2.7-5.0 g kg-1, but were strongly dependent on operational practices. The smouldering combustion in CMH increased PM{sub 1} emission up to 10 g kg-1. The good secondary combustion in the MMH reduced the particle organic matter (POM) and gaseous emissions, but not substantially the elemental carbon (EC, i.e. soot) emission, and the typical PM{sub 1} values were 0.7-0.8 g kg-1. The particle number emissions were high, and did not correspond with the completition of combustion. The particle number distributions were mainly dominated by ultrafine (<100 nm) particles, but varied dependent on combustion conditions. The electronmicroscopy analyses showed that ultrafine particles were composed mainly of K, S and Zn. From the smouldering combustion, particles were composed mainly of carbon compounds and they had a closed sinteredlike structure, due to organic matter on the particles. Controlling the gasification rate via the primary air supply, log and batch size, as well as fuel moisture content, is important for the reduction of emissions in batch combustion

  16. Particle emissions from biomass combustion

    Science.gov (United States)

    Chabadová, Jana; Papučík, Štefan; Nosek, Radovan

    2014-08-01

    The paper presents an analysis of the impact of fuel feed to power and emissions parameters of the automatic domestic boiler for combustion of wood pellets. For the analysis has been proposed an experimental methodology of boiler measuring. The investigated boiler is designed for operation in domestic heating system. It has heat power equal to 18 kW. Concentrations of flue gas species were registered at the exit the boiler and based on the measured parameters was carried out evaluation of the impact of the fuel feed to heat power and production of emissions.

  17. Mechanically Invisible Polymer Coatings

    DEFF Research Database (Denmark)

    2014-01-01

    phase comprises particles, said particles comprising a filler material and an encapsulating coating of a second polymeric material, wherein the backbones of the first and second polymeric materials are the same. The composition may be used in electroactive polymers (EAPs) in order to obtain mechanically...... invisible polymer coatings....

  18. Signatures de l'invisible

    CERN Multimedia

    CERN Press Office. Geneva

    2000-01-01

    "Signatures of the Invisible" is an unique collaboration between contemporary artists and contemporary physicists which has the potential to help redefine the relationship between science and art. "Signatures of the Invisible" is jointly organised by the London Institute - the world's largest college of art and design and CERN*, the world's leading particle physics laboratory. 12 leading visual artists:

  19. Search for production of heavy particles decaying to top quarks and invisible particles in pp collisions at √s = 1.96  TeV.

    Science.gov (United States)

    Aaltonen, T; Álvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Apresyan, A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bauer, G; Bedeschi, F; Beecher, D; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Brisuda, A; Bromberg, C; Brucken, E; Bucciantonio, M; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Calancha, C; Camarda, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Chung, W H; Chung, Y S; Ciobanu, C I; Ciocci, M A; Clark, A; Compostella, G; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Dagenhart, D; d'Ascenzo, N; Datta, M; de Barbaro, P; De Cecco, S; De Lorenzo, G; Dell'Orso, M; Deluca, C; Demortier, L; Deng, J; Deninno, M; Devoto, F; d'Errico, M; Di Canto, A; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Dorigo, M; Dorigo, T; Ebina, K; Elagin, A; Eppig, A; Erbacher, R; Errede, D; Errede, S; Ershaidat, N; Eusebi, R; Fang, H C; Farrington, S; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Funakoshi, Y; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, S R; Halkiadakis, E; Hamaguchi, A; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harr, R F; Hatakeyama, K; Hays, C; Heck, M; Heinrich, J; Herndon, M; Hewamanage, S; Hidas, D; Hocker, A; Hopkins, W; Horn, D; Hou, S; Hughes, R E; Hurwitz, M; Husemann, U; Hussain, N; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jha, M K; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Ketchum, W; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, H W; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirby, M; Klimenko, S; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Krumnack, N; Kruse, M; Krutelyov, V; Kuhr, T; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; LeCompte, T; Lee, E; Lee, H S; Lee, J S; Lee, S W; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lin, C-J; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, Q; Liu, T; Lockwitz, S; Lockyer, N S; Loginov, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maeshima, K; Makhoul, K; Maksimovic, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Martínez, M; Martínez-Ballarín, R; Mastrandrea, P; Mathis, M; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzione, A; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Mondragon, M N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Movilla Fernandez, P; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norniella, O; Nurse, E; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Potamianos, K; Poukhov, O; Prokoshin, F; Pronko, A; Ptohos, F; Pueschel, E; Punzi, G; Pursley, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Rao, K; Redondo, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rubbo, F; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Sakurai, Y; Santi, L; Sartori, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schmidt, M P; Schmitt, M

    2011-05-13

    We present a search for a new particle T' decaying to top quark via T' → t + X, where X is an invisible particle. In a data sample with 4.8  fb(-1) of integrated luminosity collected by the CDF II detector at Fermilab in pp collisions with √s = 1.96  TeV, we search for pair production of T' in the lepton + jets channel, pp → tt + X + X → ℓνbqq'b + X + X. We interpret our results primarily in terms of a model where T' are exotic fourth generation quarks and X are dark matter particles. Current direct and indirect bounds on such exotic quarks restrict their masses to be between 300 and 600  GeV/c2, the dark matter particle mass being anywhere below m(T'). The data are consistent with standard model expectations, and we set 95% confidence level limits on the generic production of T'T' → tt + X + X. For the dark matter model we exclude T' at 95% confidence level up to m(T') = 360  GeV/c2 for m(X) ≤ 100  GeV/c2.

  20. Measuring soot particles from automotive exhaust emissions

    Science.gov (United States)

    Andres, Hanspeter; Lüönd, Felix; Schlatter, Jürg; Auderset, Kevin; Jordan-Gerkens, Anke; Nowak, Andreas; Ebert, Volker; Buhr, Egbert; Klein, Tobias; Tuch, Thomas; Wiedensohler, Alfred; Mamakos, Athanasios; Riccobono, Francesco; Discher, Kai; Högström, Richard; Yli-Ojanperä, Jaakko; Quincey, Paul

    2014-08-01

    The European Metrology Research Programme participating countries and the European Union jointly fund a three year project to address the need of the automotive industry for a metrological sound base for exhaust measurements. The collaborative work on particle emissions involves five European National Metrology Institutes, the Tampere University of Technology, the Joint Research Centre for Energy and Transport and the Leibniz Institute for Tropospheric Research. On one hand, a particle number and size standard for soot particles is aimed for. Eventually this will allow the partners to provide accurate and comparable calibrations of measurement instruments for the type approval of Euro 5b and Euro 6 vehicles. Calibration aerosols of combustion particles, silver and graphite proof partially suitable. Yet, a consensus choice together with instrument manufactures is pending as the aerosol choice considerably affects the number concentration measurement. Furthermore, the consortium issued consistent requirements for novel measuring instruments foreseen to replace today's opacimeters in regulatory periodic emission controls of soot and compared them with European legislative requirements. Four partners are conducting a metrological validation of prototype measurement instruments. The novel instruments base on light scattering, electrical, ionisation chamber and diffusion charging sensors and will be tested at low and high particle concentrations. Results shall allow manufacturers to further improve their instruments to comply with legal requirements.

  1. Measuring soot particles from automotive exhaust emissions

    Directory of Open Access Journals (Sweden)

    Andres Hanspeter

    2014-01-01

    Full Text Available The European Metrology Research Programme participating countries and the European Union jointly fund a three year project to address the need of the automotive industry for a metrological sound base for exhaust measurements. The collaborative work on particle emissions involves five European National Metrology Institutes, the Tampere University of Technology, the Joint Research Centre for Energy and Transport and the Leibniz Institute for Tropospheric Research. On one hand, a particle number and size standard for soot particles is aimed for. Eventually this will allow the partners to provide accurate and comparable calibrations of measurement instruments for the type approval of Euro 5b and Euro 6 vehicles. Calibration aerosols of combustion particles, silver and graphite proof partially suitable. Yet, a consensus choice together with instrument manufactures is pending as the aerosol choice considerably affects the number concentration measurement. Furthermore, the consortium issued consistent requirements for novel measuring instruments foreseen to replace today’s opacimeters in regulatory periodic emission controls of soot and compared them with European legislative requirements. Four partners are conducting a metrological validation of prototype measurement instruments. The novel instruments base on light scattering, electrical, ionisation chamber and diffusion charging sensors and will be tested at low and high particle concentrations. Results shall allow manufacturers to further improve their instruments to comply with legal requirements.

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

    CERN Document Server

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

    2016-01-01

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

  3. Invisibility Studies

    DEFF Research Database (Denmark)

    Invisibility Studies explores current changes in the relationship between what we consider visible and what invisible in different areas of contemporary culture. Contributions trace how these changes make their marks on various cultural fields and investigate the cultural significance of these de...... this conversation by bringing together scholars across the fields of architectural history and theory, art, film and literature, philosophy, cultural theory and contemporary anthropology as well as featuring work by a collective of artists.......Invisibility Studies explores current changes in the relationship between what we consider visible and what invisible in different areas of contemporary culture. Contributions trace how these changes make their marks on various cultural fields and investigate the cultural significance...

  4. Characterizing Invisible Electroweak Particles through Single-Photon Processes at High Energy $e^+e^-$ Colliders

    CERN Document Server

    Choi, Seong Youl; Kalinowski, Jan; Rolbiecki, Krzysztof; Wang, Xing

    2015-01-01

    We explore the scenarios where the only accessible new states at the electroweak scale consist of a pair of color-singlet electroweak particles, whose masses are degenerate at the tree level and split only by electroweak symmetry breaking at the loop level. For the sake of illustration, we consider a supersymmetric model and study the following three representative cases with the lower-lying states as (a) two spin-1/2 Higgsino SU(2)$_L$ doublets, (b) a spin-1/2 wino SU(2)$_L$ triplet and (c) a spin-0 left-handed slepton SU(2)$_L$ doublet. Due to the mass-degeneracy, those lower-lying electroweak states are difficult to observe at the LHC and rather challenging to detect at the $e^+ e^-$ collider as well. We exploit the pair production in association with a hard photon radiation in high energy $e^+ e^-$ collisions. If kinematically accessible, such single-photon processes at $e^+e^-$ colliders with polarized beams enable us to characterize each scenario by measuring the energy and scattering angle of the assoc...

  5. Energetic particle emission: preequilibrium emission and cooperative effects

    Energy Technology Data Exchange (ETDEWEB)

    Sapienza, P.; Coniglione, R.; Colonna, M.; Migneco, E.; Agodi, C.; Alba, R.; Bellia, G.; Zoppo, A. Del; Finocchiaro, P.; Greco, V.; Loukachine, K.; Maiolino, C.; Piattelli, P.; Santonocito, D. [INFN Lab. Nazionale del Sud, Via A. Doria 44, Catania (Italy); Colonna, N. [INFN, Bari (Italy); Bruno, M.; D Agostino, M.; Mastinu, P.F. [INFN and Dipartimento di Fisica, Bologna (Italy); Gramegna, F. [INFN Laboratorio Nazionale di Legnaro, Padova (Italy); Iori, I.; Fabbietti, L.; Moroni, A. [INFN and Dipartimento di Fisica, Milano (Italy); Margagliotti, G.V.; Milazzo, P.M.; Rui, R.; Vannini, G. [INFN and Dipartimento di Fisica, Trieste (Italy); Blumenfeld, Y.; Scarpaci, J.A. [Institut de Physique Nucleaire, IN2P3CNRS, F91406 Orsay (France)

    2001-09-01

    Full text: The {sup 58} Ni +{sup 58} Ni reaction at 30 A MeV was investigated at Laboratori Nazionale del Sud with the MEDEA and MULTICS apparatus. Energetic protons were detected in coincidence with photons, light charged particles (Z = 1, 2) (LCP) and intermediate and heavy fragments on an event by event basis. Protons with energy extending up to almost 20% of the total available energy, namely much larger than expected by coupling the relative motion with a sharp nucleon Fermi momentum distribution (kinematical limit), were measured in our experiment. We have also investigated the average proton multiplicity as a function of the number of participating nucleons A{sub part} (b) and a striking behavior with increasing energy is found. Indeed, the experimental proton multiplicity (full squares) displays the expected linear dependence on A{sub part} (b) for energy close to the kinematical limit (60 {<=} Ep {<=} 80 MeV), while the multiplicity of extremely energetic protons (130 {<=} Ep {<=} 150 MeV) exhibits an almost quadratic increase with A{sub part}. The comparison with BNV calculations which include the momentum dependence in the effective potential shows that the features of the energetic proton emission are well reproduced up to {approx_equal} 110 MeV while this approach fails to explain the almost quadratic dependence on the number of participant nucleons of the yield of very energetic protons (E{sub p}{sup NN} {>=} 130 MeV). So, the observed behavior calls for the introduction of mechanisms beyond the mean field and two body nucleon-nucleon collisions such as cooperative effects. In conclusions, these results shed some light on the emission of extremely energetic protons and can improve the understanding of the mechanism responsible for deep subthreshold particle production. Moreover, the detailed comparison with dynamical calculations allows to get a deeper insight on the first non equilibrated stage of the reaction where the highest temperatures and

  6. Secondary particle emission from sapphire single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Minnebaev, K.F., E-mail: minnebaev@mail.ru [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Khvostov, V.V.; Zykova, E.Yu.; Tolpin, K.A. [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Colligon, J.S. [Manchester Metropolitan University, Chester Street, Manchester M1 5GD (United Kingdom); Yurasova, V.E. [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation)

    2015-07-01

    Secondary ion emission from sapphire single crystal has been studied experimentally and by means of computer simulation. The particular oscillations of secondary ion energy spectra and two specific maxima of O{sup +} and Al{sup +} ions were observed under irradiation of (0001) sapphire face by 1 and 10 keV Ar{sup +} ions. We have explained this by the interplay of the charge exchange processes between moving particles and solids. The existence of two maxima in energy spectra of O{sup +} and Al{sup +} secondary ions can be also connected with special features of single-crystal sputtering: the low-energy peak can be formed by random sputtering and the high-energy peak from focusing collisions. In addition some similarity was found between the positions of low-energy maximum in energy spectra of Al{sup +} ions emitted from sapphire and the principal maxima of Al{sup +} ions ejected from the aluminum single crystal. This indicates a possibility to explain the presence of low-energy maximum in energy spectra of secondary ions ejecting from sapphire by emission of Al{sup +} ions from aluminum islands appearing in a number of cases on the sapphire surface due to preferential sputtering of oxygen. These different mechanisms of creating the energy spectra of ions emitted from sapphire should be taken in account.

  7. Atmospheric and environmental impacts of volcanic ash particle emissions

    Science.gov (United States)

    Durant, Adam

    2010-05-01

    Globally, at any one time, there may be 20 volcanoes erupting that collectively emit a constant flux of gases and aerosol, including silicate particles (tephra), to the atmosphere which influences processes including cloud microphysics, heterogeneous chemistry and radiative balance. The nature and impact of atmospheric volcanic particle fluxes depend on total mass erupted, emission rate, emission source location, physical and chemical properties of the particles, and the location and residence time of the particles in the atmosphere. Removal of ash particles from the atmosphere through sedimentation is strongly influenced by particle aggregation through hydrometeor formation, and convective instabilities such as mammatus. I will address the following questions: What are the atmospheric impacts of volcanic ash emissions? What controls the residence time of volcanic particles in the atmosphere? What affects particle accumulation at the surface? And what are the human and environmental impacts of ash fallout?

  8. Silicon Array for Multi-particle Emission

    Institute of Scientific and Technical Information of China (English)

    XU; Xin-xing; LIN; Cheng-jian; SUN; Li-jie; BAO; Peng-fei; YANG; Lei; YANG; Feng; ZHANG; Huan-qiao; LIU; Zu-hua; JIA; Hui-ming; MA; Nan-ru

    2013-01-01

    Remarkable progress in the study of two-proton emission has been made in recent years.One of the next destinations is the realization of high-precision direct measurements of decay-energy and emission-angle correlations inβ-delayed two-proton(β2p)emission.We have studiedβ2p correlated emission of the ground state of 26P at the proton drip line with the direct measurement at the National

  9. Study the effect of beam energy spread and detector resolution on the search for Higgs boson decays to invisible particles at a future e$^+$e$^-$ circular collider

    CERN Document Server

    Cerri, Olmo; Pierini, Maurizio; Podo, Alessandro; Rolandi, Gigi

    2016-01-01

    We study the expected sensitivity to measure the branching ratio of Higgs boson decays to invisible particles at a future circular \\epem collider (FCCee), considering an integrated luminosity of 3.5 ab$^{-1}$ at a center-of-mass energy $\\sqrt{s}=240$ GeV. The impact of the energy spread of the FCCee beam on the measurement is discussed. Two different detector concepts are considered: a detector corresponding to the CMS reconstruction performances and the expected design of the ILC detector. The minimum branching ratio for a $5\\sigma$ observation after 3.5ab$^{-1}$ of data taking is $1.7\\pm 0.1\\%(stat+syst) $ ($2.5\\pm 0.3\\%((stat+syst))$ ) for an ILC-like (CMS-like) detector concept. The branching ratio exclusion limit at 95\\% CL is $0.63 \\pm 0.22\\%((stat+syst))$ ($0.92\\pm0.32 \\%((stat+syst))$).

  10. Search for a massive invisible particle $X^0$ in $B^{+}\\to e^{+}X^{0}$ and $B^{+}\\to \\mu^{+}X^{0}$ decays

    CERN Document Server

    Park, C -S; Adachi, I; Aihara, H; Asner, D M; Aushev, T; Babu, V; Badhrees, I; Bakich, A M; Barberio, E; Behera, P; Bhardwaj, V; Biswal, J; Bonvicini, G; Bozek, A; Bračko, M; Browder, T E; Červenkov, D; Chekelian, V; Chen, A; Cheon, B G; Chilikin, K; Chistov, R; Cho, K; Chobanova, V; Choi, Y; Cinabro, D; Dalseno, J; Danilov, M; Dash, N; Doležal, Z; Dutta, D; Eidelman, S; Farhat, H; Fast, J E; Ferber, T; Fulsom, B G; Gaur, V; Gabyshev, N; Garmash, A; Gillard, R; Goh, Y M; Goldenzweig, P; Grzymkowska, O; Hara, T; Hayasaka, K; Hayashii, H; Heck, M; Hou, W -S; Iijima, T; Inami, K; Inguglia, G; Ishikawa, A; Itoh, R; Iwasaki, Y; Jaegle, I; Jeon, H B; Julius, T; Kang, K H; Kato, E; Katrenko, P; Kim, D Y; Kim, J B; Kim, K T; Kim, M J; Kim, S H; Kinoshita, K; Kodys, P; Korpar, S; Križan, P; Krokovny, P; Kuzmin, A; Lee, I S; Li, C H; Li, L; Li, Y; Gioi, L Li; Libby, J; Liventsev, D; Lubej, M; Lukin, P; Masuda, M; Matvienko, D; Miyabayashi, K; Miyata, H; Mizuk, R; Mohanty, G B; Mohanty, S; Moll, A; Moon, H K; Mussa, R; Nakano, E; Nakao, M; Nath, K J; Nayak, M; Negishi, K; Nisar, N K; Nishida, S; Ogawa, S; Okuno, S; Pakhlov, P; Pakhlova, G; Pal, B; Park, C W; Park, H; Pedlar, T K; Petrič, M; Piilonen, L E; Pulvermacher, C; Purohit, M V; Rauch, J; Ritter, M; Rostomyan, A; Ryu, S; Sakai, Y; Sandilya, S; Santelj, L; Sanuki, T; Sato, Y; Schlüter, T; Schneider, O; Schnell, G; Schwanda, C; Schwartz, A J; Seino, Y; Semmler, D; Senyo, K; Seon, O; Sevior, M E; Shebalin, V; Shen, C P; Shibata, T -A; Shiu, J -G; Shwartz, B; Simon, F; Sokolov, A; Stanič, S; Starič, M; Stypula, J; Sumiyoshi, T; Tamponi, U; Teramoto, Y; Trabelsi, K; Uchida, M; Uglov, T; Unno, Y; Uno, S; Urquijo, P; Usov, Y; Van Hulse, C; Vanhoefer, P; Varner, G; Varvell, K E; Wagner, M N; Wang, C H; Wang, M -Z; Wang, P; Watanabe, Y; Won, E; Yamaoka, J; Yashchenko, S; Ye, H; Yook, Y; Yusa, Y; Zhang, Z P; Zhilich, V; Zhulanov, V; Zupanc, A

    2016-01-01

    We present a search for a non-Standard-Model invisible particle $X^0$ in the mass range $0.1\\textrm{-}1.8 \\,{\\rm GeV}/{c^2}$ in $B^{+}\\to e^{+} X^{0}$ and $B^{+}\\to \\mu^{+} X^{0}$ decays. The results are obtained from a $711~{\\rm fb}^{-1}$ data sample that corresponds to $772 \\times 10^{6} B\\bar{B}$ pairs, collected at the $\\Upsilon(4S)$ resonance with the Belle detector at the KEKB $e^+ e^-$ collider. One $B$ meson is fully reconstructed in a hadronic mode to determine the momentum of the lepton of the signal decay in the rest frame of the recoiling partner $B$ meson. We find no evidence of a signal and set upper limits on the order of $10^{-6}$.

  11. Study the effect of beam energy spread and detector resolution on the search for Higgs boson decays to invisible particles at a future e$^+$e$^-$ circular collider

    CERN Document Server

    Cerri, Olmo; Pierini, Maurizio; Podo, Alessandro; Rolandi, Gigi

    2017-01-01

    We study the expected sensitivity to measure the branching ratio of Higgs boson decays to invisible particles at a future circular \\epem collider (FCCee), considering an integrated luminosity of 3.5 ab$^{-1}$ at a center-of-mass energy $\\sqrt{s}=240$ GeV. The impact of the energy spread of the FCCee beam on the measurement is discussed. Two different detector concepts are considered: a detector corresponding to the CMS reconstruction performances and the expected design of the ILC detector. The minimum branching ratio for a $5\\sigma$ observation after 3.5ab$^{-1}$ of data taking is $1.7\\pm 0.1\\%(stat+syst) $ ($2.5\\pm 0.3\\%((stat+syst))$ ) for an ILC-like (CMS-like) detector concept. The branching ratio exclusion limit at 95\\% CL is $0.63 \\pm 0.22\\%((stat+syst))$ ($0.92\\pm0.32 \\%((stat+syst))$).

  12. Invisible Engineers

    Science.gov (United States)

    Ohashi, Hideo

    Questionnaire to ask “mention three names of scientists you know” and “three names of engineers you know” was conducted and the answers from 140 adults were analyzed. The results indicated that the image of scientists is represented by Nobel laureates and that of engineers by great inventors like Thomas Edison and industry founders like Soichiro Honda. In order to reveal the image of engineers among young generation, questionnaire was conducted for pupils in middle and high schools. Answers from 1,230 pupils were analyzed and 226 names mentioned as engineers were classified. White votes reached 60%. Engineers who are neither big inventors nor company founders collected less than 1% of named votes. Engineers are astonishingly invisible from young generation. Countermeasures are proposed.

  13. A novel clustering approach to positron emission particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, Cody, E-mail: cwiggin2@vols.utk.edu [University of Tennessee-Knoxville, Department of Physics and Astronomy, 1408 Circle Drive, Knoxville, TN 37996 (United States); Santos, Roque; Ruggles, Arthur [University of Tennessee-Knoxville, Department of Nuclear Engineering (United States)

    2016-03-01

    A novel approach to positron emission particle tracking is presented based on determining regions of space with high density of line of response crossing via clustering. The method is shown to be able to accurately track multiple particles in systems where the number of particles is unknown and in which particles can enter and leave the field of view of the scanning system. This method is explored in various environments and its parametric dependence is studied. - Highlights: • A new approach to positron emission particle tracking is presented. • Using G-means clustering, multiple particle tracking is enabled. • Multiple and variable number particle tracking is explored. • Parametric dependence of algorithm is studied.

  14. Minimum ionizing particle detection by secondary electron emission

    Energy Technology Data Exchange (ETDEWEB)

    Faivre, J.C.; Fanet, H.; Garin, A.; Robert, J.P.; Rouger, M.; Saudinos, J.

    1977-02-01

    The use of secondary electron emission to detect high energy particles is investigated. Low density KCl layers have been tested to detect MeV electrons, 400-750 MeV protons and high energy deuterons. The efficiency and the secondary electron spectrum are presented. The results justify the use of low-density KCl layer to detect minimum ionizing particles.

  15. Black hole particle emission in higher-dimensional spacetimes

    CERN Document Server

    Cardoso, V; Gualtieri, L; Cardoso, Vitor; Cavaglia, Marco; Gualtieri, Leonardo

    2006-01-01

    In models with extra dimensions, a black hole evaporates both in the bulk and on the visible brane, where standard model fields live. The exact emissivities of each particle species are needed to determine how the black hole decay proceeds. We compute and discuss the absorption cross-sections, the relative emissivities and the total power output of all known fields in the evaporation phase. Graviton emissivity is highly enhanced as the spacetime dimensionality increases. Therefore, a black hole loses a significant fraction of its mass in the bulk. This result has important consequences for the phenomenology of black holes in models with extra dimensions and black hole detection in particle colliders.

  16. Measuring the invisible: quantifying the CO{sub 2} emission reductions from transport solutions in Hanoi, Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Tuan, Le Anh (Dept. of Internal Combustion Engines, Inst. of Transportation Engineering, Hanoi Univ. of Technology (Viet Nam)); Schipper, Lee (Precourt Inst. for Energy Efficiency, Stanford Univ. (United States)); Orn, Hans (CONTRANS AB (Sweden)); Ng, Wei-Shiuen (Consultant (Singapore))

    2009-07-01

    Working with local experts, the authors developed a transport emissions model for Hanoi, Vietnam, after collecting transport activity data, developing emissions factors, and assigning emissions values to past, present and future levels of passenger transport activity scenarios. A set of two scenarios were used to illustrate emissions impacts of two alternative transport policies previously outlined in the Hanoi Integrated Development and Environment Program (HAIDEP; ALMEC 2007) Master Plan. One policy emphasized improving public transport, while the other is a business-as-usual scenario with a higher automobile growth. These mutually exclusive policies were thought to represent the most probable future scenarios for the city's transport system. This study assumed changes in the demand and supply of transport services, as well as policies for investment and vehicle emission standards that have been deemed reasonable by various experts. If the government promotes public transport to a higher degree and mandates stricter fuel quality and vehicle emission standards, criteria pollutant emissions may be stabilized in 2020 at 2005 levels, while still allowing the same level of mobility. CO{sub 2} emissions from passenger transport will increase as shown in all scenarios, but less so if vehicles are less fuel intensive and the share of public transport is higher. Nevertheless, the sooner emissions mitigation measures are implemented, the lower future emissions will be. And the dominance of the two-wheeler as the main form of transport invites speculation whether this vehicle might be key to sustainable transportation in dense cities.

  17. Developing particle emission inventories using remote sensing (PEIRS).

    Science.gov (United States)

    Tang, Chia-Hsi; Coull, Brent A; Schwartz, Joel; Lyapustin, Alexei I; Di, Qian; Koutrakis, Petros

    2017-01-01

    Information regarding the magnitude and distribution of PM2.5 emissions is crucial in establishing effective PM regulations and assessing the associated risk to human health and the ecosystem. At present, emission data is obtained from measured or estimated emission factors of various source types. Collecting such information for every known source is costly and time-consuming. For this reason, emission inventories are reported periodically and unknown or smaller sources are often omitted or aggregated at large spatial scale. To address these limitations, we have developed and evaluated a novel method that uses remote sensing data to construct spatially resolved emission inventories for PM2.5. This approach enables us to account for all sources within a fixed area, which renders source classification unnecessary. We applied this method to predict emissions in the northeastern United States during the period 2002-2013 using high-resolution 1 km × 1 km aerosol optical depth (AOD). Emission estimates moderately agreed with the EPA National Emission Inventory (R(2) = 0.66-0.71, CV = 17.7-20%). Predicted emissions are found to correlate with land use parameters, suggesting that our method can capture emissions from land-use-related sources. In addition, we distinguished small-scale intra-urban variation in emissions reflecting distribution of metropolitan sources. In essence, this study demonstrates the great potential of remote sensing data to predict particle source emissions cost-effectively. We present a novel method, particle emission inventories using remote sensing (PEIRS), using remote sensing data to construct spatially resolved PM2.5 emission inventories. Both primary emissions and secondary formations are captured and predicted at a high spatial resolution of 1 km × 1 km. Using PEIRS, large and comprehensive data sets can be generated cost-effectively and can inform development of air quality regulations.

  18. Ethanol emission from loose corn silage and exposed silage particles

    Science.gov (United States)

    Hafner, Sasha D.; Montes, Felipe; Rotz, C. Alan; Mitloehner, Frank

    2010-11-01

    Silage on dairy farms has been identified as a major source of volatile organic compound (VOC) emissions. However, rates of VOC emission from silage are not accurately known. In this work, we measured ethanol (a dominant silage VOC) emission from loose corn silage and exposed corn silage particles using wind tunnel systems. Flux of ethanol was highest immediately after exposing loose silage samples to moving air (as high as 220 g m -2 h -1) and declined by as much as 76-fold over 12 h as ethanol was depleted from samples. Emission rate and cumulative 12 h emission increased with temperature, silage permeability, exposed surface area, and air velocity over silage samples. These responses suggest that VOC emission from silage on farms is sensitive to climate and management practices. Ethanol emission rates from loose silage were generally higher than previous estimates of total VOC emission rates from silage and mixed feed. For 15 cm deep loose samples, mean cumulative emission was as high as 170 g m -2 (80% of initial ethanol mass) after 12 h of exposure to an air velocity of 5 m s -1. Emission rates measured with an emission isolation flux chamber were lower than rates measured in a wind tunnel and in an open setting. Results show that the US EPA emission isolation flux chamber method is not appropriate for estimating VOC emission rates from silage in the field.

  19. Emission spectrum of the atomic chain excited by channeled particle

    CERN Document Server

    Epp, V

    2014-01-01

    Basic properties of radiation of the atomic chains excited by a channeled particle are considered. Using a very simple two-dimensional model of a crystal lattice we have shown that the main part of this radiation is generated on the frequency of oscillations of a channeled particle between the crystal planes, shifted by the Doppler effect. Spectral and angular distribution and spectral distribution of the radiation of the atomic chain excited by channeled particle were calculated. Emission spectrum of the atomic chain excited by channeled particle was plotted.

  20. Mechanisms of Increased Particle and VOC Emissions during DPF Active Regeneration and Practical Emissions Considering Regeneration.

    Science.gov (United States)

    Yamada, Hiroyuki; Inomata, Satoshi; Tanimoto, Hiroshi

    2017-02-27

    Mechanisms involved in increased particle and volatile organic compound (VOC) emissions during active and parked active regenerations of a diesel particulate filter (DPF) were investigated using heavy-duty trucks equipped with both a urea selective catalytic reduction system and a DPF (SCR + DPF) and a DPF-only. Particle emissions increased in the later part of the regeneration period but the mechanisms were different above and below 23 nm. Particles above 23 nm were emitted due to the lower filtering efficiency of the DPF because of the decreasing amount of soot trapped during regeneration. Small particles below 23 nm were thought to be mainly sulfuric acid particles produced from SO2 trapped by the catalyst, being released and oxidized during regeneration. Contrary to the particle emissions, VOCs increased in the earlier part of the regeneration period. The mean molecular weights of the VOCs increased gradually as the regeneration proceeded. To evaluate "practical emissions" in which increased emissions during the regeneration were considered, a Regeneration Correction Factor (RCF), which is the average emission during one cycle of regeneration/emission in normal operation, was adopted. The RCFs of PM and VOCs were 1.1-1.5, and those of PNs were as high as 3-140, although they were estimated from a limited number of observations.

  1. Particle Emissions from District Heating Units Operating on Solid Biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Wierzbicka, Aneta [Lund Inst. of Technology (Sweden). Div. of Ergonomics and Aerosol Technology

    2005-06-01

    With the increasing interest in the use of biofuels for heat and energy generation there is a growing concern about emissions from their combustion. It has been shown that biofuel furnaces emit relatively high quantities of particulate matter in comparison to natural gas and light fuel oil furnaces. Majority of the emitted particulates are smaller than 10 {mu}m with high contribution of fine (<2.5 {mu}m) and submicron (<1 {mu}m) particles. These fine particles tend to be the most troublesome: in ambient air they have been associated with adverse health effects. Submicron particles are difficult to capture in the available particle removal technologies. The aim of this study was to characterise particle emissions from district heating units operating on three commonly used biofuels, namely sawdust. pellets and forest residues. Boilers were of moving grate type. with the maximum thermal output between 1 and 1.5 MW. The measurements were done after multi cyclones, the only particle removal devices installed, therefore the direct emissions to ambient air were characterised. Influence of type of the fuel and operation load on particle emissions was investigated. Furthermore, collection efficiencies of electrostatic precipitator (ESP) and flue gas condenser, used particle separation devices in 6 MW unit, were investigated. It has been shown that in all cases large amounts of fuel particles containing heavy metals are being emitted to the atmosphere, even though the studied district heating units meet the current mass concentration emission limit requirements. Total number concentration of emitted particles with aerodynamic diameter smaller than 5 {mu}m ranged from 3 to 8x10{sup 7} particles/cm{sub n}{sup 3} with the slightly higher values from combustion of forest residues. Both mass and total number concentrations were dominated by submicron particles contribution. Elements determined by Particle Induced X-rays Emission (PIXE) analysis (Z>12) contributed to 21-34 % of

  2. Positron Emission Particle Tracking (PEPT) for Fluid Flow Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Langford, Seth, E-mail: utne@utk.edu [Department of Nuclear Engineering, University of Tennessee-Knoxville, 315 Pasqua Nuclear Engineering, Knoxville, TN 37996 (United States); Wiggins, Cody, E-mail: cwiggin2@vols.utk.edu [University of Tennessee-Knoxville, Department of Physics and Astronomy, 401 Nielsen Physics Building, Knoxville, TN 37996 (United States); Tenpenny, Daniel; Ruggles, Arthur [Department of Nuclear Engineering, University of Tennessee-Knoxville, 315 Pasqua Nuclear Engineering, Knoxville, TN 37996 (United States)

    2016-06-15

    Highlights: • A new method for tracking multiple particles using positron emission particle tracking (PEPT) is introduced. • PEPT measurement of flow in a rectangular channel is tested against PIV and PTV. • Further work is identified to improve performance of PEPT for flow measurement. - Abstract: Positron emission particle tracking (PEPT) is used to study the behavior of flow in a rectangular test section. A multiple-particle tracking technique (multi-PEPT) is proposed and tested using a once-through flow system and a preclinical positron emission tomography (PET) scanner. This measurement is then compared to particle image velocimetry (PIV) and high-speed particle tracking velocimetry (PTV) studies of the same test section. Uncertainties in the established flow measurement methods used to validate the PEPT performance are quantified. Mean flow velocity are compared as measured by the three methods. Minor variations are exposed in the data comparisons, and uncertainty exists due to the statistical nature of our PEPT method. Nonetheless, multi-PEPT is shown to be capable as a means of examining characteristics of a complex flow regime.

  3. Positron emission particle tracking and its application to granular media.

    Science.gov (United States)

    Parker, D J

    2017-05-01

    Positron emission particle tracking (PEPT) is a technique for tracking a single radioactively labelled particle. Accurate 3D tracking is possible even when the particle is moving at high speed inside a dense opaque system. In many cases, tracking a single particle within a granular system provides sufficient information to determine the time-averaged behaviour of the entire granular system. After a general introduction, this paper describes the detector systems (PET scanners and positron cameras) used to record PEPT data, the techniques used to label particles, and the algorithms used to process the data. This paper concentrates on the use of PEPT for studying granular systems: the focus is mainly on work at Birmingham, but reference is also made to work from other centres, and options for wider diversification are suggested.

  4. Isospin effect on pre-scission particle emission

    CERN Document Server

    Ye Wei

    2003-01-01

    The isospin effect of particle emission for fissioning isobaric sources of sup 2 sup 1 sup 2 Tl, sup 2 sup 1 sup 2 Po and sup 2 sup 1 sup 2 Fr and for isotopic sources of sup 1 sup 8 sup 9 sup , sup 2 sup 0 sup 2 sup , sup 2 sup 1 sup 2 Po are explored in the framework of the Smoluchowski equation. The multiplicity of emitted particles shows a strong dependence on the isospin of the fission sources. Similar results are also observed for light fissioning isobaric sources of sup 1 sup 1 sup 0 Tc, sup 1 sup 1 sup 0 Pd and sup 1 sup 1 sup 0 In and for isotopic sources of sup 1 sup 1 sup 0 sup , sup 1 sup 1 sup 7 sup , sup 1 sup 2 sup 4 In. This indicates that the effect of isospin on the emission of particles is independent of the size of the fissioning system. It has been found with the increase of the isospin of heavy fissioning systems, the emission of charged particles is not sensitive to the viscosity strength. In addition, an Er isotopic chain is used to study the effects of isospin on pre-scission particle...

  5. Particle Emission-dependent Timing Noise of Pulsars?

    CERN Document Server

    Liu, Xiongwei; Xu, Renxin; Qiao, Guojun

    2010-01-01

    Though pulsars spin regularly, the differences between the observed and predicted ToA (time of arrival), known as "timing noise", can still reach a few milliseconds or more. We try to understand the noise in this paper. As proposed by Xu & Qiao in 2001, both dipole radiation and particle emission would result in pulsar braking. Accordingly, possible fluctuation of particle current flow is suggested here to contribute significant ToA variation of pulsars. We find that the particle emission fluctuation could lead to timing noise which can't be eliminated in timing process, and that a longer period fluctuation would arouse a stronger noise. The simulated timing noise profile and amplitude are in accord with the observed timing behaviors on the timescale of years.

  6. Characterization of multiphoton emission from aggregated gold nano particles

    Science.gov (United States)

    Eguchi, Akira; Lu, Phat; Kim, Youngsik; Milster, Tom D.

    2016-09-01

    Although gold nanoparticles (GNPs) are promising probes for biological imaging because of their attracting optical properties and bio-friendly nature, properties of the multi-photon (MP) emission from GNP aggregates produced by a short-wave infrared (SWIR) laser have not been examined. In this paper, characterization of MP emission from aggregated 50 nm GNPs excited by a femtosecond (fs) laser at 1560 nm is discussed with respect to aggregate structures. The key technique in this work is single particle spectroscopy. A pattern matching technique is applied to correlate MP emission and SEM images, which includes an optimization processes to maximize cross correlation coefficients between a binary microscope image and a binary SEM image with respect to xy displacement, image rotation angle, and image magnification. Once optimization is completed, emission spots are matched to the SEM image, which clarifies GNP ordering and emission properties of each aggregate. Correlation results showed that GNP aggregates have stronger MP emission than single GNPs. By combining the pattern matching technique with spectroscopy, MP emission spectrum is characterized for each GNP aggregate. A broad spectrum in the visible region and near infrared (NIR) region is obtained from GNP dimers, unlike previously reported surface plasmon enhanced emission spectrum.

  7. Dirac Particles Emission from An Elliptical Black Hole

    Directory of Open Access Journals (Sweden)

    Yuant Tiandho

    2017-03-01

    Full Text Available According to the general theory of relativiy, a black hole is defined as a region of spacetime with super-strong gravitational effects and there is nothing can escape from it. So in the classical theory of relativity, it is safe to say that black hole is a "dead" thermodynamical object. However, by using quantum mechanics theory, Hawking has shown that a black hole may emit particles. In this paper, calculation of temperature of an elliptical black hole when emitting the Dirac particles was presented. By using the complexpath method, radiation can be described as emission process in the tunneling pictures. According to relationship between probability of outgoing particle with the spectrum of black body radiation for fermion particles, temperature of the elliptical black hole can be obtained and it depend on the azimuthal angle. This result also showed that condition on the surface of elliptical black hole is not in thermal equilibrium.

  8. Investigation of granular impact using positron emission particle tracking

    KAUST Repository

    Marston, Jeremy O.

    2015-04-01

    We present results from an experimental study of granular impact using a combination of high-speed video and positron emission particle tracking (PEPT). The PEPT technique exploits the annihilation of photons from positron decay to determine the position of tracer particles either inside a small granular bed or attached to the object which impacts the bed. We use dense spheres as impactors and the granular beds are comprised of glass beads which are fluidised to achieve a range of different initial packing states. For the first time, we have simultaneously investigated both the trajectory of the sphere, the motion of particles in a 3-D granular bed and particles which jump into the resultant jet, which arises from the collapse of the cavity formed by the impacting sphere.

  9. Positron emission particle tracking-Application and labelling techniques

    Institute of Scientific and Technical Information of China (English)

    David J.Parker; Xianfeng Fan

    2008-01-01

    The positron emission particle tracking (PEPT) technique has been widely used in science and engineering to obtain detailed information on the motion and flow fields of fluids or granular materials in multiphase systems, for example, fluids in rock cracks, chemical reactors and food processors; dynamic behaviour of granular materials in chemical reactors, granulators, mixers, dryers, rotating kilns and ball mills. The information obtained by the PEPT technique can be used to optimise the design, operational conditions for a wide range of industrial process systems, and to evaluate modelling work. The technique is based on tracking radioactively labelled particles (up to three particles) by detecting the pairs of back-to-back 511 ke V -γ-rays arising from annihilation of emitted positrons. It therefore involves a positron camera, location algorithms for calculating the tracer location and speed, and tracer labelling techniques. This paper will review the particle tracking technique from tracking algorithm, tracer labelling to their application.

  10. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2003-01-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. For the engine considered, the upper limit for the ion emission index EIi is of the order of (2-5 x1016 ions/kg-fuel if ion-soot interactions are ignored and the introduction of ion-soot interactions lead about to a 50% reduction. The results also show that most of the soot particles are either positively or negatively charged, the remaining neutral particles representing approximately 20% of the total particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  11. Particle and gaseous emissions from individual diesel and CNG buses

    Science.gov (United States)

    Hallquist, Å. M.; Jerksjö, M.; Fallgren, H.; Westerlund, J.; Sjödin, Å.

    2013-05-01

    In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG)-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz) and CO2 with a non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz). The gaseous constituents (CO, HC and NO) were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.). Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA3.1. The buses studied were diesel-fuelled Euro III-V and CNG-fuelled Enhanced Environmentally Friendly Vehicles (EEVs) with different after-treatment, including selective catalytic reduction (SCR), exhaust gas recirculation (EGR) and with and without diesel particulate filter (DPF). The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average a higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN) were EFPN, DPF = 4.4 ± 3.5 × 1014, EFPN, no DPF = 2.1 ± 1.0 × 1015 and EFPN, CNG = 7.8 ± 5.7 ×1015 kg fuel-1. In the accelerating mode, size-resolved emission factors (EFs) showed unimodal number size distributions with peak diameters of 70-90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode, bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NOx expressed as NO2 equivalents for the diesel buses were on average 27 ± 7 g (kg fuel)-1 and for the CNG buses 41 ± 26 g (kg

  12. Particle and gaseous emissions from individual diesel and CNG buses

    Directory of Open Access Journals (Sweden)

    Å. M. Hallquist

    2013-05-01

    Full Text Available In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz and CO2 with a non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz. The gaseous constituents (CO, HC and NO were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.. Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA3.1. The buses studied were diesel-fuelled Euro III–V and CNG-fuelled Enhanced Environmentally Friendly Vehicles (EEVs with different after-treatment, including selective catalytic reduction (SCR, exhaust gas recirculation (EGR and with and without diesel particulate filter (DPF. The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average a higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN were EFPN, DPF = 4.4 ± 3.5 × 1014, EFPN, no DPF = 2.1 ± 1.0 × 1015 and EFPN, CNG = 7.8 ± 5.7 ×1015 kg fuel−1. In the accelerating mode, size-resolved emission factors (EFs showed unimodal number size distributions with peak diameters of 70–90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode, bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NOx expressed as NO2 equivalents for the diesel buses were on average 27 ± 7 g (kg fuel−1 and for the CNG buses 41

  13. ENVISION, developing Positron Emission Tomography for particle therapy

    CERN Multimedia

    2013-01-01

    Particle therapy is an advanced technique of cancer radiation therapy, using protons or other ions to target the cancerous mass. ENVISION aims at developing medical imaging tools to improve the dose delivery to the patient, to ensure a safer and more effective treatment. The animation illustrates the use of Positron Emission Tomography (PET) for monitoring the dose during treatment. Produced by: CERN KT/Life Sciences and ENVISION Project Management: Manuela Cirilli 3D animation: Jeroen Huijben, Nymus3d

  14. Invisible to Microwaves

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Scientists can't yet make an invisibility cloak like the one that Harry Potter uses.But,for the first time,they've constructed a simple cloaking(1)d__that makes itself and something placed inside it invisible to microwaves.

  15. Radiative forcing from particle emissions by future supersonic aircraft

    Directory of Open Access Journals (Sweden)

    G. Pitari

    2008-07-01

    Full Text Available In this work we focus on the direct radiative forcing (RF of black carbon (BC and sulphuric acid particles emitted by future supersonic aircraft, as well as on the ozone RF due to changes produced by emissions of both gas species (NOx, H2O and aerosol particles capable of affecting stratospheric ozone chemistry. Heterogeneous chemical reactions on the surface of sulphuric acid stratospheric particles (SSA-SAD are the main link between ozone chemistry and supersonic aircraft emissions of sulphur precursors (SO2 and particles (H2O–H2SO4. Photochemical O3 changes are compared from four independent 3-D atmosphere-chemistry models (ACMs, using as input the perturbation of SSA-SAD calculated in the University of L'Aquila model, which includes on-line a microphysics code for aerosol formation and growth. The ACMs in this study use aircraft emission scenarios for the year 2050 developed by AIRBUS as a part of the EU project SCENIC, assessing options for fleet size, engine technology (NOx emission index, Mach number, range and cruising altitude. From our baseline modeling simulation, the impact of supersonic aircraft on sulphuric acid aerosol and BC mass burdens is 53 and 1.5 μg/m2, respectively, with a direct RF of −11.4 and 4.6 mW/m2 (net RF=−6.8 mW/m2. This paper discusses the similarities and differences amongst the participating models in terms of changes to O3 precursors due to aircraft emissions (NOx, HOx,Clx,Brx and the stratospheric ozone sensitivity to them. In the baseline case, the calculated global ozone change is −0.4 ±0.3 DU, with a net radiative forcing (IR+UV of −2.5± 2 mW/m2. The fraction of this O3-RF attributable to SSA-SAD changes is, however, highly variable among the models, depending on the NOx removal

  16. Emissions from Ethanol-Gasoline Blends: A Single Particle Perspective

    Directory of Open Access Journals (Sweden)

    Peter H. McMurry

    2011-06-01

    Full Text Available Due to its agricultural origin and function as a fuel oxygenate, ethanol is being promoted as an alternative biomass-based fuel for use in spark ignition engines, with mandates for its use at state and regional levels. While it has been established that the addition of ethanol to a fuel reduces the particulate mass concentration in the exhaust, little attention has been paid to changes in the physicochemical properties of the emitted particles. In this work, a dynamometer-mounted GM Quad-4 spark ignition engine run without aftertreatment at 1,500 RPM and 100% load was used with four different fuel blends, containing 0, 20, 40 and 85 percent ethanol in gasoline. This allowed the effects of the fuel composition to be isolated from other effects. Instrumentation employed included two Aerosol Time-of-Flight Mass Spectrometers covering different size ranges for analysis of single particle composition, an Aethalometer for black carbon, a Scanning Mobility Particle Sizer for particle size distributions, a Photoelectric Aerosol Sensor for particle-bound polycyclic aromatic hydrocarbon (PAH species and gravimetric filter measurements for particulate mass concentrations. It was found that, under the conditions investigated here, additional ethanol content in the fuel changes the particle size distribution, especially in the accumulation mode, and decreases the black carbon and total particulate mass concentrations. The molecular weight distribution of the PAHs was found to decrease with added ethanol. However, PAHs produced from higher ethanol-content fuels are associated with NO2− (m/z—46 in the single-particle mass spectra, indicating the presence of nitro-PAHs. Compounds associated with the gasoline (e.g., sulfur-containing species are diminished due to dilution as ethanol is added to the fuel relative to those associated with the lubricating oil (e.g., calcium, zinc, phosphate in the single particle spectra. These changes have potential

  17. Humidity control of particle emissions in aeolian systems

    Science.gov (United States)

    McKenna Neuman, Cheryl; Sanderson, Steven

    2008-06-01

    Humidity is an important control of the wind speed required to entrain particles into an air flow and is well known to vary on a global scale, as do dust emissions. This paper reports on wind tunnel experiments which quantify this control through placing a polymer capacitance sensor immediately at the bed surface. The sensor measured changes in the humidity (RH) of the pore air in real time. RH was varied between 15% and 80% and the critical wind speed determined for the release of particles to the air stream. The results strongly support earlier suggestions that fine particles are most affected in relatively dry atmospheres, particularly those which are tightly packed. An analytical model is proposed to describe this relationship which depends on determination of the matric potential from the Kelvin equation. The total contact area between particle asperities adjoined by pendular rings is represented as a power function of the number of layers of adsorbed water. The value of the exponent appears to be governed by the surface roughness of the particles and their packing arrangement. Parallel developments in colloid interface science and atomic force microscopy, relevant to industrial and pharmaceutical applications, support these conclusions in principle and will likely have an important bearing on future progress in parameterization of the proposed model.

  18. [Analysis on oil fume particles in catering industry cooking emission].

    Science.gov (United States)

    Tan, De-Sheng; Kuang, Yuan-Cheng; Liu, Xin; Dai, Fei-Hong

    2012-06-01

    By measuring the particulate matter of oil fume which is over 10 microm or below 10 microm separately and using microradiography and Electrical Low Pressure Impactor (ELPI), it is found out the distributing characteristic of oil fume particles in catering industry cooking emission. The result shows that the diameter of the oil fume particles which was sedimentated in the kitchen is between 10-400 microm, the concentration peak value is between 10-100 microm. The diameter of oil fume aerosol is mostly smaller than 1 microm, while the concentration peak value is between 0.063-0.109 microm. In addition, the mass concentration peak value is between 6.560-9.990 microm. Through the analysis to the physical characteristics of oil fume from catering industry cooking emissions, the eigenvalue of the oil fume has been found and the feature matter for monitoring the oil fume has been discovered to provide a reasonable standard for controlling and monitoring the catering industry cooking emission.

  19. Time-resolved characterization of primary particle emissions and secondary particle formation from a modern gasoline passenger car

    Science.gov (United States)

    Karjalainen, Panu; Timonen, Hilkka; Saukko, Erkka; Kuuluvainen, Heino; Saarikoski, Sanna; Aakko-Saksa, Päivi; Murtonen, Timo; Bloss, Matthew; Dal Maso, Miikka; Simonen, Pauli; Ahlberg, Erik; Svenningsson, Birgitta; Brune, William Henry; Hillamo, Risto; Keskinen, Jorma; Rönkkö, Topi

    2016-07-01

    Changes in vehicle emission reduction technologies significantly affect traffic-related emissions in urban areas. In many densely populated areas the amount of traffic is increasing, keeping the emission level high or even increasing. To understand the health effects of traffic-related emissions, both primary (direct) particulate emission and secondary particle formation (from gaseous precursors in the exhaust emissions) need to be characterized. In this study, we used a comprehensive set of measurements to characterize both primary and secondary particulate emissions of a Euro 5 level gasoline passenger car. Our aerosol particle study covers the whole process chain in emission formation, from the tailpipe to the atmosphere, and also takes into account differences in driving patterns. We observed that, in mass terms, the amount of secondary particles was 13 times higher than the amount of primary particles. The formation, composition, number and mass of secondary particles was significantly affected by driving patterns and engine conditions. The highest gaseous and particulate emissions were observed at the beginning of the test cycle when the performance of the engine and the catalyst was below optimal. The key parameter for secondary particle formation was the amount of gaseous hydrocarbons in primary emissions; however, also the primary particle population had an influence.

  20. Particle Acceleration and Nonthermal Emission in Relativistic Astrophysical Shocks

    Science.gov (United States)

    Sironi, Lorenzo

    numerical technique that I have developed in order to extract ab initio photon spectra from PIC simulations of shocks. With this technique, I have modeled the emission from GRB jets, ruling out a class of models that relied on the so-called jitter radiation. This reinforces the idea that a detailed understanding of the micro-physics of particle acceleration in relativistic shocks is required in order to correctly interpret the emission signatures of astrophysical nonthermal sources.

  1. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2002-11-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  2. Invisible Higgs and Dark Matter

    DEFF Research Database (Denmark)

    Heikinheimo, Matti; Tuominen, Kimmo; Virkajärvi, Jussi Tuomas

    2012-01-01

    We investigate the possibility that a massive weakly interacting fermion simultaneously provides for a dominant component of the dark matter relic density and an invisible decay width of the Higgs boson at the LHC. As a concrete model realizing such dynamics we consider the minimal walking...... technicolor, although our results apply more generally. Taking into account the constraints from the electroweak precision measurements and current direct searches for dark matter particles, we find that such scenario is heavily constrained, and large portions of the parameter space are excluded....

  3. Performing Belonging, celebrating invisibility?

    DEFF Research Database (Denmark)

    Juul, Kristine

    2014-01-01

    Serbian migrants living transnational lives consciously or unconsciously move between visibility and invisibility in their performance of migrant success stories. A case in point are public festivals, performed to make visible migrants’ successful inclusion in Danish society, i.e. celebrating...... invisibility. Meanwhile, other celebrations are consciously relegated to the invisible confines of the Serbian homeland. This article analyses celebrations in Denmark and in Serbia and shows how visible displays of ethnicity and difference tend to turn into easily palatable heritage versions of Serbian culture...... when performed in a Danish context. In turn, the visibility acquired through celebrations of migrants’ belonging in their homeland is inclined to render invisible those who did not take part in the migration experience....

  4. UA1: W particle decay

    CERN Multimedia

    1982-01-01

    The discovery of the W particle in the UA1 detector from the October-December 1982 run of the proton-antiproton collider, producing a high transverse energy electron (arrowed). This particle is produced back-to-back with 'missing energy', indicative of the emission of an invisible neutrino. The UA1 detector ran on the SPS accelerator at CERN between 1981 and 1993.

  5. Invisibility and PT symmetry

    OpenAIRE

    MOSTAFAZADEH, Ali

    2013-01-01

    PHYSICAL REVIEW A 87, 012103 (2013) Invisibility and PT symmetry Ali Mostafazadeh* Department of Mathematics, Koc¸ University, Sarıyer 34450, Istanbul, Turkey (Received 9 July 2012; published 3 January 2013) For a general complex scattering potential defined on a real line, we show that the equations governing invisibility of the potential are invariant under the combined action of parity and time-reversal (PT ) transformation. We determine the PT -symmetric as well as no...

  6. Particle and gaseous emissions from individual diesel and CNG buses

    Directory of Open Access Journals (Sweden)

    Å. M. Hallquist

    2012-10-01

    Full Text Available In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz and CO2 with non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz. The gaseous constituents (CO, HC and NO were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.. Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA 3.1. The buses studied were diesel-fuelled Euro II–V and CNG-fuelled Enhanced Environmental Friendly Vehicles (EEVs with different after-treatment, including selective catalytic reduction (SCR, exhaust gas recirculation (EGR and with and without diesel particulate filter (DPF. The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN were EFPN, DPF = 8.0 ± 3.1 × 1014, EFPN, no DPF =2.8 ± 1.6 × 1015 and EFPN, CNG = 7.8 ± 5.7 × 1015 (kg fuel−1. In the accelerating mode size-resolved EFs showed unimodal number size distributions with peak diameters of 70–90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm.

    Emission

  7. On the unification of aircraft ultrafine particle emission data

    Energy Technology Data Exchange (ETDEWEB)

    Kaercher, B.; Busen, R. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Turco, R.P.; Yu Fangqun [California Univ., Los Angeles, CA (United States). Dept. of Atmospheric Sciences; Danilin, M.Y.; Weisenstein, D.K. [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States); Miake-Lye, R.C. [Aerodyne Research, Inc., Billerica, MA (United States)

    2000-03-01

    To predict the environmental impacts of future commercial aviation, intensive studies have been launched to measure the properties and effects of aircraft emissions. These observations have revealed an extremely wide variance with respect to the number and sizes of the particles produced in the exhaust plumes. Aircraft aerosol ultimately contributes to the population of cloud-forming nuclei, and may lead to significant global radiative and chemical perturbations. In this paper, recent discoveries are coordinated and unified in the form of a physically consistent plume aerosol model that explains most of the observational variance. Using this new approach, it is now practical to carry out reliable global atmospheric simulations of aircraft effects, as demonstrated by a novel assessment of the perturbation of the stratospheric aerosol layer by a supersonic aircraft fleet. (orig.)

  8. On the unification of aircraft ultrafine particle emission data

    Energy Technology Data Exchange (ETDEWEB)

    Kaercher, B.; Busen, R. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Turco, R.P.; Yu Fangqun [California Univ., Los Angeles, CA (United States). Dept. of Atmospheric Sciences; Danilin, M.Y.; Weisenstein, D.K. [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States); Miake-Lye, R.C. [Aerodyne Research, Inc., Billerica, MA (United States)

    2000-03-01

    To predict the environmental impacts of future commercial aviation, intensive studies have been launched to measure the properties and effects of aircraft emissions. These observations have revealed an extremely wide variance with respect to the number and sizes of the particles produced in the exhaust plumes. Aircraft aerosol ultimately contributes to the population of cloud-forming nuclei, and may lead to significant global radiative and chemical perturbations. In this paper, recent discoveries are coordinated and unified in the form of a physically consistent plume aerosol model that explains most of the observational variance. Using this new approach, it is now practical to carry out reliable global atmospheric simulations of aircraft effects, as demonstrated by a novel assessment of the perturbation of the stratospheric aerosol layer by a supersonic aircraft fleet. (orig.)

  9. Particle acceleration by stimulated emission of radiation in cylindrical waveguide

    Institute of Scientific and Technical Information of China (English)

    TIAN Xiu-Fang; WU Cong-Feng; JIA Qi-Ka

    2015-01-01

    In particle acceleration by stimulated emission of radiation (PASER),efficient interaction occurs when a train of micro-bunches has periodicity identical to the resonance frequency of the medium.Previous theoretical calculations based on the simplified model have only considered the energy exchange in the boundless condition.Under experimental conditions,however,the gas active medium must be guided by the metal waveguide.In this paper,we have developed a model of the energy exchange between a train of micro-bunches and a gas mixture active medium in a waveguide boundary for the first time,based on the theory of electromagnetic fields,and made detailed analysis and calculations with MathCAD.The results show that energy density can be optimized to a certain value to get the maximum energy exchange.

  10. Invisible Display in Aluminum

    DEFF Research Database (Denmark)

    Prichystal, Jan Phuklin; Hansen, Hans Nørgaard; Bladt, Henrik Henriksen

    2005-01-01

    Bang & Olufsen a/s has been working with ideas for invisible integration of displays in metal surfaces. Invisible integration of information displays traditionally has been possible by placing displays behind transparent or semitransparent materials such as plastic or glass. The wish for an integ...... be obtained by shining light from the backside of the workpiece. When there is no light from the backside, the front surface seems totally untouched. This was achieved by laser ablation with ultra-short pulses.......Bang & Olufsen a/s has been working with ideas for invisible integration of displays in metal surfaces. Invisible integration of information displays traditionally has been possible by placing displays behind transparent or semitransparent materials such as plastic or glass. The wish...... for an integrated display in a metal surface is often ruled by design and functionality of a product. The integration of displays in metal surfaces requires metal removal in order to clear the area of the display to some extent. The idea behind an invisible display in Aluminum concerns the processing of a metal...

  11. Detection of Bioaerosols Using Single Particle Thermal Emission Spectroscopy (First-year Report)

    Science.gov (United States)

    2012-02-01

    Detection of Bioaerosols using Single Particle Thermal Emission Spectroscopy (First-year Report) by Dr. Kristan P. Gurton, Melvin Felton, and...Research Laboratory Adelphi, MD 20783-1197 ARL-TR-5934 February 2012 Detection of Bioaerosols using Single Particle Thermal Emission...October 2011 4. TITLE AND SUBTITLE Detection of Bioaerosols using Single Particle Thermal Emission Spectroscopy (First-year Report) 5a. CONTRACT

  12. Particle filtering based structural assessment with acoustic emission sensing

    Science.gov (United States)

    Yan, Wuzhao; Abdelrahman, Marwa; Zhang, Bin; Ziehl, Paul

    2017-02-01

    Nuclear structures are designed to withstand severe loading events under various stresses. Over time, aging of structural systems constructed with concrete and steel will occur. This deterioration may reduce service life of nuclear facilities and/or lead to unnecessary or untimely repairs. Therefore, online monitoring of structures in nuclear power plants and waste storage has drawn significant attention in recent years. Of many existing non-destructive evaluation and structural monitoring approaches, acoustic emission is promising for assessment of structural damage because it is non-intrusive and is sensitive to corrosion and crack growth in reinforced concrete elements. To provide a rapid, actionable, and graphical means for interpretation Intensity Analysis plots have been developed. This approach provides a means for classification of damage. Since the acoustic emission measurement is only an indirect indicator of structural damage, potentially corrupted by non-genuine data, it is more suitable to estimate the states of corrosion and cracking in a Bayesian estimation framework. In this paper, we will utilize the accelerated corrosion data from a specimen at the University of South Carolina to develop a particle filtering-based diagnosis and prognosis algorithm. Promising features of the proposed algorithm are described in terms of corrosion state estimation and prediction of degradation over time to a predefined threshold.

  13. Particle emissions from laboratory activities involving carbon nanotubes

    Science.gov (United States)

    Lo, Li-Ming; Tsai, Candace S.-J.; Heitbrink, William A.; Dunn, Kevin H.; Topmiller, Jennifer; Ellenbecker, Michael

    2017-08-01

    This site study was conducted in a chemical laboratory to evaluate nanomaterial emissions from 20-30-nm-diameter bundles of single-walled carbon nanotubes (CNTs) during product development activities. Direct-reading instruments were used to monitor the tasks in real time, and airborne particles were collected using various methods to characterize released nanomaterials using electron microscopy and elemental carbon (EC) analyses. CNT clusters and a few high-aspect-ratio particles were identified as being released from some activities. The EC concentration (0.87 μg/m3) at the source of probe sonication was found to be higher than other activities including weighing, mixing, centrifugation, coating, and cutting. Various sampling methods all indicated different levels of CNTs from the activities; however, the sonication process was found to release the highest amounts of CNTs. It can be cautiously concluded that the task of probe sonication possibly released nanomaterials into the laboratory and posed a risk of surface contamination. Based on these results, the sonication of CNT suspension should be covered or conducted inside a ventilated enclosure with proper filtration or a glovebox to minimize the potential of exposure.

  14. Test Method for High β Particle Emission Rate of 63Ni Source Plate

    Directory of Open Access Journals (Sweden)

    ZHANG Li-feng

    2015-01-01

    Full Text Available For the problem of measurement difficulties of β particle emission rate of Ni-63 source plate used for Ni-63 betavoltaic battery, a relative test method of scintillation current method was erected according to the measurement principle of scintillation detector.β particle emission rate of homemade Ni-63 source plate was tested by the method, and the test results were analysed and evaluated, it was initially thought that scintillation current method was a feasible way of testing β particle emission rate of Ni-63 source plate with high β particle emission rate.

  15. MONDO: a neutron tracker for particle therapy secondary emission characterisation

    Science.gov (United States)

    Marafini, M.; Gasparini, L.; Mirabelli, R.; Pinci, D.; Patera, V.; Sciubba, A.; Spiriti, E.; Stoppa, D.; Traini, G.; Sarti, A.

    2017-04-01

    Tumour control is performed in particle therapy using particles and ions, whose high irradiation precision enhances the effectiveness of the treatment, while sparing the healthy tissue surrounding the target volume. Dose range monitoring devices using photons and charged particles produced by the beam interacting with the patient’s body have already been proposed, but no attempt has been made yet to exploit the detection of the abundant neutron component. Since neutrons can release a significant dose far away from the tumour region, precise measurements of their flux, production energy and angle distributions are eagerly sought in order to improve the treatment planning system (TPS) software. It will thus be possible to predict not only the normal tissue toxicity in the target region, but also the risk of late complications in the whole body. The aforementioned issues underline the importance of an experimental effort devoted to the precise characterisation of neutron production, aimed at the measurement of their abundance, emission point and production energy. The technical challenges posed by a neutron detector aimed at high detection efficiency and good backtracking precision are addressed within the MONDO (monitor for neutron dose in hadrontherapy) project, whose main goal is to develop a tracking detector that can target fast and ultrafast neutrons. A full reconstruction of two consecutive elastic scattering interactions undergone by the neutrons inside the detector material will be used to measure their energy and direction. The preliminary results of an MC simulation performed using the FLUKA software are presented here, together with the DSiPM (digital SiPM) readout implementation. New detector readout implementations specifically tailored to the MONDO tracker are also discussed, and the neutron detection efficiency attainable with the proposed neutron tracking strategy are reported.

  16. Spying an invisible Higgs

    CERN Document Server

    Bernaciak, Catherine; Schichtel, Peter; Tattersall, Jamie

    2014-01-01

    We investigate the potential of multivariate techniques to improve the LHC search for invisible Higgs decays in weak boson fusion. We find that in the coming runs the LHC will be able to probe an invisible Higgs width of 28% within a year and 3.5% during a high luminosity run. A significant improvement over these estimates requires an analysis of QCD radiation patterns down to 10 GeV. Such an analysis can improve the reach at the high luminosity run to 2%. Throughout our analysis we employ a conservative, data driven background determination.

  17. Physical characterization of the fine particle emissions from commercial aircraft engines during the Aircraft Particle Emissions Experiment (APEX) 1 to 3

    Science.gov (United States)

    The f1me particulate matter (PM) emissions from nine commercial aircraft engine models were determined by plume sampling during the three field campaigns of the Aircraft Particle Emissions Experiment (APEX). Ground-based measurements were made primarily at 30 m behind the engine ...

  18. The Invisible Cinema

    NARCIS (Netherlands)

    Hanich, Julian; Fossati, Giovanna; van den Oever, Annie

    2016-01-01

    The Invisible Cinema was an experimental movie theater designed by an experimental filmmaker. Devised by the Austrian avantgardist Peter Kubelka, it served as the first place of exhibition for the Anthology Film Archives in New York. Apart from the screen (and some exit signs and aisle lights instal

  19. Making Invisible Forces Visible

    DEFF Research Database (Denmark)

    Ratner, Helene; Pors, Justine Grønbæk

    2013-01-01

    This paper investigates managerial tactics of visualisation when a need to know and manage employees' values and attitudes is expressed. Using the Danish public school as a case study, we explore how school managers use teachers' emotions to render visible presumably invisible information about...

  20. Invisible Display in Aluminum

    DEFF Research Database (Denmark)

    Prichystal, Jan Phuklin; Hansen, Hans Nørgaard; Bladt, Henrik Henriksen

    2005-01-01

    for an integrated display in a metal surface is often ruled by design and functionality of a product. The integration of displays in metal surfaces requires metal removal in order to clear the area of the display to some extent. The idea behind an invisible display in Aluminum concerns the processing of a metal...

  1. The Invisibility of Steam

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2014-01-01

    Almost everyone "knows" that steam is visible. After all, one can see the cloud of white issuing from the spout of a boiling tea kettle. In reality, steam is the gaseous phase of water and is invisible. What you see is light scattered from the tiny droplets of water that are the result of the condensation of the steam as its temperature…

  2. Healing Invisible Wounds

    Science.gov (United States)

    Adams, Erica J.

    2010-01-01

    As many as 9 in 10 justice-involved youth are affected by traumatic childhood experiences. According to "Healing Invisible Wounds: Why Investing in Trauma-Informed Care for Children Makes Sense," between 75 and 93 percent of youth currently incarcerated in the justice system have had at least one traumatic experience, including sexual…

  3. Healing Invisible Wounds

    Science.gov (United States)

    Adams, Erica J.

    2010-01-01

    As many as 9 in 10 justice-involved youth are affected by traumatic childhood experiences. According to "Healing Invisible Wounds: Why Investing in Trauma-Informed Care for Children Makes Sense," between 75 and 93 percent of youth currently incarcerated in the justice system have had at least one traumatic experience, including sexual…

  4. Signatures of the Invisible

    CERN Multimedia

    Strom, D

    2003-01-01

    On the Net it is possible to take a look at art from afar via Virtual Museums. One such exhibition was recently in the New York Museum of Modern Art's branch, PS1. Entitled 'Signatures of the Invisible' it was a collaborative effort between artists and physicists (1/2 page).

  5. Time-resolved characterization of primary and secondary particle emissions of a modern gasoline passenger car

    Directory of Open Access Journals (Sweden)

    P. Karjalainen

    2015-11-01

    Full Text Available Changes in traffic systems and vehicle emission reduction technologies significantly affect traffic-related emissions in urban areas. In many densely populated areas the amount of traffic is increasing, keeping the emission level high or even increasing. To understand the health effects of traffic related emissions, both primary and secondary particles that are formed in the atmosphere from gaseous exhaust emissions need to be characterized. In this study we used a comprehensive set of measurements to characterize both primary and secondary particulate emissions of a modern gasoline passenger car. Our aerosol particle study covers the whole process chain in emission formation, from the engine to the atmosphere, and takes into account also differences in driving patterns. We observed that in mass terms, the amount of secondary particles was 13 times higher than the amount of primary particles. The formation, composition, number, and mass of secondary particles was significantly affected by driving patterns and engine conditions. The highest gaseous and particulate emissions were observed at the beginning of the test cycle when the performance of the engine and the catalyst was below optimal. The key parameter for secondary particle formation was the amount of gaseous hydrocarbons in primary emissions; however, also the primary particle population had an influence. Thus, in order to enhance human health and wellbeing in urban areas, our study strongly indicates that in future legislation, special attention should be directed into the reduction of gaseous hydrocarbons.

  6. Search for invisible decay modes of the Higgs boson with the ATLAS detector

    CERN Document Server

    Trovatelli, Monica; The ATLAS collaboration

    2016-01-01

    The total decay width of the Higgs boson has not yet been constrained precisely with the LHC data. Some of the width could be associated to decays to invisible particles, for example Dark Matter particles. A search for invisible decays of the Higgs boson is performed using about 10 fb-1 of p-p collisions at 13 TeV.

  7. Invisibility and PT Symmetry: A Simple Geometrical Viewpoint

    Directory of Open Access Journals (Sweden)

    Luis L. Sánchez-Soto

    2014-05-01

    Full Text Available We give a simplified account of the properties of the transfer matrix for a complex one-dimensional potential, paying special attention to the particular instance of unidirectional invisibility. In appropriate variables, invisible potentials appear as performing null rotations, which lead to the helicity-gauge symmetry of massless particles. In hyperbolic geometry, this can be interpreted, via Möbius transformations, as parallel displacements, a geometric action that has no Euclidean analogy.

  8. Sensitivity to an Invisibly Decaying Higgs Boson

    CERN Document Server

    The ATLAS collaboration

    2009-01-01

    Many extensions of the Standard Model include Higgs bosons decaying predominantly or partially to non-interacting particles such as the SUSY Lightest Supersymmetric Particle (LSP). To set limits on the production cross-section times the branching fraction to invisible decay products of such Higgs bosons with the ATLAS detector requires an examination of specific production modes such as the associated production (ZH) or the vector boson fusion (VBF) process. The predominant Standard Model backgrounds for these processes are ZZ to nunu for the ZH channel and jets from QCD processes and W or Z bosons produced in association with jets for the VBF channel. The sensitivity to an invisibly decaying Higgs boson is investigated in this paper using fully simulated ATLAS data for both signal and background. The ATLAS potential for triggering these events is also discussed.

  9. Visible Effects of Invisible Hidden Valley Radiation

    CERN Document Server

    Carloni, Lisa

    2010-01-01

    Assuming there is a new gauge group in a Hidden Valley, and a new type of radiation, can we observe it through its effect on the kinematic distributions of recoiling visible particles? Specifically, what are the collider signatures of radiation in a hidden sector? We address these questions using a generic SU(N)-like Hidden Valley model that we implement in Pythia. We find that in both the e+e- and the LHC cases the kinematic distributions of the visible particles can be significantly affected by the valley radiation. Without a proper understanding of such effects, inferred masses of "communicators" and of invisible particles can be substantially off.

  10. An acoustic invisible gateway

    CERN Document Server

    Zhu, Yi-Fan; Liang, Bin; Kan, Wei-Wei; Yang, Jun; Cheng, Jian-Chun

    2015-01-01

    The recently-emerged concept of "invisible gateway" with the extraordinary capability to block the waves but allow the passage of other entities has attracted great attentions due to the general interests in illusion devices. However, the possibility to realize such a fascinating phenomenon for acoustic waves has not yet been explored, which should be of paramount significance for acoustical applications but would necessarily involve experimental difficulty. Here we design and experimentally demonstrate an acoustic invisible gateway (AIG) capable of concealing a channel under the detection of sound. Instead of "restoring" a whole block of background medium by using transformation acoustics that inevitably requires complementary or restoring media with extreme parameters, we propose an inherently distinct methodology that only aims at engineering the surface impedance at the "gate" to mimic a rigid "wall" and can be conveniently implemented by decorating meta-structures behind the channel. Such a simple yet ef...

  11. An Invisible Metallic Mesh

    CERN Document Server

    Ye, Dexin; Joannopoulos, John D; Soljačić, Marin; Ran, Lixin

    2015-01-01

    We introduce a solid material that is itself invisible, possessing identical electromagnetic properties as air (i.e. not a cloak) at a desired frequency. Such a material could provide improved mechanical stability, electrical conduction and heat dissipation to a system, without disturbing incident electromagnetic radiation. One immediate application would be towards perfect antenna radomes. Unlike cloaks, such a transparent and self-invisible material has yet to be demonstrated. Previous research has shown that a single sphere or cylinder coated with plasmonic or dielectric layers can have a dark-state with considerably suppressed scattering cross-section, due to the destructive interference between two resonances in one of its scattering channels. Nevertheless, a massive collection of these objects will have an accumulated and detectable disturbance to the original field distribution. Here we overcome this bottleneck by lining up the dark-state frequencies in different channels. Specifically, we derive analy...

  12. Emissions of Trace Gases and Particles from Two Ships in the Southern Atlantic Ocean

    Science.gov (United States)

    Sinha, Parikhit; Hobbs, Peter V.; Yokelson, Robert J.; Christian, Ted J.; Kirchstetter, Thomas W.; Bruintjes, Roelof

    2003-01-01

    Measurements were made of the emissions of particles and gases from two diesel-powered ships in the southern Atlantic Ocean off the coast of Namibia. The measurements are used to derive emission factors from ships of three species not reported previously, namely, black carbon, accumulation-mode particles, and cloud condensation nuclei (CCN), as well as for carbon dioxide, carbon monoxide (CO), methane (CH4), non-methane hydrocarbons, sulfur dioxide (SO2), nitrogen oxides (NOx), and condensation nuclei. The effects of fuel grade and engine power on ship emissions are discussed. The emission factors are combined with fuel usage data to obtain estimates of global annual emissions of various particles and gases from ocean-going ships. Global emissions of black carbon, accumulation- mode particles, and CCN from ocean-going ships are estimated to be 19-26 Gg yr(sup -1), (4.4-6.1) x 10(exp 26) particles yr(sup -1), and (1.0-1.5) x l0(exp 26) particles yr(sup -1), respectively. Black carbon emissions from ocean-going ships are approximately 0.2% of total anthropogenic emissions. Emissions of NOx and SO2 from ocean-going ships are approximately 10-14% and approximately 3-4%, respectively, of the total emissions of these species from the burning of fossil fuels, and approximately 40% and approximately 70%, respectively, of the total emissions of these species from the burning of biomass. Global annual emissions of CO and CH4 from ocean-going ships are approximately 2% and approximately 2-5%, respectively, of natural oceanic emissions of these species.

  13. Invisible Navigation (or Impossible?).

    OpenAIRE

    Özcan, Oğuzhan; O'Neil, Mary Lou

    2013-01-01

    Abstract: This article introduces an experimental artwork on moving mobile interfaces. It aims to answer the question: Is it possible to navigate a part of a large image composition, moving a smaller interface of a mobile device in a certain direction such as left and right, back and forth or up and down? The article then outlines the new concept of “Invisible (or impossible) Navigation” and discusses the output of artistic practices which address the “Labyrinth of Art”.

  14. Determining size-specific emission factors for environmental tobacco smoke particles

    Energy Technology Data Exchange (ETDEWEB)

    Klepeis, Neil E.; Apte, Michael G.; Gundel, Lara A.; Sextro, Richard G.; Nazaroff, William W.

    2002-07-07

    Because size is a major controlling factor for indoor airborne particle behavior, human particle exposure assessments will benefit from improved knowledge of size-specific particle emissions. We report a method of inferring size-specific mass emission factors for indoor sources that makes use of an indoor aerosol dynamics model, measured particle concentration time series data, and an optimization routine. This approach provides--in addition to estimates of the emissions size distribution and integrated emission factors--estimates of deposition rate, an enhanced understanding of particle dynamics, and information about model performance. We applied the method to size-specific environmental tobacco smoke (ETS) particle concentrations measured every minute with an 8-channel optical particle counter (PMS-LASAIR; 0.1-2+ micrometer diameters) and every 10 or 30 min with a 34-channel differential mobility particle sizer (TSI-DMPS; 0.01-1+ micrometer diameters) after a single cigarette or cigar was machine-smoked inside a low air-exchange-rate 20 m{sup 3} chamber. The aerosol dynamics model provided good fits to observed concentrations when using optimized values of mass emission rate and deposition rate for each particle size range as input. Small discrepancies observed in the first 1-2 hours after smoking are likely due to the effect of particle evaporation, a process neglected by the model. Size-specific ETS particle emission factors were fit with log-normal distributions, yielding an average mass median diameter of 0.2 micrometers and an average geometric standard deviation of 2.3 with no systematic differences between cigars and cigarettes. The equivalent total particle emission rate, obtained integrating each size distribution, was 0.2-0.7 mg/min for cigars and 0.7-0.9 mg/min for cigarettes.

  15. Development of experimental methods to investigate non-exhaust particle emissions from a light duty vehicle

    OpenAIRE

    Mathissen, Marcel

    2014-01-01

    Vehicle related non-exhaust particle emissions resulting from the abrasion of brakes, tires, road and the resuspension of road dust may contribute considerably to ambient air pollution. While exhaust particulate matter emissions are expected to decrease, non-exhaust emissions will rise due to higher traffic volume and the absence of legal regulations. However, there is still limited scientific knowledge of non-exhaust emissions, especially for the climate conditions found in central Europe...

  16. Exploring the academic invisible web

    OpenAIRE

    Lewandowski, Dirk; Mayr, Philipp

    2006-01-01

    Purpose: To provide a critical review of Bergman’s 2001 study on the Deep Web. In addition, we bring a new concept into the discussion, the Academic Invisible Web (AIW). We define the Academic Invisible Web as consisting of all databases and collections relevant to academia but not searchable by the general-purpose internet search engines. Indexing this part of the Invisible Web is central to scientific search engines. We provide an overview of approaches followed thus far. Design/methodol...

  17. Exploring the academic invisible web

    OpenAIRE

    Lewandowski, Dirk

    2006-01-01

    The Invisible Web is often discussed in the academic context, where its contents (mainly in the form of databases) are of great importance. But this discussion is mainly based on some seminal research done by Sherman and Price (2001) and Bergman (2001), respectively. We focus on the types of Invisible Web content relevant for academics and the improvements made by search engines to deal with these content types. In addition, we question the volume of the Invisible Web as stated by Bergman. Ou...

  18. The Sun and its Planets as detectors for invisible matter

    Science.gov (United States)

    Bertolucci, Sergio; Zioutas, Konstantin; Hofmann, Sebastian; Maroudas, Marios

    2017-09-01

    Gravitational lensing of invisible streaming matter towards the Sun with speeds around 10-4 to 10-3 c could be the explanation of the puzzling solar flares and the unexplained solar emission in the EUV. Assuming that this invisible massive matter has some form of interaction with normal matter and that preferred directions exist in its flow, then one would expect a more pronounced solar activity at certain planetary heliocentric longitudes. This is best demonstrated in the case of the Earth and the two inner planets, considering their relatively short revolution time (365, 225 and 88 days) in comparison to a solar cycle of about 11 years. We have analyzed the solar flares as well as the EUV emission in the periods 1976-2015 and 1999-2015, respectively. The results derived from each data set mutually exclude systematics as the cause of the observed planetary correlations. We observe statistically significant signals when one or more planets have heliocentric longitudes mainly between 230° and 300°. We also analyzed daily data of the global ionization degree of the dynamic Earth atmosphere taken in the period 1995-2012. Again here, we observe a correlation between the total atmospheric electron content (TEC) and the orbital position of the inner three planets. Remarkably, the strongest correlation appears with the phase of the Moon. The broad velocity spectrum of the assumed constituents makes it difficult at this stage to identify its source(s) in space. More refined analyses might in the future increase the precision in the determination of the stream(s) direction and possibly allow to infer some properties of its constituents. Presently, no firmly established model of massive streaming particles exists, although in the literature there are abundant examples of hypotheses. Among them, the anti-quark nuggets model for dark matter seems the better suited to explain our observations and deserves further study.

  19. Missing energy signature from invisible decays of dark photons at the CERN SPS

    CERN Document Server

    Gninenko, S N; Kirsanov, M M; Kirpichnikov, D V

    2016-01-01

    The dark photon ($A'$) production through the mixing with the bremsstrahlung photon from the electron scattering off nuclei can be accompanied by the dominant invisible $A'$ decay into dark-sector particles. In this work we discuss the missing energy signature of this process in the experiment NA64 aiming at the search for $A'\\to invisible$ decays with a high-energy electron beam at the CERN SPS. We show the distinctive distributions of variables that can be used to distinguish the $A'\\to invisible$ signal from background. The results of the detailed simulation of the detector response for the events with and without $A'$ emission are presented. The efficiency of the signal event selection is estimated. It is used to evaluate the sensitivity of the experiment and show that it allows to probe the still unexplored area of the mixing strength $10^{-6}\\lesssim \\epsilon \\lesssim 10^{-2}$ and masses up to $M_{A'} \\lesssim 1$ GeV. The results obtained are compared with the results from other calculations. In the cas...

  20. Missing energy signature from invisible decays of dark photons at the CERN SPS

    Science.gov (United States)

    Gninenko, S. N.; Krasnikov, N. V.; Kirsanov, M. M.; Kirpichnikov, D. V.

    2016-11-01

    The dark photon (A' ) production through the mixing with the bremsstrahlung photon from the electron scattering off nuclei can be accompanied by the dominant invisible A' decay into dark-sector particles. In this work we discuss the missing energy signature of this process in the experiment NA64 aiming at the search for A'→invisible decays with a high-energy electron beam at the CERN SPS (The Super Proton Synchrotron). We show the distinctive distributions of variables that can be used to distinguish the A'→invisible signal from background. The results of the detailed simulation of the detector response for the events with and without A' emission are presented. The efficiency of the signal event selection is estimated. It is used to evaluate the sensitivity of the experiment and show that it allows us to probe the still unexplored area of the mixing strength 10-6≲ɛ ≲10-2 and masses up to MA'≲1 GeV . The results obtained are compared with the results from other calculations. In the case of the signal observation, a possibility of extraction of the parameters MA' and ɛ by using the shape of the missing energy spectrum is discussed.

  1. Functionalization of emissive conjugated polymer nanoparticles by coprecipitation: consequences for particle photophysics and colloidal properties

    Science.gov (United States)

    Singh, Amita; Bezuidenhout, Michael; Walsh, Nichola; Beirne, Jason; Felletti, Riccardo; Wang, Suxiao; Fitzgerald, Kathleen T.; Gallagher, William M.; Kiely, Patrick; Redmond, Gareth

    2016-07-01

    The functionalization of polyfluorene (PFO) nanoparticles by coprecipitation of the conjugated polymer with an amphiphilic comb polymer, consisting of a hydrophobic polystyrene backbone with hydrophilic, carboxylic acid-terminated polyethylene oxide side-chains (PS-PEG-COOH), is investigated. The comb polymer affects the properties of the formed hybrid nanoparticles. Non-functionalized particles are typically larger (28 nm) than functionalized ones (20 nm); peak molar extinction coefficients are found to differ in a similar trend. Zeta potentials are negative, consistent with negative surface charge on PFO particles due to chemical defect formation, with additional charge on functionalized particles due to the pendant carboxylic acid groups. Emission quantum yields of functionalized particles are typically larger, consistent with lower efficiency of energy transfer to quenchers in smaller particles and weaker PFO interchain interactions due to chain dilution. The trend in per-particle fluorescence brightness values, as confirmed by single particle fluorescence imaging, reflects the nanoparticle extinction coefficients. Photostability studies on aqueous dispersions of hybrid particles indicate mild photobrightening under continuous illumination while PFO particles exhibit slow exponential emission decay. Functionalized particles are also resistant to aggregation during exposure to adenocarcinoma cells. Generally, the hybrid particles exhibit more favorable time-, pH- and medium-dependent stabilities, likely due to steric and electrostatic stabilization by PEG-carboxylic acid functionalities. Overall, the functionalized particles exhibit attractive properties: Reasonably small size, tight size distribution, high absorption cross section, radiative rate and emission quantum yield, excellent brightness and photostability, and good colloidal stability.

  2. Effect of fuel injection pressure on a heavy-duty diesel engine nonvolatile particle emission.

    Science.gov (United States)

    Lähde, Tero; Rönkkö, Topi; Happonen, Matti; Söderström, Christer; Virtanen, Annele; Solla, Anu; Kytö, Matti; Rothe, Dieter; Keskinen, Jorma

    2011-03-15

    The effects of the fuel injection pressure on a heavy-duty diesel engine exhaust particle emissions were studied. Nonvolatile particle size distributions and gaseous emissions were measured at steady-state engine conditions while the fuel injection pressure was changed. An increase in the injection pressure resulted in an increase in the nonvolatile nucleation mode (core) emission at medium and at high loads. At low loads, the core was not detected. Simultaneously, a decrease in soot mode number concentration and size and an increase in the soot mode distribution width were detected at all loads. Interestingly, the emission of the core was independent of the soot mode concentration at load conditions below 50%. Depending on engine load conditions, growth of the geometric mean diameter of the core mode was also detected with increasing injection pressure. The core mode emission and also the size of the mode increased with increasing NOx emission while the soot mode size and emission decreased simultaneously.

  3. Chamber bioaerosol study: human emissions of size-resolved fluorescent biological aerosol particles.

    Science.gov (United States)

    Bhangar, S; Adams, R I; Pasut, W; Huffman, J A; Arens, E A; Taylor, J W; Bruns, T D; Nazaroff, W W

    2016-04-01

    Humans are a prominent source of airborne biological particles in occupied indoor spaces, but few studies have quantified human bioaerosol emissions. The chamber investigation reported here employs a fluorescence-based technique to evaluate bioaerosols with high temporal and particle size resolution. In a 75-m(3) chamber, occupant emission rates of coarse (2.5-10 μm) fluorescent biological aerosol particles (FBAPs) under seated, simulated office-work conditions averaged 0.9 ± 0.3 million particles per person-h. Walking was associated with a 5-6× increase in the emission rate. During both walking and sitting, 60-70% or more of emissions originated from the floor. The increase in emissions during walking (vs. while sitting) was mainly attributable to release of particles from the floor; the associated increased vigor of upper body movements also contributed. Clothing, or its frictional interaction with human skin, was demonstrated to be a source of coarse particles, and especially of the highly fluorescent fraction. Emission rates of FBAPs previously reported for lecture classes were well bounded by the experimental results obtained in this chamber study. In both settings, the size distribution of occupant FBAP emissions had a dominant mode in the 3-5 μm diameter range.

  4. Time-resolved analysis of particle emissions from residential biomass combustion - Emissions of refractory black carbon, PAHs and organic tracers

    Science.gov (United States)

    Nielsen, Ingeborg E.; Eriksson, Axel C.; Lindgren, Robert; Martinsson, Johan; Nyström, Robin; Nordin, Erik Z.; Sadiktsis, Ioannis; Boman, Christoffer; Nøjgaard, Jacob K.; Pagels, Joakim

    2017-09-01

    Time-resolved particle emissions from a conventional wood stove were investigated with aerosol mass spectrometry to provide links between combustion conditions, emission factors, mixing state of refractory black carbon and implications for organic tracer methods. The addition of a new batch of fuel results in low temperature pyrolysis as the fuel heats up, resulting in strong, short-lived, variable emission peaks of organic aerosol-containing markers of anhydrous sugars, such as levoglucosan (fragment at m/z 60). Flaming combustion results in emissions dominated by refractory black carbon co-emitted with minor fractions of organic aerosol and markers of anhydrous sugars. Full cycle emissions are an external mixture of larger organic aerosol-dominated and smaller thinly coated refractory black carbon particles. A very high burn rate results in increased full cycle mass emission factors of 66, 2.7, 2.8 and 1.3 for particulate polycyclic aromatic hydrocarbons, refractory black carbon, total organic aerosol and m/z 60, respectively, compared to nominal burn rate. Polycyclic aromatic hydrocarbons are primarily associated with refractory black carbon-containing particles. We hypothesize that at very high burn rates, the central parts of the combustion zone become air starved, leading to a locally reduced combustion temperature that reduces the conversion rates from polycyclic aromatic hydrocarbons to refractory black carbon. This facilitates a strong increase of polycyclic aromatic hydrocarbons emissions. At nominal burn rates, full cycle emissions based on m/z 60 correlate well with organic aerosol, refractory black carbon and particulate matter. However, at higher burn rates, m/z 60 does not correlate with increased emissions of polycyclic aromatic hydrocarbons, refractory black carbon and organic aerosol in the flaming phase. The new knowledge can be used to advance source apportionment studies, reduce emissions of genotoxic compounds and model the climate impacts of

  5. [Research on NEDC ultrafine particle emission characters of a port fuel injection gasoline car].

    Science.gov (United States)

    Hu, Zhi-Yuan; Li, Jin; Tan, Pi-Qiang; Lou, Di-Ming

    2012-12-01

    A Santana gasoline car with multi-port fuel injection (PFI) system was used as the research prototype and an engine exhaust particle sizer (EEPS) was employed to investigate the exhaust ultrafine particle number and size distribution characters of the tested vehicle in new European driving cycle (NEDC). The tested results showed that the vehicle's nuclear particle number, accumulation particle number, as well as the total particle number emission increased when the car drove in accelerated passage, and the vehicle's particle number emission was high during the first 40 seconds after test started and when the speed was over 90 km x h(-1) in extra urban driving cycle (EUDC) in NEDC. The ultrafine particle distribution of the whole NEDC showed a single peak logarithmic distribution, with diameters of the peak particle number emission ranging from 10 nm to 30 nm, and the geometric mean diameter was 24 nm. The ultrafine particle distribution of the urban driving cycle named by the economic commission for Europe (ECE) e. g. ECE I, ECE II - IV, the extra urban driving cycle e. g. EUDC, and the idling, constant speed, acceleration, deceleration operation conditions of NEDC all showed a single peak logarithmic distribution, also with particle diameters of the peak particle number emission ranging from 10 nm to 30 nm, and the geometric mean diameters of different driving cycle and different driving mode were from 14 nm to 42 nm. Therefore, the ultrafine particle emissions of the tested PFI gasoline car were mainly consisted of nuclear mode particles with a diameter of less than 50 nm.

  6. Frozen Hydrocarbon Particles of Cometary Halos as Carriers of Unidentified Emissions

    Indian Academy of Sciences (India)

    Irakli Simonia

    2005-12-01

    The possible nature of unidentified cometary emissions is under discussion. We propose a new model of the ice particles in cometary halos as a mixture of frozen polycyclic aromatic hydrocarbons and acyclic hydrocarbons.We describe principal properties of frozen hydrocarbon particles (FHPs) and suggest interpreting some of the unidentified cometary emission lines as the photoluminescence of FHPs. The results of comparative analysis are present.

  7. In-Situ Characteristics of Particle Emissions from Biomass Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Pagels, Joakum; Wierzbicka, Aneta; Bohgard, Mats [Lund Univ. (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Bioenergy Technology; Swietlicki, Erik [Lund Univ. (Sweden). Div. of Nuclear Physics

    2005-07-01

    In this work we used a Scanning Mobility Particle Sizer and an Electrical Low-pressure Impactor to: a) Derive information of the particle morphology through air-borne analysis and b) Identify time and size variations of particle phase components from incomplete combustion and ash-components. The results presented here covers measurements in two moving grate boilers (12 MW operating on moist forest residue and 1.5 MW operating on wood pellets). We have previously shown that PM1 estimated from Electrical Low-Pressure Impactor (ELPI)-measurements consisted of a rather constant background with peaks correlating with CO and OGC peaks. In the 1.5 MW boiler EC contributed to 34% of PM1, while in the 12 MW boiler EC was below 0.5%. Figure 2 shows time variations in the 1.5 MW boiler as the current in three stages of the ELPI-impactor. Note that time-variations increase strongly with particle size. The fraction of the gravimetric mass detected as water-soluble ions (IC) decreased from {approx} 70% for dae= 78 and 133 nm to {approx} 25% for 322 and 510 nm particles and increased to around 50% for particles larger than 1 {mu}m. In the 12 MW boiler time variations were as low as for 128 nm particles and IC recovery was high for all studied particle sizes. Based on these data we conclude that PM consisting of ash-components are formed with small time variations mainly in mobility-sizes below 250 nm, while Elemental Carbon is emitted at high concentrations during peaks on the time-scale 10-30 s, mainly in particle sizes larger than 150 nm. However, the detailed mixing status of these two particle types/materials is still not known.

  8. Ion-Induced Emission of Charged Particles from Solid Hydrogen and Deuterium

    DEFF Research Database (Denmark)

    Børgesen, P.; Schou, Jørgen; Sørensen, H.

    1980-01-01

    Measurements have been made of the emission of both positive and negative particles from solid hydrogen and deuterium for normal incidence of H+, H2+, H+3, D2H+, D3+ and He+ ions up to 10 keV. For positive particles the emission coefficient increased with increasing energy of incidence to reach...... a value of 0.08 per atom for 10 keV H+ onto hydrogen. Apparently the positive particles are sputtered ones. The negative particles emitted are predominantly electrons. The emission coefficient per incident atom as a function of the velocity of the incident particle agrees fairly well with results...... published earlier for incidence of hydrogen and deuterium ions. However, systematic differences of up to 10% are now observed between the coefficients for the different types of ions....

  9. Direct measurement of particle formation and growth from the oxidation of biogenic emissions

    Directory of Open Access Journals (Sweden)

    T. M. VanReken

    2006-01-01

    Full Text Available A new facility has been developed to investigate the formation of new particles from the oxidation of volatile organic compounds emitted from vegetation. The facility consists of a biogenic emissions enclosure, an aerosol growth chamber, and the associated instrumentation. Using the facility, new particle formation events have been induced through the reaction of ozone with three different precursor gas mixtures: an α-pinene test mixture and the emissions of a Holm oak (Quercus ilex specimen and a loblolly pine (Pinus taeda specimen. The results demonstrate the variability between species in their potential to form new aerosol products. The emissions of Q. ilex specimen resulted in fewer particles than did α-pinene, although the concentration of monoterpenes was roughly equal in both experiments before the addition of ozone. Conversely, the oxidation of P. taeda specimen emissions led to the formation of more particles than either of the other two gas mixtures, despite a lower initial terpenoid concentration. These variations can be attributed to differences in the speciation of the vegetative emissions with respect to the α-pinene mixture and to each other. Specifically, the presence of β-pinene and other slower-reacting monoterpenes probably inhibited particle formation in the Q. ilex experiment, while the presence of sesquiterpenes, including β-caryophyllene, in the emissions of the P. taeda specimen were the likely cause of the more intense particle formation events observed during that experiment.

  10. Transformation optics and invisibility cloaks

    DEFF Research Database (Denmark)

    Qiu, Min; Yan, Min; Yan, Wei

    2008-01-01

    In this paper, we briefly summarize the theory of transformation optics and introduce its application in achieving perfect invisibility cloaking. In particular, we theoretically show how the task of realizing cylindrical invisibility cloaks can be eased by using either structural approximation...

  11. Chemical characterization of the fine particle emissions from commercial aircraft engines during the Aircraft Particle Emissions eXperiment (APEX) 1 to 3

    Science.gov (United States)

    This paper addresses the need for detailed chemical information on the fine particulate matter (PM2.5) generated by commercial aviation engines. The exhaust plumes of nine engine models were sampled during the three test campaigns of the Aircraft Particle Emissions eXperiment (AP...

  12. Refinement of the Compton–Rayleigh scatter ratio method for use on the Mars Science Laboratory alpha particle X-ray spectrometer: II – Extraction of invisible element content

    Energy Technology Data Exchange (ETDEWEB)

    Perrett, Glynis M. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Campbell, John L., E-mail: icampbel@uoguelph.ca [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Gellert, Ralf [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); King, Penelope L. [Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 (Australia); Nield, Emily; O’Meara, Joanne M.; Pradler, Irina [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada)

    2016-02-01

    The intensity ratio C/R between Compton and Rayleigh scatter peaks of the exciting Pu L X-rays in the alpha particle X-ray spectrometer (APXS) is strongly affected by the presence of very light elements such as oxygen which cannot be detected directly by the APXS. C/R values are determined along with element concentrations by fitting APXS spectra of geochemical reference materials (GRMs) with the GUAPX code. A quantity K is defined as the ratio between the C/R value determined by Monte Carlo simulation based on the measured element concentrations and the fitted C/R value from the spectrum. To ensure optimally accurate K values, the choice of appropriate GRMs is explored in detail, with attention paid to Rb and Sr, whose characteristic Kα X-ray peaks overlap the Pu Lα scatter peaks. The resulting relationship between the ratio K and the overall oxygen fraction is linear. This provides a calibration from which the concentration of additional light invisible constituents (ALICs) such as water may be estimated in unknown rock and conglomerate samples. Several GRMs are used as ‘unknowns’ in order to evaluate the accuracy of ALIC concentrations derived in this manner.

  13. Particle and gas emissions from a simulated coal-burning household fire pit

    Energy Technology Data Exchange (ETDEWEB)

    Linwei Tian; Donald Lucas; Susan L. Fischer; S. C. Lee; S. Katharine Hammond; Catherine P. Koshland [University of California, Berkeley, CA (United States). School of Public Health

    2008-04-01

    An open fire was assembled with firebricks to simulate the household fire pit used in rural China, and 15 different coals from this area were burned to measure the gaseous and particulate emissions. Particle size distribution was studied with a microorifice uniform-deposit impactor (MOUDI). Over 90% of the particulate mass was attributed to sub-micrometer particles. The carbon balance method was used to calculate the emission factors. Emission factors for four pollutants (particulate matter, CO{sub 2}, total hydrocarbons, and NOx) were 2-4 times higher for bituminous coals than for anthracites. In past inventories of carbonaceous emissions used for climate modeling, these two types of coal were not treated separately. The dramatic emission factor difference between the two types of coal warrants attention in the future development of emission inventories. 25 refs., 8 figs., 1 tab.

  14. News on $\\beta$-delayed particle emission from $^{14}$Be

    CERN Document Server

    Jeppesen, H; Borge, M J G; Cederkäll, J; Fynbo, H O U; Fedoseyev, V N; Hansper, V Y; Jonson, B; Markenroth, K; Mishin, V I; Nilsson, T; Nyman, G; Riisager, K; Tengblad, O; Wilhelmsen Rolander, K

    2002-01-01

    $\\beta$-delayed charged particles from $^{14}$Be have been measured and give an upper limit on $\\beta$-delayed $\\alpha$-particles of B($\\beta\\alpha$) < $\\,6.7\\times\\!10^{-5}$ and a tentative branching ratio on $\\beta$-delayed tritons of $7.5\\times\\!10^{-5}$ < B($\\beta$t) < $\\,3.9\\times\\!10^{-4}$. We combine the knowledge on $\\beta$-delayed particles from $^{14}$Be to deduce information on the $\\beta$-strength distribution.

  15. Search for charged-particle emission from deuterated palladium foils

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, K.D.; Gippner, P.; Seidel, W.; Stary, F.; Wohlfarth, D. (Zentralinstitut fuer Kernforschung, Rossendorf bei Dresden (German Democratic Republic))

    1990-05-01

    Results are presented from the search for energetic charged particles possibly emitted from a deuterium loaded palladium electrode in an electrolysis cell. Within the sensitivity of our experimental set-up, we could not find events originating from 'cold nuclear fusion' processes. Based on this outcome, an upper limit for the non-observation of CNF of 2.0x10{sup -2}s{sup -1} emitted charged particles per cm{sup 3} (Pd) resp. 1.6x10{sup -24}s{sup -1} emitted charged particles per D pair has been deduced. (orig.).

  16. Characterization of Gas and Particle Emissions from Laboratory Burns of Peat

    Science.gov (United States)

    Peat cores collected from two locations in eastern North Carolina (NC, USA) were burned in a laboratory facility to characterize emissions during simulated field combustion. Particle and gas samples were analyzed to quantify emission factors for particulate matter (PM2.5), organi...

  17. Influence of Shell on Pre-scission Particle Emission of a Doubly Magic Nucleus 208Pb

    Institute of Scientific and Technical Information of China (English)

    YE Wei

    2004-01-01

    Using Smoluchowski equation, we study the shell effects on the emission of light particles in the fission process of a doubly magic nucleus 208 pb. Calculated results show that shell has a considerable effect on the neutron emission and that shell effect gradually becomes weak with increasing excitation energy. In addition, a dependence of shell effects in the neutron emission on the angular momentum has been found.

  18. Characterisation of particle emissions from the driving car fleet and the contribution to ambient and indoor particle concentrations

    Science.gov (United States)

    Palmgren, Finn; Wåhlin, Peter; Kildesø, Jan; Afshari, Alireza; Fogh, Christian L.

    The population is mainly exposed to high air pollution concentrations in the urban environment, where motor vehicle emissions constitute the main source of fine and ultrafine particles. These particles can penetrate deep into the respiratory system, and studies indicate that the smaller the particle, the larger the health impacts. The chemical composition, surface reactivity and physical properties are also important. However, the knowledge about chemical and physical properties of particles and the temporal and spatial variability of the smallest particles is still very limited. The present study summarises the first results of a larger project with the aims to improve the knowledge. The concentration and the emissions of ultrafine particles from petrol and diesel vehicles, respectively, have been quantified using Scanning Mobility Particle Sizer of ultrafine particles in the size range 6-700 nm and routine monitoring data from urban streets and urban background in Denmark. The quantification was carried out using receptor modelling. The number size distributions of petrol and diesel emissions showed a maximum at 20-30 nm and non-traffic at ≈100 nm. The contribution of ultrafine particles from diesel vehicles is dominating in streets. The same technique has been applied on PM 10, and ≈50% contribution from non-traffic. The technique has also been introduced in relation to elemental and organic carbon, and the first data showed strong correlation between traffic pollution and elemental carbon. The outdoor air quality has a significant effect on indoor pollution levels, and we spend most of the time indoors. Knowledge about the influence of ambient air pollution on the concentrations in the indoor environment is therefore crucial for assessment of human health effects of traffic pollution. The results of our studies will be included in air quality models for calculation of human exposure. Preliminary results from our first campaign showed, that the deposition

  19. Crowding by invisible flankers.

    Directory of Open Access Journals (Sweden)

    Cristy Ho

    Full Text Available BACKGROUND: Human object recognition degrades sharply as the target object moves from central vision into peripheral vision. In particular, one's ability to recognize a peripheral target is severely impaired by the presence of flanking objects, a phenomenon known as visual crowding. Recent studies on how visual awareness of flanker existence influences crowding had shown mixed results. More importantly, it is not known whether conscious awareness of the existence of both the target and flankers are necessary for crowding to occur. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that crowding persists even when people are completely unaware of the flankers, which are rendered invisible through the continuous flash suppression technique. Contrast threshold for identifying the orientation of a grating pattern was elevated in the flanked condition, even when the subjects reported that they were unaware of the perceptually suppressed flankers. Moreover, we find that orientation-specific adaptation is attenuated by flankers even when both the target and flankers are invisible. CONCLUSIONS: These findings complement the suggested correlation between crowding and visual awareness. What's more, our results demonstrate that conscious awareness and attention are not prerequisite for crowding.

  20. Emission of ultrafine particles from the incineration of municipal solid waste: A review

    Science.gov (United States)

    Jones, Alan M.; Harrison, Roy M.

    2016-09-01

    Ultrafine particles (diameter waste, and this article reviews studies carried out on the emissions from modern municipal waste incinerators. The effects of engineering controls upon particle emissions are considered, as well as the very limited information on the effects of changing waste composition. The results of measurements of incinerator flue gas, and of atmospheric sampling at ground level in the vicinity of incinerators, show that typical ultrafine particle concentrations in flue gas are broadly similar to those in urban air and that consequently, after the dispersion process dilutes incinerator exhaust with ambient air, ultrafine particle concentrations are typically indistinguishable from those that would occur in the absence of the incinerator. In some cases the ultrafine particle concentration in the flue gas may be below that in the local ambient air. This appears to be a consequence of the removal of semi-volatile vapours in the secondary combustion zone and abatement plant, and the high efficiency of fabric filters for ultrafine particle collection.

  1. Light charged particle emission in heavy-ion reactions – What have we learnt?

    Indian Academy of Sciences (India)

    S Kailas

    2001-07-01

    Light charged particles emitted in heavy-ion induced reactions, their spectra and angular distributions measured over a range of energies, carry the signature of the underlying reaction mechanisms. Analysis of data of light charged particles, both inclusive and exclusive measured in coincidence with gamma rays, fission products, evaporation residues have yielded interesting results which bring out the influence of nuclear structure, nuclear mean field and dynamics on the emission of these particles.

  2. Assessment of exhaust emissions from carbon nanotube production and particle collection by sampling filters.

    Science.gov (United States)

    Tsai, Candace Su-Jung; Hofmann, Mario; Hallock, Marilyn; Ellenbecker, Michael; Kong, Jing

    2015-11-01

    This study performed a workplace evaluation of emission control using available air sampling filters and characterized the emitted particles captured in filters. Characterized particles were contained in the exhaust gas released from carbon nanotube (CNT) synthesis using chemical vapor deposition (CVD). Emitted nanoparticles were collected on grids to be analyzed using transmission electron microscopy (TEM). CNT clusters in the exhaust gas were collected on filters for investigation. Three types of filters, including Nalgene surfactant-free cellulose acetate (SFCA), Pall A/E glass fiber, and Whatman QMA quartz filters, were evaluated as emission control measures, and particles deposited in the filters were characterized using scanning transmission electron microscopy (STEM) to further understand the nature of particles emitted from this CNT production. STEM analysis for collected particles on filters found that particles deposited on filter fibers had a similar morphology on all three filters, that is, hydrophobic agglomerates forming circular beaded clusters on hydrophilic filter fibers on the collecting side of the filter. CNT agglomerates were found trapped underneath the filter surface. The particle agglomerates consisted mostly of elemental carbon regardless of the shapes. Most particles were trapped in filters and no particles were found in the exhaust downstream from A/E and quartz filters, while a few nanometer-sized and submicrometer-sized individual particles and filament agglomerates were found downstream from the SFCA filter. The number concentration of particles with diameters from 5 nm to 20 µm was measured while collecting particles on grids at the exhaust piping. Total number concentration was reduced from an average of 88,500 to 700 particle/cm(3) for the lowest found for all filters used. Overall, the quartz filter showed the most consistent and highest particle reduction control, and exhaust particles containing nanotubes were successfully

  3. β-delayed Multi-particle Emission From 31Ar

    Institute of Scientific and Technical Information of China (English)

    A. A. Ciemny; J. Du´enas-Daz; V. Dunin; J. M. Espino; A. Estrade; F. Farinon; A. Fomichev; H. Geisse; A. Gorshkov; G. Kami´nski; O. Kiselev; C. Mazzocchi; R. Kn¨obe; S. Krupko; M. Kuich; Yu. A. Litvinov; G. Marquinez-Dur´an; I. Martel; I. Mukha; C. Nociforo; A. K. Ord´uz; S. Pietri; W. Dominik; A. Prochazka; A. M. S´anchez-Ben´ıtez; H. Simon; B. Sitar; R. Slepnev; M. Stanoiu; P. Strmen; I. Szarka; M. Takechi; Y. Tanaka; Z. Janas; H. Weick; J. S. Winfield; M. Pf¨utzner; M. Pomorski; L. Acosta; S. Baraeva; E. Casarejos

    2016-01-01

    The β+ decay of 31Ar was investigated in an experiment at the GSI-FRS spectrometer. The ions of interest have been produced in the fragmentation of a 36Ar beam at 880 MeV/nucleon and implanted in a time projection chamber with optical readout. In addition to β-delayed one and two proton emission, for the first time the emission ofβ-delayed 3 protons has been observed. The branching ratio for this decay mode is found to be (0.07 ± 0.02)%.

  4. Emission of submicron aerosol particles in cement kilns: Total concentration and size distribution.

    Science.gov (United States)

    Rotatori, Mauro; Mosca, Silvia; Guerriero, Ettore; Febo, Antonio; Giusto, Marco; Montagnoli, Mauro; Bianchini, Massimo; Ferrero, Renato

    2015-01-01

    Cement plants are responsible for particle and gaseous emissions into the atmosphere. With respect to particle emission, the greater part of is in the range from 0.05 to 5.0 µm in diameter. In the last years attention was paid to submicron particles, but there is a lack of available data on the emission from stationary sources. In this paper, concentration and size distribution of particles emitted from four cement kilns, in relationship to operational conditions (especially the use of alternative fuel to coal) of the clinker process are reported. Experimental campaigns were carried out by measuring particles concentration and size distribution at the stack of four cement plants through condensation particle counter (CPC) and scanning mobility particle sizer spectrometer (SMPS). Average total particle number concentrations were between 2000 and 4000 particles/cm³, about 8-10 times lower that those found in the corresponding surrounding areas. As for size distribution, for all the investigated plants it is stable with a unimodal distribution (120-150 nm), independent from the fuel used.

  5. Susceptibility of contrail ice crystal numbers to aircraft soot particle emissions

    Science.gov (United States)

    Kärcher, B.; Voigt, C.

    2017-08-01

    We develop an idealized, physically based model describing combined effects of ice nucleation and sublimation on ice crystal number during persistent contrail formation. Our study represents the first effort to predict ice numbers at the point where contrails transition into contrail cirrus—several minutes past formation—by connecting them to aircraft soot particle emissions and atmospheric supersaturation with respect to ice. Results averaged over an observed exponential distribution of ice supersaturation (mean value 15%) indicate that large reductions in soot particle numbers are needed to lower contrail ice crystal numbers significantly for soot emission indices around 1015 (kg fuel)-1, because reductions in nucleated ice number are partially compensated by sublimation losses. Variations in soot particle (-50%) and water vapor (+10%) emission indices at threefold lower soot emissions resulting from biofuel blending cause ice crystal numbers to change by -35% and climate impact of aviation.

  6. The influence of design and fuel parameters on the particle emissions from wood pellets combustion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wiinikka, Henrik; Gebart, Rikard [Energy Technology Centre, Piteaa (Sweden)

    2005-02-01

    Combustion of solid biomass under fixed bed conditions is a common technique to generate heat and power in both small and large scale grate furnaces (domestic boilers, stoves, district heating plants). Unfortunately, combustion of biomass will generate particle emissions containing both large fly ash particles and fine particles that consist of fly ash and soot. The large fly ash particles have been produced from fusion of non-volatile ash-forming species in burning char particle. The inorganic fine particles have been produced from nucleation of volatilised ash elements (K, Na, S, Cl and Zn). If the combustion is incomplete, soot particles are also produced from secondary reaction of tar. The particles in the fine fraction grows by coagulation and coalescence to a particle diameter around 0.1 pm. Since the smallest particles are very hard to collect in ordinary cleaning devices they contribute to the ambient air pollution. Furthermore, fine airborne particles have been correlated to adverse effects on the human health. It is therefore essential to minimize particle formation from the combustion process and thereby reduce the emissions of particulates to the ambient air. The aim with this project is to study particle emissions from small scale combustion of wood pellets and to investigate the impact of different operating, construction and fuel parameters on the amount and characteristic of the combustion generated particles. To address these issues, experiments were carried out in a 10 kW updraft fired wood pellets reactor that has been custom designed for systematic investigations of particle emissions. In the flue gas stack, particle emissions were sampled on a filter. The particle mass and number size distributions were analysed by a low pressure cascade impactor and a SMPS (Scanning Electron Mobility Particle Sizer). The results showed that the temperature and the flow pattern in the combustion zone affect the particle emissions. Increasing combustion

  7. SLAC T-510: Radio emission from particle cascades in the presence of a magnetic field

    Science.gov (United States)

    Mulrey, Katharine

    2017-03-01

    Cosmic ray induced particle cascades radiate in radio frequencies in the Earth's atmosphere. Geomagnetic and Askaryan emission provide an effective way to detect ultra-high energy cosmic rays. The SLAC T-510 experiment was the first to measure magnetically induced radiation from particle cascades in a controlled laboratory setting. An electron beam incident upon a dense dielectric target produced a particle cascade in the presence of a variable magnetic field. Antennas covering a band of 30-3000 MHz sampled RF emission in vertical and horizontal polarizations. Results from T-510 are compared to particle-level RF-emission simulations which are critical for reconstructing the energy and composition of detected ultra-high energy cosmic ray air showers. We discuss the experimental set up, the data processing, the systematic errors and the main results of the experiment, which we found in a good agreement with the simulations.

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

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2010-06-01

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

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

    log10F=0.47·U+2.26

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

  9. Particle emissions from microalgae biodiesel combustion and their relative oxidative potential.

    Science.gov (United States)

    Rahman, M M; Stevanovic, S; Islam, M A; Heimann, K; Nabi, M N; Thomas, G; Feng, B; Brown, R J; Ristovski, Z D

    2015-09-01

    Microalgae are considered to be one of the most viable biodiesel feedstocks for the future due to their potential for providing economical, sustainable and cleaner alternatives to petroleum diesel. This study investigated the particle emissions from a commercially cultured microalgae and higher plant biodiesels at different blending ratios. With a high amount of long carbon chain lengths fatty acid methyl esters (C20 to C22), the microalgal biodiesel used had a vastly different average carbon chain length and level of unsaturation to conventional biodiesel, which significantly influenced particle emissions. Smaller blend percentages showed a larger reduction in particle emission than blend percentages of over 20%. This was due to the formation of a significant nucleation mode for the higher blends. In addition measurements of reactive oxygen species (ROS), showed that the oxidative potential of particles emitted from the microalgal biodiesel combustion were lower than that of regular diesel. Biodiesel oxygen content was less effective in suppressing particle emissions for biodiesels containing a high amount of polyunsaturated C20-C22 fatty acid methyl esters and generated significantly increased nucleation mode particle emissions. The observed increase in nucleation mode particle emission is postulated to be caused by very low volatility, high boiling point and high density, viscosity and surface tension of the microalgal biodiesel tested here. Therefore, in order to achieve similar PM (particulate matter) emission benefits for microalgal biodiesel likewise to conventional biodiesel, fatty acid methyl esters (FAMEs) with high amounts of polyunsaturated long-chain fatty acids (≥C20) may not be desirable in microalgal biodiesel composition.

  10. [Experimental study on the size spectra and emission factor of ultrafine particle from coal combustion].

    Science.gov (United States)

    Sun, Zai; Yang, Wen-jun; Xie, Xiao-fang; Chen, Qiu-fang; Cai, Zhi-liang

    2014-12-01

    The emission characteristics of ultrafine particles released from pulverized coal combustion were studied, the size spectra of ultrafine particles (5.6-560 nm) were measured with FMPS (fast mobility particle sizer) on a self-built aerosol experiment platform. Meanwhile, a particle dynamic evolution model was established to obtain the particle deposition rate and the emission rate through the optimized algorithm. Finally, the emission factor was calculated. The results showed that at the beginning of particle generation, the size spectra were polydisperse and complex, the initial size spectra was mainly composed of three modes including 10 nm, 30-40 nm and 100-200 nm. Among them, the number concentration of mode around 10 nm was higher than those of other modes, the size spectrum of around 100-200 nm was lognormal distributed, with a CMD (count median diameter) of around 16 nm. Then, as time went on, the total number concentration was decayed by exponential law, the CMD first increased and then tended to be stable gradually. The calculation results showed that the emission factor of particles from coal combustion under laboratory condition was (5.54 x 10(12) ± 2.18 x 10(12)) unit x g(-1).

  11. Experimental validation of granular dynamics simulations of gas-fluidised beds with homogeneous inflow conditions using Positron Emission Particle Tracking

    NARCIS (Netherlands)

    Hoomans, B.P.B.; Kuipers, J.A.M.; Mohd Salleh, M.; Seville, J.P.

    2001-01-01

    A hard-sphere granular dynamics model of a two-dimensional gas-fluidised bed was experimentally validated using Positron Emission Particle Tracking (PEPT). In the model the Newtonian equations of motion are solved for each solid particle while taking into account the particle¿particle and particle¿w

  12. Emissions of NOx, particle mass and particle numbers from aircraft main engines, APU's and handling equipment at Copenhagen Airport

    Science.gov (United States)

    Winther, Morten; Kousgaard, Uffe; Ellermann, Thomas; Massling, Andreas; Nøjgaard, Jacob Klenø; Ketzel, Matthias

    2015-01-01

    This paper presents a detailed emission inventory for NOx, particle mass (PM) and particle numbers (PN) for aircraft main engines, APU's and handling equipment at Copenhagen Airport (CPH) based on time specific activity data and representative emission factors for the airport. The inventory has a high spatial resolution of 5 m × 5 m in order to be suited for further air quality dispersion calculations. Results are shown for the entire airport and for a section of the airport apron area ("inner apron") in focus. The methodology presented in this paper can be used to quantify the emissions from aircraft main engines, APU and handling equipment in other airports. For the entire airport, aircraft main engines is the largest source of fuel consumption (93%), NOx, (87%), PM (61%) and PN (95%). The calculated fuel consumption [NOx, PM, PN] shares for APU's and handling equipment are 5% [4%, 8%, 5%] and 2% [9%, 31%, 0%], respectively. At the inner apron area for handling equipment the share of fuel consumption [NOx, PM, PN] are 24% [63%, 75%, 2%], whereas APU and main engines shares are 43% [25%, 19%, 54%], and 33% [11%, 6%, 43%], respectively. The inner apron NOx and PM emission levels are high for handling equipment due to high emission factors for the diesel fuelled handling equipment and small for aircraft main engines due to small idle-power emission factors. Handling equipment is however a small PN source due to the low number based emission factors. Jet fuel sulphur-PM sensitivity calculations made in this study with the ICAO FOA3.0 method suggest that more than half of the PM emissions from aircraft main engines at CPH originate from the sulphur content of the fuel used at the airport. Aircraft main engine PN emissions are very sensitive to the underlying assumptions. Replacing this study's literature based average emission factors with "high" and "low" emission factors from the literature, the aircraft main engine PN emissions were estimated to change with a

  13. Making Invisible Forces Visible

    DEFF Research Database (Denmark)

    Ratner, Helene; Pors, Justine Grønbæk

    2013-01-01

    This paper investigates managerial tactics of visualisation when a need to know and manage employees' values and attitudes is expressed. Using the Danish public school as a case study, we explore how school managers use teachers' emotions to render visible presumably invisible information about...... their 'true' attitudes and values. The paper draws on theories of affect as well as actor-network theory to analyse three incidents where managers turn their interpretations of teachers' emotions into such information. These incidents suggest that the efforts to render employees' attitudes and values visible...... install a normative emotional scale where an ideal employee displays emotional investment and self-control. This has implications, not only for employees who are expected to exhibit the 'right' emotions, but also for management, which comes to depend on transient emotions and co-presence in situations...

  14. The Invisible Boy

    DEFF Research Database (Denmark)

    Perry, Kevin Anthony; Jensen, Iben

    , either in or outside school. The question about how a group of students can collectively forget that one student is isolated in the class must be raised. The aim of this thinking note is to explore the mechanisms around social stigma and attempt to shed more light on the issue surrounding the ‘invisible...... “strategic representation” — arguing for (and discussing) the strategic and financial advantages of representation. It introduces the quantitative studies from the US and DK, that show that better representation may be economically strategical. The challenges of these arguments will also be discussed...... Interview in Media Production Studies.”Advancing Media Production Research: Shifting Sites, Methods, and Politics (2015): 131. Bonilla-Silva, E., (2006). The Strange Enigma of Race in Contemporary America in: Racism Without Racist...

  15. Detection of Bioaerosols using Single Particle Thermal Emission Spectroscopy

    Science.gov (United States)

    2013-03-01

    droplets was accomplished by using a peristaltic pump to inject a set flow-rate of liquid mineral oil into a heated hypodermic needle . Heated mineral...heated to temperatures in excess of a 100 °C. Prevailing theory suggests a strong link between thermal emission and absorption spectra for bulk...iv 1. Background 1 2. Theory 1 3. Experiment 5 4. Results 13 5. Conclusion 16 6. References 18 List of Symbols, Abbreviations, and Acronyms 20

  16. Invisible 'glue' bosons in model field theory

    CERN Document Server

    Shirokov, M I

    2002-01-01

    Fermionic psi(x) and bosonic phi(x) fields with vector coupling are discussed. It is shown that 'clothed' bosons of the model do not interact with fermions and between themselves. If phi(x) does not interact with other fields of the particle physics, then the 'clothed' bosons have properties of the cosmological 'dark' matter': they cannot be detected in Earth's laboratories. This cause of the boson invisibility contrasts with the origin of the unobservability of the isolated gluons in QCD which is explained by the confinement of colour

  17. (In)visible Z' and dark matter

    CERN Document Server

    Dudas, E; Pokorski, S; Romagnoni, A

    2009-01-01

    We study the consequences of an extension of the standard model containing an invisible extra gauge group under which the SM particles are neutral. We show that effective operators, generated by loops of heavy chiral fermions charged undervboth gauge groups and connecting the new gauge sector to the Standard Model, can give rise to a viable dark matter candidate. Its annihilations produce clean visible signals through a gamma-ray line. This would be a smoking gun signature of such models observable by actual experiments.

  18. Particle and carbon dioxide emissions from passenger vehicles operating on unleaded petrol and LPG fuel.

    Science.gov (United States)

    Ristovski, Z D; Jayaratne, E R; Morawska, L; Ayoko, G A; Lim, M

    2005-06-01

    A comprehensive study of the particle and carbon dioxide emissions from a fleet of six dedicated liquefied petroleum gas (LPG) powered and five unleaded petrol (ULP) powered new Ford Falcon Forte passenger vehicles was carried out on a chassis dynamometer at four different vehicle speeds--0 (idle), 40, 60, 80 and 100 km h(-1). Emission factors and their relative values between the two fuel types together with a statistical significance for any difference were estimated for each parameter. In general, LPG was found to be a 'cleaner' fuel, although in most cases, the differences were not statistically significant owing to the large variations between emissions from different vehicles. The particle number emission factors ranged from 10(11) to 10(13) km(-1) and was over 70% less with LPG compared to ULP. Corresponding differences in particle mass emission factor between the two fuels were small and ranged from the order of 10 microg km(-1) at 40 to about 1000 microg km(-1) at 100 km h(-1). The count median particle diameter (CMD) ranged from 20 to 35 nm and was larger with LPG than with ULP in all modes except the idle mode. Carbon dioxide emission factors ranged from about 300 to 400 g km(-1) at 40 km h(-1), falling with increasing speed to about 200 g km(-1) at 100 km h(-1). At all speeds, the values were 10% to 18% greater with ULP than with LPG.

  19. Improved field emission performance of carbon nanotube by introducing copper metallic particles

    Directory of Open Access Journals (Sweden)

    Chen Yiren

    2011-01-01

    Full Text Available Abstract To improve the field emission performance of carbon nanotubes (CNTs, a simple and low-cost method was adopted in this article. We introduced copper particles for decorating the CNTs so as to form copper particle-CNT composites. The composites were fabricated by electrophoretic deposition technique which produced copper metallic particles localized on the outer wall of CNTs and deposited them onto indium tin oxide (ITO electrode. The results showed that the conductivity increased from 10-5 to 4 × 10-5 S while the turn-on field was reduced from 3.4 to 2.2 V/μm. Moreover, the field emission current tended to be undiminished after continuous emission for 24 h. The reasons were summarized that introducing copper metallic particles to decorate CNTs could increase the surface roughness of the CNTs which was beneficial to field emission, restrain field emission current from saturating when the applied electric field was above the critical field. In addition, it could also improve the electrical contact by increasing the contact area between CNT and ITO electrode that was beneficial to the electron transport and avoided instable electron emission caused by thermal injury of CNTs.

  20. Improved field emission performance of carbon nanotube by introducing copper metallic particles.

    Science.gov (United States)

    Chen, Yiren; Jiang, Hong; Li, Dabing; Song, Hang; Li, Zhiming; Sun, Xiaojuan; Miao, Guoqing; Zhao, Haifeng

    2011-10-03

    To improve the field emission performance of carbon nanotubes (CNTs), a simple and low-cost method was adopted in this article. We introduced copper particles for decorating the CNTs so as to form copper particle-CNT composites. The composites were fabricated by electrophoretic deposition technique which produced copper metallic particles localized on the outer wall of CNTs and deposited them onto indium tin oxide (ITO) electrode. The results showed that the conductivity increased from 10-5 to 4 × 10-5 S while the turn-on field was reduced from 3.4 to 2.2 V/μm. Moreover, the field emission current tended to be undiminished after continuous emission for 24 h. The reasons were summarized that introducing copper metallic particles to decorate CNTs could increase the surface roughness of the CNTs which was beneficial to field emission, restrain field emission current from saturating when the applied electric field was above the critical field. In addition, it could also improve the electrical contact by increasing the contact area between CNT and ITO electrode that was beneficial to the electron transport and avoided instable electron emission caused by thermal injury of CNTs.

  1. Additive impacts on particle emissions from heating low emitting cooking oils

    Science.gov (United States)

    Amouei Torkmahalleh, M.; Zhao, Y.; Hopke, P. K.; Rossner, A.; Ferro, A. R.

    2013-08-01

    The effect of five additives, including table salt, sea salt, black pepper, garlic powder, and turmeric, on the emission of PM2.5 and ultrafine particles (UFP) from heated cooking oil (200 °C) were studied. One hundred milligrams of the additives were added individually to either canola or soybean oil without stirring. Black pepper, table salt, and sea salt reduced the PM2.5 emission of canola oil by 86% (p oil by 45% (p = 0.003), 52% (p = 0.001), and 53% (p oil. Table salt and sea salt, decreased the level of PM2.5 emissions from soybean oil by 47% (p oil. Black pepper, sea salt, and table salt reduced the total particle number emissions from the soybean oil by 51%, 61% and 68% (p oil with respect to total particle number emissions. Our results indicate that table salt, sea salt, and black pepper can be used to reduce the particle total number and PM2.5 emissions when cooking with oil.

  2. A feature point identification method for positron emission particle tracking with multiple tracers

    Science.gov (United States)

    Wiggins, Cody; Santos, Roque; Ruggles, Arthur

    2017-01-01

    A novel detection algorithm for Positron Emission Particle Tracking (PEPT) with multiple tracers based on optical feature point identification (FPI) methods is presented. This new method, the FPI method, is compared to a previous multiple PEPT method via analyses of experimental and simulated data. The FPI method outperforms the older method in cases of large particle numbers and fine time resolution. Simulated data show the FPI method to be capable of identifying 100 particles at 0.5 mm average spatial error. Detection error is seen to vary with the inverse square root of the number of lines of response (LORs) used for detection and increases as particle separation decreases.

  3. Non-invasive studies of multiphase flow in process equipment. Positron emission particle tracking technique

    Science.gov (United States)

    Balakin, B. V.; Adamsen, T. C. H.; Chang, Y.-F.; Kosinski, P.; Hoffmann, A. C.

    2017-01-01

    Positron emission particle tracking (PEPT) is a novel experimental technique for non-invasive inspection of industrial fluid/particle flows. The method is based on the dynamic positioning of a positron-emitting, flowing object (particle) performed through the sensing of annihilation events and subsequent numerical treatment to determine the particle position. The present paper shows an integrated overview of PEPT studies which were carried out using a new PET scanner in the Bergen University Hospital to study multiphase flows in different geometric configurations.

  4. Positron emission tomography in pebble beds. Part 1: Liquid particle deposition

    Energy Technology Data Exchange (ETDEWEB)

    Barth, T., E-mail: t.barth@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics (IFD), Bautzner Landstraße 400, 01328 Dresden (Germany); Ludwig, M. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics (IFD), Bautzner Landstraße 400, 01328 Dresden (Germany); Kulenkampff, J.; Gründig, M. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology (IRE), Permoserstraße 15, 04318 Leipzig (Germany); Franke, K. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology (IRE), Permoserstraße 15, 04318 Leipzig (Germany); Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmacy (IRP), Permoserstraße 15, 04318 Leipzig (Germany); Lippmann-Pipke, J. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology (IRE), Permoserstraße 15, 04318 Leipzig (Germany); Hampel, U. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics (IFD), Bautzner Landstraße 400, 01328 Dresden (Germany); Helmholtz-Zentrum Dresden-Rossendorf, AREVA Endowed Chair of Imaging Techniques in Energy and Process Engineering, Technische Universität Dresden, 01062 Dresden (Germany)

    2014-02-15

    Highlights: • Particle deposition in a pebble bed was recorded by positron emission tomography. • The particles were radioactively labelled and their spatial distribution was recorded. • Particle deposition was mainly driven by particle inertia and turbulent dispersion. • Particle deposits form hot spots on the upstream face of the single pebbles. - Abstract: Accidental scenarios such as the depressurisation of the primary circuit of high temperature gas cooled pebble bed reactors may lead to the release of fission products via the discharge of radioactive graphite dust. For a detailed source term assessment in such accident scenarios knowledge of the flow mechanics of dust transport in complex coolant circuit components, like pebble beds, recuperator structures and pipe systems is necessary. In this article an experimental study of aerosol deposition in a pebble bed is described. We investigated the deposition of radiolabelled liquid aerosol particles in a scaled pebble bed in an air-driven small-scale aerosol flow test facility under isothermal ambient conditions. The aerosol particles were generated by means of a condensational aerosol generator with potassium-fluoride (KF) condensation nuclei. Particle concentration measurements upstream and downstream of the pebble bed were performed by isokinetic sampling and particle counting. The results agree with typical deposition curves for turbulent and inertia driven particle deposition. Furthermore, positron emission tomography (PET) was performed to visualize and measure particle deposition distributions in the pebble bed. Results of a selected deposition experiment with moderately large particles (d{sub aero} = 3.5 μm, Re{sup ′}{sub pb}=2200) show that the deposited particles are located in the vicinity of the upstream stagnation points of the pebbles. These findings support the thesis that inertia driven particle deposition is predominating.

  5. Influence of moisturizer and relative humidity on human emissions of fluorescent biological aerosol particles.

    Science.gov (United States)

    Zhou, J; Fang, W; Cao, Q; Yang, L; Chang, V W-C; Nazaroff, W W

    2017-05-01

    Utilizing the ultraviolet light-induced fluorescence (UV-LIF) measurement technique as embodied in the Waveband Integrated Bioaerosol Sensor (WIBS-4A), we evaluated the fluorescent particle emissions associated with human shedding while walking in a chamber. The mean emission rates of supermicron (1-10 μm) fluorescent particles were in the range 6.8-7.5 million particles per person-h (~0.3 mg per person-h) across three participants, for conditions when the relative humidity was 60%-70% and no moisturizer was applied after showering. The fluorescent particles displayed a lognormal distribution with the geometric mean diameter in the range 2.5-4 μm and exhibited asymmetry factors that increased with particle size. Use of moisturizer was associated with changes in number and mass emission rates, size distribution, and particle shape. Emission rates were lower when the relative humidity was reduced, but these differences were not statistically significant. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Removal of fine and ultrafine particles from indoor air environments by the unipolar ion emission

    Science.gov (United States)

    Uk Lee, Byung; Yermakov, Mikhail; Grinshpun, Sergey A.

    2004-09-01

    The continuous emission of unipolar ions was evaluated in order to determine its ability to remove fine and ultrafine particles from indoor air environments. The evolution of the indoor aerosol concentration and particle size distribution was measured in real time with the ELPI in a room-size (24.3 m3) test chamber where the ion emitter was operating. After the results were compared with the natural decay, the air cleaning factor was determined. The particle aerodynamic size range of ∼0.04-2 μm was targeted because it represents many bioaerosol agents that cause emerging diseases, as well as those that can be used for biological warfare or in the event of bioterrorism. The particle electric charge distribution (also measured in the test chamber with the ELPI) was rapidly affected by the ion emission. It was concluded that the corona discharge ion emitters (either positive or negative), which are capable of creating an ion density of 105-106 e± cm-3, can be efficient in controlling fine and ultrafine aerosol pollutants in indoor air environments, such as a typical office or residential room. At a high ion emission rate, the particle mobility becomes sufficient so that the particle migration results in their deposition on the walls and other indoor surfaces. Within the tested ranges of the particle size and ion density, the particles were charged primarily due to the diffusion charging mechanism. The particle removal efficiency was not significantly affected by the particle size, while it increased with increasing ion emission rate and the time of emission. The performance characteristics of three commercially available ionic air purifiers, which produce unipolar ions by corona discharge at relatively high emission rates, were evaluated. A 30-minute operation of the most powerful device among those tested resulted in the removal of about 97% of 0.1 μm particles and about 95% of 1 μm particles from the air in addition to the natural decay effect.

  7. Evaluation of particle-induced X-ray emission and particle-induced γ-ray emission of quartz grains for forensic trace sediment analysis.

    Science.gov (United States)

    Bailey, M J; Morgan, R M; Comini, P; Calusi, S; Bull, P A

    2012-03-06

    The independent verification in a forensics context of quartz grain morphological typing by scanning electron microscopy was demonstrated using particle-induced X-ray emission (PIXE) and particle-induced γ-ray emission (PIGE). Surface texture analysis by electron microscopy and high-sensitivity trace element mapping by PIXE and PIGE are independent analytical techniques for identifying the provenance of quartz in sediment samples in forensic investigations. Trace element profiling of the quartz grain matrix separately from the quartz grain inclusions served to differentiate grains of different provenance and indeed went some way toward discriminating between different quartz grain types identified in a single sample of one known forensic provenance. These results confirm the feasibility of independently verifying the provenance of critical samples from forensic cases.

  8. Writing for the Invisible Reader.

    Science.gov (United States)

    Garden, Nancy

    2000-01-01

    Discusses the role of the lesbian writer in addressing the invisibility of teenage readers. Argues that writing about homosexuality is a matter of presenting it rather than promoting it. Includes a review of "The Year they Burned the Books." (NH)

  9. Light Scattering and Thermal Emission by Primitive Dust Particles in Planetary Systems

    CERN Document Server

    Kimura, Hiroshi; Li, Aigen; Lebreton, Jérémy

    2016-01-01

    This review focuses on numerical approaches to deducing the light-scattering and thermal-emission properties of primitive dust particles in planetary systems from astronomical observations. The particles are agglomerates of small grains with sizes comparable to visible wavelength and compositions being mainly magnesium-rich silicates, iron-bearing metals, and organic refractory materials in pristine phases. These unique characteristics of primitive dust particles reflect their formation and evolution around main-sequence stars of essentially solar composition. The development of light-scattering theories has been offering powerful tools to make a thorough investigation of light scattering and thermal emission by primitive dust agglomerates in such a circumstellar environment. In particular, the discrete dipole approximation, the T-matrix method, and effective medium approximations are the most popular techniques for practical use in astronomy. Numerical simulations of light scattering and thermal emission by ...

  10. Preparation and Characterization of Sn-doped ZnO Particles with Low Infrared Emissivity

    Institute of Scientific and Technical Information of China (English)

    赵亮; 朱永平

    2012-01-01

    Sn-doped ZnO particles were successfully synthesized by chemical co-precipitation method.Their morphology,phase,microstructure and infrared emissivity were characterized.The results show that the Sn-doped ZnO particles are of ellipsoid shape,their crystalline structure changed with thermal process temperature,the optimal thermal process temperature and Sn-doped proportion are 1000 ℃ and 15%,respectively,the minimum emissivity values are 0.42,0.28,0.46 and 0.48 corresponding to the infrared wavelengths of 0~∞,3~5,8~14 and 14~20 μm,which indicates that the Sn-doped ZnO particles have the application potential as low infrared emissivity material.

  11. Multi-particle Emission from ${^{31}}$Ar at ISOLDE

    CERN Document Server

    Marroquin, I; Ciemny, A A; de Witte, H; Fraile, L M; Fynbo, H O U; Garzón-Camacho, A; Howard, A; Johansson, H; Jonson, B; Kirsebom, O S; Koldste, G T; Lica, R; Lund, M V; Madurga, M; Mazzocchi, C; Mihai, C; Munch, M; Nae, S A; Nacher, E; Negret, A; Nilsson, T; Perea, A; Refsgaard, J; Riisager, K; Rapisarda, E; Sotty, C; Stanoiu, M; Tengblad, O; Turturica, A E; Vedia, M V

    2016-01-01

    A multi-particle decay experiment was successfully performed at the ISOLDE Decay Station. In this new permanent station, devoted to\\break $\\beta$-decay studies, the novel MAGISOL Si-Plugin Chamber was installed to study the exotic decay modes of the proton drip-line nucleus ${^{31}}$Ar. The motivation was to search for $\\beta3p$ and $\\beta3p\\gamma$ channels, as well as to provide information on resonances in ${^{30}}$S and ${^{29}}$P relevant for the astrophysical\\break rp-process. Description of the experimental set-up and preliminary results are presented.

  12. Measurement and Modeling of Volatile Particle Emissions from Military Aircraft

    Science.gov (United States)

    2011-10-01

    and ion clusters formation in aircraft plumes. Physical Chemistry Chemical Physics, 2004. 6(13): p. 3426-3436. 89 16. Yu, F.Q. and R.P. Turco ...Geophysical Research-Atmospheres, 1998. 103(D20): p. 25915-25934. 17. Yu, F.Q. and R.P. Turco , The role of ions in the formation and evolution of particles...1998. 25(15): p. 2793-2796. 22. Yu, F.Q., R.P. Turco , and B. Karcher, The possible role of organics in the formation and evolution of ultrafine

  13. Regional impacts of ultrafine particle emissions from the surface of the Great Lakes

    Directory of Open Access Journals (Sweden)

    S. H. Chung

    2011-12-01

    Full Text Available Quantifying the impacts of aerosols on climate requires a detailed knowledge of both the anthropogenic and the natural contributions to the aerosol population. Recent work has suggested a previously unrecognized natural source of ultrafine particles resulting from breaking waves at the surface of large freshwater lakes. This work is the first modeling study to investigate the potential for this newly discovered source to affect the aerosol number concentrations on regional scales. Using the WRF-Chem modeling framework, the impacts of wind-driven aerosol production from the surface of the Great Lakes were studied for a July 2004 test case. Simulations were performed for a base case with no lake surface emissions, a case with lake surface emissions included, and a default case wherein large freshwater lakes emit marine particles as if they were oceans. Results indicate that the lake surface emissions can enhance the surface-level aerosol number concentration by ~20% over the remote northern Great Lakes and by ~5% over other parts of the Great Lakes. These results were highly sensitive to the new particle formation (i.e., nucleation parameterization within WRF-Chem; when the new particle formation process was deactivated, surface-layer enhancements from the lake emissions increased to as much as 200%. The results reported here have significant uncertainties associated with the lake emission parameterization and the way ultrafine particles are modeled within WRF-Chem. Nevertheless, the magnitudes of the impacts found in this study suggest that further study to quantify the emissions of ultrafine particles from the surface of the Great Lakes is merited.

  14. Influence of firebed temperature on inorganic particle emissions in a residential wood pellet boiler

    Science.gov (United States)

    Gehrig, Matthias; Jaeger, Dirk; Pelz, Stefan K.; Weissinger, Alexander; Groll, Andreas; Thorwarth, Harald; Haslinger, Walter

    2016-07-01

    The temperature-dependent release of inorganic elements is the first step of the main formation pathway of particle emissions in automatically fired biomass burners. To investigate this step, a residential pellet boiler with an underfeed-burner was equipped with a direct firebed cooling. This test setup enabled decreased firebed temperatures without affecting further parameters like air flow rates or oxygen content in the firebed. A reduction of particle emissions in PM1-fraction at activated firebed cooling was found by impactor measurement and by optical particle counter. The affected particles were found in the size range boiler ash showed no statistically significant differences due to the firebed cooling. Therefore, our results indicate that the direct firebed cooling influenced the release of potassium (K) without affecting other chemical reactions.

  15. Exploring Soot Particle Concentration and Emissivity by Transient Thermocouples Measurements in Laminar Partially Premixed Coflow Flames

    Directory of Open Access Journals (Sweden)

    Gianluigi De Falco

    2017-02-01

    Full Text Available Soot formation in combustion represents a complex phenomenon that strongly depends on several factors such as pressure, temperature, fuel chemical composition, and the extent of premixing. The effect of partial premixing on soot formation is of relevance also for real combustion devices and still needs to be fully understood. An improved version of the thermophoretic particle densitometry (TPD method has been used in this work with the aim to obtain both quantitative and qualitative information of soot particles generated in a set of laminar partially-premixed coflow flames characterized by different equivalence ratios. To this aim, the transient thermocouple temperature response has been analyzed to infer particle concentration and emissivity. A variety of thermal emissivity values have been measured for flame-formed carbonaceous particles, ranging from 0.4 to 0.5 for the early nucleated soot particles up to the value of 0.95, representing the typical value commonly attributed to mature soot particles, indicating that the correct determination of the thermal emissivity is necessary to accurately evaluate the particle volume fraction. This is particularly true at the early stage of the soot formation, when particle concentration measurement is indeed particularly challenging as in the central region of the diffusion flames. With increasing premixing, an initial increase of particles is detected both in the maximum radial soot volume fraction region and in the central region of the flame, while the further addition of primary air determines the particle volume fraction drop. Finally, a modeling analysis based on a sectional approach has been performed to corroborate the experimental findings.

  16. Indoor emissions as a primary source of airborne allergenic fungal particles in classrooms.

    Science.gov (United States)

    Yamamoto, Naomichi; Hospodsky, Denina; Dannemiller, Karen C; Nazaroff, William W; Peccia, Jordan

    2015-04-21

    This study quantifies the influence of ventilation and indoor emissions on concentrations and particle sizes of airborne indoor allergenic fungal taxa and further examines geographical variability, each of which may affect personal exposures to allergenic fungi. Quantitative PCR and multiplexed DNA sequencing were employed to count and identify allergenic fungal aerosol particles indoors and outdoors in seven school classrooms in four different countries. Quantitative diversity analysis was combined with building characterization and mass balance modeling to apportion source contributions of indoor allergenic airborne fungal particles. Mass balance calculations indicate that 70% of indoor fungal aerosol particles and 80% of airborne allergenic fungal taxa were associated with indoor emissions; on average, 81% of allergenic fungi from indoor sources originated from occupant-generated emissions. Principal coordinate analysis revealed geographical variations in fungal communities among sites in China, Europe, and North America (p < 0.05, analysis of similarity), demonstrating that geography may also affect personal exposures to allergenic fungi. Indoor emissions including those released with occupancy contribute more substantially to allergenic fungal exposures in classrooms sampled than do outdoor contributions from ventilation. The results suggest that design and maintenance of buildings to control indoor emissions may enable reduced indoor inhalation exposures to fungal allergens.

  17. Comprehensive decay law for emission of charged particles and exotic cluster radioactivity

    Indian Academy of Sciences (India)

    Basudeb Sahu

    2014-04-01

    A general decay formula for the emission of charged particles from metastable nuclei is developed based on the basic phenomenon of resonances occurring in quantum scattering process under Coulomb-nuclear potential. It relates the half-lives of radioactive decays with the values of the outgoing elements with masses and charges of the nuclei involved in the decay. The relation is found to be a generalization of the Geiger–Nuttall law in radioactivity and explains well all the known emissions of charged particles including clusters, alpha and proton.

  18. Real-World Emission of Particles from Vehicles: Volatility and the Effects of Ambient Temperature.

    Science.gov (United States)

    Wang, Jonathan M; Jeong, Cheol-Heon; Zimmerman, Naomi; Healy, Robert M; Hilker, Nathan; Evans, Greg J

    2017-03-16

    A majority of the ultrafine particles observed in real-world conditions are systematically excluded from many measurements that help to guide regulation of vehicle emissions. To investigate the impact of this exclusion, coincident near-road particle number (PN) emission factors were quantified up- and downstream of a thermodenuder during two seasonal month-long campaigns with wide-ranging ambient temperatures (-19 to +30 °C) to determine the volatile fraction of particles. During colder temperatures (20 °C). Additionally, mean PN emission factors were a factor of 3.8 higher during cold compared to warm periods. On the basis of 130 000 vehicle plumes including three additional campaigns, fleet mean emission factors were calculated for PN (8.5 × 10(14) kg-fuel(-1)), black carbon (37 mg kg-fuel(-1)), organic aerosol (51 mg kg-fuel(-1)), and particle-bound polycyclic aromatic hydrocarbons (0.7 mg kg-fuel(-1)). These findings demonstrate that significant differences exist between particles in thermally treated vehicle exhaust as compared to in real-world vehicle plumes to which populations in near-road environments are actually exposed. Furthermore, the magnitude of these differences are dependent upon season and may be more extreme in colder climates.

  19. Fine particle emissions, emission reduction potential and reduction costs in Finland in 2020

    OpenAIRE

    Karvosenoja, Niko; Klimont, Zbigniew; Tohka, Antti; Johansson, Matti

    2006-01-01

    Fine particulate matter (PM2.5) in the atmosphere have been associated with severe human health effects. This report explores future emissions of primary PM2.5, their reduction potential and related reduction costs in Finland. One activity pathway of 2020 of the Finnish Climate Strategy was studied with two different PM emission control utilization scenarios: (1) "Baseline" which involves PM control technology utilization complying with current legislation, and (2) "Reduction" which assumes t...

  20. More Detailed Study of Deformation Effects in Prescission Particle Emission by a Diffusion Model

    Institute of Scientific and Technical Information of China (English)

    YE Wei

    2003-01-01

    Deformation effects on particle emission in a fission process of 251Es nucleus as functions of excitationenergy, angular momentum, and viscosity coefficient have been investigated in detail within the framework of Smolu-chowski equation. Our calculations show that high excitation energy, low angular momentum, and large viscosity willenhance the influence of deformation on multiplicity of prescission particles, and that the roles of these three parameterswill become weak with decreasing deformation.

  1. More Detailed Study of Deformation Effects in Prescission Particle Emission by a Diffusion Model

    Institute of Scientific and Technical Information of China (English)

    YEWei

    2003-01-01

    Deformation effects on particle emission in a fission process of 251Es nucleus as functions of excitation energy, angular momentum, and viscosity coefficient have been investigated in detail within the framework of Smolu-chowski equation. Our calculations show that high excitation energy, low angular momentum, and large viscosity will enhance the influence of deformation on multiplicity of prescission particles, and that the roles of these three parameters will become weak with decreasing deformation.

  2. Development of a Reference Database for Particle-Induced Gamma-ray Emission spectroscopy

    OpenAIRE

    Dimitriou, P.; Becker, H.-W.; Bogdanović-Radović, I.; M. Chiari; Goncharov, A.; Jesus, A. P.; Kakuee, O.; Kiss, A. Z.; Lagoyannis, A.; Räisänen, J.; Strivay, David; Zucchiatti, A.

    2016-01-01

    Particle-Induced Gamma-ray Emission (PIGE) is a powerful analytical technique that exploits the interactions of rapid charged particles with nuclei located near a sample surface to determine the composition and structure of the surface regions of solids by measurement of characteristic prompt γ rays. The potential for depth profiling of this technique has long been recognized, however, the implementation has been limited owing to insufficient knowledge of the physical data and lack of suitabl...

  3. Physical meaning of two-particle HBT measurements in case of correlated emission

    OpenAIRE

    Bialas, A.; Zalewski, K.

    2004-01-01

    It is shown that, in the presence of correlations in particle emission, the measured HBT radii are related to the correlation range rather than to the size of the interaction volume. Only in the case of weak correlations the standard interpretation may be applicable, The earlier discussion [1] of short-range correlations in configuration space is generalized to include also the correlations of particle momenta.

  4. African Anthropogenic Emissions Inventories for gases and particles from 1990 to 2016

    Science.gov (United States)

    Liousse, Catherine; Keita, Sekou; N'Datchoch Touré, Evelyne 1; Doumbia, Thierno; Yoboué, Véronique; Assamoi, Eric; Haslett, Sophie; Roblou, Laurent; Léon, Jean-François; Galy-Lacaux, Corinne; Akpo, Aristide; Coe, Hugh

    2017-04-01

    Presently, there is one African regional inventory dealing with biofuel and fossil fuel emissions (Liousse et al., 2014) and only global emission inventories including Africa. Developing a regional inventory for gases and particles is not an easy task: the DACCIWA project has allowed to organize a framework suitable for this development through regrouping several investigators. The aim is to set an African database on fuel consumption and new emission factor measurements and to include other sources of pollution than biofuel and fossil fuel such as flaring and waste burning yet not negligible in Africa. The inclusion of these sources in the new inventory and also new emissions factor measurements will reduce the uncertainties on anthropogenic emissions in Africa. This work will present the first version of African fossil fuel (FF), biofuel (BF), gas flaring and waste burning emission inventories for the 1990-2016 period for the major atmospheric compounds (gases and particles) provides up to date emission fields at 0.125° x 0.125° spatial resolution and yearly temporal resolution that can be used to model atmospheric composition and impacts over West Africa. New emission factor measurements on ground and in combustion chambers will be discussed. Temporal variability of emissions from 1990 to 2016 will be scrutinized. In parallel, uncertainties on existing biomass burning emission inventories will be presented. New emission inventories based on MODIS burnt area products and AMMABB methodology have been developed for the period 2000-2012. They will be compared with GFED and GFAS products. Finally, tests on these inventories in Regional Climate Model (RegCM) at African scale will be presented for different years.

  5. Searches for invisible Higgs boson decays with the CMS detector.

    CERN Document Server

    CMS Collaboration

    2016-01-01

    Searches for invisible decays of the Higgs boson are presented. The data collected with the CMS detector at the LHC correspond to integrated luminosities of $5.1$, $19.7$, and $2.3~\\mathrm{fb}^{-1}$ at centre-of-mass energies of 7, 8, and $13~\\mathrm{TeV}$, respectively. The search channels target Higgs boson production via gluon fusion, vector boson fusion, and in association with a vector boson. Upper limits are placed on the branching fraction of the Higgs boson decay to invisible particles, as a function of the assumed production cross sections. The combination of all channels, assuming standard model production cross sections, yields an observed (expected) upper limit on the invisible branching fraction of $0.24$ ($0.23$) at a $95\\%$ confidence level. The results are also interpreted under Higgs-portal dark matter models.

  6. Climate effects of a hypothetical regional nuclear war: Sensitivity to emission duration and particle composition

    Science.gov (United States)

    Pausata, Francesco S. R.; Lindvall, Jenny; Ekman, Annica M. L.; Svensson, Gunilla

    2016-11-01

    Here, we use a coupled atmospheric-ocean-aerosol model to investigate the plume development and climate effects of the smoke generated by fires following a regional nuclear war between emerging third-world nuclear powers. We simulate a standard scenario where 5 Tg of black carbon (BC) is emitted over 1 day in the upper troposphere-lower stratosphere. However, it is likely that the emissions from the fires ignited by bomb detonations include a substantial amount of particulate organic matter (POM) and that they last more than 1 day. We therefore test the sensitivity of the aerosol plume and climate system to the BC/POM ratio (1:3, 1:9) and to the emission length (1 day, 1 week, 1 month). We find that in general, an emission length of 1 month substantially reduces the cooling compared to the 1-day case, whereas taking into account POM emissions notably increases the cooling and the reduction of precipitation associated with the nuclear war during the first year following the detonation. Accounting for POM emissions increases the particle size in the short-emission-length scenarios (1 day/1 week), reducing the residence time of the injected particle. While the initial cooling is more intense when including POM emission, the long-lasting effects, while still large, may be less extreme compared to the BC-only case. Our study highlights that the emission altitude reached by the plume is sensitive to both the particle type emitted by the fires and the emission duration. Consequently, the climate effects of a nuclear war are strongly dependent on these parameters.

  7. A novel field measurement method for determining fine particle and gas emissions from residential wood combustion

    Science.gov (United States)

    Tissari, Jarkko; Hytönen, Kati; Lyyränen, Jussi; Jokiniemi, Jorma

    Emission data from residential wood combustion are usually obtained on test stands in the laboratory but these measurements do not correspond to the operational conditions in the field because of the technological boundary conditions (e.g. testing protocol, environmental and draught conditions). The field measurements take into account the habitual practice of the operators and provide the more reliable results needed for emission inventories. In this study, a workable and compact method for measuring emissions from residential wood combustion in winter conditions was developed. The emissions for fine particle, gaseous and PAH compounds as well as particle composition in real operational conditions were measured from seven different appliances. The measurement technique worked well and was evidently suitable for winter conditions. It was easy and fast to use, and no construction scaffold was needed. The dilution of the sample with the combination of a porous tube diluter and an ejector diluter was well suited to field measurement. The results indicate that the emissions of total volatile organic carbon (TVOC) (17 g kg -1 (of dry wood burned)), carbon monoxide (CO) (120 g kg -1) and fine particle mass (PM 1) (2.7 g kg -1) from the sauna stove were higher than in the other measured appliances. In the masonry heaters, baking oven and stove, the emissions were 2.9-9 g kg -1 TVOC, 28-68 g kg -1 CO and 0.6-1.6 g kg -1 PM 1. The emission of 12 PAHs (PAH 12) from the sauna stove was 164 mg kg -1 and consisted mainly of PAHs with four benzene rings in their structure. PAH 12 emission from other appliances was, on average, 21 mg kg -1 and was dominated by 2-ring PAHs. These results indicate that despite the non-optimal operational practices in the field, the emissions did not differ markedly from the laboratory measurements.

  8. On the potential contribution of open lead particle emissions to the central Arctic aerosol concentration

    Directory of Open Access Journals (Sweden)

    A. Held

    2010-10-01

    Full Text Available During the ice-breaker borne ASCOS expedition (Arctic Summer Cloud Ocean Study direct eddy covariance measurements of aerosol number fluxes were carried out in August 2008 on the edge of an ice floe drifting in the central Arctic Ocean between 2°–10° W longitude and 87°–87.5° N latitude. The median aerosol transfer velocities over different surface types (open water leads, ice ridges, snow and ice surfaces ranged from 0.27 to 0.68 mm s−1 during deposition-dominated episodes. Emission periods were observed more frequently over the open lead, while the snow behaved primarily as a deposition surface. Directly measured aerosol fluxes were compared with particle deposition parameterizations in order to estimate the emission flux from the observed net aerosol flux. Finally, the contribution of the open lead particle source to atmospheric variations in particle number concentration was evaluated and compared with the observed temporal evolution of particle number. The direct emission of aerosol particles from the open lead can only explain 5–10% of the observed particle number variation in the mixing layer close to the surface.

  9. Particle Acceleration, Magnetic Field Generation and Emission from Relativistic Jets and Supernova Remnants

    Science.gov (United States)

    Nishikawa, K.-I.; Hartmann, D. H.; Hardee, P.; Hededal, C.; Mizunno, Y.; Fishman, G. J.

    2006-01-01

    We performed numerical simulations of particle acceleration, magnetic field generation, and emission from shocks in order to understand the observed emission from relativistic jets and supernova remnants. The investigation involves the study of collisionless shocks, where the Weibel instability is responsible for particle acceleration as well as magnetic field generation. A 3-D relativistic particle-in-cell (RPIC) code has been used to investigate the shock processes in electron-positron plasmas. The evolution of theWeibe1 instability and its associated magnetic field generation and particle acceleration are studied with two different jet velocities (0 = 2,5 - slow, fast) corresponding to either outflows in supernova remnants or relativistic jets, such as those found in AGNs and microquasars. Slow jets have intrinsically different structures in both the generated magnetic fields and the accelerated particle spectrum. In particular, the jet head has a very weak magnetic field and the ambient electrons are strongly accelerated and dragged by the jet particles. The simulation results exhibit jitter radiation from inhomogeneous magnetic fields, generated by the Weibel instability, which has different spectral properties than standard synchrotron emission in a homogeneous magnetic field.

  10. INVISIBLE MURDERER: NEONATAL TETANUS

    Directory of Open Access Journals (Sweden)

    Yonca SONMEZ

    2006-06-01

    Full Text Available Neonatal tetanus (NNT has been secondary in the whole world in the death list of diseases which can be protected by the help of vaccine. It’s an important community health problem in the less-developed countries in which pre-birth care services are limited, assisting a mother at childbirth by uneducated people in dirty atmosphere and the immunity against tetanus is not enough. Studies have shown that minor part of the cases have been expressed in most of the countries. Because of that NNT have been called as “silent/invisible murderer”. In Turkey, in the year of 2003 it has been seen 15 cases, and 12 of them have been resulted in death. The methods which will be applied to carry out the elimination of NNT are; the vaccination of pregnant women with at least two doses tetanus toxoid and providing clean birth conditions for all of the pregnant women. However, in Turkey the proportion of the women who have two doses of tetanus vaccine is 41%. To eliminate NNT in our country, all the pregnant women must be attained, the ones who are attained must be presented with qualified pre-birth care service which also includes tetanus immunity and the births must be carried out under healty conditions. As smallpox and polio eradication, NNT elimination will also be accomplished by self-sacrificing works of personnel in primary health care. [TAF Prev Med Bull 2006; 5(3.000: 229-233

  11. Practical Invisibility Cloaking

    Science.gov (United States)

    Choi, Joseph Sung-hwoon

    This thesis presents mainly two methodologies for achieving practical invisibility cloaking. Thus, using commercial technologies, devices that are good approximations to an 'ideal' cloak can be achieved - a cloak that is omnidirectional, broadband, operational for the visible spectrum, three-dimensional (3D), and phase-matching for the light field, among other attributes. We first describe 'paraxial cloaking,' where cloaking is considered as an imaging system. The small-angle ('paraxial') formalism provides a first-order design requirement for any 'perfect' cloaking device. A ray optics four-lens cloak (called the "Rochester Cloak'") is experimentally demonstrated, followed by theoretical work to match the phase for the entire visible spectrum. To extend our broadband, paraxial cloak to larger viewing angles, we then discretize space, angle, spectrum, and phase to approximate an ideal, omnidirectional cloak. Such 'discretized cloaking' is experimentally demonstrated as a 'digital cloak,' where commercially available digital image capture and display technologies are used. In particular, we demonstrate an active cloak that uses lenticular lenslet arrays, similar to 'integral imaging' for 3D displays. The 'digital integral cloak' we demonstrate is dynamic, but requires a time delay for image capture and processing, and is two-dimensional (2D) without phase-matching. Continuing improvements in commercial digital technology and computational power will minimize the resolution limitations of a digital cloak and enhance its processing speed. Thus, a wearable cloak can then be practically realized in the future.

  12. The Invisible Web

    CERN Multimedia

    Katarina Anthony

    2010-01-01

    There is an invisible web beneath CERN that keeps the entire system going. It often goes unnoticed, yet is responsible for transmitting the vast amounts of data produced at CERN: the optical fibre network.   CERN’s 35,000 km of optical fibres are also used to synchronise the accelerators, take measurements of the beams and to send controls to the LHC. The network is maintained by a team of seven specialists working in the Cabling and Optical Fibres Section of the Engineering Department, while another eight specialists are responsible for copper control and direct current (DC) power cabling (412,000 cables at CERN). Although their work is essential to keep the LHC running, their record-breaking developments often go unspoken. In a recent seminar held on 14 October, the Optical Fibre team had the opportunity to present their exceptional work with radiation-resistant optical fibres. Daniel Ricci at the CCC optical fibre “starpoint”, which serves the LHC installation...

  13. Airborne studies of emissions from savanna fires in southern Africa. 1. Aerosol emissions measured with a laser optical particle counter

    Science.gov (United States)

    Le Canut, P.; Andreae, M. O.; Harris, G. W.; Wienhold, F. G.; Zenker, T.

    1996-10-01

    During the SAFARI-92 experiment (Southern Africa Fire Atmosphere Research Initiative, September-October 1992), we flew an instrumented DC-3 aircraft through plumes from fires in various southern African savanna ecosystems. Some fires had been managed purposely for scientific study (e.g., those in Kruger National Park, South Africa), while the others were "fires of opportunity" which are abundant during the burning season in southern Africa. We obtained the aerosol (0.1-3.0 μm diameter) number and mass emission ratios relative to carbon monoxide and carbon dioxide from 21 individual fires. The average particle number emission ratio ΔN/ΔCO (Δ: concentrations in plume minus background concentrations) varied between 14 ± 2 cm-3 ppb-1 for grasslands and 23 ± 7 cm-3 ppb-1 for savannas. An exceptionally high value of 43 ± 4 cm-3 ppb-1 was measured for a sugarcane fire. Similarly, the mass emission ratio ΔM/ΔCO varied from 36 ± 6 ng m-3 ppb-1 to 83 ± 45 ng m-3 ppb-1, respectively, with again an exceptionally high value of 124 ± 14 ng m-3 ppb-1 for the sugarcane fire. The number and mass emission ratios relative to CO depended strongly upon the fire intensity. Whereas the emission ratios varied greatly from one fire to the other, the aerosol number and volume distributions as a function of particle size were very consistent. The average background aerosol size distribution was characterized by three mass modes (0.2-0.4 μm, ≈1.0 μm, and ≈2.0 μm diameter). On the other hand, the aerosol size distribution in the smoke plumes showed only two mass modes, one centered in the interval 0.2-0.3 μm and the other above 2 μm diameter. From our mean emission factor (4 ± 1 g kg-1 dm) we estimate that savanna fires release some 11-18 Tg aerosol particles in the size range 0.1-3.0 μm annually, a somewhat lower amount than emitted from tropical forest fires. Worldwide, savanna fires emit some 3-8 × 1027 particles (in the same size range) annually, which is expected

  14. Ultrafine particle size as a tracer for aircraft turbine emissions.

    Science.gov (United States)

    Riley, Erin A; Gould, Timothy; Hartin, Kris; Fruin, Scott A; Simpson, Christopher D; Yost, Michael G; Larson, Timothy

    2016-08-01

    Ultrafine particle number (UFPN) and size distributions, black carbon, and nitrogen dioxide concentrations were measured downwind of two of the busiest airports in the world, Los Angeles International Airport (LAX) and Hartsfield-Jackson International Airport (ATL - Atlanta, GA) using a mobile monitoring platform. Transects were located between 5 km and 10 km from the ATL and LAX airports. In addition, measurements were taken at 43 additional urban neighborhood locations in each city and on freeways. We found a 3-5 fold increase in UFPN concentrations in transects under the landing approach path to both airports relative to surrounding urban areas with similar ground traffic characteristics. The latter UFPN concentrations measured were distinct in size distributional properties from both freeways and across urban neighborhoods, clearly indicating different sources. Elevated concentrations of Black Carbon (BC) and NO2 were also observed on airport transects, and the corresponding pattern of elevated BC was consistent with the observed excess UFPN concentrations relative to other urban locations.

  15. Particle number emissions of motor traffic derived from street canyon measurements in a Central European city

    Science.gov (United States)

    Klose, S.; Birmili, W.; Voigtländer, J.; Tuch, T.; Wehner, B.; Wiedensohler, A.; Ketzel, M.

    2009-02-01

    A biennial dataset of ambient particle number size distributions (diameter range 4-800 nm) collected in urban air in Leipzig, Germany, was analysed with respect to the influence of traffic emissions. Size distributions were sampled continuously in 2005 and 2006 inside a street canyon trafficked by ca. 10 000 motor vehicles per day, and at a background reference site distant at 1.5 km. Auto-correlation analysis showed that the impact of fresh traffic emissions could be seen most intensely below particle sizes of 60 nm. The traffic-induced concentration increment at roadside was estimated by subtracting the urban background values from the street canyon measurement. To describe the variable dispersion conditions inside the street canyon, micro-meteorological dilution factors were calculated using the Operational Street Pollution Model (OSPM), driven by above-roof wind speed and wind direction observations. The roadside increment concentrations, dilution factor, and real-time traffic counts were used to calculate vehicle emission factors (aerosol source rates) that are representative of the prevailing driving conditions, i.e. stop-and-go traffic including episodes of fluent traffic flow at speeds up to 40 km h-1. The size spectrum of traffic-derived particles was essentially bimodal - with mode diameters around 12 and 100 nm, while statistical analysis suggested that the emitted number concentration varied with time of day, wind direction, particle size and fleet properties. Significantly, the particle number emissions depended on ambient temperature, ranging between 4.8 (±1.8) and 7.8 (±2.9).1014 p. veh-1 km-1 in summer and winter, respectively. A separation of vehicle types according to vehicle length suggested that lorry-like vehicles emit about 80 times more particle number than passenger car-like vehicles. Using nitrogen oxide (NOx) measurements, specific total particle number emissions of 338 p. (pg NOx)-1 were inferred. The calculated traffic emission factors

  16. Particle emission rates during electrostatic spray deposition of TiO2 nanoparticle-based photoactive coating

    DEFF Research Database (Denmark)

    Koivisto, Antti J.; Jensen, Alexander C. Ø.; Kling, Kirsten I.

    2017-01-01

    to 31μm-size particles and volatile organic compounds (VOC), as well as particle deposition onto room surfaces and on the spray gun user hand. The particle emission and deposition rates were quantified using aerosol mass balance modelling. The geometric mean particle number emission rate was 1.9×1010s-1...... and the mean mass emission rate was 381μgs-1. The respirable mass emission-rate was 65% lower than observed for the entire measured size-range. The mass emission rates were linearly scalable (±ca. 20%) to the process duration. The particle deposition rates were up to 15h-1 for......Here, we studied the particle release rate during Electrostatic spray deposition of anatase-(TiO2)-based photoactive coating onto tiles and wallpaper using a commercially available electrostatic spray device. Spraying was performed in a 20.3m3 test chamber while measuring concentrations of 5.6nm...

  17. Effects of Alternative Fuels and Aromatics on Gas-Turbine Particle Emissions

    Science.gov (United States)

    Thornhill, K. L., II; Moore, R.; Winstead, E.; Anderson, B. E.; Klettlinger, J. L.; Ross, R. C.; Surgenor, A.

    2015-12-01

    This presentation describes experiments conducted with a Honeywell GTCP36-150 Auxiliary Power Unit (APU) to evaluate the effects of varying fuel composition on particle emissions. The APU uses a single-stage compressor stage, gas turbine engine with a can-type combustor to generate bypass flow and electrical power for supporting small aircraft and helicopters. It is installed in a "hush-house" at NASA Glenn Research Center and is configured as a stand-alone unit that can be fueled from an onboard tank or external supply. It operates at constant RPM, but its fuel flow can be varied by changing the electrical load or volume of bypass flow. For these tests, an external bank of resistors were attached to the APU's DC and AC electrical outlets and emissions measurements were made at low, medium and maximum electrical current loads. Exhaust samples were drawn from several points downstream in the exhaust duct and fed to an extensive suite of gas and aerosol sensors installed within a mobile laboratory parked nearby. Aromatic- and sulfur-free synthetic kerosenes from Rentech, Gevo, UOP, Amyris and Sasol were tested and their potential to reduce PM emissions evaluated against a single Jet A1 base fuel. The role of aromatic compounds in regulating soot emissions was also evaluated by adding metered amounts of aromatic blends (Aro-100, AF-Blend, SAK) and pure compounds (tetracontane and 1-methylnaphthalene) to a base alternative fuel (Sasol). Results show that, relative to Jet A1, alternative fuels reduce nonvolatile particle number emissions by 50-80% and--by virtue of producing much smaller particles—mass emissions by 65-90%; fuels with the highest hydrogen content produced the greatest reductions. Nonvolatile particle emissions varied in proportion to fuel aromatic content, with additives containing the most complex ring structures producing the greatest emission enhancements.

  18. TOTAL PARTICLE, SULFATE, AND ACIDIC AEROSOL EMISSIONS FROM KEROSENE SPACE HEATERS

    Science.gov (United States)

    Chamber studies were conducted on four unvented kerosene space heaters to assess emissions of total particle, sulfate, and acidic aerosol. The heaters tested represented four burner designs currently in use by the public. Kerosene space heaters are a potential source of fine part...

  19. Modelling molecular iodine emissions in a coastal marine environment: the link to new particle formation

    Science.gov (United States)

    Saiz-Lopez, A.; Plane, J. M. C.; McFiggans, G.; Williams, P. I.; Ball, S. M.; Bitter, M.; Jones, R. L.; Hongwei, C.; Hoffmann, T.

    2006-03-01

    A model of iodine chemistry in the marine boundary layer (MBL) has been used to investigate the impact of daytime coastal emissions of molecular iodine (I2). The model contains a full treatment of gas-phase iodine chemistry, combined with a description of the nucleation and growth, by condensation and coagulation, of iodine oxide nano-particles. In-situ measurements of coastal emissions of I2 made by the broadband cavity ring-down spectroscopy (BBCRDS) and inductively coupled plasma-mass spectrometry (ICP/MS) techniques are presented and compared to long path differential optical absorption spectroscopy (DOAS) observations of I2 at Mace Head, Ireland. Simultaneous measurements of enhanced I2 emissions and particle bursts show that I2 is almost certainly the main precursor of new particles at this coastal location. The ratio of IO to I2 predicted by the model indicates that the iodine species observed by the DOAS are concentrated over a short distance (about 8% of the 4.2 km light path) consistent with the intertidal zone, bringing them into good agreement with the I2 measurements made by the two in-situ techniques. The model is then used to investigate the effect of iodine emission on ozone depletion, and the production of new particles and their evolution to form stable cloud condensation nuclei (CCN).

  20. Modelling molecular iodine emissions in a coastal marine environment: the link to new particle formation

    Directory of Open Access Journals (Sweden)

    A. Saiz-Lopez

    2006-01-01

    Full Text Available A model of iodine chemistry in the marine boundary layer (MBL has been used to investigate the impact of daytime coastal emissions of molecular iodine (I2. The model contains a full treatment of gas-phase iodine chemistry, combined with a description of the nucleation and growth, by condensation and coagulation, of iodine oxide nano-particles. In-situ measurements of coastal emissions of I2 made by the broadband cavity ring-down spectroscopy (BBCRDS and inductively coupled plasma-mass spectrometry (ICP/MS techniques are presented and compared to long path differential optical absorption spectroscopy (DOAS observations of I2 at Mace Head, Ireland. Simultaneous measurements of enhanced I2 emissions and particle bursts show that I2 is almost certainly the main precursor of new particles at this coastal location. The ratio of IO to I2 predicted by the model indicates that the iodine species observed by the DOAS are concentrated over a short distance (about 8% of the 4.2 km light path consistent with the intertidal zone, bringing them into good agreement with the I2 measurements made by the two in-situ techniques. The model is then used to investigate the effect of iodine emission on ozone depletion, and the production of new particles and their evolution to form stable cloud condensation nuclei (CCN.

  1. Emission and Size Distribution of Particle-bound Polycyclic Aromatic Hydrocarbons from Residential Wood Combustion

    Science.gov (United States)

    Shen, Guofeng; Wei, Siye; Zhang, Yanyan; Wang, Bin; Wang, Rong; Shen, Huizhong; Li, Wei; Huang, Ye; Chen, Yuanchen; Chen, Han; Tao, Shu

    2015-01-01

    Emissions and size distributions of 28 particle-bound polycyclic aromatic hydrocarbons (PAHs) from residential combustion of 19 fuels in a domestic cooking stove in rural China were studied. Measured emission factors of total PAHs were 1.79±1.55, 12.1±9.1, and 5.36±4.46 mg/kg for fuel wood, brushwood, and bamboo, respectively. Approximate 86.7, 65.0, and 79.7% of the PAHs were associated with fine particulate matter with size less than 2.1 µm for these three types of fuels. Statistically significant difference in emission factors and size distributions of particle-bound PAHs between fuel wood and brushwood was observed, with the former had lower emission factors but more PAHs in finer PM. Mass fraction of the fine particles associated PAHs was found to be positively correlated with fuel density and moisture, and negatively correlated with combustion efficiency. Low and high molecular weight PAHs segregated into the coarse and fine PM, respectively. The high accumulation tendency of the PAHs from residential wood combustion in fine particles implies strong adverse health impact. PMID:25678760

  2. Mote cyclone robber system particulate emission factors for cotton gins: Particle size distribution characteristics

    Science.gov (United States)

    This report is part of a project to characterize cotton gin emissions from the standpoint of total particulate stack sampling and particle size analyses. In 2013, the U.S. Environmental Protection Agency (EPA) published a more stringent standard for particulate matter with nominal diameter less than...

  3. Cyclone robber system particulate emission factors for cotton gins: Particle size distribution characteristics

    Science.gov (United States)

    This report is part of a project to characterize cotton gin emissions from the standpoint of total particulate stack sampling and particle size analyses. In 2013, U.S. Environmental Protection Agency (EPA) published a more stringent standard for particulate matter with nominal diameter less than or ...

  4. Battery condenser system particulate emission factors for cotton gins: Particle size distribution characteristics

    Science.gov (United States)

    This report is part of a project to characterize cotton gin emissions from the standpoint of total particulate stack sampling and particle size analyses. In 2013, the Environmental Protection Agency (EPA) published a more stringent standard for particulate matter with nominal diameter less than or e...

  5. Size Differentiation Of A Continuous Stream Of Particles Using Acoustic Emissions

    Science.gov (United States)

    Nsugbe, E.; Starr, A.; Foote, P.; Ruiz-Carcel, C.; Jennions, I.

    2016-11-01

    Procter and Gamble (P&G) require an online system that can monitor the particle size distribution of their washing powder mixing process. This would enable the process to take a closed loop form which would enable process optimisation to take place in real time. Acoustic Emission (AE) was selected as the sensing method due to its non-invasive nature and primary sensitivity to frequencies which particle events emanate. This work details the results of the first experiment carried out in this research project. This experiment involved the use of AE to distinguish between the sizes of sieved polyethylene particle (53-250microns) and glass beads (150-600microns) which were dispensed on a target plate using a funnel. By conducting a threshold analysis of the impact peaks in the signal, the sizes of the particles could be distinguished and a signal feature was found which could be directly linked to the sizes of the particles.

  6. Regional impacts of ultrafine particle emissions from the surface of the Great Lakes

    Directory of Open Access Journals (Sweden)

    S. H. Chung

    2011-05-01

    Full Text Available Quantifying the impacts of aerosols on climate requires a detailed knowledge of both the anthropogenic and the natural contributions to the aerosol population. Recent work has suggested a previously unrecognized natural source of ultrafine particles resulting from breaking waves at the surface of large freshwater lakes. This work is the first modeling study to investigate the potential for this newly discovered source to affect the aerosol number concentrations on regional scales. Using the WRF-Chem modeling framework, the impacts of wind-driven aerosol production from the surface of the Great Lakes were studied for a July 2004 test case. Simulations were performed for a base case with no lake surface emissions, a case with lake surface emissions included, and a default case wherein large freshwater lakes emit marine particles as if they were oceans. Results indicate that the lake surface emissions can enhance the surface level aerosol number concentration by ∼20 % over the remote northern Great Lakes and by ∼5 % over other parts of the Great Lakes. These results were highly sensitive the nucleation parameterization within WRF-Chem; when the nucleation process was deactivated, surface-layer enhancements from the lake emissions increased to as much as 200 %. The results reported here have significant uncertainties associated with the lake emission parameterization and the way ultrafine particles are modeled within WRF-Chem. Nevertheless, the magnitude of the impacts found in this study suggest that further study of this phenomena is merited.

  7. Morphology and Optical Properties of Black-Carbon Particles Relevant to Engine Emissions

    Science.gov (United States)

    Michelsen, H. A.; Bambha, R.; Dansson, M. A.; Schrader, P. E.

    2013-12-01

    Black-carbon particles are believed to have a large influence on climate through direct radiative forcing, reduction of surface albedo of snow and ice in the cryosphere, and interaction with clouds. The optical properties and morphology of atmospheric particles containing black carbon are uncertain, and characterization of black carbon resulting from engines emissions is needed. Refractory black-carbon particles found in the atmosphere are often coated with unburned fuel, sulfuric acid, water, ash, and other combustion by-products and atmospheric constituents. Coatings can alter the optical and physical properties of the particles and therefore change their optical properties and cloud interactions. Details of particle morphology and coating state can also have important effects on the interpretation of optical diagnostics. A more complete understanding of how coatings affect extinction, absorption, and incandescence measurements is needed before these techniques can be applied reliably to a wide range of particles. We have investigated the effects of coatings on the optical and physical properties of combustion-generated black-carbon particles using a range of standard particle diagnostics, extinction, and time-resolved laser-induced incandescence (LII) measurements. Particles were generated in a co-flow diffusion flame, extracted, cooled, and coated with oleic acid. The diffusion flame produces highly dendritic soot aggregates with similar properties to those produced in diesel engines, diffusion flames, and most natural combustion processes. A thermodenuder was used to remove the coating. A scanning mobility particle sizer (SMPS) was used to monitor aggregate sizes; a centrifugal particle mass analyzer (CPMA) was used to measure coating mass fractions, and transmission electron microscopy (TEM) was used to characterize particle morphologies. The results demonstrate important differences in optical measurements between coated and uncoated particles.

  8. Size-Resolved Source Emission Rates of Indoor Ultrafine Particles Considering Coagulation.

    Science.gov (United States)

    Rim, Donghyun; Choi, Jung-Il; Wallace, Lance A

    2016-09-20

    Indoor ultrafine particles (UFP, log-normally distributed for three common indoor UFP sources: an electric stove, a natural gas burner, and a paraffin wax candle. Experimental investigations were performed in a full-scale test building. Size- and time-resolved concentrations of UFP ranging from 2 to 100 nm were monitored using a scanning mobility particle sizer (SMPS). Based on the temporal evolution of the particle size distribution during the source emission period, the size-dependent source emission rate was determined using a material-balance modeling approach. The results indicate that, for a given UFP source, the source strength varies with particle size and source type. The analytical model assuming a log-normally distributed source emission rate could predict the temporal evolution of the particle size distribution with reasonable accuracy for the gas stove and the candle. Including the effect of coagulation was found to increase the estimates of source strengths by up to a factor of 8. This result implies that previous studies on indoor UFP source strengths considering only deposition and ventilation might have largely underestimated the true values of UFP source strengths, especially for combustion due to the natural gas stove and the candle.

  9. Alpha-particle emission probabilities in the decay of {sup 240}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Sibbens, G., E-mail: goedele.sibbens@ec.europa.e [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel (Belgium); Pomme, S.; Altzitzoglou, T. [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel (Belgium); Garcia-Torano, E. [Laboratorio de Metrologia de Radiaciones Ionizantes, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Janssen, H.; Dersch, R.; Ott, O. [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Martin Sanchez, A. [Departamento de Fisica, Universidad de Extremadura, Badajoz, E-06071 (Spain); Rubio Montero, M.P. [Departamento de Fisica Aplicada, Universidad de Extremadura, Merida, Badajoz, E-06800 (Spain); Loidl, M. [Laboratoire National Henri Becquerel, LNE/CEA-LIST, 91191 Gif-sur-Yvette (France); Coron, N.; Marcillac, P. de [Institut d' Astrophysique Spatiale, CNRS, 91405 Orsay Campus (France); Semkow, T.M. [Wadsworth Center, New York State Department of Health, Albany, NY 12201 (United States)

    2010-07-15

    Sources of enriched {sup 240}Pu were prepared by vacuum evaporation on quartz substrates. High-resolution alpha-particle spectrometry of {sup 240}Pu was performed with high statistical accuracy using silicon detectors and with low statistical accuracy using a bolometer. The alpha-particle emission probabilities of six transitions were derived from the spectra and compared with literature values. Additionally, some alpha-particle emission probabilities were derived from {gamma}-ray intensity measurements with a high-purity germanium detector. The alpha-particle emission probabilities of the three main transitions at 5168.1, 5123.6 and 5021.2 keV were derived from seven aggregate spectra analysed with five different fit functions and the results were compatible with evaluated data. Two additional weak peaks at 4863.5 and 4492.0 keV were fitted separately, using the exponential of a polynomial function to represent the underlying tailing of the larger peaks. The peak at 4655 keV could not be detected by alpha-particle spectrometry, while {gamma}-ray spectrometry confirms that its intensity is much lower than expected from literature.

  10. Particle and light fragment emission in peripheral heavy ion collisions at Fermi energies

    Science.gov (United States)

    Piantelli, S.; Maurenzig, P. R.; Olmi, A.; Bardelli, L.; Bartoli, A.; Bini, M.; Casini, G.; Coppi, C.; Mangiarotti, A.; Pasquali, G.; Poggi, G.; Stefanini, A. A.; Taccetti, N.; Vanzi, E.

    2006-09-01

    A systematic investigation of the average multiplicities of light charged particles and intermediate mass fragments emitted in peripheral and semiperipheral collisions is presented as a function of the beam energy, violence of the collision, and mass of the system. The data have been collected with the FIASCO setup in the reactions Nb93+Nb93 at (17,23,30,38)A MeV and Sn116+Sn116 at (30,38)A MeV. The midvelocity emission has been separated from the emission of the projectile-like fragment. This last component appears to be compatible with an evaporation from an equilibrated source at normal density, as described by the statistical code GEMINI at the appropriate excitation energy. On the contrary, the midvelocity emission presents remarkable differences in both the dependence of the multiplicities on the energy deposited in the midvelocity region and the isotopic composition of the emitted light charged particles.

  11. Particle and light fragment emission in peripheral heavy ion collisions at Fermi energies

    CERN Document Server

    Piantelli, S; Olmi, A; Bardelli, L; Bartoli, A; Bini, M; Casini, G; Coppi, C; Mangiarotti, A; Pasquali, G; Poggi, G; Stefanini, A A; Taccetti, N; Vanzi, E

    2006-01-01

    A systematic investigation of the average multiplicities of light charged particles and intermediate mass fragments emitted in peripheral and semiperipheral collisions is presented as a function of the beam energy, violence of the collision and mass of the system. The data have been collected with the "Fiasco" setup in the reactions 93Nb+93Nb at 17, 23, 30, 38AMeV and 116Sn+116Sn at 30, 38AMeV. The midvelocity emission has been separated from the emission of the projectile-like fragment. This last component appears to be compatible with an evaporation from an equilibrated source at normal density, as described by the statistical code Gemini at the appropriate excitation energy. On the contrary, the midvelocity emission presents remarkable differences for what concerns both the dependence of the multiplicities on the energy deposited in the midvelocity region and the isotopic composition of the emitted light charged particles.

  12. Emission factors and source apportionment for abrasion particles produced by road traffic

    Science.gov (United States)

    Bukowiecki, N.; Lienemann, P.; Figi, R.; Hill, M.; Richard, A.; Furger, M.; Rickers, K.; Cliff, S. S.; Baltensperger, U.; Gehrig, R.

    2009-04-01

    Particle emissions of road traffic are generally associated with fresh exhaust emissions only. However, recent studies identified a clear contribution of non-exhaust emissions to the PM10 load of the ambient air. These emissions consist of particles produced by abrasion from brakes, road wear, tire wear, as well as resuspension of deposited road dust. For many urban environments, quantitative information about the contributions of the individual abrasion processes is still scarce. For effective PM10 reduction scenarios it is of particular interest to know whether road wear, resuspension or fresh abrasion from vehicles is dominating the non-exhaust PM10 contribution. In Switzerland, the emissions of road traffic abrasion particles into the ambient air were characterized in the project APART (Abrasion Particles produced by Road Traffic). The project aimed at finding the contribution of the non-exhaust sources to total traffic-related PM10 and PM2.5 for different traffic conditions, by determining specific elemental fingerprint signatures for the various sources. This was achieved by hourly elemental mass concentration measurements in three size classes (2.5-10, 1-2.5 and 0.1-1 micrometers) with a rotating drum impactor (RDI) and subsequent synchrotron radiation X-ray fluorescence spectrometry (SR-XRF). The elemental fingerprint measurements were embedded into a large set of aerosol, gas phase, meteorological and traffic count measurements. To identify traffic related emissions, measurements were performed upwind and downwind of selected roads. For a better investigation of road wear, a road wear simulator was applied in additional experiments. This allows for the identification and quantification of the different source contributions by means of source-receptor modeling, and for the calculation of real-world emission factors for the individual abrasion sources. The preliminary analysis of hourly resolved trace element measurements in a street canyon in Zürich showed

  13. Biased impurity tunneling current emission spectrum in the presence of quasi-particle interaction

    Science.gov (United States)

    Maslova, N. S.; Arseyev, P. I.; Mantsevich, V. N.

    2016-09-01

    We performed theoretical investigations of the tunneling current noise spectra through single-level impurity in the presence of quasi-particle (electron-phonon) interaction by means of the non-equilibrium Green function formalism. We demonstrated a fundamental link between quantum noise in tunneling contact and light emission processes. We calculated tunneling current noise spectra through a single level impurity atom both in the presence and in the absence of quasi-particle interaction for a finite bias voltage and identified it as a source of experimentally observed light emission from bias STM contacts. The results turn out to be sensitive to the tunneling contact parameters. Our findings provide important insight into the nature of non-equilibrium electronic transport in tunneling junctions with quasi-particle interaction.

  14. Atmospheric number size distributions of soot particles and estimation of emission factors

    Directory of Open Access Journals (Sweden)

    D. Rose

    2006-01-01

    Full Text Available Number fractions of externally mixed particles of four different sizes (30, 50, 80, and 150 nm in diameter were measured using a Volatility Tandem DMA. The system was operated in a street canyon (Eisenbahnstrasse, EI and at an urban background site (Institute for Tropospheric Research, IfT, both in the city of Leipzig, Germany as well as at a rural site (Melpitz (ME, a village near Leipzig. Intensive campaigns of 3–5 weeks each took place in summer 2003 as well as in winter 2003/04. The data set thus obtained provides mean number fractions of externally mixed soot particles of atmospheric aerosols in differently polluted areas and different seasons (e.g. at 80 nm on working days, 60% (EI, 22% (IfT, and 6% (ME in summer and 26% (IfT, and 13% (ME in winter. Furthermore, a new method is used to calculate the size distribution of these externally mixed soot particles from parallel number size distribution measurements. A decrease of the externally mixed soot fraction with decreasing urbanity and a diurnal variation linked to the daily traffic changes demonstrate, that the traffic emissions have a significant impact on the soot fraction in urban areas. This influence becomes less in rural areas, due to atmospheric mixing and transformation processes. For estimating the source strength of soot particles emitted by vehicles (veh, soot particle emission factors were calculated using the Operational Street Pollution Model (OSPM. The emission factor for an average vehicle was found to be (1.5±0.4·1014 #(km·veh. The separation of the emission factor into passenger cars ((5.8±2·1013} #(km·veh and trucks ((2.5±0.9·1015 #(km·veh yielded in a 40-times higher emission factor for trucks compared to passenger cars.

  15. Exhaust particle and NOx emission performance of an SCR heavy duty truck operating in real-world conditions

    Science.gov (United States)

    Saari, Sampo; Karjalainen, Panu; Ntziachristos, Leonidas; Pirjola, Liisa; Matilainen, Pekka; Keskinen, Jorma; Rönkkö, Topi

    2016-02-01

    Particle and NOx emissions of an SCR equipped HDD truck were studied in real-world driving conditions using the "Sniffer" mobile laboratory. Real-time CO2 measurement enables emission factor calculation for NOx and particles. In this study, we compared three different emission factor calculation methods and characterised their suitability for real-world chasing experiments. The particle number emission was bimodal and dominated by the nucleation mode particles (diameter below 23 nm) having emission factor up to 1 × 1015 #/kgfuel whereas emission factor for soot (diameter above 23 nm that is consistent with the PMP standard) was typically 1 × 1014 #/kgfuel. The effect of thermodenuder on the exhaust particles indicated that the nucleation particles consisted mainly of volatile compounds, but sometimes there also existed a non-volatile core. The nucleation mode particles are not controlled by current regulations in Europe. However, these particles consistently form under atmospheric dilution in the plume of the truck and constitute a health risk for the human population that is exposed to those. Average NOx emission was 3.55 g/kWh during the test, whereas the Euro IV emission limit over transient testing is 3.5 g NOx/kWh. The on-road emission performance of the vehicle was very close to the expected levels, confirming the successful operation of the SCR system of the tested vehicle. Heavy driving conditions such as uphill driving increased both the NOx and particle number emission factors whereas the emission factor for soot particle number remains rather constant.

  16. Measurement of Black Carbon and Particle Number Emission Factors from Individual Heavy-Duty Trucks

    Energy Technology Data Exchange (ETDEWEB)

    Ban-Weiss, George A.; Lunden, Melissa M.; Kirchstetter, Thomas W.; Harley, Robert A.

    2009-02-02

    Emission factors for black carbon (BC) and particle number (PN) were measured from 226 individual heavy-duty (HD) diesel-fueled trucks driving through a 1 km-long California highway tunnel in August 2006. Emission factors were based on concurrent increases in BC, PN, and CO{sub 2}B concentrations (measured at 1 Hz) that corresponded to the passage of individual HD trucks. The distributions of BC and PN emission factors from individual HD trucks are skewed, meaning that a large fraction of pollution comes from a small fraction of the in-use vehicle fleet. The highest-emitting 10% of trucks were responsible for {approx} 40% of total BC and PN emissions from all HD trucks. BC emissions were log-normally distributed with a mean emission factor of 1.7 g kg {sup -1} and maximum values of {approx} 10 g kg{sup -1}. Corresponding values for PN emission factors were 4.7 x 10{sup 15} and 4 x 10{sup 16} kg{sup -1}. There was minimal overlap among high-emitters of these two pollutants: only 1 of the 226 HD trucks measured was found to be among the highest 10% for both BC and PN. Monte Carlo resampling of the distribution of BC emission factors observed in this study revealed that uncertainties (1{sigma}) in extrapolating from a random sample of n HD trucks to a population mean emission factor ranged from {+-} 43% for n = 10 to {+-} 8% for n = 300, illustrating the importance of sufficiently large vehicle sample sizes in emissions studies. Studies with low sample sizes are also more easily biased due to misrepresentation of high-emitters. As vehicles become cleaner on average in future years, skewness of the emissions distributions will increase, and thus sample sizes needed to extrapolate reliably from a subset of vehicles to the entire in-use vehicle fleet are expected to become more of a challenge.

  17. Measurement of black carbon and particle number emission factors from individual heavy-duty trucks.

    Science.gov (United States)

    Ban-Weiss, George A; Lunden, Melissa M; Kirchstetter, Thomas W; Harley, Robert A

    2009-03-01

    Emission factors for black carbon (BC) and particle number (PN) were measured from 226 individual heavy-duty (HD) diesel trucks driving through a 1-km-long California highway tunnel in August 2006. Emission factors were based on concurrent increases in BC, PN, and CO2 concentrations (measured at 1 Hz) that corresponded to the passage of individual HD trucks. The distributions of BC and PN emission factors from individual HD trucks are skewed, meaning that a large fraction of pollution comes from a small fraction of the in-use vehicle fleet. The highest-emitting 10% of trucks were responsible for approximately 40% of total BC and PN emissions from all HD trucks. BC emissions were log-normally distributed with a mean emission factor of 1.7 g kg(-1) and maximum values of approximately 10 g kg(-1). Corresponding values for PN emission factors were 4.7 x 10(15) and 4 x 10(16) # kg(-1). There was minimal overlap among high-emitters of these two pollutants: only 1 of the 226 HD trucks measured was found to be among the highest 10% for both BC and PN. Monte Carlo resampling of the distribution of BC emission factors observed in this study revealed that uncertainties (1sigma) in extrapolating from a random sample of n HD trucks to a population mean emission factor ranged from +/- 43% for n=10 to +/- 8% for n=300, illustrating the importance of vehicle sample sizes in emissions studies. When n=10, sample means are more likely to be biased due to misrepresentation of high-emitters. As vehicles become cleaner on average in the future, skewness of the emissions distributions will increase, and thus sample sizes needed to extrapolate reliably from a subset of vehicles to the entire in-use vehicle fleet will become more of a challenge.

  18. Charting the invisible in phase space (Abstract only)

    Indian Academy of Sciences (India)

    Alvaro de Rujula

    2012-06-01

    One challenge in particle physics is that not all the momenta relevant to many processes are observable. Some particles are nearly invisible (neutrinos and hypothetical neutralinos), others escape undetected down the beam pipes of colliders. One faces the task of extracting the maximum information (e.g. on the mass of the unobserved particles) from a set of more unknowns than constraining energy–momentum conservation equations. We study the simplest realistic case of current interest: single- production at a hadron collider, followed by its leptonic decay. We derive and discuss the statistically-optimal ‘singularity variable’ relevant to the measurement of the mass. In spite of its simplicity, this process is fairly non-trivial and constitutes a good ‘training’ example for the scrutiny of phenomena involving invisible objects. Our graphical analysis of the phase space is akin to that of a Dalitz plot, extended to such processes.

  19. Airborne measurements of trace gas and aerosol particle emissions from biomass burning in Amazonia

    Science.gov (United States)

    Guyon, P.; Frank, G. P.; Welling, M.; Chand, D.; Artaxo, P.; Rizzo, L.; Nishioka, G.; Kolle, O.; Fritsch, H.; Silva Dias, M. A. F.; Gatti, L. V.; Cordova, A. M.; Andreae, M. O.

    2005-11-01

    As part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Smoke, Aerosols, Clouds, Rainfall, and Climate) 2002 campaign, we studied the emission of carbon monoxide (CO), carbon dioxide (CO2), and aerosol particles from Amazonian deforestation fires using an instrumented aircraft. Emission ratios for aerosol number (CN) relative to CO (ERCN/CO) fell in the range 14-32 cm-3 ppb-1 in most of the investigated smoke plumes. Particle number emission ratios have to our knowledge not been previously measured in tropical deforestation fires, but our results are in agreement with values usually found from tropical savanna fires. The number of particles emitted per amount biomass burned was found to be dependent on the fire conditions (combustion efficiency). Variability in ERCN/CO between fires was similar to the variability caused by variations in combustion behavior within each individual fire. This was confirmed by observations of CO-to-CO2 emission ratios (ERCO/CO2), which stretched across the same wide range of values for individual fires as for all the fires observed during the sampling campaign, reflecting the fact that flaming and smoldering phases are present simultaneously in deforestation fires. Emission factors (EF) for CO and aerosol particles were computed and a correction was applied for the residual smoldering combustion (RSC) fraction of emissions that are not sampled by the aircraft, which increased the EF by a factor of 1.5-2.1. Vertical transport of smoke from the boundary layer (BL) to the cloud detrainment layer (CDL) and the free troposphere (FT) was found to be a very common phenomenon. We observed a 20% loss in particle number as a result of this vertical transport and subsequent cloud processing, attributable to in-cloud coagulation. This small loss fraction suggests that this mode of transport is very efficient in terms of particle numbers and occurs mostly via non-precipitating clouds. The detrained aerosol particles

  20. Influence of Neutron Shell Closure (Nc=126) on Prescission Particle Emission of Fissioning Systems 216,224Th

    Institute of Scientific and Technical Information of China (English)

    叶巍

    2003-01-01

    The effect of neutron shell closure Nc = 126 on the prescission-particle emission of 216Th and 224Th nuclei is investigated within the framework of an extensive Smoluchowski equation. It is found that there is a large difference in the prescission neutron multiplicity for the two Th nuclei, indicating a strong shell effect in neutron emission. Moreover, shell effects on particle emission are also investigated as functions of excitation energy,angular momentum and nuclear viscosity. The results show that with increasing excitation energy shell effects in prefission neutron evolve from continual strength to gradual weakness. Both high angular momenta and low viscosity weaken the shell effects on the particle emission.

  1. Invisible Web研究综述%An Overview of Invisible Web

    Institute of Scientific and Technical Information of China (English)

    黄晓冬

    2004-01-01

    本文对有关Invisible Web的内容进行了全面、详细地介绍.首先论述了什么是Invisible Web以及为什么要研究Invisible Web,同时介绍了两个相关概念;其次对Invisible Web不可见的原因加以分析;对Invisible Web 的类型进行了划分;介绍了Invisible Web的检索工具;最后总结了Invisible Web研究的方向.

  2. Invisible QCD as Dark Energy

    CERN Document Server

    Alexander, Stephon; Yang, Zhi

    2016-01-01

    We account for the late time acceleration of the Universe by extending the QCD color to a $SU(3)$ invisible sector (IQCD). If the Invisible Chiral symmetry is broken in the early universe, a condensate of dark pions (dpions) and dark gluons (dgluons) forms. The condensate naturally forms due to strong dynamics similar to the Nambu--Jona-Lasinio mechanism. As the Universe evolves from early times to present times the interaction energy between the dgluon and dpion condensate dominates with a negative pressure equation of state and causes late time acceleration. We conclude with a stability analysis of the coupled perturbations of the dark pions and dark gluons.

  3. Particle-Bound PAH Emission from the Exhaust of Combustion Chamber

    Science.gov (United States)

    Asgari Lamjiri, M.; Medrano, Y. S.; Guillaume, D. W.; Khachikian, C. S.

    2013-12-01

    reaction longer and also leads to a more complete combustion. The preliminary results from particle analyzer show that the abundance ratio of smaller particles to larger particles increases at higher swirl numbers. For example, at swirl 86, the abundance ratio of 0.3 micron particles to 0.7 micron particles was 400 while at swirl 0, this ratio was 35. Smaller particles have higher specific surface area which allows for more PAH adsorption. The preliminary results show that operating the jet engine at higher swirl numbers can have positive or negative effects on particle-bound PAH emissions. Higher temperature and residence time as well as better mixture of fuel and air can reduce PAH emission while generating more small size particles can increase surface available for PAH adsorption and, as a result, increases PAH emission. In future experiments, particle-bound PAHs of different swirl numbers will be compared in order to find a swirl number range which generates fewer Particle-bound PAHs.

  4. A Phenomenological Analysis of the Invisibility Syndrome

    Science.gov (United States)

    Tovar-Murray, Darrick; Tovar-Murray, Maria

    2012-01-01

    Interpretative phenomenological analysis was used to explore 10 African American men's perceptions of invisibility. Participants perceived invisibility as an extra unwarranted burden that is accompanied by feelings of hopelessness, anxiety, and anger. Participants also coped with invisibility by finding safe havens within the Black community.…

  5. Characterization of decay and emission rates of ultrafine particles in indoor ice rink.

    Science.gov (United States)

    Kim, J; Lee, K

    2013-08-01

    The purposes of this study were to determine indoor ultrafine particle (UFP, diameter DiSCmini were 0.54 ± 0.21/h and 0.85 ± 0.34/h, respectively. The average decay rate of UFP surface area concentration was 0.33 ± 0.15/h. The average emission rates of UFP number concentrations measured by P-Trak and DiSCmini were 1.2 × 10(14) ± 6.5 × 10(13) particles/min and 3.3 × 10(14) ± 2.4 × 10(14) particles/min, respectively. The average emission rate of UFP surface area concentration was 3.1 × 10(11) ± 2.0 × 10(11) μm(2)/min. UFP emission rate was associated with resurfacer age. DiSCmini measured higher decay and emission rates than P-Trak due to their different measuring mechanisms and size ranges.

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

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2010-11-01

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

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

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

    log10 F=0.48 · U+2.21

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

  7. Acoustic emissions for particle sizing of powders through signal processing techniques

    Energy Technology Data Exchange (ETDEWEB)

    Bastari, A.; Cristalli, C.; Morlacchi, R.; Pomponi, E. [Loccioni Group (Italy)

    2011-04-15

    The present work introduces an innovative method for measuring particle size distribution of an airborne powder, based on the application of signal processing techniques to the acoustic emission signals produced by the impacts of the powder with specific metallic surfaces. The basic idea of the proposed methodology lies on the identification of the unknown relation between the acquired acoustic emission signals and the powder particle size distribution, by means of a multi-step procedure. In the first step, wavelet packet decomposition is used to extract useful features from the acoustic emission signals: the dimensionality of feature space is further reduced through multivariate data analysis techniques. As a final step, a neural network is properly trained to map the feature vector into the particle size distribution. The proposed solution has several advantages, such as low cost and low invasiveness which allow the system based on this technique to be easily integrated in pre-existing plants. It has been successfully applied to the PSD measurement of coal powder produced by grinding mills in a coal-fired power station, and the experimental results are reported in the paper. The measurement principle can also be applied to different particle sizing applications, whenever a solid powder is carried in air or in other gases.

  8. Biomass burning emissions of trace gases and particles in marine air at Cape Grim, Tasmania

    Science.gov (United States)

    Lawson, S. J.; Keywood, M. D.; Galbally, I. E.; Gras, J. L.; Cainey, J. M.; Cope, M. E.; Krummel, P. B.; Fraser, P. J.; Steele, L. P.; Bentley, S. T.; Meyer, C. P.; Ristovski, Z.; Goldstein, A. H.

    2015-12-01

    Biomass burning (BB) plumes were measured at the Cape Grim Baseline Air Pollution Station during the 2006 Precursors to Particles campaign, when emissions from a fire on nearby Robbins Island impacted the station. Measurements made included non-methane organic compounds (NMOCs) (PTR-MS), particle number size distribution, condensation nuclei (CN) > 3 nm, black carbon (BC) concentration, cloud condensation nuclei (CCN) number, ozone (O3), methane (CH4), carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), nitrous oxide (N2O), halocarbons and meteorology. During the first plume strike event (BB1), a 4 h enhancement of CO (max ~ 2100 ppb), BC (~ 1400 ng m-3) and particles > 3 nm (~ 13 000 cm-3) with dominant particle mode of 120 nm were observed overnight. A wind direction change lead to a dramatic reduction in BB tracers and a drop in the dominant particle mode to 50 nm. The dominant mode increased in size to 80 nm over 5 h in calm sunny conditions, accompanied by an increase in ozone. Due to an enhancement in BC but not CO during particle growth, the presence of BB emissions during this period could not be confirmed. The ability of particles > 80 nm (CN80) to act as CCN at 0.5 % supersaturation was investigated. The ΔCCN / ΔCN80 ratio was lowest during the fresh BB plume (56 ± 8 %), higher during the particle growth period (77 ± 4 %) and higher still (104 ± 3 %) in background marine air. Particle size distributions indicate that changes to particle chemical composition, rather than particle size, are driving these changes. Hourly average CCN during both BB events were between 2000 and 5000 CCN cm-3, which were enhanced above typical background levels by a factor of 6-34, highlighting the dramatic impact BB plumes can have on CCN number in clean marine regions. During the 29 h of the second plume strike event (BB2) CO, BC and a range of NMOCs including acetonitrile and hydrogen cyanide (HCN) were clearly enhanced and some enhancements in O3 were observed

  9. Fine particle emissions from biomass cookstoves : Evaluation of a new laboratory setup and comparison of three appliances

    OpenAIRE

    Garcìa Lòpez, Natxo

    2017-01-01

    It is estimated that around three billion people globally rely on traditional usage of biomass to cover their daily energy needs, which causes health and social inequality problems and contributes to global warming. Thus, the study of particle emissions from cookstoves provides important information that can help improve global welfare.   This study aims to (a) evaluate a new laboratory setup for measurement of particle emissions from cookstoves and (b) use this setup to compare the particle ...

  10. Characteristics of polycyclic aromatic hydrocarbon emissions of particles of various sizes from smoldering incense.

    Science.gov (United States)

    Yang, T T; Lin, T S; Wu, J J; Jhuang, F J

    2012-02-01

    Release of polycyclic aromatic hydrocarbons (PAHs) in particles of various sizes from smoldering incenses was determined. Among the three types of incense investigated, yielding the total PAH emission rate and factor ranges for PM0.25 were 2,139.7-6,595.6 ng/h and 1,762.2-8,094.9 ng/g, respectively. The PM0.25/PM2.5 ratio of total PAH emission factors and rates from smoldering three incenses was greater than 0.92. This study shows that total particle PAH emission rates and factors were mainly incenses. The benzo[a]pyrene accounted for 65.2%-68.0% of the total toxic equivalency emission factor of PM2.5 for the three incenses. Experimental results clearly indicate that the PAH emission rates and factors were influenced significantly by incense composition, including carbon and hydrogen content. The study concludes that smoldering incense with low atomic hydrogen/carbon ratios minimized the production of total polycyclic aromatic hydrocarbons of both PM2.5 and PM0.25.

  11. Isoprene in poplar emissions: effects on new particle formation and OH concentrations

    Directory of Open Access Journals (Sweden)

    A. Kiendler-Scharr

    2012-01-01

    Full Text Available Stress-induced volatile organic compound (VOC emissions from transgenic Grey poplar modified in isoprene emission potential were used for the investigation of photochemical secondary organic aerosol (SOA formation. In poplar, acute ozone stress induces the emission of a wide array of VOCs dominated by sesquiterpenes and aromatic VOCs. Constitutive light-dependent emission of isoprene ranged between 66 nmol m−2 s−1 in non-transgenic controls (wild type WT and nearly zero (<0.5 nmol m−2 s−1 in isoprene emission-repressed plants (line RA22, respectively. Nucleation rates of up to 3600 cm−3 s−1 were observed in our experiments. In the presence of isoprene new particle formation was suppressed compared to non-isoprene containing VOC mixtures. Compared to isoprene/monoterpene systems emitted from other plants the suppression of nucleation by isoprene was less effective for the VOC mixture emitted from stressed poplar. This is explained by the observed high efficiency of new particle formation for emissions from stressed poplar. Direct measurements of OH in the reaction chamber revealed that the steady state concentration of OH is lower in the presence of isoprene than in the absence of isoprene, supporting the hypothesis that isoprenes' suppressing effect on nucleation is related to radical chemistry. In order to test whether isoprene contributes to SOA mass formation, fully deuterated isoprene (C5D8 was added to the stress-induced emission profile of an isoprene free poplar mutant. Mass spectral analysis showed that, despite the isoprene-induced suppression of particle formation, fractions of deuterated isoprene were incorporated into the SOA. A fractional mass yield of 2.3% of isoprene was observed. Future emission changes due to land use and climate change may therefore affect both gas phase oxidation capacity and new particle number formation.

  12. Isoprene in poplar emissions: effects on new particle formation and OH concentrations

    Directory of Open Access Journals (Sweden)

    A. Kiendler-Scharr

    2011-08-01

    Full Text Available Stress-induced volatile organic compound (VOC emissions from transgenic Grey poplar, modified in isoprene emission potential were used for the investigation of photochemical secondary organic aerosol (SOA formation. Nucleation rates of up to 3600 cm−3 s−1 were observed in our experiments. In poplar, acute ozone stress induces the emission of a wide array of VOCs dominated by sesquiterpenes and aromatic VOCs. Constitutive light-dependent emission of isoprene ranged between 66 nmol m−2 s−1 in non-transgenic controls (wild type WT and nearly zero (<0.5 nmol m−2 s−1 in isoprene emission-repressed lines (line RA22, respectively. In the presence of isoprene new particle formation was suppressed compared to non-isoprene containing VOC mixtures. Compared to isoprene/monoterpene systems emitted from other plants the suppression of nucleation by isoprene was less effective for the VOC mixture emitted from stressed poplar. This is explained by the observed high efficiency of new particle formation for emissions from stressed poplar. Direct measurements of OH in the reaction chamber revealed that the steady state concentration of OH is lower in the presence of isoprene than in the absence of isoprene, supporting the hypothesis that isoprenes' suppressing effect on nucleation is related to radical chemistry. In order to test whether isoprene contributes to SOA mass formation, fully deuterated isoprene (C5D8 was added to the stress-induced emission profile of an isoprene free poplar mutant. Mass spectral analysis showed that, despite the isoprene-induced suppression of particle formation, fractions of deuterated isoprene were incorporated into the SOA. A fractional mass yield of 2.3 % of isoprene was observed. Future emission changes due to land use and climate change may therefore affect both gas phase oxidation capacity and new particle number formation.

  13. Characteristics of SME biodiesel-fueled diesel particle emissions and the kinetics of oxidation.

    Science.gov (United States)

    Jung, Heejung; Kittelson, David B; Zachariah, Michael R

    2006-08-15

    Biodiesel is one of the most promising alternative diesel fuels. As diesel emission regulations have become more stringent, the diesel particulate filter (DPF) has become an essential part of the aftertreatment system. Knowledge of kinetics of exhaust particle oxidation for alternative diesel fuels is useful in estimating the change in regeneration behavior of a DPF with such fuels. This study examines the characteristics of diesel particulate emissions as well as kinetics of particle oxidation using a 1996 John Deere T04045TF250 off-highway engine and 100% soy methyl ester (SME) biodiesel (B100) as fuel. Compared to standard D2 fuel, this B100 reduced particle size, number, and volume in the accumulation mode where most of the particle mass is found. At 75% load, number decreased by 38%, DGN decreased from 80 to 62 nm, and volume decreased by 82%. Part of this decrease is likely associated with the fact that the particles were more easily oxidized. Arrhenius parameters for the biodiesel fuel showed a 2-3times greater frequency factor and approximately 6 times higher oxidation rate compared to regular diesel fuel in the range of 700-825 degrees C. The faster oxidation kinetics should facilitate regeneration when used with a DPF.

  14. Light Charged Particle Emission and the Giant Dipole Resonance in Ce Nucleus

    Science.gov (United States)

    Gramegna, F.; Barlini, S.; Kravchuk, V. L.; Lanchais, A. L.; Wieland, O.; Bracco, A.; Moroni, A.; Casini, G.; Benzoni, G.; Blasi, N.; Brambilla, S.; Brekiesz, M.; Bruno, M.; Camera, F.; Chiari, M.; Crespi, F.; Geraci, E.; Guiot, B.; Kmiecik, M.; Leoni, S.; Maj, A.; Mastinu, P. F.; Million, B.; Nannini, A.; Ordine, A.; Vannini, G.

    2005-04-01

    The 132Ce compound nucleus was formed in fusion reactions 64Ni + 68Zn and 16O + 116Sn at different excitation energies. High energy γ -rays have been measured in coincidence with Evaporation Residues (ER) in these reactions. At the same time Light Charged Particles (LCP) were measured with the same gate on ER for all the reactions in order to verify and compare the amount of pre-equilibrium emission using mass-symmetric and mass-asymmetric entrance channels. Results on α -particle spectra will be presented together with a moving source fit analysis.

  15. Imaging Invisible Flames Without Additives

    Science.gov (United States)

    Weiland, Karen J.

    1996-01-01

    Image intensifiers, video cameras, and image-data-processing computers used to study combustion. Possible to view and analyze methane, hydrogen, and other flames dim or invisible to human eye and difficult to image by use of conventional photographic and video cameras.

  16. Invisibility cloaking in weak scattering

    NARCIS (Netherlands)

    Setälä, Tero; Hakkarainen, Timo; Friberg, Ari T.; Hoenders, Bernhard J.

    2010-01-01

    We consider invisibility cloaking of a slab object in scalar wave theory within the first-order Born approximation. We show that in the forward direction cloaking is achieved for any object slab and incident field, whereas in the backward direction cloaking is possible at least for self-imaging fiel

  17. Impacts of natural emission sources on particle pollution levels in Europe

    Science.gov (United States)

    Liora, Natalia; Poupkou, Anastasia; Giannaros, Theodore M.; Kakosimos, Konstantinos E.; Stein, Olaf; Melas, Dimitrios

    2016-07-01

    The main objective of this work is the study of the impact of windblown dust, sea-salt aerosol and biogenic emissions on particle pollution levels in Europe. The Natural Emissions MOdel (NEMO) and the modelling system consisted of the Weather Research and Forecasting model (WRF) and the Comprehensive Air Quality model with extensions (CAMx) were applied in a 30 km horizontal resolution grid, which covered Europe and the adjacent areas for the year 2009. Air quality simulations were performed for different emission scenarios in order to study the contribution of each natural emission source individually and together to air quality levels in Europe. The simulations reveal that the exclusion of windblown dust emissions decreases the mean seasonal PM10 levels by more than 3.3 μg/m3 (∼20%) in the Eastern Mediterranean during winter while an impact of 3 μg/m3 was also found during summer. The results suggest that sea-salt aerosol has a significant effect on PM levels and composition. Eliminating sea-salt emissions reduces PM10 seasonal concentrations by around 10 μg/m3 in Mediterranean Sea during summer while a decrease of up to 6 μg/m3 is found in Atlantic Ocean during autumn. Sea-salt particles also interact with the anthropogenic component and therefore their absence in the atmosphere decreases significantly the nitrates in aerosols where shipping activities are present. The exclusion of biogenic emissions in the model runs leads to a significant reduction of secondary organic aerosols of more than 90% while an increase in PM2.5 levels in central Europe and Eastern Mediterranean is found due to their interaction with anthropogenic component.

  18. Diesel particle filter and fuel effects on heavy-duty diesel engine emissions.

    Science.gov (United States)

    Ratcliff, Matthew A; Dane, A John; Williams, Aaron; Ireland, John; Luecke, Jon; McCormick, Robert L; Voorhees, Kent J

    2010-11-01

    The impacts of biodiesel and a continuously regenerated (catalyzed) diesel particle filter (DPF) on the emissions of volatile unburned hydrocarbons, carbonyls, and particle associated polycyclic aromatic hydrocarbons (PAH) and nitro-PAH, were investigated. Experiments were conducted on a 5.9 L Cummins ISB, heavy-duty diesel engine using certification ultra-low-sulfur diesel (ULSD, S ≤ 15 ppm), soy biodiesel (B100), and a 20% blend thereof (B20). Against the ULSD baseline, B20 and B100 reduced engine-out emissions of measured unburned volatile hydrocarbons and PM associated PAH and nitro-PAH by significant percentages (40% or more for B20 and higher percentage for B100). However, emissions of benzene were unaffected by the presence of biodiesel and emissions of naphthalene actually increased for B100. This suggests that the unsaturated FAME in soy-biodiesel can react to form aromatic rings in the diesel combustion environment. Methyl acrylate and methyl 3-butanoate were observed as significant species in the exhaust for B20 and B100 and may serve as markers of the presence of biodiesel in the fuel. The DPF was highly effective at converting gaseous hydrocarbons and PM associated PAH and total nitro-PAH. However, conversion of 1-nitropyrene by the DPF was less than 50% for all fuels. Blending of biodiesel caused a slight reduction in engine-out emissions of acrolein, but otherwise had little effect on carbonyl emissions. The DPF was highly effective for conversion of carbonyls, with the exception of formaldehyde. Formaldehyde emissions were increased by the DPF for ULSD and B20.

  19. Determination of single particle mass spectral signatures from light-duty vehicle emissions.

    Science.gov (United States)

    Sodeman, David A; Toner, Stephen M; Prather, Kimberly A

    2005-06-15

    observed in the chemical composition of particles emitted within the different car categories as well as for the same car operating under different driving conditions. Two-minute temporal resolution measurements provide information on the chemical classes as they evolved during the FTP cycle. The first two minutes of the cold start produced more than 5 times the number of particles than any other portion of the cycle, with one class of ultrafine particles (EC coupled with Ca, OC, and phosphate) preferentially produced. By number, the three EC with Ca classes (which also contained OC, phosphate, and sulfate) were the most abundant classes produced by the nonsmoking vehicles. The smoker category produced the highest number of particles, with the dominant classes being OC comprised of substituted monoaromatic compounds and PAHs, coupled with Ca and phosphate, thus suggesting used lubricating oil was associated with many of these particles. These studies show, by number, EC particles dominate gasoline emissions in the ultrafine size range particularlyforthe lowest emitting newer vehicles, suggesting the EC signature alone cannot be used as a unique tracer for diesels. This represents the first report of high time- and size-resolved chemical composition data showing the mixing state of nonrefractory elements in particles such as EC for vehicle emissions during dynamometer source testing.

  20. The Sun and its Planets as detector for invisible matter

    CERN Document Server

    Bertolucci, Sergio; Hofmann, Sebastian; Maroudas, Marios

    2016-01-01

    Gravitational lensing / deflection of invisible streaming matter towards the Sun could explain the puzzling solar flares and the unexplained solar emission in the EUV. Assuming that this invisible matter has some form of interaction with normal matter and that there exist preferred directions in its flow, then one would expect a more pronounced solar activity at certain planetary heliocentric longitudes. This is best demonstrated in the case of the 3 inner planets, considering their relatively short revolution time in comparison to a solar cycle of about 11 years. We have analyzed the solar flares as well as the EUV emission. We observe statistically significant signals when one or more planets have heliocentric longitudes mainly between 230o and 300o. The broad velocity spectrum of the assumed constituents makes it at this stage difficult to identify its source(s) in space. More refined future analyses might increase the precision of the determination of the stream direction and some properties of its consti...

  1. Preequilibrium particle emission in 250 MeV {sup 16}O + {sup 116}Sn reaction

    Energy Technology Data Exchange (ETDEWEB)

    Barlini, S.; Kravchuk, V.L.; Gramegna, F. [INFN, Laboratori Nazionali di Legnaro Padova (Italy)] (and others)

    2005-07-01

    A certain progress in understanding the phenomenon of the Preequilibrium (fast) light charged particle and neutron Emission (PE) was achieved in the last two decades. However, there is a strong need to study systematically the dependence of the PE emission on the reaction mass asymmetry and the projectile energy. In the present work we present the results on the PE proton and alpha-particle multiplicities and the total energy loss of the composite system formed in fusion reaction E{sub b}eam=250 MeV (15.6 MeV/u) {sup 16}O + {sup 116}Sn. The experiment was performed at the Legnaro National Laboratory using a 1 ns (FWHM) pulsed beam provided by the TANDEM-ALPI acceleration system.

  2. Modeling of radio emission from a particle cascade in a magnetic field and its experimental validation

    Science.gov (United States)

    Zilles, Anne

    2017-03-01

    The SLAC T-510 experiment was designed to compare controlled laboratory measurements of radio emission of particle showers to predictions using particle-level simulations, which are relied upon in ultra-high-energy cosmic-ray air shower detection. Established formalisms for the simulation of radio emission physics, the "endpoint" formalism and the "ZHS" formalism, lead to results which can be explained by a superposition of magnetically induced transverse current radiation and charge-excess radiation due to the Askaryan effect. Here, we present the results of Geant4 simulations for the SLAC T-510 experiment, taking into account the details of the experimental setup (beam energy, target geometry and material, magnetic field configuration, and refraction effects) and their comparison to measured data with respect to e.g. signal polarisation, linearity with magnetic field, and angular distribution. We find that the microscopic calculations reproduce the measurements within uncertainties and describe the data well.

  3. Black hole emission of vector particles in (1+1) dimensions

    CERN Document Server

    Kruglov, S I

    2014-01-01

    We investigate the radiation of spin-1 particles by black holes in (1+1) dimensions within the Proca equation. The process is considered as quantum tunnelling of bosons through an event horizon. It is shown that the emission temperature for the Schwarzschild background geometry is the same as the Hawking temperature corresponding to scalar particles emission. We also obtain the radiation temperatures for the de Sitter, Rindler and Schwarzschild-de Sitter space-times. In a particular case when two horizons in Schwarzschild-de Sitter space-time coincides the Nariai temperature is recovered. The thermodynamical entropy of a black hole is calculated for Schwarzschild-de Sitter space-time having two horizons.

  4. Emission factors for carbonaceous particles and polycyclic aromatic hydrocarbons from residential coal combustion in China.

    Science.gov (United States)

    Chen, Yingjun; Sheng, Guoying; Bi, Xinhui; Feng, Yanli; Mai, Bixian; Fu, Jiamo

    2005-03-15

    Emission factors of carbonaceous particles, including black carbon (BC) and organic carbon (OC), and polycyclic aromatic hydrocarbons (PAHs) were determined for five coals, which ranged in maturity from sub-bituminous to anthracite. They were burned in the form of honeycomb briquettes in a residential coalstove, one of the most common fuel/stove combinations in China. Smoke samples were taken through dilution sampling equipment, with a high volume sampler that could simultaneously collect emissions in both particulate and gaseous phases, and a cascade impactor that could segregate particles into six fractions. Particulate BC and OC were analyzed by a thermal-optical method, and PAHs in emissions of both phases were analyzed by GC-MS. Burning of bituminous coals produced the highest emission factors of particulate matter (12.91 g/kg), BC (0.28 g/kg), OC (7.82 g/kg), and 20 PAHs (210.6 mg/kg) on the basis of burned dry ash-free (daf) coal, while the anthracite honeycomb-briquette was the cleanest household coal fuel. The size-segregated results show that more than 94% of the particles were submicron, and calculated mass median aerodynamic diameters (MMAD) of all particles were under 0.3 microm. Based on the coal consumption in the residential sector of China, 290.24 Gg (gigagrams) of particulate matter, 5.36 Gg of BC, 170.33 Gg of OC, and 4.72 Gg of 20 PAHs mass were emitted annually from household honeycomb-briquette burning during 2000. Anthracite coal should be selected preferentially and more advanced burning conditions should be applied in domestic combustion, from the viewpoint of both climate change and adverse health effects.

  5. Eddy covariance measurements and parameterisation of traffic related particle emissions in an urban environment

    Directory of Open Access Journals (Sweden)

    E. M. Mårtensson

    2006-01-01

    Full Text Available Urban aerosol sources are important due to the health effects of particles and their potential impact on climate. Our aim has been to quantify and parameterise the urban aerosol source number flux F (particles m−2 s−1, in order to help improve how this source is represented in air quality and climate models. We applied an aerosol eddy covariance flux system 118.0 m above the city of Stockholm. This allowed us to measure the aerosol number flux for particles with diameters >11 nm. Upward source fluxes dominated completely over deposition fluxes in the collected dataset. Therefore, the measured fluxes were regarded as a good approximation of the aerosol surface sources. Upward fluxes were parameterised using a traffic activity (TA database, which is based on traffic intensity measurements. The footprint (area on the surface from which sources and sinks affect flux measurements, located at one point in space of the eddy system covered road and building construction areas, forests and residential areas, as well as roads with high traffic density and smaller streets. We found pronounced diurnal cycles in the particle flux data, which were well correlated with the diurnal cycles in traffic activities, strongly supporting the conclusion that the major part of the aerosol fluxes was due to traffic emissions. The emission factor for the fleet mix in the measurement area EFfm=1.4±0.1×1014 veh−1 km−1 was deduced. This agrees fairly well with other studies, although this study has an advantage of representing the actual effective emission from a mixed vehicle fleet. Emission from other sources, not traffic related, account for a F0=15±18×106 m−2 s−1. The urban aerosol source flux can then be written as F=EFfmTA+F0. In a second attempt to find a parameterisation, the friction velocity U* normalised with the average friction velocity has been included, F=EF . This parameterisation results in a somewhat reduced emission factor, 1.3×1014 veh

  6. Indoor emission, dispersion and exposure of total particle-bound polycyclic aromatic hydrocarbons during cooking

    Science.gov (United States)

    Gao, Jun; Jian, Yating; Cao, Changsheng; Chen, Lei; Zhang, Xu

    2015-11-01

    Cooking processes highly contribute to indoor polycyclic aromatic hydrocarbon (PAH) pollution. High molecular weight and potentially carcinogenic PAHs are generally found attached to small particles, i.e., particulate phase PAHs (PPAHs). Due to the fact that indoor particle dynamics have been clear, describing the indoor dynamics of cooking-generated PPAHs within a specific time span is possible. This paper attempted to quantify the dynamic emission rate, simultaneous spatial dispersion and individual exposure of PPAHs using a cooking source. Experiments were conducted in a real-scale kitchen chamber to elucidate the time-resolved emission and effect of edible oil temperature and mass. Numerical simulations based on indoor particle dynamics were performed to obtain the spatial dispersion and individual inhalation intake of PPAHs under different emission and ventilation conditions. The present work examined the preheating cooking stage, at which edible oil is heated up to beyond its smoke point. The dynamic emission rate peak point occurred much earlier than the oil heating temperature. The total PPAH emission ranged from 2258 to 6578 ng upon heating 40-85 g of edible oil. The overall intake fraction by an individual within a period of 10 min, including 3 min for heating and 7 min for natural cooling, was generally ∼1/10,000. An important outcome of this work was that the overall intake fraction could be represented by multiplying the range hood escape efficiency by the inhalation-to-ventilation rate ratio, which would be no greater than the same ratio. The methodology and results of this work were extendible for the number-based assessment of PPAHs. This work is expected to help us understand the health risks due to inhalation exposure to cooking-generated PPAHs in the kitchen.

  7. Particle and NO{sub x} Emissions from a HVO-Fueled Diesel Engine

    Energy Technology Data Exchange (ETDEWEB)

    Happonen, M.

    2012-10-15

    Concerns about oil price, the strengthening climate change and traffic related health effects are all reasons which have promoted the research of renewable fuels. One renewable fuel candidate is diesel consisting of hydrotreated vegetable oils (HVO). The fuel is essentially paraffinic, has high cetane number (>80) and contains practically no oxygen, aromatics or sulphur. Furthermore, HVO fuel can be produced from various feedstocks including palm, soybean and rapeseed oils as well as animal fats. HVO has also been observed to reduce all regulated engine exhaust emissions compared to conventional diesel fuel. In this thesis, the effect of HVO fuel on engine exhaust emissions has been studied further. The thesis is roughly divided into two parts. The first part explores the emission reductions associated with the fuel and studies techniques which could be applied to achieve further emission reductions. One of the studied techniques was adjusting engine settings to better suit HVO fuel. The settings chosen for adjustments were injection pressure, injection timing, the amount of EGR and the timing of inlet valve closing (with constant inlet air mass flow, i.e. Miller timing). The engine adjustments were also successfully targeted to reduce either NO{sub x} or particulate emissions or both. The other applied emission reduction technique was the addition of oxygenate to HVO fuel. The chosen oxygenate was di-n-pentyl ether (DNPE), and tested fuel blend included 20 wt-% DNPE and 80 wt-% HVO. Thus, the oxygen content of the resulting blend was 2 wt-%. Reductions of over 25 % were observed in particulate emissions with the blend compared to pure HVO while NOx emissions altered under 5 %. On the second part of this thesis, the effect of the studied fuels on chosen surface properties of exhaust particles were studied using tandem differential mobility analyzer (TDMA) techniques and transmission electron microscopy (TEM). The studied surface properties were oxidizability and

  8. Relationship of shock-associated kilometric radio emission with metric type II bursts and energetic particles

    Energy Technology Data Exchange (ETDEWEB)

    Kahler, S.W.; Cliver, E.W.; Cane, H.V.

    1986-01-01

    Shock-associated (SA) events are a class of kilometric-wavelength solar radio bursts first observed with the ISEE-3 Radio Astronomy Experiment. These fast-drift events are typically associated with metric type II bursts and hypothesized that the SA events were due to electrons accelerated by coronal shocks. Compare SA events from 1978 to 1982 with metric type II bursts and solar energetic particle (SEP) events. Most metric type II bursts are not obviously associated with SA events at 1980 kHz. Metric type II bursts associated with magnetically well connected flares and SA emission are well correlated with SEP events; those without SA emission are poorly correlated with SEP events. The largest SEP events from flares at any longitude are well correlated with SAs. These results are consistent with the hypothesis that the escaping electrons giving rise to SA emission are accelerated in coronal shocks.

  9. Particle-Scale Modeling of Methane Emission during Pig Manure/Wheat Straw Aerobic Composting.

    Science.gov (United States)

    Ge, Jinyi; Huang, Guangqun; Huang, Jing; Zeng, Jianfei; Han, Lujia

    2016-04-19

    Inefficient aerobic composting techniques significantly contribute to the atmospheric methane (CH4) levels. Macro-scale models assuming completely aerobic conditions cannot be used to analyze CH4 generation in strictly anaerobic environments. This study presents a particle-scale model for aerobic pig manure/wheat straw composting that incorporates CH4 generation and oxidation kinetics. Parameter estimation revealed that pig manure is characterized by high CH4 yield coefficient (0.6414 mol CH4 mol(-1) Cman) and maximum CH4 oxidation rate (0.0205 mol CH4 kg(-1) VS(aero) h(-1)). The model accurately predicted CH4 emissions (R(2) = 0.94, RMSE = 2888 ppmv, peak time deviation = 0 h), particularly in the self-heating and cooling phases. During mesophilic and thermophilic stages, a rapid increase of CH4 generation (0.0130 mol CH4 kg(-1) VS h(-1)) and methanotroph inactivation were simulated, implying that additional measures should be performed during these phases to mitigate CH4 emissions. Furthermore, CH4 oxidation efficiency was related to oxygen permeation through the composting particles. Reducing the ambient temperature and extending the aeration duration can decrease CH4 emission, but the threshold temperature is required to trigger the self-heating phase. These findings provide insights into CH4 emission during composting and may inform responsible strategies to counteract climate change.

  10. Relating urban airborne particle concentrations to shipping using carbon based elemental emission ratios

    Science.gov (United States)

    Johnson, Graham R.; Juwono, Alamsyah M.; Friend, Adrian J.; Cheung, Hing-Cho; Stelcer, Eduard; Cohen, David; Ayoko, Godwin A.; Morawska, Lidia

    2014-10-01

    This study demonstrates a novel method for testing the hypothesis that variations in primary and secondary particle number concentration (PNC) in urban air are related to residual fuel oil combustion at a coastal port lying 30 km upwind, by examining the correlation between PNC and airborne particle composition signatures chosen for their sensitivity to the elemental contaminants present in residual fuel oil. Residual fuel oil combustion indicators were chosen by comparing the sensitivity of a range of concentration ratios to airborne emissions originating from the port. The most responsive were combinations of vanadium and sulphur concentration ([S], [V]) expressed as ratios with respect to black carbon concentration ([BC]). These correlated significantly with ship activity at the port and with the fraction of time during which the wind blew from the port. The average [V] when the wind was predominantly from the port was 0.52 ng m-3 (87%) higher than the average for all wind directions and 0.83 ng m-3 (280%) higher than that for the lowest vanadium yielding wind direction considered to approximate the natural background. Shipping was found to be the main source of V impacting urban air quality in Brisbane. However, contrary to the stated hypothesis, increases in PNC related measures did not correlate with ship emission indicators or ship traffic. Hence at this site ship emissions were not found to be a major contributor to PNC compared to other fossil fuel combustion sources such as road traffic, airport and refinery emissions.

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

    Science.gov (United States)

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

    2012-10-16

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

  12. Simulated restaurant cook exposure to emissions of PAHs, mutagenic aldehydes, and particles from frying bacon.

    Science.gov (United States)

    Jørgensen, Rikke Bramming; Strandberg, Bo; Sjaastad, Ann Kristin; Johansen, Arve; Svendsen, Kristin

    2013-01-01

    This study investigated the exposure of cooks to polycyclic aromatic hydrocarbons (PAHs), higher mutagenic aldehydes, total particles, and ultrafine particles during cooking. Experiments were performed by pan frying fresh and smoked bacon on both electric and gas stoves, and with the gas alone. Detailed analyses of PAHs were performed, with analyses of the levels of 32 different PAHs. A TSI-3939 scanning mobility particle sizer system was used to measure the ultrafine particles. The results showed that total PAHs were in the range of 270-300 ng/m(3) air. However, the smoked bacon experiment showed a somewhat different PAH pattern, whereby retene constituted about 10% of the total PAHs, which is a level similar to that of the abundant gas phase constituent phenanthrene. The reason for the elevated retene emissions is unknown. The total cancer risk, expressed as toxic equivalency factors, showed a somewhat higher risk on the electric stove (p decadienal were between 34 and 54 μg/m(3) air. The level of total particles was between 2.2 and 4.2 mg/m(3). Frying on a gas stove caused a statistically significant higher amount of ultrafine particles compared with frying on an electric stove. Large variations in the mobility diameter at peak particle concentration were found (74.4 nm-153.5 nm). The highest mobility diameter was found for frying on an electric stove. The gas flame itself showed a maximum production of 19.5-nm-sized particles and could not be the explanation for the difference between frying on the gas stove and frying on the electric stove. No single indicator for the exposure to cooking fume could be selected. Each compound should be measured independently to provide a comprehensive characterization of the cooking exposure.

  13. Characterization of fleet emissions from ships through multi-individual determination of size-resolved particle emissions in a coastal area

    Science.gov (United States)

    Westerlund, Jonathan; Hallquist, Mattias; Hallquist, Åsa M.

    2015-07-01

    Shipping is becoming a major source of particulate air pollution in coastal cities. Here we describe the use of a stationary measurement site to characterize nanoparticle emissions (5.6-560 nm) from a large ship fleet (154 ships) in a harbor region of an emission control area (ECA) under real-world dilution conditions. Emission factors (EFs) are described with respect to particle number (PN), mass (PM), size and volatility. Automatic Identification System data were used to obtain information on ship class, direction, speed and acceleration. Cargo and passenger ships had similar average EFs: 2.79 ± 0.19 vs. 2.35 ± 0.20 × 1016 # (kg fuel)-1 and 2550 ± 170 vs. 2200 ± 130 mg (kg fuel)-1 respectively. The number size distributions for cargo and passenger ships were unimodal, peaking at ∼40 nm. Tug-boats and pilots emitted smaller particles with lower EFPN and EFPM. For emissions of non-volatile particles from cargo and passenger ships EFPM increased with decreasing speed and acceleration while the EFPN decreased. The size distributions of the non-volatile particles for all ships contained a large mode at ∼10 nm. This peak is believed to be formed during plume aging. A detailed understanding of size-resolved particle emissions from individual ships will be important in designing appropriate emission regulations for coastal areas.

  14. Dark Matter from Late Invisible Decays to/of Gravitinos

    CERN Document Server

    Allahverdi, Rouzbeh; Queiroz, Farinaldo S; Strigari, Louis E; Wang, Mei-Yu

    2014-01-01

    In this work, we sift a simple supersymmetric framework of late invisible decays to/of the gravitino. We investigate two cases where the gravitino is the lightest supersymmetric particle or the next-to-lightest supersymmetric particle. The next-to-lightest supersymmetric particle decays into two dark matter candidates and has a long lifetime due to gravitationally suppressed interactions. However, because of the absence of any hadronic or electromagnetic products, it satisfies the tight bounds set by big bang nucleosynthesis and cosmic microwaved background. One or both of the dark matter candidates produced in invisible decays can contribute to the amount of dark radiation and suppress perturbations at scales that are being probed by the galaxy power spectrum and the Lyman-alpha forest data. We show that these constraints are satisfied in large regions of the parameter space and, as a result, the late invisible decays to/of the gravitino can be responsible for the entire dark matter relic abundance.

  15. Particle and gaseous emissions from compressed natural gas and ultralow sulphur diesel-fuelled buses at four steady engine loads.

    Science.gov (United States)

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

    2009-04-01

    Exhaust emissions from thirteen compressed natural gas (CNG) and nine ultralow sulphur diesel in-service transport buses were monitored on a chassis dynamometer. Measurements were carried out at idle and at three steady engine loads of 25%, 50% and 100% of maximum power at a fixed speed of 60 km h(-1). Emission factors were estimated for particle mass and number, carbon dioxide and oxides of nitrogen for two types of CNG buses (Scania and MAN, compatible with Euro 2 and 3 emission standards, respectively) and two types of diesel buses (Volvo Pre-Euro/Euro1 and Mercedez OC500 Euro3). All emission factors increased with load. The median particle mass emission factor for the CNG buses was less than 1% of that from the diesel buses at all loads. However, the particle number emission factors did not show a statistically significant difference between buses operating on the two types of fuel. In this paper, for the very first time, particle number emission factors are presented at four steady state engine loads for CNG buses. Median values ranged from the order of 10(12) particles min(-)(1) at idle to 10(15) particles km(-)(1) at full power. Most of the particles observed in the CNG emissions were in the nanoparticle size range and likely to be composed of volatile organic compounds The CO2 emission factors were about 20% to 30% greater for the diesel buses over the CNG buses, while the oxides of nitrogen emission factors did not show any difference due to the large variation between buses.

  16. Pre-equilibrium α-particle emission as a probe to study α-clustering in nuclei

    Science.gov (United States)

    Fotina, O. V.; Goncharov, S. A.; Eremenko, D. O.; Platonov, S. Yu.; Yuminov, O. A.; Kravchuk, V. L.; Gramegna, F.; Marchi, T.; Cinausero, M.; D'Agostino, M.; Bruno, M.; Baiocco, G.; Morelli, L.; Degerlier, M.; Casini, G.; Barlini, S.; Valdrè, S.; Piantelli, S.; Pasquali, G.; Bracco, A.; Camera, F.; Wieland, O.; Benzoni, G.; Blasi, N.; Giaz, A.; Corsi, A.; Fabris, D.

    2014-03-01

    A theoretical approach was developed to describe secondary particle emission in heavy ion collisions, with special regards to pre-equilibrium α-particle production. The probabilities of neutron, proton and α-particle emission have been evaluated for both the equilibrium and pre-equilibrium stages of the process. Effects due the possible cluster structure of the projectile which has been excited during the collisions have been experimentally evidenced studying the double differential cross sections of p and α-particles emitted in the E=250MeV 16O +116Sn reaction. Calculations within the present model with different clusterization probabilities have been compared to the experimental data.

  17. Particle emission rates during electrostatic spray deposition of TiO2 nanoparticle-based photoactive coating.

    Science.gov (United States)

    Koivisto, Antti J; Jensen, Alexander C Ø; Kling, Kirsten I; Kling, Jens; Budtz, Hans Christian; Koponen, Ismo K; Tuinman, Ilse; Hussein, Tareq; Jensen, Keld A; Nørgaard, Asger; Levin, Marcus

    2018-01-05

    Here, we studied the particle release rate during Electrostatic spray deposition of anatase-(TiO2)-based photoactive coating onto tiles and wallpaper using a commercially available electrostatic spray device. Spraying was performed in a 20.3m(3) test chamber while measuring concentrations of 5.6nm to 31μm-size particles and volatile organic compounds (VOC), as well as particle deposition onto room surfaces and on the spray gun user hand. The particle emission and deposition rates were quantified using aerosol mass balance modelling. The geometric mean particle number emission rate was 1.9×10(10)s(-1) and the mean mass emission rate was 381μgs(-1). The respirable mass emission-rate was 65% lower than observed for the entire measured size-range. The mass emission rates were linearly scalable (±ca. 20%) to the process duration. The particle deposition rates were up to 15h(-1) for coated with carbon, and Ag particles with size ranging from 60nm to ca. 5μm. As expected, no significant VOC emissions were observed as a result of spraying. Finally, we provide recommendations for exposure model parameterization. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  18. On-road particle number measurements using a portable emission measurement system (PEMS)

    Science.gov (United States)

    Gallus, Jens; Kirchner, Ulf; Vogt, Rainer; Börensen, Christoph; Benter, Thorsten

    2016-01-01

    In this study the on-road particle number (PN) performance of a Euro-5 direct-injection (DI) gasoline passenger car was investigated. PN emissions were measured using the prototype of a portable emission measurement system (PEMS). PN PEMS correlations with chassis dynamometer tests show a good agreement with a chassis dynamometer set-up down to emissions in the range of 1·1010 #/km. Parallel on-line soot measurements by a photo acoustic soot sensor (PASS) were applied as independent measurement technique and indicate a good on-road performance for the PN-PEMS. PN-to-soot ratios were 1.3·1012 #/mg, which was comparable for both test cell and on-road measurements. During on-road trips different driving styles as well as different road types were investigated. Comparisons to the world harmonized light-duty test cycle (WLTC) 5.3 and to European field operational test (euroFOT) data indicate the PEMS trips to be representative for normal driving. Driving situations in varying traffic seem to be a major contributor to a high test-to-test variability of PN emissions. However, there is a trend to increasing PN emissions with more severe driving styles. A cold start effect is clearly visible for PN, especially at low ambient temperatures down to 8 °C.

  19. Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation

    Directory of Open Access Journals (Sweden)

    D. V. Spracklen

    2010-05-01

    Full Text Available We synthesised observations of total particle number (CN concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300–2000 cm−3 in the marine boundary layer and free troposphere (FT and 1000–10 000 cm−3 in the continental boundary layer (BL. Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2–10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R2=0.46 but fail to explain the observed seasonal cycle (R2=0.1. The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=−88% unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=−25%. Simulated CN concentrations in the continental BL were also biased low (NMB=−74% unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one or kinetic-type mechanism (J proportional to sulfuric acid to the power two with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R2=0.3 than by increasing the number emission from primary anthropogenic sources (R2=0.18. The nucleation constants that resulted in best overall match between model and observed CN concentrations were

  20. Optical Neutrality: Invisibility without Cloaking

    CERN Document Server

    Hodges, Reed; Durach, Maxim

    2016-01-01

    We show that it is possible to design an invisible wavelength-sized metal-dielectric metamaterial object without evoking cloaking. Our approach is an extension of the neutral inclusion concept by Zhou and Hu [Phys.Rev.E 74, 026607 (2006)] to Mie scatterers. We demonstrate that an increase of metal fraction in the metamaterial leads to a transition from dielectric-like to metal-like scattering, which proceeds through invisibility or optical neutrality of the scatterer. Formally this is due to cancellation of multiple scattering orders, similarly to plasmonic cloaking introduced by Alu and Engheta [Phys.Rev.E 72, 016623 (2005)], but without introduction of the separation of the scatterer into cloak and hidden regions.

  1. Invisible Trojan-horse attack.

    Science.gov (United States)

    Sajeed, Shihan; Minshull, Carter; Jain, Nitin; Makarov, Vadim

    2017-08-21

    We demonstrate the experimental feasibility of a Trojan-horse attack that remains nearly invisible to the single-photon detectors employed in practical quantum key distribution (QKD) systems, such as Clavis2 from ID Quantique. We perform a detailed numerical comparison of the attack performance against Scarani-Ac´ın-Ribordy-Gisin (SARG04) QKD protocol at 1924 nm versus that at 1536 nm. The attack strategy was proposed earlier but found to be unsuccessful at the latter wavelength, as reported in N. Jain et al., New J. Phys. 16, 123030 (2014). However at 1924 nm, we show experimentally that the noise response of the detectors to bright pulses is greatly reduced, and show by modeling that the same attack will succeed. The invisible nature of the attack poses a threat to the security of practical QKD if proper countermeasures are not adopted.

  2. Performance Evaluation of Particle Sampling Probes for Emission Measurements of Aircraft Jet Engines

    Science.gov (United States)

    Lee, Poshin; Chen, Da-Ren; Sanders, Terry (Technical Monitor)

    2001-01-01

    Considerable attention has been recently received on the impact of aircraft-produced aerosols upon the global climate. Sampling particles directly from jet engines has been performed by different research groups in the U.S. and Europe. However, a large variation has been observed among published data on the conversion efficiency and emission indexes of jet engines. The variation results surely from the differences in test engine types, engine operation conditions, and environmental conditions. The other factor that could result in the observed variation is the performance of sampling probes used. Unfortunately, it is often neglected in the jet engine community. Particle losses during the sampling, transport, and dilution processes are often not discussed/considered in literatures. To address this issue, we evaluated the performance of one sampling probe by challenging it with monodisperse particles. A significant performance difference was observed on the sampling probe evaluated under different temperature conditions. Thermophoretic effect, nonisokinetic sampling and turbulence loss contribute to the loss of particles in sampling probes. The results of this study show that particle loss can be dramatic if the sampling probe is not well designed. Further, the result allows ones to recover the actual size distributions emitted from jet engines.

  3. MONDO: A neutron tracker for particle therapy secondary emission fluxes measurements

    Science.gov (United States)

    Marafini, M.; Patera, V.; Pinci, D.; Sarti, A.; Sciubba, A.; Spiriti, E.

    2016-07-01

    Cancer treatment is performed, in Particle Therapy, using accelerated charged particles whose high irradiation precision and conformity allows the tumor destruction while sparing the surrounding healthy tissues. Dose release monitoring devices using photons and charged particles produced by the beam interaction with the patient body have already been proposed, but no attempt based on the detection of the abundant secondary radiation neutron component has been made yet. The reduced attenuation length of neutrons yields a secondary particle sample that is larger in number when compared to photons and charged particles. Furthermore, neutrons allow for a backtracking of the emission point that is not affected by multiple scattering. Since neutrons can release a significant dose far away from the tumor region, a precise measurement of their flux, production energy and angle distributions is eagerly needed in order to improve the Treatment Planning Systems (TPS) software, so to predict not only the normal tissue toxicity in the target region but also the risk of late complications in the whole body. All the aforementioned issues underline the importance for an experimental effort devoted to the precise characterization of the neutron production gaining experimental access both to the emission point and production energy. The technical challenges posed by a neutron detector aiming for a high detection efficiency and good backtracking precision will be addressed within the MONDO (MOnitor for Neutron Dose in hadrOntherapy) project. The MONDO's main goal is to develop a tracking detector targeting fast and ultrafast secondary neutrons. The tracker is composed by a scintillating fiber matrix (4 × 4 × 8cm3). The full reconstruction of protons, produced in elastic interactions, will be used to measure energy and direction of the impinging neutron. The neutron tracker will measure the neutron production yields, as a function of production angle and energy, using different

  4. Biofuel blending reduces particle emissions from aircraft engines at cruise conditions

    Science.gov (United States)

    Moore, Richard H.; Thornhill, Kenneth L.; Weinzierl, Bernadett; Sauer, Daniel; D'Ascoli, Eugenio; Kim, Jin; Lichtenstern, Michael; Scheibe, Monika; Beaton, Brian; Beyersdorf, Andreas J.; Barrick, John; Bulzan, Dan; Corr, Chelsea A.; Crosbie, Ewan; Jurkat, Tina; Martin, Robert; Riddick, Dean; Shook, Michael; Slover, Gregory; Voigt, Christiane; White, Robert; Winstead, Edward; Yasky, Richard; Ziemba, Luke D.; Brown, Anthony; Schlager, Hans; Anderson, Bruce E.

    2017-03-01

    Aviation-related aerosol emissions contribute to the formation of contrail cirrus clouds that can alter upper tropospheric radiation and water budgets, and therefore climate. The magnitude of air-traffic-related aerosol-cloud interactions and the ways in which these interactions might change in the future remain uncertain. Modelling studies of the present and future effects of aviation on climate require detailed information about the number of aerosol particles emitted per kilogram of fuel burned and the microphysical properties of those aerosols that are relevant for cloud formation. However, previous observational data at cruise altitudes are sparse for engines burning conventional fuels, and no data have previously been reported for biofuel use in-flight. Here we report observations from research aircraft that sampled the exhaust of engines onboard a NASA DC-8 aircraft as they burned conventional Jet A fuel and a 50:50 (by volume) blend of Jet A fuel and a biofuel derived from Camelina oil. We show that, compared to using conventional fuels, biofuel blending reduces particle number and mass emissions immediately behind the aircraft by 50 to 70 per cent. Our observations quantify the impact of biofuel blending on aerosol emissions at cruise conditions and provide key microphysical parameters, which will be useful to assess the potential of biofuel use in aviation as a viable strategy to mitigate climate change.

  5. Delayed Proton Emission in the A=70 Region, a Strobe for Level Density and Particle Width

    CERN Multimedia

    2002-01-01

    The delayed particle emission, which is a characteristic signature of the most exotic nuclei decay, provides a wide variety of spectroscopic information among which level density, and gives in some cases access to selected microscopic structures. In regard to these two aspects the $\\beta^+$-EC delayed proton emission in the A=70 neutron deficient mass region is of special interest to be investigated. Indeed, in this area located close to the proton drip line and along the N=Z line, the delayed proton emission constitutes an access to level density in the Q$_{EC}$-S$_p$ window of the emitting nucleus. Moreover, the unbound states populated by the EC process are expected to exhibit lifetimes in the vicinity of the K electronic shell filling time ($\\tau\\!\\sim\\!2\\times10^{-16}$s) and so the particle widths can be reached via proton X-ray coincidence measurements (PXCT). From theoretical approaches strongly deformed low-spin proton unbound levels which may be populated in the T$_Z$ = 1/2 precursors decay are predi...

  6. Effects of Particle Filters and Accelerated Engine Replacement on Heavy-Duty Diesel Vehicle Emissions of Black Carbon, Nitrogen Oxides, and Ultrafine Particles

    Science.gov (United States)

    Kirchstetter, T.; Preble, C.; Dallmann, T. R.; DeMartini, S. J.; Tang, N. W.; Kreisberg, N. M.; Hering, S. V.; Harley, R. A.

    2013-12-01

    Diesel particle filters have become widely used in the United States since the introduction in 2007 of a more stringent exhaust particulate matter emission standard for new heavy-duty diesel vehicle engines. California has instituted additional regulations requiring retrofit or replacement of older in-use engines to accelerate emission reductions and air quality improvements. This presentation summarizes pollutant emission changes measured over several field campaigns at the Port of Oakland in the San Francisco Bay Area associated with diesel particulate filter use and accelerated modernization of the heavy-duty truck fleet. Pollutants in the exhaust plumes of hundreds of heavy-duty trucks en route to the Port were measured in 2009, 2010, 2011, and 2013. Ultrafine particle number, black carbon (BC), nitrogen oxides (NOx), and nitrogen dioxide (NO2) concentrations were measured at a frequency ≤ 1 Hz and normalized to measured carbon dioxide concentrations to quantify fuel-based emission factors (grams of pollutant emitted per kilogram of diesel consumed). The size distribution of particles in truck exhaust plumes was also measured at 1 Hz. In the two most recent campaigns, emissions were linked on a truck-by-truck basis to installed emission control equipment via the matching of transcribed license plates to a Port truck database. Accelerated replacement of older engines with newer engines and retrofit of trucks with diesel particle filters reduced fleet-average emissions of BC and NOx. Preliminary results from the two most recent field campaigns indicate that trucks without diesel particle filters emit 4 times more BC than filter-equipped trucks. Diesel particle filters increase emissions of NO2, however, and filter-equipped trucks have NO2/NOx ratios that are 4 to 7 times greater than trucks without filters. Preliminary findings related to particle size distribution indicate that (a) most trucks emitted particles characterized by a single mode of approximately

  7. Chemistry of new particle growth in mixed urban and biogenic emissions – insights from CARES

    Directory of Open Access Journals (Sweden)

    A. Setyan

    2014-01-01

    Full Text Available Regional new particle formation and growth events (NPE were observed on most days over the Sacramento and western Sierra Foothills area of California in June 2010 during the Carbonaceous Aerosols and Radiative Effect Study (CARES. Simultaneous particle measurements at both the T0 (Sacramento, urban site and the T1 (Cool, rural site located ~40 km northeast of Sacramento sites of CARES indicate that the NPE usually occurred in the morning with the appearance of an ultrafine mode centered at ~15 nm (in mobility diameter, Dm, measured by a scanning mobility particle sizer operating in the range 10–858 nm followed by the growth of this mode to ~50 nm in the afternoon. These events were generally associated with southwesterly winds bringing urban plumes from Sacramento to the T1 site. The growth rate was on average higher at T0 (7.1 ± 2.7 nm h−1 than at T1 (6.2 ± 2.5 nm h−1, likely due to stronger anthropogenic influences at T0. Using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, we investigated the evolution of the size-resolved chemical composition of new particles at T1. Our results indicate that the growth of new particles was driven primarily by the condensation of oxygenated organic species and, to a lesser extent, ammonium sulfate. New particles appear to be fully neutralized during growth, consistent with high NH3 concentration in the region. Nitrogen-containing organic ions (i.e., CHN+, CH4N+, C2H3N+, and C2H4N+ that are indicative of the presence of alkyl-amine species in submicrometer particles enhanced significantly during the NPE days, suggesting that amines might have played a role in these events. Our results also indicate that the bulk composition of the ultrafine mode organics during NPE was very similar to that of anthropogenically-influenced secondary organic aerosol (SOA observed in transported urban plumes. In addition, the concentrations of species representative of urban emissions (e.g., black

  8. Particle-Induced X-Ray Emission Analysis of Atmospheric Aerosols

    Science.gov (United States)

    Gleason, Colin; Harrington, Charles; Schuff, Katie; Battaglia, Maria; Moore, Robert; Turley, Colin; Vineyard, Michael; Labrake, Scott

    2010-11-01

    We are developing a research program in ion-beam analysis (IBA) of atmospheric aerosols at the Union College Ion-Beam Analysis Laboratory to study the transport, transformation, and effects of airborne pollution in Upstate New York. The simultaneous applications of the IBA techniques of particle-induced X-ray emission (PIXE), Rutherford back-scattering spectrometry (RBS), particle-induced gamma-ray emission (PIGE), and proton elastic scattering analysis (PESA) is a powerful tool for the study of airborne pollution because they are non-destructive and provide quantitative information on nearly all elements of the periodic table. PIXE is the main IBA technique because it is able to detect nearly all elements from Na to U with high sensitivities and low detection limits. The aerosol samples are collected with cascade impactors that allow for the study of particulate matter as a function of particle size and the samples are analyzed using proton beams with energies around 2 MeV from the Union College 1.1-MV Pelletron Accelerator. The emitted X-rays are measured using a silicon drift detector with a resolution of 136 eV. We will describe how the aerosol samples were collected, discuss the PIXE analysis, and present preliminary results.

  9. Laboratory testing of airborne brake wear particle emissions using a dynamometer system under urban city driving cycles

    Science.gov (United States)

    Hagino, Hiroyuki; Oyama, Motoaki; Sasaki, Sousuke

    2016-04-01

    To measure driving-distance-based mass emission factors for airborne brake wear particulate matter (PM; i.e., brake wear particles) related to the non-asbestos organic friction of brake assembly materials (pads and lining), and to characterize the components of brake wear particles, a brake wear dynamometer with a constant-volume sampling system was developed. Only a limited number of studies have investigated brake emissions under urban city driving cycles that correspond to the tailpipe emission test (i.e., JC08 or JE05 mode of Japanese tailpipe emission test cycles). The tests were performed using two passenger cars and one middle-class truck. The observed airborne brake wear particle emissions ranged from 0.04 to 1.4 mg/km/vehicle for PM10 (particles up to 10 μm (in size), and from 0.04 to 1.2 mg/km/vehicle for PM2.5. The proportion of brake wear debris emitted as airborne brake wear particles was 2-21% of the mass of wear. Oxygenated carbonaceous components were included in the airborne PM but not in the original friction material, which indicates that changes in carbon composition occurred during the abrasion process. Furthermore, this study identified the key tracers of brake wear particles (e.g., Fe, Cu, Ba, and Sb) at emission levels comparable to traffic-related atmospheric environments.

  10. Real-world traffic emission factors of gases and particles measured in a road tunnel in Stockholm, Sweden

    Science.gov (United States)

    Kristensson, Adam; Johansson, Christer; Westerholm, Roger; Swietlicki, Erik; Gidhagen, Lars; Wideqvist, Ulla; Vesely, Vaclav

    Measurements in a road tunnel in Stockholm, Sweden give the real-world traffic emission factors for a number of gaseous and particle pollutants. These include 49 different polycyclic aromatic hydrocarbons (PAH), CO, NO X, benzene, toluene, xylenes, aldehydes, elements and inorganic/organic carbon contained in particles, the sub-micrometer aerosol number size distribution, PM 2.5 and PM 10. The exhaust pipe emission factors are divided with the help of automated traffic counts into the two pollutant sources, the heavy-duty vehicles (HDV) and light-duty vehicles (LDV). The LDV fleet contains 95% petrol cars and the total fleet contains about 5% HDV. When data permitted, the emission factors were further calculated at different vehicle speeds. The current work shows that average CO, NO X and benzene emission factors amounted to 5.3, 1.4 and 0.017 g veh -1 km -1, respectively. Since the mid-90s CO and benzene decreased by about 15%, carbonyls by about a factor 2, whereas NO X did not change much. PAH emission factors were 2-15 times higher than found during dynamometer tests. Most particles are distributed around 20 nm diameter and the LDV fleet contributes to about 65% of both PM and particle number. In general, the gaseous emissions are higher in Sweden than in USA and Switzerland, foremost due to the lower fraction catalytic converters in Sweden. The PM and number emissions of particles are also slightly higher in the Swedish tunnel.

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

    NARCIS (Netherlands)

    Domínguez-Sáez, A.; Viana, M.; Barrios, C.C.; Rubio, J.R.; Amato, F.; Pujadas, M.; Querol, X.

    2012-01-01

    A novel on-board system was tested to characterize size-resolved particle number emission patterns under real-world driving conditions, running in a EURO4 diesel vehicle and in a typical urban circuit in Madrid (Spain). Emission profiles were determined as a function of driving conditions. Source ap

  12. Effects of bluff-body burner and coal particle size on NOx emissions and burnout

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, L.S.; Cheng, J.F.; Zeng, H.C. [Huazhong University of Science and Technology, Wuhan (China). National Coal Combustion Lab.

    1999-12-01

    Investigations on air staging have been carried out using various coals with different degrees of fineness and a variety of burners with a 92.9 kw h{sup -1} tunnel furnace burning pulverized coal. It has been observed that using the bluff-body burner can reduce both the unburned carbon in fly ash and NOx emissions in the case of air staging. The experimental results show that air-staging combustion has a more remarkable effect on NOx reduction for higher-volatile coal than for lower-volatile coal. The results also show that there is a strong influence of coal particle size on NOx emissions and unburned carbon in the fly ash in the case of air staging. 13 refs., 12 figs., 2 tabs.

  13. Application of Gauss's law space-charge limited emission model in iterative particle tracking method

    Science.gov (United States)

    Altsybeyev, V. V.; Ponomarev, V. A.

    2016-11-01

    The particle tracking method with a so-called gun iteration for modeling the space charge is discussed in the following paper. We suggest to apply the emission model based on the Gauss's law for the calculation of the space charge limited current density distribution using considered method. Based on the presented emission model we have developed a numerical algorithm for this calculations. This approach allows us to perform accurate and low time consumpting numerical simulations for different vacuum sources with the curved emitting surfaces and also in the presence of additional physical effects such as bipolar flows and backscattered electrons. The results of the simulations of the cylindrical diode and diode with elliptical emitter with the use of axysimmetric coordinates are presented. The high efficiency and accuracy of the suggested approach are confirmed by the obtained results and comparisons with the analytical solutions.

  14. Hydrothermal synthesis and infrared emissivity property of flower-like SnO2 particles

    Directory of Open Access Journals (Sweden)

    J. X. Tian

    2014-04-01

    Full Text Available The flower-like SnO2 particles are synthesized through a simple hydrothermal process. The microstructure, morphology and the infrared emissivity property of the as-prepared products are characterized by x-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscope (TEM, and infrared spectroradio meter (ISM respectively. The results show that the as-prepared SnO2 products are all indexed to tetragonal cassiterite phase of SnO2. The different molarity ratios of the OH− concentration to Sn4+ concentration ([OH−]:[Sn4+] and the polyacrylamide (PAM lead to the different morphological structures of SnO2, which indicates that both the [OH−]:[Sn4+] and the PAM play an important role in the morphological evolution respectively. The infrared emissivities of the as-prepared SnO2 products are discussed.

  15. The contribution of CHONS particles to the diffuse high Galactic latitude IR emission

    CERN Document Server

    Papoular, Renaud

    2014-01-01

    This work purports to model the far infrared gray-body emission in the spectra of high-Galactic-latitude clouds. Several carbonaceous laboratory materials are tested for their fitness as carriers of this modified-black-body emission which, according to data delivered by the Planck satellite, and others before, is best fit with temperature 17.9 K and spectral index beta=1.78. Some of these materials were discarded for insufficient emissivity, others for inadequate beta. By contrast, CHONS clusters (beta=1.4, T=19 K) combine nicely with magnesium silicate (beta=2, T=18.7 K) to give a spectrum which falls well within the observational error bars (total emission cross-section at 250 mum: 8.6 10^{-26} cm^{2} per H atom). Only 15 % of all Galactic carbon atoms are needed for this purpose. The CHONS particles that were considered and described have a disordered (amorphous) structure but include a sizable fraction of aromatic rings, although they are much less graphitized than a-C:H/HAC. They can be seen as one embod...

  16. Simultaneous collection of particles and acidic gases for tracing emission from coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Kitto, M.E.; Anderson, D.L.

    1986-04-01

    In this study, the authors employed the simultaneous collection of atmospheric particles and gases followed by multielement analysis as an approach for the determination of source-receptor relationships. A number of particulate tracer elements have previously been linked to sources (e.g., V to identify oil-fired power plant emissions, Na for marine aerosols, and Pb for motor vehicle contribution). Receptor methods commonly used to assess the interregional impact of such emissions include chemical mass balances (CMBs) and factor analysis (FA), the latter often including wind trajectories. With CMBs, source-strengths are determined from the relative concentrations of ''marker elements'' measured at emission sources. One usually applies FA to the data set to identify groups of elements which vary similarly. The source composition patterns are not necessary, as the elemental concentrations in each sample are normalized to the mean value of the element. In this study, the authors try to extend tracer techniques for coal-burning utility emissions to include gas-phase elements, and to relate receptor measurements to the hybrid receptor model.

  17. Ambient exposure to coarse and fine particle emissions from building demolition

    Science.gov (United States)

    Azarmi, Farhad; Kumar, Prashant

    2016-07-01

    Demolition of buildings produce large quantities of particulate matter (PM) that could be inhaled by on-site workers and people living in the neighbourhood, but studies assessing ambient exposure at the real-world demolition sites are limited. We measured concentrations of PM10 (≤10 μm), PM2.5 (≤2.5 μm) and PM1 (≤1 μm) along with local meteorology for 54 working hours over the demolition period. The measurements were carried out at (i) a fixed-site in the downwind of demolished building, (ii) around the site during demolition operation through mobile monitoring, (iii) different distances away from the demolition site through sequential monitoring, and (iv) inside an excavator vehicle cabin and on-site temporary office for engineers. Position of the PM instrument was continuously recorded using a Global Positioning System on a second basis during mobile measurements. Fraction of coarse particles (PM2.5-10) contributed 89 (with mean particle mass concentration, PMC ≈ 133 ± 17 μg m-3), 83 (100 ± 29 μg m-3), and 70% (59 ± 12 μg m-3) of total PMC during the fixed-site, mobile monitoring and sequential measurements, respectively, compared with only 50% (mean 12 ± 6 μg m-3) during the background measurements. The corresponding values for fine particles (PM2.5) were 11, 17 and 30% compared with 50% during background, showing a much greater release of coarse particles during demolition. The openair package in R and map source software (ArcGIS) were used to assess spatial variation of PMCs in downwind and upwind of the demolition site. A modified box model was developed to determine the emission factors, which were 210, 73 and 24 μg m-2 s-1 for PM10, PM2.5 and PM1, respectively. The average respiratory deposited doses to coarse (and fine) particles inside the excavator cabin and on-site temporary office increased by 57- (and 5-) and 13- (and 2-) times compared with the local background level, respectively. The monitoring stations in downwind direction

  18. Carbon Nanotube Emissions from Arc Discharge Production: Classification of Particle Types with Electron Microscopy and Comparison with Direct Reading Techniques.

    Science.gov (United States)

    Ludvigsson, Linus; Isaxon, Christina; Nilsson, Patrik T; Tinnerberg, Hakan; Messing, Maria E; Rissler, Jenny; Skaug, Vidar; Gudmundsson, Anders; Bohgard, Mats; Hedmer, Maria; Pagels, Joakim

    2016-05-01

    An increased production and use of carbon nanotubes (CNTs) is occurring worldwide. In parallel, a growing concern is emerging on the adverse effects the unintentional inhalation of CNTs can have on humans. There is currently a debate regarding which exposure metrics and measurement strategies are the most relevant to investigate workplace exposures to CNTs. This study investigated workplace CNT emissions using a combination of time-integrated filter sampling for scanning electron microscopy (SEM) and direct reading aerosol instruments (DRIs). Field measurements were performed during small-scale manufacturing of multiwalled carbon nanotubes using the arc discharge technique. Measurements with highly time- and size-resolved DRI techniques were carried out both in the emission and background (far-field) zones. Novel classifications and counting criteria were set up for the SEM method. Three classes of CNT-containing particles were defined: type 1: particles with aspect ratio length:width >3:1 (fibrous particles); type 2: particles without fibre characteristics but with high CNT content; and type 3: particles with visible embedded CNTs. Offline sampling using SEM showed emissions of CNT-containing particles in 5 out of 11 work tasks. The particles were classified into the three classes, of which type 1, fibrous CNT particles contributed 37%. The concentration of all CNT-containing particles and the occurrence of the particle classes varied strongly between work tasks. Based on the emission measurements, it was assessed that more than 85% of the exposure originated from open handling of CNT powder during the Sieving, mechanical work-up, and packaging work task. The DRI measurements provided complementary information, which combined with SEM provided information on: (i) the background adjusted emission concentration from each work task in different particle size ranges, (ii) identification of the key procedures in each work task that lead to emission peaks, (iii

  19. Simulating Emission and Chemical Evolution of Coarse Sea-Salt Particles in the Community Multiscale Air Quality (CMAQ) Model

    Science.gov (United States)

    Chemical processing of sea-salt particles in coastal environments significantly impacts concentrations of particle components and gas-phase species and has implications for human exposure to particulate matter and nitrogen deposition to sensitive ecosystems. Emission of sea-sal...

  20. Airborne particle emission of a commercial 3D printer: the effect of filament material and printing temperature.

    Science.gov (United States)

    Stabile, L; Scungio, M; Buonanno, G; Arpino, F; Ficco, G

    2017-03-01

    The knowledge of exposure to the airborne particle emitted from three-dimensional (3D) printing activities is becoming a crucial issue due to the relevant spreading of such devices in recent years. To this end, a low-cost desktop 3D printer based on fused deposition modeling (FDM) principle was used. Particle number, alveolar-deposited surface area, and mass concentrations were measured continuously during printing processes to evaluate particle emission rates (ERs) and factors. Particle number distribution measurements were also performed to characterize the size of the emitted particles. Ten different materials and different extrusion temperatures were considered in the survey. Results showed that all the investigated materials emit particles in the ultrafine range (with a mode in the 10-30-nm range), whereas no emission of super-micron particles was detected for all the materials under investigation. The emission was affected strongly by the extrusion temperature. In fact, the ERs increase as the extrusion temperature increases. Emission rates up to 1×10(12)  particles min(-1) were calculated. Such high ERs were estimated to cause large alveolar surface area dose in workers when 3D activities run. In fact, a 40-min-long 3D printing was found to cause doses up to 200 mm(2) . © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. IN VIVO EVIDENCE OF FREE RADICAL FORMATION IN THE RAT LUNG AFTER EXPOSURE TO AN EMISSION SOURCE AIR POLLUTION PARTICLE

    Science.gov (United States)

    Exposure to air pollution particles can be associated with increased human morbidity and mortality. The mechanism(s) of lung injury remains unknown. We tested the hypothesis that lung exposure to oil fly ash (an emission source air pollution particle) causes in vivo free radical ...

  2. Multiplicity of pre-scission charged particle emission by a statistical model

    Energy Technology Data Exchange (ETDEWEB)

    Matsuse, Takehiro [Shinshu Univ., Ueda, Nagano (Japan). Faculty of Textile Science and Technology

    1996-03-01

    With introducing the limitation (E{sub cut-off}) not to excite all statistically permitted scission parts in the phase integral at the scission point, we try to reproduce the multiplicity of pre-scission charged particle emission of 86 Kr (E{sub lab}=890 MeV)+{sup 27}Al by the cascade calculation of the extended Hauser-Feshbach method (EHM). The physical image is explained from a point of view of the life time for the statistical model of the compound nuclei. When E{sub cut-off} parameter is bout 80 MeV, the cross section of scission and the loss of pre-scission charged particle seemed to be reproduced. The average pre-scission time is about 1.7 x 10{sup -20} sec. The essential problem of the life time of compound nuclei is explained. (S.Y.)

  3. Development of a Reference Database for Particle-Induced Gamma-ray Emission spectroscopy

    Science.gov (United States)

    Dimitriou, P.; Becker, H.-W.; Bogdanović-Radović, I.; Chiari, M.; Goncharov, A.; Jesus, A. P.; Kakuee, O.; Kiss, A. Z.; Lagoyannis, A.; Räisänen, J.; Strivay, D.; Zucchiatti, A.

    2016-03-01

    Particle-Induced Gamma-ray Emission (PIGE) is a powerful analytical technique that exploits the interactions of rapid charged particles with nuclei located near a sample surface to determine the composition and structure of the surface regions of solids by measurement of characteristic prompt γ rays. The potential for depth profiling of this technique has long been recognized, however, the implementation has been limited owing to insufficient knowledge of the physical data and lack of suitable user-friendly computer codes for the applications. Although a considerable body of published data exists in the nuclear physics literature for nuclear reaction cross sections with γ rays in the exit channel, there is no up-to-date, comprehensive compilation specifically dedicated to IBA applications. A number of PIGE cross-section data had already been uploaded to the Ion Beam Analysis Nuclear Data Library (IBANDL)

  4. Reduction of fine particle emissions from wood combustion with optimized condensing heat exchangers.

    Science.gov (United States)

    Gröhn, Arto; Suonmaa, Valtteri; Auvinen, Ari; Lehtinen, Kari E J; Jokiniemi, Jorma

    2009-08-15

    In this study, we designed and built a condensing heat exchanger capable of simultaneous fine particle emission reduction and waste heat recovery. The deposition mechanisms inside the heat exchanger prototype were maximized using a computer model which was later compared to actual measurements. The main deposition mechanisms were diffusio- and thermophoresis which have previously been examined in similar conditions only separately. The obtained removal efficiency in the experiments was measured in the total number concentration and ranged between 26 and 40% for the given pellet stove and the heat exchanger. Size distributions and number concentrations were measured with a TSI Fast mobility particle sizer (FMPS). The computer model predicts that there exists a specific upper limit for thermo- and diffusiophoretic deposition for each temperature and water vapor concentration in the flue gas.

  5. {alpha}-particle emission probabilities in the decay of {sup 235}U

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Torano, Eduardo [Laboratorio de Metrologia de Radiaciones Ionizantes, CIEMAT, Madrid (Spain)]. E-mail: E.Garciatorano@ciemat.es; Teresa Crespo, M. [Laboratorio de Metrologia de Radiaciones Ionizantes, CIEMAT, Madrid (Spain); Roteta, Miguel [Laboratorio de Metrologia de Radiaciones Ionizantes, CIEMAT, Madrid (Spain); Sibbens, Goedele [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel (Belgium); Pomme, Stefaan [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel (Belgium); Martin Sanchez, Alejandro [Departamento de Fisica, Universidad de Extremadura, Badajoz (Spain); Pilar Rubio Montero, M. [Departamento de Fisica, Universidad de Extremadura, Badajoz (Spain); Woods, Simon [Radioactivity Metrology Group, National Physical Laboratory, Teddington, Middlesex (United Kingdom); Pearce, Andy [Radioactivity Metrology Group, National Physical Laboratory, Teddington, Middlesex (United Kingdom)

    2005-09-21

    {sup 235}U decays by {alpha}-particle emission to {sup 231}Th. The decay scheme of this nuclide is very complex, with more than 20 alpha branches. Recommended values for P {sub {alpha}} of this nuclide are based on measurements carried out in 1975. This work presents the results of new measurements made with Si detectors and sources of enriched uranium in the frame of the EUROMET 591 cooperation project. The use of improved measurement techniques and numerical analysis of spectra allowed a new set of P {sub {alpha}} values for 13 lines with improved uncertainties to be obtained.

  6. Constraints on uncertainties and their application to the emission probabilities of alpha-particles

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, A.M. (Dept. de Fisica, Univ. de Extremadura, Badajoz (Spain)); Tome, F.V. (Dept. de Fisica, Univ. de Extremadura, Badajoz (Spain)); Diaz Bejarano, J. (Dept. de Fisica, Univ. de Extremadura, Badajoz (Spain))

    1994-03-08

    It often happens that the mean values of certain quantities are subject to constraints as, for example, when a sum is known exactly although the individual contributions have been measured independently and their corresponding uncertainties assigned. In this paper, the influence of a constraint on the final expression of the results is studied in detail, and is illustrated in the alpha-particle emission probabilities for several nuclides from nuclear data tables. A simple rule emerges: If the mean values must add to 100% and if one of the variances is greater than half the sum of all the variances, then the precision in the expression of the results can be improved. (orig.)

  7. Support vector machine to predict diesel engine performance and emission parameters fueled with nano-particles additive to diesel fuel

    Science.gov (United States)

    Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

    2015-12-01

    This paper studies the use of adaptive Support Vector Machine (SVM) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For SVM modelling, different values for radial basis function (RBF) kernel width and penalty parameters (C) were considered and the optimum values were then found. The results demonstrate that SVM is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

  8. Search for invisible particles produced in association with single-top-quarks in proton-proton collisions at $\\sqrt{s}$ = 8 TeV with the ATLAS detector

    CERN Document Server

    Aad, Georges; Abdallah, Jalal; Abdel Khalek, Samah; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Abreu, Ricardo; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Agatonovic-Jovin, Tatjana; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Ahlen, Steven; Ahmadov, Faig; Aielli, Giulio; Akerstedt, Henrik; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alberghi, Gian Luigi; Albert, Justin; Albrand, Solveig; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Alimonti, Gianluca; Alio, Lion; Alison, John; Allbrooke, Benedict; Allison, Lee John; Allport, Phillip; Aloisio, Alberto; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amaral Coutinho, Yara; Amelung, Christoph; Amidei, Dante; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amoroso, Simone; Amram, Nir; Amundsen, Glenn; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Anduaga, Xabier; Angelidakis, Stylianos; Angelozzi, Ivan; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Araque, Juan Pedro; Arce, Ayana; Arduh, Francisco Anuar; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnold, Hannah; Arratia, Miguel; Arslan, Ozan; Artamonov, Andrei; Artoni, Giacomo; Asai, Shoji; Asbah, Nedaa; Ashkenazi, Adi; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astalos, Robert; Atkinson, Markus; Atlay, Naim Bora; Auerbach, Benjamin; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Axen, Bradley; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baas, Alessandra; Bacci, Cesare; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Badescu, Elisabeta; Bagiacchi, Paolo; Bagnaia, Paolo; Bai, Yu; Bain, Travis; Baines, John; Baker, Oliver Keith; Balek, Petr; Balli, Fabrice; Banas, Elzbieta; Banerjee, Swagato; Bannoura, Arwa A E; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnes, Sarah Louise; Barnett, Bruce; Barnett, Michael; Barnovska, Zuzana; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Bartoldus, Rainer; Barton, Adam Edward; Bartos, Pavol; Bartsch, Valeria; Bassalat, Ahmed; Basye, Austin; Bates, Richard; Batista, Santiago Juan; Batley, Richard; Battaglia, Marco; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beacham, James Baker; Beattie, Michael David; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becot, Cyril; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Beermann, Thomas; Begel, Michael; Behr, Katharina; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellerive, Alain; Bellomo, Massimiliano; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Bensinger, James; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Beringer, Jürg; Bernard, Clare; Bernard, Nathan Rogers; Bernius, Catrin; Bernlochner, Florian Urs; Berry, Tracey; Berta, Peter; Bertella, Claudia; Bertoli, Gabriele; Bertolucci, Federico; Bertsche, Carolyn; Bertsche, David; Besana, Maria Ilaria; Besjes, Geert-Jan; Bessidskaia, Olga; Bessner, Martin Florian; Besson, Nathalie; Betancourt, Christopher; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biglietti, Michela; Bilbao De Mendizabal, Javier; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Black, Curtis

    2015-01-01

    A search for the production of single-top-quarks in association with missing energy is performed in proton--proton collisions at a centre-of-mass energy of $\\sqrt{s}$ = 8 TeV with the ATLAS experiment at the Large Hadron Collider using data collected in 2012, corresponding to an integrated luminosity of 20.3 fb$^{-1}$. In this search, the $W$ boson from the top quark is required to decay into an electron or a muon and a neutrino. No deviation from the Standard Model prediction is observed, and upper limits are set on the production cross-section for resonant and non-resonant production of an invisible exotic state in association with a right-handed top quark. In the case of resonant production, for a spin-$0$ resonance with a mass of 500 GeV, an effective coupling strength above 0.15 is excluded at 95% confidence level for the top quark and an invisible spin-$1/2$ state with mass between 0 GeV and 100 GeV. In the case of non-resonant production, an effective coupling strength above 0.2 is excluded at 95% conf...

  9. Emissions of Black Carbon Particles from Biomass Burning and Their Physical and Chemical Properties

    Science.gov (United States)

    Kondo, Y.; Sahu, L.; Moteki, N.; Takegawa, N.; Zhao, Y.; Vay, S. A.; Diskin, G. S.; Wisthaler, A.; Huey, L. G.; Jimenez, J. L.

    2009-12-01

    Large amounts of aerosol, including black carbon (BC), are emitted from biomass burning. It is therefore important to understand the chemical composition, rate of emissions, and mixing state of aerosols generated by this combustion process to estimate the impacts of aerosols on climate. Thus far, these physical and chemical quantities have been compiled by combining the data from laboratory and field experiments, but the data from the Arctic region are still very limited. These parameters were measured by an SP2 instrument based on the laser-induced incandescence technique on board the NASA DC-8 during the ARCTAS campaign. Aircraft sampling was made in plumes emitted by wildfires in Canada and the USA, and in those transported over long distances from Russia. First, we extract biomass burning plumes using CH3CN and SO2 data. Then, we derived the slopes of the CO-CO2-CH3CN-aerosol correlations for each burning plume. Based on this, we derive the average CO/CO2, CH3CN/CO2, BC/CO2, and BC/CO ratios together with their variability in the plumes strongly influenced by forest fires over Siberia, California, and Canada. A similar analysis is made for light-scattering particles. Using these relationships, the transport efficiencies of BC particles from the boundary layer to the free troposphere are also estimated. It is found that the BC particles were thickly coated upon emission. From comparison with AMS measurements, the coating materials are found to be mainly composed of organic compounds. This indicates the importance of the enhanced light absorption by BC particles emitted by biomass burning.

  10. Pre-Equilibrium Alpha-Particle Emission as a Probe to Explore Alpha Clustering in Nuclei

    Science.gov (United States)

    Kravchuk, V. L.; Fotina, O. V.; Gramegna, F.; Bruno, M.; D'Agostino, M.; Sambi, S.; Barlini, S.; Casini, G.

    Experimental data of the double-differential spectra of light particles emitted at pre-equilibrium stage of nuclear processes were obtained at Laboratori Nazionali di Legnaro for the heavy-ion reactions 130 and 250 MeV 16O + 116Sn. Light charged particles were measured in coincidence with evaporation residues in order to avoid unwanted competing mechanisms. The experimental data were collected in a wide angular range from 29 to 82 degrees in the laboratory system. Theoretical model was developed in order to describe simultaneously evaporative and pre-equilibrium emission of the light particles in heavy-ion reactions. Griffin exciton model was used for the description of the pre-equilibrium stage of the compound nucleus formation, while the equilibrium evaporation processes were analyzed in the framework of the statistical theory of heavy-ion reactions. Experimental data were compared with the results of the model calculations and new approach was suggested to take into account alpha cluster formation in the projectile nucleus by measuring and analyzing pre-equilibrium alpha-particle spectra.

  11. Search for an invisibly-decaying Higgs boson at LEP

    CERN Document Server

    Achard, P; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Anderhub, H; Andreev, V P; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, G; Baksay, L; Baldew, S V; Banerjee, S; Barczyk, A; Barillère, 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; Böhm, A; Boldizsar, L; Borgia, B; Bottai, S; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; 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-Llatas, M; Chang, Y H; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; 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; Déglon, P L; Debreczeni, J; Degré, A; Dehmelt, K; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Dionisi, C; Dittmar, M; Doria, A; Dova, M T; Duchesneau, D; Duda, M; Echenard, B; Eline, A; El-Hage, A; El-Mamouni, H; Engler, A; Eppling, F J; Extermann, P; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, M; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, F; Fisher, P H; Fisher, W; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gentile, S; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Hofer, H; Hohlmann, M; Holzner, G; Hou, S R; Hu, Y; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kaur, M; Kienzle-Focacci, M N; Kim, J K; Kirkby, Jasper; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Koutsenko, V F; Kraber, M; Krämer, R W; Krüger, A; Kunin, A; Ladrón 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, M; Levchenko, P M; Li, C; Likhoded, S; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Luci, C; Luminari, L; Lustermann, W; Ma Wen Gan; Malgeri, L; Malinin, A; Maña, C; 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; Nisati, A; Novák, T; Nowak, H; Ofierzynski, R A; Organtini, G; Pal, I; Palomares, C; Paolucci, P; Paramatti, R; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pioppi, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Pothier, J; Prokofev, D; Prokofiev, D O; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Razis, P; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Roe, B P; Romero, L; Rosca, A; Rosemann, C; Rosenbleck, C; Rosier-Lees, S; Roth, S; Rubio, J A; Ruggiero, G; Rykaczewski, H; Sakharov, A; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Schäfer, C; Shchegelskii, V; Schopper, Herwig Franz; Schotanus, D J; Sciacca, C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A; Son, D; Souga, C; Spillantini, P; Steuer, M; Stickland, D P; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S; Suter, H; Swain, J D; Szillási, Z; Tang, X W; Tarjan, P; Tauscher, L; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Ulbricht, J; Valente, E; Van de Walle, R T; Vásquez, R; Veszpremi, V; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Wadhwa, M; Wang, Q; Wang, X L; Wang, Z M; Weber, M; 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; Zimmermann, B; Zöller, M

    2005-01-01

    A search for a Higgs boson produced in e^+e^- collisions in association with a Z boson and decaying into invisible particles is performed. Data collected at LEP with the L3 detector at centre-of-mass energies from 189 GeV to 209 GeV are used, corresponding to an integrated luminosity of 0.63/fb. Events with hadrons, electrons or muons with visible masses compatible with a Z boson and missing energy and momentum are selected. They are consistent with the Standard Model expectations. A lower limit of 112.3 GeV is set at 95% confidence level on the mass of the invisibly-decaying Higgs boson in the hypothesis that its production cross section equals that of the Standard Model Higgs boson. Relaxing this hypothesis, upper limits on the production cross section are derived.

  12. Search for invisible decay modes of the Higgs boson with the ATLAS detector

    CERN Document Server

    Trovatelli, Monica; The ATLAS collaboration

    2016-01-01

    The Higgs boson provides a unique way to probe the production of Dark Matter particles in the proton-proton collisions at the Large Hadron Collider, through searches for its decay into invisible particles. With the data sample collected at the centre-of-mass energy of 8 TeV the ATLAS Collaboration has performed searches in a number of production modes of the Higgs boson. The results are compatible with the Standard Model expectations and they have been used to set upper limits on the branching ratio for the Higgs decay into invisible particles. A first result obtained with data collected at the new energy regime of 13 TeV in the $ZH,\\,Z\\rightarrow \\ell\\ell$ $H\\rightarrow$ \\textit{invisible} channel has also been presented.

  13. Fireplace and woodstove fine particle emissions from combustion of western Mediterranean wood types

    Science.gov (United States)

    Alves, Célia; Gonçalves, Cátia; Fernandes, Ana Patrícia; Tarelho, Luís; Pio, Casimiro

    2011-08-01

    Wood from seven species of trees grown in the Portuguese forest ( Pinus pinaster, Eucalyptus globulus, Quercus suber, Acacia longifolia, Quercus faginea, Olea europea and Quercus ilex rotundifolia), and briquettes produced from forest biomass waste were burned in a fireplace and in a woodstove to determine the chemical composition of fine particle (PM 2.5) emissions. Samples were analysed for organic and elemental carbon (OC/EC), water soluble ions (Na +, NH 4+, K +, Mg 2+, Ca 2+, Cl -, NO 3- and SO 42-) and 67 elements. The PM 2.5 emission factors (g kg - 1 fuel burned, dry basis) were in the ranges 9.9-20.2 and 4.2-16.3, respectively, for the fireplace and the woodstove. Organic carbon contributed to about 50% of the fine particle mass in the emissions from every wood species studied in both burning appliances. The carbonaceous component of PM 2.5 was dominated by organic carbon, accounting for more than 85% of the total carbon (TC): OC/TC ranged from 0.85 to 0.96 (avg. 0.92) for the fireplace and from 0.86 to 0.97 (avg. 0.93) for the woodstove. The water-soluble ions accounted for 0.64 to 11.3% of the PM 2.5 mass emitted from the fireplace, whereas mass fractions between 0.53 and 13.6% were obtained for the woodstove. The golden wattle wood smoke showed a much higher ionic content than the emissions from the other wood types. Trace elements represented 0.4 to 2.5% and 0.2 to 2.2% of the PM 2.5 mass emitted, respectively, from the fireplace and the woodstove, which corresponded to average total emissions of 132 ± 77.3 mg kg - 1 and 93.4 ± 60.8 mg kg - 1 of wood burned. Among these, K, Pb, Al, Mn and Sr were present in all samples. From the emission profiles of the individual experiments, composite wood combustion profiles are suggested with the aid of a cluster analysis.

  14. Emissions from carpet combustion in a pilot-scale rotary kiln: comparison with coal and particle-board combustion.

    Science.gov (United States)

    Konopa, Stephanie Lucero; Mulholland, James A; Realff, Matthew J; Lemieux, Paul M

    2008-08-01

    The use of post-consumer carpet as a potential fuel substitute in cement kilns and other high-temperature processes is being considered to address the problem of huge volumes of carpet waste and the opportunity of waste-to-energy recovery. Carpet represents a high volume waste stream, provides high energy value, and contains other recoverable materials for the production of cement. This research studied the emission characteristics of burning 0.46-kg charges of chopped nylon carpet squares, pulverized coal, and particle-board pellets in a pilot-scale natural gas-fired rotary kiln. Carpet was tested with different amounts of water added. Emissions of oxygen, carbon dioxide, nitric oxide (NO), sulfur dioxide (SO2), carbon monoxide (CO), and total hydrocarbons and temperatures were continuously monitored. It was found that carpet burned faster and more completely than coal and particle board, with a rapid volatile release that resulted in large and variable transient emission peaks. NO emissions from carpet combustion ranged from 0.06 to 0.15 g/MJ and were inversely related to CO emissions. Carpet combustion yielded higher NO emissions than coal and particle-board combustion, consistent with its higher nitrogen content. SO2 emissions were highest for coal combustion, consistent with its higher sulfur content than carpet or particle board. Adding water to carpet slowed its burn time and reduced variability in the emission transients, reducing the CO peak but increasing NO emissions. Results of this study indicate that carpet waste can be used as an effective alternative fuel, with the caveats that it might be necessary to wet carpet or chop it finely to avoid excessive transient puff emissions due to its high volatility compared with other solid fuels, and that controlled mixing of combustion air might be used to control NO emissions from nylon carpet.

  15. Pre-equilibrium {\\alpha}-particle emission as a probe to study {\\alpha}-clustering in nuclei

    CERN Document Server

    Fotina, O V; Eremenko, D O; Platonov, S Yu; Yuminov, O A; Kravchuk, V L; Gramegna, F; Marchi, T; Cinausero, M; D'Agostino, M; Bruno, M; Baiocco, G; Morelli, L; Degerlier, M; Casini, G; Barlini, S; Valdrè, S; Piantelli, S; Pasquali, G; Bracco, A; Camera, F; Wieland, O; Benzoni, G; Blasi, N; Giaz, A; Corsi, A

    2013-01-01

    A theoretical approach was developed to describe secondary particle emission in heavy ion collisions, with special regards to pre-equilibrium {\\alpha}-particle production. Griffin's model of non-equilibrium processes is used to account for the first stage of the compound system formation, while a Monte Carlo statistical approach was used to describe the further decay from a hot source at thermal equilibrium. The probabilities of neutron, proton and {\\alpha}-particle emission have been evaluated for both the equilibrium and pre-equilibrium stages of the process. Fission and {\\gamma}-ray emission competition were also considered after equilibration. Effects due the possible cluster structure of the projectile which has been excited during the collisions have been experimentally evidenced studying the double differential cross sections of p and {\\alpha}-particles emitted in the E=250MeV 16O +116Sn reaction. Calculations within the present model with different clusterization probabilities have been compared to th...

  16. Transition-Edge Sensors for Particle Induced X-ray Emission Measurements

    CERN Document Server

    Palosaari, M R J; Julin, J; Laitinen, M; Napari, M; Sajavaara, T; Doriese, W B; Fowler, J; Reintsema, C; Swetz, D; Schmidt, D; Ullom, J; Maasilta, I J

    2013-01-01

    In this paper we present a new measurement setup, where a transitionedge sensor detector array is used to detect X-rays in particle induced X-ray emission measurements with a 2 MeV proton beam. Transition-edge sensors offer orders of magnitude improvement in energy resolution compared to conventional silicon or germanium detectors, making it possible to recognize spectral lines in materials analysis that have previously been impossible to resolve, and to get chemical information from the elements. Our sensors are cooled to the operation temperature (65 mK) with a cryogen-free adiabatic demagnetization refrigerator, which houses a specially designed X-ray snout that has a vacuum tight window to couple in the radiation. For the best pixel, the measured instrumental energy resolution was 3.06 eV full width at half maximum at 5.9 keV.We discuss the current status of the project, benefits of transition-edge sensors when used in particle induced X-ray emission spectroscopy, and the results from the first measuremen...

  17. Laser damage studies of ZnS via neutral Zn particle emission

    Science.gov (United States)

    Arlinghaus, H. F.; Calaway, W. F.; Young, C. E.; Pellin, M. J.; Gruen, D. M.; Chase, L. L.

    1989-10-01

    Emission of neutral atoms from ZnS surfaces due to laser irradiation has been observed at power densities two orders of magnitude below the single pulse damage threshold of the material. We have measured the velocity distribution and absolute yield of neutral Zn atoms generated by exposure of ZnS single crystals to XeCl excimer laser irradiation (308 nm) using time-of-flight and high-resolution two-photon laser-induced fluorescence spectroscpy. The distributions are in agreement with Maxwell-Boltzmann distributions. The characteristic temperature increases from 2000 to 9000 K as the fluences are raised from 17 to 80 mJ/cm2, respectively. The absolute Zn yield also increased from 108 to 1012 atoms per laser pulse as the laser fluence is increased. The insults suggest formation of a plasma that interacts with the surface and leads to catastrophic failure. For consecutive laser shots at constant lasers fluences, a nearly exponential increase in the Zn particle density is observed, yet visible damage did not occur until 150,000 laser shots. Our results show that neutral particle emission is of considerable importance in the identification of fundamental damage mechanisms and that microscopic damage occurs far below the single-pulse damage threshold.

  18. Modeling particle-induced electron emission in a simplified plasma Test Cell

    Energy Technology Data Exchange (ETDEWEB)

    Giuliano, Paul N.; Boyd, Iain D. [Department of Aerospace Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2013-03-21

    Particle-induced electron emission (PIE) is modeled in a simplified, well-characterized plasma Test Cell operated at UCLA. In order for PIE to be a useful model in this environment, its governing equations are first reduced to lower-order models which can be implemented in a direct simulation Monte Carlo and Particle-in-Cell framework. These reduced-order models are described in full and presented as semi-empirical models. The models are implemented to analyze the interaction of low- and high-energy ({approx}1-2 keV) xenon ions and atoms with the stainless steel electrodes of the Test Cell in order to gain insight into the emission and transport of secondary electrons. Furthermore, there is a lack of data for xenon-stainless steel atom- and ion-surface interactions for similar environments. Using experimental data as a reference, both total yields and emitted electron energy distribution functions can be deduced by observing sensitivities of current collection results to these numerical models and their parameters.

  19. Double differential light charged particle emission cross sections for some structural fusion materials

    Science.gov (United States)

    Sarpün, Ismail Hakki; n, Abdullah Aydı; Tel, Eyyup

    2017-09-01

    In fusion reactors, neutron induced radioactivity strongly depends on the irradiated material. So, a proper selection of structural materials will have been limited the radioactive inventory in a fusion reactor. First-wall and blanket components have high radioactivity concentration due to being the most flux-exposed structures. The main objective of fusion structural material research is the development and selection of materials for reactor components with good thermo-mechanical and physical properties, coupled with low-activation characteristics. Double differential light charged particle emission cross section, which is a fundamental data to determine nuclear heating and material damages in structural fusion material research, for some elements target nuclei have been calculated by the TALYS 1.8 nuclear reaction code at 14-15 MeV neutron incident energy and compared with available experimental data in EXFOR library. Direct, compound and pre-equilibrium reaction contribution have been theoretically calculated and dominant contribution have been determined for each emission of proton, deuteron and alpha particle.

  20. Habitantes invisibles de la Escuela

    OpenAIRE

    Lobato Carvajal, José Ángel; Camacho Santiago, Carlota; Touilae Mezguildi, Hassan

    2015-01-01

    Se trata de una Conferencia en formato Mesa Redonda a la que vienen 3 ó 4 personas que representan a colectivos poco dominantes en el sistema escolar (personas con discapacidad, en situación de inmigración, de etnia gitana, de ámbitos rurales, mujeres, alumnado con enfermedad crónica, etc.). Dos de los nombres que ha tenido esta mesa son: "Habitantes invisibles de la escuela" o  "¿Es ésta, también, mi escuela?". A los ponentes que vienen se les pide que cuenten las cosas más importantes d...

  1. Development of a composite line source emission model for traffic interrupted microenvironments and its application in particle number emissions at a bus station

    Science.gov (United States)

    Wang, Lina; Jayaratne, Rohan; Heuff, Darlene; Morawska, Lidia

    A composite line source emission (CLSE) model was developed to specifically quantify exposure levels and describe the spatial variability of vehicle emissions in traffic interrupted microenvironments. This model took into account the complexity of vehicle movements in the queue, as well as different emission rates relevant to various driving conditions (cruise, decelerate, idle and accelerate), and it utilised multi-representative segments to capture the accurate emission distribution for real vehicle flow. Hence, this model was able to quickly quantify the time spent in each segment within the considered zone, as well as the composition and position of the requisite segments based on the vehicle fleet information, which not only helped to quantify the enhanced emissions at critical locations, but it also helped to define the emission source distribution of the disrupted steady flow for further dispersion modelling. The model then was applied to estimate particle number emissions at a bi-directional bus station used by diesel and compressed natural gas fuelled buses. It was found that the acceleration distance was of critical importance when estimating particle number emission, since the highest emissions occurred in sections where most of the buses were accelerating and no significant increases were observed at locations where they idled. It was also shown that emissions at the front end of the platform were 43 times greater than at the rear of the platform. Although the CLSE model is intended to be applied in traffic management and transport analysis systems for the evaluation of exposure, as well as the simulation of vehicle emissions in traffic interrupted microenvironments, the bus station model can also be used for the input of initial source definitions in future dispersion models.

  2. New particle formation from the oxidation of direct emissions of pine seedlings

    Directory of Open Access Journals (Sweden)

    L. Q. Hao

    2009-03-01

    Full Text Available Measurements of particle formation following the gas phase oxidation of volatile organic compounds (VOCs emitted by Scots pine (Pinus sylvestris L. seedlings are reported. Particle nucleation and condensational growth both from ozone (O3 and hydroxyl radical (OH initiated oxidation of pine emissions (about 20–120 ppb were investigated in a~smog chamber. During experiments, tetramethylethylene (TME and 2-butanol were added to control the concentrations of O3 and OH. Particle nucleation and condensational growth rates were interpreted with a chemical kinetics model. Scots pine emissions mainly included α-pinene, β-pinene, Δ3-carene, limonene, myrcene, β-phellandrene and isoprene, composing more than 95% of total emissions. Modeled OH concentration in the O3+OH induced experiments was at a level of ~106 molecular cm−3. Our results demonstrate that OH-initiated oxidation of VOCs plays an important role in the nucleation process during the initial new particle formation stage. The highest average nucleation rate of 360 cm−3 s−1 was observed for the OH-dominated nucleation events and the lowest aerosol mean formation rate less than 0.5 cm−3 s−1 for the case with only O3 present as an oxidant. On the other hand, ozonolysis of monoterpenes appears to be much more efficient to the aerosol growth process following nucleation. Higher contributions of more oxygenated products to the SOA mass loadings from OH-dominating oxidation systems were found as compared to the ozonolysis systems. Comparison of mass and volume distributions from the aerosol mass spectrometer and differential mobility analyzer yields estimated effective density of these SOA to be 1.34±0.06 g cm−3 with the OH plus O3 initiated oxidation systems and 1.38±0.03 g cm−3 with the ozonolysis dominated chemistry.

  3. Enhanced field-emission from a mixture of carbon nanotubes, ZnO tetrapods and conductive particles.

    Science.gov (United States)

    Wei, Lei; Xiaobing, Zhang; Zhiwei, Zhao; Jing, Chen; Yiping, Cui; Baoping, Wang

    2012-08-01

    We report the enhancement of field-emission current from a mixture of carbon nanotubes, ZnO tetrapod-like nano structures, and conductive particles. Carbon nanotubes are deposited on the electrode as the field emitters. A MgO layer is printed around the cathode electrode, and ZnO tetrapod-like nano structures are deposited on this layer for the generation of secondary emission electrons. A few conductive particles are also distributed on the MgO layer by spraying or screen-printing. These conductive particles enhance the transverse electric field around the cathode electrode. Consequently, more primary electrons emitted from the carbon nanotubes bombard on the ZnO tetrapods, and secondary emission electrons and scattered electrons are yielded. Finally, the field-emission current is enhanced obviously. As experimental results shown, a high field-emission current about 32 mA in a direct current emission mode has been obtained from a 0.5 cm2 emission site when an electric field of 9 V/microm is applied between cathode and anode. Compared with a conventional carbon nanotube cathode, the field-emission current has been improved about 80%.

  4. Generation mechanism of large-size invisible defects on Si epitaxial wafers

    Science.gov (United States)

    Lee, Kyuhyung; Park, Jungkil; Shin, Jungwon; Kim, Jayoung; Kang, Heebog; Lee, Boyoung

    2017-03-01

    The new Si epitaxial (epi) defects not seen in scanning electron microscope (SEM) measurements were investigated. Morphologies of these defects were measured by atomic force microscope (AFM) but source of defect was not found in transmission electron microscope (TEM) measurements. In order to find the origin of the invisible defect, we observed the morphological changes of the various substrate defects after epi growth process. Most of the defects were removed during hydrogen (H2) baking and hydrogen chloride (HCl) etching steps, but some particles survived. Among the survived defects, it was confirmed that the non-metallic particles having 200 nm or more were the origin of the invisible epi defects.

  5. Designing near-perfect invisibility cloaks

    DEFF Research Database (Denmark)

    Qiu, Min; Yan, Wei; Yan, Min

    2008-01-01

    Using the theory of transformation optics, practical cylindrical invisibility cloaks can be devised to conceal objects from detection at a targeted wavelength.......Using the theory of transformation optics, practical cylindrical invisibility cloaks can be devised to conceal objects from detection at a targeted wavelength....

  6. Development of a Reference Database for Particle-Induced Gamma-ray Emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dimitriou, P., E-mail: P.Dimitriou@iaea.org [International Atomic Energy Agency, Wagramerstrasse 5, A-1400 Vienna (Austria); Becker, H.-W. [Ruhr Universität Bochum, Gebäude NT05/130, Postfach 102148, Bochum 44721 (Germany); Bogdanović-Radović, I. [Department of Experimental Physics, Institute Rudjer Boskovic, Bijenicka Cesta 54, 10000 Zagreb (Croatia); Chiari, M. [Istituto Nazionale di Fisica Nucleare, Via Sansone 1, Sesto Fiorentino, 50019 Firenze (Italy); Goncharov, A. [Kharkov Institute of Physics and Technology, National Science Center, Akademicheskaya Str.1, Kharkov 61108 (Ukraine); Jesus, A.P. [Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa (Portugal); Kakuee, O. [Nuclear Science and Technology Research Institute, End of North Karegar Ave., PO Box 14395-836, Tehran (Iran, Islamic Republic of); Kiss, A.Z. [Institute of Nuclear Research (ATOMKI), Bem ter 18/c, PO Box 51, 4001 Debrecen (Hungary); Lagoyannis, A. [National Center of Scientific Research “Demokritos”, Agia Paraskevi, P.O. Box 60228, 15310 Athens (Greece); Räisänen, J. [Division of Materials Physics, Department of Physics, University of Helsinki, PO Box 43, 00014 University of Helsinki (Finland); Strivay, D. [Institut de Physique Nucleaire, Atomique et de Spectroscopie, Universite de Liège, Sart Tilman, B15 4000 Liège (Belgium); Zucchiatti, A. [Centro de Micro Análisis de Materiales, Universidad Autónoma de Madrid, Faraday 3, Madrid 28049 (Spain)

    2016-03-15

    Particle-Induced Gamma-ray Emission (PIGE) is a powerful analytical technique that exploits the interactions of rapid charged particles with nuclei located near a sample surface to determine the composition and structure of the surface regions of solids by measurement of characteristic prompt γ rays. The potential for depth profiling of this technique has long been recognized, however, the implementation has been limited owing to insufficient knowledge of the physical data and lack of suitable user-friendly computer codes for the applications. Although a considerable body of published data exists in the nuclear physics literature for nuclear reaction cross sections with γ rays in the exit channel, there is no up-to-date, comprehensive compilation specifically dedicated to IBA applications. A number of PIGE cross-section data had already been uploaded to the Ion Beam Analysis Nuclear Data Library (IBANDL) ( (http://www-nds.iaea.org/ibandl)) by members of the IBA community by 2011, however a preliminary survey of this body of unevaluated experimental data has revealed numerous discrepancies beyond the uncertainty limits reported by the authors. Using the resources and coordination provided by the IAEA, a concerted effort to improve the situation was made within the Coordinated Research Project on the Development of a Reference Database for PIGE spectroscopy, from 2011 to 2015. The aim of the CRP was to create a data library for Ion Beam Analysis that contains reliable and usable data on charged particle γ-ray emission cross sections that would be made freely available to the user community. As the CRP has reached its completion, we shall present its main achievements, including the results of nuclear cross-section evaluations and the development of a computer code that will become available to the public allowing for the implementation of a standardless PIGE technique.

  7. 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

  8. Primary and secondary particles chemical composition of marine emissions from Mediterranean seawaters

    Science.gov (United States)

    D'Anna, Barbara; Meme, Aurelie; Rmili, Badr; Pey, Jorge; Marchand, Nicolas; Schwier, Allison; Sellegri, Karine; Charriere, Bruno; Sempere, Richard; Mas, Sebastien; Parin, David

    2015-04-01

    Marine emissions are among the largest source of both primary particles and do highly contribute secondary organic aerosols (SOA) at a global scale. Whereas physical processes control the primary production of marine aerosols, biological activity is responsible for most of the organic fraction released from marine sources, potentially transformed into SOA when exposed to atmospheric oxidants. The Mediterranean atmosphere displays important concentrations of SOA, especially in summer, when atmospheric oxidants and photochemical activity are at their maximum. The origin of these elevated concentrations of SOA remain unclear. Here we present the results from a mesocosms study in a remote location in Corsica and a chamber study (using fresh sea water from Western Mediterranean) as part of the Source of marine Aerosol particles in the Mediterranean atmosphere (SAM) project. The mesocosm study was conducted at the Oceanographic and Marine Station STARESO (Corsica) in May 2013. One mesocosm was used as a control (with no enrichment) and the other two were enriched with nitrate and phosphate respecting Redfield ratio (N:P = 16) in order to produce a bloom of biological activity. Physical and chemical properties of the enclosed water samples together with their surrounding atmosphere were monitored during 20 days by a multi-instrumental high-time resolution set-up. In parallel, numerous additional measurements were conducted including water temperature, incident light, pH, conductivity, chemical and biological analyses, fluorescence of chlorophyll, dissolved oxygen concentration. The chamber studies were performed in a Teflon chamber of 1. 5m3 that accommodates a pyrex-container for the fresh sea-water samples. After injection of sea-water in the pyrex-container, the system is allowed to stabilize to 20-30 minutes, then it was exposed to 60-100ppbv of ozone and/or UV-A irradiation. Aerosol concentrations and their physical characteristics were followed by means of Scanning

  9. A Further Measurement of the beta-Delayed alpha-Particle Emission of 16N

    CERN Document Server

    III, R H F; McDonald, J E; Wilds, E L

    2007-01-01

    We measured the beta-delayed alpha-particle emission spectrum of 16N with a sensitivity for beta-decay branching ratios of the order of 10-10. The 16N nuclei were produced using the d(15N,16N)p reaction with 70 MeV 15N beams and a deuterium gas target 7.5 cm long at a pressure of 1250 torr. The 16N nuclei were collected (over 10 s) using a thin aluminum foil with an areal density of 180 mu g/cm2 tilted at 7 Deg with respect to the beam. The activity was transferred to the counting area by means of a stepping motor in less than 3 s with the counting carried out over 8 s. The beta-delayed alpha-particles were measured using a time of flight method to achieve a sufficiently low background. Standard calibration sources (148Gd, 241Am, 208,209Po, and 227Ac) as well as alpha-particles and 7Li from the 10B(n,alpha)7Li reaction were used for an accurate energy calibration. The energy resolution of the catcher foil (180-220 keV) was calculated and the time of flight resolution (3-10 nsec) was measured using the beta-de...

  10. Angular distribution in two-particle emission induced by neutrinos and electrons

    CERN Document Server

    Simo, I Ruiz; Amaro, J E; Barbaro, M B; Caballero, J A; Donnelly, T W

    2014-01-01

    The angular distribution of the phase space arising in two-particle emission reactions induced by electrons and neutrinos is computed in the laboratory (Lab) system by boosting the isotropic distribution in the center of mass (CM) system used in Monte Carlo generators. The Lab distribution has a singularity for some angular values, coming from the Jacobian of the angular transformation between CM and Lab systems. We recover the formula we obtained in a previous calculation for the Lab angular distribution. This is in accordance with the Monte Carlo method used to generate two-particle events for neutrino scattering~\\cite{Sob12}. Inversely, by performing the transformation to the CM system, it can be shown that the phase-space function, which is proportional to the two particle-two hole (2p-2h) hadronic tensor for a constant current operator, can be computed analytically in the frozen nucleon approximation, if Pauli blocking is absent. The results in the CM frame confirm our previous work done using an alterna...

  11. Particle emission from heavy-duty engine fuelled with blended diesel and biodiesel.

    Science.gov (United States)

    Martins, Leila Droprinchinski; da Silva Júnior, Carlos Roberto; Solci, Maria Cristina; Pinto, Jurandir Pereira; Souza, Davi Zacarias; Vasconcellos, Pérola; Guarieiro, Aline Lefol Nani; Guarieiro, Lílian Lefol Nani; Sousa, Eliane Teixeira; de Andrade, Jailson B

    2012-05-01

    In this study, particulate matter (PM) were characterized from a place impacted by heavy-duty vehicles (Bus Station) fuelled with diesel/biodiesel fuel blend (B3) in the city of Londrina, Brazil. Sixteen priority polycyclic aromatic hydrocarbons (PAH) concentrations were analyzed in the samples by their association with atmospheric PM, mass size distributions and major ions (fluorite, chloride, bromide, nitrate, phosphate, sulfate, nitrite, oxalate; fumarate, formate, succinate and acetate; lithium, sodium, potassium, magnesium, calcium and ammonium). Results indicate that major ions represented 21.2% particulate matter mass. Nitrate, sulfate, and ammonium, respectively, presented the highest concentration levels, indicating that biodiesel may also be a significant source for these ions, especially nitrate. Dibenzo[a,h]anthracene and indeno[1,2,3,-cd]pyrene were the main PAH found, and a higher fraction of PAH particles was found in diameters lower than 0.25 μm in Londrina bus station. The fine and ultrafine particles were dominant among the PM evaluated, suggesting that biodiesel decreases the total PAH emission. However, it does also increase the fraction of fine and ultrafine particles when compared to diesel.

  12. INSIDE in-beam positron emission tomography system for particle range monitoring in hadrontherapy.

    Science.gov (United States)

    Bisogni, Maria Giuseppina; Attili, Andrea; Battistoni, Giuseppe; Belcari, Nicola; Camarlinghi, Niccolo'; Cerello, Piergiorgio; Coli, Silvia; Del Guerra, Alberto; Ferrari, Alfredo; Ferrero, Veronica; Fiorina, Elisa; Giraudo, Giuseppe; Kostara, Eleftheria; Morrocchi, Matteo; Pennazio, Francesco; Peroni, Cristiana; Piliero, Maria Antonietta; Pirrone, Giovanni; Rivetti, Angelo; Rolo, Manuel D; Rosso, Valeria; Sala, Paola; Sportelli, Giancarlo; Wheadon, Richard

    2017-01-01

    The quality assurance of particle therapy treatment is a fundamental issue that can be addressed by developing reliable monitoring techniques and indicators of the treatment plan correctness. Among the available imaging techniques, positron emission tomography (PET) has long been investigated and then clinically applied to proton and carbon beams. In 2013, the Innovative Solutions for Dosimetry in Hadrontherapy (INSIDE) collaboration proposed an innovative bimodal imaging concept that combines an in-beam PET scanner with a tracking system for charged particle imaging. This paper presents the general architecture of the INSIDE project but focuses on the in-beam PET scanner that has been designed to reconstruct the particles range with millimetric resolution within a fraction of the dose delivered in a treatment of head and neck tumors. The in-beam PET scanner has been recently installed at the Italian National Center of Oncologic Hadrontherapy (CNAO) in Pavia, Italy, and the commissioning phase has just started. The results of the first beam test with clinical proton beams on phantoms clearly show the capability of the in-beam PET to operate during the irradiation delivery and to reconstruct on-line the beam-induced activity map. The accuracy in the activity distal fall-off determination is millimetric for therapeutic doses.

  13. Field emission enhancement of Au-Si nano-particle-decorated silicon nanowires

    Directory of Open Access Journals (Sweden)

    Zhao Fei

    2011-01-01

    Full Text Available Abstract Au-Si nano-particle-decorated silicon nanowire arrays have been fabricated by Au film deposition on silicon nanowire array substrates and then post-thermal annealing under hydrogen atmosphere. Field emission measurements illustrated that the turn-on fields of the non-annealed Au-coated SiNWs were 6.02 to 7.51 V/μm, higher than that of the as-grown silicon nanowires, which is about 5.01 V/μm. Meanwhile, after being annealed above 650°C, Au-Si nano-particles were synthesized on the top surface of the silicon nanowire arrays and the one-dimensional Au-Si nano-particle-decorated SiNWs had a much lower turn-on field, 1.95 V/μm. The results demonstrated that annealed composite silicon nanowire array-based electron field emitters may have great advantages over many other emitters.

  14. Invisibility in PT-symmetric complex crystals

    Energy Technology Data Exchange (ETDEWEB)

    Longhi, Stefano, E-mail: longhi@fisi.polimi.it [Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, I-20133 Milano (Italy)

    2011-12-02

    Bragg scattering in sinusoidal PT-symmetric complex crystals of finite thickness is theoretically investigated by the derivation of exact analytical expressions for reflection and transmission coefficients in terms of modified Bessel functions of first kind. The analytical results indicate that unidirectional invisibility, recently predicted for such crystals by coupled-mode theory (Z Lin et al 2011 Phys. Rev. Lett. http://dx.doi.org/10.1103/PhysRevLett.106.213901), breaks down for crystals containing a large number of unit cells. In particular, for a given modulation depth in a shallow sinusoidal potential, three regimes are encountered as the crystal thickness is increased. At short lengths the crystal is reflectionless and invisible when probed from one side (unidirectional invisibility), whereas at intermediate lengths the crystal remains reflectionless but not invisible; for longer crystals both unidirectional reflectionless and invisibility properties are broken. (paper)

  15. Invisible Intelligence Security System (IISS

    Directory of Open Access Journals (Sweden)

    Mubashir Ali,

    2011-06-01

    Full Text Available In this paper an attempt is made to fabricate an imperceptible/ invisible intelligence security system employing auto lock door practice which should distinguish between friend and foe. This is akin to a system which is mandatory to handle the situations resulting from the events like blasts/suicides attacks etc. A unique method of the secretive operated metal sensors system has been presented incorporating initially the Infra Red Transmitter and Infra Red Receiver at the gates for closing/opening purpose and then after the access to scan a human body instead of a having massive scanning system installed at the entrance gate of an organization/establishmentwhich is even indiscernible/ invisible to a human eye. This system will automatically scan a human body while passing above these metal detectors installed beneath the ground. In the event of possession of any kind of metal/weapon or any radioactive material the gate fitted with such system will not be opened automatically rather it will remained closed as retaliation/reprisal against the foe. For a friend to enter the gate this system will make use of password challenging technique which would be already known within the organization securely. Further this manuscript will also address the practical/technical issues confronting in its manifestation.

  16. Impact of the 0.1% fuel sulfur content limit in SECA on particle and gaseous emissions from marine vessels

    Science.gov (United States)

    Zetterdahl, Maria; Moldanová, Jana; Pei, Xiangyu; Pathak, Ravi Kant; Demirdjian, Benjamin

    2016-11-01

    Emissions were measured on-board a ship in the Baltic Sea, which is a sulfur emission control area (SECA), before and after the implementation of the strict fuel sulfur content (FSC) limit of 0.1 m/m% S on the 1st of January 2015. Prior to January 2015, the ship used a heavy fuel oil (HFO) but switched to a low-sulfur residual marine fuel oil (RMB30) after the implementation of the new FSC limit. The emitted particulate matter (PM) was measured in terms of mass, number, size distribution, volatility, elemental composition, content of organics, black and elemental carbon, polycyclic aromatic hydrocarbons (PAHs), microstructure and micro-composition, along with the gaseous emissions at different operating conditions. The fuel change reduced emissions of PM mass up to 67%. The number of particles emitted remained unchanged and were dominated by nanoparticles. Furthermore, the fuel change resulted in an 80% reduction of SO2 emissions and decreased emissions of total volatile organic compounds (VOCs). The emissions of both monoaromatic and lighter polyaromatic hydrocarbon compounds increased with RMB30, while the heavy, PM-bound PAH species that belong to the carcinogenic PAH family were reduced. Emissions of BC remained similar between the two fuels. This study indicates that the use of low-sulfur residual marine fuel oil is a way to comply with the new FSC regulation and will reduce the anthropogenic load of SO2 emissions and secondary PM formed from SO2. Emissions of primary particles, however, remain unchanged and do not decrease as much as would be expected if distilled fuel was used. This applies both to the number of particles emitted and some toxic components, such as heavy metals, PAHs or elemental carbon (EC). The micro-composition analyses showed that the soot particles emitted from RMB30 combustion often do not have any trace of sulfur compared with particles from HFO combustion, which always have a sulfur content over 1%m/m. The soot sulfur content can

  17. Traffic induced particle resuspension in Paris: Emission factors and source contributions

    Science.gov (United States)

    Amato, F.; Favez, O.; Pandolfi, M.; Alastuey, A.; Querol, X.; Moukhtar, S.; Bruge, B.; Verlhac, S.; Orza, J. A. G.; Bonnaire, N.; Le Priol, T.; Petit, J.-F.; Sciare, J.

    2016-03-01

    Gaining knowledge on the process of particle resuspension from urban paved roads is of particular importance considering the increasing relevance of this source in urban air quality management and the lack of basic information on emission factors and source contributions. In this study we performed extensive field measurements for the quantification of the emission factors from different types of road in the city of Paris, and investigated the causes of their variability and the contributions to the ambient air PM10 observed across one year at one traffic monitoring site in the ring road of Paris. Results show agreement between lower road dust loadings (RD10: 0.7-2.2 mg m-2) and emission factors (5.4-9.0 mg vehicle-1 km-1) at inner-roads of Paris, compared to the ring road (2.4 mg m-2 and 17 mg vehicle-1 km-1, respectively), where the two parameters are estimated independently. The higher values in the ring road were likely caused by the poor state of pavement and higher share of heavy duty vehicles. Road wear, brake wear and a carbonaceous source, were almost equally responsible for 96% of RD10. At the traffic monitoring site located at the ring road (220,000 vehicle/day), the contributions of road dust emissions were estimated by receptor modeling to be 13% of PM10 on an annual mean (6.3 μg m-3), while the sum of vehicle exhaust and wear accounted for 47% resulting in a total traffic contribution of 60% of PM10. Road salting resulted to be a minor contributor (1% of annual mean) also in winter time (2%).

  18. Variability of particle number emissions from diesel and hybrid diesel-electric buses in real driving conditions.

    Science.gov (United States)

    Sonntag, Darrell B; Gao, H Oliver; Holmén, Britt A

    2008-08-01

    A linear mixed model was developed to quantify the variability of particle number emissions from transit buses tested in real-world driving conditions. Two conventional diesel buses and two hybrid diesel-electric buses were tested throughout 2004 under different aftertreatments, fuels, drivers, and bus routes. The mixed model controlled the confounding influence of factors inherent to on-board testing. Statistical tests showed that particle number emissions varied significantly according to the after treatment, bus route, driver, bus type, and daily temperature, with only minor variability attributable to differences between fuel types. The daily setup and operation of the sampling equipment (electrical low pressure impactor) and mini-dilution system contributed to 30-84% of the total random variability of particle measurements among tests with diesel oxidation catalysts. By controlling for the sampling day variability, the model better defined the differences in particle emissions among bus routes. In contrast, the low particle number emissions measured with diesel particle filters (decreased by over 99%) did not vary according to operating conditions or bus type but did vary substantially with ambient temperature.

  19. Chemistry of new particle growth in mixed urban and biogenic emissions – insights from CARES

    Energy Technology Data Exchange (ETDEWEB)

    Setyan, Ari; Song, Chen; Merkel, M.; Knighton, M.; Onasch, Timothy B.; Canagaratna, M. R.; Worsnop, Douglas R.; Wiedensohler, A.; Shilling, John E.; Zhang, Qi

    2014-07-01

    plumes. In addition, the concentrations of species representative of urban emissions (e.g., black carbon,CO, NOx, and toluene) were significantly higher whereas thephoto-oxidation products of biogenic VOCs (volatile organic compounds) and the biogenically influenced SOA also increased moderately during the NPE days compared to the non-event days. These results indicate that the frequently occurring NPEs over the Sacramento and Sierra Nevada regions were mainly driven by urban plumes from Sacramento and the San Francisco Bay Area, and that the interaction of regional biogenic emissions with the urban plumes has enhanced the new particle growth. This finding has important implications for quantifying the climate impacts of NPEs on global scale.

  20. Decadal-scale trends in regional aerosol particle properties and their linkage to emission changes

    Science.gov (United States)

    Zhao, Bin; Jiang, Jonathan H.; Gu, Yu; Diner, David; Worden, John; Liou, Kuo-Nan; Su, Hui; Xing, Jia; Garay, Michael; Huang, Lei

    2017-05-01

    Understanding long-term trends in aerosol loading and properties is essential for evaluating the health and climatic effects of these airborne particulates as well as the effectiveness of pollution control policies. While many studies have used satellite data to examine the trends in aerosol optical depth (AOD), very few have investigated the trends in aerosol properties associated with particle size, morphology, and light absorption. In this study, we investigate decadal-scale (13-15 year) trends in aerosol loading and properties during 2001-2015 over three populous regions: the Eastern United States (EUS), Western Europe (WEU), and Eastern and Central China (ECC). We use observations from MISR (Multi-angle Imaging SpectroRadiometer) and MODIS (Moderate resolution Imaging Spectroradiometer). Relationships between aerosol property trends and air pollutant emission changes are examined. We find that annual mean AOD shows pronounced decreasing trends over EUS and WEU regions, as a result of considerable emission reductions in all major pollutants except for mineral dust and ammonia (NH3). Over the ECC region, AOD increases before 2006 due to emission increases induced by rapid economic development, fluctuates between 2006 and 2011, and subsequently decreases after 2011 in conjunction with effective emission reduction in anthropogenic primary aerosols, sulfur dioxide (SO2), and nitrogen oxides (NOx). The fraction of small-size AOD (1.4 μm diameter), nonspherical and absorbing AOD have generally shown increasing trends over EUS and WEU regions, indicating that fine and light-scattering aerosol constituents have been more effectively reduced than coarse and light-absorbing constituents. These trends are consistent with the larger reduction ratios in SO2 and NOx emissions than in primary aerosols, including mineral dust and black carbon (BC). Over the ECC region, no significant trends are observed with respect to size distribution, morphology, or light absorption, which

  1. Simultaneous coastal measurements of ozone deposition fluxes and iodine-mediated particle emission fluxes with subsequent CCN formation

    Directory of Open Access Journals (Sweden)

    J. D. Whitehead

    2010-01-01

    Full Text Available Here we present the first observations of simultaneous ozone deposition fluxes and ultrafine particle emission fluxes over an extensive infra-littoral zone. Fluxes were measured by the eddy covariance technique at the Station Biologique de Roscoff, on the coast of Brittany, north-west France. This site overlooks a very wide (3 km littoral zone controlled by very deep tides (9.6 m exposing extensive macroalgae beds available for significant iodine mediated photochemical production of ultrafine particles. The aspect at the Station Biologique de Roscoff provides an extensive and relatively flat, uniform fetch within which micrometeorological techniques may be utilized to study links between ozone deposition to macroalgae (and sea water and ultrafine particle production.

    Ozone deposition to seawater at high tide was significantly slower (vd[O3]=0.302±0.095 mm s−1 than low tidal deposition. A statistically significant difference in the deposition velocities to macroalgae at low tide was observed between night time (vd[O3]=1.00±0.10 mm s−1 and daytime (vd[O3]=2.05±0.16 mm s−1 when ultrafine particle formation results in apparent particle emission. Very high emission fluxes of ultrafine particles were observed during daytime periods at low tides ranging from 50 000 particles cm−2 s−1 to greater than 200 000 particles cm−2 s−1 during some of the lowest tides. These emission fluxes exhibited a significant relationship with particle number concentrations comparable with previous observations at another location. Apparent particle growth rates were estimated to be in the range 17–150 nm h−1 for particles in the size range 3–10 nm. Under certain conditions, particle growth may be inferred to continue to greater than 120 nm over tens

  2. Size-Resolved Particle Number and Volume Emission Factors for On-Road Gasoline and Diesel Motor Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Ban-Weiss, George A.; Lunden, Melissa M.; Kirchstetter, Thomas W.; Harley, Robert A.

    2009-04-10

    Average particle number concentrations and size distributions from {approx}61,000 light-duty (LD) vehicles and {approx}2500 medium-duty (MD) and heavy-duty (HD) trucks were measured during the summer of 2006 in a San Francisco Bay area traffic tunnel. One of the traffic bores contained only LD vehicles, and the other contained mixed traffic, allowing pollutants to be apportioned between LD vehicles and diesel trucks. Particle number emission factors (particle diameter D{sub p} > 3 nm) were found to be (3.9 {+-} 1.4) x 10{sup 14} and (3.3 {+-} 1.3) x 10{sup 15} kg{sup -1} fuel burned for LD vehicles and diesel trucks, respectively. Size distribution measurements showed that diesel trucks emitted at least an order of magnitude more particles for all measured sizes (10 < D{sub p} < 290 nm) per unit mass of fuel burned. The relative importance of LD vehicles as a source of particles increased as D{sub p} decreased. Comparing the results from this study to previous measurements at the same site showed that particle number emission factors have decreased for both LD vehicles and diesel trucks since 1997. Integrating size distributions with a volume weighting showed that diesel trucks emitted 28 {+-} 11 times more particles by volume than LD vehicles, consistent with the diesel/gasoline emission factor ratio for PM{sub 2.5} mass measured using gravimetric analysis of Teflon filters, reported in a companion paper.

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

    Science.gov (United States)

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

    2015-12-01

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

  4. A positron emission particle tracking investigation of the flow regimes in tumbling mills

    Science.gov (United States)

    Govender, I.; Pathmathas, T.

    2017-01-01

    Using positron emission particle tracking (PEPT) data we recover key granular rheology ingredients (velocity, shear rate, volume concentration, bed depth) for developing, testing and calibrating granular flow models. In this regard, 5 mm glass beads were rotated within a 476 mm diameter mill fitted with angled lifter bars along the inner azimuthal walls and operated in batch mode across a range of drum rotation speeds that span cascading and cataracting Froude regimes. After averaging the PEPT outputs into representative volume elements, subsequent continuum analysis of the flowing layer revealed a rich coexistence of flow regimes: a quasi-static layer dominated by frictional interactions, a dense, liquid-like layer that is stressed by frictional and collisional interactions, and an inertial layer that interacts mainly through collisions. Combining the inertial number with an empirically formulated dilatancy law and the measured granular rheological ingredients then facilitated the recovery of the total depth-dependent pressure of the free surface layer.

  5. Further evidence of nuclear reactions in the Pd/D lattice: emission of charged particles.

    Science.gov (United States)

    Szpak, Stanislaw; Mosier-Boss, Pamela A; Gordon, Frank E

    2007-06-01

    Almost two decades ago, Fleischmann and Pons reported excess enthalpy generation in the negatively polarized Pd/D-D2O system, which they attributed to nuclear reactions. In the months and years that followed, other manifestations of nuclear activities in this system were observed, viz. tritium and helium production and transmutation of elements. In this report, we present additional evidence, namely, the emission of highly energetic charged particles emitted from the Pd/D electrode when this system is placed in either an external electrostatic or magnetostatic field. The density of tracks registered by a CR-39 detector was found to be of a magnitude that provides undisputable evidence of their nuclear origin. The experiments were reproducible. A model based upon electron capture is proposed to explain the reaction products observed in the Pd/D-D2O system.

  6. $\\beta$-particle energy-summing correction for $\\beta$-delayed proton emission measurements

    CERN Document Server

    Meisel, Z; Crawford, H L; Cyburt, R H; Grinyer, G F; Langer, C; Montes, F; Schatz, H; Smith, K

    2016-01-01

    A common approach to studying $\\beta$-delayed proton emission is to measure the energy of the emitted proton and corresponding nuclear recoil in a double-sided silicon-strip detector (DSSD) after implanting the $\\beta$-delayed proton emitting ($\\beta$p) nucleus. However, in order to extract the proton-decay energy, the measured energy must be corrected for the additional energy implanted in the DSSD by the $\\beta$-particle emitted from the $\\beta$p nucleus, an effect referred to here as $\\beta$-summing. We present an approach to determine an accurate correction for $\\beta$-summing. Our method relies on the determination of the mean implantation depth of the $\\beta$p nucleus within the DSSD by analyzing the shape of the total (proton + recoil + $\\beta$) decay energy distribution shape. We validate this approach with other mean implantation depth measurement techniques that take advantage of energy deposition within DSSDs upstream and downstream of the implantation DSSD.

  7. Detection of halogenated flame retardants in polyurethane foam by particle induced X-ray emission

    Energy Technology Data Exchange (ETDEWEB)

    Maley, Adam M.; Falk, Kyle A.; Hoover, Luke; Earlywine, Elly B.; Seymour, Michael D. [Department of Chemistry, Hope College, 35 E. 12th Street, Holland, MI 49423 (United States); DeYoung, Paul A. [Department of Physics, Hope College, 27 Graves Place, Holland, MI 49423 (United States); Blum, Arlene [Green Science Policy Institute, Box 5455, Berkeley, CA 94705 (United States); Stapleton, Heather M. [Nicholas School of the Environment, Duke University, LSRC Box 90328, Durham, NC 27708 (United States); Peaslee, Graham F., E-mail: peaslee@hope.edu [Department of Chemistry, Hope College, 35 E. 12th Street, Holland, MI 49423 (United States)

    2015-09-01

    A novel application of particle-induced X-ray emission (PIXE) has been developed to detect the presence of chlorinated and brominated flame retardant chemicals in polyurethane foams. Traditional Gas Chromatography–Mass Spectrometry (GC–MS) methods for the detection and identification of halogenated flame retardants in foams require extensive sample preparation and data acquisition time. The elemental analysis of the halogens in polyurethane foam performed by PIXE offers the opportunity to identify the presence of halogenated flame retardants in a fraction of the time and sample preparation cost. Through comparative GC–MS and PIXE analysis of 215 foam samples, excellent agreement between the two methods was obtained. These results suggest that PIXE could be an ideal rapid screening method for the presence of chlorinated and brominated flame retardants in polyurethane foams.

  8. Boron analysis for neutron capture therapy using particle-induced gamma-ray emission.

    Science.gov (United States)

    Nakai, Kei; Yamamoto, Yohei; Okamoto, Emiko; Yamamoto, Tetsuya; Yoshida, Fumiyo; Matsumura, Akira; Yamada, Naoto; Kitamura, Akane; Koka, Masashi; Satoh, Takahiro

    2015-12-01

    The neutron source of BNCT is currently changing from reactor to accelerator, but peripheral facilities such as a dose-planning system and blood boron analysis have still not been established. To evaluate the potential application of particle-induced gamma-ray emission (PIGE) for boron measurement in clinical boron neutron capture therapy, boronophenylalanine dissolved within a cell culture medium was measured using PIGE. PIGE detected 18 μgB/mL f-BPA in the culture medium, and all measurements of any given sample were taken within 20 min. Two hours of f-BPA exposure was required to create a boron distribution image. However, even though boron remained in the cells, the boron on the cell membrane could not be distinguished from the boron in the cytoplasm. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Emissions and measure analysis of fine particles 2000-2020; Emissionen und Massnahmenanalyse Feinstaub 2000-2020

    Energy Technology Data Exchange (ETDEWEB)

    Joerss, Wolfram; Handke, Volker [Institut fuer Zukunftsstudien und Technologiebewertung gGmbH (IZT), Berlin (Germany)

    2007-08-15

    With this study, the Federal Environmental Agency's emission inventory on total suspended particles and the fine fractions PM{sub 1}0 and PM{sub 2}.5 was updated. On that basis, a reference scenario was developed for anthropogenic emissions of particulate matter up to the years 2010, 2015 and 2020. In addition, potential additional emission reduction measures were systematically collected and quantified. At the source groups which contribute most strongly to the emissions there are clear differences between the fine fractions and in the course of time. In particular, with the total fine the emission freight is very broadly distributed over many source groups. With PM{sub 2}.5, the emissions are more strongly concentrated on a limited number of source groups. The decrease of the emissions in the years between 2000 and 2020 in the reference scenario takes place in source groups with high portions of PM{sub 2}.5 of the emissions of total fine particles.

  10. Pre-equilibrium α-particle emission as a probe to study α-clustering in nuclei

    Directory of Open Access Journals (Sweden)

    Fotina O.V.

    2014-03-01

    Full Text Available A theoretical approach was developed to describe secondary particle emission in heavy ion collisions, with special regards to pre-equilibrium α-particle production. The probabilities of neutron, proton and α-particle emission have been evaluated for both the equilibrium and pre-equilibrium stages of the process. Effects due the possible cluster structure of the projectile which has been excited during the collisions have been experimentally evidenced studying the double differential cross sections of p and α-particles emitted in the E=250MeV 16O +116Sn reaction. Calculations within the present model with different clusterization probabilities have been compared to the experimental data.

  11. Particle emissions from ventilation equipment: health hazards, measurement and product development; Ilmanvaihtolaitteiden hiukkaspaeaestoet: terveyshaitat, mittaaminen ja tuotekehitys

    Energy Technology Data Exchange (ETDEWEB)

    Tossavainen, A.; Tuovila, H.; Riala, R.; Harju, R.; Tuomi, T.; Voutilainen, R. [Tyoeterv.l, Helsinki (Finland); Laamanen, J.; Ismo Heimonen, I.; Kovanen, K. [VTT, Espoo (Finland)

    2006-10-15

    The project aimed to develop the design, structure and materials of ventilation equipment for the improvement of indoor air quality in office- type buildings. Particle emissions from commercial sound silencers were measured by laboratory tests. In ten buildings, the dust and fibre levels were surveyed in relation to the product design and operation. Direct-reading particle counters and filter sampling methods combined with optical and electron microscopy analyses were the main methods in these surveys. Nasal lavage was used for the estimation of inhalation exposure to coarse man-made mineral fibres. Technical criteria were drafted for the design and testing of fibre emissions from various ventilation equipment. (orig.)

  12. Effects of fresh lubricant oils on particle emissions emitted by a modern gasoline direct injection passenger car.

    Science.gov (United States)

    Pirjola, Liisa; Karjalainen, Panu; Heikkilä, Juha; Saari, Sampo; Tzamkiozis, Theodoros; Ntziachristos, Leonidas; Kulmala, Kari; Keskinen, Jorma; Rönkkö, Topi

    2015-03-17

    Particle emissions from a modern turbocharged gasoline direct injection passenger car equipped with a three-way catalyst and an exhaust gas recirculation system were studied while the vehicle was running on low-sulfur gasoline and, consecutively, with five different lubrication oils. Exhaust particle number concentration, size distribution, and volatility were determined both at laboratory and on-road conditions. The results indicated that the choice of lubricant affected particle emissions both during the cold start and warm driving cycles. However, the contribution of engine oil depended on driving conditions being higher during acceleration and steady state driving than during deceleration. The highest emission factors were found with two oils that had the highest metal content. The results indicate that a 10% decrease in the Zn content of engine oils is linked with an 11-13% decrease to the nonvolatile particle number emissions in steady driving conditions and a 5% decrease over the New European Driving Cycle. The effect of lubricant on volatile particles was even higher, on the order of 20%.

  13. Determining gaseous emission factors and driver's particle exposures during traffic congestion by vehicle-following measurement techniques.

    Science.gov (United States)

    Tang, U Wa; Wang, Zhishi

    2006-11-01

    Vehicle gaseous emissions (NO, CO, CO2, and hydrocarbon [HC]) and driver's particle exposures (particulate matter traffic congestion in Macao, Special Administrative Region, People's Republic of China, an urban area having one of the highest population densities in the world. The measurements were taken with high time resolution so that fluctuations in the emissions can be seen readily during vehicle acceleration, cruising, deceleration, and idling. The tests were conducted in close proximity to the vehicles, with the inlet of a five-gas analyzer mounted on the front bumper of the mobile laboratory, and the distance between the vehicles was usually within several meters. To measure the driver's particle exposures, the inlets of the particle analyzers were mounted at the height of the driver's breathing position in the mobile laboratory, with the driver's window open. A total of 178 and 113 vehicles were followed individually to determine the gaseous emission factor and the driver's particle exposures, respectively, for motorcycle, passenger car, taxi, truck, and bus. The gaseous emission factors were used to model the roadside air quality, and good correlations between the modeled and monitored CO, NO2, and nitrogen oxide (NO(x)) verified the reliability of the experiments. Compared with petrol passenger cars and petrol trucks, diesel taxies and diesel trucks emitted less CO but more NO(x). The impact of urban canyons is shown to cause a significant increase in the PM1 peak. The background concentrations contributed a significant amount of the driver's particle exposures.

  14. Particle acceleration and radio emission for SGRs/AXPs as white dwarf pulsars

    Science.gov (United States)

    Lobato, R. V.; Coelho, Jaziel; Malheiro, M.

    2015-07-01

    Recently, an alternative model based on white dwarfs pulsars has been proposed to explain a class of pulsars known as Soft Gamma Repeaters (SGR) and Anomalus X-Ray Pulsars (AXP) [6][4], usually named as magnetars. In this model the magnetized white dwarfs can have surface magnetic field B ∼ 107 — 1010G and rotate very fast with frequencies ω ∼ 1 rad/s, allowing them to produce large electromagnetic (EM) potentials and generate electron-positron pairs. These EM potentials are comparable with the ones of neutron stars pulsars with strong magnetic fields. In our study we consider two possible processes associated with the particle acceleration: in one we have the pair production near to the star polar caps i.e., inside the light cylinder where magnetic-field lines are closed, on the other the creation of pair is in the Outer Magnetosphere i.e., far away of the star surface where magnetic field are open [1]. This analysis of the possibility of radio emission was done for all the 23 SGRs/AXPs of the McGill Online Magnetar Catalog [7] that contains the current information available on these sources. Our work is a first attempted to find an explanation for the puzzle why for all the SGRs/AXPs was expected radio emission, but it was observed in only four of them.

  15. Forensic analysis of tempered sheet glass by particle induced X-ray emission (PIXE)

    Energy Technology Data Exchange (ETDEWEB)

    Jisonna, L.J. [Department of Chemistry and Department of Physics, Hope College, Holland, MI 49422-9000 (United States); DeYoung, P.A., E-mail: deyoung@hope.ed [Department of Chemistry and Department of Physics, Hope College, Holland, MI 49422-9000 (United States); Ferens, J.; Hall, C.; Lunderberg, J.M.; Mears, P. [Department of Chemistry and Department of Physics, Hope College, Holland, MI 49422-9000 (United States); Padilla, D. [Department of Physics, San Diego State University, San Diego, CA 92182-1233 (United States); Peaslee, G.F. [Department of Chemistry and Department of Physics, Hope College, Holland, MI 49422-9000 (United States); Sampson, R. [Department of Physics, Columbia University, New York, NY 10027 (United States)

    2011-05-15

    Highlights: {yields} PIXE was found to give the same results for trace elements in glass as ICP. {yields} PIXE can non-destructively determine trace element concentrations in auto glass. {yields} Measured Ca, Fe, Ti, Mn, and Sr in auto glass with PIXE. -- Abstract: The elemental concentrations of five trace elements in tempered sheet glass fragments were determined using particle-induced X-ray emission (PIXE) spectrometry. The trace element concentrations for calcium, iron, manganese, strontium, and titanium are compared to those obtained by inductively-coupled plasma-atomic emission spectrometry (ICP-AES) following complete digestion by hydrofluoric acid. For these five elements, the absolute concentrations obtained by both methods are shown to agree well over a wide range of concentrations. The limits of detection for trace elements are typically lower for the ICP-AES method. However, we show that the concentrations of these five elements can be accurately measured by the PIXE method. Since PIXE is an entirely non-destructive method, there exists a niche for this technique to be used as a complement to the more sensitive ICP-AES technique in the forensic analysis of sheet glass.

  16. Angular profile of Particle Emission from a Higher-dimensional Black Hole: Analytic Results

    CERN Document Server

    Kanti, Panagiota

    2012-01-01

    During the spin-down phase of the life of a higher-dimensional black hole, the emission of particles on the brane exhibits a strong angular variation with respect to the rotation axis of the black hole. It has been suggested that this angular variation is the observable that could disentangle the dependence of the radiation spectra on the number of extra dimensions and angular momentum of the black hole. Working in the low-energy regime, we have employed analytical formulae for the greybody factors, angular eigenvalues and eigenfunctions of fermions and gauge bosons, and studied the characteristics of the corresponding angular profiles of emission spectra in terms of only a few dominant partial modes. We have confirmed that, in the low-energy channel, the emitted gauge bosons become aligned to the rotation axis of the produced black hole while fermions form an angle with the rotation axis whose exact value depends on the angular-momentum of the black hole. In the case of scalar fields, we demonstrated the exi...

  17. Pulsed VHE emission from the Crab Pulsar in the context of magnetocentrifugal particle acceleration

    CERN Document Server

    Osmanov, Z

    2016-01-01

    The Crab Pulsar has been recently detected at very high energies (VHE) with its pulsed VHE emission reaching up to $1.5$ TeV. The VHE peaks appear synchronised with the peaks at GeV energies and show VHE spectra following hard power-law functions. These new findings have been interpreted as evidence for a gamma-ray production that happens very close to the light cylinder. Motivated by these experimental results we consider the efficiency of magnetocentrifugal particle acceleration in the magnetosphere of the Crab Pulsar, reexamining and extending results obtained in a previous work (Osmanov & Rieger 2009). It is shown that efficient magnetocentrifugal acceleration close to the light cylinder could provide the required electron Lorentz factors of $5\\times 10^6$ and that the resulting inverse Compton (IC) scattering off thermal photons might explain the enigmatic TeV emission of the pulsar. We estimate the corresponding VHE luminosity and provide a derivation of its spectral characteristics, that appear rem...

  18. Why Information Literacy Is Invisible

    Directory of Open Access Journals (Sweden)

    William Badke

    2011-03-01

    Full Text Available Despite the many information literacy programs on higher education campuses, the literature of information literacy and the concept of information literacy as a viable academic subject remain hidden to most professors and academic administrators. Information literacy is invisible to academia because it is misunderstood, academic administrators have not put it on their institutions' agendas, the literature of information literacy remains in the library silo, there is a false belief that information literacy is acquired only by experience, there is a false assumption that technological ability is the same as information literacy, faculty culture makes information literacy less significant than other educational pursuits, faculty have a limited perception of the ability of librarians. and accrediting bodies have not yet advanced information literacy to a viable position in higher education. The new information age demands that these barriers be overcome and information literacy take a prominent place within the academic experience.

  19. Hidden progress: broadband plasmonic invisibility

    CERN Document Server

    Renger, Jan; Dupont, Guillaume; Aćimović, Srdjan S; Guenneau, Sébastien; Quidant, Romain; Enoch, Stefan

    2010-01-01

    The key challenge in current research into electromagnetic cloaking is to achieve invisibility over an extended bandwidth. There has been significant progress towards this using the idea of cloaking by sweeping under the carpet of Li and Pendry, with dielectric structures superposed on a mirror. Here, we show that we can harness surface plasmon polaritons at a metal surface structured with a dielectric material to obtain a unique control of their propagation. We exploit this to control plasmonic coupling and demonstrate both theoretically and experimentally cloaking over an unprecedented bandwidth (650-900 nm). Our non-resonant plasmonic metamaterial allows a curved reflector to mimic a flat mirror. Our theoretical predictions are validated by experiments mapping the surface light intensity at the wavelength 800 nm.

  20. The effect of dust emissions from open storage piles to particle ambient concentration and human exposure.

    Science.gov (United States)

    Chalvatzaki, E; Aleksandropoulou, V; Glytsos, T; Lazaridis, M

    2012-12-01

    The current study focus on the determination of dust emissions from piles in open storage yards of a municipal solid waste (MSW) composting site and the subsequent atmospheric dust dispersion. The ISC3-ST (Industrial Source Complex Version 3 - Short Term) model was used for the evaluation of the PM(10) ambient concentrations associated with the dispersion of MSW compost dust emissions in air. Dust emission rates were calculated using the United States Environmental Protection Agency proposed dust resuspension formulation from open storage piles using local meteorological data. The dispersion modelling results on the spatial distribution of PM(10) source depletion showed that the maximum concentrations were observed at a distance 25-75 m downwind of the piles in the prevailing wind direction. Sensitivity calculations were performed also to reveal the effect of the compost pile height, the friction velocity and the receptor height on the ambient PM(10) concentration. It was observed that PM(10) concentrations (downwind in the prevailing wind direction) increased with increasing the friction velocity, increasing the pile height (for distances greater than 125 m from the source) and decreasing the receptor height (for distances greater than 125 m from the source). Furthermore, the results of ISC3-ST were analysed with the ExDoM (Exposure Dose Model) human exposure model. The ExDoM is a model for calculating the human exposure and the deposition dose, clearance, and finally retention of aerosol particles in the human respiratory tract (RT). PM(10) concentration at the composting site was calculated as the sum of the concentration from compost pile dust resuspension and the background concentration. It was found that the exposure to PM(10) and deposited lung dose for an adult Caucasian male who is not working at the composting site is less by 20-74% and 29-84%, respectively, compared to those for a worker exposed to PM concentrations at the composting site.

  1. Light Particle Emission Mechanisms in Heavy-Ion Reactions at 5-20 MeV/u

    Directory of Open Access Journals (Sweden)

    Fotina O.V.

    2010-03-01

    Full Text Available Light Charged Particle emission mechanisms were studied for different mass entrance channel nuclear reactions. The 300, 400, 500 MeV 64Ni + 68Zn and 130, 250 MeV 16O + 116Sn reactions were measured at the Legnaro National Laboratory using the beams from the TANDEM-ALPI acceleration system. Light Charged Particles were measured in coincidence with Evaporation Residues and their spectra were analyzed using the global moving source fit technique. The characterization of different emission sources (evaporative, pre-equilibrium, break-up is discussed. The behavior of pre-equilibrium emission as a function of projectile energy, excitation energy and mass-asymmetry in the entrance channel was studied, evaluating the energy, mass and charge lost by the composite systems and using Griffin exciton model for the pre-equilibrium neutron emission. The present results are compared with the systematics of the asymmetric mass entrance channel reactions. The present work shows that also at the onset the pre-equilibrium emission depends not only on the projectile velocity but also on the reaction entrance channel mass-asymmetry. The first attempt of the particle spectra analysis using the Griffin exciton model is demonstrated for the case of proton emission in the 130 MeV 16O + 116Sn reaction.

  2. Alfvenic behavior of alpha particle driven ion cyclotron emission in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Cauffman, S.; Majeski, R. [Princeton Plasma Physics Lab., NJ (United States); McClements, K.G. [UKAEA Government Division, Oxfordshire (United Kingdom). Euratom/UKAEA Fusion Association] [and others

    1995-07-01

    Ion cyclotron emission (ICE) has been observed during D-T discharges in the Tokamak Fusion Test Reactor (TFTR), using rf probes located near the top and bottom of the vacuum vessel. Harmonics of the alpha cyclotron frequency ({Omega}{sub {alpha}}) evaluated at the outer midplane plasma edge are observed at the onset of the beam injection phase of TFTR supershots, and persist for approximately 100-250 ms. These results are in contrast with observations of ICE in JET, in which harmonics of {Omega}{sub {alpha}} evolve with the alpha population in the plasma edge. Such differences are believed to be due to the fact that newly-born fusion alpha particles are super-Alfvenic near the edge of JET plasmas, while they are sub-Alfvenic near the edge of TFTR supershot plasmas. In TFTR discharges with edge densities such that newly-born alpha particles are super-Alfvenic, alpha cyclotron harmonics are observed to persist. These results are in qualitative agreement with numerical calculations of growth rates due to the magnetoacoustic cyclotron instability.

  3. Geometry and light the science of invisibility

    CERN Document Server

    Leonhardt, Ulf

    2010-01-01

    The science of invisibility combines two of physics' greatest concepts: Einstein's general relativity and Maxwell's principles of electromagnetism. Recent years have witnessed major breakthroughs in the area, and the authors of this volume - Ulf Leonhardt and Thomas Philbin of Scotland's University of St. Andrews - have been active in the transformation of invisibility from fiction into science. Their work on designing invisibility devices is based on modern metamaterials, inspired by Fermat's principle, analogies between mechanics and optics, and the geometry of curved space. Suitable for gra

  4. Broadband invisibility by non-Euclidean cloaking.

    Science.gov (United States)

    Leonhardt, Ulf; Tyc, Tomás

    2009-01-02

    Invisibility and negative refraction are both applications of transformation optics where the material of a device performs a coordinate transformation for electromagnetic fields. The device creates the illusion that light propagates through empty flat space, whereas in physical space, light is bent around a hidden interior or seems to run backward in space or time. All of the previous proposals for invisibility require materials with extreme properties. Here we show that transformation optics of a curved, non-Euclidean space (such as the surface of a virtual sphere) relax these requirements and can lead to invisibility in a broad band of the spectrum.

  5. Trends in black carbon and size-resolved particle number concentrations and vehicle emission factors under real-world conditions

    Science.gov (United States)

    Krecl, Patricia; Johansson, Christer; Targino, Admir Créso; Ström, Johan; Burman, Lars

    2017-09-01

    Kerbside concentrations of NOx, black carbon (BC), total number of particles (diameter > 4 nm) and number size distribution (28-410 nm) were measured at a busy street canyon in Stockholm in 2006 and 2013. Over this period, there was an important change in the vehicle fleet due to a strong dieselisation process of light-duty vehicles and technological improvement of vehicle engines. This study assesses the impact of these changes on ambient concentrations and particle emission factors (EF). EF were calculated by using a novel approach which combines the NOx tracer method with positive matrix factorisation (PMF) applied to particle number size distributions. NOx concentrations remained rather constant between these two years, whereas a large decrease in particle concentrations was observed, being on average 60% for BC, 50% for total particle number, and 53% for particles in the range 28-100 nm. The PMF analysis yielded three factors that were identified as contributions from gasoline vehicles, diesel fleet, and urban background. This separation allowed the calculation of the average vehicle EF for each particle metric per fuel type. In general, gasoline EF were lower than diesel EF, and EF for 2013 were lower than the ones derived for 2006. The EFBC decreased 77% for both gasoline and diesel fleets, whereas the particle number EF reduction was higher for the gasoline (79%) than for the diesel (37%) fleet. Our EF are consistent with results from other on-road studies, which reinforces that the proposed methodology is suitable for EF determination and to assess the effectiveness of policies implemented to reduce vehicle exhaust emissions. However, our EF are much higher than EF simulated with traffic emission models (HBEFA and COPERT) that are based on dynamometer measurements, except for EFBC for diesel vehicles. This finding suggests that the EF from the two leading models in Europe should be revised for BC (gasoline vehicles) and particle number (all vehicles

  6. Characterizing the impact of urban emissions on regional aerosol particles; airborne measurements during the MEGAPOLI experiment

    Directory of Open Access Journals (Sweden)

    E. J. Freney

    2013-09-01

    Full Text Available The MEGAPOLI experiment took place in July 2009. The aim of this campaign was to study the aging and reactions of aerosol and gas-phase emissions in the city of Paris. Three ground-based measurement sites and several mobile platforms including instrument equipped vehicles and the ATR-42 aircraft were involved. We present here the variations in particle- and gas-phase species over the city of Paris using a combination of high-time resolution measurements aboard the ATR-42 aircraft. Particle chemical composition was measured using a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS giving detailed information of the non-refractory submicron aerosol species. The mass concentration of BC, measured by a particle absorption soot photometer (PSAP, was used as a marker to identify the urban pollution plume boundaries. Aerosol mass concentrations and composition were affected by air-mass history, with air masses that spent longest time over land having highest fractions of organic aerosol and higher total mass concentrations. The Paris plume is mainly composed of organic aerosol (OA, black carbon and nitrate aerosol, as well as high concentrations of anthropogenic gas-phase species such as toluene, benzene, and NOx. Using BC and CO as tracers for air-mass dilution, we observe the ratio of ΔOA / ΔBC and ΔOA / ΔCO increase with increasing photochemical age (−log(NOx / NOy. Plotting the equivalent ratios for the Positive Matrix Factorization (PMF resolved species (LV-OOA, SV-OOA, and HOA illustrate that the increase in OA is a result of secondary organic aerosol (SOA. Within Paris the changes in the ΔOA / ΔCO are similar to those observed during other studies in Mexico city, Mexico and in New England, USA. Using the measured VOCs species together with recent organic aerosol formation yields we predicted ~ 50% of the measured organics. These airborne measurements during the MEGAPOLI experiment show that urban emissions contribute to the

  7. Systematic trends in beta-delayed particle emitting nuclei: The case of beta-p-alpha emission from 21Mg

    CERN Document Server

    Lund, M V; Briz, J A; Cederkäll, J; Fynbo, H O U; Jensen, J H; Jonson, B; Laursen, K L; Nilsson, T; Perea, A; Pesudo, V; Riisager, K; Tengblad, O

    2015-01-01

    We have observed beta+-delayed alpha and p-alpha emission from the proton-rich nucleus 21Mg produced at the ISOLDE facility at CERN. The assignments were cross-checked with a time distribution analysis. This is the third identified case of beta-p-alpha emission. We discuss the systematic of beta-delayed particle emission decays, show that our observed decays fit naturally into the existing pattern, and argue that the patterns are to a large extent caused by odd-even effects.

  8. Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

    Directory of Open Access Journals (Sweden)

    A. Petzold

    2007-10-01

    Full Text Available Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B{&}W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by airborne aerosol transformation studies in the plume of a large container ship in the English Channel using the DLR aircraft Falcon 20 E-5. Observations from emission studies and plume studies combined with a Gaussian plume dispersion model yield a consistent picture of particle transformation processes from emission to atmospheric processing during plume expansion. Particulate matter emission indices obtained from plume measurements are 8.8±1.0×1015(kg fuel−1 by number for non-volatile particles and 174±43 mg (kg fuel−1 by mass for Black Carbon (BC. Values determined for test rig conditions between 85 and 110% engine load are of similar magnitude. For the total particle number including volatile compounds no emission index can be derived since the volatile aerosol fraction is subject to rapid transformation processes in the plume. Ship exhaust particles occur in the size range Dp<0.3 μm, showing a bi-modal structure. The combustion particle mode is centred at modal diameters of 0.05 μm for raw emissions to 0.10 μm at a plume age of 1 h. The smaller-sized volatile particle mode is centred at Dp≤0.02 μm. From the decay of ship exhaust particle number concentrations in an expanding plume, a maximum plume life time of approx. 24 h is estimated for a well-mixed marine boundary layer.

  9. Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

    Directory of Open Access Journals (Sweden)

    A. Petzold

    2008-05-01

    Full Text Available Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B&W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by airborne aerosol transformation studies in the plume of a large container ship in the English Channel using the DLR aircraft Falcon 20 E-5. Observations from emission studies and plume studies combined with a Gaussian plume dispersion model yield a consistent picture of particle transformation processes from emission to atmospheric processing during plume expansion. Particulate matter emission indices obtained from plume measurements are 8.8±1.0×1015(kg fuel−1 by number for non-volatile particles and 174±43 mg (kg fuel−1 by mass for Black Carbon (BC. Values determined for test rig conditions between 85 and 110% engine load are of similar magnitude. For the total particle number including volatile compounds no emission index can be derived since the volatile aerosol fraction is subject to rapid transformation processes in the plume. Ship exhaust particles occur in the size range Dp<0.3 μm, showing a bi-modal structure. The combustion particle mode is centred at modal diameters of 0.05 μm for raw emissions to 0.10 μm at a plume age of 1 h. The smaller-sized volatile particle mode is centred at Dp≤0.02 μm. From the decay of ship exhaust particle number concentrations in an expanding plume, a maximum plume life time of approx. 24 h is estimated for a well-mixed marine boundary layer.

  10. Dispersion of traffic-related exhaust particles near the Berlin urban motorway – estimation of fleet emission factors

    Directory of Open Access Journals (Sweden)

    W. Birmili

    2009-04-01

    Full Text Available Atmospheric particle number size distributions of airborne particles (diameter range 10–500 nm were collected over ten weeks at three sites in the vicinity of the A100 urban motorway in Berlin, Germany. The A100 carries about 180 000 vehicles on a weekday. The roadside particle distributions showed a number maximum between 20 and 60 nm clearly related to the motorway emissions. The average total number concentration at roadside was 28 000 cm−3 with a total range of 1200–168 000 cm−3. At distances of 80 and 400 m from the motorway the concentrations decreased to mean levels of 11 000 and 9000 cm−3, respectively. An obstacle-resolving dispersion model was applied to simulate the 3-D flow field and traffic tracer transport in the urban environment around the motorway. By inverse modelling, vehicle emission factors were derived that are representative of a fleet with a relative share of 6% lorry-like vehicles, and driving at a speed of 80 km h−1. Three different calculation approaches were compared, which differ in the choice of the experimental winds driving the flow simulation. The average emission factor per vehicle was 2.1 (±0.2 · 1014 km−1 for particle number and 0.077 (±0.01 · 1014 cm3 km−1 for particle volume. Regression analysis suggested that lorry-like vehicles emit 123 (±28 times more particle number than passenger car-like vehicles, and lorry-like vehicles account for about 91% of particulate number emissions on weekdays. Our work highlights the increasing applicability of 3-D flow models in urban microscale environments and their usefulness for determining traffic emission factors.

  11. Can Monkeys (Macaca mulatta) Represent Invisible Displacement?

    Science.gov (United States)

    Filion, Christine M.; Washburn, David A.; Gulledge, Jonathan P.

    1996-01-01

    Four experiments were conducted to assess whether or not rhesus macaques (Macaca mulatta) could represent the unperceived movements of a stimulus. Subjects were tested on 2 computerized tasks, HOLE (monkeys) and LASER (humans and monkeys), in which subjects needed to chase or shoot at, respectively, a moving target that either remained visible or became invisible for a portion of its path of movement. Response patterns were analyzed and compared between target-visible and target-invisible conditions. Results of Experiments 1, 2, and 3 demonstrated that the monkeys are capable of extrapolating movement. That this extrapolation involved internal representation of the target's invisible movement was suggested but not confirmed. Experiment 4, however, demonstrated that the monkeys are capable of representing the invisible displacements of a stimulus.

  12. The Pursuit of Identity in Invisible Man

    Institute of Scientific and Technical Information of China (English)

    谭佳

    2013-01-01

    Invisible Man is a representative work of black literature in America. In this novel, the writer Ralph Ellison depicts the hero’s growth experience in the white dominated society with his unique narrative techniques. As an individual in a society, the hero in this novel gradually realizes that he is an invisible man in the white dominated society and he doesn ’t have the social sta-tus which can be recognized by the white at all. To change this situation, the hero in this novel suffers many difficulties and hard-ships with an attempt to prove his existence in front of the white and the numerous black fellows and obtain his own identity as a black man which will be recognized by others. This paper tries to explore African American ’s pursuit of identity in Invisible Man by interpreting Ellison’s Invisible Man.

  13. Macroscopic Invisibility Cloaking of Visible Light

    CERN Document Server

    Chen, Xianzhong; Zhang, Jingjing; Jiang, Kyle; Pendry, John B; Zhang, Shuang

    2010-01-01

    Invisibility cloaks of light, which used to be confined to the imagination, have now been turned into a scientific reality, thanks to the enabling theoretical tools of transformation optics and conformal mapping. Inspired by those theoretical works, the experimental realisation of electromagnetic invisibility cloaks has been reported at various electromagnetic frequencies. All the invisibility cloaks demonstrated thus far, however, have relied on nano- or micro-fabricated artificial composite materials with spatially varying electromagnetic properties, which limit the size of the cloaked region to a few wavelengths. Here we report realisation of a macroscopic volumetric invisibility cloak constructed from natural birefringent crystals. The cloak operates at visible frequencies and is capable of hiding three-dimensional objects of the scale of centimetres and millimetres. Our work opens avenues for future applications with macroscopic cloaking devices.

  14. Characterization of emissions from commercial aircraft engines during the Aircraft Particle Emissions eXperiment (APEX) 1 to 3

    Science.gov (United States)

    The fine particulate matter emissions from aircraft operations at large airports located in areas of the U. S. designated as non-attainment for the National Ambient Air Quality Standard for PM-2.5 are of major environmental concern. PM emissions data for commercial aircraft engin...

  15. Simulating emission and chemical evolution of coarse sea-salt particles in the Community Multiscale Air Quality (CMAQ model

    Directory of Open Access Journals (Sweden)

    J. T. Kelly

    2010-04-01

    Full Text Available Chemical processing of sea-salt particles in coastal environments significantly impacts concentrations of particle components and gas-phase species and has implications for human exposure to particulate matter and nitrogen deposition to sensitive ecosystems. Emission of sea-salt particles from the coastal surf zone is known to be elevated compared to that from the open ocean. Despite the importance of sea-salt emissions and chemical processing, the US EPA's Community Multiscale Air Quality (CMAQ model has traditionally treated coarse sea-salt particles as chemically inert and has not accounted for enhanced surf-zone emissions. In this article, updates to CMAQ are described that enhance sea-salt emissions from the coastal surf zone and allow dynamic transfer of HNO3, H2SO4, HCl, and NH3 between coarse particles and the gas phase. Predictions of updated CMAQ models and the previous release version, CMAQv4.6, are evaluated using observations from three coastal sites during the Bay Regional Atmospheric Chemistry Experiment (BRACE in Tampa, FL in May 2002. Model updates improve predictions of NO3, SO42−, NH4+, Na+, and Cl concentrations at these sites with only a 8% increase in run time. In particular, the chemically interactive coarse particle mode dramatically improves predictions of nitrate concentration and size distributions as well as the fraction of total nitrate in the particle phase. Also, the surf-zone emission parameterization improves predictions of total sodium and chloride concentration. Results of a separate study indicate that the model updates reduce the mean absolute error of nitrate predictions at coastal CASTNET and SEARCH sites in the eastern US. Although the new model features improve performance relative to CMAQv4.6, some persistent differences exist between observations and predictions

  16. Simulating emission and chemical evolution of coarse sea-salt particles in the Community Multiscale Air Quality (CMAQ model

    Directory of Open Access Journals (Sweden)

    J. T. Kelly

    2009-12-01

    Full Text Available Chemical processing of sea-salt particles in coastal environments significantly impacts concentrations of particle components and gas-phase species and has implications for human exposure to particulate matter and nitrogen deposition to sensitive ecosystems. Emission of sea-salt particles from the coastal surf zone is known to be elevated compared to that from the open ocean. Despite the importance of sea-salt emissions and chemical processing, the US EPA's Community Multiscale Air Quality (CMAQ model has traditionally treated coarse sea-salt particles as chemically inert and has not accounted for enhanced surf-zone emissions. In this article, updates to CMAQ are described that enhance sea-salt emissions from the coastal surf zone and allow dynamic transfer of HNO3, H2SO4, HCl, and NH3 between coarse particles and the gas phase. Predictions of updated CMAQ models and the previous release version, CMAQv4.6, are evaluated using observations from three coastal sites during the Bay Regional Atmospheric Chemistry Experiment (BRACE in Tampa, FL in May 2002. Model updates improve predictions of NO3, SO42−, NH4+, Na+, and Cl concentrations at these sites with only a 8% increase in run time. In particular, the chemically interactive coarse particle mode dramatically improves predictions of nitrate concentration and size distributions as well as the fraction of total nitrate in the particle phase. Also, the surf-zone emission parameterization improves predictions of total sodium and chloride concentration. Results of a separate study indicate that the model updates reduce the mean absolute error of nitrate predictions at coastal CASTNET and SEARCH sites in the eastern US. Although the new model features improve performance relative to CMAQv4.6, some persistent differences exist between observations and predictions

  17. Simulating emission and chemical evolution of coarse sea-salt particles in the Community Multiscale Air Quality (CMAQ) model

    Science.gov (United States)

    Kelly, J. T.; Bhave, P. V.; Nolte, C. G.; Shankar, U.; Foley, K. M.

    2010-04-01

    Chemical processing of sea-salt particles in coastal environments significantly impacts concentrations of particle components and gas-phase species and has implications for human exposure to particulate matter and nitrogen deposition to sensitive ecosystems. Emission of sea-salt particles from the coastal surf zone is known to be elevated compared to that from the open ocean. Despite the importance of sea-salt emissions and chemical processing, the US EPA's Community Multiscale Air Quality (CMAQ) model has traditionally treated coarse sea-salt particles as chemically inert and has not accounted for enhanced surf-zone emissions. In this article, updates to CMAQ are described that enhance sea-salt emissions from the coastal surf zone and allow dynamic transfer of HNO3, H2SO4, HCl, and NH3 between coarse particles and the gas phase. Predictions of updated CMAQ models and the previous release version, CMAQv4.6, are evaluated using observations from three coastal sites during the Bay Regional Atmospheric Chemistry Experiment (BRACE) in Tampa, FL in May 2002. Model updates improve predictions of NO3-, SO42-, NH4+, Na+, and Cl- concentrations at these sites with only a 8% increase in run time. In particular, the chemically interactive coarse particle mode dramatically improves predictions of nitrate concentration and size distributions as well as the fraction of total nitrate in the particle phase. Also, the surf-zone emission parameterization improves predictions of total sodium and chloride concentration. Results of a separate study indicate that the model updates reduce the mean absolute error of nitrate predictions at coastal CASTNET and SEARCH sites in the eastern US. Although the new model features improve performance relative to CMAQv4.6, some persistent differences exist between observations and predictions. Modeled sodium concentration is biased low and causes under-prediction of coarse particle nitrate. Also, CMAQ over-predicts geometric mean diameter and

  18. Active Invisibility Cloaks in One Dimension

    OpenAIRE

    2015-01-01

    PHYSICAL REVIEW A 91, 063812 (2015) Active invisibility cloaks in one dimension Ali Mostafazadeh* Departments of Physics and Mathematics, Koc¸ University, Sarıyer 34450, Istanbul, Turkey (Received 19 March 2015; published 12 June 2015) We outline a general method of constructing finite-range cloaking potentials which render a given finite-range real or complex potential, v(x), unidirectionally reflectionless or invisible at a wave number, k0, of our choice.We give explici...

  19. A visible response to an invisible tattoo.

    Science.gov (United States)

    Tsang, Matthew; Marsch, Amanda; Bassett, Katrina; High, Whitney; Fitzpatrick, James; Prok, Lori

    2012-09-01

    Invisible (or blacklight) tattoos are fast becoming the trend in the world of tattoo art, and with their rise comes the onset of associated complications. Though there have been many reports of cutaneous reactions to traditional tattoo pigments, literature regarding reactions to invisible tattoos is scarce. We report the case of a 28-year-old man who presented with an inflammatory eruption of 2 months' duration confined to the area of a recently placed invisible tattoo; the eruption was diagnosed as granulomatous dermatitis to a foreign material. Under fluorescent light, a refractile foreign material was identified in the biopsy specimen, which we believe to be melamine, one of the invisible tattoo's five ingredients. Previous cases of cutaneous reactions to invisible tattoos were attributed to polymethylmethacrylate, not a component of the tattoo in this case. To our knowledge, this is the first case implicating melamine as the cause of a granulomatous tattoo reaction. Given the rising popularity of invisible tattoos, we present this case to raise awareness of the risks associated with this alternative tattoo trend.

  20. Wood burning stoves and small boilers - particle emissions and reduction initiatives; Braendeovne og smae kedler - partikelemissioner og reduktionstiltag

    Energy Technology Data Exchange (ETDEWEB)

    Illerup, J.B.; Capral Henriksen, T.; Lundhede, T. [Danmarks Miljoeundersoegelser, Aarhus Universitet, Aarhus (Denmark); Breugel, C. van; Zoellner Jensen, N. [Miljoestyrelsen, Copenhagen (Denmark)

    2007-06-15

    Pollution from burning wood in private households, and the environmental and health consequences of this is determined in practice by a complicated interaction between a number of factors, including firing habits, fuel, type of stove/boiler, chimney and location of the chimney in relation to the surroundings. This report maps out the technologies used today for burning wood in private households, how these technologies contribute to particle emissions and which technologies may potentially reduce emissions of particles from burning wood in households in Denmark. Moreover, the possible emissions reductions and the financial costs incurred by consumers from different initiatives have been estimated. This report does not deal with possible initiatives for improvement of firing habits, fuel quality and chimneys. (au)

  1. Accelerator Measurements of Magnetically Induced Radio Emission from Particle Cascades with Applications to Cosmic-Ray Air Showers.

    Science.gov (United States)

    Belov, K; Mulrey, K; Romero-Wolf, A; Wissel, S A; Zilles, A; Bechtol, K; Borch, K; Chen, P; Clem, J; Gorham, P W; Hast, C; Huege, T; Hyneman, R; Jobe, K; Kuwatani, K; Lam, J; Liu, T C; Nam, J; Naudet, C; Nichol, R J; Rauch, B F; Rotter, B; Saltzberg, D; Schoorlemmer, H; Seckel, D; Strutt, B; Vieregg, A G; Williams, C

    2016-04-08

    For 50 years, cosmic-ray air showers have been detected by their radio emission. We present the first laboratory measurements that validate electrodynamics simulations used in air shower modeling. An experiment at SLAC provides a beam test of radio-frequency (rf) radiation from charged particle cascades in the presence of a magnetic field, a model system of a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of rf emission, which are relied upon in ultrahigh-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm modern predictions that the magnetically induced emission in a dielectric forms a cone that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties.

  2. Accelerator Measurements of Magnetically Induced Radio Emission from Particle Cascades with Applications to Cosmic-Ray Air Showers

    Science.gov (United States)

    Belov, K.; Mulrey, K.; Romero-Wolf, A.; Wissel, S. A.; Zilles, A.; Bechtol, K.; Borch, K.; Chen, P.; Clem, J.; Gorham, P. W.; Hast, C.; Huege, T.; Hyneman, R.; Jobe, K.; Kuwatani, K.; Lam, J.; Liu, T. C.; Nam, J.; Naudet, C.; Nichol, R. J.; Rauch, B. F.; Rotter, B.; Saltzberg, D.; Schoorlemmer, H.; Seckel, D.; Strutt, B.; Vieregg, A. G.; Williams, C.; T-510 Collaboration

    2016-04-01

    For 50 years, cosmic-ray air showers have been detected by their radio emission. We present the first laboratory measurements that validate electrodynamics simulations used in air shower modeling. An experiment at SLAC provides a beam test of radio-frequency (rf) radiation from charged particle cascades in the presence of a magnetic field, a model system of a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of rf emission, which are relied upon in ultrahigh-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm modern predictions that the magnetically induced emission in a dielectric forms a cone that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties.

  3. Accelerator measurements of magnetically-induced radio emission from particle cascades with applications to cosmic-ray air showers

    CERN Document Server

    Belov, K; Romero-Wolf, A; Wissel, S A; Zilles, A; Bechtol, K; Borch, K; Chen, P; Clem, J; Gorham, P W; Hast, C; Huege, T; Hyneman, R; Jobe, K; Kuwatani, K; Lam, J; Liu, T; Nam, J; Naudet, C; Nichol, R; Rauch, B F; Rotter, B; Saltzberg, D; Schoorlemmer, H; Seckel, D; Strutt, B; Vieregg, A G; Williams, C

    2015-01-01

    An experiment at SLAC provides the first beam test of radio-frequency (RF) radiation from a charged particle cascade in the presence of a magnetic field (up to $\\sim$1~kG), a model system for RF emission from a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of RF emission, which are relied upon in ultra-high-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm recent predictions that the magnetically induced emission forms a beam that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties.

  4. Nitric oxide and greenhouse gases emissions following the application of different cattle slurry particle size fractions to soil

    Science.gov (United States)

    Fangueiro, David; Coutinho, João; Cabral, Fernanda; Fidalgo, Paula; Bol, Roland; Trindade, Henrique

    2012-02-01

    The application to soil of different slurry particle size fractions may lead to variable gaseous soil emissions and associated differential environmental impacts. An incubation experiment was carried out during 70 d to assess the influence on nitric oxide (NO) and greenhouse gas (GHG; i.e. nitrous oxide, carbon dioxide and methane) emissions following incorporation of 4 particle size fractions, obtained through laboratorial separation from cattle slurry, to agricultural sandy loam soil (Dystric Cambisol). The response to these applied slurry fractions (>2000 μm, 2000-500 μm, 500-100 μm, emissions (6.3 mg NO-N kg -1 dry soil) were observed from the AS treatment. The cumulated amount of NO emitted (˜1 mg NO-N kg -1 dry soil) was not significantly different between slurry fractions, thereby indicating that slurry particle size had no effect on NO emissions. The largest slurry fraction (>2000 μm) induced significantly higher N 2O emissions (1.8 mg N 2O-N kg -1 dry soil) compared to the other smaller sized fractions (1.0 mg N 2O-N kg -1 dry soil). The >2000 μm, fraction, being more than 55% of the slurry by weight, was the major contributor to daily and cumulative N 2O emissions. Hence, for N 2O, the application of WS to agricultural soil is a better option that amendment with the >2000 μm, fraction. Low CH 4 emissions (emissions were short-lived and rates returned to control levels within 3 d after the slurry application. Higher CO 2 emissions were observed in soils amended with slurry fractions when compared to application with whole slurry. Clearly, slurry separation can increase soil CO 2 emissions relative to whole slurry application. Overall, N 2O contributed 10-30% to total GHG emissions, while that of methane was negligible. The present study suggested that mechanical separation of slurry into fractions and targeted application of the finest fractions to soil is a potential suitable management tool to reduce GHG emissions. However, the largest fractions

  5. Determination of time- and size-dependent fine particle emission with varied oil heating in an experimental kitchen.

    Science.gov (United States)

    Li, Shuangde; Gao, Jiajia; He, Yiqing; Cao, Liuxu; Li, Ang; Mo, Shengpeng; Chen, Yunfa; Cao, Yaqun

    2017-01-01

    Particulate matter (PM) from cooking has caused seriously indoor air pollutant and aroused risk to human health. It is urged to get deep knowledge of their spatial-temporal distribution of source emission characteristics, especially ultrafine particles (UFPcooking oils are auto dipped water to simulate cooking fume under heating to 265°C to investigate PM emission and decay features between 0.03 and 10μm size dimension by electrical low pressure impactor (ELPI) without ventilation. Rapeseed and sunflower produced high PM2.5 around 6.1mg/m(3), in comparison with those of soybean and corn (5.87 and 4.65mg/m(3), respectively) at peak emission time between 340 and 460sec since heating oil, but with the same level of particle numbers 6-9×10(5)/cm(3). Mean values of PM1.0/PM2.5 and PM2.5/PM10 at peak emission time are around 0.51-0.66 and 0.23-0.29. After 15min naturally deposition, decay rates of PM1.0, PM2.5 and PM10 are 13.3%-29.8%, 20.1%-33.9% and 41.2%-54.7%, which manifest that PM1.0 is quite hard to decay than larger particles, PM2.5 and PM10. The majority of the particle emission locates at 43nm with the largest decay rate at 75%, and shifts to a larger size between 137 and 655nm after 15min decay. The decay rates of the particles are sensitive to the oil type. Copyright © 2016. Published by Elsevier B.V.

  6. Effects of diesel particle filter retrofits and accelerated fleet turnover on drayage truck emissions at the Port of Oakland.

    Science.gov (United States)

    Dallmann, Timothy R; Harley, Robert A; Kirchstetter, Thomas W

    2011-12-15

    Heavy-duty diesel drayage trucks have a disproportionate impact on the air quality of communities surrounding major freight-handling facilities. In an attempt to mitigate this impact, the state of California has mandated new emission control requirements for drayage trucks accessing ports and rail yards in the state beginning in 2010. This control rule prompted an accelerated diesel particle filter (DPF) retrofit and truck replacement program at the Port of Oakland. The impact of this program was evaluated by measuring emission factor distributions for diesel trucks operating at the Port of Oakland prior to and following the implementation of the emission control rule. Emission factors for black carbon (BC) and oxides of nitrogen (NO(x)) were quantified in terms of grams of pollutant emitted per kilogram of fuel burned using a carbon balance method. Concentrations of these species along with carbon dioxide were measured in the exhaust plumes of individual diesel trucks as they drove by en route to the Port. A comparison of emissions measured before and after the implementation of the truck retrofit/replacement rule shows a 54 ± 11% reduction in the fleet-average BC emission factor, accompanied by a shift to a more highly skewed emission factor distribution. Although only particulate matter mass reductions were required in the first year of the program, a significant reduction in the fleet-average NO(x) emission factor (41 ± 5%) was observed, most likely due to the replacement of older trucks with new ones.

  7. Characterization of Delayed-Particle Emission Signatures for Pyroprocessing. Part 1: ABTR Fuel Assembly.

    Energy Technology Data Exchange (ETDEWEB)

    Durkee, Jr., Joe W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-19

    A three-part study is conducted using the MCNP6 Monte Carlo radiation-transport code to calculate delayed-neutron (DN) and delayed-gamma (DG) emission signatures for nondestructive assay (NDA) metal-fuel pyroprocessing. In Part 1, MCNP6 is used to produce irradiation-induced used nuclear fuel (UNF) isotopic inventories for an Argonne National Laboratory (ANL) Advanced Burner Test Reactor (ABTR) preconceptual design fuel assembly (FA) model. The initial fuel inventory consists of uranium mixed with light-water-reactor transuranic (TRU) waste and 10 wt% zirconium (U-LWR-SFTRU-10%Zr). To facilitate understanding, parametric evaluation is done using models for 3% and 5% initial 235U a% enrichments, burnups of 5, 10, 15, 20, 30, …, 120 GWd/MTIHM, and 3-, 5-, 10-, 20-, and 30- year cooling times. Detailed delayed-particle radioisotope source terms for the irradiate FA are created using BAMF-DRT and SOURCES3A. Using simulation tallies, DG activity ratios (DGARs) are developed for 134Cs/137Cs 134Cs/154Eu, and 154Eu/137Cs markers as a function of (1) burnup and (2) actinide mass, including elemental uranium, neptunium, plutonium, americium, and curium. Spectral-integrated DN emission is also tallied. The study reveals a rich assortment of DGAR behavior as a function of DGAR type, enrichment, burnup, and cooling time. Similarly, DN emission plots show variation as a function of burnup and of actinide mass. Sensitivity of DGAR and DN signatures to initial 235U enrichment, burnup, and cooling time is evident. Comparisons of the ABTR radiation signatures and radiation signatures previously reported for a generic Westinghouse oxide-fuel assembly indicate that there are pronounced differences in the ABTR and Westinghouse oxide-fuel DN and DG signatures. These differences are largely attributable to the initial TRU inventory in the ABTR fuel. The actinide and nonactinide inventories for the

  8. A Laboratory Comparison of Emission Factors, Number Size Distributions, and Morphology of Ultrafine Particles from 11 Different Household Cookstove-Fuel Systems

    Science.gov (United States)

    Ultrafine particle (UFP) emissions and particle number size distributions (PNSD) are critical in the evaluation of air pollution impacts on human health and climate change. Residential cookstove emissions are a major source of many air pollutants; however, data on UFP number emis...

  9. Characteristics of polycyclic aromatic hydrocarbons and their gas/particle partitioning from fugitive emissions in coke plants

    Science.gov (United States)

    Mu, Ling; Peng, Lin; Liu, Xiaofeng; Song, Chongfang; Bai, Huiling; Zhang, Jianqiang; Hu, Dongmei; He, Qiusheng; Li, Fan

    2014-02-01

    Coking is one of the most important emission sources of polycyclic aromatic hydrocarbons (PAHs) in China. However, there is little information available on the emission characteristics of PAHs from fugitive emission during coking, especially on the specific processes dominating the gas-particle partitioning of PAHs. In this study, emission characteristics and gas-particle partitioning of PAHs from fugitive emission in four typical coke plants (CPs) with different scales and techniques were investigated. The average concentrations of total PAHs from fugitive emission at CP2, CP3 and CP4 (stamp charging) were 146.98, 31.82, and 35.20 μg m-3, which were 13.38-, 2.90- and 3.20-fold higher, respectively, than those at CP1 (top charging, 10.98 μg m-3). Low molecular weight PAHs with 2-3 rings made up 75.3% of the total PAHs on average, and the contributions of particulate PAH to the total BaP equivalent concentrations (BaPeq) in each plant were significantly higher than the corresponding contributions to the total PAH mass concentrations. The calculated total BaPeq concentrations varied from 0.19 to 10.86 μg m-3 with an average of 3.14 μg m-3, and more efficient measures to control fugitive emission in coke plants should be employed to prevent or reduce the health risk to workers. Absorption into organic matter dominated the gas-particle partitioning for most of the PAHs including PhA, FluA, Chr, BbF, BkF and BaP, while adsorption on elemental carbon appeared to play a dominant role for AcPy, AcP and Flu.

  10. Improved Limits on $B^{0}$ Decays to Invisible $(+gamma)$ Final States

    Energy Technology Data Exchange (ETDEWEB)

    Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Palano, A.; /Bari U. /INFN, Bari; Eigen, G.; Stugu, B.; /Bergen U.; Brown, David Nathan; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; /LBL, Berkeley /UC, Berkeley; Koch, H.; Schroeder, T.; /Ruhr U., Bochum; Asgeirsson, D.J.; Hearty, C.; Mattison, T.S.; McKenna, J.A.; So, R.Y.; /British Columbia U.; Khan, A.; /Brunel U.; Blinov, V.E.; /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /INFN, Ferrara /Frascati /Genoa U. /INFN, Genoa /Indian Inst. Tech., Guwahati /Harvard U. /Harvey Mudd Coll. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U., Comp. Sci. Dept. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /Naples U. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U.; /more authors..

    2013-11-01

    We establish improved upper limits on branching fractions for B{sup 0} decays to final states where the decay products are purely invisible (i.e., no observable final state particles) and for final states where the only visible product is a photon. Within the Standard Model, these decays have branching fractions that are below the current experimental sensitivity, but various models of physics beyond the Standard Model predict significant contributions for these channels. Using 471 million B{bar B} pairs collected at the {Upsilon} (4S) resonance by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage ring at the SLAC National Accelerator Laboratory, we establish upper limits at the 90% confidence level of 2.4 x 10{sup -5} for the branching fraction of B{sup 0} {yields} invisible and 1.7 x 10{sup -5} for the branching fraction of B{sup 0} {yields} invisible + {gamma}.

  11. Improved Limits on $B^{0}$ Decays to Invisible $(+gamma)$ Final States

    Energy Technology Data Exchange (ETDEWEB)

    Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Palano, A.; /Bari U. /INFN, Bari; Eigen, G.; Stugu, B.; /Bergen U.; Brown, David Nathan; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; /LBL, Berkeley /UC, Berkeley; Koch, H.; Schroeder, T.; /Ruhr U., Bochum; Asgeirsson, D.J.; Hearty, C.; Mattison, T.S.; McKenna, J.A.; So, R.Y.; /British Columbia U.; Khan, A.; /Brunel U.; Blinov, V.E.; /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /INFN, Ferrara /Frascati /Genoa U. /INFN, Genoa /Indian Inst. Tech., Guwahati /Harvard U. /Harvey Mudd Coll. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U., Comp. Sci. Dept. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /Naples U. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U.; /more authors..

    2013-11-01

    We establish improved upper limits on branching fractions for B{sup 0} decays to final states where the decay products are purely invisible (i.e., no observable final state particles) and for final states where the only visible product is a photon. Within the Standard Model, these decays have branching fractions that are below the current experimental sensitivity, but various models of physics beyond the Standard Model predict significant contributions for these channels. Using 471 million B{bar B} pairs collected at the {Upsilon} (4S) resonance by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage ring at the SLAC National Accelerator Laboratory, we establish upper limits at the 90% confidence level of 2.4 x 10{sup -5} for the branching fraction of B{sup 0} {yields} invisible and 1.7 x 10{sup -5} for the branching fraction of B{sup 0} {yields} invisible + {gamma}.

  12. La referencia invisible del canto.

    Directory of Open Access Journals (Sweden)

    Ricardo Sanmartín Arce

    2006-01-01

    Full Text Available El artículo sobre La referencia invisible del canto se basa en un trabajo de campo realizado en varios monasterios benedictinos y zendos españoles, así como en el estudio bibliográfico en Roma (Gregoriana, Angelicum, Vaticano y Silos de los textos en los que tanto los autores místicos, como otros creyentes confiesan sus experiencia religiosas y sus vivencias al interpretar el canto gregoriano. Se distingue el canto en directo del canto inserto en el proceso litúrgico que le es propio y se compara el ambiente creado en la vida comunitaria con otros ambientes. El canto inserto en el ritual afirma una referencia trascendente cuya comprensión exige el estudio del contexto social y cultural de la vida religiosa, así como una reflexión sobre los fundamentos vivenciales que validan ese tipo de conocimiento para los actores entrevistados o los autores estudiados.

  13. Making the Invisible Visible: Negotiating (In)Visibility and Transparency for LGBT Issues in Education

    Science.gov (United States)

    Reilly, Cole

    2007-01-01

    Historically, schooling has been a point of contention and restless agitation for many lesbian, gay, bisexual, and transgender (LGBT) individuals in North America who may feel trapped in prisons of invisibility. Traditionally, queer people's existence in educational settings has been denied or made invisible, not just physically (in school…

  14. The effects of vehicle emissions and nucleation events on vertical particle concentration profiles around urban office buildings

    Directory of Open Access Journals (Sweden)

    T. N. Quang

    2012-01-01

    Full Text Available Despite its role in determining both indoor and outdoor human exposure to anthropogenic particles, there is limited information describing vertical profiles of particle concentrations in urban environments, especially for ultrafine particles. Furthermore, the results of the few studies performed have been inconsistent. As such this study aimed to assess the influence of vehicle emissions and nucleation formation on particle concentrations (PN and PM2.5 at different heights around three urban office buildings located next to busy roads in Brisbane, Australia, and place these results in the broader context of the existing literature. Two sets of instruments were used to simultaneously measure PN size distribution, PN and PM2.5 concentrations, respectively, for up to three weeks each at three office buildings.

    The results showed that both PN and PM2.5 concentrations around building envelope were influenced by vehicle emissions and new particle formation, and that they exhibited variability across the three different office buildings. During the nucleation event, PN concentrations increased (21–46%, while PM2.5 concentrations decreased (36–52% with height at all three buildings.

    This study has shown an underappreciated role of nucleation in producing particles that can affect large numbers of people, due to the high density and occupancy of urban office buildings and the fact that the vast majority of people's time is spent indoors. These findings highlight important new information related to the previously overlooked role of particle formation in the urban atmosphere and its potential effects on selection of air intake locations and appropriate filter types when designing or upgrading mechanical ventilation systems in urban office buildings. The results also serve to better define particle behaviour and variability around building envelopes, which has implications for studies of

  15. Reduction of particle emissions from light duty vehicles and from taxies; Reduktion af partikelelemissioner fra varebiler og taxier

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Johan; Henriques, M.; Weibel, T.G. [TetraPlan A/S (Denmark)

    2006-11-03

    This project, 'Reduction of particle emissions from light duty vehicles and from taxies', analyses different strategies to reduce the particle emission, their effect for particle emissions, and the resulting cost for the society and for the companies. The project describes the EU regulation of emissions, the possibilities of reducing the emissions via special requirements in environmental zones and the Danish taxation of light duty vehicles. Further, the project includes interviews with owners of light duty vehicles and taxies and also with Danish producers of particle filters. The strategies analysed in the scenarios include: 1) Promotion of particle filters; 2) Shift from diesel to gasoline and; 3) Downsizing. The effects for particle emissions and for mortality are described. Further, the costs and benefits for the society and the cost for the companies are evaluated. The effects of the scenarios are analysed, both for initiatives implemented at a national level and for implementation in an environmental zone in the municipality of Copenhagen. The main results are that the socioeconomic benefits in the year 2012 are greater than the costs, if taxis and light duty vehicles have filters installed and if they are driving in the Copenhagen area. For light duty vehicles it is only profitable, if the prices of the filters fall to the price level that is expected in the future in the study. Further, the analysis shows that for light duty vehicles and taxies driving all over the country, the socioeconomic benefits achieved by installing particle filters are too small to cover the costs. The analysis shows that it is also profitable socio-economically to change from diesel to petrol for light duty vehicles and for taxies (except taxies driving nationally). The analysis is based on the producer prices including the general net tax level, while the specific taxes are not included. From the point of view of the companies it is not profitable to change to petrol

  16. Removal of viable bioaerosol particles with a low-efficiency HVAC filter enhanced by continuous emission of unipolar air ions.

    Science.gov (United States)

    Huang, R; Agranovski, I; Pyankov, O; Grinshpun, S

    2008-04-01

    Continuous emission of unipolar ions has been shown to improve the performance of respirators and stationary filters challenged with non-biological particles. In this study, we investigated the ion-induced enhancement effect while challenging a low-efficiency heating, ventilation and air-conditioning (HVAC) filter with viable bacterial cells, bacterial and fungal spores, and viruses. The aerosol concentration was measured in real time. Samples were also collected with a bioaerosol sampler for viable microbial analysis. The removal efficiency of the filter was determined, respectively, with and without an ion emitter. The ionization was found to significantly enhance the filter efficiency in removing viable biological particles from the airflow. For example, when challenged with viable bacteria, the filter efficiency increased as much as four- to fivefold. For viable fungal spores, the ion-induced enhancement improved the efficiency by a factor of approximately 2. When testing with virus-carrying liquid droplets, the original removal efficiency provided by the filter was rather low: 9.09 +/- 4.84%. While the ion emission increased collection about fourfold, the efficiency did not reach 75-100% observed with bacteria and fungi. These findings, together with our previously published results for non-biological particles, demonstrate the feasibility of a new approach for reducing aerosol particles in HVAC systems used for indoor air quality control. Recirculated air in HVAC systems used for indoor air quality control in buildings often contains considerable number of viable bioaerosol particles because of limited efficiency of the filters installed in these systems. In the present study, we investigated - using aerosolized bacterial cells, bacterial and fungal spores, and virus-carrying particles - a novel idea of enhancing the performance of a low-efficiency HVAC filter utilizing continuous emission of unipolar ions in the filter vicinity. The findings described in

  17. β-particle energy-summing correction for β-delayed proton emission measurements

    Science.gov (United States)

    Meisel, Z.; del Santo, M.; Crawford, H. L.; Cyburt, R. H.; Grinyer, G. F.; Langer, C.; Montes, F.; Schatz, H.; Smith, K.

    2017-02-01

    A common approach to studying β-delayed proton emission is to measure the energy of the emitted proton and corresponding nuclear recoil in a double-sided silicon-strip detector (DSSD) after implanting the β-delayed proton-emitting (βp) nucleus. However, in order to extract the proton-decay energy, the measured energy must be corrected for the additional energy implanted in the DSSD by the β-particle emitted from the βp nucleus, an effect referred to here as β-summing. We present an approach to determine an accurate correction for β-summing. Our method relies on the determination of the mean implantation depth of the βp nucleus within the DSSD by analyzing the shape of the total (proton + recoil + β) decay energy distribution shape. We validate this approach with other mean implantation depth measurement techniques that take advantage of energy deposition within DSSDs upstream and downstream of the implantation DSSD.

  18. Particle-Induced X-Ray Emission (PIXE) Of Silicate Coatings On High Impact Resistance Polycarbonates

    Science.gov (United States)

    Xing, Qian; Hart, M. A.; Culbertson, R. J.; Bradley, J. D.; Herbots, N.; Wilkens, Barry J.; Sell, David A.; Watson, Clarizza Fiel

    2011-06-01

    Particle-Induced X-ray Emission (PIXE) analysis was employed to characterize hydroxypropyl methylcellulose (HPMC) C32H60O19 polymer film via areal density measurement on silicon-based substrates utilizing the differential PIXE concept, and compared with Rutherford backscattering spectrometry (RBS) results. It is demonstrated in this paper that PIXE and RBS measurements both yield comparable results for areal densities ranging from 1018 atom/cm2 to several 1019 atom/cm2. A collection of techniques including PIXE, RBS, tapping mode atomic force microscopy (TMAFM), and contact angle analysis were used to compute surface free energy, analyze surface topography and roughness parameters, determine surface composition and areal density, and to predict the water affinity and condensation behaviors of silicates and other compounds used for high impact resistance vision ware coatings. The visor surface under study is slightly hydrophilic, with root mean square of surface roughness on the order of one nm, and surface wavelength between 200 nm and 300 nm. Water condensation can be controlled on such surfaces via polymers adsorption. HPMC polymer areal density measurement supports the analysis of the surface water affinity and topography and the subsequent control of condensation behavior. HPMC film between 1018 atom/cm2 and 1019 atom/cm2 was found to effectively alter the water condensation pattern and prevents fogging by forming a wetting layer during condensation.

  19. Association of the mutagenicity of airborne particles with the direct emission from combustion processes investigated in Osaka, Japan

    Science.gov (United States)

    Kameda, Takayuki; Sanukida, Satoshi; Inazu, Koji; Hisamatsu, Yoshiharu; Maeda, Yasuaki; Takenaka, Norimichi; Bandow, Hiroshi

    The association of the direct-acting mutagenicity of soluble organic fraction of airborne particles toward Salmonella typhimurium YG1024 strain with the direct emission was investigated at a roadside and at a residential area in Osaka, Japan. The direct-acting mutagenicity was evaluated as mutagenic activity per unit volume of ambient air (rev m -3) and/or that per airborne particulate weight collected on a filter (rev mg -1). The annual or diurnal changes of the mutagenicity of airborne particles at the residential site showed similar patterns to those of some gaseous pollutants such as NO 2 and SO 2, which were emitted from combustion processes. This result indicates that the mutagenicity is mainly attributable to the primary emissions. From the analysis of the relationship between the wind sector and the mutagenic intensity, rev m -3 and rev mg -1 values were strongly affected by the emissions from the fixed sources and from the mobile sources, respectively. The rev m -3 value and concentration of 1-nitropyrene (1-NP) in unit per m 3 at the roadside were a factor of 2.6 and 2.8 higher than those at the residential site, respectively, but the rev mg -1 value and concentration of 1-NP in unit per mg at the roadside were substantially comparable to those at the residential area. These observations suggest that the characteristics of the airborne particles can be attributed to the automotive emissions even at the suburban area.

  20. The future of airborne sulfur-containing particles in the absence of fossil fuel sulfur dioxide emissions.

    Science.gov (United States)

    Perraud, Véronique; Horne, Jeremy R; Martinez, Andrew S; Kalinowski, Jaroslaw; Meinardi, Simone; Dawson, Matthew L; Wingen, Lisa M; Dabdub, Donald; Blake, Donald R; Gerber, R Benny; Finlayson-Pitts, Barbara J

    2015-11-03

    Sulfuric acid (H2SO4), formed from oxidation of sulfur dioxide (SO2) emitted during fossil fuel combustion, is a major precursor of new airborne particles, which have well-documented detrimental effects on health, air quality, and climate. Another precursor is methanesulfonic acid (MSA), produced simultaneously with SO2 during the atmospheric oxidation of organosulfur compounds (OSCs), such as dimethyl sulfide. In the present work, a multidisciplinary approach is used to examine how contributions of H2SO4 and MSA to particle formation will change in a large coastal urban area as anthropogenic fossil fuel emissions of SO2 decline. The 3-dimensional University of California Irvine-California Institute of Technology airshed model is used to compare atmospheric concentrations of gas phase MSA, H2SO4, and SO2 under current emissions of fossil fuel-associated SO2 and a best-case futuristic scenario with zero fossil fuel sulfur emissions. Model additions include results from (i) quantum chemical calculations that clarify the previously uncertain gas phase mechanism of formation of MSA and (ii) a combination of published and experimental estimates of OSC emissions, such as those from marine, agricultural, and urban processes, which include pet waste and human breath. Results show that in the zero anthropogenic SO2 emissions case, particle formation potential from H2SO4 will drop by about two orders of magnitude compared with the current situation. However, particles will continue to be generated from the oxidation of natural and anthropogenic sources of OSCs, with contributions from MSA and H2SO4 of a similar order of magnitude. This could be particularly important in agricultural areas where there are significant sources of OSCs.

  1. Optical and Physical Properties from Primary On-Road Vehicle ParticleEmissions And Their Implications for Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Strawa, A.W.; Kirchstetter, T.W.; Hallar, A.G.; Ban-Weiss, G.A.; McLaughlin, J.P.; Harley, R.A.; Lunden, M.M.

    2009-01-23

    During the summers of 2004 and 2006, extinction and scattering coefficients of particle emissions inside a San Francisco Bay Area roadway tunnel were measured using a combined cavity ring-down and nephelometer instrument. Particle size distributions and humidification were also measured, as well as several gas phase species. Vehicles in the tunnel traveled up a 4% grade at a speed of approximately 60 km h{sup -1}. The traffic situation in the tunnel allows the apportionment of emission factors between light duty gasoline vehicles and diesel trucks. Cross-section emission factors for optical properties were determined for the apportioned vehicles to be consistent with gas phase and particulate matter emission factors. The absorption emission factor (the absorption cross-section per mass of fuel burned) for diesel trucks (4.4 {+-} 0.79 m{sup 2} kg{sup -1}) was 22 times larger than for light-duty gasoline vehicles (0.20 {+-} 0.05 m{sup 2} kg{sup -1}). The single scattering albedo of particles - which represents the fraction of incident light that is scattered as opposed to absorbed - was 0.2 for diesel trucks and 0.3 for light duty gasoline vehicles. These facts indicate that particulate matter from motor vehicles exerts a positive (i.e., warming) radiative climate forcing. Average particulate mass absorption efficiencies for diesel trucks and light duty gasoline vehicles were 3.14 {+-} 0.88 m{sup 2} g{sub PM}{sup -1} and 2.9 {+-} 1.07 m{sup 2} g{sub PM}{sup -1}, respectively. Particle size distributions and optical properties were insensitive to increases in relative humidity to values in excess of 90%, reinforcing previous findings that freshly emitted motor vehicle particulate matter is hydrophobic.

  2. A comparison of positron emission particle tracking (PEPT) methods for analysis of a tube-in-shell heat exchanger

    Science.gov (United States)

    Wiggins, Cody; Patel, Nitant; Ruggles, Arthur

    2016-03-01

    A positron emission particle tracking (PEPT) study of a stainless steel tube-in-shell heat exchanger is performed. Studies are performed using two different energy window settings. A new multiple particle tracking technique is introduced and used in this analysis. Results are compared to those obtained with previously established multiple particle tracking technique. Both techniques are found to be capable of flow imaging through opaque surfaces. No significant difference is observed between energy window settings using either method. Results from both methods are found to be qualitatively similar; however, it is observed that the new method exhibits consistently lower measurement uncertainty across the field of view of the scanner and is robust against the adverse effects of stationary particles in the flow field.

  3. Biomass burning emissions of trace gases and particles in marine air at Cape Grim, Tasmania, 41° S

    Directory of Open Access Journals (Sweden)

    S. J. Lawson

    2015-07-01

    Full Text Available Biomass burning (BB plumes were measured at the Cape Grim Baseline Air Pollution Station during the 2006 Precursors to Particles campaign, when emissions from a fire on nearby Robbins Island impacted the station. Measurements made included non methane organic compounds (NMOCs (PTR-MS, particle number size distribution, condensation nuclei (CN > 3 nm, black carbon (BC concentration, cloud condensation nuclei (CCN number, ozone (O3, methane (CH4, carbon monixide (CO, hydrogen (H2, carbon dioxide (CO2, nitrous oxide (N2O, halocarbons and meteorology. During the first plume strike event (BB1, a four hour enhancement of CO (max ~ 2100 ppb, BC (~ 1400 ng m−3 and particles > 3 nm (~ 13 000 cm−3 with dominant particle mode of 120 nm were observed overnight. Dilution of the plume resulted in a drop in the dominant particle mode to 50 nm, and then growth to 80 nm over 5 h. This was accompanied by an increase in O3, suggesting that photochemical processing of air and condensation of low volatility oxidation products may be driving particle growth. The ability of particles > 80 nm (CN80 to act as CCN at 0.5 % supersaturation was investigated. The ΔCCN / ΔCN80 ratio was lowest during the fresh BB plume (56 %, higher during the particle growth event (77 % and higher still (104 % in background marine air. Particle size distributions indicate that changes to particle chemical composition, rather than particle size, are driving these changes. Hourly average CCN during both BB events were between 2000–5000 CCN cm−3, which were enhanced above typical background levels by a factor of 6–34, highlighting the dramatic impact BB plumes can have on CCN number in clean marine regions. During the 29 h of the second plume strike event (BB2 CO, BC and a range of NMOCs including acetonitrile and hydrogen cyanide (HCN were clearly enhanced and some enhancements in O3 were observed (ΔO3 / ΔCO 0.001–0.074. A shortlived increase in NMOCs by a factor of 10

  4. Biomass burning emissions of trace gases and particles in marine air at Cape Grim, Tasmania, 41° S

    Science.gov (United States)

    Lawson, S. J.; Keywood, M. D.; Galbally, I. E.; Gras, J. L.; Cainey, J. M.; Cope, M. E.; Krummel, P. B.; Fraser, P. J.; Steele, L. P.; Bentley, S. T.; Meyer, C. P.; Ristovski, Z.; Goldstein, A. H.

    2015-07-01

    Biomass burning (BB) plumes were measured at the Cape Grim Baseline Air Pollution Station during the 2006 Precursors to Particles campaign, when emissions from a fire on nearby Robbins Island impacted the station. Measurements made included non methane organic compounds (NMOCs) (PTR-MS), particle number size distribution, condensation nuclei (CN) > 3 nm, black carbon (BC) concentration, cloud condensation nuclei (CCN) number, ozone (O3), methane (CH4), carbon monixide (CO), hydrogen (H2), carbon dioxide (CO2), nitrous oxide (N2O), halocarbons and meteorology. During the first plume strike event (BB1), a four hour enhancement of CO (max ~ 2100 ppb), BC (~ 1400 ng m-3) and particles > 3 nm (~ 13 000 cm-3) with dominant particle mode of 120 nm were observed overnight. Dilution of the plume resulted in a drop in the dominant particle mode to 50 nm, and then growth to 80 nm over 5 h. This was accompanied by an increase in O3, suggesting that photochemical processing of air and condensation of low volatility oxidation products may be driving particle growth. The ability of particles > 80 nm (CN80) to act as CCN at 0.5 % supersaturation was investigated. The ΔCCN / ΔCN80 ratio was lowest during the fresh BB plume (56 %), higher during the particle growth event (77 %) and higher still (104 %) in background marine air. Particle size distributions indicate that changes to particle chemical composition, rather than particle size, are driving these changes. Hourly average CCN during both BB events were between 2000-5000 CCN cm-3, which were enhanced above typical background levels by a factor of 6-34, highlighting the dramatic impact BB plumes can have on CCN number in clean marine regions. During the 29 h of the second plume strike event (BB2) CO, BC and a range of NMOCs including acetonitrile and hydrogen cyanide (HCN) were clearly enhanced and some enhancements in O3 were observed (ΔO3 / ΔCO 0.001-0.074). A shortlived increase in NMOCs by a factor of 10 corresponded

  5. MIRO Observations of Millimeter-wave Emission from Large Dust Particles in the Coma of 67P/Churyumov-Gerasimenko

    Science.gov (United States)

    Schloerb, F. Peter; Gulkis, Samuel; Biver, Nicolas; von Allmen, Paul; Beaudin, Gerard; Bockelee-Morvan, Dominique; Choukroun, Mathieu; Crovisier, Jacques; Davidsson, Bjorn; Encrenaz, Pierre; Encrenaz, Therese A.; Frerking, Margaret; Hartogh, Paul; Ip, Wing-Huen; Janssen, Michael A.; Jarchow, Christopher; Kareta, Teddy; Lellouch, Emmanuel; Leyrat, Cedric; Rezac, Ladislav; Spilker, Thomas R.

    2016-10-01

    We present observations of dust emission from comet 67P/Churyumov-Gerasimenko obtained by the Microwave Instrument for the Rosetta Orbiter (MIRO). MIRO is a millimeter-wave instrument with two continuum channels at wavelengths of 0.53 mm and 1.59 mm. The instrument has a 30cm-diameter antenna which provides resolution of about 217m and 690m at the respective wavelengths for a spacecraft-comet distance of 100km. During the months around the August 2015 perihelion of comet 67P, a small continuum emission excess was observed above the sunlit limb of the comet. The excess emission extends many beam widths off the dayside limb and is a persistent feature for months of observations. No excess above the noise limit of the instrument is observed above the nightside limb, and given the known strong day-night asymmetry of gas production from the nucleus, we interpret the observed continuum excess on the day side to result from thermal emission from dust. Typical antenna temperatures of the emission over the day side at a distance of 4 km from the center of the nucleus (approximately 2 km above the surface) are approximately 1K in both the submillimeter-wave (0.53 mm) and millimeter-wave (1.59 mm) channels, corresponding to likely dust column densities of ~0.1 kg m-2. The typical relative brightness of the 0.53 mm emission to the 1.59 mm emission is approximately 1.2. This result is most consistent with particle size distributions which extend up to radii of at least several centimeters and/or flatter particle size distributions than those often attributed to cometary dust. Maps of the emission show that the column density of dust decreases with distance from the nucleus following a power law with b-1.6 - b-2.0, where b is the impact parameter of the beam with respect to the nucleus. Models of dust outflow, in which particles are accelerated by the drag force of the outflowing gas, predict a column density falloff according to b-1.2. We find that to achieve the observed

  6. Invisible the dangerous allure of the unseen

    CERN Document Server

    Ball, Philip

    2015-01-01

    If you could be invisible, what would you do? The chances are that it would have something to do with power, wealth or sex. Perhaps all three. But there's no need to feel guilty. Impulses like these have always been at the heart of our fascination with invisibility: it points to realms beyond our senses, serves as a receptacle for fears and dreams, and hints at worlds where other rules apply. Invisibility is a mighty power and a terrible curse, a sexual promise, a spiritual condition. This is a history of humanity's turbulent relationship with the invisible. It takes on the myths and morals of Plato, the occult obsessions of the Middle Ages, the trickeries and illusions of stage magic, the auras and ethers of Victorian physics, military strategies to camouflage armies and ships and the discovery of invisibly small worlds. From the medieval to the cutting-edge, fairy tales to telecommunications, from beliefs about the supernatural to the discovery of dark energy, Philip Ball reveals the universe of the invi...

  7. Proton-induced composite particle emission in inclusive reactions in the range of 100 to 200 MeV

    Directory of Open Access Journals (Sweden)

    Cowley A.A.

    2012-12-01

    Full Text Available Nucleon-induced inclusive reactions at incident energies in the 100 to 200 MeV range, in which light composite particles are emitted, are of special interest. For emission of α-particles into the continuum, it appears that the yield is enhanced towards lower outgoing energies of the ejectile compared with the value predicted by a multistep model. We postulate that a simple reaction mechanism, such as sequential decay from inelastic excitation, should be investigated more carefully as a possible explanation of the observed phenomenon. The motivation for this is that the suggested mechanism is a process which is observed in several (p, pα knockout studies.

  8. Pb-210 and fly ash particles in ombrotrophic peat bogs as indicators of industrial emissions.

    Science.gov (United States)

    Vaasma, Taavi; Karu, Helen; Kiisk, Madis; Pensa, Margus; Isakar, Kadri; Realo, Enn; Alliksaar, Tiiu; Tkaczyk, Alan Henry

    2017-08-01

    Peat cores were collected from a Sphagnum-dominated Selisoo bog, which is located about 40 km from the large oil shale-fired power plants (PPs) in Estonia. These PPs have been operational from the 1960's and had the largest negative impact on the surrounding environment during the 1970's and 1980's. Nearby ombrotrophic peatlands are good indicators of atmospheric pollution due to their properties of effectively adsorbing mineral matter and pollutants. Collected peat cores (S1 and S2) from Selisoo peat bog were sliced into 1 cm thick layers and measured gamma spectrometrically. In addition, spherical fly ash particles (SFAP) originating from the combustion of the PPs were counted. The maximum concentrations (particles per cm(3)) of the SFAP remained between 7 and 12 cm for core S1 and between 11 and 17 cm for core S2. The concentration profiles of the SFAP reflect the combustion and emission history of the PPs. Pb-210 activity concentrations have the maximum values up to 500 Bq kg(-1) and 413 Bq m(-2) for S1 and for the S2 the values are 441 Bq kg(-1) and 535 Bq m(-2) (dry weight). The unsupported (210)Pb inventory is around 4250 Bq m(-2). This represents a (210)Pb deposition flux of 133 Bq m(-2) y(-1). The estimated (210)Pb deposition via fly ash from the PPs at Selisoo area remains between 0.2 and 2.2 Bq m(-2) y(-1). Considering the annual (210)Pb deposition from the atmosphere (with a precipitation rate of 600 mm y(-1)) between 92 and 133 Bq m(-2), which is regarded as the natural background value, we show that the radiological burden due to the power plants at these distances is negligible. As the peat cores exhibit noticeable differences from each other (in terms of radionuclide concentration distribution), the SFAP can provide a good additional parameter to improve the validity of results obtained only from radiometric methods in the chronological studies. SFAP can also act as a possible tool to estimate the radionuclide deposition rate

  9. A new setup for the investigation of swift heavy ion induced particle emission and surface modifications

    Energy Technology Data Exchange (ETDEWEB)

    Meinerzhagen, F.; Breuer, L.; Bukowska, H.; Herder, M.; Schleberger, M.; Wucher, A. [Fakultät für Physik, Universität Duisburg-Essen and Cenide, 47057 Duisburg (Germany); Bender, M.; Severin, D. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Lebius, H. [CIMAP (CEA-CNRS-ENSICAEN-UCN), 14070 Caen Cedex 5 (France)

    2016-01-15

    The irradiation with fast ions with kinetic energies of >10 MeV leads to the deposition of a high amount of energy along their trajectory (up to several ten keV/nm). The energy is mainly transferred to the electronic subsystem and induces different secondary processes of excitations, which result in significant material modifications. A new setup to study these ion induced effects on surfaces will be described in this paper. The setup combines a variable irradiation chamber with different techniques of surface characterizations like scanning probe microscopy, time-of-flight secondary ion, and neutral mass spectrometry, as well as low energy electron diffraction under ultra high vacuum conditions, and is mounted at a beamline of the universal linear accelerator (UNILAC) of the GSI facility in Darmstadt, Germany. Here, samples can be irradiated with high-energy ions with a total kinetic energy up to several GeVs under different angles of incidence. Our setup enables the preparation and in situ analysis of different types of sample systems ranging from metals to insulators. Time-of-flight secondary ion mass spectrometry enables us to study the chemical composition of the surface, while scanning probe microscopy allows a detailed view into the local electrical and morphological conditions of the sample surface down to atomic scales. With the new setup, particle emission during irradiation as well as persistent modifications of the surface after irradiation can thus be studied. We present first data obtained with the new setup, including a novel measuring protocol for time-of-flight mass spectrometry with the GSI UNILAC accelerator.

  10. A new setup for the investigation of swift heavy ion induced particle emission and surface modifications

    Science.gov (United States)

    Meinerzhagen, F.; Breuer, L.; Bukowska, H.; Bender, M.; Severin, D.; Herder, M.; Lebius, H.; Schleberger, M.; Wucher, A.

    2016-01-01

    The irradiation with fast ions with kinetic energies of >10 MeV leads to the deposition of a high amount of energy along their trajectory (up to several ten keV/nm). The energy is mainly transferred to the electronic subsystem and induces different secondary processes of excitations, which result in significant material modifications. A new setup to study these ion induced effects on surfaces will be described in this paper. The setup combines a variable irradiation chamber with different techniques of surface characterizations like scanning probe microscopy, time-of-flight secondary ion, and neutral mass spectrometry, as well as low energy electron diffraction under ultra high vacuum conditions, and is mounted at a beamline of the universal linear accelerator (UNILAC) of the GSI facility in Darmstadt, Germany. Here, samples can be irradiated with high-energy ions with a total kinetic energy up to several GeVs under different angles of incidence. Our setup enables the preparation and in situ analysis of different types of sample systems ranging from metals to insulators. Time-of-flight secondary ion mass spectrometry enables us to study the chemical composition of the surface, while scanning probe microscopy allows a detailed view into the local electrical and morphological conditions of the sample surface down to atomic scales. With the new setup, particle emission during irradiation as well as persistent modifications of the surface after irradiation can thus be studied. We present first data obtained with the new setup, including a novel measuring protocol for time-of-flight mass spectrometry with the GSI UNILAC accelerator.

  11. Quantitative autoradiography of alpha particle emission in geo-materials using the Beaver™ system

    Science.gov (United States)

    Sardini, Paul; Angileri, Axel; Descostes, Michael; Duval, Samuel; Oger, Tugdual; Patrier, Patricia; Rividi, Nicolas; Siitari-Kauppi, Marja; Toubon, Hervé; Donnard, Jérôme

    2016-10-01

    In rocks or artificial geo-materials, radioactive isotopes emitting alpha particles are dispersed according to the mineralogy. At hand specimen scale, the achievement of quantitative chemical mapping of these isotopes takes on a specific importance. Knowledge of the distribution of the uranium and thorium series radionuclides is of prime interest to several disciplines, from the geochemistry of uranium deposits, to the dispersion of uranium mill tailings in the biosphere. The disequilibrium of these disintegration chains is also commonly used for dating. However, some prime importance isotopes, such as 226Ra, are complicated to localize in geo-materials. Because of its high specific activity, 226Ra is found in very low concentrations ( ppq), preventing its accurate localization in rock forming minerals. This paper formulates a quantitative answer to the following question: at hand specimen scale, how can alpha emitters in geo-materials be mapped quantitatively? In this study, we tested a new digital autoradiographic method (called the Beaver™) based on a Micro Patterned Gaseous Detector (MPGD) in order to quantitatively map alpha emission at the centimeter scale rock section. Firstly, for two thin sections containing U-bearing minerals at secular equilibrium, we compared the experimental and theoretical alpha count rates, measured by the Beaver™ and calculated from the uranium content, respectively. We found that they are very similar. Secondly, for a set of eight homemade standards made up of a mixture of inactive sand and low-radioactivity mud, we compared the count rates obtained by the Beaver™ and by an alpha spectrometer. The results indicate (i) a linearity between both count rates, and (ii) that the count obtained by the Beaver™ can be estimated from the count obtained by the alpha spectrometry using a factor of 0.82.

  12. Particle emissions from ventilation equipment: health hazards, measurement and product development; Ilmanvaihtolaitteiden hiukkaspaeaestoet: terveyshaitat, mittaaminen ja tuotekehitys - ILMI

    Energy Technology Data Exchange (ETDEWEB)

    Tossavainen, A.; Paananen, H.; Riala, R.; Tuomi, T.; Voutilainen, R. [Finnish Institute of Occupational Health, Helsinki (Finland); Heimonen, I.; Kovanen, K. [VTT Building and Transport, Espoo (Finland)

    2004-07-01

    The project will develop the design, structure and materials of ventilation equipment for the improvement of indoor air quality in office-type buildings. Particle emissions from commercial products are measured by laboratory tests. In ten buildings, the dust and fibre levels will be surveyed in relation to the design and operation of the ventilation equipment. Direct-reading particle counters and filter sampling method combined with optical and electron microscopy analyses are the main methods in these surveys. Nasal lavage is used for the estimation of inhalation exposure to coarse man-made mineral fibres. Technical criteria will be drafted for the design and testing of fibre emissions from various ventilation equipment. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-02-01

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

  14. Invisibility Cloak Printed on a Photonic Chip

    CERN Document Server

    Feng, Zhen; Zhao, Yu-Xi; Gao, Jun; Qiao, Lu-Feng; Yang, Ai-Lin; Lin, Xiao-Feng; Jin, Xian-Min

    2016-01-01

    Invisibility cloak capable of hiding an object can be achieved by properly manipulating electromagnetic field. Such a remarkable ability has been shown in transformation and ray optics. Alternatively, it may be realistic to create a spatial cloak by means of confining electromagnetic field in three-dimensional arrayed waveguides and introducing appropriate collective curvature surrounding an object. We realize the artificial structure in borosilicate by femtosecond laser direct writing, where we prototype up to 5000 waveguides to conceal millimeter-scale volume. We characterize the performance of the cloak by normalized cross correlation, tomography analysis and continuous three-dimensional viewing angle scan. Our results show invisibility cloak can be achieved in waveguide optics. Furthermore, directly printed invisibility cloak on a photonic chip may enable controllable study and novel applications in classical and quantum integrated photonics, such as invisualising a coupling or swapping operation with on-...

  15. Invisibility Cloak Printed on a Photonic Chip

    Science.gov (United States)

    Feng, Zhen; Wu, Bing-Hong; Zhao, Yu-Xi; Gao, Jun; Qiao, Lu-Feng; Yang, Ai-Lin; Lin, Xiao-Feng; Jin, Xian-Min

    2016-01-01

    Invisibility cloak capable of hiding an object can be achieved by properly manipulating electromagnetic field. Such a remarkable ability has been shown in transformation and ray optics. Alternatively, it may be realistic to create a spatial cloak by means of confining electromagnetic field in three-dimensional arrayed waveguides and introducing appropriate collective curvature surrounding an object. We realize the artificial structure in borosilicate by femtosecond laser direct writing, where we prototype up to 5,000 waveguides to conceal millimeter-scale volume. We characterize the performance of the cloak by normalized cross correlation, tomography analysis and continuous three-dimensional viewing angle scan. Our results show invisibility cloak can be achieved in waveguide optics. Furthermore, directly printed invisibility cloak on a photonic chip may enable controllable study and novel applications in classical and quantum integrated photonics, such as invisualising a coupling or swapping operation with on-chip circuits of their own. PMID:27329510

  16. Cuidados invisibles: ¿son suficientemente reconocidos?

    Directory of Open Access Journals (Sweden)

    Rosanna de la Rosa Eduardo

    Full Text Available Los cuidados invisibles son un elemento central y fundamental de la práctica de la Enfermería y son la base de su identidad profesional. La Enfermería ha sufrido un importante y positivo proceso de profesionalización en los últimos 150 años, sin embargo, los cuidados invisibles siguen siendo poco reconocidos, a pesar de su importancia en la recuperación y en la calidad de vida de los usuarios. En este trabajo se analizan brevemente las grandes transformaciones sociales actuales que obligan a replantearse la necesidad de visibilizar los cuidados invisibles, se plantean interrogantes clave para abordar esta discusión y se proponen una serie de acciones concretas para avanzar en este reconocimiento.

  17. Applications of Beta Particle Detection for Synthesis and Usage of Radiotracers Developed for Positron Emission Tomography

    Science.gov (United States)

    Dooraghi, Alex Abreu

    Positron Emission Tomography (PET) is a noninvasive molecular imaging tool that requires the use of a radioactive compound or radiotracer which targets a molecular pathway of interest. We have developed and employed three beta particle radiation detection systems to advance PET. Specifically, the goals of these systems are to: 1. Automate dispensing of solutions containing a positron emitting isotope. 2. Monitor radioactivity on-chip during synthesis of a positron emitting radiotracer. 3. Assay cellular uptake on-chip of a positron emitting radiotracer. Automated protocols for measuring and dispensing solutions containing radioisotopes are essential not only for providing an optimum environment for radiation workers, but also to ensure a quantitatively accurate workflow. For the first project, we describe the development and performance of a system for automated radioactivity distribution of beta particle emitting radioisotopes such as fluorine-18 (F-18). Key to the system is a radiation detector in-line with a peristaltic pump. The system demonstrates volume accuracy within 5 % for volumes of 20 muL or greater. When considering volumes of 20 muL or greater, delivered radioactivity is in agreement with the requested radioactivity as measured with the dose calibrator. The integration of the detector and pump leads to a flexible system that can accurately dispense solutions containing F-18 in radioactivity concentrations directly produced from a cyclotron (~ 0.1-1 mCi/muL), to low activity concentrations intended for preclinical mouse scans (~ 1-10 muCi/muL), and anywhere in between. Electrowetting on dielectric (EWOD) is an attractive microfluidic platform for batch synthesis of PET radiotracers. Visualization of radioisotopes on-chip is critical for synthesis optimization and technological development. For the second project, we describe the development and performance of a Cerenkov/real-time imaging system for PET radiotracer synthesis on EWOD. We also investigate

  18. Particle number concentration near road traffic in Amsterdam (the Netherlands): Comparison of standard and real-world emission factors

    Science.gov (United States)

    Keuken, M. P.; Moerman, M.; Voogt, M.; Zandveld, P.; Verhagen, H.; Stelwagen, U.; Jonge de, D.

    2016-05-01

    In this study, NOx and particle number concentration (PNC) at an urban background and a traffic location were measured in the city of Amsterdam (the Netherlands). Modelled and measured contributions to NOx and PNC at the traffic location were used to derive real-world PN emission factors for average urban road traffic. The results for NOx were applied to validate our approach. The real-world PN emission factors (#.km-1) were 2.9E+14 (urban road) and 3E+14 (motorway). These values were at least a factor eight higher than dynamometer-based PN emission factors from COPERT 4 and HBEFA databases. The real-world PN emission factors were used to model the contribution to PNC near road traffic in 2014. This was two to three times higher than the PNC urban background along urban roads over 20,000 vehicles per day and near motorways. The discrepancy between dynamometer-based and real-world emission factors demonstrates the need for more PNC observations to assess actual PN emissions from road traffic.

  19. Comment visualiser l'invisible?

    CERN Multimedia

    Develay, Dominique

    2007-01-01

    In the big hadron collider, LHC, nearly finished, particle will be accelerated to make collisions, with the aim to re-create the conditions of the birth of Universe, some seconds after the Big Bang. (1 page)

  20. Invisible excess of sense in social interaction.

    Science.gov (United States)

    Koubová, Alice

    2014-01-01

    The question of visibility and invisibility in social understanding is examined here. First, the phenomenological account of expressive phenomena and key ideas of the participatory sense-making theory are presented with regard to the issue of visibility. These accounts plead for the principal visibility of agents in interaction. Although participatory sense-making does not completely rule out the existence of opacity and invisible aspects of agents in interaction, it assumes the capacity of agents to integrate disruptions, opacity and misunderstandings in mutual modulation. Invisibility is classified as the dialectical counterpart of visibility, i.e., as a lack of sense whereby the dynamics of perpetual asking, of coping with each other and of improvements in interpretation are brought into play. By means of empirical exemplification this article aims at demonstrating aspects of invisibility in social interaction which complement the enactive interpretation. Without falling back into Cartesianism, it shows through dramaturgical analysis of a practice called "(Inter)acting with the inner partner" that social interaction includes elements of opacity and invisibility whose role is performative. This means that opacity is neither an obstacle to be overcome with more precise understanding nor a lack of meaning, but rather an excess of sense, a "hiddenness" of something real that has an "active power" (Merleau-Ponty). In this way it contributes to on-going social understanding as a hidden potentiality that naturally enriches, amplifies and in part constitutes human participation in social interactions. It is also shown here that this invisible excess of sense already functions on the level of self-relationship due to the essential self-opacity and self-alterity of each agent of social interaction. The analysis consequently raises two issues: the question of the enactive ethical stance toward the alterity of the other and the question of the autonomy of the self

  1. Effects of a combined Diesel particle filter-DeNOx system (DPN) on reactive nitrogen compounds emissions: a parameter study.

    Science.gov (United States)

    Heeb, Norbert V; Haag, Regula; Seiler, Cornelia; Schmid, Peter; Zennegg, Markus; Wichser, Adrian; Ulrich, Andrea; Honegger, Peter; Zeyer, Kerstin; Emmenegger, Lukas; Zimmerli, Yan; Czerwinski, Jan; Kasper, Markus; Mayer, Andreas

    2012-12-18

    The impact of a combined diesel particle filter-deNO(x) system (DPN) on emissions of reactive nitrogen compounds (RNCs) was studied varying the urea feed factor (α), temperature, and residence time, which are key parameters of the deNO(x) process. The DPN consisted of a platinum-coated cordierite filter and a vanadia-based deNO(x) catalyst supporting selective catalytic reduction (SCR) chemistry. Ammonia (NH₃) is produced in situ from thermolysis of urea and hydrolysis of isocyanic acid (HNCO). HNCO and NH₃ are both toxic and highly reactive intermediates. The deNO(x) system was only part-time active in the ISO8178/4 C1cycle. Urea injection was stopped and restarted twice. Mean NO and NO₂ conversion efficiencies were 80%, 95%, 97% and 43%, 87%, 99%, respectively, for α = 0.8, 1.0, and 1.2. HNCO emissions increased from 0.028 g/h engine-out to 0.18, 0.25, and 0.26 g/h at α = 0.8, 1.0, and 1.2, whereas NH₃ emissions increased from <0.045 to 0.12, 1.82, and 12.8 g/h with maxima at highest temperatures and shortest residence times. Most HNCO is released at intermediate residence times (0.2-0.3 s) and temperatures (300-400 °C). Total RNC efficiencies are highest at α = 1.0, when comparable amounts of reduced and oxidized compounds are released. The DPN represents the most advanced system studied so far under the VERT protocol achieving high conversion efficiencies for particles, NO, NO₂, CO, and hydrocarbons. However, we observed a trade-off between deNO(x) efficiency and secondary emissions. Therefore, it is important to adopt such DPN technology to specific application conditions to take advantage of reduced NO(x) and particle emissions while avoiding NH₃ and HNCO slip.

  2. Size-resolved aerosol emission factors and new particle formation/growth activity occurring in Mexico City during the MILAGRO 2006 Campaign

    Directory of Open Access Journals (Sweden)

    A. J. Kalafut-Pettibone

    2011-09-01

    Full Text Available Measurements of the aerosol size distribution from 11 nm to 2.5 microns were made in Mexico City in March 2006, during the MILAGRO (Megacity Initiative: Local and Global Research Observations field campaign. Observations at the urban supersite, referred to as T0, could often be characterized by morning conditions with high particle mass concentrations, low mixing heights, and highly correlated particle number and CO2 concentrations, indicative that particle number is controlled by primary emissions. Average size-resolved and total number- and volume-based emission factors for combustion sources impacting T0 have been determined using a comparison of peak sizes in particle number and CO2 concentration. Peaks are determined by subtracting the measured concentration from a calculated baseline concentration time series. The number emission and volume emission factors for particles from 11 nm to 494 nm are 1.56 × 1015 particles, and 9.48 × 1011 cubic microns per kg of carbon, respectively. The uncertainty of the number emission factor is approximately plus or minus 50 %. The mode of the number emission factor was between 25 and 32 nm, while the mode of the volume factor was between 0.25 and 0.32 microns. These emission factors are reported as log normal model parameters and are compared with multiple emission factors from the literature. In Mexico City in the afternoon, the CO2 concentration drops during ventilation of the polluted layer, and the coupling between CO2 and particle number breaks down, especially during new particle formation events when particle number is no longer controlled by primary emissions. Using measurements of particle number and CO2 taken aboard the NASA DC-8, the determined primary emission factor was applied to the Mexico City Metropolitan Area (MCMA plume to quantify the degree of secondary particle formation in the plume; the primary emission

  3. Size-resolved aerosol emission factors and new particle formation/growth activity occurring in Mexico City during the MILAGRO 2006 Campaign

    Energy Technology Data Exchange (ETDEWEB)

    Kalafut-Pettibone A. J.; Wang J.; Eichinger, W. E.; Clarke, A.; Vay, S. A.; Blake, D. R.; Stanier, C. O.

    2011-09-01

    Measurements of the aerosol size distribution from 11 nm to 2.5 microns were made in Mexico City in March 2006, during the MILAGRO (Megacity Initiative: Local and Global Research Observations) field campaign. Observations at the urban supersite, referred to as T0, could often be characterized by morning conditions with high particle mass concentrations, low mixing heights, and highly correlated particle number and CO{sub 2} concentrations, indicative that particle number is controlled by primary emissions. Average size-resolved and total number- and volume-based emission factors for combustion sources impacting T0 have been determined using a comparison of peak sizes in particle number and CO{sub 2} concentration. Peaks are determined by subtracting the measured concentration from a calculated baseline concentration time series. The number emission and volume emission factors for particles from 11 nm to 494 nm are 1.56 x 10{sup 15} particles, and 9.48 x 10{sup 11} cubic microns per kg of carbon, respectively. The uncertainty of the number emission factor is approximately plus or minus 50 %. The mode of the number emission factor was between 25 and 32 nm, while the mode of the volume factor was between 0.25 and 0.32 microns. These emission factors are reported as log normal model parameters and are compared with multiple emission factors from the literature. In Mexico City in the afternoon, the CO{sub 2} concentration drops during ventilation of the polluted layer, and the coupling between CO{sub 2} and particle number breaks down, especially during new particle formation events when particle number is no longer controlled by primary emissions. Using measurements of particle number and CO{sub 2} taken aboard the NASA DC-8, the determined primary emission factor was applied to the Mexico City Metropolitan Area (MCMA) plume to quantify the degree of secondary particle formation in the plume; the primary emission factor accounts for less than 50 % of the total particle

  4. Invisible Decays in Higgs Pair Production

    CERN Document Server

    Banerjee, Shankha; Spannowsky, Michael

    2016-01-01

    Observation of Higgs pair production is an important long term objective of the LHC physics program as it will shed light on the scalar potential of the Higgs field and the nature of electroweak symmetry breaking. While numerous studies have examined the impact of new physics on di-Higgs production, little attention has been given to the well-motivated possibility of exotic Higgs decays in this channel. Here we investigate the consequences of exotic invisible Higgs decays in di-Higgs production. We outline a search sensitive to such invisible decays in the $b\\bar b+{\

  5. Quantum Detection and Invisibility in Coherent Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Fransson, J.

    2010-04-28

    We address quantum invisibility in the context of electronics in nanoscale quantum structures. In analogy with metamaterials, we use the freedom of design that quantum corrals provide and show that quantum mechanical objects can be hidden inside the corral, with respect to inelastic electron scattering spectroscopy in combination with scanning tunneling microscopy, and we propose a design strategy. A simple illustration of the invisibility is given in terms of an elliptic quantum corral containing a molecule, with a local vibrational mode, at one of the foci. Our work has implications to quantum information technology and presents new tools for nonlocal quantum detection and distinguishing between different molecules.

  6. Disappearing act[Making objects invisible

    Energy Technology Data Exchange (ETDEWEB)

    Leonhardt, U.; Philbin, T. [University of St Andrews (United Kingdom)]. E-mail: ulf@st-and.ac.uk

    2006-09-15

    Two teams of researchers have recently devised a way to make objects invisible. Ulf Leonhardt and Thomas Philbin describe how this magical feat combines two of the greatest theories in physics: Einstein's general theory of relativity and Maxwell's electromagnetism. Few examples illustrate this better than the recent prediction by two independent groups that materials with exotic electromagnetic properties can make an object disappear. Even more intriguingly, it seems that the best way to actually engineer such an invisibility device is to follow the mathematics of general relativity. (U.K.)

  7. A feeling of being (in)visible

    DEFF Research Database (Denmark)

    Damsgaard, Janne Brammer; Bastrup, Lene; Norlyk, Annelise

    Abstract PhD Day 2015 The illness trajectory of spine fusion patients. A feeling of being (in)visible Background Research shows that being a back patient is associated with great personal cost, and that back patients who undergo so-called spine fusion often experience particularly long and uncoor......Abstract PhD Day 2015 The illness trajectory of spine fusion patients. A feeling of being (in)visible Background Research shows that being a back patient is associated with great personal cost, and that back patients who undergo so-called spine fusion often experience particularly long...

  8. Every mother and child count: overcoming invisibility.

    Science.gov (United States)

    Callister, Lynn Clark

    2012-01-01

    While statistics document shocking and sobering facts about disparities in women's health and women's quality of life around the world, they do not portray the lives of women individually or recognize the importance of listening to their voices. Reasons for the continuing invisibility of women include issues related to mission, attitudes, evaluation, translation, prevention, integration, empowerment, organization, advocacy and leadership. This article explains the underpinnings of these contributors to women's invisibility and offers readers ways to become more fully engaged in global health initiatives to make women and children more visible. © 2012 AWHONN.

  9. Gait identification from invisible shadows

    Science.gov (United States)

    Iwashita, Yumi; Uchino, Koji; Kurazume, Ryo; Stoica, Adrian

    2012-06-01

    This paper introduces a person identification system that uses as input the shadow images of a walking person, as projected by multiple lights(in this application invisible/infrared lights); the system uses a database of examples of shadows images of a number of people who walk. While it is accepted that personal identification has a higher correct classification rate if views from multiple cameras are used, most systems use only one camera, mainly because (i) Installation in real-world environments is easier, less cameras and no need to synchronize cameras, (ii) Computational cost is reduced. In the proposed system, we obtain the advantages of multiple viewpoints with a single camera and additional light sources. More specific, we install multiple infrared lights to project shadows of a subject on the ground and a camera with an infrared transmitting filter mounted in the ceiling inside of a building. Shadow areas, which are projections of one's body on the ground by multiple lights, can be considered as body areas captured from different viewpoints; thus, the proposed system is able to capture multiple projections of the body from a single camera. We explored in other papers the use of sunproduced shadow for identification of people walking freely in the outdoor. In this paper the application scenario is a system installed at the airport in the areas that precedes the immigration checkpoint. Japan already has health monitoring cameras focused on approaching individuals, to determine their health condition; the here described system would also be installed in such a controlled area with restricted walk corridors of walk and controlled lighting. Gait is a remote biometrics and can provide early warning; on another hand it can be used as corroborating evidence in a multi-modal biometrics system. A database of images including shadows for a set of 28 walking people was collected, and the features extracted from shadow areas by affine moment invariants, after which

  10. Beyond Google: The Invisible Web in the Academic Library

    Science.gov (United States)

    Devine, Jane; Egger-Sider, Francine

    2004-01-01

    This article analyzes the concept of the Invisible Web and its implication for academic librarianship. It offers a guide to tools that can be used to mine the Invisible Web and discusses the benefits of using the Invisible Web to promote interest in library services. In addition, the article includes an expanded definition, a literature review,…

  11. TThe analysis of air pollution caused by particle matter emission from the copper smelter complex bor (Serbia

    Directory of Open Access Journals (Sweden)

    Nevenka Petrović

    2010-09-01

    Full Text Available The main aim of this paper is to present the analyses of temporal variations of particulate matter in Bor (Serbia influenced by the copper production at the Copper Smelter Complex Bor. Particulate emissions are of concern because the presence of fine particles (PM2.5 – particles with diametar less than 2.5 μm and ultrafine particles (PM0.1 – particles with diametar less than 0.1 μm assume higher risk for human health. Such particles can penetrate deeper into respiratory organs and, at the same time, a probability for such penetration and deposition in the respiratory system is greater. The analysis is based on the comparison of SO2 and PM measurements at several locations in the area of Bor town in the close vicinity of Copper Smelter. PM concentrations were highly correlated with sulfur dioxide and inversely correlated with local wind speed during pollution episodes. The results presented indicate that the dominant source of coarse and fine particles in Bor town is the Copper Smelting Complex Bor. The most significant factors for particulate matter distribution are meteorological parameters of the wind speed and direction. It was found that the daily limit values exceed of concentrations of PM10 (50 μg/m3 usually occurs due to very high concentrations in a period of several hours during the day.

  12. Gas- and particle-phase distribution of polycyclic aromatic hydrocarbons in two-stroke, 50-cm 3 moped emissions

    Science.gov (United States)

    Spezzano, Pasquale; Picini, Paolo; Cataldi, Dario

    Gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) concentrations evaluated in the exhaust of 10 two-stroke, 50-cm 3 mopeds belonging to three different levels of emission legislation (EURO-0, EURO-1 and EURO-2) were used to assess the prevalent mechanism driving the gas/particle partitioning of PAHs in moped exhaust. Sampling was performed on a dynamometer bench both during the "cold-start" and the "hot" phases of the ECE-47 driving cycle. Gas and particulate phase PAHs were collected on polyurethane foam (PUF) plugs and 47-mm Pallflex T60A20 filters, respectively, under isokinetic conditions by using sampling probes inserted into the dilution tunnel of a Constant Volume Sampling - Critical Flow Venturi (CVS-CFV) system. The results show that semi-volatile PAHs were predominantly partitioned to the particle phase. The soluble organic fraction (SOF) of the collected particulates ranged between 72 and 98%. Measured total suspended particulate matter normalized partition coefficients ( Kp) were predicted within a factor of 3-5 by assuming absorption into the organic fraction according to a model developed by Harner and Bidleman [Harner, T., Bidleman, T.F., 1998. Octanol-air partition coefficient for describing particle/gas partitioning of aromatic compounds in urban air. Environmental Science & Technology 32, 1494-1502.]. This suggests that the gas/particle partitioning in moped exhaust is mainly driven by the high fraction of organic matter of the emitted particles and that absorption could be the main partitioning mechanism of PAHs.

  13. Searches for invisible Higgs boson decays with ATLAS and CMS

    CERN Document Server

    Calfayan, Philippe; The ATLAS collaboration

    2015-01-01

    The ATLAS and CMS experiments carried out searches for invisible decays of the Higgs boson. The analyses have been led in final states with missing energy in the transverse plane of the detector, in the case of typical signatures where the Higgs boson is produced in association with an electroweak vector boson, or via gluon-gluon or vector boson fusion. Upper bounds on the branching fraction of a Higgs boson decaying to invisible particles have been derived as function of the assumed mass of the Higgs boson. Additional interpretations have been considered in the context of Higgs-portal models, which resulted in constraints on the production of Dark Matter candidates. The searches are based on the complete datasets from the Run-1 of the Large Hadron Collider, which includes proton-proton collision at a center-of-mass energy of $\\sqrt{s}=7$ or $8\\,\\mathrm{TeV}$, with up to $20\\,\\mathrm{fb}^{-1}$ of integrated luminosity.

  14. Removal of viable bioaerosol particles with a low-efficiency HVAC filter enhanced by continuous emission of unipolar air ions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, R.; Agranovski, I.; Pyankov, O. (Griffith Univ., Nathan, Qld (AU)); Grinshpun, S. (Univ. of Cincinnati, Dept. of Environmental Health, Cincinnati, OH (US))

    2008-04-15

    Continuous emission of unipolar ions has been shown to improve the performance of respirators and stationary filters challenged with non-biological particles. In this study, we investigated the ion-induced enhancement effect while challenging a low-efficiency heating, ventilation and air-conditioning (HVAC) filter with viable bacterial cells, bacterial and fungal spores, and viruses. The aerosol concentration was measured in real time. Samples were also collected with a bioaerosol sampler for viable microbial analysis. The removal efficiency of the filter was determined, respectively, with and without an ion emitter. The ionization was found to significantly enhance the filter efficiency in removing viable biological particles from the airflow. For example, when challenged with viable bacteria, the filter efficiency increased as much as four- to fivefold. For viable fungal spores, the ion-induced enhancement improved the efficiency by a factor of approx 2. When testing with virus-carrying liquid droplets, the original removal efficiency provided by the filter was rather low: 9.09 +- 4.84%. While the ion emission increased collection about fourfold, the efficiency did not reach 75-100% observed with bacteria and fungi. These findings, together with our previously published results for non-biological particles, demonstrate the feasibility of a new approach for reducing aerosol particles in HVAC systems used for indoor air quality control. (au)

  15. Assessment of Microphysical Models in the National Combustion Code (NCC) for Aircraft Particulate Emissions: Particle Loss in Sampling Lines

    Science.gov (United States)

    Wey, Thomas; Liu, Nan-Suey

    2008-01-01

    This paper at first describes the fluid network approach recently implemented into the National Combustion Code (NCC) for the simulation of transport of aerosols (volatile particles and soot) in the particulate sampling systems. This network-based approach complements the other two approaches already in the NCC, namely, the lower-order temporal approach and the CFD-based approach. The accuracy and the computational costs of these three approaches are then investigated in terms of their application to the prediction of particle losses through sample transmission and distribution lines. Their predictive capabilities are assessed by comparing the computed results with the experimental data. The present work will help establish standard methodologies for measuring the size and concentration of particles in high-temperature, high-velocity jet engine exhaust. Furthermore, the present work also represents the first step of a long term effort of validating physics-based tools for the prediction of aircraft particulate emissions.

  16. Environmental Particle Emissions due to Automated Drilling of Polypropylene Composites and Nanocomposites Reinforced with Talc, Montmorillonite and Wollastonite

    Science.gov (United States)

    Starost, K.; Frijns, E.; Laer, J. V.; Faisal, N.; Egizabal, A.; Elizextea, C.; Nelissen, I.; Blazquez, M.; Njuguna, J.

    2017-05-01

    In this study, the effect on nanoparticle emissions due to drilling on Polypropylene (PP) reinforced with 20% talc, 5% montmorillonite (MMT) and 5% Wollastonite (WO) is investigated. The study is the first to explore the nanoparticle release from WO and talc reinforced composites and compares the results to previously researched MMT. With 5% WO, equivalent tensile properties with a 10 % weight reduction were obtained relative to the reference 20% talc sample. The materials were fabricated through injection moulding. The nanorelease studies were undertaken using the controlled drilling methodology for nanoparticle exposure assessment developed within the European Commission funded SIRENA Life 11 ENV/ES/506 project. Measurements were taken using CPC and DMS50 equipment for real-time characterization and measurements. The particle number concentration (of particles talc sample emitted larger particle diameters.

  17. Comparison of carcinogen, carbon monoxide, and ultrafine particle emissions from narghile waterpipe and cigarette smoking: Sidestream smoke measurements and assessment of second-hand smoke emission factors

    Science.gov (United States)

    Daher, Nancy; Saleh, Rawad; Jaroudi, Ezzat; Sheheitli, Hiba; Badr, Thérèse; Sepetdjian, Elizabeth; Al Rashidi, Mariam; Saliba, Najat; Shihadeh, Alan

    2010-01-01

    The lack of scientific evidence on the constituents, properties, and health effects of second-hand waterpipe smoke has fueled controversy over whether public smoking bans should include the waterpipe. The purpose of this study was to investigate and compare emissions of ultrafine particles (UFP, 1.5 air changes per hour (ACH). The chamber was characterized for particle mass and number surface deposition rates. UFP and CO concentrations were measured online using a fast particle spectrometer (TSI 3090 Engine Exhaust Particle Sizer), and an indoor air quality monitor. Particulate PAH and gaseous volatile aldehydes were captured on glass fiber filters and DNPH-coated SPE cartridges, respectively, and analyzed off-line using GC-MS and HPLC-MS. PAH compounds quantified were the 5- and 6-ring compounds of the EPA priority list. Measured aldehydes consisted of formaldehyde, acetaldehyde, acrolein, methacrolein, and propionaldehyde. We found that a single waterpipe use session emits in the sidestream smoke approximately four times the carcinogenic PAH, four times the volatile aldehydes, and 30 times the CO of a single cigarette. Accounting for exhaled mainstream smoke, and given a habitual smoker smoking rate of 2 cigarettes per hour, during a typical one-hour waterpipe use session a waterpipe smoker likely generates ambient carcinogens and toxicants equivalent to 2-10 cigarette smokers, depending on the compound in question. There is therefore good reason to include waterpipe tobacco smoking in public smoking bans.

  18. Comparative Toxicity of Combined Particle and Semi-Volatile Organic Fractions of Gasoline and Diesel Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Mauderly, Joe; Seagrave, JeanClare; McDonald, Jacob; Gigliotti,Andrew; Nikula, Kristen; Seilkop, Steven; Gurevich, Michael

    2002-08-25

    Little is known about the relative health hazards presented by emissions from in-use gasoline and diesel engines. Adverse health effects have been ascribed to engine emissions on the basis of: (1) the presence of known toxic agents in emissions; (2) high-dose animal and bacterial mutagenicity tests; and (3) studies indicating gradients of health effects with proximity to roadways. Most attention has been given to the particulate fraction of emissions; little attention has been given to the semi-volatile organic fraction. However, the semi-volatile fraction overlaps the particulate fraction in composition and is always present in the vicinity of fresh emissions. Although the potential health effects of diesel emissions have been frequently studied and debated during the past 20 years (EPA, 2002), relatively little attention has been given to the toxicity of emissions from gasoline engines. In view of the considerable progress in cleaning up diesel emissions, it would be useful to compare the toxicity of emissions from contemporary on-road diesel technology with that of emissions from the in-use gasoline fleet that is well-accepted by the public. It would also be useful to have a set of validated tests for rapid, cost-effective comparisons of the toxicity of emission samples, both for comparisons among competing technologies (e.g., diesel, gasoline, natural gas) and for determining the impacts of new fuel, engine, and after-treatment strategies on toxicity. The Office of Heavy Vehicle Technologies has sponsored research aimed at developing and applying rapid-response toxicity tests for collected emission samples (Seagrave et al., 2000). This report presents selected results from that work, which is being published in much greater detail in the peer-reviewed literature (Seagrave et al., 2002).

  19. Factors affecting non-tailpipe aerosol particle emissions from paved roads: On-road measurements in Stockholm, Sweden

    Science.gov (United States)

    Hussein, Tareq; Johansson, Christer; Karlsson, Hans; Hansson, Hans-Christen

    A large fraction of urban PM 10 concentrations is due to non-exhaust traffic emissions. In this paper, a mobile measurement system has been used to quantify the relative importance of road particle emission and suspension of accumulated dust versus direct pavement wear, tire type (studded, friction, and summer), pavement type, and vehicle speed. Measurements were performed during May-September on selected roads with different pavements and traffic conditions in the Stockholm region. The highest particle mass concentrations were always observed behind the studded tire and the lowest were behind the summer tire; studded-to-summer ratios were 4.4-17.3 and studded-to-friction ratios were 2.0-6.4. This indicates that studded tires lead to higher emissions than friction and summer tires regardless to the asphalt type. By comparing with measurements in a road simulator, it could be estimated that the pavement wear due to the friction tires was 0.018-0.068 of the suspension of accumulated road dust. Likewise for studded tires road-wear was estimated to be 1.2-4.8 the suspension of accumulated dust. This indicates that wear due to friction tires is very small compared to the suspension of accumulated dust and that suspension due to studded tires may sometimes be as large as the wear of the road. But this will vary depending on, e.g. the amount of dust accumulated on the roads. An important dependence on vehicle speed was also observed. During May, the particle mass concentrations behind the studded tire at vehicle speed 100 km h -1 were about 10 times higher than that at 20 km h -1. The speed dependence was not so pronounced in September, which could be due to less accumulated dust on the roads. The particle number size distribution of the emissions due to road wear by studded tire was characterized by a clear increase in number concentrations of the coarse fraction of aerosol particles, with a geometric mean diameter between 3 and 5 μm. The size distribution of the

  20. Combining four dimensional variational data assimilation and particle filtering for estimating volcanic ash emissions

    Science.gov (United States)

    Franke, Philipp; Elbern, Hendrik

    2016-04-01

    Estimating volcanic ash emissions is a very challenging task due to limited monitoring capacities of the ash plume and nonlinear processes in the atmosphere, which renders application of source strength and injection height estimations difficult. Most models, which estimate volcanic ash emissions, make strong simplifications of the dispersion of volcanic ash and corresponding atmospheric processes. The objective of this work is to estimate volcanic ash emissions and simulate the ensuing dispersion applying a full chemistry transport model in a hybrid approach by using its adjoint as well as an ensemble of model runs to quantify forecast uncertainties. Therefore, the four dimensional variational data assimilation version of the EURAD-IM chemistry transport model is extended to include a Sequential Importance Resampling Smoother (SIRS), introducing novel weighting and resampling strategies. In the main SIRS step the ensemble members exchange high rated emission patterns while rejecting emission patterns with low value for the forecast. The emission profiles of the ensemble members are perturbed afterwards to guarantee different emissions for all ensemble members. First identical twin experiments show the ability of the system to estimate the temporal and vertical distribution of volcanic ash emissions. The 4D-var data assimilation algorithm of the new system additionally provides quantitative emission estimation.

  1. 4-Nitrophenol, 1-nitropyrene, and 9-nitroanthracene emissions in exhaust particles from diesel vehicles with different exhaust gas treatments

    Science.gov (United States)

    Inomata, Satoshi; Fushimi, Akihiro; Sato, Kei; Fujitani, Yuji; Yamada, Hiroyuki

    2015-06-01

    The dependence of nitro-organic compound emissions in automotive exhaust particles on the type of aftertreatment used was investigated. Three diesel vehicles with different aftertreatment systems (an oxidation catalyst, vehicle-DOC; a particulate matter and NOx reduction system, vehicle-DPNR; and a urea-based selective catalytic reduction system, vehicle-SCR) and a gasoline car with a three-way catalyst were tested. Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) and nitrophenols in the particles emitted were analyzed by thermal desorption gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry. The secondary production of nitro-organic compounds on the filters used to collect particles and the adsorption of gaseous nitro-organic compounds by the filters were evaluated. Emissions of 1-nitropyrene, 9-nitroanthracene, and 4-nitrophenol in the diesel exhaust particles were then quantified. The NOx reduction process in vehicle-DPNR appeared to remove nitro-hydrocarbons efficiently but not to remove nitro-oxygenated hydrocarbons efficiently. The nitro-PAH emission factors were lower for vehicle-DOC when it was not fitted with a catalyst than when it was fitted with a catalyst. The 4-nitrophenol emission factors were also lower for vehicle-DOC with a catalyst than vehicle-DOC without a catalyst, suggesting that the oxidation catalyst was a source of both nitro-PAHs and 4-nitrophenol. The time-resolved aerosol mass spectrometry data suggested that nitro-organic compounds are mainly produced when an engine is working under load. The presence of 4-nitrophenol in the particles was not confirmed statistically because of interference from gaseous 4-nitrophenol. Systematic errors in the estimated amounts of gaseous 1-nitropyrene and 9-nitroanthracene adsorbed onto the filters and the estimated amounts of volatile nitro-organic compounds that evaporated during sampling and during post-sampling conditioning could not be excluded. An analytical method

  2. Development of particle induced X-ray emission facility at cyclotron laboratory and its prospective applications

    Energy Technology Data Exchange (ETDEWEB)

    Puri, N.K. [Department of Applied Physics, Delhi Technological Universily (Formerly Delhi College of Engineering, DCE), Delhi (India); Garg, M.L. [Department of Bio-Physics, Panjab Universily, Chandigarh (India); Govil, I.M. [Department of Physics, Panjab University, Chandigarh (India)

    2013-07-01

    Full text: We are presenting here a description of modifications in the Variable Energy Cyclotron (VEC) Chandigarh along with the installation of Proton Induced X-ray Emission (PIXE) setup. The installation of new main magnet power supply of 400A/125V out put with 10 ppm stability (model 853 M/S Danfysik, Denmark) and a new stabilized solid state power supply for RF oscillator gave the beam characteristics substantially good enough for PIXE work. A new chamber [1] was designed to cater for Proton Induced Gamma Emission (PIGE) and Rutherford Back Scattering (RBS) analysis along with PIXE measurements. The HPGe X-ray detector, the Ge(Li) -ray detector and a Silicon Surface Barrier (SSB) detector could be mounted simultaneously in the chamber. A Turbo-Molecular vacuum pump was provided to produce a clean vacuum of the order of 10{sup -7} torr in PIXE chamber. A remotely controlled stepper motor could move the 12/24-position target holder. Beam size optimization along with the minimization of background was done with the help of graphite collimators, thus making the setup suitable for practical applications. We attempted to address some of the limitations using PIXE facility of Institute of Physics (IOP), India [2] and incorporated modifications (e.g. chamber design, sample holder etc.) in our set-up. Preliminary experiments for the PIXE analysis of aerosol samples, gunshot residues samples and bone samples were presented. The aerosol samples were collected using aerosol sampling kit which involves Millipore diaphragmatic vacuum pump and Sequential Filter Unit (SFU) with coarse pored Nucleo pore polycarbonate filter in such a manner that the particles passing through the 8m pore size filter were collected on the 0.4m pore size filter. Two different pistols viz. 7.65mm Indian made and 7.63mm Germany made were used to fire at a filter paper target with card board and cotton wool backing from a distance of 3 feet. Two sheets of Whatman filter paper were used to form the

  3. Positron emission particle tracking - a technique for studying flow within engineering equipment

    Energy Technology Data Exchange (ETDEWEB)

    Parker, D.J.; Hawkesworth, M.R.; McNeil, P. (School of Physics and Space Research, Birmingham (United Kingdom)); Broadbent, C.J. (School of Chemical Engineering, Birmingham (United Kingdom)); Fowles, P. (School of Chemistry, Univ. Birmingham (United Kingdom))

    1993-03-10

    The use of the Birmingham positron camera for tracking positron-emitting particles within engineering structures has been investigated, using particles containing typically 4 MBq (100 [mu]Ci) [sup 18]F or [sup 22]Na. An algorithm for discarding [gamma]-ray trajectories corrupted by scattering, etc., and using the remaining trajectories to compute the particle's location in three dimensions has been developed, and its performance explained. A slowly moving particle can be located to within 1 mm several times per second, while a particle moving at 1 ms[sup -1] can be located to within 5 mm 50 times per second, through a considerable thickness of surrounding material. An example of results obtained from tracking a particle in a rotating drum of powder illustrates the potential value of the technique. (orig.).

  4. Size-resolved aerosol emission factors and new particle formation/growth activity occurring in Mexico City during the MILAGRO 2006 Campaign

    Directory of Open Access Journals (Sweden)

    A. J. Kalafut-Pettibone

    2011-02-01

    Full Text Available Measurements of the aerosol size distribution from 11 nm to 2.5 microns were made in Mexico City in March, 2006, during the MILAGRO field campaign. Observations at the T0 research site could often be characterized by morning conditions with high particle mass concentrations, low mixing heights, and highly correlated particle number and CO2 concentrations, indicative that particle number is controlled by primary emissions. Average size-resolved and total number- and volume-based emission factors for combustion sources impacting T0 have been determined using a comparison of peak sizes in number and CO2 concentration peaks. The number emission and volume emission factors for particles from 11 nm to 494 nm are 1.23 × 1015 particles, and 7.54 × 1011 cubic microns per kg of carbon, respectively. Uncertainty on the number emission factor is approximately a factor of 1.5. The mode of the number emission factor was between 25 and 32 nm, while the mode of the volume factor was between 0.25 and 0.32 microns. These emission factors are reported as log normal model parameters and are compared with multiple emission factors from the literature. In Mexico City in the afternoon, the CO2 concentration drops during ventilation of the polluted layer, and the coupling between CO2 and particle number breaks down, especially during new particle formation events when particle number is no longer controlled by primary emissions. Using measurements of particle number and CO2 taken aboard the NASA DC-8, this emission factor was applied to the MCMA plume; the primary emission factor predicts less than 50% of the total particle number and the surplus particle count is not correlated with photochemical age. Primary particle volume and number in the size range 0.1–2 μm are similarly too low to predict the observed volume distribution. Contrary to the case for number, the apparent secondary

  5. Getting To Know the "Invisible Web."

    Science.gov (United States)

    Smith, C. Brian

    2001-01-01

    Discusses the portions of the World Wide Web that cannot be accessed via directories or search engines, explains why they can't be accessed, and offers suggestions for reference librarians to find these sites. Lists helpful resources and gives examples of invisible Web sites which are often databases. (LRW)

  6. Can even monochromatic radiation ensure ideal invisibility?

    Energy Technology Data Exchange (ETDEWEB)

    Rozanov, Nikolai N [St. Petersburg State University of Information Technologies, Mechanics and Optics, St.-Petersburg (Russian Federation)

    2011-07-31

    Discusses conclusions reached by A E Dubinov and D A Mytareva in their paper 'Invisible cloaking of material bodies using the wave flow method' (Usp. Fiz. Nauk 180 475 (2010) [Phys. Usp. 53 455 (2010)]) on whether the perfect optical cloaking of material objects is possible. (letters to the editors)

  7. Invisible Mentor: Communication Theory and Lilian Katz.

    Science.gov (United States)

    Peterson, Karen L.

    This paper describes the influence of Lilian G. Katz on the dissemination of knowledge in early childhood education. Communication theory, women's learning, and the role of the "invisible mentor" are presented as a model for understanding the impact of Katz's perspectives on the profession. The paper considers two major elements in…

  8. The Treatment of Smith's Invisible Hand

    Science.gov (United States)

    Wight, Jonathan B.

    2007-01-01

    Adam Smith used the metaphor of an invisible hand to represent the instincts of human nature that direct behavior. Moderated by self-control and guided by proper institutional incentives, actions grounded in instincts can be shown to generate a beneficial social order even if not intended. Smith's concept, however, has been diluted and distorted…

  9. Macroscopic invisibility cloaking of visible light

    DEFF Research Database (Denmark)

    Chen, Xianzhong; Luo, Y.; Zhang, Jingjing

    2011-01-01

    to a few wavelengths. Here, we report the first realization of a macroscopic volumetric invisibility cloak constructed from natural birefringent crystals. The cloak operates at visible frequencies and is capable of hiding, for a specific light polarization, three-dimensional objects of the scale...

  10. CHORUS : snapshots of the invisible

    CERN Multimedia

    Jean Leyder

    1996-01-01

    It's the fifth of May 1994, we are in the European Center for Particle Physics, CERN in Geneva, the last adjustments are been made on CHORUS, a giant microscope for viewing infinitely small particules, particules which move at the speed of light ....

  11. Effect of flow characteristics on ultrafine particle emissions from range hoods.

    Science.gov (United States)

    Tseng, Li-Ching; Chen, Chih-Chieh

    2013-08-01

    In order to understand the physical mechanisms of the production of nanometer-sized particulate generated from cooking oils, the ventilation of kitchen hoods was studied by determining the particle concentration, particle size distribution, particle dimensions, and hood's flow characteristics under several cooking scenarios. This research varied the temperature of the frying operation on one cooking operation, with three kinds of commercial cooking oils including soybean oil, olive oil, and sunflower oil. The variations of particle concentration and size distributions with the elevated cooking oil temperatures were presented. The particle concentration increases as a function of temperature. For oil temperatures ranging between 180°C and 210°C, a 5°C increase in temperature increased the number concentration of ultrafine particles by 20-50%. The maximum concentration of ultrafine particles was found to be approximately 6 × 10(6) particles per cm(3) at 260°C. Flow visualization techniques and particle distribution measurement were performed for two types of hood designs, a wall-mounted range hood and an island hood, at a suction flow rate of 15 m(3) min(-1). The flow visualization results showed that different configurations of kitchen hoods induce different aerodynamic characteristics. By comparing the results of flow visualizations and nanoparticle measurements, it was found that the areas with large-scale turbulent vortices are more prone to dispersion of ultrafine particle leakage because of the complex interaction between the shear layers and the suction movement that results from turbulent dispersion. We conclude that the evolution of ultrafine particle concentration fluctuations is strongly affected by the location of the hood, which can alter the aerodynamic features. We suggest that there is a correlation between flow characteristics and amount of contaminant leakage. This provides a comprehensive strategy to evaluate the effectiveness of kitchen hoods

  12. Ultrafine Particles from Traffic Emissions and Children’s Health (UPTECH in Brisbane, Queensland (Australia: Study Design and Implementation

    Directory of Open Access Journals (Sweden)

    Wafaa Nabil Ezz

    2015-02-01

    Full Text Available Ultrafine particles are particles that are less than 0.1 micrometres (µm in diameter. Due to their very small size they can penetrate deep into the lungs, and potentially cause more damage than larger particles. The Ultrafine Particles from Traffic Emissions and Children’s Health (UPTECH study is the first Australian epidemiological study to assess the health effects of ultrafine particles on children’s health in general and peripheral airways in particular. The study is being conducted in Brisbane, Australia. Continuous indoor and outdoor air pollution monitoring was conducted within each of the twenty five participating school campuses to measure particulate matter, including in the ultrafine size range, and gases. Respiratory health effects were evaluated by conducting the following tests on participating children at each school: spirometry, forced oscillation technique (FOT and multiple breath nitrogen washout test (MBNW (to assess airway function, fraction of exhaled nitric oxide (FeNO, to assess airway inflammation, blood cotinine levels (to assess exposure to second-hand tobacco smoke, and serum C-reactive protein (CRP levels (to measure systemic inflammation. A pilot study was conducted prior to commencing the main study to assess the feasibility and reliably of measurement of some of the clinical tests that have been proposed for the main study. Air pollutant exposure measurements were not included in the pilot study.

  13. Formation and emission of fine particles from two coal-fired power plants

    DEFF Research Database (Denmark)

    Nielsen, M.T.; Livbjerg, H.; Fogh, C.L.

    2002-01-01

    , and Fe under reducing conditions. Several other ash-contained elements, e.g., P, Ba, Co, Cu, Mn, Ni, Ph, V, and Zn, are partly vaporized in the boiler and enrich the small particles when they condense during cooling of the flue gas. Due to the higher penetration of the small particles through the filter...

  14. PAH, BTEX, carbonyl compound, black-carbon, NO2 and ultrafine particle dynamometer bench emissions for Euro 4 and Euro 5 diesel and gasoline passenger cars

    Science.gov (United States)

    Louis, Cédric; Liu, Yao; Tassel, Patrick; Perret, Pascal; Chaumond, Agnès; André, Michel

    2016-09-01

    Although implementing Diesel particulate filters (DPF) and other novel aftertreatment technologies makes it possible to achieve significant reductions in particle mass emissions, it may induce the release of ultrafine particles and emissions of many other unregulated compounds. This paper focuses on (i) ultrafine particles, black carbon, BTEX, PAH, carbonyl compounds, and NO2 emissions from Euro 4 and Euro 5 Diesel and gasoline passenger cars, (ii) the influence of driving conditions (e.g., cold start, urban, rural and motorway conditions), and (iii) the impact of additive and catalysed DPF devices on vehicle emissions. Chassis dynamometer tests were conducted on four Euro 5 vehicles and two Euro 4 vehicles: gasoline vehicles with and without direct injection system and Diesel vehicles equipped with additive and catalysed particulate filters. The results showed that compared to hot-start cycles, cold-start urban cycles increased all pollutant emissions by a factor of two. The sole exception was NO2, which was reduced by a factor of 1.3-6. Particulate and black carbon emissions from the gasoline engines were significantly higher than those from the Diesel engines equipped with DPF. Moreover, the catalysed DPF emitted about 3-10 times more carbonyl compounds and particles than additive DPF, respectively, during urban driving cycles, while the additive DPF vehicles emitted 2 and 5 times more BTEX and carbonyl compounds during motorway driving cycles. Regarding particle number distribution, the motorway driving cycle induced the emission of particles smaller in diameter (mode at 15 nm) than the urban cold-start cycle (mode at 80-100 nm). The results showed a clear positive correlation between particle, black carbon, and BTEX emissions, and a negative correlation between particles and NO2.

  15. Direct evidence for coastal iodine particles from Laminaria macroalgae – linkage to emissions of molecular iodine

    Directory of Open Access Journals (Sweden)

    D. Wevill

    2004-02-01

    Full Text Available Renewal of ultrafine aerosols in the marine boundary layer may lead to repopulation of the marine distribution and ultimately determine the concentration of cloud condensation nuclei (CCN. Thus the formation of nanometre-scale particles can lead to enhanced scattering of incoming radiation and a net cooling of the atmosphere. The recent demonstration of the chamber formation of new particles from the photolytic production of condensable iodine-containing compounds from diiodomethane (CH2I2, (O'Dowd et al., 2002; Kolb, 2002; Jimenez et al., 2003a; Burkholder and Ravishankara, 2003, provides an additional mechanism to the gas-to-particle conversion of sulphuric acid formed in the photo-oxidation of dimethylsulphide for marine aerosol repopulation. CH2I2 is emitted from seaweeds (Carpenter et al., 1999, 2000 and has been suggested as an initiator of particle formation. We demonstrate here for the first time that ultrafine iodine-containing particles are produced by intertidal macroalgae exposed to ambient levels of ozone. The particle composition is very similar both to those formed in the chamber photo-oxidation of diiodomethane and in the oxidation of molecular iodine by ozone. The particles formed in all three systems are similarly aspherical and behave alike when exposed to increased humidity environments. Direct coastal boundary layer observations of molecular iodine, ultrafine particle production and iodocarbons are reported. Using a newly measured molecular iodine photolysis rate, it is shown that, if atomic iodine is involved in the observed particle bursts, it is of the order of at least 1000 times more likely to result from molecular iodine photolysis than diiodomethane photolysis. A hypothesis for molecular iodine release from intertidal macroalgae is presented and the potential importance of macroalgal iodine particles in their contribution to CCN and global radiative forcing are discussed.

  16. Background dust emission following grassland fire: a snapshot across the particle-size spectrum highlights how high-resolution measurements enhance detection

    Energy Technology Data Exchange (ETDEWEB)

    Whicker, Jeffrey J [Los Alamos National Laboratory; Martin, Luis M [UNIV OF ARIZONA; Field, Jason P [UNIV OF ARIZONA; Villegas, Juan C [UNIV OF ARIZONA; Brehsears, David D [UNIV OF ARIZONA; Law, Darin J [UNIV OF ARIZONA; Urgeghe, Anna M [UNIV OF ARIZONA

    2009-01-01

    Dust emission rates vary temporally and with particle size. Many studies of dust emission focus on a particular temporal scale and the portion of the particle-size spectrum associated with a single instrument; fewer studies have assessed dust emission across the particle-size spectrum and associated temporal scales using multiple instruments. Particularly lacking are measurements following disturbances such as fire that are high-resolution and focused on finer particles - those with direct implications for human health and potential for long-distance biogeochemical transport - during less windy but more commonly occurring background conditions. We measured dust emissions in unburned and burned semiarid grassland using four different instruments spanning different combinations of temporal resolution and particle-size spectrum: Big Springs Number Eight (BSNE) and Sensit instruments for larger saltating particles, DustTrak instruments for smaller suspended particles, and Total Suspended Particulate (TSP) samplers for measuring the entire range of particle sizes. Unburned and burned sites differed in vegetation cover and aerodynamic roughness, yet surprisingly differences in dust emission rates were only detectable for saltation using BSNE and for smaller aerosols using DustTrak. Our results, surprising in the lack of consistently detected differences, indicate that high-resolution DustTrak measurements offered the greatest promise for detecting differences in background emission rates and that BSNE samplers, which integrate across height, were effective for longer intervals. More generally, our results suggest that interplay between particle size, temporal resolution, and integration across time and height can be complex and may need to be considered more explicitly for effective sampling for background dust emissions.

  17. Pourquoi les quarks restent invisibles

    CERN Multimedia

    Gross, David J

    2005-01-01

    At the beginning of the seventies, physicists discovered a new scale in the matter structure. Protons and neutrons, components of the atomic nucleus, seemed to be constituted by even more elementar particles: the quarks. But while they seemed to move freely inside the protons, it was impossible to isolate one of these quarks. The Nobel Prize for physics rewarded the explanation of this phenomenon (3 pages)

  18. Search for $D^{0}$ decays to invisible final states at Belle

    CERN Document Server

    Lai, Y -T; Adachi, I; Aihara, H; Said, S Al; Asner, D M; Aushev, T; Ayad, R; Badhrees, I; Bakich, A M; Bansal, V; Barberio, E; Berger, M; Bhardwaj, V; Bhuyan, B; Biswal, J; Bobrov, A; Bozek, A; Bračko, M; Črvenkov, D; Chang, P; Chen, A; Cheon, B G; Chilikin, K; Chistov, R; Cho, K; Chobanova, V; Choi, Y; Cinabro, D; Dash, N; Di Carlo, S; Doležal, Z; Dutta, D; Eidelman, S; Epifanov, D; Farhat, H; Fast, J E; Ferber, T; Fulsom, B G; Gaur, V; Gabyshev, N; Garmash, A; Gillard, R; Goldenzweig, P; Golob, B; Hayasaka, K; Hou, W -S; Hsu, C -L; Iijima, T; Inami, K; Inguglia, G; Ishikawa, A; Itoh, R; Iwasaki, Y; Jacobs, W W; Jaegle, I; Jeon, H B; Joffe, D; Joo, K K; Julius, T; Kang, K H; Kawasaki, T; Kim, D Y; Kim, J B; Kim, K T; Kim, M J; Kim, S H; Kim, Y J; Kinoshita, K; Kodyš, P; Kotchetkov, D; Krokovny, P; Kuhr, T; Kulasiri, R; Kwon, Y -J; Lange, J S; Lee, I S; Li, C H; Li, L; Li, Y; Gioi, L Li; Libby, J; Liventsev, D; Masuda, M; Matsuda, T; Matvienko, D; Miyabayashi, K; Miyata, H; Mizuk, R; Mohanty, G B; Mohanty, S; Nakano, E; Nakao, M; Nakazawa, H; Nanut, T; Nath, K J; Natkaniec, Z; Nayak, M; Nishida, S; Ogawa, S; Okuno, S; Pakhlov, P; Pal, B; Park, H; Paul, S; Pedlar, T K; Piilonen, L E; Pulvermacher, C; Rauch, J; Ritter, M; Sahoo, H; Sakai, Y; Sandilya, S; Sato, Y; Savinov, V; Schlüter, T; Schneider, O; Schnell, G; Schwanda, C; Schwartz, A J; Seino, Y; Semmler, D; Senyo, K; Seong, I S; Shebalin, V; Shen, C P; Shibata, T -A; Shiu, J -G; Simon, F; Solovieva, E; Starič, M; Stypula, J; Sumiyoshi, T; Takizawa, M; Tamponi, U; Tenchini, F; Trabelsi, K; Uchida, M; Uehara, S; Uglov, T; Unno, Y; Uno, S; Urquijo, P; Usov, Y; Van Hulse, C; Varner, G; Varvell, K E; Vorobyev, V; Wang, C H; Watanabe, M; Watanabe, Y; Widmann, E; Won, E; Yamashita, Y; Ye, H; Yook, Y; Yuan, C Z; Yusa, Y; Zhang, Z P; Zhilich, V; Zhulanov, V; Zupanc, A

    2016-01-01

    We report the result from the first search for $D^0$ decays to invisible final states. The analysis is performed on a data sample of 924 $\\rm{fb}^{-1}$ collected at and near the $\\Upsilon(4S)$ and $\\Upsilon(5S)$ resonances with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The absolute branching fraction is determined using an inclusive $D^0$ sample, obtained by fully reconstructing the rest of the particle system including the other charmed particle. No significant signal yield is observed and an upper limit of $9.4\\times 10^{-5}$ is set on the branching fraction of $D^0$ to invisible final states at 90\\% confidence level.

  19. Effects of Aftermarket Control Technologies on Gas and Particle Phase Oxidative Potential from Diesel Engine Emissions

    Science.gov (United States)

    Particulate matter (PM) originating from diesel combustion is a public health concern due to its association with adverse effects on respiratory and cardiovascular diseases and lung cancer. This study investigated emissions from three stationary diesel engines (gensets) with var...

  20. Trace gas and particle emissions from domestic and industrial biofuel use and garbage burning in central Mexico

    Directory of Open Access Journals (Sweden)

    T. J. Christian

    2010-01-01

    Full Text Available In central Mexico during the spring of 2007 we measured the initial emissions of 12 gases and the aerosol speciation for elemental and organic carbon (EC, OC, anhydrosugars, Cl, NO3, and 20 metals from 10 cooking fires, four garbage fires, three brick making kilns, three charcoal making kilns, and two crop residue fires. Global biofuel use has been estimated at over 2600 Tg/y. With several simple case studies we show that cooking fires can be a major, or the major, source of several gases and fine particles in developing countries. Insulated cook stoves with chimneys were earlier shown to reduce indoor air pollution and the fuel use per cooking task. We confirm that they also reduce the emissions of VOC pollutants per mass of fuel burned by about half. We did not detect HCN emissions from cooking fires in Mexico or Africa. Thus, if regional source attribution is based on HCN emissions typical for other types of biomass burning (BB, then biofuel use and total BB will be underestimated in much of the developing world. This is also significant because cooking fires are not detected from space. We estimate that ~2000 Tg/y of garbage are generated globally and about half may be burned, making this a commonly overlooked major global source of emissions. We estimate a fine particle emission factor (EFPM2.5 for garbage burning of ~10.5±8.8 g/kg, which is in reasonable agreement with very limited previous work. We observe large HCl emission factors in the range 2–10 g/kg. Consideration of the Cl content of the global waste stream suggests that garbage burning may generate as much as 6–9 Tg/yr of HCl, which would make it a major source of this compound. HCl generated by garbage burning in dry environments may have a relatively greater atmospheric impact than HCl generated in humid areas. Garbage burning PM2.5 was found to contain levoglucosan and K in concentrations similar to those for

  1. Trace gas and particle emissions from domestic and industrial biofuel use and garbage burning in central Mexico

    Directory of Open Access Journals (Sweden)

    T. J. Christian

    2009-04-01

    Full Text Available In central Mexico during the spring of 2007 we measured the initial emissions of 12 gases and the aerosol speciation for elemental and organic carbon (EC, OC, anhydrosugars, Cl-, NO3-, and 20 metals from 10 cooking fires, four garbage fires, three brick making kilns, three charcoal making kilns, and two crop residue fires. Biofuel use has been estimated at over 2600 Tg/y. With several simple case studies we show that cooking fires can be a major, or the major, source of several gases and fine particles in developing countries. Insulated cook stoves with chimneys were earlier shown to reduce indoor air pollution and the fuel use per cooking task. We confirm that they also reduce the emissions of VOC pollutants per mass of fuel burned by about half. We did not detect HCN emissions from cooking fires in Mexico or Africa. Thus, if regional source attribution is based on HCN emissions typical for other types of biomass burning (BB, then biofuel use and total BB will be underestimated in much of the developing world. This is also significant because cooking fires are not detected from space. We estimate that 2000 Tg/y of garbage are generated and about half may be burned, making this a commonly overlooked major global source of emissions. We estimate a fine particle emission factor (EFPM2.5 for garbage burning of ~10±5 g/kg, which is in reasonable agreement with very limited previous work. We observe large HCl emission factors in the range 2–10 g/kg. Consideration of the Cl content of the global waste stream suggests that garbage burning may generate as much as 6–9 Tg/yr of HCl, which would make it a major source of this compound. HCl generated by garbage burning in dry environments may have a relatively greater atmospheric impact than HCl generated in humid areas. Garbage burning PM2.5 was found to contain levoglucosan and K in concentrations similar to those for biomass burning, so it could

  2. Study of Deformation Effects in the Charged Particle Emission from 46Ti

    CERN Document Server

    Brekiesz, M; Maj, A; Kmiecik, M; Beck, C; Bednarczyk, P; Grebosz, J; Haas, F; Meczynski, W; Rauch, V; Rousseau, M; Zafra, A S; Styczen, J; Thummerer, S; Zieblinski, M; Zuber, K

    2004-01-01

    The 46Ti compound nucleus, as populated by the fusion-evaporation reaction 27Al + 19F at the bombarding energy of 144 MeV, has been investigated by charged particle spectroscopy using the multidetector array ICARE at the VIVITRON tandem facility of the IReS (Strasbourg). The light charged particles have been measured in coincidence with evaporation residues. The CACARIZO code, a Monte Carlo implementation of the statistical-model code CASCADE, has been used to calculate the spectral shapes of evaporated alpha-particles which are compared with the experimental spectra. This comparison indicates the possible signature of large deformations of the compound nucleus.

  3. Factors governing particle number emissions in a waste-to-energy plant.

    Science.gov (United States)

    Ozgen, Senem; Cernuschi, Stefano; Giugliano, Michele

    2015-05-01

    Particle number concentration and size distribution measurements were performed on the stack gas of a waste-to-energy plant which co-incinerates municipal solid waste, sewage sludge and clinical waste in two lines. Average total number of particles was found to be 4.0·10(5)cm(-3) and 1.9·10(5)cm(-3) for the line equipped with a wet flue gas cleaning process and a dry cleaning system, respectively. Ultrafine particles (dpwaste feed and the municipal solid waste co-incineration with sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Joint measurements of black carbon and particle mass for heavy-duty diesel vehicles using a portable emission measurement system

    Science.gov (United States)

    Zheng, Xuan; Wu, Ye; Zhang, Shaojun; Baldauf, Richard W.; Zhang, K. Max; Hu, Jingnan; Li, Zhenhua; Fu, Lixin; Hao, Jiming

    2016-09-01

    The black carbon (BC) emitted from heavy-duty diesel vehicles (HDDVs) is an important source of urban atmospheric pollution and creates strong climate-forcing impacts. The emission ratio of BC to total particle mass (PM) (i.e., BC/PM ratio) is an essential variable used to estimate total BC emissions from historical PM data; however, these ratios have not been measured using portable emission measurement systems (PEMS) in order to obtain real-world measurements over a wide range of driving conditions. In this study, we developed a PEMS platform by integrating two Aethalometers and an electric low pressure impactor to realize the joint measurement of real-world BC and PM emissions for ten HDDVs in China. Test results showed that the average BC/PM ratio for five HDDVs equipped with mechanical fuel injection (MI) engines was 0.43 ± 0.06, significantly lower (P engines (0.56 ± 0.12). Traffic conditions also affected the BC/PM ratios with higher ratios on freeway routes than on local roads. Furthermore, higher ratios were observed for HDDVs equipped with EI engines than for the MI engines for the highway and local road routes. With an operating mode binning approach, we observed that the instantaneous BC/PM ratios of EI engine vehicles were above those of the MI engine vehicles in all operating modes except for the braking mode (i.e., Bin 0). Therefore, the complex impacts from engine technology and traffic conditions on BC/PM ratios should be carefully considered when estimating real-world BC emissions from HDDVs based on overall PM emissions data.

  5. The effect of dynamic operating conditions on nano-particle emissions from a light-duty diesel engine applicable to prime and auxiliary machines on marine vessels

    Directory of Open Access Journals (Sweden)

    Hyungmin Lee

    2012-12-01

    Full Text Available This study presents the nano-sized particle emission characteristics from a small turbocharged common rail diesel engine applicable to prime and auxiliary machines on marine vessels. The experiments were conducted under dynamic engine operating conditions, such as steady-state, cold start, and transient conditions. The particle number and size distributions were analyzed with a high resolution PM analyzer. The diesel oxidation catalyst (DOC had an insignificant effect on the reduction in particle number, but particle number emissions were drastically reduced by 3 to 4 orders of magnitude downstream of the diesel particulate filter (DPF at various steady conditions. Under high speed and load conditions, the particle filtering efficiency was decreased by the partial combustion of trapped particles inside the DPF because of the high exhaust temperature caused by the increased particle number concentration. Retarded fuel injection timing and higher EGR rates led to increased particle number emissions. As the temperature inside the DPF increased from 25 °C to 300 °C, the peak particle number level was reduced by 70% compared to cold start conditions. High levels of nucleation mode particle generation were found in the deceleration phases during the transient tests.

  6. Application of Gauss's law space-charge limited emission model in iterative particle tracking method

    Energy Technology Data Exchange (ETDEWEB)

    Altsybeyev, V.V., E-mail: v.altsybeev@spbu.ru; Ponomarev, V.A.

    2016-11-01

    The particle tracking method with a so-called gun iteration for modeling the space charge is discussed in the following paper. We suggest to apply the emission model based on the Gauss's law for the calculation of the space charge limited current density distribution using considered method. Based on the presented emission model we have developed a numerical algorithm for this calculations. This approach allows us to perform accurate and low time consumpting numerical simulations for different vacuum sources with the curved emitting surfaces and also in the presence of additional physical effects such as bipolar flows and backscattered electrons. The results of the simulations of the cylindrical diode and diode with elliptical emitter with the use of axysimmetric coordinates are presented. The high efficiency and accuracy of the suggested approach are confirmed by the obtained results and comparisons with the analytical solutions.

  7. Loop heating by D.C. electric current and electromagnetic wave emissions simulated by 3-D EM particle zone

    Science.gov (United States)

    Sakai, J. I.; Zhao, J.; Nishikawa, K.-I.

    1994-01-01

    We have shown that a current-carrying plasma loop can be heated by magnetic pinch driven by the pressure imbalance between inside and outside the loop, using a 3-dimensional electromagnetic (EM) particle code. Both electrons and ions in the loop can be heated in the direction perpendicular to the ambient magnetic field, therefore the perpendicular temperature can be increased about 10 times compared with the parallel temperature. This temperature anisotropy produced by the magnetic pinch heating can induce a plasma instability, by which high-frequency electromagnetic waves can be excited. The plasma current which is enhanced by the magnetic pinch can also excite a kinetic kink instability, which can heat ions perpendicular to the magnetic field. The heating mechanism of ions as well as the electromagnetic emission could be important for an understanding of the coronal loop heating and the electromagnetic wave emissions from active coronal regions.

  8. Generation rates and emission factors of particulate matter and particle-bound polycyclic aromatic hydrocarbons of incense sticks.

    Science.gov (United States)

    Lung, Shih-Chun Candice; Hu, Shu-Chuan

    2003-02-01

    The generation rates and emission factors of particulate matter and associated polycyclic aromatic hydrocarbons (PAHs) from incense burning were assessed in a laboratory setting. The differences among different segments of the same stick, among different sticks of the same kind of incense, and between two kinds of manually made Chih-Chen incense sticks (A and B) were evaluated. Joss sticks were burned inside a 44 cm long elutriator; personal environmental monitors fitted into the top of the elutriator were used to take PM2.5 and PM10 samples of incense smoke. Samples were analyzed for PAHs by gas chromatography-flame ionization Detector. It was found that particle and associated PAHs were generated approximately at 561 microg/min (geometric standard deviation (GSD) = 1.1) and 0.56 microg/min (GSD = 1.1) from Incense A, and at 661 microg/min (GSD = 1.7) and 0.46 microg/min (GSD = 1.3) from Incense B, respectively. One gram of Incense A emitted about 19.8 mg (GSD = 1.1) particulate matter and 17.1 microg (GSD = 1.2) particulate-phase PAHs, while one gram of Incense B produced around 43.6 mg (GSD = 1.1) of particles and 25.2 microg (GSD = 1.2) of particle-bound PAHs. There were significant differences in emissions between Incenses A and B, although they belong to the same class of incense. A 10-20% variability in emissions was observed in the main part of the manually produced stick, and a larger variation was found at both tips of the combustible part.

  9. Experimental Investigation of Performance and emission characteristics of Various Nano Particles with Bio-Diesel blend on Di Diesel Engine

    Science.gov (United States)

    Karthik, N.; Goldwin Xavier, X.; Rajasekar, R.; Ganesh Bairavan, P.; Dhanseelan, S.

    2017-05-01

    Present study provides the effect of Zinc Oxide (ZnO) and Cerium Oxide (CeO2) nanoparticles additives on the Performance and emission uniqueness of Jatropha. Jatropha blended fuel is prepared by the emulsification technique with assist of mechanical agitator. Nano particles (Zinc Oxide (ZnO)) and Cerium Oxide (CeO2)) mixed with Jatropha blended fuel in mass fraction (100 ppm) with assist of an ultrasonicator. Experiments were conducted in single cylinder constant speed direct injection diesel engine for various test fuels. Performance results revealed that Brake Thermal Efficiency (BTE) of Jatropha blended Cerium Oxide (B20CE) is 3% and 11% higher than Jatropha blended zinc oxide (B20ZO) and Jatropha blended fuel (B20) and 4% lower than diesel fuel (D100) at full load conditions. Emission result shows that HC and CO emissions of Jatropha blended Cerium Oxide (B20CE) are (6%, 22%, 11% and 6%, 15%, 12%) less compared with Jatropha blended Zinc Oxide (B20ZO), diesel (D100) and Jatropha blended fuel (B20) at full load conditions. NOx emissions of Jatropha blended Cerium Oxide is 1 % higher than diesel fuel (D100) and 2% and 5% lower than Jatropha blended Zinc Oxide, and jatropha blended fuel.

  10. Emission of spherical cesium-bearing particles from an early stage of the Fukushima nuclear accident.

    Science.gov (United States)

    Adachi, Kouji; Kajino, Mizuo; Zaizen, Yuji; Igarashi, Yasuhito

    2013-01-01

    The Fukushima nuclear accident released radioactive materials into the environment over the entire Northern Hemisphere in March 2011, and the Japanese government is spending large amounts of money to clean up the contaminated residential areas and agricultural fields. However, we still do not know the exact physical and chemical properties of the radioactive materials. This study directly observed spherical Cs-bearing particles emitted during a relatively early stage (March 14-15) of the accident. In contrast to the Cs-bearing radioactive materials that are currently assumed, these particles are larger, contain Fe, Zn, and Cs, and are water insoluble. Our simulation indicates that the spherical Cs-bearing particles mainly fell onto the ground by dry deposition. The finding of the spherical Cs particles will be a key to understand the processes of the accident and to accurately evaluate the health impacts and the residence time in the environment.

  11. Oxidation Products of Biogenic Emissions Contribute to Nucleation of Atmospheric Particles

    CERN Document Server

    Riccobono, Francesco; Baltensperger, Urs; Worsnop, Douglas R; Curtius, Joachim; Carslaw, Kenneth S; Wimmer, Daniela; Wex, Heike; Weingartner, Ernest; Wagner, Paul E; Vrtala, Aron; Viisanen, Yrjö; Vaattovaara, Petri; Tsagkogeorgas, Georgios; Tomé, Antonio; Stratmann, Frank; Stozhkov, Yuri; Spracklen, Dominick V; Sipilä, Mikko; Praplan, Arnaud P; Petäjä, Tuukka; Onnela, Antti; Nieminen, Tuomo; Mathot, Serge; Makhmutov, Vladimir; Lehtipalo, Katrianne; Laaksonen, Ari; Kvashin, Alexander N.; Kürten, Andreas; Kupc, Agnieszka; Keskinen, Helmi; Kajos, Maija; Junninen, Heikki; Hansel, Armin; Franchin, Alessandro; Flagan, Richard C; Ehrhart, Sebastian; Duplissy, Jonathan; Dunne, Eimear M; Downard, Andrew; David, André; Breitenlechner, Martin; Bianchi, Federico; Amorim, Antonio; Almeida, João; Rondo, Linda; Ortega, Ismael K; Dommen, Josef; Scott, Catherine E; Vrtala, Aron; Santos, Filipe D; Schallhart, Simon; Seinfeld, John H; Sipila, Mikko; Donahue, Neil M; Kirkby, Jasper; Kulmala, Markku

    2014-01-01

    Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations.

  12. Analysis of charged particle emission sources and coalescence in E/A=61 (MeVAr)-Ar-36+Al-27, Sn-112 and Sn-124 collisions

    NARCIS (Netherlands)

    Avdeichikov, [No Value; Ghetti, R; Helgesson, J; Jakobsson, B; Golubev, P; Colonna, N; Wilschut, HW; Avdeitchikov, V.

    2004-01-01

    Single-particle kinetic energy spectra and two-particle small angle correlations of protons (p), deuterons (d) and tritons (t) have been measured simultaneously in 61 A MeV Ar-36 + Al-27, Sn-112 and Sn-124 collisions. Characteristics of the emission sources have been derived from a "source identific

  13. The Propagation of de Broglie Waves and Its Refraction in Rindler Space- The Possibility of Particle Emission from Classical Black Holes

    CERN Document Server

    Mitra, Soma

    2015-01-01

    In this article we have studied the propagation of matter waves in Rindler space. We have also developed a formalism to obtained the space dependent refractive index for de Broglie waves associated with a particle and shown the possibility of particle emission from the event horizon of classical black holes, when observed from a uniformly accelerated frame.

  14. Secondary electron emission from a charged spherical dust particle due to electron incidence according to OML model

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, Y., E-mail: tomita@swip.ac.cn [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China); Huang, Z.H.; Pan, Y.D. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China); Kawamura, G. [National Institute for Fusion Science, Toki 509-5292 (Japan); Yan, L.W. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China)

    2015-08-15

    Effect of secondary electron emission (SEE) current to dust charging and influence to forces on a dust particle are studied according to the orbital motion limited (OML) model. As higher electron temperature increases the SEE current, the negative dust charge decreases. As a result, the ion friction force on the dust particle decreases. The critical electron temperatures without the dust charge are 75.1, 70.3 and 55.9 eV for graphite and are 31.3, 30.4 and 27.1 eV for tungsten to the temperature ratio T{sub i}/T{sub e} = 0.1, 1.0 and 10.0, respectively. At the critical electron temperature, there is no ion scattering force but the ion absorption force remains finite.

  15. Search for non-standard, rare or invisible decays of the Higgs boson with the ATLAS detector

    CERN Document Server

    Thompson, Paul; The ATLAS collaboration

    2017-01-01

    Some theories predict Lepton Flavour Violating decays of the Higgs boson, while other predict enhanced decay rates in rare modes like Z-photon, J/Psi-photon and Phi-photon or into invisible particles. Such decays are searched for using about 36 fb-1 of p-p collisions at 13 TeV

  16. Fast particle-driven ion cyclotron emission (ICE) in tokamak plasmas and the case for an ICE diagnostic in ITER

    CERN Document Server

    McClements, K G; Dendy, R O; Carbajal, L; Chapman, S C; Cook, J W S; Harvey, R W; Heidbrink, W W; Pinches, S D

    2014-01-01

    Fast particle-driven waves in the ion cyclotron frequency range (ion cyclotron emission or ICE) have provided a valuable diagnostic of confined and escaping fast ions in many tokamaks. This is a passive, non-invasive diagnostic that would be compatible with the high radiation environment of deuterium-tritium plasmas in ITER, and could provide important information on fusion {\\alpha}-particles and beam ions in that device. In JET, ICE from confined fusion products scaled linearly with fusion reaction rate over six orders of magnitude and provided evidence that {\\alpha}-particle confinement was close to classical. In TFTR, ICE was observed from super-Alfv\\'enic {\\alpha}-particles in the plasma edge. The intensity of beam-driven ICE in DIII-D is more strongly correlated with drops in neutron rate during fishbone excitation than signals from more direct beam ion loss diagnostics. In ASDEX Upgrade ICE is produced by both super-Alfv\\'enic DD fusion products and sub-Alfv\\'enic deuterium beam ions.

  17. Composite-particle emission in the reaction p+Au at 2.5 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Letourneau, A.; Bohm, A.; Galin, J.; Lott, B.; Peghaire, A. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Enke, M.; Herbach, C.M.; Hilscher, D.; Jahnke, U.; Tishchenko, V. [Hahn Meitner Institute, Berlin (Germany); Filges, D.; Goldenbaum, F.; Neef, R.D.; Nunighoff, K.; Paul, N.; Sterzenbach, G. [Institut fur Kernphysik, Julich (Germany); Pienkowski, L. [Warsaw Universitaire, Heavy Ion Lab. (Poland); Toke, J.; Schroder, U. [Rochester, University, New York (United States)

    2002-06-01

    The emission of composite-particles is studied in the reaction p+Au at E{sub p} = 2.5 GeV, in addition to neutrons and protons. Most particle energy spectra feature an evaporation spectrum superimposed on an exponential high-energy, non-statistical component. Comparisons are first made with the predictions by a two-stage hybrid reaction model, where an intra-nuclear cascade (INC) simulation is followed by a statistical evaporation process. The high-energy proton component is identified as product of the fast pre-equilibrium INC, since it is rather well reproduced by the INCL2.0 intra-nuclear cascade calculations simulating the first reaction stage. The low-energy spectral components are well understood in terms of sequential particle evaporation from the hot nuclear target remnants of the fast INC. Evaporation is modeled using the statistical code GEMINI. Implementation of a simple coalescence model in the INC code can provide a reasonable description of the multiplicities of high-energy composite particles such as {sup 2-3}H and {sup 3}He. However, this is done at the expense of {sup 1}H which then fails to reproduce the experimental energy spectra. (authors)

  18. Observation of solar high energy gamma and X-ray emission and solar energetic particles

    CERN Document Server

    Struminsky, Alexei

    2015-01-01

    We considered 18 solar flares observed between June 2010 and July 2012, in which high energy >100 MeV {\\gamma}-emission was registered by the Large Area Telescope (LAT) aboard FermiGRO. We examined for these {\\gamma}-events soft X-ray observations by GOES, hard X-ray observations by the Anti-Coincidence Shield of the SPectrometer aboard INTEGRAL (ACS SPI) and the Gamma-Ray burst Monitor (GBM) aboard FermiGRO. Hard X-ray and {\\pi}0-decay {\\gamma}-ray emissions are used as tracers of electron and proton acceleration, respectively. Bursts of hard X-ray were observed by ACS SPI during impulsive phase of 13 events. Bursts of hard X-ray >100 keV were not found during time intervals, when prolonged hard {\\gamma}-emission was registered by LAT/FermiGRO. Those events showing prolonged high-energy gamma-ray emission not accompanied by >100 keV hard X-ray emission are interpreted as an indication of either different acceleration processes for protons and electrons or as the presence of a proton population accelerated du...

  19. Direct evidence for coastal iodine particles from Laminaria macroalgae – linkage to emissions of molecular iodine

    Directory of Open Access Journals (Sweden)

    G. McFiggans

    2004-01-01

    Full Text Available Renewal of ultrafine aerosols in the marine boundary layer may lead to repopulation of the marine distribution and ultimately determine the concentration of cloud condensation nuclei (CCN. Thus the formation of nanometre-scale particles can lead to enhanced scattering of incoming radiation and a net cooling of the atmosphere. The recent demonstration of the chamber formation of new particles from the photolytic production of condensable iodine-containing compounds from diiodomethane (CH2I2, (O'Dowd et al., 2002; Kolb, 2002; Jimenez et al., 2003a; Burkholder and Ravishankara, 2003, provides an additional mechanism to the gas-to-particle conversion of sulphuric acid formed in the photo-oxidation of dimethylsulphide for marine aerosol repopulation. CH2I2 is emitted from seaweeds (Carpenter et al., 1999, 2000 and has been suggested as an initiator of particle formation. We demonstrate here for the first time that ultrafine iodine-containing particles are produced by intertidal macroalgae exposed to ambient levels of ozone. The particle composition is very similar both to those formed in the chamber photo-oxidation of diiodomethane and in the oxidation of molecular iodine by ozone. The particles formed in all three systems are similarly aspherical. When small, those formed in the molecular iodine system swell only moderately when exposed to increased humidity environments, and swell progressively less with increasing size; this behaviour occurs whether they are formed in dry or humid environments, in contrast to those in the CH2I2 system. Direct coastal boundary layer observations of molecular iodine, ultrafine particle production and iodocarbons are reported. Using a newly measured molecular iodine photolysis rate, it is shown that, if atomic iodine is involved in the observed particle bursts, it is of the order of at least 1000 times more likely to result from molecular iodine photolysis than diiodomethane photolysis. A hypothesis for molecular

  20. A Nano-satellite Mission to Study Charged Particle Precipitation from the Van Allen Radiation Belts caused due to Seismo-Electromagnetic Emissions

    CERN Document Server

    Sivadas, Nithin; Kannapan, Deepti; Yalamarthy, Ananth Saran; Dhiman, Ankit; Bhagoji, Arjun; Shankar, Athreya; Prasad, Nitin; Ramachandran, Harishankar; Koilpillai, R David

    2014-01-01

    In the past decade, several attempts have been made to study the effects of seismo-electromagnetic emissions - an earthquake precursor, on the ionosphere and the radiation belts. The IIT Madras nano-satellite (IITMSAT) mission is designed to make sensitive measurements of charged particle fluxes in a Low Earth Orbit to study the nature of charged particle precipitation from the Van Allen radiation belts caused due to such emissions. With the Space-based Proton Electron Energy Detector on-board a single nano-satellite, the mission will attempt to gather statistically significant data to verify possible correlations with seismo-electromagnetic emissions before major earthquakes.

  1. Titanium dioxide (TiO2) fine particle capture and BVOC emissions of Betula pendula and Betula pubescens at different wind speeds

    Science.gov (United States)

    Räsänen, Janne V.; Leskinen, Jari T. T.; Holopainen, Toini; Joutsensaari, Jorma; Pasanen, Pertti; Kivimäenpää, Minna

    2017-03-01

    Trees are known to affect air quality by capturing a remarkable amount of particles from the atmosphere. However, the significance of trees in removing very fine particles (diameter less than 0.5 μm) is not well understood. We determined particle capture efficiency (Cp) of two birch species: Betula pendula and Betula pubescens by using inert titanium dioxide fine particles (TiO2, geometric mean diameter 0.270 μm) at three wind speeds (1, 3 and 6 ms-1) in a wind tunnel. Capture efficiencies were determined by measuring densities of TiO2 particles on leaf surfaces by scanning electron microscopy. In addition, the particle intake into an inner structure of leaves was studied by transmission electron microscopy. The effects of fine particle exposure and wind speed on emission rates of biogenic volatile organic compounds (BVOCs) were measured. Particles were captured (Cp) equally efficiently on foliage of B. pendula (0.0026 ± 0.0005) % and B. pubescens (0.0025 ± 0.0006) %. Increasing wind speed significantly decreased Cp. Increasing wind speed increased deposition velocity (Vg) on B. pendula but not on B. pubescens. Particles were deposited more efficiently on the underside of B. pendula leaves, whereas deposition was similar on the upper and under sides of B. pubescens leaves. TiO2 particles were found inside three of five B. pendula leaves exposed to particles at a wind speed of 1 ms-1 indicating that particles can penetrate into the plant structure. Emission rates of several mono-, homo- and sesquiterpenes were highest at a wind speed of 3 ms-1 in B. pendula. In B. pubescens, emission rates of a few monoterpenes and nonanal decreased linearly with wind speed, but emission rates of sesquiterpenes were lowest at 3 ms-1 and increased at 6 ms-1. Emission rates of a few green leaf volatile compounds increased with increasing wind speed in both species. The results of this study suggest that the surface structure of trees is less important for capturing particles with

  2. Heidegger’s phenomenology of the invisible

    Directory of Open Access Journals (Sweden)

    Andrzej SERAFIN

    2016-12-01

    Full Text Available Martin Heidegger has retrospectively characterized his philosophy as “phenomenology of the invisible”. This paradoxical formula suggests that the aim of his thinking was to examine the origin of the phenomena. Furthermore, Heidegger has also stated that his philosophy is ultimately motivated by a theological interest, namely the question of God’s absence. Following the guiding thread of those remarks, this essay analyzes the essential traits of Heidegger’s thought by interpreting them as an attempt to develop a phenomenology of the invisible. Heidegger’s attitude towards physics and metaphysics, his theory of truth, his reading of Aristotle, his concept of Dasein, his understanding of nothingness are all situated within the problematic context of the relation between the invisible and the revealed. Heidegger’s thought is thereby posited at the point of intersection of phenomenology, ontology, and theology.

  3. Invisible Assets of Uneven-Age Associations

    Directory of Open Access Journals (Sweden)

    Krapivina L. A.

    2014-01-01

    Full Text Available The problem of insufficient usage of research results devoted to the development and teaching a person in multi-aged in pedagogical theory and practice is considered. The occurrence of “invisible assets” as a phenomenon of human activity results is also reviewed. These results show the synergic effect that considerably exceeds the index relative to the effort sum of separate components. The results of the emergent effect of invisible assets manifestation in multi-aged unions studied in Russian pedagogical science are represented. The systemic factors defining the magnitude, power and limit of educative potential of a multi-aged union are singled out. The necessity of using the results of rich Russian pedagogical experience of G. V. Radetskiy, S. T. Shatskiy, A. S. Makarenko, I. P. Ivanov, V. P. Krapivin and their followers of the 21st century in studying social development of adolescents based on the historical-genetic analysis is shown in the paper.

  4. Shifting Contexts in Invisible Computing Environments

    Energy Technology Data Exchange (ETDEWEB)

    McGee, David R.; Pavel, Misha; Cohen, Philip R.; A K Dey, P Ljungstrand, A Schmidt.

    2001-03-30

    Invisible computing systems are highly context-dependent. Consequently, the influence that language has on contextual interpretation cannot be ignored by such systems. Rather, once language and other forms of human action are perceived by a system, its interpretative processes will of necessity be context-dependent. As an example, we illustrate how people simply and naturally create new contexts for interpretation by creating new names and referring expressions. We then describe Rasa, a mixed-reality system that invisibly observes and understands how users in a military command post create such contexts as part of the process of maintaining situational awareness. Rasa augments both the commander?s map and the Post-it notes pasted on it, which represent units in the field, with multimodal language, thereby allowing paper-based tools to interact with digital information. Finally, we argue that architectures for such context-aware systems must reduce the inherent ambiguity and uncertainty through fusion and other means.

  5. Digital/Commercial (In)visibility

    DEFF Research Database (Denmark)

    Leander, Anna

    2016-01-01

    an argument demonstrating specifically how digital and commercial logics characterize the aesthetic, circulatory, and infrastructuring practices re-producing the regime of (in)visibility. It shows that digital/commercial logics are at the heart of the combinatorial marketing of multiple, contradictory images......This article explores one aspect of digital politics, the politics of videos and more spe- cifically of DAESH recruitment videos. It proposes a practice theoretical approach to the politics of DAESH recruitment videos focused on the re-production of regimes of (in)visibility. The article develops...... on the internet. The theoretical and political cost of overlooking these digital and commercial characteristics of DAESH visibility practices are high. It perpetuates misconceptions of how the videos work and what their politics are and it reinforces the digital Orientalism/Occidentalism in which...

  6. Can invisible watermarks resolve rightful ownerships?

    Science.gov (United States)

    Craver, Scott A.; Memon, Nasir D.; Yeo, Boon-Lock; Yeung, Minerva M.

    1997-01-01

    Digital watermarks have been proposed in recent literature as the means for copyright protection of multimedia data. In this paper we address the capability of invisible watermarking schemes to resolve copyright ownerships. We will show that rightful ownerships cannot be resolved by current watermarking schemes alone. In addition, in the absence of standardization of watermarking procedures, anyone can claim ownership of any watermarked image. Specifically, we provide counterfeit watermarking schemes that can be performed on a watermarked image to allow multiple claims of rightful ownerships. We also proposed non-invertible watermarking schemes in this paper and discuss in general the usefulness of digital watermarks in identifying the rightful copyright owners. The results, coupled with the recent attacks on some image watermarks, further imply that we have to carefully re-think our approaches to invisible watermarking of images, and re- evaluate the promises, applications and limitations of such digital means of copyright protection.

  7. COMBINE VISIBLE AND INVISIBLE SECURE DIGITAL MESSAGE

    Directory of Open Access Journals (Sweden)

    A.C.Suthar,

    2010-07-01

    Full Text Available The digital watermarking is used to protect the intellectual property rights in the multimedia field. It consists of algorithms which embed in digital multimedia data such as video, image or audio, an invisible information related to its owner and its. The invisible watermark is embed in such a way that alternations made to the pixelvalue are perceptually not noticed and it can be recovered only with appropriate decoding mechanism. In order to protect the watermarked data, a cryptographically secure pseudo-noise signal is needed. In this paper we propose a technique for generating a watermark signal which depends on the original by using hash functions and to improve the robustness turbo coding is applied.

  8. Temporal bone chondroblastoma totally invisible on MRI.

    Science.gov (United States)

    Hiraumi, Harukazu; Arakawa, Yoshiki; Yamamoto, Norio; Sakamoto, Tatsunori; Ito, Juichi

    2016-08-01

    We report a case of temporal bone chondroblastoma that was totally invisible on MRI. The patient was a 64-year-old man who presented with several months history of vertigo. The CT scan with bone window setting showed destruction of the temporomandibular joint, the floor of the middle cranial fossa, and the superior semicircular canal. Calcific foci were seen within the tumor. On MR imaging, the tumor, situating mainly medial to the temporomandibular joint, showed no signal on both T1- and T2-weighted images. The tumor was not enhanced with gadolinium. In summary, the tumor was totally signal negative or "invisible" on pre- and postcontrast T1- and T2-weighted images. The tumor was resected through transpetrosal - transzygomatic approach.

  9. Macroscopic Invisible Cloak for Visible Light

    CERN Document Server

    Zhang, Baile; Liu, Xiaogang; Barbastathis, George

    2011-01-01

    Invisibility cloaks, a subject that usually occurs in science fiction and myths, have attracted wide interest recently because of their possible realization. The biggest challenge to true invisibility is known to be the cloaking of a macroscopic object in the broad range of wavelengths visible to the human eye. Here we experimentally solve this problem by incorporating the principle of transformation optics into a conventional optical lens fabrication with low-cost materials and simple manufacturing techniques. A transparent cloak made of two pieces of calcite is created. This cloak is able to conceal a macroscopic object with a maximum height of 2 mm, larger than 3500 free-space-wavelength, inside a transparent liquid environment. Its working bandwidth encompassing red, green and blue light is also demonstrated.

  10. Engineered emissivity of textile fabrics by the inclusion of ceramic particles.

    Science.gov (United States)

    Pooley, Matthew A; Anderson, David M; Beckham, Haskell W; Brennan, James F

    2016-05-16

    Composite textile materials, created from a blend of different fibers, have long been used to engineer the properties and performance of fabrics to combine comfort with functionality, such as to create materials with differing optical properties. Some changes to the optical properties of materials in the infrared are subtle and difficult to measure. We present a measurement technique, experimental apparatus, and associated data analysis procedure for detecting small changes in the emissivity of fabrics in the mid-infrared wavelength range (7.5-14 µm). Using this technique, we demonstrate that the emissivity of polyester fabric can be engineered controllably via the inclusion of ceramic microparticles within the fabric fibers.

  11. Metamaterials and the mathematical Science of invisibility

    CERN Document Server

    Diatta, Andre; Nicolet, Andre; Zolla, Frederic

    2012-01-01

    In this chapter, we review some recent developments in the field of photonics: cloaking, whereby an object becomes invisible to an observer, and mirages, whereby an object looks like another one (say, of a different shape). Such optical illusions are made possible thanks to the advent of metamaterials, which are new kinds of composites designed using the concept of transformational optics. Theoretical concepts introduced here are illustrated by finite element computations.

  12. An invisible wall put up by ghosts

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正>When I was a child, my grandmother would often tell me ghost stories. One of them was about an invisible wall that had been put up by ghosts.It was a winter night that was getting darker and darker, colder and colder. A lone farmer was driving his horse and cart along a country path. As he was getting close to his village, he could see the cemetery with the myriad tombs on both sides

  13. Effects of low concentration biodiesel blend application on modern passenger cars. Part 1: feedstock impact on regulated pollutants, fuel consumption and particle emissions.

    Science.gov (United States)

    Fontaras, Georgios; Kousoulidou, Marina; Karavalakis, Georgios; Tzamkiozis, Theodoros; Pistikopoulos, Panayotis; Ntziachristos, Leonidas; Bakeas, Evangelos; Stournas, Stamoulis; Samaras, Zissis

    2010-05-01

    Five biodiesels from different feedstocks (rapeseed, soy, sunflower, palm, and used fried oils) blended with diesel at 10% vol. ratio (B10), were tested on a Euro 3 common-rail passenger car. Limited effects (-2% to +4%) were observed on CO(2) emissions. CO and HC emissions increased between 10% and 25% on average, except at high speed - high power where emissions were too low to draw conclusions. NOx emissions increased by up to 20% for two out of the five blends, decreased by up to 15% for two other blends, and remained unchanged for one blend. Particulate matter (PM) was reduced for all blends by up to 25% and the reductions were positively correlated with the extent of biodiesel saturation. PM reductions are associated with consistent reductions in non-volatile particle number. A variable behaviour in particle number is observed when volatile particles are also accounted.

  14. Primary gas- and particle-phase emissions and secondary organic aerosol production from gasoline and diesel off-road engines.

    Science.gov (United States)

    Gordon, Timothy D; Tkacik, Daniel S; Presto, Albert A; Zhang, Mang; Jathar, Shantanu H; Nguyen, Ngoc T; Massetti, John; Truong, Tin; Cicero-Fernandez, Pablo; Maddox, Christine; Rieger, Paul; Chattopadhyay, Sulekha; Maldonado, Hector; Maricq, M Matti; Robinson, Allen L

    2013-12-17

    Dilution and smog chamber experiments were performed to characterize the primary emissions and secondary organic aerosol (SOA) formation from gasoline and diesel small off-road engines (SOREs). These engines are high emitters of primary gas- and particle-phase pollutants relative to their fuel consumption. Two- and 4-stroke gasoline SOREs emit much more (up to 3 orders of magnitude more) nonmethane organic gases (NMOGs), primary PM and organic carbon than newer on-road gasoline vehicles (per kg of fuel burned). The primary emissions from a diesel transportation refrigeration unit were similar to those of older, uncontrolled diesel engines used in on-road vehicles (e.g., premodel year 2007 heavy-duty diesel trucks). Two-strokes emitted the largest fractional (and absolute) amount of SOA precursors compared to diesel and 4-stroke gasoline SOREs; however, 35-80% of the NMOG emissions from the engines could not be speciated using traditional gas chromatography or high-performance liquid chromatography. After 3 h of photo-oxidation in a smog chamber, dilute emissions from both 2- and 4-stroke gasoline SOREs produced large amounts of semivolatile SOA. The effective SOA yield (defined as the ratio of SOA mass to estimated mass of reacted precursors) was 2-4% for 2- and 4-stroke SOREs, which is comparable to yields from dilute exhaust from older passenger cars and unburned gasoline. This suggests that much of the SOA production was due to unburned fuel and/or lubrication oil. The total PM contribution of different mobile source categories to the ambient PM burden was calculated by combining primary emission, SOA production and fuel consumption data. Relative to their fuel consumption, SOREs are disproportionately high total PM sources; however, the vastly greater fuel consumption of on-road vehicles renders them (on-road vehicles) the dominant mobile source of ambient PM in the Los Angeles area.

  15. Characterization of particulate matter emissions from on-road gasoline and diesel vehicles using a soot particle aerosol mass spectrometer

    Science.gov (United States)

    Dallmann, T. R.; Onasch, T. B.; Kirchstetter, T. W.; Worton, D. R.; Fortner, E. C.; Herndon, S. C.; Wood, E. C.; Franklin, J. P.; Worsnop, D. R.; Goldstein, A. H.; Harley, R. A.

    2014-07-01

    Particulate matter (PM) emissions were measured in July 2010 from on-road motor vehicles driving through a highway tunnel in the San Francisco Bay area. A soot particle aerosol mass spectrometer (SP-AMS) was used to measure the chemical composition of PM emitted by gasoline and diesel vehicles at high time resolution. Organic aerosol (OA) and black carbon (BC) concentrations were measured during various time periods that had different levels of diesel influence, as well as directly in the exhaust plumes of individual heavy-duty (HD) diesel trucks. BC emission factor distributions for HD trucks were more skewed than OA distributions (N = 293), with the highest 10% of trucks accounting for 56 and 42% of total measured BC and OA emissions, respectively. OA mass spectra measured for HD truck exhaust plumes show cycloalkanes are predominate in exhaust OA emissions relative to saturated alkanes (i.e., normal and iso-paraffins), suggesting that lubricating oil rather than fuel is the dominant source of primary organic aerosol (POA) emissions in diesel vehicle exhaust. This finding is supported by the detection of trace elements such as zinc and phosphorus in the exhaust plumes of individual trucks. Trace elements were emitted relative to total OA at levels that are consistent with typical weight fractions of commonly used additives present in lubricating oil. A comparison of measured OA and BC mass spectra across various sampling periods revealed a high degree of similarity in OA and BC emitted by gasoline and diesel engines. This finding indicates a large fraction of OA in gasoline exhaust is lubricant-derived as well. The similarity in OA and BC mass spectra for gasoline and diesel engine exhaust is likely to confound ambient source apportionment efforts to determine contributions to air pollution from these two important sources.

  16. Invisible decays in Higgs boson pair production

    Science.gov (United States)

    Banerjee, Shankha; Batell, Brian; Spannowsky, Michael

    2017-02-01

    Observation of Higgs pair production is an important long term objective of the LHC physics program as it will shed light on the scalar potential of the Higgs field and the nature of electroweak symmetry breaking. While numerous studies have examined the impact of new physics on di-Higgs production, little attention has been given to the well-motivated possibility of exotic Higgs decays in this channel. Here we investigate the consequences of exotic invisible Higgs decays in di-Higgs production. We outline a search sensitive to such invisible decays in the b b ¯+ ET channel. We demonstrate that probing invisible branching ratios of order 10% during the LHC's high-luminosity run will be challenging, but in resonance enhanced di-Higgs production, this final state can become crucial to establish the existence of physics beyond the Standard Model at collider energies. We also briefly discuss the outlook for other exotic Higgs decay modes and the potential to observe such exotic decays in the di-Higgs channel.

  17. Diagnostic Signatures of Radio and HXR Emission on Particle Acceleration Processes in the Coma Cluster

    CERN Document Server

    Kuo, P H; Ip, W H; Kuo, Ping-Hung; Hwang, Chorng-Yuan; Ip, Wing-Huen

    2003-01-01

    We investigate theoretical models for the radio halo and hard X-ray (HXR) excess in the Coma galaxy cluster. Time-independent and time-dependent re-acceleration models for relativistic electrons have been carried out to study the formation of the radio halo and HXR excess. In these models, the relativistic electrons are injected by merger shocks and re-accelerated by ensuing violent turbulence. The effects of different Mach numbers of the merger shocks on the radio and HXR excess emission are also investigated. We adopt 6 $mu$G as the central magnetic field and reproduce the observed radio spectra via the synchrotron emission. We also obtain a central "plateau" in the radio spectral-index distribution, which have been observed in radio emission distribution. Our models can also produce the observed HXR excess emission via the inverse Compton scattering of the cosmic microwave background photons. We find that only the merger shocks with the Mach numbers around 1.6--2 can produce results in agreement with both ...

  18. OPEN BURNING OF AGRICULTURAL BIOMASS: PHYSICAL AND CHEMICAL PROPERTIES OF PARTICLE-PHASE EMISSIONS

    Science.gov (United States)

    This effort presents the physical and chemical characterization of PM2.5 emissions from simulated agricultural fires of surface residuals of two major grain crops, rice (Oryza sativa) and wheat (Triticum aestivum L). The O2 levels and CO/CO

  19. Measurement of Ozone Emission and Particle Removal Rates from Portable Air Purifiers

    Science.gov (United States)

    Mang, Stephen A.; Walser, Maggie L.; Nizkorodov, Sergey A.; Laux, John M.

    2009-01-01

    Portable air purifiers are popular consumer items, especially in areas with poor air quality. Unfortunately, most users of these air purifiers have minimal understanding of the factors affecting their efficiency in typical indoor settings. Emission of the air pollutant ozone (O[subscript 3]) by certain air purifiers is of particular concern. In an…

  20. Particle transport in a He-microchip plasma atomic emission system with an ultrasonic nebulizer for aqueous sample introduction

    Science.gov (United States)

    Oh, Joosuck; Lim, H. B.

    2008-11-01

    The transport efficiency of dried particles generated from an ultrasonic nebulizer (USN) was studied to improve the analytical performance of a lab-made, He-microchip plasma system, in which a quartz tube (~ 1 mm i.d.) was positioned inside the central channel of a poly(dimethylsiloxane) (PDMS) polymer chip. The polymer microchip plasma has the advantages of low cost, small size, easy handling and design, and self-ignition with long stabilization (> 24 h). However, direct introduction of aqueous solution into the microplasma for the detection of metals remains problematic due to plasma instability. In addition, the much smaller size of the system can cause signal suppression due to low transport efficiency. Therefore, knowledge of particle transport efficiency in this microplasma system is required to enhance the sensitivity and stability. The weight of transported particles in the range of 0.02 to 10 mg m - 3 was measured using a piezobalance with a precision of 0.4-17.8%, depending on the operating conditions. The significant effects of the USN operating conditions and the physical properties of the tubing, namely, length, inner diameter and surface characteristics, on the number of particles transported from the nebulizer to the microplasma were studied. When selected metals, such as Na, Mg and Pb, at a concentration of 5 mg L - 1 were nebulized, transported particles were obtained with a mass range of 0.5-5 mg m - 3 , depending on atomic weights. For application of the He-rf-microplasma, the atomic emission system was optimized by changing both the radio frequency (rf) power (60-200 W) and cooling temperature of the USN (- 12-9 °C). The limits of detection obtained for K, Na and Cu were 0.26, 0.22, and 0.28 mg L - 1 , respectively. These results confirmed the suitable stability and sensitivity of the He-rf-PDMS microchip plasma for application as an atomization source.

  1. Cosmological Implications of High-Energy Neutrino Emission from the Decay of Long-Lived Particle

    CERN Document Server

    Ema, Yohei; Moroi, Takeo

    2014-01-01

    We study cosmological scenario in which high-energy neutrinos are emitted from the decay of long-lived massive particles at the cosmic time later than the redshift of 10^6. The high-energy neutrino events recently observed by the IceCube experiment suggest a new source of high-energy cosmic-ray neutrinos; decay of a heavy particle can be one of the possibilities. We calculate the spectrum of the high-energy neutrinos emitted from the decay of long-lived particles, taking account of the neutrino scattering processes with background neutrinos. Then, we derive bounds on the scenario using the observation of high-energy cosmic-ray neutrino flux. We also study constraints from the spectral distortions of the cosmic microwave background, taking into account both the current (COBE/FIRAS) and future (PIXIE) bounds. In addition, we show that the PeV neutrinos observed by the IceCube experiment can originate from the decay of a massive particle with its mass as large as O(10^10 GeV).

  2. Emission characteristics of ultrafine particles and volatile organic compounds in a commercial printing center.

    Science.gov (United States)

    Betha, Raghu; Selvam, Valliappan; Blake, Donald R; Balasubramanian, Rajasekhar

    2011-11-01

    Laser printers are one of the common indoor equipment in schools, offices, and various other places. Laser printers have recently been identified as a potential source of indoor air pollution. This study examines the characteristics of ultrafine particles (UFPs, diameter commercial printing center. The results indicated that apart from the printer type, the age of printers, and the number of pages printed, the characteristics of UFPs emitted from printers also depend on indoor ventilation conditions. It was found that at reduced ventilation rates of indoor air, there was a rise in the number concentration of UFPs in the printing center. Interestingly, the contribution of UFPs to the total number of submicrometer-sized particles was observed to be higher at a sampling point far away from the printer than the one in the immediate vicinity of the printer. Black carbon (BC) measurements showed a good correlation (rs = 0.82) with particles in the size range of 100-560 nm than those with diameters less than 100 nm (rs = 0.33 for 50-100 nm, and rs = -0.19 for 5.6-50 nm particles). Measurements of VOCs in the printing center showed high levels of m-, o-, and p-xylene, styrene, and ethylbenzenes during peak hours of printing. Although toluene was found in higher levels, its concentration decreased during peak hours compared to those during nonoperating hours of the printing center.

  3. At CERN : exploring the invisible

    CERN Multimedia

    Rene Quinet

    1983-01-01

    Today, the two frontiers of the unknown are being push back to the infinity large to the infinity small...man probes the depth of matter and discovers the link between these two extremes ... dedicated to the studies of one of the frontiers of the universe, CERN, where since 1954 the European collaboration is set-up, brings together the equipments needed to elucidate the mysteries of the infinity small ... some 3400 technicians, workers, administrators and ingeneers help to operate the installations with about one hundred resident physicists ... 2000 scientific users from 160 outside universities exploit the site of learning ... Start with John Ellis at the blackboard. Schopper â€ワIf you look back in history...new discoveries lead to new applications, ex. electromagnetism lead to electric light, radio and tv of today.” Presentation of CERN using a edit showing many short shots of what’s going on at CERN. Animation of particles and forces. Aerial views. Scanning. Van der Meer, ACOL. SPS; UA1, UA2....

  4. Evaluating the dynamical characteristics of particle matter emissions in an open ore yard with industrial operation activities.

    Science.gov (United States)

    Cong, X C; Yang, G S; Qu, J H; Dai, M X

    2016-11-01

    A study to investigate the dynamical characteristics of particle matter emissions in a working open yard is conducted in Caofeidian Port of Hebei Province, China. The average diurnal concentrations of the total suspended particulate (TSP) matter and respirable particulate matter (PM10 and PM5) are monitored during the field measurement campaign. Sampling is performed at a regular interval at 8 monitoring stations in the yard with normal industrial activities. The average TSP, PM10 and PM5 concentrations range from 285 to 568, 198 to 423 and 189 to 330 μg.m-3 in the yard, respectively. The linear regression correlation coefficient of TSP/PM10 and TSP/PM5 is 0.95±0.01 and 0.88±0.02, respectively.By using the Spearman correlation method, the wind speed and relative humidity are both weakly correlated with the PM10 and PM5 concentrations according to the measurements. In addition, industrial operation activities, such as vehicular traffic in the yard and the loading time of stackers, are significantly positively correlated with the PM concentration. Using the multivariate regression method, the main parameters influencing the TSP concentration variations are integratedly analysed. The traffic volume is found to be a significant predictor of TSP concentration variation, with the smallest P value (Pindustrial activities in the yard is proposed. The dynamical emissions average 5.25x10(5) kg.year(-1) and EFD is evaluated to be 0.29 kg.(ton.day)(-1) during the measurement period. These outcomes have meaningful implications not only for understanding the dynamical characteristics of particle emissions in the working stockyard but also for implementing effective control measures at appropriate sites in the harbour area.

  5. Search for Invisible Decays of the Upsilon(1S) Resonance

    CERN Document Server

    Rubin, P; Adams, G S; Alexander, J P; Anderson, M; Aquines, O; Artuso, M; Asner, D M; Athar, S B; Besson, D; Blusk, S; Bonvicini, G; Briere, R A; Butt, J; Cassel, D G; Cawlfield, C; Cinabro, D; Coan, T E; Cronin-Hennessy, D; Cummings, J P; Danko, I; Dobbs, S; Duboscq, J E; Dubrovin, M; Ecklund, K M; Edwards, K W; Ehrlich, R; Eisenstein, B I; Ernst, J; Ferguson, T; Fields, L; Galik, R S; Gao, K Y; Gao, Y S; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; He, Q; Heltsley, B K; Hertz, D; Hietala, J; Hu, D; Huang, G S; Insler, J; Jones, C D; Kandaswamy, J; Karliner, I; Kim, D; Klein, T; Kreinick, D L; Kubota, Y; Kuznetsov, V E; Lang, B W; Li, J; Li, Z; Lincoln, A; Love, W; Lowrey, N; López, A; Mahlke-Krüger, H; Mehrabyan, S S; Menaa, N; Metreveli, Z V; Miller, D H; Mitchell, R E; Mountain, R; Moziak, B; Muramatsu, H; Méndez, H; Naik, P; Napolitano, J; Nisar, S; Onyisi, P U E; Park, C S; Patel, R; Patterson, J R; Pavlunin, V; Pedlar, T K; Peterson, D; Pivarski, J; Poling, R; Potlia, V; Ramírez, J; Randrianarivony, K; Riley, D; Rosner, J L; Ryd, A; Sadoff, A J; Sanghi, B; Savinov, V; Schwarthoff, H; Scott, A W; Selen, M; Seth, K K; Severini, H; Shepherd, M R; Shi, X; Shipsey, I P J; Sia, R; Skwarnicki, T; Smith, A; Stone, S; Stroiney, S; Sun, W M; Tatishvili, G T; Thorndike, E H; Tomaradze, A G; Vogel, H; Wang, J C; Watkins, M E; White, E J; Wilksen, T; Wiss, J; Xin, B; Yang, F; Yelton, J; Zhang, K; Zweber, P; al, et

    2007-01-01

    We present a measurement of the branching fraction of invisible Upsilon(1S) decays, using 1.2 fb^{-1} of data collected at the Upsilon(2S) resonance with the CLEO III detector at CESR. After subtracting expected backgrounds from events that pass selection criteria for invisible Upsilon(1S) decay in Upsilon(2S) -> pi+ pi- Upsilon(1S), we deduce a 90% C.L. upper limit of B[Upsilon(1S) -> invisible] < 0.39%.

  6. What is the invisible web? A crawler perspective

    OpenAIRE

    Arroyo, Natalia

    2004-01-01

    The invisible Web, also known as the deep Web or dark matter, is an important problem for Webometrics due to difficulties of conceptualization and measurement. The invisible Web has been defined to be the part of the Web that cannot be indexed by search engines, including databases and dynamically generated pages. Some authors have recognized that this is a quite subjective concept that depends on the point of view of the observer: what is visible for one observer may be invisible for others....

  7. Todos los niños invisibles (All the invisible children)

    OpenAIRE

    Vicente,María Eugenia; D'Assaro, Adriana

    2008-01-01

    Excluidos e invisibles son las palabras utilizadas en el informe UNICEF 2006 para caracterizar la situación de desamparo y marginalidad de millones de niños en todo el mundo. Situación recreada en esta co-producción ítalo francesa "Todos los niños invisibles", lanzada en el Festival de Venecia, obteniendo el apoyo de UNICEF y el Programa Mundial de Alimentos. Se trata de un film en el que los directores Medhi Charef, Emir Kusturika, Spike Lee, Katia Lund, Jordan y Ridley Scott, Stefano Veneru...

  8. Monitoring of heavy metal particle emission in the exhaust duct of a foundry using LIBS.

    Science.gov (United States)

    Dutouquet, C; Gallou, G; Le Bihan, O; Sirven, J B; Dermigny, A; Torralba, B; Frejafon, E

    2014-09-01

    Heavy metals have long been known to be detrimental to human health and the environment. Their emission is mainly considered to occur via the atmospheric route. Most of airborne heavy metals are of anthropogenic origin and produced through combustion processes at industrial sites such as incinerators and foundries. Current regulations impose threshold limits on heavy metal emissions. The reference method currently implemented for quantitative measurements at exhaust stacks consists of on-site sampling of heavy metals on filters for the particulate phase (the most prominent and only fraction considered in this study) prior to subsequent laboratory analysis. Results are therefore known only a few days after sampling. Stiffer regulations require the development of adapted tools allowing automatic, on-site or even in-situ measurements with temporal resolutions. The Laser-Induced Breakdown Spectroscopy (LIBS) technique was deemed as a potential candidate to meet these requirements. On site experiments were run by melting copper bars and monitoring emission of this element in an exhaust duct at a pilot-scale furnace in a French research center dedicated to metal casting. Two approaches designated as indirect and direct analysis were broached in these experiments. The former corresponds to filter enrichment prior to subsequent LIBS interrogation whereas the latter entails laser focusing right through the aerosol for detection. On-site calibration curves were built and compared with those obtained at laboratory scale in order to investigate possible matrix and analyte effects. Eventually, the obtained results in terms of detection limits and quantitative temporal monitoring of copper emission clearly emphasize the potentialities of the direct LIBS measurements. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Pre-equilibrium particle emission in the heavy ion collisions at intermediate energy

    Science.gov (United States)

    Bellia, G.; Agodi, C.; Alba, R.; Coniglione, R.; Zoppo, A. Del; Finocchiaro, P.; Loukachine, K.; Maiolino, C.; Migneco, E.; Peghaire, A.; Piattelli, P.; Santonocito, D.; Sapienza, P.

    Hard photons and high energy protons from Ar and Xe induced reactions at 44 MeV/u were analysed in a series of experiments performed with the detector MEDEA. A careful analysis shows a strong correlation between hard γ and fast protons giving an unambiguous signature of the n-p first chance bremsstrahlung hypothesis. Some preliminary results on the emission of fast protons are reported.

  10. Genotoxic potential of organic extracts from particle emissions of diesel and rapeseed oil powered engines.

    Science.gov (United States)

    Topinka, Jan; Milcova, Alena; Schmuczerova, Jana; Mazac, Martin; Pechout, Martin; Vojtisek-Lom, Michal

    2012-07-07

    The present study was performed to identify possible genotoxicity induced by organic extracts from particulate matter in the exhaust of two typical diesel engines run on diesel fuel and neat heated fuel-grade rapeseed oil: a Cummins ISBe4 engine tested using the World Harmonized Steady State Test Cycle (WHSC) and modified Engine Steady Cycle (ESC) and a Zetor 1505 engine tested using the Non-Road Steady State Cycle (NRSC). In addition, biodiesel B-100 (neat methylester of rapeseed oil) was tested in the Cummins engine run on the modified ESC. Diluted exhaust was sampled with high-volume samplers on Teflon coated filters. Filters were extracted with dichlormethane (DCM) and DNA adduct levels induced by extractable organic matter (EOM) in an acellular assay of calf thymus DNA coupled with (32)P-postlabeling in the presence and absence of rat liver microsomal S9 fraction were employed. Simultaneously, the chemical analysis of 12 priority PAHs in EOM, including 7 carcinogenic PAHs (c-PAHs) was performed. The results suggest that diesel emissions contain substantially more total PAHs than rapeseed oil emissions (for the ESC) or that these concentrations were comparable (for the WHSC and NRSC), while c-PAHs levels were comparable (for the ESC) or significantly higher (for the WHSC and NRSC) for rapeseed oil emissions. DNA adduct levels induced by diesel and rapeseed oil derived EOM were comparable, but consistently slightly higher for diesel than for rapeseed oil. Highly significant correlations were found between 12 priority PAHs concentrations and DNA adduct levels (0.980; pparticulate emissions from the combustion of rapeseed oil is significant and is comparable to that from the combustion of diesel fuel. A more detailed study is ongoing to verify and extent these preliminary findings. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  11. Fluorescence of Bacteria, Pollens, and Naturally Occurring Airborne Particles: Excitation/Emission Spectra

    Science.gov (United States)

    2009-02-01

    have important effects on climate, through scattering and absorbing light, and acting as cloud condensation nuclei (17–19). Improved real-time...from polymerization and other reactions of volatile terpenes released by plants are not considered biological by at least some researchers. Humic...has a higher energy per photon absorbed , and this energy is higher than that of the photons emitted from NADH or riboflavin, but the emission is

  12. A Study and Brief Investigation on Invisibility Of Aircrafts (Vimanas

    Directory of Open Access Journals (Sweden)

    A.Hemant Kumar Yadav

    2015-01-01

    Full Text Available Making aircrafts invisible to human eye would be a great advantage in defence and military use. The Vedas show us evidence that the ancient ancestors have advanced technology to make a vimana invisible. They had great knowledge on the sun rays, and energies extraction which can create the invisibility for the vimana. The paper describes the various writings and investigation on the topics, comparing with the modern findings of solar rays usage which lead to the better understanding of Ancient advanced vimanas and provide a path to the findings of invisibility

  13. Role of grain size and particle velocity distribution in secondary electron emission in space plasmas

    Science.gov (United States)

    Chow, V. W.; Mendis, D. A.; Rosenberg, M.

    1993-01-01

    By virtue of being generally immersed in a plasma environment, cosmic dust is necessarily electrically charged. The fact that secondary emission plays an important role in determining the equilibrium grain potential has long been recognized, but the fact that the grain size plays a crucial role in this equilibrium potential, when secondary emission is important, has not been widely appreciated. Using both conducting and insulating spherical grains of various sizes and also both Maxwellian and generalized Lorentzian plasmas (which are believed to represent certain space plasmas), we have made a detailed study of this problem. In general, we find that the secondary emission yield delta increases with decreasing size and becomes very large for grains whose dimensions are comparable to the primary electron penetration depth, such as in the case of the very small grains observed at comet Halley and inferred in the interstellar medium. Moreover, we observed that delta is larger for insulators and equilibrium potentials are generally more positive when the plasma has a broad non-Maxwellian tail. Interestingly, we find that for thermal energies that are expected in several cosmic regions, grains of different sizes can have opposite charge, the smaller ones being positive while the larger ones are negative. This may have important consequences for grain accretion in polydisperse dusty space plasmas.

  14. Testing Invisible Momentum Ansatze in Missing Energy Events at the LHC arXiv

    CERN Document Server

    Kim, Doojin; Moortgat, Filip; Pape, Luc

    We consider SUSY-like events with two decay chains, each terminating in an invisible particle, whose true energy and momentum are not measured in the detector. Nevertheless, a useful educated guess about the invisible momenta can still be obtained by optimizing a suitable invariant mass function. We review and contrast several proposals in the literature for such ansatze: four versions of the M_T2-assisted on-shell reconstruction (MAOS), as well as several variants of the on-shell constrained M_2 variables. We compare the performance of these methods with regards to the mass determination of a new particle resonance along the decay chain from the peak of the reconstructed invariant mass distribution. For concreteness, we consider the event topology of dilepton ttbar events and study each of the three possible subsystems, in both a ttbar and a SUSY example. We find that the M_2 variables generally provide sharper peaks and therefore better ansatze for the invisible momenta. We show that the performance can be ...

  15. Correlated emission of three {alpha}-particles in the {beta}-decay of {sup 12}N

    Energy Technology Data Exchange (ETDEWEB)

    Fynbo, H.O.U.; Oinonen, M.; Weissman, L. [EP Division, CERN, CH-1211 Geneve 23 (Switzerland); Prezado, Y.; Borge, M.J.G.; Tengblad, O. [Instituto Estructura de la Materia, CSIC, Serrano 113bis, E-28006 Madrid (Spain); Aeystoe, J.; Dendooven, P.; Huang, W.; Huikari, J.; Jones, P.; Wang, Y. [Department of Physics, University of Jyvaeskylae, FIN-40351 Jyvaeskylae (Finland); Bergmann, U.C.; Jeppesen, H.; Riisager, K.; Vogelius, I.S. [Institut for Fysik og Astronomi, Aarhus Universitet, DK-8000 Aarhus C (Denmark); Jonson, B.; Meister, M.; Nyman, G. [Experimentell Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden); Rolander, K.W. [Fysiska Institutionen, Stockholms Universitet, Box 6730, S-113 85 Stockholm (Sweden)

    2002-10-01

    The {beta}-decay of {sup 12}N is used to populate {alpha}-emitting excited states in {sup 12}C. The {alpha}-particles from the break-up of both the 10.3 MeV and 12.71 MeV states were measured in coincidence with an efficient detector setup consisting of two double-sided Si strip detectors. The break-up of the 12.71 MeV 1{sup +} state is an interesting testing ground for the different descriptions of multi-particle break-up, whereas the properties of the 10.3 MeV state, which under some astrophysical conditions is relevant for the production of {sup 12}C in stars, are poorly known. First results from the analysis of the data is presented and compared with Monte Carlo simulations. (orig.)

  16. A statistical model for simulating the emission of light particles from excited nuclei

    Science.gov (United States)

    Sannikov, A. V.; Savitskaya, E. N.

    2016-05-01

    The algorithms and basic equations of a novel evaporation model that have been implemented in the program package EVAP15 are detailed. The level density of an excited nucleus is described by the composite Gilbert-Cameron formula with parameter values as suggested by the IAEA working group RIPL-3. Special attention is paid to the cross sections of inverse reactions and, in particular, to those for the interactions of low-energy neutrons with nuclei and for crossing of the Coulomb barrier by low-energy charged particles. The model predictions are compared with a large volume of experimental data on the spectra of particles emitted in the reactions ( n, xn), ( n, xp), and ( n, xα) induced by neutrons with energy near 14 MeV and on the four spectra for the reaction ( p, xp) induced by 62-MeV protons.

  17. Study of the $\\beta$-delayed Particle Emission of $^{17}$Ne

    CERN Multimedia

    2002-01-01

    We intend to investigate the charged particle decay modes from the excited states of $^{17}$F populated in the $\\beta^+$- decay of $^{17}$Ne. In particular, we propose to study the proton decay branches to $^{16}$O states which are unstable to $\\alpha$- decay. We plan to use the recently developed ISOLDE Si-ball detector array in order to efficiently detect the charged particles in a wide solid angle. We ask for a total of 12 shifts, including 9 shifts for $^{17}$Ne and 3 shifts for stable beam and calibrations. We request the use of a Mg oxide target coupled to a plasma ion source with cooled transfer line or, if possible, to the new MINIMONOECRIS. We would like to make use of the ISOLDE VME DAQ and CERN data storage system.

  18. Joint Experiments on X-ray/Particle Emission from Plasmas Produced by Laser Irradiating Nano Structured Targets

    Science.gov (United States)

    Hegazy, H.; Allam, S. H.; Chaurasia, S.; Dhareshwar, L.; El-Sherbini, Th. M.; Kunze, H.-J.; Mank, G.; McDaniel, D. H.; Rosinski, M.; Ryc, L.; Stewart, B.; Wolowski, J.; Abd El-Ghany, H.; Abd El-Latif, G.; Abd El-Rahim, F. M.; Bedrane, Z.; Diab, F.; Farrag, A.; Hedwig, R.; Helal, A.; Pardede, M.; Refaie, A.; Sharkawy, H.; El-khatim, A., Sir

    2008-04-01

    The 1st Joint (Host Laboratory) Experiment on laser plasma involving more than twenty scientists from eight countries has been carried out at the Laser and New Materials Laboratory, Faculty of Science, Cairo University, Egypt. It was co-ordinated by the International Atomic Energy Agency (IAEA) and supported through the IAEA and the ICTP (International Centre for Theoretical Physics, Trieste). The main experimental programme was aimed at characterising the possible enhancement of x-ray and particle emission from plasmas produced by laser incidence on nano-structured targets. Laser beams at 1.064 μm of 250 mJ and 532 nm of 165 mJ focused at the target surface using a nanosecond laser type Quantel were used in the present study. In the present experiments nano-copper structures evaporated onto copper bulk disks and nano-gold structures evaporated onto gold ones were used. The thickness of the nano-materials on their bulk material was 1 μm. An ion collector and x-ray semiconductor diode were used to study the ion and x-ray emission, respectively. Both were positioned at the same port at 90° with respect to the target surface and at 90 cm from the surface in the case of the ion collector and 55 cm in the case of the x-ray detector. These experiments were performed at vacuum pressures of (5—8)×10-6 mbar. Comparison of both studies in the case of nano structured targets and bulk targets were performed at different laser fluencies (1×109-1×1012 W/cm2) on the target. A 20% increase of the X-ray emission for nano gold with respect to bulk gold was observed, however, the x-ray emission in the of nano copper and copper was the same.

  19. Monitoring sand particle concentration in multiphase flow using acoustic emission technology

    OpenAIRE

    El-Alej, Mohamed Essid

    2014-01-01

    Multiphase flow is the simultaneous flow of two or several phases through a system such as a pipe. This common phenomenon can be found in the petroleum and chemical engineering industrial fields. Transport of sand particles in multiphase production has attracted considerable attention given sand production is a common problem especially to the oil and gas industry. The sand production causes loss of pipe wall thickness which can lead to expensive failures and loss of product...

  20. Origin of Nonthermal Emission from the Fermi Bubbles and Mechanisms of Particle Acceleration There

    CERN Document Server

    Dogiel, V A; Chernyshov, D O; Ko, C -M

    2013-01-01

    We analyse processes of particle acceleration in the Fermi Bubbles. The goal of our investigations is to obtain restrictions for acceleration mechanisms. Our analysis of the three processes: acceleration from background plasma, re-acceleration of relativistic electrons emitted by supernova remnants, and acceleration by shocks generated by processes of star tidal disruption in the Galactic Center, showed that the model of multi-shock acceleration does not have serious objections at present and therefore seems us more attractive than others.

  1. Emission of spherical cesium-bearing particles from an early stage of the Fukushima nuclear accident

    OpenAIRE

    Kouji Adachi; Mizuo Kajino; Yuji Zaizen; Yasuhito Igarashi

    2013-01-01

    The Fukushima nuclear accident released radioactive materials into the environment over the entire Northern Hemisphere in March 2011, and the Japanese government is spending large amounts of money to clean up the contaminated residential areas and agricultural fields. However, we still do not know the exact physical and chemical properties of the radioactive materials. This study directly observed spherical Cs-bearing particles emitted during a relatively early stage (March 14–15) of the acci...

  2. Alpha-particle emissivity screening of materials used for semiconductor manufacturing

    Science.gov (United States)

    Gordon, Michael; Rodbell, Kenneth

    2015-03-01

    Single-Event Upsets (SEU's) in semiconductor memory and logic devices continue to be a reliability issue in modern CMOS devices. SEU's result from deposited charge in the Si devices caused by the passage of ionizing radiation. With technology scaling, the device area decreases, but the critical charge required to flip bits decreases as well. The interplay between both determines how the SEU rate scales with shrinking device geometries and dimensions. In order to minimize the alpha-particle component of SEU, the radiation in the device environment has to be at the Ultra-Low Alpha (ULA) activity levels, e.g. less than 2 α/khr-cm2. Most detectors have background levels that are significantly larger than that level which makes making these measurements difficult and time consuming. A new class of alpha particle detector, utilizing pulse shape discrimination, is now available which allows one to make measurements quickly with ultra-low detector background. This talk will discuss what is involved in making alpha particle measurements of materials in the ULA activity levels, in terms of calibration, radon adsorption mitigation, the time required for obtaining reasonable statistics and comparisons to other detectors.

  3. Search for B0 Decays to Invisible Final States and to $v\\overline{v} {gamma}$

    CERN Document Server

    Aubert, B; Barate, R; Boutigny, D; Couderc, F; Gaillard, J M; Hicheur, A; Karyotakis, Yu; Lees, J P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, Michael T; Shelkov, V G; Wenzel, W A; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morgan, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Wilson, F F; Çuhadar-Dönszelmann, T; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Thiessen, D; Khan, A; Kyberd, P; Teodorescu, L; Blinov, V E; Druzhinin, V P; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M A; Mommsen, R K; Röthel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Foulkes, S D; Gary, J W; Shen, B C; Wang, K; Del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S M; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Smith, J G; Zhang, J; Zhang, L; Chen, A; Harton, J L; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q L; Altenburg, D; Brandt, T; Brose, J; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Petzold, A; Schubert, J; Schubert, Klaus R; Schwierz, R; Spaan, B; Sundermann, J E; Bernard, D; Bonneaud, G R; Brochard, F; Grenier, P; Schrenk, S; Thiebaux, C; Vasileiadis, G; Verderi, M; Bard, D J; Clark, P J; Lavin, D; Muheim, F; Playfer, S; Xie, Y; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Finocchiaro, G; Patteri, P; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Taylor, G P; Charles, M J; Grenier, G J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F R; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Chavez, C A; Coleman, J P; Forster, I J; Fry, J R; Gabathuler, Erwin; Gamet, R; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Cormack, C M; Harrison, P F; Di Lodovico, F; Mohanty, G B; Brown, C L; Cowan, G; Flack, R L; Flächer, H U; Green, M G; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Lafferty, G D; Lyon, A J; Williams, J C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts,